Techno-Economic Analysis of the Conversion of Waste Plastics to Hydrogen Fuel

Abstract

The need of hydrogen as a clean fuel has grabbed a lot of global attention. Therefore, various processes have been developed for hydrogen production. Conversion of plastic wastes is one of the attractive option to produce H 2 because of its hydrocarbon structure, higher heating value and availability. Polyethylene (PE) and polypropylene (PP) are considered in this study because of their massive worldwide availability in the category of waste plastics. In this study, the simulation of conversion of plastic wastes (PE and PP) to hydrogen fuel via steam gasification process is developed to perform the techno economic analysis. The composition of produced syngas from steam gasification unit was validated with the literature results followed by sensitivity studies to see the impact of various process parameters on the syngas composition. The syngas produced in the steam gasification unit is then treated in the water gas shift units followed by acid gas (H 2 S and CO 2 ) removal to produce pure H 2 . To enhance the hydrogen production capacity and overall process efficiency, plastic gasification is further integrated with the steam methane reforming coincided with gasification to utilize the energy from the gasifier to provide heat to the natural gas reformer. It has been seen from results that the new integrated design containing both gasifier and reformer enhances the hydrogen mass production rate per mass feed rate by 5.6%. Furthermore, the process performance analysis showed that the efficiency of the new process is increased up to 1.82%, where the hydrogen production cost showed the reduction of 29% compared to the standalone gasification cases. In terms of carbon dioxide specific emission, the new design showed the reduction in CO 2 emissions by 4.0%. Overall, the technical and economic analysis favored the new design over the standalone plastic gasification case.