ENERGY EFFICIENT SYSTEM AND PROCESS FOR THE CONTINUOUS PRODUCTION OF FUELS AND ENERGY FROM SYNGAS

A system and apparatus is provided that maximizes mass and energy conversion efficiencies in an integrated thermochemical process for the conversion of fossil fuel or renewable biomass to synthesis gas. The system combines gasification, catalytic conversion of gas to liquid, electricity generation, steam and chilled water generation with a system controller to maximize the conversion efficiency from syngas to merchantable products over the efficiency of syngas alone burned as a fuel. A clean synthesis gas stream is introduced into a catalytic reactor that utilizes specially formulated catalysts to generate liquid fuel from CO and H2 while concentrating CH4 and other combustible, but non-reactive gases in the syngas product stream. The methane rich stream is introduced into an engine for the production of electricity and heat while the unreacted CO and H2 can be recycled to produce additional liquid fuel. Excess heat can be used for other co-located processes and facilities.

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Description
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. provisional application Ser. No. 60/882,755 filed on Dec. 29, 2006, incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains generally to an improved energy efficient process for the continuous, co-production of liquid fuels, electricity and heat from syngas, and more particularly to a system and method which integrates thermochemical syngas production, catalytic conversion processes and electricity and heat production systems in a manner that maximizes the thermal energy efficiency for the conversion of carbonaceous materials to electricity and liquid fuels.

2. Description of Related Art

The worldwide demand for energy and transportation fuels is growing rapidly as fossil energy sources become more depleted, expensive, and environmentally problematic. A significant percentage of the production of electricity in the United States comes from conventional pulverized-fuel-fired boilers linked to a conventional steam cycle. Such generation systems have modest efficiencies and contribute to the global emissions of nitrogen oxides, sulfur oxide, carbon dioxide, and particulate matter. Furthermore, in some coal combustion plants, only a third of the energy value of the coal is actually converted into electricity and the rest is lost as waste heat.

Improved and innovative systems are needed that will provide alternative energy sources and options to meet future energy needs and address rising pollution issues. Even though there are many technologies that are capable of changing energy fuels from one form to another, existing energy conversion systems have limited efficiencies and notable waste.

This has also driven the development of new energy technologies that are capable of converting non-petroleum and non-fossil fuel resources into useable fuels and electricity. Part of this challenge is to develop low cost and scalable systems that can achieve high energy conversion efficiencies.

It has long been known that carbonaceous materials such as agricultural, forest and municipal waste (“biomass”) as well as natural gas, coal, oil shale and oil sands (“fossil resources”) can be converted into combustible gases by thermochemical processing. These thermochemical processes utilize conversion technologies such as gasification, reforming, pyrolysis, catalysis and other relevant processes for the conversion of fossil fuels (natural gas, coal, oil, oil shale, etc) and renewable biomass to synthesis gas (syngas). For example, the energy options available to the world could be significantly expanded with the economical conversion of biomass and fossil resources to synthesis gas with further conversion to liquid fuels. Rather than burning biomass or fossil resources directly, gasification, a thermo-chemical process is used to produce a mixture of carbon monoxide, hydrogen and methane, known as syngas. The resulting syngas is more versatile than the original solid biomass or fossil resources and has energy conversion possibilities that have advantages over other outputs created by direct burning.

Since the early 1900's, a number of thermochemical processes have been developed for the conversion of carbonaceous materials derived from renewable and fossil resources. These thermochemical processes convert carbon containing compounds into syngas, a mixture comprised primarily of CO and H2, which can also contain amounts of CO2 and CH4 with traces of other hydrocarbons. The technology for the production of biomass and fossil resources continues to be developed and advancements in production efficiency have been seen. Improved conversion technologies can provide benefits ranging from reduced environmental impacts to higher energy efficiency as well as secure and reliable electrical power production and fuel availability.

Also discovered in the early 1900's was the process for hydrogenation of CO over transition metal catalysts to produce liquid hydrocarbons and oxygenated compounds. Numerous catalyst formulations have been developed to produce liquid fuels and chemicals from syngas feedstock. For example, Fe, Co and Ni based catalysts have been used extensively for the synthesis of mixtures of paraffins and olefins that can be converted to gasoline and diesel fuels. Copper based catalysts have been used for methanol and mixed alcohol production. Other metals have been proposed for deriving other specific products, for example Rh based catalysts developed for acetic acid, acetaldehyde and ethanol production. Also mixtures of catalyst metals (e.g. Rhodium and Copper) have been shown to give higher selectivity for the production of ethanol. These catalysts typically operate at elevated pressures (500-2000 psig) and temperatures (400-650° F.). The conversion efficiencies of the primary reactants (CO and H2) to fuels can be low for alcohol synthesis (15-30%) and higher for the synthesis of chain hydrocarbons (40-80%). The amount of gas conversion decreases with gas hourly space velocity but yield and selectivity for certain products can be improved with higher space velocity. For these synthesis catalysts, optimum space velocities are on the order of 1000 to 10,000 hr−1 using normalized gas volumes.

The chemistry involved in synthesis can include the following generalized reactions.


CO+3H2→CH4+H2O  (Methanation)


nCO+(2n+1)H2→CnH2n+2+nH2O  (Alkanes/Paraffins)


nCO+2nH2→CnH2n+nH2O  (Alkenes/Olefins)


nCO+2nH2→CnH2n+1OH+(n−1)H2O  (Alkanols/Alcohols)


CO+H2O→H2+CO2  (Water-Gas Shift)

In the synthesis of hydrocarbon and alcohol compounds with two carbons or greater, 100% selectivity for the desired compounds is not currently achievable. In addition to a mixture of liquid products, some gaseous side products are generated including carbon dioxide from the water-gas shift reaction and methane from the above methanation reaction. As described in previous systems, methane can be recycled by being reformed back to CO and H2. Steam reforming has been described for the production of additional CO and H2. The CO and H2 are then added to the syngas at a point before the catalytic reactor. Since these reformers require elevated pressures and temperatures, additional external energy is needed, resulting in lower thermal energy efficiency for the production processes.

Accordingly, there is a need to identify and develop advanced technologies that will improve the efficiency or reduce the cost of producing electricity, liquid fuel, fuel gases, chemicals and heat recovery utilities like steam within an integrated system. There is also a need for a system with the capability of producing electricity, fuel gases, steam, liquid fuels and chemicals, or various combinations of these materials, while greatly reducing air pollutants and greenhouse gas emissions. The present invention meets these needs as well as others and is a substantial improvement over the art.

