Liu Yu

(Sinopec Maoming Branch, Maoming, Guangdong 525000)

[Abstract] : The ultra-high pressure reciprocating compressor of a certain high-pressure device has repeatedly experienced radial leakage of packing, which not only affects the normal operation of the device but may also lead to the occurrence of safety accidents. An in-depth study was conducted on the radial leakage problem of packing. The aim was to comprehensively analyze all aspects of the radial leakage problem of packing. By analyzing factors in multiple aspects such as the mechanical properties of packing, fatigue mechanism, residual stress of packing, original design Angle of packing tray, process operation, equipment inspection and maintenance, and selection of lubricating oil, the main causes of the leakage problem were identified. Based on this, a series of improvement measures and suggestions have been proposed. By comprehensively applying theoretical analysis, on-site investigation, experimental verification and other methods, a systematic and scientific analysis framework will be formed, providing theoretical support and practical guidance for solving similar problems. This includes the introduction of a compressive stress layer and silver plating process on the packing tray, quality control of packing tray design and manufacturing, standardized operation and maintenance management, and strengthened quality control of maintenance, etc.

[Key words] : Ultra-high pressure reciprocating compressor Radial leakage of packing; Fretting wear Improvement measures

Chinese Library Classification Number: TH457 Document Code: B

Article Number: 1006-2971 (2025) 04-0047-06

1 Introduction

A certain ultra-high pressure reciprocating compressor has been stably operating for 28 years since it was put into use in 1996. This compressor adopts a two-stage compression design, with a working pressure as high as 220 to 250MPa and a design pressure reaching 269MPa. It is equipped with 8 cylinders (4 first-stage cylinders and 4 second-stage cylinders) to achieve efficient compression of ethylene gas.

1.1 Principle of Packing Seal for Ultra-High Pressure reciprocating Machine

Packing seal devices are a commonly used sealing form in industrial equipment and are widely applied to the shaft end sealing of rotating or reciprocating motion in pumps, compressors, etc. Its working principle mainly relies on the elastic-plastic deformation of the packing material under axial pressure, as well as the frictional force and lubrication effect between the packing and the shaft surface, thereby achieving the purpose of preventing medium leakage.

Specifically, a packing seal device is typically composed of components such as a packing disc, packing ring, and packing gland. Packing rings are usually made of fibrous, braided or formed sealing materials, such as asbestos, graphite, polytetrafluoroethylene, etc. However, the seal between the cylinder and the packing disc of the ultra-high pressure compressor discussed this time adopts a direct metal-to-metal contact sealing method. The packing material is copper alloy, and the sealing surface is flat. The surface is ground to ensure reliable sealing and guarantee the stable operation of the compressor. The dynamic sealing packing of the plunger is sealed with a three-petal or six-petal packing ring made of copper alloy. The three-petal or six-petal packing ring is installed in the packing tray.

There are a total of 9 packing discs in this compressor. From the outside to the inside, they are discs 0 to 8. Among them, discs 1 to 6 are equipped with packing rings, which mainly perform sealing operations. Support rings are installed inside tray No. 7. Guide rings are installed inside tray No. 8.

Due to the reciprocating motion between the plunger and the packing ring, a lubricating oil hole is designed to inject lubricating oil for lubrication. To remove the frictional heat from the packing ring and the plunger, a cooling system is set up for cooling to control the frictional heat and temperature rise. The packing disc and the cylinder are connected by six large bolts. The tightening force of the bolts not only serves as the sealing pressure for the sealing surfaces of the packing disc and the cylinder but also functions as a rigid support.

1.2 Introduction to Radial Leakage of Packing in Ultra-High Pressure Reciprocating Compressors

This unit was put into use in 1996 and has been in operation for 28 years by 2024. During operation, the surface of the packing disc of this machine often experiences problems such as wear and leakage, and sometimes even cracks occur. This not only leads to the scrapping of compressor components like the packing disc but also poses a threat to the safe operation of the compressor. The worn area of the packing tray is located on the inner side of the packing tray. After the metal on the surface of the worn area wears off and peels off, small pits are formed, but the pits are relatively shallow, and there are a few fine particles on the worn surface. Taking the packing disc that cracked in April 2024 as an example, radial ethylene leakage occurred in the packing. At that time, the operating pressure was as high as 227MPa. To ensure safety, the device was urgently shut down for handling. During the process of disassembling the 9 packing discs for maintenance, it was found that there was a crack on the sealing surface between Disc No. 1 and Disc No. 2, which led to ethylene leakage into the cold stamping oil. The worn area of the packing disc is located 57mm near the inner diameter on the inner side of the packing disc, while the other areas of the sealing surface of the packing disc remain intact without any wear marks. The crack is located on the end face of the packing disc and has penetrated the entire thickness of the packing disc. Its morphology is similar to that of the packing discs worn and cracked by this machine over the years.

