U.S. patent application number 14/905745 was filed with the patent office on 2016-06-02 for process for preparing torrefied biomass material using a combustible liquid.
The applicant listed for this patent is TORREFUSION TECHNOLOGIES INC.. Invention is credited to Paul Adams, John Goodwin, J. Moon, Larry Brent Taylor, Brent Wiren.
Application Number | 20160152911 14/905745 |
Document ID | / |
Family ID | 52345656 |
Filed Date | 2016-06-02 |
United States Patent
Application |
20160152911 |
Kind Code |
A1 |
Wiren; Brent ; et
al. |
June 2, 2016 |
Process for Preparing Torrefied Biomass Material Using a
Combustible Liquid
Abstract
A process for preparing torrefied densified biomass and/or
torrefied densified biosolids comprising about 2% to about 25% w/w
combustible liquid is disclosed. The process involves densifying
biomass and/or biosolids, or providing a densified biomass and/or
densified biosolids, and submerging the densified material in a hot
combustible liquid for about 2 to about 120 minutes until the
densified material is torrefied. The combustible liquid may be
derived from any source exemplified by an oil such as those derived
from plant, marine and animal sources, or alternatively, a
petroleum product. The combustible liquid is heated to a
temperature in the range of about 160.degree. C. to about
320.degree. C. prior to submersion of the densified biomass
material. Also disclosed is a biomass torrefied densified biomass
and/or torrefied densified biosolid comprising about 2% to about
25% w/w combustible liquid.
Inventors: |
Wiren; Brent; (Vancouver,
CA) ; Adams; Paul; (Vancouver, CA) ; Moon;
J.; (Vancouver, CA) ; Goodwin; John;
(Vancouver, CA) ; Taylor; Larry Brent; (Vancouver,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TORREFUSION TECHNOLOGIES INC. |
Vancouver |
|
CA |
|
|
Family ID: |
52345656 |
Appl. No.: |
14/905745 |
Filed: |
July 17, 2014 |
PCT Filed: |
July 17, 2014 |
PCT NO: |
PCT/CA2014/050679 |
371 Date: |
January 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61847399 |
Jul 17, 2013 |
|
|
|
61953519 |
Mar 14, 2014 |
|
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Current U.S.
Class: |
44/590 |
Current CPC
Class: |
Y02E 50/10 20130101;
Y02E 50/30 20130101; C10L 5/447 20130101; C10L 2290/06 20130101;
Y02P 20/145 20151101; Y02E 50/32 20130101; C10L 9/083 20130101;
Y02E 50/14 20130101; Y02E 50/15 20130101; C10B 53/02 20130101; C10L
2290/24 20130101; C10L 2200/0469 20130101 |
International
Class: |
C10L 5/44 20060101
C10L005/44; C10L 9/08 20060101 C10L009/08 |
Claims
1. A torrefied densified biomass prepared by torrefying a densified
biomass feedstock in a combustible liquid, the torrefied densified
biomass comprising about 2% to about 25% w/w of the combustible
liquid.
2. The torrefied densified biomass of claim 1, wherein the
combustible liquid is a plant-derived oil.
3. The torrefied densified biomass of claim 2, wherein the
plant-derived oil is canola oil, linseed oil, sunflower oil,
safflower oil, corn oil, peanut oil, palm oil, soybean oil,
rapeseed oil, cottonseed oil, palm kernel oil, coconut oil, sesame
seed oil, olive oil, or a combination thereof.
4. The torrefied densified biomass of claim 1, wherein the
combustible liquid is a petroleum-based oil or a bitumen-based
oil.
5. The torrefied densified biomass of claim 4, wherein the
petroleum-based oil or a bitumen-based oil is a synthetic motor
oil, a synthetic engine oil, a hydraulic fluid, a transmission
fluid, an automatic transmission fluid, a chainsaw bar and chain
oil, a gear oil, a diesel fuel, a paraffin wax, or a combination
thereof.
6. The torrefied densified biomass of claim 1, wherein the
densified biomass feedstock is derived from a plant material.
7. The torrefied densified biomass of claim 6, wherein the plant
material is wood waste from wood-processing operations, sawdust,
wood chips, straw, bagasse, waste streams from plant processing
operations, processed from crops, or a combination thereof.
8. The torrefied densified biomass of claim 1, wherein the
densified biomass feedstock comprises biosolids.
9. The torrefied densified biomass of claim 1, having a heat energy
value of about 6,000 BTU per pound to about 13,000 BTU per
pound.
10. The torrefied densified biomass of claim 1, having a heat
energy value of about 22 gigajoules per metric tonne (GJ/T) to
about 27 GET on a bone dry basis.
11. The torrefied densified biomass of claim 1 having a carbon
content of about 54 carbon % to about 63 carbon % on a bone dry
basis.
12. A process for preparing a torrefied densified biomass,
comprising the steps of: (a) densifying a supply of a biomass
feedstock to obtain a densified biomass material; (b) submerging
the densified biomass material in a combustible liquid, the
combustible liquid at a temperature between about 160.degree. C.
and about 320.degree. C.; (c) torrefying the densified biomass
material in the combustible liquid for about 2 minutes to about 120
minutes to produce the torrefied densified biomass; and (d)
recovering the torrefied densified biomass; wherein the torrefied
densified biomass comprises about 2% to about 25% w/w of the
combustible liquid.
13. A process for preparing a torrefied densified biomass,
comprising the steps of: (a) providing a supply of densified
biomass material; (b) submerging the densified biomass material in
a combustible liquid, the combustible liquid at a temperature
between about 160.degree. C. and about 320.degree. C.; (c)
torrefying the densified biomass material in the combustible liquid
for about 2 minutes to about 120 minutes to produce the torrefied
densified biomass; and (d) recovering the torrefied densified
biomass; wherein the torrefied densified biomass comprises about 2%
to about 20% w/w of the combustible liquid.
14. A process for producing torrefied pellets, comprising the steps
of: (a) densifying a supply of a biomass feedstock and extruding
therefrom densified pellets; (b) conveying the densified pellets
into and through an input end of a torrefusion reactor; (c)
submerging the densified pellets in a combustible liquid contained
within the torrefusion reactor, the combustible liquid having a
temperature between about 160.degree. C. and about 320.degree. C.;
(d) conveying the submerged densified pellets from the input end to
an output end of the torrefusion reactor for a period of time from
about 2 minutes to about 120 minutes, wherein the densified pellets
are torrefied and heat and gases are produced during torrefaction;
(e) discharging the torrefied pellets from the output end of the
torrefusion reactor and conveying the torrefied pellets into and
through a cooler; and (f) cleaning the cooled torrefied pellets to
produce cleaned torrefied pellets, the cleaned torrefied pellets
comprising about 2% to about 20% w/w of the combustible liquid.
15. The process of any of claims 12-14, wherein the supply is
provided continuously, or semi-continuously, or in batches.
16. The process of claim 14, wherein the cleaning step (f)
comprises a screening process to separate fines from the cooled
torrefied pellets.
17. The process of claim 14, wherein the cooler of step (e) is a
water cooler and the cleaning step (f) comprises washing the cooled
torrefied pellets in water contained within the water cooler to
remove residual combustible liquid from outer surfaces of the
cooled torrefied pellets.
18. The process of any of claims 12-14, further comprising the
steps of: (a) combining in a torgas heater the torrefusion gases
and heat produced during torrefusion, and combusting therein to
produced heated air; and (b) using the heated air to heat the
combustible liquid contained within the torrefusion reactor.
19. The process of claim 16, further comprising the steps of: (a)
producing thermal energy from the separated fines; (b) combining in
a torgas burner the thermal energy with the torrefusion gases and
heat produced during torrefusion; (c) combusting the combined
thermal energy and torrefusion gases and heat in the torgas burner
to produce heated air; and (d) heating the combustible liquid
contained within the torrefusion reactor using the heated air.
20. The process of claim 16, wherein the wash water is used to
desalinate a biomass feedstock.
Description
TECHNICAL FIELD
[0001] The present disclosure pertains to torrefied biomass and/or
biosolids, and in particular, to a torrefied densified biomass
and/or torrefied densified biosolid comprising a combustible liquid
and processes for preparing such torrefied densified biomass and/or
biosolids using a combustible liquid.
BACKGROUND
[0002] Biomass and biosolids are becoming important sources of
energy as the supply of fossil fuels decreases. Burning of
petroleum, coal and other fossil fuels also leads to pollutants and
greenhouse gases being released into the air and water. Biomass and
biosolids are renewable, produce significantly fewer greenhouse
gases than fossil fuels and are widely available. Raw biomass and
biosolids, however, generally have a low density resulting in
inefficient storage and transportation. The low energy densities
and higher moisture contents of raw biomass and biosolids also
hampers the widespread use of raw biomass and biosolids as a source
of thermal energy or as a coal replacement.
[0003] Torrefaction of raw biomass and biosolids has been developed
recently to turn the biomass and biosolids into a charcoal-like
state by slow-heating the biomass and biosolids in an oxygen-free
or low-oxygen environment to a maximum temperature of about
300.degree. C. The lack of oxygen prevents the biomass and/or
biosolids from burning, and instead, the material is torrefied.
Slow-heating biomass and biosolids also leads to loss of mass due
to the volatile organic compounds (VOCs) within the raw biomass and
biosolids being gassified. Torrefaction also causes chemical
changes to the cellular structures of the material, resulting in a
partial loss of mass and a loss in mechanical strength and
elasticity. Torrefaction, therefore, also produces a product that
has increased friability and grindability. Furthermore, torrefied
material is hydrophobic and therefore, stays dry and is insensitive
to atmospheric humidity. This reduces the risk of rotting,
overheating, and auto-ignition of the materials when stored.
[0004] Prior art torrefaction processes generally involve one of
high-pressure steam, high temperature inert gas or superheated
steam in the heat treatment processes. Other torrefaction processes
using gas or pressure or vacuum methods may also be used. Most of
these prior technologies, however, fail to efficiently and
practically convert biomass into torrefied wood in a simple, easy,
quick, practical, safe, uniform and economic way. In particular,
using any type of inert gas or steam involves large containment
systems with large amounts of surface area, high equipment costs,
high energy costs, slow treatment rates, and low overall operating
efficiencies with resultant high production costs. The systems and
equipment are complex and large for containing the inert gas or
steam heat transfer medium, and often require heavyweight materials
given the high operating pressures required with steam.
Furthermore, these systems often require more than an hour to
torrefy biomass. Consequently, the prior technologies also have
challenges with scalability.
[0005] Recent torrefaction processes have also used bio-liquids
(such as, vegetable oils, soybean oils, canola oils or animal
tallow), paraffinic hydrocarbons, oil, molten salts or paraffin, to
heat and torrefy biomass. Some of these technologies, however,
involve intricately designed housings for holding the liquids and
torrefying the biomass, and require the biomass to pass through a
plurality of pools, rivers or liquid compartments holding the
liquids during the torrefaction process. These processes,
therefore, may require additional engineering efforts, complicated
designs and large volumes of the torrefying liquids. Moreover,
these processes often involve a pre-heating stage and/or a drying
stage prior to the torrefaction treatment, thus, being costly to
operate and time-consuming.
SUMMARY
[0006] The exemplary embodiments of the present disclosure
generally pertain to a torrefied densified biomass and/or biosolid
comprising a combustible liquid and processes for preparing the
torrefied densified biomass and/or biosolid using a combustible
liquid exemplified by hydrocarbons, such as plant-derived oils,
marine-derived oils, animal-derived oils, petroleum products and
bitumen-based products.
[0007] An exemplary process for preparing a torrefied densified
biomass and/or torrefied densified biosolids of the present
disclosure is disclosed herein, in which a combustible liquid is
used for torrefying a densified biomass material and/or densified
biosolid material. The exemplary process may comprise one of two
starting materials: (i) the initial starting material may be raw
biomass and/or biosolids that undergo densification prior to
heating in the combustible liquid; or (ii) the initial starting
material may be densified biomass and/or densified biosolids that
are readily available in the marketplace.
[0008] An exemplary process of the present disclosure generally
comprises the steps of densifying raw biomass and/or biosolids;
submerging the densified material into a combustible liquid heated
to a temperature in a range of about 160.degree. C. to about
320.degree. C.; and torrefying the densified material in the heated
combustible liquid for about 2 minutes to about 120 minutes to
produce a torrefied densified biomass and/or biosolid. The
resulting torrefied densified material comprises about 2% to about
25% w/w combustible liquid. The densified biomass and/or biosolids
may be directly transferred from the densifying process into the
combustible liquid to minimize any loss of heat gained by the
biomass/biosolids densification. This may increase efficiency of
the process as the heated densified biomass and/or densified
biosolids will require less heating in the combustible liquid.
[0009] The process may further comprise a drying step
post-densification or prior to transferring the densified material
into the combustible liquid. Drying may be done in conjunction with
densification.
[0010] The starting feedstock may also comprise commercially
available densified biomass and/or densified biosolids. With such
feedstocks, the initial densification step disclosed herein is not
required.
[0011] The biomass material to be torrefied may comprise any type
of material derived from living or recently living organisms, and
are exemplified by plant biomass such as sugar-cane bagasse, corn
stover, rice straw, wheat straw, bamboo, switchgrass, and hemp. The
biomass material may also comprise wood biomass such as softwood,
hardwood, sawdust, hog fuel and wood byproducts. The biosolids may
be recovered from sewage or wastewater during a sewage treatment
process, alternatively obtained from municipal sewage treatment
processes, alternatively obtained from industrial waste streams
exemplified by fruit and vegetable processing plants and fibre
processing plants, or alternatively, may be agricultural wastes
from livestock and poultry production. The biomass and/or biosolids
may also be any combination of the feedstocks described herein.
[0012] The exemplary processes disclosed herein may also be
continuous processes, semi-continuous processes, or batch
processes. In such processes, the supply of biomass material to a
pelleter or briquetter may be continuous or semi-continuous or in
batches. Alternatively, if commercially available densified biomass
and/or densified biosolids are used, then the supply of such
densified material to the combustible liquid may be continuous or
semi-continuous or in batches.
[0013] The combustible liquid preferably comprises a hydrocarbon
exemplified by plant-derived oils, marine-derived oils,
animal-derived oils, petroleum products and bitumen-based products
that are heatable to a temperature of up to about 320.degree. C.
The combustible liquid may be derived from any source such as, for
example, an oil derived from a plant source, a marine source, an
animal source, a petroleum product and a bitumen-based product. For
example, the combustible liquid may be canola oil, linseed oil,
sunflower oil, safflower oil, corn oil, peanut oil, palm oil,
soybean oil, rapeseed oil, cottonseed oil, palm kernel oil, coconut
oil, sesame seed oil, olive oil, animal tallow, fish oil, liver
oil, and mixtures thereof. Alternatively, the combustible liquid
may be a petroleum-based oil or a bitumen-based oil, such as, for
example, a synthetic motor oil or engine oil exemplified by 5W-30
and 10W-30 engine oil; a chainsaw bar oil; a chain oil;
transmission fluid oils and fluids exemplified by automatic
transmission fluids (ATF); hydraulic fluids; gear oils; diesel
fuel; paraffin wax; paraffin oil; kerosene, stove oil; and mixtures
thereof
[0014] The torrefied densified biomass and/or biosolid disclosed
herein and obtained from the processes described herein may absorb
between about 2% and 25% w/w combustible liquid during the
torrefaction process, and may have a heat energy value of about
6,000 BTU per pound on a bone dry basis to about 13,000 BTU per
pound on a bone dry basis, or any amount therebetween. The heat
energy value may also be expressed in gigajoules per metric tonne
(GJ/t), with the torrefied densified biomass and/or biosolid
obtained from the processes described herein having a heat energy
value of about 22 GJ/t on a bone dry basis to about 27 GJ/t on a
bone dry basis, or any amount therebetween.
[0015] The torrefied densified biomass and/or biosolid disclosed
herein and obtained from the processes described herein may also
comprise a carbon content of about 50 carbon % on a bone dry basis
to about 65 carbon % on a bone dry basis and may also be
hydrophobic in nature.
[0016] The exemplary processes disclosed herein may also include a
gas collection and condenser system for collecting and separating
VOCs, vapours and steam expelled and/or generated during the
densification, drying and torrefaction processes, for condensation
and separation into reusable energy sources.
DESCRIPTION OF THE DRAWINGS
[0017] The present disclosure will be described in conjunction with
reference to the following drawings in which:
[0018] FIG. 1 is a schematic flowchart showing an exemplary process
for preparing a torrefied densified biomass material and/or a
torrefied densified biosolid material;
[0019] FIG. 2 is schematic flowchart showing a second exemplary
process for preparing a torrefied densified biomass material and/or
a torrefied densified biosolid material;
[0020] FIG. 3 is a schematic flowchart showing an exemplary process
for densification and torrefaction of a biomass feedstock;
[0021] FIG. 4 is a schematic flowchart showing an exemplary process
for densification and torrefaction of a hog fuel feedstock;
[0022] FIG. 5(A) is a perspective top-side view of an exemplary
embodiment of a torrefusion reactor for use in a continuous,
semi-continuous or batch throughput torrefaction process of the
present disclosure, showing torrefied pellets being transported out
of a combustible liquid; FIG. 5(B) is a perspective top-side view
of an exemplary alternative embodiment of a torrefusion reactor for
use in a continuous, semi-continuous or batch throughput
torrefaction process of the present disclosure, with densified
biomass and/or densified biosolids being loaded in a densified
biomass/biosolids metering bin;
[0023] FIG. 6(A) is a perspective top-side view of the torrefusion
reactor shown in FIG. 5(B), showing torrefied pellets being
transported out of a combustible liquid; and FIG. 6(B) is a
perspective top-side view of the torrefusion reactor shown in FIG.
5(B), showing the direction of rotation of the conveyor of the
torrefusion reactor as densified biomass and/or densified biosolids
proceed through the continuous, semi-continuous or batch throughput
torrefaction process of the present disclosure;
[0024] FIG. 7 is a chart showing physicochemical changes that occur
in a biomass feedstock over a period of time during processing with
an exemplary torrefaction process disclosed herein;
[0025] FIG. 8 is a graph showing the heat value of biomass
feedstock that has been processed with an exemplary torrefaction
process disclosed herein, wherein the biomass feedstock has been
processed at different temperatures for different periods of
time;
[0026] FIG. 9 is a graph showing the heat value of biomass
feedstock that has been processed with an exemplary torrefaction
process disclosed herein, wherein the biomass feedstock has been
processed at different temperatures for different periods of
time;
[0027] FIG. 10 is a graph showing the carbon content of a biomass
feedstock that has been processed with an exemplary torrefaction
process disclosed herein, wherein the biomass feedstock has been
processed at different temperatures for different periods of
time;
[0028] FIG. 11 is a graph showing the mass of biomass feedstock and
the oil absorption by biomass feedstock that has been processed for
different time periods using canola oil as the combustible
liquid;
[0029] FIG. 12 is a graph showing the mass of biomass feedstock and
the oil absorption by biomass feedstock that has been processed for
different time periods using paraffin wax as the combustible
liquid;
[0030] FIG. 13 is a graph showing a comparison between the total
losses of combustible liquids canola oil and paraffin wax in an
exemplary torrefaction process according to the present
disclosure;
[0031] FIG. 14 is a graph showing a comparison between the
reductions in weight of biomass feedstock (in %) when canola oil or
paraffin wax are used as the combustible liquids in an exemplary
torrefaction process according to the present disclosure;
[0032] FIG. 15 is a graph showing comparisons of water absorption
by biomass feedstocks that have been processed at different
temperatures for different periods of time in an exemplary
torrefaction process according to the present disclosure;
[0033] FIG. 16 is a graph showing comparisons of water absorption
by biomass feedstocks that have been processed for increasing time
periods and at increasing time periods with an exemplary
torrefaction process of the present disclosure;
[0034] FIG. 17 is a graph showing total oil absorptions by biomass
feedstock processed with different types of oil as combustible
liquids with an exemplary torrefaction process of the present
disclosure;
[0035] FIG. 18 is a graph showing total oil absorptions by biomass
feedstock processed with different types of oil as combustible
liquids with an exemplary torrefaction process of the present
disclosure; and
[0036] FIG. 19 is a perspective side view of a small-scale
torrefusion reactor suitable for use in some of the exemplary
torrefaction processes disclosed herein.
