Combustion system with fuel cell that produces blue hydrogen

Abstract

A combustion system is provided. The combustion system includes a topping cycle. The combustion system further includes a fuel cell including an anode side, a cathode side, and an electrolyte. The anode side receives fuel via an anode inlet line and produces an anode output product containing a first portion of hydrogen. The cathode side receives an oxidant from the cathode inlet line. The combustion system further includes a separation system having a water gas shift reactor that produces a second portion of hydrogen from the anode output product. The topping cycle is fluidly coupled to the separation system such that the topping cycle receives the hydrogen produced from the anode output product.

Description

[Technical Field]

[0001] The present disclosure relates generally to combustion systems having fuel cells for decarbonizing the system using blue hydrogen produced from the fuel cells. In particular, the present disclosure relates to producing blue hydrogen using fuel cells that can be used for different applications (such as gas turbines). [Background technology]

[0002] A gas turbine power plant, such as a combined cycle power plant (CCPP) or a combined cycle system (CCS), typically includes a gas turbine having a compressor section, a combustion section, a turbine section, a heat recovery steam generator (HRSG) disposed downstream of the turbine, and at least one steam turbine in fluid communication with the HRSG. During operation, air enters the compressor through an intake system and is progressively compressed as it is channeled toward a compressor discharge or diffuser casing that at least partially surrounds a combustor in the combustion section. At least a portion of the compressed air is mixed with fuel and combusted in a combustion chamber defined within the combustor, thereby generating high-temperature, high-pressure combustion gases.

[0003] Combustion gases are routed from the combustor along a hot gas path through the turbine, where they gradually expand as they flow across alternating stages of stationary vanes and rotatable turbine blades coupled to a rotor shaft. Energy is transferred from the combustion gases to the turbine blades, causing the rotor shaft to rotate. The rotational energy of the rotor shaft can be converted to electrical energy via a generator. The combustion gases exit the turbine as exhaust gases, which enter the HRSG. Thermal energy from the exhaust gases is transferred to water flowing through one or more heat exchangers in the HRSG, thereby producing superheated or supercritical steam. The superheated steam can then be routed to a steam turbine and used to generate additional electricity, improving overall power plant efficiency.

[0004] Turbomachinery combustion systems typically burn hydrocarbon fuels, producing air-polluting emissions such as nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO2). Regulatory requirements for low emissions from gas turbines are becoming increasingly stringent, and environmental agencies worldwide are now requiring even lower pollutant emission rates from both new and existing gas turbines. Alternative fuels, such as hydrogen, which produce fewer emissions upon combustion, can be used in place of (or in addition to) natural gas, reducing the production of pollutants in the combustor. However, hydrogen is difficult to obtain and store.

[0005] Therefore, improved systems and methods for operating combined cycle systems that produce fewer emissions are desirable and would be appreciated in the art. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2010 / 0028730 Summary of the Invention

[0007] Aspects and advantages of the combustion systems and methods according to the present disclosure are set forth in part in the description that follows, or may be obvious from the description, or may be learned by practice of the present teachings.

[0008] According to one embodiment, a combustion system is provided. The combustion system includes a gas turbine having a compressor section, a combustion section, and a turbine section. The combustion system further includes a fuel cell including an anode side, a cathode side, and an electrolyte. The anode side receives fuel via an anode inlet line and produces an anode output product. The cathode side receives an oxidant from the cathode inlet line. The combustion system further includes a separation system having a water gas shift reactor that produces hydrogen from the anode output product. The combustion section of the gas turbine is fluidly coupled to the separation system such that the combustion section receives the hydrogen produced from the anode output product.

[0009] According to another embodiment, a method of operating a combustion system is provided. The combustion system has a fuel cell with an anode side, a cathode side, and an electrolyte. The method includes supplying fuel to the anode side of the fuel cell using an anode inlet line. The method further includes supplying oxidant to the cathode side of the fuel cell using a cathode inlet line. The method further includes producing an anode output product containing a first portion of hydrogen using the fuel cell. The method further includes supplying the anode output product from the anode side to a separation system. The separation system includes a water gas shift reactor. The method further includes producing a second portion of hydrogen from the anode output product using the water gas shift reactor. The method further includes removing water and carbon dioxide from the anode output product using the separation system. The method further includes supplying hydrogen to a combustion section of a gas turbine engine.

[0010] These and other features, aspects, and advantages of the present combustion system and method will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present technology and, together with the description, serve to explain the principles of the technology.

[0011] A full and enabling disclosure of the present combustion systems and methods, including the best mode of making and using the same, directed to those skilled in the art, is set forth in this specification, which makes reference to the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a combustion system according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of a combustion system according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of a combustion system according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of a combustion system according to an embodiment of the present disclosure. [Figure 5] FIG. 1 is a flow diagram of a method of operating a combustion system according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Reference will now be made in detail to embodiments of the present combustion systems and methods, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the present technology, not limitation thereof. Indeed, it will be apparent to those skilled in the art that modifications and variations can be made in the present technology without departing from the scope or spirit of the claimed technology. For example, features illustrated or described as part of one embodiment can be used on another embodiment to yield still further embodiments. Accordingly, the present disclosure is intended to cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0014] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Additionally, unless otherwise specified, all embodiments described herein should be considered exemplary.

[0015] In the detailed description, numerical and letter designations are used to refer to features in the drawings. Like or similar designations in the drawings and description are used to refer to like or similar parts of the invention. As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to denote the location or importance of individual components.

[0016] The term "fluid" can be a gas or a liquid. The term "fluid communication" means that a fluid can make a connection between designated areas.

[0017] As used herein, the terms "upstream" (or "forward") and "downstream" (or "aft") refer to relative directions with respect to fluid flow in a fluid pathway. For example, "upstream" refers to the direction from which fluid flows, and "downstream" refers to the direction from which fluid flows. However, as used herein, the terms "upstream" and "downstream" can also refer to electrical flow. The term "radially" refers to relative directions substantially perpendicular to the axial centerline of a particular component, the term "axially" refers to relative directions substantially parallel and / or coaxially aligned with the axial centerline of a particular component, and the term "circumferentially" refers to relative directions extending around the axial centerline of a particular component.

[0018] Approximate terms such as "about," "approximately," "approximately," and "substantially" are not intended to be limited to the exact value specified. In at least some cases, approximating language may correspond to the precision of an instrument for measuring a value or the precision of a method or machine for constructing or manufacturing a component and / or system. In at least some cases, approximating language may correspond to the precision of an instrument for measuring a value or the precision of a method or machine for constructing or manufacturing a component and / or system. For example, approximating language can refer to within a margin of 1, 2, 4, 5, 10, 15, or 20% for a particular value, a range of values, and / or any of the endpoints defining the range of values. When used in the context of an angle or direction, such terms include angles greater or less than 10 degrees above or less than the stated angle or direction. For example, "approximately perpendicular" includes directions within 10 degrees of perpendicular in any direction, e.g., clockwise or counterclockwise.

[0019] Terms such as "coupled," "fixed," and "attached," unless otherwise specified herein, refer to both direct coupling, fixing, or attachment, as well as indirect coupling, fixing, or attachment via one or more intermediate components or features. As used herein, the terms "comprises," "comprising," "includes," "including," "has," and "having," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or device that includes a list of features is not necessarily limited to only those features and may include other features not expressly listed or inherent in such process, method, article, or device. Further, unless expressly stated to the contrary, "or" refers to an inclusive "or" and not an exclusive "or." For example, condition A or B is satisfied by any one of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0020] Herein, throughout the specification and claims, range limitations are combinable and interchangeable, and unless the context and language dictate otherwise, such ranges are identified and include all subranges subsumed therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0021] As used herein, the term "line" can refer to a fluid-carrying conduit such as a pipe, hose, tube, or other fluid-carrying conduit.

