U.S. patent number RE40,419 [Application Number 11/805,576] was granted by the patent office on 2008-07-01 for production of synthetic transportation fuels from carbonaceous material using self-sustained hydro-gasification.
This patent grant is currently assigned to The Regents of the University of California. Invention is credited to Colin E. Hackett, Joseph M. Norbeck.
United States Patent |
RE40,419 |
Norbeck , et al. |
July 1, 2008 |
Production of synthetic transportation fuels from carbonaceous
material using self-sustained hydro-gasification
Abstract
A process and apparatus for producing a synthesis gas for use as
a gaseous fuel or as feed into a Fischer-Tropsch reactor to produce
a liquid fuel in a substantially self-sustaining process. A slurry
of particles of carbonaceous material in water, and hydrogen from
an internal source, are fed into a hydro-gasification reactor under
conditions whereby methane rich producer gases are generated and
fed into a steam pyrolytic reformer under conditions whereby
synthesis gas comprising hydrogen and carbon monoxide are
generated. A portion of the hydrogen generated by the steam
pyrolytic reformer is fed through a hydrogen purification filter
into the hydro-gasification reactor, the hydrogen therefrom
constituting the hydrogen from an internal source. The remaining
synthesis gas generated by the steam pyrolytic reformer is either
used as fuel for a gaseous fueled engine to produce electricity
and/or process heat or is fed into a Fischer-Tropsch or similar
reactor under conditions whereby a liquid fuel is produced.
Inventors: |
Norbeck; Joseph M. (Riverside,
CA), Hackett; Colin E. (Riverside, CA) |
Assignee: |
The Regents of the University of
California (Oakland, CA)
|
Family
ID: |
27734515 |
Appl.
No.: |
11/805,576 |
Filed: |
February 4, 2003 |
PCT
Filed: |
February 04, 2003 |
PCT No.: |
PCT/US03/03489 |
371(c)(1),(2),(4) Date: |
June 28, 2005 |
PCT
Pub. No.: |
WO03/066517 |
PCT
Pub. Date: |
August 14, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
60355405 |
Feb 5, 2002 |
|
|
|
Reissue of: |
10503435 |
Jun 28, 2005 |
07208530 |
Apr 24, 2007 |
|
|
Current U.S.
Class: |
518/704;
48/127.1; 518/700; 518/705; 518/706; 518/702; 48/127.5; 423/650;
423/418.2 |
Current CPC
Class: |
C10J
3/721 (20130101); C10J 3/723 (20130101); C10J
3/54 (20130101); C10G 2/30 (20130101); C01B
3/34 (20130101); C10J 3/00 (20130101); C10J
3/66 (20130101); C10G 2/32 (20130101); C10G
1/002 (20130101); C01B 2203/00 (20130101); C10J
2300/165 (20130101); C01B 2203/146 (20130101); C10J
2300/0943 (20130101); C01B 2203/0233 (20130101); C01B
2203/1258 (20130101); C10J 2300/093 (20130101); C01B
2203/0894 (20130101); C01B 2203/04 (20130101); C10J
2300/0946 (20130101); Y02E 50/30 (20130101); C01B
2203/0833 (20130101); C01B 2203/1205 (20130101); C01B
2203/84 (20130101); C10J 2300/0916 (20130101); C10J
2300/1853 (20130101); C01B 2203/0883 (20130101); C01B
2203/1276 (20130101); C10J 2300/0966 (20130101); Y02P
20/145 (20151101); C01B 2203/148 (20130101); C10J
2300/0976 (20130101); C10J 2300/1675 (20130101); C10J
2300/06 (20130101); C01B 2203/062 (20130101); C10J
2300/1807 (20130101); C10J 2300/1253 (20130101); C10J
2300/1892 (20130101); C01B 2203/06 (20130101); C10J
2300/0973 (20130101); C10J 2300/1671 (20130101); C01B
2203/0495 (20130101); C10J 2300/1659 (20130101); Y02E
50/32 (20130101); Y02P 20/52 (20151101); C10J
2300/0903 (20130101); C10J 2300/092 (20130101); C10J
2300/0983 (20130101); C10J 2300/0906 (20130101); C10J
2300/0909 (20130101); C10J 2300/1693 (20130101); C01B
2203/0827 (20130101); C10J 2300/1884 (20130101); Y02E
20/16 (20130101); C01B 2203/0838 (20130101) |
Current International
Class: |
C07C
27/00 (20060101); C01B 3/24 (20060101); C01B
3/32 (20060101); C01B 31/18 (20060101) |
Field of
Search: |
;518/700-706
;423/418.2,650 ;48/127.1,127.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Olsen et al, Unit processes and principles of Chemical Engineering,
D.Van Nostrand Company, 1932, pp. 1-3. cited by examiner.
|
Primary Examiner: Parsa; J.
Attorney, Agent or Firm: Berliner & Associates
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of Provisional Patent
Application Ser. No. 60/355,405, filed Feb. 5, 2002.
Claims
What is claimed is:
1. A process for producing a synthesis gas for use as a gaseous
fuel or as feed into Fischer-Tropsch reactor to produce a liquid
fuel, the improvement comprising: forming a liquid suspension
slurry of particles of carbonaceous material in water; feeding said
suspension slurry and hydrogen from an internal source into a
hydro-gasification reactor under conditions of super-atmospheric
pressure without a reaction catalyst and at a temperature under
said pressure whereby methane rich producer gases are generated;
feeding the methane rich producer gases from the hydro-gasification
reactor into a steam pyrolytic reformer under conditions whereby
synthesis gas comprising hydrogen end carbon monoxide are
generated; feeding a portion of the hydrogen generated by the steam
pyrolytic reformer into the hydro-gasification reactor as said
hydrogen from an internal source; and either utilizing said
synthesis gas generated by the steam pyrolytic reformer for process
heat or as fuel for an engine to produce electricity, or feeding
said synthesis gas into the Fischer-Tropsch type reactor under
conditions whereby a liquid fuel is produced.
2. The process of claim 1 wherein said portion of the hydrogen
generated by the steam pyrolytic reformer is obtained through a
hydrogen purification filter.
3. The process of claim 1 wherein said conditions and the relative
amounts of said carbonaceous material, hydrogen and water in the
hydro-gasification reactor are such that said methane rich producer
gases are produced exothermally.
4. The process of claim 1 in which said liquid slurry of
carbonaceous material is formed by grinding said carbonaceous
material in water.
5. The process of claim 1 in which said liquid slurry of
carbonaceous material is heated with superheated steam from a steam
generator prior to being fed into the hydro-gasification
reactor.
6. The process of claim 5 in which the superheated steam is
separated from the slurry, prior to feeding the slurry into the
hydro-gasification reactor, and is fed into the steam pyrolytic
reformer to react with the methane rich producer gases from the
hydro-gasification reactor.
7. The process of claim 5 in which the slurry, together with the
superheated steam, is fed into the hydro-gasification reactor.
8. The process of claim 7 in which synthesis gas generated by the
steam pyrolytic reformer is fed into a Fischer-Tropsch reactor
under conditions whereby a liquid fuel is produced.
9. The process of claim 8 wherein said conditions and the relative
amounts of hydrogen and carbon monoxide in the Fischer-Tropsch
reactor are such that said liquid fuel is produced
exothermally.
10. The process of claim 9 comprising transferring exothermic heat
from one or both of the hydro-gasification reactor and
Fischer-Tropsch reactor to one or both of the steam generator and
the steam pyrolytic reformer.
11. The process of claim 9 comprising transferring exothermic heat
from the hydro-gasification reactor and Fischer-Tropsch reactor to
the steam generator and the steam pyrolytic reformer.
12. The process of claim 11 in which molten salt loops are used to
transfer said exothermic heat.
13. The process of claim 1 in which said carbonaceous material
comprises biomass.
14. The process of claim 13 in which said biomass comprises
municipal solid waste.
15. The process of claim 8 in which the relative amounts of
hydrogen and carbon monoxide in the synthesis gas fed into the
Fischer-Tropsch reactor are such that said liquid fuel is
substantially cetane.
