%0 Journal Article %1 noauthororeditor %D 2017 %E IJIES, %J International Journal of Innovations in Engineering and Science %K myown %N 9 %P 16-23 %T Effect of Methane Concentration in Biogas on the Performance and Emission characteristics of an Otto Cycle Engine %U http://www.ijies.net/archives/vol-2-no-9 %V 2 %X In recent year, increased environmental awareness and energy shortages have encouraged researchers to investigate the possibility of using alternate fuels. The purpose of finding the alternate sources is to minimize the consumption of conventional fossil fuels and in turn to reduce the degradation of environmental quality to a great extent. The use of bio-based fuels like biogas produced from biomass or bio-wastes is a valuable energy source which is sustainable and can be manufactured from locally available waste streams thereby solving the problem of waste disposal. Local wastes (organic wastes) contain enough energy to contribute significantly to energy supply system especially in the rural regions of developing countries. Biogas is a clean and environment friendly fuel produced from anaerobic digestion of agro, animal or human wastes. The biogas has about 60% methane and 40% carbon dioxide with small traces of H2S. The large quantity of CO2 present in raw biogas however, lowers its calorific value, flame velocity and flammability limit. The presence of H2S leads to formation of SO2 which combines with the water vapour to form acids and hence corrode the metals. Thus, raw biogas as such cannot be recommended for powering vehicular I.C engine. In the present research work, an attempt has been made to upgrade the quality of raw biogas by lowering its CO2 and H2S content, thus enriching its methane content and to study the performance and emission characteristics of upgraded biogas fuelled four stroke Otto cycle engine as fuel. The influence of reduction in the concentration of CO2 in the biogas on the performance, emissions and combustion characteristics in a constant volume Otto cycle (SI) engine was studied experimentally. A low cost water scrubber was developed and used to lower CO2 levels from 40% in biogas to 20%. The tests covered the range of equivalence ratios (0.9 to 1.1) from rich mixture to lean operating limit operating in the range of 800-2400 rpm at compression ratio of 9.2:1. With reduction in the CO2 level, there was a significant improvement in the brake power, brake thermal efficiency and brake specific fuel consumption and also substantial reduction in exhaust emissions of hydrocarbons (HC), carbon monoxide (CO) and carbon dioxide (CO2). The lean limit of combustion also gets extended with the use of upgraded biogas in the engine. Faster heat release rates indicated enhanced combustion rates, which were mainly responsible for the improvement in thermal efficiency of the engine. However, there was increase in the NOx emission by 3% compared to raw biogas engine operation. To mitigate increase in NOx emission the spark timings were retarded by about 50 when CO2 concentration was decreased by 20%.

@article{noauthororeditor, abstract = {In recent year, increased environmental awareness and energy shortages have encouraged researchers to investigate the possibility of using alternate fuels. The purpose of finding the alternate sources is to minimize the consumption of conventional fossil fuels and in turn to reduce the degradation of environmental quality to a great extent. The use of bio-based fuels like biogas produced from biomass or bio-wastes is a valuable energy source which is sustainable and can be manufactured from locally available waste streams thereby solving the problem of waste disposal. Local wastes (organic wastes) contain enough energy to contribute significantly to energy supply system especially in the rural regions of developing countries. Biogas is a clean and environment friendly fuel produced from anaerobic digestion of agro, animal or human wastes. The biogas has about 60% methane and 40% carbon dioxide with small traces of H2S. The large quantity of CO2 present in raw biogas however, lowers its calorific value, flame velocity and flammability limit. The presence of H2S leads to formation of SO2 which combines with the water vapour to form acids and hence corrode the metals. Thus, raw biogas as such cannot be recommended for powering vehicular I.C engine. In the present research work, an attempt has been made to upgrade the quality of raw biogas by lowering its CO2 and H2S content, thus enriching its methane content and to study the performance and emission characteristics of upgraded biogas fuelled four stroke Otto cycle engine as fuel. The influence of reduction in the concentration of CO2 in the biogas on the performance, emissions and combustion characteristics in a constant volume Otto cycle (SI) engine was studied experimentally. A low cost water scrubber was developed and used to lower CO2 levels from 40% in biogas to 20%. The tests covered the range of equivalence ratios (0.9 to 1.1) from rich mixture to lean operating limit operating in the range of 800-2400 rpm at compression ratio of 9.2:1. With reduction in the CO2 level, there was a significant improvement in the brake power, brake thermal efficiency and brake specific fuel consumption and also substantial reduction in exhaust emissions of hydrocarbons (HC), carbon monoxide (CO) and carbon dioxide (CO2). The lean limit of combustion also gets extended with the use of upgraded biogas in the engine. Faster heat release rates indicated enhanced combustion rates, which were mainly responsible for the improvement in thermal efficiency of the engine. However, there was increase in the NOx emission by 3% compared to raw biogas engine operation. To mitigate increase in NOx emission the spark timings were retarded by about 50 when CO2 concentration was decreased by 20%.}, added-at = {2018-01-05T10:16:25.000+0100}, biburl = {https://www.bibsonomy.org/bibtex/237c383fd06b5e1cfbd9e5f47015eff80/journalijies}, editor = {IJIES}, interhash = {14300cace3097508f11a416567cb4c14}, intrahash = {37c383fd06b5e1cfbd9e5f47015eff80}, issn = {2456-3463}, journal = {International Journal of Innovations in Engineering and Science}, keywords = {myown}, language = {English}, month = {September}, number = 9, pages = {16-23}, timestamp = {2018-01-05T10:16:25.000+0100}, title = {Effect of Methane Concentration in Biogas on the Performance and Emission characteristics of an Otto Cycle Engine}, url = {http://www.ijies.net/archives/vol-2-no-9}, volume = 2, year = 2017 }