A construction method for handling jammed bearings in an ethylene plant ERC unit.

Abstract

This invention discloses a construction method for handling bearing jamming in an ERC (Enhanced Refrigerant Compressor) unit of an ethylene plant. The method involves numbering the sealing bolts of the compressor cylinder, heating the sealing bolts sequentially on both sides of the compressor until a preset temperature is reached, then loosening and removing the sealing bolts. First, the cylinder head is lifted using a jack screw test. After checking the gap between the upper and lower cylinder sealing surfaces to confirm cylinder head balance, the cylinder head is lifted using hoisting equipment and placed stably on a fixture capable of supporting its total weight. The upper and lower bearing assemblies are then installed onto the rotor shaft. A crane is used to apply an upward force to the jammed bearing area, while a traveling crane horizontally lifts the rotor. Once the bearing assembly is completely separated from the lower casing, the rotor is lifted out of the cylinder and placed stably on a rotor support. The bearings are removed from the rotor support, and damaged areas are repaired. Finally, the rotor and cylinder head are reinstalled. This method is safe, efficient, has a low risk of damage, and is highly versatile. After treatment, all performance indicators of the unit meet the standards, providing a reliable technical basis and practical reference for handling bearing jamming incidents in similar large centrifugal compressor units.

Description

Technical Field

[0001] This invention belongs to the field of centrifugal compressor unit installation and maintenance technology, specifically relating to a construction method for handling bearing jamming in an ethylene plant ERC unit (ethylene compressor unit). Background Technology

[0002] The three main units of an ethylene plant—the cracked gas compressor (CGC), the ethylene compressor (ERC), and the propylene compressor (PRC)—are core and critical equipment in the ethylene production process. Among them, the ERC (ethylene compressor unit), as the core unit of the ethylene compression section, often employs imported large-scale horizontally split multi-stage centrifugal compressors, which are complex in structure, require high machining precision, and operate under harsh conditions. Bearings, as the core supporting components of the unit's rotating parts, directly bear the radial and axial loads of the rotor; their operating status directly determines the stability, reliability, and service life of the unit.

[0003] During unit installation and maintenance, or after the unit has been idle for a long time, bearing bushes are prone to jamming. If not handled properly, this can easily cause irreversible damage such as scratches on the bearing bush alloy layer, wear on the rotor surface, and collisions between the impeller and the diaphragm. This will not only significantly increase equipment maintenance costs and extend maintenance cycles, but may also lead to the shutdown of the ethylene plant, resulting in huge economic losses.

[0004] Currently, the industry's methods for handling jammed bearings in large centrifugal compressor units are relatively limited. These methods often employ crude approaches such as applying stress to forcibly drag the bearings or violently dismantling the unit, or relying on specialized tools provided by the equipment manufacturer for simultaneous lifting of the bearings and rotor. The former easily causes secondary damage to core components such as the rotor, bearings, and partitions, while the latter has drawbacks including complex procedures, the need for additional specialized tools, and the risk of rotor tilting and collisions during lifting. Neither method meets the core requirements of "safety, efficiency, and low damage" in handling jammed bearings.

[0005] Therefore, there is an urgent need for an optimized and improved method for handling bearing jamming, to address the shortcomings of existing technologies, maximize the protection of core components of the unit, shorten the handling cycle, reduce maintenance costs, and provide reliable technical support and practical reference for handling similar problems in similar units. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a construction method for handling bearing jamming in ERC units of ethylene plants. Through scientific analysis of the causes of jamming, demonstration of optimized dismantling schemes, design of standardized operation procedures, and strict testing and repair procedures, the method achieves safe, efficient, and low-damage handling of bearing jamming, effectively protecting core components such as rotors, bearings, and diaphragms, and ensuring that the performance indicators of the unit after treatment meet the design requirements and equipment manual standards.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a construction method for handling bearing jamming in an ethylene plant ERC unit, wherein the jammed part is the contact area between the casing and the bearing assembly, including: Step 1: Number the sealing bolts of the compressor cylinder, heat the sealing bolts on both sides of the compressor in sequence, and after reaching the preset temperature, loosen and remove the sealing bolts; Step 2: First, use the set screw to test lift the cylinder head, check the gap between the upper and lower cylinder sealing surfaces to confirm the cylinder head is balanced, then use lifting equipment to lift the cylinder head and place it stably on a tooling that can bear the total weight of the cylinder head. Step 3: Install the upper and lower bearing assemblies onto the rotor shaft. Use a crane to apply an upward force to the jammed part of the bearing, and at the same time use a crane to lift the rotor horizontally. After the bearing assembly is completely separated from the lower housing, lift the rotor out of the cylinder and place it stably on the rotor support. Step 4: Remove the bearing shell from the rotor support and repair the damaged parts; Step 5: Reassemble the rotor and cylinder head.

