Self-cleaning device applied to polyolefin temperature sleeve

Abstract

The utility model discloses a self-cleaning device applied to a polyolefin temperature sleeve, which comprises a single-action pneumatic actuator, the outer surface of the single-action pneumatic actuator is fixedly connected with a housing through a bolt, the outer surface of the housing is fixedly connected with a valve body through a bolt, the output end of the single-action pneumatic actuator is fixedly connected with the sleeve, and the output end of the single-action pneumatic actuator is fixedly connected with the valve body. The sleeve is installed in the valve body, the scraper is installed in the valve body and located on the outer side of the sleeve, the positioning sleeve is installed on the outer surface of the sleeve, the plunger valve element is arranged between the sleeve and the valve body, the lower padding is filled in the padding portion of the valve body, the padding spacer bush is arranged on the outer side of the lower padding, and the upper padding is arranged on the outer side of the padding spacer bush. The outer side of the upper filler is provided with a filler pressing sleeve, the outer side of the filler pressing sleeve is provided with a filler pressing plate, the inner wall of the filler pressing plate is in threaded connection with a stud, and the temperature sleeve is automatically cleaned, so that polymers adhered to the temperature sleeve can be removed, and the temperature in the reactor can be accurately measured.

Description

Technical Field

[0001] The utility model relates to the technical field of alpha-olefin preparation, in particular to a self-cleaning device for polyolefin temperature sleeves. Background Art

[0002] The ethylene oligomerization reaction mechanism is complex, characterized by significant hysteresis, high inertia, and nonlinearity. Temperature measurement and control within the reactor are crucial factors affecting product quality and ensuring reactor safety. The reactor's temperature measurement element plays a crucial role in both controlling the reactor's temperature and ensuring the system's highest-level emergency shutdown. As solvent, ethylene, H2, and catalyst are added to the reactor, an exothermic reaction between the ethylene and catalyst, driven by the agitator, gradually begins as the reaction time increases. Conventional reactor temperature measurement involves inserting a temperature measuring element within a temperature well. As the reaction time increases, the thermowell gradually becomes clogged with reactants. As the reaction time gets longer, the amount of clogged reactants increases. When the thermowell becomes clogged with reactants, the actual temperature inside the reactor cannot be measured effectively and in a timely manner, resulting in an uncontrolled temperature inside the reactor. The clogged thermowell can cause a significant lag in temperature measurement. The actual temperature inside the reactor may have reached the interlock temperature that triggers an emergency stop, but the measured temperature may be far below this interlock temperature. This can lead to misjudgment by process operators, resulting in the emergency stop interlock not being triggered when it should have, seriously impacting plant safety. If the clogged polymer contains a catalyst, a vigorous polymerization reaction can occur at the thermowell, causing the temperature to rise sharply, triggering the emergency stop system and causing an unnecessary shutdown. Utility Model Content

[0003] The purpose of the utility model is to solve at least one of the technical problems existing in the prior art and to provide a self-cleaning device for a polyolefin temperature sleeve. By automatically cleaning the temperature sleeve, the polymer stuck on the temperature sleeve can be removed and the temperature in the reactor can be accurately measured.

[0004] The utility model also provides the above-mentioned self-cleaning device for polyolefin temperature sleeve, comprising: a single-acting pneumatic actuator, the outer surface of the single-acting pneumatic actuator is fixedly connected to a cover by bolts, the outer surface of the cover is fixedly connected to a valve body by bolts, the output end of the single-acting pneumatic actuator is fixedly connected to a sleeve, the sleeve is installed inside the valve body, a scraper is installed inside the valve body, the scraper is located on the outside of the sleeve, a positioning sleeve is installed on the outer surface of the sleeve, a plunger valve core is arranged between the sleeve and the valve body, a packing portion of the valve body is filled with a lower packing, a packing spacer is arranged on the outside of the lower packing, an upper packing is arranged on the outside of the packing spacer, a packing gland is arranged on the outside of the upper packing, a packing pressure plate is arranged on the outside of the packing pressure plate, a stud is threadedly connected to the inner wall of the packing pressure plate, a hexagonal nut is threadedly connected to the outer surface of the stud, a disc spring is arranged between the hexagonal nut and the packing pressure plate, and a PT100 thermometer is installed at one end of the sleeve.

