Variations of cetane number of jatropha biodiesel blends with mineral diesel

Cetane number(CN)-a prime indicator of diesel fuel quality,is a quantity indicating the combustion behaviour of diesel fuel and compression required for ignition in diesel engines.This study examines the determination of CN of Jatropha biodiesel blends with mineral diesel using their physical properties,and their variations of CN with percentage composition of Jatropha biodiesel in the blends.Jatropha biodiesel,converted through a transesterification process of its oil,is obtained and blended with diesel to obtain blend B10(10%biodiesel and 90%diesel)on a volumetric basis,at 25℃ ambient temperature and the same basis was employed for blends B20,B30,B40 and B50.The specific gravity and mid-distillation characteristic were obtained using a hydrometer and distillation curve apparatus based on ASTM D1298 and D86 standards respectively.The CN of Jatropha oil,its biodiesel and Jatropha biodiesel blends with diesel were analytically determined,employing the empirical relationship between measured physical properties of a two-variable cetane index equation.The results show that the CN of the Jatropha biodiesel increases significantly(about 29%)after transesterification compared with that of the Jatropha oil.Moreover,the specific gravity and CN of the blends increase with the percentage composition of Jatropha biodiesel in the blends.The CN of Jatropha biodiesel is 44.10,which is 8.7%higher than that of mineral diesel(40.62).It can be implied from the research outcomes that blending Jatropha biodiesel with diesel increases the CN of the blends,thus,could be used as cetane point(number)enhancer.

Investigation of extracted Sclerocarya birrea seed oil as a bioenergy resource for compression ignition engines

Sclerocarya birrea(Marula)seed oil was extracted and characterized for its physico-chemical properties and fatty acid compositions,respectively,by using standardized laboratory methods of the Association of Official and Analytical Chemist(AOAC).The fuel and lubrication properties of marula oil were also determined by using the ASTM methods,and the oil was evaluated in terms of its antiwear,viscometrics,volatility,stability,environmental compatibility properties and energy content.It was found that the high percentage of mono-unsaturated oleic acid(73.6%)provided the oiliness that makes marula oil a natural alternative to genetically modify high oleic acid sunflower oil used in biodiesel production.The aggregate properties of seed oiliness as exemplified by the high oleic acid content,high saponification value(178.6 mg/KOH)and viscosity(41 mm2/s)makes marula oil to be prospective based oil for engine crank case biolubricants with antiwear and friction reduction properties.However,the higher oil viscosity exhibited by marula seed oil in comparison to diesel could pose some durability problems to compression ignition engines,when used directly as fuel.Nonetheless,the reduction of oil viscosity would be required by heating,blending with diesel fuel,or by transesterification to forestall the risk of engine failure resulting from the use of unmodified marula oil.The flash point of marula oil(235℃)is somewhat close to that of monograde SAE 40 mineral oil(240℃),and appreciably higher than that of diesel fuel(52℃).The high flash point makes the seed oil less flammable and ensures safer handling and transportation.While,the low pour point(-13.7℃)ensures the oil usability for engines at cold start and under low load conditions.The oxidation stability of marula oil is ascribed to the traces of natural antioxidants presented in the oil and improves the oil’s shelf life,notwithstanding the high peroxide value(4.58 mequiv/kg),and linolenic acid content(0.3%),which ought to have been the culprit for lipolytic hydrolysis and rancidity.Furthermore,marula seed oil is more biodegradable and environmentally friendly than oils derived from petroleum crude.The closely related cetane number(47.8)and heating values(38.2 mJ/kg)of marula oil to diesel fuel would undeniably sustain the combustion efficiency of diesel fuel and also supply a comparable engine performance output in compression ignition engines.The candidacy of marula seed oil,as a bioenergy resource for alternative fuel,fuel additives and lubricants,will no doubt expand the energy supply mix,conserve fossil fuel reserves and mitigate environmental contamination.