Combined flushing device for easily-coagulated high-temperature solvent pump

Abstract

The utility model discloses a combined type flushing device for an easy-to-condense high-temperature solvent pump. The combined type flushing device comprises a pump mechanical seal cavity, a Plan21 seal flushing system, a Plan21 check valve, a Plan32 seal flushing system, a flow limiting pore plate, a Plan32 check valve, a three-way valve, a Plan21 cooler and a Plan21 flushing system heat preservation layer. According to the combined type sealing flushing system, appropriate external flushing fluid is used as a mechanical sealing flushing medium in the initial stage of starting of the device, solvent media in the pump are cooled by the cooler to serve as a flushing medium after starting of the device is stable, and the temperature of the mechanical sealing working environment is appropriate while it is guaranteed that the media in the pump are clean and free of pollution; the flushing medium heat exchanger is economical and reasonable; therefore, the operation stability and reliability of the easily-coagulated high-temperature mechanical seal are improved, the energy consumption is effectively reduced, the abrasion and maintenance frequency of the mechanical seal are reduced, and the mechanical seal can stably and reliably work for a long time.

Description

Technical Field

[0001] The utility model relates to a mechanical seal flushing system for a centrifugal pump, in particular to a combined seal flushing system which flushes and cools the mechanical seal of an easy-to-freeze and high-temperature solvent pump by changing the flushing medium in the seal cavity at different operation stages in an aromatics extraction unit and similar units or similar operation conditions in a general oil refining unit. Background Art

[0002] At present, mechanical seals are widely used in pump products. According to statistics, 60% of the unplanned shutdown accidents of mechanical equipment are directly related to leaks caused by seal failures, and the mechanical seal flushing system has become an important link affecting the energy consumption, use effect and service life of mechanical seals.

[0003] Different flushing systems have different effects on energy consumption. For the mechanical seal flushing system of a centrifugal pump for transporting easy-to-freeze and high-temperature solvent media at the front end of aromatics extraction, not only is it required that the viscosity of the flushing medium can meet the requirements of mechanical seal flushing, but also energy conservation should be achieved. Regarding the influence of the medium temperature of the centrifugal pump for transporting easy-to-freeze and high-temperature solvents on the viscosity of the medium at the initial stage of plant startup, if only a self-flushing system in which the medium in the pump is cooled by an externally added cooler is adopted, due to the unstable temperature of the pumped medium at the initial stage of startup, it is difficult to control the cooling fluid of the self-flushing cooler and the influence of the ambient temperature on external factors such as the self-flushing pipeline, which may lead to an increase in the viscosity of the self-flushing medium at the outlet of the cooler or a decrease in temperature to the freezing point, thus affecting the working environment of the seal cavity or causing the seal to fail. Moreover, the flow rate of this pump is large, the pump structure is a double-end supported BB2 type centrifugal pump, and a set of seal flushing systems are required at both the pump drive end and the non-drive end, and a large amount of seal flushing is required. In the current P01 mechanical seal flushing system in the API standard, holes are opened in the high-pressure area inside the pump and led to the seal cavity. Although it can ensure that the temperature of the flushing medium is synchronized with the medium inside the pump, the larger the diameter of the hole opened inside the pump is required to ensure sufficient flushing flow rate, and the greater the influence of the larger hole diameter on the efficiency and performance of the pump itself. In addition, the auxiliary sealing ring is easily aged in a high-temperature working environment. If only P32 flushing is adopted to introduce a medium compatible with the solvent from the outside, the external flushing liquid directly enters the process liquid, resulting in high energy consumption and low energy efficiency of the flushing system.

