Evaluation of sorbents for high temperature removal of tars, hydrogen sulphide, hydrogen chloride and ammonia from biomass-derived syngas by using Aspen Plus

Abstract

Biomass gasification is a promising technology to produce secondary fuels or heat and power, offering considerable advantages over fossil fuels. An important aspect in the usage of producer gas is the removal of harmful contaminants from the raw syngas. Thus, the object of this study is the development of a simulation model for a gasifier including gas clean-up, for which a fluidized-bed gasifier for biomass-derived syngas production was considered, based on a quasi-equilibrium approach through Gibbs free energy minimisation, and including an innovative hot gas cleaning, constituted by a combination of catalyst sorbents inside the gasification reactor, catalysts in the freeboard and subsequent sorbent reactors, by using Aspen Plus software. The gas cleaning chain simulates the raw syngas clean-up for several organic and inorganic contaminants, i.e. toluene, benzene, naphthalene, hydrogen sulphide, hydrogen chloride and ammonia. The tar and inorganic contaminants final values achieved are under 1 g/Nm3 and 1 ppm respectively.