A new energy-efficient process for carbon capture from flue gases and biogas at atmospheric pressure using physical absorption in cross-flow hollow fiber membrane contactors

A new carbon capture process operating at atmospheric pressure has been designed and modeled. The process is based on physical absorption using cross-flow hollow fiber membrane contactors. Simulations of the separation of CO 2 -N 2 and CO 2 -CH 4 mixtures using water as a solvent at 5 °C and 20 °C were carried out, demonstrating the suitability of the process for treating combustion gases and purifying biogas. For CO 2 -N 2 mixtures at 20 °C, with CO 2 inlet mole fractions between 0.09 and 0.35, the energy requirement of the new process, related to vacuum pumping, is between 0.29 and 0.98 GJ per ton of CO 2 captured. This is significantly lower than the reference technology for treating atmospheric flue gases, namely chemical absorption, which requires between 3.0 and 5.5 GJ per ton of CO 2 captured. Refrigeration at 5 °C further reduces energy demand by up to 27%. Considering the geometry of the commercial Liqui-Cel TM EXF hollow fiber membrane modules, the volumetric footprint of the equipment is similar to that used for chemical absorption. The specific energy demand of the process for biogas treatment is between 0.044 and 0.052 kWh per Nm 3 of raw biogas. This value is approximately four times lower than the energy demand of current biogas upgrading technologies, which is between 0.2 and 0.3 kWh per Nm³ of raw gas. Given its low energy consumption and small footprint, the membrane process developed in this article, represents a promising advancement in the field of carbon capture technologies.