BRIEF SUMMARY OF THE INVENTION

The present invention is an integrated system with processes configured to generate liquid fuels, electricity and heat from carbonaceous fuel sources. The preferred system combines and maximizes the carbon and energy conversion potential and efficiency of the associated components or subsystems to produce a system for the co-production of fuels and electricity from syngas. The process can produce liquid fuels and electricity from carbonaceous feedstock at net thermal energy efficiencies of greater than 40-50%, which are significantly higher than fuel synthesis or electricity generation alone.

Some of the other advantages of the present invention over the prior art include simplified process steps through the real-time monitoring of gas composition before and after the catalyst reactor, monitoring of process conditions (such as temperature, pressure and gas flow velocity) optimization of hydrogen/carbon monoxide gas composition using a hydrogen generator, the use of neural network algorithms and kinetic/thermodynamic models with feed-back control, for process optimization, and the use of chemical species (e.g. methane) that are relatively catalytically non-reactive to generate electricity and heat. This simplified system optimizes fuel, electricity and heat production, resulting in high net energy efficiencies and system flexibility.

The main subsystems include: syngas generation, a catalytic reactor for the production of liquid fuels from syngas, a hydrogen generator, on-line analytical instruments for monitoring gas phase species before and after the catalyst, on-line sensors for monitoring temperature, pressure and gas flow, a process control system that collects on-line data and controls catalyst process conditions, a gas/liquid separator, a gas-recycle system and equipment for the production of electricity and heat from the gas-phase components that were not used for conversion to fuels. These subsystems can be adapted to produce different types of liquid fuels, electricity and heat that can be sold as commercial products.

In one embodiment of the invention, syngas and hydrogen generators are provided. In another embodiment, the syngas and hydrogen are provided from a source outside of the system. Carbon monoxide may also be supplemented in one embodiment. The system is ideally suited for small and medium sized, distributed conversion facilities that are located near feedstock resources for the production of syngas but may also be used in larger designs that may function as regional fuel and electricity production centers. Syngas, comprised primarily of CO, H2, CO2 and CH4, is derived from any carbonaceous feedstock material such as agricultural, forest and municipal waste as well as natural gas, coal, oil shale and oil sands by utilizing conversion technologies such as gasification, reforming, pyrolysis, catalysis and other relevant processes.

The syngas is pressurized and fed to a synthesis reactor to be converted to desired liquid products. Catalyst formulations are selected to convert CO and H2 to products such as alcohols and liquid hydrocarbons. The liquid products are cooled and separated from the un-reacted gases. Catalyst formulations are also selected to convert CO and H2 in the syngas to the desired fuel products such as alcohol and liquid hydrocarbon fuels without significantly altering the more energy rich chemical species such as methane and other catalytically, non-reactive species in the syngas.

A portion of these un-reacted gases can be recycled to the synthesis reactor while the remainder is used to generate electricity and steam. The process of catalysis and recycling concentrates species of combustible but catalytically non-reactive species (like CH4) in the product gas.

The desired liquid products are separated from the energy enriched gas stream and an on-line process analyzer is used to monitor the concentrations of the primary gas species. This information, along with process control algorithms, is used to adjust the amount of gas that is recycled through the catalyst versus the amount of gas that is sent to the engine/generator or gas-turbine. This integrated, continuous process results in an optimized production of liquid fuels, electricity and heat.

A portion of the product gas and the electricity generated by the system may be used to provide process energy for various parts of the system including the syngas generator, a hydrogen generator and other equipment described in detail below. An analog and/or digital control system optimizes the gas composition for production of fuels and electricity.

Some of the electricity and heat may be used to produce hydrogen, which may be added to the incoming syngas to increase the yield of liquid fuel products. The composition of the syngas stream may be further supplemented by passing carbon dioxide gas over heated charcoal to form carbon monoxide increasing the concentration of this gas to the reactor. Hydrogen gas may also be added to bring the concentrations of CO and H2 to the desired ratio.

The electricity and heat generated in this system may also be used to run the process and it may also be used as a clean energy source for the syngas production systems. Excess electricity may be distributed to the regional electrical grid. The excess heat can be used for other co-located processes and facilities.

According to one aspect of the invention, a system for the production of liquid fuels and electricity from syngas is provided that 1) generates synthesis gas (syngas) from a carbonaceous feedstock (e.g. agricultural, forest and municipal waste, natural gas, coal, oil shale and oil sands) using a thermochemical process, catalytic reformer and/or other relevant technology or combination thereof; 2) introduces a clean syngas stream (primarily CO, H2, CH4, CO2 and H2O at varying concentrations) to a catalytic synthesis reaction system to simultaneously generate liquid fuel from CO and H2 while concentrating CH4 and other combustible but non-reactive gases in a gas product stream; and 3) introduces the CH4 rich product gas stream into an engine, gas-turbine or other relevant technologies for the production of electricity and heat.

According to another aspect of the invention a system is provided where catalyst formulations in the synthesis reactor are selected to operate under conditions in which CO reacts efficiently with H2 to produce alcohol, diesel, gasoline, ether or hydrogen fuels as well as create conditions in which CH4 and other light hydrocarbons are relatively non-reactive over the catalysts.

Process optimization is optionally facilitated by the injection of additional hydrogen into the catalyst reactor produced by electrolysis or other source to improve liquid fuel production efficiency. The process control computer is used to change the proportion of liquid fuel production to electricity/heat production and dictated by real-time electricity and liquid-fuel market fluctuations and requirements.

According to another aspect of the invention, a system is provided that monitors the composition of the pre- and post-catalyst gas stream and uses that information with an on-line process controller to optimize the recycle ratio of the post-catalyst gas stream and other process controls with the purpose of generating a CO and H2 rich gas stream suitable for fuel synthesis via catalysis, as well as a CH4 and other light combustible rich gas stream that is ideal for the production of electricity and heat.

Another aspect of the invention provides a controller wherein chemical thermodynamic and energy models and/or advanced learning algorithms (e.g. neural networks) are used in an on-line digital and/or analog process control system to help determine the desired process conditions and split ratios of the gas stream to the catalysts and the engine/generators and/or gas turbine/generators.

According to another aspect of the invention the energy efficiency of the process is maximized by monitoring the pre- and post catalyst gas stream composition and using that information in an on-line process control system to vary fuel production vs. electricity and heat production. The on-line process control system preferably employs kinetic/thermodynamic models and neural network systems.

According to a further aspect of the invention, sensors monitor the gas composition at one or more locations, in combination with chemical thermodynamic and energy models to control the addition of the hydrogen into the pre-catalyst syngas stream to enhance the catalyst conversion efficiencies of CO, CO2 and other catalytically reactive species to fuels.

Yet another aspect of the invention provides a process control system to change the proportion of fuel production to electricity and heat production, depending upon real-time market conditions. For example, when there is a peak load demand for electricity, the amount of electricity can be increased to help meet that demand.

Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only:

FIG. 1 is a system flow diagram of a process according to the present invention.

