Cleaning method for natural gas-to-ethylene glycol reactor sheet

Abstract

The invention discloses a cleaning method for a natural gas-to-ethylene glycol reactor sheet, which comprises the following cleaning steps: S1, high-pressure flushing: performing high-pressure flushing on each module in a reactor through a high-pressure water pipe, flushing a catalyst easy to fall off in each module, and discharging the catalyst from a water outlet at the bottom of the reactor; s2, circulating chemical cleaning: before cleaning, firstly laying a cleaning pipeline above a sheet bar of each module, and then spraying chemical liquid to the sheet bar and the inner wall of each module through the laid cleaning pipeline by a circulating cleaning device for chemical soaking and cleaning, s2, washing and softening the bonded catalyst which is not cleaned by high-pressure washing in the step S1 through circulating chemical liquid, so that the catalyst is softened and falls off; and S3, high-pressure cleaning: after the cyclic chemical cleaning is completed, performing high-pressure cleaning on the catalyst attached to the plate sheet through the high-pressure water pipe again, and cleaning the softened and falling catalyst through the high-pressure cleaning.

Description

Technical Field

[0001] The present invention relates to the technical field of cleaning methods for reactor plates in the production of ethylene glycol from natural gas, and specifically relates to a cleaning method for reactor plates in the production of ethylene glycol from natural gas. Background Art

[0002] Currently, in reactors for producing ethylene glycol from natural gas, most are split-tube reactors, and the plate reactor is the first of its kind in China in our company. Among them, the vertical height of the plate reactor is 16620 mm, the diameter is 6200 mm, the heat exchange area of the reactor cylinder is 5666 m 2 and the volume is 369 m 3 . The materials of the cylinder and the head are: Q345R + S30403. The design pressure of the reactor internals is 4.0 MPaG, the design temperature is 252 °C, and the working medium is boiler feed water / steam. The reactor internals are composed of 8 identical large modules and 8 identical small modules. The specifications of each large module are 1066 (width) * 2122 (length) * 4930 (height) mm, and the specifications of each small module are 1066 (width) * 679 (length) * 4930 (height) mm.

[0003] After long-term use, catalyst coke deposits will form on the plates, as shown in Figure 2 and Figure 3 . Our company used the traditional high-pressure cleaning method to clean the first reactor for producing ethylene glycol from natural gas. During the cleaning process, when using high-pressure cleaning for the first time, the pressure was 600 MPa and the coked part could not be cleaned. The pressure was gradually increased to 1000 MPa, and the coke deposits still adhered to the plates, as shown in Figure 4 . Therefore, in order to thoroughly clean the coke deposits adhering to the plates, it was finally necessary to adopt the method of manually entering the reactor and using special tools to clean the coke deposits on the plates, which took 12 days to clean one reactor as a whole. Moreover, the water resources used during the cleaning process could not be counted, and the washed coke deposits were difficult to concentrate and neutralize, resulting in greater cleaning difficulty, time, energy consumption, and environmental protection compared to tube bundle reactors. There were also extremely difficult problems in cleaning the coked parts of the plates. If the plates were not cleaned thoroughly, it would affect the catalyst life and production efficiency, etc. Therefore, the traditional cleaning method no longer meets the existing equipment cleaning conditions, and a new cleaning technology needs to be innovated to overcome the limitations of the traditional cleaning method in cleaning the reactor plates of ethylene glycol synthesis towers from natural gas. Summary of the Invention

[0004] To solve certain technical problems existing in the prior art, the purpose of this application is to provide a cleaning method for the reactor plates of natural gas to ethylene glycol, which can facilitate the cleaning of the coke deposits that are not easily cleaned on the reactor plates, with short required time, low energy consumption, and low labor intensity.

[0005] To solve the above-mentioned existing technical problems, this application is implemented by adopting the following technical solutions:

[0006] A cleaning method for the reactor plates of natural gas to ethylene glycol, the cleaning steps include:

[0007] S1. High-pressure flushing: Use a high-pressure water pipe to conduct high-pressure flushing on each module in the reactor, flush the easily detachable catalyst in each module, and discharge it from the bottom water outlet of the reactor.

[0008] S2. Circulating chemical cleaning: Before cleaning, first lay the cleaning pipeline above the plates of each module, and then use a circulating cleaning device to spray the chemical liquid onto the plates and inner walls of each module through the laid cleaning pipeline for chemical immersion cleaning. Flush and soften the bonded catalyst that was not cleaned thoroughly in step S1 through the circulating chemical liquid, so that the catalyst softens and falls off.