Analysis of the Causes of Radial Leakage in the Packing of the Ultra-High Pressure Reciprocating Machine

For this malfunction, a thorough investigation was conducted on the possible causes one by one: analyzing multiple factors including the mechanical properties of the packing, fatigue mechanism, residual stress of the packing, process operation, equipment inspection and maintenance, selection of lubricating oil, and maintenance level.

2.1 Analysis and Exploration of Mechanical Properties of the Packing Tray

2.1.1 Macroscopic Observation

Through macroscopic observation of the No. 1 packing tray, the following key information can be obtained. Firstly, there are obvious erosion pits on both the front (inner side) and back (outer side) of the packing tray, which indicates that the packing tray has undergone severe wear during use. Parallel wear marks appeared in the back pits, indicating that there was relative sliding between the packing disc and the adjacent packing discs or cylinder liners, which exacerbated the wear. The crack is located at the edge of the eroded area and extends to both sides, with a length of approximately 180mm, and has axially penetrated the entire wall thickness. This indicates that the cracks gradually formed under long-term wear and stress. The crack was planed open to observe the macroscopic morphology of the fracture surface. It was seen that the crack started from the abrasion pit on the back, and the radial lines of the original crack origin could be observed. The fracture surface is smooth, and fatigue streaks and rolling marks can be observed. Therefore, based on the macroscopic morphology, it is initially speculated that the crack of the packing disc is a fatigue crack that originated from the erosion pit on the back.

2.1.2 Chemical Composition Analysis

After conducting a chemical composition analysis on the sample packing tray, detailed elemental content data were obtained, as shown in Table 1.

The analysis results show that the chemical composition of this packing tray fully complies with the composition requirements of 30CrNiMo8 (1.6580 high-strength steel) in the EN10083-3 standard. In conclusion, the chemical composition of this packing tray meets the standard requirements, providing a foundation for its excellent mechanical properties and corrosion resistance.

2.1.3 Mechanical property and hardness testing and analysis

Detailed mechanical property and hardness testing and analysis were carried out on the incoming packing discs. The results of the mechanical property test at room temperature show that the tensile strength, yield strength, elongation after fracture and impact energy of the packing disc all meet the requirements of 30CrNiMo8 (1.6580 high-strength steel) in the EN10083-3 standard. Specifically, the yield strength is between 918 and 960MPa, the tensile strength is between 1027 and 1058MPa, the elongation after fracture is no less than 18.0%, and the average impact energy reaches 98J, which is much higher than the 45J stipulated by the standard. These data indicate that the packing tray has good mechanical properties at room temperature, with sufficient strength and toughness.

However, the hardness test results show that the hardness of the packing tray material is lower than the lower limit of the required value of 30CrNiMo8 in the EN10083-3 standard, especially the hardness near the surface is approximately 130HB lower. However, by comparing the hardness measurement values of the cracked packing disc and the uncracked packing disc, it was found that the hardness values of the two were comparable. Therefore, it is impossible to infer whether the hardness being lower than the standard value is the main cause of the cracking of the packing disc. These data indicate that the hardness of the packing tray remains at a similar level regardless of whether it has cracked or not.

2.1.4 Metallographic analysis

An in-depth analysis was conducted on the metallographic structure of the sample packing tray. The metallographic structure of the packing disc material shows the characteristics of tempered sorbite structure with martensite orientation. This structure is a typical one of 2Cr13 material after quenching and tempering treatment, indicating that the packing disc material has achieved the expected effect in the heat treatment process.

Further observation of the metallographic morphology of the crack reveals that it exhibits the feature of transgranular propagation, which usually indicates that the crack has encountered significant resistance during the propagation process, leading to the crack proceeding along the grain boundaries or through the interior of the grains. In addition, corrosion products were found at the crack tip, mainly including sulfides, oxides and carbides. The presence of these corrosion products may have accelerated the crack propagation rate and had an adverse effect on the material's performance.

