Int. Journal of Renewable Energy Development 4 (2) 2015: 131-136 Page | 131 © IJRED – ISSN: 2252-4940, July 15, 2015, All rights reserved Contents list available at IJRED website Int. Journal of Renewable Energy Development (IJRED) Journal homepage: http://ejournal.undip.ac.id/index.php/ijred Comparative Analysis of Biodiesels from Calabash and Rubber Seeds Oils J.O. Awulu a , G.O. Ogbeh b and N.D. Asawa c a, b & c Department of Agricultural and Environmental Engineering, University of Agriculture, P.M.B. 2373 Makurdi, Nigeria Abstract: Physicochemical properties of biodiesel from vegetable oils depend on the inherent properties of the oil-producing seeds. The purpose of this study is to investigate the physicochemical properties of biodiesels extracted from calabash and rubber seeds oils, as well as their combined oil mixtures with a view to ascertaining the most suitable for biodiesel production. Calabash and rubber seeds oils were separately extracted through the use of a mechanical press with periodic addition of water. Biodiesels were produced from each category of the oils by transesterification of the free fatty acid (FFA) with alcohol under the influence of a catalyst in batch process. The physicochemical properties of the biodiesels were investigated and comparatively analysed. The results obtained indicated an average of 1.40 wt% FFA for biodiesel produced from the purified calabash oil, which has a specific gravity of 0.920, pH of 5.93, flash point of 116 0 C, fire point of 138 0 C, cloud point of 70 0 C, pour point of -4 0 C, moisture content of 0.82 wt% and specific heat capacity of 5301 J/kg K. Conversely, the results obtained for biodiesel produced from the purified rubber oil showed an average of 33.66 wt% FFA, specific gravity of 0.885, pH of 5.51, flash point of 145 0 C, fire point of 170 0 C, cloud point of 10 0 C, pour point of 4 0 C, moisture content of 1.30 wt% and specific heat capacity of 9317 J/kgK. However, results obtained for biodiesel produced from the combined oil mixtures indicated an average of 19.77 wt% FFA content, specific gravity of 0.904, API gravity of 25.036, pH value of 5.73, flash point of 157 0 C, Fire point of 180 0 C, cloud point of 9 0 C, pour point of 5 0 C, moisture content of 0.93 wt% and specific heat capacity of 6051 J/kg.K. Biodiesel produced from calabash seed oil is superior in quality to rubber seed oil, particularly in terms of its low FFA and moisture contents. Keywords: Oils, Calabash, Rubber, Transesterification, Biodiesel. Article History: Received April 16, 2015; Received in revised form May 19, 2015; Accepted June 20, 2015; Available online How to Cite This Article: Awulu, J.O., Ogbeh, G.O. and Asawa, N.D., (2015) Comparative analysis of biodiesel from calabash and rubber seed oil. Int. Journal of Renewable Energy Development, 4(2), 131-136. http://dx.doi.org/10.14710/ijred.4.2.131-136 1. Introduction Fossil fuels, particularly petroleum, natural gas and coal have been the dominant sources of global energy supply for decades. But because these energy sources are non-renewables and the reserves are rapidly being depleted; couples with the incessant environmental problems such as air pollution and global warming that are associated with them, efforts are increasingly being made to harness sustainable energy from renewable resources. Renewable energy sources provide 25% of the total global energy, of which 14-16% is provided from biomass (Itodo 2007). Interestingly, alternative fuels, such as biodiesel, biohydrogen, biomethane and bioethanol are increasingly being generated from biomass in several places around the world. Biodiesel has taken the centre stage in several biomass and biofuel-based studies because it is produced from vegetable oils, which have the advantage of renewability (carbon neutral), biodegradability, safety, portability, non-toxicity, high heat content (about 88% of diesel fuel), better lubricity, lower sulphur and aromatic contents. It is strongly recommended to be used in place of petroleum-based diesel in diesel engines. Unlike the other biofuels which require some form of modifications before they can be effectively utilized in their respective areas, biodiesel can be used in diesel engines with little or no modifications. Moreover, vegetable oils, the precursor of biodiesel are biodegradable because they have both lipid soluble and water soluble properties (Koh et al. 2011). Edible vegetable oils such as sunflower, soyabean, rapeseed, corn, and canola have been used for biodiesel production. Non-edible vegetable oils like Jathropha curcas and others have also been found suitable. So far, more than 95% of the global biodiesel *corresponding author: email: ogbeh.gabriel@yahoo.com