FIG. 2 is a system flow diagram of an integrated system of syngas production, liquid product production and steam and electrical production according to the invention.

 DETAILED DESCRIPTION OF THE INVENTION

The present invention is an integrated, continuous process that maximizes the carbon and energy conversion efficiencies for the simultaneous production of liquid fuels, electricity, and heat from syngas. The process is optimized using an on-line computer system with the use of continuous gas analyzers and process algorithms to control and to maximize product yields and energy efficiency. This process invention significantly reduces the complexity of current, commercial systems for the synthesis of liquid products, resulting in significantly lower capital and production costs.

As seen schematically in FIG. 1 and FIG. 2, the system for producing liquid materials and combustible gas for the generation of electricity and heat has several subsystems of processes. The primary processes are syngas generation, hydrogen generation, synthesis, liquid separation, gas recycling, electricity generation, heat recovery and system control.

The syngas production and liquid material production subsystems 12 of the production system 10 of FIG. 2 are shown in FIG. 1. The liquid production subsystem 12 can produce different liquid materials from a source of syngas depending on the selection of the reactor catalysts and reaction conditions.

Synthesis gas is defined as a gas comprising primarily carbon monoxide (CO) and Hydrogen (H2) from any source. Typical synthesis gas includes carbon monoxide, hydrogen and lesser amounts of carbon dioxide (CO2) and other useful gases such as methane (CH4) as well as small amounts of light paraffins, such as ethane and propane. It may also contain gases such as nitrogen, argon, oxygen-containing compounds and water in a gaseous state. However, the preferred ratio of hydrogen to carbon monoxide is 0.5 to 5, and 0.75 to 2.5 by molar ratio is particularly preferred. Accordingly, the proportion of carbon monoxide and hydrogen together in the reactant gas is preferably about 20% to about 100% by volume.

The syngas production subsystem 14 preferably has a syngas generator 16 that processes fuel 18 to produce a stream 20 of synthesis gas. Although a syngas production subsystem 14 is provided in the embodiment of FIG. 1 and FIG. 2, it will be understood that syngas may be transported by pipeline from a storage source or production source outside of the system.

Syngas can be generated from a wide variety of carbonaceous fuel sources 18 including petroleum waste products, coal, wood, straw, waste tires, natural gas, landfill gas, or any other carbon containing matter. Many technologies have been developed to thermally convert a carbonaceous feedstock to syngas. The specific method for producing syngas and type of syngas generator are not essential to the system 10. However, the type of syngas generator 16 that is selected is preferably one that has low energy requirements. Because one of the objectives of the apparatus and system is to synthesize liquid fuels from CO and H2, technologies that maximize the production of these gases are preferred. Examples of preferred technologies for this invention include pyrolyzers, gasifiers, steam or hydro-gasification systems, steam reformers, autothermal reformers or combinations of these technologies.

Currently, there are three types of gasifiers: fluidized bed types, fixed bed types and entrained flow types. In the typical gasification process, the fuel 18 is heated to a very high temperature in the range of 1000° C. to 1500° C., while under pressure (20 bars to 85 bars). Controlled amounts of steam and oxygen are introduced to produce two sets of reactions. The first reaction is a partial oxidation of the fuel 18 that produces additional heat required for the second set of reactions (pyrolysis) which are endothermic. As a result, virtually all of the organic material is gasified into primarily carbon monoxide and hydrogen and the inorganic material is converted to slag.

The technology used for syngas generation preferably meets other criteria. The ratio of H2 to CO can be important for synthesis and a ratio of 0.5 to 5.0 is preferred, a ratio of 0.75 to 2.5 is optimally preferred.

The amount of CO2 in the syngas can also impact the synthesis activity, depending on the type of catalyst utilized. Accordingly, a preferred maximum CO2 concentration in the syngas ranging from 0-25% is preferred, 0-10% is optimally preferred. Therefore, a system to remove some of the CO2 from the syngas stream may be included in the syngas generation system 14 in one embodiment. In another embodiment, waste heat is used to heat charcoal or other carbon source and carbon dioxide gas is passed over the heated charcoal to produce carbon monoxide, thereby increasing the concentration of carbon monoxide and decreasing the concentration of carbon dioxide within the syngas stream.

Catalyst contaminants like sulfur and chlorine containing gases, tars, and particulates may also require removal. Gas cleaning technologies like scrubbers, traps, precipitators, etc. may be included in the syngas generation system in certain embodiments.

Since syngas generation is generally an endothermic process that requires heat to produce the reaction temperatures, heat from the fuel feedstock 18, the generated syngas or from another external source is required to maintain a continuous reaction. The source of the heat required for the syngas generator 16 can come from any source. In one embodiment, the reactor heat is supplied from the product gas that remains after the liquid synthesis reactions to maximize the efficiency of the fuel synthesis. In other embodiments, this heat can be supplied from the feedstock (auto-thermal), generated syngas (before synthesis), or an external fuel source. The thermal efficiency of the syngas generation system should be high to maximize system efficiency and reduce parasitic load on the overall system. Thermal efficiencies of greater than 50% are preferred and greater than 70% is optimally preferred.

In addition, the gases leaving the syngas generator are normally in excess of 1000° C. and need to be cooled down before they are introduced to the catalytic reactors 28. Generated electricity may be needed for certain parts of the syngas generation system including pumps, feedstock handling equipment, condensers, precipitators, etc.

In one embodiment, the excess thermal energy is converted to electrical energy for use in other parts of the system or for sale on the power grid. For example, steam can be generated through a heat exchanger in the syngas outflow by either convection or conduction. The resulting steam can be used to drive a turbine or other electrical generation device as well as used in other parts of the system or sold for other industrial uses of steam.

In order to maintain the proper balance of CO to H2 in the syngas for the desired synthesis reactions, the introduction of hydrogen to the syngas may be beneficial. An on-line continuous gas analyzer 22 optionally monitors the concentrations of carbon monoxide and hydrogen as well as other gases so that the composition of the feed gas 20 can be manipulated to keep the proper ratio of CO to H2 approximately constant by introducing additional hydrogen gas into the gas stream. A stream of syngas with a generally consistent composition can improve the conversion efficiency in the reactors 28. Hydrogen generator 24 or other source of hydrogen gas provides hydrogen gas to the stream of syngas 20 as determined by the gas analyzer 22. The composition of the gas can be sampled at different locations of the system and analyzed by gas analyzer 22. For example, the composition of gas entering 30 and exiting 36 the catalyst reactors 28 as well as the recycle gas 32 so that the gas composition can be optimized and the production of liquid products can be maximized.

