Techno-Economical Analysis for a 3 MWth Gasification Plant Revamping: Use of Enriched Air and Steam as Gasifying Agent

Abstract

An assessment of the revamping of a 3 MWth atmospheric­pressure bubbling fluidized bed biomass gasifier was made in order to study the techno­economical viability of changing the gasifying agent from air to a mixture of enriched air based on membrane technology (up to 40% in volume oxygen) and low­pressure saturated steam. The expected changes in the gasification yields were obtained from extrapolating the yields of the non­condensable main gases (H2, CO, CO2 and CH4) measured in a 100 kWth pilot plant facility. The main variables for the economical sensitivity analysis included the initial investment for the new equipment, the operating hours per year and the plant capacity (biomass flowrate). Net present values of up to 180 k€ and internal rate of return of up to 20% could be achieved. The results show that this gasification concept seems to be an interesting and viable option for standalone direct air­blown fluidized bed gasifiers.