A method of regenerating a filter

Abstract

This invention relates to a method and system for regenerating filters (also known as filter elements), specifically to a method and system for regenerating filters in the energy and chemical industry. The regeneration method includes: cleaning with a cleaning solvent; high-temperature calcination; immersion in an acidic solution; and ultrasonic cleaning. Using the regeneration method described in this invention, the filtration flux of the filter can be restored to more than 95% of the filtration flux of a brand-new filter element. Furthermore, this regeneration method is highly efficient, reliable, simple to operate, and widely applicable.

Description

Technical Field

[0001] This invention relates to a regeneration process for filters (also known as filter elements), specifically to a regeneration method and system for filters used in the energy and chemical industry. Background Technology

[0002] Slurry-bed and fluidized-bed reactors offer advantages such as uniform temperature distribution, efficient removal of reaction heat, online solid replacement, and ease of large-scale production, leading to their widespread application in energy and chemical industries (e.g., petrochemical processes like Fischer-Tropsch synthesis). In these reactors, liquid products are continuously generated as the reaction proceeds. The accumulation of these liquid products causes the liquid level to rise, necessitating timely online removal to maintain a stable liquid level. However, to ensure stable production and obtain clarified liquid products, it is crucial to retain the solids and solid residues mixed with the liquid products within the reactor during removal. Therefore, filters are required within the reactor to achieve efficient separation of liquid products from solids and solid residues.

[0003] While filters installed in reactors used in the energy and chemical industry can effectively solve the problem of efficient separation of solid and liquid components, fine solid particles accumulate in the filter channels over time, causing continuous clogging and irreversible fouling, leading to a continuous decrease in filtration flux. Therefore, it is necessary to regenerate the clogged filter to restore filtration flux and ensure filtration efficiency. Currently, commonly used filter regeneration methods mainly fall into two categories: online backwashing and offline regeneration.

[0004] Patent CN102688724B discloses a method for filtering and backflushing Fischer-Tropsch wax and catalyst in a slurry bed reactor for Fischer-Tropsch synthesis. This method utilizes backflushing of the filter during production to clean the filter in the slurry bed reactor. However, because the filter tube's pores are not straight, some fine solid particles easily become stuck inside the pores after entering. These particles cannot be flushed out during backflushing, and their accumulation causes filter tube blockage, preventing the reactor from operating normally and requiring shutdown and filter replacement. Therefore, this method has the drawback of failing to remove these particles stuck in the filter tube.

[0005] Patent application CN108654214A discloses a regeneration method and system for Fischer-Tropsch synthesis filter elements. The method involves cleaning the filter element with steam to remove heavy oil, then soaking and circulating the filter element with an alkaline solution, and finally drying it with hot air. Because fine solid particles typically clog the micropores of the filter very tightly, this method can only remove the heavy oil clogging the filter element, but cannot completely remove the solid particles stuck in the micropores.

[0006] Patent CN201710485626X discloses a cleaning and regeneration agent and a method for cleaning and regenerating Fischer-Tropsch filter elements. The method primarily involves sequentially soaking the filter element in a cleaning and regeneration agent comprising a passivating cleaning agent and a rinsing cleaning agent to achieve cleaning and regeneration. However, this method still falls short because solid particles are often very tightly trapped in the gaps of the filter element, and the Fischer-Tropsch filter element has residual wax and colloids. The melting point of wax is above 100℃, and the colloids are difficult to remove. Therefore, this method is still insufficient to completely clean and regenerate the filter element.

[0007] As mentioned above, the existing regeneration methods for reactor filters used in the energy and chemical industry are mainly divided into two categories: backflushing cleaning in production mode and cleaning with cleaning agents in offline mode, such as steam cleaning followed by alkaline cleaning, or cleaning with the specific cleaning agents mentioned above. The advantage of the first method is that backflushing cleaning can be performed without disassembling the filter, but its regeneration effect is poor, and it can only remove larger particles, not effectively removing fine solid particles. The second method involves disassembling the filter and cleaning it with a cleaning agent (e.g., steam cleaning to remove heavy oil, followed by soaking in alkaline solution). This method can remove most particles, but it is difficult to remove solid particles stuck in the micropores of the filter. Summary of the Invention

[0008] In view of the problems existing in the prior art, the inventors have discovered a highly efficient and reliable regeneration method and regeneration system for filters used in the energy and chemical industry (e.g., petrochemical industry, such as Fischer-Tropsch synthesis). Using this regeneration method, the filtration flux of the filter element can be restored to more than 95% of the filtration flux of a brand new filter element.

[0009] One aspect of the present invention provides a method for regenerating a filter, the method comprising:

[0010] (1) Clean the filter to be regenerated with preheated cleaning solvent to obtain a cleaned filter;

[0011] (2) The cleaned filter is calcined to obtain a calcined filter;

[0012] (3) Soak the roasted filter in an acidic solution;

[0013] (4) The filter soaked in step (3) is ultrasonically cleaned to obtain a regenerated filter.

[0014] In some embodiments of the present invention, the cleaning equipment described in the present invention is used to carry out the regeneration method described in the present invention. The cleaning equipment is particularly useful for implementing the cleaning step (1) of the regeneration method described in the present invention. The equipment includes: a solvent heating tank, a centrifugal pump, a filter support frame, and a filter cleaning tank.

[0015] The technical solution provided by this invention has the following beneficial effects:

[0016] 1. The regeneration method of the present invention has the advantages of high efficiency, reliability, simple operation and wide applicability.

[0017] 2. By using the method of the present invention to regenerate the filter of the reactor, the filtration flux of the filter element can be restored to more than 95% of that of a brand new filter element, allowing the filter to be reused and significantly reducing investment costs. Attached Figure Description

[0018] The accompanying drawings are part of the specification and, together with the detailed description, provide a further explanation of the invention, but are not intended to limit the invention.

