Minimization of steam requirements and enhancement of water-gas shift reaction with warm gas temperature CO2 removal

A method of providing steam and absorbing CO2 for H2 production using a water gas shift reaction in a water gas shift reactor comprising:

• contacting a first gaseous stream comprising CO and CO2 with a first hydroxide in a first absorption reactor to produce a first solid carbonate and a first water product, where the first absorption reactor is at a temperature from about 150° C. to about 315° C. and where the first water product exists as a generated steam, and producing a second gaseous stream comprising CO from the first gaseous stream, an amount of CO2 less than the first gaseous stream, and the generated steam;
• discharging the second gaseous stream from the first absorption reactor into the water gas shift reactor, where the water gas shift reactor is under a temperature and pressure condition sufficient to generate the water gas shift reaction between some portion of the CO from the first gaseous stream and some portion of the generated steam to produce a third gaseous stream comprising a generated H2 and an amount of CO2 greater than the second gaseous stream, and discharging the third gaseous stream from the water gas shift reactor to a second absorption reactor;
• contacting the third gaseous stream with a second hydroxide in the second absorption reactor to produce a second solid carbonate and a second water product, where the second absorption reactor is at a temperature from about 150° C. to about 315° C., and producing a fourth gaseous stream comprising generated H2 from the third gaseous stream, the second water product, and an amount of CO2 less than the third gaseous stream;
• transferring the first solid carbonate from the first absorption reactor to a regeneration reactor, where the regeneration reactor is at a temperature of at least 375° C., and generating a first decomposition reaction by,
• heating the first solid carbonate to at least a temperature sufficient to decompose some portion of the first solid carbonate to produce a first oxide and gaseous carbon dioxide and,
• producing a third hydroxide by contacting the first oxide with steam, such that some portion of the first oxide reacts with water to produce the third hydroxide, and thereby producing a remaining first oxide, where the remaining first oxide consists of the first oxide less the some portion of the first oxide consumed to produce the third hydroxide;
• transferring the second solid carbonate from the second absorption reactor to the regeneration reactor, where the regeneration reactor is at a temperature of at least 375° C., and generating a second decomposition reaction by,
• heating the second solid carbonate to at least a temperature sufficient to decompose some portion of the second solid carbonate to produce a second oxide and gaseous carbon dioxide and,
• producing a fourth hydroxide by contacting the second oxide with steam, such that some portion of the second oxide reacts with water to produce the fourth hydroxide, thereby producing a remaining second oxide, where the remaining second oxide consists of the second oxide less the some portion of the second oxide consumed to produce the fourth hydroxide;
• discharging a rehydroxylation stream comprising some portion of the second water product from the second absorption reactor, and directing the rehydroxylation stream to a polishing reactor;
• and
• transferring the first remaining oxide and the second remaining oxide from the regeneration reactor to the polishing reactor, where the polishing reactor is at a temperature of from about 150° C. to about 315° C., and rehydroxylating the first remaining oxide and the second remaining oxide by,
• generating a first rehydroxylation reaction by contacting the first remaining oxide with a first portion of the rehydroxylation stream at a temperature sufficient to cause some portion of the first remaining oxide to react with the first portion of the rehydroxylation stream to produce a fifth hydroxide and,
• generating a second rehydroxylation reaction by contacting the second remaining oxide with a second portion of the rehydroxylation stream at a temperature sufficient to cause some portion of the second remaining oxide to react with the second portion of the rehydroxylation stream to produce a sixth hydroxide, thereby providing steam and absorbing CO2 for H2 production using the water gas shift reaction in the water gas shift reactor.

A method of providing steam and absorbing CO2 for H2 production using a water gas shift reaction in a water gas shift reactor comprising:

• contacting a first gaseous stream comprising CO and CO2 with a first hydroxide in an absorption reactor to produce a solid carbonate and a water product under a temperature condition such that the water product exists as a generated steam, and producing a second gaseous stream comprising CO from the first gaseous stream, an amount of CO2 less than the first gaseous stream, and the generated steam;
• discharging the second gaseous stream from the absorption reactor into the water gas shift reactor, where the water gas shift reactor is under a temperature and pressure condition sufficient to generate the water gas shift reaction between some portion of the CO from the first gaseous stream and some portion of the generated steam to produce a third gaseous stream comprising a generated H2, an amount of CO2 greater than the second gaseous stream, and an amount of the water product, and discharging the third gaseous stream from the water gas shift reactor;
• absorbing some portion of the CO2-comprising third gaseous stream and producing a fourth gaseous stream comprising generated H2 from the third gaseous stream and some portion of the amount of the water product, and an amount of CO2 less than the third gaseous stream;
• transferring the solid carbonate from the absorption reactor to a regeneration reactor and generating a decomposition reaction by,
• heating the solid carbonate to at least a temperature sufficient to decompose some portion of the solid carbonate to produce an oxide and gaseous carbon dioxide and,
• producing a second hydroxide by contacting the oxide with steam, such that some portion of the oxide reacts with water to produce the second hydroxide, and thereby producing a remaining oxide, where the remaining oxide consists of the oxide less the some portion of the oxide consumed to produce the second hydroxide;
• directing a rehydroxylation stream comprising a quantity of the some portion of the amount of the water product in the fourth gaseous stream to a polishing reactor;
• transferring the remaining oxide from the regeneration reactor to the polishing reactor;
• and
• rehydroxylating the remaining oxide by contacting the remaining oxide with the rehydroxylation stream at a temperature sufficient to cause some portion of the remaining oxide to react with the rehydroxylation stream to produce a third hydroxide, thereby providing steam and absorbing CO2 for H2 production using the water gas shift reaction in the water gas shift reactor.