A hydrogenation reaction system and its multifunctional control mechanism

Abstract

This invention belongs to the field of chemical equipment technology, specifically relating to a hydrogenation reaction system and its multifunctional control mechanism. The hydrogenation reaction system includes a hydrogenation settling tank, a benzene storage tank, a high-purity water storage tank, a hydrogen storage tank, and a first hydrogenation reactor and a second hydrogenation reactor. The first hydrogenation reactor has a first overflow weir, and the second hydrogenation reactor has a second overflow weir. The multifunctional control mechanism of the hydrogenation reaction system includes an angle valve, a double-acting valve positioner, an actuator, and control accessories. The control accessories include a first pneumatic directional valve, a second pneumatic directional valve, and a gas storage tank. This invention, through the design of the connection structure of the angle valve, double-acting valve positioner, actuator, and control accessories, regulates the material discharge from the hydrogenation reaction system under different conditions, avoiding interference with the post-processing system, thereby improving system safety and ensuring the safe conduct of the hydrogenation reaction.

Description

Technical Field

[0001] This invention belongs to the field of chemical equipment technology, specifically relating to a hydrogenation reaction system and its multifunctional control mechanism. Background Technology

[0002] Cyclohexanol is a widely used chemical raw material and solvent. It can undergo a dehydration reaction at high temperatures (150℃~300℃) to produce cyclohexene. Among its many uses, the most important is cyclohexanone, a key intermediate in the production of nylon 6 and nylon 66.

[0003] The cyclohexanol production unit includes equipment in five main sections: hydrogen desulfurization, benzene hydrogenation, extractive distillation, hydration, and cyclohexane refining. The benzene hydrogenation section includes a benzene pretreatment unit, a hydrogen compression unit, a hydrogenation reaction unit, and a hydrogen separation unit. Its main purpose is to partially hydrogenate benzene to produce cyclohexene or completely hydrogenate it to produce cyclohexane in the hydrogenation reactor.

[0004] During hydrogenation reactions, when process materials require heating or cooling, jackets can be installed on the reactor walls, or heat exchange surfaces can be installed inside the reactor. External circulation can also be used for heat exchange. Commonly used reactor types include tubular reactors, batch reactors, solid particle bed reactors, tower reactors, and jet reactors. Among these, solid particle bed reactors utilize gas and / or liquid passing through a fixed or moving solid particle bed to achieve a multiphase reaction process. Because this process involves high temperature and high pressure conditions, there are risks of flammability and explosion. Improper handling can damage equipment used in post-hydrogenation processing (such as hydrogenation flash tanks). Therefore, process safety control of the reactor is particularly important.

[0005] In the design of chemical reactors, the automatic control system should typically be considered from three aspects: quality indicators, material balance, and constraints. Compared to other chemical unit operation equipment, the operational safety of hydrogenation reactors and their post-processing systems is of paramount importance. Therefore, to prevent process variables from entering hazardous areas or causing abnormal operating conditions, and to avoid impacting the post-processing system, alarm, interlock, and selective control devices adapted to the hydrogenation reactor should be designed to ensure system safety. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to propose a hydrogenation reaction system and its multifunctional control mechanism. By designing a connection structure for an angle valve, a double-acting valve positioner, an actuator, and control accessories, the system can regulate the material discharge from the hydrogenation reaction system under different conditions, thereby preventing the post-processing system from being affected, improving system safety, and ensuring the safe conduct of the hydrogenation reaction.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A hydrogenation reaction system includes a hydrogenation settling tank, a benzene storage tank, a high-purity water storage tank, a hydrogen storage tank, a first hydrogenation reactor, and a second hydrogenation reactor.

[0009] The first hydrogenation reactor is equipped with a first overflow weir, and the second hydrogenation reactor is equipped with a second overflow weir;

[0010] The benzene storage tank is connected to the first hydrogenation reactor via the first feed pipe, the high-purity water storage tank is connected to the first feed pipe via a pipeline, and the hydrogen storage tank is connected to the first hydrogenation reactor via the first gas inlet pipe; the connection end of the first feed pipe to the first hydrogenation reactor and the connection end of the first gas inlet pipe to the first hydrogenation reactor are both lower than the first overflow weir.

[0011] The first hydrogenation reactor is connected to the second hydrogenation reactor via the first discharge pipe, and the hydrogen storage tank is connected to the second hydrogenation reactor via the second inlet pipe; the connection end of the first discharge pipe to the first hydrogenation reactor is higher than the first overflow weir, and the connection end of the first discharge pipe to the second hydrogenation reactor is lower than the second overflow weir; the connection end of the second inlet pipe to the second hydrogenation reactor is lower than the second overflow weir.

[0012] The second hydrogenation reactor is connected to the top inlet of the hydrogenation settling tank via the second discharge pipe. The bottom of the hydrogenation settling tank is provided with a third discharge pipe. The first hydrogenation reactor is connected to the third discharge pipe via a return pipe. The connection end of the return pipe to the first hydrogenation reactor is lower than the first overflow weir.

[0013] Furthermore, the first overflow weir includes a first horizontal section, a first vertical section, and a second horizontal section. The top end of the first vertical section is connected to the right end of the first horizontal section, the bottom end of the first vertical section is connected to the left end of the second horizontal section, and the right end of the second horizontal section is connected to the right side wall of the first hydrogenation reactor; that is, the second horizontal section is lower than the first horizontal section in the horizontal direction.

[0014] Furthermore, the second overflow weir includes a third horizontal section, a second vertical section, and a fourth horizontal section. The top end of the second vertical section is connected to the right end of the third horizontal section, the bottom end of the second vertical section is connected to the left end of the fourth horizontal section, and the right end of the fourth horizontal section is connected to the right side wall of the second hydrogenation reactor; that is, the fourth horizontal section is lower than the third horizontal section in the horizontal direction.

[0015] More preferably, the connection end between the first discharge pipe and the first hydrogenation reactor is lower than the first horizontal section and higher than the second horizontal section.

[0016] More preferably, the connection end between the second discharge pipe and the second hydrogenation reactor is lower than the third horizontal section and higher than the fourth horizontal section.

[0017] Furthermore, the first feed pipe is equipped with a first control valve and a first feed pump, which are used to control the entry of benzene and high-purity water into the first hydrogenation reactor.

[0018] Furthermore, the first intake pipe is equipped with a second control valve and a first intake pump; the second intake pipe is equipped with a second control valve and a second intake pump; these are used to control the amount of hydrogen entering the first hydrogenation reactor and the second hydrogenation reactor, respectively.

[0019] Furthermore, a fourth control valve and a catalyst slurry circulation pump are installed on the return pipe to control the entry of the catalyst slurry into the first hydrogenation reactor.

[0020] Furthermore, the return pipe is also equipped with a post-processing discharge pipe. The reaction products are separated by settling in the hydrogenation settling tank and then sent to the post-processing system through the post-processing discharge pipe.

[0021] Furthermore, based on a general inventive concept, the present invention also provides a multifunctional control mechanism for the hydrogenation reaction system, including an angle valve, a double-acting valve positioner, an actuator, and control accessories; the control accessories include a first pneumatic directional valve, a second pneumatic directional valve, and a gas storage tank;

[0022] The first pneumatic directional valve has a first gas input end, a second gas input end, and a first gas output end, with the second input end closed; the second pneumatic directional valve has a third gas input end, a fourth gas input end, and a second gas output end.