[0019] Figure 1 This is a schematic diagram of a filter cleaning device according to an embodiment of the present invention;

[0020] The reference numerals in the attached drawings are as follows: 1. Centrifugal pump; 2. Filter cleaning tank; 3. Filter to be regenerated; 4. Cleaning tank drain valve; 5. Solvent heating tank; 6, 7. Valves; 8. Overflow weir; 9. Cleaning solvent; 10. Filter support frame. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below. The specific embodiments described herein are for illustration and explanation only, and are not intended to limit the present invention.

[0022] This invention provides a method for regenerating a filter, the method comprising:

[0023] (1) Clean the filter to be regenerated with preheated cleaning solvent to obtain a cleaned filter;

[0024] (2) The cleaned filter is calcined to obtain a calcined filter;

[0025] (3) Soak the roasted filter in an acidic solution;

[0026] (4) The filter soaked in step (3) is ultrasonically cleaned to obtain the regenerated filter.

[0027] In this invention, the filter specifically refers to a filter used in reactors in the energy and chemical industry, particularly the petrochemical industry. For example, in this invention, the filter to be regenerated is a filter used in slurry beds and fluidized beds. In a preferred embodiment, the filter is a filter used in Fischer-Tropsch synthesis.

[0028] In some embodiments, the filter to be regenerated is any filter that can be used in the energy and chemical industry (especially the petrochemical industry), for example, a filter used in a reactor (e.g., a reactor for Fischer-Tropsch synthesis). For example, the filter may be one or more of commercially available sintered metal wire mesh filters, wedge mesh filters, sintered metal powder filters, sintered metal fiber felt filters, porous ceramic filters, etc., preferably one of sintered metal wire mesh filters, wedge mesh filters, or sintered metal powder filters.

[0029] In this invention, the filter to be regenerated is subjected to the cleaning step (1) to mainly remove the solid particles that adhere to the surface of the filter and that are easily detached in the micropores. At the same time, it can also clean away substances that are easily solidified, viscous, corrosive or toxic that adhere to the filter, so as to facilitate subsequent cleaning processes.

[0030] In some embodiments, the cleaning solvent is a petroleum product with an initial boiling point above 70°C, a Fischer-Tropsch synthesis product, other lipophilic organic compounds, or mixtures thereof; preferably one or more of naphtha, gasoline, light diesel oil, heavy diesel oil, and wax oil; more preferably one or more of Fischer-Tropsch synthesis products, such as Fischer-Tropsch naphtha, Fischer-Tropsch gasoline, Fischer-Tropsch light diesel oil, Fischer-Tropsch heavy diesel oil, and Fischer-Tropsch wax oil. Lipophilic organic compounds are readily known to those skilled in the art; for example, in this invention, other lipophilic organic compounds may be selected from organic compounds containing alkyl, phenyl, cycloalkyl, or other similar groups.

[0031] In this invention, the preheating temperature of the cleaning solvent is 20℃-300℃, preferably 30℃-200℃. The preheating of the cleaning solvent can be carried out in a cleaning solvent heating tank, which may be equipped with a steam jacket or an electric heating jacket.

[0032] In embodiments of the present invention, the cleaning operation employed in step (1) may be either soaking and / or rinsing. For example, in step (1), the filter to be regenerated may be cleaned by soaking only; or, the filter to be regenerated may be cleaned by rinsing only; or, in cleaning step (1), soaking and rinsing may be combined. For example, rinsing or soaking may be performed for a predetermined period of time, followed by another predetermined period of time, and may be performed alternately multiple times as needed.

[0033] The filter to be regenerated can be soaked for 10-120 minutes, preferably 30-60 minutes, ideally until the cleaning solvent completely submerges it. During rinsing, the conditions for rinsing the filter with the cleaning solvent can be: flow rate of 0.5-2 m / s; rinsing time of 10-120 minutes, preferably 30-60 minutes.

[0034] In this invention, the filter to be regenerated is parallel to the flow direction of the cleaning solvent, that is, the cleaning solvent rinses the filter surface and micropores.

[0035] In some preferred embodiments, the cleaning solvent rinsing method may be solvent circulation rinsing.

[0036] In some preferred embodiments, the cleaning solvent may be a clean cleaning solvent (meaning a cleaning solvent that is substantially free of solid particles), or the cleaning solvent may be subjected to simple impurity removal to reduce the solid particle content to below 100 ppm and then recycled. In a further preferred embodiment, the simple impurity removal method for the cleaning solvent may be one or more of the following: settling, centrifugation, and filtration.

[0037] More preferably, before cleaning in step (1), the filter element can be liquid-backblown with a cleaning solvent to remove some impurities.

[0038] In some preferred embodiments, in order to achieve a better regeneration effect, step (1) may be performed once or multiple times, for example, 1 to 10 times.

[0039] In step (2), the cleaned filter is calcined to burn off the organic matter in the solid particles and the difficult-to-remove organic matter (such as colloids, coke, etc.) adhering to the filter at high temperature. The calcination conditions can be: temperature of 300℃-700℃, preferably 400-650℃; calcination time of 10-40h, preferably 12-24h. In a preferred embodiment, the calcination is carried out after reaching the predetermined calcination temperature at a heating rate of 5-40℃ / min, preferably 10-30℃ / min.

[0040] In a preferred embodiment, the roasting can be carried out in a muffle furnace.

[0041] In this invention, in step (3), an acidic solution is used to soak the solid particles that are firmly stuck in the micropores of the filter, so that they can be easily detached.

[0042] In step (3) of this invention, the acidic solution is sufficient as long as it can readily dissolve the solid particles in the filter without corroding the filter element. For example, the solid particles may be catalysts, filter aids, or adsorbents. In a preferred embodiment, the acidic solution may be one or more inorganic or organic acids, and the pH range of the acidic solution is preferably maintained between 0.5 and 6.5, preferably 1 to 6, for example, maintained at pH 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, or 6.5. For example, the acidic solution may be one or a mixture of sulfuric acid, hydrochloric acid, nitric acid, citric acid, aminosulfonic acid, phosphoric acid, formic acid, acetic acid, or oxalic acid, preferably oxalic acid, phosphoric acid, aminosulfonic acid, citric acid, or a mixture thereof. In embodiments of this invention, the acidic solution is preferably an aqueous solution, such as an acidic aqueous solution.

