This application relates to a clean energy system, a renewable energy system or a zero emission energy system (ZEES), and more particularly to a chemical principle based power plant (CPPP) with CO2 waste utilization.
The governmental efforts to curb greenhouse gas (GHG) emissions have been relying on the laws of individual countries and states for some time now. In general, most countries and states share the interim goal of reducing GHG emissions to 25% below 1990 levels by 2020, and an overall goal of 80% by 2050. However, it is reported that the goals are unlikely to be met by a large margin unless revolutionary technologies are developed in the near future.
When petro-fuel is used with energy systems, carbon credits may be calculated and applied to finance the project due to favorable system hardware characteristics for emission reduction. When renewable fuel is employed, additional carbon credits are calculated due to fuel characteristics. Thus, the potential exits for compounding carbon credits associated with renewable fuel systems, which may be viewed as such systems having a negative CO2 footprint.
The clean technology may also receive renewable energy credits (REC) administered by agencies of respective countries and states. The REC may only be applied based on the type of fuel used. Fuel cell systems, judged according to their operational principles, do not have renewable characteristics.
The present application provides a clean energy system, a renewable energy system or a zero emission energy system (ZEES) with CO2 waste utilization. This application utilizes chemical principles for concurrent power generation and energy conversion to eliminate CO2 emissions from power plants and introduce new sources of liquid fuel for transportation. The energy system provided in the present application solves the two most serious problems in the current energy industry: petro-fuel shortage and global warming due to greenhouse gas (GHG) emissions. In one embodiment, the clean energy system is a zero emission energy system when a carbon containing stream with a matched amount of H2 is used for liquid fuel production and H2 alone is used for power generation. When employing a renewable feedstock, the energy system constitutes negative CO2 footprints thus potentially gaining double carbon credits.
According to one practice of the present invention, clean power is generated and any greenhouse gas (GHG) produced by the system is retained and employed to help produce high valued fuels. The energy system provided in the present application may be properly sized for any installation, converting available municipal solid waste (MSW) or biomass into clean energy at affordable costs and with low carbon footprints. The energy system may be applied equally to feedstock including coal and other solid hydrocarbon fuels.
In one embodiment, the energy system may include a fuel processor, an energy catalytic reactor, and a power generator. The fuel processor catalytically converts the CH4 component in the natural gas, biogas or syngas into a reformate including H2, CO, CO2 and H2O species. The energy reactor may convert the reformate in gas form into a liquid fuel. The power generator may generate power using an output of the fuel processor and/or an output of the energy reactor.
In an embodiment, the fuel processor may include a partial oxidation, autothermal and steam methane reformer. The reformate may be processed with a water shift process to have different percentages of CO vs. CO2 with a variation range between about 0% and about 20%. The reformate of the fuel processor may be processed with a pressure swing adsorption process to form two flow streams: 1) high purity H2 steam; 2) high concentration of carbon (CO, CO2) contents. The CO2 may be processed with the water shift process to the maximum level of 20%, and processed through the pressure swing adsorption to result in a concentrated CO2 stream. The concentrated CO2 stream may be applied for Enhanced Oil Recovery (CO2-EOR) on-site at oil wells.
In an embodiment, the H2, CO and CO2 produced from the fuel processor may be processed in the energy reactor into methanol (CH3OH) in liquid form with a methanol synthesis catalyst. The methanol may be further processed in the energy reactor into DME (CH3OCH3) in liquid form with a suitable catalyst. The DME may be further processed in the catalytic energy reactor into gasoline in liquid form with another suitable catalyst. The mixture of H2, CO2 and CO derived from the renewable feedstock may be carried out for producing jetfuel, propane, diesel or heavy liquid fuel production due to high concentration of CO2, co in the syngas.
