Impact of fixed bed reactor orientation, liquid saturation, bed volume and temperature on the clathrate hydrate process for pre-combustion carbon capture

摘要

Hydrate based gas separation (HBGS) process is a promising technology for carbon capture from pre-combustion streams of power generation. Recently, fixed bed reactor (FBR) configuration has been reported to significantly enhance the kinetics of hydrate formation for the HBGS process. In this work, silica sand bed reactor was employed along with 5.56 mol% THF solution to capture CO2 from fuel gas mixture (CO2/H-2) at 6.0 MPa, to investigate the effects of reactor orientation (vertical, horizontal), liquid saturations in the bed (50%, 75%, 100%), and fixed bed volume. Horizontal configuration showed a major improvement in terms of gas uptake and normalized rate of hydrate formation than vertical configuration, due to the larger cross sectional area in the horizontal configuration. 50% liquid saturation performed better than the other saturations from water utilization perspective, whereas 100% saturation was better from space utilization perspective. While bed volume did not influence the kinetics of hydrate formation much, smaller bed volume showed better dissociation kinetics. In addition, the effect of operating temperatures (279.2 K, 282.2 K and 285.2 K) were evaluated for a chosen configuration. Operating temperature of 282.2 K presented slightly lower performance compared with 279.2 K, but had the advantage of energy saving. The short induction time and high CO2 composition in hydrate phase (more than 91%) further enhanced the potential and feasibility of employing this horizontal FBR configuration for pre-combustion CO2 capture with the use of THF. (C) 2016 Elsevier B.V. All rights reserved.