In the preferred embodiment of the invention, hydrogen can be generated from electrolysis of H2O and fed into the feed syngas 30. High temperature electrolysis for the production of hydrogen gas and oxygen gas takes advantage of the waste heat of the syngas generator or other heat sources in the system. In another embodiment, hydrogen rich gas can also be generated from natural gas by steam reforming or from other emerging methods of production. Carbon monoxide concentrations of the feed gas may optionally be supplemented through carbon dioxide conversion or from an outside source.

The system is controlled to provide the optimal ratio of H2 to CO in the overall gas seen by the catalyst (including feed syngas and recycle gas). A ratio of 0.5 to 5.0 is preferred; a ratio of 0.75 to 2.5 is optimally preferred. This ratio may be catalyst dependent.

The syngas stream 20 is compressed by a compressor 26 to approximately the desired reaction pressure that is in the catalyst reactors 28. The combined feed syngas should be pressurized before it enters the synthesis reactors 28. The reaction pressure impacts the productivity and selectivity of the synthesis reactions in the reactors. Selection of the reaction pressure is dependent on the type of catalyst, but generally pressures in the range of 50-2000 pounds per square inch (psi) may be required, and pressures of 50-1000 psi are optimally preferred. A suitable gas compressor 26 may include a reciprocating compressor, centrifugal compressor, diaphragm compressor, or other suitable device to achieve the required reaction pressure. In the preferred embodiment, the compressor 26 can be run with an electric motor and electricity from the system. In another embodiment, the compressor is powered by an engine operating on product gas or steam generated from heat from the synthesis reactor 16.

The syngas feed 30 from compressor 26 may be combined with recycled gas 32 that has been compressed to the approximate pressure of the syngas feed 30 by compressor 34. In the embodiment shown in FIG. 1, the combined gas feed enters the temperature controlled reactor vessels 28. However, the recycled gases 32 could also enter the reaction vessel 28 separately. Although recycling of gas is shown in the apparatus of FIG. 1 for efficiency, it will be seen that some of the desired liquid products can be produced with a single pass through the reactor 28.

The pressurized feed syngas and recycle gas streams 30 are fed into at least one synthesis reactor 28 or a series of reactors as shown in FIG. 1 and FIG. 2. Catalyst reactors 28 may be in parallel or in series. In one embodiment, reactors containing different catalyst compositions are connected in series to provide sequential reactions.

In the preferred embodiment, the reactor 28 is a shell and tube type synthesis reactor or a fixed bed reactor. In a shell and tube reactor, the gas flows through tubes that contain the catalyst that are surrounded by boiling water, all contained within the vessel shell. The temperature is controlled by controlling the pressure of the boiling water and steam is produced that can be used for energy production or other processes. Another preferred embodiment includes a fixed bed reactor where coolant flows through tubes in a catalyst bed to remove reaction heat. Syngas flows across the bed and products are removed from the opposite end of the bed. Other preferred embodiments include a fluidized bed reactor or a slurry-type fixed bed reactor. The design of the reactor is dependent on the syngas throughput, space velocity, temperature and pressure of the system.

Each synthesis reactor 28 contains a catalyst or multiple layered catalysts chosen to synthesize the desired liquid product from the syngas fed into the reactor. To synthesize methanol, for example, Cu—Zn based catalysts on alumina supports are optimally preferred. To synthesize higher alcohols, particularly ethanol, a supported Cu—Zn catalyst layered with a Group VIII metal catalyst is optimally preferred. To synthesize hydrocarbon liquids for diesel fuel production, a supported Fe based catalyst promoted with Cu and K is optimally preferred. In other preferred embodiments, any other catalyst including un-supported, supported, and slurry-phase catalysts that have high selectivity and productivity for any desired liquid product can be used. Many other synthesizable compounds and catalyst formulations for generating those compounds are known to those skilled in the art.

One catalyst configuration in reactor 28 has three stages and selectively produces ethanol at high yields from synthesis gas and is illustrated in Example 2 below. In this embodiment, syngas is directed over a first catalyst configured to promote carbon monoxide hydrogenation. The hydrogenated gas from the first catalyst then reacts with a second catalyst configured to promote alcohol homologation. Thereafter, the gas from the second catalyst reacts with a third catalyst that is configured to promote hydrogenation of acid and aldehyde byproducts to alcohols. The reactions preferably occur under conditions of super-atmospheric temperature and pressure.

In one illustrative embodiment, the reactor 28 is packed successively with three layers of catalysts:

    • (1) A hydrogenation catalyst containing Cu—Zn, Mo, Ni, or Fe;
    • (2) A carbonylation catalyst containing:
      • (a) A Group VIII metal or mixture of Group VIII metals;
      • (b) A co-catalyst metal of yttrium, a lanthanide and/or actinide series metal or mixtures thereof; and
    • (3) A second hydrogenation catalyst composed of Cu—Zn, Mo, Ni, or Fe.

The synthesis reactions in reactor 28 primarily convert the CO and H2 to desired products depending on the selection of the catalysts. The amount of gas converted is dependent on the activity of the catalyst and the space velocity of the gas along with other operational criteria. In the preferred embodiment, a CO conversion rate of greater than 15% is desired but rates greater than 50% are optimally preferred. The optimally preferred conversion rate is not achievable with certain catalysts.

Synthesis may include the generation of gas species that are not catalytically reactive including CO2 and CH4 and other gaseous hydrocarbons. These gases may help increase the energy content of the product gas stream which is useful for electricity generation. They should not greatly impact synthesis when they are recycled to the reactor 28.

The temperature, pressure and flow of the syngas stream 30 through the reactors 28 is preferably controlled and monitored to optimize the reaction conditions within the reactors 28. For example, the reactor vessel 28 may include heating or cooling elements that permit the regulation of the temperature of the gas flowing through the reactor vessel 28 within the desired range of temperatures that will optimize the reactions. The reaction vessel 28 may also have temperature and pressure monitors to allow the regulation of the temperature and pressure of the gas stream through the reaction vessel 28. In one embodiment, the temperature and pressure in each of the three stages can be varied.

For the production of ethanol, for example, the reaction temperature within reactor 28 preferably ranges from approximately 150° C. to approximately 400° C., with approximately 180° C. to approximately 325° C. particularly preferred. When a high reaction temperature is used, the formation of hydrocarbons as byproducts increases.

For some reactions the reactor pressure can be low, namely approximately 200 pounds per square inch gauge (psig), because desired compounds can be manufactured at that pressure. However, higher pressures can be utilized in order to increase the space/time yield. Therefore, the preferred reaction pressure can vary between approximately 200 psig and approximately 2500 psig. A reaction pressure ranging from approximately 500 psig to approximately 1500 psig is particularly preferred.