[0009] S3. High-pressure cleaning: After the circulating chemical cleaning is completed, use the high-pressure water pipe again to conduct high-pressure cleaning on the catalyst attached to the plates, and clean the softened and fallen catalyst through high-pressure cleaning.

[0010] Preferably, the circulating cleaning device includes a cleaning pipeline, a circulating pump, a filter, a liquid preparation tank, and a chemical agent tank. The circulating pump is a centrifugal pump. The filter is connected in series between the inlet pipe of the liquid preparation tank and the bottom water outlet of the reactor through a return water pipe. The liquid discharged from the bottom water outlet of the reactor is filtered by the filter and then returned to the liquid preparation tank.

[0011] Preferably, one end of the cleaning pipeline is connected to the water outlet of the circulating cleaning device, and the other end is blocked. A number of water outlet holes are formed on the cleaning pipeline. The chemical liquid is sprayed out through the water outlet holes to conduct chemical flushing on the inner walls of each module. The chemical liquid after flushing flows back into the circulating cleaning device to form a circulating chemical liquid, and then the circulating chemical liquid is injected into each module through the cleaning pipeline to form an immersion flushing. Flush and soften the bonded catalyst that was not cleaned thoroughly by the high-pressure flushing through the circulating chemical liquid, so that the catalyst softens and falls off.

[0012] Preferably, before the circulating chemical cleaning in step S2, hang standard corrosion test pieces that are the same as or similar to the cleaning equipment material in the reactor to monitor the cleaning effect in a timely manner during the cleaning process.

[0013] Preferably, the chemical liquid includes demineralized water and chemical agents, and the circulating immersion time of the chemical liquid is not less than 4 hours.

[0014] Preferably, the head of the circulating pump is not less than 50 m, the pressure is controlled at 0.45 - 0.5 MPa, and the plate temperature is 40°C - 50°C.

[0015] Preferably, the chemical agent includes one or more of corrosion inhibitors, iron ion inhibitors, and sulfamic acid.

[0016] Preferably, the chemical agent is a mixture of corrosion inhibitor, iron ion inhibitor, and sulfamic acid. The steps of adding the chemical agent include:

[0017] A1: First, slowly add the corrosion inhibitor to the flowing and circulating demineralized water in the liquid preparation tank, and continuously detect the concentration of the chemical liquid in real time to make the concentration of the corrosion inhibitor in the chemical liquid 0.3 - 0.5%;

[0018] A2: After passing the test in step A1, add the iron ion inhibitor to the flowing chemical liquid in the liquid preparation tank, and continuously detect the concentration of the chemical liquid in real time to make the concentration of the iron ion inhibitor in the chemical liquid 0.1 - 0.5%;

[0019] A3: After passing the test in step A2, add sulfamic acid to the flowing chemical liquid in the liquid preparation tank, and continuously detect the concentration of the chemical liquid in real time to make the concentration of sulfamic acid in the chemical liquid 4 - 5%. Then, continuously supply the liquid through the circulating cleaning device. After waiting for a sufficient reaction time of more than 2 hours, stop the operation, enter the reactor to take samples inside, and check the coking situation inside the plates;

[0020] A4: According to the sampling inspection results, add 1 - 2% of sulfamic acid and react again. After waiting for a sufficient reaction time of more than 2 hours, stop the operation, enter the reactor again to take samples inside and check the coking situation inside the plates; until the sampling inspection is qualified.

[0021] Preferably, during the chemical cleaning process, conduct a circuit inspection to check whether there is any leakage in the cleaning system and simultaneously monitor various parameters of the chemical cleaning liquid medicine.

[0022] Preferably, the various parameter indicators for monitoring the chemical cleaning liquid medicine include acid concentration, [Fe2+] ion concentration, and [Fe3+] ion concentration.

[0023] Preferably, the waste liquid discharged after the circulating chemical cleaning is neutralized and tested qualified, and then discharged to the underground tank.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] Due to the large overall volume and high cleaning difficulty of the plate reactor, when cleaning the internal half-plates, first rinse with a high-pressure water pipe, wash the easily detachable catalyst in each module of the reactor and discharge it from the bottom water outlet of the reactor; then continuously circulate and spray chemical liquid through the cleaning pipeline in each module, especially on the plates, to achieve chemical immersion cleaning. Through the continuous circulation of the chemical liquid, the firmly adhered coke can be continuously rinsed and softened, causing the coked catalyst to soften and fall off. Finally, after high-pressure cleaning of the catalyst attached to the plates with a high-pressure water pipe, the adhered catalyst in the reactor can be thoroughly cleaned. The time required for the entire cleaning process can be controlled within one week, and the water consumption during the cleaning process is significantly reduced, effectively reducing the labor intensity of personnel. Especially during the subsequent sewage treatment, phased control can also be achieved, thus avoiding the problem of high difficulty in sewage neutralization treatment.