DETAILED DESCRIPTION
[0037] The exemplary embodiments of the present disclosure pertain
to torrefied densified biomass and/or torrefied densified biosolids
comprising a combustible liquid exemplified by hydrocarbons. Some
exemplary embodiments pertain to processes for preparing a
torrefied densified biomass and/or torrefied densified biosolids
comprising a combustible liquid. Suitable combustible liquids are
exemplified by plant-derived oils, marine-derived oils,
animal-derived oils, petroleum-based products and bitumen-based
products.
[0038] The exemplary torrefaction processes disclosed herein
require a reduced energy consumption as compared to prior art
processes, while improving process efficiency and feedstock
throughput. Energy exemplified by VOCs and steam, produced during
the process, may be recycled through the system to heat the
combustible liquid, and/or to create pellets for torrefaction,
and/or to torrefy the densified biomass. It was surprisingly found
that minimal oil is actually absorbed by the densified biomass
during the present torrefaction processes. Accordingly, the
combustible liquids used during the torrefaction steps may be
repeatedly recycled and reused to process additional biomass
feedstocks, thus reducing input costs. Furthermore, any type of oil
may be used for these processes, including less valuable and
cheaper oils that may have high contents of unsaturated fats,
thereby even further reducing input costs. It is to be noted that
use of a densified material as a biomass feedstock will reduce
torrefaction processing time, as demonstrated in the Examples
provided herein.
[0039] The torrefaction processes disclosed herein also do not
require a vast amount of space to operate and are easily assembled
and used, especially given that the various steps of the process do
not need to occur within a wholly connected system. The dryer,
densifier, receiving container for torrefaction, and cooling system
may all be stored separately and set up in independent
locations.
[0040] Moreover, the torrefaction processes disclosed herein
provide an improved quality of torrefied densified biomass as the
residual oil on the surface of the torrefied densified biomass
reduces the amount of dust and other combustible materials on the
biomass' surface. The torrefied densified biomass produced by the
exemplary processes is therefore hydrophobic. Accordingly, the
exemplary processes produce a torrefied densified product that is
easily transportable and shippable as it does not create an
explosion hazard. The torrefied densified product can readily be
used as a biofuel.
[0041] Suitable biomass feedstocks for exemplary processes and
products disclosed herein include harvested plant materials
exemplified by hardwood trees and softwood trees which may have
been processed into chips and/or sawdust and/or pellets, including
briquettes, and/or debris and wood waste from wood-processing
operations, fibrous annual or perennial crops such as Salix,
switchgrass, corn stover, straws produced from harvesting of
cereals and/or oilseed crops; or material obtained from waste
streams produced from fruit processing plants or vegetable
processing plants or cereals processing plants or oilseeds
processing plants, or obtained from bagasse from sugar cane. Also
suitable are biosolids materials. As used herein, "biosolids" means
any solid or semisolid organic material recovered from sewage or
wastewater during a sewage treatment process, obtained from
municipal sewage treatment processes, or alternatively, may be
agricultural wastes from livestock and poultry production.
[0042] The use of biomass materials has been limited as biomass
generally has a lower energy content and lower energy density
compared to traditional fossil fuels. The present disclosure
pertains to a densified or pelletized biomass material, including
biomass densified into briquettes, as the starting material for
torrefaction to increase the starting energy of the raw biomass
material (for example, pelletized or otherwise densified biomass,
such as briquettes, on a dry basis, can have an energy value of up
to 40 lbs/cu ft, as compared to 8 lbs/cu ft for loose biomass
material). As understood in the art, densification is a process for
increasing the density of the biomass, and many forms of densified
biomass are readily available, such as wood pellets and briquettes.
Moreover, various procedures for densifying biomass are known in
the art and may be employed in the present process, such as, but
not limited to, extrusion, briquetting, pelleting and
agglomeration.
[0043] The term "densified" as used herein means a biomass material
that has been compressed to increase its density. The densified
biomass material will be understood to be various shaped modules of
biomass, with the individual pieces having uniform shapes or
non-non-uniform shapes.
[0044] The term "pelletized" as used herein means a biomass
material that has been compacted or concentrated into pellets, or
pressed into briquettes. The pellets may be of any shape such as
those exemplified by cubes, pellets, pucks, briquettes, and
synthetic logs, wherein the individual pieces have uniform shapes
or non-non-uniform shapes. The briquettes may also be of any shape
such as exemplified by squares, rectangles, triangles,
quadrilaterals, or any regular polygon (such as, for example,
pentagons, heptagons, octagons and the like) or alternatively
irregular polygons. The individual pieces may have uniform shapes
or non-uniform shapes, asymmetric shapes or symmetric shapes.
[0045] Hereinafter, the term "densified" shall refer to densified
and pelletized materials collectively, including, without
limitation, pellets and briquettes, which retain some moisture
content, such as, for example, an initial moisture content in the
densified biomass and/or biosolids material of at least about 1%.
The densified biomass and/or biosolids material may also have an
initial moisture content of at least about 1.5%, at least about 2%,
at least about 2.5%, at least about 3%, at least about 3.5%, at
least about 4%, at least about 4.5%, at least about 5%, at least
about 5.5%, at least about 6%, at least about 6.5%, at least about
7%, at least about 7.5%, at least about 8%, at least about 8.5%, at
least about 9%, at least about 9.5%, at least about 10%, at least
about 11%, at least about 12%, at least about 13%, at least about
14%, at least about 15%, at least about 16%, at least about 17%, at
least about 18%, at least about 19%, at least about 20%, or any
moisture content therebetween.
[0046] The term "densification" used herein shall refer to
densification, pelletization and briquetting processes.
Furthermore, the densified biomass material may also be referred to
as "pellets," "cubes" or "briquettes" herein. However, it should be
understood that the densified biomass referred to herein does not
include charcoal briquettes which are already torrefied and
therefore cannot be torrefied any further.
[0047] As used herein, the term "wet basis" or "As Received Basis"
refers to actual values or chemical measurements of a sample of
densified biomass material or a sample of torrefied densified
biomass, as obtained from an analysis of the sample, and includes,
without limitation, moisture content, % ash, % volatile matter, %
fixed carbon, % sulphur, % carbon, % nitrogen, % oxygen, and
calorific values, such as heat energy values in Btu/lb, GJ/t,
Kcal/kg.
[0048] As used herein, the term "dry basis" refers to theoretical
values that are calculated from the "wet basis" or "as received
basis" values to provide results for a sample of densified biomass
material or a sample of torrefied densified biomass as if there was
no moisture in the sample (i.e., if it was bone dry; total heat
value as though dry). Accordingly, as used herein, the term "bone
dry basis" refers to the theoretical value for a sample of
densified biomass material or a sample of torrefied densified
biomass with zero detectable moisture content.
[0049] The torrefaction processes of the present disclosure
generally pertain to immersion of densified biomass material into a
combustible liquid maintained at a temperature in the range of
about 160.degree. C. to about 320 C, for a period of time in the
range of about 2 minutes to about 120 minutes, for about 5 minutes
to about 120 minutes, for about 8 minutes to about 90 minutes, for
about 10 minutes to about 60 minutes, for about 12 minutes to about
45 minutes, or for about 15 minutes to about 30 minutes.
[0050] As used herein, the term "combustible liquid" means the
liquid for contacting and immersing therein the densified biomass
material, and then torrefying the densified biomass material in the
combustible liquid. The term "combustible liquid" may comprise a
hydrocarbon-based oil exemplified by plant-derived oils,
marine-derived oils, animal-derived oils, petroleum products and
bitumen-based products, and may also comprise a synthetic fuel or a
synthetic oil. Suitable plant-derived oils are exemplified by
canola oil, linseed oil, sunflower oil, safflower oil, corn oil,
peanut oil, palm oil, soybean oil, rapeseed oil, cottonseed oil,
palm kernel oil, coconut oil, sesame seed oil, olive oil, and
mixtures of plant-derived oils. Suitable animal-derived oils are
exemplified by animal tallow, fryer greases, and liver oil among
others, and mixtures thereof. Suitable marine-derived oils are
exemplified by whale oil, seal oil, fish oil, algal oils, and
mixtures of marine-derived oils. Suitable petroleum products are
exemplified by synthetic motor oil and engine oils such as
exemplified by 5W-30 and 10W-30 engine oils, chainsaw bar oil,
chain oil, transmission fluid oils and fluids such as automatic
transmission fluids (ATF), hydraulic fluids, gear oils, diesel
fuel, paraffin wax, paraffin oil, kerosene, and stove oil, among
others, and mixtures thereof. A suitable synthetic fuel or
synthetic oil may be produced by a Fischer Tropsch conversion
process and is exemplified by pyrolysis oil and the like. The
combustible liquid may also be any combinations of plant-derived
oils, marine-derived oils, animal-derived oils, petroleum products
and synthetic fuels or oils. The combustible liquid used in the
present disclosure may further be heatable to a temperature of up
to 320.degree. C. As used herein, the combustible liquid is for
heating densified biomass material in an oxygen-free environment to
torrefy the densified material without igniting it, rather than for
the infusion of densified biomass material with the combustible
liquid or alternatively, for causing a significant increase in
absorption of combustible liquid by densified biomass material.
[0051] The products of the torrefaction processes disclosed herein
are torrefied/densified biomass and/or biosolids material that
retain a portion of the combustible liquid and have a high degree
of hydrophobicity. The torrefied densified biomass and/or biosolid
obtained from the processes described herein may absorb between
about 2% and about 25% w/w combustible liquid during the
torrefaction process, or any amount therebetween. For example,
without limitation, the amount of combustible liquid absorbed and
retained within torrefied densified biomass may be about 2% to
about 25% w/w combustible liquid, or any amount therebetween; about
2% to about 24% w/w combustible liquid, or any amount therebetween;
about 2% to about 23% w/w combustible liquid, or any amount
therebetween; about 2% to about 22% w/w combustible liquid, or any
amount therebetween; about 2% to about 21% w/w combustible liquid,
or any amount therebetween; about 2% to about 20% w/w combustible
liquid, or any amount therebetween; about 2% to about 19% w/w
combustible liquid, or any amount therebetween; about 2% to about
18% w/w combustible liquid, or any amount therebetween; about 2% to
about 17% w/w combustible liquid, or any amount therebetween; such
as, for example, 3% w/w combustible liquid, 4% w/w combustible
liquid, 5% w/w combustible liquid, 6% w/w combustible liquid, 7%
w/w combustible liquid, 8% w/w combustible liquid, 9% w/w
combustible liquid, 10% w/w combustible liquid, 11% w/w combustible
liquid, 12% w/w combustible liquid, 13% w/w combustible liquid, 14%
w/w combustible liquid, 15% w/w combustible liquid, 16% w/w
combustible liquid, or any amount therebetween.
[0052] Those skilled in the art would understand that the biomass
and/or biosolid materials of the present disclosure have a range of
heat energy values. Those skilled in the art would know that
exemplary energy values of the densified biomass and/or biosolids
may range from about 4,300 BTU per pound to about 12,800 BTU per
pound, depending on the feedstock and the moisture content of the
feedstock. For example, a skilled person in the art would known
that wood generally has an energy content of about 6,400 BTU per
pound with 20% moisture (air dry basis) to about 7,600 to about
9,600 BTU per pound on a bone dry basis (or about 15 GJ/t with 20%
moisture to about 18-22 GJ/t on a bone dry basis), and that
agricultural residues, such as switchgrass, have an energy content
of about 4,300 BTU per pound to about 7,300 BTU per pound (or about
10-17 GJ/t), depending on the moisture content of the agricultural
residue. In addition, those skilled in the art would known that
charcoal has an energy content of about 12,800 BTU per pound.
Accordingly, a skilled person would appreciate that the range of
heat energy values following torrefaction can also vary, with those
biomass and/or biosolid material having a lower initial heat energy
value producing an end product having a lower heat energy value
compared to a biomass and/or biosolid material having a higher
initial heat energy value. In addition, as described herein,
different factors can be varied, such as, without limitation, the
density of the densified biomass, the temperature of the
combustible liquid, the submersion time of the densified biomass in
the combustible liquid, and the type of combustible liquid used, to
obtain a particular heat energy value for a torrefied densified
biomass and/or biosolid material of the present disclosure.
[0053] The torrefied densified biomass and/or biosolid of the
present disclosure may accordingly have a heat energy value of
about 6,000 BTU per pound on a bone dry basis to about 13,000 BTU
per pound on a bone dry basis, or any heat energy value
therebetween, for example, from about 6,000 BTU per pound on a bone
dry basis to about 12,000 BTU per pound on a bone dry basis, or any
heat energy value therebetween; from about 6,000 BTU per pound on a
bone dry basis to about 11,000 BTU per pound on a bone dry basis,
or any heat energy value therebetween; from about 6,000 BTU per
pound on a bone dry basis to about 10,000 BTU per pound on a bone
dry basis, or any heat energy value therebetween; from about 6,000
BTU per pound on a bone dry basis to about 9,000 BTU per pound on a
bone dry basis, or any heat energy value therebetween; from about
9,000 BTU per pound on a bone dry basis to about 13,000 BTU per
pound on a bone dry basis, or any heat energy value therebetween,
such as, for example, about 9,500 BTU per pound on a bone dry
basis; about 10,000 BTU per pound on a bone dry basis; about 10,500
BTU per pound on a bone dry basis; about 11,000 BTU per pound on a
bone dry basis; about 11,500 BTU per pound on a bone dry basis;
about 12,000 BTU per pound on a bone dry basis; about 12,500 BTU
per pound on a bone dry basis on a bone dry basis; about 13,000 BTU
per pound, or any heat energy value therebetween. The heat energy
value may also be expressed in terms of gigajoules per metric tonne
(GJ/t). The torrefied densified biomass and/or biosolid may
therefore comprise a heat energy value of about 22 GJ/t on a bone
dry basis to about 27 GJ/t on a bone dry basis, or any heat energy
value therebetween, for example, from about 22 GJ/t on a bone dry
basis to about 26.5 GJ/t on a bone dry basis or any heat energy
value therebetween; from about 22 GJ/tt on a bone dry basis to
about 26 GJ/t on a bone dry basis or any heat energy value
therebetween; from about 22 GJ/t on a bone dry basis to about 26
GJ/t on a bone dry basis or any heat energy value therebetween;
from about 22 GJ/t on a bone dry basis to about 25 GJ/t on a bone
dry basis or any heat energy value therebetween; from about 22 GJ/t
on a bone dry basis to about 24 GJ/t on a bone dry basis or any
heat energy value therebetween; or from about 22 GJ/t on a bone dry
basis to about 23 GJ/t on a bone dry basis or any heat energy value
therebetween.
[0054] Furthermore, the torrefied densified biomass disclosed
herein may have a carbon content of about 50 carbon % on a bone dry
basis to about 65 carbon % on a bone dry basis, or any amount
therebetween. For example, without limitation, the carbon content
of the torrefied densified biomass may be about 51 carbon % on a
bone dry basis, 52 carbon % on a bone dry basis, 53 carbon % on a
bone dry basis, 54 carbon % on a bone dry basis, 55 carbon % on a
bone dry basis, 56 carbon % on a bone dry basis, 57 carbon % on a
bone dry basis, 58 carbon % on a bone dry basis, 59 carbon % on a
bone dry basis, 60 carbon % on a bone dry basis, 61 carbon % on a
bone dry basis, 62 carbon % on a bone dry basis, 63 carbon % on a
bone dry basis, 64 carbon % on a bone dry basis, 65 carbon % on a
bone dry basis, or any amount therebetween.
[0055] The torrefied end products are easily grindable into
particulate and/or powdered forms that are particularly suitable
for use as fuels for generation of power and/or heat. Furthermore,
the torrefied material is easily transported and stored and are
hydrophobic in nature.
[0056] A schematic flowchart is shown in FIG. 1 that illustrates an
exemplary process of the present disclosure for preparing a
torrefied densified biomass and/or biosolid material having a
higher energy density value as compared to a non-torrefied biomass
material. In this embodiment, the starting raw biomass material 2
is not densified and the process for preparing the torrefied
densified biomass material includes initial steps of drying and
densifying raw biomass material 2 into densified biomass material
20. For the torrefaction process, a receiving container 10 is
filled with a combustible liquid 12, as described above.
Combustible liquid 12 is heated up to a temperature in a range of
about 160.degree. C. to about 320.degree. C., and densified biomass
material 20 is immersed in the hot combustible liquid 12 in
receiving container 10. Densified biomass material 20 is completely
submerged in the hot combustible liquid 12 to create an
"oxygen-free" environment. The hot combustible liquid 12 may be
maintained at a temperature in a range of about 160.degree. C. to
about 320.degree. C., or any temperature therebetween.
Alternatively, the temperature of the hot combustible liquid 12 may
be varied during the process between about 160.degree. C. and about
320.degree. C. Whether combustible liquid 12 is maintained at a
certain temperature or varied during the process, the temperature
of densified biomass 20 is increased from its initial temperature
to a temperature in a range of about 160.degree. C. to about
320.degree. C., or any temperature therebetween. During this
heating process, most of the moisture is driven out of densified
biomass 20 and densified biomass 20 takes in heat energy in an
endothermic reaction. Densified biomass 20 also undergoes chemical
and structural changes and expels some VOCs contained within
densified biomass 20. The resulting torrefied densified biomass 30
is removed from receiving container 10 and cooled in a cooling
system 32.
[0057] Any type of densification process described in the art may
be used in the present process to produce a densified biomass
material 20 for torrefaction. For example, densifier 5 may be a
pelletizer, as known in the art, and may comprise an extrusion
process for producing pellets (including, for example, a pellet
mill extruder, a screw extruder), a hammer mill, a piston press, a
wheel press or a briquetter for pressing biomass into a briquette,
or may involve agglomeration. Densification may also include the
addition of pellet binders during the densification process to
ensure that pellet quality is maintained. The densification process
may also involve pre-heating and melting of the raw biomass
material 2 through mechanical action and friction and heat,
resulting in a significant reduction of volume, elimination of some
moisture and air, and an increase in temperature of the biomass.
After raw biomass material 2 is densified, the resulting densified
biomass 20 proceeds through the torrefaction process.
[0058] The present disclosure also provides that a dryer 7 may be
used to reduce the moisture content in raw biomass material 2
before and/or after densification and before torrefaction. Those
skilled in the art will appreciate that any dryer known in the art
may be used, such as, for example, the Altentech.TM.
Biovertidryer.TM. (available from Altentech.TM. Power Inc.,
Vancouver, BC, Canada), together with densifier 5. The drying
process may be useful in further heating of the densified biomass
material 20 prior to torrefaction, thereby increasing the
efficiency of the torrefaction process.
[0059] Dryer 7 and/or densifier 5 (or a combined dryer/densifier)
may be located near receiving container 10 containing combustible
liquid 12. With such an arrangement, densified biomass 20 may be
directly transferred from densifier 5 and/or dryer 7 (or a combined
dryer/densifier) to receiving container 10 without cooling the
densified biomass 20 in-between. Those skilled in the art will
appreciate that through the action of densifiers and melding raw
material into a compact product, densifiers produce significant
heat, thus resulting in a heated densified product. Dryers known in
the art also use significant heat to extract moisture from raw
biomass, thus further increasing the heat of a densified product.
