Cooling EG circulating device

Abstract

The utility model discloses a cooling EG circulating device which comprises a cooling EG storage tank, the top of the cooling EG storage tank is provided with a clean EG inlet and a liquid level metering header connector, the liquid level metering header connector is connected with a liquid level metering header, the upper end and the lower end of the liquid level metering header are respectively provided with a liquid level meter connecting pipe orifice, and the liquid level meter connecting pipe orifices are externally connected with a liquid level meter. The method is sensitive to the change of the total amount of circulating EG in the cooling EG storage tank, whether leakage exists in the mechanical seal or not can be judged in time, and the stability is improved; the flow and the pressure of cooling EG entering the mechanical seal cooling system can be adjusted; impurities can be prevented from entering a sealing cavity of the mechanical seal, and the service life of the mechanical seal is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical equipment, and more specifically, to a cooling EG circulation device. Background Technique

[0002] In polyester production, mechanical seals are flushed and cooled with ethylene glycol. In order to reduce the investment cost, a simplified PLAN54 flushing scheme is mostly adopted for the final polymerization mechanical seal. Ethylene glycol flows through the seal cavity of the final polymerization mechanical seal and lubricates and cools the seal end face. The ethylene glycol EG flowing out of the mechanical seal flows into the final polymerization hot well, and the cooling ethylene glycol EG is not recycled.

[0003] In the prior art, there is also a design of a liquid storage tank for a mechanical seal circulating cooling system. For example, the Chinese patent publication number is CN 212374067 U, and the publication date is January 19, 2021. The name of the utility model is a liquid storage tank for a mechanical seal external circulation cooling system. This application case is provided with a resistance induction probe at the bottom of the tank to detect whether there is a leak in the cooling coil, and a liquid outlet filter is also connected to the liquid outlet pipe opening, which can prevent impurities in the liquid storage tank from entering the mechanical seal cavity. However, the induction of the resistance induction probe at the bottom is not sensitive enough, and in addition, the liquid storage tank is not sensitive enough to the change of the liquid level. If a leak occurs in the mechanical seal, it cannot be detected and dealt with in time. Content of the Utility Model

[0004] The utility model overcomes the deficiency that the liquid storage tank cannot be detected and dealt with in time when a leak occurs in the mechanical seal in the prior art, and provides a cooling EG circulation device, which is sensitive to the change of the liquid level in the liquid storage tank and can timely determine whether there is a leak in the mechanical seal.

[0005] In order to solve the above technical problems, the utility model adopts the following technical scheme: a cooling EG circulation device, including a cooling EG storage tank, a clean EG inlet and a liquid level measurement header interface are arranged at the top of the cooling EG storage tank, the liquid level measurement header interface is connected with a liquid level measurement header, liquid level gauge connection pipe orifices are arranged at both the upper and lower ends of the liquid level measurement header, and a liquid level gauge is externally connected to the liquid level gauge connection pipe orifice.

[0006] The utility model is provided with a liquid level measurement header, and liquid level gauges are externally connected to both the upper and lower ends of the liquid level measurement header. The liquid level gauges maintain the cooling EG in the liquid level measurement header within a certain height range through a switch cooling EG liquid level control valve. At the same time, this setting is sensitive to the change of the total amount of circulating EG in the cooling EG storage tank and can timely determine whether there is a leak in the mechanical seal.

[0007] Preferably, a cooling EG liquid level control valve is externally connected to the clean EG inlet, and an interlock control is provided between the liquid level gauge and the cooling EG liquid level control valve.

[0008] The EG that has been depressurized to the required level enters the cooling EG storage tank through the clean EG inlet. The level gauge controls the total amount entering by controlling the opening and closing of the cooling EG level control valve.

[0009] Preferably, a cooling EG return liquid pipe orifice is provided at the upper part of the side of the cooling EG storage tank, and a cooling EG outlet is provided at the lower part of the side of the cooling EG storage tank.

