Performance Evaluation of Fixed dome and Floating type Biogas Digesters for Tubewell Operation with Dual Fuel Approach in Pakistan

The idea of biogas as a diesel fuel substitute is not new. It is a very attractive alternative, especially in countries rich in agricultural products and poor in petroleum resources. It can be concluded from the study that while running a diesel engine in dual fuel mode i-e on diesel and biogas saved almost 62% to 64% diesel fuel, and consequently showing an annual saving of Rs. 3486/m3 and 3379/m3 capacity when run on dual fuel mode with respect to gas produced from fixed dome and floating drum biogas digesters respectively. The less saving in floating type biogas digester is due to gas losses from plant as compare to fixed dome biogas digester where system is air tight. Fixed dome biogas digester not only save the money but also the environment. Running engine through floating type biogas digester consumed 6.35% more diesel than fixed dome biogas digester in dual fuel mode. A 16 hp dual fuel diesel engine pumped 14 % more water from fixed dome biogas plant as compared floating drum biogas plant. It is therefore recommended that fixed dome biogas digester may be installed in such agroecological zones like Islamabad.