16. A substantially self-sustaining process for producing a liquid
fuel from carbonaceous feed, comprising: grinding said carbonaceous
material in water to form a suspension slurry of carbonaceous
particles; heating the slurry with superheated steam from a steam
generator; feeding hydrogen from an internal source, the suspension
slurry, and the superheated steam into a hydro-gasification reactor
under conditions of a pressure of about 20 to 50 atmospheres
without a reaction catalyst and at a temperature in the range of
about 700 to 1200 degrees Celsius, and in amounts whereby methane
rich producer gases are generated exothermally; feeding the methane
rich producer gases from the hydro-gasification reactor and said
superheated steam into a steam pyrolytic reformer under conditions
whereby synthesis gas comprising hydrogen and carbon monoxide are
generated; feeding a portion of the hydrogen generated by the steam
pyrolytic reformer, obtained through a hydrogen purification
filter, into the hydro-gasification reactor, the hydrogen therefrom
constituting said hydrogen from an internal source; feeding the
remainder of the synthesis gas generated by the steam pyrolytic
reformer into the Fischer-Tropsch reactor under conditions whereby
a liquid fuel is produced exothermally; and transferring exothermic
heat from the hydro-gasification reactor and Fischer-Tropsch
reactor to the steam generator and the steam pyrolytic reformer,
whereby said process is substantially self-sustaining.
17. The process of claim 16 in which molten salt loops are used to
transfer said exothermic heat.
18. The process of claim 16 in which said carbonaceous material
comprises biomass.
19. The process of claim 16 in which said biomass comprises
municipal solid waste.
Description
STATEMENT REGARDING SPONSORED RESEARCH AND DEVELOPMENT
This invention was made with support from the City of Riverside.
The City of Riverside has certain tights to this invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the invention is the synthesis of transportation fuel
from carbonaceous feed stocks.
2. Description of Related Art
There is a need to identify new sources of chemical energy and
methods for its conversion into alterative transportation fuels,
driven by many concerns including environmental, health, safety
issues, and the inevitable future scarcity of petroleum-based fuel
supplies. The number of internal combustion engine fueled vehicles
worldwide continues to grow, particularly in the midrange of
developing countries. The worldwide vehicle population outside the
U.S., which mainly uses diesel fuel, is growing faster than inside
the U.S. This situation may change as more fuel-efficient vehicles,
using hybrid and/or diesel engine technologies, are introduced to
reduce both fuel consumption and overall emissions. Since the
resources for the production of petroleum-based fuels are being
depleted, dependency on petroleum will become a major problem
unless non-petroleum alternative fuels, in particular clean-burning
synthetic diesel fuels, are developed. Moreover, normal combustion
of petroleum-based fuels in conventional engines can cause serious
environmental pollution unless strict methods of exhaust emission
control are used. A clean burning synthetic diesel fuel can help
reduce the emissions from diesel engines.
The production of clean-burning transportation fuels requires
either the reformulation of existing petroleum-based fuels or the
discovery of new methods for power production or fuel synthesis
from unused materials. There are many sources available, derived
from either renewable organic or waste carbonaceous materials.
Utilizing carbonaceous waste to produce synthetic fuels is an
economically viable method since the input feed stock is already
considered of little value, discarded as waste, and disposal is
often polluting.
Liquid transportation fuels have inherent advantages over gaseous
fuels, having higher energy densities than gaseous fuels at the
same pressure and temperature. Liquid fuels can be stored at
atmospheric or low pressures whereas to achieve liquid fuel energy
densities, a gaseous fuel would have to be stored in a tank on a
vehicle at high pressures that can be a safety concern in the case
of leaks or sudden rupture. The distribution of liquid fuels is
much easier than gaseous fuels, using simple pumps and pipelines.
The liquid fueling infrastructure of the existing transportation
sector ensures easy integration into the existing market of any
production of clean-burning synthetic liquid transportation
fuels.
The availability of clean-burning liquid transportation fuels is a
national priority. Producing synthesis gases cleanly and
efficiently from carbonaceous sources, that can be subjected to a
Fischer-Tropsch process to produce clean and valuable synthetic
gasoline and diesel fuels, will benefit both the transportation
sector and the health of society. Such a process allows for the
application of current state-of-art engine exhaust after-treatment
methods for NO.sub.x reduction, removal of toxic particulates
present in diesel engine exhaust, and the reduction of normal
combustion product pollutants, currently accomplished by catalysts
that are poisoned quickly by any sulfur present, as is the case in
ordinary stocks of petroleum derived diesel fuel, reducing the
catalyst efficiency. Typically, Fischer-Tropsch liquid fuels,
produced from biomass derived synthesis gases, are sulfur-free,
aromatic free, and in the case of synthetic diesel fuel have an
ultrahigh cetane value.
Biomass material is the most commonly processed carbonaceous waste
feed stock used to produce renewable fuels. Waste plastic, rubber,
manure, crop residues, forestry, tree and grass cuttings and
biosolids from waster water (sewage) treatment are also candidate
feed stocks for conversion processes. Biomass feed stocks can be
converted to produce electricity, heat, valuable chemicals or
fuels. California tops the nation in the use and development of
several biomass utilization technologies. Each year in California,
more than 45 million tons of municipal solid waste is discarded for
treatment by waste management facilities. Approximately half this
waste ends up in landfills. For example, in just the Riverside
County, California area, it is estimated that about 4000 tons of
waste wood are disposed of per day. According to other estimates,
over 100,000 tons of biomass per day are dumped into landfills in
the Riverside County collection area. This municipal waste
comprises about 30% waste paper or cardboard, 40% organic (green
and food) waste, and 30% combinations of wood, paper, plastic and
metal waste. The carbonaceous components of this waste material
have chemical energy that could be used to reduce the need for
other energy sources if it can be converted into a clean-burning
fuel. These waste sources of carbonaceous material are not the only
sources available. While many existing carbonaceous waste
materials, such as paper, can be sorted, reused and recycled, for
other materials, the waste producer would not need to pay a tipping
fee, if the waste were to be delivered directly to a conversion
facility. A tipping fee, presently at $30-$35 per ton, is usually
charged by the waste management agency to offset disposal costs.
Consequently not only can disposal costs be reduced by transporting
the waste to a waste-to-synthetic fuels processing plant, but
additional waste would be made available because of the lowered
cost of disposal.
The burning of wood in a wood stove is an example of using biomass
to produce heat energy. Unfortunately, the open burning the biomass
waste to obtain energy and heat is not a clean and efficient method
to utilize the calorific value. Today, many new ways of utilizing
carbonaceous waste are being discovered. For example, one way is to
produce synthetic liquid transportation fuels, and another ways is
to produce energetic gases for conversion into electricity.
Using fuels from renewable biomass sources can actually decrease
the net accumulation of greenhouse gases, such as carbon dioxide,
while providing clean, efficient energy for transportation. One of
the principal benefits of co-production of synthetic liquid fuels
from biomass sources is that it can provide a storable
transportation fuel while reducing the effects of greenhouse gases
contributing to global warming. In the future, these co-production
processes could provide clean-burning fuels for a renewable fuel
economy that could be sustained continuously.
A number of processes exist to convert coal and other carbonaceous
materials to clean-burning transportation fuels, but they tend to
be too expensive to compete on the market with petroleum-based
fuels, or they produce volatile fuels, such as methanol and ethanol
that have vapor pressure values too high for use in high pollution
areas, such as the Southern California air-basin, without
legislative exemption from clean air regulations. An example of the
latter process is the Hynol Methanol Process, which uses
hydro-gasification and steam reformer reactors to synthesize
methanol using a co-feed of solid carbonaceous materials and
natural gas, and which has a demonstrated carbon conversion
efficiency of >85% in bench-scale demonstrations.
The need to identity new resources and methods for the production
of transportation fuels requires not only investigating
improvements in ways to produce current petroleum-based fuel but
also research into new methods for the synthesis of functionally
equivalent alternative fuels obtained using resources and methods
that are not in use today. The production of synthetic liquid fuels
from carbonaceous materials such as waste organic materials is one
way to solve these problems. The utilization of carbonaceous waste
materials to produce synthetic fuels can be considered a feasible
method of obtaining new resources for fuel production since the
material feed stock is already considered a waste without value and
often it's disposal creates additional sources of environmental
pollution.
SUMMARY OF THE INVENTION
The present invention makes use of steam pyrolysis,
hydro-gasification and steam reformer reactors to produce a
synthesis gas that can be converted into a synthetic paraffinic
fuel, preferably a diesel fuel, although synthetic gasolines and
jet propulsion fuels can also be made, using a Fischer-Tropsch
paraffin fuel synthesis reactor. Alternatively, the synthesis gas
may be used in a co-generated power conversion and process heat
system. The present invention provides comprehensive equilibrium
thermo-chemical analyses for a general class of co-production
processes for the synthesis of clean-burning liquid transportation
fuels, thermal process energy and electric power generation from
feeds of coal, or other carbonaceous materials, and liquid water.