According to the teachings of the present invention, the clean energy system may be operated to maximize the use of carbon for the production of a) liquid bio-fuels, including methanol, ethanol, propanol and butanol, as well as b) liquid synfuels, including DME, gasoline, propane, butane, jet fuel and diesel. The energy reactor utilizes chemical-catalysts or bio-catalysts. The energy reactor may be a chemical-catalyst bed, such as a fixed bed, structured bed, slurry bed or microchannel with integrated heat exchanger. The energy reactor may employ single functional catalysts, bifunctional catalysts or multi-functional catalysts to achieve improved performances. The energy reactor may employ bio-catalysts including varieties of yeasts, bacteria and enzymes.
In an embodiment, the reformate may be applied for power generation in one of the following fuel cell electric generators including solid oxide fuel cell (SOFC), molten carbonate fuel cell (MCFC), proton exchange membrane fuel cell (PEMFC), phosphoric acid fuel cell (PAFC) and alkaline fuel cell (AFC). The SOFC is applied in one of three devices: a solid oxide fuel cell; a hybrid system composed of a solid oxide fuel cell and gas turbine unit; a hybrid system composed of a solid oxide fuel cell and a steam turbine unit. The reformate may be applied for power generation in one of the following generators including an internal combustion engine, gas turbine, or steam turbine.
In an embodiment, the reformer may be a Hybrid Reforming System involving electric energy input obtained from a Photovoltaic (PV) panel, wind or tidal wave to meet the energy demands for the reformer's endothermic thermal input and the reformate compression process. The clean energy system may be a Hybrid System involving electric energy input obtained from the PV, wind and tidal wave to support the energy demands for the system, as well as provide remedy for the intermittency of these power sources with storage capability in the form of liquid fuel of the production.
In an embodiment, the clean energy system may be applied to use renewable feedstock that includes municipal solid waste, municipal sewage, farm animal waste, biomass and woody biomass with a feedstock processor. The municipal sewage and farm animal waste may be first processed through digester to yield biogas, which includes methane CH4, CO2 and CO. The municipal solid waste, farm biomass, woody biomass may be first processed through gasifier to yield syngas which includes methane CH4, CO2 and CO.
In an embodiment, the feedstock processor may be a syngas generator, including a thermal driven, plasma or microwave driven gasifier. The feedstock processor may be a syngas generator, classified as a volatilizer referred by Hathaway Renewable Energy, Inc. of Tennessee. The volatilizer provides syngas of CH4 rich having heating value exceeding 500 Btu/ft3, other than a gasifier of a common choice providing syngas of H2 rich with heating value typical of 300 Btu/ft3. The biomass feedstock may include forest waste, community (municipality) waste, coal of solid phase which passing through the volatilizer yields syngas with the heating value over 500 Btu/ft3 composed of CH4, H2, CO, CO2 and other secondary species and biochar or charcoal as the solid residual. The biochar has commercial value as the activated charcoal for commercial use; and claiming for carbon credits and renewable energy credits.
In an embodiment, the biomass feedstock may include waste of liquid phase or sludge which passing through the volatilizer yields syngas with the heating value over 500 Btu/ft3, composed of CH4, H2, CO, CO2 and other secondary species of solid residual. The volatilizer may process the biomass under physical step without undergoing combustion, rather undergoing heating by external sources. The external heating source may be derived from the recycled portion of the syngas, which provides clean burn high temperature source of heat above 1000° C. The external heating source may be derived from the high temperature waste stream, 800° C. to 1000° C., of the SOFC power generator or the high temperature waste stream, 600° C. to 800° C., of the hybrid power generator. The volatilizer operates at a temperature within the above range of the heat sources.
The foregoing and other objects, features and advantages of the invention will be apparent from the following description and apparent from the accompanying drawings, in which like reference characters refer to the same parts throughout the different views. The drawings illustrate principles of the invention.
The produced H2 may be used for a solid oxide fuel cell (SOFC) system. Fuel cells produce clean exhaust without SOx or NOx through an electrochemical process rather than a thermodynamic process as used in traditional combustion systems. The SOFC also has an advantage in that its clean exhaust remains at a high temperature, which is suitable to drive a traditional system for additional power generation. The overall exhaust remains clean while the power output or the system efficiency doubles.
