Sand-raking-free maintenance device and method in air separation plant cold box

Abstract

The invention discloses a sand-raking-free maintenance device and method in an air separation plant cold box, the sand-raking-free maintenance device comprises a fixed positioning guide sleeve, a rotary cutting sand blocking device and a push type guide sleeve, and the fixed positioning guide sleeve is welded to the outer side of a cold box plate; the rotary cutting sand plugging device comprises a fixing support, a cutter head and a driving mechanism, and at least one pair of rhombic cutters is arranged at the front end of the cutter head. And the front end port of the push type guide sleeve is matched with the outer surface of the tower or the condensing evaporator barrel in shape. Maintenance can be completed without cleaning all pearlife, a large amount of manpower, financial resources and time cost are saved, and operation risks and pollution to the environment in the conventional maintenance process are avoided.

Description

Technical Field

[0001] This invention relates to the field of air separation equipment maintenance technology, specifically to a sand-free maintenance device and method for the cold box of an air separation equipment. Background Technology

[0002] In recent years, with the continuous expansion of my country's coal chemical industry, the demand for oxygen in air separation equipment has also been increasing. The scale of extra-large air separation equipment has risen from 70,000 and 80,000 kilowatts to 100,000, 110,000, 120,000 kilowatts and above. Meanwhile, newly developed extra-large pressure vessels and large-size pipelines are constantly being introduced by various design institutes. However, some new products, such as pressure towers and condenser-evaporators, have encountered problems during actual operation due to improper design, manufacturing, installation, and operation. After analyzing and discussing to identify the problem points, local modifications to the internal structure of the relevant containers are necessary. However, the air separation cold box is a concealed space filled with insulating perlite. Conventional modifications to the cold box require a significant amount of manpower, material resources, financial resources, and time to completely clean the perlite, posing safety risks during the operation and causing environmental pollution from the large amount of dust. Therefore, this invention patent proposes an efficient and convenient non-sand-removal internal inspection and maintenance process device and method. Summary of the Invention

[0003] The purpose of this invention is to provide an efficient and convenient maintenance device and method for the cold box of an air separation unit without removing sand, so as to solve the problems existing in conventional cold box renovation.

[0004] To address the shortcomings of existing technologies, this invention provides the following technical solution: a sand-free maintenance device for a cold box in an air separation unit, wherein a tower or condenser-evaporator cylinder is located in the central area of ​​the cold box, and the area between the tower or condenser-evaporator cylinder and the cold box plate is filled with perlite; the sand-free maintenance device includes a fixed positioning guide sleeve, a rotary cutting and sand-blocking device, and a propulsion guide sleeve, wherein:

[0005] A fixed positioning guide sleeve is welded to the outside of the cold box plate, and the surface of the fixed positioning guide sleeve is provided with several locking bolts along the circumferential direction;

[0006] The rotary cutting and sand-blocking device includes a fixed bracket, a cutter head, and a drive mechanism. The front end of the cutter head is provided with at least a pair of diamond-shaped cutters. The drive mechanism can drive the cutter head to rotate, thereby cutting circular holes in the cold box plate through the diamond-shaped cutters.

[0007] The front end of the push-type guide sleeve matches the shape of the outer surface of the tower or condenser-evaporator shell. The push-type guide sleeve can be inserted into the circular hole along the gap between the fixed positioning guide sleeve and the rotary cutting and sand-blocking device until the end of the push-type guide sleeve is in contact with the tower or condenser-evaporator shell.

[0008] When the push-type guide sleeve contacts and pushes the diamond cutter during insertion, the diamond cutter can rotate inward.

[0009] The diameter of the cut-off circular cold box plate is smaller than the inner diameter of the push-type guide sleeve.

[0010] Preferably, a positioning drill bit is provided at the center of the cutter head.

[0011] Furthermore, the positioning drill bit is equipped with an anti-detachment spring that can automatically spring outward.

