CH_4/CO_2混合气中CH_4的变压吸附法提纯试验

Purification of CH_4 from CH_4/CO_2 Mixture by Pressure Swing Adsorption

选择几种商业化的分子筛,在常温(25℃)、低压(0.2 MPa)下,进行CH4与CO2混合气的动态吸附分离性能试验。结果表明:3A和4A分子筛对CO2的吸附量很小,而5A和13X分子筛都能较好地分离CH4与CO2。混合气在13X分子筛上的分离系数要高于5A分子筛,表明13X分子筛对CH4与CO2的分离效果更好。但5A和13X分子筛使用一次之后,都不能通过抽真空法完全再生,原因是吸附剂被吸附质毒化,红外光谱可以解释这一原因。5A和13X分子筛要成为产业化沼气净化的吸附剂,再生性能还需要进一步提高。

Selective adsorption of CO2 from its mixture with CH4 on several commercial molecular sieves was studied at ambient temperature （25℃） and low pressure （0.2 MPa）. The behaviours of the molecular sieves were compared by using three basic parameters： selectivity, adsorption capacity and regenerability. The results indicate 3A and 4A molecular sieves have low COz adsorption capacity. However 5A and 13X molecular sieves show high efficiency in dynamic separation of CH4 and CO2 when the adsorbents are used for the first time. The separation coefficient between CH4 and COs on 13X molecular sieve is higher than 5A, which proves 13X molecular sieve show better performance in separating COs from its mixture with CH4. But 5A and 13X molecular sieve could not be regenerated completely by vacuuming and the adsorption/regeneration performance became stable from their second use. The reason why separation performance of 5A and 13X molecular sieves decrease is explained by FTIR spectroscopy that the partial poisoning of the molecular sieves happened. That is to say the regenerability of the two molecular sieves need improve.