The SOFC may be integrated with heating, ventilation and air conditioning (HVAC) systems to perform functions for human comfort using the hot exhaust from the SOFC. When energy cost rises, the SOFC-HVAC system may be made available to serve families and communities with a single system performing all necessary power generation functions.
A Zero Emission System (ZES) is employed to make use of CO2 from the HECP system, in which the hydrogen is fully utilized while the CO2 is exhausted to the air as unwanted emissions. CO2 is produced in the HECP system in a concentrated stream for subsequent collection. In one embodiment, the CO2 gas may be used for injection into an oil field or well to enhance oil production. The CO2 gas may be compressed for CO2-EOR (Enhanced Oil Recovery). This may provide opportunities for all small and medium field owners to enjoy the benefits of CO2 in their wells, in areas of absence of natural CO2 supply services typically available only to large field owners. The well-known technique of horizontal drilling when coupled with CO2 injection may provide a deeper and wider reach into the earth with further benefits in thorough sweeping of the sand grains by CO2 action for enhanced oil production.
An embodiment of the present invention provides a zero emission energy system (ZEES) for eliminating the CO2 emissions from the traditional power plants and introducing new sources of liquid fuel for transportation. The embodiment utilizes chemical principles for concurrent power generation and energy conversion. The fuelstock is first treated before the power generation to assure clean emissions. The hydrocarbon fuel, either from a petro-source or from a bio-source, is processed following the steam methane reformer reaction into H2, CO, CO2 and H2O, and collectively constitute the reformate. The reformate may be separated into two gas streams: 1) H2 stream; 2) carbon containing stream. The H2 stream is primarily utilized for power generation that emits only H2O (e.g., water molecules). The carbon stream when combined with the proper amount of H2 from the H2 stream may be catalytically reacted to form liquid fuels, such as methanol (CH3OH). Other liquid fuel species may be further derived with suitable catalysts. The energy system may provide solutions to simultaneously cure the problems in the current energy industry: petro-fuel shortage and global warming due to greenhouse gas (GHG) emissions. In the energy system, the clean power is generated and the greenhouse gas CO2 is retained and applied for the production of high valued fuels.
The ZEES provides the energy industry the following benefits: ZEES provides storage solutions to the Solar Electric projects in liquid chemicals; ZEES provides sweeping solution to power generation of emissions issues; ZEES promotes global oil production to relief international political worries; ZEES as GTL facilitates the natural gas move in convenient liquid forms; ZEES as BTL facilitates the renewable bio-feedstock to become commercial energy source; ZEES as a chemical reactor to process petro fuel or biofuel with equal effectiveness; ZEES hybridizing with renewable electricity for storage better serve the future Smart Grid; ZEES thus provides an unhurried transition to better fuel choices.
The energy system 100 may include a fuel processor 120, such as a reformer, an energy catalytic reactor 130, and a power generator 140. The fuel processor 120 can be a reformer that converts a renewable feedstock, such as methane rich gas, into a reformate including H2, CO and CO2, which in turn can be introduced to a fuel cell, such as a solid oxide fuel cell (SOFC). Within the reformer, any sulfur present in the reactant may be removed. Reactant pressure may be adjusted. The water may be treated for deionization to prevent corrosion to the equipment in the system and to precondition the reactant for clean emissions. The reformate outputted by the fuel processor 120 may be processed into two separate streams, the H2 rich stream and the carbon containing CO and CO2 stream.
The energy catalytic reactor 130 converts H2 with CO and CO2 into liquid form of chemical under catalytic reaction according to well-known techniques. Methanol has been recognized as a fundamental liquid chemical derived from syngas or biogas with a commercially available methanol catalyst reactor. Methanol may be further processed into various levels of alcohols, such as ethanol, pentanol, butanol and various commercial fuels such as gasoline, jet fuel and diesel. Gaseous fuel species are difficult to transport or distribute from production plants to the market place. Thus, it is desirable to be able to convert it into liquid form for storage as well as for shipping to market. It also gains the advantage of being used as the fuel for transportation, or vehicle fuels.
