PENURUNAN KONSENTRASI GAS CO2 PADA BIOGAS DENGAN METODE ABSORPSI MENGGUNAKAN LARUTAN Ca(OH)2

Biogas is one of renewable energy resources from anaerobic digestion of biological wastes. It has been used to provide shaft power, heat, and electricity. Biogas contains approximately 50-65% methane (CH4), 30-45% carbon dioxide (CO2), moisture and traces of hydrogen sulphide (H2S). Presence of non methane gas such as CO2 and H2S in biogas affects engine performance adversely, corrosive, toxic, and economically inefficient. Reducing CO2 content will significantly improve quality of biogas. In this research, a method for CO2 removal and CH4 enrichment is presented by scrubbing process. Chemical absorption of CO2 by aqueous solutions in a packed column was experimentally investigated. The aqueous solutions as absorbent in this work is Ca(OH)2 or calcium hydroxide from local resources with purity is 79%. Liquid solvents were circulated through the column, contacting the biogas in countercurrent flow with plastic Rachig rings 5/16 inch as packed column in 5 cm diameter of column. Factors that investigated in this research are concentration of absorbent, temperature of absorbent, flow rate of absorbent and gas, and high level of column. Absorption characteristics were examined by titration and pH meter investigation. Test results revealed that concentration and flow rate of absorbent are positive correlations with CO2 absorption whereas temperature and flow rate of gas are negative correlations with CO2 absorption. Experimental results demonstrate CO2 in biogas can be removed in biogas with Ca(OH)2 as absorbent with the highest absorption is 91.17 % by 1.75 gram/L of CaO