PSA System for the Recovery of Carbon Dioxide from Blast Furnace Gas in Steel Works The Influence of Operation Conditions on CO2 Separation

In Japan, steel works discharge carbon dioxide about 15% of total discharging amount. For reducing CO2 emission, development of separation and recovery technology of carbon dioxide from blast furnace gas by utilizing PSA technology is in progress. At first, 14 kinds of adsorbents from the market are evaluated by adsorption isotherms. It was found that zeolite called "Zeolum F-9" was suitable for carbon dioxide separation with its higher carbon dioxide adsorption capacity and selectivity. Then, Zeolum F-9 was evaluated with laboratory PSA testing apparatus. PSA was operated with 3 steps, that is, "adsorption," "purge" and "desorption" step to separate carbon dioxide from mixed gas, which composition was similar to blast furnace gas. The influence of the three PSA operation factors on CO2 purity and yield were evaluated. 1) The ratio of Feed gas flow and adsorbent weight ratio effects on CO2 recovery. The CO2 recovery was proportional to the raito until to some extent. Over that, the CO2 recovery became constant. 2) The concentration of CO2 in the feed gas was evaluated. The time of purging decreased (purge gas decreased), so that CO2 concentration in the feed gas was increased. 3) The effect of moisture in the feed gas was evaluated. At first, CO2 yield decreased, but after that, CO2 yield became constant. It was explained that supplied water adsorbed and desorbed on the adsorbent such like other gas species and no effect on the CO2 separation. COURSE 50 project including this study is conducted under the financial support of NEDO (New Energy and Industrial Technology Development Organization in Japan).