[0026] This cleaning technology not only considers the cleaning effect, but also fully takes into account factors such as energy consumption, time, and environmental protection during the cleaning process, focusing on reducing energy consumption during the cleaning process and minimizing the impact on the environment, which is in line with the current green and sustainable development concept. It can achieve deep cleaning of the surface of the reactor plates, effectively remove stubborn catalysts and deposits, solve the problem that traditional cleaning methods are difficult to thoroughly clean the coke attached to the plates, thereby restoring the original performance of the reactor and improving production efficiency. The cleaned reactor will not affect the lifespan of the catalyst and the quality of the products during subsequent use. Description of the Drawings

[0027] Figure 1 It is a combined structural schematic diagram of the circulating cleaning device and the reactor in the present invention;

[0028] Figure 2 and Figure 3 It is a physical diagram of the coke before cleaning of the plate;

[0029] Figure 4 It is a physical diagram after high-pressure flushing at 1000 MPa in the present invention;

[0030] Figure 5 and Figure 6 It is a physical diagram after cleaning by the new method in the present invention;

[0031] In the figure: 1. Circulating cleaning device; 11. Filter; 12. Liquid preparation tank; 13. Circulation pump; 14. Reagent tank; 15. Cleaning pipeline; 2. Water outlet; 3. Reactor; 4. Module; 5. Plate; 6. Standard corrosion test piece. Detailed Embodiments

[0032] Next, in combination with the accompanying drawings and specific embodiments, the present application will be further described. It should be noted that, on the premise of non-conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0033] In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0034] The terms "first", "second", etc. in the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and do not limit the number of objects. For example, the first object can be one or multiple. In addition, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0035] As Figure 1 shown, a cleaning method for the 3rd plate 5 of a natural gas to ethylene glycol reactor, the cleaning steps include:

[0036] S1. High-pressure flushing: High-pressure flushing is carried out on each module 4 in the reactor 3 through a high-pressure water pipe, and the easily detachable catalyst in each module 4 is flushed out and discharged from the bottom water outlet 2 of the reactor 3;

[0037] S2. Circulating chemical cleaning: Before cleaning, first lay the cleaning pipeline 15 above the plate 5 of each module 4, and then the chemical liquid is sprayed onto the plate 5 and the inner wall of each module 4 through the laid cleaning pipeline 15 by the circulating cleaning device 1 for chemical immersion cleaning. The bonded catalyst not cleaned in step S1 is flushed and softened by the circulating chemical liquid, so that the catalyst softens and falls off;

[0038] S3. High-pressure cleaning: When the circulating chemical cleaning is completed, the catalyst attached to the plate 5 is again subjected to high-pressure cleaning through a high-pressure water pipe, and the softened and fallen catalyst is cleaned up through high-pressure cleaning.

[0039] During the cleaning process of the plate 5 - type reactor 3, due to the large overall volume of the plate 5 - type reactor 3, the small gap (2.5 cm) between plates 5, and the depth of 6 meters, the cleaning difficulty is high. Especially, the coked catalyst is difficult to be rinsed off. Therefore, during the cleaning process, first, it is rinsed with a high - pressure water pipe. After rinsing the easily - detachable catalyst in each module 4 in the reactor 3, it is discharged from the bottom water outlet 2 of the reactor 3. Then, through the cleaning pipeline 15, chemical liquid is continuously circulated and sprayed in each module 4, especially on the plates 5, to achieve chemical immersion cleaning. Through the continuous circulation of the chemical liquid, the firmly - adhered coked substances can be continuously rinsed and softened, making the coked catalyst soften and easy to fall off. Finally, after high - pressure cleaning of the catalyst attached to the plates 5 with a high - pressure water pipe, the adhered catalyst in the reactor 3 can be completely cleaned. The time required for the entire cleaning process can be controlled within one week, and the water consumption during the cleaning process is greatly reduced. The labor intensity of the personnel is also effectively reduced. Especially during the later sewage treatment, phased control can also be achieved, thus avoiding the problem of high difficulty in sewage neutralization treatment.

[0040] Among them, during high - pressure cleaning and high - pressure rinsing, the impact force of the high - pressure water flow is used to remove the residual catalyst and sediment. The pressure range is set at 1000 - 1600 MPa. When directly performing high - pressure rinsing, it is not easy to wash out the softened bonded substances. It is necessary to aim at the areas with severe coking and rinse for a long time to wash them down. Based on the part that has been softened but is difficult to rinse quickly, after modifying the high - pressure rinsing gun head, its water outlet angle is changed to 55°. When rinsing at this angle, the residual catalyst and sediment can be removed more effectively.

