Sorbents with high efficiency for CO2 capture based on amines-supported carbon for biogas upgrading

Sorbents for COcapture have been prepared by wet impregnation of a commercial active carbon(Ketjen-black, Akzo Nobel) with two CO-philic compounds, polyethylenimine(PEI)and tetraethylenepentamine(TEPA), respectively. The effects of amine amount(from 10 to70 wt.%), COconcentration in the feed, sorption temperature and gas hourly space velocity on the COcapture performance have been investigated. The sorption capacity has been evaluated using the breakthrough method, with a fixed bed reactor equipped with on line gas chromatograph. The samples have been characterized by Nadsorption–desorption,scanning electron microscopy and energy dispersive X-ray(SEM/EDX). A promising COsorption capacity of 6.90 mmol/gsorbenthas been obtained with 70 wt.% of supported TEPA at 70℃ under a stream containing 80 vol% of CO. Sorption tests, carried out with simulated biogas compositions(CH/COmixtures), have revealed an appreciable COseparation selectivity; stable performance was maintained for 20 adsorption–desorption cycles.