裂解汽油中噻吩硫在Co-Mo/Al_2O_3上的催化加氢宏观动力学

Macrokinetics for catalytic hydrogenation of thiophenic sulfides in pyrolysis gasoline over Co-Mo/Al_2O_3 catalyst

采用绝热管式固定床积分反应器,在2.5MPa^3.9MPa、513K^655K、氢/裂解汽油摩尔比1.8~3.5和裂解汽油中噻吩、单甲基噻吩和双甲基噻吩质量分数为838×10-6、137×10-6~723×10-6和192×10-6~723×10-6下,对Co-Mo/Al2O3催化剂上裂解汽油催化加氢脱硫的宏观动力学进行了研究。以Powell优化法和Merson迭代法对动力学实验数据进行非线性参数估值,建立了良好吻合实验数据的、裂解汽油催化加氢脱硫的幂函数型宏观动力学模型。噻吩、单甲基噻吩和双甲基噻吩的反应级数分别为0.721、0.735和0.87,对应的加氢反应宏观活化能依次为70.0kJ·mol-1、67.9kJ·mol-1和59.9kJ·mol-1。各噻吩基硫的转化率均随反应压力的提高而增加,3.5MPa以上时,增加的趋势减缓;反应温度的提高有利于噻吩基硫转化率的增加;593K以上时,各硫化物的转化率随温度的增加呈现线性增加的趋势。

The macro-kinetic investiqations for catalytic hydrodelsulfurization of pyrolysis gasoline over an industrial Co-Mo/Al2O3 catalyst were carried out in an adiabatic tubular fixed-bed reactor under the conditions： 2.5 MPa -3.9 MPa, 513 K -655 K, H2/pyrolysis-gasoline molar ratio 1.8 -3.5, and the mass concentration of thiophene, methylthiophene and dimethylthiophene in the feed pyrolysis-gasoline, 838 × 10^-6, 137 × 10^-6 723 × 10^-6 and 192 × 10^-6 - 723 × 10^ -6, respectively. By means of Powell optimal method and Merson integral method, the power-law type macro-kinetic models for the catalytic hydrodelsulfurization of pyrolysis gasoline were developed. The reaction orders of thiophene, methylthiophene and dimethylthiophene are 0. 721, 0. 735 and 0.870, respectively, and the activation energies are 70.0 kJ·mol^- 1, 67.9 kJ·mol^- 1 and 59.9 kJ · mol^- 1 respectively. The conversion of thiophenic sulfides increases with the reaction pressure, but this increase is obviously slowed down at the reaction pressure above 3.5 MPa. The increase of reaction temperature is beneficial to the conversion enhancement of thiophenic sulfides, especially above 563 K. When the reaction temperature increases above 593 K, the correlation between the conversion of thiophenic sulfides and temperature is almost linear. Therefore, for the Co-Mo/Al2O3 catalyst used, the favorable operating pressure is about 3.5 MPa, and the reaction temperature should be higher than 593 K.