[0008] In a preferred embodiment, the heating temperature in step one is 75–90°C.

[0009] In a preferred embodiment, in step one, a striking wrench and a hydraulic torque wrench are used to loosen the sealing bolts, and the hydraulic pressure of the hydraulic torque wrench is controlled to not exceed 70 MPa.

[0010] In a preferred embodiment, in step two, before lifting the cylinder head, a guide rod is installed on the frame at the left front end and right rear end of the cylinder head to limit the lifting path of the cylinder head. The guide rods are smooth and coated with lubricant.

[0011] As a preferred embodiment, in step two, when lifting the cylinder head, the front outrigger lugs are lifted using two 10-ton slings in conjunction with a 25-ton lifting device, while the rear outrigger lugs are balanced using two 10-ton hand-operated chain hoists.

[0012] In a preferred embodiment, during step three, lubricating oil is continuously added to the jammed part of the bearing during the rotor lifting process to reduce frictional damage during separation.

[0013] In a preferred embodiment, in step three, the crane's load indicator is observed during lifting. When the displayed weight is consistent with the weight of the rotor plus the weight of the single-sided bearing, an upward force is applied to the bearing shell adhesion point to maintain the lifting weight stability. After the adhesion point separates, the rotor is lifted to the rotor support.

[0014] As a preferred embodiment, in step four, when repairing the damaged part, the damaged part of the bearing seat is ground and repaired with a mixed file and sandpaper. The lower bearing is placed in the bearing seat coated with red lead powder and ground to repair the high point so that the contact area reaches more than 85%.

[0015] In a preferred embodiment, in step five, the tiles, tile bases, inside the casing, rotor impeller, and comb seals are cleaned before reassembly.

[0016] As a preferred embodiment, in step five, after reassembly, sealant is applied to the sealing surfaces of the upper and lower cylinder bodies. The sealant is prepared according to the mass ratio of curing agent CAT-RA to sealant KE-201Kg of 8:1000, stirred evenly, and then applied. The cylinder head reassembly and bolt tightening are completed within 5 to 6 hours.

[0017] Compared with existing technologies, this invention optimizes the dismantling process by employing a small crane to assist in separating the bearing shell from the casing. This effectively avoids problems such as rotor tilting and impeller collision caused by forced dragging and simultaneous lifting, maximizing the protection of core components such as the rotor, bearing shell, and diaphragm, reducing the probability of irreversible damage, and significantly reducing equipment maintenance costs. Furthermore, the method provided by this invention reduces operational difficulty, shortens the bearing shell jamming handling cycle, and enables rapid restoration of unit operation, minimizing economic losses caused by ethylene plant shutdowns. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the optimized demolition scheme of the present invention; The markings in the diagram are: 1-support frame, 2-rotor, 3-sling, 4-rubber plate. Detailed Implementation

[0019] Existing technologies for handling stuck bearings in ERC units of ethylene plants often result in damage to core components, complex operating procedures, high safety risks, and low processing efficiency. Based on this, a typical embodiment of the present invention provides a construction method for handling stuck bearings in ERC units of ethylene plants, the specific steps of which are as follows.

[0020] Step S1: Emergency Shutdown Procedures When a bearing jams during reinstallation or maintenance, immediately cease all exploratory operations, including chain hoisting, jacking, and other external forces. Do not apply excessive force to force the bearing, as this can lead to irreversible damage such as rotor scratches, bearing alloy layer peeling, or impeller-diaphragm collisions due to uneven stress. Simultaneously, meticulously record the operational status at the moment of jamming (e.g., bearing rotation angle, lubrication application), stress parameters (e.g., chain hoist pull, jack push), and environmental parameters (temperature, humidity). This will provide accurate and complete data for subsequent analysis of the jamming cause and assessment of the damage extent.