It enables a unique design, efficiency of operation and
comprehensive analysis of coal, or any other carbonaceous feed
materials to co-produced fuel, power and heat systems.
The invention provides a process and apparatus for producing a
synthesis gas for use as a gaseous fuel or as feed into a
Fischer-Tropsch reactor to produce a liquid paraffinic fuel,
recycled water and sensible heat, in a substantially
self-sustaining process. A slurry of particles of carbonaceous
material suspended in liquid water, and hydrogen from an internal
source, are fed into a steam generator for pyrolysis and
hydro-gasification reactor under conditions whereby super-heated
steam, methane, carbon dioxide and carbon monoxide are generated
and fed into a steam reformer under conditions whereby synthesis
gas comprising primarily of hydrogen and carbon monoxide are
generated. Using a hydrogen separation filter for purification, a
portion of the hydrogen generated by the steam reformed is fed into
the hydro-gasification reactor as the hydrogen from an internal
source. The remaining synthesis gas generated by the steam reformer
is either used as fuel for a gaseous fueled engine or gas turbine
to produce electricity and process heat, or is fed into a
Fischer-Tropsch fuel synthesis reactor under conditions to produce
a liquid fuel, and recycled water. The correct stoichiometric ratio
of hydrogen to carbon monoxide molecules fed into the
Fischer-Tropsch fuel synthesis reactor, is controlled by the water
to carbon ratio in the feed stocks. Molten salt loops are used to
transfer heat from the exothermic hydro-gasification reactor (and
from the exothermic Fischer-Tropsch reactor if liquid fuel is
produced) to the exothermic steam generator for pyrolysis and the
steam reformer reactor vessels.
In particular, the present invention provides the following
features.
1) A general purpose solid carbonaceous material feed system that
can accept arbitrary combinations of coal, urban and agricultural
biomass, and municipal solid waste for hydro-gasification.
2) A first state, steam generator for pyrolysis and
hydro-gasification unit.
3) A steam reformer as a second stage reactor to produce hydrogen
rich synthesis gas from the output of the first stage steam
generator for pyrolysis and hydro-gasification unit. The molal
steam to carbon ratio is maintained as necessary to bring the
chemical reactions close to equilibrium;
4) Either (a) a Fischer-Tropsch (synthesis gas-to-liquid) fuel
synthesizer as a third and final stage reactor to convert the
synthesis gas from the steam reformer into a sulfur-free
clean-burning liquid transportation fuel, and recycled water or (b)
use of generated synthesis gas as fuel for process heat and/or in a
fuel engine or gas turbine that can generate electricity;
5) Three thermo-chemical process reactors are operated to produce
nearly pure paraffinic hydrocarbon liquids (similar to petroleum
derived diesel fuels) and was-like compounds (similar to petroleum
derived USP paraffinic jellies, which can be further refined into
more diesel-like fuels using conventional methods) from
carbonaceous feed stocks (such as waste wood) in a continuous
self-sustainable fashion without the need for additional fuels or
external energy sources. The reactor configurations can also be
optimized for the production of other synthetic fuels, such as
dimethyl ether (a fuel similar to propane, that can be used as a
transportation fuel in diesel engines and gas turbines) and gaseous
fuel grade hydrogen (a fuel that can be used in engines and
turbines, and if purified to remove carbon monoxide, as an
electrochemical fuel in a fuel cell), as well as energetic
synthesis gases for combined cycle power conversion and electric
power production.
The fundamental advantages of this invention, over what was
achievable with the prior art, are: (a) energy efficient (>85%)
methane production from the available carbon in the carbonaceous
feed stock using steam pyrolysis to activate the carbon and
hydrogen gas as the sole initiating reactant, in contradistinction
to partial oxidative gasification usually requiring an additional
energy intensive air separation system to provide the necessary
oxygen; (b) chemically self-sustained operation of the first stage
hydro-gasification reactor by feeding-back surplus hydrogen gas
produced in the second stage methane steam reformer reactor; (c)
energy efficient synthesis of clean-burning transportation fuels
using the effluent gases from the steam reformer, such as: (i)
paraffinic compounds using a third stage Fischer-Tropsch fuel
synthesis reactor, (ii) dimethyl ether synthesis using a third
stage synthesis reactor, and (iii) hydrogen production using a
hydrogen separation and/or purification filter without the need for
a third stage fuel synthesis reactor; (d) thermally self-sustained
operation of all reactors by effective management of thermal and
chemical energy using combinations of molten salt or water/steam
heat transfer fluids, combustion of product energetic gases to
start and maintain process temperatures, recovered process heat for
the generation of electric power, without the need for additional
fuels and external energy sources; (c) significantly reduced
airborne emissions from all enclosed processes reactors and/or
synthesis gas combustors when compared to direct naturally
aspirated combustion (usually known as open incineration) of the
carbonaceous feed materials; and f) the ability to capture all
gaseous carbon dioxide effluent from process reactors or
intra-process synthesis gas combustors for sequestration and/or
chemical conversion into condensed phase compounds using
conventional technologies.
These novel configurations of the process reactors have the
capability to improve the overall efficiency of energy utilization
for carbonaceous material conversion in a co-production plant for
synthetic fuels, chemicals and energy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow diagram showing the overall modeling of the
present invention;
FIG. 2 is a graph showing a plot of carbon conversion vs. H.sub.2/C
and H.sub.2O/C ratios at 800.degree. C. and 30 atm. in HPR;
FIG. 3 is a graph showing a plot of CH.sub.4/C feed ratio vs.
H.sub.2/C and H.sub.2O/C ratios at 800.degree. C. and 30 atm. in
HPR;
FIG. 4 is a graph showing a plot of CO.sub.2/C feed ratio vs.
H.sub.2/C and H.sub.2O/C ratio sat 800.degree. C. and 30 atm. in
HPR;
FIG. 5 is a graph showing a plot of CO/C feed ratio vs. H.sub.2/C
and H.sub.2O/C ratios at 800.degree. C. and 30 atm. in HPR;
FIG. 6 is a graph showing the effects of Temperature and Pressure
conditions on CO.sub.2/H ration the hydro-gasifier reactor (HGR) at
fixed feed of 2.629 moles of H.sub.2 and 0.0657 moles of H.sub.2O
per mole of C;
FIG. 7 is a graph showing the effect of Temperature and Pressure
conditions on CH.sub.4/H ratio in the HGR at fixed feed of 2.629
moles of H.sub.2 and 0.0657 moles of H.sub.2O per mole of C;
FIG. 8 is a graph showing the effect of Temperature and Pressure
conditions on H.sub.2/C ratio in the HGR at fixed feed of 2.629
moles of H.sub.2 and 0.0657 moles of H.sub.2O per mole of C;
FIG. 9 is a graph showing the effect of Temperature and Pressure
conditions on CO/H in the HGR at fixed feed of 2.629 moles of
H.sub.2 and 0.0657 moles of H.sub.2O per mole of C;
FIG. 10 is a graph showing the effect of input H.sub.2O/C ratio on
steam reformer (SPR) performance measure by the net H.sub.2/CO
ratio after H2 recycling for the HGR at 1000.degree. C. and 30
atm;
FIG. 11 is a graph shown the effect of changing the input
H.sub.2O/C ratio on SPR products, CO, CO.sub.2 and CH.sub.4 in the
SPR at 1000.degree. C. and 30 atm;
FIG. 12 is a graph showing the effect of Temperature and Pressure
conditions on H.sub.2/CO ratio in the SPR (2.76 moles of
H.sub.2O/mole of C added to the SPR);
FIG. 13 is a graph showing the effect of Temperature and Pressure
conditions on CH.sub.4/C ratio in the SPR (2.76 moles of
H.sub.2O/mole of C added to the SPR);
FIG. 14 is a diagram showing the Mass Flow Schematic of Biomass
Hydro-gasification for production of Fischer-Tropsch paraffin
fuels;
FIG. 15 is a diagram showing the Molal Flow Schematic of Biomass
Hydro-gasification for production of Fischer-Tropsch paraffin
fuels;
FIG. 16 is a diagram showing the Thermal Energy Management
Schematic of Biomass Hydro-gasification for production of
Fischer-Tropsch paraffin fuels;
FIG. 17 is a diagram showing the Water/Steam Flow Schematic of