[0023] Both the first pneumatic directional valve and the second pneumatic directional valve are equipped with a directional switch, and the directional switch is equipped with a pneumatic input end; the directional switch on the first pneumatic directional valve can switch the connection between the first gas input end and the first gas output end or the connection between the second gas input end and the first gas output end; the directional switch on the second pneumatic directional valve can switch the connection between the third gas input end and the second gas output end or the connection between the fourth gas input end and the second gas output end.

[0024] An external air source is connected to the pneumatic input terminal of the commutator on the first pneumatic directional valve and the second pneumatic directional valve respectively through the first air supply pipe. A solenoid valve is provided on the first air supply pipe.

[0025] The double-acting valve positioner can realize the access and exit of the air path. The external air source is connected to the first air inlet of the double-acting valve positioner through the second air supply pipe.

[0026] The double-acting valve positioner is equipped with two gas output pipes, namely the third gas supply pipe and the fourth gas supply pipe. The third gas supply pipe is connected to the first gas input end, and the fourth gas supply pipe is connected to the fourth gas input end.

[0027] The actuator includes an upper air chamber and a lower air chamber. The upper air chamber is provided with a first transverse partition, which divides the upper air chamber into a first upper chamber and a first lower chamber. The lower air chamber is provided with a second transverse partition, which divides the lower air chamber into a second upper chamber and a second lower chamber.

[0028] The first diaphragm can slide up and down in the upper air chamber, and the second diaphragm can slide up and down in the lower air chamber;

[0029] The first gas output terminal has two branches, one of which is connected to the first lower chamber and the other of which is connected to the second lower chamber. The second gas output terminal has two branches, one of which is connected to the first upper chamber and the other of which is connected to the second upper chamber.

[0030] The actuator also includes a first link, a second link, and a transmission rod disposed outside the actuator; the first link connects the first transverse partition to the transmission rod, the second link connects the second transverse partition to the transmission rod, and the movement of the first and second transverse partitions up and down drives the transmission rod, the first link, and the second link to move up and down.

[0031] Angle valve includes a valve core chamber, an input end, and an output end. The valve core chamber contains a valve core, which divides the valve core chamber into upper and lower chambers. The valve core can control the opening and closing of the input end and the output end of the angle valve. The bottom end of the transmission rod is connected to the valve core, and the transmission rod can drive the valve core to move up and down relative to the valve core chamber.

[0032] Specifically, the angle valve is installed on the aftertreatment discharge pipe.

[0033] Specifically, the first gas input terminal is located on the right side of the first pneumatic directional valve, the second gas input terminal is located below the first pneumatic directional valve, and the first gas output terminal is located on the left side of the first pneumatic directional valve.

[0034] Specifically, the third gas input terminal is located to the right of the second pneumatic directional valve, the fourth gas input terminal is located below the second pneumatic directional valve, and the second gas output terminal is located to the left of the second pneumatic directional valve.

[0035] Specifically, a position-holding valve is also installed on the first gas pipeline.

[0036] Specifically, a filter pressure reducing valve is installed on the second gas supply pipe.

[0037] Specifically, the third gas pipe is equipped with a first pneumatic power amplifier, and the fourth gas pipe is equipped with a second pneumatic power amplifier.

[0038] Specifically, the second gas pipeline is also equipped with a first branch pipe, which is connected to the third gas input terminal.

[0039] Specifically, the lower air chamber is located at the bottom of the upper air chamber.

[0040] Specifically, the first transverse partition is provided with a first sliding member at both the left and right ends. The left end of the first transverse partition is connected to the left side wall of the actuator through the first sliding member, and the right end of the first transverse partition is connected to the right side wall of the actuator through the first sliding member. The first sliding member can enable the first transverse partition to slide up and down in the upper air chamber.

[0041] Specifically, the second diaphragm is provided with a second sliding member at both the left and right ends. The left end of the second diaphragm is connected to the left side wall of the actuator through the second sliding member, and the right end of the second diaphragm is connected to the right side wall of the actuator through the second sliding member. The second diaphragm can slide up and down in the lower air chamber through the second sliding member.

[0042] Specifically, the first link, the second link, and the transmission rod are located at the front of the actuator, and both the first link and the second link extend in the front-rear direction; the rear end of the first link is connected to the first transverse partition, the front end of the first link is connected to the upper part of the transmission rod, the rear end of the second link is connected to the second transverse partition, and the front end of the first link is connected to the upper part of the transmission rod. The transmission rod, the first link, and the second link move up and down by moving the first transverse partition and the second transverse partition up and down.

[0043] Specifically, the control accessory also includes a gas storage tank; a one-way valve is provided on the first branch pipe, and the gas storage tank is connected to the first branch pipe through the second branch pipe; the connection between the first branch pipe and the second gas supply pipe is located on the pipeline between the filter pressure reducing valve and the double-acting valve positioner.

[0044] Because of the presence of a one-way valve at the inlet of the gas storage tank, the external gas source flows into the third gas input end through the first branch pipe, but cannot flow in the reverse direction; and the length of time the angle valve closes depends on the size of the gas storage tank, without considering leakage in the gas pipeline, joints, and actuator chamber.

[0045] Specifically, both the third and fourth gas supply pipes of the double-acting valve positioner are equipped with switches.

[0046] Specifically, to make it more convenient to use and to increase the automation level of the multi-functional control mechanism of the hydrogenation reaction system described in this invention, the multi-functional control mechanism of the hydrogenation reaction system also includes a DCS control system. The signal output terminal of the DCS control system is respectively connected to the switch on the third gas pipeline and the switch on the fourth gas pipeline. The DCS control system can control the opening and closing of the switch on the third gas pipeline and the switch on the fourth gas pipeline.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] 1. The multi-functional control mechanism of the hydrogenation reaction system described in this invention meets the safe production control of the hydrogenation reaction system, and can take into account the interlocking action in emergency situations and the occurrence of unexpected situations (sudden loss of power supply, control of gas supply and control of excessively low gas pressure), and can well ensure the safe and stable operation of the system.

[0049] 2. Due to the large pressure difference between the pressure flowing out of the hydrogenation reaction system and the post-treatment system, conventional diaphragm actuators cannot provide such a large thrust, making it impossible to promptly cut off the material flowing out of the hydrogenation reaction system. However, the multi-functional control mechanism described in this invention can achieve emergency shut-off control of the angle valve by cutting off the gas source signal when interlocked (solenoid valve de-energized). In the event of gas or power failure, the actuator closes the angle valve, thereby preventing the material from suddenly flowing into the post-treatment system due to high pressure, which could cause irreversible damage to the post-treatment system.

[0050] 3. The multifunctional control mechanism of the hydrogenation reaction system described in this invention is superior to conventional control devices in ensuring safe production.

[0051] 4. Hydrogenation reaction is a key hazardous chemical process under supervision. The multi-functional control mechanism of the hydrogenation reaction system can well meet the production and operation needs of hydrogenation reaction, and can also meet the control needs of other reactors, and has a high prospect for promotion and application.

