21-10-2014, 02:46 PM
Abstracts: In ammonia plant, absorption of carbon dioxide is one of important step for manufacturing ammonia from natural gases. As carbon dioxide is poisonous for synthesis of ammonia it should be removed from synthesis gases to obtain ammonia. Ammonia and carbon dioxide are used in production of urea. Carbon dioxide is an undesirable constituent in the synthesis gas because it poisons the Ammonia synthesis catalysts. CO2 content in the synthesis gas therefore must be reduced to 5 to 10 ppm by volume. CO2 absorption is carried out by selective absorption after the low temperature shift conversion. The CO2 removal processes are based on chemical and Physical absorption of CO2 in a solvent. There are number of processes available to remove CO2 from the synthesis gas. Based on the process used, the gas absorption can be classified as Physical or Chemical absorption process.