WO2018177400A1 - Temperature and pressure control method for hydrogenation process, design method therefor and use thereof - Google Patents

Abstract

Disclosed are a temperature and pressure control method for a hydrogenation process, a design method therefor and the use thereof. A pressure relief point is arranged at an outlet of a separation system after a reactor, or at a downstream device or pipeline connected thereto, with the temperature at the pressure relief point being 30-220C. Two control points are arranged, wherein when control point I is exceeded, i.e., temperature 440C /pressure 19 MPa, the pressure reduction rate is 3-10 bar/min; and when control point II is exceeded, i.e., temperature 460C /pressure 21 MPa, the pressure reduction rate is 10-25 bar/min. By using this control method, a high-pressure device can be made more stable during a pressure relief process.

Description

Temperature and pressure control method of hydrogenation process, design method and use thereof Technical field

The invention relates to a temperature and pressure control method for a hydrogenation process, a design method thereof and a use thereof, and belongs to the fields of petrochemical industry and coal chemical industry.

Background technique

The slurry bed hydrogenation process can effectively utilize heavy oil resources and coal resources, remove impurities such as sulfur, nitrogen and heavy metals from raw materials, and improve the yield and quality of light oil, posing challenges to traditional refining technologies. At the same time, due to its low price, and thus improve the economic benefits of processing enterprises, the slurry bed processing technology has become a research hotspot in the petrochemical industry in recent years. The slurry bed hydrogenation reactor is the core equipment of the process and is related to the success of the entire plant operation.

The hydrogenation reaction is a strong exothermic reaction, the temperature rise in the reactor is high, and the slurry bed hydrogenation process is complicated, which makes the possibility of overheating and overpressure of the reactor greatly increased, so the reactor must be overtempered and super The pre-judgment of the working conditions is made, and safety measures to prevent overheating and overpressure of the reactor are made.

After the raw material is heated by the heating furnace and then enters the hydrogenation reactor, the improper operation of the heating furnace, the unstable feed of the reactor, the blockage of the outlet of the reactor, and the failure of the circulation operation in the slurry bed reactor may cause the reactor to fly or exceed the temperature. Pressure, once this condition occurs, the temperature and pressure of the reactor may continue to rise, which will aggravate the light oil cracking reaction, on the one hand, the light oil yield is lost, and on the other hand, the pressure in the reactor is sharply increased; In addition, the occurrence of polycondensation reaction will be aggravated, resulting in blockage of equipment. Once the above situation occurs, emergency treatment is required. The most effective method is to terminate the reaction: 1. Cut off the raw material and hydrogen supply; 2. Separate the gas and liquid phases in the reactor, that is, separate the hydrogen and oil phases in the reactor, and terminate. Hydrogenation reaction; 3. Discharge the superheated medium in the reactor in time, and reduce the pressure in the reactor. However, the above step 3 is a difficult point to deal with the flying temperature and overpressure, and there is no good solution at present.

Summary of the invention

The invention provides a temperature and pressure control method for a hydrogenation process, a design method thereof and a use thereof, and is used for treating an emergency condition such as a flying temperature or an overpressure of a reactor. The pressure and temperature in the reactor are reduced to a reasonable interval by selecting the appropriate pressure relief point and pressure relief rate.

The technical solutions are as follows:

A temperature and pressure control method for a hydrogenation process, characterized in that a pressure relief point is provided on an outlet of a separation system after the reactor or a downstream equipment or pipeline connected thereto, and the pressure in the reaction system is gradually released by opening a pressure relief point Wherein the temperature at the pressure relief point is 30 ° C to 220 ° C, two control points are set in order from low to high, and the pressure reduction rate is 3-10 bar/min when the control point is exceeded; The pressure rate is 10-25 bar/min, and the control point is: temperature ≥ 440 ° C and / or pressure ≥ 19 MPa, control point 2: temperature ≥ 460 ° C and / or pressure ≥ 21 MPa.

Preferably the control point is located at the outlet of the cryogenic high pressure separator.

Preferably the control point is in communication with the reaction system.