[0010] After the cooling EG that has completed cooling the mechanical seal enters the cooling EG storage tank through the cooling EG return liquid pipe orifice for re-cooling, the cooling EG that has been cooled by the cooling EG storage tank flows out of the cooling EG storage tank through the cooling EG outlet.

[0011] Preferably, the outside of the cooling EG outlet is connected to a cooling EG circulation pump, and a filter is connected in series after the cooling EG circulation pump.

[0012] After the cooling EG that has been cooled in the cooling EG storage tank flows out of the cooling EG storage tank through the cooling EG outlet, the cooling EG circulation pump conveys the cooling EG to the mechanical seal that needs to be cooled. Connecting a filter in series after the cooling EG circulation pump can prevent impurities from entering the mechanical seal cavity.

[0013] Preferably, a balance pipe orifice is provided between the cooling EG return liquid pipe orifice and the cooling EG outlet.

[0014] The balance pipe orifice is connected to the mechanical seal cooling system, which can change the flow rate and pressure of the cooling EG in the mechanical seal cooling system.

[0015] Preferably, a cooling pipe coil is provided inside the cooling EG storage tank, and the water inlet and outlet of the cooling pipe coil are both provided at the bottom of the cooling EG storage tank. The cooling coil is used to fully cool the EG in the cooling EG storage tank.

[0016] Preferably, a cooling EG drain port is provided at the bottom of the cooling EG storage tank, and the cooling EG drain port is connected to the final polymerization hot well through a process pipeline.

[0017] When it is necessary to replace or drain the cooling EG in the cooling EG storage tank, it can be achieved through the cooling EG drain port.

[0018] Preferably, a cooling EG storage tank liquid level balance pipe is provided after the cooling EG drain port, and the cooling EG drain port and the cooling EG storage tank liquid level balance pipe are arranged in parallel.

[0019] The cooling EG storage tank liquid level balance pipe can assist the level gauge in controlling the liquid level in the cooling EG storage tank. The cooling EG drain port and the cooling EG storage tank liquid level balance pipe are designed in parallel, and the replacement or drainage of the cooling EG in the cooling EG storage tank is achieved through the control of different isolation valves.

[0020] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0021] Liquid level gauges are provided at both the upper and lower ends of the liquid level measurement header, which are sensitive to the change in the total amount of circulating EG in the cooling EG storage tank, and can timely determine whether there is leakage in the mechanical seal to ensure the safety and stability of the device;

[0022] The setting of the balance pipe orifice can adjust the flow rate and pressure of the cooling EG entering the mechanical seal cooling system, and better cool the mechanical seal;

[0023] The setting of the cooperation between the liquid level gauge and the cooling EG liquid level control valve, and the setting of the liquid level balance pipe of the cooling EG storage tank can better control the liquid level in the cooling EG storage tank in cooperation with the liquid level gauge, and further improve the stability;

[0024] The setting of the cooling EG circulation pump and the filter can prevent impurities from entering the mechanical seal cavity and extend the service life of the mechanical seal. Description of the Drawings

[0025] Figure 1 is a process schematic diagram of the utility model.

[0026] Figure 2 is an assembly schematic diagram of the cooling EG storage tank and the liquid level measurement header of the utility model.

[0027] In the figure: 1-1, cooling EG storage tank; 1-11, cooling EG storage tank housing; 1-12, cooling coil; 1-12-1, water inlet; 1-12-2, water outlet; 1-13, clean EG inlet; 1-14, liquid level measurement header interface; 1-15, cooling EG outlet; 1-16, cooling EG return liquid pipe orifice; 1-17, balance pipe orifice; 1-18, cooling EG drain port; 1-2, liquid level measurement header; 1-21, short pipe; 1-22, liquid level gauge connection pipe orifice one; 1-23, liquid level gauge connection pipe orifice two; 1-24, docking flange; 1-25, exhaust valve; 1-3, liquid level gauge; 1-4, cooling EG liquid level control valve; 1-5, cooling EG circulation pump; 1-6, filter; 1-7, cooling EG storage tank liquid level balance pipe; 1-71, isolation valve one; 1-72, isolation valve two. Detailed Embodiments