Accordingly, densified biomass 20 is at a temperature greater than
ambient temperature immediately following densification and/or
drying. Transfer of densified biomass 20 directly from densifier 5
and/or dryer 7 (or a combined dryer/densifier) to receiving
container 10 may assist in further reducing the costs of torrefying
biomass and increase the efficiency of the process as the initial
temperature of densified biomass 20 entering combustible liquid 12
is higher than ambient temperature. Alternatively, the densified
biomass 20 may be cooled before transferring from densifier 5
and/or dryer 7 (or a combined dryer/densifier) to receiving
container 10.
[0060] Importantly, the present disclosure provides for
densification prior to contact with any type of oil; that is, raw
biomass material 2 is densified prior to contacting any oil of the
combustible liquid (or densified biomass 20 is used as the starting
material). Those skilled in the art will appreciate that fat and
oil may interfere with steam absorption and reduce pelletability.
Fats and oils may be used during pelleting, but generally to
lubricate the die and ensure a smooth start-up after the die cools
off. Oil is mixed with raw biomaterial following densification to
purge the die prior to shutdown and is not for actual pelletization
of the biomass. In fact, oil-saturated biomass from a pellet press
may be saved following pelletization for reuse in a subsequent
shutdown sequence (see, for example, Kofman, P D. "The production
of wood pellets." Coford Connects, Processing/Products No. 10,
pages 1-6, 2012). Accordingly, the present disclosure provides an
improved torrefied densified biomass as compared to prior art
processes which coat biomass with oil prior to densification.
[0061] Receiving container 10 may be any type of container that can
be heated to a temperature of up to about 320.degree. C. and can
hold hot combustible liquid at a temperature of up to about
320.degree. C. for extended periods of time. It is, therefore,
understood that receiving container 10 be of a simple design. For
example, receiving container 10 may be a commercially available
deep fryer exemplified by a PITCO.RTM. fryer (PITCO is a registered
trademark of Pitco Frialator, Inc., Burlington, Vt., U.S.A.), a
VULCAN.RTM. fryer (VULCAN is a registered trademark of Vulcan-Hart
Corporation, Chicago, Ill., U.S.A.), a FRYMASTER.RTM. (FRYMASTER is
a registered trademark of Frymaster LLC, Shreveport, La., U.S.A.),
a Southbend fryer, or a DEAN.RTM. fryer (DEAN is a registered
trademark of Frymaster LLC, Shreveport, La., U.S.A.); or, receiving
container 10 may be any sized drum, tank, pot or other container
that can be heated directly from below to a temperature of about
320.degree. C., and that can hold a combustible liquid at a
temperature of about 320.degree. C. for extended periods of time.
Receiving container 10 is also sufficiently sized to receive the
desired amount of densified biomass 20 together with the
combustible liquid 12.
[0062] Combustible liquid 12 may be heated using a heat source
directly below receiving container 10 or using an external heat
source to heat the combustible liquid 12, which can be transferred
into receiving container 10 once it reaches its operating
temperature. The external heat source may be, for example, a
nuclear reactor with modest thermal output, a furnace that burns
coal or natural gas, or a portion of the produced biocoal, with or
without additional heat exchangers.
[0063] It is understood that, to minimize costs of the exemplary
processes described herein, the size of receiving container 10 and
the amount of combustible liquid 12 used may be limited to a size
and amount that is sufficient to completely submerge the particular
quantity of densified biomass 20 to be torrefied. Moreover, smaller
amounts of combustible liquid may also be used if densified biomass
20 comprises smaller-sized pellets or briquettes. Accordingly, the
exemplary processes described herein may be varied in order to make
the process more efficient and less costly, and can be adjusted
according to a user's needs.
[0064] As described above, combustible liquid 12 may be heated to a
temperature in a range of about 160.degree. C. to about 320.degree.
C., or any temperature therebetween, and the combustible liquid 12
may be maintained at this temperature during the torrefaction
process. By way of further example, the temperature that
combustible liquid 12 may be heated to and maintained at can vary
in a range of between about 180.degree. C. to about 320.degree. C.,
or any temperature therebetween; between about 180.degree. C. to
about 300.degree. C., or any temperature therebetween; between
about 200.degree. C. to about 320.degree. C., or any temperature
therebetween; between about 200.degree. C. and about 310.degree.
C., or any temperature therebetween; between about 200.degree. C.
and about 300.degree. C., or any temperature therebetween; between
about 200.degree. C. and about 290.degree. C., or any temperature
therebetween; between about 200.degree. C. and about 280.degree.
C., or any temperature therebetween; between about 200.degree. C.
and about 270.degree. C., or any temperature therebetween; between
about 200.degree. C. and about 260.degree. C., or any temperature
therebetween; between about 200.degree. C. and about 250.degree.
C., or any temperature therebetween; between about 200.degree. C.
and about 240.degree. C., or any temperature therebetween; between
about 220.degree. C. and about 300.degree. C., or any temperature
therebetween; between about 220.degree. C. and about 290.degree.
C., or any temperature therebetween; between about 220.degree. C.
and about 280.degree. C., or any temperature therebetween; between
about 220.degree. C. and about 270.degree. C., or any temperature
therebetween; between about 220.degree. C. and about 260.degree.
C., or any temperature therebetween; between about 220.degree. C.
and about 250.degree. C., or any temperature therebetween; between
about 220.degree. C. and about 240.degree. C., or any temperature
therebetween; or can be about 162.degree. C., 165.degree. C.,
168.degree. C., 170.degree. C., 172.degree. C., 175.degree. C.,
178.degree. C., 180.degree. C., 181.degree. C., 182.degree. C.,
183.degree. C., 184.degree. C., 185.degree. C., 186.degree. C.,
187.degree. C., 188.degree. C., 189.degree. C., 190.degree. C.,
191.degree. C., 192.degree. C., 193.degree. C., 194.degree. C.,
195.degree. C., 196.degree. C., 197.degree. C., 198.degree. C.,
199.degree. C., 200.degree. C., 201.degree. C., 202.degree. C.,
203.degree. C., 204.degree. C., 205.degree. C., 206.degree. C.,
207.degree. C., 208.degree. C., 209.degree. C., 210.degree. C.,
211.degree. C., 212.degree. C., 213.degree. C., 214.degree. C.,
215.degree. C., 216.degree. C., 217.degree. C., 218.degree. C.,
219.degree. C., 220.degree. C., 221.degree. C., 222.degree. C.,
223.degree. C., 224.degree. C., 225.degree. C., 226.degree. C.,
227.degree. C., 228.degree. C., 229.degree. C., 230.degree. C.,
231.degree. C., 232.degree. C., 233.degree. C., 234.degree. C.,
235.degree. C., 236.degree. C., 237.degree. C., 238.degree. C.,
239.degree. C., 240.degree. C., 241.degree. C., 242.degree. C.,
243.degree. C., 244.degree. C., 245.degree. C., 248.degree. C.,
250.degree. C., 252.degree. C., 255.degree. C., 258.degree. C.,
260.degree. C., 262.degree. C., 264.degree. C., 266.degree. C.,
268.degree. C., 270.degree. C., 272.degree. C., 274.degree. C.,
276.degree. C., 278.degree. C., 280.degree. C., 282.degree. C.,
284.degree. C., 286.degree. C., 288.degree. C., 290.degree. C.,
292.degree. C., 294.degree. C., 296.degree. C., 298.degree. C.,
300.degree. C., 302.degree. C., 304.degree. C., 306.degree. C.,
308.degree. C., 310.degree. C., 312.degree. C., 314.degree. C.,
316.degree. C., 318.degree. C., 320.degree. C., or any temperature
therebetween.
[0065] It is further contemplated that the temperature of
combustible liquid 12 may be heated in a step-wise fashion. This
step-wise heating may be done in a single receiving container 10
such that the same combustible liquid is heated to an initial
temperature and then heated to an increased temperature for
torrefying densified biomass 20. Using a single receiving container
reduces any costs that would be associated with transferring
densified biomass 20 between multiple receiving containers 10,
using multiple volumes of combustible liquid 12, and heating
multiple volumes of combustible liquid 12.
[0066] Combustible liquid 12 may be heated to an initial lower
temperature prior to loading with densified biomass 20. Once
densified biomass 20 is submerged within combustible liquid 12 at
the lower initial temperature for a certain period of time,
combustible liquid 12 may be heated to a higher temperature for
torrefaction. Such a step-wise heating of combustible liquid 12 and
densified biomass 20 may result in a more efficient and less costly
process, as the initial lower temperature may be used for heating
densified biomass 20 from its starting temperature to a higher
temperature and for releasing the majority of the moisture from
densified biomass 20; the higher temperature, on the other hand,
may be used for a shorter period of time for torrefying densified
biomass 20. Accordingly, less energy may be required as a higher
temperature would be required for a shorter period of time. By way
of example, combustible liquid 12 may be initially heated to a
temperature in a range of about 110.degree. C. to about 200.degree.
C., or any temperature therebetween, such as, but not limited to,
about 110.degree. C., 112.degree. C., 114.degree. C., 116.degree.
C., 118.degree. C., 120.degree. C., 122.degree. C., 124.degree. C.,
126.degree. C., 128.degree. C., 130.degree. C., 132.degree. C.,
134.degree. C., 136.degree. C., 138.degree. C., 140.degree. C.,
142.degree. C., 144.degree. C., 148.degree. C., 150.degree. C.,
151.degree. C., 152.degree. C., 153.degree. C., 154.degree. C.,
155.degree. C., 156.degree. C., 157.degree. C., 158.degree. C.,
159.degree. C., 160.degree. C., 161.degree. C., 162.degree. C.,
163.degree. C., 164.degree. C., 165.degree. C., 166.degree. C.,
167.degree. C., 168.degree. C., 169.degree. C., 170.degree. C.,
171.degree. C., 172.degree. C., 173.degree. C., 174.degree. C.,
175.degree. C., 176.degree. C., 177.degree. C., 178.degree. C.,
179.degree. C., 180.degree. C., 182.degree. C., 185.degree. C.,
188.degree. C., 190.degree. C., 192.degree. C., 195.degree. C.,
198.degree. C., 200.degree. C., or any temperature therebetween.
Densified biomass 20 may be submerged within the lower temperature
for about 2 minutes to about 30 minutes, or any amount of time
therebetween, such as 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5,
8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5,
15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5, 21,
21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5,
28, 28.5, 29, 29.5, 30 minutes, or any amount of time therebetween.
Following the initial period of the heat treatment, combustible
liquid 12, containing densified biomass 20 submerged therein, may
be further heated to a temperature of about 180.degree. C. to about
320.degree. C., or any temperature therebetween, such as, but not
limited to, about 181.degree. C., 182.degree. C., 183.degree. C.,
184.degree. C., 185.degree. C., 186.degree. C., 187.degree. C.,
188.degree. C., 189.degree. C., 190.degree. C., 191.degree. C.,
192.degree. C., 193.degree. C., 194.degree. C., 195.degree. C.,
196.degree. C., 197.degree. C., 198.degree. C., 199.degree. C.,
200.degree. C., 201.degree. C., 202.degree. C., 203.degree. C.,
204.degree. C., 205.degree. C., 206.degree. C., 207.degree. C.,
208.degree. C., 209.degree. C., 210.degree. C., 211.degree. C.,
212.degree. C., 213.degree. C., 214.degree. C., 215.degree. C.,
216.degree. C., 217.degree. C., 218.degree. C., 219.degree. C.,
220.degree. C., 221.degree. C., 222.degree. C., 223.degree. C.,
224.degree. C., 225.degree. C., 226.degree. C., 227.degree. C.,
228.degree. C., 229.degree. C., 230.degree. C., 231.degree. C.,
232.degree. C., 233.degree. C., 234.degree. C., 235.degree. C.,
236.degree. C., 237.degree. C., 238.degree. C., 239.degree. C.,
240.degree. C., 241.degree. C., 242.degree. C., 243.degree. C.,
244.degree. C., 245.degree. C., 248.degree. C., 250.degree. C.,
252.degree. C., 255.degree. C., 258.degree. C., 260.degree. C.,
262.degree. C., 264.degree. C., 266.degree. C., 268.degree. C.,
270.degree. C., 272.degree. C., 274.degree. C., 276.degree. C.,
278.degree. C., 280.degree. C., 282.degree. C., 284.degree. C.,
286.degree. C., 288.degree. C., 290.degree. C., 292.degree. C.,
294.degree. C., 296.degree. C., 298.degree. C., 300.degree. C.,
302.degree. C., 304.degree. C., 306.degree. C., 308.degree. C.,
310.degree. C., 312.degree. C., 314.degree. C., 316.degree. C.,
318.degree. C., 320.degree. C., or any temperature therebetween.
Densified biomass 20 may be torrefied in the higher temperature for
about 2 minutes to about 60 minutes, or any amount of time
therebetween, such as 2.5 minutes, 3 minutes, 3.5 minutes, 4
minutes, 4.5 minutes, 5 minutes, 5.5 minutes, 6 minutes, 6.5
minutes, 7 minutes, 7.5 minutes, 8 minutes, 8.5 minutes, 9 minutes,
9.5 minutes, 10 minutes, 10.5 minutes, 11 minutes, 11.5 minutes, 12
minutes, 12.5 minutes, 13 minutes, 13.5 minutes, 14 minutes, 14.5
minutes, 15 minutes, 15.5 minutes, 16 minutes, 16.5 minutes, 17
minutes, 17.5 minutes, 18 minutes, 18.5 minutes, 19 minutes, 19.5
minutes, 20 minutes, 20.5 minutes, 21 minutes, 21.5 minutes, 22
minutes, 22.5 minutes, 23 minutes, 23.5 minutes, 24 minutes, 24.5
minutes, 25 minutes, 25.5 minutes, 26 minutes, 26.5 minutes, 27
minutes, 27.5 minutes, 28 minutes, 28.5 minutes, 29 minutes, 29.5
minutes, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38
minutes, 40 minutes, 42 minutes, 44 minutes, 46 minutes, 48
minutes, 50 minutes, 52 minutes, 54 minutes, 56 minutes, 58
minutes, 60 minutes, or any amount of time therebetween.
[0067] The present disclosure contemplates densified biomass
material 20 being loaded directly into receiving container 10.
Alternatively, densified biomass material 20 may be loaded into a
holder 22, which is then immersed within receiving container
10.
[0068] To allow direct contact of densified biomass material 20
with combustible liquid 12 when holder 22 is used in the exemplary
process, holder 22 may be any type of holder that can fit the
densified feedstock to be torrefied and fit within receiving
container 10 and that is porous to combustible liquid 12 in
receiving container 10, but not to the densified feedstock. As
such, holder 22 prevents densified biomass 20 or torrefied
densified biomass 30 contained in holder 22 from falling outside
holder 22, while allowing combustible liquid 12 to flow through
holder 22 to heat and torrefy densified biomass 20. For example,
without limitation, holder 22 may be a wire-strainer type basket or
wire mesh basket or other type of basket with perforations within
its outer walls. It is understood that holder 22 can withstand the
heat of combustible liquid 12 and can be heated to a temperature of
up to about 320.degree. C. for extended periods of time.
[0069] Given that densified biomass 20 is completely submerged
within combustible liquid 12, which is heated to a temperature in a
range of about 160.degree. C. to about 280.degree. C., or any
temperature therebetween, densified biomass 20 is heated up to a
temperature in a range of about 160.degree. C. to about 320.degree.
C., or any temperature therebetween, by completion of the
torrefaction process. By way of further example, the temperature of
torrefied densified biomass 30 at the end of the exemplary process
can vary in a range of between about 180.degree. C. to about
320.degree. C., or any temperature therebetween; between about
180.degree. C. to about 300.degree. C., or any temperature
therebetween; between about 200.degree. C. and about 320.degree.
C., or any temperature therebetween; between about 200.degree. C.
and about 310.degree. C., or any temperature therebetween; between
about 200.degree. C. and about 300.degree. C., or any temperature
therebetween; between about 200.degree. C. and about 290.degree.
C., or any temperature therebetween; between about 200.degree. C.
and about 280.degree. C., or any temperature therebetween; between
about 200.degree. C. and about 270.degree. C., or any temperature
therebetween; between about 200.degree. C. and about 260.degree.
C., or any temperature therebetween; between about 200.degree. C.
and about 250.degree. C., or any temperature therebetween; between
about 200.degree. C. and about 240.degree. C., or any temperature
therebetween; between about 220.degree. C. and about 300.degree.
C., or any temperature therebetween; between about 220.degree. C.
and about 290.degree. C., or any temperature therebetween; between
about 220.degree. C. and about 280.degree. C., or any temperature
therebetween; between about 220.degree. C. and about 270.degree.
C., or any temperature therebetween; between about 220.degree. C.
and about 260.degree. C., or any temperature therebetween; between
about 220.degree. C. and about 250.degree. C., or any temperature
therebetween; between about 220.degree. C. and about 240.degree.
C., or any temperature therebetween; or can be about 162.degree.
C., 165.degree. C., 168.degree. C., 170.degree. C., 172.degree. C.,
175.degree. C., 178.degree. C., 180.degree. C., 181.degree. C.,
182.degree. C., 183.degree. C., 184.degree. C., 185.degree. C.,
186.degree. C., 187.degree. C., 188.degree. C., 189.degree. C.,
190.degree. C., 191.degree. C., 192.degree. C., 193.degree. C.,
194.degree. C., 195.degree. C., 196.degree. C., 197.degree. C.,
198.degree. C., 199.degree. C., 200.degree. C., 201.degree. C.,
202.degree. C., 203.degree. C., 204.degree. C., 205.degree. C.,
206.degree. C., 207.degree. C., 208.degree. C., 209.degree. C.,
210.degree. C., 211.degree. C., 212.degree. C., 213.degree. C.,
214.degree. C., 215.degree. C., 216.degree. C., 217.degree. C.,
218.degree. C., 219.degree. C., 220.degree. C., 221.degree. C.,
222.degree. C., 223.degree. C., 224.degree. C., 225.degree. C.,
226.degree. C., 227.degree. C., 228.degree. C., 229.degree. C.,
230.degree. C., 231.degree. C., 232.degree. C., 233.degree. C.,
234.degree. C., 235.degree. C., 236.degree. C., 237.degree. C.,
238.degree. C., 239.degree. C., 240.degree. C., 241.degree. C.,
242.degree. C., 243.degree. C., 244.degree. C., 245.degree. C.,
248.degree. C., 250.degree. C., 252.degree. C., 255.degree. C.,
258.degree. C., 260.degree. C., 262.degree. C., 264.degree. C.,
266.degree. C., 268.degree. C., 270.degree. C., 272.degree. C.,
274.degree. C., 276.degree. C., 278.degree. C., 280.degree. C.,
282.degree. C., 284.degree. C., 286.degree. C., 288.degree. C.,
290.degree. C., 292.degree. C., 294.degree. C., 296.degree. C.,
298.degree. C., 300.degree. C., 302.degree. C., 304.degree. C.,
306.degree. C., 308.degree. C., 310.degree. C., 312.degree. C.,
314.degree. C., 316.degree. C., 318.degree. C., 320.degree. C., or
any temperature therebetween. One of skill in the art will
appreciate that the temperature of torrefied densified biomass 30
at the end of the torrefaction process, prior to removal from
receiving container 10, will depend on the starting raw material,
the time that densified biomass 20 is submerged within heated
combustible liquid 12, the type of combustible liquid 12 used, and
the temperature of combustible liquid 12.