[0021] Step S2: Analysis of the cause of jamming and the extent of damage Based on the unit installation process, settling time, and on-site inspection results, the core causes of bearing jamming were comprehensively analyzed and mainly divided into two categories: First, the unit was left to stand for a long time (usually more than 7 days), which caused slight deformation of the material at the contact point between the casing and the bearing assembly, resulting in adhesion; Second, the local installation clearance did not meet the design requirements during bearing reinstallation, and insufficient lubrication caused initial jamming. Subsequent external dragging operations further aggravated the jamming, eventually causing the bearing to completely jam.

[0022] Based on the above causes of jamming and combined with on-site visual inspection, the extent of damage to the bearing and related components is estimated to be one of three possibilities: ① Only the contact area between the bearing assembly and the lower housing is stuck, and there is no damage to the sliding part between the bearing and rotor 2; ② The alloy steel layer of the sliding part between the bearing and rotor 2 has slight scratches, but the bearing body itself is not damaged; ③ The alloy steel coating of the bearing is severely damaged, with defects such as peeling and cracks, or there are obvious scratches on the surface of rotor 2.

[0023] Step S3: Determine the demolition plan Based on the above damage analysis, the core handling principle is clarified: regardless of the degree of damage to the bearing and related components, the low-pressure cylinder cover must be removed, and the rotor 2 and bearing assembly must be lifted out as a whole for comprehensive inspection and targeted treatment, so as to minimize the risk of damage to the core components of the unit during subsequent operations.

[0024] For the demolition phase, by comparing the feasibility, safety, and economy of the two schemes, the optimized demolition scheme was finally determined: Option 1 (existing technology provided by the equipment manufacturer): A special fixing tool is machined to firmly connect the bearing assembly to rotor 2, enabling synchronous lifting of the bearing and rotor 2. This option has two major drawbacks: First, if the bearing is adhered to the lower casing, torque will be generated at the adhesion point during lifting, and the moment the adhesion separates, rotor 2 may tilt, leading to impeller collision with the baffle plate. Second, additional special tools are required, increasing processing costs and extending maintenance cycles, thus failing to meet the requirements for efficient processing.

[0025] Option 2 (the optimized solution provided by this invention): Accurately install the upper and lower bearing bush assemblies to their corresponding positions on the rotor shaft. Utilize existing materials (channel steel, steel plates, etc.) to construct a small crane, applying a uniform upward force to the jammed area of ​​the bearing bush. The small crane includes a support frame 1 fixed to the machine frame, with lifting rings connected to the support frame 1, which cooperate with a hand-operated hoist. Simultaneously, use an overhead crane to horizontally lift the rotor 2. After the bearing bush assembly is completely separated from the lower casing, smoothly lift the rotor 2 out of the cylinder. This solution requires no additional specialized tools, is simple to operate, and has low cost. It effectively prevents the rotor 2 from tilting, minimizing the risk of damage to core components.

[0026] Step S4: Cylinder block bolt removal The core purpose of this step is to prevent deformation or damage during bolt removal, ensuring that the cylinder head can be removed smoothly and safely. The specific operating procedure is as follows: 1. Tool preparation: Prepare tools such as hammer wrenches, bolt heaters, and hydraulic torque wrenches in advance. Thoroughly check the performance of the tools to ensure that they are in good condition and meet the operating requirements, so as to avoid affecting the disassembly quality due to tool failure.

[0027] 2. Record preparation: Create a special record form for bolt heating temperature and heating time, and assign a unique number to each cylinder sealing bolt to ensure accurate bolt matching during disassembly and reassembly, which will facilitate subsequent traceability.

[0028] 3. Parameter settings: Strictly adjust the hydraulic pressure of the hydraulic torque wrench to no more than 70MPa to avoid excessive pressure causing bolt deformation or damage.

[0029] 4. Heating and loosening: Using the axial centerline of the compressor as the center line, heat the cylinder sealing bolts simultaneously from front to back on both sides. The heating temperature is strictly controlled between 75 and 90°C. After reaching the preset temperature, first use a tapping wrench to help loosen the bolts, and then use a hydraulic torque wrench to loosen the bolts at a uniform speed and smoothly to avoid uneven force on the bolts.