[0028] The technical solutions of the present utility model will be further specifically described below through specific embodiments in conjunction with the drawings:

[0029] Example 1: In production, ethylene glycol is used for flushing and cooling in mechanical seals. To reduce investment costs, a simplified PLAN54 flushing scheme is mostly adopted for the final polymerization mechanical seal. That is, a branch pipeline is taken from the fresh EG main pipeline of the production system. The fresh EG is pressurized to 1 MPa by a transfer pump and then reduced to 0.2 MPa by a self-operated regulating valve. The ethylene glycol flows through the seal cavity of the final polymerization mechanical seal and lubricates and cools the seal end face. The ethylene glycol EG flowing out of the mechanical seal flows into the final polymerization hot well, and the cooling ethylene glycol EG is not recycled. After the mechanical seal operates for a long time, due to the wear of the seal end face and the reduction of the elastic force of the spring, liquid leakage will occur at the seal end face of the mechanical seal. The greater the pressure of the cooling ethylene glycol EG, the greater the leakage amount of the seal end face. When the seal end face leaks severely, it will cause the device to shut down.

[0030] Therefore, the present utility model provides a cooling EG circulation device, which is used to provide cooling EG for the mechanical seal cooling system and realizes the recycling of cooling EG. The present utility model includes a cooling EG storage tank 1-1. A clean EG inlet 1-13 and a liquid level metering header interface 1-14 are provided at the top of the cooling EG storage tank 1-1. A cooling EG liquid level control valve 1-4 is externally connected to the clean EG inlet 1-13. The liquid level metering header interface 1-14 is connected to a liquid level metering header 1-2 through a docking flange 1-24. The liquid level metering header 1-2 is a short pipe 1-21 with a small diameter and is vertically arranged. A liquid level gauge connection nozzle one 1-22 is provided at the upper end of the short pipe 1-21, and a liquid level gauge connection nozzle two 1-23 is provided at the lower end of the short pipe 1-21. Both the liquid level gauge connection nozzle one 1-22 and the liquid level gauge connection nozzle two 1-23 are externally connected to a liquid level gauge 1-3. The liquid level gauge 1-3 and the cooling EG liquid level control valve 1-4 are interlocked. An exhaust valve 1-25 is provided at the top of the liquid level metering header 1-2, and the exhaust valve 1-25 is fixedly connected to the liquid level metering header 1-2 through a flange. A pressure sensor is also provided on the liquid level metering header 1-2. Regarding the liquid level metering header 1-2, in this embodiment, the measurement principle of a double-flange liquid level gauge is adopted: The double-flange differential pressure liquid level gauge is generally used to measure the liquid level of a closed container. The double-flange liquid level gauge mainly applies the U-shaped tube principle, that is, the upper flange is connected to the gas phase space, and the lower flange is connected to the liquid phase space. In this way, the liquid level of the liquid level gauge is always the same as the liquid level of the container. The magnitude of the pressure generated by the gravity of the liquid on the tank wall is used to detect the height of the liquid level in the tank. Therefore, in this embodiment, the liquid level metering header 1-2 is sensitive to the change in the total amount of circulating EG in the cooling EG storage tank 1-1, and can timely determine whether there is leakage in the mechanical seal. At the same time, the liquid level gauge 1-3 maintains the cooling EG in the liquid level metering header 1-2 within a certain height range by switching the cooling EG liquid level control valve 1-4.

