Power generation using hydrogen fuel with economical carbon dioxide capture

Abstract

Systems and methods for generating power using hydrogen fuel, such as derived from natural gas, are provided. Feed materials are introduced into a compact hydrogen generator to produce carbon dioxide and hydrogen gas. Sorbent material within the compact hydrogen generator acts to absorb carbon dioxide, forming a used sorbent. The hydrogen gas is separated from the used sorbent and passed to a power generator such as a hydrogen turbine to produce power. The used sorbent is introduced into a calciner and heated to desorb carbon dioxide and form a regenerated sorbent which can be recycled to the compact hydrogen generator.

What is claimed is: 
     
         1 . A system for power generation, the system comprising:
 a compact hydrogen generator, the compact hydrogen generator containing a quantity of a sorbent material, wherein a feed material produces H 2  product and carbon dioxide and the sorbent material absorbs carbon dioxide and forms a used sorbent;   a gas/solids separator connected to the compact hydrogen generator to separate the H 2  product and the used sorbent;   a calciner connected to the gas/solids separator to heat the used sorbent to desorb carbon dioxide from the used sorbent to produce regenerated sorbent;   a recycle line to introduce at least a portion of the regenerated sorbent from the calciner to the compact hydrogen generator; and   at least one power generator to receive and utilize at least a portion of the H 2  product from the gas/solids separator to produce power.   
     
     
         2 . The system of  claim 1  wherein the compact hydrogen generator comprises a fluidized bed, sorbent enhanced reformer. 
     
     
         3 . The system of  claim 1  wherein the compact hydrogen generator containing the sorbent material comprises a bubbling fluidized bed of the sorbent material and a reforming catalyst for catalytic conversion of methane to the H 2  product, wherein the reforming catalyst and the sorbent material are sized for the reforming catalyst to remain in the fluidized bed while the H 2  product and used sorbent are conveyed to the gas/solids separator. 
     
     
         4 . The system of  claim 1  wherein the H 2  product and used sorbent are conveyed to the gas/solids separator by elutriation. 
     
     
         5 . The system of  claim 1  wherein the feed material comprises natural gas and steam. 
     
     
         6 . The system of  claim 5  wherein the natural gas comprises sulfur, said system additionally comprises:
 a desulfurizer to remove sulfur from the natural gas prior to passage to the compact hydrogen generator. 
 
     
     
         7 . The system of  claim 1  wherein the calciner is an indirect heating calciner. 
     
     
         8 . The system of  claim 1  wherein the at least one power generator comprises a gas turbine or a hydrogen turbine and produces a flue gas, wherein said system additionally comprises a heat recovery steam generator connected to the at least one power generator to accept at least a portion of the flue gas, recover heat from the flue gas and generate steam. 
     
     
         9 . The system of  claim 1  wherein the compact hydrogen generator operates at a pressure of at least 35 psia to produce the H 2  product and carbon dioxide. 
     
     
         10 . The system of  claim 1  wherein the calciner operates at atmospheric pressure to heat the used sorbent to desorb carbon dioxide from the used sorbent to produce regenerated sorbent. 
     
     
         11 . The system of  claim 1  wherein the calciner heats the used sorbent to desorb high purity carbon dioxide from the used sorbent. 
     
     
         12 . The system of  claim 1  additionally comprising:
 a H 2  purifier to purify at least a portion of the H 2  product from the gas/solids separator to form purified H 2  product; 
 a storage vessel to temporarily store at least a portion of the purified H 2  product; and 
 a first process line to selectively pass a portion of the temporarily stored H 2  product from the storage vessel to the at least one power generator. 
 
     
     
         13 . The system of  claim 1  wherein the at least one power generator is a turbine. 
     
     
         14 . The system of  claim 1  wherein the at least one power generator is a hydrogen turbine. 
     
     
         15 . The system of  claim 1  wherein the at least one power generator is a reciprocating engine. 
     
     
         16 . A system for power generation from natural gas via use of hydrogen fuel, the system comprising:
 a compact hydrogen generator for generating H 2  product from feed materials comprising natural gas and steam, the compact hydrogen generator comprising a bubbling fluidized bed of sorbent material and reforming catalyst for catalytic conversion of methane to the H 2  product, wherein the feed materials produce the H 2  product and carbon dioxide and the sorbent material absorbs carbon dioxide and forms a used sorbent;   a gas/solids separator connected to the compact hydrogen generator to separate the H 2  product and the used sorbent;   an indirect calciner connected to the gas/solids separator to heat the used sorbent to desorb carbon dioxide from the used sorbent to produce regenerated sorbent and a quantity of high purity carbon dioxide;   a recycle line to introduce at least a portion of the regenerated sorbent from the indirect calciner to the compact hydrogen generator; and   at least one power generator to receive and utilize at least a portion of the H 2  product from the gas/solids separator to produce power.   
     
