Hydrogen Production from Waste Tyres: An Experimental and Simulation Approach to Perform the Techno-Economic Analysis

Due to continuous increase in population and rapid industrialization, global energy demand has been increasing over the last few decades. The massive use of fossil fuels to meet the energy demand has not only increased the global CO2 emissions up to ~415ppm but has also caused wreaked havoc in the form of global warming. The recent reports published by international environmental monitoring agencies including International Energy Agency (IEA), Danish Energy Agency (DEA) and Global Energy Outlook (GEO) also demands for the reduction in greenhouse gas emissions (GHG) to keep the global temperature rise below by 2 by 2050 followed by implementing stringent environmental policies. The forecasts done by these agencies have favored for the use of advanced process systems to generate clean energy based on energy-mix and fuel-switch technologies. Hydrogen is considered as a clean fuel with excellent combustion properties and has lower global warming potential. The demand for H2 has been increasing during the last two decades due to its extensive utilization in chemical, process and petrochemical industries. Most of the conventional hydrogen production processes utilizes methane-reforming technologies to get the higher HCR (hydrogen to carbon ratio) in the synthesis gas. However, the depletion in the natural gas resources followed by fluctuating fuel prices is pushing the research towards the development of non-conventional technologies with more fuel flexibilities. On the other hand, gasification technologies can be used for synthesis gas production from a wide variety of feedstocks ranging from solid to liquid fuels, even the municipal and organic wastes shows potential. However, the syngas from the gasification process usually yields low heating value synthesis gas with lower HCR. Recently, Waste-tyre gasification technologies have emerged to be an efficient pathway for the solid waste management that not only reduces the carbon footprint but also generates the value-added chemicals including H2. In this project, an integrated experimental and simulation based approach will be used to analyze the conversion of waste tyres into valuable fuels including tyre pyrolysis oil (TPO) and hydrogen. Waste tyres will be first pyrolyzed in an inert atmosphere to produce TPO, which will be further analyzed in a TGA-FTIR system to identify the process conditions (heating rate, temperature, residence time) for which the production of syngas with the higher HCR can be maximized. The obtained data from the experimental undertakings will be used for developing simulation models in Aspen Plus using waste-tyre as a primary feedstock for H2 production. Case 1 will be considered as the base case design where waste-tyres will be gasified to produce syngas followed by its validation based on experimental/literature results. The syngas will be then processed in the water-gas-shift reactors followed by the removal of acid gases (H2S and CO2) to increase the H2 purity. The case 2 process model will represent the framework of integrating waste-tyre gasification and state-of-art natural gas reforming technologies in the single model for maximizing the H2 production followed by its techno-economic assessment. The sequential integration of waste-tyre gasification and natural gas reforming technologies in the parallel design configuration using energy-mix and fuel switch process configurations will help in amplifying the production of H2. Some of the key technical (process efficiency, specific H2 production energy and CO2 emissions) and economic (Investment/H2 production, H2 selling price and Project feasibility) indicators will be used to evaluate both the models. Finally, the results from the experiments and developed models will be compared with the conventional processes to analyze the strengths and weaknesses of using waste-tyre as a feedstock in the proposed models.