[0030] 5. Marking and storage: Before loosening the bolts, make clear and unique corresponding marks on the housing and nuts to ensure that they can be restored to their original tightened positions when reinstalled; after loosening the bolts, loosen them by 3-5 turns to prevent them from tightening again after cooling and shrinking; after disassembling the nuts, arrange them neatly in the order they were loosened in a dedicated storage area, and protect them from dust and collisions to facilitate subsequent reinstallation and storage.

[0031] Step S5: Cylinder head lifting guide During cylinder head lifting, to prevent the alloy steel plating of the upper cylinder head diaphragm from colliding with or scratching the rotor 2, a cylinder head lifting guide rod needs to be installed. The specific operation is as follows: 1. Guide rod assembly: Assemble the guide rod on the work platform, carefully check the smoothness of the guide rod surface, remove burrs, scratches and other defects, and then apply lubricant evenly to the surface of the guide rod to reduce frictional resistance during cylinder head lifting.

[0032] 2. Guide rod installation: Install one guide rod on the frame at the left front end and right rear end of the cylinder head. Ensure that the guide rods are firmly installed and accurately positioned to effectively guide the cylinder head to rise smoothly and prevent the cylinder head from tilting.

[0033] Step S6: Cylinder head lifting Cylinder head lifting is one of the core steps in handling seized bearings. Strict control of the lifting balance is necessary to prevent cylinder head tilting or collision. The specific operating procedure is as follows: 1. Preparations before lifting: ① Thoroughly remove all cylinder sealing nuts and use compressed air to thoroughly clean the bolt holes and cylinder surface of debris and dust to avoid impurities affecting the subsequent reinstallation sealing effect; ② Clean the surface of the set screws and apply lubricant evenly to ensure the set screws operate smoothly; ③ Prepare the tooling and lay rubber sheets on the upper part of the tooling where it contacts the cylinder head and rotor 2 to avoid damaging the cylinder head sealing surface, rotor shaft and other precision-machined parts; ④ Prepare dustproof plastic sheeting to seal the cylinder head and lower cylinder to prevent impurities from entering the equipment; ⑤ Operators should wear one-piece work clothes and properly store personal items such as mobile phones, tools, and measuring instruments or tie them to their wrists or clothes with ropes to prevent them from falling into the cylinder and damaging the equipment.

[0034] 2. Lifting Preparation: ① Confirm the cylinder head weight as 25t, perform load calculations on the lifting slings used for lifting to ensure their load-bearing capacity meets the lifting requirements and eliminate potential safety hazards during lifting; ② Use two 10-ton slings for the front outrigger lugs and two 10-ton hand-operated chain hoists for the rear outrigger lugs to adjust the overall balance during cylinder head lifting; ③ Use jacking screws to test lifting the cylinder head, check whether the cylinder head can be smoothly detached from the lower cylinder block, investigate potential jamming problems, and ensure smooth lifting.

[0035] 3. Smooth Lifting: Use the jack screws to slightly lift the cylinder head. Use a steel ruler to check the gaps at the four points on the front, back, left, and right sides of the upper and lower cylinder sealing surfaces to confirm that the upper cylinder head is in a balanced state. Adjust the hand-operated chain hoist to smoothly lift the cylinder head to a height of 20mm. Check the gaps again to ensure balance, and then slowly continue lifting. During the lifting process, measure the gap between the upper and lower cylinder sealing surfaces in real time and continuously adjust the balance to prevent the cylinder head from tilting. After the cylinder head is lifted to a height exceeding the guide rod, slowly hoist it onto a fixture that can bear the total weight of the housing. The surface of the fixture must be smooth and free of impurities to prevent scratching the cylinder head sealing surfaces.

[0036] Step S7: Remove the rotor The removal of rotor 2 must strictly follow the requirements of the equipment's accompanying documentation and maintenance manual. Special attention should be paid to protecting vulnerable components such as rotor 2, bearings, and dry gas seals. The specific operating procedure is as follows: 1. Gap Measurement: Before removing the rotor, measure the gaps between the sealing ring and the bushing of the return diaphragm plate, the gap between the wheel cover and the sealing ring, the shaft seal gap, and the radial and axial bearing gaps one by one, and record all measurement data in detail. If there are other parameters that need to be recorded in the equipment's accompanying documents, they must also be measured and recorded one by one to provide an accurate basis for subsequent reassembly and acceptance.