[0041] Further improved, the circulating cleaning device 1 includes a cleaning pipeline 15, a circulating pump 13, a filter 11, a liquid - mixing tank 12, and a chemical agent tank 14. The circulating pump 13 is a centrifugal pump. The filter 11 is connected in series between the inlet pipe of the liquid - mixing tank 12 and the bottom water outlet 2 of the reactor 3 through a return water pipe. The liquid discharged from the bottom water outlet 2 of the reactor 3 is filtered by the filter 11 and then refluxed into the liquid - mixing tank 12.

[0042] The circulating cleaning device 1 is composed of a cleaning pipeline 15, a circulating pump 13, a filter 11, a liquid preparation tank 12 and a chemical agent tank 14. The filter is connected in series between the liquid inlet pipe of the liquid preparation tank 12 and the bottom water outlet 2 of the reactor 3 through a return water pipe. It can filter the liquid discharged from the bottom water outlet 2 of the reactor 3 through the filter 11, avoiding the situation that the returned liquid contains a large amount of granular impurities, resulting in pipeline blockage or damage to the circulating pump 13. Moreover, the overall structure is simple, the operation is convenient, and the working stability is high. At the same time, the circulating pump 13 is a centrifugal pump, which occupies a small area, is light in weight and low in cost. When preparing the chemical liquid, it is slowly injected through the chemical agent tank 14, enabling the added chemical agent to be slowly and evenly added to the solution in the liquid preparation tank 12, avoiding the situation that the chemical agent adheres to the module 4 concentratedly after being added, resulting in inaccurate proportion finally.

[0043] Further improvement is made that one end of the cleaning pipeline 15 is connected to the water outlet 2 of the circulating cleaning device 1, and the other end is blocked. A number of water outlet holes are formed on the cleaning pipeline 15. After the chemical liquid is ejected through the water outlet holes, the inner walls of each module 4 are chemically rinsed. The rinsed chemical liquid flows back into the circulating cleaning device 1 to form a circulating chemical liquid, and then the circulating chemical liquid is injected into each module 4 through the cleaning pipeline to form an immersion rinse. The bonded catalyst that is not cleaned thoroughly by the high-pressure rinse is rinsed and softened by the circulating chemical liquid, so that the catalyst softens and falls off.

[0044] Since there are multiple modules 4 in one reactor 3, if spraying structures are installed on each module 4, it will cause the problem of troublesome operation. And manual spraying will increase the labor intensity, and it is difficult to achieve comprehensive spraying with conventional operation methods. Therefore, the cleaning pipeline 15 is improved. Among them, one end of the cleaning pipeline 15 is connected to the water outlet 2 of the circulating pump 13, and the other end is blocked through a cable tie, a plug or integral molding. At the same time, a number of water outlet holes are formed on the corresponding pipe section of the cleaning pipeline 15. Since the cleaning pipeline 15 is placed along the plate 5 of each module 4, when the chemical liquid is injected into each module 4 through the cleaning pipeline 15, the chemical liquid can be ejected outward through the water outlet holes to chemically rinse the inner walls of each module 4 and / or the surface of the plate 5 at the same time, so as to achieve the effect of simultaneous rinsing by one circulating pump 13. During the rinsing process, there is no need for the operator to move the cleaning pipeline 15, thus effectively solving the problems of high labor intensity and difficulty in achieving simultaneous, comprehensive and continuous spraying and soaking of the coked plate 5, and enabling the coked catalyst to be continuously softened.

[0045] Preferably, before the circulating chemical cleaning in step S2, a standard corrosion test piece 6 made of the same or similar material as the cleaning equipment is hung in the reactor 3 to monitor the effect during the cleaning process in a timely manner.

[0046] Due to the relatively large internal volume of the reactor 3 and the gap between the plates 5 (2.5 cm, depth 6 m), during the chemical cleaning process, in order to shorten the cleaning time and observe the effect of the chemical solution, after preparing the chemical agent, it is necessary to enter intermittently for observation. Generally, after preparing the agent, the machine needs to be stopped every half hour, and then enter the interior for observation. During the process of the staff entering and leaving the reactor 3, the liquid supply will be intermittently cut off, resulting in a reduced soaking effect. At the same time, during the observation, it is necessary to specifically search for the target, which affects the cleaning effect. Therefore, in order to conveniently and directly observe the cleaning effect during the continuous cyclic chemical cleaning process, a standard corrosion test piece 6 made of the same or similar material as the cleaning equipment is hung at a suitable position in the reactor 3 where it is convenient to observe. Thus, during the cyclic chemical cleaning process, the operator can directly observe the cleaning effect without stopping the machine and entering the interior, reducing the number of times of entering the interior of the reactor 3.

