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Currently, various methods have been developed to overcome the problems caused by garbage. Pyrolysis is one methode of waste processing which is considered to be prospective enough to be developed. It's because some advantages such as high conversion ratio and high energy content and potency as an alternative fuel in the future. Therefore, in this paper characteristics of pyrolysis will be studied. The waste materials used are catalyst and plastic waste. The resultant products of the pyrolysis process analyzed by Gas Chromatography / Mass Spectroscopy (GC / MS), while the thermal decomposition analysis was performed using Thermo Gravimetric Analysis (TGA). The results of pyrolysis process in isothermal conditions of a single component and a mixture of plastic waste and natural catalyst show that the final temperature of pyrolysis and the rate of heating affects to the distribution of pyrolysis products for all samples. As pyrolytic temperatures increase, liquid and gas products increase, while solid products tend to decrease. In the temperature range of 300°C, 400°C, 500°C, 600 o C pyrolysis temperature with a heating rate of 100°C / min is the ideal temperature for obtaining the pyrolysis product of the liquid fraction and and the maximum gas fraction for all waste types studied.

Efforts to improve the physical and chemical properties of vegetable oils as diesel fuels such as viscosity and calorific value are indispensable with the depletion of fossil oil reserves. Jatropha oil with long chain fatty acids and high degree of unsaturation is mixed with short chain saturated fatty acid coconut oil in various compositions. The mixture was heated and stirred for 30 min at 90 • C. This mixing leads to a decrease in viscosity which allows for the breaking of the bond. The fatty acid molecule structure undergoes transformation that changes the degree of unsaturation and the average length of the carbon chain. Consequently, the kinematic viscosity and flash point of the mixture decreases while its calorific value increases.

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Paraffin melting experienced in the nozzle-and-shell, tube-and-shell, and reducer-and-shell models in thermal storage with 3D numerical and experimental approach has been studied. The numerical study aims to evaluate the melting process and discover temperature distribution, liquid-solid interface, liquid fraction, and the average surface Nusselt number, while the aim of this experimental study is to determine the distribution of melting temperature. The comparison of temperature distribution between the numerical approach and experimental one indicates a good agreement. The comparison result between the three models shows that the melting process of the nozzle-and-shell model is the best, followed by tube-and-shell and reducer-and-shell models, successively. To finish the melting process, the time required is 6130 s for the nozzle-and-shell model, while tube-and-shell model requires 8210 s and reducer-and-shell model requires 12280 s.