U.S. patent application number 14/778938 was filed with the patent office on 2016-02-25 for method & apparatus for producing biochar.
The applicant listed for this patent is DIACARBON TECHNOLOGIES INC.. Invention is credited to Daniel Lennart Ericsson, Jerry Daniel Ericsson, Jared Luke Taylor.
Application Number | 20160053182 14/778938 |
Document ID | / |
Family ID | 51579246 |
Filed Date | 2016-02-25 |
United States Patent
Application |
20160053182 |
Kind Code |
A1 |
Ericsson; Jerry Daniel ; et
al. |
February 25, 2016 |
Method & Apparatus for Producing Biochar
Abstract
The present disclosure provides, at least in part, a system for
pyrolysis of biomass, the system comprising: (a) a reactor having a
retort extending therethrough, said retort comprising a conveyor,
an inlet, and an outlet; the reactor further comprising at least
one thermosensor, the thermosensor capable of generating a signal
when the temperature is above optimal levels; (b) a heating system
adapted to heat the reactor; (c) a syn-gas management system; the
management system comprising a syn-gas storage tank having an inlet
and an outlet, said inlet in fluid communication with the reactor,
and said outlet in fluid communication with the heating system and
syn-gas outlet such as a flare or storage tank wherein the
communication is controlled via a valve configurable between at
least a first position where flow is directed to the heating system
and a second position where flow is directed to the flare pipe; and
(d) a controller in communication with the thermosensor and the
valve; wherein the controller switches the valve from the first
position to the second position upon receiving a signal from the
thermosensor that the temperature in the reactor is above optimal
levels.
Inventors: |
Ericsson; Jerry Daniel;
(Vancouver, CA) ; Ericsson; Daniel Lennart;
(Vancouver, CA) ; Taylor; Jared Luke; (Vancouver,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DIACARBON TECHNOLOGIES INC. |
Burnaby |
|
CA |
|
|
Family ID: |
51579246 |
Appl. No.: |
14/778938 |
Filed: |
March 20, 2014 |
PCT Filed: |
March 20, 2014 |
PCT NO: |
PCT/CA2014/050298 |
371 Date: |
September 21, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61803739 |
Mar 20, 2013 |
|
|
|
Current U.S.
Class: |
201/20 ; 202/117;
202/118 |
Current CPC
Class: |
B01J 2219/002 20130101;
Y02E 50/15 20130101; C10L 9/083 20130101; C10B 47/44 20130101; B01J
8/008 20130101; Y02E 50/30 20130101; B01J 2219/00058 20130101; C10L
2290/02 20130101; C10B 53/02 20130101; C10L 2290/50 20130101; B01J
2208/00274 20130101; C10B 37/04 20130101; Y02E 50/10 20130101; C10B
41/08 20130101; C10L 2290/30 20130101; B01J 8/10 20130101; Y02E
50/14 20130101; C10B 21/10 20130101; C10L 2200/0469 20130101; C10B
57/06 20130101; C10B 41/00 20130101; C10L 5/447 20130101; B01J
2219/00225 20130101; C10B 27/06 20130101; C10B 7/00 20130101; C10L
2290/08 20130101; C10B 7/10 20130101 |
International
Class: |
C10B 53/02 20060101
C10B053/02; C10B 7/10 20060101 C10B007/10; C10B 57/06 20060101
C10B057/06; C10B 21/10 20060101 C10B021/10; C10B 37/04 20060101
C10B037/04; C10L 5/44 20060101 C10L005/44; C10B 41/00 20060101
C10B041/00 |
Claims
1. A system for pyrolysis of biomass, the system comprising: a
reactor comprising at least one retort extending therethrough, said
retorts comprising a conveyor, an inlet, and an outlet; the reactor
further comprising at least one thermosensor, the thermosensor
capable of generating a signal when the temperature is above a
predetermined value; a heating system adapted to heat the reactor;
a syn-gas management system; the management system comprising a
syn-gas storage tank having an inlet and an outlet, said inlet in
fluid communication with the reactor, and said outlet in fluid
communication with the heating system and a syn-gas outlet wherein
the communication is controlled via a valve configurable between a
first position where flow is directed to the heating system and a
second position where flow is directed to the flare pipe; and a
controller in communication with the thermosensor and the valve;
wherein the controller switches the valve from the first position
to the second position upon receiving a signal from the
thermosensor that the temperature in the reactor is above a
predetermined value.
