Several research works published in the area of hot gas cleaning for biomass gasification use heterogeneous metal catalysts such as nickel and ruthenium, with support materials such as silica oxide and alumina oxide used to convert tar to gas [93-95].Combinations of stable metals as nickel and ruthenium and stable support materials such as zirconium and titanium have been developed for the low temperature steam reforming of tar [96].Although nickel and other stable metal catalysts can almost completely remove tar, they are expensive ,easily deactivated and poisoned at high temperature. Several groups [68’97-100] have investigated a system of raw gas cleaning that involves a combined of nickel-dolomite or alkali metal catalyst for steam reforming of tar using metallic nickel as