[0012] Preferably, a blade holder is fixedly provided on both sides of the blade disc, and the diamond-shaped cutter is fixed to the blade holder by bolts or reverse thread bolts, so that the diamond-shaped cutter can rotate inward under the push of the push-type guide sleeve from the outside to the inside.

[0013] Preferably, the drive mechanism is detachably mounted on the rear side of the fixed bracket, and the cutter head is connected to the drive mechanism via a power linkage.

[0014] Furthermore, the drive mechanism includes a motor bracket and a motor and a reducer fixedly mounted on the motor bracket. The motor bracket is detachably connected to the rear side of the fixed bracket, and the output end of the reducer is connected to the power linkage.

[0015] Preferably, a sand baffle is provided on the front side of the cutter head.

[0016] Preferably, the push-type guide sleeve includes a general part and a special part. The cut-off circular cold box plate is welded to the boundary between the general part and the special part, and the cut circular hole is filled after the repair is completed.

[0017] Preferably, the front end of the push-type guide sleeve is provided with a washer along the port.

[0018] The above-mentioned non-sand-removal maintenance device for the cold box of an air separation unit includes the following steps during maintenance:

[0019] Step 1, Cutting the cold box panels:

[0020] 1-1. First, weld the fixed positioning guide sleeve to the cold box plate where the hole needs to be made;

[0021] 1-2. Install a rotary cutting and sand-blocking device inside the fixed guide sleeve that has been welded in place;

[0022] 1-3. A circular hole is cut into the cold box plate using a diamond cutter. The size of the circular hole matches the outer diameter of the push-type guide sleeve. The diameter of the cut circular cold box plate is slightly smaller than the inner diameter of the push-type guide sleeve.

[0023] Step 2: Insert the push-type guide sleeve:

[0024] 2-1. Remove the drive mechanism of the rotary cutting and sand-blocking device;

[0025] 2-2. Insert the push-type guide sleeve into the gap between the fixed positioning guide sleeve and the rotary cutting and sand-blocking device until the front end of the push-type guide sleeve is in contact with the tower or condenser-evaporator shell. During the insertion process, the push-type guide sleeve will push the diamond cutter to rotate and make way.

[0026] 2-3. Secure the push-type guide sleeve with locking bolts;

[0027] Step 3, Sand Removal:

[0028] 3-1. Remove the rotary cutting and sand-blocking device;

[0029] 3-2. Clean the perlite inside the fixed positioning guide sleeve and the push-type guide sleeve;

[0030] Step 4: Inspect and seal the cold box panels:

[0031] 4-1. Construction personnel and tools enter the propulsion guide sleeve, and the cutting equipment manhole is used for container maintenance.

[0032] 4-2. After the maintenance is completed, the cut-off circular cold box plate will be partially repaired and then welded to the boundary between the general part and the special part of the push-type guide sleeve, so that the general part and the special part are sealed and isolated.

[0033] 4-3. Loosen the locking bolts and pull the push-type guide sleeve outward. When the circular cold box panel overlaps with the cold box panel, first cut and remove the fixed positioning guide sleeve from the cold box panel. Then weld the special part of the push-type guide sleeve onto the circular hole of the cold box panel. Finally, cut and remove the general part of the push-type guide sleeve from the cold box panel. The cold box panel is then restored to its closed state, and the construction is complete.

[0034] Compared with the prior art, the advantages of this invention are as follows:

[0035] This invention uses a fixed positioning guide sleeve to position and guide the subsequent rotary cutting and sand-blocking device and the push-type guide sleeve. The rotary cutting and sand-blocking device then cuts the cold box plate, and the push-type guide sleeve is inserted to isolate a space for maintenance. Maintenance can be completed without cleaning all the perlite, saving a lot of manpower, financial resources and time costs, and avoiding the operational risks and environmental pollution of conventional maintenance processes.

[0036] In the final sealing step, this invention reuses the cut-off circular cold box plate as the sealing material, further saving costs.

