Abstract: In the process of residue hydrogenation, the feed passes through the bed of protective catalyst and demetal catalyst in turn, intercepting mechanical impurities, removing most of the metal elements, and then enters the bed of transition catalyst and desulfurization catalyst. Carbon deposition is an important cause of inactivation of catalysts. The spent catalyst in long-term operated residue hydrogenation unit was collected, and the carbon deposition characteristics of the catalystswere investigated using a combination of thermogravimetric analysis and mass spectrometry. It was found that the burning temperature of deposited carbon increased significantly with the logistics direction, indicating that the carbon deposition formed on the catalyst gradually changed from soft carbon to hard carbon with the increase of residue hydrogenation depth along the logistics direction. The result of X-ray photoelectron spectroscopy analysis showed that the carbon deposits could be divided into C in the sp² form, sp³ form, and C in the C—O or C=O structure. The electron probe X-ray microanalysis showed that the distribution of carbon deposits on the catalyst was uniform.

Key words: residue hydrogenation, catalyst, carbon deposition, thermogravimetric analysis, mass spectrometry, X-ray photoelectron spectroscopy