[0031] In this embodiment, the cooling EG storage tank 1-11 is a vertical barrel-shaped container with a conical bottom and a flat top. Inside the cooling EG storage tank 1-1, there is a cooling coil 1-12. The water inlet 1-12-1 and the water outlet 1-12-2 of the cooling coil 1-12 are both arranged at the bottom of the cooling EG storage tank 1-1, which is convenient for fully cooling the cooling EG. A cooling EG outlet 1-15 is arranged at the lower part of the cylindrical barrel of the cooling EG storage tank 1-1, and a cooling EG return liquid pipe orifice 1-16 is arranged at the upper part of the cylindrical barrel of the cooling EG storage tank 1-1, which can ensure that all the circulating cooling EG passes through the cooling. The cooling EG outlet 1-15 can be connected to the inlet pipe through a process pipeline. The inlet pipe can be connected to multiple mechanical seals at the same time, and the cooling EG is transported into one or more mechanical seal cooling systems through the inlet pipe for cooling work; the cooling EG return liquid pipe orifice 1-16 can be connected to the return pipe through a process pipeline, and the cooling EG that has completed the cooling work in one or more mechanical seal cooling systems enters the cooling EG storage tank 1-1 through the return pipe for re-cooling and recycling.

[0032] Embodiment 2: In this embodiment, a cooling EG circulation pump 1-5 and a filter 1-6 are connected in series on the process pipeline between the cooling EG outlet 1-15 and the inlet pipe. The cooling EG circulation pump 1-5 transports the cooling EG in the cooling EG storage tank 1-1 to the inlet pipe, and the filter 1-6 can filter the impurities in the cooling EG storage tank 1-1 to prevent the impurities from entering the mechanical seal cavity and damaging the mechanical seal, thereby reducing the service life of the mechanical seal.

[0033] In addition, a balance pipe orifice 1-17 is arranged between the cooling EG outlet 1-15 and the cooling EG return liquid pipe orifice 1-16 on the cylindrical barrel of the cooling EG storage tank 1-1. The balance pipe orifice 1-17 is connected to the balance pipe through a process pipeline. The cooling EG is transported between the balance pipe and the mechanical seal cooling system, which can change the flow rate and pressure of the cooling EG entering the mechanical seal cooling system. The balance pipe can also be connected to multiple mechanical seals at the same time. When the balance pipe is connected to multiple mechanical seals that need to be cooled at the same time, the different requirements of different mechanical seals for the flow rate and pressure of the cooling EG can be met through the balance pipe. The balance pipe orifice 1-17 cooperates with the inlet pipe orifice and the return pipe orifice. If the flow rate or pressure of the cooling EG in the mechanical seal cooling system is too small, at this time, the balance pipe orifice 1-17 needs to output the cooling EG to adjust the cooling EG in the mechanical seal cooling system. If the flow rate or pressure of the cooling EG in the mechanical seal cooling system is too large, the mechanical seal cooling system will input the excess cooling EG into the balance pipe and transport it back to the cooling EG storage tank 1-1 through the balance pipe orifice 1-17.

[0034] Example 3: In this example, a cooling EG drain port 1-18 is provided at the bottom of the cooling EG storage tank 1-1. A cooling EG storage tank liquid level balancing pipe 1-7 is connected in parallel to the cooling EG drain port 1-18. The top height of the cooling EG storage tank liquid level balancing pipe 1-7 is between the pipe orifice of two liquid level gauges. The outlet of the cooling EG storage tank liquid level balancing pipe 1-7 is connected to the final polymerization hot well through a process pipeline. The replacement or drainage of the cooling EG inside the cooling EG storage tank 1-1 is achieved by the opening and closing of different isolating valves. The cooling EG can be replaced irregularly through the cooling EG storage tank liquid level balancing pipe 1-7, which can ensure the cleanliness of the cooling EG circulation system. During normal operation, isolating valve 1 1-71 is opened and isolating valve 2 1-72 is closed. When the system EG is replaced or drained during shutdown, isolating valve 2 1-72 is opened, and isolating valve 1 1-71 can be opened or closed as needed.

[0035] The following is a detailed introduction to the flow process of the cooling EG in the cooling EG storage tank 1-1:

[0036] Open the cooling EG liquid level control valve 1-4. After the cooling EG is uniformly depressurized, the cooling EG enters the cooling EG storage tank 1-1 through the clean EG inlet 1-13 provided at the top of the cooling EG storage tank 1-1. After entering the cooling EG storage tank 1-1, the cooling EG falls to the bottom. At this time, cooling water starts to enter the water inlet 1-12-1 of the cooling coil 1-12 at the bottom of the cooling EG storage tank 1-1. After circulating once in the cooling coil 1-12, the cooling water will flow out from the water outlet 1-12-2 of the cooling coil 1-12. During this process, the cooling EG that has fallen to the bottom will be cooled by the cooling water in the cooling coil 1-12. The cooling water continuously enters from the water inlet 1-12-1 and flows out from the water outlet 1-12-2, keeping the cooling coil 1-12 always filled with cooling water, so as to fully cool the cooling EG in the cooling EG storage tank 1-1.