It can be inferred that the heat treatment process of the packing tray material is reasonable. However, the existence of cracks and their propagation characteristics indicate that the material may have been subjected to the combined effects of complex stress states and corrosive environments during its use, leading to the formation and propagation of cracks. Therefore, it is necessary to pay close attention to the influence of material stress and corrosion on the generation of cracks.

Analysis and exploration of the mechanical properties of the packing disc reveal that this crack is a fatigue crack. The mechanical properties of the packing disc indicate that its hardness is lower than the standard value and it has been subjected to the combined effects of complex stress states and corrosive environments.

2.2 Research on the Generation Mechanism of Fatigue Cracks in Packing Discs

The principle of fatigue crack generation is that as the compressor repeatedly sucks in and exhauffles, there is relative sliding between the packing disc and the adjacent packing disc or cylinder liner end face. The metal on the end face (sealing surface) undergoes fretting wear and fretting fatigue, resulting in defects such as particle spalling, wear and wrinkles on the contact surface. Secondly, fatigue cracks first emerge at these defect sites, becoming crack precursors. Under the action of alternating loads of the compressor, they continuously expand axially and on both sides, eventually penetrating the wall thickness of the packing tray and becoming through cracks.

According to the working principle of packing seals, during the normal operation of the compressor, due to the different radial pressures (Figure 1) between two adjacent packing discs, under the action of internal pressure, the strains produced by the two adjacent packing discs are different because they are subjected to different pressures. When the compressor sucks air, the pressure on the left packing disc close to the cylinder is greater than that on the right packing disc, and the deformation of the left packing disc is greater than that of the right packing disc. The resulting deformation is shown by the solid line in Figure 2. When the compressor exhautes, the cylinder pressure rises, and the internal pressure on the packing disc also increases. The deformation of adjacent packing discs further increases. However, due to the different increases in internal pressure, the deformations of the two packing discs are still different. The displacement of the left packing disc is greater than that of the right packing disc. The deformations of the two packing discs are shown by the dotted lines in Figure 2. As a result, relative sliding occurs between the packing discs. Since the reciprocating compressor constantly sucks in and discharges air, the pressure inside the cylinder rises and falls periodically. Therefore, the surfaces of adjacent packing discs are constantly sliding and rubbing against each other during the operation of the compressor. As the compressor cylinder moves repeatedly, the contact surface of the packing disc will suffer from wear damage and wrinkles and other defects. The above situation is called fretting wear. The degree of wear damage is related to parameters such as clamping force and material hardness. The greater the clamping force and the insufficient material hardness, the greater the degree of damage. Therefore, based on the analyzed data, the packing compression force is one of the reasons affecting the surface erosion and fatigue cracking of the packing disc, which may accelerate the wear and damage rate of the packing disc sealing surface.

By exploring the generation mechanism of fatigue cracks in this packing disc, it is demonstrated that the crack mechanism falls within the category of freading wear, and it is inferred that the packing compression force affects one of the reasons for the fatigue cracks on the surface of the packing disc.

2.3 Residual Stress detection of the packing tray

The residual stress of the packing tray was investigated. According to the residual stress detection report, the surface compressive stress on the inner side of the packing cup was far lower than the standard value of -260 to -350 mpa, with the lowest reaching only -113 mpa.

Especially for the No. 1, No. 2 and No. 3 discs, due to the large number of oil holes, the residual tensile stress is concentrated near the edges of the oil holes. This is very likely to cause surface cracking of the packing discs in high-pressure operating environments. According to historical maintenance records, the frequent cracking of the No. 1, No. 2 and No. 3 discs is related to the large number of oil holes and the easy accumulation of residual tensile stress. When the residual compressive stress is insufficient, the mechanical properties of the packing tray are extremely prone to failure, leading to surface cracking that gradually deepens, and eventually causing radial leakage and device shutdown. Each cracking occurred in the area between the oil hole and the packing tray, further confirming the influence of residual tensile stress concentration on the cracking of the packing tray.

The detection of residual stress in the packing tray confirmed the influence of residual tensile stress concentration on the cracking of the packing tray.

