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
After comparing the operating status of other catalytic reforming units and evaluation of the side-cut stream tests, the refinery investigated the influence of the feedstock property, clay types, and operating regime ...After comparing the operating status of other catalytic reforming units and evaluation of the side-cut stream tests, the refinery investigated the influence of the feedstock property, clay types, and operating regime of the clay tower and catalytic reforming unit on the service life of the clay. Test results had revealed that the low potential aromatic content of the reformer feed and high operating severity were the critical causes leading to high bromine number of the C8^＋ aromatics feed for the PX unit and the shortened service life of clay. This article also puts forward the corresponding remedial measures.展开更多
The adsorption process was studied for separating para-xylene from xylene mixture on modified nano-zeolite X in a breakthrough system. Nano-zeolitic adsorbent with different ratios of Si O2/Al2O3 was synthesized throu...The adsorption process was studied for separating para-xylene from xylene mixture on modified nano-zeolite X in a breakthrough system. Nano-zeolitic adsorbent with different ratios of Si O2/Al2O3 was synthesized through hydrothermal process and ion-exchanged with alkaline metal cations like lithium, sodium and potassium. The product was characterized by X-ray diffraction, scanning electron microscopy(SEM), nitrogen adsorption,transform electron microscopy(TEM) and in situ Fourier transform infrared(FTIR) spectroscopy. The influence of nano-zeolite water content and desorbent type on the selectivity of para-xylene toward other C8 aromatic isomers was studied. The optimization of adsorption process was also investigated under variable operation conditions. The isotherm for each isomer of C8 aromatics and the desorbents possess the adsorption characteristics of Langmuir type. The selectivity factor of para-xylene relative to each of meta-xylene, ortho-xylene and ethylbenzene under the optimum conditions obtained to be 5.36, 2.43 and 3.22, in the order given.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After comparing the operating status of other catalytic reforming units and evaluation of the side-cut stream tests, the refinery investigated the influence of the feedstock property, clay types, and operating regime of the clay tower and catalytic reforming unit on the service life of the clay. Test results had revealed that the low potential aromatic content of the reformer feed and high operating severity were the critical causes leading to high bromine number of the C8^＋ aromatics feed for the PX unit and the shortened service life of clay. This article also puts forward the corresponding remedial measures.
文摘The adsorption process was studied for separating para-xylene from xylene mixture on modified nano-zeolite X in a breakthrough system. Nano-zeolitic adsorbent with different ratios of Si O2/Al2O3 was synthesized through hydrothermal process and ion-exchanged with alkaline metal cations like lithium, sodium and potassium. The product was characterized by X-ray diffraction, scanning electron microscopy(SEM), nitrogen adsorption,transform electron microscopy(TEM) and in situ Fourier transform infrared(FTIR) spectroscopy. The influence of nano-zeolite water content and desorbent type on the selectivity of para-xylene toward other C8 aromatic isomers was studied. The optimization of adsorption process was also investigated under variable operation conditions. The isotherm for each isomer of C8 aromatics and the desorbents possess the adsorption characteristics of Langmuir type. The selectivity factor of para-xylene relative to each of meta-xylene, ortho-xylene and ethylbenzene under the optimum conditions obtained to be 5.36, 2.43 and 3.22, in the order given.