[0037] In a preferred embodiment of the present invention, a positioning drill bit with an anti-drop function is provided at the center of the cutter head, which on the one hand positions the cutting position, and on the other hand prevents the cut circular cold box plate from falling off.

[0038] In a preferred embodiment of the present invention, the diamond-shaped cutter is fixed to the cutter holder by bolts or reverse threaded bolts, so that the diamond-shaped cutter can rotate inward under the push of the push-type guide sleeve from the outside to the inside, thereby giving way to the push of the push-type guide sleeve. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0040] Figure 2 This is a schematic diagram of the insertion and propulsion guide sleeve of the present invention.

[0041] Figure 3 This is a schematic diagram of the sand removal process of the present invention.

[0042] Figure 4 This is a schematic diagram of the cold box panel of the present invention when it is closed. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments.

[0044] A non-sand-removal maintenance device for the cold box of an air separation unit, referring to Figure 1-4 The central area of ​​the cold box is equipped with a tower or condenser-evaporator cylinder 100, and the area between the tower or condenser-evaporator cylinder 100 and the cold box plate 200 is filled with perlite 300. The sand-free maintenance device includes a fixed positioning guide sleeve 1, a rotary cutting and sand-blocking device 2, and a push-type guide sleeve 3. After positioning by the fixed positioning guide sleeve 1, the rotary cutting and sand-blocking device 2 cuts a circular hole in the cold box plate 200. Then, the push-type guide sleeve 3 is inserted to isolate a maintenance area for maintenance. After maintenance is completed, the cold box plate needs to be sealed.

[0045] The fixed positioning guide sleeve 1 is cylindrical and is welded to the outside of the cold box plate during construction, mainly serving as a guide and positioning element. Four locking bolts 1.1 are evenly arranged around the circumference at appropriate positions on the fixed positioning guide sleeve 1, passing through the cylinder body, to lock and fix the subsequent equipment.

[0046] The rotary cutting and sand-blocking device 2 includes a fixed bracket 2.7, a cutter head 2.10, and a drive mechanism. The drive mechanism is detachably mounted on the rear side of the fixed bracket 2.7, and the cutter head 2.10 is rotatably mounted on the front side of the fixed bracket. The cutter head is connected to the drive mechanism via a power linkage 2.4, thereby driving the cutter head to rotate through the drive mechanism.

[0047] Specifically, the drive mechanism includes a motor bracket 2.2 detachably mounted on a fixed bracket, a motor 2.1 fixedly mounted on the motor bracket, and a reducer 2.3. The output end of the motor is connected to the power linkage 2.4 after being reduced in speed by the reducer.

[0048] A positioning drill bit 2.9 is provided at the center of the cutter head for positioning before cutting. In this embodiment, the positioning drill bit is provided with a set of anti-drop springs that can automatically pop outward. Specifically, the anti-drop springs are embedded and rotatably set at the relative center of the drill bit, and have a retaining spring inside. During the drilling process, the anti-drop springs are in a closed state, and the shape of the drill bit is no different from that of an ordinary drill bit. When the drill bit passes through the cold box plate, the anti-drop springs pop outward without external force constraint, thereby preventing the cut circular cold box plate from falling off.

[0049] The cutter head is fixedly provided with a cutter holder 2.6 on each side edge. A diamond cutter 2.5 is installed on the cutter holder. The diamond cutter is fixed to the cutter holder by bolts. The diamond cutter can rotate inward to avoid collision when it contacts and is pushed during the insertion of the push-type guide sleeve. Therefore, if necessary, the diamond cutter can be fixed with a reverse thread bolt 2.11.

[0050] The structure of the fixed bracket 2.7 is mainly composed of a circular top plate and a cylindrical side plate. The end of the cylindrical side plate has an inclination angle and is fitted with the rear side of the tool holder 2.6 with a clearance. The rear edge of the tool disc 2.10 is provided with an annular flange, which is fitted with the inner wall of the cylindrical side plate with a clearance.