The feed rate of the reactant material gas relative to the volume of catalyst (also known as the gas hourly space velocity, GHSV, expressed under normal conditions of 0° C. and 0 psig) is preferably between 100 and 40,000 hr−1 (reciprocal hours) and is preferably adjusted for each catalyst component and the reaction conditions to optimize production of the desired liquid material. Increasing the space velocity can increase yield and selectivity of the desired products but reduces the carbon conversion, requiring more recycling of the gas.

It can be seen that the reaction conditions can be regulated to maximize the reaction efficiencies of the catalysts and products that are selected. Additionally, gas treatments devices such as scrubbers may be used to remove unwanted components of the syngas or recycled gas such as carbon dioxide or hydrogen sulfide. These treatment devices can be placed in the gas lines in parallel with the reactors or in series upstream or down stream from the reactors 28.

After passing though the catalysts in reactors 28, the outlet stream of gaseous products 36 is directed to the gas/liquid separator 38. The gas-liquid separator 38 is preferably a condenser but may be any other gas-liquid separator known in the art. The separated liquid products 40 are collected and stored for further processing.

In one embodiment, the separation system is a condenser using chilled coolant supplied from the waste heat from the system. Liquid product is removed from the bottom of the condenser. In another embodiment, the separator 38 may include some distillation and fractionating equipment to separate species based on boiling point.

Once liquid compounds 40 are separated, the product and un-reacted gases are split into two gas streams, the recycle gas 32 and purge gas 42. The recycle gas 32 is mixed with feed syngas 30 from a syngas generator 16 and then recycled through the catalyst, resulting in additional CO and H2 conversion to liquid product 40. The remaining gases 36 emerging from the gas/liquid separator 38 are preferably recycled for several cycles by compressing the gas stream with compressor 34 as needed to approximately match the pressure of the syngas feed stream 30 entering the reactors 28. Valve 44 can be used to direct gas that has been cycled through the reactors 28 several times to an exit line feed of purge gas 42. It will be seen that the cycling of gases through the reactor effectively concentrates some of the useful gases such as methane that are produced by the process or are present in the syngas feed 30. Gas products 42 can be burned as a source of heat, electrical generation, or can be processed further as an additional feedstock for other chemical production. The gas recycle rate can be varied from 0 to 99%. Lower recycle rates favor more electricity production while higher rates favor liquid product production. The recycle gas 32 is preferably maintained at elevated pressure but may require some additional compression to compensate from pressure drop through the reactor/separator system with compressor 34.

Turning now to FIG. 2, the syngas production subsystem 14 and the liquid material production subsystem 12 are integrated with an electrical generation subsystem 50 and controller subsystem 52 in the embodiment shown. The control subsystem 52 is connected to each of the subsystems to monitor and control the overall system 10. The production of gas, liquid material, electricity and steam can be optimized and controlled.

In the embodiment shown schematically in FIG. 2, the purge gas 42, consisting primarily of CH4 and other combustible product gases and CO2 at high recycle rates, is used to produce process energy and electricity generation. The stream of purge gas 42 can be divided and a portion 46 of the gas can be used to supply process energy for the syngas generator as described earlier. The second portion 48 and majority of the gas is delivered to an engine/generator 54 in the preferred embodiment. Methane rich purge gas 42 may alternatively be a source of hydrogen and carbon monoxide with further processing (not shown).

It can be seen that electricity can be produced by the electrical generation subsystem 50 in two ways. First, electricity can be produced by burning gas directly as fuel in a turbine or engine 54 that turns generators 56 to produce electricity as in a conventional natural gas fired generator. The second source of electrical production comes from steam 58 produced from the hot exhaust gases from the turbine or engine 54, which can be used to turn a steam turbine generator. Electricity can be produced by the whole system in a third way from steam produced by the syngas generator, described previously, that can drive a steam turbine to generate electricity for the system or for distribution to the municipal power grid. The multiple sources of electrical power generation are more efficient for converting the energy from biomass or coal to electricity than direct burning as fuel.

Alternatively, steam 58 produced by the engine 54 and the syngas generator 16 can be combined to run one or more turbines for electrical generation and the excess system steam sold to co-located facilities.

In the embodiment shown in FIG. 2, waste heat from the engine 54 is used to produce both steam 58 and chilled water 60 (via an ammonia absorption chiller). Chilled water 60 and steam 58 generated from the heat sources can be used for the process heat and chilling requirements for the system and are merchantable to a local cogeneration host.

An automatic process controller subsystem 52 with controller computer 62 and multiple system and subsystem sensors monitor the gas composition to control and optimize the production processes from syngas generation to synthesis and electricity generation. For example, continuous gas composition and flow analyzers 22, 64 monitor the gas at multiple points in the system, preferably after the syngas generator and before liquid separation. Temperature and pressure sensors may also be used at different points in the system to continuously monitor reactor and line conditions.

The process controller 62 computes the amount of recycle, H2 makeup gas, and other operating conditions to optimize the performance of the reactor 28 catalyst and the electricity generator 54. The computations are preferably based on chemical thermodynamic and energy models and advanced learning algorithms (e.g. neural networks) programmed into the controller system.

The process controller sends control signals to automated valves, the hydrogen generator and the syngas generator to alter operating conditions to control the gas composition. Likewise, compressors and temperature control devices and associated sensors are controlled by the controller computer 62 to maintain optimum pressure, temperature and flow rates of syngas over the catalysts in the reactors 28. Accordingly, the controller subsystem 52 can maximize the output production of electricity and liquid products as well as the efficiency of each of the subsystems through monitoring and controlling gas production and reaction conditions.

In use, the embodiment of FIG. 2 provides a continuous input and output system that utilizes carbonaceous fuel and produces electricity, liquid products, steam and chilled water. A carbonaceous fuel 18 is continuously fed into a syngas generator 16. The syngas generator 16 includes technologies that convert carbonaceous fuels (e.g. agricultural, forest and municipal waste; natural gas, coal, oil shale and oil sands) into syngas such as pyrolysis, gasification, reforming, catalysis and other relevant processes. The syngas 20 is composed primarily of CO, H2, and lesser amounts of CO2 and CH4. The syngas generator system 14 may also include various gas cleanup devices to remove contaminants from the syngas including scrubbers, precipitators, etc. In this embodiment, process electricity 68 and product gas 42 can be used to operate the syngas generator system 14. In other embodiments, additional energy can be supplied to the syngas generator from an external fuel source.

Syngas exits the syngas generator 16 and may be combined with a quantity of hydrogen gas from a hydrogen generator 24. In this embodiment, the hydrogen generator 24 is an electrolysis generator that utilizes process electricity 68 to generate H2 gas from water. The hydrogen is combined with the syngas 20 to adjust the ratio of H2 to CO for preferred catalyst performance. The amount of hydrogen added is determined by monitoring the gas composition with continuous gas analyzers 22 and 64 and comparing that composition with the optimum composition from algorithms and information from the process control computer subsystem 52.