[0037] The cooled EG after compression and depressurization continuously enters the cooling EG storage tank 1-1 through the clean EG inlet 1-13. When the cooling EG storage tank 1-1 is filled, the cooling EG will enter the liquid level measurement header 1-2 through the liquid level measurement header interface 1-14. The liquid level gauges 1-3 provided at the upper and lower ends of the liquid level gauge header will record the liquid level. According to the data recorded by the liquid level gauge 1-3, if the liquid level is too high, the cooling EG liquid level control valve 1-4 is closed to stop the cooling EG from entering again, thereby reducing the liquid level; if the liquid level is too low, the cooling EG liquid level control valve 1-4 is opened to add new cooling EG into the cooling EG storage tank 1-1, thereby increasing the liquid level height.

[0038] After the liquid level of the cooling EG entering the liquid level measuring header 1-2 stabilizes, open the cooling EG outlet 1-15 at the lower part of the cylindrical body of the cooling EG storage tank 1-1 and the balance pipe orifice 1-17 at the upper part of the cylindrical body of the cooling EG storage tank 1-1. The cooling EG will flow from the cooling outlet into the inlet pipe, be transported towards the mechanical seal cooling system after passing through the cooling EG circulation pump 1-5, and then enter the filter 1-6 connected in series with the cooling EG circulation pump 1-5 to filter the cooling EG. After the filtration is completed, the cooling EG will flow along the inlet pipe into the mechanical seal cooling system for cooling work. At the same time, if the inlet pipe is connected to multiple mechanical seal cooling systems, according to the requirements of different mechanical seals, the cooling EG in the cooling storage tank will enter the balance pipe from the balance pipe orifice 1-17 and be transported through the balance pipe into the mechanical seal cooling system that needs to change the flow rate and pressure. If the flow rate or pressure of the cooling EG in the mechanical seal cooling system is too small, at this time, the balance pipe orifice 1-17 needs to output the cooling EG to adjust the cooling EG in the mechanical seal cooling system. If the flow rate or pressure of the cooling EG in the mechanical seal cooling system is too large, the mechanical seal cooling system will input the excess cooling EG into the balance pipe and transport it back to the cooling EG storage tank 1-1 through the balance pipe orifice 1-17.

[0039] After a certain period of time, open the cooling EG return liquid orifice 1-16 at the upper part of the cylindrical body of the cooling EG storage tank 1-1. The cooling EG that has completed the mechanical seal cooling work will flow back from the return pipe and flow back into the cooling EG storage tank 1-1 through the cooling EG return liquid orifice 1-16, and will be cooled again by the cooling coil 1-12. After the re-cooling is completed, it will flow into the inlet pipe from the cooling EG outlet 1-15 and then enter the mechanical seal cooling system again for the cooling area work.

[0040] During this process, the liquid level of the cooling EG in the liquid level measuring header 1-2 is continuously controlled by the liquid level gauge 1-3 to switch the cooling EG liquid level control valve 1-4. If there is a leakage in the mechanical seal, the liquid level of the cooling EG in the liquid level measuring header 1-2 will immediately change abnormally. Then, depending on the situation, the flow rate and pressure of the cooling EG can be adjusted through the balance pipe orifice 1-17, or the cooling EG can be replaced in a timely manner. If it is serious, it can also be detected in a timely manner for shutdown inspection, thereby extending the service life of the mechanical seal.