[0051] In this embodiment, a sand baffle 2.8 is also provided on the front side of the cutter head to prevent the perlite from leaking out during operation.

[0052] The front end of the push-type guide sleeve 3 matches the shape of the outer surface of the tower or condenser-evaporator cylinder 100, and a gasket 3.3 with a thickness of about 1-2mm is provided on the inner side of the port, so that the push-type guide sleeve is inserted into the circular hole along the gap between the fixed positioning guide sleeve 1 and the rotary cutting and sand blocking device 2 until the port of the push-type guide sleeve 3 is in contact with the tower or condenser-evaporator cylinder 100, thereby isolating an area for maintenance after insertion.

[0053] In this embodiment, the propulsion guide sleeve includes a general-purpose part 3.1 and a special-purpose part 3.2. The cut-off circular cold box plate 4 is welded to the boundary between the general-purpose part and the special-purpose part. After maintenance, the cut circular hole is filled. The general-purpose part can be reused multiple times. The special-purpose part is a one-time installation and will remain inside the cold box after maintenance. Since the diameter and amplitude of the towers in different projects are different, the special-purpose part is designed specifically according to different situations.

[0054] In the above structure, the cut circular hole is approximately equal to the inner diameter of the fixed positioning guide sleeve 1 and matches the outer diameter of the push-type guide sleeve 3; the diameter of the cut-off circular cold box plate 4 is slightly smaller than the inner diameter of the push-type guide sleeve 3, and the maximum size of the fixed bracket of the rotary cutting and sand-blocking device 2 is slightly smaller than the inner diameter of the push-type guide sleeve 3, so that the rotary cutting and sand-blocking device 2 and the cut-off circular cold box plate 4 can be smoothly removed from the push-type guide sleeve 3.

[0055] In specific implementation, this invention includes the following steps:

[0056] Step 1: Cutting the cold box sheet (refer to...) Figure 1 ):

[0057] 1-1. First, weld the fixed positioning guide sleeve 1 to the cold box plate where the hole needs to be opened;

[0058] 1-2. Install the fixed bracket and cutter head of the rotary cutting sand blocking device 2 into the fixed guide sleeve that has been fixed and welded. After the fixed bracket is aligned, pre-fix the fixed bracket with locking bolt 1.1, install the drive mechanism on the fixed bracket, and connect the output end of the drive mechanism to the power connecting rod 2.4.

[0059] 1-3. Use the positioning drill bit 2.9 to locate the hole, then use the diamond cutter 2.5 to cut a circular hole in the cold box plate (the diamond cutter should be positioned as follows during cutting). Figure 1 As shown in the figure, the locking can be released and adjusted during drilling and cutting; the cut circular cold box plate 4 is restricted to the front side of the cutter head by the anti-drop spring sheet, and the pearl sand in the cold box is blocked by the sand baffle plate 2.8 to prevent leakage.

[0060] Step 2: Insert the push-type guide sleeve (refer to...) Figure 2 ):

[0061] 2-1. Remove the drive mechanism of the rotary cutting and sand-blocking device 2;

[0062] 2-2. Insert the push-type guide sleeve 3 into the gap between the fixed positioning guide sleeve 1 and the rotary cutting and sand-blocking device 2. When the push-type guide sleeve contacts the locking bolt, loosen the locking bolt and continue inserting until the front end of the push-type guide sleeve 3 is in contact with the tower or condenser-evaporator shell 100. During the insertion process, the push-type guide sleeve 3 will push the diamond cutter 2.5 to rotate and make way (the posture of the diamond cutter after rotation is as follows). Figure 2 (as shown in the image);

[0063] 2-3. Secure the push-type guide sleeve 3 with locking bolt 1.1;

[0064] Step 3, Sand Removal (refer to...) Figure 3 ):

[0065] 3-1. Remove the entire rotary cutting and sand-blocking device 2;

