Process analysis of temperature swing adsorption and temperature vacuum swing adsorption in VOCs recovery from activated carbon

In order to better guide the design of industrial process for purification and recovery of VOCs, tempera-ture swing adsorption (TSA) and temperature vacuum swing adsorption (TVSA) process for VOCs purifi-cation and recovery were studied systematically with activated carbon adsorbent. The adsorption and desorption behaviors of benzene on activated carbon in above two processes were investigated system-atically. Effects of operating parameters on process performances were further analyzed, including as regeneration temperature, purging feed ratio and hot-cold purging ratio. The results showed that the increase of hot-cold purging ratio (HP/CP) could obtain the same regeneration effect as the increase of desorption temperature. Increasing the feed purge ratio without increasing the hot-cold purging ratio is not conducive to bed regeneration, because a large number of cold purge gases cannot utilize the resid-ual heat of temperature wave, thus reducing the desorption effect of the cooling step on the bed. In addi-tion, the vacuum step can enhance the regeneration ability of hot nitrogen to the bed at the same regeneration temperature, making the bed regeneration of TVSA process more thorough. Temperature in the middle and lower part of the bed in TVSA process was higher and the regeneration was more thor-ough. In conclusion, TVSA has more obvious advantages than TSA in terms of energy consumption, hot or cold purge volume and bed regeneration.(c) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

This study systematically investigated the temperature swing adsorption (TSA) and temperature vacuum swing adsorption (TVSA) processes for VOCs purification and recovery using activated carbon adsorbent. The adsorption and desorption behaviors of benzene on activated carbon in these processes were studied. The effects of operating parameters on process performances were analyzed, and it was found that TVSA has advantages over TSA in terms of energy consumption, purge volume, and bed regeneration.