[0043] In a preferred embodiment, the soaking conditions in step (3) are as follows: soaking time is 1-15 hours, preferably 3-10 hours; soaking temperature is 20-90°C, preferably 30-70°C. Preferably, the filter is completely submerged in the acidic solution.

[0044] Before performing step (3) of the present invention, the calcined filter is cooled to 20-100°C, preferably 40-90°C.

[0045] In step (4) of this invention, the solid particles stuck in the filter micropores are further removed by ultrasonic cleaning. Preferably, the ultrasonic cleaning conditions are as follows: the ultrasonic solvent is deionized water or a commercially available water-based cleaning agent, such as trichloroethane or trichloroethylene, with deionized water being preferred; the ultrasonic frequency is 5-50 kHz; and the ultrasonic power is 0.5-2 W / cm². -2 The time is 10-200 min, preferably 20-60 min. In a preferred embodiment, during the ultrasound process, the temperature of the ultrasound solvent is 20-90℃, preferably 40-80℃.

[0046] In a preferred embodiment, before the ultrasonic cleaning in step (4), the acidic solution remaining on the filter after soaking in step (3) can be removed by purging with steam and / or hot air. The purging conditions are only required to remove the residual acidic solution from the filter. In a preferred embodiment, the steam purging time can be 5-60 minutes, preferably 10-40 minutes.

[0047] In a preferred embodiment, after the ultrasonic cleaning in step (4), the invention further includes a drying step. For example, the filter is dried using hot air. This drying step prevents the filter from being contaminated by microorganisms and also prevents water and other impurities from being introduced into the Fischer-Tropsch synthesis reactor when the filter is reinstalled.

[0048] The term "filtration flux" as used in this invention refers to the amount of fluid passing through a unit filter area per unit time, typically expressed in meters (m). 3 .m -2 .h -1 express.

[0049] The cleaning step (1) of the regeneration method described in this invention can be implemented using the following cleaning equipment, which includes:

[0050] Solvent heating tank;

[0051] Centrifugal pump;

[0052] Filter support frame;

[0053] Filter cleaning tank;

[0054] The filter rinsing tank is connected to the solvent heating tank via a centrifugal pump in a fluid communication manner.

[0055] In some preferred embodiments, the solvent heating tank is equipped with a steam jacket or an electric heating jacket for heating the cleaning solvent.

[0056] In some preferred embodiments, the filter support frame is disposed inside the filter cleaning tank to support and fix the filter to be filtered for easy cleaning.

[0057] In some preferred embodiments, the filter cleaning tank is provided with an overflow weir to maintain a certain liquid level in the rinsing tank and to trap most of the particles, wherein the overall height of the overflow weir is about 1 / 3 to 2 / 3 of the height of the filter cleaning tank.

[0058] In some preferred embodiments, the upper part of the overflow weir has micropores with a size of 30-200 μm.

[0059] In some preferred embodiments, the bottom of the filter cleaning tank is sloped, and a drain valve is provided at the lowest point to periodically discharge solid particles from the bottom of the filter cleaning tank.

[0060] In some preferred embodiments, after the cleaning solvent has completed the filter cleaning, it is periodically discharged along with the solid particles deposited at the bottom of the filter rinsing tank through a drain valve installed at the bottom of the tank. The cleaning solvent discharged from the filter cleaning tank can be recycled after impurity removal.

[0061] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0062] As shown in the attached diagram, the filter to be regenerated is placed horizontally on the filter support in the filter cleaning tank so that the filter element and the solvent flow direction are horizontal. The filter support frame is placed upright in the filter cleaning tank. The filters to be regenerated are neatly and fixedly stacked on the filter support frame to prevent the filters to be regenerated from bumping and damaging each other during rinsing, and to ensure that the filter is parallel to the cleaning and dissolving flow direction, which facilitates rinsing.

[0063] The cleaning solvent is placed in a solvent heating tank and preheated to 20℃-300℃, preferably 30℃-200℃. Then, the centrifugal pump is started, valve 7 is opened, and the centrifugal pump 1 is activated to deliver the cleaning solvent to the filter cleaning tank 2. When the solvent level in the filter cleaning tank 2 exceeds the top of the filter, valve 6 is opened to gradually establish solvent circulation. The filter cleaning tank 2 is equipped with an overflow weir 8 with 30-200μm micropores in the upper middle section and no pores in the lower middle section. The overall height of the overflow weir 8 is approximately 1 / 3-2 / 3 of the height of the filter cleaning tank. Its main function is to ensure that, during stable circulation of the cleaning solvent, as many particles as possible are retained in the filter cleaning tank 2.

[0064] Depending on the degree of filter contamination, the cleaning solvent continuously rinses and cleans the filter for 10-120 minutes (e.g., 30-60 minutes). A significant amount of solid particles will remain in the filter cleaning tank 2. At this point, centrifugal pump 1, valves 6 and 7 are closed, and the drain valve 4 is opened to discharge the solvent containing solid particles, thus cleaning the inside of the filter cleaning tank 2. The solvent discharged from the drain valve 4 is collected, allowed to settle, and the supernatant can be reused after simple filtration and adsorption. Each batch of filters awaiting regeneration will have most of the residual solid particles removed after one or more rinses with the cleaning solvent.

[0065] After rinsing with a cleaning solvent, the filter is calcined in a muffle furnace at a temperature of 300℃-700℃, preferably 400-650℃, for 10-40 hours, preferably 12-24 hours, with a heating rate of 5-40℃ / min, preferably 10-30℃ / min. After calcination and cooling, the filter is removed from the muffle furnace and immersed in an acidic solution preheated to 20-90℃, preferably 30-70℃, for 1-15 hours (e.g., 3-10 hours). After immersion, the filter is removed.