[0052] 5. The multifunctional control mechanism of the hydrogenation reaction system described in this invention can achieve long-term stable operation of the hydrogenation reaction system, ensure safe production, reduce consumption, and can be further used in subsequent expansion of KA oil units with good results.

[0053] 6. The multifunctional control mechanism of the hydrogenation reaction system described in this invention has significant advantages over other types in terms of design, economy, safety and environmental protection. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the hydrogenation reaction system described in Example 1;

[0055] Figure 2 This is a schematic diagram of the multifunctional control mechanism of the hydrogenation reaction system described in Example 2;

[0056] Figure 3 This is an operation diagram showing the addition of catalyst according to temperature and pressure conditions during the operation of the hydrogenation reaction system described in Example 1;

[0057] Figure 4 It is a curve showing the temperature and pressure of the hydrogenation reaction system described in Example 1 during one day of operation. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0060] Example 1

[0061] like Figure 1 As shown, a hydrogenation reaction system includes a hydrogenation settling tank 41, a benzene storage tank 31, a high-purity water storage tank 32, a hydrogen storage tank 33, and two hydrogenation reactors (specifically, a first hydrogenation reactor 21 and a second hydrogenation reactor 24).

[0062] The first hydrogenation reactor 21 is provided with a first overflow weir 22, and the second hydrogenation reactor 24 is provided with a second overflow weir 25. The first overflow weir 22 includes a first horizontal part, a first vertical part, and a second horizontal part. The top end of the first vertical part is connected to the right end of the first horizontal part, the bottom end of the first vertical part is connected to the left end of the second horizontal part, and the right end of the second horizontal part is connected to the right side wall of the first hydrogenation reactor 21. That is, the height of the second horizontal part in the horizontal direction is lower than that of the first horizontal part.

[0063] The second overflow weir 25 includes a third horizontal section, a second vertical section, and a fourth horizontal section. The top end of the second vertical section is connected to the right end of the third horizontal section, the bottom end of the second vertical section is connected to the left end of the fourth horizontal section, and the right end of the fourth horizontal section is connected to the right side wall of the second hydrogenation reactor 24; that is, the fourth horizontal section is lower than the third horizontal section in the horizontal direction.

[0064] The benzene storage tank 31 is connected to the first hydrogenation reactor 21 through the first feed pipe 34, the high-purity water storage tank 32 is connected to the first feed pipe 34 through a pipeline, and the hydrogen storage tank 33 is connected to the first hydrogenation reactor 21 through the first gas inlet pipe 35; the connection end of the first feed pipe 34 to the first hydrogenation reactor 21 and the connection end of the first gas inlet pipe 35 to the first hydrogenation reactor 21 are both lower than the first overflow weir 22.

[0065] The first hydrogenation reactor 21 is connected to the second hydrogenation reactor 24 via the first discharge pipe 23, and the hydrogen storage tank 33 is connected to the second hydrogenation reactor 24 via the second inlet pipe 36; the connection end of the first discharge pipe 23 to the first hydrogenation reactor 21 is higher than the first overflow weir 22, and the connection end of the first discharge pipe 23 to the second hydrogenation reactor 24 is lower than the second overflow weir 25; the connection end of the second inlet pipe 36 to the second hydrogenation reactor 24 is lower than the second overflow weir 25; more preferably, the connection end of the first discharge pipe 23 to the first hydrogenation reactor 21 is lower than the first horizontal section and higher than the second horizontal section;

[0066] The second hydrogenation reactor 24 is connected to the top inlet of the hydrogenation settling tank 41 via the second discharge pipe 26. The bottom of the hydrogenation settling tank 41 is provided with a third discharge pipe 42. The first hydrogenation reactor 21 is connected to the third discharge pipe 42 via a return pipe 43. The connection end of the return pipe 43 and the first hydrogenation reactor 21 is lower than the first overflow weir 22. More preferably, the connection end of the second discharge pipe 26 and the second hydrogenation reactor 24 is lower than the third horizontal section and higher than the fourth horizontal section.

[0067] Specifically, the first feed pipe 34 is equipped with a first control valve 341 and a first feed pump 342 to control the entry of benzene and high-purity water into the first hydrogenation reactor 21. The first gas inlet pipe 35 is equipped with a second control valve 351 and a first gas inlet pump 352; the second gas inlet pipe 36 is equipped with a second control valve 361 and a second gas inlet pump 362, to control the amount of hydrogen entering the first hydrogenation reactor 21 and the second hydrogenation reactor 24, respectively. The return pipe 43 is equipped with a fourth control valve 45 and a catalyst slurry circulation pump 44 to control the entry of catalyst slurry into the first hydrogenation reactor 21.

[0068] The return pipe 43 is also equipped with a post-treatment discharge pipe 46. The reaction products are separated by settling in the hydrotreating settling tank 41. The catalyst slurry with a higher specific gravity is sent from the hydrotreating settling tank 41 to the bottom of the first hydrotreating reactor 21 by the catalyst slurry circulation pump 44. The oil phase with a lower specific gravity is separated by pressure difference and sent to the post-treatment system through the post-treatment discharge pipe 46. The post-treatment system includes devices such as a hydrotreating flash tank.

[0069] Specifically, before the reaction, a ruthenium-zinc catalyst is added to the hydrogenation settling tank 41. During the operation of the hydrogenation reactor, benzene supplied from the benzene storage tank 31 and hydrogen supplied from the hydrogen storage tank 33 are used as raw materials. In the presence of the ruthenium-zinc catalyst, cyclohexanol is partially hydrogenated to produce cyclohexene and cyclohexane as a byproduct.

[0070] In order to suppress the leaching of harmful metal components that could poison the catalyst, the present invention optimizes the materials of each device in the hydrogenation reaction system, and selects Hastelloy or NAR25-50MTi as the material for each device.

[0071] Further preferably, the first hydrogenation reactor 21 and the second hydrogenation reactor 24 are also equipped with a gas distributor and a liquid distributor (not shown in the figure). The outlet end of the first feed pipe 34 is connected to the liquid distributor in the first hydrogenation reactor 21, and the outlet end of the first gas inlet pipe 35 is connected to the gas distributor in the first hydrogenation reactor 21; the outlet end of the first discharge pipe 23 is connected to the liquid distributor in the second hydrogenation reactor 24, and the outlet end of the second gas inlet pipe 36 is connected to the gas distributor in the second hydrogenation reactor 24. By setting gas distributors and liquid distributors in the first hydrogenation reactor 21 and the second hydrogenation reactor 24, the dispersion of materials and hydrogen can be better realized, the contact degree between materials and hydrogen can be improved, and a full reaction can be achieved.

[0072] The gas distributor and liquid distributor mentioned above can be made using existing equipment, and their structure is not the point of invention of this invention, so they will not be described in detail.

[0073] To facilitate the mixing of reactants, both the first hydrogenation reactor 21 and the second hydrogenation reactor 24 are equipped with stirrers. The benzene, hydrogen and catalyst slurry are mixed evenly by the stirrers to carry out the reaction.

