Hoisting construction method for overhauling heat exchanger

Abstract

The invention relates to the field of equipment maintenance, in particular to a heat exchanger maintenance hoisting construction method which comprises the following steps: (1) determining a hoisting area of a device frame according to the position of a heat exchanger in the device frame; (2) carrying out structural transformation on a hoisting area of the device frame, and providing a hoisting point for hoisting equipment; (3) entering the device frame through the movement of the hoisting equipment, entering a hoisting area, and reaching a hoisting point position; (4) after reaching the hoisting point position, the hoisting equipment performs core pulling operation on the heat exchanger, hoisting is completed, and follow-up cleaning is performed; a 100-ton crane is adopted to enter the frame for direct core pulling operation; the maintenance time is 3 days, only the tube bundle drawing operation is needed, the operation time is greatly shortened, and rapid production recovery of the device can be achieved; the construction cost is low: a 100-ton crane is adopted for operation, and the construction cost is 30% of that of an original scheme; overall hoisting of the heat exchanger is not needed, only the tube bundle is drawn and installed, the tube bundle does not need to be moved out of the frame, and safety risks are low.

Description

Technical Field

[0001] The invention relates to the field of equipment maintenance, and in particular to a heat exchanger maintenance and hoisting construction method, which is mainly used for the disassembly and assembly of cleaning working tube cores of heat exchangers in chemical plants. Background Art

[0002] The heat exchanger of an aromatics unit needs to be overhauled and cleaned once every two years on average. Since the unit needs to be shut down during the overhaul, it has a great impact on the safety and benefits of the enterprise. It is very important to complete the overhaul quickly and with high quality. Due to the special working conditions on site, the heat exchanger is located inside the unit frame. In the past, a 300-ton crane was used to lift the heat exchanger out of the frame as a whole, and then move it to other locations for core extraction and cleaning. The operation took a long time (10 days) and had high safety risks.

[0003] The above existing method uses a 300-ton crane to lift the heat exchanger out of the frame as a whole, and then move it to another location for core cleaning. The entire operation process takes 10 days, which is long and has high maintenance costs. The specific implementation steps are: ⑴Remove all insulation of E101AB; ⑵Remove the pipelines of the tube side and shell side system of E101AB, and use a crane to move the pipelines out of the frame; ⑶Remove the flange and support connection between E101AB, and remove the foundation bolts of the heat exchanger; ⑷Use a 300-ton crane to lift E101A and E101B out of the frame respectively, and install them on a temporary base; ⑸Use a crane with a core pulling machine to pull out the E101A and E101B tube bundles, and clean them; ⑹Reinstall the tube bundles; ⑺Perform water pressure test on the tube side and shell side of the heat exchanger; ⑻Use a 300-ton crane to lift E101A and E101B back into the frame and install them as a whole; ⑼Lift the heat exchanger pipe into the frame for installation.

[0004] The existing technology has the following disadvantages: (1) Long operation time: The operation time is 10 days, and the device is in a shutdown state during the construction period, which has a great impact on the production safety and benefits of the enterprise; (2) High construction cost: The existing construction technology requires the use of a 300-ton crane to assist the operation for 10 days, and the crane rental fee is at least RMB 100,000; (3) High safety risk: The heat exchanger (the heat exchanger is a double-unit combined type, weighing 50.8 tons) is removed from the frame as a whole and then hoisted back to its original position after inspection, which poses a high safety risk to the operation. Summary of the invention