[0066] Optionally, the filter removed from the acidic solution is purged with steam for 5-60 minutes, preferably 10-40 minutes, to remove residual acidic solution. Then, the filter is cleaned ultrasonically at 20-90°C for 10-200 minutes to obtain a regenerated filter. After ultrasonic cleaning, the filter can be dried with hot air.

[0067] Therefore, the technical solution of the present invention can be defined by the following paragraphs:

[0068] 1. A method for regenerating a filter, the method comprising:

[0069] (1) Clean the filter to be regenerated with preheated cleaning solvent to obtain a cleaned filter;

[0070] (2) The cleaned filter is calcined to obtain a calcined filter;

[0071] (3) Soak the roasted filter in an acidic solution;

[0072] (4) The filter soaked in step (3) is ultrasonically cleaned to obtain the regenerated filter.

[0073] 2. The method as described in paragraph 1, wherein the filter is a filter used in the energy and chemical industry.

[0074] 3. The method as described in paragraph 1 or 2, wherein the filter is the filter used in Fischer-Tropsch synthesis.

[0075] 4. The method as described in any one of paragraphs 1-3, wherein the filter is a filter used in slurry beds and fluidized beds.

[0076] 5. The method as described in any one of paragraphs 1-4, wherein the filter is selected from one or more of the following: sintered metal wire mesh filter, wedge mesh filter, sintered metal powder filter, sintered metal fiber felt filter, and porous ceramic filter.

[0077] 6. The method as described in any one of paragraphs 1-5, wherein the cleaning solvent is a petroleum product, a Fischer-Tropsch synthesis product, other lipophilic organic compounds, or a mixture thereof with an initial boiling point above 70°C.

[0078] 7. The method as described in any one of paragraphs 1-6, wherein the cleaning solvent is one or more of naphtha, gasoline, light diesel oil, heavy diesel oil, and wax oil.

[0079] 8. The method as described in any one of paragraphs 1-6, wherein the cleaning solvent is one or more of Fischer-Tropsch naphtha, Fischer-Tropsch gasoline, Fischer-Tropsch light diesel oil, Fischer-Tropsch heavy diesel oil, and Fischer-Tropsch wax oil.

[0080] 9. The method as described in any one of paragraphs 1-8, wherein the preheating temperature of the cleaning solvent is 20°C-300°C.

[0081] 10. The method as described in paragraph 9, wherein the preheating temperature of the cleaning solvent is preferably 30°C-200°C.

[0082] 11. The method as described in any one of paragraphs 1-10, wherein in step (1), the cleaning operation is selected from soaking and rinsing.

[0083] 12. The method as described in paragraph 11, wherein the soaking time is 10-120 min.

[0084] 13. The method as described in paragraph 12, wherein the soaking time is 30-60 minutes.

[0085] 14. The method as described in paragraph 11, wherein the rinsing conditions are: flow rate of 0.5-2 m / s; time of 10-120 min.

[0086] 15. The method as described in paragraph 14, wherein the rinsing time is 30-60 minutes.

[0087] 16. The method as described in paragraph 14 or 15, wherein the rinsing method is a cleaning solvent circulation rinse.

[0088] 17. The method as described in any one of paragraphs 1-16, wherein step (1) is performed 1-10 times.

[0089] 18. The method of any one of paragraphs 1-17, wherein prior to step (1), the method comprises a step of liquid backflushing the filter element with the cleaning solvent.

[0090] 19. The method as described in any one of paragraphs 1-18, wherein in step (2), the calcination conditions are: a temperature of 300℃-700℃; and a calcination time of 10-40h.

[0091] 20. The method as described in paragraph 19, wherein the calcination temperature is 400-650°C.

[0092] 21. The method as described in paragraph 19 or 20, wherein the calcination time is 12-24 hours.

[0093] 22. The method as described in any one of paragraphs 19-22, wherein the roasting is performed after the predetermined roasting temperature is reached at a heating rate of 5-40°C / min.

[0094] 23. The method as described in paragraph 22, wherein the roasting is performed after the predetermined roasting temperature is reached at a heating rate of 10-30°C / min.

[0095] 24. The method of any one of paragraphs 1-23, wherein the acidic solution is selected from one or more inorganic acids or organic acids.

[0096] 25. The method of any one of paragraphs 1-24, wherein the pH of the acidic solution is maintained at 0.5-6.5.

[0097] 26. The method as described in paragraph 25, wherein the pH of the acidic solution is maintained between 1 and 6.

[0098] 27. The method of any one of paragraphs 1-26, wherein the acidic solution is selected from one or a mixture of sulfuric acid, hydrochloric acid, nitric acid, citric acid, aminosulfonic acid, phosphoric acid, formic acid, acetic acid or oxalic acid.

[0099] 28. The method as described in paragraph 27, wherein the acidic solution is selected from oxalic acid, phosphoric acid, aminosulfonic acid, citric acid, or mixtures thereof.

[0100] 29. The method as described in any one of paragraphs 1-28, wherein the acidic solution is an aqueous solution.

[0101] 30. The method as described in any one of paragraphs 1-29, wherein in step (3), the soaking conditions are: soaking time of 1-15 h; soaking temperature of 20-90 °C.

[0102] 31. The method as described in paragraph 30, wherein the soaking time is 3-10 hours.

[0103] 32. The method as described in paragraph 30 or 31, wherein the soaking temperature is preferably 30-70°C.

[0104] 33. The method as described in any one of paragraphs 1-32, wherein, prior to step (3), the calcined filter is cooled to 20-100°C.

[0105] 34. The method as described in paragraph 33, wherein, prior to step (3), the calcined filter is cooled to 40-90°C.

[0106] 35. The method as described in any one of paragraphs 1-34, wherein the ultrasonic cleaning conditions are one or more of the following:

[0107] i. The ultrasonic solvent is deionized water or a water-based cleaning agent;

[0108] ii. The ultrasonic frequency is 5-50kHz, and the ultrasonic power is 0.5-2W.cm -2 ;

[0109] iii. The time is 10-200 minutes;

[0110] iv. The temperature of the ultrasonic solvent is 20-90℃.

