Microwave-assisted pyrolysis of microalgae in producing bio-oil using CaO catalyst and charcoal as heat absorber

In the microwave-assisted pyrolysis process the solid material to be cracked requires an absorber material to capture microwaves to be converted into heat as a heat source and a catalyst to accelerate the pyrolysis process. This research is focused on studying the use of a potential heat absorber, namely coconut shell charcoal and CaO as catalyst in the microwave-assisted pyrolysis process in converting microalgae (dry Chlorella sp) into bio-oil. The round boiling flask as a reactor is placed in a microwave oven, equipped with a condenser and a vacuum pump. The operating variables were microwave power, pyrolysis time and catalyst ratio to microalgae. The products obtained consisted of 3 phases, namely solid residue (char), liquid product (bio-oil) and gas products. The results show that microwave power, pyrolysis time, and ratio of catalyst to microalgae using shell charcoal absorbent can provide an increase in product yield. The optimum yield is 20.57% of bio-oil obtained when the microwave power is 600 watts, 20 minutes, and CaO catalyst of 1 gr and ratio absorber to microalgae 1/6. The use of a mixture of catalyst and absorber improve the performance of pyrolysis in producing bio-oil from microalgae using microwave-assisted pyrolysis technology.