[0037] 2. Lifting point determination: Strictly follow the lifting position and procedure in the equipment's accompanying data, accurately locate the center of gravity of rotor 2, determine reasonable lifting point positions, and ensure that rotor 2 is subjected to uniform force during the lifting process to avoid tilting or deformation.

[0038] 3. Protective Lifting: ① Remove the C-type retaining ring from the internal sealing oil supply pipe, screw the disassembly tool into the cylinder bolt hole, and smoothly pull out the cylinder; ② Use sling 3 and a hand chain hoist to fix the rotor lifting beam to the crane hook, lift the lifting beam, use the hand chain hoist to adjust the lifting beam to a horizontal position, and then adjust the crane position so that the hook is accurately aligned with the center of gravity of rotor 2. The whole process should be carried out slowly, while continuously adding lubricating oil to the jammed bearing to reduce friction damage during the separation process; ③ Secure the sling around rotor 2, and place a 5mm thick rubber plate at the rotor 2 hanging point to protect the surface of rotor 2 from scratches. Hook the sling to the corresponding hole of the rotor lifting beam; ④ Slowly lift rotor 2, closely observe the crane's load indicator, and when the displayed weight is equal to the weight of rotor 2 plus the weight of the single-sided bearing, the rotor 2 is lifted. When the weights are consistent, apply a uniform upward force to the joint where the bearing shells are bonded using a small crane. When the weight display shows that the weight is less than the weight of rotor 2 plus the weight of one side of the bearing shell, continue to lift slowly, keeping the weight stable, until the joint where the bearing shells are bonded is completely separated. ⑤ Slowly move rotor 2 to the already erected rotor support. The support points of the rotor support should be strictly in accordance with the equipment's accompanying data or maintenance manual to avoid uneven stress on rotor 2, which could lead to deformation. ⑥ After rotor 2 is removed, immediately cover all the openings of the casing with a dustproof cloth and seal all the pipe openings connected to the casing to prevent impurities from entering. At the same time, since the dry gas seal is a vulnerable component, it needs to be removed in advance. Insert wooden blocks wrapped in white cotton cloth into the sealing cavity to temporarily support rotor 2 and prevent rotor 2 from shaking and causing damage.

[0039] Step S8: Bearing and Cylinder Block Treatment The core purpose of this step is to repair damaged components and ensure that the bearings, bearing seats, and cylinder block meet the reinstallation requirements. The specific operation procedure is as follows: 1. Component Removal and Inspection: After hoisting rotor 2 onto the rotor support, smoothly remove the bearing assembly on the rotor support. Carefully inspect the bearing and bearing seat for damage, check for scratches and wear on the surface of rotor 2, accurately measure the diameter and roundness of the upper and lower bearing seats, check for deformation of the bearing seats, measure the fit dimensions between the bearing seats and the bearing slide, and record all measurement data in detail as the core basis for subsequent repair work.

[0040] 2. Grinding and Repair: Use a variety of files and sandpaper to finely grind and repair the damaged areas of the bearing seat, removing adhering impurities and surface burrs to make the bearing seat surface smooth and flat; evenly apply red lead powder to the bearing seat surface, place the lower bearing into the bearing seat for grinding, observe the grinding marks to find the high points of the bearing seat or bearing, and then carry out targeted repairs until the contact area between the bearing and the bearing seat reaches more than 85% to ensure that the fit accuracy meets the design requirements.

[0041] 3. Non-destructive testing: After the grinding and repair are completed, PT (penetrating penetration testing) non-destructive testing method is used to conduct a comprehensive and detailed inspection of the tilting pad, the inside of the pad seat, the outside of the pad seat, and the mating area of ​​the pad seat in the lower casing of the compressor to check for defects such as cracks and pores, and to ensure that the components are free of safety hazards; if defects are detected, further repair or replacement is required until they meet the relevant standards.

[0042] 4. Marking Management: After the bearing is removed, make clear and unique corresponding marks on the bearing and bearing seat to ensure that it can be accurately installed in the original position during reinstallation, and avoid subsequent unit operation abnormalities due to misinstallation.

