Adsorption behaviour of molecular sieve and activated carbon for CO2 adsorption at cold temperatures

• Published in: Carbon Neutrality (Online) 2022-12, Vol.1 (1), Article 16
• Main Authors: Wang, Shiqing, Wang, Yutong, Kuang, Yue, Xu, Shisen, Gao, Shiwang, Liu, Lianbo, Niu, Hongwei, Xiao, Ping, Huang, Bing
• Format: Article
• Language: English
• Subjects: Climate Change; Energy; Environmental Science and Engineering; Original Article
• ISSN: 2731-3948; 2731-3948
• DOI: 10.1007/s43979-022-00017-5

At present, insufficient works have provided insights into the application of adsorption to remove CO 2 in flue gas below room temperatures under ambient pressure. In this work, the effects of temperature, CO 2 partial pressure and moisture on dynamic adsorption characteristics for CO 2 are conducted for various adsorbents. Based on our findings, lower the adsorbing temperature can drastically enhance the adsorption of carbon dioxide over molecular sieves and activated carbon. Among various adsorbents, 13X molecular sieve shows highest adsorption capacity. With a concentration of 10% CO 2 in flue gas, the specific adsorption capacity of CO 2 over 13X molecular sieve is 0.11, 2.54 and 5.38 mmol/g at 80 °C, 0 °C and − 80 °C, respectively. In addition, the partial pressure of CO 2 also has a significant impact on the adsorption capacity. With the increment of the concentration of CO 2 from 1% to 10% under 0 °C, the specific capacity of 13X molecular sieve increases from 1.212 mmol/g to 2.538 mmol/g. Water vapor in flue gas can not only reduce the specific adsorption capacity of CO 2 due to competing adsorption, but also increase the heat penalty of molecular sieve regeneration due to the water adsorption. An overall analysis is conducted on the energy penalty of capture 1 ton CO 2 at various adsorption temperatures between − 80 °C and 80 °C, considering both the heat penalty of molecular sieve regeneration as well as the energy penalty for cooling the adsorber. It is found that the lowest energy penalty is about 2.01 GJ/ton CO 2 when the adsorption is conducted at 0 °C.