2.4 Analysis of the original design and manufacturing perspective of the packing tray

Through multiple discussions with the original design manufacturer of this compressor, it has been found that the packing disc cracking problem that has repeatedly occurred over the past two decades of use has been documented. Since 1996, there have been more than 20 instances of packing disc cracking causing shutdowns. Similar packing disc cracking issues have also occurred in 2016, 2017, 2020, and 2023. One of the initial inferred reasons is the original design issue. The packing disc is designed to be too thin, with a thickness of only 41mm. In contrast, the packing disc thickness of similar Bookhard compressors of the same pressure rating but different brands reaches 56mm. The packing disc thickness of the New Bilon is only 73% of that of the Bookhard compressor. Moreover, the manufacturing quality of the packing tray is unstable, with structural deviations such as insufficient hardness, local defects, and insufficient parallelism, as well as unstable quality reasons like microscopic pores caused by metallurgical technology and stress resulting from lubricating oil opening, which lead to cracks under fretting wear conditions.

2.5 Analysis of Other Influencing Factors of Packing Tray Cracking

Analyze other fault causes that affect the cracking of the packing tray, which are classified into process operation reasons, packing installation, plunger wear, whether the internal oil and cold stamping oil are sufficient, and the selection of lubricating oil, etc. Check and analyze them one by one.

2.5.1 Process operation issues

The process operation status of ultra-high pressure reciprocating compressors has a significant impact on the service life of packing. Fluctuations in suction and exhaust pressures can accelerate the wear of packing rings and cause cracking of packing discs. Improper process operation is a cause that cannot be ignored. In the actual production process, the skill level of the operators, their maintenance awareness, and the standardization of the process operation procedures will all directly affect the operational effect of the packing seal. Insufficient skill levels of operators may lead to improper operation.

If the operation is not carried out in accordance with the prescribed procedures during the start-up and shutdown process, grade switching or voltage increase and decrease process, or if there is insufficient understanding and judgment of the operating status of the equipment, it may lead to damage to the packing seal system or the occurrence of leakage problems.

Investigating this malfunction, the exhaust working pressure of the compressor was 227MPa and the working temperature was 88℃. Checking the DCS, no production adjustments were made before the incident occurred, and the medium temperature, pressure and flow rate were stable. The influence of process operation issues on this malfunction can be ruled out.

2.5.2 Packing installation issues

The standardization of the packing installation and maintenance process is also an important factor affecting the operation effect of the packing. If the maintenance process is not standardized or not implemented properly, it may lead to damage to the packing during the repair process or prevent it from being fully repaired. If the operation is not carried out in accordance with the prescribed steps when replacing the packing, or the adjustment of the tightening force of the packing bolts is inaccurate, etc.

The packing disc and the cylinder are connected by six cylinder head packing fastening bolts. The fastening force of the bolts provides the sealing pressure between each packing disc and the sealing pressure of the cylinder sealing surface. Therefore, in combination with structural analysis, the clamping force of the packing is the key factor affecting the fretting wear on the surface of the packing disc. According to the principle of fretting wear, excessive clamping force of the packing can accelerate the rate of wear and damage to the sealing surface of the packing disc. If the packing fastening force is too small, it will cause insufficient preload on the sealing surface of each disc, resulting in loosening and wear damage to the sealing surface.

To investigate this malfunction, the maintenance unit assembled the spare cylinder head strictly in accordance with the requirements of the original factory manual of Xinbilong. They used the matching tensioner to install the packing fastening bolts and valve fastening bolts of the cylinder head. The installation of the packing fastening bolts of the cylinder head corresponds to the oil pressure of 1000bar of the tensioner oil pump. Install the valve fastening bolts corresponding to the oil pressure of the tensioner oil pump at 1100bar. It can ensure that the pre-tightening force required for each disc of the packing is neither too large nor too small, and can eliminate the influence of packing installation problems on this fault.

2.5.3 Plunger wear issues

The plunger of the ultra-high pressure reciprocating machine is the main working component for compressing gas. When it moves back and forth under the drive of the crosshead, the volume of the working chamber changes periodically, achieving the suction, compression and discharge of gas. The plunger is made of solid tungsten carbide, a wear-resistant and high-strength material, and has relatively high installation requirements. If the plunger wears out severely during operation and has too many burrs on its surface, it will cause damage to the packing ring and packing disc.

Disassembly inspection was carried out to explore this fault. It was confirmed that the plunger of the faulty packing had no burrs, cracks or defects and could continue to be used, thus minimizing the impact on this fault.

