In view of energy conversion efficiency, the gas production from high water content (> 60 wt.%) biomass via gasification is necessarily conducted with fuel drying in advance. In regard to this kind of processes, the present study was devised to impregnate Ca onto fuel during fuel drying and thereby to increase fuel's gasification reactivity to raise the gas production efficiency with minimal additional cost. By employing wet coffee grounds as a model biomass fuel and slurry dewatering in kerosene as the adopted drying technology, the Ca impregnation was implemented through dosing Ca(OH)(2) into a fuel-kerosene slurry and in turn treating the slurry in the same way as for the case without Ca addition. The resulting Ca (4.0 wt.% load in CaO base) exhibited high dispersion through the fuel matrix in both SEM-EDX image and XRD spectrum. Gasification of the fuel in a pilot dual fluidized gasification setup further demonstrated that the fuel possessed distinctively high reaction reactivity. This led it to show C and H conversions of 91% and 138%, respectively, at a reaction temperature of about 1083 K, whereas these conversions were only 70% and 92% for the fuel with a similar amount of physically mixed CaO. The catalytic effect of the impregnated Ca manifested also on hydrocarbon reforming and water gas shift, making the resulting product gas evidently rich in H-2 and lean in CO and hydrocarbons. (c) 2006 American Institute of Chemical Engineers.