Techno-Economic Evaluation of Thermal and Catalytic Pyrolysis Plants for the Conversion of Heterogeneous Waste Plastics to Liquid Fuels in Nigeria

Abstract

Techno-economic potentials of thermal and catalytic pyrolysis plants for the conversion of waste plastics to liquid fuels have been widely studied, but it is not obvious which of the two plants is more profitable, as the existing studies used different assumptions and cost bases in their analyses, thereby making it difficult to compare the economic potentials of the two plants. In this study, industrial-scale thermal and catalytic waste plastics pyrolysis plants were designed and economically analyzed using ASPEN PLUS. Amorphous silica-alumina was considered the optimum catalyst, with 3:1 feed to catalyst ratio. Based on 20,000 tons/year of feed and 20% interest rate, the catalytic plant, having a net present value (NPV) of � million, was found to be economically less attractive than the thermal plant, having the NPV of �.4 million. On the contrary, sensitivity analyses of the two plants at a feed rate of 50,000 tons/year gave rise to a slightly higher NPV for the catalytic plant (� million) than the thermal plant having NPV of � million, thereby making the former more economically attractive for processing large amounts of waste plastics into liquid fuels. Consequently, as the catalytic plant showed a better scale economy and would produce higher quality liquid fuels than the thermal plant, it is recommended for commercialization in Nigeria.