A compressor 26 increases the pressure of the combined feed gas to reaction pressure. In one embodiment, the compressor 26 is powered with process electricity 68 or from steam/electricity generated from the exothermic reaction of the catalyst reactors in the alternative. In other embodiments, the compressor 26 or 34 can be powered by syngas or an external fuel source. The feed gas 30 is combined with recycled gas 37 and the combined stream enters the catalyst reactors 28. The catalyst reactors 28 can be any type of pressurized catalytic system. The catalyst reactors 28 contain a catalyst or multiple catalysts that have been selected for the conversion of syngas to products such as alcohols, gasoline and diesel fuels. The input gas 30, containing primarily CO, H2, CO2 and CH4, is partially converted to the products and other non-reactive gases within the catalyst reactors 28.

The catalyst output gases 36 are directed to a gas/liquid separator 38 that operate at pressures just below that of the synthesis catalyst reactor 28 operating pressures. In this embodiment, liquids are condensed by reducing the temperature with chilled water from chiller 60. These liquids 40 are directed to product storage tanks from which they can be distributed. In other embodiments, liquids 40 may be subject to on-site or off-site water removal, separation and refinement if needed to provide purified products.

Gases from the gas/liquid separator 38 may be split at valve 44 and a portion is re-compressed up to the operating pressure of the synthesis catalysts by compressor 34, and recycled back to the catalyst reactor 28 to further convert the reactive species. The other portion, called the product or purge gas 42, is directed to valve 66, where a fraction 46 is directed to the syngas generator 16 to provide process energy and the other fraction 48 is directed to compression ignition gas engines or turbines 54. The mechanical energy from each gas engine or turbine operates a generator 56 to produce electrical power and heat. Compared to the original syngas, this product gas 42 contains higher concentrations of combustible, but non-catalytically reactive gases (like CH4). This enriched gas improves the thermal energy conversion efficiency of gas engines and gas turbines.

Electrical power from the generators 56 is connected to an electrical distribution system 68. A portion of the electrical power may be utilized by the hydrogen generator process 24 and the net power is supplied to an external grid as an additional product.

In this embodiment, heat from the engine and engine exhaust is converted to chilled water 60 and steam 58 to be utilized in the process or co-located cogeneration facilities.

A process controller 52 subsystem controls the production process. This process controller is typically computer based, but analog controllers can also be utilized alone or in combination with computer based systems. In FIG. 2, the process controller 62 controls the gas recycle at valves 44 and 66 and the addition of H2 to the gas feed to the catalyst reactors 28 to optimize performance. A continuous gas analyzer 22 quantifies the amount and composition of the syngas from the syngas generator 16 and reports this information to the process controller 62. Another continuous gas analyzer 64 quantifies the amount and composition of the gas exiting the catalysts 28 after the pressurized gas/liquid separator 38. The process controller 62 computes the amount of gas to recycle based on a process model and sends a control signal to the split valves 44 and 66. The process controller 62 also computes the amount of makeup H2 needed for optimal catalyst performance and sends a control signal to the hydrogen generator 24.

The invention may be better understood with reference to the accompanying examples, which are intended for purposes of illustration only and should not be construed as in any sense limiting the scope of the present invention as defined by the claims appended hereto. The following examples demonstrate the productivity and efficiency of this invention for the conversion of syngas to various liquid fuel products. These examples are shown utilizing particular inputs, formulations, reaction conditions, and efficiencies as illustrations in order to make the present invention more understandable.

EXAMPLE 1 Production of Syngas and Fuels

In Example 1, a pyrolysis/steam reforming system is operated in the absence of oxygen or air to produce syngas with an average molar composition of 35% H2, 28% CO, 18% CO2 and 18% CH4 (Table 1).

Continuous Gas Analyzers (22 and 64) in FIG. 1 and FIG. 2, specifically mass spectrometers in this example, are used to obtain real-time measurements by monitoring the molecular peaks of the gas-phase species listed in Table 1 before (BC) and after the catalyst reactors (AC). The syngas generator for this example utilizes pyrolysis/steam reforming thermochemical process in the absence of oxygen or air. Since nitrogen has the same nominal mass as carbon monoxide (m/e: 28) and oxygen has the same nominal mass as methanol (m/e: 32), the presence of nitrogen and oxygen could cause an error in the quantitative measurement of carbon monoxide and methanol. Therefore, the initial concentrations of the gas-phase species, listed under FPS Operation (Initial Conditions), were measured using gas chromatography and gas chromatography/mass spectrometry. It was found that nitrogen (0.4 Mole %) and oxygen (0.05 Mole %) were very low and therefore these species will not interfere with the carbon monoxide and methanol measurements using the on-line mass spectrometer. Tables 1 and 2 illustrate the results for the process optimization of syngas to alcohol conversion efficiency and ethanol/methanol production selectivity using a MoS2/K2CO3:La2O3/Y2O3 catalyst as an example. This example represents one gas recycle.

The initial catalyst conditions are presented in Table 1. The hydrogen generator was used to add enough extra hydrogen to increase the H2/CO from 1.25 to 1.69. It is observed that hydrogen and carbon monoxide is decreased as a result of reactions over the catalyst with the subsequent production of methanol, ethanol and propanol. The CO conversion efficiency is 30.8% and alcohol product consisted of 48.9 wgt. % ethanol/48.5 wgt. % methanol and 2.6 wgt. % propanol.

After 60 minutes of data collection, changes in catalyst process conditions, the computer model determines that the space velocity should be decreased from 9000 hr−1 to 5500 hr−1 and the catalyst reactor temperature increased to 500° F. This change results in a slight decrease in the CO conversion efficiency (30.8% to 29.2%) but the selectivity of ethanol to methanol is increased (57.5 wgt. % ethanol/37.9 wgt. % methanol) with a small increase in propanol (4.6 wgt. %).

After another 90 minutes of process changes in catalyst conditions, the computer model determines that the maximum CO conversion efficiency and ethanol/methanol selectivity has been achieved. The optimum CO conversion efficiency is 36.0%, and the alcohol selectivity is 66.1 wgt. % ethanol/28.3 wgt. % methanol) with an acceptable increase in propanol (5.6 wgt. %).

This computer-controlled optimization process is not limited to the production of ethanol but equally applicable to the production of other fuels and chemical feedstocks such as other alcohol fuels, diesel, dimethyl ether and gasoline.

