The catalytic activity of a new catalytic filter of combined design consisting of a catalytic filter candle with an integrated catalytic ceramic foam was calculated under model gas conditions at 800 and 850 degrees C in the absence and presence of 100 ppmv H2S on the basis of separate and combined measurements of appropriate catalytic filter element and ceramic foam disk samples. Real gas validation of the determined model gas activity of the catalytic filter of combined design in a bench-scale gasifier was performed to check-up, if model gas conversions can be used as bases for the prediction of real tar conversions. A calculation of the model gas activity of the catalytic filter at a superficial velocity of 2 cm/s based on the disk measurements results to 99% naphthalene conversion at 850 degrees C in the absence of H2S and 94% in the presence of 100 ppmv H2S. At 800 degrees C, the calculated conversion is 95% in the absence and 70% in the presence of 100 ppmv H2S resulting in an estimated conversion of 85% at an H2S content of 40 ppmv. This value is comparable with the measured real tar conversion of 81% at 790 degrees C and a superficial velocity of 2.5 cm/s. (C) 2015 Elsevier B.V. All rights reserved.