Energy-saving closed liquid ring vacuum system suitable for petrochemical device

Abstract

The invention discloses an energy-saving closed liquid ring vacuum system suitable for a petrochemical device, and belongs to the technical field of chemical production. Comprising a liquid ring vacuum pump which is connected with an external production system and is used for vacuumizing and extracting gas in the production system, hydrogenation solvent oil is adopted as a working solution in the liquid ring vacuum pump, the hydrogenation solvent oil has good thermal stability and can be kept stable in a high-temperature environment, and the requirement for frequently replacing the working solution is reduced; the gas-liquid separator is connected with the liquid ring vacuum pump, the top of the gas-liquid separator is connected with an exhaust pipeline, and the separated non-condensable gas is exhausted to a torch through the exhaust pipeline; the waste liquid collecting tank is connected with the gas-liquid separator through a liquid discharging pipeline, waste liquid discharged from the bottom of the gas-liquid separator is conveyed to an external recycling device through the waste liquid collecting tank, the environmental protection pressure caused by large water discharging amount is avoided, and the potential safety hazard problem existing when water containing organic solvents and toxic substances is discharged is also solved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production, and in particular relates to an energy-saving closed liquid ring vacuum system suitable for petrochemical equipment. Background Art

[0002] Traditional water ring vacuum pumps are widely used in chemical, pharmaceutical and other industries due to their working principle and structural characteristics. In normal applications, the working fluid of water ring vacuum pumps is mostly discharged directly, that is, the water discharged by the water ring vacuum pump enters a large circulating water pool or is directly discharged. This water supply and drainage method is easy to connect and simple to use, and is widely used in practical applications.

[0003] However, if the medium being pumped contains organic solvents, toxic substances, etc., the direct discharge of the working fluid has the following disadvantages:

[0004] 1. The working fluid temperature rises:

[0005] During the gas extraction process, the pumped gas mixes with the working fluid, especially when high-temperature non-condensable gas is sucked into the liquid ring vacuum pump, the working fluid temperature will increase significantly. In order to reduce the working temperature of the liquid ring vacuum pump, the working fluid must be replaced with fresh water regularly or irregularly, which not only increases the complexity and cost of operation, but also has a great impact on the working performance of the liquid ring vacuum pump.

[0006] 2. Environmental pollution and safety hazards:

[0007] The water discharged from the drain outlet will contain some organic solvents and toxic substances. Due to the large amount of water discharged, this puts a lot of pressure on the environmental protection. In addition, the water containing organic solvents and toxic substances will release harmful gases and some hydrocarbon substances, leading to an increase in the concentration of surrounding combustible gas and may trigger a large number of combustible gas alarms, posing a major safety hazard. Summary of the invention

[0008] The present invention aims at the above problems existing in the prior art and proposes an energy-saving closed liquid ring vacuum system suitable for petrochemical equipment, which can not only meet production needs but also achieve energy saving, consumption reduction and environmental protection.

[0009] The present invention can be achieved through the following technical solutions:

[0010] An energy-saving closed liquid ring vacuum system suitable for a petrochemical plant, comprising:

[0011] A liquid ring vacuum pump is connected to an external production system, and the gas in the production system is extracted by vacuuming the liquid ring vacuum pump, wherein hydrogenated solvent oil is used as a working fluid in the liquid ring vacuum pump;

[0012] A gas-liquid separator connected to the liquid ring vacuum pump, wherein the top of the gas-liquid separator is connected to an exhaust pipeline, through which the separated non-condensable gas is discharged to the flare;

[0013] A waste liquid collection tank is connected to the gas-liquid separator via a liquid discharge pipeline, and the waste liquid collection tank sends the waste liquid discharged from the bottom of the gas-liquid separator to an external refining device.

[0014] As a further improvement of the present invention, an inlet buffer tank is further provided on the pipeline between the external production system and the liquid ring vacuum pump.

[0015] As a further improvement of the present invention, the gas-liquid separator is also connected to a reflux pipeline, which is connected to the inlet buffer tank, and part of the gas discharged from the top of the gas-liquid separator is discharged to the inlet buffer tank through the reflux pipeline.

[0016] As a further improvement of the present invention, a demister is provided on the top of the gas-liquid separator, and the separated non-condensable gas is passed through the demister to remove liquid phase components.

