Mounting and fixing tool for filter element of catalytic slurry oil filter

Abstract

The utility model relates to a catalytic slurry oil filter element mounting and fixing tool, which belongs to the field of petrochemical engineering, and comprises an element and a tube plate, after a threaded mounting section of the filter element is inserted into the tube plate for mounting, a short-circuit connecting ring is additionally arranged between the mounting section of the filter element and the tube plate, and the filter element is mounted on the tube plate. The filter element is sealed and fixed on the tube plate by the short-circuit connecting ring in a welding manner; a bottom fixed connecting plate is additionally arranged at the bottom of the filter element by taking a row of a plurality of filter elements as a filter element short-circuit unit and is used for enhancing the overall strength of the filter element; the bottom fixed connecting plate is a long-strip-shaped steel plate, mounting holes are evenly formed in the long-strip-shaped steel plate according to the outer diameter of the extending section of the bottom of the filter element, the filter element is sleeved with the mounting holes, and a limiting bolt is transversely arranged at the tail end of the extending section of the bottom of the filter element so as to prevent the bottom fixed connecting plate from sliding upwards. According to the oil slurry filter online cleaning tool, filter offline blowback pressure and filter offline pressure difference are adjusted in an assisted mode, online cleaning is reasonably carried out, and the operation cycle of an oil slurry filter can be effectively prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of petrochemical industry and relates to a catalytic oil slurry filter element installation and fixing tool, which is used for realizing the long-cycle operation of the oil slurry filter of a catalytic cracking device. Background Art

[0002] As a by-product of the catalytic cracking unit, the slurry oil is filtered by the slurry oil filtration system and sent to the downstream device for further processing and utilization. The slurry oil filter is the main purification and separation equipment of the slurry oil filtration system, and adopts high-temperature desolidification technology to reduce the solid content in the slurry oil. The core element of the slurry oil filter is a non-homogeneous metal powder sintered filter element with a filtration accuracy of 0.5um. When the hot slurry oil passes through the filter element, the slurry oil liquid can pass through the filter element, and the clean slurry oil (filtrate) enters the downstream device, while the solid catalyst particles are trapped on the inner surface of the filter element. The filtered solid catalyst filter cake is discharged to the filter cake receiving tank by dry gas backwashing. During the slag discharge process, the rapid pressure release and the reverse flow of the recycled oil can quickly peel off the solids on the inner surface of the filter element, and all the media inside the filter can flow out of the filter through the slag discharge valve.

[0003] The filter element of the current oil slurry filter is tightened to the tube sheet with a gasket seal plus a washer and double nuts (see Figure 1 ), the bottom of the filter element is not fixed with additional measures (see Figure 2 ). During the actual operation, the solid content of the filtered liquid after the filter was frequently exceeded the standard (>500ppm). When the filter was stopped for maintenance, it was found that the gasket seal between the filter element and the tube sheet failed and the filter element was broken, resulting in leakage. Through repeated maintenance, it was found that there were some unreasonable designs in the current filter element installation and fixation. For example, when the filter element and the tube sheet are sealed with gaskets, the filter element is easily subjected to force vibration during the backwashing process without taking corresponding fixing measures, resulting in the failure of the seal at the connection between the filter element and the tube sheet or cracks or even breaks in the filter element, resulting in frequent failure of the solid content of the oil slurry filtrate, which in turn affects the long-term operation of the oil slurry filter.

[0004] In short, due to the characteristics of high density, high viscosity, high freezing point and carrying of solid catalyst fine powder, the combined effect of catalyst, colloid and asphalt in the oil slurry during the operation of the filter causes filter element blockage, frequent leakage at the seal between the filter element and the tube sheet caused by frequent online and offline operations, cracks in the filter element and even breakage, etc., resulting in poor stable and reliable operation of the oil slurry filtration system. At present, it needs major repairs every 2 to 4 months on average because the solid content of the filtrate does not meet the indicators.

[0005] CN212548619U discloses a threaded pipe head of a filter element of an oil slurry filter, comprising a filter housing, a filter tube, a filter tube sheet, a high-temperature sealant, a filter tube sheet sealing pad, a top oil slurry outlet pipe and a bottom oil slurry inlet pipe, the filter tube is vertically mounted on the filter tube sheet, and the surface of the end of the filter tube is bonded with a high-temperature sealant. The utility model optimizes the high-temperature sealant, and after the NPT cone pipe threaded connection on the upper part of the filter tube is sealed with the high-temperature sealant, the oil slurry before the filter can be effectively prevented from leaking through the gap of the pipe head threaded connection to the oil slurry after the filter, and the threaded connection of the filter tube is efficiently matched and sealed, and the use effect is good, and the filter tubes can be conveniently removed from the filter tube sheet one by one for thorough cleaning, and the filtering function of the filter tube can be restored. However, the threaded pipe head of the filter element of the utility model of the oil slurry filter is mainly set with the high-temperature sealant sealing technology at the NPT cone pipe threaded connection on the upper part of the filter tube, which can effectively prevent the oil slurry before the filter from leaking through the gap of the pipe head threaded connection to the oil slurry after the filter, and cannot effectively solve the problem that the operation cycle of the ground oil slurry filter is short and frequent maintenance is required. Utility Model Content

