Study On Preparation Of Biodiesel With Pistacia Chinensis

Biodiesel is a potential substitute of conventional fossil diesel and has many advantages such as renewable, environment-friendly, high cetane number and excellent combustion behavior. Using food-grade vegetable oils as feedstock for biodiesel production is not economically feasible, since the biodiesel from edible oils is more expensive than diesel fuel. Therefore, researches on alternative non-edible and cheaper feedstock for biodiesel production have been receiving more attention all over the world, especially in China. In the present study, the feedstock selected is Pistacia Chinensis seed oil from Handan, Hebei province. The paper mainly focused on transesterification of Pistacia Chinensis seed oil with methanol under the catalysis of alkaline, and the instrumental analyses of the product biodiesel were carried out.The acid value of Pistacia Chinensis seed oil was 33.40 mgKOH/g. When an alkaline catalyst is used in transesterification, acid value of oil should be reduced to less than 1.5 mgKOH/g. There are seldom reports about deacidification of Pistacia Chinensis seed oil. Thus, we designed a simple, fast and effective method to reduce acid value of crude oil. Pistacia chinensis seed oil was deacidified by extracting with ethanol. The results showed that the optimum conditions were as follows: the ratio of ethanol to oil was 3∶1, extraction temperature was 30℃and extracting times were three. Under these conditions, the acid value of Pistacia Chinensis crude oil has been successfully reduced to 0.23 mgKOH/g. Therefore, deacidification of oils by liquid-liquid extraction is a simple and low operation cost method. It is a promising deacidification process which can be used in industry.Single factor experiments were conducted to test the factors which influence the yield of biodiesel. It was indicated that the optimum conditions for the transesterification reaction were as follows: the molar ratio of methanol and Pistacia Chinensis seed oil was six to one; catalyst dose was 1.0 wt%; the reaction time was 60 minutes and the reaction temperature was about 65℃. The yield of biodiesel was as high as 96.40% under the optimum conditions. Besides, we prepared heterogeneous alkaline catalysts. The prepared catalysts were characterized by XRD and used tentatively to catalyze the transesterification reaction.This paper applied the linear regression to verify the accuracy of the density method and kinematic viscosity, which may be used to calculated the conversion percentage of transesterification. The Pistacia Chinensis seed oil and biodiesel were analyzed by FT-IR. It was found that the absorptions range from 1000cm^-1 to 1500cm^-1 were significantly different. The absorption peaks at 1245cm^-1, 1196cm^-1 and 1171cm^-1 were attributed to the stretching vibration from O-CH₃ in FAME and that at 1436cm^-1 was attributed to the asymmetric bending vibration from C-H of O-CH₃. These data can conveniently testify that the transesterification happened between seed oil of Pistacia Chinensis and methanol. The main components of biodiesel of Pistacia Chinensis have been determined by GC, GC-MS and HPLC. The results showed that the main components of biodiesel of Pistacia Chinensis were methyl palmitate(21.05%), methyl linoleate(36.59%), methyl oleate(41.35%) and methyl stearate(1.01%). According to the experimental data, Pistacia Chinensis seed oil can be employed as a more suitable feedstock to produce biodiesel.