Analysis of Flue Gas Emissions Using a Semi-industrial Boiler Fueled by Biodiesel Produced from Two-stage Transesterification of Waste Cooking Oil

M. Mansourpoor and A. Shariati

Abstract
In this work, waste cooking oil and methanol as feedstock together with sulfuric acid and potassium hydroxide as catalysts were used to produce biodiesel. The physical properties of the waste cooking oil, the produced biodiesel and the purchased petrodiesel were measured using specified ASTM standards. To examine their performance and their flue gases emissions, biodiesel and petrodiesel were burnt in a wet base semi-industrial boiler. The emitted combustion gases, including CO, NOx, SO2 and CO2, were measured with a flue-gas analyzer at a wide range of air-to-fuel ratios and two levels of energy. For better reliability, all tests were repeated five times and almost no measurable differences were found in the repeat tests. The results show that produced biodiesel meets ASTM standards for flash point, heating value, specific gravity, kinematic viscosity, copper corrosion, acid number, cetane number, carbon residue, and total sulfur. These properties of biodiesel are also comparable with the petrodiesel properties. The trends of exhaust temperature and combustion efficiency of biodiesel are the same as petrodiesel at different air-to-fuel ratio. However, they are slightly lower. The CO, NOx, SO2 and CO2 emissions of biodiesel are lower than those of petrodiesel at different air-to-fuel ratios and two levels of energy.

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Keywords
biodiesel, combustion efficiency, emission, renewable energy, waste cooking oil