[0006] In order to solve the problems of frequent leakage at the seal between the filter element and the tube sheet of the catalytic oil slurry filter, cracks in the filter element and even breakage, which affect the long-term operation, and to reduce the frequency of filter maintenance and extend the service life of the filter element, the present invention proposes a method for solving the long-term operation of the oil slurry filter from the perspectives of the filter element installation and fixing tooling and the operating conditions in the filter production process. While ensuring that the solid content index of the filtrate after filtration is qualified (≤500ppm), the operation cycle of the oil slurry filter is effectively improved.

[0007] The utility model adopts the following technical solutions to solve:

[0008] According to a first aspect of the utility model, the utility model provides a catalytic oil slurry filter element installation and fixing tool, comprising:

[0009] After the threaded installation section of the filter element is inserted into the tube sheet for installation, a short-circuit connection ring is installed between the installation section of the filter element and the tube sheet. The short-circuit connection ring seals and fixes the filter element to the tube sheet by welding, replacing the original gasket and nut installation and fixing method, and completely solving the problem of frequent leakage caused by the gasket sealing between the filter element and the tube sheet. At the same time, the short-circuit connection ring between the filter element and the tube sheet can effectively increase the number of times the filter element can be repeatedly welded after being removed.

[0010] A bottom fixed connecting plate is installed at the bottom of the filter element (unwelded end) in a row of 5 to 8 filter elements as a group to enhance the overall strength of the filter element and control the force swing amplitude of the tail of the filter element within ±2mm. The bottom fixed connecting plate is a long stainless steel plate. Mounting holes are evenly opened on the long stainless steel plate according to the outer diameter of the bottom extension section of the filter element. The filter element is inserted into the mounting holes, and a limit bolt is horizontally set at the end of the bottom extension section of the filter element to prevent the bottom fixed connecting plate from slipping upward. A bottom fixed connecting plate is installed at the bottom of the filter element (unwelded end) in a row of 5 to 8 filter elements as a group to enhance the overall strength of the filter element and control the force swing amplitude of the tail of the filter element within ±2mm. Specifically, according to the embodiment of the present invention, 5 to 8 filter elements of each filter element short-circuit unit can be equipped with a bottom fixed connecting plate to form a first filter element unit (5 elements), a second filter element unit (6 elements), a third filter element unit (7 elements) and a fourth filter element unit (8 elements), and the units are filled and assembled into a circle in a horizontal row in a geometric puzzle manner. To further increase the connection strength, the units in adjacent horizontal rows use different types of filter element units, so that the joints between the units in each row are staggered with the joints in adjacent rows. Such a filter element installation and fixing device can reduce the force vibration of the filter element during the backwashing process, and prevent the filter element from being fatigued and fractured due to excessive vibration amplitude; on the other hand, while reducing the force vibration of the filter element, it is also convenient to remove the filter residue (filter cake) on the surface of the filter element during the backwashing process.

[0011] According to the second aspect of the utility model, the utility model provides an operating process method based on a catalytic oil slurry filter element installation fixing tool, comprising:

[0012] (1) Adjust the back-blowing pressure of the filter offline, and strictly control the back-blowing pressure to 0.65~0.7MPa. The key to the back-blowing operation is to control the back-blowing pressure. If the back-blowing pressure is too low, the filter cake stored on the surface area of ​​the filter element cannot be effectively removed; if the back-blowing pressure is too high, the filter element will be subjected to a greater impact during the back-blowing process, which can easily cause the filter element to break. When the oil slurry filter is offline, the filter residue is back-blown to the filter cake receiving tank. First, the exhaust valve of the filter cake receiving tank must be opened to prevent pressure build-up during back-blowing. After the exhaust valve is opened, the filter cake receiving tank is connected to the distillation tower, and the back pressure is the pressure of the distillation tower. The operating pressure of the distillation tower is basically 0.15~0.20MPa. The back-blowing effect is determined by a certain pressure drop. According to operating experience and experimental data, the filter element is not easy to break when the pressure drop is controlled at 0.5MPa. Therefore, the back-blowing pressure must be strictly controlled at 0.65~0.7Mpa;