[0022] Referring now to the drawings, FIGS. 1-4 each show a schematic diagram of an embodiment of a combustion system 100 (or combined cycle system, or system for producing blue hydrogen) including a topping cycle 102 and a bottoming cycle 104. In the topping cycle 102, fuel is combusted to generate electrical or mechanical power, resulting in exhaust gases 34. In the bottoming cycle 104, the exhaust gases 34 from the topping cycle 102 can then be used to generate additional electrical or mechanical power. In various embodiments, the topping cycle 102 may be an internal combustion engine, an industrial process in which fuel is combusted, or otherwise. In some embodiments, the bottoming cycle 104 may be a heat exchanger, boiler, economizer coil, supercritical carbon dioxide cycle, superheater, evaporator, pump, or the like. In an exemplary embodiment, the topping cycle 102 may be a gas turbine 10, and the bottoming cycle 104 may be a steam turbine system 22, as shown.

[0023] The combustion system 100 may include a gas turbine 10 for driving a first load 14. The first load 14 may be, for example, a generator for generating electrical power. The gas turbine 10 may include a turbine section 16, a combustor or combustion section 18, and a compressor section 20. The turbine section 16 and the compressor section 20 may be connected by one or more shafts 21.

[0024] In an exemplary embodiment, as described in more detail below, combustion system 100 may include a fuel cell 106 and a separation system 134. Fuel cell 106 may directly convert chemical energy stored in a hydrocarbon fuel into electrical energy through an electrochemical reaction while producing an output product. The output product from fuel cell 106 is sent to separation system 134, which may utilize the output product to produce a hydrogen stream (which may also be referred to as "blue hydrogen") via a water-gas shift (WGS) reactor 135. Hydrogen (H) from separation system 134 may be supplied to combustion section 18 to generate combustion gases.

[0025] In many embodiments, as shown, the combustion system 100 may include a hydrogen storage 179 that may store excess hydrogen produced by the fuel cell 106 and the water gas shift reactor 135. The hydrogen storage 179 may act as a buffer to bridge the dynamic mismatch between hydrogen production from the fuel cell 106 and hydrogen demand from the gas turbine 10. In some embodiments, additional hydrogen from the hydrogen storage 179 may be exported for other processes (e.g., the excess hydrogen may be sold). The hydrogen storage 179 may be a storage tank, a geological reservoir (such as a salt cavern), or a pipeline (such as for other industrial processes).

[0026] For example, during operation of the gas turbine 10, a working fluid such as air 25 (e.g., ambient or atmospheric air) enters the compressor section 20, where it is gradually compressed to provide compressed air to the combustors in the combustion section 18. The compressed air is mixed with fuel (e.g., hydrogen from the separation system 134) and burned in each combustor to generate combustion gases. The combustion gases enter the turbine section 16 from the combustion section 18 via a hot gas path, where energy (kinetic and / or thermal) is transferred from the combustion gases to rotor blades, causing one or more shafts 21 to rotate. This mechanical, rotational energy may then be used to power the compressor section 20 and / or generate electricity.

[0027] The heated exhaust gases 34 exiting the turbine section 16 then exit the gas turbine 10 and pass through a heat recovery steam generator (HRSG) 32 where heat is transferred between the exhaust gases 34 and various components of the HRSG 32 to generate steam for supplying the steam turbine system 22. The exhaust gases 34 exit the HRSG 32 and may be routed to the atmosphere via an exhaust stack 110.

[0028] The combustion system 100 may also include a steam turbine system 22 for driving a second load 24. The second load 24 may be a generator for generating electrical power. However, both the first load 14 and the second load 24 may be other types of loads that are driveable by the gas turbine 10 and the steam turbine system 22. Additionally, while the gas turbine 10 and the steam turbine system 22 may drive separate loads 14, 24 as shown in the illustrated embodiment, the gas turbine 10 and the steam turbine system 22 may also be utilized in tandem to drive a single load via a single shaft.

[0029] In the illustrated embodiment, the steam turbine system 22 may include a low-pressure (LP) steam turbine 26, an intermediate-pressure (IP) steam turbine 28, and a high-pressure (HP) steam turbine 30. The low-pressure (LP) steam turbine 26, the intermediate-pressure (IP) steam turbine 28, the high-pressure (HP) steam turbine 30, and the load 24 may each be disposed on one or more shafts 23 (such as a common shaft in some embodiments). In some embodiments (not shown), the outlet of the HP steam turbine 30 may be fluidly coupled to a reheater within the HRSG 32, where the steam is superheated and then supplied to the IP steam turbine 28 (or directly to the LP steam turbine 26 in embodiments where the IP steam turbine 28 is not present).

[0030] In an exemplary embodiment, the fuel cell 106 may include an anode side 112, a cathode side 116, and an electrolyte 114 (capable of conducting charged ions). The fuel cell 106 may directly convert chemical energy stored in a hydrocarbon fuel into electrical energy through an electrochemical reaction. In particular, the cathode side 116 may receive an oxidant (e.g., an oxidant flow) from a cathode inlet line 118. The anode side 112 may receive a fuel (e.g., methane or other hydrocarbon fuel) from an anode inlet line 126, which may be mixed with steam from a steam supply 186 (to maintain a desired steam-to-carbon ratio). The fuel on the anode side 112 and the oxidant on the cathode side 116 may electrochemically react with the electrolyte 114 within the fuel cell to produce a power output (e.g., a DC power output that may be supplied to a power converter 121), an anode output product, and a cathode output product. In an exemplary embodiment, the fuel cell 106 may be a molten carbonate fuel cell (MCFC), such as an internal reforming MCFC and / or an external reforming MCFC. In such an embodiment, the electrolyte 114 may be a molten carbonate mixture suspended in a porous, chemically inert ceramic matrix of beta-alumina solid electrolyte (BASE). The MCFC may operate by passing a reactive fuel gas (e.g., natural gas such as methane or other hydrocarbons) through the anode side 112 while passing an oxidizing gas through the cathode side 116, thereby causing an electrochemical reaction across the electrolyte 114 to produce electricity.

[0031] As briefly mentioned above, the fuel cell 106 converts the anode fuel stream into electrical energy while transferring oxygen and carbon dioxide from the exhaust gas as carbonate ions from the cathode side 116 to the anode side. For example, the fuel cell power output 120 may be directed to a power converter 121 to convert the DC current into AC current that can be effectively utilized by one or more subsystems. In particular, in the illustrated embodiment, the power output 120 is provided from the power converter to one or more electrical devices 122 via an electrical bus 124. The electrical bus 124 may be an electrical bus dedicated to the combustion system 100, the gas turbine 10, the steam turbine system 22, the fuel cell 106 electrical bus, or the like. The electrical bus 124 is in electrical communication with one or more additional electrical devices 122, which may be a current source, a current sink, or both. For example, the additional electrical device 122 may be an electrical storage device (e.g., one or more batteries), an electrical machine (a generator, an electric motor, or both), or both. Alternatively or additionally, the power output 120 may assist in driving the first load 14 and / or the second load 24. The combustion system 100 may generate a total power output (e.g., the sum of the power output 120 of the first load 14, the second load 24, and the fuel cell 106). In many embodiments, the power output 120 of the fuel cell 106 may be between about 10% and about 50% of the total power output of the combustion system 100. In other embodiments, the power output 120 of the fuel cell 106 may be between about 10% and about 30% of the total power output of the combustion system 100.

