Alternative residual oil hydrotreating-catalytic cracking combined process method and system

Abstract

The invention discloses a method and system for hydrogenation treatment of residual oil in a fixed bed which can be rotated. In the method, a hydroprocessing reaction zone, a hydroprocessing reaction zone and a catalytic cracking reaction zone are included; the hydroprocessing reaction zone includes first, second and third hydroprocessing reactors; the first, The second hydrogenation pretreatment reactor is connected in series as an online hydrogenation pretreatment reactor. When the pressure drop in the first hydrogenation pretreatment reactor rises to the design upper limit of the pressure drop or the catalyst activity is lower than the requirement, the first hydrogenation pretreatment reactor is cut off. Hydrogen pretreatment reactors, and then switch in the order of the second and third hydrogenation pretreatment reactors in parallel; the third and first hydrogenation pretreatment reactors in parallel; the first and second hydrogenation pretreatment reactors in series . The method can realize long running time without stoppage, and ensure reasonable and limited number of rotations, improve the utilization efficiency of the hydrotreating main catalyst and the stability of device operation, and greatly prolong the running time and work efficiency of the hydrotreating reactor.

Description

technical field [0001] The invention relates to a residual oil hydrotreating-catalytic cracking combined process method and system, in particular to a residue oil hydrotreating-catalytic cracking combined process method and system which can be rotated. Background technique [0002] As crude oil becomes heavier and worse, more and more heavy oil and residual oil need to be processed. The main purpose of the residue oil hydrotreating process is to greatly reduce the content of impurities such as sulfur, nitrogen, and metals in the residue oil raw material through hydrogenation treatment, and to convert non-ideal components such as polycyclic aromatics, colloids, and asphaltenes through hydrogenation. Increase the hydrogen-to-carbon ratio, reduce the residual carbon content, and significantly improve the cracking performance. [0003] Fixed bed residual oil hydrogenation technology is a deep processing technology for heavy oil. Under the condition of high temperature and high ...

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Problems solved by technology

However, after parallel and series operation, the method needs to stop and replace the catalysts of each hydrogenation pretreatment reactor, and requires a long shutdown time, and cannot continue hydrogenation of residual oil for a long time, thereby affecting the economic efficiency of the refinery; , the pressure drop of each hydrogenation pretreatment reactor is at the highest level in the late stage of operation, and it is also operated in series, which makes the total pressure drop of hydrogenation pretreatment very high. If the original operating conditions are maintained, it will affect the main The catalytic activity of the catalyst, this loss of catalytic activity is irreversible

In order to ensure the catalytic activity of the main catalyst, it is necessary to further increase the reaction severity of the front hydrogenation pretreatment and increase the reaction temperature to a greater extent, which will increase the load on the heating furnace. Sometimes the original design load may be too small to meet heating requirements

[0007] In the above residual oil hydrogenation process, when the fixed bed is filled with hydrogenation protecting agent and hydrodemetallization catalyst at the same time, if a lower proportion of hydrodemetallation agent is used, the hydrodemetallization performance of the entire catalyst system is insufficient, especially At the end of the operation, the metal-accommodating capacity is low, which leads to the rapid deactivation of the catalyst in the main reaction zone, which is not conducive to the long-term operation of the device; Insufficient scale and impurity capacity of the hydrogenation pretreatment reactor leads to a rapid rise in the pressure drop of the hydrogenation pretreatment reactor, shortens the normal operation time, and soon enters the end of operation, resulting in shutdown, which is also not conducive to the long-term operation of the device

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