24 / 2015-11-19 18:20:18

Poly-amino-based ionic liquids coupled with semi-coke for biogas upgrading

8378,8379,8380,8381,8382,8383

Poly-amino-based ionic liquid (IL) [TETAH]+[BF4]- was mixed with sodium hydroxide solution for CO2 separation from biogas in a spray scrubber packed with modified semi-coke. Relatively low absorbent concentration and a mole percentage of 20 % IL were advised for improving CO2 absorption. A CO2 absorption capacity of 0.92mol was achieved when controlling the outlet CO2 concentration below 3 vol%. Water in solution promoted the reaction between IL-amine and CO2, but such promotion was limited by high absorbent concentration. The porous structure of semi-coke contributed to improving CO2 absorption. Nitric acid oxidation and heat treatment could increase the specific surface area, enlarge the intrinsic pores and develop more micropores. Semi-coke firstly oxidized by nitric acid and then with heat treatment could not only exhibit higher specific surface area and more porous structure, but also show less degree of graphitization, which was suggested as possible to increase the reactivity to CO2. It was assumed that the absorption system in this research showed promising application in CO2 separation from biogas.