Effects of Biogas Plants on Environment

1. Bio-CNG: An Alternative to Fossil Fuels Growing consumption of fossil fuels and the environmental damage caused by them has led to increased use of compressed natural gas (CNG) in the transportation sector. CNG is a clean fuel and, is promoted worldwide over conventional gasoline and diesel fuels. CNG has many advantages over conventional fuels, such as lower corrosion and wear to the engine, environmentally friendlier because of lower emissions of carbon and particulate matter per equivalent distance traveled. Also, it is lighter than air, making it safer in the case of a leak. But CNG, which is basically compressed natural gas, is also very limited and its reserves are getting exhausted at a rapid pace.

2. Biogas is a renewable source of energy and has become a potential alternative to fossil fuels with the building of a number of Biogas plants in India. Purified or enriched biogas also called bio-CNG, is the best alternative to compressed natural gas. Calorific value is the parameter used to judge the efficiency of fuel. The average calorific value of biogas is lower than that of CNG. The difference in calorific values is mainly due to the incombustible part of biogas. Some contaminants in biogas can also damage the engine. These harmful effects of the impurities found in the raw biogas make biogas upgrading an essential requirement. The process of biogasupgradation generates new possibilities for its applicability at a larger scale as then it can be used as a substitute for natural gas. Biogas Upgrading There are a number of technologies to enrich biogas such as absorption, pressure swing adsorption, membrane separation, water scrubbing, and cryogenic separation. These enrichment methods increase the level of methane in the biogas as well as remove the impurities which affect the calorific value of the gas. Pressure Swing Adsorption is the most successful biogas upgrading method in terms of cost, efficiency and longevity. But, the ideal technology can differ from case to case and is decided by various factors such as quantity of biogas generation, desired quality of biogas, site of application, and economics of the process. Biogas contains three main impurities, namely carbon dioxide, water vapor and hydrogen sulfide and a few other impurities, depending on the type of substrate used for biogas generation. Biogas upgradation is a three-step process, starting from cleaning, drying and finally refining of the raw biogas. The first step is cleaning, which removes the H2S content, the second step is drying which removes the H20 and the final step is refining which removes the Carbon dioxide. All these steps are essential for biogas upgrading, which helps in increasing the calorific value of the final upgraded gas. Contact Details: Visit the website: http://www.biogaspurifier.com