Capture of CO2 from flue gas by vacuum pressure swing adsorption using activated carbon beads

Abstract

Vacuum pressure swing adsorption (VPSA) for CO 2 capture has attracted much research effort with the development of the novel CO 2 adsorbent materials. In this work, a new adsorbent, that is, pitch-based activated carbon bead (AC bead), was used to capture CO 2 by VPSA process from flue gas. Adsorption equilibrium and kinetics data had been reported in a previous work. Fixed-bed breakthrough experiments were carried out in order to evaluate the effect of feed flowrate, composition as well as the operating pressure and temperature in the adsorption process. A fourstep Skarstrom-type cycle, including co-current pressurization with feed stream, feed, counter-current blowdown, and counter-current purge with N 2 was employed for CO 2 capture to evaluate the performance of AC beads for CO 2 capture with the feed compositions from 15-50% CO 2 balanced with N 2 . Various operating conditions such as total feed flowrate, feed composition, feed pressure, temperature and vacuum pressure were studied experimentally. The simulation of the VPSA unit taking into account mass balance, Ergun relation for pressure drop and energy balance was performed in the gPROMS using a bi-LDF approximation for mass transfer and Virial equation for equilibrium. The simulation and experimental results were in good agreement. Furthermore, two-stage VPSA process was adopted and high CO 2 purity and recovery were obtained for post-combustion CO 2 capture using AC beads.

Electrocatalytically Switchable CO2 Capture: First Principle Computational Exploration of Carbon Nanotubes with Pyridinic Nitrogen

“…[5,6] The newly developed solid adsorbent method and vacuum swing adsorption represent an improvement characterized by lower energy requirement and alleviation of equipment corrosion. [7][8][9][10][11][12][13][14][15][16][17] However, these routes all include a regeneration process that usually involves increasing the temperature of the adsorbents after CO 2 capture to release CO 2 , accounting for the bulk of the capture cost. Inevitably, a thermochemically driven high CO 2 selectivity is associated with large adsorption energy and, consequently, a high input energy for regeneration.…”

Feasibility of Using Adsorbent-Coated Microchannels for Pressure Swing Adsorption: Parametric Studies on Depressurization

“…With D h of 600 µm, the CO 2 removal capacity is nearly twice the feed throughput documented by Kapoor and Yang 13 for the first two cases shown in Table 7(a) and 7(b), and nearly four times as the vacuum pressure is decreased to 1 kPa. 20 because they report CO 2 captured during depressurization. The depressurization stage model developed in the present work is modified and used for their process conditions and a comparative assessment is shown in Table 8(a) to (c).…”

“…Intra-crystalline diffusivity of the gases in the adsorbent is a function of activation energy and adsorbent layer temperature and can be determined using Equation (19). The constant, K LDF , is then used in Equation (20) to determine the instantaneous rate of adsorption. Heat of adsorption of component gases on zeolite 5A crystals is calculated using Equation (21) 33 .…”

Pressure Swing Adsorption Technologies for Carbon Dioxide Capture

“…The only difference is that the former utilizes porous solid adsorbents such as zeolites or actived carbon during CO 2 capture, in which, chemical reactions between the adsorbent and CO 2 may or may not present during the separation [19][20][21]. The main advantage of physical adsorption over chemical absorption is its simple and energy efficient operation and regeneration, which can be achieved simply by a pressure swing.…”