ORIGINAL PAPER Effect of FFA of Crude Rice Bran Oil on the Properties of Diesel Blends Subramani Saravanan Æ G. Nagarajan Æ G. Lakshmi Narayana Rao Received: 23 February 2008 / Revised: 30 April 2008 / Accepted: 2 May 2008 / Published online: 28 May 2008 Ó AOCS 2008 Abstract Crude rice bran oil (CRBO) with high free fatty acid (FFA) content is not suitable for eating purposes, however, it can be used as a fuel to partially replace or fully replace No.2 diesel. The main objective of the present work was to analyse the effect of FFA content of CRBO on the combustion properties such as viscosity, calorific value, volatility and aniline point. CRBO with different FFAs were collected and mixed with No.2 diesel to prepare CRBO-diesel blends. It was observed that the viscosity of the blends increased with increase in FFA while the calo- rific value decreased. Significant variations were observed in the distillation curve for the CRBO blends with different FFA. Aniline point of the blends was 10–15% lower than that of diesel and it is indirectly proportional to the FFA of CRBO in the blend. Experimental results showed that the combustion properties of CRBO are the function of the FFA in the oil. As a dilute blend with diesel, CRBO with high FFA content showed comparable combustion prop- erties to that of diesel. The properties differed in magnitude by 10–15% when compared with diesel. From the present investigation it is concluded that in blended form, CRBO with high FFA can be a potential resource to utilize it as an alternative fuel for CI (compression ignition) engines. Keywords Crude rice bran oil  FFA  Diesel blend  Combustion properties Introduction Increasing the availability of energy resources of their countries and meeting updated emission standards will be the biggest challenge over the next decade for researchers all over the world. As the petroleum resources are being depleted it is important to have renewable sources of energy with the potential for reduced environmental impact to achieve the above objectives. As compression ignition (CI) engines have gained significant and well-deserved attention for their wide range of applications in the energy sector, attention is focussed on determining an alternative fuel for CI engine fuel. Vegetable oils, a renewable mate- rial have the potential to replace petroleum diesel in their pure and modified form. Even though some neat vegetable oils have been tested in CI engines their higher viscosity restrict their direct use in the diesel engines combustion chamber [1]. To overcome this problem the vegetable oil chemical structure needs to be modified. This can be done by modification techniques such as transesterification, pyrolysis and emulsification [2]. However, these processes demand a lot of work and are time consuming. Hence blending vegetable oils with No.2 diesel can be done to minimize the viscosity of the vegetable oils and make them suitable for the CI engines. CI engine fuel blends of vegetable oils with diesel show similar combustion char- acteristics and reduced emissions when compared with diesel with minor power loss [3–5]. Every nation, worldwide has the potential to produce different kinds of edible and non-edible vegetable oil, based on their climate and geographic conditions and over S. Saravanan (&) Department of Automobile Engineering, Sri Venkateswara College of Engineering, Sriperumbudur, Chennai 602105, India e-mail: saran@svce.ac.in G. Nagarajan Department of Mechanical Engineering, College of Engineering, Anna University, Chennai, India G. Lakshmi Narayana Rao Department of Mechanical Engineering, Sri Venkateswara College of Engineering, Chennai, India 123 J Am Oil Chem Soc (2008) 85:663–666 DOI 10.1007/s11746-008-1246-6