Bioethanol production from sago palm waste as an alternative fuel for automotive engines

Abstract

The increasing demands of petroleum fuels, together with the environmental pollution issues, have motivated the efforts on discovering new alternative fuels. Bioethanol produced from biomass is considered as one of the important alternatives for petroleum fuels. In Sarawak, wastes from sago factories are currently causing serious environment problems. These wastes can be used as favourable feedstock for bioethanol production. The purpose of this research is to produce bioethanol from sago palm waste, and study the effects of bioethanol on corrosion of materials, and performance and emissions of petrol engine. First, bioethanol was produced from sago pith waste (SPW) using microwave hydrothermal hydrolysis accelerated by CO2 (MHH) and microwave assisted acid hydrolysis (MAH). Bioethanol was also produced from sago bark waste (SBW) using microwave aided acid treatment and enzymatic hydrolysis (MAEH). Second, effect of bioethanol and gasoline blends on corrosion of materials was studied using static immersion test. Furthermore, corrosion of materials in biodiesel–diesel–ethanol (BDE) fuel blends was also studied. Finally, the effect of bioethanol on performance and emissions of petrol engine was studied. A maximum of 15.6 g and 30.8 g ethanol per 100 g dry SPW was produced using MHH and MAH, respectively. In addition, a maximum of 30.67 g ethanol was produced from 100 g dry SBW using MAEH. Corrosion of materials and degradation of fuel properties were 2.4 times higher in higher ethanol blends (above E25) compared to lower ethanol blends (up to E25). Corrosion and degradation of materials in BDE fuel blends was 1.7 times higher than petro-diesel. Petrol engine results showed that use of sago waste bioethanol (E25) significantly increased the engine power, torque, brake thermal efficiency, and mean effective pressure by about 4.5%, 4.3%, 9% and 4.2% compared to gasoline (E0), respectively. Emissions results showed a significant reduction in CO, NOx and HC emissions by about 42%, 7% and 5.2%, respectively for E25 compared to E0. This study acclaims that sago bioethanol is a feasible alternative to reduce the dependence on fossil fuels for the automotive industry.