[0043] Step S9: Component Reassembly The reassembly process must strictly follow the principles of "cleaning, assembly, positioning, and sealing" to ensure accurate installation and reliable sealing of each component. The specific operating procedure is as follows: 1. Cleaning process: Before reassembly, use a cleaning agent to thoroughly clean all components such as the bearings, bearing bases, machine casing, rotor impeller, and comb seals to remove surface oil, impurities, and grinding dust. After cleaning, wipe dry with a clean cotton cloth to ensure that the surface of the components is clean and free of residue, and avoid impurities affecting the fit accuracy and operational stability of the components.

[0044] 2. Component assembly: Accurately assemble the tilting tile and the tile shell, properly package and protect them, and place them in a designated area for later use to avoid damage to the components.

[0045] 3. Rotor reinstallation: Install the rotor support tool and dry gas sealing chamber, and slowly and steadily lift the rotor 2 back into the cylinder in the reverse order of rotor 2 removal, ensuring that the rotor 2 is in an accurate position and does not collide or interfere with the cylinder body or partition.

[0046] 4. Component installation: Install the axial bearing, dry gas seal, instrument line and radial bearing in sequence. During installation, take care to protect the surface of the components to avoid scratches and collisions, and ensure that each component is installed firmly and the gaps meet the design and equipment manual requirements.

[0047] 5. Cylinder head reinstallation: Clean the old sealant from the sealing surfaces of the upper and lower cylinder blocks. According to the preset ratio (8g of hardener CAT-RA to 1kg of sealant KE-20), put the hardener and sealant into a container and stir evenly for 10 minutes (until the container gets hot) to ensure that the two are fully mixed. Apply the mixed sealant evenly to the sealing surfaces of the cylinder block, ensuring that the coating thickness is uniform, without omissions or air bubbles. Before the sealant cures (within 5-6 hours), slowly lift the cylinder head back into its original position, reinstall it according to the markings and sequence during disassembly, and tighten all bolts to ensure a reliable cylinder block seal. Note that the hardener is a hazardous material, and safety precautions must be taken during operation.

[0048] Step S10: Acceptance Inspection After reassembly, a comprehensive acceptance test is conducted to ensure the unit can operate normally and stably. The specific operations are as follows: ① Recheck all clearance parameters such as radial bearing clearance, axial bearing clearance, and sealing clearance to confirm that all parameters meet the design requirements and equipment manual standards; ② Conduct a trial run of the unit, continuously observe the bearing operation, and check for any abnormal phenomena such as jamming, abnormal noise, or oil leakage; ③ Re-inspect key parts to ensure that no defects are missed, and that all performance indicators of the unit meet the standards, thus completing the entire bearing jamming treatment process.

[0049] The technical solution claimed by the present invention will be further described below with reference to a relatively specific embodiment.

[0050] This embodiment uses the scenario of the lower bearing of the NDE end of the low-pressure cylinder (LP) of an imported Mitsubishi ERC ethylene compressor unit as an example for illustration.

[0051] 1. Background: The compressor unit described in this embodiment is a dual-cylinder, five-stage horizontally split multi-stage centrifugal compressor. The low-pressure cylinder (LP) is model 9H-7S, with radial bearings using tilting pad bearings and thrust bearings using double-acting self-balancing tilting pad bearings. Under the on-site guidance of Mitsubishi experts, after installing the dry gas seal plate at the NDE end of the low-pressure cylinder (LP), the lower bearing was reinstalled. When the bearing was rotated to 2 / 3 of its position, it became completely stuck. An attempt was made to unscrew it using a 3-ton chain hoist and a 5-ton jack with added lubricating oil, but this did not achieve the desired effect, and there was an irreversible risk of rotor scratches and bearing damage. Therefore, all operations were stopped, and the method described in this invention was used to handle the situation.

[0052] 2. Processing procedure: Strictly follow the bearing jamming treatment method described in this invention, and perform the following steps in sequence: S1. Emergency Shutdown Procedure: Immediately stop all trial operations such as chain hoists and jacks, and record in detail the operating conditions at the moment of jamming (bearing bearing rotation angle approximately 60°, lubricating oil added, lubrication condition good), force parameters (chain hoist tension 3t, jack thrust 5t), and on-site environmental parameters (on-site temperature 25℃, humidity 60%), to provide a basis for subsequent analysis.

