Aqueous piperazine/potassium carbonate for enhanced CO2 capture

Abstract

This chapter presents experimental and modeling results for aqueous piperazine (PZ)/potassium carbonate (K2CO3) for enhanced CO2 capture from flue gas. CO2 removal by aqueous absorption/stripping is a mature technology currently used in the manufacture of ammonia and syngas. The use of aqueous K2CO3 promoted by PZ should enhance rates of CO2 absorption and reduce the heat requirement for stripping. Simple models have been developed to estimate absorber and stripper performance. The piperazine solvent can also be used to provide 90% CO2 removal with a rich loading and packing height that would give only 75% removal with monoethanolamine (MEA). Because 5m K+/2.5m PZ provides a richer solution and greater optimum capacity, the reboiler duty with 5m K+/2.5m PZ in a simple absorption/stripping process can be 25 to 46 % less that that with 7m MEA. Additional heat savings up to 6% may be achieved by operating the stripper at greater pressure.