Process Safety and Environmental Protection, Vol.135, 273-281, 2020
Enhanced removal and recovery of binary mixture of n-butyl acetate and p-xylene by temperature swing-Vacuum pressure swing hybrid adsorption process
The adsorption and desorption behaviors of two polar-nonpolar typical VOCs (n-butyl acetate and p-xylene) on activated carbon have been investigated by a temperature swing-vacuum pressure swing adsorption (TS-VSA) hybrid process. This hybrid process allows the maximal concentration enrichment (desorbed concentration to feed concentration ratio) of n-butyl acetate (BAC) and p-xylene (PX) to increase from 9.6 to 22.7 and 9.0 to 18.6, respectively. This enrichment could not only significantly improve the desorption efficiency of the total adsorbed VOC mixture (over 30 %) compared with those of single TSA (Temperature swing adsorption) or VSA (vacuum pressure swing adsorption), but also reduce the desorption time and energy consumption. Based on the thermodynamic adsorption properties of n-butyl acetate and p-xylene, the optimized desorption conditions are determined to be at 65 degrees C, 7.0 kPa and 0.85 L/min of stripping gas. The recycling tests further show that the activated carbon could stably run for the removal and recovery of VOCs using this hybrid process with over 85 % of adsorption capacity being kept. This test suggests that the TS-VSA hybrid process would be promising process for the engineering removal and recovery of VOCs (single component or mixtures) using activated carbons or other adsorbents. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.