Preferably, the buck speed of the control point is controlled by a valve, and the valve is automatically and/or manually controlled.

The number of preferred pressure relief valves is ≥1, which is used in parallel when more than one is used.

The preferred discharge medium is sent to the flare system.

The preferred temperature control system accepts other emergency status signals in addition to the monitoring point pressure signal.

After the preferred pressure relief is initiated, a signal is sent to the device control system.

Preferably, the reaction material entering the apparatus is cut off after the control point is exceeded.

The use of the temperature and pressure control method of the foregoing hydrogenation process is characterized in that it is used in a heavy oil hydrogenation process or a coal-fired hydrotreated slurry bed hydrogenation process, and the heavy oil hydrogenation process refers to a residue oil and a catalytic oil slurry. One or more combinations of deoiled asphalt and coal tar are processed as raw materials; the oil coal slurry bed hydrogenation process refers to one of crude oil, residual oil, catalytic oil slurry, deoiled asphalt and coal tar Or a plurality of combinations are processed together with one or more of lignite and bituminous coal as raw materials, and the weight ratio of oil to coal ranges from 30 to 97:70-3.

The foregoing method for designing a temperature and pressure control method for a hydrogenation process.

Effect of the invention

The invention provides a set of emergency treatment measures such as over-temperature and over-pressure of the hydrogenation reaction system, and after the separator, especially after the cold high score, the pressure relief point is set, and the reactor is designed by designing a new idea of the pressure relief rate and the steps. High-pressure equipment such as high-pressure separators can be made more stable during the pressure relief process.

After the cold high score is set, the control point is gradually released, the pressure in the reaction system is gradually released by opening the control point, the reaction pressure is lowered, the reaction heat is taken out, the reaction speed is gradually reduced, and finally the reaction temperature is lowered to achieve a reasonable temperature drop rate. First, it can ensure that the temperature and pressure of the reactor are reduced to a reasonable operating range or stop working; the second is to ensure that the high-pressure equipment such as the reactor and the high-pressure separator, as well as the pipelines and valves, are not subjected to excessive pressure shock during the pressure relief process. The role of the protection equipment; the third is the cold high-level discharge medium is cold and clean gas phase material, can be directly discharged to the flare system, without additional special flare system, reducing operational risks and investment.

The control point is in communication with the reaction system, ie the pressure detected by the control point can truly reflect the pressure within the reactor.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a reactor according to an embodiment of the present invention, and the numbers in the figures are listed as follows:

1-Hot high score, 2-temperature high score, 3-cold high score, 4-hot low score, 5-temperature low score, 6-cold low score, 7-reaction product, 8-cold oil, 9-vent Pressure line, 10-cold high fraction gas phase product, 11-cold low fraction gas phase product, 12-cold low fraction liquid phase product, 13-wastewater, 14-warm low oil phase product, 15-reactor.

detailed description

In order to further illustrate the specific features of the present invention, it will be described in conjunction with FIG. 1. This example describes a pressure relief process for a hydrogen coal slurry bed (with internal circulation structure) hydrogenation process, including a connection mode as shown in FIG. Reactor 15, hot high score 1, warm high score 2, cold high score 3, hot low score 4, warm low score 5, cold low score 6, the materials indicated in the various stages in the figure are reaction product 7, cold oil 8. Pressure relief line 9, cold high fraction gas phase product 10, cold low fraction gas phase product 11, cold low fraction liquid phase product 12, wastewater 13, warm low oil phase product 14.

The pressure relief point is set at the cold high score 3 outlet, which is valve A and valve B, which are arranged in parallel. The valve is a two-position valve with a pressure relief rate of 6 bar/min and 15 bar/min respectively.

When the reactor 15 is operating normally, the outlet operating temperature does not exceed 455 ° C, the pressure does not exceed 19 MPa, because the hydrocracking reaction is an exothermic reaction, in order to avoid the failure state of the thermometer or the sensor, three thermometers are set, in accordance with the method of taking two Read temperature, when the operating temperature exceeds 455 °C, start the pressure relief valve A, the pressure relief speed is 6bar / min, if the temperature in the reactor 1 continues to rise, exceeds 465 ° C, then open the valve B, the total pressure relief rate At 21 bar/min, two pressure relief valves are used at the same time.