[0070] During submersion of the densified biomass 20 within
combustible liquid 12 and during the torrefaction process,
densified biomass 20 absorbs combustible liquid 12 such that the
resulting torrefied densified biomass 30 retains some absorbed
combustible liquid 12. The amount of combustible liquid 12 absorbed
by the densified biomass 20 and retained in the post-torrefaction
densified biomass 30 depends upon several different factors
including, for example, the physico-chemical properties of the
starting feedstock, the density of the densified biomass 20, the
amount of starting feedstock, the submersion time of the densified
biomass 20 in the combustible liquid 12, the combustible liquid 12
used, and the temperature of the combustible liquid 12. As will be
illustrated and described further in Examples 4 and 5, the
absorption of combustible liquid 12 by densified biomass 20 does
not occur at a constant rate. Combustible liquid 12 is initially
absorbed at a higher rate compared to absorption rates occurring
later in the torrefaction process. For example, the rate of
absorption at the beginning of the torrefaction process may be
between about 9% to about 18% w/w combustible liquid per mass of
the input bone dry densified biomass, or any rate therebetween such
as, without limitation, about 10%, 11%, 12%, 13%, 14%, 15%, 16%,
17%, or any rate therebetween. Following the initial higher rate of
absorption of the combustible liquid 12, the absorption rate
decreases and remains at a fairly constant rate for a period of
time during the torrefaction process. This lower rate occurring
during the mid-portion of the torrefaction process may be between
about 6% to about 14% w/w combustible liquid per mass of the input
bone dry densified biomass, or any rate therebetween such as,
without limitation, about 7%, 8%, 9%, 10%, 11%, 12%, 13%, or any
rate therebetween. It was discovered that if densified biomass 20
is submersed in combustible liquid 12 for longer periods of time,
rate of absorption of the combustible liquid 12 by the densified
biomass 20 decreases substantially. For example, the rate of
absorption during later periods of the torrefaction process may be
between about 2% to about 10% w/w combustible liquid per mass of
the densified biomass of the initial rate of absorption, or any
rate therebetween such as, without limitation, about 3%, 4%, 5%,
6%, 7%, 8%, 9%, or any rate therebetween. The rate of absorption of
combustible liquid 12 by densified biomass 20 may also fall to a
negative rate if the densified biomass 20 is submersed within
combustible liquid 12 for an extensive period of time. It appears
that some of the combustible liquid 12 absorbed by the densified
biomass 20 during the earlier stages of the torrefaction process
may be released from torrefied densified biomass 30 as the
torrefaction process is maintained for increasingly extended
periods of time. As disclosed above, the time ranges during which
the rate of absorption occurs at higher rates, constant rates,
lower rates of absorption, or negative rates; i.e., loss of the
combustible liquid by torrefied densified biomass 20 will depend on
one or more of the temperature of the combustible liquid 12, the
physico-chemical properties of the starting feedstock, the amount
of starting feedstock, the combustible liquid 12, the type of
combustible liquid 12 used, and other factors. However, it is
apparent that the rate of absorption of combustible liquid 12 by
densified biomass 20 varies during the torrefaction process, such
that, the rate of absorption is initially higher, subsequently
diminishing over time and, eventually, potentially resulting in
loss of some combustible liquid 12 absorbed earlier in the process.
Based on these findings, the duration of the torrefaction process
may be varied to obtain torrefied densified biomass 30 with
different amounts of combustible liquid 12 absorbed therein.
[0071] The amount of time that densified biomass 20 is submerged
within combustible liquid 12 may vary depending on different
variables, such as for example, the properties of the starting
feedstock, including its size and initial temperature, the size of
receiving container 10, the amount of the starting feedstock for
torrefaction, the amount of combustible liquid 12, the type of
combustible liquid 12, and the physico-chemical properties of
torrefied densified biomass 30 that is desired, such as the mass,
amount of oil contained therein, carbon content, hydrophobic nature
and the heat energy value (BTU per pound or GJ/t). By way of
example, the submersion time of densified biomass 20 in combustible
liquid 12 may vary from about 2 minutes to about 120 minutes, or
any amount of time therebetween; such as for example, from about 2
minutes to about 110 minutes, or any amount of time therebetween;
from about 2 minutes to about 100 minutes, or any amount of time
therebetween; from about 2 minutes to about 90 minutes, or any
amount of time therebetween; from about 2 minutes to about 80
minutes, or any amount of time therebetween; from about 2 minutes
to about 75 minutes, or any amount of time therebetween; from about
2 minutes to about 70 minutes, or any amount of time therebetween;
from about 2 minutes to about 65 minutes, or any amount of time
therebetween; from about 2 minutes to about 60 minutes, or any
amount of time therebetween; from about 2 minutes to about 55
minutes, or any amount of time therebetween; from about 2 minutes
to about 50 minutes, or any amount of time therebetween; from about
2 minutes to about 45 minutes, or any amount of time therebetween;
from about 2 minutes to about 40 minutes, or any amount of time
therebetween; from about 2 minutes to about 35 minutes, or any
amount of time therebetween; from about 2 minutes to about 30
minutes, or any amount of time therebetween; from about 2 minutes
to about 25 minutes, or any amount of time therebetween; from about
2 minutes to about 20 minutes, or any amount of time therebetween;
from about 5 minutes to about 60 minutes, or any amount of time
therebetween; from about 5 minutes to about 55 minutes, or any
amount of time therebetween; from about 5 minutes to about 50
minutes, or any amount of time therebetween; from about 5 minutes
to about 45 minutes, or any amount of time therebetween; from about
5 minutes to about 40 minutes, or any amount of time therebetween;
from about 5 minutes to about 35 minutes, or any amount of time
therebetween; from about 5 minutes to about 30 minutes, or any
amount of time therebetween; from about 5 minutes to about 25
minutes, or any amount of time therebetween; from about 5 minutes
to about 20 minutes, or any amount of time therebetween; from about
5 minutes to about 15 minutes, or any amount of time therebetween;
or about 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes,
4.5 minutes, 5 minutes, 5.5 minutes, 6 minutes, 6.5 minutes, 7
minutes, 7.5 minutes, 8 minutes, 8.5 minutes, 9 minutes, 9.5
minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14
minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19
minutes, 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24
minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29
minutes, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38
minutes, 40 minutes, 42 minutes, 44 minutes, 46 minutes, 48
minutes, 50 minutes, 52 minutes, 54 minutes, 56 minutes, 58
minutes, 60 minutes, or any amount of time therebetween.
[0072] Following submersion of densified biomass 20 in combustible
liquid 12 for the time desired, torrefied densified biomass 30 is
retrieved from receiving container 10. If densified biomass 20 is
directly loaded into receiving container 10, any type of utensil
may be used to retrieve torrefied densified biomass 30 from
receiving container 10. Preferably, the utensil used will limit the
amount of combustible liquid 12 that is removed with torrefied
densified biomass 30, as the present process contemplates reuse of
the combustible liquid 12. By way of example, the utensil may be a
perforated-type of utensil, such as, without limitation, a slotted
spoon, or may be a pair of forceps, tweezers, tongs, or the like.
If holder 22 is used to load densified biomass 20 into receiving
container 10, then holder 22, along with torrefied densified
biomass 30 contained therein, is removed from receiving container
10.
[0073] To minimize the amount of combustible liquid 12 that is
removed along with torrefied densified biomass 30, and thereby, be
able to reuse as much combustible liquid 12 as possible, torrefied
densified biomass 30, or holder 22 containing torrefied densified
biomass 30, may be held above receiving container 10 for about 15
seconds to about 150 seconds, or any time therebetween, to drain
torrefied densified biomass 30 of combustible liquid 12 and drip
combustible liquid 12 into receiving container 10 for reuse. For
example, without limitation, torrefied densified biomass 30, or
holder 22, may be held above receiving container 10 for about 15
seconds, 16 seconds, 17 seconds, 18 seconds, 19 seconds, 20
seconds, 21 seconds, 22 seconds, 23 seconds, 24 seconds, 25
seconds, 26 seconds, 27 seconds, 28 seconds, 29 seconds, 30
seconds, 31 seconds, 32 seconds, 33 seconds, 34 seconds, 35
seconds, 36 seconds, 37 seconds, 38 seconds, 39 seconds, 40
seconds, 41 seconds, 42 seconds, 43 seconds, 44 seconds, 45
seconds, 48 seconds, 50 seconds, 52 seconds, 55 seconds, 58
seconds, 60 seconds, 65 seconds, 70 seconds, 75 seconds, 80
seconds, 85 seconds, 90 seconds, 95 seconds, 100 seconds, 105
seconds, 110 seconds, 115 seconds, 120 seconds, 125 seconds, 130
seconds, 135 seconds, 140 seconds, 145 seconds, 150 seconds, or any
amount of time therebetween. If time permits, a skilled person will
appreciate that torrefied densified biomass 30, or holder 22, may
be held above receiving container 10 for longer periods of time to
maximize the amount combustible liquid 12 retained in receiving
container 10. Accordingly, the exemplary process described herein
maximizes retention of oil or combustible liquid 12 in receiving
container 10, rather than absorption into the torrefied densified
biomass, to reduce costs of replenishing the oil for torrefaction
with each cycle.
[0074] The exemplary process further provides a cooling step,
wherein torrefied densified biomass 30 is placed in a cooling
system 32 to cool torrefied densified biomass 30 to near-ambient
temperatures until it can be safely handled for packaging, storing,
use, or transportation. Cooling system 32 may be, for example, a
cold water bath with the water at a sufficiently cold temperature
to cool torrefied densified biomass 30 to a near-ambient
temperature. For example, without limitation, the cold water bath
may have water at a temperature of about 0.degree. C. to about
100.degree. C., or any temperature therebetween, such as, without
limitation, about 0.degree. C., 2.degree. C., 4.degree. C.,
6.degree. C., 8.degree. C., 10.degree. C., 12.degree. C.,
14.degree. C., 16.degree. C., 18.degree. C., 20.degree. C.,
22.degree. C., 24.degree. C., 26.degree. C., 28.degree. C.,
30.degree. C., 32.degree. C., 34.degree. C., 36.degree. C.,
38.degree. C., 40.degree. C., 42.degree. C., 44.degree. C.,
46.degree. C., 48.degree. C., 50.degree. C., 52.degree. C.,
54.degree. C., 56.degree. C., 58.degree. C., 60.degree. C.,
62.degree. C., 64.degree. C., 68.degree. C., 70.degree. C.,
72.degree. C., 74.degree. C., 76.degree. C., 78.degree. C.,
80.degree. C., 82.degree. C., 84.degree. C., 86.degree. C.,
88.degree. C., 90.degree. C., 92.degree. C., 94.degree. C.,
96.degree. C., 98.degree. C., 100.degree. C., or any temperature
therebetween. Torrefied densified biomass 30 may be immersed in the
cold water bath for about 0.5 to about 20 minutes, or any amount of
time therebetween, such as, without limitation, 0.5 minutes, 1
minutes, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7
minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes,
13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18
minutes, 19 minutes, 20 minutes, or any amount of time
therebetween. It is understood that torrefied densified biomass 30
may be left in the cold water bath for longer periods of time, and
the amount of time will vary depending on a number of factors, such
as, the size of torrefied densified biomass 30, the size and
temperature of the cold water bath, the starting temperature of
torrefied densified biomass 30 (i.e., its temperature at the point
it is retrieved from receiving container 10), and the desired
temperature of the torrefied densified biomass 30 for handling. The
torrefaction process produces a hydrophobic torrefied biomass.
Accordingly, cooling torrefied densified biomass 30 in water does
not generally result in significant absorption of water or an
increase in weight of the torrefied densified biomass 30. However,
the amount of water absorbed by the torrefied densified biomass 30
is relative to the amount of time that densified biomass 20 is
retained in hot combustible liquid 12 and the temperature of
combustible liquid 12. It is further contemplated that torrefied
densified biomass may also be cooled in a step-wise fashion, such
that an initial cold water bath with water at a temperature between
about 50.degree. C. to about 100.degree. C., or any temperature
therebetween, is used, followed by a cold water bath at a
temperature between about 0.degree. C. to about 50.degree. C., or
any temperature therebetween. This step-wise cooling may increase
the efficiency of the cooling step and thereby reduce costs and
increase throughput.
[0075] Torrefied densified biomass 30 may be placed directly into
cooling system 32 without holder 22, or holder 22 containing
torrefied densified biomass 30 therein may be placed into cooling
system 32. Accordingly, torrefied densified biomass 30 may be
extracted from the cold water bath in a manner similar to how it is
retrieved from receiving container 10, as described above. The use
of a cooling system 32, such as a cold water bath, does not require
significant energy or resources to operate, thus providing a
further cost-savings and efficiency. Furthermore, collection of any
steam expelled during the cooling process may also be used in other
stages of the process, as described in more detail below.
[0076] Further, as mentioned above, the amount of combustible
liquid 12 absorbed and retained within torrefied densified biomass
30 may be varied depending on various factors, including the
duration of the torrefaction process and submersion of densified
biomass 20 within combustible liquid 12, the temperature of the
combustible liquid 12, the properties of the starting feedstock,
the amount of the starting feedstock, and the type of combustible
liquid 12 used, amongst other factors. Consequently, the heat
energy value of torrefied densified biomass 30 may also be tailored
by adjusting the variables, such as the duration of the
torrefaction process and submersion of densified biomass 20 within
combustible liquid 12, the temperature of the combustible liquid
12, the properties of the starting feedstock, the amount of the
starting feedstock, and the combustible liquid 12 used, amongst
other factors.
[0077] Another exemplary process of the present disclosure is shown
in FIG. 2. In this embodiment, the starting raw biomass material is
densified such that no densification step is required prior to
immersion in combustible liquid 12. Densified biomass 20 can be any
biomass material that is readily commercially available as a
densified biomass product. Other than the initial starting
material, the remaining steps of this embodiment are the same as
those described in relation to FIG. 1.
[0078] As shown in FIGS. 1 and 2, a gas collection and condenser
system 40 comprising a plurality of pipes may be used for
connecting to receiving container 10 and cooling system 32. System
40 may comprise a series of inlets and outlets, with an inlet
disposed in each of receiving container 10 and cooling system 32
above the liquid level of combustible liquid 12 and the cooling
water in cooling system 32, respectively. The inlet disposed in
receiving container 10 is for collecting VOCs and steam, and the
inlet disposed in cooling system 32 is for collecting steam upon
cooling of the torrefied densified biomass. An inlet may also be
disposed in densifier 5 or dryer 7 (or a combined dryer/densifier)
to capture any steam that is expelled during the densification and
drying processes. The mixture of VOCs and steam may be further
processed and condensed in system 40. The mixture may be separated
into bio-liquids and gases that contain CO, CO.sub.2 and perhaps
also H.sub.2, CH.sub.4 and other trace volatiles. The gases may be
burnt to help heat the combustible liquid 12 in receiving container
10 or to provide energy for dryer 7 or densifier 5 (or a combined
dryer/densifier). If the gases are used in the exemplary processes,
outlets of system 40 will be disposed within the heat sources for
heating combustible liquid 12 and within the dryer 7 and densifier
5 (or a combined dryer/densifier) to assist in operating these
machines. Alternatively, the gases may be used or sold separately
as feedstock for other chemical synthesis processes. The
bio-liquids obtained from the non-volatile vapors and steam may be
reused in cooling system 32 or potentially in a steam generator or
boiler for heating combustible liquid 12. The present disclosure,
therefore, provides for a heat exchange system that results in a
more energy-efficient process.
[0079] It is further contemplated that the exemplary processes
described herein may be continuous, semi-continuous or batch
processes. With a continuous, semi-continuous or batch process, the
various steps of the process may be connected by a conveyor-type
system or other type of system to allow continuous transporting of
densified biomass 20 or holder 22 containing densified biomass 20
therein through the present processes as described herein. The
present disclosure therefore contemplates a system for carrying out
the exemplary torrefaction processes disclosed herein. In such a
system, a conveyor or other type of transport system may be used to
carry the raw biomass material, whether densified to begin with or
not, through the processes described in FIGS. 1 and 2. Accordingly,
the raw biomass material 2 is brought from the densifier 5/dryer 7
or receiving container 10 through the process to the cooling system
32, where the torrefied densified biomass 30 is retrieved and
available for handling, transport, use, shipping, etc. Any type of
continuous system, semi-continuous system or batch system
contemplated herein is a straight-line, simple to design, easily
operatable and efficient system, with limited complexity and
engineering required.
[0080] The exemplary processes described herein may further
comprise a step of cleaning the torrefied densified biomass 30.
This step of cleaning may comprise a screening process, wherein a
screening device is used to separate fines and any other waste
particles from torrefied densified biomass 30. Alternatively, this
step of cleaning may comprise a washing step, wherein torrefied
densified biomass 30 is washed in a water bath to remove residual
combustible oil adhering to the outer surface of the torrefied
densified biomass 30. The cleaning of the torrefied densified
biomass 30 may also comprise both a screening step and a washing
step.
[0081] Another embodiment of the present disclosure relates to an
exemplary process 100 illustrated in FIG. 3 wherein a selected
biomass or biosolids feedstock is delivered to a pellet press or
briquetter 105 wherein the feedstock is densified and extruded as
pellets or pressed into briquettes (i.e., densified biomass 20)
which are transferred by a pellet feed conveyer 110 into a
torrefusion reactor 115. The supply of the selected biomass or
biosolids feedstock to pellet press or briquetter 105 may be
continuous, semi-continuous or in batches, thereby resulting in a
continuous, semi-continuous or batch throughput process 100. The
torrefusion reactor 115 contains a volume of heated combustible oil
12 wherein the pellets 20 are submerged and torrefied for a
selected period of time. The combustible oil 12 contained in the
torrefusion reactor 115, is maintained at a temperature from the
range of about 160.degree. C. to about 320.degree. C. The
torrefusion reactor 115 has components that controllably maintain
the pellets 20 submerged in the heated combustible oil 12 while
controllably conveying the submerged pellets 20 from the input end
to the output end of the torrefusion reactor 115. The submerged
pellets 20 are torrefied during their transport from the input end
to the output end of the torrefusion reactor 115 via conveyor 110
(or any other suitable conveyor belt that allows continuous or
semi-continuous transport of the pellets through the process 100).
The duration of time for transport of the submerged pellets 20 from
the input end to the output end of the torrefusion reactor 115 can
be controllably varied from about 2 minutes to about 120 minutes
(or longer if so desired). After leaving the output end of the
torrefusion reactor 115, the torrefied pellets are conveyed on
conveyor 110 (or any other suitable conveyor belt that allows
continuous or semi-continuous transport of the pellets through the
process 100) to a cooler 120 from which they are conveyed into and
through a screening device 125 which separates fines from the
torrefied pellets. Finally, the screened torrefied pellets are
conveyed into a finished product bin 130 via conveyor 110 (or any
other suitable conveyor belt that allows continuous or
semi-continuous transport of the pellets through the process
100).
[0082] Heat and gases produced during torrefaction of the pellets
in the torrefusion reactor 115 are collected in a torgas collection
hood 160 under a vacuum force created by torgas fan 170 which
conveys the heat and torrefaction gases to the torgas burner 145.
The torgas burner 145 combines and combusts the torrefaction gases
to produce heated air which is then conveyed to the hot side of an
air-to-oil heat exchanger 150. The torgas burner 145 and thermal
energy from the external burner is combined prior to the heat
exchanger 150. The combustible oil contained within the torrefusion
reactor 115 is maintained at a selected temperature by constant
circulation by an oil pump 152 through an oil filter 154 and into
the cool side of the air-to-oil heat exchanger 150 wherein it is
heated by the heated air incoming from the torgas burner 145. The
heated combustible oil is then conveyed back into the torrefusion
reactor 115. The air-to-oil heat exchanger 150 is vented 158 to the
atmosphere. Optionally, the screened fines 135 may also be conveyed
to a burner 140 for production of thermal energy, and the thermal
energy then routed to a torgas burner 145.