[0047] Further improvement is that the chemical solution includes demineralized water and a chemical agent, and the cyclic soaking time of the chemical solution is not less than 4 hours.

[0048] The main component of the chemical solution is demineralized water, and the secondary component is the chemical agent. Compared with directly adding the chemical agent to water, the demineralized water can reduce the chloride ion content, and through the cooperation of the chemical agent, the catalyst residue and sediment can be better decomposed, softened and detached from the surface of the components in the reactor 3. In order to ensure the removal effect of the catalyst residue and sediment, the cyclic soaking time of the chemical solution is not less than 6 hours.

[0049] Further improvement is that the head of the circulation pump 13 is not less than 50 m, the pressure is controlled at 0.45 - 0.5 MPa, and the temperature of the plate 5 is 40°C - 50°C.

[0050] In order to ensure the liquid supply effect of the cyclic chemical solution, the head of the circulation pump 13 is not less than 50 m, and the pressure is controlled at 0.45 - 0.5 MPa, which can effectively avoid the situation of insufficient supply pressure and enable the effective supply of the chemical solution to each module 4. Among them, if the temperature of the plate 5 is too low during chemical cleaning, it will cause the coking substances to have a stronger adsorption force on the plate 5, and if the temperature is too high, the coking substances will harden and be difficult to remove. Therefore, the temperature of the plate 5 is 40°C - 50°C, which can make the chemical solution have a better effect on removing the coking substances compared with the conventional state, the coking substances are easier to soften, and it is also easier to spray the liquid to the required range.

[0051] Further improvement is that the chemical agent includes one or more of corrosion inhibitors, iron ion inhibitors and sulfamic acid.

[0052] When cleaning the plate 5, the selection of chemical agents is crucial. It must be able to effectively decompose and remove the catalyst residues and deposits on the surface of the plate 5, while not causing corrosion or damage to the material of the plate 5. Since there is currently no chemical agent for cleaning the coke deposits on the plates 5 of the plate 5 type reactor 3, it is difficult to determine which of the numerous chemical agents can actually achieve the effect of accelerating the shedding. Therefore, during the preliminary cleaning process, our company has conducted repeated experiments on the selection and ratio of chemical cleaning methods and chemical agents. It has been found that when one or more of a corrosion inhibitor, an iron ion inhibitor, and sulfamic acid are added to the demineralized water for cleaning, the softening and shedding of catalyst residues and deposits can be accelerated.

[0053] Preferably, the chemical agent is a mixture of a corrosion inhibitor, an iron ion inhibitor, and sulfamic acid. The steps for adding the chemical agent include:

[0054] A1: First, slowly add the corrosion inhibitor to the flowing and circulating demineralized water in the liquid preparation tank 12, and continuously detect the concentration of the chemical liquid in real time to make the concentration of the corrosion inhibitor in the chemical liquid 0.3 - 0.5%;

[0055] A2: After passing the test in step A1, add the iron ion inhibitor to the flowing chemical liquid in the liquid preparation tank 12, and continuously detect the concentration of the chemical liquid in real time to make the concentration of the iron ion inhibitor in the chemical liquid 0.1 - 0.5%;

[0056] A3: After passing the test in step A2, add sulfamic acid to the flowing chemical liquid in the liquid preparation tank 12,

[0057] and continuously detect the concentration of the chemical liquid in real time to make the concentration of sulfamic acid in the chemical liquid 4 - 5%. Then, continuously supply the liquid through the circulating cleaning device 1. After waiting for a sufficient reaction time of more than 2 hours, stop the operation, enter the reactor 3 to take samples, and check the coke formation situation inside the plate 5;

[0058] A4: According to the sampling inspection situation, add 1 - 2% of sulfamic acid and react again. After waiting for a sufficient reaction time of more than 2 hours, stop the operation, enter the reactor 3 again to take samples and check the coke formation situation inside the plate 5; until the sampling inspection is qualified.