2. A system for pyrolysis of biomass, the system comprising: a
reactor having a retort extending therethrough, said retort
comprising a conveyor, an inlet, and an outlet; the reactor further
comprising at least one thermosensor, the thermosensor capable of
generating a signal when the temperature is below a predetermined
value; a heating system adapted to heat the reactor; a syn-gas
management system; the management system comprising a syn-gas
storage tank having an inlet and an outlet, said inlet in fluid
communication with the reactor, and said outlet in fluid
communication with the heating system and a syn-gas outlet wherein
the communication is controlled via a valve configurable between at
least a first position where flow is directed to the heating system
and a second position where flow is directed to the flare pipe; and
a controller in communication with the thermosensor and the valve;
wherein the controller switches the valve from the second position
to the first position upon receiving a signal from the thermosensor
that the temperature in the reactor is below a predetermined
value.
3. The system of claim 1 or 2 comprising a dryer for drying the
biomass prior to entry into the reactor.
4. The system of claim 1 or 2 comprising a biochar delivery system
for receiving the biochar from the reactor.
5. The system of claim 4 wherein the biochar delivery system
comprises a cooling zone, a compaction area, with a rotary airlock
valve therebetween.
6. The system of claim 1 or 2 comprising an additive delivery
system for introducing additives to the biochar.
7. The system of claim 4-6 wherein the additive delivery system is
located with the biochar delivery system.
8. The system of claim 1 or 2 wherein the controller is a
programmable logic controller.
9. The system of claim 1 or 2 wherein the controller further
controls the speed of the conveyor.
10. The system of any of claims 1-9 wherein the conveyor is an
auger.
11. A method for converting biomass to biochar, the method
comprises the steps of: introducing biomass to an interior of a
retort in a reactor, the heated reactor; advancing the biomass
through the retort by means of a retort conveyor extending
therethrough, the temperature of the retort being elevated to a
point where pyrolysis of the biomass occurs; collecting biochar
from the retort; and applying a additive to the biochar.
12. The method of claim 11 wherein the additive is selected from
soil nutrients and/or minerals.
13. The method of claim 11 wherein the additive is selected from
nitrogen, sulphur, magnesium, calcium, phosphorous, potassium,
iron, manganese, copper, zinc, boron, chlorine, molybdenum, nickel,
cobalt, aluminum, silicon, selenium, sodium, compost tea, humic
acids, fulvic acids, plant hormones, pH conditioners, buffers, or
combinations thereof.
14. A modular pyrolysis apparatus, comprising: a reactor module
comprising at least one retort comprising a conveyor, an inlet, and
an outlet; at least one thermosensor; and a heating system adapted
to heat the reactor; a syn-gas management module comprising a
syn-gas storage tank, and a valve configurable between at least a
first and a second position; a control module comprising a
controller adapted to communicate with the thermosensor and the
valve.
15. The apparatus of claim 14 wherein a syn-gas management module
additionally comprises a condenser and a bio-oil storage tank.
16. The apparatus of claim 14 wherein the controller is a
programmable logic controller.
17. The apparatus of claim 14 wherein the controller further
controls the speed of the conveyor.
Description
FIELD
[0001] The present disclosure provides a system and method for
producing biochar from biomass. In particular, the present
disclosure provides pyrolytic systems and methods of producing
biochar.
BACKGROUND
[0002] There is an increasing interest in fuel derived from biomass
such as forestry, agricultural products or waste. There are various
technologies for converting biomass to fuel such as direct burning,
co-firing, gasification, fermentation, pyrolysis, and the like.
Depending on the feedstock and the process used the resultant
product will have different utilities and properties. In many
cases, it is desired to produce a product to replace a fossil fuel
leading to sustainability and environmental benefits.
