Patent ID: 8388919

Claim:
A process that removes carbon dioxide from a pre-combustion gas stream of a processing plant, the gas stream including steam and carbon dioxide, the process including the steps of: a) extracting carbon dioxide from the gas stream by contacting the gas stream with an absorbing medium in the form of an alkali carbonate absorbent solution so as to produce a gas stream lean in carbon dioxide; b) volatilizing carbon dioxide from the absorbing medium so as to produce a product stream rich in carbon dioxide; c) obtaining energy from the gas stream in the form of either one or a combination of i) sensible heat from the gas stream and/or ii) latent heat obtained by condensing steam and using the energy as a heat source to assist in volatilization of carbon dioxide according to step b); and d) controlling the temperature of the absorbing medium fed to an absorber in which step a) is being carried out to a starting temperature in the range of 120 to 250° C. and, in turn, control partial pressure (or mass fraction) of water of the gas stream lean in carbon dioxide; wherein step a) is carried out at a pressure ranging from 1,000 to 8,000 kPa absolute.