[0059] Although the softening and decomposition effects of catalyst residues and deposits can be improved by increasing corrosion inhibitors, iron ion inhibitors, and sulfamic acid, when the content of chemical agents is insufficient, the cleaning effect is not obvious. When the addition is excessive, it will not only cause subsequent environmental pollution but also damage the surface of the plate 5 during the cleaning process. For example, when sulfamic acid is in excess, it will corrode the plate 5 and cause the equipment to be damaged and unusable. Therefore, it is necessary to precisely proportion the chemical agents. After repeatedly testing the proportions of various chemical agents, the current optimal solution was finally determined, which is a mixture of corrosion inhibitors, iron ion inhibitors, and sulfamic acid. After the addition is completed, the concentration of the corrosion inhibitor is 0.3 - 0.5%, sulfamic acid is 8 - 10%, and the iron ion inhibitor is 0.1 - 0.5%. Its unique chemical agent proportioning can be optimized for different types of deposits, thus achieving a more efficient cleaning effect. During the cleaning process, the temperature of the circulating liquid is controlled at 40 - 50°C, and the temperature of the plate 5 is controlled between 40 - 50°C. It is necessary to precisely control the temperature, pressure, and time to ensure that the cleaning agent reacts fully with the catalyst and deposits without damaging the plate 5 of the reactor 3, and it is also more convenient during the subsequent neutralization treatment.

[0060] Among them, during the cyclic chemical cleaning process, first, desalted water is used for cyclic cleaning for at least 2 hours or more. Generally, the cyclic cleaning time with desalted water is 4 - 10 hours. Then, the corrosion inhibitor is slowly added to the flowing desalted water. During the addition of the corrosion inhibitor, the concentration of the formulated chemical liquid is detected to make the concentration of the corrosion inhibitor in the chemical liquid reach 0.3 - 0.5%. Then, the iron ion inhibitor is slowly added to the chemical liquid, and the concentration of the chemical liquid is also detected to make the concentration of the iron ion inhibitor in the chemical liquid be 0.1 - 0.5%. Finally, sulfamic acid is slowly added to the flowing chemical liquid to make the concentration of sulfamic acid stable between 4 - 5%. After continuous cyclic liquid supply through the cyclic cleaning device 1, it reacts with the internal adherents. After waiting for a sufficient reaction time of 2 hours or more, the operation is stopped, and samples are taken inside the reactor 3 to check the coking situation inside the plate 5. When the coking removal effect is significantly increased, the chemical agent is finalized. When the effect is found to be insufficient after sampling, 1 - 2% of sulfamic acid is added again according to the sampling inspection situation and then the reaction is carried out again. After waiting for a sufficient reaction time of 2 hours or more, the operation is stopped, and samples are taken inside the reactor 3 again to check the coking situation inside the plate 5. It is stopped until the sampling inspection is qualified or the content of sulfamic acid reaches 10%. Among them, the cyclic cleaning time of the chemical liquid added with chemical agents does not exceed 48 hours, and the maximum amount of sulfamic acid added subsequently is 5%. Excessive addition will corrode the plate 5 and cause the equipment to be damaged and unusable. Through this proportioning cleaning, while ensuring the cleaning effect, the usage amount of chemical agents is minimized to reduce environmental pollution. At the same time, by precisely controlling the proportioning of the cleaning agent and the cleaning time, the efficiency and stability of the cleaning process are ensured.

[0061] It is further improved that during the chemical cleaning process, the cleaning system is inspected for leaks on a round-robin basis while monitoring various parameters of the chemical cleaning solution; the monitored parameter indicators of the chemical cleaning solution include acid concentration to avoid corrosion of the plate 5; the waste liquid discharged after the cyclic chemical cleaning is neutralized and tested qualified before being discharged to the underground tank.

[0062] During the actual cleaning process of each module 4 with coked plates 5 in the plate 5 type ethylene glycol reactor 3, first, the staff enters the reactor 3 and uses a high-pressure water pipe to conduct high-pressure water flushing on each module 4. After flushing off the adhesives that can be washed off by the high-pressure water gun, the sewage flows out through the water outlet 2 at the bottom of the plate 5 type ethylene glycol reactor 3. The time required for each module 4 to complete the preliminary flushing is generally within one working day; with the increase of high-pressure water pipes and operators, the time can be correspondingly shortened;