[0003] Pyrolysis is a type of thermal decomposition in which a
substance is heated in the absence of oxygen, or under limited
oxygen conditions. Pyrolysis may be termed `fast` or `slow`
depending on the heating rate and residence time of the biomass. In
the case of dried biomass, the pyrolysis can result in
decomposition into three major products: bio-char (also known as
biochar or biocoal), bio-oil, and syn-gas. The development of
efficacious technology that enables the pyrolytic conversion of
lower-value biomass into higher energy bio-fuels and products
(bio-char/bio-coal and bio-oil) is desirable. In particular, it is
of interest to provide technology for the production, optimization,
and delivery of bio-fuels, particularly biochar, to be used in
various agricultural, forestry, and industrial applications that
can benefit from using renewable fuel sources
[0004] Pyrolysis for the conversion of biomass into fuel products
are described, for example, in CA 2,242,279 which discloses an
apparatus for continuous charcoal production; which CA 2,539,012
discloses a closed retort charcoal reactor system; CA 2,629,417
which discloses systems and methods for the continuous production
of charcoal by pyrolysis of organic feed.
[0005] Although pyrolysis systems are known, to date they have met
with limited commercial success. Several factors can affect the
utility of such systems including the availability, moisture
content and cost to transport the feedstock. As well as the
efficiency, robustness and flexibility of the system.
[0006] It would be advantageous to have a relatively inexpensive,
transportable and/or modular pyrolysis system for producing
biochar. The system may be simple, robust and/or flexible enough to
handle a variety of locations, feedstocks and conditions.
SUMMARY
[0007] The disclosure provides, at least in part, a system for
producing biochar from biomass. The present systems may be modular
comprising, for example, a reactor module and a syn-gas management
module.
[0008] As used herein, the term `biomass` refers to material
derived from non-fossilized organic material, including plant
matter such as lignocellulosic material and animal material such as
wastes, suitable for conversion into biofuels.
[0009] As used herein, the term `pyrolysis` refers to thermal
decomposition in which a substance is heated in the absence of
substantial amounts of oxygen.
[0010] As used herein, the term `biochar` or `biocoal` refers to
pyrolyzed biomass. Generally bio-char will have a calorific value
of about 15 MJ/Kg or greater, such as about 17 MJ/Kg or greater, or
about 19 MJ/Kg or greater, about 21 MJ/Kg or greater, about 23
MJ/Kg or greater, about 25 MJ/Kg or greater, about 27 MJ/Kg or
greater, about 29 MJ/Kg or greater.
[0011] As used herein, "a" or "an" means "one or more".
[0012] This summary does not necessarily describe all features of
the invention. Other aspects, features and advantages of the
invention will be apparent to those of ordinary skill in the art
upon review of the following description of specific embodiments of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the accompanying drawings, which illustrate one or more
exemplary non-limiting embodiments:
[0014] FIG. 1 shows a general flow diagram of an exemplary biomass
pyrolysis system according to the present disclosure;
[0015] FIG. 2 shows a schematic of a biomass pyrolysis system;
[0016] FIG. 3 shows the phases of biomass decomposition due to
increasing temperature (a) and a typical mass loss profile of
biomass undergoing pyrolysis (b).
DETAILED DESCRIPTION
[0017] The present disclosure provides, at least in part, a system
for pyrolysis of biomass, the system comprising: [0018] (a) a
reactor having a retort extending therethrough, said retort
comprising a suitable conveyor such as, for example, an auger or
paddle conveyor, an inlet, and an outlet; the reactor further
comprising at least one thermosensor, the thermosensor capable of
generating a signal when the temperature is above optimal levels;
[0019] (b) a heating system adapted to heat the reactor; [0020] (c)
a syn-gas management system; the management system comprising a
syn-gas storage tank having an inlet and an outlet, said inlet in
fluid communication with the reactor, and said outlet in fluid
communication with the heating system and a syn-gas outlet such as
a flare or storage tank wherein the communication is controlled via
a valve configurable between at least a first position where flow
is directed to the heating system and a second position where flow
is directed to the syn-gas outlet; and [0021] (d) a controller in
communication with the thermosensor and the valve; wherein the
controller switches the valve from the first position to the second
position upon receiving a signal from the thermosensor that the
temperature in the reactor is above optimal levels.
