engleski

Membrane filtration as an environmentally friendly method for crude biodiesel purification

Biodiesel is the first alternative fuel which physico-chemical properties are regulated by appropriate standards: American ASTM D 6751 and European standard EN 14214. The process of biodiesel production consists of four main phases: 1) preparation of feedstock, 2) transesterification, 3) phase separation, and 4) processing of the reaction product - purification of crude biodiesel to meet the specification provided by EN 14214. The purification process of crude biodiesel is usually carried out by two notable techniques: wet and dry washing. The most commonly used is wet process. A major drawback in the use of water in purification process is the generation of large amount of wastewater that greatly increases the biodiesel production costs followed by drying of the product, which requires additional amount of energy and time. The greatest lack of dry washing using different ion-exchange resins is the inability to remove glycerol and methanol from crude biodiesel to the limits prescribed by EN 14214 as well as the disposal problem of spent ion-exchange resins. Because of aforementioned, the use of membrane technology in the process of biodiesel purification has appeared as an alternative for the existing purification techniques. The membrane filtration is environmentally friendly and, in comparison with other two methods for biodiesel purification, requires less energy. Ultra- and/or nano- membrane filtration of biodiesel has so far provided the very good results. By membrane filtration, glycerol, methanol and water content in biodiesel can be decreased to the amounts prescribed by the standards. In frame of this work the short overview of the possibility to use the ultra- and/or nano- filtration in purification process of biodiesel will be presented.

biodiesel ; purification ; membrane filtration ; glicerol ; methanol

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