Comparison of tar thermal cracking and catalytic reforming by char in a micro fluidized bed reaction analyzer

Abstract

In this study, a micro fluidized bed reactor analyzer (MFBRA) was adopted to test the isothermal reaction characteristics of tar catalytic reforming by char and thermal cracking by quartz sand from 1023 to 1223 K. The behaviors of tar conversion, the evolution of gaseous products generation, and the corresponding reaction kinetics were comprehensively analyzed. Compared to thermal cracking, the yield of catalytic cracking is higher. It can not only promote the tar conversion but also upgrade the fuel gas quality even at a low temperature of 1023 K, especially for CO, CH4, CO2, and C3H6. The tested activation energies (Ea) of tar conversion and gas generation (CH4, C2H6, C3H6, H2, CO2, and CO) in catalytic reforming were about 60.27, 45.48, 56.22, 71.34, 62.35, 51.51, and 60.75 kJ/mol, respectively, corresponding that of 78.16, 63.19, 71.16, 83.19, 84.33, 90.81 and 130.72 kJ/mol in thermal cracking. The lower Ea indicated the good catalytic activity of char on tar conversion and the change of gas generation paths by choosing char as a catalyst. Finally, the kinetics was compared with the results in the literature to verify the feasibility of MFBRA and the accuracy of testing results. This research deepened the understanding of tar catalytic reforming by char and was beneficial for developing a biomass gasification process with low tar generation.