[0005] In view of the problems with the existing technology, the inspection and maintenance center conducted on-site surveys and, under the premise of ensuring safety, partially modified the on-site frame platform and tie rods, and developed a heat exchanger maintenance hoisting construction method. This method is that a crane enters the interior of the frame to perform heat exchanger core extraction and cleaning work. There is no need for a large-tonnage crane to lift the heat exchanger out of the frame. The maintenance work can be completed in 3 days, and the maintenance work can be completed safely and quickly.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a heat exchanger maintenance and hoisting construction method, comprising the following steps: (1) Determine the hoisting area of ​​the device frame by the location of the heat exchanger inside the device frame; (2) Structural modification of the hoisting area of ​​the device frame to provide hoisting points for the lifting equipment; (3) Enter the device frame and the lifting area through the movement of the lifting equipment to reach the lifting point; (4) After reaching the lifting point, the lifting equipment performs the core extraction operation on the heat exchanger, and completes the lifting for subsequent cleaning; Further, the lifting equipment is a crane, which includes a body part and a main arm rotatably mounted on the body, one end of the main arm is rotatably mounted on the body part, and a hook is arranged at the front end of the main arm; Furthermore, the device frame described in step (1) includes a frame body with a two-layer platform, the heat exchanger is located in the lower area of ​​one side of the frame body, the first layer area directly below the secondary platform is an open space, and the heat exchanger is installed inside the frame adjacent to the open space; when the heat exchanger needs to be cored out, it needs to be pulled out from the frame where the heat exchanger is located toward the open space; Furthermore, a hoisting area is set at the second-floor platform position corresponding to the open space; the structural transformation of the hoisting area is to open a rectangular hollow area on the second-floor platform for the crane main arm to extend into, forming a hoisting point in this area; Furthermore, the rectangular hollowed-out area forms two separate spaces separated front and back, each separate space is formed by removing 6-meter-wide purlins and iron plates on the second-floor platform; the two separate spaces front and back are separated by the frame body crossbeam; Furthermore, the front and back combination of the two separate spaces forms an entire hoisting area; Furthermore, in step (3), the crane enters the hoisting area and reaches the hoisting point by operating the walking path of the crane and taking into account the spatial limitation relationship between the crane and the hoisting area; The rectangular hollowed-out area opened on the second-floor platform is 6 meters wide and 9 meters high from the surface of the open space below; The operation method of allowing the crane to enter the lifting area and reach the lifting point by operating the walking path of the crane includes the following steps: Before the following operation steps, the selection of crane and the selection of counterweight are included; in this plan, after checking the crane load curve table, a 100-ton cable-type telescopic main boom crane is used, with a 20-ton counterweight. Under the conditions of an 11-meter working diameter and a 16.8-meter boom length, the rated load of the crane is Q rated = 24.3t, which can meet the work needs of lifting 21 tons (14 tons of pipe bundles and 7 tons of pumping machines). At the same time, the crane tires can withstand the safe movement of the counterweight; (1) Determine the crane pre-positioning position based on pre-design calculations; The tail of the crane is hoisted toward the frame hoisting area (north), and the crane legs are half extended to hoist and lay the steel pad in place; (2) The crane is far away from the lifting area and the crane boom rotates without hindrance; After the mast is closed, the crane moves 3 meters southward, and the main boom is swung to the rear of the vehicle (rotated) behind the outriggers, and the main boom is slightly raised to point to the hoisting area (corresponding to the position of E-101C / D); (3) The crane returns and the crane's main arm enters the frame and reaches the lifting point; Slightly lift the outriggers, move the crane back to its original position to the north, and fully extend the legs to support it on the laid steel pads; adjust the angle and length of the main arm, and extend the rod from the lifting area (corresponding to the position of E-101C / D) to the E-101A / B position frame (a hollow area has been opened here in advance).

[0007] The determination of the above-mentioned crane pre-positioning position needs to take into account the crane's operating radius of 11 meters to meet the lifting requirements; since the rectangular hollowed-out area opened on the second-floor platform is 6 meters wide and 9 meters high from the surface of the open space below; therefore, the crane's operating diameter cannot be greater than 11 meters (exceeding 11 meters does not meet the lifting capacity requirements); the crane's shortest arm length (basic arm) is 12 meters; these three conditions determine that the crane cannot lift the boom or turn the boom at the lifting position because the crane's basic arm is blocked by the frame at this time; so step (2) is adopted.

[0008] In the step (2), the crane is driven 3 meters away from the frame (towards the south) until the distance from the center point of the crane turntable to the edge of the front beam of the frame hoisting area is at least greater than 12 meters, that is, the distance the crane is driven out is greater than the length of the crane's main arm, so that the main arm can be rotated (so that the front hook of the main arm faces the frame hoisting area) without scratching the frame; the main arm is rotated at a position 3 meters away from the frame hoisting area.

