Plastic Waste Upcycling for Generation of Power and Methanol: Process Simulation and Energy-Exergy-Economic (3E) Analysis

To address the global issue of plastic waste, the waste to wealth technique is under investigation. Four processes, known as INP-CC (incineration with carbon capture and power generation), GFP-CC (gasification with carbon capture and power generation), INP-ME (incineration with methanol and power cogeneration), and GFP-ME (gasification with methanol and power cogeneration), which include both traditional and innovative methods, have undergone development, simulation, and comprehensive comparison through techno-economic analysis. GFP-CC and GFP-ME are particularly favored for their energy efficiencies of 43.47 and 34.91%, respectively, in comparison to INP-CC (17.6%) and INP-ME (6.89%). Exergy flow diagrams reveal that the incinerator, gasifier, and combustion chamber account for over 50% of the exergy loss, highlighting their potential for intensification. However, from an economic standpoint, without a larger subsidy fee ($84 per ton) or higher methanol selling price ($550 per ton), processes GFP-ME and INP-ME are not economically attractive due to a negative net present value over 20 years. A sensitivity analysis of key economic parameters demonstrates that the price of methanol and hydrogen has the greatest impact on process economic performance. It appears that process INP-ME is more resilient in terms of economic performance when subjected to the same level of fluctuations in methanol and hydrogen prices, in comparison to GFP-ME.