[0032] In many embodiments, the cathode side 116 may be fluidly coupled, at least in part, to one or more oxidant sources via a cathode inlet line 118. In particular, the cathode side 116 may receive oxidant from the cathode inlet line 118. For example, the cathode inlet line 118 may be fluidly coupled to one or more of an air separation unit (ASU) 154 and / or an air source 158. The cathode side 116 may be supplied with a mixture of O and CO. The liquid carbon dioxide separator 144 may supply CO to the cathode side 116, and the O source for the cathode side 116 may be the ASU 154 or ambient air. The cathode side 116 may be supplied with the required two moles of CO for every mole of O consumed in the cathode side 116. In the embodiment shown in FIG. 1, the cathode side 116 may be fluidly coupled to the air separation unit (ASU) 154. ASU 154 may separate air (such as atmospheric air in many embodiments) into its major components, typically nitrogen and oxygen, and sometimes argon and other noble inert gases. ASU 154 may supply a stream of oxygen (O) to cathode side 116 via cathode inlet line 118. For example, ASU 154 may supply a cathode inlet stream containing a large amount of oxygen (e.g., much higher than atmospheric air), such as greater than about 85% oxygen, or greater than about 90% oxygen, or greater than about 95% oxygen, or 100% oxygen. For example, cathode inlet line 118 may extend between ASU 154 and an inlet of cathode side 116.

[0033] In some embodiments, the oxygen storage 194 may be fluidly coupled to the ASU 154 and to the cathode inlet line 118. For example, the oxygen storage 194 may store oxygen from the ASU 154 (e.g., excess oxygen or oxygen generated when the system is not operating). The oxygen storage 194 may supply oxygen to the cathode side 116 via the cathode supply line 118 when the ASU 154 is down (e.g., not activated or non-operating) or during transient scenarios (e.g., when the ASU 154 is shut down and the air source 158 is turned on). Additionally, the oxygen storage 194 advantageously ensures that operational limitations of the ASU 154 do not limit the oxygen demand of the fuel cell 106. For example, if the fuel cell 106 requires more oxygen than the ASU 154 can produce, the oxygen storage 194 may supply the additional oxygen needed.

[0034] Additionally or alternatively, as shown in FIG. 2 , the cathode side 116 can be fluidly coupled to an air source 158 (such as atmospheric air or another air source) via an air inlet line 160. For example, the air inlet line 160 can extend between and fluidly couple the air source 158 and the cathode inlet line 118. The air source 158 can provide atmospheric air (e.g., air containing about 78% nitrogen, about 21% oxygen, about 1% argon, and about 0.05% carbon dioxide). In some embodiments, the air source 158 can be a storage tank having atmospheric air contained therein. In other embodiments, the air source 158 can be a fan or blower fluidly coupled to atmospheric air and the cathode inlet line 118, where operation of the fan or blower supplies atmospheric air to the cathode side 116. In yet other embodiments (not shown), oxygen can be provided or generated from an associated electrolyzer. In such an embodiment, the products of the parallel electrolyzer are H2 and O2, and O2 may be fed to the cathode side 116.

[0035] 1 and 2, the combustion system 100 may include a backup fuel supply 190 fluidly coupled to the combustor fuel supply line 178. The backup fuel supply 190 may supply fuel to the gas turbine 10 when the fuel cell 106 is not operating or in a part load scenario.

[0036] In an alternative embodiment, as shown in FIG. 3 , the cathode side 116 may be fluidly coupled to the outlet of the turbine section 16. For example, a branch line 162 may extend from the turbine outlet line 152. The branch line 162 may carry a portion of the exhaust gas to the cathode inlet line 118, where the exhaust gas travels to the inlet of the cathode side 116. The exhaust gas may include nitrogen, carbon dioxide, oxygen, and water. In some embodiments, all of the exhaust gas 34 from the outlet of the turbine section 16 may be routed through the cathode side 116 of the fuel cell 106, thereby removing a portion of the CO2 from the exhaust gas. For example, a fuel cell (which is an MCFC in an exemplary embodiment) may operate by passing a reactive fuel gas (e.g., natural gas) through the anode side 112 while passing an oxidizing gas (e.g., exhaust gas containing carbon dioxide) through the cathode side 116, whereby an electrochemical reaction occurs across the electrolyte 114, consuming (or chemically converting) carbon dioxide to produce electricity. In particular, up to approximately 85% of the carbon dioxide in the exhaust gas from turbine section 16 may be removed (i.e., electrochemically converted) on cathode side 116 of fuel cell 106. In such an embodiment, combustor fuel supply 15 may supply fuel to the combustor of combustion section 18 in addition to, or as an alternative to, the fuel supplied by separation system 134. Combustor fuel supply 15 may supply natural gas, such as a hydrocarbon fuel, which may include methane, propane, etc., to combustion section 18. In an exemplary embodiment, combustor fuel supply 15 may supply methane (CH4) to combustion section 18.

[0037] In various embodiments, the anode side 112 may receive a flow of fuel and steam (e.g., a fuel / steam mixture) via an anode inlet line 126. The fuel may be conveyed through the anode side 112. The anode inlet line 126 may fluidly couple the anode side 112 to an anode fuel supply 128. The amount of fuel supplied to the anode side 112 may be the sum of the fuel needed to operate the fuel cell 106 and the fuel needed to generate the hydrogen demand by a process (e.g., the topping cycle 102 or other industrial process using hydrogen) via in-situ steam methane reforming. In some embodiments, the anode fuel supply 128 may be the same as the combustor fuel supply 15, and the same fuel is supplied to both the combustion section and the anode side of the fuel cell 106. In an exemplary embodiment, the amount of fuel supplied to the fuel cell 106 may be the sum of the fuel demand of the fuel cell 106 and the hydrogen demand of the gas turbine 10. In other embodiments, the anode fuel supply 128 and the combustor fuel supply 15 may be different. In many implementations, the anode fuel supply 128 may supply natural gas (e.g., a hydrocarbon fuel) to the anode side 112 via the anode inlet line 126. The natural gas may include methane, propane, or the like. In an exemplary embodiment, the anode fuel supply 128 may supply methane (CH4) to the anode side 112. In some embodiments (not shown), a fuel preheater, such as a heat exchanger, may be disposed in thermal communication on the anode inlet line 126 to heat the fuel before it enters the anode side 112.

[0038] In the exemplary embodiment, the combustion system 100 may include an anode steam supply 186 fluidly coupled to the anode inlet line 126 via an anode steam supply line 188. The anode steam supply line 188 may extend between and fluidly couple the anode steam supply 186 and the anode inlet line 126. The anode steam supply line 188 may provide a flow of steam to the anode inlet line 126 for use in the anode side 112 of the fuel cell 106. In various embodiments (not shown), the anode steam supply 186 may be fluidly coupled to the HRSG 32, which provides steam to both the steam turbine system 22 and the anode side 112 of the fuel cell 106. The anode steam may be generated by utilizing heat from the heat exchanger 136 and may be augmented by providing steam from the HRSG 32. In some embodiments, a fuel inlet heater may be located in the anode inlet line 126 upstream of the anode inlet to heat the fuel / steam entering the anode side 112.

[0039] In many embodiments, the combustion system 100 may include an anode outlet line 132 fluidly coupled to the outlet of the anode side 112 to receive output products from the anode side 112 after the electrochemical reaction in the fuel cell 106. In certain embodiments, the anode output products may include CO, CO, H (e.g., "blue hydrogen"), water, and unused CH (e.g., methane not utilized in the fuel cell 106 during the electrochemical reaction). The anode output products may be supplied to a separation system 134, which chemically converts carbon monoxide and water to carbon dioxide and hydrogen, after which the water and liquefied CO can be removed.