[0013] (2) Set the filter offline pressure differential to no more than 250KPa and the offline time interval to less than 12 hours, slow down the filter pressure differential increase rate, and increase the filter element service life. The filter pressure differential is the most critical parameter for the operation of the oil slurry filter. The reason why the oil slurry filters in most refineries have short operating cycles is that the filter elements are seriously clogged and the filter pressure differential rises too quickly, resulting in frequent offline operations and inability to maintain operation. By setting an appropriate filter offline pressure differential (no more than 250KPa) and time (offline time interval less than 12 hours), the offline backwashing effect can be guaranteed, and the filter cake on the surface of the filter element can be effectively removed (if the filter offline pressure differential is too high or the offline time is too long, the filter cake on the surface of the filter element will thicken, affecting the offline backwashing effect and causing serious clogging of the filter element), thereby extending the filter element service life;

[0014] (3) Perform online cleaning properly. If the filter element cannot recover the initial pressure difference after offline backflushing, perform online cleaning to minimize the frequency of offline maintenance and cleaning of the filter. Fill the offline filter back into the refinery and soak it for 12 hours, then backflush it to completely remove the blockage. Observe the initial pressure difference when the filter is put into use after offline backflushing. When the initial pressure difference rises, it means that the filter element begins to become clogged. Online cleaning should be performed in time to reduce the frequency of offline maintenance and cleaning of the filter due to serious blockage of the filter element.

[0015] The beneficial effects of the utility model are:

[0016] The utility model changes the sealing method between the filter element and the tube sheet of the oil slurry filter from gasket sealing to welding with a short-circuit connecting ring, which completely solves the problem of frequent leakage when the gasket seal is used between the filter element and the tube sheet; by adding a bottom fixed connecting plate at the tail of the filter element, the overall strength of the filter element is enhanced, and the force swing amplitude of the tail of the filter element is controlled within ±2mm, thereby improving the service life of the filter element. The tooling of the utility model greatly reduces the maintenance frequency of the filter by further cooperating with the filter operation process method, prolongs the service life of the filter element, and effectively improves the operation cycle of the oil slurry filter while ensuring that the solid content index of the filtrate after filtration of the filter is qualified (≤500ppm), which has significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : Schematic diagram of the filter element of the oil slurry filter being tightened to the tube sheet using a gasket seal, a washer and double nuts.

[0018] Figure 2 : Schematic diagram of no fixing measures installed at the bottom of the filter element.

[0019] Figure 3 : Schematic diagram of the filter element and the tube sheet being fixed by a short-circuit connecting ring and welding.

[0020] Figure 4: Schematic diagram of a bottom fixed connecting plate installed at the bottom of the filter element of the present invention, wherein a bottom fixed connecting plate is installed at the bottom of the filter element in a row of 5 to 8 filter elements as a group.

[0021] Figure 5 : Figure 4 Section view along AA.

[0022] In the figure:

[0023] 1—filter element; 2—tube sheet; 30—gasket, 31—washer, 32—nut, 33—short-circuit connecting ring, 34—bottom fixed connecting plate; 4—filter element short-circuit unit, 41—first type of filter element unit, 42—second type of filter element unit, 43—third type of filter element unit, 44—fourth type of filter element unit; 5—limit bolt. DETAILED DESCRIPTION

[0024] Example 1

[0025] A catalytic oil slurry filter element installation and fixing tool, such as Figure 3 As shown, it includes a core 1 and a tube sheet 2. After the threaded mounting section of the filter element 1 is inserted into the tube sheet 2 for installation, a short-circuit connecting ring 33 is installed between the mounting section of the filter element 1 and the tube sheet 2. The short-circuit connecting ring 33 seals and fixes the filter element 1 on the tube sheet 2 by welding, replacing the original gasket 31 and nut 32 installation and fixing method, and completely solves the problem of frequent leakage caused by the gasket 31 used to seal the filter element 1 and the tube sheet 2. At the same time, the short-circuit connecting ring 33 between the filter element 1 and the tube sheet 2 can effectively increase the number of times the filter element is repeatedly welded after being removed.

