Production of a Clean Hydrogen-Rich Gas by the Staged Gasification of Biomass and Plastic Waste

Gasification is a promising route for producing hydrogen by converting feedstock into a product gas called syngas or producer gas. In particular, the gasification of biomass and plastic waste has been widely studied worldwide to confront the energy crisis and environmental pollution. However, one main obstacle needs to be overcome for the industrial implementation of biomass and plastic gasification: problems associated with contaminants generated during gasification. Among contaminants, tar is regarded as the most difficult to treat. Condensed tar can cause operational issues by blocking joint pipelines or fouling process equipment. Moreover, tar in syngas can limit its downstream applications. For example, hydrogen in syngas can be used for the synthesis of chemicals and fuels only when the syngas contains an extremely low level of tar. This chapter describes the challenges of and solutions for the gasification of biomass and plastic waste to produce a hydrogen-rich gas. In this regard, detailed experimental results are described for the gasification of wood, dried sewage sludge, and plastic waste. In particular, the characteristics and performance of newly developed staged gasifiers for the production of a hydrogen-rich gas with low concentrations of impurities are reported and evaluated.