Tetrapak waste treatment using microwave pyrolysis to produce alternative gas fuels

Tetrapak waste is one of the most abundant wastes in the world. It consists of layers of paper, LDPE, and aluminium foil. It is difficult to recycle, however it can be converted into valuable gaseous fuel if processed by microwave heat using a dual reactor catalytic process, SiC as microwave absorber, and natural zeolite as catalyst. The sample was pyrolyzed at different Microwave Output Power (MOP) levels (300, 450, 600, and 800 W) and Catalytic Temperatures (CT) levels (350, 400, 450, and 500°C) for 30 minutes. The results showed that the MOP and CT levels positively affect the increase of the yield and improve the heating value of the gas product. For instance, at 800 W, the gas yield increased from 73 wt.% in the process without catalyst to 78 wt.% in the catalytic temperature of 500°C. The same effect occurred when various MOP levels were used. The gas yield increased when the MOP level raised. H2, CH4, CO, CO2, and other hydrocarbons with low molecular weights (C2+) are the major components of gas products. The presence of catalyst, an increase in CT, and a rise in MOP all boosted the generation of syngas (H2 + CO) up to 54.55 wt.%. The gas yields from this experiment have a LHV of 21.97–23.46 MJ/m3 and total energy of 34.59–171.24 kJ. The high-quality gaseous products can be used as alternative fuels or feed gas for chemical synthesis.