[0022] The present disclosure provides, at least in part, a system
for pyrolysis of biomass, the system comprising: [0023] (a) a
reactor having a retort extending therethrough, said retort
comprising a suitable conveyor such as, for example, an auger or
paddle conveyor, an inlet, and an outlet; the reactor further
comprising at least one thermosensor, the thermosensor capable of
generating a signal when the temperature is below optimal levels;
[0024] (b) a heating system adapted to heat the reactor; [0025] (c)
a syn-gas management system; the management system comprising a
syn-gas storage tank having an inlet and an outlet, said inlet in
fluid communication with the reactor, and said outlet in fluid
communication with the heating system and a syn-gas outlet such as
a flare or storage tank wherein the communication is controlled via
a valve configurable between at least a first position where flow
is directed to the heating system and a second position where flow
is directed to the syn-gas outlet; and [0026] (d) a controller in
communication with the thermosensor and the valve; wherein the
controller switches the valve from the second position to the first
position upon receiving a signal from the thermosensor that the
temperature in the reactor is below optimal levels.
[0027] The present thermosensor may be capable of generating a
signal when the temperature is above and below optimal levels. The
temperature value at above or below which the thermosensor
generates a signal may be predetermined. Such value may be altered
depending on a variety of factors such as the needs of a particular
production run, the feedstock, the output desired, or the like.
[0028] The bio-char produced via the present process may have a
calorific value of about 18 MJ/Kg or greater, about 22 MJ/Kg or
greater, about 24 MJ/Kg or greater, about 26 MJ/Kg or greater,
about 28 MJ/Kg or greater, about 30 MJ/Kg or greater. The present
bio-char may have an energy density of about 4 MEL or greater,
about 6 MEL or greater, about 8 MEL or greater, about 10 MEL or
greater.
[0029] The present bio-char may be hydrophobic. For example, if
processed at temperatures under about 400.degree. C. the bio-char
may be hydrophobic. The present bio-char may be hydrophilic. For
example, if processed at temperatures above about 400.degree. C.
the bio-char may be hydrophilic. For example, the present bio-char
may have a water contact angle ranging from about 102.degree. to
about 20.degree. depending on process temperature.
[0030] The present biochar preferably is grindable. The coal
industry uses the Hardgrove Grindability Index ("HGI") as a
standard test to measure grindability where samples are compared to
a standard reference sample ("SRS"). For example, if the
grindability of a sample was equal to the SRS coal, it would score
50. A score of less than 50 would indicate a sample is harder to
grind and a score of greater than 50 would indicate is easier. The
present biochar preferably has a HGI of about 50 or greater, about
52 or greater, about 54 or greater, about 56 or greater, about 58
or greater, about 60 or greater.
[0031] The present disclosure provides a reactor for converting
biomass into biochar. The reactor has at least one retort extending
through it. For example, the reactor may have two, three, four, or
more retorts. It is preferred that the reactor have at least four
retorts. The retort may comprise a suitable conveyor such as, for
example, an auger or paddle conveyor, an inlet and an outlet. The
inlet receives biomass which passes through the reactor on the
auger to the outlet.
[0032] The reactor further comprises a heating system which heats
the biomass as it passes through the reactor. The heating system
can heat the biomass to a temperature suitable to cause pyrolysis
of biomass. The heating system may be any suitable design such as,
for example, a plurality of heating elements, heat exchangers, or
burners throughout the length of the reactor.
[0033] The reactor comprises one or more thermosensors. The
thermosensors may be used to monitor the temperature of within the
reactor enabling the temperature to be kept at the appropriate
level to achieve the desired result. Multiple sensors may allow for
more accurate assessment of the temperature at different points in
the reactor. For example, based on the temperature reading the
heating may be increased or decreased.
[0034] Certain exemplary embodiments of the present disclosure
comprise one or more additional sensors such as, for example, a
sensor for sensing the speed of the auger. This sensor enables the
controller to assess the speed with which the biomass is moving
through the retort. If this speed is too slow the controller may
cause the speed to increase or if the speed is too fast the
controller may cause the speed to decrease.
[0035] In certain exemplary embodiments of the present disclosure,
the reactor produces a biochar stream and a gaseous stream. Biochar
can have utility as a fuel source, soil additive, or the like. The
gaseous stream may comprise condensable and non-condensable
components. The condensable components may, for example, be
condensed to form pyrolysis oil (bio-oil). Bio-oil may be used as a
petroleum substitute. The non-condensable gases (syn-gas) may be
combustible and used, for example, to fuel the reactor heating
system. The biochar stream may exit the reactor via a biochar
delivery system such as described further herein. The gaseous
stream may exit the reactor via a gas collection system such as
described further herein.
