Techno-economic analysis of mixed plastic waste-to-chemical plants

The accumulation of plastic waste represents a significant environmental issue, requiring innovative strategies for its effective management and conversion. This thesis explores the gasification of mixed plastic waste into methanol by using two different configurations of chemical reactor: the FastOx gasifier and the fixed bed. Different process design configurations are considered for each reactor typology, to assess the best options with the aim of maximising the techno-economic performance of the overall system. In particular, the technical performance is assessed by analysing indicators such as efficiencies and performance metrics (e.g. the carbon conversion efficiency and the cold gas efficiency), while the economic evaluation is carried out to determine the capital cost, operational expenses, and revenues of the plastic-to-methanol plant. The findings indicate that while both reactors have distinct advantages, the choice of gasification technology largely depends on specific operational objectives and economic limitations. The FastOx reactor exhibits superior efficiency and requires a lower amount of oxygen, making it more suitable for applications requiring high-quality syngas. Differently, the fixed bed reactor provides a more cost-effective solution with simpler operational demands, although with slightly lower performance metrics.