[0026] like Figure 4 , Figure 5 As shown, a bottom fixing connecting plate 34 is installed at the bottom of the filter element 1 (the unwelded end) with 5 to 8 filter elements in a row as a group to enhance the overall strength of the filter element 1 and control the force swing amplitude of the tail of the filter element 1 within ±2mm. The bottom fixing connecting plate 34 is a long stainless steel plate, and mounting holes are evenly opened on the long stainless steel plate according to the outer diameter of the bottom extension section of the filter element. The filter element 1 is inserted into the mounting hole, and a limit bolt 5 is horizontally arranged at the end of the bottom extension section of the filter element to prevent the bottom fixing connecting plate 34 from slipping upward.

[0027] Specifically, 5 to 8 filter elements in each filter element short-circuit unit are equipped with a bottom fixed connecting plate to form a first filter element unit 41 (5 elements), a second filter element unit 42 (6 elements), a third filter element unit 43 (7 elements) and a fourth filter element unit 44 (8 elements), and they are filled and assembled into a circle in the center of horizontal rows in a geometric puzzle manner. To further increase the connection strength, units in adjacent horizontal rows use different filter element unit types, so that the seams between units in each row are staggered with the seams of adjacent rows.

[0028] In this embodiment, the way to splice into a circle from bottom to top and from left to right is:

[0029] The fourth type of filter element unit 44 (8 in total),

[0030] The first filter element unit 41 - the second filter element unit 42 (11 in total),

[0031] The third type of filter element unit 43 - the third type of filter element unit 43 (a total of 14),

[0032] The first filter element unit 41 - the first filter element unit 41 - the second filter element unit 42 (a total of 16),

[0033] The second filter element unit 42 - the second filter element unit 42 - the second filter element unit 42 (18 in total);

[0034] …

[0035] The fourth type of filter element unit 44 - the fourth type of filter element unit 44 - the fourth type of filter element unit 44 (a total of 24),

[0036] On the right, the fourth filter element unit 44 - the fourth filter element unit 44 - the fourth filter element unit 44 (a total of 24),

[0037] On the left, the fourth filter element unit 44 - the fourth filter element unit 44 - the fourth filter element unit 44 (24 in total);

[0038] …

[0039] The second filter element unit 42 - the second filter element unit 42 - the second filter element unit 42 (a total of 18),

[0040] The first filter element unit 41 - the first filter element unit 41 - the second filter element unit 42 (a total of 16),

[0041] The third type of filter element unit 43 - the third type of filter element unit 43 (a total of 14),

[0042] The first filter element unit 41 - the second filter element unit 42 (11 in total),

[0043] The fourth type of filter element unit 44 (8 in total).

[0044] The filter element installation and fixing device of the utility model can, on the one hand, reduce the force vibration of the filter element during the backwashing process, and prevent the filter element from fatigue fracture due to excessive vibration amplitude; on the other hand, while reducing the force vibration of the filter element, it is also convenient to remove the filter residue (filter cake) stored on the outer surface of the filter element during the backwashing process.

[0045] Example 2

[0046] The filter operation process method based on the catalytic oil slurry filter element installation fixing tooling includes:

[0047] (1) After the short-circuit connection ring 33 is installed and welded to the tube sheet 2, the filter element 1 is installed on the tube sheet 2, and the connection between the filter element 1 and the short-circuit connection ring 33 is fixed and sealed by welding (see Figure 3 ); at the same time, a bottom fixing connecting plate 34 is installed at the bottom of the filter element 1 (the unwelded end) with 5 to 8 filter elements in a row as a group (see Figure 4 ) to enhance the overall strength of the filter element. On the one hand, it can reduce the force vibration of the filter element during the backwashing process; on the other hand, while reducing the force vibration of the filter element, it is also convenient to remove the filter residue (filter cake) on the surface of the filter element during the backwashing process. After the transformation, the qualified rate of solid content of the oil slurry filtrate is 100%;

[0048] (2) Adjust the back-blowing pressure of the filter offline, and strictly control the back-blowing pressure to 0.65~0.7MPa. The key to the back-blowing operation is to control the back-blowing pressure. If the back-blowing pressure is too low, the filter cake stored on the surface area of ​​the filter element cannot be effectively removed; if the back-blowing pressure is too high, the filter element will be hit hard during the back-blowing process, which can easily cause the filter element to break. When the oil slurry filter is offline, the filter residue is back-blown to the filter cake receiving tank. First, the exhaust valve of the filter cake receiving tank must be opened to prevent pressure build-up during back-blowing. After the exhaust valve is opened, the filter cake receiving tank is connected to the distillation tower, and the back pressure is the pressure of the distillation tower. The operating pressure of the distillation tower is basically 0.15~0.20MPa. The back-blowing effect is determined by a certain pressure drop. According to operating experience and experimental data, the filter element is not easy to break when the pressure drop is controlled at 0.5MPa. Therefore, the back-blowing pressure must be strictly controlled at 0.65~0.7MPa.

