Catalytic elimination of tars contained in the produced gas is crucial to improve the process of biomass gasification in circulating fluidized bed gasifier-permitting gas cleanup and increasing syngas (CO+H-2) yield. Natural olivine, often used as primary catalyst, was previously improved by Ni addition. The catalyst Ni/olivine developed and tested in pilot scale showed very good performances in tar reduction and increasing H-2 content in the produced gas. To understand the tar decrease, a model study in laboratory scale fixed bed reactor of toluene steam reforming is presented here. The toluene conversion obtained with Ni/olivine at 560 degrees C is the same as with olivine at 850 degrees C. Moreover, with Ni/olivine only CO, CO2 and H-2 are produced but with olivine similar to 20% of benzene, polyaromatics and methane are formed additionally to the previous gases. Carbon deposit characterised by TEM and TPO is negligible at 800 degrees C due to the specific Ni-olivine interactions. A kinetic model established, taking into consideration a zero order for water and first order for toluene gives the kinetic parameters (E-a = 196 kJ mol(-1) and A(k ') = 3.14 x 10(-3) m(3) (kg(cat) h)(-1)) comparable to those reported for steam reforming of benzene or tars on commercial nickel catalysts. (C) 2007 Elsevier B.V. All rights reserved.