Techno-economic study of bio-SNG and biochar production by a city-refinery gasification plant in Crete

Biomass is one of the renewable energy sources (RES) with the greatest potential to contribute to global energy needs. Therefore, biomass gasification is a key technology to fulfill the goal of sustainable RES systems, as syngas, as the main process product can be used as fuel in various conversion technologies, to produce different products, including biofuels. Consequently, techno-economic studies are imperative to define the viability of these technologies and to optimize energy consumption and costs. The work presented is a techno-economic feasibility study of bio-based synthetic NG and high value biochar production to contribute to power needs and public transport requirements in a small community. In particular, a 20 MW thermal input city-refinery gasification plant in Crete island (Greece) will operate primarily on RDF and secondly on agricultural residues (such as olive pruning). A fluidized bed gasifier was considered to produce the required biofuel. After process configuration modeling in Aspen Plus and the heat and mass balance calculations, a cost analysis was performed where capital cost, operational and maintenance (O&M) costs for the gasification plant, the syngas cleaning process, and the bio-SNG synthesis unit were considered in the assessment. Bio-SNG product selling value and payback project period indicate the sustainability character of the achievement.