Device and method for forced cooling and paraffin injection to seal the inlet and outlet pipelines of catalytic oil slurry pumps

Abstract

The present invention discloses a device and method for forced cooling and paraffin injection to seal the inlet and outlet pipelines of a catalytic oil slurry pump, which belongs to the technical field of petrochemical equipment maintenance. The method comprises the following steps: adding solid paraffin to a container filled with paraffin, heating the container filled with paraffin by a heating mechanism, and converting the paraffin therein into liquid; then injecting the liquid paraffin into an oil slurry unit; forcing the relevant pipelines of the oil slurry unit to cool by a cooling mechanism, waiting for the paraffin to solidify, and achieving physical sealing of the internal leakage part of the oil slurry unit by the solidification of the paraffin. The device of the present invention is used to quickly and quantitatively inject paraffin into the oil slurry pump (liquid paraffin also enters the inlet and outlet pipelines through the inlet and outlet valves of the internal leakage), and putting the inlet and outlet pipelines into forced cooling measures. By utilizing the characteristics of the high solidification temperature of paraffin and the fact that the components will not contaminate the catalytic product, the paraffin is quickly solidified, and the physical sealing of the internal leakage part is achieved cleanly, thereby making the oil slurry pump reach a safe maintenance condition.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical equipment maintenance, and particularly relates to a device and method for forced cooling, paraffin injection and plugging of catalytic oil slurry pump inlet and outlet pipelines. Background Art

[0002] The catalytic cracking unit is a core component of an oil refinery, significantly impacting its material, heat, and fuel balances. It plays a crucial role in the overall refining process. After entering the riser reactor, the catalytic feedstock, along with the regenerated catalyst, passes through it at high speed, completing the catalytic cracking reaction within seconds. Typically, a cyclone separator at the riser reactor outlet rapidly separates the post-reaction mixture from the catalyst. The regenerated catalyst then enters the regenerator for regeneration, while the mixed oil and gas enter the fractionation tower for product separation. Technological advances have continuously improved the separation efficiency of the cyclone separator at the riser reactor outlet, reducing the amount of solid catalyst particles entering the oil and gas. However, a certain amount of solid catalyst particles is still unavoidable in the mixed oil and gas. Sinopec stipulates that the solids content in the slurry oil must be controlled at ≤6 g / L. These catalyst particles, upon entering the fractionation tower, will flow along with the heavy components to the bottom of the fractionation tower, becoming solid particles mixed with the slurry oil. During normal production, slurry oil is pumped from the bottom of the distillation tower by a slurry pump and exchanged with the catalytic unit's raw materials to achieve thermal balance within the distillation tower. High-temperature slurry oil containing solid particles flows at high speed through the system, causing erosion and wear on the slurry pump, pipelines, valves, and other components. This wear can cause erosion and thinning of equipment pipelines, potentially leading to leaks and fires. It can also cause wear on valve plates in the slurry pump's inlet and outlet valves, preheating valves, and other components, causing internal leakage, making it impossible to safely isolate the slurry pump and hindering maintenance. These issues have become a major concern for the long-term operation of catalytic units.

[0003] To prevent solid particle wear on slurry systems, existing technologies have implemented targeted design and material selection measures. For example, Cr5Mo is used in slurry pipelines (including inlet and outlet pipelines and preheating pipelines) to improve pipeline wear resistance; wear-resistant linings are used in slurry pumps to improve pump wear resistance; and wear-resistant valve plates are used in slurry pump inlet and outlet valves to improve wear resistance. While these measures have improved the wear resistance of equipment and pipelines, the presence of solid catalyst particles still results in significant wear. This is especially true at the high outlet flow rate of the slurry pump, which in turn causes more severe wear on the outlet valve plates and increases the risk of internal leakage. In extreme cases, internal leakage can also occur in the inlet valve, creating challenges for the safe inspection and maintenance of slurry pumps.

[0004] CN103982739B discloses a high-temperature slurry pump preheating process, which introduces clean recycled oil (temperature 300°C) without catalyst particles as the preheating medium, and uses a flow-limiting orifice to ensure that the preheating medium flow rate is ≯5m / s, thereby preventing erosion of the slurry system during the preheating process. CN204981766U discloses a device for preventing catalytic cracking slurry pump preheating wear, which keeps the standby pump in a standby state by optimizing the insulation of the pump and pipeline and injecting 350# heat transfer oil into the standby pump. The above existing technology can reduce the erosion of the slurry system, especially the preheating system, by optimizing the process flow and construction plan. However, it does not propose measures to safely isolate the slurry pump when internal leakage has occurred in the inlet and outlet valves and the preheating valve, so that the slurry pump can reach the maintenance condition.