[0074] Furthermore, the first hydrogenation reactor 21 and the second hydrogenation reactor 24 are also equipped with heat removal devices. These devices can control the reaction temperature at a certain level, thereby adjusting the catalyst activity and maintaining the reaction pressure at a certain level. Specifically, the heat removal device is a heat-conducting coil installed within the first hydrogenation reactor 21 and the second hydrogenation reactor 24. The heat-conducting coil can dissipate the reaction heat from the first hydrogenation reactor 21 and the second hydrogenation reactor 24, thereby achieving temperature control.

[0075] In a further preferred embodiment, the heat-conducting coils in the first hydrogenation reactor 21 and / or the second hydrogenation reactor 24 can be connected in series with the high-purity water storage tank 32. By adjusting the flow rate of high-purity water flowing from the high-purity water storage tank 32 into the heat-conducting coils, the heat of reaction can be recovered, thereby regulating the reaction temperature and reducing heat consumption. Alternatively, the high-purity water in the high-purity water storage tank 32 can be heated using external equipment.

[0076] Furthermore, during the operation of the hydrogenation reaction system, the catalyst slurry in the hydrogenation settling tank 41 can be discharged and sent to the hydrogenation catalyst regeneration system. The regenerated catalyst can then be returned to the first hydrogenation reactor 21 for reuse.

[0077] The reaction product enters the hydrotreating settling tank 41. In the hydrotreating settling tank 41, it is necessary to achieve good separation of the slurry and the oil phase and control the oil-water interface to prevent the catalyst slurry from flowing out and causing corrosion of the dehydration system and loss of high-priced catalyst during post-processing.

[0078] The stirrer, heat removal device, and hydrogenation catalyst regeneration system can all be conventional equipment in the prior art, and their structure is not the inventive point of this invention, so they will not be described in detail.

[0079] Furthermore, a first DCS control system can be added as a variable frequency flow regulating device to control the circulation rate of the catalyst slurry returning to the first hydrogenation reactor 21. The first DCS control system can be connected to the fourth control valve 45 and the catalyst slurry circulation pump 44, and the return flow rate can be changed by changing the size of the fourth control valve 45. Specifically, in this invention, the connection relationship between the first DCS control system and the fourth control valve 45 and the catalyst slurry circulation pump 44 can be achieved using existing technology and is not the inventive point of this invention, so it will not be described in detail.

[0080] The specific operating principle of the hydrogenation reaction system is as follows:

[0081] 1) Pretreated benzene flows out from benzene storage tank 31, while high-purity water used to adjust the catalyst slurry flows out from high-purity water storage tank 32 and mixes with benzene. After being pressurized by the first feed pump 342 on the first feed pipe 34, it enters the liquid distributor at the bottom of the first hydrogenation reactor 21.

[0082] Hydrogen gas is fed from the hydrogen storage tank 33 into the gas distributor at the bottom of the first hydrogenation reactor 21 through the first inlet pipe 35, and simultaneously fed from the hydrogen storage tank 33 into the gas distributor at the bottom of the second hydrogenation reactor 24 through the second inlet pipe 36.

[0083] The catalyst slurry is fed from the hydrogenation settling tank 41 to the bottom of the first hydrogenation reactor 21 through the catalyst slurry circulation pump 44 on the return pipe 43.

[0084] 2) Then, the reactants react in the first hydrogenation reactor 21. The mixture formed by the unreacted reactants and the catalyst slurry flows from bottom to top in the first hydrogenation reactor 21, over the first overflow weir 22, and then flows into the top of the second horizontal section of the first overflow weir 22 by the difference in elevation between the second horizontal section and the first horizontal section. Then it enters the liquid distributor at the bottom of the second hydrogenation reactor 24 through the first discharge pipe 23.

[0085] Meanwhile, hydrogen is introduced into the second hydrogenation reactor 24 through the second inlet pipe 36. Unreacted materials react with hydrogen, and the reaction product flows over the second overflow weir 25 and into the top of the fourth horizontal section of the second overflow weir 25 by the position difference between the third and fourth horizontal sections. It then flows into the hydrogenation settling tank 41 through the second outlet pipe 26. The product is separated by settling in the hydrogenation settling tank 41. The catalyst slurry with a higher specific gravity is sent from the hydrogenation settling tank 41 to the bottom of the first hydrogenation reactor 21 by the catalyst slurry circulation pump 44, while the oil phase with a lower specific gravity is separated by pressure difference and sent to the post-treatment system.

[0086] Example 2

[0087] To facilitate the control of different material discharge conditions from the hydrogenation reaction system, and to avoid situations where the pressure difference between the material flowing out of the hydrogenation reaction system and the post-processing system is too large, or where the system is shut down in an emergency due to an interlock power failure, resulting in uncontrollable material discharge and impacting the post-processing system, thereby improving system safety and ensuring the safe conduct of the hydrogenation reaction.

[0088] Example 2 provides a multifunctional control mechanism for the hydrogenation reaction system described in Example 1, such as... Figure 1 , 2 As shown, it includes an angle valve 1, a double-acting valve positioner 2, an actuator, and control accessories; the control accessories include a first pneumatic directional valve 8, a second pneumatic directional valve 9, and a gas storage tank 4.

[0089] like Figure 1 As shown, angle valve 1 is installed on the aftertreatment discharge pipe 46. Figure 1 Only the position of angle valve 1 in the hydrogenation reaction system is shown in the figure. For the connection relationships of other components in the multi-functional control mechanism of the hydrogenation reaction system, please refer to [the diagram / reference needed]. Figure 2 .

[0090] The first pneumatic directional valve 8 is provided with a first gas input end, a second gas input end, and a first gas output end, wherein the first gas input end is located on the right side of the first pneumatic directional valve 8, the second gas input end is located on the lower side of the first pneumatic directional valve 8, and the first gas output end is located on the left side of the first pneumatic directional valve 8; in this embodiment, the second input end is closed; the second pneumatic directional valve 9 is provided with a third gas input end, a fourth gas input end, and a second gas output end, wherein the third gas input end is located on the right side of the second pneumatic directional valve 9, the fourth gas input end is located on the lower side of the second pneumatic directional valve 9, and the second gas output end is located on the left side of the second pneumatic directional valve 9;

[0091] Both the first pneumatic directional valve 8 and the second pneumatic directional valve 9 are equipped with a directional switch, and the directional switch is equipped with a pneumatic input end; the directional switch on the first pneumatic directional valve 8 can switch the connection between the first gas input end and the first gas output end, or the connection between the second gas input end and the first gas output end; the directional switch on the second pneumatic directional valve 9 can switch the connection between the third gas input end and the second gas output end, or the connection between the fourth gas input end and the second gas output end.

[0092] An external air source is connected to the pneumatic input terminal of the commutator on the first pneumatic directional valve 8 and the second pneumatic directional valve 9 through the first air supply pipe 13. A solenoid valve 11 and a position holding valve 10 are sequentially provided on the first air supply pipe 13.

[0093] The double-acting valve positioner 2 can realize the access and exit of the air path. The external air source is connected to the first air inlet of the double-acting valve positioner 2 through the second air supply pipe 14. The second air supply pipe 14 is equipped with a filter pressure reducing valve 3.