[0111] 36. The method described in paragraph 35, wherein the ultrasound time is 20-60 min.

[0112] 37. The method as described in paragraph 35 or 36, wherein the temperature of the ultrasonic solvent is 40-80°C.

[0113] 38. The method as described in any one of paragraphs 1-37, wherein the filter may be purged with steam and / or hot air prior to step (4).

[0114] 39. The method as described in paragraph 38, wherein the purging time is 5-60 min.

[0115] 40. The method as described in any one of paragraphs 1-39, wherein step (1) is carried out using a cleaning apparatus comprising:

[0116] Solvent heating tank;

[0117] Centrifugal pump;

[0118] Filter support frame;

[0119] Filter cleaning tank,

[0120] The filter rinsing tank is connected to the solvent heating tank via a centrifugal pump in a fluid communication manner.

[0121] The present invention will be described below through specific embodiments, but the present invention is not limited thereto.

[0122] Example

[0123] Example 1

[0124] The filter to be regenerated in this embodiment is a sintered metal wire mesh filter. The sintered metal wire mesh filter is made by pressing multiple layers of wire mesh together under special laminations and then vacuum sintering. This filter can be used in the energy and chemical industries. This sintered metal wire mesh filter has a diameter of 60 mm and a length of 1.8 m. It has been operating stably in a Fischer-Tropsch slurry bed reactor for 8000 hours, and at a filtration pressure differential of 50 kPa, the filtration flux increased from 0.625 m³ / h. 3 .m -2 .h -1 Descending to 0.05m 3 .m -2 .h -1 If the filtration pressure differential is increased further, the filtration flux does not change much, indicating that the sintered metal wire mesh filter is severely clogged and needs to be regenerated.

[0125] like Figure 1As shown, the sintered metal wire mesh filter is placed horizontally on the filter support in the filter cleaning tank. The filter support frame is erected in the filter cleaning tank. The sintered metal wire mesh filters are neatly stacked on the filter support frame to prevent them from bumping and being damaged during rinsing and cleaning, and to ensure that the filter is parallel to the flow direction of the cleaning solvent. Light diesel oil solvent is used as the cleaning solvent at a flow rate of 1.8 m / s to clean the inner and outer surfaces of the filter.

[0126] After preheating the cleaning solvent to 150°C in the solvent heating tank, open valve 7 and start centrifugal pump 1 to deliver the cleaning solvent 9 to the filter cleaning tank 2. When the solvent level in the filter cleaning tank 2 exceeds the top filter, open valve 6 to gradually establish solvent circulation. The overflow weir 8 has micropores in its upper part, with a micropore size of 50μm, while the middle and lower parts are not perforated. The overall height of the overflow weir 8 is approximately half the height of the filter cleaning tank 2. Its main function is to ensure that, during stable circulation of the cleaning solvent, it retains as many solid particles as possible within the filter cleaning tank.

[0127] After rinsing the filter with the cleaning solvent for approximately 40 minutes, a significant amount of solid particles will remain in the filter cleaning tank. At this point, centrifugal pump 1, valves 6 and 7 are closed, and the drain valve 4 of the cleaning tank is opened to drain the solvent containing solid particles, thus cleaning the inside of the filter cleaning tank. The solvent released from the drain valve is collected and allowed to settle. The supernatant can be reused after simple filtration and adsorption. Repeating the above cleaning operation three times will remove most of the remaining solid particles. After cleaning with the cleaning solvent, the filter to be processed is calcined in a muffle furnace at 500℃ for 15 hours. Before calcination, the required temperature is reached at a heating rate of 10℃ / min. After high-temperature calcination and cooling, the filter to be processed is removed from the muffle furnace and immersed in a tank containing a preheated oxalic acid aqueous solution at 70℃ for 5 hours, maintaining the pH of the acidic solution at 1.5. After immersion, the filter is removed.

[0128] The filter removed from the oxalic acid solution was steam-purged for 30 minutes to remove any residual acidic solution. Then, the filter was ultrasonically cleaned in deionized water for 40 minutes at 50°C, a frequency of 50 kHz, and a power of 1.5 W. -2 After ultrasonic cleaning, the filter is dried with hot air to obtain a regenerated filter.

[0129] After being regenerated using the above process, the sintered metal mesh filter can achieve a filtration flux of 0.6 m³ / s under a filtration pressure difference of 50 kPa. 3 .m -2 .h -1 above.

[0130] Example 2

[0131] In this embodiment, the filter to be regenerated is a sintered metal wire mesh filter. This sintered metal wire mesh filter has a diameter of 60 mm and a length of 1.8 m. It has been operating stably in a Fischer-Tropsch slurry bed reactor for 8000 hours, and its filtration flux has increased from 0.625 m³ / h under a filtration pressure differential of 50 kPa. 3 .m -2 .h -1 Reduced to 0.05m 3 .m -2 .h -1 the following.

[0132] Except for omitting the acid solution soaking step, the metal sintered wire mesh filter was regenerated using the same method as in Example 1.

[0133] The regenerated sintered metal mesh filter can achieve a filtration flux of 0.35m³ under a filtration pressure difference of 50 kPa. 3 .m -2 .h -1 .

[0134] Example 3

[0135] In this embodiment, the filter to be regenerated is a wedge-shaped mesh filter. The wedge-shaped mesh filter is composed of V-shaped (wedge-shaped) stainless steel wires and stainless steel support bars. This filter can be used in the energy and chemical industry. The wedge-shaped mesh filter has a diameter of 25mm and a length of 1.4m. It has been operating stably for 1000 hours as a feedstock filter in a petrochemical hydrogenation unit, and under a filtration pressure differential of 100KPa, the filtration flux increased from 6.12m³ / h. 3 .m -2 .h -1 Descending to 0.1m 3 .m -2 .h -1 Even if the filtration differential pressure is increased further, the filtration flux does not change much, indicating that the wedge screen filter is severely clogged and needs to be regenerated.

