Alternated fixed-bed residual oil hydrotreatment method and system

Abstract

The invention discloses an alternated fixed-bed residual oil hydrotreatment method and system. According to the method, a first hydropretreating reactor and a second hydropretreating reactor are in series connection to be served as online hydropretreating reactors, the first hydropretreating reactor is switched over and serves as a non-online hydropretreating reactor when pressure drop in the first hydropretreating reactor rises to a pressure drop design upper limit or the activity of a catalyst is lower than a required value, and then, switchover is carried out according to a sequence that the second hydropretreating reactor and a third hydropretreating reactor are connected in parallel, the third hydropretreating reactor and the first hydropretreating reactor are connected in parallel, and the first hydropretreating reactor and the second hydropretreating reactor are connected in series, so that the condition that two hydropretreating reactors are online simultaneously is achieved, and an uninterrupted hydropretreating reaction can be achieved. According to the method, the utilization efficiency of a main catalyst and the stability of device operation can be improved, and the operating time of a hydrotreating reactor is greatly prolonged.

Description

technical field [0001] The present invention relates to a fixed bed residual oil hydrogenation treatment method and system, in particular to a fixed bed residual oil hydrogenation treatment 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 pressure hydrogenation,...

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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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