[0094] The double-acting valve positioner 2 is provided with two gas output pipes, namely the third gas supply pipe 16 and the fourth gas supply pipe 17. The third gas supply pipe 16 is connected to the first gas input end, and the fourth gas supply pipe 17 is connected to the fourth gas input end. The third gas supply pipe 16 is provided with a first pneumatic power amplifier 6, and the fourth gas supply pipe 17 is provided with a second pneumatic power amplifier 7.

[0095] The second gas supply pipe 14 is also provided with a first branch pipe 15, which is connected to the third gas input end; the first branch pipe 15 is provided with a one-way valve 5, and the gas storage tank 4 is connected to the first branch pipe 15 through the second branch pipe; the connection between the first branch pipe 15 and the second gas supply pipe 14 is located on the pipeline between the filter pressure reducing valve 3 and the double-acting valve positioner 2.

[0096] Because of the presence of a one-way valve 5 at the inlet of the gas storage tank 4, the external gas source flows into the third gas input end through the first branch pipe 15, and cannot flow in the reverse direction; and the length of time the angle valve 1 closes depends on the size of the gas storage tank 4 (generally determined according to the safety time of the process) without considering leakage in the gas pipeline, joints, and actuator gas chamber.

[0097] The actuator includes an upper air chamber 18 and a lower air chamber 19. The lower air chamber 19 is attached to the bottom end of the upper air chamber 18. The upper air chamber 18 is provided with a first transverse partition 181, which divides the upper air chamber 18 into a first upper chamber and a first lower chamber. The lower air chamber 19 is provided with a second transverse partition 191, which divides the lower air chamber 19 into a second upper chamber and a second lower chamber.

[0098] The first transverse partition 181 is provided with a first sliding member at both the left and right ends. The left end of the first transverse partition 181 is connected to the left side wall of the actuator through the first sliding member, and the right end of the first transverse partition 181 is connected to the right side wall of the actuator through the first sliding member. The first transverse partition 181 can slide up and down in the upper air chamber 18 through the first sliding member.

[0099] The second diaphragm 191 is provided with a second sliding member at both the left and right ends. The left end of the second diaphragm 191 is connected to the left side wall of the actuator through the second sliding member, and the right end of the second diaphragm 191 is connected to the right side wall of the actuator through the second sliding member. The second diaphragm 191 can slide up and down in the lower air chamber 19 through the second sliding member.

[0100] The first gas output terminal has two branches, one of which is connected to the first lower chamber and the other of which is connected to the second lower chamber. The second gas output terminal has two branches, one of which is connected to the first upper chamber and the other of which is connected to the second upper chamber.

[0101] The actuator also includes a first link, a second link, and a transmission rod 20 disposed outside the actuator. The first link, the second link, and the transmission rod 20 are located on the front side of the actuator, and both the first link and the second link extend in the front-rear direction. The rear end of the first link is connected to the first transverse partition 181, and the front end of the first link is connected to the upper part of the transmission rod 20. The rear end of the second link is connected to the second transverse partition 191, and the front end of the first link is connected to the upper part of the transmission rod 20. The up-and-down movement of the first transverse partition 181 and the second transverse partition 191 can drive the transmission rod 20, the first link, and the second link to move up and down.

[0102] Angle valve 1 includes a valve core chamber, an inlet end, and an outlet end, such as... Figure 1 , Figure 2As shown in the dashed box, the right side of the dashed box is the input end, the bottom side is the output end, and the left side is the valve core chamber. The valve core chamber contains a valve core, which divides the valve core chamber into upper and lower chambers. The valve core in the valve core chamber can control the opening degree of the connection between the input end and the output end of the angle valve 1, thereby realizing the opening and closing of the angle valve 1. The bottom end of the transmission rod 20 is connected to the valve core, and the transmission rod 20 can drive the valve core to move up and down relative to the valve core chamber.

[0103] The models of the components involved in Embodiments 1 and 2 above are as follows:

[0104] The first pneumatic directional valve 8 is model 250A-11-17W, the second pneumatic directional valve 9 is model 250A-16W, the solenoid valve 11 is model JE48320A101MB, the position holding valve 10 is model CL420, the actuator is model SLOP1000X, the first pneumatic power amplifier 6 is model IL100-NO2, the second pneumatic power amplifier 7 is model IL100-NO2, the check valve 5 is model C250-4W, the double-acting valve positioner 2 is model HEP-28, the filter pressure reducing valve 3 is model KZ03-3BX, and the gas storage tank 4 is model VT200L.

[0105] Furthermore, both the third air supply pipe 16 and the fourth air supply pipe 17 of the double-acting valve positioner 2 are equipped with switches.

[0106] To enhance ease of use and increase the automation level of the multifunctional control mechanism of the hydrogenation reaction system described in this invention, the multifunctional control mechanism further includes a second DCS control system. The signal output terminals of the second DCS control system are respectively connected to the switches on the third gas pipeline 16 and the fourth gas pipeline 17. The second DCS control system can control the opening and closing of the switches on the third gas pipeline 16 and the fourth gas pipeline 17. Specifically, in this invention, the connection relationship between the second DCS control system and the switches on the third gas pipeline 16 and the fourth gas pipeline 17 can be achieved using existing technology and is not the inventive point of this invention, so it will not be elaborated further.

[0107] The function of angle valve 1 is to control the discharge of materials in the hydrogenation reaction system. Angle valve 1 is used in situations where there is a large pressure difference before and after the pipeline. Since the pressure difference before and after angle valve 1 is relatively large, the actuator can also be a piston-type high-thrust actuator.

[0108] The air supply interface of the double-acting valve positioner 2 is 1 / 4 NPT. The function of the double-acting valve positioner 2 is to operate in a double-acting manner by opening or closing the third air supply pipe 16 and the fourth air supply pipe 17, thereby accurately and quickly positioning the valve core in the angle valve 1.

[0109] The air supply interfaces for both the upper air chamber 18 and the lower air chamber 19 of the actuator are 1 / 4 NPT. In actual production, the air line fittings should be checked regularly to avoid the actuator from malfunctioning due to air leaks.

[0110] The set pressure of the filter pressure reducing valve 3 should be 400 kPa, and the pressure setting should be based on meeting the actuator's air supply pressure.

[0111] The filter pressure reducing valve 3 is equipped with an adjusting spring and a diaphragm. Its function is to set the outlet pressure by adjusting the spring pressure and control the outlet pressure change using the diaphragm. By adjusting the gas flow area on the second gas supply pipe 14, it achieves pressure reduction and stabilization. Additionally, the filter pressure reducing valve 3 has a filter chamber that can filter the components of external gas sources. When external gas passes through the filter pressure reducing valve 3, it can purify the external gas source.

[0112] In actual production, the filter pressure reducing valve 3 should be checked and cleaned regularly, and compressed air should be released during shutdown to prevent water accumulation or leakage of the desiccant used in the compressed air from clogging the filter pressure reducing valve 3.

[0113] The gas storage tank 4 has two 1 / 4 NPT gas source interfaces, and its volume is 200 liters. The function of the gas storage tank 4 is to store gas, which solves the contradiction that the gas consumption may exceed the gas supply in the multi-functional control mechanism of the hydrogenation reaction system in a short period of time, and can also be used temporarily in case of sudden events such as insufficient external gas supply or gas interruption (or power outage).