[0017] As a further improvement of the present invention, the exhaust pipeline is further connected with a magnetic oxygen analyzer and a nitrogen purge line. When the magnetic oxygen analyzer detects that the oxygen content on the exhaust pipeline exceeds a preset value, nitrogen is released through the nitrogen purge line and the exhaust regulating valve on the exhaust pipeline is purged to dilute the oxygen concentration.

[0018] As a further improvement of the present invention, it also includes a liquid replenishing pipeline, which is connected to the gas-liquid separator and is used to replenish the working fluid.

[0019] As a further improvement of the present invention, it also includes a gas-liquid separator liquid level control system, which is composed of a liquid level meter and a liquid level transmitter. The liquid level meter is used to detect the liquid level in the gas-liquid separator in real time, wherein:

[0020] When the liquid level in the gas-liquid separator is higher than a preset value, the liquid level transmitter outputs a corresponding high liquid level current signal to the control system, and the control system opens the discharge regulating valve disposed on the discharge pipeline;

[0021] When the liquid level in the gas-liquid separator is lower than a preset value, the liquid level transmitter outputs a corresponding low liquid level current signal to the control system, and the control system opens the liquid replenishment switch valve disposed on the liquid replenishment pipeline.

[0022] As a further improvement of the present invention, a pump liquid supply pipeline is further provided between the bottom of the gas-liquid separator and the liquid inlet of the liquid ring vacuum pump, and a sealing flushing pump and a heat exchanger are provided on the pump liquid supply pipeline, wherein:

[0023] The liquid outlet of the liquid ring vacuum pump, the gas-liquid separator, the seal flushing pump, the heat exchanger, and the liquid inlet of the liquid ring vacuum pump are connected in sequence to form a circulation system.

[0024] As a further improvement of the present invention, it also includes a nitrogen pressure-compensating pipeline connected to the waste liquid collection tank. When the pressure in the waste liquid collection tank is lower than a preset value, the internal pressure is supplemented by nitrogen.

[0025] As a further improvement of the present invention, a pressure relief pipeline is further provided between the waste liquid collection tank and the inlet buffer tank. When the pressure in the waste liquid collection tank is higher than a preset value, the waste liquid collection tank releases pressure to the inlet buffer tank through the pressure relief pipeline.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. Use hydrogenated solvent oil as the working fluid, such as hydrogenated carbon nine +. This type of working fluid has good thermal stability and can remain stable in high temperature environments, ensuring the performance of the liquid ring vacuum pump and reducing the need for frequent replacement of the working fluid;

[0028] 2. The non-condensable gas separated by the gas-liquid separator is discharged to the flare through the exhaust pipeline for safe treatment, while the liquid containing organic solvents and toxic substances is sent to the waste liquid collection tank through the drainage pipeline, and then sent to the external refining device for refining through the waste liquid external pump to achieve resource recycling. This solves the environmental pressure caused by the large amount of water discharge on the one hand, and solves the safety hazards existing in the discharge of water containing organic solvents and toxic substances on the other hand;

[0029] 3. On the exhaust pipeline, the combination of the magnetic oxygen analyzer and the nitrogen purge system realizes an immediate response to changes in oxygen content, and can take prompt measures when the oxygen content exceeds the standard to ensure the safe operation of the system;

[0030] 4. The gas discharged from the top of the gas-liquid separator is separated twice by the demister to remove the liquid components, and then discharged to the flare or reflux pipeline through the exhaust pipeline. On the one hand, by efficiently removing the liquid components in the gas, the possibility of harmful substances being discharged with the gas is reduced, and the risk of environmental pollution is reduced. On the other hand, the captured liquid components can be returned to the bottom of the gas-liquid separator and enter the circulation system or sent to the waste liquid collection tank for refining, realizing the effective recycling of resources;

[0031] 5. The control system automatically opens the discharge regulating valve on the discharge pipeline according to the liquid level of the gas-liquid separator to realize the automatic discharge function, or automatically opens the replenishment switch valve on the replenishment pipeline to realize the automatic replenishment function. At the same time, it can also automatically control the start or stop of the waste liquid delivery pump to achieve the purpose of automatic discharge or automatic stop of discharge, thereby ensuring that the working fluid in the gas-liquid separator is always kept within an optimal liquid level range to avoid system performance degradation caused by excessively high or low liquid levels;

[0032] 6. The circulation system formed by the pump supply pipeline cools the working fluid of the liquid ring vacuum pump to maintain the best working state of the liquid ring vacuum pump and avoid performance degradation caused by working fluid temperature fluctuations or impurities. Through the efficient cooling and circulation system, unnecessary water consumption and other resource waste are reduced, and effective utilization of resources is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The invention is a schematic diagram of an energy-saving closed liquid ring vacuum system suitable for a petrochemical plant.