[0083] Another embodiment of the present disclosure relates to an
exemplary process 200 illustrated in FIG. 4 wherein a selected
biomass or biosolids feedstock is delivered to a pellet press or
briquetter 202 wherein the feedstock is densified and extruded as
pellets or pressed into briquettes which are transferred by a
pellet feed conveyer 205 into a torrefusion reactor 210. The supply
of the selected biomass or biosolids feedstock to pellet press or
briquetter 202 may be continuous, semi-continuous or in batches,
thereby resulting in a continuous, semi-continuous or batch
throughput process 200. The torrefusion reactor 210 contains a
volume of heated combustible oil wherein the pellets are submerged
and torrefied for a selected period of time. The combustible oil
contained in the torrefusion reactor 210, is maintained at a
temperature from the range of about 160.degree. C. to about
320.degree. C. The torrefusion reactor 210 has components that
controllably maintain the pellets submerged in the heated
combustible oil while controllably conveying the submerged pellets
from the input end to the output end of the torrefusion reactor 210
via conveyer 205 or another conveyor belt that allows continuous or
semi-continuous transport of the pellets through the process 200.
The submerged pellets are torrefied during their transport from the
input end to the output end of the torrefusion reactor 210. The
duration of time for transport of the submerged pellets from the
input end to the output end of the torrefusion reactor 210 can be
controllably varied from about 2 minutes to about 120 minutes (or
longer if so desired). After leaving the output end of the
torrefusion reactor 210, the torrefied pellets are conveyed by
conveyor 205 (or any other suitable conveyor belt that allows
continuous or semi-continuous transport of the pellets through the
process 200) into a water bath cooler 215 which receives a constant
supply of fresh water 212. Residual combustible oil adhering to the
surface of the torrefied pellets conveyed from the torrefusion
reactor 210 is washed away from the torrefied pellets into the wash
water which is then separated from the washed torrefied pellets.
The washed torrefied pellets are conveyed into a finished product
bin 220 by conveyor 205 (or any other suitable conveyor belt that
allows continuous or semi-continuous transport of the pellets
through the process 200).
[0084] Heat and gases produced during torrefaction of the pellets
in the torrefusion reactor 210 are collected in a torgas collection
hood 250 under a vacuum force created by a torgas fan 255 which
conveys the heat and torrefaction gases to a torgas burner 260. The
torgas burner 260 combines and combusts the torrefaction gases with
a supply of thermal energy from an external burner 262 to produce
heated air which is then conveyed to the hot side of an air-to-oil
heat exchanger 235. The combustible oil contained within the
torrefusion reactor 210 is maintained at a selected temperature by
constant circulation by an oil pump 225 through an oil filter 230
and into the cool side of the air-to-oil heat exchanger 235 wherein
it is heated by the heated air incoming from the torgas burner 260.
The heated combustible oil is then conveyed back into the
torrefusion reactor 210. The air-to-oil heat exchanger 235 is
vented 237 to the atmosphere.
[0085] Either fresh water or the wash water from the water bath
cooler 215 is optionally routed to equipment 275 that can receive
an incoming biomass feedstock from a hopper referred to in FIG. 4
as a "raw salty hog" 270, that may need desalinization processing.
Such biomass feedstocks are exemplified by hog fuel wastestreams
produced from processing of harvested logs that have been
transported on and/or stored on saltwater waterways, which may
require desalinization. The wash water is blended with the biomass
feedstock in desalting and dewatering equipment 275. The salinized
wash water recovered from the desalting and dewatering equipment
may optionally be disposed of as an effluent 272, while the
desalted and dewatered biomass feedstock is conveyed to the pellet
press 202 for densification and extrusion as pellets.
[0086] Representative illustrations of a small scale torrefusion
reactor for use as torrefusion reactor 115, 210 are shown in FIGS.
5(A), 5(B), 6(A) and 6(B). Torrefusion reactor 115, 210 may
comprise a mechanism for continuously or semi-continuously
conveying densified biomass 20 through the reactor 115, 210, or for
conveying densified biomass 20 in batches through the reactor 115,
210, such as by way of conveyor 110, 205 (or any other suitable
conveyor belt that allows continuous or semi-continuous transport
of the densified biomass 20 through process 100, 200). Conveyor
110, 205 may be hand-operated, electronically-operated,
battery-operated, solar-operated, or otherwise powered to convey
densified biomass 20 into and through the torrefusion reactor 115,
210 and torrefied densified biomass 30 out of the torrefusion
reaction 115, 210. As shown in FIGS. 5(B), 6(A) and 6(B), the
torrefusion reaction may comprise holder 22 or other type of intake
hopper/feeder that operates as a densified biomass/biosolids
metering bin and comprises a notch, slit, hole, space or any other
type of opening 280 at the point of contact with conveyor 110, 205
between the bottom of holder 22 and conveyor 110, 205, such that
the densified biomass 20 may be gravity fed from the holder 22 onto
the moving conveyor 110, 205 as the conveyor moves. The throughput
of the densified biomass 20 onto conveyer 110, 205 and through
process 100, 200 may be controlled by adjusting the size of the
notch, slit, hole, space or other type of opening 280 in or at the
bottom of holder 22 and/or by adjusting the amount, size, weight
and thickness of the bed of densified biomass 20 placed in holder
22. The direction of rotation of conveyor 110, 205 is shown in FIG.
6(B). Arrow (A) represents the direction of rotation of conveyor
110, 205 to carry the densified biomass 20 into the combustible
liquid for a certain period of time and then conveying the
torrefied densified biomass 30 out of the combustible liquid. Arrow
(B), shown in shadow, indicates that conveyor 110, 205 may be an
endless conveyor belt that can continuously or semi-continuously
move densified biomass 20 through the torrefaction processes
disclosed herein. It will be understand that in a full-scale,
operational throughput process, this conveyor 110, 205 may continue
to convey the torrefied densified biomass 30 into water bath cooler
215. An exemplary size for a small scale torrefusion reactor 115,
210 is shown in Table A below.
TABLE-US-00001 TABLE A Torrefusion Reactor Size Reactor Length
(feet) 36 Reactor Width (feet) 5 Conveyor Thickness (inches) 4
Retention/Submersion time (minutes) 15 Bulk Density (lbs/ft.sup.3)
40 Fill Factor (%) 100% Mass of Conveyor Mat (lbs/ft.sup.3) 2,400
Mass of Conveyor Mat (MT) 1.09 Conveyor Cycles per Hour 4 Input per
Hour (MT) 4.355 Output per Hour @ 80% (MT) 3.484 Operating Hours
per Day 24.00 Operating Hours per Week 7.00 Operating Weeks per
Year 50.00 Uptime (%) 80 Total Capacity (input) (MT/annum) 29,262
Total Capacity (output) (MT/annum) 23,410
[0087] Torrefied densified biomass 30 produced by the processes
described herein comprises about 2% to about 25% w/w combustible
liquid following torrefaction (i.e., torrefied densified biomass 30
absorbs about 2% to about 25% w/w combustible liquid during the
process), or any amount therebetween. For example, without
limitation, the amount of combustible liquid 12 absorbed and
retained within torrefied densified biomass 30 may be about 2% to
about 25% w/w combustible liquid, or any amount therebetween; about
2% to about 24% w/w combustible liquid, or any amount therebetween;
about 2% to about 23% w/w combustible liquid, or any amount
therebetween; about 2% to about 22% w/w combustible liquid, or any
amount therebetween; about 2% to about 21% w/w combustible liquid,
or any amount therebetween; about 2% to about 20% w/w combustible
liquid, or any amount therebetween; about 2% to about 19% w/w
combustible liquid, or any amount therebetween; about 2% to about
18% w/w combustible liquid, or any amount therebetween; about 2% to
about 17% w/w combustible liquid, or any amount therebetween; such
as, for example, 3% w/w combustible liquid, 4% w/w combustible
liquid, 5% w/w combustible liquid, 6% w/w combustible liquid, 7%
w/w combustible liquid, 8% w/w combustible liquid, 9% w/w
combustible liquid, 10% w/w combustible liquid, 11% w/w combustible
liquid, 12% w/w combustible liquid, 13% w/w combustible liquid, 14%
w/w combustible liquid, 15% w/w combustible liquid, 16% w/w
combustible liquid, or any amount therebetween.
[0088] Torrefied densified biomass 30 produced by the processes of
the present disclosure may further have a heat energy value of
about 6,000 BTU per pound on a bone dry basis to about 13,000 BTU
per pound on a bone dry basis, or any heat energy value
therebetween, for example, from about 6,000 BTU per pound on a bone
dry basis to about 12,000 BTU per pound on a bone dry basis, or any
heat energy value therebetween; from about 6,000 BTU per pound on a
bone dry basis to about 11,000 BTU per pound on a bone dry basis,
or any heat energy value therebetween; from about 6,000 BTU per
pound on a bone dry basis to about 10,000 BTU per pound on a bone
dry basis, or any heat energy value therebetween; from about 6,000
BTU per pound on a bone dry basis to about 9,000 BTU per pound on a
bone dry basis, or any heat energy value therebetween; or from
about 9,000 BTU per pound on a bone dry basis to about 13,000 BTU
per pound on a bone dry basis, or any heat energy value
therebetween; such as, for example, about 9,500 BTU per pound on a
bone dry basis; about 10,000 BTU per pound on a bone dry basis;
about 10,500 BTU per pound on a bone dry basis; about 11,000 BTU
per pound on a bone dry basis; about 11,500 BTU per pound on a bone
dry basis; about 12,000 BTU per pound on a bone dry basis; about
12,500 BTU per pound on a bone dry basis; about 13,000 BTU per
pound on a bone dry basis, or any heat energy value therebetween.
Alternatively, torrefied densified biomass 30 may comprise a heat
energy value of about 22 GJ/t on a bone dry basis to about 27 GJ/t
on a bone dry basis, or any heat energy value therebetween, for
example, from about 22 GJ/t on a bone dry basis to about 26.5 GJ/t
on a bone dry basis or any heat energy value therebetween; from
about 22 GJ/t on a bone dry basis to about 26 GJ/t on a bone dry
basis or any heat energy value therebetween; from about 22 GJ/t on
a bone dry basis to about 26 GJ/t on a bone dry basis or any heat
energy value therebetween; from about 22 GJ/t on a bone dry basis
to about 25 GJ/t on a bone dry basis or any heat energy value
therebetween; from about 22 GJ/t on a bone dry basis to about 24
GJ/t on a bone dry basis or any heat energy value therebetween; or
from about 22 GJ/t on a bone dry basis to about 23 GJ/t on a bone
dry basis, or any heat energy value therebetween.
[0089] The torrefied densified biomass 30 produced by the processes
disclosed herein may also have a carbon content of about 50 carbon
% on a bone dry basis to about 65 carbon % on a bone dry basis, or
any amount therebetween. For example, without limitation, the
carbon content of the torrefied densified biomass 30 may be about
51 carbon % on a bone dry basis, 52 carbon % on a bone dry basis,
53 carbon % on a bone dry basis, 54 carbon % on a bone dry basis,
55 carbon % on a bone dry basis, 56 carbon % on a bone dry basis,
57 carbon % on a bone dry basis, 58 carbon % on a bone dry basis,
59 carbon % on a bone dry basis, 60 carbon % on a bone dry basis,
61 carbon % on a bone dry basis, 62 carbon % on a bone dry basis,
63 carbon % on a bone dry basis, 64 carbon % on a bone dry basis,
65 carbon % on a bone dry basis, or any amount therebetween.
[0090] As disclosed above, the amount of combustible liquid 12
absorbed and retained within torrefied densified biomass 30 may
vary depending on one or more factors exemplified by the duration
of the torrefaction process, submersion of densified biomass 20
within the combustible liquid 12, the temperature of the
combustible liquid 12, the physico-chemical properties of the
starting feedstock, the amount of the starting feedstock, and the
type of combustible liquid 12 used, amongst other factors.
Consequently, the heat energy value of torrefied densified biomass
30 and any other physico-chemical property of the torrefied
densified biomass 30, such as the carbon content, or the
hydrophobic nature of the torrefied densified biomass 30, may also
be tailored by adjusting the one or more variables such as the
duration of the torrefaction process, submersion of densified
biomass 20 within combustible liquid 12, the temperature of the
combustible liquid 12, the properties of the starting feedstock,
the amount of the starting feedstock, and the type of combustible
liquid 12 used, amongst other factors.
EXAMPLES
[0091] The following examples are provided to enable a better
understanding of the disclosure described herein.
Example 1
Materials and Methods
[0092] In this example, a small test unit was designed for testing
purposes. The test unit consisted of: a small container for holding
a combustible liquid, such as vegetable oil; a gas burner, on which
to place the small container; and a wire basket with a contour of
the small container, such that the wire basket fit within the inner
walls of the small container. In addition, a small scale capable of
measuring up to 10 kgs in 0.001 kg increments and a thermocouple
and temperature gauge was used for weight and temperature
calculations, respectively.
[0093] For this example, 10 kilograms of densified softwood pellets
made from a blend of spruce, pine and fir were tested. The 10
kilograms were divided into 1 kilogram samples (using the small
scale for measuring), and 1 sample was set aside for testing
purposes. As an initial step, the small container was placed on a
scale and the net weight of the empty small container was measured.
Vegetable oil was then poured into the small container and the
total weight of the small container plus vegetable oil was
measured, thereby providing a net weight for the vegetable oil. One
kilogram of unheated oil was set aside for additional
measurements.
[0094] Once the measurements of the vegetable oil were complete,
the gas burner was turned on to a temperature of about 270.degree.
C., and the temperature of the vegetable oil in the small container
was monitored using the thermocouple and temperature gauge. After
the temperature of the vegetable oil was stabilized at about
260.degree. C. to about 270.degree. C., a 1-Kg sample of densified
wood pellets was loaded into the wire strainer basket and submerged
in the heated vegetable oil in the small container for about 5
minutes. The wire strainer basket with the densified wood pellets
contained therein was then removed from the vegetable oil in the
small container, and allowed to drain and drip dry over the small
container for 5 minutes. The torrefied densified biomass was
retrieved from the wire strainer basket and its weight measured,
without submersing in a cold water, to avoid any water absorption
by the torrefied densified biomass and contamination of the
results. The net weight loss or gain of the sample was then
calculated by comparing to the starting weight of the densified
wood pellets, on a dry basis. The net weight of the used oil was
also measured by measuring the small container containing the used
oil and subtracting the weight of the small container. Oil loss by
absorption and mass loss of pellets was calculated. This process
was repeated another 8 times, each with a 1 kilogram sample of
densified wood pellets. The total weight of the small container
containing the oil was measured prior to each experiment. One
kilogram of the used vegetable oil in the small container was
collected for additional testing purposes.
[0095] The resulting torrefied densified biomass from all 9 test
experiments were collected and mixed together to form a sample
batch. One kilogram of the sample batch was collected for
testing.
Results:
[0096] The results from two sample batches prepared according to
the process described for Example 1 are shown in Table 1. The test
results indicated that with about 5 minutes in a vegetable oil
heated to about 260.degree. C. to about 270.degree. C., densified
wood pellets increased in weight by an average of about 10% and
increased in BTU value by an average of 15%. In addition, the
torrefied wood pellets were found to be hydrophobic and to have
increased grindability (i.e., high Hardgrove Grindability Index) as
compared to untorrefied wood pellets. "Hardgrove Grindability
Index" ("HGI") is a measure for grindability of coal. Grindability
is indicated using the unit .degree. H, for example, "40.degree. H"
or "55.degree. H." A higher HGI value indicates a more easily
pulverized or more grindable product.
[0097] As shown in Table 1 below, the lower heating value (LHV) of
two sample batches of torrefied pellets obtained from the process
were 23.11 and 22.76 GJ/ton, respectively. This represents an
increase in LHV of approximately 14.8% for sample 1 and
approximately 16.1% for sample 2. Those skilled in the art will
know that an average LHV for wood pellet fuel ranges from a low of
18.14 GJ/ton to a high of 19.72 GJ/ton, making torrefied wood
pellets of the disclosed process to be approximately 17.5% higher
in heat value compared to good quality biofuel.
TABLE-US-00002 TABLE 1 Starting Densified Wood Torrefied Wood
Pellet Torrefied Wood Pellet Pellet #1 #1 #2 As Received As
Received As Received Measurements Basis Dry Basis Basis Dry Basis
Basis Dry Basis Weight 1 kg 1 kg 1 kg % Moisture* 7.00 0 2.78 0
0.59 0 Calorific Value (Gross) Btu/lb 8336 8963 9786 10066 9934
9993 Kcal/kg 4631 4979 5437 5592 5519 5552 GJ/ton 19.39 20.85 22.76
23.41 23.11 23.24 % Carbon 55.46 55.79 % Hydrogen 6.58 6.62
(excludes H in 36.92 moisture) % Nitrogen 0.09 0.09 % Sulphur 0.02
0.02 % Ash 0.56 0.56 % Oxygen 36.70 36.92 % Hydrogen 6.65 --
(includes H in moisture) *"% Moisture" for the "Torrefied Wood
Pellets" refers to the amount of water in the torrefied wood
pellets immediately after the torrefaction process (i.e., after
drip drying for 5 minutes). "Starting Densified Wood Pellet" is the
sample that was initially set aside for testing purposes.
Example 2
Materials and Methods
[0098] In this example, a coastal hemlock briquette was quartered
and each quarter was used for testing. Three of the quarters were
used in the torrefaction process and one quarter was set aside. The
initial weight of the quartered briquettes used in the torrefaction
process is set out in Table 2 below.
[0099] The small test unit, as described above for Example 1, was
used in this example. As an initial step, the small container was
placed on a scale and the net weight of the empty small container
was measured. Vegetable oil was then poured into the small
container and the total weight of the small container plus
vegetable oil was measured, thereby providing a net weight for the
vegetable oil. One kilogram of unheated oil was set aside for
additional measurements.
[0100] After the measurements of the vegetable oil were complete,
the gas burner was turned on to a temperature of about 260.degree.
C., and the temperature of the vegetable oil in the small container
was monitored. After the temperature of the vegetable oil was
stabilized at about 260.degree. C., a quarter briquette sample was
loaded into the wire strainer basket and submerged in the heated
vegetable oil in the deep fryer for about 7.5 minutes. The wire
strainer basket with the quarter briquette sample contained therein
was then removed from the vegetable oil in the small container and
allowed to drain over the deep fryer for 5 minutes. The torrefied
densified biomass was then retrieved from the wire strainer basket
and its weight measured, without submersing in a cold water, to
avoid any water absorption by the torrefied densified biomass and
contamination of the results. The net weight loss or gain of the
sample was then calculated by comparing to the starting weight of
the densified wood pellets, on a dry basis. The net weight of the
used oil was also measured by measuring the small container
containing the used oil and subtracting the weight of the small
container. Oil loss by absorption and mass loss of pellets was
calculated. This process was then repeated another 2 times for the
other 2 quarter briquette samples, with the exception that 1
quarter briquette was torrefied for about 10 minutes, and the other
for about 15 minutes. The total weight of the small container
containing the oil was measured prior to each experiment. One
kilogram of the used vegetable oil in the small container was
collected for additional testing purposes. The resulting torrefied
densified biomass from each experiment was collected for
testing.
Results:
[0101] The results for Example 2 are shown in Table 2. The test
results indicated that all quarter briquette samples increased in
weight, on average, by about 10% as compared to the original weight
of the respective quarter briquette, representing the approximate
amount of oil absorbed by the samples. In addition, the torrefied
wood pellets were found to be hydrophobic and to have increased
grindability (i.e., high Hardgrove scale score) as compared to
untorrefied wood pellets.
TABLE-US-00003 TABLE 2 Quartered Briquettes Experiment Sample 1
Sample 2 Sample 3 Starting Weight (g) 139.85 140.85 149.60 Finished
Weight (g) 156.40 155.25 165.75 Net Increase in Weight (%) 10.58%
9.28% 9.74% Starting Temp. of Oil (.degree. C.) 222.00 269.00
266.00 Ending Temp. of Oil (.degree. C.) 266.00 270.00 267.00
Retention Time in Oil (mins) 15.00 7.50 10.00
Example 3
Materials and Methods
[0102] In this example, 2 1-Kg samples of densified softwood
pellets made from a blend of spruce, pine and fir were tested in
the small test unit described above in Example 1.
