Hydrogen Recovery from Hydrogen-Methane Gas Mixture Using Coffee Grounds Based Activated Carbon Bioadsorbent

Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI-Depok, Jawa Barat 16424, Indonesia

^* Coresponding author: msudib@che.ui.ac.id

Abstract

Hydrogen recovery from off-gas of hydrocracking unit by adsorption is one of the process that could increase the efficiency processes of refinery unit. The purpose of this research is to make coffee grounds based activated carbon bioadsorbent that will be used in hydrogen recovery proses. The carbon was prepared by chemical activation using ZnCl₂ at temperature 600°C. The surface area of produced activated carbon was measured using BET and Iodine number, while its surface morphology and composition were characterized using SEM-EDX. The adsorption capacity of activated carbon and its selectivity will be tested using hydrogen-methane gas mixture. The test was carried out on pure methane and hydrogen gas at 20°C and a mixture of CH₄/H₂ (mole ratio: 4:1) at 10°C, 20°C and 30°C and pressures from 1 to 6 bars. The results of this study show that the activated carbon can be successfully produced having the specific surface area of 728.07 m²/g and the iodine number of 2160 mg/g. The result shows that the adsorption of pure CH₄ gas at the same pressure was 2.4 times greater than pure H₂. The adsorption test indicates that the produced activated carbon might be used for hydrogen/methane separation.