     
         17 . The system of  claim 16  wherein the compact hydrogen generator operates at a pressure of at least 35 psia to produce the H 2  product and carbon dioxide and the calciner operates at atmospheric pressure to heat the used sorbent to desorb carbon dioxide from the used sorbent to produce regenerated sorbent and high purity carbon dioxide. 
     
     
         18 . A method for producing power via hydrogen gas, said method comprising:
 introducing feed material into a sorbent enhanced reformer to produce H 2  product and carbon dioxide, the sorbent enhanced reformer containing a quantity of a sorbent material to absorb carbon dioxide and form a used sorbent;   introducing the H 2  product and used sorbent from the sorbent enhanced reformer to a gas/solids separator to separate the H 2  product from the used sorbent;   introducing at least a portion of the separated H 2  product to at least one power generator to produce power;   introducing at least a portion of the separated used sorbent to a calcines to heat the used sorbent to desorb carbon dioxide from the used sorbent to produce regenerated sorbent and CO 2 ; and   recycling at least a portion of the regenerated sorbent to the sorbent enhanced reformer.   
     
     
         19 . The method of  claim 18  wherein the sorbent enhanced reformer comprises a bubbling fluidized bed of the sorbent material and a reforming catalyst for catalytic conversion of methane to the H 2  product. 
     
     
         20 . The method of  claim 19  wherein the sorbent material and the reforming catalyst are sized for the reforming catalyst to remain in the fluidized bed while the H 2  product and used sorbent are conveyed to the gas/solids separator. 
     
     
         21 . The method of  claim 18  wherein the introducing of at least a portion of the separated used sorbent to the calciner to heat the used sorbent to desorb carbon dioxide from the used sorbent produces heated regenerated sorbent and CO 2  and wherein said recycling comprises recycling heated regenerated sorbent to the sorbent enhanced reformer. 
     
     
         22 . The method of  claim 18  wherein the feed material comprises natural gas and steam. 
     
     
         23 . The method of  claim 22  wherein the natural gas comprises sulfur, said method additionally comprises:
 removing sulfur from the natural gas prior to introduction into the sorbent enhanced reformer. 
 
     
     
         24 . The method of  claim 18  wherein calciner is an indirect heat calciner and the separated used sorbent introduced into the calciner is subjected to indirect heat in the calciner. 
     
     
         25 . The method of  claim 18  wherein the at least one power generator comprises a gas turbine or a hydrogen turbine and produces a flue gas, wherein said method additionally comprises introducing at least a portion of the flue gas into a heat recovery steam generator connected to the at least one power generator to recover heat from the flue gas and generate steam. 
     
     
         26 . The method of  claim 18  wherein the compact hydrogen generator operates at a pressure of at least 35 psia to produce the H 2  product and carbon dioxide. 
     
     
         27 . The method of  claim 18  wherein the calciner operates at atmospheric pressure to heat the used sorbent to desorb carbon dioxide from the used sorbent to produce regenerated sorbent. 
     
     
         28 . The method of  claim 18  additionally comprising:
 purifying at least a portion of the H 2  product from the gas/solids separator to form purified H 2  product; 
 temporarily storing at least a portion of the purified H 2  product; and 
 selectively passing a portion of the temporarily stored H 2  product to the at least one power generator. 
 
     
     
         29 . The method of  claim 28  wherein the selective passing of a portion of the temporarily stored H 2  product to the at least one power generator occurs in response to peak power production demands. 
     
     
         30 . The method of  claim 18  wherein the CO 2  desorbed from the used sorbent is high purity carbon dioxide. 
     
     
         31 . The method of  claim 30  additionally comprising:
 conveying at least a portion of the high purity carbon dioxide for use in one or more of enhanced oil recovery, urea production, and beverage production. 
 
     
     
         32 . The method of  claim 18  wherein the at least one power generator is a turbine. 
     
     
         33 . The method of  claim 18  wherein the at least one power generator is a hydrogen turbine. 
     
     
         35 . The method of  claim 18  wherein the at least one power generator is a reciprocating engine. 
     
     
         36 . The method of  claim 18  wherein the H 2  product and used sorbent are conveyed to the gas/solids separator by elutriation.