Catalytic Cracking Of Biomass Tar In Molten Salt

Removing and utilizing the tar from biomass gasification is one of the important questions in the process of biomass conversation. The catalytic cracking is one of the effective ways of removing tar. So the selection of catalyst is an important factor for catalytic cracking.In this thesis, the ZnCl2-KCl and LiCl-KCl were used to catalyze the cracking of the biomass tar. The main research contents are as follows:(1) Thermal gravimetric analysis of biomass tar was investigated The effect of heating rate, molten salt, adding different proportions of the molten salt on the pyrolysis of biomass tar were studied. The average activation energy was calculated with the FWO method and mechanism function was inferred with the Satava method, which is used to find the best concept of mechanism function in the different heating rate conditions.(2) The impact factors, such as pyrolysis temperature, feed rate, the rate of carrier gas and adding Raney-Ni, dolomite catalyst, were investigated with the mixture salt of ZnCl2-KCl and LiCl-KCl, respectively. The results showed that the higher the temperature was, the lower the yield of coke was; The water content in liquid was the lowest as adding Raney-Ni catalyst.(3) The raw material of biomass tar included38kinds of substances, such as,2-methoxy-4-methyl-phenol, phenol,4-ethyl-2-methoxy-phenol,2-methoxy-phenol and so on, which were detected by the gas chromatography mass spectrometry (GC-MS). The liquid component and different pyrolysis temperatures were also investigated. The results showed that the numbers of tar components reduced with the increasing temperature.(4) The components of the pyrolysis gas were analyzed using gas chromatography (GC). The results showed that LiCl-KCl was favorable to the formation of H2, CH4and inhibitive to the formation of CO2. Increasing temperature could increase the yield of H2and CH4, decrease the yield of CO2. The change of temperature had little effect on the yield of CO.