[0004] If the temperature of the flushing medium in the seal cavity cannot be effectively ensured to be above the freezing point and have a suitable and stable viscosity, it will lead to a poor working environment for the mechanical seal, thereby accelerating the wear of the mechanical seal, hindering the rotation of the dynamic ring, increasing the energy consumption of the mechanical seal, reducing the service life of the mechanical seal, causing frequent maintenance of mechanical equipment, seriously affecting the long-term operation of production units and the maintenance operation cost of equipment. Even more seriously, when the mechanical seal is damaged, it may cause safety accidents due to the leakage of high-temperature media and have a bad impact on the environment. Summary of the Utility Model

[0005] The purpose of the present utility model is to provide a combined flushing device for an easily condensable high-temperature solvent pump, so as to solve the problems put forward in the above-mentioned background technology.

[0006] In order to achieve the above purpose, the present utility model adopts the following technical solutions: A combined flushing device for an easily condensable high-temperature solvent pump, including a pump mechanical seal cavity, a Plan21 seal flushing system, a Plan21 check valve, a Plan32 seal flushing system, an orifice plate, a Plan32 check valve, a three-way valve, a Plan21 cooler, and a Plan21 flushing system insulation layer. One end of the pump mechanical seal cavity is connected to the Plan21 seal flushing system. The end of the Plan21 seal flushing system away from the pump mechanical seal cavity is connected to a Plan21 check valve. The other end of the Plan21 check valve is connected to a three-way valve. A Plan32 check valve, an orifice plate, and a Plan32 seal flushing system are sequentially arranged at the end of the three-way valve perpendicular to the Plan21 seal flushing system. The other end of the three-way valve is connected to a Plan21 cooler, and a Plan21 flushing system insulation layer is arranged outside the Plan21 cooler.

[0007] Preferably, both the Plan21 seal flushing system and the Plan32 seal flushing system are provided with channels inside and are connected to the three-way valve through the channels.

[0008] Preferably, the outer end of the Plan21 cooler is also provided with a channel, and the Plan21 flushing system insulation layer is arranged at the outer end of the Plan21 cooler channel.

[0009] Preferably, the Plan32 seal flushing system can introduce external seal flushing fluid, and the seal flushing fluid can be compatible with the medium in the pump and can be a high-temperature and stable fluid.

[0010] Preferably, a Plan21 / Plan32 flushing medium common inlet is arranged at the position of the outer side of the pump mechanical seal cavity close to the Plan21 seal flushing system.

[0011] Preferably, the Plan21 / Plan32 flushing medium common inlet is connected to the Plan21 cooler channel, and the temperature inside is 40°.

[0012] Preferably, a pump is connected to the right end of the pump mechanical seal cavity, a solvent inlet is connected to the right end of the pump, and a solvent outlet is arranged at the top.

[0013] Compared with the prior art, the beneficial effects of the present utility model are:

[0014] 1. Reduce the risk of mechanical seal leakage and failure caused by the increase in viscosity or solidification of the Plan21 flushing medium at the initial stage of startup;

[0015] 2. The Plan21 self-flushing system is convenient and direct to cite, reducing energy consumption.

[0016] 3. After normal operation, the flushing medium is always the medium inside the pump, without pollution to the easily condensable high-temperature solvent.

[0017] 4. It reduces the problems of high long-term operation energy consumption and low energy efficiency of Plan32.

[0018] 5. The system where the Plan32 flushing liquid shares the Plan21 cooler expands the range of media and temperature for the external flushing liquid of Plan32.

[0019] 6. It reduces the temperature of the flushing medium, effectively preventing the aging of the auxiliary sealing ring.

[0020] 7. The two systems can achieve non-reflux and cut-off flow switching, with convenient, safe and reliable operation.

[0021] 8. The insulation layer of the Plan21 flushing system effectively reduces the impact on the flushing system in the low-temperature season.

[0022] 9. The use of the orifice plate ensures the stability of the pressure and flow rate of the two systems.

[0023] 10. The sequential use of the two systems can reduce accidents and maintenance rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an easily condensable high-temperature mechanical seal combined flushing device.