[0040] The separation system 134 may include, in serial flow order (e.g., from upstream to downstream), a heat exchanger 136, a water-gas shift reactor 135, a water flash separator 138, a compressor 140, a chiller 142, and a liquid carbon dioxide separator 144. The heat exchanger 136 may be thermally and fluidly coupled to the anode outlet line 132. For example, the anode outlet line 132 may extend between an outlet of the anode side 112 and the heat exchanger 136. The heat exchanger 136 may remove or add heat to the anode output product before entering the water flash separator 138. The water-gas shift inlet line 133 may extend between and fluidly couple the heat exchanger 136 and the water-gas shift reactor 135.

[0041] The water-gas shift reactor 135 may produce hydrogen from the anode output product, and the combustion section 18 of the gas turbine 10 may be fluidly coupled to the separation system 134 such that the combustion section 18 receives the hydrogen produced from the anode output product. In particular, the water-gas shift reactor may convert carbon monoxide (CO) and water (HO) in the anode output product to carbon dioxide (CO) and hydrogen (H). Thus, the WGS output products may include CO, H, HO, unutilized CO, and unutilized CH. For example, “unutilized CH” may be methane not consumed in the fuel cell 106, and similarly, “unutilized CO” may be carbon monoxide not consumed in the water-gas shift reactor 135.

[0042] In some embodiments, as shown in FIG. 3, a hydrogen separator 192 may be included in the separation system 134. The hydrogen separator may be a membrane system or a pressure swing adsorption (PSA) system. The hydrogen separator 192 may separate hydrogen from the hydrogen-rich stream after the water flash separator 144. The hydrogen separator 134 may be included in combustion systems requiring very high purity H, which advantageously facilitates approximately 100% carbon dioxide capture and / or negative emissions (e.g., greater than 100% carbon dioxide capture in some operating implementations). The anode output products (unconverted CO and unconverted CH and CO) separated from the hydrogen separator may be recycled to the anode inlet (e.g., via the anode recycle line 145). In embodiments having a hydrogen separator 192, a water gas shift reactor may be optional (e.g., not included).

[0043] A water flash inlet line 137 may extend between and fluidly couple the water gas shift reactor 135 and the water flash separator 138. The water flash separator 138 may remove any water from the WGS output product. For example, the water in the WGS output product may be cooled to a liquefaction temperature that is removed by the water flash separator 138. For example, the water flash separator 138 may include a water outlet line 182 extending from the water flash separator 138 and carrying any water removed from the WGS output product by the water flash separator 138.

[0044] In many embodiments, compressor inlet line 139 may extend between and fluidly couple water flash separator 138 and compressor 140. Compressor 140 may compress the WGS output product and provide the compressed WGS output product to chiller 142 via chiller inlet line 141. Chiller 142 may liquefy CO2 in the compressed WGS output product by reducing the temperature of the compressed WGS output product. The liquid CO2 may then be removed via liquid carbon dioxide separator 144. For example, chiller 142 may be fluidly coupled to liquid carbon dioxide separator 144 via connecting line 143.

[0045] The liquid carbon dioxide separator 144 may include a liquid carbon dioxide outlet line 172 that may be partially in fluid communication with the cathode inlet line 118 (e.g., a portion of the liquid carbon dioxide may be supplied to the cathode inlet line 118). The liquid carbon dioxide outlet line 172 may extend from the liquid carbon dioxide separator 144. A branch line 174 may extend between and fluidly couple the liquid carbon dioxide outlet line 172 and the cathode inlet line 118, such that the liquid carbon dioxide separated from the WGS output product is supplied to the cathode side 116 for subsequent electrochemical conversion (e.g., the CO may be converted within the fuel cell 106). In particular, the liquid CO may be reheated in a cathode input heat exchanger 176. The cathode input heat exchanger 176 may heat the oxidant (e.g., oxygen, atmospheric air, and / or exhaust gas) and / or the liquid CO (thereby vaporizing the liquid CO into gaseous CO before entering the cathode side 116).

[0046] A primary combustor fuel supply line 178 may extend from the outlet of the separation system 134 and the combustion section of the gas turbine to supply the output product from the separation system 134 to a combustor in the combustion section 18 of the gas turbine 10. In particular, the primary combustor fuel supply line 178 may extend from the liquid carbon dioxide separator 144 to the combustion section 18. The primary combustor fuel supply line 178 may supply a fuel stream containing primarily hydrogen (e.g., greater than 50% hydrogen) to the combustion section 18. More specifically, the primary combustor fuel supply line may supply a fuel stream containing about 85% to about 99% hydrogen, about 1% to about 5% methane, and carbon monoxide. In an exemplary embodiment, the combustion section 18 may receive fuel only from the output product of the separation system 134, without requiring a dedicated fuel supply.

[0047] In some embodiments, as shown in FIGS. 1-4 , the anode recirculation line 145 may extend from the separation system 134 to the anode inlet line 126. In particular, the anode recirculation line 145 may extend from the outlet of the separation system 134 to the anode inlet line 126. For example, the anode recirculation line 145 may extend from the primary combustor fuel supply line 178 to the anode inlet line 126 to reintroduce a portion of the anode output product (from which water and liquid carbon dioxide have been removed) to the anode side 112. For example, the anode recirculation line 145 may advantageously reintroduce any unconverted methane and / or any unconverted carbon monoxide to the anode side 112 for electrochemical conversion. The anode recirculation line 145 may facilitate load sharing between the fuel cell 106 and the gas turbine 10. This also facilitates system startup and other transient events in which the anode output product has low hydrogen purity. In this case, the storage tank 179 supplies fuel to the gas turbine 179 and the anode output product is recycled to the anode inlet to stabilize the process.

[0048] The HRSG 32 may generate steam from the heat of the exhaust gases exiting the turbine section 16 and may supply the steam to the steam turbine system 22. For example, a steam supply line 148 may extend from the HRSG 32 to the steam turbine system 22. In particular, the steam supply line 148 may extend from the HRSG 32 to the HP steam turbine 30. An outlet of the HP steam turbine 30 may be fluidly coupled to an inlet of the IP steam turbine 28 (or an HRSG reheater), and an outlet of the IP steam turbine 28 may be fluidly coupled to an inlet of the LP steam turbine 26. An outlet of the LP steam turbine may be fluidly coupled to a condenser 150 via a turbine outlet line 152. The condenser may convert steam from the outlet of the LP steam turbine 26 into water, and the water may be returned to the HRSG 32 via a condensate return line 151.

[0049] In many embodiments, the combustion system 100 may further include a cathode outlet line 168 that carries the cathode output product from the cathode side 116. In some embodiments, as shown in FIG. 1 , the cathode outlet line 168 may extend from the outlet of the cathode side 116 to the cathode inlet line 118, fluidly connecting them. In such embodiments, the cathode output product may be recycled to the inlet of the cathode side 116 for further electrochemical conversion. Thus, unreacted CO and O are recycled back to the fuel cell 106. In other words, because CO is not released from the cycle, the fuel cell 106 may achieve a carbon capture rate near 100%. A blowdown line 169 may be fluidly connected to the ambient environment and the cathode outlet line 168 for disposal of at least a portion of the cathode output product (e.g., unreacted species in the cathode output product may be disposed of, such as argon and nitrogen). The blowdown line 169 may prevent the accumulation of small amounts of non-reactive species in the system, such as argon, nitrogen, or impurities introduced by the ASU 154.

[0050] 2 and 3, the cathode outlet line 168 may extend between the cathode side 116 and the air preheater 180. The air preheater 180 may be disposed on and in thermal communication with the air inlet line 160. For example, the air preheater 180 may be a heat exchanger that transfers heat between the cathode output product in the cathode outlet line 168 and the air in the air inlet line 160. In some embodiments (not shown), the cathode output product may then be fed to the cathode inlet line 118 for recirculation through the cathode side 116 after passing through the air preheater 180.

[0051] In various implementations, the combustion system 100 may include three operating modes: a first operating mode, a second operating mode, and a third operating mode, for example.

