Study On Reactivity Of Catalytic Pyrolysis Of Shenfu Coal In Different Reactive Gas

Preparation of light-tar and char with Shenfu coal by pyrolysis and char production have already become the pillar industry in north of Shaanxi Province. However, char production technology exists the disadvantages of low-heat value gas, low yield of tar and difficulty to control the quality of char. Therefore, the study of new pyrolysis technology of Shenfu coal has important theoretical and practical significance to raise the level of char technology in north of Shaanxi Province and improve the efficiency in the use of Shenfu coal.In this paper, catalytic pyrolysis of the coal (Shenfu No.3) behavior was investigated in the fixed bed reactor under different reactive atmosphere. The effect of transition metal oxides on the catalytic pyrolysis process was studied, and the suitable catalysts for catalytic pyrolysis of Shenfu coal under different reaction atmosphere(N2, H2, CH4, H2/CO) was selected.The influence of Fe2O3 and MnO2 catalysts on pyrolysis process of Shenfu coal was studied using thermogravimetric method, and the kinetics of Shenfu coal pyrolysis was researched. Fe2O3 and MnO2 have catalytication to pyrolysis of Shenfu coal. There are two temperature ranges (320⁵30℃and 656⁷45℃) of strong themal decomposition in catalytic pyrolysis.. The second peak position and the weight loss was only related with the been catalyst or not, and wasn't relevant to the oxide species. Catalytic pyrolysis of Shenfu coal with Fe2O3 and MnO2 consistent with the first-order kinetic, and the kinetic parameters activation energy E and frequency factor A exists compensation effect.Tar yield was increased from 3.98 % at 600℃to 8.03 % at 800℃, H2 yield was improved to 8.100mmol/g coal at 750℃from 0.414 mmol/g?coal at 600℃, under nitrogen atmosphere without catalyst. Tar yield generally was improved under H2, CH4 and H2/CO atmosphere. Thereinto, tar yield could reach to 8.35 % at 600℃, under methane atmosphere, the highest tar yield was 10.61 % which obtained at 700℃, yield of CO and CO2 decreased with the risesof temperature. H2 yield increased from 6.81mmol/g?coal at 650℃to8.145mmol/g?coal at 750℃. The highest tar yield was 10.97 % which obtained at 800℃,while CH4 yield was only 2.38 mmol/g?coal, and the highest CH4 yield was 6.853mmol/g?coal at 750℃, under H2 atmosphere. The highest tar yield was 8.80 % at 750℃, theyield of CO2 decreased to 1.058mmol/g?coal at 750℃from 3.502mmol/g?coal at 650℃,under synthesis gas atmosphereChar yield increased from 6.23% in 50mL/min of H2 to 15.31% in 200mL/min of H2under hydrogen atmosphere, without catalysts and at 750℃.Two component catalyst with different molar ratio (Fe2O3 and MnO2) were prepared bymechanical milling, and tri-component catalyst with different molar ratio (Fe2O3, MnO2 andMoO3) were prepared by coprecipitation. When MnO2 was added, tar yield up to 12.62%under hydrogen atmosphere at, and 13.42% under methane atmosphere at 750℃. WhenFe2O3 was added, tar yield can reach 12.99% under methane atmosphere. WhenM-Fe0.6/Mn0.6 was added, tar yield up to 13.01% under methane atmosphere. When additionof CP-Fe1/Mn0.2/Mo0.5 was added, tar yield can reach 11.00% under hydrogen atmosphere,and 10.48% under methane atmosphere.XRD of char showed that Fe2O3 existed in the form of Fe₃O₄ or Fe-C (Fe₂₃C₆) to thechar after coal pyrolysis, MnO₂ existed in the form of Mn²⁺ O to the char, MoO₃ was alsopresent in the form of carbide to the char.