Waste fish oil biodiesel as a source of renewable fuel in Iran

Among the renewable energy sources, the potential for biofuel energy in Iran is numerous. The Iranian government is paying considerable attention for utilization of renewable energy; especially biofuels. During recent years, fish wastes are considered as loss. Biodiesel production, manure composting, biogas production and burning of fish wastes to produce energy are different ways to utilize the fish waste in the world. Increasing demand for fissile fuels in the world, reduced fossil fuel's resources and pollution problems are the causes to introduce alternative renewable resources. Extracted oil from wastes of aquatic resources is an example of raw materials for production of biodiesel in the world. This study presents a brief introduction to the resource, status and prospect of waste fish oil as a sustainable energy source for biodiesel production in Iran. The main advantages of using waste fish oil for biodiesel production in Iran is also described. In this study, design and manufacturing of an oil extraction machine is also introduced. The fish oil was separated from fish wastes with the help of the designed oil extraction machine. Experiments showed that 53% of fish wastes was in liquid phase (mixture of water, oil and suspended solids) and the extracted oil was about 11% of the total weight of the fish wastes (using of 7 kg of wastes, about 3.71 kg liquid was extracted and 0.8 l (768 g) oil was isolated). Biodiesel fuel was then produced from the extracted fish oil after the chemical reaction (transesterification, reaction between methanol, potassium hydroxide and oil from fish waste). In the present investigation, for each liter of produced fish oil, 0.9 l biodiesel was produced. Important fatty acids like palmeitoleic, palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid were identified for the extracted oil. The highest fatty acid ratio belonged oleic acid. These fatty acids affect the magnitude of the cetane number of biodiesel fuel. (C) 2012 Elsevier Ltd. All rights reserved.