Intensification of catalytic CO2 methanation mediated by in-situ water removal through a high-temperature polymeric thin-film composite membrane

Abstract

[EN] Catalytic CO2 methanation technology can be improved by process intensification, i.e. enabling higher energy efficiency and process sustainability. Here, thin-film composite membranes (TFCM) were developed for in-situ water removal in a catalytic membrane reactor (CMR) for the Sabatier process. The selective separation layer (1.4 mu m-thick) of the composite membrane is made of the polyimide 6FDA-6FpDA, a glassy polyimide, which exhibits high permeability and selectivity together with stable function at unprecedented high temperatures (>200 degrees C), compared to polyimides reported until now (90 degrees C), thus matching the temperature range of Sabatier reactors. Remarkably, TFCM developed in this work, allow to extract an outstanding amount of water up to 1 m(3)/(m(2).h.bar) at 260 degrees C. TFCM was implemented for the water removal from the methanation reaction in a CMR operated at 260 degrees C and using Ni-Todomkite as catalyst. The TFCM-mediated water-extraction enabled to raise both catalytic stability and activity during CMR operation. CO2 conversion stability was greatly improved exhibiting a conversion value of 72 % during the course of the reaction (21 % increase in CO2 conversion), with a water removal of 12.5 % and specific flux of similar to 100 g.h(-1) m(-)(2).