[0052] In a first mode of operation, the anode side 112 can receive methane fuel from the anode fuel supply 128, and the cathode side 116 can receive oxygen from the ASU 154 and a portion of the liquid carbon dioxide from the carbon dioxide separator 144. The fuel cell 106 can produce a power output 120, a cathode output product, and an anode output product. In the first mode of operation, the cathode output product can be recycled to the cathode inlet line 118, as shown in FIG. 1 . The anode output product, including hydrogen, can be supplied to the separation system 134. The water-gas shift reactor 135 can receive the anode output product and produce additional hydrogen. Water and carbon dioxide can then be removed from the anode output product, leaving hydrogen, unconverted methane, and unconverted carbon monoxide, which can be conveyed to the combustion section for combustion via the primary combustor fuel supply line 178. In such an embodiment, the combustors of the combustion section 18 may operate solely on fuel supplied by the fuel cell 106 and the separation system 134, and no other dedicated fuel supply is required for the combustion section 18.

[0053] In a second operating mode, the anode side 112 can receive methane fuel from the anode fuel supply 128, and the cathode side 116 can receive atmospheric air from the air source and a portion of the liquid carbon dioxide from the carbon dioxide separator 144. The fuel cell 106 can produce a power output 120, a cathode output product, and an anode output product. In the second operating mode, as shown in FIG. 2 , the cathode output product can be supplied to an air preheater 180 located on the air inlet line 160 to heat the atmospheric air supplied to the cathode side 116. The anode output product, including hydrogen, can be supplied to the separation system 134. The water-gas shift reactor 135 can receive the anode output product and produce additional hydrogen. Water and carbon dioxide can then be removed from the anode output product, leaving hydrogen, unconverted methane, and unconverted carbon monoxide, which can be conveyed to the combustion section for combustion via the primary combustor fuel supply line 178. In such an embodiment, the combustors of the combustion section 18 may operate solely on fuel supplied by the fuel cell 106 and the separation system 134, and no other dedicated fuel supply is required for the combustion section 18.

[0054] In a third operating mode, the anode side 112 can receive methane fuel from the anode fuel supply 128, and the cathode side 116 can receive exhaust gas from the turbine section 16 of the gas turbine 10. The fuel cell 106 can produce an electrical power output 120, a cathode output product, and an anode output product. Additionally, the fuel cell 106 can convert carbon dioxide from the exhaust gas. The anode output product, including hydrogen, can be supplied to a separation system 134. A water-gas shift reactor 135 can receive the anode output product and produce additional hydrogen. Water and carbon dioxide can then be removed from the anode output product, leaving hydrogen, unconverted methane, and unconverted carbon monoxide, which can be conveyed to the combustion section 18 for combustion via a primary combustor fuel supply line 178. In the third operating mode, the combustor in the combustion section 18 can receive methane from the combustor fuel supply 15 in addition to, or as an alternative to, the fuel from the separation system 134. In many embodiments, system 100 may switch between the second and third modes of operation when ASU 154 is unavailable (or inoperative).

[0055] Referring now to FIG. 4 , in some embodiments, the combustion system 100 may include a Graz cycle 200 having a topping cycle 202 and a bottoming cycle 204. In the topping cycle 202, fuel is combusted to generate electrical or mechanical power. In the bottoming cycle 204, output products from the topping cycle 202 may be used to generate additional electrical power. In various embodiments, the topping cycle 202 may be an internal combustion engine, an industrial process in which fuel is combusted, or the like. In some embodiments, the bottoming cycle 204 may be a heat exchanger, a boiler, an economizer coil, a supercritical carbon dioxide cycle, a superheater, an evaporator, a pump, or the like. The topping cycle 202 may be coupled to a first load 14, and the bottoming cycle 204 may be coupled to a second load 24.

[0056] In the exemplary embodiment, the topping cycle 202 may be a gas turbine 10 that does not include a compressor section. For example, the ASU 154 may be overdesigned to meet the demands of the fuel cell 106 and the gas turbine 10. In particular, the gas turbine 10 may operate in an oxy-combustion mode in which hydrogen is supplied to the combustion section 18 and additional oxygen from the ASU 154 is supplied to the gas turbine 10. The oxygen supply line 196 may extend directly between the ASU 154 and the combustion section 18. In some implementations, steam, nitrogen (N), or other inert gases such as argon (Ar) may be used as a dilution gas to maintain a desired oxygen concentration at the combustor inlet.

[0057] Supplying only hydrogen and oxygen to the gas turbine removes nitrogen from the output product of the gas turbine 10, resulting in only a small amount of oxygen being present in the output product of the gas turbine 10. In other words, if the gas turbine 10 is supplied with oxygen from the ASU 154, the exhaust of the gas turbine may be primarily water. The water may be supplied to the heat exchanger 208 via a heat exchanger inlet line 210 and subsequently to one or more additional systems 206. The additional systems 206 may include a steam turbine, a recirculation line, and / or an exhaust line. The heat exchanger 208 may generate steam for use in the bottoming cycle 204. For example, steam from the heat exchanger 208 may be supplied to the bottoming cycle 204 via a bottoming cycle inlet line 212 extending between the heat exchanger and the bottoming cycle 204. The condenser 150 may be fluidly coupled to the outlet of the bottoming cycle 204, and the condensate may be supplied to the heat exchanger 208 via a heat exchanger return line 214 extending between the condenser 150 and the heat exchanger 208.

[0058] Referring now to FIG. 5 , a flow diagram of one embodiment of a method 400 for operating a combustion system 100 in accordance with an aspect of the present subject matter is shown. Generally, the method 400 is described herein with reference to the combustion system 100 described above with reference to FIGS. 1-4 . However, those skilled in the art will understand that the disclosed method 400 may generally be utilized with any suitable combustion system and / or in connection with a system having any other suitable system configuration. Additionally, while FIG. 5 depicts steps performed in a particular order for purposes of illustration and description, the methods described herein are not limited to any particular order or arrangement unless otherwise specified in the claims. Using the disclosure provided herein, those skilled in the art will understand that various steps of the methods disclosed herein can be omitted, rearranged, combined, and / or adapted in various ways without departing from the scope of the present disclosure. As shown, dashed boxes in FIG. 5 may indicate optional steps of the method 400.

[0059] As shown, the method 400 may include supplying fuel to the anode side 112 of the fuel cell 106 using the anode inlet line 126 at 402. For example, supplying the fuel to the anode side 112 of the fuel cell 106 may include conveying fuel from an anode fuel supply 128 to an inlet of the anode side 112. In many embodiments, as shown, supplying at 402 may further include supplying methane (CH4) to the anode side 112 of the fuel cell 106 at 404. Methane may advantageously produce the most desirable output product from the fuel cell 106 while maintaining efficient operation of the fuel cell 106, which may be further processed and used in the gas turbine 10. In many embodiments, the method 400 may include supplying steam from the anode steam supply 186 to the anode side 112 along with the fuel, at least in part via the steam supply line 188. For example, a steam supply line 188 may introduce a flow of steam into the anode inlet line 126 upstream of the anode side 112, and a mixture of fuel and steam may be supplied to the anode side 112 to power the electrochemical reaction in the fuel cell 106. In some embodiments (not shown), the steam may be supplied from the HRSG 32. The steam and methane power a steam-methane reforming reaction that occurs inside the anode side 112, which produces most of the hydrogen needed for the electrochemical reaction in the fuel cell 106 and most of the hydrogen needs of the gas turbine 10. Unconverted carbon monoxide reacts with water in the water-gas shift reactor 135 to produce some additional hydrogen, such that most of the carbon monoxide is utilized.