[0009] In the selection of the above cranes, the use of a cable-type telescopic main boom crane is based on the consideration of different crane performances. The advantages and disadvantages of the specific crane types are: Crane boom: The crane boom is an important part of the crane. Its function is to use the pulley block at the top of the boom to support the hoisting wire rope to lift heavy objects. The main boom adopts a box-type retractable structure, and the auxiliary arm is a truss structure for lifting lighter objects. Basic boom length of crane: the length of the main boom of the crane before it is extended; Hydraulic cylinder pin-type telescopic main boom: The telescopic main boom is driven by a hydraulic cylinder. The advantage is that the driving force is strong and it is used for large load lifting. The disadvantage is that the main boom is heavy and the main boom is segmented telescopic due to the hydraulic cylinder pin structure. Rope-type telescopic main boom: There are steel wire ropes and pulley structures inside the main boom. Advantages: Light weight, the main boom can be flexibly extended and adjusted in length; Disadvantages: The driving capacity of the rope-type structure is lower than that of the hydraulic cylinder type, and the lifting capacity is limited.

[0010] Therefore, among the above crane types, the crane suitable for this application is a rope-type telescopic main boom crane; the analysis idea is that a conventional 100-ton crane has a hydraulic cylinder pin-type telescopic main boom, and its arm can only be extended and retracted in sections, and the arm length cannot be fine-tuned steplessly. Therefore, fine operations cannot be completed in confined spaces. For such special operations, only a crane with a rope-type telescopic main boom can be selected; a rope-type telescopic main boom crane has a low lifting capacity, so the load calculation of the crane is a key link; at the same time, during the movement and arm-lifting process of the crane, the tires are in a load counterweight state, which requires that the crane's lifting capacity meet the construction, and the counterweight should be reduced as much as possible to reduce the pressure of the counterweight on the tires during the crane's displacement.

[0011] Compared with the traditional method, the beneficial effects of the hoisting construction method of this scheme are: Use a 100-ton crane to enter the frame and directly perform core extraction operations; (1) Short operation time: The maintenance time is 3 days, and only the pipe bundle extraction and installation operation is required, which greatly shortens the operation time and enables the device to quickly resume production, which is beneficial to the company's benefits; (2) Low construction cost: Using a 100-ton crane, the construction cost is 30% of the original plan, and the crane rental fee is about 20,000 yuan; (3) Low safety risk: Since there is no need to hoist the heat exchanger as a whole, only the tube bundle needs to be pulled out. The total weight of the core pulling machine and the heat exchanger tube bundle is 21 tons, and there is no need to remove it from the frame, so the safety risk is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic plan view of the maintenance construction of the hoisting construction method of the present invention.

[0013] Figure 2 for Figure 1 Schematic diagram of the working status of maintenance construction.

[0014] Figure 3This is a schematic diagram of the position relationship between a heat exchanger, a device frame and a crane at a construction site according to an embodiment of the present invention.

[0015] Figure 4 This is a schematic diagram of the hoisting area of ​​the second-floor platform modification of the device frame of this scheme and the crane hook located in the hoisting area.

[0016] Figure 5 for Figure 3 Schematic diagram of the location of the heat exchanger.

[0017] Figure 6 Schematic diagram of the structure for preparing the crane to perform the crane main arm flipping operation away from the device frame lifting area.

[0018] Figure 7 This is a schematic diagram of the interference between the crane's main arm and the device frame when the crane is not far away from the lifting area of ​​the device frame.

[0019] Figure 8 This is a structural diagram of the crane returning to the device frame hoisting area, entering the hoisting area and arriving at the hoisting point (preparing for core extraction of the heat exchanger).