[0066] 3-2. Clean the perlite from the inside of the fixed positioning guide sleeve 1 and the push-type guide sleeve 3;

[0067] Step 4: Inspect and seal the cold box panels (refer to...) Figure 4 ):

[0068] 4-1. Construction personnel and tools enter the propulsion guide sleeve, and the cutting equipment manhole 400 enters the container for maintenance;

[0069] 4-2. After the maintenance is completed, the cut-off circular cold box plate 4 will be partially repaired and welded to the boundary between the general part 3.1 and the special part 3.2 of the push-type guide sleeve, so that the general part and the special part are sealed and isolated.

[0070] 4-3. Loosen the locking bolt 1.1 and pull the push-type guide sleeve outward. When the circular cold box plate coincides with the cold box plate, first cut off the fixed positioning guide sleeve 1 from the cold box plate, then weld the special part of the push-type guide sleeve to the circular hole of the cold box plate, and finally cut off the general part of the push-type guide sleeve from the cold box plate. The cold box plate is then restored to its closed state, and the construction is completed.

[0071] Perlite is a lightweight porous material made from perlite after high-temperature expansion. This invention utilizes the low density of perlite to isolate a maintenance area by inserting a push-type guide sleeve into the perlite. In practice, applying a certain thrust will allow the push-type guide sleeve to be smoothly inserted into the perlite.

[0072] The sand-free inspection and maintenance process of this invention demonstrates significant advantages in the maintenance of fractionation towers in air separation units. Through precise positioning and local cleaning, it effectively protects the original structure of the cold box body and internal equipment and pipelines, improves operational efficiency and safety, saves maintenance time and costs, avoids excessive resource waste, and achieves efficient and safe local small-scale sand removal operations, providing stronger guarantees for the stable operation of air separation units.

[0073] It should be noted that the apparatus and process involved in this invention are performed under the premise that the maintenance points of the cold box have been determined. As for how to determine the maintenance points, precise detection is used to pinpoint the specific location of the perlite failure or equipment requiring maintenance, avoiding the complete removal of the entire insulation layer. During implementation, it is necessary to analyze the stress conditions of different parts and the temperature distribution in the low-temperature zone, based on the equipment layout diagram, steel structure diagram, piping diagram, and other data of the cold box, to determine the specific area where the perlite has failed or equipment requires maintenance. For the identified failure points, appropriate tools and procedures are used for local cleaning. The above-mentioned technology for determining maintenance points is a conventional technique in the industry and is unrelated to the content to be protected by this invention; therefore, it will not be elaborated upon here.

[0074] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A non-sand-removal maintenance device for a cold box in an air separation unit, wherein a tower or condenser-evaporator cylinder is provided in the central area of ​​the cold box, and the area between the tower or condenser-evaporator cylinder and the cold box plate is filled with perlite; characterized in that, The sand-free repair device includes: A fixed positioning guide sleeve is welded to the outside of the cold box plate, and the surface of the fixed positioning guide sleeve is provided with several locking bolts along the circumferential direction; A rotary cutting and sand-blocking device includes a fixed support, a cutter head, and a drive mechanism. The front end of the cutter head is equipped with at least a pair of diamond-shaped cutters. The drive mechanism drives the cutter head to rotate, thereby cutting circular holes in the cold box plate using the diamond-shaped cutters. A push-type guide sleeve, wherein the front end of the push-type guide sleeve matches the shape of the outer surface of the tower or condenser-evaporator shell, and the push-type guide sleeve can be inserted into a circular hole along the gap between the fixed positioning guide sleeve and the rotary cutting and sand-blocking device until the end of the push-type guide sleeve is in contact with the tower or condenser-evaporator shell. When the push-type guide sleeve contacts and pushes the diamond cutter during insertion, the diamond cutter can rotate inward. The diameter of the cut-off circular cold box plate is smaller than the inner diameter of the push-type guide sleeve.

