INVESTIGATIONS ON ABSORPTION TECHNIQUE FOR BIOGAS PURIFICATION

Abstract

In this research, a biogas purification system was developed using Sodium Hydroxide and Calcium Hydroxide solution through bubble column absorption tower made from plastic bottle. Biogas from 3 different digesters (D1, D2, and D3) with varying feeds were used, and the experiment was conducted with 5 types of solution- pure water, Sodium hydroxide 0.625 mol, Sodium hydroxide 0.9375 mol, Calcium hydroxide 0.625 mol, and Calcium hydroxide 0.9375 mol, with a constant volume of 400 ml for each run. The biogas flow rate was set at 1.25 l/min and 3.33 l/min, and the biogas composition was measured before and after purification using Gas Analyzer. The research findings demonstrated that the effectiveness of the purification system was affected by the biogas flow rate, the type of solution used, and its concentration. Moreover, the results showed that the higher the absorbent in the bubble column, the higher the percentage of C02 absorption and CH4 content. The most efficient solution for biogas purification was Sodium Hydroxide 0.9375 mol, which can give a maximum methane ratio of 86.2% at a flow rate of biogas of 1.25 l/min. This paper gives a software analysis of the interaction of absorbent and gas molecules in the absorption column and its effect on the outlet gas temperature. DWSIM software was used to study the model. The research findings demonstrated that the interaction between the molecules was affected by the gas flow rate, the absorbent flow rate and the absorbent pressure.