[0005] Wuhan Petrochemical Plant investigated using a freezing method to prevent leakage from the outlet valve of a slurry pump and repair the mechanical seal [Refinery Equipment Design, Issue 5, 1983, Zhang Tingjian]. This involved ① removing the insulation from the pipelines above and below the slurry pump outlet valve and quenching the pipelines with cold water; ② installing a metal casing in the section of pipeline where the insulation had been removed, creating a 30-50 mm gap with the pipeline and filling the gap with crushed ice to further freeze the slurry in the pipeline; and ③ once the slurry in the pipeline was frozen, loosening the pump outlet flange and adding a blind plate. These three measures allowed the slurry pump, which had been unable to safely isolate the outlet valve from leaking, to safely undergo maintenance. This technical method is a temporary measure, and its effectiveness and safety cannot be guaranteed. Using this method on a slurry pump with a high probability of valve leakage and extremely serious consequences carries a high safety risk.

[0006] In summary, although the existing technology has made certain progress in preventing internal leakage of slurry pump-related valves and temporarily sealing internal leakage valves, when internal leakage occurs in the inlet and outlet valves of the slurry pump, there is still a technical problem that the spare slurry pump cannot be safely isolated from the system. Summary of the Invention

[0007] One of the purposes of the present invention is to provide a device for forced cooling and paraffin injection to seal the inlet and outlet pipelines of a catalytic slurry pump. When internal leakage occurs at the inlet and outlet valves of the slurry pump at the same time, the device can still reliably seal the inlet and outlet pipelines and safely isolate the slurry pump.

[0008] Through this device, paraffin is injected into the slurry pump quickly and quantitatively (liquid paraffin also enters the inlet and outlet pipelines through the inlet and outlet valves with internal leakage), and forced cooling measures are adopted for the inlet and outlet pipelines. The high solidification temperature of paraffin and the fact that its components will not contaminate the catalytic product are utilized to make the paraffin solidify quickly and cleanly achieve physical sealing of the internal leakage part, so that the slurry pump reaches the safe maintenance conditions.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A device for forced cooling and blocking the inlet and outlet pipelines of a catalytic slurry oil pump, comprising an oil slurry unit and:

[0011] A container filled with paraffin wax, used to place solid paraffin wax;

[0012] A heating mechanism, used for heating the container containing paraffin wax and melting the solid paraffin wax therein;

[0013] The cooling mechanism uses chilled water as the forced cooling medium to cool the relevant pipelines of the slurry unit;

[0014] The paraffin metering pump and delivery pipeline are used to deliver the melted paraffin to the oil slurry unit.

[0015] As a preferred embodiment of the present invention, the above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump, the relevant pipelines of the slurry unit are mainly the inlet and outlet pipelines of the slurry pump. By forced cooling the inlet and outlet pipelines of the above-mentioned slurry pump, the liquid paraffin therein is quickly converted into solid paraffin, thereby isolating the relevant slurry pump.

[0016] As another preferred embodiment of the present invention, the above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic oil slurry pump, the oil slurry unit includes a catalytic distillation tower and an oil slurry pump A and an oil slurry pump B located on both sides of the bottom of the above-mentioned catalytic distillation tower, one of the oil slurry pumps serving as a standby pump, the bottom of the above-mentioned catalytic distillation tower is connected to a main line, the end of the above-mentioned main line is divided into a first branch pipeline and a second branch pipeline, the above-mentioned oil slurry pump A is connected to the above-mentioned first branch pipeline, and the above-mentioned oil slurry pump B is connected to the above-mentioned second branch pipeline.

[0017] Furthermore, a distillation tower bottom electric valve is provided on the above-mentioned main line, an oil slurry pump A inlet valve and an oil slurry pump A inlet filter are provided on the above-mentioned first branch pipeline; an oil slurry pump B inlet valve and an oil slurry pump B inlet filter are provided on the above-mentioned second branch pipeline.

[0018] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump, the outlet pipeline of the above-mentioned slurry pump A is also provided with an outlet check valve of the slurry pump A and an outlet valve of the slurry pump A, and the above-mentioned slurry pump A is also connected to the outlet vent valve of the slurry pump A.

[0019] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump, the outlet pipeline of the above-mentioned slurry pump B is also provided with an slurry pump B outlet check valve and an slurry pump B outlet valve, and the above-mentioned slurry pump B is also connected to an slurry pump B outlet vent valve.

[0020] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump, the above-mentioned slurry pump A and slurry pump B are both connected to preheating valves, and the slurry pump A and slurry pump B are preheated through their respective preheating valves. At least four of the above-mentioned preheating valves are provided, of which at least three preheating valves are connected in series.

[0021] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump, the above-mentioned cooling mechanism includes a pipeline before the inlet valve of slurry pump A for cooling the inlet pipeline of slurry pump A, a pipeline after the outlet valve of slurry pump A for cooling the outlet pipeline of slurry pump A, a pipeline before the inlet valve of slurry pump B for cooling the inlet pipeline of slurry pump B, and a pipeline after the outlet valve of slurry pump B for cooling the outlet pipeline of slurry pump B.