[0114] The gas source interface of the one-way valve 5 is 1 / 4 NPT. The function of the one-way valve 5 is to allow the external gas source to flow into the third gas input terminal through the first branch pipe 15, and prevent backflow.

[0115] The air source interface of the first pneumatic power amplifier 6 and the second pneumatic power amplifier 7 is 1 / 4 NPT. Especially in situations where the air pipeline is long and the actuator capacity is large, it is necessary to configure a pneumatic amplifier.

[0116] The first pneumatic power amplifier 6 and the second pneumatic power amplifier 7 amplify the airflow through the third air supply pipe 16 and the fourth air supply pipe 17, respectively, to increase the movement speed of the valve core in the angle valve 1. Both the first pneumatic power amplifier 6 and the second pneumatic power amplifier 7 are equipped with pressure-sensitive diaphragms and pneumatic valve cores. When an external air source inputs pressure to the input port of the first pneumatic power amplifier 6 or the second pneumatic power amplifier 7, the diaphragm on the amplifier is subjected to pressure, causing displacement of the diaphragm assembly and the pneumatic valve core. The amplification of the airflow is achieved through changes in the mechanisms (diaphragm assembly, pneumatic valve core, etc.) within the first pneumatic power amplifier 6 or the second pneumatic power amplifier 7.

[0117] The air source interface of the first pneumatic reversing valve 8 and the second pneumatic reversing valve 9 is 1 / 4 NPT, and a 1 / 8*1 / 4 NPT connector is required at the joint.

[0118] The first pneumatic reversing valve 8 and the second pneumatic reversing valve 9 use gas pressure to act on the reversing device, thereby changing the flow direction of the gas. The first pneumatic reversing valve 8 and the second pneumatic reversing valve 9 are set with threshold values. When the gas pressure reaches a certain level or falls below a certain level, the reversing device can switch the connection relationship between the gas input end and the gas output end.

[0119] All air supply interfaces of the position holding valve 10 are 1 / 4 NPT. In actual production, the set pressure of the position holding valve 10 is adjustable. The pressure setting must be carefully considered to meet the actuator's required pressure while also taking into account the pressure and possible fluctuation range of the external air source (compressed air). Specifically, the set pressure of the position holding valve 10 should be 400 kPa (not exceeding the actuator's rated pressure).

[0120] The function of the position-holding valve 10 is to determine the level of the external air source pressure based on the set pressure. When the pressure is lower than the set value, the output side of the position-holding valve 10 is vented. By setting the position-holding valve 10, when the external air source pressure entering the first pneumatic reversing valve 8 and the second pneumatic reversing valve 9 is 0 MPaG, both the first pneumatic reversing valve 8 and the second pneumatic reversing valve 9 are reversed. The fourth gas input terminal of the second pneumatic reversing valve 9 is connected to the second gas output terminal. The compressed air in the gas storage tank 4 enters the first upper chamber and the second upper chamber of the actuator. The first gas input terminal and the first gas output terminal of the first pneumatic reversing valve 8 are connected.

[0121] All solenoid valves 11 have a 1 / 4 NPT gas supply interface, and are energized type. The function of solenoid valve 11 is to cut off the gas supply in an emergency by controlling its energization or de-energization.

[0122] The gas pipelines in the multi-functional control mechanism of the hydrogenation reaction system, including the first gas pipeline 13, the second gas pipeline 14, the first branch pipeline 15, the third gas pipeline 16, and the fourth gas pipeline 17, are as follows: Stainless steel pipes improve corrosion resistance.

[0123] In actual production, the explosion-proof rating of solenoid valve 11 and double-acting valve positioner 2 should meet the requirements of explosion-proof zone division in the production site.

[0124] In actual production, the time from when angle valve 1 is fully closed to when it is fully open is determined according to the operating process and the specifications of angle valve 1. If this time is too long, it will not meet the requirements for safe and stable operation of the production system. It is necessary to check and test each component in the multi-functional control mechanism of the hydrogenation reaction system. Generally, the sealing performance of angle valve 1 and actuator should be checked first to prevent cross-contamination between upper gas chamber 18 and lower gas chamber 19, which would affect the opening and closing speed of the actuator.

[0125] In actual production, during the shutdown of the multi-functional control mechanism of the hydrogenation reaction system, functional tests are required. These tests include checking and confirming the leakage of angle valve 1, the airtightness of the actuator, the stroke of angle valve 1, the hysteresis of angle valve 1, the performance of check valve 5, the performance of the first pneumatic power amplifier 6 and the second pneumatic power amplifier 7, the performance of the first pneumatic directional valve 8 and the second pneumatic directional valve 9, the performance of solenoid valve 11, and the pipe fittings. This process is called single-machine debugging. Then, system-wide debugging is performed, with tests conducted under normal production conditions, interlock conditions (solenoid valve de-energized state), loss of air supply, and compressed air pressure fluctuations (below the set pressure of the position holding valve by 400 kPa) to ensure that all functions of the multi-functional control mechanism of the hydrogenation reaction system are normal.

[0126] In the interlocked state (i.e., the solenoid valve 11 is de-energized), the angle valve 1 at the outlet of the hydrogenation settling tank 41 is closed urgently (achieved through the multi-functional control mechanism of the hydrogenation reaction system). The purpose is to prevent the material in the hydrogenation settling tank 41 from flowing into the post-processing system (specifically, for example, the hydrogenation flash tank), causing the hydrogenation settling tank 41 to be emptied and resulting in cross-pressure between the hydrogenation reaction system and the hydrogenation flash tank in the post-processing system. Since the pressure in the first hydrogenation reactor 21 and / or the second hydrogenation reactor 24 is high, while the pressure in the hydrogenation flash tank is low, cross-pressure could lead to serious dangers such as damage to equipment in the post-processing system, including the hydrogenation flash tank. Therefore, when the system is shut down, the angle valve 1 needs to be completely closed urgently to disconnect the connection between the hydrogenation reaction system and the post-processing system.

[0127] The specific operating principle of the multi-functional control mechanism of the hydrogenation reaction system is as follows:

[0128] First, open the filter pressure reducing valve 3, solenoid valve 11, and position holding valve 10. The external air source (compressed air) is input through the first air supply pipe 13 to the pneumatic input terminals of the directional switches on the first pneumatic reversing valve 8 and the second pneumatic reversing valve 9, respectively. The first pneumatic reversing valve 8 and the second pneumatic reversing valve 9 operate in three ways:

[0129] (1) Under normal circumstances, the switches of the third gas supply pipe 16 and the fourth gas supply pipe 17 on the double-acting valve positioner 2 are turned on (this process can also be achieved by the second DCS control system outputting a 4-20mA DC signal to the switches of the third gas supply pipe 16 and the fourth gas supply pipe 17). The external gas source is input to the double-acting valve positioner 2 through the second gas supply pipe 14. The double-acting valve positioner 2 outputs two gas paths. One path is output to the first pneumatic power amplifier 6, which is amplified and then sent to the first gas input end. The other path is output to the second pneumatic power amplifier 7, which is amplified and then sent to the fourth gas input end.

