柴油加氢保护剂杂质沉积分析

ANALYSIS ON IMPURITY OF GUARD CATALYST FROM DIESEL HYDROCRACKING PROCESS

收集了某炼油厂柴油加氢裂化装置顶部加氢保护剂,经甲苯抽提处理后,采用X射线衍射、X射线荧光光谱、碳-硫分析、N_(2)吸附-脱附、扫描电镜-能谱分析、热重-质谱分析等手段对保护剂样品进行表征,探讨床层压降升高的主要原因。结果表明:沿保护剂横截面,Si、P杂质均匀分布在保护剂的内部和外部,Ca、Fe杂质则主要沉积在保护剂的外表面;大量非金属Si、P,金属Fe、Ca及积炭等杂质的沉积,在保护剂外形成了一层“外壳”,使保护剂孔道被堵塞、外表面被覆盖,导致保护剂容纳杂质的能力明显降低,“外壳”的脱落最终导致床层压降不断升高。

Guard catalysts of the diesel hydrocracking unit in a refinery were collected and characterized by X-ray diffraction(XRD),X-ray fluorescence spectrum(XRF),carbon-sulfur analysis,thermogravimetry-mass spectrometry analysis(TG-MS),N_(2)adsorption-desorption and scanning electron microscopy with energy dispersive X-ray(SEM-EDX)after toluene extraction treatment.The results showed that along the cross section of the guard catalyst,the non-metallic impurities Si and P were evenly distributed in the interior and exterior of the guard catalyst,and the impurities Ca and Fe were mainly deposited on the outer surface of the guard catalyst.A large amount of Si,P,Fe,Ca,C and other impurities deposited and formed a“shell”over the guard catalyst,which blocked the pore channel and covered the outer surface of the catalyst,resulting in a significant reduction in the ability of containing impurities.The falling off of the“shell”eventually leads to the increasing pressure drop in the reactor.