Mathematical optimisation of biogas production and utilisation

Abstract

Palm oil mill effluent (POME) is a source of biogas generation that can be a substitute for fossil fuel. High content of biological oxygen demand (BOD) and chemical oxygen demand (COD) of POME has the advantage to produce large amount of biogas through anaerobic digestion. The purpose of this research is to develop a mathematical model to determine the optimal process pathway of biogas, covering from the purification technology to mode of transportation and utilization. A hypothetical case study is conducted to run and test the model, in which different target location with different utilization mode was chosen. The model chose membrane separation of biogas, pipeline transportation to the targeted site, and electricity generation as the optimal pathway for biogas processing and utilization. Sensitivity analysis is performed to determine the impact of product price on the biogas process pathway selection. The sensitivity analysis revealed that the price of Bio-CNG has an impact on the model. Sensitivity analysis suggested the Bio-CNG sales price should be at least 10.4 USD/GJ to be economically feasible.