[0130] At this time, since the solenoid valve 11 is energized and open, the external air source acts on the pneumatic input end of the directional switch on the first pneumatic directional valve 8 and the second pneumatic directional valve 9 via the position holding valve 10; through the switching of the directional switch on the second pneumatic directional valve 9, the fourth gas input end is connected to the second gas output end, and at the same time the first gas input end and the first gas output end are connected; after the amplification effect of the first pneumatic power amplifier 6 and the second pneumatic power amplifier 7, the external air source is sent to the first upper chamber, the first lower chamber, the second upper chamber and the second lower chamber of the actuator respectively, and then by changing the side air pressure on the upper and lower sides of the first transverse partition 181 and the second transverse partition 181, the external air source is sent to the first upper chamber, the first lower chamber, the second upper chamber and the second lower chamber of the actuator. The air pressure on the upper and lower sides of the partition 191 causes the first horizontal partition 181 to move up and down relative to the upper air chamber 18, and the second horizontal partition 191 to move up and down relative to the lower air chamber 19, thereby driving the transmission rod 20 to move up and down. The transmission rod 20 then drives the valve core to move up and down relative to the valve core chamber, thereby controlling the opening of the angle valve 1. The opening of the angle valve 1 is determined by the air pressure difference to the first upper chamber, the first lower chamber, the second upper chamber, and the second lower chamber. When the air pressure to the first upper chamber and the first lower chamber are equal, and the air pressure to the second upper chamber and the second lower chamber are equal, the valve core of the angle valve 1 is in the middle position of the valve core chamber stroke.

[0131] When the pressure leading to the first upper chamber is greater than the pressure leading to the first lower chamber, and the pressure leading to the second upper chamber is greater than the pressure leading to the second lower chamber, the valve core of angle valve 1 is in the 0-50% position of the valve core chamber stroke. When the pressure leading to the first upper chamber is less than the pressure leading to the first lower chamber, and the pressure leading to the second upper chamber is less than the pressure leading to the second lower chamber, the valve core of angle valve 1 is in the 50-100% position of the valve core chamber stroke. When the pressure leading to the first and second upper chambers approaches zero, the valve core of angle valve 1 is in the 100% position of the valve core chamber stroke. When the pressure leading to the first and second lower chambers approaches zero, the valve core of angle valve 1 is in the 0% position of the valve core chamber stroke. By changing the position of the valve core in the valve core chamber, the opening degree of the connection between the input and output ends of angle valve 1 is realized, thereby realizing the opening and closing of angle valve 1. When the valve core in angle valve 1 is in the 0% or 100% position of the valve core chamber stroke, angle valve 1 is closed.

[0132] To ensure sufficient air volume delivered to the first and second upper chambers of the actuator via the second pneumatic reversing valve 9, the external air source (compressed air) enters the third gas input terminal after passing through the gas storage tank 4 via the first branch pipe 15. Since the first branch pipe 15 is equipped with a check valve 5, the external air source (compressed air) will not flow back through the first branch pipe 15. Excess external air source (compressed air) entering from the first branch pipe 15 is stored in the gas storage tank 4.

[0133] (2) In the interlocking state (i.e., the solenoid valve 11 is de-energized), the solenoid valve 11 cuts off the external air source of the first air supply pipe 13. At this time, the pressure of the position holding valve 10 decreases, which causes the air pressure acting on the directional switch of the second pneumatic directional valve 9 and the air pressure acting on the directional switch of the first pneumatic directional valve 8 to decrease. The directional switch of the second pneumatic directional valve 9 switches, and the third gas input end is connected to the second gas output end. The compressed air stored in the gas storage tank 4 enters the first upper chamber and the second upper chamber of the actuator. At the same time, the directional switch of the first pneumatic directional valve 8 switches, and the second input end is connected to the first gas output end. Since the second input end is in a closed state, the air pressure of the first upper chamber and the second upper chamber can be maintained. The air pressure of the first lower chamber and the second lower chamber decreases. When the pressure leading to the first lower chamber and the second lower chamber approaches zero, the valve core of the angle valve 1 is at the 0% position of the valve core chamber stroke, and the angle valve 1 is closed.

[0134] (3) When the first air supply pipe 13 is in the case of air loss, the pressure of the position holding valve 10 decreases, which causes the air pressure acting on the directional valve 9 and the air pressure acting on the directional valve 8 to decrease. At this time, the first pneumatic directional valve 8, the second pneumatic directional valve 9, the double-acting valve positioner 2, the actuator, and the angle valve 1 operate in the same manner as described above under the interlocking conditions.

[0135] In the hydrogenation reaction system described in Example 1, during operation, benzene and hydrogen react partially to produce cyclohexene, achieving the target conversion rate. By adjusting process parameters such as the supply rates of benzene and hydrogen, as well as the material flow rates, the conversion rates of benzene and cyclohexene are stably maintained within the target range. Furthermore, the concentration of benzene sulfides entering the first hydrogenation reactor 21 and the second hydrogenation reactor 24 is ensured to be below a specified value, guaranteeing a cyclohexene production rate that matches the cyclohexanol production rate.

[0136] The standards and specifications for the addition of raw materials during the operation of the hydrogenation reaction system described in Example 1 are as follows:

[0137] 1. Because hydrogenation catalysts experience a decrease in activity due to aging during operation, it is necessary to frequently perform operations to maintain catalyst activity. The main steps are detailed below. Figure 3 , Figure 4 . Figure 4 The figure shows the temperature and pressure curves of the hydrogenation reaction system during one day of operation. Figure 4 In Chinese, M / U stands for supplementary operation and B / D stands for discharge operation.

[0138] 2. Method for setting production volume

[0139] The target values ​​for the amount of benzene and hydrogen to be added are set according to the following formula. In actual addition, fine-tuning is required to achieve a balance with the actual production of cyclohexanol.

[0140]

[0141]

[0142] In the above formulas, the benzene conversion rate and cyclohexene selectivity are determined based on catalyst activity evaluation. In actual production, a baseline benzene conversion rate and cyclohexene selectivity need to be designed. Once the cyclohexanol production rate is determined, the target flow rate for the hydrogenation reaction can be further set.

[0143] The precautions for operating the hydrogenation reaction system described in Example 1 are as follows:

[0144] 1. During operation, hydrogenation catalysts may experience a decrease in activity due to hydrogen adsorption and other factors. Therefore, multiple catalyst regeneration operations are required daily to maintain their activity.

[0145] 2. Figure 4In the diagram, the temperature and pressure changes in the A-B, B-D, and E-F intervals reflect the influence of the hydrogenation reaction system during catalyst regeneration. The temperature differences between A and B, C and D, and E and F are caused by catalyst regeneration, indicating the effectiveness of catalyst regeneration. The regeneration operation is a batch operation.

[0146] Figure 4 In this process, the activity maintenance between the first M / U and the next M / U is achieved by increasing the temperature setting. The principle is as follows: when hydrogen is left over due to decreased activity, the pressure will rise. When the pressure rises to exceed the management value, the temperature setting is increased to improve activity. The pressure is then adjusted to approach the management value, and the temperature setting index is increased at the same time.

