DEVELOPMENT AND HEAT TRANSFER SIMULATION OF EPOXIDIZED JATROPHA BIOLUBRICANT FOR SPARK IGNITION ENGINES

ABSTRACT

Vegetable oils need to be chemically modified before being used for biolubricant production for internal combustion engines applications. One of the most effective chemical modifications for vegetable oils is epoxidation of its double bonds. In this work, Crude Jatropha oil (CJO) was epoxidized using peracid generated in-situ by the reaction of formic acid and hydrogen peroxide using sulfuric acid as catalyst. FTIR and Iodine Value were used to confirm the formation of epoxides. Epoxidized Jatropha biolube (EJBL) was produced by two stage transesterification; the first is aimed at producing an intermediate product-methyl ester of the jatropha oil, while the second uses the methyl ester as a reactant to produce a polyol ester (biolubricant) using Trimethylolpropane (TMP). The EJBL was blended with B023232/B023333 additive from 1 % to 10 % by volume with 1 % increments. The physico-chemical properties of the blends were determined and the blend whose physico-chemical properties are close to that of reference oil was chosen for the engine test. A TecQuipment TD201 small engine test set located at the heat engine laboratory of Mechanical Engineering Department Ahmadu Bello University, Zaria, was used for engine performance test. The Equipment manufacturer specified that SAE30 or 10W30 engine oil should be used on the engine. The epoxidation process has improved the thermal and oxidative stabilities of the jatropha oil from 76oC to 130oC. The physico-chemical analyses of the EJBL and its blends show that EJBLO5 is close to SAE 30. It was observed that EJBL05 is better than SAE 30 in Viscosity Index, Flash Point, Pour Point, Evaporation Loss, Specific Heat Capacity, Coefficient of thermal Conductivity and demulsibility. The torque developed by the test engine (TecQuipment TD 201 ) within the test range used ( 0- 3450 rev min-1) for EJBL05 were 0 – 9.9 Nm  and for SAE 30 ( reference engine oil ), 0 – 9.4 Nm; Similarly the engine Brake Powers for EJBL05 were 0 – 3577 W and for SAE30, 0 – 3396 W; The Brake Mean Effective Pressures ( BMEP ) for EJBL05 were 0 – 6.22 bar and for SAE 30, 0 - 5.99 bar. The Brake Specific Fuel Consumptions (BSFC) for EJBL05 were 0 – 0.3492 kg kWh-1 and for SAE30, 0 – 0.3762 kg kWh-1. The simulated results obtained for oil temperatures, engine outer surface temperatures and exhaust valve temperatures were close to the experimented results with R2 value of 0.988, 0.969 and 0.977 respectively; signifying that the simulation was valid.