Biomass Hydro-gasification for production of Fischer-Tropsch
paraffin fuels;
FIG. 18 is a diagram showing Molten Salt Flow Schematic of Biomass
Hydro-gasification for production of Fischer-Tropsch paraffin
fuels;
FIG. 19 is a diagram showing Mass Flow Schematic of Biomass
Hydro-gasification for production of dimethyl ether;
FIG. 20 is a diagram showing Mole Flow Schematic of Biomass
Hydro-gasification for production of dimethyl ether;
FIG. 21 is a diagram showing Thermal Energy Management Schematic of
Biomass Hydro-gasification for production of dimethyl ether;
FIG. 22 is a diagram showing Water/Steam Flow Schematic of Biomass
Hydro-gasification for production of dimethyl ether;
FIG. 23 is a diagram showing Molten Salt Flow Schematic of Biomass
Hydro-gasification for production of dimethyl ether;
FIG. 24 is a diagram showing Mass Flow Schematic of Biomass
Hydro-gasification for production of gaseous hydrogen fuel;
FIG. 25 is a diagram showing Mole Flow Schematic of Biomass
Hydro-gasification for production of gaseous hydrogen fuel;
FIG. 26 is a diagram showing Thermal Energy Management Schematic of
Biomass Hydro-gasification for production of gaseous hydrogen
fuel;
FIG. 27 is a diagram showing Water/Steam Flow Schematic of Biomass
Hydro-gasification for production of gaseous hydrogen fuel;
FIG. 28 is a diagram showing Molten Salt Flow Schematic of Biomass
Hydro-gasification for production of gaseous hydrogen fuel;
FIG. 29 is a diagram showing Mass Flow Schematic of Biomass
Hydro-gasification for production of electricity;
FIG. 30 is a diagram showing Mole Flow Schematic of Biomass
Hydro-gasification for production of electricity;
FIG. 31 is a diagram showing Thermal energy Management Schematic of
Biomass Hydro-gasification for production of electricity;
FIG. 32 is a diagram showing Water/Steam Flow Schematic of Biomass
Hydro-gasification for production of electricity;
FIG. 33 is a diagram showing Molten Salt Flow Schematic of Biomass
Hydro-gasification for production of electricity;
FIG. 34 is a mass flow schematic of biomass hydro-gasification for
Fischer-Tropsch paraffin fuel production using an adiabatic HGR and
a 9:1 water feed;
FIG. 35 is a molal flow schematic of biomass hydro-gasification for
Fischer-Tropsch paraffin fuel production using an adiabatic HGR and
a 9:1 water feed;
FIG. 36 is a thermal energy management schematic of biomass
hydro-gasification for Fischer-Tropsch paraffin fuel production
using an adiabatic HGR and a 9:1 water feed;
FIG. 37 is a water/steam flow schematic of biomass
hydro-gasification for Fischer-Tropsch paraffin fuel production
using an adiabatic HGR and a 9:1 water feed;
FIG. 38 is a molten salt flow schematic of biomass
hydro-gasification for Fischer-Tropsch paraffin fuel production
using an adiabatic HGR and a 9:1 water feed.
DETAILED DESCRIPTION OF THE INVENTION
A steam generator for pyrolysis, hydro-gasification reactor (HGR)
and steam pyrolytic reformer (SPR) (also called a steam pyrolytic
reactor, steam reformer or steam reactor) such as used in a Hynol
process, may be utilized to produce the synthesis gas (syngas)
through steam pyrolysis of the feed stock, hydro-gasification and
steam reforming reactions. The reactions start in the HGR to
convert carbon in the carbonaceous matter into a methane rich
producer gas and continue through the SPR to produce synthesis gas
with the correct hydrogen and carbon monoxide stiochiometry for
efficient operation of the Fischer-Tropsch process. With the
Fischer-Tropsch process as the final step in processing, products
such as synthetic gasoline, synthetic diesel fuel and recycled
water can be produced.
The feedstock requirement is highly flexible. Many feeds that
consist of different carbonaceous materials can be wet milled to
form a water slurry that can be fed at high pressure into a steam
pyrolyzer, hydro-gasifier and steam reformer reactors for synthesis
gas production. The feed to water mass ratio can even vary during
the running of the process, with a knowledge of the chemical
content of the feed, to maintain the carbon-hydrogen stiochiometry
required for an optimized fuel synthesis process. Appropriate
carbonaceous materials include biomass, natural gas, oil, petroleum
coke, coal, petrochemical and refinery by-products and wastes,
plastics, tires, sewage sludge and other organic wastes. For
example, wood is an example of waste biomass material that is
readily available in Riverside County, California. This particular
waste stream could be augmented with other carbonaceous materials,
such as green waste and biosolids from water treatment that are
available in Riverside County, and would otherwise go to
landfill.
When used to make a transportation fuel, such as diesel fuel, the
process is designed so that the feedstock makes the maximum amount
of Fischer-Tropsch paraffinic product required. The desired output
consists of a liquid hydrocarbon, such as cetane, C.sub.16H.sub.34,
within the carbon number range, 12 to 20, suitable as a diesel
fuel. Excess synthesis gas output from the SPR, i.e., "leftover"
chemical energy from the Fischer Tropsch synthetic fuel producing
process, can be used as an energetic fuel to run a gas turbine for
electricity production. The synthesis gas output after recycling
enough hydrogen to sustain the hydro-gasifier, may be used for this
purpose also, depending on the needs of the user. The following
provides a method for maximizing the economic potential from the
present invention in the conversion of carbonaceous materials to a
usable transportation fuels and inclusive of the possibility for
direct electric power production through a gas turbine combined
cycle.
1) Find approximate data on available carbonaceous wastes, their
chemical composition and perform further analysis on the practical
need for the process.
2) Model the important reactions within the process consisting of
the steam generator for pyrolysis, hydro-gasifier, steam reformer,
and the Fischer-Tropsch (or other fuel synthesis) reactor on a
continuous flow-through basis. This may be done by optimizing the
Fischer-Tropsch (or other fuel synthesizer) feedstock for the
optimum stoichiometric hydrogen to carbon monoxide mole ratio for
fuel to be synthesized.
3) Perform an economic analysis on the costs to obtain and prepare
the input material required, capital costs, operating and
maintenance, and product yield and costs.
Specific implementations are given below in conjunction with flow
charts provided in the Figures, demonstrating the conversion of
waste wood, as the candidate carbonaceous material, to a liquid
diesel transportation fuel, recycled water and an alternative power
source, via a Fischer-Tropsch process linked to a gas turbine
combined cycle.
The thermo-chemical conversion of carbonaceous materials occurs by
two main processes: hydro-gasification and steam reformation, with
steam pyrolysis of the feedstock occurring within the steam
generator to pre-treat feedstock and activate the carbon contained
therein. The hydro-gasifier requires an input of the pyrolyzed
carbonaceous waste, hydrogen, steam, reacting in a vessel at high
temperature and pressure, which in a specific implementation is
approximately 30 atmospheres and 1000 degrees Celsius. Steam
reforming of the methane rich effluent gas from the HGR also
requires an approximate pressure of 30 atmospheres and 1000 degrees
Celsius. More generally, each process can be conducted over a
temperature range of about 700 to 1200 degrees Celsius and a
pressure of about 20 to 50 atmospheres. Lower temperatures and
pressures can produce useful reaction rates with the use of
appropriate reaction catalysts.
Referring to FIG. 1, which is an overall flow diagram, the order of
general processes that carry out these main reaction processes is
shown (specific amounts for a particular embodiment are in the flow
diagrams shown in FIGS. 14 through 38). Piping is used to convey
the materials through the process. The feed 11 is chopped, milled
or ground in a grinder 10 into small particles, mixed with the
recycled water 12 and placed in a receptacle or tank 14 as a
liquid, suspension slurry 16 that is transportable as a compressed
fluid by a pump 18 to a steam generator 20 where the slurry 16 is
superheated and pyrolyzed, followed by either separation of the
steam in a steam separator 22 so that steam goes through piping 24
that is separate from piping that delivers the pumped, dense slurry
paste 26, or a direct steam pyrolysis feed through piping 27.
