Biodiesel Fuel from Jatropha

The use of Jatropha as a potential Biodiesel feedstock in Egypt is the focus of an ongoing US-Egypt joint investigation. "Biodiesel Fuel from Nonedible Vegetable Oils" is a collaborative project of the UNH Biodiesel group and the National Research Center (NRC), Cairo. Jatropha crop has low production costs, and high biomass yield (around 1550 kg oil per hectare). The capability of growing Jatropha in eroded soil and arid land and the need for hot climate makes Jatropha ideal for Egypt. In fact, Jatropha has been successfully grown in southern Egypt to green the desert, and utilize treated municipal wastewater for irrigation of Jatropha. An added benefit is to use the Jatropha seeds as a feedstock to produce Biodiesel, an environmentally friendly renewable diesel fuel alternative. This requires a two-step approach; the extraction of the Jatropha oils from the seed, and the conversion of the extracted oil to Biodiesel, according to the following transesterification reaction.

Oil + 3 Methanol [using NaOH or KOH catalyst] = 3 Biodiesel (Methyl Ester) + Glycerol.

The objectives of the research were to study the oil extraction, and the transesterification of the extracted oil to Biodiesel. For the oil extraction the specific objectives were to determine the relationship between the Jatropha oil yield and amount of solvent, type of solvent and method of extraction (mechanical vs. solvent). In the case of solvent extraction a soxhlet was used as an apparatus. Five solvents were selected; hexane, isopropanol, methanol, 3:2 and 2:3 hexane: isopropanol mixture). The mechanical extraction was done using a hydraulic press. After dehulling, the Jatropha seeds were first pressed to extract oil and then placed inside a soxhlet and brought into contact with a condensed solvent. The solvent dissolves the oil and then it is later separated using a rotor vapor. The obtained Jatropha oil was used for Biodiesel production. The transesterification reaction was done using methanol and two basic catalysts. The yield of Biodiesel was compared when potassium Hydroxide (KOH) and Sodium Hydroxide (NaOH) were used as catalyst. In addition the cost of raw materials per ton of Biodiesel produced using NaOH and KOH was also determined. This paper will discuss the work done, the experimental setup, and the results obtained. The conclusions reached include: as the mass ratio of solvent: seed increases the Jatropha oil yield also increases; 3:2 Hexane: Isopropanol mixture had the highest oil yield compared to Isopropanol, Hexane, and 2:3 Hexane: Isopropanol mixture; Hexane has a higher oil yield than Isopropanol; Methanol is a poor solvent for the oil extraction (that is why KOH or NaOH catalyst is needed in the transesterification reaction); Solvent extraction has higher oil yield than hydraulic press extraction; Jatropha oil extracted using Isopropanol as solvent is darker than when hexane is used. The transesterification of Jatropha oil to Biodiesel showed that the using KOH as a catalyst gives higher yield of Biodiesel and produces a darker color glycerol than using NaOH as a catalyst. In addition, preliminary costing calculations showed that the cost of raw materials per kilogram of Biodiesel produced increases by 13% when NaOH was used compared to KOH; and that the costs of Jatropha oil and alcohol are roughly 90% of the total cost of the raw materials needed to produce Biodiesel.

Acknowledgements

The "Biodiesel Fuel from Nonedible Vegetable Oils" project is funded by the US-EGYPT Science and Technology Program, project No.: ENG-8-001-001 which the authors would like to acknowledge. The authors would like to acknowledge and thank the UNH Undergraduate Research Opportunities Program (UROP), Summer Undergraduate Research Fellowships (SURF) Abroad program and Dr. Donna B. Brown, UROP director for funding the first author to travel to Egypt and carry out the research. The first author would like to extend specials thanks to his mentors Dr. Ihab Farag and Dr. Guzine El Diwani for their support and guidance. This project was done at the Chemical Engineering and Pilot Plant Unit, National Research Center (NRC), Cairo, Egypt. The authors also like to thank the Faculty of the National Research Center (NRC) in Cairo, Egypt.