A method for the separation of carbon dioxide from carbon dioxide hold strength gases under pressure

摘要

CO2 is removed from gases under pressure by washing the gases first with an aqueous solution of a trialkenolamine of pH 8-10 at 50-80 DEG C., and then with an aqueous solution of an alkali metal salt of an amino acid, of pH 10-12, at 20-50 DEG C. The alkanolamine may be triethanolamine, of 25-45% concentration, and is regenerated by multi-stage flashing to atmospheric pressure, the gas from the first flashing being recompressed and recycled to the scrubbing tower. The alkali metal salt may be potassium N-methyl-a -aminopropionate, of 25-50% concentration, and is regenerated by flashing to atmospheric pressure and then stripping with steam, with heat-exchange between the solutions before and after stripping. The mixture of CO2 and steam produced is used to heat directly the alkanolamine solution after final flashing. The initial gases may be at 5-300 atm. pressure, with a minimum partial pressure of CO2 of 1.5 atm.ALSO:CO2 is removed from gases under pressure by washing the gases with an aqueous solution of an alkali metal salt of an amino acid, of pH 10 - 12, at 20-50 DEG C. The gas are first given a coarse washing with an aqueous solution of a trialkanolamine, of pH 8-10, at 50-8 DEG C. The salt may be potassium N-methyl-a -aminopropionate of 25-50% concentration, and is regenerated by flashing to atmospheric pressure and then stripping with steam, with heat exchange between the solutions before and after stripping.