University of Hohenheim, Institute of Agricultural Engineering, Tropics and Subtropics Group, Germany
The seed shells of Jatropha curcas are a promising fuel for combustion technology. Thermal energy can be used for various purposes, e.g. for drying of Jatropha fruits or for transesterification of Jatropha oil to produce biodiesel. Gross energy of Jatropha shells is about 18-19MJkg-1 and therefore comparable to rice husk and wood, which are still known as major energy source for dryers in rural areas of tropical and subtropical countries.
Shells from the de-shelling process are a bulky material which is comparable to rice husk. They consist of 50.9% carbon, 39.5% oxygen, 5.8% hydrogen and 0.8% nitrogen. Volatile matter and fixed carbon with values of 61% and 29% are comparable to rice husk. In general, combustion technologies for such fuels are readily available. However, for small scale combustion units, the technology and its operation have to be adapted accurately in order to reach a complete and clean combustion. In addition, the operation of the furnaces influences strongly efficiency and emission of toxic exhaust gas components. Furthermore, chemical composition of Jatropha shell and fusibility of fuel ash are influencing combustion behaviour. However, the fuel characteristics for Jatropha curcas seed shells are not yet available.
Therefore, the objective of this study is to investigate physical and chemical properties of Jatropha seed shells and to develop a combustion technology to be used by small scale farmers. Analysis of the combustion parameters of Jatropha seed shells and the analysis of combustion technologies is needed as a requisite for a systematic design process.
Keywords: Combustion, energy, Jatropha curcas, sedd shell