Study of Thermal Heating of Waste Engine Oil in a Microwave Pyrolysis Reactor

The purpose of this study is to investigate the effect of microwave power and irradiation time, as well as the effect of types of absorber on thermal characteristics of microwave reactor during pyrolysis of waste engine oil. This study is needed to provide basic knowledge into the fundamentals of microwave heating process for pyrolysis of waste engine oil. In this work, a domestic microwave oven with a maximum output power of 418 W was modified and used as the experimental reactor. Two types of absorber, i.e., wood char and coconut shell char were also employed to enhance reaction temperature. The char loading was tested in the level of 75 g. The samples were examined under various microwave power of 257 W, 362 W and 418 W for 60 min of irradiation. Microwave power and irradiation time significantly affect thermal characteristics of microwave reactor. The higher the microwave power, the higher the reactor temperature, heating rate and thermal efficiency. Coconut shell char provided better results compared to wood char as absorbers. Reactor temperature, heating rate and thermal efficiency of 639 degrees C, 10.05 degrees C min(-1) and 25.53%, respectively could be obtained with the use of 75 g coconut shell char at 418 W microwave power. It can be concluded that waste engine oil can only be processed in microwave pyrolysis reactor with the aid of an absorber material.