[0034] In the figure, 100, liquid ring vacuum pump; 110, pump liquid supply pipeline; 120, seal flushing pump; 130, heat exchanger; 140, material return pipeline;

[0035] 200, gas-liquid separator; 210, exhaust pipeline; 211, magnetic oxygen analyzer; 212, nitrogen purge pipeline; 220, drainage pipeline; 221, manual drainage pipeline; 222, automatic drainage pipeline; 230, reflux pipeline; 240, demister; 250, liquid replenishment pipeline;

[0036] 300. Waste liquid collection tank; 310. Waste liquid delivery pump; 320. Nitrogen pressure replenishing pipeline; 400. Inlet buffer tank. DETAILED DESCRIPTION

[0037] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical method of the present invention, but the present invention is not limited to these embodiments.

[0038] like Figure 1 As shown, the present invention provides an energy-saving closed liquid ring vacuum system suitable for petrochemical equipment, comprising:

[0039] A liquid ring vacuum pump 100 is connected to an external production system, and the gas in the production system is extracted by vacuuming the liquid ring vacuum pump 100. Hydrogenated solvent oil is used as a working fluid in the liquid ring vacuum pump 100;

[0040] A gas-liquid separator 200 is connected to the liquid ring vacuum pump 100. The top of the gas-liquid separator 200 is connected to an exhaust pipeline 210, and the separated non-condensable gas is discharged to the flare through the exhaust pipeline 210;

[0041] The waste liquid collection tank 300 is connected to the gas-liquid separator 200 via a liquid discharge pipeline 220 , and the waste liquid collection tank 300 sends the waste liquid discharged from the bottom of the gas-liquid separator 200 to an external recycling device.

[0042] It should be noted that in the prior art, the liquid ring vacuum pump 100 generally adopts a direct discharge method, and the discharged water enters a circulating water pool or is directly discharged. However, if the medium extracted from the production system contains high-temperature non-condensable gases, organic solvents, toxic substances, etc., this direct discharge method has the following disadvantages:

[0043] 1. High-temperature non-condensable gas will cause the working temperature in the liquid ring vacuum pump 100 to rise. Excessively high working temperature will have a great impact on the working performance of the liquid ring vacuum pump 100, resulting in the need to frequently replace fresh working fluid;

[0044] 2. Due to the large amount of water discharged, this puts a lot of pressure on the environmental protection. In addition, water containing organic solvents and toxic substances will release harmful gases and some hydrocarbon substances, leading to an increase in the concentration of surrounding combustible gas and may trigger a large number of combustible gas alarms, posing a major safety hazard.

[0045] To solve the above problems, in this embodiment, hydrogenated solvent oil is used as the working fluid, such as hydrogenated carbon nine +. This type of working fluid has good thermal stability and can remain stable in a high temperature environment, thereby ensuring the performance of the liquid ring vacuum pump 100 and reducing the need for frequent replacement of the working fluid.

[0046] Subsequently, the non-condensable gas separated by the gas-liquid separator 200 is discharged to the flare through the exhaust pipeline 210 for safe treatment, while the liquid containing organic solvents and toxic substances is sent to the waste liquid collection tank 300 through the drainage pipeline 220, and then sent to the external refining device for refining through the waste liquid external pump 310 to achieve resource recycling. On the one hand, this solves the environmental pressure caused by the large amount of water discharge, and on the other hand, it also solves the safety hazard problem when discharging water containing organic solvents and toxic substances.

[0047] That is to say, in this embodiment, hydrogenated solvent oil is used as the working fluid, and combined with the gas-liquid separator 200 and waste liquid recovery technology, the problems of increased working fluid temperature, environmental pollution and safety hazards existing in the traditional water ring vacuum pump system are successfully solved, achieving the goals of energy saving, environmental protection, safety and high efficiency.