[0022] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump has two pipelines in front of the inlet valve of the slurry pump A, one of which is provided with a chilled water inlet valve of the pipeline in front of the inlet valve of the slurry pump A, and the other is provided with a chilled water outlet valve of the pipeline in front of the inlet valve of the slurry pump A; the above-mentioned pipelines in front of the inlet valve of the slurry pump B are provided with two pipelines, one of which is provided with a chilled water inlet valve of the pipeline in front of the inlet valve of the slurry pump B, and the other is provided with a chilled water outlet valve of the pipeline in front of the inlet valve of the slurry pump B; two pipelines after the outlet valve of the slurry pump A are provided, one of which is provided with a chilled water inlet valve of the pipeline after the outlet valve of the slurry pump A, and the other is provided with a chilled water outlet valve of the pipeline after the outlet valve of the slurry pump A; two pipelines after the outlet valve of the slurry pump B are provided, one of which is provided with a chilled water inlet valve of the pipeline after the outlet valve of the slurry pump B, and the other is provided with a chilled water outlet valve of the pipeline after the outlet valve of the slurry pump B.

[0023] In the above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic oil slurry pump, the above-mentioned heating mechanism heats the outer wall of the container filled with paraffin, and the heating method adopts steam heating or electric heating.

[0024] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic oil slurry pump, the above-mentioned container filled with paraffin is a tank structure, a heating coil is provided on the outer wall of the above-mentioned tank structure, one end of the above-mentioned heating coil is connected to a temperature regulating valve, the above-mentioned heating mechanism is equipped with a temperature controller, the temperature of the container is monitored by the temperature controller, and then it is adjusted by the temperature regulating valve, the container filled with paraffin is heated and kept warm by the above-mentioned heating coil, and a steam trap is also connected to the heating coil at the end away from the above-mentioned temperature regulating valve.

[0025] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump has an outlet at the bottom of the container filled with paraffin, which is connected to the outlet vent valve of the slurry pump A and the outlet vent valve of the slurry pump B through corresponding pipelines.

[0026] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic oil slurry pump is equipped with a paraffin metering pump at the outlet position near the bottom of the container filled with paraffin, and liquid paraffin is injected into the oil slurry pump A / oil slurry pump B through the above-mentioned paraffin metering pump.

[0027] A second object of the present invention is to provide a method for forced cooling and blocking the inlet and outlet pipelines of a catalytic oil slurry pump, wherein a container containing paraffin is heated by a heating mechanism, and the paraffin therein is converted into liquid, and then the liquid paraffin is injected into the oil slurry unit, and the relevant pipelines of the oil slurry unit are forced to cool by a cooling mechanism, and the paraffin is waited for to solidify, and the physical blocking of the leakage part of the oil slurry unit is achieved by the solidification of the paraffin.

[0028] Specifically, the above method includes the following steps in sequence:

[0029] S1, the step of heating the container containing paraffin wax by a heating mechanism, and maintaining the temperature for a period of time after the paraffin wax is completely melted;

[0030] S2. Close the relevant inlet valve, outlet valve and preheating valve of the slurry pump, and keep the air valve at the outlet of the slurry pump connected to the outlet pipeline of the paraffin metering pump;

[0031] S3. Open the chilled water inlet valve and chilled water outlet valve on the inlet and outlet pipelines of the slurry pump and use chilled water to cool the pipelines;

[0032] S4. Start the paraffin metering pump to inject liquid paraffin into the slurry pump. After sufficient amount of paraffin is injected, stop the paraffin metering pump and close the slurry pump outlet vent valve.

[0033] S5. After confirming that the paraffin has completely solidified, remove the flanges of the relevant valves and install blind plates, then purge and replace the slurry pump. If qualified, hand it over for inspection and maintenance.

[0034] S6. After the maintenance is completed, remove the blind plate, restore the connection of the relevant inlet valve, outlet valve and preheating valve of the slurry pump, disconnect the connection between the slurry pump outlet vent valve and the paraffin metering pump, and use the slurry pump normally.

[0035] Furthermore, the criterion for judging internal leakage of the inlet and outlet valves is: after the inlet and outlet valves and the preheating valve are all closed, the temperature of the slurry pump body does not drop significantly, indicating that the high-temperature slurry is still flowing in the pump body.

[0036] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0037] Existing technologies use recycled oil without solid particles as a preheating medium or inject 350# thermal oil into a standby pump to achieve hot standby of the slurry pump, which can reduce erosion in the slurry system (including valves). If a valve leaks internally, temporary measures such as pouring water or applying ice are taken to cool the outlet pipeline to promote solidification of the slurry in the pipeline and seal it. In reality, since the solidification temperature of slurry is generally below 5°C, it is difficult to guarantee that these temporary measures will actually reduce the slurry in the pipeline to below the solidification temperature. If both the inlet and outlet valves of the slurry pump leak simultaneously, the temporary solution of freezing the slurry condensate is even less feasible.

[0038] The present invention adopts paraffin as the isolation medium, mainly based on two factors: (1) the solidification temperature of paraffin is relatively high, and the melting temperature is 47-64°C. (2) the main component of paraffin is C 18 ~C 30 The paraffin wax is a highly effective component of the oil, containing 80-95% straight-chain alkanes, a small amount of alkanes with individual branches, and monocyclic alkanes with long side chains. These components do not contaminate the product. Furthermore, the paraffin wax is similar to the components in the fractionator, preventing significant operational fluctuations. After the standby pump is overhauled, there is no need to replace the paraffin wax in the system. Simply commission the system's heat tracing line, which melts into a liquid and enters the bottom of the fractionator along with the oil slurry. This prevents system contamination and operational fluctuations.