In the next three examples, the output of a plant that generates and converts a syngas feed of 500,000 standard cubic feet (SCF) per hour is used. The average molar composition of the syngas is 38% H2, 23% CO, 23% CO2 and 15% CH4. For comparative purposes, it is estimated that this syngas could be generated from pyrolysis/steam reforming of 10 tons per hour of 8500 BTU/lb wood waste, or pyrolysis/steam reforming of 9 tons per hour of 9500 BTU/lb of sub-bituminous coal, or partial oxidation/steam reforming of 150,000 SCF per hour of stranded natural gas at 1000 BTU/SCF. For these examples it is assumed that the syngas generation unit must be supplied with supplemental product gas and electricity resulting in an overall thermal efficiency of 70%.

Examples 2 through 4 demonstrate that the system described in this invention can give commercially reasonable quantities of products using conventional catalysts. Further, this system uses a minimal amount of capital equipment relative to other systems for producing similar liquid fuel products at much larger scales not viable for small and medium sized distributed systems.

EXAMPLE 2 Production of Methanol

In order to demonstrate the production of one liquid product and electricity with the system shown schematically in FIG. 2, the catalyst of the reactor 28 was selected to produce methanol. The catalyst used in the synthesis reactor 28 was a Cu—Zn based catalyst used for methanol synthesis. Table 3 shows the operating conditions for this system including catalyst pressure, reactor temperature, CO conversion, and selectivity. In addition, Table 3 summarizes the resulting outputs and efficiencies for this system with a syngas input of 500,000 SCF per hour. The productivity of the plant is shown for three different recycle rates (0%, 75%, and 90%) to demonstrate the range of operating conditions and product mixes.

It can be seen that the synthesis of liquid fuels alone gives lower (9%-37%) thermal conversion efficiencies that are particularly pronounced at lower recycle rates. The combined production of fuel and electricity also provides a higher thermal efficiency than seen with the direct production of electricity from the syngas, which is about 28% when using the best available technologies for electricity production. The combined liquid fuel synthesis and electricity generation described in this example increases thermal conversion efficiencies to approximately 48%, resulting in greater product yields and concurrent increased economic benefits.

EXAMPLE 3 Production of Mixed Alcohols 80% Ethanol, 15% Methanol, 5% C3+Alcohols

This example uses a multi-layered catalyst combination based on a promoted Cu—Zn and a promoted Group VIII metal catalyst to produce a mixture of alcohols containing primary ethanol.

Table 4 shows the operating conditions for this system including catalyst pressure, reactor temperature, CO conversion, and selectivity. In addition, this table summarizes the resulting outputs and efficiencies for this system with a syngas input of 500,000 SCF per hour. The productivity of the plant is shown for three different recycle rates (0%, 75%, and 90%) to demonstrate the range of operating conditions and product mixes.

The productivity and efficiency for the production of ethanol and electricity seen in Example 3 is similar to that shown Example 2 for a product stream with a higher energy density. This product stream of ethanol may be more suitable for fuel applications or more desirable for economic reasons.

EXAMPLE 4 Production of Diesel Syncrude

Low temperature Fischer-Tropsch synthesis catalysts have been developed to produce liquid hydrocarbons useful for producing high quality diesel fuel and other products. Both Fe and Co based catalysts have been used for this purpose. For this example, a Fe based catalyst promoted with K and Cu is used in a tubular-type reactor for the production of primarily C5+ olefins and paraffins. Table 4 shows the operating conditions, the resulting outputs and efficiencies for this system with a syngas input of 500,000 SCF per hour. The productivity of this system is shown for three different recycle rates to demonstrate the range of product mixes.

It can be seen in this example that because of the high conversion rate of CO over the catalyst, fewer recycle loops are needed to produce an ideal production level of fuel. The combined thermal efficiency of 47% for the integrated process results in greater product yields and concurrent economic benefits than the current best available technologies. These three examples demonstrate clear commercial benefits of this invention for the combined production of liquid fuels, electricity and heat from carbonaceous feedstocks.

Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”

TABLE 1 Gas Composition (Mole %) FPS1 FPS FPS Operation Operation Operation Gas-Phase (Initial Conditions) (60 min) (150 min) Species MW SI* BC** AC*** BC** AC*** BC** AC** Hydrogen 2 35 44 31 42 29 41 27 Methane 16 18 15 15 18 19 18 19 Carbon 28 28 26 18 24 17 25 16 Monoxide Nitrogen 28 0.4 0.4 0.4 0.5 0.5 0.5 0.05 Ethane 30 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Methanol 32 0.00 0.00 10.7 0.00 9.2 0.00 7.5 Oxygen 32 0.05 0.05 0.00 0.00 0.00 0.00 0.00 Carbon 44 18 15 16 16 16 16 17 Dioxide Ethanol 46 0.00 0.00 7.5 0.00 9.7 0.00 12.2 Propanol 60 0.00 0.00 0.3 0.00 0.6 0.00 0.8 Benzene 78 0.01 0.01 0.01 0.02 0.02 0.03 0.03 Toluene 92 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Total — 99.50 100.50 98.9 100.5 101.0 101.5 99.6 *SI: Syngas Input; **BC: Before Catalyst Reactor; ***AC: After Catalyst Reactor 1FPS Operation (Initial Conditions) Temperature: 450° F.; Space Velocity: 9000 hr−1; Pressure: 750 psi 2FPS Operation (60 min) Temperature: 500° F.; Space Velocity: 5500 hr−1; Pressure: 750 psi 3FPS Operation (150 min) Temperature: 575° F.; Space Velocity: 4000 hr−1; Pressure: 650 psi

TABLE 2 Results for the Process Optimization of Syngas to Alcohol Conversion Efficiency and Ethanol/Methanol Production Selectivity Using a MoS2/K2CO3:La2O3/Y2O3 Catalyst in the Fuel Production System (FPS) FPS Operation FPS FPS Parameter/Product (Initial Operation Operation Optimized Conditions) (60 min) (150 min) CO Conversion 30.8 29.2 36.0 Efficiency (%) Ethanol (Wgt. %) 48.9 57.5 66.1 Methanol (Wgt. %) 48.5 37.9 28.3 Propanol (Wgt. %) 2.6 4.6 5.6

TABLE 3 Example 2: Production of Methanol and Electricity Operating Conditions: Synthesis Catalyst Promoted Cu—Zn Pressure (psi) 700 Temperature (° F.) 510 CO Conversion (%) 15 Selectivity (mol % C): Methanol 95 CH4 2 CO2 2 Plant Productivity: Recycle Rate (%) 0 75 90 Methanol (gal/hr) 230 632 975 Net Electricity (MW) 12.1 8.6 5.6 Efficiency (%) Liquid Fuel Only 9 24 37 Liquid Fuel + Electricity 33 41 48

