A control system for high pressure hydrocracking system temporary removal of material in the device circulating

Abstract

The utility model discloses a kind of control systems of material device internal circulation when high-pressure hydrogenation fractionation system is temporarily removed, belong to petroleum refining and chemical equipment technical field, including first heating furnace, atmospheric tower, second heating furnace, vacuum tower, air cooler and sixth cut-off valve are connected in order through pipeline, one end of first circulation pipeline is communicated with inlet pipeline, other end is communicated with the pipeline of connecting vacuum tower and air cooler, one end of second circulation pipeline is communicated with the pipeline of connecting air cooler and sixth cut-off valve;First cut-off valve, guide valve, eight blind plate, second cut-off valve, third cut-off valve are sequentially arranged on first circulation pipeline, fourth cut-off valve is equipped on the inlet pipeline between first circulation pipeline and first heating furnace, fifth cut-off valve is equipped on the pipeline between first circulation pipeline and vacuum tower.The utility model can maintain catalyst activity, reduce equipment damage, can save cost and reduce energy consumption.

Description

Technical Field

[0001] This utility model belongs to the field of petroleum refining and chemical equipment technology, and more specifically relates to a control system for the internal circulation of materials in a high-pressure hydrogenation fractionation system when it is temporarily shut down. Background Technology

[0002] Currently, domestic high-pressure hydrogenation units for naphthenic distillate oils consist of two parts: a reaction system and a fractionation system. The main equipment in the reaction system includes reactors, heaters, heat exchangers, and high-pressure separators. Under high temperature, high pressure, and with the action of a catalyst, the naphthenic distillate oil undergoes a hydrogenation reaction with hydrogen, removing impurities from the feedstock oil through desulfurization, denitrification, deoxygenation, and reactions with saturated olefins and aromatics, thus improving oil quality. The main equipment in the fractionation system includes fractionation towers, reboilers, and condensers, which separate and purify the reaction products. Based on the different boiling points of each component, it separates them into different fractions to meet different application requirements. The reaction system and the fractionation system are integrated as a whole. The fractionation system needs to continuously separate reaction products. If the fractionation system needs to be shut down due to malfunction, maintenance, or process adjustments, traditional solutions require a complete shutdown, leading to decreased production efficiency, increased energy consumption, and frequent shutdowns that severely damage equipment and catalyst activity. Existing material circulation technologies for high-pressure hydrogenation units of cycloalkyl distillate oils are mostly designed for short-term circulation within the reactor, such as cold hydrogen systems. However, their function is limited to the reactor and cannot solve the problem of material balance and thermodynamic stability in the reaction system without shutting down the entire unit after the fractionation system is temporarily shut down.

[0003] Therefore, how to develop a control system for the internal circulation of materials in a high-pressure hydrogenation fractionation system when it is temporarily shut down is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0004] In view of this, the present invention provides a control system for the internal circulation of materials in the device when the high-pressure hydrogenation fractionation system is temporarily shut down.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A control system for the internal circulation of materials in a high-pressure hydrofractionation system during temporary shutdown includes a first heating furnace, a second heating furnace, an atmospheric pressure tower, a vacuum tower, an air cooler, a first circulation pipeline, a second circulation pipeline, and a first to a seventh shut-off valve.

[0007] The first heating furnace, the atmospheric pressure tower, the second heating furnace, the pressure reducing tower, the air cooler, and the sixth shut-off valve are connected in sequence via pipelines. The inlet of the first heating furnace is connected to an inlet pipeline. One end of the first circulation pipeline is connected to the inlet pipeline, and the other end is connected to the pipeline connecting the pressure reducing tower and the air cooler. One end of the second circulation pipeline is connected to the pipeline connecting the air cooler and the sixth shut-off valve. A seventh shut-off valve is installed on the second circulation pipeline.

[0008] The first circulation pipeline is sequentially equipped with a first shut-off valve, a drain valve, a figure-eight blind flange, a second shut-off valve, and a third shut-off valve. A fourth shut-off valve is provided on the inlet pipeline between the first circulation pipeline and the first heating furnace, and a fifth shut-off valve is provided on the pipeline between the first circulation pipeline and the pressure reducing tower.

[0009] The beneficial effects of this invention are as follows: In the event of a failure in the low-pressure fractionation system of a high-pressure hydrogenation unit, existing technologies involve a complete shutdown. This invention, by setting up a reaction system circulation pipeline, ensures that the reaction system continues uninterrupted and the material circulates within the high-pressure hydrogenation unit even when the fractionation system is temporarily shut down. Compared to existing technologies, this invention offers several advantages: First, it maintains catalyst activity. The circulating material keeps the catalyst in a suitable temperature, pressure, and material environment, preventing drastic temperature changes and contact with air caused by reaction system shutdown and material interruption. This prevents catalyst activity degradation or deactivation, facilitating rapid catalyst use when the unit resumes normal operation and ensuring stable reaction. Second, it reduces equipment damage by avoiding frequent start-ups and shutdowns. It prevents stress wear on seals and pipe connections due to significant temperature and pressure changes during start-ups and shutdowns, thus extending equipment lifespan. Third, it saves costs and reduces energy consumption. System start-ups and shutdowns require oil removal, replacement, and purging, consuming significant energy. The continuous material circulation and reaction system allow for faster recovery to normal production after maintenance. Compared to a complete shutdown and restart, this significantly shortens the unit's non-productive time, resulting in cost savings and energy reduction. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the control system structure for the internal circulation of materials in the high-pressure hydrogenation fractionation system of this utility model when it is temporarily shut down;