[0039] The present invention cools the inlet and outlet pipelines through a cooling mechanism and adopts chilled water as a forced cooling medium. This is mainly because chilled water in refineries is relatively easy to obtain and has a temperature below 5°C, which has a good cooling effect.

[0040] When the inlet and outlet valves of the slurry pump leak internally at the same time, the present invention can still reliably seal the inlet and outlet pipelines to safely isolate the slurry pump. Paraffin is quickly and quantitatively injected into the slurry pump (liquid paraffin also enters the inlet and outlet pipelines through the inlet and outlet valves that leak internally), and forced cooling measures are put into place for the inlet and outlet pipelines. By utilizing the characteristics of paraffin's high solidification temperature and the fact that its components will not contaminate the catalytic product, the paraffin is quickly solidified, and the internal leakage part is cleanly physically sealed, thereby bringing the slurry pump into safe maintenance conditions.

[0041] In summary, the present invention adopts liquid paraffin to inject the slurry pump, the liquid paraffin gradually fills the pump body, and is filled into the outlet pipe section through the outlet valve, and is filled into the inlet pipe section through the inlet valve. After reaching the solidification temperature, it turns into solid paraffin, thereby physically sealing the leakage part of the slurry unit. The effectiveness and safety of the sealing method of the present invention can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be further described below with reference to the accompanying drawings:

[0043] Figure 1 This is a process flow chart of the present invention for forced cooling and paraffin injection to plug the inlet and outlet pipelines of the catalytic oil slurry pump;

[0044] In the picture:

[0045] 1. Catalytic distillation tower, 2. Electric valve at the bottom of distillation tower, 3. Inlet valve of slurry pump A, 4. Inlet filter of slurry pump A, 5. Inlet valve of slurry pump B, 6. Inlet filter of slurry pump B, 7. Slurry pump A, 8. Slurry pump B, 9. Outlet check valve of slurry pump A, 10. Outlet valve of slurry pump A, 11. Outlet check valve of slurry pump B, 12. Outlet valve of slurry pump B, 13. Outlet vent valve of slurry pump A, 14. Outlet vent valve of slurry pump B, 15-18. Preheating valve of slurry pump A, 19-22. Preheating valve of slurry pump B, 23. Paraffin heating tank, 24. Wax metering pump, 25. Temperature regulating valve, 26. Steam trap, 27. Heating coil, 28. Chilled water inlet valve of the pipeline behind the outlet valve of slurry pump A, 29. Chilled water outlet valve of the pipeline behind the outlet valve of slurry pump A, 30. Chilled water inlet valve of the pipeline behind the outlet valve of slurry pump B, 31. Chilled water outlet valve of the pipeline behind the outlet valve of slurry pump B, 32. Chilled water inlet valve of the pipeline before the inlet valve of slurry pump A, 33. Chilled water outlet valve of the pipeline before the inlet valve of slurry pump A, 34. Chilled water inlet valve of the pipeline before the inlet valve of slurry pump B, 35. Chilled water outlet valve of the pipeline before the inlet valve of slurry pump B. DETAILED DESCRIPTION

[0046] The present invention proposes a device and method for forced cooling and paraffin injection to seal the inlet and outlet pipelines of a catalytic oil slurry pump. In order to make the advantages and technical solutions of the present invention clearer and more specific, the present invention is described in detail below with reference to specific embodiments.

[0047] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “comprising” and the like will be understood to include stated elements or components but not to exclude other elements or components.

[0048] Throughout this document, for ease of description, spatially relative terms such as "below," "beneath," "below," "above," "above," etc. may be used to describe the relationship of one component or feature to another component or feature in the accompanying drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of the object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the drawings is turned over, the component described as being "below" or "below" other components or features will be oriented "above" the component or feature. Therefore, the exemplary term "below" can include both below and above. Components may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0049] The brand of paraffin wax mentioned in the present invention can be selected from 52#, 54#, 56#, 58#, etc., and the brand represents the melting point.

[0050] like Figure 1 As shown, the present invention provides a device for forced cooling and paraffin injection to seal the inlet and outlet pipelines of a catalytic oil slurry pump, comprising an oil slurry unit, a container filled with paraffin, a heating mechanism, a conveying pipeline and a cooling mechanism.

[0051] The slurry unit includes a catalytic fractionating tower 1 and slurry pumps A7 and B8 located on either side of the bottom of the tower. One slurry pump serves as a backup pump, while the other is in normal operation. A main pipeline is connected to the bottom of the catalytic fractionating tower. A motorized valve 2 is installed on the main pipeline, controlling the opening and closing of the pipeline. The end of the main pipeline is divided into a first branch pipeline and a second branch pipeline. Slurry pump A is connected to the first branch pipeline, and slurry pump B is connected to the second branch pipeline.