2. The non-sand-removal maintenance device for the cold box of an air separation unit according to claim 1, characterized in that, A positioning drill bit is located at the center of the cutter head.

3. The non-sand-removal maintenance device for the cold box of an air separation unit according to claim 2, characterized in that, The positioning drill bit is equipped with an anti-detachment spring that can automatically spring outward.

4. A non-sand-removal maintenance device for the cold box of an air separation unit according to claim 1, characterized in that, The cutter head is fixedly provided with a cutter holder on each side. The diamond cutter is fixed to the cutter holder by bolts or reverse thread bolts, so that the diamond cutter can rotate inward under the push of the pusher sleeve from the outside to the inside.

5. A non-sand-removal maintenance device for the cold box of an air separation unit according to claim 1, characterized in that, The drive mechanism is detachably mounted on the rear side of the fixed bracket, and the cutter head is connected to the drive mechanism via a power linkage.

6. A non-sand-removal maintenance device for the cold box of an air separation unit according to claim 5, characterized in that, The drive mechanism includes a motor bracket and a motor and a reducer fixedly mounted on the motor bracket. The motor bracket is detachably connected to the rear side of the fixed bracket, and the output end of the reducer is connected to the power linkage.

7. A non-sand-removal maintenance device for the cold box of an air separation unit according to claim 1, characterized in that, A sand baffle is provided on the front side of the cutter head.

8. A non-sand-removal maintenance device for the cold box of an air separation unit according to claim 1, characterized in that, The propulsion guide sleeve includes a general part and a special part. The cut-off circular cold box plate is welded to the boundary between the general part and the special part. After the repair is completed, the cut circular hole is filled.

9. A non-sand-removal maintenance device for the cold box of an air separation unit according to claim 8, characterized in that, The front end of the push-type guide sleeve is provided with a washer.

10. A maintenance method for a non-sand-removal maintenance device for the cold box of an air separation unit as described in any one of claims 1-9, characterized in that, Includes the following steps: Step 1, Cutting the cold box panels: 1-1. First, weld the fixed positioning guide sleeve to the cold box plate where the hole needs to be made; 1-2. Install a rotary cutting and sand-blocking device inside the fixed guide sleeve that has been welded in place; 1-3. A circular hole is cut into the cold box plate using a diamond cutter. The size of the circular hole matches the outer diameter of the push-type guide sleeve. The diameter of the cut circular cold box plate is slightly smaller than the inner diameter of the push-type guide sleeve. Step 2: Insert the push-type guide sleeve: 2-1. Remove the drive mechanism of the rotary cutting and sand-blocking device; 2-2. Insert the push-type guide sleeve into the gap between the fixed positioning guide sleeve and the rotary cutting and sand-blocking device until the front end of the push-type guide sleeve is in contact with the tower or condenser-evaporator shell. During the insertion process, the push-type guide sleeve will push the diamond cutter to rotate and make way. 2-3. Secure the push-type guide sleeve with locking bolts; Step 3, Sand Removal: 3-1. Remove the rotary cutting and sand-blocking device; 3-2. Clean the perlite inside the fixed positioning guide sleeve and the push-type guide sleeve; Step 4: Inspect and seal the cold box panels: 4-1. Construction personnel and tools enter the propulsion guide sleeve, and the cutting equipment manhole is used for container maintenance. 4-2. After the maintenance is completed, the cut-off circular cold box plate will be partially repaired and then welded to the boundary between the general part and the special part of the push-type guide sleeve, so that the general part and the special part are sealed and isolated. 4-3. Loosen the locking bolts and pull the push-type guide sleeve outward. When the circular cold box panel overlaps with the cold box panel, first cut and remove the fixed positioning guide sleeve from the cold box panel. Then weld the special part of the push-type guide sleeve onto the circular hole of the cold box panel. Finally, cut and remove the general part of the push-type guide sleeve from the cold box panel. The cold box panel is then restored to its closed state, and the construction is complete.

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