[0036] The present system may comprise a biochar delivery system
for receiving the biochar exiting the reactor. The delivery system
receives the biochar stream from the retort via the outlet. The
system may include a char cooling means. Any suitable cooling means
may be used such as direct contact with a cooling medium, indirect
contact with a cooling medium, direct contact fluid quenching, or
the like. For example, the means may be an auger which moves the
hot biochar through a cooling zone to compaction and/or bagging
area. An airlock such as a rotary valve airlock may be positioned
between the cooling zone and the compaction/bagging area. The
cooling of the biochar may be aided by the application of a liquid
such as water.
[0037] It is possible enrich the biochar with additives such as
nutrients or minerals. The resultant biochar could derive
advantageous properties from such enrichment. For example, when
used as a soil additive the addition of nutrients and minerals
markedly improves the performance of the product. Examples of
minerals include, but are not limited to, nitrogen, sulphur,
magnesium, calcium, phosphorous, potassium, iron, manganese,
copper, zinc, boron, chlorine, molybdenum, nickel, cobalt,
aluminum, silicon, selenium, or sodium. Examples of nutrients
include compost tea, humic and fulvic acids, plant hormones, and
other solutions of benefit to plant growth and soil health such as
buffers, pH conditioners, and the like.
[0038] The addition of the additives to the bio-char may be
achieved in any suitable manner. For example, additives may be
applied at the biochar delivery system. Additives can be introduced
to the cooling liquid and applied to the biochar at the cooling
zone. As the cooling liquid boils off the additives can be left
behind on the char. Additives may be introduced as a solid and, for
example, incorporated through mixing in the cooling zone.
[0039] Gases may exit the retort(s) via a gas collection system.
The system may be in any suitable form but can advantageously be a
series of pipes dispersed throughout the reactor such that gas
developed in the retort(s) during the pyrolysis process enters the
pipes and is carried out of the reactor. Where the reactor
comprises more than one retort it is preferred that each retort
have a separate gas collection pipe. Each retort may have more than
one gas collection pipe. The separate pipes may feed into a gas
collection module but it has been found that having separate pipes
running from a section of the retort that has been shown to
correspond with a particular biomass temperature and thermochemical
stage of decomposition (see FIG. 3) to a common gas manifold
improves efficiency of gas collection and reduces reactor downtime.
The specific positioning of these separate pipes along the retort
can improve efficiency.
[0040] The reactor comprising one or more retorts, one or more
thermosensors, and a heating system may be in the form of a module.
This can aid in the transportation of the pyrolysis system to
various locations. The reactor module may also comprise a gas
collection system.
[0041] The present system comprises a syn-gas management system.
The system is adapted to receive the gaseous stream from the
reactor, for example via the gas collection system. The gaseous
stream may comprise condensable components. The syn-gas management
system may comprise a condenser to remove at least some of the
condensable components to form bio-oil. The resultant oil may be
stored in one or more bio-oil storage tanks. The system may
comprise a pump such as, for example, a pump capable of creating at
least a partial vacuum. The pump may be positioned downstream of
the reactor, but upstream of the syn-gas and bio-oil collection
tanks to facilitate gas movement from retort to collection tanks
and combustion burners. The pump may take various forms, but will
preferably be capable of conveying a corrosive, and high
temperature gas stream. The pump may be a liquid-ring pump, a
positive displacement pump, or any other suitable pump or
combination of pumps. Preferred are pumps able to tolerate a
temperature greater than about 0.degree. C., a temperature greater
than about 50.degree. C., a temperature greater than about
100.degree. C. Suitable pumps may be able to tolerate a temperature
of less than about 600.degree. C. The pump preferably delivers a
pressure greater than about zero (0), but less than about two (2)
pounds per square inch when measured at the tank or at the
burner.
[0042] The syn-gas may be stored in a syn-gas tank. The storage
tank may have an inlet for receiving the flow of syn-gas from the
reactor and an outlet in fluid communication with the heating
system and a flare pipe or other means for discharging the syn-gas.
The communication may be controlled via a valve, such as a
three-way valve, configurable between a first position where flow
is directed to the heating system and a second position where flow
is directed to the flare pipe or other discharge means.