[0053] S2. Analysis of the Cause and Degree of Damage of Seizure: Through on-site investigation and data analysis, the core cause of this bearing seizure was determined to be the prolonged static placement of the unit (approximately 15 days), which led to slight deformation and adhesion of the material at the contact point between the casing and the bearing assembly. Simultaneously, insufficient clearance and inadequate lubrication during bearing reinstallation, coupled with subsequent external force, exacerbated the seizure, ultimately causing it to jam. Preliminary speculation suggests adhesion between the bearing and the casing, while no obvious damage was observed at the sliding contact point between the bearing and rotor 2.

[0054] S3. Determination of dismantling plan: The optimized dismantling plan of this invention is adopted. A small crane is made using channel steel and steel plate on site to apply a uniform upward force to the jammed part of the bearing, and the crane is used to lift the rotor 2 horizontally to avoid the rotor 2 tilting.

[0055] S4. Cylinder Block Bolt Removal: Prepare special tools such as a hammer wrench, bolt electric heater, and hydraulic torque wrench. Uniquely number the 24 cylinder block sealing bolts and create a heating record table. Set the hydraulic torque wrench pressure to 70MPa. Using the compressor axial centerline as the center line, heat the bolts simultaneously from front to back on both sides. Control the heating temperature at around 80℃. After heating for 30 minutes, loosen the bolts and make corresponding marks on the housing and nuts. After disassembly, neatly arrange the nuts in order.

[0056] S5. Cylinder head lifting guide: Assemble two guide rods, check that the surface is smooth and free of defects, apply lubricant, and install the guide rods at the left front end and right rear end positions of the cylinder head as required, ensuring that the installation is firm and the position is accurate.

[0057] S6. Cylinder head lifting: Clean the cylinder block surface and bolt holes of debris and dust, clean the set screws and apply lubricant, prepare the tooling and lay out the rubber sheet; the operator wears a one-piece work suit and properly keeps his personal belongings, using a 25t overhead crane, with two 10-ton slings for the front outriggers and two 10-ton hand-operated chain hoists for the rear outriggers to adjust the balance; use the set screws to test lift the cylinder head, check the balance of the sealing surface gap between the upper and lower cylinder blocks, and slowly lift it to a height exceeding the guide rod height, and place it stably on the tooling.

[0058] S7. Rotor Removal: Measure and record the clearances between the reflux diaphragm sealing ring and the bushing, the wheel cover and the sealing ring, the shaft seal clearance, and the radial and axial bearing clearances; determine the center of gravity and lifting point of rotor 2, place a 5mm thick rubber plate 4 at the lifting point, and install slings and lifting beams; continuously add lubricating oil to the jammed part of the bearing shell during lifting; when the crane's load indicator shows the same weight as rotor 2 plus the weight of one side bearing shell (approximately 18t), apply an upward force to the bearing shell adhesion point with a small crane; when the load indicator shows the weight drops to 17.5t, continue lifting slowly until the bearing shell is completely separated from the casing; smoothly lift rotor 2 to a special support, seal all openings and connecting pipes in the casing, remove the dry gas seal, and place a wooden block wrapped in white cotton cloth inside the sealed cavity to support rotor 2.

[0059] S8. Bearing and Cylinder Block Treatment: The bearing assembly was removed from the rotor support. Inspection revealed that the bearing was stuck to the housing. There were no scratches on the surface of rotor 2, and the bearing had no obvious damage. The diameter and roundness of the bearing seat were measured to confirm that there was no deformation. The stuck parts of the bearing seat were repaired by grinding with a mixed file and sandpaper. Red lead powder was applied and ground to make the contact area between the bearing and the bearing seat reach 88%. The tilting bearing, bearing seat and the mating part of the lower housing bearing seat were inspected using the PT non-destructive testing method. No cracks or other defects were found. Corresponding marks were made on the bearing and bearing seat.

[0060] S9. Component Reassembly: Clean all components, including the bearings, bearing seats, machine housing interior, rotor impeller, and comb seal, with a cleaning agent, and dry them for later use; assemble the tilting bearings and bearing shells, install the rotor support tool and dry gas sealing cavity, and reassemble rotor 2 according to the reverse procedure of rotor 2 removal; install the axial bearings, dry gas seal, instrument lines, and radial bearings in sequence; clean the old sealant from the sealing surfaces of the upper and lower cylinders, mix the sealant according to the ratio (8g of hardener CAT-RA to 1kg of sealant KE-20) and apply it evenly, and complete the reassembly and tightening of all bolts within 5 hours.