[0005] According to the self-cleaning device for polyolefin temperature sleeves described in the utility model, the positioning sleeve is made of PPL material, and the positioning sleeve is located inside the valve body. The positioning sleeve made of PPL material is used to support the stability of the sleeve, reduce vibration, and enhance the stability of the sleeve.

[0006] According to the utility model, a self-cleaning device for polyolefin temperature sleeves is provided with a few gaps between the scraper and the sleeve, the surface of the scraper is nitrided as a whole, and the scraper material is 17-4PH. The surface is nitrided as a whole to ensure the hardness of the scraper, and the scraper edge is sharp for easy scraping. There are a few gaps between the inner diameter of the scraper and the sleeve, firstly to ensure that sticky materials on the sleeve can be scraped clean, and secondly, due to the high temperature of the reactor, the sleeve and the scraper have a certain thermal expansion, and a little gap is left to prevent the scraper and the sleeve from locking due to heat.

[0007] According to the utility model, a self-cleaning device for a temperature sleeve for polyolefins is provided. The sleeve has a telescopic length of 150 mm. Two limit switches are provided on the outer surface of the single-acting pneumatic actuator, and the two limit switch signals are introduced into the DCS system. The telescopic length of the sleeve is 150 mm, ensuring that the temperature probe can penetrate into the reactor and accurately measure the temperature. The packing is installed at the bottom of the valve seat. After the sleeve is completely withdrawn by 150 mm, the extended part cannot contact the packing, thereby preventing the unscraped material from damaging the packing and causing leakage. The two limit switches are provided to monitor whether the material sticking to the temperature sleeve has been scraped clean. At the same time, the two limit switch signals are introduced into the DCS system to serve as the conditions for starting the cylinder.

[0008] According to the self-cleaning device for polyolefin temperature sleeves described in the utility model, the material of the lower filler is flexible graphite, the material of the upper filler is RPTFE, and the lower sealing material is a flexible graphite ring, which also plays a certain dust-proof role.

[0009] According to the self-cleaning device for polyolefin temperature sleeves described in the utility model, the valve body, plunger valve core, packing spacer, packing gland and packing pressure plate are all made of 316 stainless steel, and the disc spring, stud bolt and hexagonal nut are all made of 304 stainless steel. 316 stainless steel is more corrosion-resistant than other materials and is suitable for use in harsh environments. The use of 304 stainless steel improves the mechanical strength and stability of the equipment and ensures the robustness of the overall structure.

[0010] Beneficial effects

[0011] 1. Compared with the prior art, the self-cleaning device for polyolefin temperature sleeves can remove polymers stuck on the temperature sleeves by automatically cleaning the temperature sleeves.

[0012] 2. Compared with the existing technology, this device is applied to the polyolefin temperature sleeve self-cleaning device and accurately measures the temperature inside the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention is further described below with reference to the accompanying drawings and embodiments:

[0014] Figure 1 This is an overall structural diagram of a self-cleaning device for polyolefin temperature sleeves according to the present invention.

[0015] Legend:

[0016] 1. Scraper; 2. Locating sleeve; 3. Valve body; 4. Plunger valve core; 5. Lower packing; 6. Packing spacer; 7. Upper packing; 8. Packing gland; 9. Packing pressure plate; 10. Disc spring; 11. Stud bolt; 12. Hexagonal nut; 13. PT100 thermometer; 14. Single-acting pneumatic actuator. DETAILED DESCRIPTION