[0048] Preferably, an inlet buffer tank 400 is also provided on the pipeline between the external production system and the liquid ring vacuum pump 100, and the inlet buffer tank 400 can provide a buffer area before the gas enters the liquid ring vacuum pump 100, which helps to smooth the gas flow and reduce the impact of gas supply fluctuations in the production system on the operation of the liquid ring vacuum pump 100. This not only protects the liquid ring vacuum pump 100 from sudden pressure changes, but also ensures that it operates under more stable conditions;

[0049] Among them, the inlet buffer tank 400 is equipped with a pressure gauge and a pressure transmitter to detect the pressure value and transmit information, so as to facilitate real-time monitoring of the gas state and adjust the operating parameters according to the actual situation to ensure the stability of the system.

[0050] Preferably, the gas-liquid separator 200 is also connected to a reflux pipeline 230, which is connected to the inlet buffer tank 400. Part of the gas discharged from the top of the gas-liquid separator 200 is discharged to the inlet buffer tank 400 through the reflux pipeline 230. A reflux regulating valve is provided on the reflux pipeline 230 to adjust the proportion and rate of the reflux gas according to actual needs.

[0051] The setting of the return line 230 has the following functions:

[0052] 1. If the discharge pressure of the gas-liquid separator 200 is higher than the specified value, the motor current will be too high and the motor will be easily burned out. At this time, the reflux regulating valve on the reflux pipeline can be manually controlled to allow part of the gas to flow back to the inlet of the liquid ring vacuum pump 100, thereby reducing the pressure of the gas-liquid separator 200;

[0053] 2. When the production system is in vacuum, the unit cannot be immediately connected to the production system when it is started. The reflux pipeline can be opened and the liquid ring vacuum pump 100 can be started to allow the gas to circulate in the unit. When the vacuum degree of the production system is reached, the valve of the production system can be slowly opened, and then the reflux regulating valve can be closed. At this time, the reflux pipeline can act as a buffer.

[0054] 3. When the liquid ring vacuum pump 100 generates a large cavitation noise, the reflux regulating valve can be opened to allow the gas to reflux to eliminate the cavitation phenomenon, thereby reducing damage to the liquid ring vacuum pump 100.

[0055] Preferably, a demister 240 is provided at the top of the gas-liquid separator 200, and the separated non-condensable gas is passed through the demister 240 to remove the liquid phase component, that is, the gas discharged from the top of the gas-liquid separator 200 is subjected to secondary separation through the demister 240, and after the liquid phase component is removed, it is discharged to the flare or reflux pipeline 230 through the exhaust pipeline 210;

[0056] On the one hand, by efficiently removing the liquid components in the gas, the possibility of harmful substances being discharged with the gas is reduced, thereby reducing the risk of environmental pollution. On the other hand, the captured liquid components can be returned to the bottom of the gas-liquid separator 200, enter the circulation system or be sent to the waste liquid collection tank 300 for re-refining, thereby achieving effective recycling of resources.

[0057] Preferably, the exhaust pipeline 210 is further connected with a magnetic oxygen analyzer 211 and a nitrogen purge pipeline 212. When the magnetic oxygen analyzer 211 detects that the oxygen content on the exhaust pipeline 210 exceeds a preset value, nitrogen is released through the nitrogen purge pipeline 212 and the exhaust regulating valve on the exhaust pipeline 210 is purged to dilute the oxygen concentration.

[0058] It should be noted here that in the case where non-condensable gases need to be discharged to the flare for combustion, maintaining an appropriate oxygen content helps to achieve a more complete and stable combustion process and reduce the generation of harmful by-products (such as carbon monoxide and incompletely burned hydrocarbons). However, when the oxygen concentration is too high, there is a risk of combustion and explosion. The combination of the magnetic oxygen analyzer 211 and the nitrogen purge system achieves an instant response to changes in oxygen content, and can take prompt measures when the oxygen content exceeds the standard to ensure the safe operation of the system.

[0059] Preferably, a liquid replenishing pipeline 250 is further included, which is connected to the gas-liquid separator 200 and is used to replenish the working liquid to keep the liquid level in the gas-liquid separator 200 at an appropriate level.

