Quality enhancement of biogas produced by domestically operated biogas plants in Sri Lanka

Abstract

At present there is an energy crisis around the world. The energy consumption as well as its demand rapidly increasing every day. As a solution for this escalating energy demand and prices with environmental impact, people have already started to switch into renewable energy sources. Biogas is one of renewable energy source that can be generated using domestic food waste as well as municipal waste which has been a hazard for the day-to-day life of the people.. Especially for domestic purposes, it has been a challenging solution for LPG and a good solution for the areas where there is a scarcity of firewood. The problem with biogas is the emission of Hydrogen Sulfide (H2S) unburnt Methane (CH4). In commercial and industrial practices, biogas digesters that generate biogas are built to collect sewerage from the apartments, commercial buildings, or industries for the treatments. The gas produced from the waste has a considerable amount of H2S which has a bad odor when the biogas emitted to the atmosphere, hence people will not be willing to use it as a fuel. As well as the presence of H2S and CO2 in the biogas has detrimental effects on health, corrosion of the components, and lowering the calorific value. This research focuses on the quality enhancement of biogas produced by domestically operated biogas plants in Sri Lanka targeting domestic, commercial, and industrial biogas plants that can be easily operated by using municipal wastes, industrial sewerage, and cattle dung. Basically, the biogas cleaning system developed here (purifying unit) has separation units of carbon dioxide, hydrogen sulfide, and water vapor. Calcium Hydroxide Pellets and Activated Carbon are used to remove CO2 when Ferric Oxide pellets remove Hydrogen Sulfide. Silica Gel is used to remove water vapor. Finally, the quality of gas that sending through this purifying systems was tested. According to the test results, a fine-tuning process was carried out to optimize the gas properties and relative composition of the gases.