High Temperature Adsorption Materials and Their Performance for Pre-combustion Capture of Carbon Dioxide

摘要

The separation capability of carbon dioxide from high temperature syngas was evaluated using zeolite 13X, calcium chabazite and hydrotalcite materials by means of measuring isotherms and breakthrough curves under the different operating temperatures at 7 bar and assessing the performance in pressure vacuum swing adsorption (PVSA) cycles. Four different PVSA processes were designed for a dual-bed apparatus and operated at 120 °C and 200 °C. Zeolite 13X was selected for the PVSA processes due to its acceptable adsorption capacity for CO_2 at elevated temperatures and fast kinetics. CO_2 product purities ranging from 80 to 98 % were obtained from a feed gas of 12 % CO_2. From the PVSA experiments, it was found that a pressure equalisation step and product purge step improved the carbon capture performance in terms of CO_2 concentration. Contamination of the adsorbents was observed after 24 hours of operation and the contaminants originating from the syngas were identified as heavy hydrocarbons.