The dense slurry paste feed 26, or the direct steam pyrolysis feed
27, enters the HGR 28. Hydrogen from an internal source (from the
steam reformer via a hydrogen separation filter described below)
and a fraction of the previously produced steam flow into the HGR
28 for the desired output. The output gases consists largely of
methane, hydrogen, carbon monoxide, and super-heated steam. The
gases produced by the HGR 28 leaves the chamber and is pumped over
to the SPR 30. The un-reacted residue (or ash) from the HGR, is
periodically removed from the bottom of the reactor vessel using a
double buffered lock-hopper arrangement, that is commonly used in
comparable high pressure gasification systems. The ash is expected
to be comprised of sand, SiO.sub.2, and alumina, Al.sub.2O.sub.3,
with trace amounts of metals. The input to the SPR 30 is delivered
from either the steam separator 22 by piping 32 through a heater 34
and further piping 36, or via the HGR 28 output piping, to provide
greater-than-theoretical steam to carbon ratio into the SPR 30, to
mitigate coking in the reactor. The output is a higher amount of
hydrogen, and CO, with the appropriate stiochiometry for the
desired hydrocarbon fuel synthesis process described below.
The output of the SPR 30 is directed via piping 38 through heat
exchangers 40 and 42. Condensed water 44 is separated and removed
from the SPR output, via a heat exchanger and liquid water expander
47. The non-condensable gaseous output of SPR 30 is then conveyed
to a hydrogen separation filter 46. A portion of the hydrogen from
the SPR output, about one-half in this embodiment, is carried from
the filter 46, passed through the heat exchanger 40 with a
resultant rise in its temperature (in the embodiment from 220
degrees centigrade to 970 degrees Centigrade) and delivered to the
HGR 28 as its hydrogen input. The hot effluent from the SPR output
is cooled by passing through heat exchangers 40 and 42, used to
heat the recycled hydrogen, and make steam respectively. The
condensed water 44 leaving the heat exchanger 47 is recycled back
to make the water supply 12 for the slurry feed. By such means, a
self-sustaining process is obtained.
The fuel synthesis gas is then used for one of two options. Based
on the calorific value, the synthesis gas may go through a gas
turbine combined cycle for direct energy production or through a
fuel synthesis reactor (in this embodiment, a Fischer-Tropsch
process to produce a clean diesel fuel and recycled water). In
accordance with a specific embodiment of the invention, the
synthesis gas is directed through an expansion turbine 48, to
recover mechanical energy by lowering the pressure of the gaseous
feed into the Fischer-Tropsch reactor 50. The mechanical power
produced by the liquid state turbine, the Brayton and Rankine cycle
turbines can be used to provide power for internal slurry, water
feed pumps, air compressor, with the surplus exported via
electricity generation, see Tables 1 through 7.
Efficiency may be maximized by adjusting input and process
parameters. The biomass/coal varying-mixture feed is synthesized
into a slurry by adding water whereby after steam separation the
carbon to hydrogen ratio will be appropriate for the process. A
slurry feed needs enough water to run the hydro-gasifier, the steam
reformer, and to keep the feed in a viable slurry after steam
separation. Prior art attempts at biomass conversion using solid
dry feed had many mechanical problems of feeding a solid into the
high pressure, and high temperature HGR reaction chamber. This
method of slurry feed has already been demonstrated and studied,
according to the results for the "Hydrothermal Treatment of
Municipal Solid Waste to Form High Solids Slurries in a Pilot Scale
System", by C. B. Thorsness et al., UCRL-ID 119685, published by
Lawrence Livermore Nation Laboratory, Livermore, Calif. in 1995. In
addition, there is related art published on the making and
operating of coal water slurry feeds. For example, see Z. Aktas et
al., Fuel Processing Technology 62 2000 1-15. The principle
reactions of the two main processes, hydro-gasification and steam
reforming, are shown here. The HGR independent reactions can be
expressed as: C+2H.sub.2.fwdarw.CH.sub.4 (1)
C+2H.sub.2O.fwdarw.CO+H.sub.2 (2)
CO.sub.2+H.sub.2.fwdarw.CO+H.sub.2O (3)
Reactions 2 and 3 are endothermic, Reaction 1 is sufficiently
exothermic to provide the heat of reaction for reactions 2 and 3.
Some preheating of the HGR will be needed to bring the reactor up
to its operating temperature. Thus, the HGR is intended to be
self-sustaining once the reactions have started and achieve steady
state.
The main purpose of the HGR process is to maximize the carbon
conversion from the feed stock into the energetic gases CH.sub.4
and CO. After this process, hydrogen is produced by reacting
superheated steam with CH.sub.4 and CO within the SPR. In the SPR,
half the hydrogen is obtained from the superheated steam and the
remainder from the CH.sub.4. The principle reactions in the SPR are
considered to be: CH.sub.4+H.sub.2O.fwdarw.CO+3H.sub.2 (4)
CO.sub.2+H.sub.2.fwdarw.CO+H.sub.2O.fwdarw.CO.sub.2+H.sub.2 (5)
The steam reforming reactions (4 and 5) are often run with steam
concentrations higher than required for the stiochiometry shown
above. This is done to avoid coke formation and to improve
conversion efficiency. The required steam concentration is usually
specified in the form of the steam-to-carbon mole ratio (S:C), the
ratio of water steam molecules per carbon atom in the HGR feed. The
preferred (S:C) ratio for the SPR operation is greater than 3. This
steam rich condition favors the water-gas shift reaction. This
reaction is only slightly exothermic (.DELTA.H.degree.=-41 kJ/mole
CO); however, it produces additional hydrogen gas and converts
carbon monoxide into carbon dioxide. Unfortunately, an additional
unwanted secondary reaction can occur, the methanation reaction,
which consumes hydrogen: CO+3H.sub.2.fwdarw.CH.sub.4+H.sub.2O
(6)
The resulting effluent after the two main reactors is a synthesis
of gases rich in hydrogen, carbon monoxide, and steam.
Approximately half the hydrogen produced in the SPR is recycled
back to the HGR. Consequently, no outside source of hydrogen is
needed to maintain steady state operation. The HGR and SPR
processes, therefore, may be considered to be chemically
self-sustaining. The remaining synthesis gas is then available for
the production of fuels and process heat.
The present invention using the Fischer-Tropsch process can produce
a zero-sulfur, ultrahigh cetane value diesel-like fuel and valuable
paraffin wax products. The absence of sulfur enables low pollutant
and particle emitting diesel fuels to be realized.
The present invention also provides a source of by-products. One
useful by-product is purified water, which can be re-cycled to
create the slurry feed into the process. In a report by Rentech
titled "Fischer-Tropsch technology" dated 1998 see Rentech web
publications at http://www.rentechinc.com. Rentech states that the
Fischer-Tropsch process with an iron catalyst makes about 7/10ths
of a barrel of water per barrel of Fischer-Tropsch products. A
cobalt catalyzed Fischer-Tropsch process makes about 1.1 to 1.3
barrels of water for each barrel of Fischer-Tropsch products, a
greater amount than iron. Part of the water may be recycled to make
steam in the steam reformer unit and for cooling in both the
synthesis gas and Fischer-Tropsch step of the overall process.
The Fischer-Tropsch reactions also produce tail gas that contains
hydrogen, CO, CO.sub.2, and some light hydrocarbon gases. Hydrogen
can be stripped out of the tail gas and recycled either to the HGR
or the Fischer-Tropsch reactor. Any small amounts of other gases
such as CO and CO.sub.2 may be flared off.
Two main products of Fischer-Tropsch may be characterized as
synthetic oil and petroleum wax. According to Rentech, in the above
report for their particular implementation of the Fischer-Tropsch
process, the mix of solid wax to liquid ratio is about 50/50.
Fischer-Tropsch products are totally free of sulfur, nitrogen,
nickel, vanadium, asphaltenes, and aromatics that are typically
found in crude oil. The products are almost exclusively paraffins
and olefins with very few, or no, complex cyclic hydrocarbons or
oxygenates that would otherwise require further separation and/or
processing in order to be usable end-products. The absence of
sulfur, nitrogen, and aromatics substantially reduces harmful
emissions.
California's Air Resources Board (CARB) specifications for diesel
fuel require a minimum cetane value of 48 and reduced sulfur
content. The above Rentech study with Shell diesel flue produced
from a Fischer-Tropsch process has a cetane value of 76. The CARB
standard for sulfur in diesel fuel placed in the vehicle tank is
500 ppm by weight, and Shell's Fischer-Tropsch process diesel fuel
has no detectable amount in the ppm range. The CARB standard for
aromatic content is no more than 10% by volume (20% for small
refineries). The Shell Fischer-Tropsch process diesel fuel had no
detectable aromatics.