TABLE 4 Example 3: Production of Mixed Alcohols and Electricity* Operating Conditions: Synthesis Catalyst Layered Cu—Zn and Group VIII Pressure (psi) 750 Temperature (° F.) 500 CO Conversion (%) 30 Selectivity (mol % C): Mixed Alcohols* 74 CH4 20 CO2 5 Plant Productivity: Recycle Rate (%) 0 75 90 Mixed Alcohols 260 548 703 (gal/hr) Net Electricity (MW) 9.6 6.0 4.1 Efficiency (%) Liquid Fuel Only 13 27 37 Liquid Fuel + Elec. 32 39 45 *Product distribution is 80% Ethanol, 15% Methanol, 5% Other Alcohols

TABLE 5 Example 4: Production of Diesel Syncrude and Electricity Operating Conditions: Synthesis Catalyst Fe Promoted with Cu and K Pressure (psi) 300 Temperature (° F.) 450 CO Conversion (%) 80 Selectivity (mol % C): Liquid Hydrocarbons* 82 CH4 5 CO2 12 Plant Productivity: Recycle Rate (%) 0 75 90 Diesel Syncrude 435 511 530 (gal/hr) Net Electricity (MW) 4.6 3.1 2.7 Efficiency (%) Liquid Fuel 34 40 41 Liquid Fuel + Elec. 43 46 47 *Product distribution is 85% C5+ hydrocarbons, 60-80% olefinic, at 140,000 BTU/gal, well suited for high quality low-sulfur diesel fuel

Claims

1. A process for the continuous production of electricity, heat and syngas derived products, comprising:

converting biomass or fossil fuels to a stream of synthesis gases;
analyzing characteristics of said stream of synthesis gases;
supplementing said stream of synthesis gases with hydrogen gas from a source of hydrogen gas to produce a supplemented stream of synthesis gas with a regulated composition;
reacting the supplemented synthesis gas stream with catalysts selected to convert carbon monoxide and hydrogen to reaction products to produce a stream of reaction products and unreacted synthesis gases;
separating reaction products from the unreacted synthesis gases; and
combusting the unreacted synthesis gases to produce electricity and heat.

2. A process as recited in claim 1, further comprising:

mixing a portion of the unreacted synthesis gases with said supplemented stream of synthesis gases; and
recycling said mixed gas stream through the catalyst for at least one cycle,
wherein the conversion efficiency of reactive gases to products is maximized.

3. A process as recited in claim 1, further comprising:

monitoring of the characteristics of the pre- and post-catalyst gas stream;
optimizing a ratio of recycle gas with synthesis gas to provide a synthesis gas stream that has approximately the highest reaction efficiency with the catalysts; and
concentrating said recycled unreacted gas stream gases prior to combustion.

4. A process as recited in claim 3, further comprising:

using software models to analyze said monitored gas characteristics to establish optimum operating conditions; and
controlling temperature, pressure, space velocity, chemical composition and recycle rates of said pre- and post catalyst synthesis gas streams.

5. A process as recited in claim 1, further comprising:

converting carbon dioxide gas in said synthesis gas stream to carbon monoxide gas.

6. A process as recited in claim 1, wherein said hydrogen source is generated by electrolysis of water with electricity generated by the system.

7. A process as recited in claim 1, further comprising:

producing steam from excess heat from combustion, catalytic reactor and synthesis gas production to produce steam; and
generating electricity from the steam, thereby increasing the energy efficiency of the entire system.

8. A process as recited in claim 1, further comprising:

using a portion of the excess heat from combustion of said unreacted synthesis gases for gasification of carbonaceous feedstock.

9. A process as recited in claim 1, further comprising:

using a portion of the excess heat from combustion of said unreacted synthesis gases for an absorptive chiller used to provide chilled fluids for a condenser to separate reaction products from a post catalyst gas stream.

10. A process as recited in claim 1, further comprising:

controlling compressors, valves and flow rates of gas with a process controller and sensors.

11. A process for the continuous production of electricity, heat and syngas derived products, comprising:

generating synthesis gas stream from a carbonaceous feedstock;
reacting the synthesis gas stream with catalysts selected to convert carbon monoxide and hydrogen to reaction products to produce a stream of reaction products and unreacted synthesis gases;
separating reaction products from the unreacted synthesis gases;
splitting said unreacted synthesis gases into two streams;
recycling a portion of unreacted synthesis gases through said catalysts for at least one cycle;
combusting a portion of the unreacted synthesis gases;
monitoring pressure, temperature, gas composition and flow rates of the synthesis gas flow and recycled synthesis gas flow with sensors;
controlling the pressure, temperature, gas composition and flow rates of the synthesis gas flow and recycled synthesis gas flow and output of reaction products and electricity with a process controller; and
producing steam with excess heat from a gas combustion chamber.

12. A process as recited in claim 11, further comprising:

analyzing continuously said stream of synthesis gases and recycled gases; and
supplementing said stream of gases with hydrogen gas from a source of hydrogen gas to produce a supplemented stream of synthesis gas with a regulated ratio of hydrogen to carbon monoxide.

13. A catalytic reactor, comprising:

a reaction vessel with at least one reaction chamber and an intake duct and an output duct;
a first hydrogenation catalyst;
a carbonylation catalyst; and
a second hydrogenation catalyst,
wherein gas containing carbon monoxide and hydrogen entering through said intake duct can pass sequentially through each catalyst and through the output duct.

14. A catalytic reactor as recited in claim 13, further comprising:

means for heating gasses within said reaction vessel.

15. A catalytic reactor as recited in claim 13, further comprising:

a catalyst support carrier.

16. A catalytic reactor as recited in claim 15, wherein said support carrier is a carrier selected from the group of carriers consisting essentially of aluminum oxide, silica, a zeolite, titanium oxide, metal and clay.

17. A catalytic reactor as recited in claim 13, wherein said first hydrogenation catalyst is a catalyst selected from the group of catalysts consisting essentially of Cu, Zn, Mo, Ni, or Fe.

18. A catalytic reactor as recited in claim 13, wherein said hydrogenation catalyst further comprises an alkali metal promoter, selected from the group of promoters consisting essentially of Ti, Zr, Pd, and Mn.

19. A catalytic reactor as recited in claim 13, wherein said carbonylation catalyst comprises at least one Group VIII metal and at least one co-catalyst.

20. A catalytic reactor as recited in claim 13, wherein said co-catalyst comprises yttrium metal, a lanthanide series metal or an actinide series metal.

Patent History
Publication number: 20100175320
Type: Application
Filed: Dec 28, 2007
Publication Date: Jul 15, 2010
Applicant: PACIFIC RENEWABLE FUELS LLC (Sacramento, CA)
Inventors: Dennis Schuetzle (Grass Valley, CA), Ronald G. Hurley (Sarasota, FL), Robert W. Schuetzle (Sacramento, CA)
Application Number: 11/966,788
Classifications
Current U.S. Class: Producers (48/76); Producer (48/203)
International Classification: C10J 3/00 (20060101);