[0012] Among them, 1-first heating furnace, 2-second heating furnace, 3-atmospheric pressure tower, 4-pressure reducing tower, 5-air cooler, 6-first circulation pipeline, 7-inlet pipeline, 8-first shut-off valve, 9-drain valve, 10-figure-eight blind flange, 11-second shut-off valve, 12-third shut-off valve, 13-fourth shut-off valve, 14-fifth shut-off valve, 15-second circulation pipeline, 16-sixth shut-off valve, 17-seventh shut-off valve. Detailed Implementation

[0013] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0014] The control system for the internal circulation of materials in the high-pressure hydrofractionation system when it is temporarily shut down includes a first heating furnace 1, a second heating furnace 2, an atmospheric pressure tower 3, a vacuum tower 4, an air cooler 5, a first circulation pipeline 6, a second circulation pipeline 15, and a first shut-off valve 8 to a seventh shut-off valve 17.

[0015] The first heating furnace 1, the atmospheric pressure tower 3, the second heating furnace 2, the pressure reducing tower 4, the air cooler 5, and the sixth shut-off valve 16 are connected in sequence via pipelines. The inlet pipe 7 is connected to the inlet of the first heating furnace 1. One end of the first circulation pipe 6 is connected to the inlet pipe 7, and the other end is connected to the pipeline connecting the pressure reducing tower 4 and the air cooler 5. One end of the second circulation pipe 15 is connected to the pipeline connecting the air cooler 5 and the sixth shut-off valve 16. A seventh shut-off valve 17 is installed on the second circulation pipe 15.

[0016] The first circulation pipeline 6 is sequentially equipped with a first shut-off valve 8, a drain valve 9, a figure-eight blind flange 10, a second shut-off valve 11, and a third shut-off valve 12. The inlet pipeline 7 between the first circulation pipeline 6 and the first heating furnace 1 is equipped with a fourth shut-off valve 13. The pipeline between the first circulation pipeline 6 and the pressure reducing tower 4 is equipped with a fifth shut-off valve 14.

[0017] The working principle of the control system for material circulation within the high-pressure hydrotreating fractionation system during temporary shutdown: Existing high-pressure hydrotreating units for cycloalkyl distillate oils consist of two parts: a reaction system and a fractionation system. When a sudden situation arises requiring temporary shutdown of the fractionation system, firstly, the figure-eight blind flange 10 on the first circulation pipeline 6 is reversed to ensure the first circulation pipeline 6 is open. Then, the fourth shut-off valve 13 on the inlet pipeline 7 is closed, followed by the fifth shut-off valve 14 and the sixth shut-off valve 16 (valve for bottom oil exiting the high-pressure hydrotreating unit). The seventh shut-off valve 17 (valve for bottom oil entering the second circulation pipeline) is opened. Then, the first shut-off valve 8, the second shut-off valve 11, and the third shut-off valve 12 are opened sequentially, while the drain valve 9 remains closed. At this time, all the material in the reaction system will enter the first circulation pipeline 6, be further cooled by the air cooler 5, and then enter the second circulation pipeline 15, returning to the reaction system. This ensures that the material does not exit the high-pressure hydrotreating unit but circulates within the reaction system. When the fractionation system returns to normal, open the fourth shut-off valve 13 on the inlet pipe 7, open the fifth shut-off valve 14, and then sequentially close the first shut-off valve 8, the second shut-off valve 11, the third shut-off valve 12 on the first circulation pipe, close the seventh shut-off valve 17, open the sixth shut-off valve 16, open the drain valve 9, drain the oil stored in the first circulation pipe 6 which is in the closed state, and then turn the figure-eight blind flange 10 to disconnect the first circulation pipe 6 from the entire high-pressure hydrogenation unit.

[0018] The description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control system for the internal circulation of materials in a high-pressure hydrofractionation system during temporary shutdown, characterized in that, It includes a first heating furnace, a second heating furnace, an atmospheric pressure tower, a vacuum pressure tower, an air cooler, a first circulation pipeline, a second circulation pipeline, and first to seventh shut-off valves; The first heating furnace, the atmospheric pressure tower, the second heating furnace, the pressure reducing tower, the air cooler, and the sixth shut-off valve are connected in sequence via pipelines. The inlet of the first heating furnace is connected to an inlet pipeline. One end of the first circulation pipeline is connected to the inlet pipeline, and the other end is connected to the pipeline connecting the pressure reducing tower and the air cooler. One end of the second circulation pipeline is connected to the pipeline connecting the air cooler and the sixth shut-off valve. A seventh shut-off valve is installed on the second circulation pipeline. The first circulation pipeline is sequentially equipped with a first shut-off valve, a drain valve, a figure-eight blind flange, a second shut-off valve, and a third shut-off valve. A fourth shut-off valve is provided on the inlet pipeline between the first circulation pipeline and the first heating furnace, and a fifth shut-off valve is provided on the pipeline between the first circulation pipeline and the pressure reducing tower.

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