[0060] Furthermore, it also includes a gas-liquid separator liquid level control system, which is composed of a liquid level meter and a liquid level transmitter. The liquid level meter is used to detect the liquid level in the gas-liquid separator 200 in real time, and the liquid level transmitter is used to output a current signal (4-20mA) to the control system, wherein:

[0061] When the liquid level in the gas-liquid separator 200 is higher than the preset value, the liquid level transmitter outputs a corresponding high liquid level current signal to the control system, and the control system opens the discharge regulating valve disposed on the discharge pipeline 220 to realize the automatic discharge function;

[0062] When the liquid level in the gas-liquid separator 200 is lower than the preset value, the liquid level transmitter outputs a corresponding low liquid level current signal to the control system, and the control system opens the liquid replenishment switch valve arranged on the liquid replenishment pipeline to realize the function of automatic liquid replenishment.

[0063] It is worth mentioning here that the drainage pipeline 220 is composed of a manual drainage pipeline 221 and an automatic drainage pipeline 222 arranged in parallel. The two pipelines can work independently or simultaneously, providing greater operational flexibility;

[0064] In daily operation, the automatic liquid discharge pipeline 222 is mainly used for liquid discharge operation. When the liquid level in the gas-liquid separator 200 exceeds the set safety threshold, the control system automatically triggers the liquid discharge regulating valve to open and discharge the excess liquid;

[0065] When maintenance or overhaul is required or special circumstances are encountered, the manual valve on the manual drain line 221 can be used to drain the liquid, which is not restricted by the control system and is convenient for quick response.

[0066] At the same time, the control system can also control the start and stop of the waste liquid delivery pump 310 according to the liquid level high and low signals fed back by the gas-liquid separator 200. When the liquid level in the gas-liquid separator 200 is higher than the preset value, the control system starts the waste liquid delivery pump 310 to achieve automatic drainage. When the liquid level in the gas-liquid separator 200 is lower than the preset value, the control system shuts down the waste liquid delivery pump 310 to automatically stop drainage.

[0067] By setting the gas-liquid separator liquid level control system, it can be ensured that the working liquid in the gas-liquid separator 200 is always maintained within an optimal liquid level range, thereby avoiding a decrease in system performance due to an excessively high or low liquid level.

[0068] Preferably, a pump liquid supply pipeline 110 is further provided between the bottom of the gas-liquid separator 200 and the liquid inlet of the liquid ring vacuum pump 100, and a seal flushing pump 120 and a heat exchanger 130 are provided on the pump liquid supply pipeline 110, wherein:

[0069] The liquid outlet of the liquid ring vacuum pump 100, the gas-liquid separator 200, the seal flushing pump 120, the heat exchanger 130, and the liquid inlet of the liquid ring vacuum pump 100 are connected in sequence. The liquid ring vacuum pump 100 sends the extracted gas and liquid mixture into the gas-liquid separator 200 for separation. The separated liquid flows through the seal flushing pump 120 and the heat exchanger 130 through the pump liquid supply pipeline 110, and finally returns to the liquid inlet of the liquid ring vacuum pump 100, forming a continuous working liquid circulation system.

[0070] The circulation system formed by the pump liquid supply pipeline 110 cools the working fluid of the liquid ring vacuum pump 100 through the heat exchanger 130 to maintain the optimal working state of the liquid ring vacuum pump and avoid performance degradation caused by working fluid temperature fluctuation or impurities. Through the efficient cooling and circulation system, unnecessary water resource consumption and other resource waste are reduced, and effective utilization of resources is achieved;

[0071] The cooling medium of the heat exchanger 130 can be chilled water or circulating water. When chilled water is used as the cooling medium, the temperature is best controlled at 3-5°C. When circulating water is used as the cooling medium, the temperature is best controlled at less than 34°C.

[0072] Preferably, it also includes a nitrogen pressure replenishing pipeline 320, which is connected to the waste liquid collection tank 300. When the pressure in the waste liquid collection tank 300 is lower than the preset value, the internal pressure is replenished by nitrogen. In addition, a pressure relief pipeline is also provided between the waste liquid collection tank 300 and the inlet buffer tank 400. When the pressure in the waste liquid collection tank 300 is higher than the preset value, the waste liquid collection tank 300 releases the pressure to the inlet buffer tank 400 through the pressure relief pipeline, thereby ensuring that the pressure in the waste liquid collection tank 300 is always maintained within an optimal range, avoiding the degradation of system performance due to too low pressure.

