Enhanced Pressure Swing Membrane Absorption Process for CO2 Removal from Shifted Syngas with Dendrimer–Ionic Liquid Mixtures as Absorbent

Abstract

Using pure ionic liquid [bmim][DCA] or its dendrimer-containing solutions as absorbents, studies of a novel five-valve pressure swing membrane absorption (PSMAB) process for CO2 removal from lower temperature shifted syngas were carried out with porous hydrophobized polyether ether ketone (PEEK) hollow fiber based membrane modules. At first how the preferred absorption step duration in each cycle was determined was presented. Then we investigated the effects of the following aspects of the membrane module: reducing the tube-side dead volume in the hollow fiber module; decreasing the fiber packing density leading to increased absorbent liquid layer thickness around any fiber; increasing the tube-side gas volume. All three design features in the membrane module greatly enhanced the gas absorption behavior and improved the product qualities. Increasing temperature reduced the product qualities when pure [bmim][DCA] was used. Adding polyamidoamine (PAMAM) dendrimer Gen 0 to the ionic liquid greatly improved i...