Technoeconomic Feasibility of Hydrogen Production from Waste Tires with the Control of CO₂ Emissions

The worldwide demand for energy is increasing significantly, and the landfill disposal of waste tires and their stockpiles contributes to huge environmental impacts. Thermochemical recycling of waste tires to produce energy and fuels is an attractive option for reducing waste with the added benefit of meeting energy needs. Hydrogen is a clean fuel that could be produced via the gasification of waste tires followed by syngas processing. In this study, two process models were developed to evaluate the hydrogen production potential from waste tires. Case 1 involves three main processes: the steam gasification of waste tires, water gas shift, and acid gas removal to produce hydrogen. On the other hand, case 2 represents the integration of the waste tire gasification system with the natural gas reforming unit, where the energy from the gasifier-derived syngas can provide sufficient heat to the steam methane reforming (SMR) unit. Both models were also analyzed in terms of syngas compositions, H₂ production rate, H₂ purity, overall process efficiency, CO₂ emissions, and H₂ production cost. The results revealed that case 2 produced syngas with a 55% higher heating value, 28% higher H₂ production, 7% higher H₂ purity, and 26% lower CO₂ emissions as compared to case 1. The results showed that case 2 offers 10.4% higher process efficiency and 28.5% lower H₂ production costs as compared to case 1. Additionally, the second case has 26% lower CO₂-specific emissions than the first, which significantly enhances the process performance in terms of environmental aspects. Overall, the case 2 design has been found to be more efficient and cost-effective compared to the base case design.