REV.CHIM.(Bucharest)♦68♦No. 12 ♦2017 http://www.revistadechimie.ro 2771 Determination of Physicochemical Properties and Emissions for Different Blends of Biodiesel from Watermelon (Citrullus lanatus L.) Seeds and Diesel Fuel MIHAELA GABRIELA DUMITRU 1 *, DELIA NICA BADEA 2 , DRAGOS TUTUNEA 3 1 University of Craiova, Faculty of Science, Department of Chemistry, Calea Bucuresti 107i, 200585,Craiova, Romania 2 Constantin Brancusi University of Targu Jiu, Faculty of Technical Medical and Behavioural Sciences,1 Republicii Blvd., 210152, Targu, Jiu, Romania 3 University of Craiova, Faculty of Mechanics, Calea Bucuresti, 107i, 200585, Craiova, Romania Across the world the fossil fuels are depleting and countries are forced to find an alternative source to reduce green house gases and replace petroleum fuels. Depending of the raw material sources, vegetable oils, animal fats or algae, biodiesel offers a solution for a clean-burning diesel fuel. Watermelon (Citrullus lanatus L.) seed were collected and the oil was extracted. The oil was transformed into fatty acid methyl esters through a transesterification process and blended in various proportions with diesel fuel. The physico- chemical properties of fuels were determined. Results obtained showed that the biodiesel has a density (0.870 g/cm 3 ), kinematic viscosity 40°C (3.1 mm 2 /s), flash point (128°C), saponification index (150 mgKOH/ g), iodine index (108 mgI 2 /100g), peroxide index (3.7 mEqO 2 /Kg) and oxidation stability (6 hours) in the range of UE specifications. The engine tests were conducted on a Deutz F4L912 diesel engine, 51 kW, 4- stroke, air cooled, direct injection diesel engine. From the test performed was observed that the CO and HC emissions were reduced due to high content of oxygen in biodiesel blends. Keywords: Citrullus lanatus L., seeds, biodiesel, emissions During last decades the environmental impacts of fossil fuels on climate change have led to increase usage of alternative fuels. Numerous studies are undergoing to find a potential replacement for petroleum fuels either using biodiesel or bioethanol [1,2]. Biodiesel is defined as a fuel composed of mixture of fatty acid alkyl esters obtained by a transesterification process from vegetable oils or animal fats [3]. In July 2017 the biodiesel production in U.S. was 149 million gallons with an increase of 9 million gallons higher than June 2017 with 63 million gallons sold as B100 and 87 million gallons sold as blends with petrodiesel fuels [4]. Researchers are focused in obtaining the biofuel from various vegetable oils like soybean, palm, jatropha, sunûower, linseed, cotton, rape, mustard, neem, peanut, etc. The main drawback of biodiesel production is the high cost of the raw material and limited availability especially of the alimentary oils [5]. Using biodiesel in internal combustion engines can reduce considerably hydrocarbons (HC), carbon monoxide (CO) and smoke and increase NOx emission due to the higher content of oxygen. Another drawback of biodiesel is higher viscosity, lower volatility and higher molecular weight which can cause poor atomization and incomplete combustion [6]. Watermelon ( Citrullus lanatus ) is a member of the Cucurbitaceae family, known as gourd family (include cucumbers, pumpkins and other melons). Citrullus lanatus is a popular species cultivated in the summer in S-V region of Romania [7]. The seeds are often discarded or in others countries used as animal feed or snack food [8]. The seeds have a high percent of oil predominant in lenoleic, oleic, palmitic, and stearic acids and minor constituents as palmitoleic, myristic and linolenic acids [9]. Praveen A. [10] studied the effects of adding blends of watermelon biodiesel on the performance and emission characteristics on a kirloskar single cylinder diesel engine 5.2 kW, 4-stroke with eddy current dynamometer. The results showed a reduction in the Brake Thermal Efficiency and in the total fuel consumption for all biodiesel blends compared with petrodiesel fuel. B20 blend gave the best performance in the emissions of Hydrocarbons and Carbon Monoxide. The emissions of Nitrogen Oxide were higher for all biodiesel blends (B20, B40, B60, B80 and B100). Soundarrajan et al. [11] used a single cylinder water cooled diesel engine to investigate the emissions and performance of watermelon biodiesel blends (B25, B50, B75, and B100) as alternative fuel. The emissions of CO, HC and smoke opacity of biodiesel blends were less than petrodiesel. The NOx emissions for B75 blend were slightly more than normal diesel fuel. Panneerselvam et al. [12] reported for various watermelon biodiesel blends an increase in the brake- specific fuel consumption and a decrease in the brake thermal efficiency. Emissions were reduced for carbon monoxide and hydrocarbons with slight increase in the while the oxides of nitrogen and smoke. Also the cylinder pressure and heat release rate decreased at higher biodiesel blends. In this present work watermelon seeds which normally are discarded were used to produce biodiesel and to investigate emissions for various blends of biodiesel/ petrodiesel. Experimental part Materials and methods W ater melon (Citr ullus lanatus) sedes The seeds were obtained from twelve batches of certified watermelon (Citrullus lanatus) purchased from Craiova market during summer in 2017. The selecting process was done randomly. The watermelons (Citrullus lanatus) were cut and the seeds were collected and washed with water. Oil from watermelon (Citrullus lanatus) sedes The extraction of oil from watermelon seeds was carried out in a Soxhlet-type device using light petroleum solvent. The extraction time was 6 h. After oil extraction, the excess * email: dummgs@yahoo.com