Rentech further affirmed through studies that the diesel fuel may
need no further processing because of the purity and olfin products
that may even be advantageous over crude oil diesel. The
Fischer-Tropsch diesel process is clean and the product is cleaner,
has a higher cetane value, and most likely does not need further
processing, when compared to a crude oil diesel.
A gas turbine combined cycle for electric power production is an
option. If the Fischer-Tropsch product is unexpectedly too costly,
the use of the synthesis gas heating value can be a viable option,
based on an overall efficiency of 65% of the synthesis gas energy
converting to electric energy. This number is reasonable since the
synthesis gas starts at a high temperature as opposed to taking
natural gas in from a pipeline.
Process modeling can be used to reasonably produce a synthesis gas
maximized for a yield high in CO and stoichiometric hydrogen.
First, the unit operation reactions of the hydro-gasifier, steam
reformer, and Fischer-Tropsch reactors are modeled. This may be
accomplished by using Stanjan, a DOS-based computer program that
uses equilibrium modeling. By varying the parameters of
temperature, pressure, original feedstock and gas flows, a
parameterization study was carried out based on costs and output
benefit. The hydro-gasifier variables were modified for the maximum
practical carbon conversion efficiency. The steam reformer
variables were modified for maximum practical CO output, enough
hydrogen for recycling output, and minimum CO.sub.2 production. The
study looked at the various parameters whereby two different values
varied for one constant, resulting in 3-D parameterization studies.
The following discusses the results from the computer modeling of
the main reactions using Stanjan programming.
Referring to FIG. 2, the effect of varying the water or steam and
hydrogen ratios on the conversion efficiency of carbon in feedstock
in the HGR is shown at 800.degree. C. and 30 atm. As the hydrogen
and water input to the HGR increases, the conversion efficiency of
carbon in feedstock increases until it reaches 100%. The condition
that falls in the area of 100% conversion efficiency achieves one
of the modeling objectives, and these conditions were used. In
order to avoid the cost of recycling of H.sub.2, the minimum amount
of H.sub.2 recycled to the HGR must be chosen. FIG. 3 shows the
effect of H.sub.2 and H.sub.2O on CH.sub.4 in the HGR at
800.degree. C. and 30 atm. FIG. 4 shows the effect of H.sub.2 and
H.sub.2O on CO.sub.2 in the HGR at 800.degree. C. and 30 atm. At a
high amount of H.sub.2 and low amount of H.sub.2O input, the amount
of CO.sub.2 is low. Although the objective is to minimize the
amount of CO.sub.2 in the synthesis gas, it is not necessary to
minimize CO.sub.2 in the HGR because CO.sub.2 is gauged in the SPR
reactions through the water-gas-shift reaction to obtain a proper
ratio of H.sub.2 and CO for a maximum Fischer-Tropsch diesel
fraction. FIG. 5 shows the effect of H.sub.2 and H.sub.2O on CO in
the HGR at 800.degree. C. and 30 atm.
FIGS. 6, 7, 8 and 9 show the effects of varying temperature and
pressure on the chemical composition of the effluent gases from the
HGR at feed of 2.76 mol H.sub.2 and 0.066 mol H.sub.2O per mole C
in the feed stock. At these conditions of H.sub.2 and H.sub.2O
input to the HGR, the carbon conversion efficiency is estimated to
close to 100% in a temperature range of 800 to 1000.degree. C. and
a pressure range of 30 atm. to 50 atm, for equilibrium
chemistry.
FIG. 10 shows the ratio of H.sub.2 and CO available for feed into
the Fischer-Tropsch fuel synthesis reactor, against the steam
content added to the SPR at 800.degree. C. and 30 atm. This ratio
increases with the increasing amount of steam added to the SPR and
reaches 2.1 at about 3.94 mol steam (or water) added per mol C in
feedstock. With this amount of steam added, the system will achieve
chemical and thermal self-substantiality and provide a proper ratio
of H.sub.2 and CO for Fischer-Tropsch synthesis of cetane. FIG. 11
shows the effect of H.sub.2O added to the SPR at 800.degree. C. and
30 atm. FIGS. 12 and 13 show the effect of temperature and pressure
on the H.sub.2 and CO ratio and the conversion of CH.sub.4 in the
SPR. At higher temperature and lower pressure, this ratio is
higher. In a similar trend with the H.sub.2 and CO ratio, the
conversion of CH.sub.4 increases with increasing temperature and
with decreasing pressure. It is thus high temperature and low
pressure favored in the SPR.
The products of Fischer-Tropsch paraffinic liquid fuels are in a
wide range of carbon number. According to the above Rentech report,
about half of the products are diesel fuel. Also about half of the
products come in the form of wax, with minor amounts of gases such
as un-reacted reactants and hydrocarbon gases (methane, ethane,
propane and so forth). To exemplify the present invention, cetane,
which is in middle position of diesel range (C.sub.11 to C.sub.20),
was chosen as diesel fuel.
The results of thermo-chemical and thermodynamic modeling of the
hydro-gasified conversion of waste wood (biomass), as a
prototypical carbonaceous feed material, were used to examine the
details and illustrate the features of this invention. These
simulations of the novel sequence of process reactors were
undertaken to discover the thermo-chemical conditions needed to
achieve the production of synthetic fuels. For example, in the
production of synthetic diesel fuel, the objectives were to attain
self-sustained operation of the first stage hydro-gasifier. In a
particular embodiment, this is accomplished at an equilibrium
temperature of 1000.degree. C. (738.degree. C. when adiabatic) and
30 atmospheres pressure with a total hydrogen to carbon feed mole
ratio of at least 3.48:1 (1.67:1 when adiabatic), and water to
carbon feed ratio of at least 0.07:1 (0.43 when adiabatic), a water
steam to carbon feed mole ratio of at least 3.91:1 (1.67:1 when
adiabatic) into the second stage steam reforming reactor also
operating at an equilibrium temperature of 1000.degree. C.
(900.degree. C. when adiabatic) and 30 atmospheres pressure, to
obtain conditions for simultaneous optimal quantities of product
hydrogen for self-sustained operation of the first stage
hydro-gasification reactor and an adequate hydrogen to carbon mole
ratio of at least 2.1:1 in the residual synthesis gas stream to
feed the third stage Fischer-Tropsch reactor, operating at
200.degree. C. and 10 atmospheres pressure, and adiabatic
self-sustained operation of a special HGR and SPR combination
reactor, followed by a conventionally operated SPR and
Fischer-Tropsch reactors, with full thermal and chemical potential
energy management.
Tables 1 through 5 show the overall energy transfer rates into and
out from each heat exchanger and power conversion component for
each operating mode of the conversion process. The mass flow, molal
flow, thermal energy management, water/steam and molten slat
schematic diagrams for each of the five operating modes of the
conversion process are also shown as FIGS. 14-18, 19-23, 24-28,
29-33 and 34-38 respectively. Tables 6 and 7 summarize the results
of the performance studies and process configuration parameters for
each of the five operating modes of the conversion process.
The carbonaceous material feed process initially described above
uses a water slurry suspension feed technology, originally
developed by Texaco for use in its partial-oxidation gasifiers,
that can accept a wide variety of carbonaceous materials, and can
be metered by controlled pumping into the first stage hydrogen
gasification reactor (HGR) to produce a methane rich gas with high
conversion efficiency (measured to have at least 85% carbon feed
chemical utilization efficiency). Enough heat is available to be
able to generate super-heated steam from the biomass-water slurry
feed to supply and operate the second stage steam-methane reformer.
The reformer product gas is fed into a hydrogen membrane filter
that allows almost pure hydrogen to pass back into the first stage
reactor to sustain the hydro-gasification of the biomass. The
remaining second stage product gas, not passing through the
hydrogen filter, is cooled to condense and re-cycle any water vapor
present back into the slurry carbonaceous feed system. The
unfiltered gas is fed into the fuel synthesis reactors, which
comprise a Fischer-Tropsch paraffin hydro-carbon synthesis reactor,
which operates at 200.degree. C. and 10 atmospheres pressure.
Process modeling reveals that the hydrogen/carbon molecular feed
ratio must be at least 2.1:1 to optimize production of chemically
pure and clean-burning [sulfur-free] diesel-like liquid fuels and
high value chemically pure paraffin-like waxes, without additional
fuel or energy. (FIGS. 14-18 and Tables 1, 6 and 7 or FIGS. 34-38
and Tables 5, 6 and 7 for adiabatic first sage reactor operation),
or a dimethyl ether synthesis reactor, which operates at
200.degree. C. and 70 atmospheres pressure. This reactor produces
approximately 92.4% DME and 7.1% methanol. The methanol is
combusted to co-generate about 30 MW of electricity and 20 MW of
process heat for exchange with the molten salt and water/steam heat
transfer loops (see FIGS. 19-23 and Tables 2, 6 and 7), hydrogen
gaseous fuel synthesis (see FIGS. 24-28 and Tables 3, 6 and 7), and
all electric power production without fuel synthesis (see FIGS.
