A rational and feasible approach to the co-management of condensates from biomass torrefaction and carbon-rich fly ash from fluidized-bed coal gasification

•A promising approach to co-management of FA and TC was explored.•A new acidic index was proposed to evaluate the effective acidity of TCs.•TC dissolved and dispersed locally aggregated Ca minerals as in-situ catalysts.•Highly-dispersed Ca improved many-fold reactivity and syngas yield of the FATCs.•TCs played an apparent desulfurization role during the blending of FA and TCs.