Investigating the effects of different alcohol additives in biodiesel-diesel fuel blends on performance, combustion and emission characteristics of the diesel engines

In this study, the parameters which are alcohol/oil molar ratio, catalyst concentration, reaction temperature and reaction time affecting biodiesel production from yellow mustard (Sinapis alba L.) seed crude oil by transesterification process have been optimized using response surface methodology. The biodiesel which was produced from the maximum biodiesel yield obtained reaction conditions was blended with diesel and different alcohols (methanol, ethanol, isopropanol, butanol, pentanol). However, the experiments could not be realized because homogeneity of methanol addition in test fuel has not been ensured. The physical, chemical and fuel properties of other fuels were measured. Furthermore, the corrosion characteristics of different metals (aluminium, copper, zinc, brass) which were put in the fuels have been determined by static immersion test. Also, the experimental results obtained concerning engine performances, combustion analysis, exhaust emissions, energy and exergy balances of a diesel engine fueled with these fuels compared with diesel fuel in laboratory tests. As a result, the optimum biodiesel yield was obtained to be 96.695% at 7.407:1 methanol/oil molar ratio, 0.627% catalyst concentration, 61.837oC reaction temperature and 62.122 min reaction time. In corrosion experiments depending on the increase of immersion time corrosion rate of metals decreased, copper is the most corrosion suffered, and brass, zinc and aluminum followed by copper, respectively. In the result of engine tests, values of the effective engine torque and the effective engine power from fuel blends were lower than diesel fuel as average 12.31%, and values of the effective specific fuel consumption from fuel blends were higher than diesel fuel as average 9.91%. The results of combustion analysis of fuel blends were similarly the results of diesel fuel. Besides, exhaust gas temperature, smoke opacity, CO, CO2 and NOX emissions were decresed and O2 emissions were increased with addition of alcohol. The energy and exergy analysis of test fuels have been realized at 1400 1/min which was obtained the maximum effective engine torque and at 2600 1/min which was obtained the maximum effective engine power. The energy efficiency was calculated as 29.82-32.12% and the exergy efficiency was calculated as 27.94-29.94% at 1400 1/min, the energy efficiency was calculated as 30.51-32.85% and the exergy efficiency was calculated as 28.60-30.62% at 2600 1/min. Keywords: Yellow mustard oil, optimization, alcohol, corrosion, engine performance, combustion analysis, exhaust emissions, energy, exergy