29-33 and Table 4, 6 and 7).
Net export of electric power is possible in all five modes of
operation of the simulated biomass hydro-gasification process
plant. The results of these simulations are summarized in Table 6
and 7. The overall energy utilization does from 50.7% (71.2% when
adiabatic) for Fischer-Tropsch synthesis to 67.2% for hydrogen
production. Optimized electric power production utilizes about
38.2% of the chemical potential energy in the biomass feed stock
for clean-burning power conversion. In general the process modes
could be switched using an appropriate proportional valve to
distribute the synthesis gas production after separation of enough
pure hydrogen gas for the first stage hydro-gasification
reactor.
The results of the overall modeling shown in FIG. 1 are summarized
as follows.
1. Optimum conditions of the HGR: Operating at 1000.degree. C. and
30 atm; 2.76 mol H.sub.2 per mol C in feedback to maintain
self-sustainability; 0.066 mol H.sub.2O per mol C in feedstock.
2. Optimum conditions of the SPR: Operating at 1000.degree. C. and
30 atm; 4.022 mol H.sub.2O per mol C in feedstock.
3. Fischer-Tropsch products: 0.199 ton wax per ton of feedstock;
68.3 gallons of cetane (C.sub.16H.sub.34)diesel per ton of
feedstock.
Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims. Moreover, the scope of the present application is
not intended to be limited to the particular embodiments of the
process and apparatus described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure of the present invention, processes and apparatuses,
presently existing or later to be developed that perform
substantially the same function or achieve substantially the same
result as the corresponding embodiments described herein may be
utilized according to the present invention. Accordingly, the
appended claims are intended to include within their scope such
processes and apparatuses.
TABLE-US-00001 TABLE 1 Biomass conversion optimized for production
of Fischer-Tropsch Paraffins Energy rate in (MW) Energy rate out
(MW) Component PCE Heat Work PCE Heat Work Heat Exchangers HX 1
53.4 53.4 HX 2 Portion 1 78.8 Portion 2 212.9 HX 3 Portion 1 2.2
2.2 Portion 2 112.0 HX 4 (HGR) 50.2 HX 5 (SPR) 93.3 HX 6 Portion 1
46.6 Portion 2 8.7 HX 7 216.3 HX 8 43.3 Portion 1 of HX 2 78.8 HX 9
(FTR) 45.9 HX 10 11.8 HX G1 165.0 HX G2 21.8 HX G3 68.4 Hydraulic
Power Slurry Pump 0.3 Liquid State Water Turbine 0.2 Brayton Cycle
Turbine 1 7.9 Turbine 2 75.0 Turbine 3 0.0 Air Compressor 43.4
Rankine Cycle Heat 290.0 Mechanical Power 0.5 103.5 Waster Heat
From Steam Cycle 186.9 Chemical Conversion Process synthetic
paraffins produced 137 synthetic diesel fuel produced* 116 Input
into Conversion Process Biomass (waste wood) input PCE 473.0
Overall Energy Balances Total Energy 473.0 827.3 44.1 137 1014.2
186.6 Net Waste Heat Rejected 186.9 Net Input Energy Required 0.0
Power Conversion Process Net Electricity Production 123.8 Total
Electricity Available for Export 123.8 Overall Thermodynamic
Conversion Efficiency 50.7% notes *synthetic paraffins produced are
considered to be 50% cetane and 50% wax wax can be conventionally
processed to produce cetane with 70% efficiency
TABLE-US-00002 TABLE 2 Biomass conversion optimized for production
of dimethyl ether (DME) Energy rate Energy rate in (MW) out (MW)
Component PCE Heat Work PCE Heat Work Heat Exchangers HX 1 53.4
53.4 HX 2 Portion 1 54.5 Portion 2 160.0 HX 3 3.8 HX 4 (HGR) 50.2
HX 5 (SPR) 91.3 HX 6 36.6 HX 7 152.8 HX 8 29.9 Portion 1 of HX 2
54.5 HX 9 (DME-R) 32.3 HX 10 0.7 HX 11 1.6 HX 12 3.2 HX G1 150.2 HX
G2 21.3 HX G3 66.8 HX G4 Portion 1 (to HX 7) 49.4 Portion 2 (to HX
2) 64.5 Hydraulic Power Slurry Pump 0.2 Liquid State Water Turbine
Brayton Cycles Turbine 2 3.4 Turbine 3 4.0 Turbine 4 70.7
Compressor 5.2 Air Compressor 39.8 Rankine Cycle Heat (HX 3, 9, 10,
11, 12 & G4) 266.1 Mechanical Power 0.4 95.0 Waste Heat From
Steam Cycle 171.5 Chemical Conversion Process dimethyl ether (DME)
production 160.6 Input into Conversion Process Biomass (waste wood)
input PCE 473.0 Overall Energy Balances Total Energy 473.0 698.2
45.6 160.6 869.8 173.2 Net Waste Heat Rejected 171.5 Net Input
Energy Required 0.0 Power Conversion Process Net Electricity
Production 110.3 Electricity Available for Export 110.3 Overall
Thermodynamic Conversion Efficiency 57.3%
TABLE-US-00003 TABLE 3 Biomass conversion optimized for production
of gaseous hydrogen fuel Energy rate Energy rate in (MW) out (MW)
Component PCE Heat Work PCE Heat Work Heat Exchangers HX 1 53.4
53.4 HX 2 Portion 1 54.5 Portion 2 160.0 HX 3 105.4 HX 4 (HGR) 50.2
HX 5 (SPR) 91.3 HX 6 36.6 HX 7 152.8 HX 8 29.9 Portion 1 of HX 2
54.5 HX G1 151.0 HX G2 20.5 HX G3 Portion 1 (to HX 7) 10.7 Portion
2 (to HX 2) 53.6 Hydraulic Power Slurry Pump 0.2 Liquid State Water
Turbine Brayton Cycles Turbine 1 6.7 Turbine 2 57.3 Air Compressor
29.4 Rankine Cycle Heat 213.6 Mechanical Power 0.4 76.3 Waste Heat
From Steam Cycle 137.7 Chemical Conversion Process Gaseous H2 fuel
production 221.4 Input into Conversion Process Biomass (waste wood)
input PCE 473.0 Overall Energy Balances Total Energy 473.0 645.8
29.9 221.4 783.5 140.4 Net Waste Heat Rejected 137.7 Net Input
Energy Required 0.0 Power Conversion Process Net Electricity
Production 96.4 Total Electricity Available for Export 96.4 Overall
Thermodynamic Conversion Efficiency 67.2%
TABLE-US-00004 TABLE 4 Biomass conversion optimized for production
of electric power Energy rate in (MW) Energy rate out (MW)
Component PCE Heat Work PCE Heat Work Heat Exchangers HX 1 53.4 HX
2 Portion 1 78.8 Portion 2 212.9 HX 4 (HGR) 50.2 HX 5 (SPR) 93.3 HX
6 55.2 HX 7 216.3 HX 8 43.3 Portion 1 of HX 2 78.8 HX G1 243.2 HX
G2 Portion 1 73.0 Portion 2 (for Steam Turbine 2) 70.3 HX G3
Portion 1 (to HX 2) 77.1 Portion 2 (to HX 7) 88.0 HX G4 (from cold
side of HX G1) 56.4 56.4 Hydraulic Power Liquid Pump 0.3 Liquid
State Turbine 0.2 Rankine cycle #1 HX 2 (portion 2) 212.9 HX G3
77.1 Mechanical Power 0.5 103.5 Waste Heat From Steam Cycle 186.9
CPE of syntheisis gas fuel 596.8 Brayton Cycle #1 Turbine 1 7.9 Air
Compressor 64.6 Combined Cycles Gas Cycle Turbine 2 109.3 Steam
Cycle 2 HX G2 70.3 HX G4 56.4 Mechanical Power 0.2 45.3 Waste Heat
From Steam Cycle 81.7 Input into Conversion Process Biomass (waste
wood) input PCE 473.0 Overall Energy Balances Total Energy 473.0
1008.3 65.5 596.8 1276.9 266.2 Net Waste Heat Rejected 286.6 Net
Input Energy Required 0.0 Power Conversion Process Net Electricity
Production 180.6 Total Electricity Available for Export 180.6