[0025] In the figure: pump mechanical seal cavity - 1, Plan21 seal flushing system - 2, Plan21 check valve - 3, Plan32 seal flushing system - 4, orifice plate - 5, Plan32 check valve - 6, three-way valve - 7, Plan21 cooler - 8, insulation layer of Plan21 flushing system - 9. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to further explain the technical solution of the present invention, it will be elaborated in detail through specific embodiments below.

[0027] Please refer to Figure 1, the present utility model provides a combined flushing device for an easily condensable high-temperature solvent pump, which includes a pump mechanical seal cavity 1, a Plan21 seal flushing system 2, a Plan21 check valve 3, a Plan32 seal flushing system 4, a restrictor orifice 5, a Plan32 check valve 6, a three-way valve 7, a Plan21 cooler 8 and a Plan21 flushing system thermal insulation layer 9. The right end of the pump mechanical seal cavity 1 is connected to a pump, the right end of the pump is connected to a solvent inlet, and the top is provided with a solvent outlet. One end of the outside of the pump mechanical seal cavity 1 is connected to the Plan21 seal flushing system 2. A Plan21 / Plan32 flushing medium common inlet is provided near the Plan21 seal flushing system 2, which is beneficial to the flow of the flushing liquid, and the temperature inside is maintained at 40°. A channel through which the flushing liquid can flow is provided in the Plan21 seal flushing system 2. One end of the channel of the Plan21 seal flushing system 2 is connected to the three-way valve 7, and a Plan21 check valve 3 is provided outside near the three-way valve 7.

[0028] Please refer to Figure 1 , the present utility model provides a combined flushing device for an easily condensable high-temperature solvent pump. A Plan32 check valve 6, a restrictor orifice 5 and a Plan32 seal flushing system 4 are sequentially provided at one end of the three-way valve 7 perpendicular to the Plan21 seal flushing system 2. The Plan32 seal flushing system 4 can introduce external seal flushing liquid. Among them, the seal flushing liquid can be compatible with the medium in the pump and can be a high-temperature and stable fluid, which improves stability. A channel through which the flushing liquid can flow is also provided in the Plan32 seal flushing system 4. The channel of the Plan32 seal flushing system 4 sequentially passes through the restrictor orifice 5, the Plan32 check valve 6 and is connected to the three-way valve 7. The Plan21 seal flushing system 2 or the Plan32 seal flushing system 4 can be opened or closed through the three-way valve 7.

[0029] Please refer to Figure 1 , the present utility model provides a combined flushing device for an easily condensable high-temperature solvent pump. The other end of the three-way valve 7 is connected to a Plan21 cooler 8. The Plan21 cooler 8 is filled with a coolant, which can cool the flushing liquid. Further, a channel through which the flushing liquid can flow is also provided at the outer end of the Plan21 cooler 8, and a Plan21 flushing system thermal insulation layer 9 is provided outside the channel of the Plan21 cooler 8, which can protect the flushing liquid in the channel of the Plan21 cooler 8, and the channel of the Plan21 cooler 8 is connected to the Plan21 / Plan32 flushing medium common inlet, and the flushing liquid can be introduced into the pump mechanical seal cavity 1.

[0030] The working principle is as follows:

[0031] Before the start of the easy-to-coagulate high-temperature solvent centrifugal pump, the three-way valve 7 opens the 4 channels of the Plan32 seal flushing system and closes the 2 channels of the Plan21 seal flushing system. The seal flushing liquid is the external flushing liquid provided by the Plan32 flushing liquid inlet. The external flushing liquid is compatible with the medium in the pump and can be a high-temperature and stable fluid. After passing through the orifice plate 5, the Plan32 check valve 6, the three-way valve 7 and the Plan21 cooler 8 for cooling, the external flushing liquid enters the pump mechanical seal cavity 1 from the Plan21 / Plan32 flushing medium common inlet, and finally enters the pump from the seal cavity. The Plan32 seal flushing system 4 is officially enabled, and the temperature of the Plan21 / Plan32 flushing medium common inlet is 40°C at this time;

