Performance Analysis and Modification of Portable Biogas Plant

Abstract

Biogas technology has come a long way in Nepal since its introduction in 1955. The government started the biogas program in 1975 while the Biogas Support Program (BSP) established in 1992 contributed, to the popularization of use of biogas. Biogas is highly efficient, low carbon emitting renewable energy fuel and it can substitute both traditional biomass and liquid petroleum gas (LPG) for cooking and heating purposes. However, replication of the technology is still relatively low. Only 17% of all potential households make use of it. While the usage of LPG is steadily rising, a sizable portion of the population still relies on the use of solid biomass. In the development of the biogas market, Nepal has been introduced with different types of biogas plants. The most popular of it is the GGC model while a recent type of plant made of Fiber Reinforced Plastic has been introduced. The plant is basically a comparatively portable kind of tank especially designed for urban domestic use. This study tries to investigate the performance of the Portable FRP Biogas plant and compare it with existing GGC2047 model. The test was performed with three conditions of feeding normal, with physical pretreatment and with greenhouse. With feedstocks mostly being food waste from households, the results show that biogas production is still possible. The plant when fed exclusively with organic waste produced maximum of 0.257 m3 of biogas which had a maximum of 43% of methane content. The pH level dropped while feeding only organic waste for a month. The TS reduction in feedstock to digestate was upto 85% and VS reduction was upto 90%. The plant has a potential to displace 3.67kg of LPG per month