Overall Thermodynamic Conversion Efficiency 38.2%
TABLE-US-00005 TABLE 5 Biomass conversion optimized for production
of Fischer-Tropsch Paraffins with increased input water:biomass
ratio = 9:1 and adiabatic HGR (AHGR) Energy rate in (MW) Energy
rate out (MW) Component PCE Heat Work PCE Heat Work Heat Exchangers
HX 1 22.8 22.8 HX 2 Portion 1 49.0 Portion 2 151.1 HX 3 Portion 1
56.4 Portion 2 24.8 HX 4 23.6 HX 5 (SPR) 129.8 HX 6 32.8 32.8 HX 7
603.4 481.8 HX 8 15.9 Portion 1 of HX 2 49.0 HX 9 (FTR) 37.4 37.3
HX 10 17.3 HX G1 122.0 HX G2 23.7 HX G3 Portion 1 18.8 18.8 Portion
2 8.0 Hydraulic Power Liquid Pump 0.6 Turbine 1 7.3 Turbine 2 54.9
Turbine 3 0.0 Brayton Cycle Turbine 4 20.5 20.5 Turbine 5 103.5
103.5 Turbine 6 1.0 1.0 Compressor 2.8 Air Compressor 31.2
Condenser Heat 85.8 Turbine 7 & 8 0.1 23.6 Waste Heat From
Steam Cycle 62.2 Chemical Conversion Process synthetic paraffins
produced 214.9 synthetic diesel fuel produced* Input into
Conversion Process Biomass (waste wood) input PCE 473.0 Overall
Energy Balances Total Energy 473.0 1106.9 34.7 214.9 1169.2 210.8
Net Waste Heat Rejected 62.2 Net Input Energy Required 0.0 Power
Conversion Process Net Electricity Production 155.1 Total
Electricity Available for Export Overall Thermodynamic Conversion
Efficiency notes *synthetic paraffins produced are considered to be
50% cetane and 50% wax wax can be conventionally processed to
produce centane with 70% efficiency
TABLE-US-00006 TABLE 6 Summary of Optimized Performance Studies for
Biomass Conversion Options* water/ useful feed rate biomass
production CPE rate percent Feed stock kg/hr MT/day ratio per day
MW ch CPE input Dry waste wood 83775 2011 473.0 100.0% Conversion
Options 1 Fischer-Tropsch Liquids (FTL) bbl/day bbl/ton water fed
used 264670 6352 3.2 MW h/ton synthetic diesel fuel 11526 277 2231
116.0 24.5% 1.11 electricity exported 123.8 26.2% 1.48 process
water recovered 295523 7093 excess water available 30853 740 Air
supply for combustion 456047 10945 CO2 produced 122356 2937
rejected waste heat 187.0 39.5% overall energy utilization 50.7% 2
Dimethyl ether (DME) bbl/day # bbl/ton water fed needed 184387 4425
2.2 MW h/ton dimethyl ether produced 20045 481 4530 160.6 33.9%
2.25 electricity exported 110.3 23.3% 1.32 process water recovered
207334 4976 excess water produced 22947 551 Air supply for
combustion 410739 9858 CO2 produced 119899 2878 rejected waste heat
171.5 36.3% overall energy utilization 57.3% 3 Gaseous Hydrogen
(GH2) cu m/day+ cu m/ton water fed needed 184387 4425 2.2 MW h/ton
gaseous hydrogen (GH2) 5618 135 1899 221.4 46.8% 0.94 electricity
exported 96.4 20.4% 1.15 water produced 180601 4334 excess water
produced -3785 -91 Air supply for combustion 429682 10312 CO2
produced 158173 3796 rejected waste heat 137.7 29.1% overall energy
utilization 67.2% 4 All electric Power (AEP) MW eh/day MW h/ton
water fed needed 260393 6249 3.1 electricity exported 4335 180.6
38.2% 2.16 water produced 311110 7467 excess water produced 50717
1217 Air supply for combustion 878774 16291 CO2 produced 158144
3795 rejected waste heat 230.0 48.8% overall energy utilization
38.2% 5 FTL with water:biomass at 9:1 and adiabatic HGR (AHGR)
bbl/day bbl/ton water fed used 753975 18095 9.0 MW h/ton synthetic
diesel fuel 18147 436 3512 182.7 38.6% 1.75 electricity exported
155.1 32.8% 1.85 process water recovered 775890 18621 excess water
available 21915 526 Air supply for combustion 456047 10945 CO2
produced 122356 2937 rejected waste heat 62.2 13.2% overall energy
utilization 71.4% revision Oct. 12, 2001 Notes No additional energy
or energetic feedstock is required for all conversion options All
rejected waste heat is at a temperature below 40 C. and is not
considered recoverable # DME stored as a compressed liquid at 20
C., 5.1 atm. pressure, density 668 g/L and LHV 28.4 MJ/kg
TABLE-US-00007 TABLE 7 Summary of Optimized Performance Parameters
for Biomass Conversion Options* water/ useful feed rate biomass
production CPE rate percent Feed stock kg/hr MT/day ratio per day
MW ch -- CPE input Dry waste wood 83775 2011 473.0 100.0%
Conversion Options 1 Fischer-Tropsch Liquids (FTL) bbl/day water
fed used 264670 6352 3.2 synthetic diesel fuel 11526 277 2231 116.0
24.5% electricity exported 123.8 26.2% process water recovered
295523 7093 Input conditions: T deg. C. P atm. H2/C H2O/C CO/H2
CH4/CO HGR 1000 30 3.48 0.07 SPR 1000 30 2.47 4.15 0.21 0.93
synthesis reactor 200 10 1.4 0.47 0.03 overall energy utilization
50.7% 2 Dimethyl ether (DME) bbl/day # water fed needed 184387 4425
2.2 dimethyl ether produced 20045 481 4530 160.6 33.9% electricity
exported 110.3 23.3% process water recovered 207334 4976 Input
conditions: T deg. C. P atm. H2/C H2O/C CO/H2 CH4/CO HGR 1000 30
3.48 0.07 SPR 1000 30 2.47 2.91 0.21 0.93 synthesis reactor 260 70
1.2 0.58 0.05 overall energy utilization 57.3% 3 Gaseous Hydrogen
(GH2) cu m/day+ water fed needed 184387 4425 2.2 gaseous hydrogen
(GH2) 5618 135 1899 221.4 46.8% electricity exported 96.4 20.4%
water produced 180601 4334 Input conditions: T deg. C. P atm. H2/C
H2O/C CO/H2 CH4/CO HGR 1000 30 3.48 0.07 SPR 1000 30 2.47 2.91 0.21
0.93 overall energy utilization 67.2% 4 All Electric Power (AEP) MW
eh/day water fed needed 260393 6249 3.1 electricity exported 4335
180.6 38.2% water produced 311110 7647 Input conditions: T deg. C.
P atm. H2/C H2O/C CO/H2 CH4/CO HGR 1000 30 3.48 0.07 SPR 1000 30
2.47 4.15 0.21 0.93 overall energy utilization 38.2% 5 FTL with
water:biomass at 9:1 and adiabatic HGR (AHGR) bbl/day water fed
used 753975 18095 9.0 synthetic diesel fuel 18147 436 3512 182.7
38.6% electricity exported 155.1 32.8% process water recovered
775890 18621 Input conditions: T deg. C. P atm. H2/C H2O/C CO/H2
CH4/CO adiabatic HGR 738 30 1.67 0.43 SPR 900 30 0.84 3.08 0.18
4.47 synthesis reactor 200 10 1.38 0.47 0.17 overall energy
utilization 71.4% revision Oct. 9, 2001 Notes No additional energy
or energetic feedstock is required for all conversion options All
rejected waste heat is at a temperature below 40 C. and is not
considered recoverable # DME stored as a compressed liquid at 20
C., 5.1 atm. pressure, density 668 g/L and LHV 28.4 MJ/kg 1 bbl of
compressed liquid DME has a mass of 106.2 kg and LHV CPE of 3.02 GJ
+ Cubic meters of liquified hydrogen (at 20 deg K.) per day 1 atm.
pressure Approximately 3.7 MJ/kg is needed to cool and liquify
hydrogen having an HHV of 144 MJ/kg *All thermochemical and
thermodynamic simulation data as of Oct. 1, 2001
* * * * *
References