[0041] During the above process, the isolating valve 1 1-71 is always in the open state, and the isolating valve 2 1-72 is always in the closed state. When the system EG needs to be replaced or drained during shutdown, open the isolating valve 2 1-72, and the isolating valve 1 1-71 can be either open or closed. Then, it can be drained into the end polymerization hot well through the cooling EG drain port 1-18 at the bottom of the cooling EG storage tank 1-1.

[0042] Therefore, the beneficial effects produced by the present utility model are as follows: Level gauges 1-3 are provided at both the upper and lower ends of the liquid level measurement header 1-2, which are sensitive to changes in the total amount of circulating EG in the cooling EG storage tank 1-1, and can timely determine whether there is leakage in the mechanical seal to ensure the safety and stability of the device; the setting of the balance pipe orifice 1-17 can control the flow rate and pressure of the cooling EG entering the mechanical seal cooling system. If the flow rate or pressure of the cooling EG in the mechanical seal cooling system is too small, the cooling EG is output through the balance pipe orifice 1-17 to adjust the cooling EG in the mechanical seal cooling system. If the flow rate or pressure of the cooling EG in the mechanical seal cooling system is too large, the mechanical seal cooling system will input the excess cooling EG into the balance pipe and transport it back into the cooling EG storage tank 1-1 through the balance pipe orifice 1-17 to better meet the cooling conditions required by the mechanical seal; the cooperation between the level gauge 1-3 and the cooling EG level control valve 1-4, as well as the setting of the cooling EG storage tank liquid level balance pipe 1-7, can better control the liquid level in the cooling EG storage tank 1-1 in cooperation with the level gauge 1-3, further improving the stability; the setting of the cooling EG circulation pump 1-5 and the filter 1-6 can prevent impurities from entering the mechanical seal cavity and extend the life of the mechanical seal; the cooling EG is periodically replaced through the cooling EG storage tank liquid level balance pipe 1-7, which can ensure the cleanliness of the cooling EG circulation system.

[0043] The embodiments described above are only the preferred solutions of the present utility model, and do not impose any form of limitation on the present utility model. There are other variations and modifications without exceeding the technical solutions recorded in the claims.

Claims

1. A cooling EG circulation device, characterized in that: It comprises a cooling EG storage tank, wherein a clean EG inlet and a liquid level metering manifold interface are arranged on the top of the cooling EG storage tank, wherein the liquid level metering pipe interface is connected to the liquid level metering manifold, wherein both upper and lower ends of the liquid level metering manifold are provided with liquid level gauge connecting pipe ports, and the liquid level gauge connecting pipe ports are externally connected to a liquid level gauge.

2. The cooling EG circulation device according to claim 1, characterized in that: The clean EG inlet is externally connected to a cooling EG liquid level control valve, and the liquid level meter and the cooling EG liquid level control valve are interlocked.

3. The cooling EG circulation device according to claim 1 or 2, characterized in that: A cooling EG liquid return pipe port is arranged at the upper part of the side of the cooling EG storage tank, and a cooling EG outlet is arranged at the lower part of the side of the cooling EG storage tank.

4. The cooling EG circulation device according to claim 3, characterized in that: The cooling EG outlet is connected to a cooling EG circulation pump, and a filter is connected in series after the cooling EG circulation pump.

5. The cooling EG circulation device according to claim 4, characterized in that: A balance pipe opening is provided between the cooling EG liquid return pipe opening and the cooling EG outlet.

6. The cooling EG circulation device according to claim 1 or 2, characterized in that: A cooling pipe tray is provided inside the cooling EG storage tank, and a water inlet and a water outlet of the cooling pipe tray are both arranged at the bottom of the cooling EG storage tank.

7. The cooling EG circulation device according to claim 1 or 2, characterized in that: A cooling EG drain port is provided at the bottom of the cooling EG storage tank, and the cooling EG drain port is connected to the final heat collection well through a process pipeline.

8. The cooling EG circulation device according to claim 7, characterized in that: A cooling EG tank liquid level balance pipe is arranged behind the cooling EG drain port, and the cooling EG drain port and the cooling EG tank liquid level balance pipe are arranged in parallel.

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