Microwave-assisted catalytic fast co-pyrolysis of soapstock and waste tire for bio-oil production

•It is the first time that soapstock and waste tire were used for microwave-assisted catalytic fast co-pyrolysis.•An improved fast microwave-assisted catalytic pyrolysis system was developed.•Waste tire can promote the production of aromatics in the co-pyrolysis process.•The effects of several parameters on product fractional yields and chemical composition.•It is the first time that soapstock and waste tire were used for microwave-assisted catalytic fast co-pyrolysis.•An improved fast microwave-assisted catalytic pyrolysis system was developed.•Waste tire can promote the production of aromatics in the co-pyrolysis process.•The effects of several parameters on product fractional yields and chemical composition.

Microwave-assisted catalytic fast co-pyrolysis using HZSM-5 as catalyst was tested on soapstock and waste tire. Effects of co-pyrolysis temperature, catalyst to feed ratio and soapstock to tire ratio on product fractional yields and chemical composition were studied. Experimental results indicated that the optimal co-pyrolysis temperature was 550 °C, where the highest yield of bio-oil and proportion of aromatics in the bio-oil was obtained. The use of catalyst enhanced the proportion of aromatics, but reduced the yield of bio-oil. Waste tire presented a significant synergistic effect with soapstock to facilitate the production of aromatics in the bio-oil. In addition, the char as a by-product can be used as soil amendment or solid fuel.