Progress in deep cleaning and upgrading of biomass- and waste-derived syngas for production of renewable fuels, chemicals and power

The cleaning of syngas for the production of renewable fuels, chemicals and power is reviewed here. Recent progress in syngas cleaning pathways and key utilization routes, along with techno-economics are discussed, with the goal of investigating the requirements of crude syngas towards clean syngas and finally towards fuels and chemicals as a sustainable and eco-friendly technology. The impacts of feedstock composition, type and characteristic properties on syngas quality coupled with the role of different impurities are examined. Furthermore, adaptation of process parameters and its impact on the syngas quality is discussed. Cleaning of crude syngas is considered a critical issue to generate renewable fuels and chemicals, and therefore, diverse pathways (conventional such as hot and cold cleaning methods, catalytic cleaning and thermal cracking and, advanced techniques such as membranes, pressure swing adsorption, and cryogenic separation) are presented to allow effective cleaning which in turn can enable syngas deployment in various applications. Bio-methane has emerged as a beneficial alternative for conventional transportation fuel with all the advantages of natural gas including a dense distribution, trade and supply network. Gasification is a proven technology while gas cleaning is still one limiting factor since “classical” pathways are labor and cost intensive, especially when it comes to residues and waste materials as feedstock. Gasification of organic feedstock materials (clean biomass, residues and waste) followed by chemical synthesis is a key-technology to substitute chemicals and fuels from fossil sources. These syngas-derived fuels and chemicals have the potential to provide sustainable energy and curb climate change to a major extent and therefore, can be a step forward towards the United Nation's Sustainable Development Goals 7 and 13.