[0017] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0018] Reference Figure 1The embodiment of the utility model is a self-cleaning device for polyolefin temperature sleeves, which includes: a single-acting pneumatic actuator 14, which drives the sleeve to move up and down, adopts a double-acting piston action, has a large thrust, and the minimum thrust of the cylinder opening is 15000N, which ensures that the sleeve can operate normally after sticking to the material. The sleeve is made of a dual-phase steel with a diameter of 20mm and a hole of 7-8mm. The top of the hole is left with 5-10mm to ensure the strength after the hole is turned, and at the same time, the temperature is transferred in time. The outer surface of the single-acting pneumatic actuator 14 is through The cover is fixedly connected with the cover by bolts, and the outer surface of the cover is fixedly connected with the valve body 3 by bolts. As the main structure of the whole device, it carries other components. The length of the valve body 3 is 210mm, which is determined by the wall thickness of the reactor and the length of the boss. The diameter of the cylindrical valve is 38mm. The interval between the valve body 3 and the reactor is minimized to avoid material accumulation in the valve body 3. The output end of the single-acting pneumatic actuator 14 is fixedly connected with a sleeve, which is installed inside the valve body 3. A scraper 1 is installed inside the valve body 3 to scrape off the sticky matter on the sleeve. Scraper 1 is in the On the outside of the sleeve, a positioning sleeve 2 is installed on the outer surface of the sleeve to support the stability of the sleeve and reduce vibration. A plunger valve core 4 is provided between the sleeve and the valve body 3, with a stroke of 150mm to limit the movement of the sleeve and prevent it from extending too long. The packing part of the valve body 3 is filled with a lower packing 5, which plays a certain dust-proof role. A packing spacer 6 is provided on the outside of the lower packing 5 to store grease. An upper packing 7 is provided on the outside of the packing spacer 6 to further enhance the sealing effect. A packing pressing sleeve 8 is provided on the outside of the upper packing 7 to apply pressure to the packing. A packing pressure plate 9 is provided on the outside of the sleeve 8, which cooperates with the stud bolts 11 to adjust the tightness of the packing. The inner wall of the packing pressure plate 9 is threadedly connected with the stud bolts 11, which cooperate with the packing pressure plate 9 to adjust the tightness of the packing. The outer surface of the stud bolt 11 is threadedly connected with a hexagonal nut 12, which is used in conjunction with the stud bolt 11 to lock the packing pressure plate 9. A disc spring 10 is provided between the hexagonal nut 12 and the packing pressure plate 9 to reduce the continuous tightening requirement of the packing during use. A PT100 thermometer 13 is installed at one end of the sleeve for accurately measuring the temperature.

[0019] The material of the locating sleeve 2 is PPL. The locating sleeve 2 is located inside the valve body 3. There is a few gaps between the scraper 1 and the pipe sleeve. The surface of the scraper 1 is nitrided as a whole. The telescopic length of the sleeve is 150mm. Two limit switches are provided on the outer surface of the single-acting pneumatic actuator 14, and the two limit switch signals are introduced into the DCS system. The material of the lower packing 5 is flexible graphite, and the material of the upper packing 7 is RPTFE. The valve body 3, plunger valve core 4, packing spacer 6, packing sleeve 8 and packing pressure plate 9 are all made of 316 stainless steel, and the material of the disc spring 10, stud bolt 11 and hexagonal nut 12 are all 304 stainless steel.