[0052] The above-mentioned first branch pipeline is provided with an oil slurry pump A inlet valve 3 and an oil slurry pump A inlet filter 4; the above-mentioned second branch pipeline is provided with an oil slurry pump B inlet valve 5 and an oil slurry pump B inlet filter 6; the outlet pipeline of the oil slurry pump A is also provided with an oil slurry pump A outlet check valve 9 and an oil slurry pump A outlet valve 10, and the above-mentioned oil slurry pump A is also connected to the oil slurry pump A outlet vent valve 13.

[0053] The outlet pipeline of the above-mentioned slurry pump B is also provided with an outlet check valve 11 of the slurry pump B and an outlet valve 12 of the slurry pump B. The above-mentioned slurry pump B is also connected to an outlet vent valve 14 of the slurry pump B.

[0054] The above-mentioned slurry pump A and slurry pump B are both connected to preheating valves, such as slurry pump A preheating valves 15-18 and slurry pump B preheating valves 19-22, through which slurry pump A and slurry pump B are preheated. There are four preheating valves, three of which are connected in series.

[0055] The above-mentioned heating mechanism heats the outer wall of the container filled with paraffin, and the heating method adopts steam heating or electric heating. If steam heating is used, a heating coil 27 can be set on the outer wall of the paraffin container, and one end of the heating coil is connected to a temperature regulating valve 25. The above-mentioned heating mechanism has its own temperature controller, which monitors the temperature of the container through a temperature monitor and then adjusts it through the temperature regulating valve. The container filled with paraffin is heated and kept warm by the above-mentioned heating coil. A steam trap 26 is also connected to the heating coil at one end away from the above-mentioned temperature regulating valve. The container filled with paraffin is preferably a tank structure, such as a paraffin heating tank 23. The container filled with paraffin is provided with an outlet at the bottom, and the outlet is connected to the outlet vent valve of the slurry pump A and the outlet vent valve of the slurry pump B through corresponding pipelines.

[0056] A paraffin metering pump 24 is provided at the outlet position near the bottom of the container filled with paraffin, and liquid paraffin is injected into the slurry pump A / slurry pump B through the paraffin metering pump 24 .

[0057] The above-mentioned cooling mechanism includes a pipeline before the inlet valve of slurry pump A for cooling the inlet pipeline of slurry pump A, a pipeline after the outlet valve of slurry pump A for cooling the outlet pipeline of slurry pump A, a pipeline before the inlet valve of slurry pump B for cooling the inlet pipeline of slurry pump B, and a pipeline after the outlet valve of slurry pump B for cooling the outlet pipeline of slurry pump B.

[0058] The above-mentioned device for forced cooling and blocking the inlet and outlet pipelines of the catalytic slurry pump is provided with two pipelines before the inlet valve of the slurry pump A, one of which is provided with a chilled water inlet valve 32 of the pipeline before the inlet valve of the slurry pump A, and the other is provided with a chilled water outlet valve 33 of the pipeline before the inlet valve of the slurry pump A; the above-mentioned pipelines before the inlet valve of the slurry pump B are provided with two pipelines, one of which is provided with a chilled water inlet valve 34 of the pipeline before the inlet valve of the slurry pump B, and the other is provided with a chilled water outlet valve 35 of the pipeline before the inlet valve of the slurry pump B; the pipelines after the outlet valve of the slurry pump A are provided with two pipelines, one of which is provided with a chilled water inlet valve 28 of the pipeline after the outlet valve of the slurry pump A, and the other is provided with a chilled water outlet valve 29 of the pipeline after the outlet valve of the slurry pump A; the pipelines after the outlet valve of the slurry pump B are provided with two pipelines, one of which is provided with a chilled water inlet valve 30 of the pipeline after the outlet valve of the slurry pump B, and the other is provided with a chilled water outlet valve 31 of the pipeline after the outlet valve of the slurry pump B.

[0059] The present invention will be further described below with reference to specific embodiments.

[0060] Example 1:

[0061] The operating temperature at the bottom of the distillation tower is as high as 320℃. If the inlet and outlet valves of the standby slurry pump leak simultaneously, the standby slurry pump cannot be safely isolated from the system for maintenance. The standard for judging the inlet and outlet valve internal leakage is: after the inlet and outlet valves and preheating valve are all closed, the pump body temperature does not drop significantly, indicating that the high-temperature slurry is still flowing in the pump body. Follow the steps below to seal and isolate:

[0062] (1) Add solid paraffin into the paraffin heating tank 23, open the temperature regulating valve 25, slowly heat the paraffin solid to melt it, and when the temperature rises to the paraffin melting temperature, maintain the temperature for more than 1 hour through the temperature control circuit to ensure that all the paraffin in the tank is melted.

[0063] (2) Close the steam heating pipes of the inlet and outlet pipelines and preheating pipeline of the slurry pump A.

[0064] (3) Close the inlet valve, outlet valve and preheating valve of slurry pump A注① .

[0065] (4) Connect the outlet vent valve of the slurry pump A to the outlet pipeline of the paraffin metering pump, and open the outlet vent valve 13 of the standby slurry pump A.

