Analysis of the impact of operational and design variables on the biogas upgrading process from a binary mixture

Abstract

In the present work, a mathematical model of a countercurrent membrane used in the methane recovery for biogas upgrading is presented. This model is implemented in GAMS (General Algebraic Modeling System), and its objective was to simulate a CO₂|CH₄ mixture separation. A parametrical analysis of the behavior of the efficiency variables of the separation such as CH₄ recovery and purity on the retentate, and stage-cut. Starting from a base-case, the feed pressure, the membrane area, the feed composition, CO₂ permeance and CO₂|CH₄ selectivity are varied. In every case high CH4 recoveries and purities (>70%) are obtained, while a greater influence of the pressure than the membrane area on the separation efficiency variables is observed. It is also observed that the greater the permeance the greater the purity.