[0073] Preferably, the inlet buffer tank 400, the liquid ring vacuum pump 100, the heat exchanger 130, and the seal flushing pump 120 are respectively connected to the waste liquid collection tank 300 through their own return pipelines 140, so as to discharge the condensate into the waste liquid collection tank 300 during system maintenance.

[0074] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above technical means, but also include technical schemes composed of any combination of the above technical features. The above is a specific implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

[0075] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0076] In addition, in the present invention, descriptions such as ",","one", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined with "," may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0077] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. An energy-saving closed liquid ring vacuum system suitable for petrochemical plants, characterized in that: include: A liquid ring vacuum pump is connected to an external production system, and the gas in the production system is extracted by vacuuming the liquid ring vacuum pump, wherein hydrogenated solvent oil is used as a working fluid in the liquid ring vacuum pump; A gas-liquid separator connected to the liquid ring vacuum pump, wherein the top of the gas-liquid separator is connected to an exhaust pipeline, through which the separated non-condensable gas is discharged to the flare; A waste liquid collection tank is connected to the gas-liquid separator via a liquid discharge pipeline, and the waste liquid collection tank sends the waste liquid discharged from the bottom of the gas-liquid separator to an external refining device.

2. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 1, characterized in that: An inlet buffer tank is also provided on the pipeline between the external production system and the liquid ring vacuum pump.

3. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 2, characterized in that: The gas-liquid separator is also connected to a reflux pipeline, which is connected to the inlet buffer tank. Part of the gas discharged from the top of the gas-liquid separator is discharged to the inlet buffer tank through the reflux pipeline.

4. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 1, characterized in that: A demister is provided on the top of the gas-liquid separator, and the separated non-condensable gas is passed through the demister to remove liquid components.

5. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 1, characterized in that: The exhaust pipeline is also connected to a magnetic oxygen analyzer and a nitrogen purge line. When the magnetic oxygen analyzer detects that the oxygen content on the exhaust pipeline exceeds a preset value, nitrogen is released through the nitrogen purge line and the exhaust regulating valve on the exhaust pipeline is purged to dilute the oxygen concentration.

6. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 1, characterized in that: Also included is a liquid replenishing pipeline, which is connected to the gas-liquid separator and is used to replenish the working fluid.

7. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 6, characterized in that: It also includes a gas-liquid separator liquid level control system, which is composed of a liquid level meter and a liquid level transmitter. The liquid level meter is used to detect the liquid level in the gas-liquid separator in real time, wherein: When the liquid level in the gas-liquid separator is higher than a preset value, the liquid level transmitter outputs a corresponding high liquid level current signal to the control system, and the control system opens the discharge regulating valve disposed on the discharge pipeline; When the liquid level in the gas-liquid separator is lower than a preset value, the liquid level transmitter outputs a corresponding low liquid level current signal to the control system, and the control system opens the liquid replenishment switch valve disposed on the liquid replenishment pipeline.

8. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 1, characterized in that: A pump liquid supply pipeline is also provided between the bottom of the gas-liquid separator and the liquid inlet of the liquid ring vacuum pump, and a sealing flushing pump and a heat exchanger are provided on the pump liquid supply pipeline, wherein: The liquid outlet of the liquid ring vacuum pump, the gas-liquid separator, the seal flushing pump, the heat exchanger, and the liquid inlet of the liquid ring vacuum pump are connected in sequence to form a circulation system.

9. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 1, characterized in that: It also includes a nitrogen pressure-compensating pipeline connected to the waste liquid collection tank. When the pressure in the waste liquid collection tank is lower than a preset value, the internal pressure is supplemented by nitrogen.

10. The energy-saving closed liquid ring vacuum system suitable for petrochemical equipment according to claim 2, characterized in that: A pressure relief pipeline is also provided between the waste liquid collection tank and the inlet buffer tank. When the pressure in the waste liquid collection tank is higher than a preset value, the waste liquid collection tank releases pressure to the inlet buffer tank through the pressure relief pipeline.

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