Biogas Purification by CO 2 Reduction in Bubble Column Using Ca(OH) 2 and NaOH

Abstract

This study is about biogas purification process by reducing the CO2 content in order to increase the heating value of biogas by using Ca(OH)2 and NaOH solution as the absorbent in a bubble column. The purpose of this study is to determine the effect of the sparger hole diameter and the height of Ca(OH)2 and NaOH solutions in the column. The bubble column is made from acrylic with diameter of (2.5; 3.0; and 4.0 in) and the height of column is 100 cm. The column is equipped with a sparger with a variety of hole diameter about 1 and 2 mm. The sparger is placed at the bottom of the column. The volume of solution for each run is same (2 liters) but the height of solvent is followed the diameter of the columns. Therefore, the height of the solutions is 63, 44, and 25 cm. The flow rate of the biogas is 1 liter/min, which was fed from the bottom of the column. Both output and input in each run sample were analyzed by Gas Chromatography 2014 AT (SHIMADZU Corp 08128). The results show that the higher the absorbent in the bubble column, the higher the percentage of CO2 absorption and the CH4 contain. The absorption of the CO2 is varied using Ca(OH)2 and using NaOH. The absorption using Ca(OH)2 and NaOH are 70.18 and 90.66% respectively. The CH4 content also increases using Ca(OH)2 and NaOH up to 66.84 and 87.755% respectively.