Sorption of CO2, C2H2 and C2H4 in HOF-1a studied by PHSC equation of state

Abstract

Acetylene is a byproduct of modern ethylene production by cracking of hydrocarbons. There are extensive research efforts to exchange solvent extraction and hydrogenation methods for removing acetylene from ethylene with cost-effective membrane separation technology. Recently, the first Hydrogen-bonded Organic Framework (HOF) has been established to examine its capacity for acetylene uptake. In this study, Perturbed Hard Sphere Chain equation of state (PHSC) has been selected to obtain volumetric data for CO2, C2H2 and C2H4 sorption on HOF-1a system. Three molecular-based parameters including hard-sphere diameter (σ), the non-bonded interaction energy (ɛ) and number of segments per molecule (r) have been employed as scaling constants and calculated using group contribution (GC) method. High capacity of HOF-1a has been demonstrated for C2H2/C2H4 separation. C2H2 and C2H4 coupling effects in the mixed gas sorbed in HOF-1a, have been extracted from PHSC EoS for mixture sorption. The sorption of acetylene decreases in the presence of ethylene while sorption of ethylene increases in the presence of acetylene. HOF-1a has high capacity to sorb C2H2 as an impurity in industrial gas separation, but its low selectivity causes the loss of ethylene which makes it economically detrimental.