The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technolo...The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technological route at the plant.The comparison reveals differences in every aspect of feed consumption,unit capacity,product output,product distribution,and unit process parameters depending upon which catalyst type is adopted by the integrated PX complex.The type of aromatics isomerization catalyst has its influence on the plant scale,the construction cost,the process unit capacity and the product cost,with the magnitude of its impact varying with changing feed conditions.展开更多
HMCM-22 catalysts modified with La203 （5% La） and MgO （≈0.87% Mg） were prepared respectively by impregnation method, and were characterized by scanning electron microscopy, X-ray diffraction, N2 physical ad- sorp...HMCM-22 catalysts modified with La203 （5% La） and MgO （≈0.87% Mg） were prepared respectively by impregnation method, and were characterized by scanning electron microscopy, X-ray diffraction, N2 physical ad- sorption-desorption and temperature-programmed desorption of NH3. The effect of supported metallic oxides （La203, MgO） on catalytic performance in xylene isomerization of C8 aromatics （ethylbenzene, m-xylene and o-xylene） was investigated in detail. The experimental results showed that 5% LaJHMCM-22 catalyst had higher isomerization activity and stronger shape-selectivity than 0.87% Mg/HMCM-22 catalyst, owing to its more acid sites and smaller pore size. And the loading amount of La was optimized to be about 7%. Moreover, supporting metal over 7% La/HMCM-22, respectively with 0.3% Pt, 3% Ni and 3% Mo, was carried out to prepare bifunction- al isomerization catalysts. In comparison, 3% Mo/7% La/HMCM-22 showed the best catalytic performance with both high activity and high selectivity, with the low hydrocracking of m-xylene and o-xylene. Besides, the op- timal reaction conditions were found： 340℃, 1.5 MPa H2, WHSV 4 h^-1 and H2/C8 4 mol/mol. Under the above conditions, ethylbenzene conversion was up to 20%, para-selectivity was over 23% with low xylene loss of 2.9%.展开更多
文摘The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technological route at the plant.The comparison reveals differences in every aspect of feed consumption,unit capacity,product output,product distribution,and unit process parameters depending upon which catalyst type is adopted by the integrated PX complex.The type of aromatics isomerization catalyst has its influence on the plant scale,the construction cost,the process unit capacity and the product cost,with the magnitude of its impact varying with changing feed conditions.
文摘HMCM-22 catalysts modified with La203 （5% La） and MgO （≈0.87% Mg） were prepared respectively by impregnation method, and were characterized by scanning electron microscopy, X-ray diffraction, N2 physical ad- sorption-desorption and temperature-programmed desorption of NH3. The effect of supported metallic oxides （La203, MgO） on catalytic performance in xylene isomerization of C8 aromatics （ethylbenzene, m-xylene and o-xylene） was investigated in detail. The experimental results showed that 5% LaJHMCM-22 catalyst had higher isomerization activity and stronger shape-selectivity than 0.87% Mg/HMCM-22 catalyst, owing to its more acid sites and smaller pore size. And the loading amount of La was optimized to be about 7%. Moreover, supporting metal over 7% La/HMCM-22, respectively with 0.3% Pt, 3% Ni and 3% Mo, was carried out to prepare bifunction- al isomerization catalysts. In comparison, 3% Mo/7% La/HMCM-22 showed the best catalytic performance with both high activity and high selectivity, with the low hydrocracking of m-xylene and o-xylene. Besides, the op- timal reaction conditions were found： 340℃, 1.5 MPa H2, WHSV 4 h^-1 and H2/C8 4 mol/mol. Under the above conditions, ethylbenzene conversion was up to 20%, para-selectivity was over 23% with low xylene loss of 2.9%.
