Process Research Of Biodiesel From Waste Oil And Fat

Energy crisis has been becoming aggravating because of the petroleum shortage. Biodiesel, a kind of environmental-friendly green energy, is becoming one of the hot topic for its characteristic of clean and renewable. However, the pivotal factor of restricting the extension and application of biodiesel is oil and fat resourse.Fatty acid methyl ester, a kind of organic raw material with wide application, is the main components of biodiesel. In this article, three representative oil and fat resourse (edible raw oil, unedible linseed oil and waste oil and fat) were used to study the fatty acid methyl ester preparation technology, and the products from different technologies were compared and analysed. For plant oil, ester exchange process was performed immediately after simple decolorating and alkali refining pretreatment. For waste oils and fats, since the serious component deterioration, pretreatment become more complicated. Two technologies of preesterification-ester exchange and saponification -esterification were adapted for this condition.This article emphasizes on studying the technology conditions of oil and fat decoloration pretreatment and ester exchange process. Activated bleaching-earth was used as adsorbent in decoloration process for its powerful adsorptive charactersitic. Experiments confirmed the best technology condition at atmospheric pressure as decolorationtemperature 85℃, decolorationtime 90mim and bleaching-earth dosage 5%. The paper emphasizes on the preparation of fatty acid methyl-ester (FAME) by oil and fat and methanol. In this part, we analyzed the condition of pre-esterification and esterification, and found out the best method. The optimum conditions were obtained for the transesterification: molar ratio of methanol to oil 6:1, usage amount of NaOH 1%, reaction temperature 65℃, reaction time 3 hours.Physicochemical propertics of obtained biodiesel were measured. Qualitative and quantitative analysises were performed by GC-MS. Except for measuring the yields and comparing the experimental conditions, the article also confirmed the accurate composition of product biodiesel, and results indicated that the biodiesel made by oil and fat mainly consists of Oleicacid methyl ester, Linoleic acid methyl ester, Hexadecanoic acid methyl ester, Octadecanoic acid methyl ester and some other acid methyl ester.Research of biodiesel preparation technologies with different oil and fat raw materials can provide a wider space for developing biodiesel. Using unedible and waste oils and fats to produce biodiesel not only help to alleviate the raw material problem of biodiesel preparation, but also help solve environmental problems. In additon, it has great application potential in reducing the cost of biodiesel.