[0020] In the figure, 1, heat exchanger E101A / B, 2, device frame, 3, lifting area, 4, crane main arm, 5, second-floor platform, 6, frame body beam, 7, inclined tie rod, 8, small beam, 9, lifting area width, 3.1, front end beam of the installation area, 3.2, rear end beam of the installation area. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0022] like Figure 1-8 As shown, E101A / B among multiple sets of heat exchangers at a certain site is used as a specific embodiment; its maintenance and hoisting construction method is: (1) Determine the hoisting area 3 of the device frame 2 by the location of the heat exchanger E101A / B inside the device frame 2; (2) Structural modification of the hoisting area 3 of the device frame 2 to provide a hoisting point for the hoisting equipment; (3) Enter the device frame 2 and the lifting area 3 through the movement of the lifting equipment to reach the lifting point; (4) After reaching the lifting point, the lifting equipment performs the core extraction operation on the heat exchanger, and completes the lifting for subsequent cleaning; Further, the lifting equipment is a crane, which includes a body part and a main arm 4 rotatably arranged on the body, one end of the main arm 4 is rotatably mounted on the body part, and a hook is arranged at the front end of the main arm 4; Furthermore, the device frame 2 described in step (1) includes a frame body with a two-layer platform 5, the heat exchanger is located in the lower area of ​​one side of the frame body, the first layer area directly below the secondary platform 5 is an open space, and the heat exchanger is installed inside the frame adjacent to the open space; when the heat exchanger needs to be cored out, it needs to be pulled out from the frame where the heat exchanger is located toward the open space; Furthermore, a hoisting area 3 is set at the position of the second-floor platform 5 corresponding to the open space; the structure of the hoisting area 3 is modified to open a rectangular hollow area on the second-floor platform 5 for the crane main arm 4 to extend into, forming a hoisting point in this area; Furthermore, the rectangular hollowed-out area forms two separate spaces separated front and back, each separate space is formed by removing six-meter-wide purlins and iron plates on the second-floor platform 5; the two separate spaces front and back are separated by the frame body crossbeam 6; Furthermore, the front and rear combination of the two separate spaces forms an entire hoisting area 3; It should be noted that before the crane enters the lifting area 3, it is necessary to dismantle part of the frame structure of the heat exchanger to facilitate unobstructed construction. The specific operation process is to dismantle the diagonal braces 7 and small beams 8 of the west side frame of E101A / B. Figure 5 As shown; At the same time, the corresponding heat exchanger peripheral structure needs to be dismantled before the crane enters the work site; specifically, cut the E101A tube pass outlet pipeline bracket, E101A shell pass inlet pipeline bracket, and E101C tube pass outlet pipeline bracket by 30mm, and pad a 30mm pad at the bottom; remove the lower backwash and east side flange bolts of the S pipeline between the E101A / B and E101C / D tube passes, remove the upper and lower instruments and wiring of the S pipeline; remove the S pipeline and pipe box head between the E101A / B and E101C / D tube passes; After completing the above pre-treatment work before the lifting construction, command the 100-ton crane to enter the operation site according to the construction plan; Therefore, the operation steps of operating the crane's travel path to allow the crane to enter the hoisting area 3 and reach the hoisting point are as follows: Determine the crane pre-occupancy position based on pre-design calculations; ① The crane enters the site shown in the figure, and the radius between the crane and the operation point is measured to be 11 meters. The rear of the crane faces north. At this time, the main arm of the crane points to the south and is outside the device frame 2; command the crane to half-extend its legs to lay the steel pad in place; (The purpose of this step is to put the steel pad in place first, because when the crane swing arm returns to this position again in the next step, the crane arm has already extended into the frame and cannot lift the steel pad by itself); The crane main arm 4 rotates without hindrance; ② After the steel pad is in place, the crane retracts the boom and directs the crane to move 3 meters southward. After the crane extends its outriggers, it swings the boom toward the rear of the vehicle and slightly raises the boom toward the frame hoisting area 3; (The purpose of the crane moving 3 meters southward is that the basic boom length of the crane is 12 meters. If the boom is swung at the original position, it will scrape the frame columns and beams. After calculation, it needs to move 3 meters southward so that the main boom has space to swing to the rear of the vehicle); The crane returns, and the crane main arm 4 enters the frame and reaches the lifting point; ③ Slightly lift the outriggers and move the crane slowly toward the north, lifting the boom while moving and coordinating the operations. When the vehicle moves to a position with a radius of 11 meters from the work point, stop moving; extend the crane's full legs to support it on the laid steel pads; hang a 20-ton counterweight on the crane; adjust the boom angle and length, and extend the boom from three locations in the hoisting area of ​​the west frame of E-101C / D to above the west frame of E-101A / B.

[0023] It should be noted that the crane movement and arm lifting process must adopt the method of lifting the arm and moving at the same time, so that the arm can be extended from the E-101C / D west side frame hoisting area 3 to the top of the E-101A / B west side frame; During the gradual movement of the crane, if the main arm is raised too early, the main arm will scrape the front beam 3.1 of the lifting area 3; if the main arm 4 is raised too late, the main arm 4 will scrape the rear beam 3.2 of the lifting area 3; when the crane hook reaches the lifting point of the lifting area, the hook is lowered from a separate space at the rear end of the lifting area 3.

[0024] ④ The crane cooperates with the core-pulling machine to pull out the heat exchanger tube bundle; after the tube bundle is cleaned, it is reinstalled using the core-pulling machine; the E-101A / B tube box head is reinstalled, the heat exchanger is subjected to water pressure test, and the heat exchanger pipe is reinstalled; the same as step ④, but the process is reversed.