[0060] 5 , the method 400 may further include supplying (406) an oxidant to the cathode side 116 of the fuel cell 106 using the cathode inlet line 118. For example, in some embodiments, supplying the oxidant at (406) may include supplying (408) oxygen from the air separation unit 154 to the cathode side 116 of the fuel cell using the cathode inlet line 118. For example, the ASU 154 may supply a cathode inlet stream containing a large amount of oxygen (e.g., much higher than atmospheric air), such as greater than about 85% oxygen, or greater than about 90% oxygen, or greater than about 95% oxygen, or about 100% oxygen. In other embodiments, the oxygen may be supplied or generated from an attached electrolyzer. In such embodiments, the products of the attached electrolyzer are H and O, and the O may be supplied to the cathode side 116.

[0061] Additionally or alternatively, supplying the oxidant at (406) may further include supplying atmospheric air to the cathode side 116 of the fuel cell 106 at (410), at least in part, using the cathode inlet line 118. For example, in implementations, the oxidant supplied to the cathode side 116 may be solely atmospheric air (e.g., 100%). In other implementations, the oxidant supplied to the cathode side 116 may be a mixture of atmospheric air and oxygen from the ASU 154. In still further embodiments, supplying the oxidant at (406) may further include supplying exhaust gas from the turbine section 16 of the gas turbine 10 to the cathode side 116 of the fuel cell 106 at (412), at least in part, using the cathode inlet line 118. For example, in some implementations, the oxidant supplied to the cathode side 116 may be solely exhaust gas (e.g., 100%). In other embodiments, the oxidant supplied to the cathode side 116 may be a mixture of exhaust gas, oxygen from the ASU 154, and / or atmospheric air.

[0062] The oxidant supplied to the cathode side 116 and the fuel supplied to the anode side 112 may travel through the fuel cell 106 on either side of the electrolyte 114. During this process, electrochemical reactions may occur across the electrolyte 114 to produce electrical power output 120, anode output products, and cathode output products. The anode output products may include CO, CO, H, water, and unused CH (e.g., methane not utilized in the fuel cell 106 during the electrochemical reaction).

[0063] The method 400 may include, at 413, producing an anode output product containing a first portion of hydrogen using the fuel cell 106. For example, hydrogen (which may be referred to as "blue hydrogen") may be produced as a result of an electrochemical reaction in the fuel cell 106.

[0064] In an example implementation, the method 400 may include, at 414, providing the anode output product from the anode side 112 to a separation system 134. The separation system 134 may include a water-gas-shift reactor 135, a water flash separator 138, and a liquid carbon dioxide separator 144. In many implementations, the method 400 may include, at 416, producing a second portion of hydrogen (H) from the anode output product using the water-gas-shift reactor 135. For example, the second portion of hydrogen may be produced as a result of a reaction in the water-gas-shift reactor 135. For example, the water-gas-shift reactor 135 may convert carbon monoxide and water vapor in the anode output product to carbon dioxide and hydrogen. The output products from the water-gas-shift reactor 135 may include CO, H, HO, unused CO, and unused CH. The second portion of hydrogen may be less than the first portion of hydrogen. That is, a majority of the hydrogen may be produced in the fuel cell 106, and the remainder may be produced in the water gas shift reactor 135. In many implementations, the first portion of the hydrogen produced by the fuel cell 106 may be between about 60% and about 95% of the total hydrogen produced in the combustion system 100, and the remaining hydrogen may be produced by the water gas shift reactor 135.

[0065] In many implementations, the anode output product may first be fed to a heat exchanger 136 for heat transfer before entering the water gas shift reactor 135. The heat exchanger may remove heat (or in some embodiments, add heat) from the anode output product to promote efficient reaction within the water gas shift reactor 135. In particular, the heat exchanger 136 may recover heat from the outlet of the fuel cell 106, which is approximately 650°C, and use that heat to generate steam to feed the cathode inlet stream.

[0066] The method 400 may further include removing water and carbon dioxide from the anode output product using the separation system 134 at 418. In particular, the water and carbon dioxide may be removed after the water-gas shift reaction, whereby the water and carbon dioxide are removed from the output product of the water-gas shift reactor 135. In particular, the removing at 418 may further include removing water from the anode output product using the water flash separator 138. The water flash separator may be a gas-liquid separator or another type of separator. Additionally, the method 400 may include compressing the anode output product with the compressor 140. For example, upon exiting the water flash separator 138, the anode output product may be fed to the compressor, thereby pressurizing the anode output product. In such an embodiment, the method 400 may include cooling the anode output product with the chiller 142. As a result, the gaseous carbon dioxide in the anode output product is condensed into liquid carbon dioxide. In particular, the pressurized anode output product may be supplied to a chiller 142 after exiting the compressor 140, which may reduce the temperature of the anode output product to condense the carbon dioxide. The method 400 may then include removing liquid carbon dioxide from the anode output product using a liquid carbon dioxide separator 144.

[0067] The liquid carbon dioxide separator 144 may remove any liquid carbon dioxide from the anode output product and convey the liquid carbon dioxide using the liquid carbon dioxide outlet line 172. In many embodiments, the method 400 may further include supplying the liquid carbon dioxide to the cathode inlet line 118. For example, the liquid carbon dioxide outlet line 172 may be fluidly coupled to the cathode inlet line 118 via a branch line 174. The liquid CO may be reheated (and revaporized) in the cathode input heat exchanger 176. The cathode input heat exchanger 176 may heat the oxidant (e.g., oxygen, atmospheric air, and / or exhaust gas) and / or the liquid CO in the cathode inlet line 118 (thereby vaporizing the liquid CO into gaseous CO before entering the cathode side 116). Additionally, the cathode input heat exchanger 176 may maintain the temperature of the cathode input products (eg, oxygen and / or ambient air) between about 500°C and about 650°C, or between about 600°C and about 650°C, etc.

[0068] In an example implementation, the method 400 may include, at 420, supplying hydrogen to the combustion section 18 of the gas turbine 10. For example, this may include supplying a first portion of the hydrogen produced by the fuel cell 106 and a second portion of the hydrogen produced by the water gas shift reactor 134 to the combustion section 18 of the gas turbine 10. In particular, a primary combustor fuel supply line 178 may extend from the liquid carbon dioxide separator 144 to the combustion section 18 to supply an output product from the separation system 134 (e.g., an anode output product reformed by the separation system 134). The primary combustor fuel supply line 178 may supply a fuel stream containing primarily hydrogen (e.g., greater than 50% hydrogen) to the combustion section 18. More specifically, the primary combustor fuel supply line may supply a fuel stream containing about 85% to about 95% hydrogen, about 1% to about 5% methane, and carbon monoxide to the combustion section 18. The method 400 may include operating a combustor of the combustion section (e.g., igniting one or more fuel nozzles) with fuel supplied from the separation system 134 via the primary combustor fuel supply line 178.

[0069] In an exemplary embodiment, fuel cell 106 (via water gas shift reactor 135) and separation system 134 can produce (or generate) a stream of blue hydrogen, which can be purified into a nearly pure (e.g., about 100%) hydrogen stream via hydrogen separator 192. In an exemplary embodiment, as shown in FIGS. 1-3 , this blue hydrogen can be supplied to a combustion system (such as to combustion section 18 via combustor fuel supply line 178) or stored in hydrogen storage 179. However, in other embodiments, the blue hydrogen can be used for other industrial applications.

[0070] 1, the method may include supplying a cathode output product from the cathode side to the cathode inlet line 118 using a cathode outlet line 168. In such embodiments, the cathode output product may be recycled to the inlet of the cathode side 116 for further electrochemical conversion.