Alternatively the second position may direct the flow of gas to a
storage tank for later use.
[0043] The syn-gas management system comprising the syn-gas storage
tank, optionally the condenser and bio-oil storage tank may be in
the form of a module. This aids in the transportation of the
pyrolysis system to different locations and improves the ease of
implementation.
[0044] The present system may comprise a controller, such as for
example a programmable logic controller. The controller may be in
communication with the thermosensor and the valve. The controller
switches the valve from the first position to the second position
upon receiving a signal from the thermosensor that, for example,
the temperature in the reactor is above optimal levels. The
controller may also switch the valve from the second to the first
position upon receiving a signal from the thermosensor that, for
example, the temperature in the reactor is below optimal levels.
The controller will frequently be a microprocessor. The controller
may be a separate module or may be a part of one of the other
modules. As a separate module the controller can be located remote
from the pyrolysis system. The controller may control more than
just the valve. Depending on the particular embodiment the
controller may control a variety of factors such as, for example,
the delivery of biomass feedstock from the dryer to reactor, the
residence time of biomass in each retort, the speed and/or pressure
of vacuum pump(s), the residence time of biochar or bio-coal in any
cooling portion of the system, the amount of additive added to
biochar or biocoal, the speed of the retort, the speed of the
conveyor, or the like, or any combination thereof.
[0045] The present system may include a biomass dryer module. The
drying can receive biomass feedstock and may comprise a moisture
sensor. The dryer receives biomass and dries it to reduce the
moisture content. Preferably, the moisture content is about 20% or
less, about 18% or less, about 15% or less. The dryer may be, for
example, a flash dryer, a belt dryer, or a drum dryer. Once the
desired moisture content is reached the biomass can be fed into the
retort via the inlet means. A rotary valve airlock may be used
between the dryer and the reactor in order to control the delivery
of the biomass. In an embodiment of the present disclosure hot air
from the reactor can be used in the dryer thus reducing the need
for external heat sources in the dryer and improving the overall
efficiency of the system.
[0046] Any suitable biomass feedstock may be used herein such as,
for example, those comprising wood fibre, agricultural fibre,
by-products or waste (from plant or animal sources), municipal
waste, or the like. The selection of biomass may vary depending on
availability, the desired output and the particular application.
Softwood-fibre typically comprises three major components:
hemicellulose (25-35% dry mass), cellulose (40-50% dry mass), and
lignin (25-35% dry mass). The energy content of wood fibre is
typically 17-21 GJ/tonne on a dry basis.
[0047] The feedstock may be in particulate form and may have an
average particle size of from about 1 mm to about 50 mm, such as
from about 5 mm to about 25 mm. It is preferred that the feedstock
have a moisture content of about 15% or less, such as about 10% or
less, before commencement of pyrolysis.
[0048] Depending on the nature of the biomass it may be necessary
to prepare the feedstock prior to pyrolysis. For example, the
certain feedstocks may require grinding to produce particles of an
appropriate particle size and/or shape. The present method may
comprise a moisture removal step where the feedstock is heated to
such a temperature that moisture is driven off.
[0049] The present disclose provides a method of producing
bio-char. FIGS. 3a and 3b summarizes the steps that may be present
in said method. For instance, the present method may comprise a
hemicellulose decomposition step. The hemicellulose decomposition
step may be at a temperature of from about 200.degree. C. to about
280.degree. C., such as about 220.degree. C. to about 260.degree.
C. The temperature may vary throughout the step or may stay
constant. For example, the temperature may be increased at a rate
of about 100.degree. C./min or less, about 50.degree. C./min or
less, about 35.degree. C./min or less, about 20.degree. C./min or
less, about 15.degree. C./min or less, about 10.degree. C./min or
less. The step may continue for any suitable length of time such
as, about 1 minute or more, about 2 minutes or more, about 3
minutes or more, about 4 minutes or more, about 5 minutes or more,
about 10 minutes or more. It is preferred that by the end of the
pyrolysis at least about 30%, at least about 40%, at least about
50%, at least about 60%, at least about 70%, at least about 75%, at
least about 80%, at least about 85%, of the mass of hemicellulose
in the feedstock has been decomposed.