[0147] 3. The portion of catalyst activity not recovered during regeneration will manifest itself through a one-day temperature rise, such as... Figure 4 The temperature difference between points E and A.

[0148] 4. When the temperature rises and the zinc concentration of the catalyst exceeds a certain threshold, dilute sulfuric acid needs to be added to maintain the reaction. When the zinc concentration of the catalyst falls below the threshold, new catalyst needs to be added to maintain activity.

[0149] The above embodiments are merely examples of several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention.

[0150] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydrogenation reaction system with a multifunctional control mechanism, characterized in that, It includes a hydrogenation settling tank, a benzene storage tank, a high-purity water storage tank, a hydrogen storage tank, as well as a first hydrogenation reactor and a second hydrogenation reactor; The first hydrogenation reactor is equipped with a first overflow weir, and the second hydrogenation reactor is equipped with a second overflow weir; The benzene storage tank is connected to the first hydrogenation reactor via the first feed pipe, the high-purity water storage tank is connected to the first feed pipe via a pipeline, and the hydrogen storage tank is connected to the first hydrogenation reactor via the first gas inlet pipe; the connection end of the first feed pipe to the first hydrogenation reactor and the connection end of the first gas inlet pipe to the first hydrogenation reactor are both lower than the first overflow weir. The first hydrogenation reactor is connected to the second hydrogenation reactor via the first discharge pipe, and the hydrogen storage tank is connected to the second hydrogenation reactor via the second inlet pipe; the connection end of the first discharge pipe to the first hydrogenation reactor is higher than the first overflow weir, and the connection end of the first discharge pipe to the second hydrogenation reactor is lower than the second overflow weir; the connection end of the second inlet pipe to the second hydrogenation reactor is lower than the second overflow weir. The second hydrogenation reactor is connected to the top inlet of the hydrogenation settling tank via the second discharge pipe. The bottom of the hydrogenation settling tank is provided with a third discharge pipe. The first hydrogenation reactor is connected to the third discharge pipe via a return pipe. The connection end of the return pipe to the first hydrogenation reactor is lower than the first overflow weir. The return pipe is equipped with a fourth control valve and a catalyst slurry circulation pump; the return pipe is also equipped with a post-treatment discharge pipe; The multi-functional control mechanism includes an angle valve, a double-acting valve positioner, an actuator, and control accessories; the control accessories include a first pneumatic directional valve, a second pneumatic directional valve, and a gas storage tank. The first pneumatic directional valve has a first gas input end, a second gas input end, and a first gas output end, with the second input end closed; the second pneumatic directional valve has a third gas input end, a fourth gas input end, and a second gas output end. Both the first pneumatic directional valve and the second pneumatic directional valve are equipped with a directional switch, and the directional switch is equipped with a pneumatic input end; the directional switch on the first pneumatic directional valve can switch the connection between the first gas input end and the first gas output end, or the connection between the second gas input end and the first gas output end; the directional switch on the second pneumatic directional valve can switch the connection between the third gas input end and the second gas output end, or the connection between the fourth gas input end and the second gas output end. An external air source is connected to the pneumatic input terminal of the commutator on the first pneumatic directional valve and the second pneumatic directional valve respectively through the first air supply pipe. A solenoid valve is provided on the first air supply pipe. The double-acting valve positioner can realize the access and exit of the air path. The external air source is connected to the first air inlet of the double-acting valve positioner through the second air supply pipe. The double-acting valve positioner is equipped with two gas output pipes, namely the third gas supply pipe and the fourth gas supply pipe. The third gas supply pipe is connected to the first gas input end, and the fourth gas supply pipe is connected to the fourth gas input end. The actuator includes an upper air chamber and a lower air chamber. The upper air chamber is provided with a first transverse partition, which divides the upper air chamber into a first upper chamber and a first lower chamber. The lower air chamber is provided with a second transverse partition, which divides the lower air chamber into a second upper chamber and a second lower chamber. The first diaphragm can slide up and down in the upper air chamber, and the second diaphragm can slide up and down in the lower air chamber; The first gas output terminal has two branches, one of which is connected to the first lower chamber and the other of which is connected to the second lower chamber. The second gas output terminal has two branches, one of which is connected to the first upper chamber and the other of which is connected to the second upper chamber. The actuator also includes a first link, a second link, and a transmission rod disposed outside the actuator; the first link connects the first transverse partition to the transmission rod, the second link connects the second transverse partition to the transmission rod, and the movement of the first and second transverse partitions up and down drives the transmission rod, the first link, and the second link to move up and down. Angle valve includes a valve core chamber, an input end, and an output end; the valve core chamber contains a valve core, which divides the valve core chamber into upper and lower chambers. The valve core can control the opening and closing of the input end and the output end of the angle valve; the bottom end of the transmission rod is connected to the valve core, and the transmission rod can drive the valve core to move up and down relative to the valve core chamber. Angle valve is installed on the post-treatment discharge pipe.

2. The hydrogenation reaction system according to claim 1, characterized in that, The first overflow weir includes a first horizontal section, a first vertical section, and a second horizontal section. The top end of the first vertical section is connected to the right end of the first horizontal section, the bottom end of the first vertical section is connected to the left end of the second horizontal section, and the right end of the second horizontal section is connected to the right side wall of the first hydrogenation reactor. The second overflow weir includes a third horizontal section, a second vertical section, and a fourth horizontal section. The top of the second vertical section is connected to the right end of the third horizontal section, the bottom of the second vertical section is connected to the left end of the fourth horizontal section, and the right end of the fourth horizontal section is connected to the right side wall of the second hydrogenation reactor.

3. The hydrogenation reaction system according to claim 1, characterized in that, The first feed pipe is equipped with a first control valve and a first feed pump; the first air inlet pipe is equipped with a second control valve and a first air inlet pump; the second air inlet pipe is equipped with a second control valve and a second air inlet pump.

4. The hydrogenation reaction system according to claim 1, characterized in that, The first gas input terminal is located on the right side of the first pneumatic reversing valve, the second gas input terminal is located below the first pneumatic reversing valve, and the first gas output terminal is located on the left side of the first pneumatic reversing valve. The third gas input terminal is located to the right of the second pneumatic directional valve, the fourth gas input terminal is located below the second pneumatic directional valve, and the second gas output terminal is located to the left of the second pneumatic directional valve.

5. The hydrogenation reaction system according to claim 1, characterized in that, The first gas supply pipe is equipped with a position-holding valve; the second gas supply pipe is equipped with a filter pressure-reducing valve; the third gas supply pipe is equipped with a first pneumatic power amplifier; and the fourth gas supply pipe is equipped with a second pneumatic power amplifier.

6. The hydrogenation reaction system according to claim 5, characterized in that, The second gas pipeline is also equipped with a first branch pipe, which is connected to the third gas input terminal.

7. The hydrogenation reaction system according to claim 6, characterized in that, The control accessories also include a gas storage tank; a one-way valve is provided on the first branch pipe, and the gas storage tank is connected to the first branch pipe through the second branch pipe; the connection between the first branch pipe and the second gas supply pipe is located on the pipeline between the filter pressure reducing valve and the double-acting valve positioner.

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