[0063] Then, the cleaning pipeline 15 is laid above the plates 5 of each module 4, and a circulating cleaning device 1 is installed between the cleaning pipeline 15 and the water outlet 2 of the plate 5 type ethylene glycol reactor 3. Among them, the filter 11 is connected in series between the inlet pipe of the liquid distribution tank 12 and the water outlet 2 at the bottom of the reactor 3 through a return water pipe. The circulating chemical liquid is transported into the cleaning pipeline 15 through the circulating pump 13, and the liquid spraying treatment of each module 4 is realized through the water outlet holes on the cleaning pipeline 15, so that the areas to be cleaned can be continuously covered by the chemical liquid. The downward flowing chemical liquid can carry away some impurities such as softened and peeled coking substances and flow back to the filter 11 uniformly from the water outlet 2 at the bottom of the reactor 3. After the coking substances and other impurities are filtered by the filter 11, the chemical liquid flows back into the liquid distribution tank 12 again, and then is pumped out by the circulating pump 13 to form a cycle. After adding enough circulating chemical liquid in the early stage, continuous flushing of each module 4 can be realized through a fixed total amount of chemical liquid, thus effectively reducing the waste of water resources. And during the flushing process, the coking substances can be in a state of being soaked for a long time. After long-term soaking and flushing, the firmly adhered coking substances can be effectively softened and separated. Among them, the duration of the cyclic chemical cleaning cannot be less than 4 hours, generally in units of half a day, one night or one day. For example, when the laid pipeline is close to getting off work, after preparing the circulating chemical liquid, it can be in the cyclic flushing stage all night, and when starting in the morning, there is enough time to finish the work before getting off work, which can be specifically controlled according to the degree of coking;

[0064] When the chemical cleaning is completed, neutralizing agents are injected into the chemical liquid in the reagent tank 14 to neutralize the circulating chemical liquid. The waste liquid discharged after the cyclic chemical cleaning is neutralized and tested qualified before being discharged to the underground tank. The chemical cleaning process can generally be completed within 24 hours;

[0065] Finally, the operator enters the plate 5 type ethylene glycol reactor 3 again, and uses a high-pressure water pipe to perform high-pressure cleaning on the catalyst attached to the plate 5. Through high-pressure cleaning, the softened coked catalyst is thoroughly cleaned. As Figure 5 and Figure 6 shown, the internal cleaning of the plate 5 type ethylene glycol reactor 3 is finally completed. Since in the whole operation process, the staff basically does not need to perform targeted treatment through special tools anymore, the operation time of the last step can be effectively shortened, and the labor intensity of the operator can also be effectively reduced. The operation can be shortened from the original 11 days to 3 - 4 working days. With the increase of high-pressure water pipes and operators, the time can be correspondingly shortened; after cleaning the plate 5 type ethylene glycol reactor 3 by this method, the time can be shortened from the original 12 days to within 7 days, and the water pressure requirement for the high-pressure water pipe can be lower, and the waste of water resources is less. Especially when a filter 11 is always installed at the bottom of the plate 5 type ethylene glycol reactor 3, the waste liquid flushed down can be more environmentally friendly after being discharged. This cleaning technology not only considers the cleaning effect, but also fully considers factors such as energy consumption, time, and environmental protection during the cleaning process, pays attention to reducing energy consumption during the cleaning process and reducing the impact on the environment, and conforms to the current green and sustainable development concept. It can achieve deep cleaning of the surface of the plate 5 of the reactor 3, effectively remove stubborn catalysts and deposits, solve the problem that traditional cleaning methods are difficult to thoroughly clean the coked substances attached to the plate 5, thereby restoring the original performance of the reactor 3 and improving production efficiency. The reactor 3 after cleaning will not affect the service life of the catalyst and the product quality during the later use process.

[0066] This solution can not only effectively remove the catalyst and deposits on the surface of the plate 5 of the reactor 3, but also minimize energy consumption and environmental impact while ensuring the cleaning effect. In addition, this cleaning technology also has good operability and stability, providing a strong guarantee for the long-term stable operation of the plate 5 of the natural gas to ethylene glycol reactor 3.

[0067] The above-mentioned embodiments are only the preferred embodiments of the present application, and the protection scope of the present application cannot be limited by this. Any non-substantial changes and substitutions made by those skilled in the art based on the present application belong to the scope required to be protected by the present application.

Claims

1. A cleaning method for the reactor plates of ethylene glycol produced from natural gas, characterized in that: The cleaning steps include: S1. High-pressure flushing: Use a high-pressure water pipe to perform high-pressure flushing on each module (4) inside the reactor (3), flush the easily detachable catalyst inside each module (4), and discharge it from the bottom water outlet (2) of the reactor (3). S2. Circulating chemical cleaning: Before cleaning, first lay the cleaning pipeline (15) above the plates (5) of each module (4), and then use the circulating cleaning device (1) to spray the chemical liquid onto the plates (5) and inner walls of each module (4) through the laid cleaning pipeline (15) for chemical immersion cleaning. The bonded catalyst not cleaned by the high-pressure flushing in step S1 is flushed and softened by the circulating chemical liquid, so that the catalyst softens and falls off. S3. High-pressure cleaning: After the circulating chemical cleaning is completed, use the high-pressure water pipe again to perform high-pressure cleaning on the catalyst attached to the plates (5), and clean the softened and fallen catalyst through high-pressure cleaning.