The power generator 140 may use the H2 rich stream derived from the reformer 120 to generate power, a byproduct of which is water. It is a desirable and efficient mode for power generation. The traditional power generators, such as internal combustion engines, gas turbines and steam turbines, may also be powered by the H2 gas stream. Fuel cells are a suitable generator class on H2 fuel. The energy system 100 transforms various input gases, such as natural gas, syngas or biogas, into hydrogen rich gas that may be used by the electrochemical reaction of the fuel cell. The Gas Turbine (GT) portion of the hybrid SOFC-GT is capable of reusing the SOFC exhaust to boost the overall efficiency of the combined cycle system to about 70%.
The zero emission energy system (ZEES) may further be applied in renewable applications when a renewable feedstock processor 110 is added prior to the fuel processor 120. Volatilization involves the latest generation of converting organic matter into synthetic gas and biochar. The volatilization process is simpler and cleaner than the previous generation “gasification” technology. Early generation gasification technology uses high temperatures and sometimes high pressure to reformulate matter into the desired components. The process is very complex and has a high parasitic energy cost. Volatilization uses indirect heat in an oxygen starved environment to enable biomass to decompose into methane (45%), CO (15%), H2 (15%) and other hydrocarbons. The resultant syngas is a very clean product with a LHV greater than 600 Btu/scf which is a factor of two times more energy density than the previous technology. The volatilization units utilized in this embodiment are modular and may be stacked to scale the process in 2.5 MW increments. Each volatilization unit may process 30 tons per day (TPD) of MSW or biomass that contains less than 20% moisture. The volatilizer may also be trailer mounted to produce syngas for transportable requirements. This volatilizer may equally be applied to other feedstock, including coal and all other solid hydrocarbon fuels.
The fuel processor 320 may be a partial oxidation, autothermal or steam methane reformer. The steam methane reformer provides the best performance for pure hydrogen production, if steam supply is unrestricted. A water shift processor following the reformer may be controlled by a processor (not shown) to have a different percentage of CO vs. CO2 in a range from about 0% to about 20%.
The above reactions are expressed as:
CH4+H2O→3H2+CO Steam Methane Reforming
CO+H2O→CO2+H2 Water Gas Shift Reaction
The reformate may be further processed in a pressure swing adsorption process into two streams of flows: 1) high purity H2 steam; 2) high concentration of carbon (CO, CO2) contents.
When the reformate is processed in the water shift processor to the maximum level of 20% with low or trace amounts of CO, it may be further processed through the pressure swing adsorption process to yield a concentrated CO2 stream. The concentrated CO2 stream may be applied for Enhanced Oil Recovery (CO2-EOR) on-site at oil wells, as shown in
The liquid chemical production branch 321 carries a mixture of H2, CO and CO2 which is introduced into the energy reactor 331 via a heat exchanger 322, a condenser 323, a compressor 324 and a heat exchanger 325 for the production of liquid methanol (CH3OH) with a methanol synthesis catalyst. The condenser 323 may extract water from the reformate and the compressor 324 compresses the reformate before it enters the heat exchanger 325. The methanol may be further introduced into a second energy reactor 332 via a heat exchanger 333, a compressor 334 and a heat exchanger 335 for production of DME (CH3OCH3) in liquid form with a suitable catalyst. The DME as produced may be further processed in a catalytic energy reactor into common gasoline in liquid form with suitable catalyst. The DME or gasoline may be sent to the storage 341 via a heat exchange 336.
The above reactions can be expressed as:
2H2+CO→CH4O Methanol Synthesis
2CH4O→CH3OCH3+H2O Dimethyl Ether (DME) Synthesis
The zero emission energy system 300 may be operated to maximize the use of carbon for the production of, a) liquid bio-fuels, including methanol, ethanol, propanol and butanol, as well as b) liquid synfuels, consisting of DME, gasoline, propane, butane, jet fuel and diesel.