[0032] After the device starts up normally, by switching the three-way valve 7, the 2 channels of the Plan21 seal flushing system are opened and the 4 channels of the Plan32 seal flushing system are closed. The seal flushing liquid is led out from the solvent outlet through the Plan21 flushing liquid outlet. At this time, the temperatures in the Plan21 flushing liquid outlet and the solvent outlet are both 175°C. After the seal flushing liquid is led out, it passes through the Plan21 check valve 3, the three-way valve 7 and the Plan21 cooler 8 for cooling, and enters the pump mechanical seal cavity 1 from the Plan21 / Plan32 flushing medium common inlet under the protection of the Plan21 flushing system heat preservation layer 9, and finally enters the pump from the pump mechanical seal cavity 1. The Plan21 seal flushing system 2 is officially enabled, which can effectively reduce the energy consumption of the mechanical seal flushing system during normal operation. The introduced medium is directly pollution-free, ensuring the stability of the pump flushing medium in the initial stage of startup, and effectively avoiding seal failure leakage caused by the ineffectiveness of the mechanical seal flushing system in the early stage of startup. The combined use of the two systems is convenient to operate, effectively reducing the accident rate and maintenance cost.

[0033] The above are only the preferred examples of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A combined flushing device for a high-temperature solvent pump prone to coagulation, characterized in that: It includes a pump mechanical seal cavity (1), a Plan21 seal flushing system (2), a Plan21 check valve (3), a Plan32 seal flushing system (4), a restrictor orifice (5), a Plan32 check valve (6), a three-way valve (7), a Plan21 cooler (8) and a Plan21 flushing system thermal insulation layer (9). One end of the pump mechanical seal cavity (1) is connected to the Plan21 seal flushing system (2). The end of the Plan21 seal flushing system (2) far from the pump mechanical seal cavity (1) is connected to the Plan21 check valve (3). The other end of the Plan21 check valve (3) is connected to the three-way valve (7). The end of the three-way valve (7) perpendicular to the Plan21 seal flushing system (2) is successively provided with a Plan32 check valve (6), a restrictor orifice (5) and a Plan32 seal flushing system (4). The other end of the three-way valve (7) is connected to the Plan21 cooler (8). The outside of the Plan21 cooler (8) is provided with a Plan21 flushing system thermal insulation layer (9).

2. The combined flushing device for an easily coagulable high-temperature solvent pump according to claim 1, wherein: Both the Plan21 seal flushing system (2) and the Plan32 seal flushing system (4) are provided with channels inside and are connected to the three-way valve (7) through the channels.

3. The combined flushing device for an easily condensable high-temperature solvent pump according to claim 1, wherein: The outer end of the Plan21 cooler (8) is also provided with a channel, and the Plan21 flushing system thermal insulation layer (9) is arranged at the outer end of the channel of the Plan21 cooler (8).

4. The combined flushing device for an easily condensable high-temperature solvent pump according to claim 1, characterized in that: The Plan32 seal flushing system (4) can introduce an external seal flushing liquid, and the seal flushing liquid can be compatible with the medium in the pump and can be a high-temperature and stable fluid in nature.

5. The combined flushing device for an easily condensable high-temperature solvent pump according to claim 1, characterized in that: A Plan21 / Plan32 flushing medium common inlet is provided at a position on the outside of the pump mechanical seal cavity (1) close to the Plan21 seal flushing system (2).

6. The combined flushing device for an easily condensable high-temperature solvent pump according to claim 5, characterized in that: The Plan21 / Plan32 flushing medium common inlet is connected to the channel of the Plan21 cooler (8), and the temperature inside is 40°C.

7. The combined flushing device for an easily condensable high-temperature solvent pump according to claim 1, characterized in that: The right end of the pump mechanical seal cavity (1) is connected to a pump. The right end of the pump is connected to a solvent inlet, and the top is provided with a solvent outlet.

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