[0071] In other embodiments, as shown in FIG. 2 , the method may include supplying the cathode output product from the cathode side 116 to an air preheater 180 using the cathode outlet line 168. The air preheater 180 may be disposed on the air inlet line 160. Alternatively, as shown by the dashed line in FIG. 2 , the air preheater 180 may be disposed on the cathode inlet line 118 immediately upstream of the cathode input heat exchanger 176. In such embodiments, the cathode output product may heat the oxidant from the ASU 154 and / or the carbon dioxide from the carbon dioxide separator 144. The cathode output product may be supplied to the air preheater 180 disposed on the air inlet line 160 to heat the atmospheric air supplied to the cathode side 116.

[0072] This specification uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and practicing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that have no substantial differences from the literal language of the claims.

[0073] Further aspects of the invention are provided by the subject matter of the following clauses.

[0074] 1. A combustion system comprising: a topping cycle; a fuel cell including an anode side, a cathode side, and an electrolyte, the anode side receiving fuel via an anode inlet line and producing an anode output product containing a first portion of hydrogen, and the cathode side receiving an oxidant from the cathode inlet line; and a separation system having a water gas shift reactor producing a second portion of hydrogen from the anode output product, the topping cycle being fluidly coupled to the separation system such that the topping cycle receives the hydrogen produced from the anode output product.

[0075] The combustion system of the preceding clause, wherein the cathode side receives oxidant from a cathode inlet line, the cathode inlet line being fluidly coupled to one or more of an air separation unit (ASU) or an air source.

[0076] The combustion system of any preceding clause, wherein the cathode outlet line extends from the cathode outlet to the cathode inlet line.

[0077] The combustion system of any preceding clause, wherein the cathode inlet line is fluidly coupled to the air source via an air inlet line.

[0078] The combustion system of any of the preceding clauses, wherein the cathode outlet line extends between the cathode side and the air preheater, the air preheater being disposed on and in thermal communication with the air inlet line.

[0079] The combustion system of any preceding clause, wherein the anode recirculation line extends from the separation system to the anode inlet line.

[0080] 10. The combustion system of claim 1, wherein the separation system includes a water flash separator having a water outlet line and a liquid carbon dioxide separator having a liquid carbon dioxide outlet line, and the branch line fluidly couples the cathode inlet line to the liquid carbon dioxide outlet line of the liquid carbon dioxide separator.

[0081] 10. The combustion system of any preceding clause, further comprising an anode steam supply fluidly coupled to the anode inlet line via an anode steam supply line.

[0082] The combustion system of any of the preceding clauses, wherein the topping cycle is a gas turbine having a compressor section, a combustion section, and a turbine section, the combustion section further comprising a heat recovery steam generator (HRSG) that receives exhaust gas from the turbine section via a turbine outlet line, the HRSG generating steam for use in the bottoming cycle.

[0083] The combustion system of any preceding clause, wherein the separation system further comprises a hydrogen separator.

[0084] 1. A method of operating a combustion system, the combustion system having a fuel cell with an anode side, a cathode side, and an electrolyte, the method including: supplying fuel to the anode side of the fuel cell using an anode inlet line; supplying oxidant to the cathode side of the fuel cell using a cathode inlet line; producing an anode output product containing a first portion of hydrogen using the fuel cell; supplying the anode output product from the anode side to a separation system, the separation system including a water gas shift reactor; producing a second portion of hydrogen from the anode output product using the water gas shift reactor; removing water and carbon dioxide from the anode output product using the separation system; and supplying the hydrogen to a combustion section of a gas turbine engine.

[0085] The method of any preceding clause, wherein supplying oxidant further comprises supplying oxygen from an air separation unit to the cathode side of the fuel cell using a cathode inlet line.

[0086] The method of any of the preceding clauses, wherein supplying the oxidant further comprises supplying atmospheric air to the cathode side of the fuel cell, at least in part using the cathode inlet line.

[0087] The method of any of the preceding clauses, wherein supplying the oxidant further comprises supplying exhaust gas from a turbine section of the gas turbine to the cathode side of the fuel cell at least in part using a cathode inlet line.

[0088] The method of any of the preceding clauses, wherein supplying the fuel to the anode side further comprises supplying methane to the anode side of the fuel cell.

[0089] 10. The method of any of the preceding clauses, wherein the removing step further comprises removing water from the anode output product using a water flash separator; compressing the anode output product with a compressor; and cooling the anode output product with a chiller, whereby gaseous carbon dioxide in the anode output product is condensed into liquid carbon dioxide; and removing liquid carbon dioxide from the anode output product using a liquid carbon dioxide separator.

[0090] The method of any of the preceding clauses, further comprising supplying liquid carbon dioxide to a cathode inlet line, the cathode inlet line fluidly coupled to a cathode side of the fuel cell.

[0091] 10. The method of any of the preceding clauses, further comprising: using a cathode outlet line to supply cathode output products from the cathode side to an air preheater, the air preheater being disposed on the air inlet line.

[0092] The method of any of the preceding clauses, further comprising using a cathode outlet line to supply a cathode output product from the cathode side to the cathode inlet line.

[0093] 1. A blue hydrogen generation system comprising: a fuel cell including an anode side, a cathode side, and an electrolyte, wherein the anode side receives fuel via an anode inlet line and produces an anode output product containing a first portion of hydrogen, the cathode side receives an oxidant from the cathode inlet line, and the anode side receives fuel from an anode fuel supply; and a separation system having a water gas shift reactor that produces a second portion of hydrogen from the anode output product.

[0094] The blue hydrogen generation system of the preceding clause, wherein the cathode side receives an oxidant from the cathode inlet line, and the cathode inlet line is fluidly coupled to one or more of an air separation unit (ASU) or an air source.

[0095] 4. The blue hydrogen generation system of any of the preceding clauses, wherein the cathode outlet line extends from the cathode side outlet to the cathode inlet line.

[0096] 10. The blue hydrogen generation system of any of the preceding clauses, wherein the cathode inlet line is fluidly coupled to an air source via an air inlet line.

[0097] 10. The blue hydrogen generation system of claim 1, wherein the cathode outlet line extends between the cathode side and the air preheater, and the air preheater is disposed on and in thermal communication with the air inlet line.

[0098] 4. The blue hydrogen production system of any preceding clause, wherein the anode recirculation line extends from the separation system to the anode inlet line.

[0099] 10. The blue hydrogen production system of claim 1, wherein the separation system comprises a water flash separator having a water outlet line and a liquid carbon dioxide separator having a liquid carbon dioxide outlet line, and the branch line fluidly couples the cathode inlet line to the liquid carbon dioxide outlet line of the liquid carbon dioxide separator.

[0100] 10. The blue hydrogen generation system of any preceding clause, further comprising an anode vapor supply fluidly coupled to the anode inlet line via an anode vapor supply line.

[0101] The blue hydrogen generation system of any of the preceding clauses, wherein the separation system further comprises a hydrogen separator. [Explanation of symbols]

[0102] 10. Gas turbine 14 First Load 15 Combustor fuel supply section 16 Turbine Section 18 Combustion Section 20 Compressor Section 21 Shaft 22 Steam Turbine System 23 Shaft 24 Second Load 25 Air 26 Low-pressure steam turbine 28 Intermediate-pressure steam turbine 30 High-pressure steam turbine 32 Heat recovery steam generator (HRSG) 34 Exhaust gas 100 Combustion System 102 Topping Cycle 104 Bottoming Cycle 106 Fuel Cell 110 Exhaust stack 112 Anode side 114 Electrolytes 116 Cathode side 118 Cathode inlet line 120 Power Output 121 Power Converter 122 Electrical Equipment 124 Electric Bus 126 Anode inlet line 128 Anode fuel supply unit 132 Anode outlet line 133 Water-gas shift inlet line 134 Separation System 135 Water Gas Shift Reactor 136 Heat exchanger 137 Water flush inlet line 138 Water Flash Separator 139 Compressor inlet line 140 Compressor 141 Chiller inlet line 142 Chiller 143 Connection Line 144 Liquid carbon dioxide separator 145 Anode recirculation line 148 Steam Supply Line 150 Condenser 151 Condensate return line 152 Turbine outlet line 154 Air Separation Unit (ASU) 158 Air Source 160 Air Inlet Line 162 Branch Line 168 Cathode outlet line 169 Blowdown Line 172 Liquid carbon dioxide outlet line 174 Branch Line 176 Cathode input heat exchanger 178 Combustion fuel supply line 179 Hydrogen storage unit 180 Air preheater 182 Water Outlet Line 186 Anode vapor supply section 188 Anode vapor supply line 190 Backup fuel supply unit 192 Hydrogen Separator 194 Oxygen storage unit 196 Oxygen supply line 200 Graz Cycle 202 Topping Cycle 204 Bottoming Cycle 206 Additional Systems 208 Heat exchanger 210 Heat exchanger inlet line 212 Bottoming cycle inlet line 214 Heat exchanger return line 400 ways