The energy reactor 331 or 332 utilizes chemical-catalysts or bio-catalysts respectively. The energy reactor 331 or 332 employs chemical-catalyst bed in one of the various possible configurations including a fixed bed, structured bed, slurry bed and microchannel with integrated heat exchanger. The microchannel reactor may be of a cylindrical configuration. The energy reactor 331 or 332 may employ single functional catalysts, bifunctional catalysts or multi-functional catalysts to achieve improved performances. The bifunctional or multi-functional catalysts are formed by thorough mixing of basic compounds of individual catalysts, resulting in near instant chained-reactions without unnecessary time lapse. This innovation helps to reduce the size and the number of the reactors, thus leading to cost reduction in system construction. The energy reactor 331 or 332 may also employ bio-catalysts consisting of varieties of yeasts, bacteria and enzymes.
The H2 stream 322 may be applied for power generation by a power generator 342 with zero CO2 emission by employing fuel cells or other traditional power generators. The fuel cell electric generators may be selected from one of the types from solid oxide fuel cell (SOFC), molten carbonate fuel cell (MCFC), proton exchange membrane fuel cell (PEMFC), phosphoric acid fuel cell (PAFC) and alkaline fuel cell (AFC). The high performance SOFC has three configurations: a solid oxide furl cell; a hybrid system composed of a solid oxide fuel cell and gas turbine unit; a hybrid system composed of a solid oxide fuel cell and steam turbine unit. The traditional power generation consists of one of the following generators selected from internal combustion engine, gas turbine and steam turbine.
Various pump and valves can be employed throughout the system to help regulate or control the flow of the various fluids. These components can be controlled by a controller or processor 350.
The reformer 10 includes a number of thermally conductive plates 12 and reforming plates 14 that are alternately stacked together to form a stacked reforming structure 13 that extends along axis 28. The reformer includes a fluid conduit 16 that is in fluid communication with the inner portions 12A, 14A of the plates 12, 14. The reformer 10 is preferably housed within a gas-tight enclosure or housing 20. The illustrated reformer may be used to perform both steam and oxidation reforming. The heat necessary for the reforming process may be supplied internally by partial oxidation of hydrocarbon fuel or supplied externally by a remote heat source, as shown by wavy lines 26, to the reformer 10 by radiation, conduction or convection.
The reactant to be reformed by the reformer 10 is introduced into the apparatus through the axial fluid manifold 16. The reactant preferably comprises a mixture of a hydrocarbon fuel and a reforming agent, such as air, oxygen, water or CO2, that are premixed either prior to introduction to the manifold 16 or within the reformer. The illustrated reformer 10 includes at least one manifold that delivers a fuel/reforming agent mixture to the reformer, rather than provide separate input manifolds for each gas constituent. The introduction of a premixed reactants to the reformer 10 provides for a relatively simple design.
The reactant mixture 22 is introduced to the manifold 16 by any appropriate means, such as by fluid conduits. The mixture 22 enters the inner portions of the reformer through reactant passages 24 that are formed between the adjacent conductive plates 12 and reforming plates 14. The passages may comprise any surface indentation or protrusions, which may be formed by embossing, and which constitutes a substantially continuous fluid passage that extends from the manifold 16 to the outer peripheral surface 13A of the stacked reforming structure 13. The passages may also be formed by utilizing conductive or reforming plates that are made of a porous material or have a power reformer catalyst material coated or formed thereon, thus allowing the reactant to pass through the reformer.
In an embodiment, the bundle element includes double layers. The space formed between the double layers is designated as the B-side (Circuit B). The space formed between the rolled double layers is designated as the A-side (circuit A). The A-side allows straight flow path along the axis of the reactor with an inflow port 522 and outflow port 524. The B-side presents a spiral flow path between the double layers with an inflow port 518 and outflow port 520. A round screen or perforated plate is placed and secured at the one end (bottom) of the cylinder, which allows the loading of catalyst of proper size to fill the A-side of the reactor when positioned upright for operation. A removable round screen or perforated plate may be placed at the other end (top). The B-side is used as the path for the thermal fluid to flow through for temperature regulation, heating or cooling.