[0136] like Figure 1 As shown, the wedge mesh filter is placed horizontally on the filter support frame in the filter cleaning tank. The filter support frame stands in the filter cleaning tank. The wedge mesh filters are neatly stacked on the filter support frame to prevent them from bumping and being damaged during rinsing and cleaning, and to ensure that the filter is parallel to the flow direction of the cleaning solvent. A flow rate of 1.2 m / s is given, and heavy diesel oil is used as the cleaning solvent to rinse the inner and outer surfaces of the filter.

[0137] After preheating the cleaning solvent to 200℃ in the solvent heating tank, open valve 7 and start centrifugal pump 1 to deliver the cleaning solvent 9 to the filter cleaning tank. When the solvent level in the filter cleaning tank 2 exceeds the top filter, open valve 6 to gradually establish solvent circulation. The overflow weir 8 has micropores in its upper part, with a micropore size of 100μm, while the middle and lower parts are not perforated. The overall height of the overflow weir 8 is approximately 2 / 3 of the height of the filter cleaning tank. Its main function is to ensure that, during stable circulation of the cleaning solvent, it retains as many solid particles as possible within the filter cleaning tank 2.

[0138] After rinsing the filter with the cleaning solvent for approximately 60 minutes, a significant amount of solid particles will remain in the filter cleaning tank. At this point, centrifugal pump 1, valves 6 and 7 are closed, and the drain valve 4 of the cleaning tank is opened to drain the solvent containing solid particles, thus cleaning the inside of the filter cleaning tank. The solvent released from the drain valve is collected, allowed to settle, and the supernatant can be reused after simple filtration and adsorption. This process is repeated three times to remove most of the remaining solid particles. After cleaning with the cleaning solvent, the filter to be cleaned is calcined in a muffle furnace at 650°C for 12 hours. The heating rate is 30°C / min. After calcination and cooling, the filter is removed from the muffle furnace and immersed in a preheated (50°C) aqueous solution of aminosulfonic acid for 3 hours, maintaining the pH of the acidic solution at 6. After immersion, the filter is removed.

[0139] The filter removed from the sulfamic acid solution was steam-purged for 10 minutes to remove any residual acidic solution. Then, the filter was ultrasonically cleaned in deionized water for 40 minutes at 50°C, 40kHz, and 1.2W. -2 After ultrasonic cleaning, the filter is dried with hot air to obtain a regenerated filter.

[0140] After regeneration using the above process, the wedge-shaped mesh filter can achieve a filtration flux of 5.8 m³ / s under a filtration pressure differential of 100 kPa. 3 .m -2 .h -1 above.

[0141] Example 4

[0142] The filter to be recycled in this embodiment is a sintered metal powder filter. Sintered metal powder filters are manufactured by cold isostatic pressing of metal powder, high-temperature vacuum sintering, and welding. This filter can be used in the energy and chemical industry. This sintered metal powder filter has a diameter of 50 mm and a length of 1.5 m. It has been operating stably for 3000 hours as a catalytic cracking slurry filter, with a filtration flux of 0.52 m³ / h at a filtration pressure differential of 150 kPa. 3 .m-2 .h -1 Descended to 0.02m 3 .m - 2 .h -1 Even with further increases in filtration differential pressure, the filtration flux did not change significantly, indicating that the sintered metal powder filter was severely clogged and needed regeneration.

[0143] like Figure 1 As shown, the sintered metal powder filter is placed horizontally on the filter support frame in the filter cleaning tank. The filter support frame is upright in the filter cleaning tank. The sintered metal powder filters are neatly stacked on the filter support frame to prevent them from bumping and being damaged during rinsing and cleaning, and to ensure that the filter is parallel to the flow direction of the cleaning solvent. The inner and outer surfaces of the filter are rinsed with gasoline solvent at a flow rate of 0.8 m / s.

[0144] After preheating the cleaning solvent to 80°C in the solvent heating tank, open valve 7 and start centrifugal pump 1 to deliver the cleaning solvent 9 into the filter cleaning tank. When the solvent level in the filter cleaning tank 2 is about 5cm above the top filter, open valve 6 to gradually establish solvent circulation. The overflow weir 8 has micropores in its upper part, with a micropore size of 180μm, while the middle and lower parts are not perforated. The overall height of the overflow weir 8 is approximately 1 / 3 of the height of the filter cleaning tank. Its main function is to ensure that, during stable circulation of the cleaning solvent, it retains as many solid particles as possible within the filter cleaning tank 2.

[0145] After rinsing the filter with the cleaning solvent for approximately 100 minutes, a significant amount of solid particles will remain in the filter cleaning tank. At this point, centrifugal pump 1, valves 6 and 7 are closed, and the drain valve 4 of the cleaning tank is opened to drain the solvent containing solid particles, thus cleaning the inside of the filter cleaning tank. The solvent released from the drain valve is collected, allowed to settle, and the supernatant can be reused after simple filtration and adsorption. Repeating the above operation 2-3 times will remove most of the remaining solid particles. After cleaning with the cleaning solvent, the filter to be processed is calcined in a muffle furnace at 350℃ for 20 hours. The heating rate is 20℃ / min. After the high-temperature calcination is completed and the filter has cooled down, it is removed from the muffle furnace and immersed in a tank containing a phosphoric acid aqueous solution preheated to 30℃ for 8 hours, maintaining the pH of the acidic solution at 3. After immersion, the filter is removed.

[0146] The filter removed from the phosphoric acid solution was steam-purged for 20 minutes to remove any residual acidic solution. Then, the filter was ultrasonically cleaned in deionized water for 50 minutes at 80°C, 30kHz, and 1W. -2After ultrasonic cleaning, the filter is dried with hot air to obtain a regenerated filter.

[0147] The sintered metal powder filter, after being regenerated using the above process, can achieve a filtration flux of 0.5 m³ / s at a filtration pressure differential of 150 kPa. 3 .m -2 .h -1 above.

