Method and apparatus for gasification with CO₂recovery

摘要

Gasification of carbon-containing raw material into gasified gas and recovery of CO2 are enabled at the same pressure throughout a system.;Provided are a hydration tower 1 for performing hydration reaction by contact of CaO with water vapor while keeping at a predetermined pressure and a temperature at or below an upper limit for production of Ca(OH)2; a gasification reactor 2 with a water removal section 2a for dehydration of Ca(OH)2 introduced through heating to obtain highly active CaO and with a gasification section 2b for production of char through reaction of a raw material with water vapor and production of gasified gas through gasification of the char, CO2 being absorbed by CaO from the section 2a to produce CaCO3, heat of reaction at that time being used for the gasification of the raw material, the gasified gas being used as a heat source for the dehydration in the section 2a; and an absorbent regeneration tower 3 in which, in the presence of the char-containing CaCO3 from the section 2b, CO2, water vapor and oxygen, CaCO3 is calcined with heat of combustion of the char to separate it into CO2 and CaO, the resultant CaO being supplied to the hydration tower 1. The pressure in the reactor 2 and in the tower 3 connected to the tower 1 is the same as pressure in the tower 1.

主权项

1. A method for gasification with CO2 recovery, comprising:
a hydration process for performing a hydration reaction by contact of a CO2 absorbent with water vapor while keeping a predetermined pressure and maintaining a temperature at or below an upper limit for production of an absorbent hydrate; a water removal process in which the absorbent hydrate produced by the hydration process is introduced to be heated for water removal, thereby obtaining a highly active absorbent; a gasification process for producing char through reaction of a raw material with water vapor and for gasifying the char to produce a gasified gas, CO2 being absorbed by said highly active absorbent from said water removal process to produce an absorptive-reaction product, heat of the reaction at this time being utilized for gasification of said raw material, said gasified gas being passed through said water removal process for supply of a heat source for water removal from the absorbent hydrate; an absorbent regeneration process in which, in the presence of the absorptive-reaction product including the char from said gasification process, a circulation gas including CO2 and water vapor and oxygen, the absorptive-reaction product is calcined with heat of combustion of the char for separation into CO2 and CO2 absorbent, a resultant CO2 absorbent being supplied to said hydration process; and a CO2 recovery process for extracting and recovering a portion of CO2 separated by said absorbent regeneration process and circulated to said gasification process and to said absorbent regeneration process; pressure in said water removal process, said gasification process and said absorbent regeneration process being the same as pressure in said hydration process.