The space between the “double layers” and the space between the “spirally rolled double layers” may be supported by dimples formed in the sheets before welding and rolling. The space may be controlled in millimeter sizes to provide excellent heat transfer capability between the medium on the A-side through the metal layer to the B-side. The rolled configuration presents large surface area to be packaged in small cylindrical volume.
The zero emission energy system 600 may be applied to use renewable feedstock that includes municipal solid waste (MSW), municipal sewage, farm animal waste, biomass and woody biomass with a feedstock processor. The municipal sewage and farm animal waste may be first processed through a digester to yield biogas, which includes methane CH4, CO2 and CO. The municipal solid waste, farm biomass, woody biomass may be processed through a gasifier 610 to yield syngas which includes methane CH4, CO2 and CO.
The feedstock processor may be a syngas generator, selected from a thermal driven, plasma or microwave driven gasifier. A desirable syngas generator classified as a volatilizer 610 provides syngas of CH4 rich having heating value exceeding 500 Btu/ft3, other than a gasifier of a common choice providing syngas of H2 rich with heating value typical of 300 Btu/ft3. The renewable feedstock includes forest waste, community (municipality) waste, coal of solid phase and even waste of liquid phase or sludge which passing through the volatilizer yields syngas and other secondary species including variable amount of biochar or charcoal as the solid residual.
The volatilizer 610 may process the biomass under physical step without undergoing combustion, rather undergoing heating by external sources. The external heating source may be derived from the recycled portion of the syngas, which provides clean burn high temperature source of heat above 1000° C. The external heating source may also derived from the high temperature waste stream, 800° C. to 1000° C., of the SOFC power generator or the high temperature waste stream, 600° C. to 800° C., of the hybrid power generator.
The biochar left behind in volitilizer 610 has commercial value as the activated charcoal for commercial use and may claim for carbon credits and renewable energy credits.
The clean energy system 600 is a zero emission energy system when carbon containing stream with matched amount of H2 is used for liquid fuel production and H2 alone is used for power generation. The system when applied to use renewable feedstock constitutes negative CO2 footprints thus gaining double carbon credits.
Since the reformer is installed on site, this system can greatly enhance the operational income. Furthermore, the CO2 sequestration credit may significantly offset the capital cost of the fuel cell or reformer system, which enhances the financial incentive of the adopting this advanced ZEES system 600 in
As described above, the embodiment in this application utilizes chemical principles for concurrent power generation and energy conversion. The embodiment eliminates the CO2 emissions from the power plants and introduces new sources of liquid fuel for transportation. Therefore, this application provides solutions to simultaneously cure the two most serious problems in the current energy industry: petro-fuel shortage and global warming due to greenhouse gas (GHG) emissions. In the embodiments, the greenhouse gas is retained and applied for the production of high valued fuels. This invention may be applied equally to renewable feedstock and other feedstock including coal and solid hydrocarbon fuels.
It will thus be seen that the invention efficiently attains the objects set forth above, among those made apparent from the preceding description. Since certain changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are to cover generic and specific features of the invention described herein, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
Having described the invention, what is claimed as new and desired to be secured by Letters Patent is:
This application is a Continuation application of U.S. application Ser. No. 14/115,231 filed Jan. 24, 2014, which is a 371 national phase application of International Application PCT/US2012/036640 filed May 4, 2012, which claims priority to U.S. Provisional Application Nos. 61/635,176 filed Apr. 18, 2012, 61/482,495 filed May 4, 2011, and 61/515,900 filed Aug. 6, 2011, the contents of which are hereby incorporated by reference.
Number | Date | Country | |
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61635176 | Apr 2012 | US | |
61515900 | Aug 2011 | US | |
61482495 | May 2011 | US |
Number | Date | Country | |
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Parent | 14115231 | Jan 2014 | US |
Child | 15406142 | US |