[0066] (5) Open the chilled water inlet valve 28 of the pipeline behind the outlet valve of the slurry pump A, the chilled water outlet valve 29 of the pipeline behind the outlet valve of the slurry pump A, the chilled water inlet valve 32 of the pipeline before the inlet valve of the slurry pump A, and the chilled water outlet valve 33 of the pipeline before the inlet valve of the slurry pump A, and use chilled water to cool the pipeline.

[0067] (6) Start the paraffin metering pump 24 注② Inject liquid paraffin into the standby pump in sufficient quantity. 注③ Afterwards, stop the paraffin metering pump 24 and close the outlet vent valve 13 of the slurry pump A.

[0068] (7) Make sure the paraffin has completely solidified 注④ After that, disassemble the valve flange (after disassembling the inlet valve of slurry pump A, before disassembling the outlet valve of slurry pump A, and after disassembling the preheating valve 18 of slurry pump A) and install the blind plate, then purge and replace the slurry pump. After passing the inspection, it will be handed over for maintenance.

[0069] (8) After the overhaul is completed, the blind plate is removed, the inlet and outlet of the slurry pump A, the preheating pipeline, etc. are restored to connection, and the connection between the outlet vent valve 13 of the slurry pump A and the paraffin metering pump 24 is disconnected.

[0070] (10) Slurry pump A enters the standby step.

[0071] Note ①: After all valves are closed, the injected liquid paraffin will enter the connected pipes through the internally leaking valve. To determine which valve is leaking, you can analyze the surface temperature changes of the pipes connected to the valves. For example, after the standby slurry pump outlet valve is injected with liquid paraffin, if the surface temperature of the outlet pipe drops significantly after being measured by an infrared thermometer, it can be determined that the outlet valve is leaking internally. If the surface temperature of the inlet pipe and preheating pipe remains unchanged, it can be determined that the inlet valve and preheating valve are not leaking internally.

[0072] Note ②: The maximum flow rate of the paraffin metering pump should be no less than (3 times / hour of the total volume from the inlet valve to the outlet valve of the slurry pump) to ensure that paraffin can be quickly injected into the system to prevent paraffin from solidifying in the injection line and other parts.

[0073] Note ③: The injection amount of liquid paraffin should be no less than 3 times the total volume from the inlet valve to the outlet valve of the slurry pump, and the injection amount is calculated using a metering pump.

[0074] Note ④: The criterion for judging whether the paraffin is completely solidified is that the pump body temperature does not rise after the system operating conditions remain unchanged and forced cooling is stopped for 1 hour.

[0075] Example 2:

[0076] The above device is used to block the inlet and outlet pipelines of the catalytic oil slurry pump. The specific method is as follows:

[0077] The first step is to heat the container containing paraffin wax by a heating mechanism, and after the paraffin wax is completely melted, maintain the temperature for a period of time;

[0078] Step 2: Close the relevant inlet valve, outlet valve and preheating valve of the slurry pump, and keep the outlet valve of the slurry pump connected to the outlet pipeline of the paraffin metering pump;

[0079] Step 3: Open the chilled water inlet valve and chilled water outlet valve on the inlet and outlet pipelines of the slurry pump and use chilled water to cool the pipelines;

[0080] Step 4: Start the paraffin metering pump to inject liquid paraffin into the slurry pump. After sufficient amount of paraffin is injected, stop the paraffin metering pump and close the slurry pump outlet vent valve.

[0081] Step 5: After confirming that the paraffin has completely solidified, remove the flanges of the relevant valves and install blind plates, then purge and replace the slurry pump, and hand it over for inspection and maintenance if it is qualified;

[0082] Step 6. After the maintenance is completed, remove the blind plate, restore the connection of the relevant inlet valve, outlet valve and preheating valve of the slurry pump, disconnect the connection between the slurry pump outlet vent valve and the paraffin metering pump 24, and use the slurry pump normally.

[0083] Example 3:

[0084] Slurry pump B at the bottom of a catalytic distillation tower was operating normally, while slurry pump A required maintenance. During the pump removal process, it was discovered that even with slurry pump A's inlet valve 3, outlet valve 10, and preheating valves 15-18 closed, the pump's body temperature had not significantly decreased. This indicated internal leakage at both the inlet and outlet valves. The operating temperature at the bottom of the distillation tower was 332°C, and the solidification temperature of the slurry was approximately 5°C.

[0085] The following takes the example of internal leakage of the inlet valve 3, outlet valve 10 and outlet check valve 9 of the slurry pump A when the slurry pump A is cut out for maintenance to further illustrate the overall blocking and isolation and operation steps.

[0086] (1) Add solid paraffin wax to the paraffin heating tank 23 of the invention, open the paraffin tank temperature regulating valve 25, slowly heat the paraffin solid to melt it, and when the temperature rises to the melting point (the brand of paraffin is the melting point), maintain the temperature for more than 1 hour through the temperature control circuit to ensure that all the paraffin in the tank is melted.

[0087] (2) Close the steam heating pipes of the inlet and outlet pipelines of slurry pump A and the preheating pipeline.

[0088] (3) Close the inlet valve of slurry pump A, the outlet valve of slurry pump A and the preheating valves 15-18 of slurry pump A.

