Two-Stage VPSA Process for CO₂ Capture from Flue Gas Using Activated Carbon Beads

Abstract

Carbon dioxide removal from flue gas with a two-stage vacuum pressure swing adsorption (VPSA) process, which uses activated carbon (AC) beads as the adsorbent, was investigated both theoretically and experimentally. First, single-column VPSA experiments were studied for CO 2 /N 2 separation with high CO 2 feed concentration. Then, a two-stage VPSA process composed two columns for each stage was designed, and the effects of different parameters were investigated. The first-stage VPSA unit operates with a four-step Skarstrom cycle, which includes feed pressurization, adsorption, blowdown, and countercurrent purge with N 2 . For the second-stage VPSA process, a cycle with feed pressurization, adsorption, pressure equalization, blowdown and pressure equalization was employed. With the proposed two-stage VPSA process, a CO 2 purity of 95.3% was obtained with 74.4% recovery. The total specific power consumption of the two-stage VPSA process is 723.6 kJ/kg-CO 2, while the unit productivity is 0.85 mol-CO 2 /kg•h.

Advances in Pressure Swing Adsorption for Gas Separation

“…Many researchers around the world are 7 currently working on CO 2 capture from flue gases. It has been potentially demonstrated that CO 2 can be captured using PSA [224][225][226][227] but more fundamental and long-term pilot plant studies are required to properly benchmark this technique against amines. Also, olefin-paraffin separation by adsorption was quite studied, but the energetic consumption of the separation by adsorption is still comparable to distillation [228].…”

Effect of Gas Recycling on the Performance of a Moving Bed Temperature-Swing (MBTSA) Process for CO2 Capture in a Coal Fired Power Plant Context

“…The adsorption equilibrium of the gases onto the solid is described by the Virial adsorption model, which presents the following extension of single component equilibrium to predict multi component systems [13][14][15][16]:…”

Low-temperature solid carbon dioxide carriers

“…Carbon materials such as activated carbon (Shen, Liu, Li, & Yu, 2012), CNT (Lu, Bai, Wu, Su, & Hwang, 2008) and multiwalled CNT (Gui, Yap, Chai, & Mohamed, 2013) can be used to capture CO 2 by physical adsorption. Activated carbon is the most widely investigated classes of adsorbents in previous studies (Shen et al, 2012).…”

“…Activated carbon is the most widely investigated classes of adsorbents in previous studies (Shen et al, 2012). Although the CO 2 uptake and selectivity of activated carbon are low at lower pressures, the low heats of adsorption and the stability of carbon adsorbents make them competitive for CO 2 capture from flue gas.…”