柴油加氢反应器不同位置精制剂的失活分析

针对某炼油厂柴油加氢裂化装置停工换剂时发现加氢精制反应器床层顶部的精制剂表面覆盖垢物的现象,对不同位置的精制剂进行取样分析。对所取精制剂进行甲苯抽提、再生后采用比表面积及孔径分析仪、碳-硫分析仪（C-S）和扫描电子显微镜（SEM）等手段进行检测。结果表明：不同位置的失活精制剂上积炭量均较低,而比表面积等孔结构参数均显著降低,尤以装填位置靠上的精制剂更为明显,失活精制剂的再生效果均不理想;再生精制剂上出现磷酸铝特征衍射峰,精制剂表面沉积含磷、硅、铁和少量砷元素的无机物,或少量进入精制剂孔道,其是导致精制剂失活的主要原因,而且沿着物流自上而下的流向精制剂上杂质的沉积量逐渐减少,催化剂的失活程度减弱。

Deactivation analysis of hydrofining catalyst in different locations of diesel hydrogenation reactor

In view of the phenomenon that the surface of hydrofining catalyst on the top of hydrofining reactor was covered with scale when the diesel hydrocracking unit in a refinery was shut down,accompanied by replacing catalyst,the sampling analysis of hydrofining catalyst at different location was conducted.The specific surface area and aperture analyzer,carbon sulfur analyzer（C-S）,and scanning electron microscope（SEM） were carried out to analyze hydrofining catalyst after toluene extraction and regeneration.The results showed that the amount of carbon deposited on the deactivated catalyst at different location was relatively low,but the catalyst specific surface area and other pore structure parameters obviously decreased which was significantly lower near the top of hydrofining catalyst bed.The regeneration effect of hydrofining catalyst at different location was not ideal.The characteristic diffraction peak of AlPO₄ was appeared on the regenerated catalyst,and the inorganic impurities containing P,Si,Fe and little As elements deposited on the surface of hydrofining catalyst,or a little impurities diffused into catalyst channel,which was the main reason of catalyst deactivation.Along the top-down flow direction,the deposition of impurities on the hydrofining catalyst gradually decreased,and the deactivation degree of the hydrofining catalyst weakened.