2. The cleaning method of a reactor plate for producing ethylene glycol from natural gas according to claim 1, wherein: Preferably, the circulating cleaning device (1) includes a cleaning pipeline (15), a circulating pump (13), a filter (11), a liquid preparation tank (12), and a chemical agent tank (14). The circulating pump (13) is a centrifugal pump. The filter (11) is connected in series between the inlet pipe of the liquid preparation tank (12) and the bottom water outlet (2) of the reactor (3) through a return water pipe. The liquid discharged from the bottom water outlet (2) of the reactor (3) is filtered by the filter (11) and then returned to the liquid preparation tank (12).

3. The cleaning method of the reactor plate of ethylene glycol produced from natural gas according to claim 2, wherein: One end of the cleaning pipeline (15) is connected to the water outlet (2) of the circulating cleaning device (1), and the other end is blocked. A number of water outlet holes are formed on the cleaning pipeline (15). The chemical liquid is sprayed through the water outlet holes to perform chemical flushing on the inner walls of each module (4). The flushed chemical liquid flows back into the circulating cleaning device (1) to form a circulating chemical liquid, and then the circulating chemical liquid is injected into each module (4) through the cleaning pipeline to form an immersion flushing. The bonded catalyst not cleaned by the high-pressure flushing is flushed and softened by the circulating chemical liquid, so that the catalyst softens and falls off.

4. The cleaning method of a reactor plate for producing ethylene glycol from natural gas according to claim 3, wherein: The head of the circulating pump (13) is not less than 50m, the pressure is controlled at 0.45 - 0.5MPa, and the temperature of the plates (5) is 40°C - 50°C.

5. The cleaning method of the reactor plate of ethylene glycol produced from natural gas according to claim 1, characterized in that: Before the circulating chemical cleaning in step S2, hang a standard corrosion test piece (6) made of the same or similar material as the cleaning equipment inside the reactor (3) to monitor the cleaning effect in real time.

6. A cleaning method for a reactor plate of ethylene glycol produced from natural gas according to any one of claims 1 to 4, characterized in that: The chemical liquid includes demineralized water and chemical agents, and the circulating immersion time of the chemical liquid is not less than 4 hours.

7. A cleaning method for the reactor plates of ethylene glycol produced from natural gas according to claim 5, characterized in that: The chemical agents include one or more of corrosion inhibitors, iron ion inhibitors, and sulfamic acid.

8. The cleaning method of the reactor plate of the natural gas to ethylene glycol according to claim 6, characterized in that: The chemical agent is a mixture of a corrosion inhibitor, an iron ion inhibitor, and sulfamic acid. The steps for adding the chemical agent include: A1: First, slowly add the corrosion inhibitor to the flowing and circulating demineralized water in the liquid preparation tank (12), and detect the concentration of the chemical liquid in real time to make the concentration of the corrosion inhibitor in the chemical liquid 0.3 - 0.5%. A2: After passing the test in step A1, an iron ion inhibitor is added to the flowing chemical solution in the liquid preparation tank (12), and the concentration of the chemical solution is detected in real time so that the concentration of the iron ion inhibitor in the chemical solution is 0.1-0.5%; A3: After passing the test in step A2, sulfamic acid is added to the flowing chemical solution in the liquid preparation tank (12), and the concentration of the chemical solution is detected in real time so that the concentration of sulfamic acid in the chemical solution is 4-5%. Then, continuous circulating liquid supply is carried out through the circulating cleaning device (1). After waiting for a sufficient reaction time of more than 2 hours, the operation is stopped, and samples are taken inside the reactor (3) to check the coking situation inside the plate (5); A4: According to the sampling inspection situation, 1-2% of sulfamic acid is added and the reaction is carried out again. After waiting for a sufficient reaction time of more than 2 hours, the operation is stopped, and samples are taken inside the reactor (3) again to check the coking situation inside the plate (5); until the sampling inspection is qualified.

9. The cleaning method of a reactor plate for producing ethylene glycol from natural gas according to claim 7, characterized in that: During the chemical cleaning process, inspect the cleaning system for leakage on a circuit basis and monitor various parameters of the chemical cleaning liquid medicine at the same time.

10. A cleaning method for the reactor plates of ethylene glycol produced from natural gas according to claim 7, characterized in that: The waste liquid discharged after cyclic chemical cleaning is neutralized and tested qualified, and then discharged to the underground tank.

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