[0025] The essence of this solution is that the crane enters the frame to perform core extraction and cleaning of the heat exchanger. There is no need for a large-tonnage crane to lift the heat exchanger out of the frame. The maintenance work can be completed in 3 days. The maintenance work can be completed safely and quickly. This method has been successfully implemented in maintenance work.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0028] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0030] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0031] The above examples are only the best embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A heat exchanger maintenance and hoisting construction method, characterized in that: The following steps are involved: (1) Determine the hoisting area of ​​the device frame by the location of the heat exchanger inside the device frame; (2) Structural modification of the hoisting area of ​​the device frame to provide hoisting points for the lifting equipment; (3) Enter the device frame and the lifting area through the movement of the lifting equipment to reach the lifting point; (4) After reaching the lifting point, the lifting equipment performs the core extraction operation on the heat exchanger, and completes the lifting for subsequent cleaning.

2. A heat exchanger maintenance and hoisting construction method according to claim 1, characterized in that: The lifting device is a crane, which comprises a vehicle body and a main arm rotatably arranged on the vehicle body, one end of the main arm is rotatably installed on the vehicle body, and a hook is arranged at the front end of the main arm.

3. A heat exchanger maintenance and hoisting construction method according to claim 1, characterized in that: The device frame described in step (1) includes a frame body with a two-layer platform, the heat exchanger is located in the lower area of ​​one side of the frame body, the first layer area directly below the secondary platform is an open space, and the heat exchanger is installed inside the frame adjacent to one side of the open space.

4. A heat exchanger maintenance and hoisting construction method according to claim 3, characterized in that: A hoisting area is set at the second-floor platform position corresponding to the open space; the structural transformation of the hoisting area is to open a rectangular hollow area on the second-floor platform for the crane main arm to extend into, forming a hoisting point in this area.

5. A heat exchanger maintenance and hoisting construction method according to claim 4, characterized in that: The rectangular hollowed-out area forms two separate spaces separated by front and rear, each of which is formed by removing 6-meter-wide purlins and iron plates on the second-floor platform; the two separate spaces are separated by the frame beams; the front and rear combination of the two separate spaces constitutes an entire lifting area.

6. A heat exchanger maintenance and hoisting construction method according to claim 1, characterized in that: In the step (3), the crane enters the hoisting area and reaches the hoisting point by operating the walking path of the crane and taking into account the spatial limitation relationship between the crane and the hoisting area.

7. A heat exchanger maintenance and hoisting construction method according to claim 6, characterized in that: The steps to make the crane enter the hoisting area and reach the hoisting point by operating the crane's travel path: (1) Determine the crane pre-positioning position based on pre-design calculations; The tail of the crane is hoisted toward the frame hoisting area, and the crane legs are half extended to hoist and lay the steel pad in place; (2) The crane is far away from the lifting area and the crane boom rotates without hindrance; After the mast is retracted, the crane moves 3 meters southward, swings the main boom to the rear of the vehicle behind the outriggers, and slightly raises the main boom to point to the hoisting area corresponding to the position of E-101C / D; (3) The crane returns and the crane's main arm enters the frame and reaches the lifting point; Slightly lift the outriggers, move the crane back to its original position to the north, and fully extend the legs to support it on the laid steel pads; adjust the angle and length of the main arm, and extend the rod from the hoisting area corresponding to the position of E-101C / D to above the frame of the position of E-101A / B.

8. A heat exchanger maintenance and hoisting construction method according to claim 7, characterized in that: The crane type and counterweight selection are calculated before the crane enters the lifting area and reaches the lifting point. After checking the crane load curve, a 100-ton rope-type telescopic main boom crane with a 20-ton counterweight is used. With an operating diameter of 11 meters and a boom length of 16.8 meters, the rated load of the crane is Qrated = 24.3t.

9. A heat exchanger maintenance and hoisting construction method according to claim 7, characterized in that: In step (2), the crane is driven 3 meters away from the frame, and the distance from the center point of the crane turntable to the edge of the front beam of the frame hoisting area is at least greater than 12 meters, that is, the distance the crane is driven is greater than the length of the crane's main arm; The main arm is rotated at a position 3 meters away from the frame lifting area when the crane is moved away.

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