[0089] (4) Connect the outlet vent valve 13 of the slurry pump A to the outlet pipeline of the paraffin metering pump 24, open the outlet vent valve 13 of the slurry pump A, and put the inlet and outlet pipelines of the paraffin metering pump 24 into heating.

[0090] (5) Start the paraffin metering pump 24 to inject liquid paraffin into the slurry pump A. The injection amount of liquid paraffin should be no less than 3 times the total volume from the inlet valve to the outlet of the slurry pump A. The injection amount is measured by the paraffin metering pump 24.

[0091] (6) First, open the chilled water inlet valve 32 and the chilled water outlet valve 33 of the pipeline in front of the inlet valve of slurry pump A. Due to the low pump inlet pressure, the injected liquid paraffin will first enter the pump inlet pipeline through the internally leaking pump inlet valve. Under the forced cooling effect, the inlet paraffin solidifies. At this time, the injected liquid paraffin will then enter the outlet pipeline of slurry pump A through the internally leaking outlet valve 10 of slurry pump A.

[0092] (7) Open the chilled water inlet valve 28 and the chilled water inlet valve 29 of the pipeline behind the outlet valve of the slurry pump A. The liquid paraffin entering the pump outlet pipeline will solidify under the effect of forced cooling. Note that the outlet pressure of the paraffin metering pump cannot exceed 3MPa.

[0093] (8) Stop the paraffin metering pump 24 and close the outlet vent valve 13 of the slurry pump A.

[0094] (9) Keep the system working condition unchanged. After stopping the forced cooling for 1 hour, if the temperature of the slurry pump A pump body does not rise, it is judged that the paraffin in the pump body has completely solidified. After confirming that the paraffin is completely solidified, disassemble the valve flange (after disassembling the inlet valve 3 of the slurry pump A, before disassembling the outlet valve 10 of the slurry pump A, and after disassembling the preheating valve 18 of the slurry pump A) and install the blind plate to complete the physical blocking of the system. Perform the slurry pump purge and replacement. After passing the inspection and maintenance work.

[0095] (10) After the maintenance is completed, remove the blind plate installed above, remove the forced cooling copper pipe, restore the connection of the inlet and outlet of the slurry pump A, the preheating pipeline, etc., restore the insulation, and disconnect the connection between the outlet vent valve 13 of the slurry pump A and the paraffin metering pump 24.

[0096] (11) Put seal oil (light diesel component) into slurry pump A until the pump body pressure no longer rises, and test the slurry pump seal leakage; if the inspection shows no abnormality, put mechanical seal cooling steam into use.

[0097] (12) Put the slurry pump A pipeline into operation with heating. The solidified paraffin wax in the inlet and outlet pipelines gradually melts due to the heat and mixes with the slurry oil to become part of the process medium. Open the inlet valve 3 of the slurry pump A and the outlet vent valve 13 of the slurry pump A (connected to a closed discharge). The slurry oil enters the pump body to replace the leak test seal oil and fill the pump. The slurry pump A reaches the standby state. Note: The preheating temperature is required to be no more than 50℃ / h.

[0098] The preferred embodiments of the present invention are described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto.

[0099] Although terms such as slurry pump A, slurry pump B, slurry pump A outlet valve, slurry pump B outlet check valve, heating coil, etc. are used more frequently in this document, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