[0050] The present method may comprise a cellulose decomposition
step. The cellulose decomposition step may be at a temperature of
from about 240.degree. C. to about 400.degree. C., such as about
300.degree. C. to about 380.degree. C. The temperature may vary
throughout the step or may stay constant. For example, the
temperature may be increased at a rate of about 100.degree. C./min
or less, about 50.degree. C./min or less, about 35.degree. C./min
or less, about 20.degree. C./min or less, about 15.degree. C./min
or less, about 10.degree. C./min or less. The step may continue for
any suitable length of time such as, about 1 minute or more, about
2 minutes or more, about 3 minutes or more, about 4 minutes or
more, about 5 minutes or more, about 10 minutes or more. It is
preferred that by the end of the pyrolysis at least about 30%, at
least about 40%, at least about 50%, at least about 60%, at least
about 70%, of the mass of cellulose in the feedstock has been
decomposed.
[0051] The present method may comprise a lignin decomposition step.
The cellulose decomposition step may be at a temperature of from
about 280.degree. C. to about 500.degree. C., such as about
400.degree. C. to about 500.degree. C. The temperature may vary
throughout the step or may stay constant. For example, the
temperature may be increased at a rate of about 100.degree. C./min
or less, about 50.degree. C./min or less, about 35.degree. C./min
or less, about 20.degree. C./min or less, about 15.degree. C./min
or less, about 10.degree. C./min or less. The step may continue for
any suitable length of time such as, about 1 minute or more, about
2 minutes or more, about 3 minutes or more, about 4 minutes or
more, about 5 minutes or more, about 10 minutes or more. It is
preferred that by the end of the pyrolysis at least about 5%, at
least about 10%, at least about 15%, at least about 20%, of the
mass of lignin in the feedstock has been decomposed.
[0052] Yields of bio-char, bio-oil, and syn-gas can be altered by
varying the process temperatures and/or heat transfer rates. While
not wishing to be bound by theory, it is believed that higher
temperatures tend to favour the production of bio-oil and/or
syn-gas by driving off more of the condensable volatiles produced
from decomposition of cellulose. Conversely, slow pyrolysis may
favour the production of bio-char by limiting the decomposition of
cellulose and reducing the amount of bio-oil produced. Bio-coal
production can generally be maximized at temperatures of
approximately 285.degree. C. It is believed that at these
temperatures hemicellulose still decomposes into syn-gas while much
of the cellulose remains as a solid within the lignin matrix. By
limiting the decomposition of the cellulose fraction, yields of
bio-coal can be increased to around 70%. This type of pyrolysis is
known as torrefaction and the resulting bio-char is referred to
torrefied bio-char or bio-coal. Producing torrefied bio-char leads
to a reduced amount of bio-oil thus reducing the issues associated
with storing and handling such oil. In addition, many industrial
scale kilns are already equipped to handle solid fuels such as
bio-coal rather than liquid bio-oil.
[0053] Certain embodiments according to the present disclosure may
provide bio-char yields in the range of from about 20% to about
80%, such as about 25% to about 70%. In general, higher yields are
seen with torrefaction than with other types of pyrolysis. Certain
embodiments according to the present disclosure may provide bio-oil
yields in the range of from about 10% to about 40%, such as about
20% to about 50%.
[0054] According to a further aspect of the invention, a method for
converting biomass to biochar is provided. The method comprises the
steps of: [0055] (a) introducing biomass to an interior of a retort
in a reactor; [0056] (b) advancing the biomass through the retort
by means of a retort conveyor such as an auger extending
therethrough, the temperature of the retort being elevated to a
point where pyrolysis of the biomass occurs; [0057] (c) collecting
biochar from the retort; [0058] (d) applying an additive to the
biochar; wherein the additive is selected from soil nutrients
and/or minerals. Examples of minerals include, but are not limited
to, nitrogen, sulphur, magnesium, calcium, phosphorous, potassium,
iron, manganese, copper, zinc, boron, chlorine, molybdenum, nickel,
cobalt, aluminum, silicon, selenium, sodium, compost tea, humic
acids, fulvic acids, plant hormones, pH conditioners, buffers, or
combinations thereof.
