Optimization of Process Parameters for Production of Linseed Bio-fuel and Performance Investigation of Diesel Engine Fuelled with Linseed Biodiesel

Abstract

Biodiesel is receiving increased attention as an alternative, biodegradable, non-toxic and renewable diesel fuel. It is produced from vegetable oils and animal fats by using transesterification reaction. Due to continuous depletion of fossil fuels the global prices of crude petroleum are hiked considerably which is bound to affect the economy of many countries. In country like India, where edible oils are imported it would be worthwhile to explore the possibility of using non edible oils for biodiesel production. It will also help to avoid the fuel versus food conflict. Therefore in the present study, linseed oil has been chosen for biodiesel production. In this work optimization of parameters, such as molar ratio, catalyst concentration, catalyst type, reaction temperature and reaction time, controlling the production yield of linseed oil methyl ester was achieved. A large number of experiments were required to optimize the process parameters of linseed biodiesel production by full factorial design. So, Taguchi approach of orthogonal arrays (L18) was used to design the experiments and perform optimization by considering fewest experiments. Only 18 experiments were performed which were equivalent to 243 experimental situations. The optimal combination of controlling parameters was found to be 1.5% catalyst concentration by weight, 60˚C reaction temperature, 60 minutes reaction time and by the use of KOH as catalyst. Theoretically 93.13% production yield of biodiesel was expected by using optimum conditions. By producing linseed oil methyl ester by optimal combination of experimental conditions obtained from Taguchi method 98.4% yield was achieved which was more than the expected yield. Statistical technique ANOVA (analysis of variance) was used to study the influence of different parameters on biodiesel production yield. Among all the parameters catalyst concentration was found to be most dominating with 31.86% contribution, followed by catalyst type with 24.95% contribution. Molar ratio and reaction time were found to be least significant parameters with only 1.99% and 20.32% contributions respectively for transesterification of linseed oil. The fuel properties of optimally produced linseed biodiesel were observed to be comparable to that of pure diesel and were also conforming to latest biodiesel standards. The various performance and emission parameters like brake mean effective pressure (BMEP), brake power (BP), brake specific fuel consumption(BSFC), mechanical efficiency (Mech. Eff.), brake thermal efficiency (BthEff), CO emissions, CO2 emissions, HC emissions, NOX emissions were evaluated at different loads and compression ratios in a 4 stroke, single cylinder variable compression ratio engine. These performance and emission parameters of diesel fuel were compared with that of B10, B20, and B30.The performance parameters of B10 blend were observed to be nearly similar to that of pure diesel fuel at all load conditions. B10 blend showed better performance parameters than all other blends of biodiesel. At higher compression ratios the performance of engine was observed to be better. The brake specific fuel consumption of engine was lowest for B10 blend among all the blends. The different emissions parameters of engine such as CO, CO2, and HC were observed to be nearly similar to the diesel fuel for B10 blend. With increase in amount of blend these emissions were decreased. Among all the blends, these emissions were found to be lowest for B30 blend while the NOX emissions were found to be lowest for B10 blend among all three blends. The CO and HC emissions were observed to be decreased at higher compression ratios while NOX and CO2 emissions were increased for higher compression ratios.