[0148] Example 5

[0149] In this embodiment, the filter to be regenerated is a sintered metal powder filter. This sintered metal powder filter has a diameter of 50 mm and a length of 1.5 m. It has been operating stably for 3000 hours as a catalytic cracking slurry filter, and its filtration flux has increased from 0.52 m³ / h at a filtration pressure differential of 150 kPa. 3 .m -2 .h -1 Descended to 0.02m 3 .m -2 .h -1 Even with further increases in filtration differential pressure, the filtration flux did not change significantly, indicating that the sintered metal powder filter was severely clogged and needed regeneration.

[0150] Except for omitting the high-temperature calcination step, the sintered metal powder filter was regenerated using the same method as in Example 4.

[0151] The sintered metal powder filter, after being regenerated using the above process, can achieve a filtration flux of 0.3 m³ / s at a filtration pressure differential of 150 kPa. 3 .m -2 .h -1 .

[0152] Example 6

[0153] In this embodiment, the filter to be regenerated is a metal fiber sintered felt filter. Metal fiber sintered felt filters are made by laying, stacking, and sintering very fine stainless steel fibers at high temperatures. They have extremely high filtration accuracy and dirt-holding capacity, and can be used in the energy and chemical industries. This metal fiber sintered felt filter has a diameter of 200 mm and a length of 0.8 m. It has been operating stably for 3000 hours as a filter in a slag and wax hydrogenation unit, with a filtration flux of 2.538 m³ / h at a filtration pressure differential of 100 kPa. 3 .m -2 .h -1 It dropped to 0.06m 3 .m -2 .h -1 Even with further increases in filtration differential pressure, the filtration flux did not change significantly, indicating that the metal fiber sintered felt filter was severely clogged and needed regeneration.

[0154] like Figure 1 As shown, the metal fiber sintered felt filter is placed horizontally on the filter support frame in the filter cleaning tank. The filter support frame is upright in the filter cleaning tank. The metal fiber sintered felt filters are neatly and fixedly stacked on the filter support frame to prevent them from bumping and being damaged during rinsing and cleaning, and to ensure that the filter is parallel to the flow direction of the cleaning solvent. The inner and outer surfaces of the filter are rinsed with wax oil solvent at a flow rate of 0.5 m / s.

[0155] After preheating the cleaning solvent to 270℃ in the solvent heating tank, open valve 7 and start centrifugal pump 1 to deliver the cleaning solvent 9 to the filter cleaning tank. When the solvent level in the filter cleaning tank 2 exceeds the top filter, open valve 6 to gradually establish solvent circulation. The overflow weir 8 has micropores in its upper part, with a micropore size of 80μm, while the middle and lower parts are not perforated. The overall height of the overflow weir 8 is approximately half the height of the filter cleaning tank. Its main function is to ensure that, during stable circulation of the cleaning solvent, it retains as many solid particles as possible within the filter cleaning tank 2.

[0156] After rinsing the filter with the cleaning solvent for approximately 120 minutes, a significant amount of solid particles will remain in the filter cleaning tank. At this point, centrifugal pump 1, valves 6 and 7 are closed, and the drain valve 4 of the cleaning tank is opened to drain the solvent containing solid particles, thus cleaning the inside of the filter cleaning tank. The solvent released from the drain valve is collected, allowed to settle, and the supernatant can be reused after simple filtration and adsorption. Repeating the above operation once will remove most of the remaining solid particles. After cleaning with the cleaning solvent, the filter to be processed is calcined in a muffle furnace at 400℃ for 30 hours. The heating rate is 35℃ / min. After calcination and cooling, the filter to be processed is removed from the muffle furnace and immersed in a tank containing a preheated citric acid aqueous solution at 90℃ for 9 hours, maintaining the pH of the acidic solution at 5.8. After immersion, the filter is removed.

[0157] The filter removed from the citric acid solution was steam-purged for 50 minutes to remove any residual acidic solution. Then, the filter was ultrasonically cleaned at 30°C, 50kHz, and 1W·cm⁻² for 10 minutes. After ultrasonic cleaning, the filter was dried with hot air to obtain the regenerated filter.

[0158] The metal fiber sintered felt filter, after being regenerated using the above process, can achieve a filtration flux of 2.5 m³ / s at a filtration pressure differential of 100 kPa. 3 .m -2 .h -1 .

[0159] Example 7

[0160] In this embodiment, the filter to be regenerated is a sintered metal wire mesh filter. This sintered metal wire mesh filter has a diameter of 60 mm and a length of 1.8 m. It has been operating stably in a Fischer-Tropsch slurry bed reactor for 8000 hours, and at a filtration pressure differential of 50 kPa, the filtration flux decreased from 0.473 m³ / h. 3 .m -2 .h -1 Descending to 0.05m 3 .m -2 .h -1 the following.

[0161] Except for the soaking step using an oxalic acid aqueous solution with a pH of 4.5, the metal sintered wire mesh filter was regenerated using the same method as in Example 1.

[0162] After being regenerated using the above process, the sintered metal mesh filter can achieve a filtration flux of 0.45m³ under a filtration pressure difference of 50 kPa. 3 .m -2 .h -1 .

[0163] Example 8

[0164] In this embodiment, the filter to be regenerated is a sintered metal wire mesh filter. This sintered metal wire mesh filter has a diameter of 60 mm and a length of 1.8 m. It has been operating stably in a Fischer-Tropsch slurry bed reactor for 8000 hours, and at a filtration pressure differential of 50 kPa, the filtration flux decreased from 0.625 m³ / h. 3 .m -2 .h -1 Descending to 0.05m 3 .m -2 .h -1 the following.

[0165] The method described in Example 1 differs in that: in step (1), the cleaning solvent is gasoline at 60°C and the soaking time is 50 min; in step (3), a phosphoric acid aqueous solution with a pH of 5.5 is used, the soaking temperature is 40°C, and the soaking time is 7 h.

[0166] The metal sintered wire mesh filter, after being regenerated using the above process, can achieve a filtration flux of 0.4 m³ / s under a filtration pressure difference of 50 kPa. 3 .m -2 .h -1 above.

