• Energy Research

Abstract Recently, biodiesel has been gaining market share against fossil-origin diesel due to its ecological benefits and because it can be directly substituted for traditional diesel oils. However, the high cost of the raw materials required to produce biodiesel make it more expensive than fossil diesel. Therefore, low-priced raw materials, such as waste cooking oil and animal fats, are of interest because they can be used to drive down the cost of biodiesel. We have produced biodiesel from camel fat using a transesterification reaction with methanol in the presence of NaOH. The experimental variables investigated in this study were the temperature (30–75 °C), reaction time (20–160 min), catalyst concentration (0.25–1.5%), and methanol/fat molar ratio (4:1–9:1). A maximum biodiesel yield of 98.6% was obtained. The fuel properties of biodiesel, such as iodine value, saponification value, density, kinematic viscosity, cetane number, flash point, sulfur content, carbon residue, water and sediment, high heating value, refractive index, cloud point, pour point, and distillation characteristics, were measured. The properties were compared with EN 14214 and ASTM 6751 biodiesel standards, and an acceptable level of agreement was obtained.

The optimum conditions to produce palm fatty acid distillate (PFAD)-derived-methyl esters via esterification have been demonstrated with the aid of the response surface methodology (RSM) with central composite rotatable design in the presence of heterogeneous acid catalyst. The effect of four reaction variables, reaction time (30–110 min), reaction temperature (30–70°C), catalyst concentration (1–3 wt.%) and methanol : PFAD molar ratio (3 : 1–11 : 1), were investigated. The reaction time had the most influence on the yield response, while the interaction between the reaction time and the catalyst concentration, with an F -value of 95.61, contributed the most to the esterification reaction. The model had an R 2 -value of 0.9855, suggesting a fit model, which gave a maximum yield of 95%. The fuel properties of produced PFAD methyl ester were appraised based on the acid value, iodine value, cloud and pour points, flash point, kinematic viscosity, density, ash and water contents and were compared with biodiesel EN 14214 and ASTM D-6751 standard limits. The PFAD methyl ester was further blended with petro-diesel from B0, B3, B5, B10, B20 and B100, on a volumetric basis. The blends were characterized by TGA, DTG and FTIR. With an acid value of 0.42 (mg KOH g −1 ), iodine value of 63 (g.I 2 /100 g), kinematic viscosity of 4.31 (mm 2 s −1 ), the PFAD methyl ester has shown good fuel potential, as all of its fuel properties were within the permissible international standards for biodiesel.

Sulfonated kenaf seed cake (SO3H-KSC) catalyst, was synthesized to aid biodiesel production from palm fatty acid distillate (PFAD). It was chemically activated with phosphoric acid for an impregnation period of 24 h in order to enhance the porosity and the specific surface area of kenaf seed cake (KSC). After the carbonization and sulfonation, the resultant catalyst was characterized with powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscope (FESEM), NH3-temperature programmed desorption (NH3-TPD) and thermogravimetric analysis (TGA). The SO3H-KSC catalyst was amorphous in nature and had an acid density of 14.32 mmol/g, specific surface area of 365.63 m2/g, pore volume of 0.31 cm3/g and pore diameter of 2.89 nm. At optimum esterification conditions--reaction time 90 mins, temperature of 338 K, methanol:PFAD molar ratio of 10:1 and catalyst concentration of 2 wt.%—a free fatty acid (FFA) conversion of 98.7% and fatty acid methyl esters (FAME) yield of 97.9% was achieved. The synthesized SO3H-KSC catalyst underwent five reaction cycles while maintaining a fatty acid methyl esters (FAME) yield and free fatty acid (FFA) conversion of >90%. Thus, the SO3H-KSC catalyst was shown to be an excellent application of bio-based material as a precursor for catalyst synthesis for esterification of PFAD.

Abstract Many industrial applications involve the transesterification of natural oils and fats. In the present work, methyl esters were transesterified from white mahlab oil (WMO) using methanol via base and lipase-catalyzed reactions. The oil content of the mahlab seeds was found to be 31%. The composition of the fatty acid methyl esters (FAMEs) produced from the WMO was analyzed by GC/MS, revealed α-eleostearic acid (40.7%), oleic acid (29.8%) and linoleic acid (26.6%). The effects of the reaction conditions ( i.e. , time, temperature, the amount of catalyst, methanol/oil molar ratio, water content and the amount of solvent) on FAME’s yield were appraised. The important fuel properties of the FAME’s were measured and compared with ASTM 6751 and EN 14214 biodiesel standards.

Abstract Yucca aloifolia Linn ( Y. aloifolia ) is a drought-resistant arid land plant that grows in most soil types. In this work, Y. aloifolia seed oil (YAO) was evaluated for the first time as a potential biodiesel feedstock, which contains 16.23% oil (w/w) whereas the acidity of the oil was 11%. Two step processes i.e. acid-catalyzed esterification to reduce the acid value of YAO and then standard base-catalyzed transesterification procedure were used to synthesis the Y. aloifolia methyl esters (Yame) at optimization conditions. YAO has a high content of linoleic acid (70.77 %) followed by oleic acid (12%), and palmitic acid (8.59%). The fuel properties of biodiesel derived from YAO including density, iodine value, kinematic viscosity, cetane number, flash point, pour point, cloud point, and gross heating value were evaluated and compared with the limits of ASTM D6751 standards. The comparison showed that the biodiesel obtained from Y. aloifolia oil could be used as an alternative fuel for diesel engines.

Rhazya stricta Decne (R. stricta) is a hardy, drought-resistant, and arid land plant that is widely distributed from the Middle East to South Asia. The aim of this study was to evaluate the use of R. stricta seed oil as an alternative source of triacylglycerols that may be suitable for the synthesis of biodiesel. The oil content of the seeds was approximately 14% and was mainly composed of the fatty acids linoleic (60.95%) and oleic (25.48%) acid. R. stricta methyl esters (RSME) were prepared by a base-catalyzed transesterification reaction. The conversion rate of the triacylglycerols to the corresponding methyl esters was determined by H-1-NMR to be approximately 97%. This study showed that the fuel properties of the RSMEs are comparable to other vegetable oil methyl esters that are commonly used as biodiesels. R. stricta plantations will therefore be suitable for promoting sustainable agriculture and for producing biodiesel with viable prices in arid and semi-arid regions throughout the world. (C) 2014 Elsevier Ltd. All rights reserved.