[0059] Referring to FIG. 1, a general flow diagram of an exemplary
biomass pyrolysis system can be seen. Biomass 1 is loaded into a
dryer system 2. Biomass may be any suitable such as wood waste,
agricultural waste, or any other organic material that can be used
to produce bio-char. A rotary valve airlock 3 controls the feeding
of the dry biomass feed into a reactor 4. The reactor produces a
biochar stream which is fed to a cooling zone 5. Cooling water 6
and additives 7 may be applied to the biochar. A rotary valve
airlock 8 controls the movement of the cooled biochar to the
compaction 9 and bagging 10 areas.
[0060] The reactor produces a gaseous stream which passes to a
condenser 11 which can condense condensable components such as
bio-oil. The condensed bio-oil is collected in a bio-oil collection
tank 12. A vacuum pump 13 moves the remain gaseous stream to a oil
tank 14, a syn-gas collection tank 15. The gaseous stream is fed to
a three-way valve 16. A controller 18 receives a signal from a
thermosensor (not shown) in the reactor 4. Depending on the needs
of the reactor the controller 18 can direct the valve via a control
signal 19 to direct the syn-gas to a flare 17 or to the reactor 4
where the syn-gas can be burnt by a furnace (not shown).
[0061] Referring to FIG. 2, an overall side view of a biomass
reactor system according to an embodiment of the present disclosure
can be seen. Feedstock hopper 1 loads biomass into a cyclone dryer
system 2 which has an exhaust 3. Hot flue gas 5 from the furnace 6
can be used in the dryer assembly. A rotary valve airlock 4
controls the feeding of biomass feed into one or more anaerobic
retorts 7. Biomass may be wood waste, agricultural waste, or any
other organic material that can be burned to produce heat energy.
Retorts 7 are tubular and extend through furnace 6. The biomass is
advanced through retorts 7 by augers. Heat from furnace 6 and the
anaerobic conditions in retorts 7 pyrolize the biomass advancing
through retorts 7, converting the organic feed to form a biochar
stream and a gaseous stream.
[0062] At least a portion of the gaseous stream is collected by the
gas collection system 8 which comprises pipes leading to a gas
collection manifold. The gases are then fed into a condenser 10
which can condense condensable components such as bio-oil. The
condensed bio-oil is collected in a bio-oil collection tank 17
which the gaseous stream is fed to a three-way valve 19. Depending
on the needs of the furnace 6 the valve can direct the gas to a
flare 18 or to syn-gas burners 9 via syn-gas pipe 20.
[0063] Biochar at the downstream end of retorts 7 is collected and
delivered to a cooling retort with a water jacket and auger 13. The
assembly comprises a coolant (water) tank 11 and an additive tank
12. The water and/or additive are applied to the biochar via spray
nozzles 14. Cooled and improved biochar is the delivered to a
collection bin 16 controlled via a rotary valve airlock 15.
[0064] It is contemplated that the different parts of the present
description may be combined in any suitable manner. For instance,
the present examples, methods, aspects, embodiments or the like may
be suitably implemented or combined with any other embodiment,
method, example or aspect of the invention.
[0065] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as is commonly understood by one
of ordinary skill in the art to which this invention belongs.
Unless otherwise specified, all patents, applications, published
applications and other publications referred to herein are
incorporated by reference in their entirety. If a definition set
forth in this section is contrary to or otherwise inconsistent with
a definition set forth in the patents, applications, published
applications and other publications that are herein incorporated by
reference, the definition set forth in this section prevails over
the definition that is incorporated herein by reference. Citation
of references herein is not to be construed nor considered as an
admission that such references are prior art to the present
invention.
[0066] Use of examples in the specification, including examples of
terms, is for illustrative purposes only and is not intended to
limit the scope and meaning of the embodiments of the invention
herein. Numeric ranges are inclusive of the numbers defining the
range. In the specification, the word "comprising" is used as an
open-ended term, substantially equivalent to the phrase "including,
but not limited to," and the word "comprises" has a corresponding
meaning.
[0067] The invention includes all embodiments, modifications and
variations substantially as hereinbefore described and with
reference to the examples and figures. It will be apparent to
persons skilled in the art that a number of variations and
modifications can be made without departing from the scope of the
invention as defined in the claims. Examples of such modifications
include the substitution of known equivalents for any aspect of the
invention in order to achieve the same result in substantially the
same way.
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