Co-pyrolysis of biomass and waste plastics for production of chemicals and liquid fuel: A review on the role of plastics and catalyst types
Aizatul Hikmah Zulkafli, Hamizura Hassan, Mohd Azmier Ahmad, Azam Taufik Mohd Din, Siti Maryam Wasli
Abstract
The increasing global fuel consumption and growing environmental concerns are the impetuses to explore alternative energy that is clean and renewable for fuel production. Converting biomass and plastic waste into high-value fuel and chemicals via co-pyrolysis technique may provide a sustainable remediation to this problem. This review critically discussed the influence of various types of plastic wastes as co-reactant in co-pyrolysis with biomass on the product distribution, synergistic effect, and quality of bio-oil. The outcome of this review revealed that the addition of plastic enhanced the yield and quality of bio-oil and inhibited the production of oxygenated compound and coke formation. Next, the critical role of zeolite-based catalyst (microporous, mesoporous, hierarchical, and metal modified zeolite) and low-cost mineral-based catalyst in upgrading the yield and quality of liquid fuel were compared and discussed. The characteristic, synthesis method, strength, and limitation of each catalyst in upgrading the products were summarized. Hierarchical zeolites can resolve the problems of mass transfer, and diffusion limitation of large molecules into active sites associated with conventional zeolite due to the combination of two levels of porosity. Finally, the potential challenges and future directions for this technique were also suggested.