[0020] Working principle: The single-acting pneumatic actuator 14 drives the sleeve to move up and down, and the scraper 1 can scrape the sticky materials on the surface of the sleeve, playing a self-cleaning function. Its working temperature is ≤200℃. It can be cleaned manually, regularly, or automatically. Manual cleaning: The reactor is equipped with three temperature detection instruments, all installed on the same plane. When the process personnel find that the temperature difference between the three temperature measuring points of the reactor is large, they can manually click on the opening and closing of the temperature sleeve device on the DCS screen to clean the sticky materials of the temperature sleeve. When the display values ​​of the three temperature measuring points of the reactor are consistent, it means that the sticky materials of the temperature sleeve are cleaned up. Regular cleaning: Through the DCS system configuration, according to the experience of the workers The technician can set the temperature sleeve cleaning timer on the DCS screen. For example, if cleaning is required every two hours, the technician enters 2. The DCS system configuration module then begins counting. When the timer reaches two hours, the RS trigger activates, energizing the temperature sleeve cylinder solenoid valve. Once energized, the sleeve withdraws, and scraper 1, mounted on top of valve body 3, scrapes the material stuck to the sleeve. After detecting the withdrawal position switch signal for 2 seconds, the temperature sleeve cylinder solenoid valve de-energizes, and the sleeve extends into the reactor. After detecting the position switch signal for 2 seconds, the temperature sleeve cylinder solenoid valve energizes and withdraws again. This back-and-forth cycle thoroughly cleans the material stuck to the sleeve. After the temperature sleeve cylinder completes its operation, the timer reset function is triggered, restarting the countdown. This cycle repeats, ensuring accurate measurement of the temperature sensing element. If the reactor is in the parking state, the parking signal is introduced into the function block and the timed cleaning function block is cut off. This can extend the service life of the temperature sleeve self-cleaning device and save energy. Automatic cleaning: The reactor is equipped with three temperature detection instruments, all installed on the same plane and all introduced into the DCS system. By configuring the three temperature detection instruments in the DCS system, the three temperature instruments compare the temperatures of each two, such as A and B, A and C, and B and C. When the same temperature measurement point has two temperature deviations greater than or equal to plus or minus 2°C in the deviation function block, the trigger triggers the function block to automatically activate the temperature sleeve self-cleaning device. The number of actions and methods are the same as the timed cleaning, so as to automatically clean the material stuck to the temperature sleeve. By analogy, it is ensured that the three temperature detection elements can accurately measure the temperature in the reactor.

[0021] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A self-cleaning device for polyolefin temperature sleeve, characterized in that: include: A single-acting pneumatic actuator (14), wherein the outer surface of the single-acting pneumatic actuator (14) is fixedly connected to a cover by bolts, the outer surface of the cover is fixedly connected to a valve body (3) by bolts, the output end of the single-acting pneumatic actuator (14) is fixedly connected to a sleeve, the sleeve is installed inside the valve body (3), a scraper (1) is installed inside the valve body (3), the scraper (1) is located outside the sleeve, a positioning sleeve (2) is installed on the outer surface of the sleeve, a plunger valve core (4) is provided between the sleeve and the valve body (3), and the packing part of the valve body (3) is filled with a lower filler. The outer side of the lower packing (5) is provided with a packing spacer (6), the outer side of the packing spacer (6) is provided with an upper packing (7), the outer side of the upper packing (7) is provided with a packing pressing sleeve (8), the outer side of the packing pressing sleeve (8) is provided with a packing pressure plate (9), the inner wall of the packing pressure plate (9) is threadedly connected with a stud bolt (11), the outer surface of the stud bolt (11) is threadedly connected with a hexagonal nut (12), a disc spring (10) is provided between the hexagonal nut (12) and the packing pressure plate (9), and a PT100 thermometer (13) is installed at one end of the sleeve.

2. The self-cleaning device for polyolefin temperature sleeve according to claim 1, characterized in that: The material of the positioning sleeve (2) is PPL material, and the positioning sleeve (2) is located inside the valve body (3).

3. The self-cleaning device for polyolefin temperature sleeve according to claim 1, characterized in that: A few gaps are left between the scraper (1) and the tube sleeve, and the entire surface of the scraper (1) is nitrided.

4. The self-cleaning device for polyolefin temperature sleeve according to claim 1, characterized in that: The telescopic length of the sleeve is 150 mm. Two limit switches are provided on the outer surface of the single-acting pneumatic actuator (14), and the signals of the two limit switches are introduced into the DCS system.

5. The self-cleaning device for polyolefin temperature sleeve according to claim 1, characterized in that: The material of the lower filler (5) is flexible graphite, and the material of the upper filler (7) is RPTFE.

6. The self-cleaning device for polyolefin temperature sleeve according to claim 1, characterized in that: The valve body (3), the plunger valve core (4), the packing spacer (6), the packing pressure sleeve (8) and the packing pressure plate (9) are all made of 316 stainless steel, and the disc spring (10), the stud bolt (11) and the hexagonal nut (12) are all made of 304 stainless steel.

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