[0103] As an initial step, the small container was placed on a
scale and the net weight of the empty small container was measured.
Vegetable oil was then poured into the small container and the
total weight of the small container plus vegetable oil was
measured, thereby providing a net weight for the vegetable oil. One
kilogram of unheated oil was set aside for additional
measurements.
[0104] After the measurements of the vegetable oil were complete,
the gas burner was turned on to a temperature of about 250.degree.
C. to about 260.degree. C., and the temperature of the vegetable
oil in the small container was monitored. After the temperature of
the vegetable oil was stabilized at about 250.degree. C. to about
260.degree. C., a 1-kilogram sample of densified wood pellets was
loaded into the wire strainer basket and submerged in the heated
vegetable oil in the small container for about 20 minutes for the
first sample. The wire strainer basket with the densified wood
pellets contained therein was then removed from the vegetable oil
in the small container and allowed to drain over the deep fryer for
5 minutes. The torrefied densified biomass was then retrieved from
the wire strainer basket and its weight measured, without
submersing in a cold water bath, to avoid any water absorption by
the torrefied densified biomass and contamination of the results.
The net weight loss or gain of the sample was then calculated by
comparing to the starting weight of the densified wood pellets, on
a dry basis. The net weight of the used oil was also measured by
measuring the small container containing the used oil and
subtracting the weight of the small container. Oil loss by
absorption and mass loss of pellets was calculated.
[0105] After the above process, the second 1-kg sample was loaded
into the wire strainer basket and submerged in the heated vegetable
oil in the small container for about 30 minutes. The wire strainer
basket with the densified wood pellets contained therein was then
removed from the small container and allowed to drain over the deep
fryer for 5 minutes. The net weight loss or gain of the sample was
then calculated by comparing to the starting weight of the
densified wood pellets, on a dry basis. The net weight of the used
oil was also measured by measuring the small container containing
the used oil and subtracting the weight of the small container. Oil
loss by absorption and mass loss of pellets was calculated. One
kilogram of the used vegetable oil in the deep fryer was collected
for additional testing purposes.
Results:
[0106] It was found that with 20 minutes in a vegetable oil heated
to about 260.degree. C. to about 270.degree. C., torrefied pellets
had a net loss of weight of about 2.20%. With 30 minutes in heated
vegetable oil, it was found that torrefied pellets had a net weight
loss of about 6.16%. In addition, the torrefied wood pellets were
hydrophobic and had increased grindability (i.e., high Hardgrove
scale score) as compared to untorrefied wood pellets.
[0107] Without wishing to be bound by theory, it is thought that
some oil absorption occurs during the first few minutes of
torrefaction, which may result in a net increase in weight of the
biomass. Following the first few minutes, the biomass is
increasingly torrefied, thereby expelling VOCs and losing weight,
resulting in a torrefied densified biomass that has a net weight
loss as compared to the initial starting material.
Example 4
Materials and Methods
[0108] In this example, 4 different samples of densified softwood
pellets made from a blend of spruce, pine and fir, each weighing
about 0.5 kg, were tested using the small test unit described in
Example 1. Vegetable oil was heated to 220.degree. C. to about
240.degree. C. in the small container. The weight of the small
container was measured before it was filled with oil and after it
was filled with oil to determine the weight of the oil prior to the
torrefaction process. One of the 4 different samples was submerged
in the oil for a pre-determined amount of time, and then allowed to
drip dry over the small container for about 5 minutes. The small
container containing the oil was measured again following the
torrefaction process to determine the amount of oil absorbed by the
sample. This procedure was repeated for the three other
samples.
Results
[0109] The results indicated that there was less absorption with
more time in the heated oil, as described above in Example 3. As
shown in Table 3 below, sample 1, which was torrefied for about 10
minutes in the hot vegetable oil, showed about 9.6% oil absorption,
and sample 2, which was torrefied for about 15 minutes in the hot
vegetable oil, showed about 6.7% oil absorption.
TABLE-US-00004 TABLE 3 Oil Absorption During Torrefaction Sample 1
Sample 2 Sample Weight - at start 0.5 0.5 Moisture Content* 4% 4%
Sample Weight - at start; bone dry basis 0.4808 0.4808 Sample
Weight - at end 0.45 0.474 Process Time 15 10 Change in Weight of
Sample -6% -1% Oil Weight - at start 2.968 2.926 Oil Weight - at
end 2.936 2.88 % Absorption of Oil by Sample 6.6556% 9.5674% (bone
dry basis starting weight) *"Moisture Content" refers to the amount
of water (in %) in the torrefied wood pellets immediately after the
torrefaction process (i.e., after drip drying for 5 minutes).
Example 5
Materials and Methods
[0110] In this example, 4 different samples of densified softwood
pellets made from a blend of spruce, pine and fir were tested, with
each sample having a starting weight of 250 grams (0.250 kg). Each
sample was tested using the method as described above in Example 1
and the temperature, time and weight parameters as specified below
in Table 4.
Results
[0111] The results indicated that the rate of absorption of the oil
by the pellets varied over time. As shown in Table 4 below, sample
1, which was torrefied for about 15 minutes in the hot vegetable
oil, showed about 14.31% oil absorption per mass input of bone dry
pellets; sample 2, which was torrefied for about 30 minutes in the
hot vegetable oil, showed about 14.00% oil absorption per mass
input of bone dry pellets; sample 3, which was torrefied for about
45 minutes in the hot vegetable oil, showed about 13.88% oil
absorption per mass input of bone dry pellets; and sample 4, which
was torrefied for about 60 minutes in the hot vegetable oil, showed
about 11.87% oil absorption per mass input of bone dry pellets.
[0112] As shown in FIG. 7, the oil absorption initially occurred at
a higher rate during the first few minutes of torrefaction, after
which the rate of absorption decreased and then remained at a
constant rate for a period of time. As the torrefaction period
progressed further, the rate of absorption stopped and then showed
negative values indicating that oil was expelled from the torrefied
biomass during the extended periods of torrefaction. In this
example, the highest rate of absorption occurred during the first
15 minutes of torrefaction after which, the rate of absorption of
oil slowed and then remained at a constant rate through 45 minutes
of torrefaction, after which time, it appears that the densified
biomass began expelling oil previously absorbed by the densified
biomass.
[0113] FIG. 7 also shows that the heat value of the torrefied
pellets following the torrefaction process increased substantially
between 0 and 15 minutes of the torrefaction process, then to
increased slowly and fairly consistently between 15 minutes and 45
minutes of torrefaction, and eventually began to decrease after 45
minutes of torrefaction. The "heat value of samples--at end" in
Table 4 and "heat value of finished product" in FIG. 7 is the total
of the torrefied biomass plus the absorbed oil. Accordingly, the
results of this example suggest that as pelleted biomass torrefies,
the biomass expels oil (less oil in the finished product means less
heat value in the finished product derived from oil). Since there
is a net gain in heat value of the torrefied pellets over the long
term, even with the expulsion of oil, the biomass itself is gaining
heat value during the process and it is not simply due to oil
absorption.
TABLE-US-00005 TABLE 4 Oil Absorption and Heat Value for Different
Submersion Times in Canola Oil Heated to 270.degree. C. Sample 1
Sample 2 Sample 3 Sample 4 Submersion time 15 30 45 60 (minutes)
Sample Weight - at start 250.00 250.20 250.80 250.45 (g) Moisture
content (%) 1.82 1.82 1.82 1.82 Sample Weight - at start; 245.45
245.65 246.24 245.89 bone dry basis (g) Sample Weight - at 247.5
242.2 236.15 233.5 end (g) Oil Weight - at start (g) 650 612.4
572.4 651.7 Oil Weight - at end (g) 612.4 573.35 531.7 612.6 Gross
Oil Used (g) 37.6 39.05 40.7 39.1 Oil Evaporation (g) 2.47 4.65
6.52 9.90 Net Oil Absorbed (g) 35.13 34.40 34.18 29.20 % Absorption
of Oil 14.31 14.00 13.88 11.87 by Sample (bone dry basis starting
weight) Heat Value of Samples - 18.00 18.00 18.00 18.00 at start
(GJ/T @ 5% MC) Heat Value of Samples - 24.10 24.56 24.85 24.75 at
end (GJ/T) *"Moisture Content" refers to the amount of water (in %)
in the torrefied wood pellets immediately after the torrefaction
process (i.e., after drip drying for 5 minutes).
Example 6
Materials and Methods
[0114] In this example, 20 kilograms of densified softwood pellets
made from a blend of spruce, pine and fir (SPF wood pellets) were
tested. The 20 kilograms were divided into 1 kilogram samples, and
all 20 of the 1 kilogram samples were tested using the method as to
described above in Example 1 for a specific temperature (i.e.,
either 240, 245, 250, 255, 250, 265 or 270.degree. C.) and for a
specific submersion time (i.e., either 10, 15, 20, 25 or 30
minutes) at each temperature, with the exception that a PITCO.RTM.
commercial deep fryer was used for the process (rather than a small
container with a gas burner). In addition, each sample was cooled
in a water bath following the torrefaction process for 5 minutes,
then removed from the cold water bath and allowed to drain for 5
minutes before collecting the sample in a large tub. The method was
repeated for the 20 1-kg samples for each different temperature and
submersion time condition. Accordingly, for each temperature and
submersion time combination, the method was repeated 20 times with
a 1-kg sample each time. In addition, 10 1-kg samples were tested
using the method as described above in Example 1 at 280.degree. C.
for 30 minutes and 6 1-kg samples were tested using the method as
described above in Example 1 at 290.degree. C. for 30 minutes; that
is, the method was repeated 10 times for the temperature-time
combination of 280.degree. C. for 30 minutes, and the method was
repeated 6 times for the temperature-time combination of
290.degree. C. for 30 minutes, and the results for each
temperature-time combination were averaged.
[0115] The resulting torrefied densified biomass from the different
test experiments for each temperature-time condition were collected
and mixed together to form a sample batch. One kilogram of the
sample batch was collected for testing. The resulting 1-kg sample
batch was to analyzed to determine the heat values of the torrefied
pellets after each temperature-time condition.
Results
[0116] The data for this Example 6 are shown in Tables 5-13 and
reflected in FIGS. 8 and 9. This Example 6 substantiates the
findings in Example 5 (Table 4 and FIG. 7). The results indicated
that the submersion/retention time in the heated canola oil and the
temperature of the heated oil substantially correlated with the
heat value of the torrefied wood pellet at the end of the process.
As shown in Tables 5-13 below, generally, the higher the
temperature of the canola oil and the longer the time retained in
the heated canola oil, the greater the heat value of the torrefied
pellets following the torrefaction process.
[0117] The highest heat energy value was obtained when densified
pellets were submersed in 290.degree. C. canola oil for 30 minutes
(26.04 GJ/t on a bone dry basis) and the lowest heat energy value
was obtained when densified pellets were submersed in 240.degree.
C. canola oil for 10 minutes (22.78 GJ/t on a bone dry basis). All
heat energy values for the torrefied pellets were greater than the
heat energy value calculated for densified biomass that was not
torrefied (i.e., 20.49 GJ/t on a bone dry basis). Torrefying
pellets at 250.degree. C. produced a slightly higher heat energy
value than when torrefying pellets at 255.degree. C. at every time
point measured. Moreover, a submersion time of 20 minutes produced
the highest heat energy value when using canola oil at a
temperature of 265.degree. C. This data, therefore, indicated that
the torrefaction process may be tailored as desired by varying the
temperature of the canola oil and the time submersed in the heated
oil.
TABLE-US-00006 TABLE 5 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 240.degree. C. Before Torrefusion
Torrefusion Torrefusion for 10 mins. for 15 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.66 0 6.05 0 4.92 0 % Ash 0.42 0.44 0.38
0.41 0.37 0.39 % Volatile 79.99 84.79 79.81 84.95 81.19 85.39
Matter % Fixed 13.93 14.77 13.76 14.64 13.52 14.22 Carbon % Sulphur
0.03 0.04 0.02 0.02 0.02 0.02 Calorific Value (Gross) Btu/lb 8309
8807 9202 9794 9437 9925 Kcal/kg 4616 4893 5112 5441 5243 5514 GJ/T
19.33 20.49 21.4 22.78 21.95 23.09 % Carbon 47.76 50.62 51.48 54.8
52.32 55.03 % Nitrogen 0.068 0.073 0.032 0.034 0.019 0.020 % Oxygen
40.36 42.78 35.75 38.05 35.97 37.83 Torrefusion Torrefusion
Torrefusion for 20 mins. for 25 mins. for 30 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.2 0 4.12 0 3.31 0 % Ash 0.34 0.36 0.37
0.38 0.35 0.36 % Volatile 80.26 84.66 81.28 84.77 81.4 84.19 Matter
% Fixed 14.2 14.98 14.23 14.85 14.94 15.45 Carbon % Sulphur 0.01
0.01 0.01 0.01 0.01 0.01 Calorific Value (Gross) Btu/lb 9505 10026
9646 10060 9791 10127 Kcal/kg 5281 5570 5359 55.89 5440 5626 GJ/T
22.11 23.32 22.44 23.4 22.77 23.55 % Carbon 52.65 55.53 53.19 55.47
53.85 55.69 % Nitrogen 0.035 0.037 0.036 0.038 0.044 0.045 % Oxygen
35.36 37.31 35.80 37.35 35.91 37.13 *"% Moisture" with respect to
the "Torrefied Wood Pellets" on a "Wet Basis" refers to the amount
of water (in %) in the sample following cooling in the water bath
for 5 minutes and then draining for 5 minutes, as described in the
Methods.
TABLE-US-00007 TABLE 6 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 245.degree. C. Before Torrefusion
Torrefusion Torrefusion for 10 mins. for 15 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.66 0 7.28 0 6.76 0 % Ash 0.42 0.44 0.32
0.34 0.35 0.37 % Volatile 79.99 84.79 79.1 85.31 78.77 84.48 Matter
% Fixed 13.93 14.77 13.3 14.35 14.12 15.15 Carbon % Sulphur 0.03
0.04 0.01 0.01 0.01 0.01 Calorific Value (Gross) Btu/lb 8309 8807
9260 9987 9360 10039 Kcal/kg 4616 4893 5145 5548 5200 5577 GJ/T
19.33 20.49 21.54 23.23 21.77 23.35 % Carbon 47.76 50.62 51.01
55.01 51.69 55.44 % Nitrogen 0.068 0.073 0.040 0.043 0.040 0.043 %
Oxygen 40.36 42.78 35.10 37.87 34.84 37.37 Torrefusion Torrefusion
Torrefusion for 20 mins. for 25 mins. for 30 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 4.9 0 5.17 0 4.87 0 % Ash 0.41 0.43 0.41
0.43 0.39 0.41 % Volatile 80.82 84.98 79.91 84.27 80.1 84.2 Matter
% Fixed 13.87 14.59 14.51 15.3 14.64 15.39 Carbon % Sulphur 0.01
0.01 0.02 0.02 0.02 0.02 Calorific Value (Gross) Btu/lb 9583 10076
9619 10144 9702 10198 Kcal/kg 5324 5598 5344 5635 5390 5666 GJ/T
22.29 23.44 22.37 23.59 22.57 23.72 % Carbon 52.99 55.72 52.99
55.88 53.04 55.75 % Nitrogen 0.037 0.039 0.036 0.038 0.032 0.033 %
Oxygen 35.32 37.14 34.99 36.90 35.28 37.09 *"% Moisture" with
respect to the "Torrefied Wood Pellets" on a "Wet Basis" refers to
the amount of water (in %) in the sample following cooling in the
water bath for 5 minutes and then draining for 5 minutes, as
described in the Methods.
TABLE-US-00008 TABLE 7 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 250.degree. C. Before Torrefusion
Torrefusion Torrefusion for 10 mins. for 15 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.66 0 5.83 0 6.42 0 % Ash 0.42 0.44 0.36
0.38 0.38 0.41 % Volatile 79.99 84.79 79.43 84.35 79.35 84.8 Matter
% Fixed 13.93 14.77 14.38 15.27 13.85 14.79 Carbon % Sulphur 0.03
0.04 0.02 0.02 0.02 0.02 Calorific Value (Gross) Btu/lb 8309 8807
9411 9994 9459 10107 Kcal/kg 4616 4893 5228 5552 5255 5615 GJ/T
19.33 20.49 21.89 23.25 22 23.51 % Carbon 47.76 50.62 51.67 54.87
51.96 55.52 % Nitrogen 0.068 0.073 0.040 0.042 0.038 0.041 % Oxygen
40.36 42.78 35.79 38.01 34.89 37.29 Torrefusion Torrefusion
Torrefusion for 20 mins. for 25 mins. for 30 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 7.93 0 5.32 0 4.91 0 % Ash 0.4 0.43 0.4
0.42 0.41 0.43 % Volatile 78.03 84.75 79.89 84.39 79.71 83.83
Matter % Fixed 13.64 14.82 14.39 15.19 14.97 15.74 Carbon % Sulphur
0.02 0.02 0.02 0.02 0.01 0.01 Calorific Value (Gross) Btu/lb 9447
10261 9735 10283 9849 10358 Kcal/kg 5248 5701 5408 5713 5472 5754
GJ/T 21.97 23.87 22.64 23.92 22.91 24.09 % Carbon 51.48 55.91 52.93
55.91 53.61 56.38 % Nitrogen 0.034 0.037 0.034 0.036 0.036 0.038 %
Oxygen 33.93 36.85 34.90 36.85 34.59 36.38 *"% Moisture" with
respect to the "Torrefied Wood Pellets" on a "Wet Basis" refers to
the amount of water (in %) in the sample following cooling in the
water bath for 5 minutes and then draining for 5 minutes, as
described in the Methods.
TABLE-US-00009 TABLE 8 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 255.degree. C. Before Torrefusion
Torrefusion Torrefusion for 10 mins. for 15 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.66 0 8.63 0 9.5 0 % Ash 0.42 0.44 0.39
0.42 0.37 0.41 % Volatile 79.99 84.79 77.87 85.23 76.01 83.99
Matter % Sulphur 0.03 0.04 0.01 0.01 0.01 0.02 Calorific Value
(Gross) Btu/lb 8309 8807 9130 9992 9059 10011 Kcal/kg 4616 4893
5072 5551 5033 5561 GJ/T 19.33 20.49 2124 23.24 21.07 23.28 %
Carbon 47.76 50.62 51.14 55.97 51.07 56.43 % Nitrogen 0.068 0.073
0.066 0.073 0.067 0.074 % Oxygen 40.36 42.78 33.58 36.77 32.83
36.28 Torrefusion Torrefusion Torrefusion for 20 mins. for 25 mins.
for 30 mins. Wet Dry Wet Dry Wet Dry Measurements Basis Basis Basis
Basis Basis Basis Weight 1 kg 1 kg 1 kg % Moisture* 7.17 0 6.86 0
6.77 0 % Ash 0.44 0.48 0.51 0.55 0.41 0.44 % Volatile 78.75 84.84
78.09 83.84 78.49 84.2 Matter % Sulphur 0.02 0.02 0.01 0.01 0.02
0.03 Calorific Value (Gross) Btu/lb 9437 10166 9447 10143 9564
10259 Kcal/kg 5243 5648 5248 5635 5313 5700 GJ/T 21.95 23.65 21.97
23.59 22.25 23.86 % Carbon 52.63 56.69 52.96 56.87 53.5 57.38 %
Nitrogen 0.063 0.067 0.061 0.065 0.062 0.067 % Oxygen 33.37 35.94
33.30 35.73 32.86 35.23 *"% Moisture" with respect to the
"Torrefied Wood Pellets" on a "Wet Basis" refers to the amount of
water (in %) in the sample following cooling in the water bath for
5 minutes and then draining for 5 minutes, as described in the
Methods.