[0167] Example 9

[0168] In this embodiment, the filter to be regenerated is a sintered metal wire mesh filter. This sintered metal wire mesh filter has a diameter of 60 mm and a length of 1.8 m. It has been operating stably in a Fischer-Tropsch slurry bed reactor for 8000 hours, and at a filtration pressure differential of 50 kPa, the filtration flux decreased from 0.625 m³ / h. 3 .m -2 .h -1 Descending to 0.05m 3 .m -2 .h -1 the following.

[0169] Except for the soaking step using an aqueous solution of aminosulfonic acid at pH 2.5, the metal sintered wire mesh filter was regenerated using the same method as in Example 1.

[0170] The metal sintered wire mesh filter, after being regenerated using the above process, can achieve a filtration flux of 0.46 m³ / s under a filtration pressure difference of 50 kPa. 3 .m -2 .h -1 above.

Claims

1. A method for regenerating a filter, the method comprising: (1) washing a filter to be regenerated with a preheated washing solvent to obtain a washed filter; (2) calcining the washed filter to obtain a calcined filter; (3) immersing the calcined filter in an acidic solution; (4) ultrasonically washing the immersed filter in step (3) to obtain a regenerated filter, wherein the filter is a filter used in Fischer-Tropsch synthesis.

2. The method of claim 1, wherein, The filter is a filter used in a slurry bed or a fluidized bed.

3. The method of claim 1, wherein, The filter is selected from one or more of a metal sintered wire mesh filter, a wedge wire filter, a sintered metal powder filter, a metal fiber sintered felt filter, and a porous ceramic filter.

4. The method of any one of claims 1-3, wherein, The washing solvent is a petroleum product with an initial boiling point above 70℃, a Fischer-Tropsch synthesis product, another lipophilic organic compound, or a mixture thereof.

5. The method of any one of claims 1-3, wherein, The washing solvent is one or more of naphtha, gasoline, light diesel oil, heavy diesel oil, and wax oil.

6. The method of any one of claims 1-3, wherein, The washing solvent is one or more of Fischer-Tropsch naphtha, Fischer-Tropsch gasoline, Fischer-Tropsch light diesel oil, Fischer-Tropsch heavy diesel oil, and Fischer-Tropsch wax oil.

7. The method of any one of claims 1-3, wherein, The preheating temperature of the washing solvent is 20-300℃.

8. The method as recited in claim 7, wherein, The preheating temperature of the washing solvent is 30-200℃.

9. The method of any one of claims 1-3, wherein, In step (1), the washing operation is selected from immersion and flushing.

10. The method of claim 9, wherein, The immersion time is 10-120 min.

11. The method of claim 10, wherein, The immersion time is 30-60 min.

12. The method of claim 9, wherein, The flushing conditions are a flow rate of 0.5-2 m / s and a time of 10-120 min.

13. The method of claim 12, wherein, The flushing time is 30-60 min.

14. The method of claim 12 or 13, wherein, The flushing mode is recirculation flushing of the washing solvent.

15. The method of any one of claims 1-3, wherein, Step (1) is performed 1-10 times.

16. The method of any one of claims 1-3, wherein, Before step (1), the method comprises a step of liquid backflushing the filter core with the washing solvent.

17. The method of any one of claims 1-3, wherein, In step (2), the calcination conditions are a temperature of 300-700℃ and a calcination time of 10-40 h.

18. The method of claim 17, wherein, The calcination temperature is 400-650℃.

19. The method of claim 17, wherein, The calcination time is 12-24 h.

20. The method of claim 17, wherein, The calcination is performed after the temperature is raised to the predetermined calcination temperature at a rate of 5-40℃ / min.

21. The method of claim 20, wherein, The calcination is performed after the temperature is raised to the predetermined calcination temperature at a rate of 10-30℃ / min.

22. The method of any one of claims 1-3, wherein, The acidic solution is selected from one or more of an inorganic acid or an organic acid.

23. The method of any one of claims 1-3, wherein, The pH of the acidic solution is maintained at 0.5-6.

5.

24. The method of claim 23, wherein, The pH of the acidic solution is maintained at 1-6.

25. The method of any one of claims 1-3, wherein, The acidic solution is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, citric acid, sulfamic acid, phosphoric acid, formic acid, acetic acid, and oxalic acid.

26. The method of claim 25, wherein, The acidic solution is selected from oxalic acid, phosphoric acid, sulfamic acid, citric acid, or a mixture thereof.

27. The method of any one of claims 1-3, wherein, The acidic solution is an aqueous solution.

28. The method of any one of claims 1-3, wherein, In step (3), the immersion conditions are an immersion time of 1-15 h and an immersion temperature of 20-90℃.

29. The method of claim 28, wherein, The immersion time is 3-10 h.

30. The method of claim 28, wherein, The immersion temperature is 30-70℃.

31. The method of any one of claims 1-3, wherein, Before step (3), the calcined filter is cooled to 20-100℃.

32. The method of claim 31, wherein, Before step (3), the calcined filter is cooled to 40-90℃.

33. The method of any one of claims 1-3, wherein, The ultrasonic cleaning condition is one or more of the following: i. The ultrasonic solvent is deionized water or water-based cleaning agent; ii. ultrasound frequency is 5-50 kHz, ultrasound power is 0.5-2 W.cm -2 ; iii. The time is 10-200 min; iv. The temperature of the ultrasonic solvent is 20-90℃.

34. The method of claim 33, wherein, The ultrasonic time is 20-60 min.

35. The method of claim 33, wherein, The temperature of the ultrasonic solvent is 40-80℃.

36. The method of any one of claims 1-3, wherein, Before step (4), the filter is purged by steam and / or hot air.

37. The method of claim 36, wherein, The purging time is 5-60 min.

38. The method of any one of claims 1-3, wherein, Step (1) is implemented by using a cleaning device, which comprises: a solvent heating tank; a centrifugal pump; a filter support frame; a filter cleaning tank, wherein the filter cleaning tank is connected to the solvent heating tank through the centrifugal pump in a fluid communication manner.

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