Claims

1. A combustion system (100) comprising: a topping cycle (102); a fuel cell (106) including an anode side (112), a cathode side (116), and an electrolyte (114), the anode side (112) receiving fuel via an anode inlet line (126) to produce an anode output product containing a first portion of hydrogen, and the cathode side (116) receiving an oxidant from a cathode inlet line (118); a separation system (134) having a water gas shift reactor (135) for producing a second portion of hydrogen from the anode output product, the topping cycle (102) being fluidly coupled to the separation system (134) such that the topping cycle (102) receives the hydrogen produced from the anode output product; A combustion system (100) comprising:

2. 10. The combustion system of claim 1, wherein the cathode side receives oxidant from a cathode inlet line, the cathode inlet line being fluidly coupled to one or more of an air separation unit (ASU) or an air source.

3. The combustion system (100) of any preceding claim, wherein a cathode outlet line (168) extends from an outlet of the cathode side (116) to the cathode inlet line (118).

4. The combustion system (100) of any preceding claim, wherein the cathode inlet line (118) is fluidly coupled to an air source (158) via an air inlet line (160).

5. 2. The combustion system of claim 1, wherein a cathode outlet line extends between the cathode side and an air preheater, the air preheater being disposed on and in thermal communication with the air inlet line.

6. The combustion system (100) of any preceding claim, wherein an anode recirculation line (145) extends from the separation system (134) to the anode inlet line (126).

7. 2. The combustion system of claim 1, wherein the separation system comprises a water flash separator having a water outlet line and a liquid carbon dioxide separator having a liquid carbon dioxide outlet line, and wherein a branch line fluidly couples the cathode inlet line to the liquid carbon dioxide outlet line of the liquid carbon dioxide separator.

8. The combustion system (100) of any preceding claim, further comprising an anode steam supply (186) fluidly coupled to the anode inlet line (126) via an anode steam supply line (188).

9. 2. The combustion system of claim 1, wherein the topping cycle is a gas turbine having a compressor section, a combustion section, and a turbine section, the combustion section further comprising a heat recovery steam generator (HRSG) that receives exhaust gases from the turbine section via a turbine outlet line, the HRSG generating steam for use in a bottoming cycle.

10. The combustion system (100) of claim 1, wherein the separation system (134) further comprises a hydrogen separator (192).

11. A method (400) of operating a combustion system (100), the combustion system (100) having a fuel cell (106) with an anode side (112), a cathode side (116), and an electrolyte (114), the method (400) comprising: supplying fuel to the anode side (112) of the fuel cell (106) using an anode inlet line (126); supplying oxidant to the cathode side (116) of the fuel cell (106) using a cathode inlet line (118); producing an anode output product comprising a first portion of hydrogen using the fuel cell (106); providing the anode output product from the anode side (112) to a separation system (134), the separation system (134) comprising a water gas shift reactor (135); producing a second portion of hydrogen from the anode output product using the water gas shift reactor (135); removing water and carbon dioxide from the anode output product using the separation system (134); supplying said hydrogen to a combustion section (18) of a gas turbine engine; The method (400) includes:

12. 12. The method of claim 11, wherein supplying an oxidant further comprises supplying oxygen from an air separation unit to the cathode side of the fuel cell using the cathode inlet line.

13. 12. The method (400) of claim 11, wherein supplying an oxidant further comprises supplying atmospheric air to the cathode side (116) of the fuel cell (106) at least in part using the cathode inlet line (118).

14. Providing an oxidant supplying exhaust gas (34) from a turbine section (16) of the gas turbine (10) to the cathode side (116) of the fuel cell (106) at least in part using the cathode inlet line (118); 12. The method (400) of claim 11, further comprising:

15. 12. The method (400) of claim 11, wherein supplying fuel to the anode side (112) further comprises supplying methane to the anode side (112) of the fuel cell (106).

16. The removing step includes: removing water from said anode output product using a water flash separator (138); compressing the anode output product in a compressor (140); cooling the anode output product with a chiller (142), whereby gaseous carbon dioxide in the anode output product is condensed into liquid carbon dioxide; removing said liquid carbon dioxide from said anode output product using a liquid carbon dioxide separator (144); 12. The method (400) of claim 11, further comprising:

17. 17. The method of claim 16, further comprising supplying the liquid carbon dioxide to the cathode inlet line, the cathode inlet line being fluidly coupled to the cathode side of the fuel cell.

18. 12. The method of claim 11, further comprising: using a cathode outlet line to supply cathode output products from the cathode side to an air preheater, the air preheater being disposed on the air inlet line.

19. 12. The method (400) of claim 11, further comprising: supplying a cathode output product from the cathode side (116) to the cathode inlet line (118) using a cathode outlet line (168).

20. 1. A blue hydrogen production system, comprising: a fuel cell (106) including an anode side (112), a cathode side (116), and an electrolyte (114), the anode side (112) receiving fuel via an anode inlet line (126) to produce an anode output product containing a first portion of hydrogen, the cathode side (116) receiving oxidant from a cathode inlet line (118), and the anode side (112) receiving fuel from an anode fuel supply (128); a separation system (134) having a water gas shift reactor (135) for producing a second portion of hydrogen from the anode output product; A blue hydrogen generation system comprising:

21. 21. The blue hydrogen generation system of claim 20, wherein the cathode side (116) receives oxidant from a cathode inlet line (118), the cathode inlet line (118) being fluidly coupled to one or more of an air separation unit (ASU) (154) or an air source (158).

22. 21. The blue hydrogen generation system of claim 20, wherein a cathode outlet line (168) extends from an outlet of the cathode side (116) to the cathode inlet line (118).

23. 21. The blue hydrogen production system of claim 20, wherein the cathode inlet line (118) is fluidly coupled to an air source (158) via an air inlet line (160).

24. 21. The blue hydrogen production system of claim 20, wherein a cathode outlet line (168) extends between the cathode side (116) and an air preheater (180), the air preheater (180) being disposed on and in thermal communication with the air inlet line (160).

25. 21. The blue hydrogen production system of claim 20, wherein an anode recirculation line (145) extends from the separation system (134) to the anode inlet line (126).

26. 21. The blue hydrogen production system of claim 20, wherein the separation system (134) comprises a water flash separator (138) having a water outlet line (182) and a liquid carbon dioxide separator (144) having a liquid carbon dioxide outlet line (172), and a branch line fluidly couples the cathode inlet line (118) to the liquid carbon dioxide outlet line (172) of the liquid carbon dioxide separator (144).

27. 21. The blue hydrogen generation system of claim 20, further comprising an anode vapor supply (186) fluidly coupled to the anode inlet line (126) via an anode vapor supply line (188).

28. 21. The blue hydrogen production system of claim 20, wherein the separation system (134) further comprises a hydrogen separator (192).

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