TABLE-US-00010 TABLE 9 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 260.degree. C. Before Torrefusion
Torrefusion Torrefusion for 10 mins. for 15 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.66 0 10.01 0 7.62 0 % Ash 0.42 0.44 0.39
0.44 0.39 0.42 % Volatile 79.99 84.79 76.06 84.52 78.25 84.7 Matter
% Sulphur 0.03 0.04 0.01 0.01 0.01 0.01 Calorific Value (Gross)
Btu/lb 8309 8807 8989 9989 9475 10256 Kcal/kg 4616 4893 4994 5550
5264 5698 GJ/T 19.33 20.49 20.91 23.24 22.04 23.86 % Carbon 47.76
50.62 50.81 56.47 52.5 56.83 % Nitrogen 0.068 0.073 0.068 0.075
0.064 0.069 % Oxygen 40.36 42.78 32.59 36.19 33.13 35.87
Torrefusion Torrefusion Torrefusion for 20 mins. for 25 mins. for
30 mins. Wet Dry Wet Dry Wet Dry Measurements Basis Basis Basis
Basis Basis Basis Weight 1 kg 1 kg 1 kg % Moisture* 9.13 0 6.92 0
6.59 0 % Ash 0.37 0.41 0.39 0.42 0.4 0.43 % Volatile 75.83 83.44
77.91 83.7 77.42 82.89 Matter % Sulphur 0.01 0.01 0.02 0.02 0.02
0.03 Calorific Value (Gross) Btu/lb 9376 10318 9677 10397 9771
10461 Kcal/kg 5209 5732 5376 5776 5428 5812 GJ/T 21.81 24 22.51
24.18 22.73 24.33 % Carbon 51.92 57.14 53.42 57.39 53.87 57.68 %
Nitrogen 0.063 0.070 0.069 0.074 0.058 0.062 % Oxygen 32.34 35.58
32.86 35.31 32.71 35.00 *"% Moisture" with respect to the
"Torrefied Wood Pellets" on a "Wet Basis" refers to the amount of
water (in %) in the sample following cooling in the water bath for
5 minutes and then draining for 5 minutes, as described in the
Methods.
TABLE-US-00011 TABLE 10 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 265.degree. C. Before Torrefusion
Torrefusion Torrefusion for 10 mins. for 15 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.66 0 8.35 0 9.44 0 % Ash 0.42 0.44 0.38
0.41 0.39 0.43 % Volatile 79.99 84.79 77.45 84.51 75.58 83.46
Matter % Sulphur 0.03 0.04 0.02 0.02 0.01 0.01 Calorific Value
(Gross) Btu/lb 8309 8807 9341 10193 9326 10298 Kcal/kg 4616 4893
5190 5663 5181 5721 GJ/T 19.33 20.49 21.73 23.71 21.69 23.95 %
Carbon 47.76 50.62 51.67 56.38 51.66 57.05 % Nitrogen 0.068 0.073
0.068 0.074 0.064 0.071 % Oxygen 40.36 42.78 33.35 36.39 32.34
35.71 Torrefusion Torrefusion Torrefusion for 20 mins. for 25 mins.
for 30 mins. Wet Dry Wet Dry Wet Dry Measurements Basis Basis Basis
Basis Basis Basis Weight 1 kg 1 kg 1 kg % Moisture* 7.53 0 7.06 0
6.76 0 % Ash 0.37 0.4 0.38 0.41 0.4 0.43 % Volatile 77.2 83.49
76.74 82.57 77.25 82.86 Matter % Sulphur 0.01 0.01 0.01 0.01 0.01
0.01 Calorific Value (Gross) Btu/lb 9759 10554 9763 10504 9823
10535 Kcal/kg 5422 5863 5424 5836 5457 5853 GJ/T 22.7 24.55 22.71
24.43 22.85 24.51 % Carbon 53.85 5824 53.87 57.96 54.33 58.27 %
Nitrogen 0.063 0.068 0.062 0.067 0.053 0.057 % Oxygen 31.88 34.46
32.31 34.76 32.10 34.42 *"% Moisture" with respect to the
"Torrefied Wood Pellets" on a "Wet Basis" refers to the amount of
water (in %) in the sample following cooling in the water bath for
5 minutes and then draining for 5 minutes, as described in the
Methods.
TABLE-US-00012 TABLE 11 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 270.degree. C. Before Torrefusion
Torrefusion Torrefusion for 10 mins. for 15 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 5.66 0 9.36 0 10.12 0 % Ash 0.42 0.44 0.34
0.38 0.36 0.4 % Volatile 79.99 84.79 76.4 84.3 75.3 83.77 Matter %
Fixed 13.93 14.77 13.90 15.32 14.22 15.83 Carbon % Sulphur 0.03
0.04 0.03 0.03 0.03 0.03 Calorific Value (Gross) Btu/lb 8309 8807
9347 10313 9347 10399 Kcal/kg 4616 4893 5193 5729 5193 5777 GJ/T
19.33 20.49 21.74 23.99 21.74 24.19 % Carbon 47.76 50.62 51.74
57.08 51.82 57.65 % Nitrogen 0.068 0.073 0.149 0.164 0.139 0.155 %
Oxygen 40.36 42.78 32.31 35.66 31.47 35.03 Torrefusion Torrefusion
Torrefusion for 20 mins. for 25 mins. for 30 mins. Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Weight 1
kg 1 kg 1 kg % Moisture* 8.26 0 7.28 0 7.2 0 % Ash 0.41 0.44 0.38
0.41 0.38 0.41 % Volatile 75.32 82.11 77.14 83.2 76.3 82.23 Matter
% Fixed -- -- 15.20 16.39 16.12 17.36 Carbon % Sulphur 0.01 0.01
0.03 0.03 0.03 0.03 Calorific Value (Gross) Btu/lb 9623 10490 9858
10631 9918 10688 Kcal/kg 5346 5828 5477 5906 5510 5938 GJ/T 22.38
24.4 22.93 24.73 23.07 24.86 % Carbon 53.39 58.19 54.39 58.66 54.85
59.11 % Nitrogen 0.068 0.074 0.134 0.145 0.134 0.144 % Oxygen 31.64
34.51 31.50 33.98 31.09 33.50 *"% Moisture" with respect to the
"Torrefied Wood Pellets" on a "Wet Basis" refers to the amount of
water (in %) in the sample following cooling in the water bath for
5 minutes and then draining for 5 minutes, as described in the
Methods.
TABLE-US-00013 TABLE 12 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 280.degree. C. Before Torrefusion
Torrefusion for 30 mins. Measurements Wet Basis Dry Basis Wet Basis
Dry Basis Weight 1 kg 1 kg % Moisture* 5.66 0 9.05 0 % Ash 0.42
0.44 0.41 0.45 % Volatile Matter 79.99 84.79 73.75 81.09 % Fixed
Carbon 13.93 14.77 16.79 18.46 % Sulphur 0.03 0.04 0.03 0.03
Calorific Value (Gross) Btu/lb 8309 8807 9913 10900 Kcal/kg 4616
4893 5507 6056 GJ/T 19.33 20.49 23.06 25.35 % Carbon 47.76 50.62
54.62 60.06 % Nitrogen 0.068 0.073 0.138 0.152 % Oxygen 40.36 42.78
29.60 32.54 *"% Moisture" with respect to the "Torrefied Wood
Pellets" on a "Wet Basis" refers to the amount of water (in %) in
the sample following cooling in the water bath for 5 minutes and
then draining for 5 minutes, as described in the Methods.
TABLE-US-00014 TABLE 13 Heat Value of Torrefied Wood Pellets Before
and After Torrefusion at 290.degree. C. Before Torrefusion
Torrefusion for 30 mins. Measurements Wet Basis Dry Basis Wet Basis
Dry Basis Weight 1 kg 1 kg % Moisture* 5.66 0 10.03 0 % Ash 0.42
0.44 0.43 0.47 % Volatile Matter 79.99 84.79 71.15 79.08 % Fixed
Carbon 13.93 14.77 18.39 20.45 % Sulphur 0.03 0.04 0.03 0.03
Calorific Value (Gross) Btu/lb 8309 8807 10071 11194 Kcal/kg 4616
4893 5595 6219 GJ/T 19.33 20.49 23.42 26.04 % Carbon 47.76 50.62
55.91 62.15 % Nitrogen 0.068 0.073 0.143 0.159 % Oxygen 40.36 42.78
27.31 30.35 *"% Moisture" with respect to the "Torrefied Wood
Pellets" on a "Wet Basis" refers to the amount of water (in %) in
the sample following cooling in the water bath for 5 minutes and
then draining for 5 minutes, as described in the Methods.
Example 7
Materials and Methods
[0118] The same method as described in Example 6 was used in this
example, including the different submersion times in the heated
canola oil (i.e., either 10, 15, 20, 25 or 30 minutes) and the
different temperatures of the canola oil used in the process (i.e.,
either 240, 245, 250, 255, 250, 265 or 270.degree. C.; and
submersing for 30 minutes at 280.degree. C. or 290.degree. C.).
[0119] In this example, the resulting data was analyzed to
determine the carbon content of the torrefied pellets after each
temperature-time combination.
Results
[0120] The data for this Example 7 are shown in Tables 5-13 above
and in FIG. 10. The results indicated that the carbon percentage of
the torrefied wood pellets at the end of the torrefaction process
generally increased with an increase in submersion/retention time
in heated canola oil and with an increase in the temperature of the
heated oil. As shown in FIG. 10, there was a general upward trend
in the carbon content of the torrefied wood pellets with an
increase in temperature of the canola oil. There was also
substantial correlation between carbon content and submersion time
in heated oil.
[0121] The highest carbon content was obtained when the densified
wood pellets were submersed in 290.degree. C. canola oil for 30
minutes (62.15 carbon % on a bone dry basis) and the lowest carbon
content was obtained when the densified wood pellets were submersed
in 240.degree. C. canola oil for 10 minutes (54.80 carbon % on a
bone dry basis). The carbon content for all torrefied pellets was
greater than the carbon percentage calculated for densified biomass
that was not torrefied (i.e., 50.62 carbon % on a bone dry
basis).
Example 8
Materials and Methods
[0122] The amount of evaporation of the different types of
combustible liquids were tested. Each combustible liquid was tested
once using the following evaporation test. The small test unit as
described above for Example 1 was used for this test. The small
container was placed on the scale and the net weight of the empty
small container was measured. A volume of oil was measured out and
poured into the small container and a lid placed on top of the
small container. The gas burner was then turned on to 270.degree.
C., and the temperature of the oil was monitored. Once the desired
temperature of 270.degree. C. was reached, the small container with
the vegetable oil was removed from the gas burner and the small
container with the vegetable oil was calculated. The small
container with the vegetable oil was then put back on the gas
burner and allowed to heat for 30 minutes at 270.degree. C. The
weight of the small container with the vegetable oil was measured
after 30 minutes of heating and the reduction in weight caused by
evaporation recorded.
[0123] The different combustible liquids tested were: canola oil,
sunflower oil, corn oil, peanut oil, bar and chain oil, 5W30 oil,
automatic transmission fluid, hydraulic fluid AW32, gear oil 80W90,
and paraffin wax.
Results
[0124] The results indicated that evaporation of each of the
different combustible liquids after heating at 270.degree. C. for
30 minutes was negligible. Accordingly, evaporation of the
combustible liquids was not taken into account when calculating oil
absorption by torrefied densified biomass following a torrefaction
process.
Example 9
Materials and Methods
[0125] This Example 9 was performed in order to compare the oil
absorption by densified pellets when using canola oil as the
combustible liquid versus paraffin wax as the combustible
liquid.
[0126] In this example, densified softwood pellets made from a
blend of spruce, pine and fir (SPF wood pellets) were tested. A 250
gram sample of SPF wood pellets was weighed out and a wire sieve
for holding the densified material was separately weighed. The
sample of densified material was then loaded into the wire sieve
and the total weight of the sieve plus densified material was
measured and then set aside for testing purposes. The small test
unit described in Example 1 was used for this example. As an
initial step, the small container was placed on a scale and the net
weight of the small container was measured. A volume of oil (either
canola oil or paraffin wax) was measured out and poured into the
small container and the total weight of the small container plus
oil was measured, thereby providing a net weight for the oil.
[0127] Once the measurements of the oil were complete, the gas
burner was turned on to a specific temperature (either 250.degree.
C., 260.degree. C. or 270.degree. C.), and the temperature of the
oil was monitored.
[0128] After the temperature of the oil was stabilized at the
desired temperature, the following weights were measured: (a) the
weight of the small container plus the heated oil; (b) the weight
of the small container plus the heated oil plus the lid for the
small container plus a temperature probe inserted into the small
container; and (c) the weight of the small container plus the
heated oil plus the lid for the small container plus a temperature
probe inserted into the small container plus the 250 gram sample of
densified material loaded in the wire sieve and placed on top of
the small container (i.e., not yet submerged in the small
container).
[0129] Upon completion of the above measurements, the wire sieve
containing the densified material was submerged in the heated oil
and the small container covered with a lid. The densified material
was submerged in the heated oil for a specific amount of time
(either 15 or 30 minutes). After submersion for the desired time,
the gas burner was turned off and the total weight of the small
container, oil, lid, temperature probe, sieve and densified
material was measured (with the sieve and densified material still
submerged in the oil). The wire sieve with the densified material
contained therein was then removed from the small container and
oil, and allowed to drain over the small container for about five
minutes. The drained wire sieve with the densified material
contained therein was weighed, and the densified material was
subsequently weighed separately. With the sieve and densified
material removed, the total weight of the small container, oil, lid
and temperature probe was weighed and then the total weight of the
small container plus oil was subsequently weighed separately.
[0130] The bone dry weight of the torrefied pellets was then
calculated (i.e., to provide a bone dry basis for the torrefied
pellets), and then the bone dry weight of the pellets was compared
to the loss of oil and a % oil absorption calculated.
[0131] The above process was completed twice for each temperature,
time and oil combination (i.e., two test runs done for each
different type of oil being tested at each different temperature
and submersion time), with each process starting with a 250 gram
sample of densified pellets.
Results
[0132] As shown in FIG. 11, when canola oil was used as the
combustible liquid for the torrefaction process, oil absorption by
the densified biomass tended to generally increase when the
temperature of the canola oil was increased from 250.degree. C. to
260.degree. C., but then declined slightly when torrefied at a
temperature of 270.degree. C. There also appeared to be a general
decrease in weight of the torrefied densified biomass with
increased temperature; however, carrying out the torrefaction
process at 260.degree. C. for 30 minutes caused an increase in
weight (i.e., +11.48 g compared to starting weight, which amounted
to a weight of 249.35 g) as compared to carrying out the process at
250.degree. C. for 30 minutes (+8.53 g compared to starting weight,
which amounted to an end weight of 246.4 g). This increase in
weight corresponded with an increase in oil absorption for this
temperature-time condition (i.e., an oil absorption of 21.02% per
mass input of bone dry pellets at 260.degree. C. for 30 minutes, as
compared to an oil absorption of 16.65% at 250.degree. C. for 30
minutes), which suggested that the weight increase is due to the
increased oil absorption when torrefying at 260.degree. C. for 30
minutes. The slight decline in oil absorption when a temperature of
270.degree. C. was used (i.e., 16.86% oil absorption at 15 minutes
and 17.11% at 30 minutes) also corresponded to a decrease in the
weight of the torrefied densified biomass at this temperature
(i.e., -1.28 g at 15 minutes and -5.47 g at 30 minutes), further
suggesting that oil absorption is correlated with the weight of the
resulting torrefied densified biomass. This data also correlated
with the data obtained from Examples 3 and 5.
[0133] FIG. 12 shows that similar results were obtained when
paraffin wax was used as the combustible liquid. Oil absorption by
the densified biomass tended to generally increase when the
temperature of the paraffin wax was increased from 250.degree. C.
to 260.degree. C., but then declined when torrefied at a
temperature of 270.degree. C. The rate of increase in the oil
absorption was greater for paraffin wax than for canola oil when
increasing the temperature from 250.degree. C. to 260.degree. C.
and when increasing the submersion time at each temperature point.
As with canola oil, there also appeared to be a general decrease in
weight of the torrefied densified biomass with increased
temperature. However, there did not seem to be a correlation
between the weight of the torrefied densified biomass at the end of
the process and the oil absorbed by the torrefied densified biomass
as seen with canola oil.
[0134] FIG. 13 and Tables 14 and 15 below illustrate that generally
more canola oil was lost during the torrefaction process when
canola oil was used as the combustible liquid. The amount of oil
loss was generally similar when using either canola oil or paraffin
wax, except when torrefying at 250.degree. C. The amount of
paraffin wax lost when torrefying at 250.degree. C. for 15 minutes
was significantly less with paraffin wax. Furthermore, the rate of
loss of oil between 15 minutes of torrefaction and 30 minutes of
torrefaction at 250.degree. C. when paraffin wax was used as the
combustible liquid seemed to be significantly greater than when
canola oil was used.
[0135] As shown in FIG. 14, when using canola oil as the
combustible liquid rather than paraffin wax, the reduction in
weight of the torrefied pellet as compared to the starting biomass
differed. For both, as shown in Tables 14 and 15 and described
above, the weight of the torrefied pellets generally tended to
decrease with increased temperature. However, with canola oil, the
weight of the torrefied pellets was greater than the starting
densified pellets when the torrefaction process was carried out at
250.degree. C. and 260.degree. C. There was only a reduction in
weight as compared to the starting densified pellets when
torrefying at 270.degree. C. With paraffin wax, the end weight of
the torrefied pellet was generally less than the starting weight of
the densified pellet, except when torrefying at 250.degree. C. for
15 minutes. Paraffin wax generally led to a greater reduction in
weight at all time points and temperatures. Without wishing to be
bound by theory, these results may be due to the biomass absorbing
less paraffin wax during the torrefaction process than when canola
oil is used. Less absorption of the paraffin wax may be as a result
of the longer molecular chain of paraffin wax and perhaps a greater
evaporation rate of paraffin wax.
TABLE-US-00015 TABLE 14 Canola Oil Absorption by Pellets and Weight
Reduction of Pellets During Torrefaction at Different Temperatures
and Submersion Times Sample 1 Sample 2 Sample 3 Sample 4 Sample 5
Sample 6 Submersion Time (mins.) 15 30 15 30 15 30 Temperature
(.degree. C.) 250 250 260 260 270 270 Sample Weight - at start;
250.00 250.00 250.00 250.00 250.00 250.00 wet basis (g) Moisture
Content (%)* 4.85 4.85 4.85 4.85 4.85 4.85 Sample Weight - at
start; 237.88 237.88 237.88 237.88 237.88 237.88 bone dry basis (g)
Sample Weight - at end; 251.30 246.40 244.48 249.35 236.60 232.40
bone dry basis (g) Change in Weight - bone dry +13.43 +8.53 +6.60
+11.48 -1.28 -5.47 basis (g) Pot + Oil Weight - at start 2,390.20
2,350.75 2,355.40 2,359.20 2,352.90 2,346.70 (g) Pot + Oil Weight -
at end (g) 2,356.20 2,311.15 2,318.10 2,309.20 2,312.80 2,306.00
Change in Pot + Oil Weight -34.00 -39.60 -37.30 -50.00 -40.10
-40.70 (g) Reduction in Pellet Weight 5.64 3.58 2.78 4.82 -0.54
-2.30 Start to Finish (%) % Oil Absorption by Sample 14.29% 16.65%
15.68% 21.02% 16.86% 17.11% Including Evaporation (bone dry basis)
*"Moisture Content" refers to the amount of water in the samples
immediately after the torrefaction process (i.e., after drip drying
for 5 minutes).