[0100] It should be further noted that the specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A method for forced cooling and blocking the inlet and outlet pipelines of a catalytic oil slurry pump, characterized by: The process involves heating a container filled with paraffin wax and converting the wax into liquid. The liquid paraffin is then injected into the slurry oil unit. The cooling mechanism is used to forcefully cool the relevant pipelines of the slurry oil unit, and the paraffin wax solidifies. This allows the leakage in the slurry oil unit to be physically blocked. The invention adopts a device for forced cooling and blocking the inlet and outlet pipelines of a catalytic oil slurry pump, the device for forced cooling and blocking the inlet and outlet pipelines of a catalytic oil slurry pump comprises an oil slurry unit and further comprises: A container filled with paraffin wax, used to place solid paraffin wax; A heating mechanism, used for heating the container containing paraffin wax and melting the solid paraffin wax therein; The cooling mechanism uses chilled water as the forced cooling medium to cool the relevant pipelines of the slurry unit; A paraffin metering pump and a delivery pipeline are used to deliver the melted paraffin to the oil slurry unit in a quantitative manner; The relevant pipelines of the slurry unit are the inlet and outlet pipelines of the slurry pump. By forcibly cooling the inlet and outlet pipelines of the slurry pump, the liquid paraffin therein is quickly converted into solid paraffin, thereby isolating the relevant slurry pump; The slurry unit includes a catalytic distillation tower and a slurry pump A and a slurry pump B located on both sides of the bottom of the catalytic distillation tower, one of which serves as a backup pump. The bottom of the catalytic distillation tower is connected to a main line, the end of which is divided into a first branch line and a second branch line. The slurry pump A is connected to the first branch line, and the slurry pump B is connected to the second branch line. A fractionation tower bottom electric valve is provided on the main pipeline, an oil slurry pump A inlet valve and an oil slurry pump A inlet filter are provided on the first branch pipeline; an oil slurry pump B inlet valve and an oil slurry pump B inlet filter are provided on the second branch pipeline; The outlet pipeline of the slurry pump A is also provided with an outlet check valve of the slurry pump A and an outlet valve of the slurry pump A. The slurry pump A is also connected to an outlet vent valve of the slurry pump A; The outlet pipeline of the slurry pump B is also provided with an outlet check valve of the slurry pump B and an outlet valve of the slurry pump B. The slurry pump B is also connected to an outlet vent valve of the slurry pump B; The slurry pump A and the slurry pump B are both connected to a preheating valve, and the slurry pump A and the slurry pump B are preheated through their respective preheating valves. There are at least four preheating valves, of which at least three are connected in series. The cooling mechanism includes a pipeline before the inlet valve of slurry pump A for cooling the inlet pipeline of slurry pump A, a pipeline after the outlet valve of slurry pump A for cooling the outlet pipeline of slurry pump A, a pipeline before the inlet valve of slurry pump B for cooling the inlet pipeline of slurry pump B, and a pipeline after the outlet valve of slurry pump B for cooling the outlet pipeline of slurry pump B; There are two pipelines in front of the inlet valve of the slurry pump A, one of which is provided with a chilled water inlet valve of the pipeline in front of the inlet valve of the slurry pump A, and the other is provided with a chilled water outlet valve of the pipeline in front of the inlet valve of the slurry pump A; there are two pipelines in front of the inlet valve of the slurry pump B, one of which is provided with a chilled water inlet valve of the pipeline in front of the inlet valve of the slurry pump B, and the other is provided with a chilled water outlet valve of the pipeline in front of the inlet valve of the slurry pump B; there are two pipelines after the outlet valve of the slurry pump A, one of which is provided with a chilled water inlet valve of the pipeline behind the outlet valve of the slurry pump A, and the other is provided with a chilled water outlet valve of the pipeline behind the outlet valve of the slurry pump A; there are two pipelines after the outlet valve of the slurry pump B, one of which is provided with a chilled water inlet valve of the pipeline behind the outlet valve of the slurry pump B, and the other is provided with a chilled water outlet valve of the pipeline behind the outlet valve of the slurry pump B; The heating mechanism heats the outer wall of the container filled with paraffin wax, and the heating method adopts steam heating or electric heating; The container containing paraffin wax is a tank structure, and a heating coil is provided on the outer wall of the tank structure. One end of the heating coil is connected to a temperature regulating valve. The heating mechanism is equipped with a temperature controller, which monitors the temperature of the container and then adjusts it through the temperature regulating valve. The heating coil heats and keeps the container containing paraffin wax warm. A steam trap is also connected to the heating coil at the end away from the temperature regulating valve. The container filled with paraffin wax is provided with an outlet at the bottom, which is connected to the outlet vent valve of slurry pump A and the outlet vent valve of slurry pump B through corresponding pipelines; The paraffin metering pump is arranged at the outlet position near the bottom of the container filled with paraffin, and liquid paraffin is injected into the slurry pump A or the slurry pump B through the paraffin metering pump; The method for forced cooling and blocking the inlet and outlet pipelines of the catalytic oil slurry pump comprises the following steps in sequence: S1, the step of heating the container containing paraffin wax by a heating mechanism, and maintaining the temperature for a period of time after the paraffin wax is completely melted; S2. Close the relevant inlet valve, outlet valve and preheating valve of the slurry pump, and keep the air valve at the outlet of the slurry pump connected to the outlet pipeline of the paraffin metering pump; S3. Open the chilled water inlet valve and chilled water outlet valve on the inlet and outlet pipelines of the slurry pump and use chilled water to cool the pipelines; S4. Start the paraffin metering pump to inject liquid paraffin into the slurry pump. After sufficient amount of paraffin is injected, stop the paraffin metering pump and close the slurry pump outlet vent valve. S5. After confirming that the paraffin has completely solidified, remove the flanges of the relevant valves and install blind plates, then purge and replace the slurry pump. If qualified, hand it over for inspection and maintenance. S6. After the overhaul is completed, remove the blind plate, reconnect the relevant inlet valve, outlet valve and preheating valve of the slurry pump, disconnect the outlet vent valve of the slurry pump from the paraffin metering pump, and use the slurry pump normally; The criteria for judging internal leakage of inlet and outlet valves are: after the inlet and outlet valves and preheating valves are all closed, the temperature of the slurry pump body does not drop significantly, indicating that the high-temperature slurry is still flowing in the pump body; In step S4, the maximum flow rate of the paraffin metering pump is not less than 3 times the total volume from the inlet valve to the outlet valve of the slurry pump per hour, and the injection amount of liquid paraffin is not less than 3 times the total volume from the inlet valve to the outlet valve of the slurry pump, and the injection amount is calculated by the paraffin metering pump; The criterion for judging whether the paraffin wax is completely solidified in step S5 is that the temperature of the pump body does not rise after the system operating conditions are kept unchanged and forced cooling is stopped for 1 hour.

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