2.5.4 Insufficient oil inside the packing and cold stamping oil

Due to the reciprocating motion friction between the plunger and the packing ring and the generation of heat, an lubricating oil hole is designed. Lubricating oil is injected for lubrication and then enters the system to mix with ethylene. This part of the oil is called internal oil. To remove the heat generated by the friction between the packing ring and the plunger, a circulating cooling system is set up for cooling to control the frictional heat and temperature rise. This part of the oil takes away the heat through the heat exchanger and is called cold stamping oil.

The lack of maintenance awareness may also lead to untimely or inadequate maintenance of the packing oil system. If sufficient attention is not paid to the filling of internal oil and the management of cold stamping oil, the performance and reliability of the packing seal system will be reduced. Insufficient or interrupted internal oil and cold stamping oil of the packing will accelerate the damage of the packing ring and packing tray. Insufficient internal oil will be manifested as the packing ring that continuously rugs against the plunger turning black or even breaking and damaging. During this disassembly, it was found that the packing ring corresponding to the cracked packing disc did not show obvious blackening or damage. Therefore, this cause can be ruled out this time. Insufficient cold stamping oil is manifested in the drop of cold stamping oil pressure, the absence of the oil return sight glass, and the obvious blackening of the outer cavity of the packing disc. This disassembly and actual on-site inspection did not show such situations, so this cause can be ruled out this time.

2.5.5 Improper selection of packing lubricating oil

If the internal oil selected is inappropriate, it will lead to an increase in the friction between the fillers, accelerating the wear and aging of the fillers. Improper selection of cold stamping oil can prevent heat from being carried out and, when it comes into contact with the sealed packing tray, it is prone to corrosion. For instance, in the No. 2 high-pressure unit of Maoming Petrochemical, a similar compressor once experienced a situation where the packing disc cracked due to corrosion caused by improper selection of cold stamping oil. Through corrosion tests, it was confirmed that the domestic cold stamping oil used at that time contained additive substances with a strong tendency to form scale. Crevice corrosion or under-scale corrosion occurred at the bottom of the double-pointed grooves at the top of the outer end of the filler positioning bolt holes and the corner positions of the bottom grooves. The corrosion pits formed became the crack sources for fatigue cracking and fatigued expanded under the action of alternating loads until they broke. Thus, it can be inferred that the corrosion of cold stamping oil is the main factor causing the fracture of the packing tray. However, no corrosion or problems were found in this fault investigation. The influence of improper selection of packing lubricating oil on this fault can be ruled out.

3 Improvement measures and suggestions

In response to the radial leakage problem of the packing in this ultra-high pressure reciprocating machine, the following improvement measures and suggestions are proposed, aiming to solve the leakage problem from the source and enhance the operational efficiency and safety of the equipment.

3.1 The packing tray introduces a compressive stress layer and a silver plating process

The working principle of introducing the compressive stress layer: By forming a stamping on the surface of the workpiece to create a compressive stress layer, the original tensile stress left on the surface layer of the workpiece due to mechanical processing is removed, forming a uniform compressive stress layer. When the layer depth is 0.4 to 0.6mm, the compressive stress value can be increased to the range of -400 to -580 mpa.

By using the Proto-LXRD X-ray stress analyzer, the data before and after the introduction of the compressive stress layer into the packing tray were compared. It was concluded that the residual compressive stress on the surface of the workpiece after the introduction of the compressive stress layer was improved, with an average increase

Appreciation: 210% - 220%.

The sealing surface of the packing tray is treated with silver plating, which can form a silver layer of 0.01 to 0.02mm, effectively preventing rust and oxide layer formation on the sealing surface. The hardness of the silver layer is 50HV, which is far lower than the hardness of the packing disc sealing surface itself, forming a "soft sealing layer". When the sealing surfaces on both sides of the odd-numbered disc and the even-numbered disc come into contact, the soft sealing layer of the odd-numbered disc and the hard sealing surface of the even-numbered disc are tightly pressed by the pre-tightening force to form a microscopic geometric deformation, which can greatly improve the fit of the two contact surfaces and at the same time avoid the direct contact of the two rigid hard sealing surfaces, thereby preventing freading wear.

To address this issue, measures such as beveling and chamfering are adopted to release residual stress, as well as the introduction process of the compressive stress layer and silver plating technology proposed by ExxonMobil, to enhance the mechanical properties of the packing tray and reduce fretting wear on the sealing surface. When purchasing new packing discs and other components, these two technologies will be adopted to increase the residual compressive stress in the packing disc area, reduce or even avoid the cracking of the packing disc, and extend the operating time of the packing.