TABLE-US-00016 TABLE 15 Paraffin Wax Absorption by Pellets and
Weight Reduction of Pellets During Torrefaction at Different
Temperatures and Submersion Times Sample 1 Sample 2 Sample 3 Sample
4 Sample 5 Sample 6 Submersion Time (mins.) 15 30 15 30 15 30
Temperature (.degree. C.) 250 250 260 260 270 270 Sample Weight -
at start; 250.00 250.00 250.00 250.00 250.00 250.00 wet basis (g)
Moisture Content (%)* 4.85 4.85 4.85 4.85 4.85 4.85 Sample Weight -
at start; 237.88 237.88 237.88 237.88 237.88 237.88 bone dry basis
(g) Sample Weight - at end; 242.60 234.95 231.40 230.75 219.15
210.95 bone dry basis (g) Change in Weight - bone dry +4.72 -2.93
-6.47 -7.13 -18.73 -26.93 basis (g) Pot + Oil Weight - at start
2,185.10 2,222.35 2,183.30 2,212.05 2,252.75 2,214.60 (g) Pot + Oil
Weight - at end (g) 2,178.60 2,186.40 2,151.30 2,162.85 2,219.20
2,176.45 Change in Pot + Oil Weight 6.50 35.95 32.00 49.20 33.55
38.15 (g) Reduction in Pellet Weight 1.99 -1.23 -2.72 -3.00 -7.87
-11.32 Start to Finish (%) % Oil Absorption by Sample 3 15 13 21 14
16 Including Evaporation (bone dry basis) *"Moisture Content"
refers to the amount of water in the samples immediately after the
torrefaction process (i.e., after drip drying for 5 minutes).
Example 10
Materials and Methods
[0136] The torrefied pellets from Example 6, which proceeded
through the torrefaction process at different temperatures
(240.degree. C., 245.degree. C., 250.degree. C., 255.degree. C.,
260.degree. C., 265.degree. C., 270.degree. C., 280.degree. C. or
290.degree. C.) for different submersion times (10, 15, 20, 25 or
30 minutes), were tested to determine the hydrophobic nature of the
torrefied pellets. To do this, a 953.63 gram sample from each batch
of processed torrefied densified biomass corresponding to a
specific temperature-time condition was measured out and submersed
in water for two weeks (i.e., 14 days). Once removed from the
water, the samples were allowed to drain in a sieve for 5 minutes,
and then each sample was weighed to measure the change in weight of
the sample. This measurement was compared to the weight of the
water, and the amount of water absorbed by each sample was
calculated.
Results
[0137] The data in Table 16 indicated that as the temperature of
the torrefaction process increased (i.e., the temperature of the
heated canola oil), the hydrophobic nature of the resulting product
increased. This data is represented in FIGS. 15 and 16, which show
that the amount of water absorbed by the torrefied densified
pellets following the torrefaction process correlated with the
temperature of the torrefaction process. When torrefied at higher
temperatures (such as 270.degree. C., 280.degree. C. or 290.degree.
C.) rather than at lower temperatures (such as 240.degree. C.), the
resulting torrefied densified pellets absorbed less water into the
pellets.
[0138] The submersion time in the heated canola oil appeared to be
less material to the hydrophobic nature of the resulting product;
however, the results indicated that generally for shorter
submersion times (e.g., 10 minutes), more water was absorbed by the
resulting torrefied densified pellets compared to when longer
submersion times were used for the torrefaction process (e.g., 30
minutes).
TABLE-US-00017 TABLE 16 Water Absorption Following Torrefaction
Torrefaction Process Gross Weight of Net Torrefied Water
temperature time Weight of Container Weight of Sample Absorbed
Sample (.degree. C.) (minutes) Water (g) (g) Water (g) Weight (g)
(g) 1 240 10 1,536.50 46.37 1490.13 953.63 536.50 2 240 15 1,437.20
46.37 1390.83 953.63 437.20 3 240 20 1,397.50 46.37 1351.13 953.63
397.50 4 240 25 1,391.50 46.37 1345.13 953.63 391.50 5 240 30
1,394.00 46.37 1347.63 953.63 394.00 6 245 10 1,448.35 46.37
1401.98 953.63 448.35 7 245 15 1,377.20 46.37 1330.83 953.63 377.20
8 245 20 1,377.85 46.37 1331.48 953.63 377.85 9 245 25 1,336.45
46.37 1290.08 953.63 336.45 10 245 30 1,335.70 46.37 1289.33 953.63
335.70 11 250 10 1,421.80 46.37 1375.43 953.63 421.80 12 250 15
1,337.90 46.37 1291.53 953.63 337.90 13 250 20 1,305.20 46.37
1258.83 953.63 305.20 14 250 25 1,319.70 46.37 1273.33 953.63
319.70 15 250 30 1,285.55 46.37 1239.18 953.63 285.55 16 255 10
1358.10 46.37 1311.73 953.63 358.10 17 255 15 1286.25 46.37 1239.88
953.63 286.25 18 255 20 1291.85 46.37 1245.48 953.63 291.85 19 255
25 1260.05 46.37 1213.68 953.63 260.05 20 255 30 1243.35 46.37
1196.98 953.63 243.35 21 260 10 1294.50 46.37 1248.13 953.63 294.50
22 260 15 1290.30 46.37 1243.93 953.63 290.30 23 260 20 1232.85
46.37 1186.48 953.63 232.85 24 260 25 1227.95 46.37 1181.58 953.63
227.95 25 260 30 1223.95 46.37 1177.58 953.63 223.95 26 265 10
1281.10 46.37 1234.73 953.63 281.10 27 265 15 1224.85 46.37 1178.48
953.63 224.85 28 265 20 1225.40 46.37 1179.03 953.63 225.40 29 265
25 1208.25 46.37 1161.88 953.63 208.25 30 265 30 1207.40 46.37
1161.03 953.63 207.40 31 270 10 1236.80 46.37 1190.43 953.63 236.80
32 270 15 1184.40 46.37 1138.03 953.63 184.40 33 270 20 1192.30
46.37 1145.93 953.63 192.30 34 270 25 1164.10 46.37 1117.73 953.63
164.10 35 270 30 1167.80 46.37 1121.43 953.63 167.80 36 280 30
1161.60 46.37 1115.23 953.63 161.60 37 290 30 1149.90 46.37 1103.53
953.63 149.90
Example 11
Materials and Methods
[0139] In this example, both densified softwood pellets made from a
blend of spruce, pine and fir (SPF wood pellets) and densified hog
fuel were tested. A 250 gram sample of either SPF wood pellets or
densified hog fuel was weighed out and a wire sieve for holding the
densified material was separately weighed. The sample of densified
material was then loaded into the wire sieve and the total weight
of the sieve plus densified material was measured and then set
aside for testing purposes using the small test unit described in
Example 1.
[0140] As an initial step, the small container was placed on a
scale and the net weight of the empty small container was measured.
A volume of oil (one of the following: sunflower oil, corn oil,
peanut oil, canola oil, bar and chain oil, 5W30 oil, automatic
transmission fluid, hydraulic fluid AW32, gear oil 80W90, or
paraffin wax) was measured out and poured into the small container
and the total weight of the small container plus oil was measured,
thereby providing a net weight for the oil.
[0141] Once the measurements of the oil were complete, the gas
burner was turned on to the testing temperature of 270.degree. C.,
and the temperature of the oil was monitored.
[0142] After the temperature of the oil was stabilized at
270.degree. C., the following weights were measured: (a) the weight
of the small container plus the heated oil; (b) the weight of the
small container plus the heated oil plus the lid for the small
container plus a temperature probe inserted into the small
container; and (c) the weight of the small container plus the
heated oil plus the lid for the small container plus a temperature
probe inserted into the small container plus the 250 gram sample of
densified material loaded in the wire sieve and placed on top of
the small container (i.e., not yet submerged in the small
container).
[0143] Upon completion of the above measurements, the wire sieve
containing the densified material was submerged in the heated oil
and the small container covered with a lid. The densified material
was submerged in the heated oil for 30 minutes. After the 30 minute
submersion time, the small container was turned off and the total
weight of the small container, oil, lid, temperature probe, sieve
and densified material was measured (with the sieve and densified
material still submerged in the oil). The wire sieve with the
densified material contained therein was then removed from the
small container and oil, and allowed to drain over the small
container for 5 minutes, except in the case of hog fuel, which was
allowed to drain for 10 minutes. The drained wire sieve with the
densified material contained therein was weighed, and the densified
material was subsequently weighed separately. With the sieve and
densified material removed, the total weight of the small
container, oil, lid and temperature probe was weighed and then the
total weight of the small container plus oil was subsequently
weighed separately.
[0144] The bone dry weight of the torrefied pellets was then
calculated, and then the bone dry weight of the pellets was
compared to the loss of oil (net of evaporation of the oil) and
calculated as a percentage loss of canola oil.
[0145] The above process was done twice for each different type of
oil used (i.e., two test runs done for each different type of oil
being tested), with each process starting with a 250 gram sample of
densified pellets.
Results
[0146] The data from this example are shown in Table 17 and FIG. 17
for the plant-derived oils, and in Table 18 and FIG. 18 for the
petroleum-based oils. These results indicated that torrefaction of
the densified biomass in the plant-derived oils generally tended to
result in less oil absorption by the resulting torrefied densified
biomass, when compared to torrefaction of the densified biomass in
the petroleum-based oils.
[0147] Amongst the plant-derived oils, torrefaction of SPF pellets
in sunflower oil at 270.degree. C. for 30 minutes resulted in the
least amount of oil being absorbed by the densified biomass (on
average about 11.38% oil absorption). Canola oil resulted in the
most oil absorption by the torrefied densified biomass after
torrefaction in canola oil at 270.degree. C. for 30 minutes (on
average about 12.12% oil absorption).
[0148] Amongst the petroleum-based oils, paraffin wax followed by
5W30 motor oil resulted in the least amount of oil absorption by
the torrefied densified biomass (on average about 16.48% and 17.10%
oil absorption, respectively). Gear oil (80W90) resulted in the
most oil absorption by the torrefied densified biomass after
torrefaction in the gear oil at 270.degree. C. for 30 minutes (on
average about 24.32% oil absorption).
[0149] The data in Tables 17 and 18 also indicated that
torrefaction in plant-derived oils resulted in a generally lower
average net loss in weight of the biomass as compared to
torrefaction in petroleum-based oils. Amongst the plant-derived
oils, torrefaction in peanut oil resulted in the lowest average net
loss in weight (i.e., a net loss in weight of about 7.70 g) and
torrefaction in sunflower oil resulted in the highest average net
loss in weight (i.e., a net loss in weight of about 10.85 g).
Amongst the petroleum-based oils, torrefaction in bar and chain oil
and hydraulic fluid (AW32) resulted in the lowest average net
losses in weight (i.e., net losses in weight of about 10.70 g and
10.60 g, respectively) and torrefaction in automatic transmission
fluid (ATF) resulted in the highest average net loss in weight
(i.e., a net loss in weight of about 17.23 g).
[0150] As shown in Tables 17 and 18, when hog fuel was used as the
starting densified biomass, significantly greater oil absorption
occurred by the hog fuel biomass in plant-derived oils (canola oil)
and petroleum-based oils (paraffin wax) and a significantly greater
average net loss in weight occurred when the hog fuel biomass was
torrefied in plant-derived oils (canola oil) and petroleum-based
oils (paraffin wax).
TABLE-US-00018 TABLE 17 Oil Absorption and Net Loss of Mass for
Different Plant-derived Oils Oil Net Loss Average Oil Average Net
Combustible Densified Absorption in Weight Absorption Loss in
Sample Liquid Biomass (%) (g) (%) Weight (g) 1 Sunflower oil SPF
pellets 10.81 12.25 11.38 10.85 2 Sunflower oil SPF pellets 11.96
9.45 1 Corn oil SPF pellets 11.25 9.15 11.88 9.33 2 Corn oil SPF
pellets 12.52 9.50 1 Peanut oil SPF pellets 12.02 7.35 11.76 7.70 2
Peanut oil SPF pellets 11.50 8.05 1 Canola oil SPF pellets 10.93
12.05 12.12 10.58 2 Canola oil SPF pellets 13.30 9.10 1 Canola oil
Hog fuel 213.40 74.00 239.27 88.23 2 Canola oil Hog fuel 265.13
102.45
TABLE-US-00019 TABLE 18 Oil Absorption and Net Loss of Mass for
Different Petroleum-Based Oils Oil Net Loss in Average Oil Average
Net Combustible Densified Absorption Weight Absorption Loss in
Sample Liquid Biomass (%) (g) (%) Weight (g) 1 Bar and Chain oil
SPF pellets 19.71 11.00 20.39 10.70 2 Bar and Chain oil SPF pellets
21.07 10.40 1 5W30 motor oil SPF pellets 19.18 14.25 17.10 13.25 2
5W30 motor oil SPF pellets 15.02 12.25 1 Automatic SPF pellets
22.70 18.20 20.90 17.23 transmission fluid 2 Automatic SPF pellets
19.10 16.25 transmission fluid 1 Hydraulic fluid SPF pellets 25.72
9.05 19.99 10.60 (AW32) 2 Hydraulic fluid SPF pellets 14.26 12.15
(AW32) 1 Gear oil (80W90) SPF pellets 34.09 13.70 24.32 12.93 2
Gear oil (80W90) SPF pellets 14.55 14.75 1 Paraffin wax SPF pellets
15.35 14.50 16.48 14.48 2 Paraffin wax SPF pellets 17.61 14.45 1
Paraffin wax Hog fuel 230.89 73.15 231.00 65.80 2 Paraffin wax Hog
fuel 231.10 58.45
Example 12
Materials and Methods
[0151] In this example, 2 kilograms of densified softwood pellets
made from a blend of spruce, pine and fir (SPF wood pellets) were
tested. The 2 kilograms were divided into 1 kilogram samples, and
each 1 kilogram sample was tested using the method as described
above in Example 1 in a combustible liquid (either a plant-derived
oil or a petroleum-based oil) heated to a temperature of
270.degree. C. for 30 minutes. The method was repeated for the 2
1-kg samples for each different type of oil. Accordingly, for each
type of oil, the method was to repeated twice with a 1-kg sample
each time. The resulting torrefied densified biomass from both test
experiments for each type of oil were collected and mixed together
to form a sample batch. One kilogram of the sample batch was
collected for testing.
[0152] In this example, the resulting 1-kg sample batch was
analyzed to determine the heat energy values of the torrefied
pellets after each temperature-time condition.
[0153] The plant-derived oils used in this example included peanut
oil, sunflower oil and corn oil. The petroleum-based oils used in
this example included automatic transmission fluid, gear oil 80W90,
motor oil (5W30), bar and chain oil, and hydraulic fluid AW32.
Results
[0154] The results shown in Tables 19 and 20 below indicated that
the petroleum-based oils generally tended to result in torrefied
densified biomass having slightly higher heat energy values than
the densified biomass that was torrefied in plant-derived oils. For
example, the heat energy values for torrefied densified biomass
processed in petroleum-based oils were approximately 26 gigajoules
per metric tonne (GJ/t); whereas the heat energy values for biomass
processed in plant-derived oils were approximately about 24-25
GJ/t. This difference may be due to greater oil absorption by
petroleum-processed biomass, as shown in Example 10 above.
[0155] The results further indicated that all of the plant-derived
oils produced torrefied products with approximately similar heat
energy values, and all of the petroleum-based oils similarly
produced torrefied products with approximately similar heat energy
values.
TABLE-US-00020 TABLE 19 Heat Value of Torrefied Wood Pellets After
Torrefusion at 270.degree. C. for 30 Minutes in Plant-derived Oils
Sunflower oil Corn Oil Peanut Oil Wet Dry Wet Dry Wet Dry
Measurements Basis Basis Basis Basis Basis Basis Weight 1 kg 1 kg 1
kg % Moisture* 1.04 0 0.78 0 1.52 0 % Ash 0.47 0.48 0.44 0.44 0.43
0.44 % Volatile Matter 80.96 81.81 80.69 81.32 80.22 81.46 % Fixed
Carbon 17.53 17.71 18.09 18.24 17.83 18.10 % Sulphur 0.02 0.02 0.02
0.02 0.02 0.02 Calorific Value (Gross) Btu/lb 10615 10727 10616
10699 10426 10587 Kcal/kg 5897 5959 5898 5944 5792 5881 GJ/T 24.69
24.95 24.69 24.89 24.25 24.62 % Carbon 58.27 58.88 58.63 59.09
57.72 58.61 % Nitrogen 0.15 0.15 0.14 0.14 0.13 0.13 % Oxygen 33.34
33.69 33.29 33.56 33.53 34.04 *"% Moisture" refers to the amount of
water in the samples immediately after the torrefaction process
(i.e., after drip drying for 5 minutes).
TABLE-US-00021 TABLE 20 Heat Value of Torrefied Wood Pellets After
Torrefusion at 270.degree. C. for 30 Minutes in Petroleum-Based
Oils Automatic Bar & Chain AW32 Transmission Gear Oil Motor Oil
Oil Hydraulic Oil Fluid 80W90 5W30 Wet Dry Wet Dry Wet Dry Wet Dry
Wet Dry Measurements Basis Basis Basis Basis Basis Basis Basis
Basis Basis Basis Weight 1 kg 1 kg 1 kg 1 kg 1 kg % Moisture* 0.72
0 0.94 0 1.32 0 0.71 0 0.81 0 % Ash 0.44 0.45 0.57 0.57 0.50 0.51
0.72 0.73 0.68 0.68 % Volatile 80.00 80.58 80.14 80.90 79.98 81.06
77.67 78.23 79.32 79.97 Matter % Fixed 18.84 18.97 18.35 18.53
18.20 18.43 20.90 21.04 19.19 19.35 Carbon % Sulphur 0.03 0.03 0.08
0.08 0.04 0.04 0.13 0.13 0.04 0.04 Calorific Value (Gross) Btu/lb
10983 11062 11088 11194 10951 11098 11318 11399 10892 10981 Kcal/kg
6102 6146 6160 6219 6084 6166 6288 6333 6051 6100 GJ/T 25.55 25.73
25.79 26.04 25.47 25.81 26.33 26.51 25.33 25.54 % Carbon 59.57
60.00 60.01 60.58 59.50 60.30 60.64 61.07 59.18 59.66 % Nitrogen
0.15 0.15 0.13 0.13 0.16 0.16 0.16 0.16 0.16 0.16 % Oxygen 32.19
32.42 31.27 31.57 31.59 32.01 30.72 30.94 32.30 32.58 *"% Moisture"
refers to the amount of water in the samples immediately after the
torrefaction process (i.e., after drip drying for 5 minutes).
Example 13
Materials and Methods
[0156] A small scale torrefusion reactor was constructed in order
to test the continuous/semi-continuous process disclosed herein.
The reactor consists of a conveyor belt that can continuously or
semi-continuously convey pellets through combustible liquid held in
a large metal tank. The combustible liquid was heated with a
temperature control. The pellets were delivered onto the conveyor
belt of the reactor, where a hopper would be located, and then
conveyed along the conveyor belt into, through and then out of the
combustible liquid. The reactor is shown in FIG. 19.
Results
[0157] The reactor shown in FIG. 19 was used to torrefy wood
pellets and demonstrated that a continuous/semi-continuous process
could be used to torrefy pellets. Densified pellets were delivered
onto the conveyor belt in hot combustible liquid (on the right-hand
side of FIG. 19) and conveyed through the combustible liquid and
out the other end (i.e., on the left-hand side of FIG. 19). The
pellets were fully submersed as they conveyed along the conveyor
belt through the combustible liquid and were delivered on the other
end as a torrefied densified biomass.
* * * * *