沼气变压吸附剂吸附性能比较

研究了工程上常用的3种吸附剂CO2吸附剂硅胶、13X分子筛和碳分子筛在高压(0.1~1 MPa)下对CO2和CH4的吸附容量、稳定性和选择性，以确定其在沼气变压吸附分离中应用的可行性. 结果表明，硅胶的吸附稳定性非常好，0.1 MPa时吸附选择性系数为8~10，能有效分离CH4?CO2；13X分子筛对CH4和CO2吸附容量最高、吸附选择性最好，重复使用5次CO2的吸附容量略有下降；以CH4的损失率作为评价标准时，13X分子筛吸附CH4的损失率最低. 降压不能使被碳分子筛吸附的CH4完全解吸，吸附位不能充分释放，不适用于CH4与CO2的分离.

Comparation of Adsorption Properties of Pressure Swing Sorbents for Biogas

The adsorption capacity, adsorption stability and adsorption selectivity under high pressure (0.1~1 MPa) of three sorbents, silica gel, 13X molecular sieves and carbon molecular sieves, which were potentially used in biogas upgrading engineering, were investigated. The results showed that among the three adsorbents, silica gel had the best adsorption stability, and its adsorption selectivity coefficient under 0.1 MPa was between 8 and 10 which can achieve a effective separation of CO2 from CH4. 13X molecular sieve had the highest adsorption capacity for both CO2 and CH4, in addition, 13X molecular sieves had a significantly improved selectivity, however, the adsorption capacity for CO2 decreased continually when reused 5 times. When taking the environmentally important CH4 slip into account, 13X molecular sieve was the lowest. The desorption isotherms of carbon molecular sieves were always above the adsorption isotherm when reused for CH4 which means that the adsorbed CH4 and the adsorption sites cannot be fully released through depressurization, so it was not a good candidate for CO2/CH4 separation.