3.2 Quality Control of Packing tray Design and Manufacturing

We communicated with the original design manufacturer of this compressor, Xinbilong, to tackle the problem from the design perspective. By reducing the number of packing discs, the thickness of the packing discs was increased. The specific plan was to reduce one disc from No. 1 to No. 6 and replace it with five discs containing packing rings. According to the design, the sealing effect was feasible. The thickness of each packing disc was increased from 41mm to 49mm. Increase by 20%, significantly enhancing the stability of the packing tray in use and preventing it from cracking.

In addition, in response to the unstable manufacturing quality of the packing discs produced by manufacturers, it is required to strictly control the quality, optimize the heat treatment process or surface treatment process of the packing discs, and enhance the hardness of the end face (sealing surface) of the packing discs. By ensuring the hardness requirements of 30CrNiMo8 as stipulated in EN10083-3 standard, eliminating structural deviation issues such as local defects and insufficient parallelism, and controlling the occurrence of microscopic pores and lubricating oil opening caused by metallurgical technology

The unstable quality problems such as stress generated ultimately lead to the cause of fretting wear and cracks.

3.3 Standardize operation, maintenance and management

The skill level of the operators of ultra-high pressure reciprocating compressors, their maintenance awareness, and the standardization of the process operation procedures will all directly affect the operation effect of the packing seal. Establish a regular training and assessment mechanism to ensure that operators always possess the corresponding professional skills and knowledge. Refine and optimize the operation procedures and processes of the equipment to ensure that the operation steps are clear and explicit, and avoid equipment damage or leakage problems caused by operational errors. Establish a feedback mechanism for operating procedures, promptly collect the opinions and suggestions of operators, continuously optimize the operating procedures and processes, the start and stop process of compressors, the process of grade switching or pressure increase and decrease, and operate in accordance with the prescribed procedures and plans. Set up communication channels and collaboration mechanisms among operators, enhance their maintenance awareness, be able to maintain and service, and troubleshoot. Have a sufficient understanding and judgment of the operation of the equipment, encourage operators to actively participate in the improvement and optimization of the equipment, and jointly enhance the operational efficiency and safety of the equipment. Through the above-mentioned management measures, any damage to the packing caused by process operations and production adjustments can be avoided.

3.4 Strengthen the quality control of maintenance

One of the reasons for the fatigue cracks on the surface of the packing disc is deduced from the principle of fretwork wear. It is required that the construction unit strictly carry out maintenance and repair in accordance with the requirements of the manual, and install the cylinder head packing fastening bolts corresponding to the oil pressure of the tensioner oil pump 1000bar. Install the valve fastening bolts corresponding to the oil pressure of the tensioner oil pump at 1100bar. And strictly control the tightening torque of each cylinder bolt to ensure uniformity to prevent uneven tension.

Establish a quality control table for cylinder maintenance, set quality standards for each quality control point, and have professional equipment managers check, confirm and sign. All professional managers are well-versed in professional knowledge and jointly supervise, inspecting and accepting each step of the construction process to enhance the quality management of maintenance and repair.

4 Conclusion

This paper conducts in-depth research on the problem of repeated radial leakage of packing in ultra-high pressure reciprocating compressors from both micro and macro perspectives and draws the following conclusions:

Through a comprehensive analysis of the radial leakage problem of the packing and an exploration of the mechanical properties of the packing disc, it can be known that the cracks causing the radial leakage of the packing belong to fatigue cracks.

(2) By exploring the fatigue crack generation mechanism of this packing disc, it is demonstrated that the crack mechanism belongs to fretting wear.

(3) Residual tensile stress concentration and design and manufacturing quality issues of the packing tray are the main causes of fatigue cracks. Analyze other fault causes that affect the cracking of the packing tray, which can be classified into process operation reasons, packing installation, plunger wear, whether the internal oil and cold stamping oil are sufficient, and the selection of lubricating oil, etc.

On this basis, a series of improvement measures and suggestions were proposed, including introducing a compressive stress layer and silver plating process to the packing tray, quality control in the design and manufacturing of the packing tray, standardizing operation and maintenance management, and strengthening quality control in maintenance, etc.

The implementation of these measures is expected to fundamentally solve the problem of radial leakage of packing in ultra-high pressure reciprocating compressors, enhance the safety and stability of the equipment, and also provide useful references and guidance for other petrochemical enterprises.