There is no valve between the outlet of the reactor 15 and the outlet of the cold high score 3 to ensure that the cold high score 3 is connected to the reactor 15. The pressure signal of the pressure relief valve is taken from the front of the valve, where the pressure difference between the pressure and the reactor is fixed. So the pressure here can actually react to the pressure inside the reactor. When the reactor 15 is operating normally, the operating pressure does not exceed 20 MPa. In order to avoid the failure state of the pressure gauge or the sensor, three pressure gauges are set, and the pressure is read in accordance with the method of three-take two. When the operating pressure exceeds the pressure when the pressure exceeds 20 MPa, The pressure relief valve A is opened and the pressure relief speed is 6 bar/min. If the pressure in the reactor continues to increase, exceeding 22 MPa, the valve B is also opened, and the total pressure relief speed is 21 bar/min, and the two pressure relief valves are used at the same time.

Stop the coal slurry and hydrogen feed before the pressure is released, and shut down the reactor circulation pump to cut off the reaction.

According to the above embodiment, the use of the pressure relief method of the present invention has achieved good application effect in the coal-fired slurry bed hydrogenation process, and the operation is simple, and the degree of automation is high, and the production is improved. safety.

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present invention. All should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims (9)

A temperature and pressure control method for a hydrogenation process, characterized in that a pressure relief point is provided on an outlet of a separation system after the reactor or a downstream equipment or pipeline connected thereto, and the pressure in the reaction system is gradually released by opening a pressure relief point Wherein the temperature at the pressure relief point is 30 ° C to 220 ° C, two control points are set in order from low to high, and the pressure reduction rate is 3-10 bar/min when the control point is exceeded; The pressure rate is 10-25 bar/min, the control point is: temperature ≥ 440 ° C and / or pressure ≥ 19 MPa, control point 2: temperature ≥ 460 ° C and / or pressure ≥ 21 MPa. The method of claim 1 wherein said control point is disposed at a low temperature, high pressure separator outlet. The method of claim 1 wherein the pressure drop rate of said pressure relief point is controlled by a valve and the valve is automatically and/or manually controlled. The method of claim 1 wherein the number of pressure relief valves is > 1 and is used in parallel when more than one is used. The method of claim 1 wherein the discharge medium is delivered to the flare system. The method of claim 1 wherein the signal is sent to the device control system after the pressure relief is initiated. The method of claim 1 wherein the reaction material entering the apparatus is severed prior to reaching the control point. The use of the method according to any one of claims 1 to 7, characterized in that it is used in a heavy oil hydrogenation process or a petrochemical hydrogenation slurry bed hydrogenation process, and the heavy oil hydrogenation process refers to a residue oil, a catalytic oil slurry, and a desulfurization process. One or more combinations of oil pitch and coal tar are processed as raw materials; the oil coal slurry bed hydrogenation process refers to one or more of crude oil, residual oil, catalytic oil slurry, deoiled asphalt and coal tar The combination is processed with one or more of lignite and bituminous coal as raw materials, and the weight ratio of oil to coal ranges from 30 to 97:70-3. A method for designing a temperature and pressure control method for a hydrogenation process, characterized in that a pressure relief point is set on an outlet of a separation system after the reactor or a downstream device or pipeline connected thereto, and the reaction is gradually released by opening the pressure relief point The pressure in the system, wherein the temperature at the pressure relief point is 30 ° C ~ 220 ° C, two control points are set in order from low to high, and the pressure drop rate is 3-10 bar / min when the control point is exceeded; At 2 o'clock, the pressure drop rate is 10-25 bar/min, and the control point is: temperature ≥ 440 ° C and / or pressure ≥ 19 MPa, control point 2: temperature ≥ 460 ° C and / or pressure ≥ 21 MPa.

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