[0061] S10. Acceptance Inspection: Recheck all clearance parameters to confirm that they meet the design requirements and equipment manual standards; after 48 hours of trial operation, the bearings operate smoothly without jamming, abnormal noise, oil leakage or other abnormal phenomena, and all performance indicators meet the standards. The bearing jamming repair work was successfully completed.

[0062] Implementation Results: The process of handling the bearing jamming took 72 hours, which is 24 hours shorter than the solution proposed by the equipment manufacturer, and saves about 50,000 yuan in special tool processing costs. No damage was caused to core components such as rotor 2 and bearing during the process. The unit operated stably after the treatment, which verified the feasibility, reliability and economy of this method. It provides a real and referable practical case for handling bearing jamming incidents in similar large centrifugal compressor units.

Claims

1. A kind of construction method of bearing bush dead part processing of ethylene device ERC unit, bearing bush dead part is the contact part of shell and bearing bush assembly, it is characterized in that, include: Step 1: Number the sealing bolts of the compressor cylinder, heat the sealing bolts on both sides of the compressor in sequence, and after reaching the preset temperature, loosen and remove the sealing bolts; Step 2: First, use the set screw to test lift the cylinder head, check the gap between the upper and lower cylinder sealing surfaces to confirm the cylinder head is balanced, then use lifting equipment to lift the cylinder head and place it stably on a tooling that can bear the total weight of the cylinder head. Step 3: Install the upper and lower bearing assemblies onto the rotor shaft. Use a crane to apply an upward force to the jammed part of the bearing, and at the same time use a crane to lift the rotor horizontally. After the bearing assembly is completely separated from the lower housing, lift the rotor out of the cylinder and place it stably on the rotor support. Step 4: Remove the bearing shell from the rotor support and repair the damaged parts; Step 5: Reassemble the rotor and cylinder head.

2. The construction method for the bearing shell of the ERC unit of the ethylene plant according to claim 1, characterized in that: In step one, the heating temperature is 75–90℃.

3. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 2, characterized in that: In step one, a striking wrench and a hydraulic torque wrench are used together to loosen the sealing bolts, and the hydraulic pressure of the hydraulic torque wrench is controlled to not exceed 70MPa.

4. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 1 or 3, characterized in that: In step two, before lifting the cylinder head, a guide rod is installed on the frame at the left front end and right rear end of the cylinder head to limit the lifting path of the cylinder head. The surface of the guide rod is smooth and lubricated.

5. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 4, characterized in that: In step two, when lifting the cylinder head, the front outriggers are lifted using two 10-ton slings in conjunction with a 25-ton lifting device, while the rear outriggers are lifted using two 10-ton hand-operated chain hoists to adjust the balance.

6. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 1 or 5, characterized in that: In step three, during the rotor lifting process, lubricating oil is continuously added to the jammed parts of the bearing to reduce frictional damage during the separation process.

7. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 6, characterized in that: In step three, observe the crane's load indicator during lifting. When the displayed weight is consistent with the weight of the rotor plus the weight of the single-sided bearing shell, apply an upward force to the joint where the bearing shell is stuck together to keep the load stable. After the joint is separated, lift the rotor to the rotor support.

8. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 1 or 7, characterized in that: In step four, when repairing the damaged parts, use a mixed file and sandpaper to grind and repair the damaged parts of the bearing seat. Place the lower bearing into the bearing seat coated with red lead powder and grind it to repair the high point so that the contact area reaches more than 85%.

9. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 8, characterized in that: In step five, the components such as the bearing blocks, bearing seats, the inside of the casing, the rotor impeller, and the comb seal are cleaned before reassembly.

10. The construction method for handling the jammed bearing of the ERC unit of an ethylene plant according to claim 9, characterized in that: In step five, after reassembly, apply sealant to the sealing surfaces of the upper and lower cylinders. The sealant is prepared by mixing CAT-RA curing agent and KE-201Kg sealant at a mass ratio of 8:1000. After stirring evenly, apply the sealant and complete the cylinder head reassembly and bolt tightening within 5 to 6 hours.

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