[0049] (3) Set the filter offline pressure difference to no more than 250KPa and the offline time interval to less than 12 hours, slow down the filter pressure difference increase rate, and increase the filter element service life. The filter pressure difference is the most critical parameter for the operation of the oil slurry filter. The reason why the operation cycle of most refinery oil slurry filters is short is that the filter element is seriously clogged and the filter pressure difference rises too quickly, resulting in frequent offline and unable to maintain operation. By setting the appropriate filter offline pressure difference (no more than 250KPa) and time (offline time interval less than 12 hours), the offline backwashing effect can be guaranteed, and the filter cake on the surface of the filter element can be effectively removed (if the filter offline pressure difference is too high or the offline time is too long, the filter cake on the surface of the filter element will thicken, affecting the offline backwashing effect and causing serious clogging of the filter element), and extending the filter element service life.

[0050] (4) Perform online cleaning properly. If the filter element cannot recover to the initial pressure difference after offline backflushing, perform online cleaning to minimize the frequency of offline maintenance and cleaning of the filter. Fill the offline filter back into the refinery and soak it for 12 hours, then backflushed it to completely remove the blockage. Observe the initial pressure difference when the filter is put into use after offline backflushing. When the initial pressure difference rises, it means that the filter element begins to become clogged. Online cleaning should be performed in time to avoid the online cleaning effect becoming worse after the filter element is seriously clogged. Fill the offline filter back into the refinery and soak it for 12 hours, then backflushed it to completely remove the blockage. The filtration efficiency can reach 97.1% after use, reducing the frequency of offline maintenance and cleaning of the filter due to serious filter element clogging.

[0051] After the transformation, the filter maintenance and spare parts procurement costs can be saved by about 2 million yuan per year, avoiding the shutdown of the oil slurry system due to frequent filter maintenance and the direct dumping of a large amount of catalytic oil slurry during the maintenance period, increasing the output of oil slurry filtrate, and bringing huge production economic benefits to the enterprise. The oil slurry filtration system processes about 200,000 tons of oil slurry per year. The price of filtrate as coking raw material is about 1,578 yuan per ton, and the direct takeaway price of catalytic oil slurry is about 1,218 yuan per ton (refer to the oil slurry price of Quanzhou Petrochemical). According to this calculation, the economic benefits of catalytic oil slurry after being treated by the oil slurry filtration system will increase by about 72 million yuan per year.

Claims

1. A catalytic oil slurry filter element installation and fixing tool, comprising a filter element (1) and a tube sheet (2), characterized in that: The threaded mounting section of the filter element (1) is inserted into the tube sheet (2), and a short-circuit connecting ring (33) is installed between the mounting section of the filter element (1) and the tube sheet (2), wherein the short-circuit connecting ring (33) seals and fixes the filter element (1) to the tube sheet (2) by welding; A bottom fixing connecting plate (34) is installed at the bottom of the filter element (1) to form a filter element short-circuit unit composed of a row of a plurality of filter elements (1), so as to enhance the strength of fixing the filter element (1) on the tube sheet (2); The bottom fixed connecting plate (34) is a long steel plate, on which mounting holes are evenly arranged according to the outer diameter of the bottom extension section of the filter element (1), the filter element (1) is inserted into the mounting holes, and a limiting bolt (5) is transversely arranged at the end of the bottom extension section of the filter element (1) to prevent the bottom fixed connecting plate (34) from sliding upward.

2. The catalytic oil slurry filter element installation and fixing tool according to claim 1 is characterized in that: Each filter element short-circuit unit comprises 5 to 8 filter elements (1).

3. The catalytic oil slurry filter element installation and fixing tool according to claim 2 is characterized in that: Each filter element short-circuit unit comprises a first filter element unit (41) of five filter elements (1), a second filter element unit (42) of six filter elements (1), a third filter element unit (43) of seven filter elements (1), and a fourth filter element unit (44) of eight filter elements (1), and the filter element short-circuit units are assembled into a nearly circular shape in a horizontal row and centered filling manner in a geometric jigsaw manner.

4. The catalytic oil slurry filter element installation and fixing tool according to claim 3 is characterized in that: The filter element short-circuit units in adjacent horizontal rows adopt different filter element unit types, so that the joints between the filter element short-circuit units in each row and the joints between the filter element short-circuit units in adjacent rows are staggered.

5. The catalytic oil slurry filter element installation and fixing tool according to any one of claims 1 to 4, characterized in that: The bottom fixed connecting plate (34) is used to control the force swing amplitude of the tail of the filter element (1) to within 2 mm.

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