Study On Pyrolysis Characteristics Of Shenfu Coal (catalysis)

The coal resources are relatively rich than oil and natural gas in China. The sub-bituminous coal with low sulfur, low phosphorous, low ash and high volatile content occupies over forty percent of coal resources. It has aroused great interests of how to improve the utilize efficiency and reduce the conversion cost according to the structure characteristics of sub-bituminous coal. Using ShenFu coal, a typical sub-bituminous coal in the north of Shaanxi Province, as material. The TG-FTIR was used to reasearch the fundamental pyrolysis characteristic of ShenFu coal and the Powder-Particle Fluidized Bed(PPFB) was used to study the characteristic of fluidization, rapid pyrolysis and product distribution.The TG-FTIR was used to research on the effects of pyrolysis temperature, atmospheres and adding molecular sieve catalyst on the weight loss of SF coal(SF). The process of volatile release was analyzed, and the kinetic parameters of coal pyrolyzed in different conditions were also calculated. The results show that the H2 atmosphere and four kinds of catalysts promotes the weight loss of SF. There is apparentsynergistic effect when the addition proportion of 13X was 2%. From the results of dynamic calculation, the activation energy value was reduce in the condition of H2 atmosphere or adding 13X catalyst.The fluidization characteristic was studied by using self-built PPFB which the inner diameter is twenty five millimeters. The minimum fluidization velocity of quartz sand is 0.17m/s. With the increasing of fluidization velovity, the quality of semicokes in which a collection bottle increased. Under the micro fluidized bed, the distribution of semicoke in the bed material is less than 3% when the fluidizing gas velocity is at the speed of 0.340m/s. The fluidized state in good condition when the gas velocity increased from 0.25m/s to 0.34m/s.The effects of pyrolysis temperature, gas residence time, pyrolysis atmospheres and adding 13X catalyst were researched with PPFB. And the pyrolysis products distribution were investigated. The results show that the yield of char and pyrolysis gas decrease, the tar yield increases and reaches the maximum value at 650℃,12.29% with the pyrolysis temperature increased. With the increasing of gas residence time, the tar yield increases and then decreases, It reaches the maximum value at 1.25s. Compared with N2 atmosphere, H2 is the most influential factor on the tar yield, which is increased from 12.29% to 16.08%(daf).Adding the 13X catalyst was able to significantly increased the yield of BTX which increased by 144.7 percent than none of catalyst.The FTIR, BET, SEM were used to study the structural characteristics of semicokes. The result shows that the weight loss ratio of semicokes decrease with pyrolysis temperature increased or gas residence decreased. Because of the swelling deformation in the pyrolysis process, the specific surface area and pore size are smaller than that of raw coal.