A bolt on the channel head flange of the feed heat exchanger in an S-Zorb unit fractured at a refinery.To identify the cause of the bolt failure and fracture, thereby formulating effective protective measures to prevent disruption to normal production and ensure operational safety of the equipment, an indepth investigation was conducted through macroscopic inspection, material composition analysis, mechanical property testing, metallographic examination, scanning electron microscopy (SEM), and energydispersive Xray spectroscopy (EDS) analysis.The results indicate that the fracture surface of the bolt presents a quasicleavage morphology. It is therefore concluded that the bolt fracture occurred due to the following causes: insufficient heat treatment led to a coarse and unevenly distributed grain structure in the metallographic microstructure. After prolonged service, component segregation occurred within the alloy, which resulted in reduced hardness and impact toughness of the base material.In addition, prolonged exposure to stress concentration in the fracture region resulted in fatigue crack initiation. Under the action of tensile stress and torque, brittle fracture occurred. Based on the above analytical findings, restorative heat treatment should be implemented for the bolts, specifying appropriate thermal processes to refine the grain structure, thereby improving the mechanical properties of the material.

Dry gas holder is a widely used gas storage container in China, and the use of rubber sealing film on dry gas holder directly affects its maintenance cycle and operational safety. Through the analysis and research on hydrogenated nitrile rubber sealing film of dry gas holder in a refinery, it is found that hydrogen sulfide reacted with hydrogenated nitrile rubber sealing film after six years of operation of dry gas holder under the condition that the medium contained hydrogen sulfide, resulting in the decline of tensile strength, elongation at break, hardness and other properties of the sealing film. In addition, it is also found that if the dry gas holder is operated in a certain height range for a long time, the adhesive material in the joint of the rubber sealing film will first crack and age. Aiming at the above phenomenon, a research was conducted on dry gas holders within the industry. And the results indicate that the less corrosive the dry gas holder medium is, the more favorable it is for the longterm operation of the rubber sealing film.

Taking the actual operating parameters of the device as an example, this paper explained in detail the specific method of process calculation for the main fan and flue gas turbine unit of the catalytic device through thermodynamic methods. It also proposed a specific calculation process for calculating the theoretical power of a flue gas turbine through energy balance. The theoretical power of the main fan and the flue gas turbine were calculated using universal calculation formulas and process simulation tools. The results show that the two algorithms are close with a deviation of less than 1%. The design regulations of process simulation tools can be used to calculate the actual flue gas flow rate of the flue gas turbine, correct the insulation efficiency of it, and obtain the distribution ratio of regenerated flue gas through the flue gas turbine, double acting slide valve, and threestage rotary separation critical nozzle. Based on the above calculation results, the feasibility of measures such as increasing the proportion of flue gas entering the flue gas turbine, increasing flue gas temperature, and reducing regeneration pressure under low load operating conditions was evaluated, and targeted optimization plan was proposed.

Lowtemperature multieffect seawater desalination device needs to operate in a negative pressure environment, so the design of the vacuum system is crucial for the stable and safe operation of the device. This paper introduces the working principle of the injector and establishes a calculation method for the vacuum system pumping volume and multistage injection. Combined with a practical engineering case, the steam consumption and equipment process parameters under different injection process flows are calculated in detail and analyzed. This provides theoretical and computational basis for the process design and scheme selection of the vacuum system of the lowtemperature multieffect seawater desalination device.

Urban natural gas purification plants are crucial infrastructure for socioeconomic development and energy structure optimization. However, the noise issues arising during the operation of urban natural gas purification plants pose a threat to occupational health and the surrounding residents. In this paper, the current situation of noise pollution in urban natural gas purification plants is introduced; and the source intensity, frequency characteristics and propagation influence of the main equipment noise are analyzed. Based on the actual noise levels of equipment at urban natural gas purification plants after commissioning, this paper focuses on analyzing targeted noise control measures and their corresponding noise reduction effects for noise sources identified onsite, and provides insights into future noise control strategies along with relevant recommendations. The analysis and recommendations presented herein can serve as a reference for similar engineering designs.

The feed gas compressor of a 140,000 m3/h (standard state) hydrogen production & PSA unit is a 2D12591/639BX reciprocating compressor manufactured by Shenyang Blower Works Group Corporation. During its operation, the settlement displacement monitoring probe on the secondary piston rod is prone to contact wear with the piston rod, resulting in frequent replacement of the displacement monitoring probe and the compressor is therefore unable to operate continuously for a long period of time. During a recent replacement of the monitoring probe, it was found that the secondary piston rod was in contact with the inner ring of the middle body stuffing box cover, causing damage to both the upper surface of the piston rod and the inner ring of stuffing box cover due to friction. After disassembling the compressor for inspection, two problems were found: one is that the horizontal inner diameter of the middle position of the secondary cylinder liner deviates too much from the standard value, resulting in too small the gap between the middle support ring of the piston and the inner wall of the cylinder liner; and the other is that the overall tilt of the secondary cylinder and the crosshead slide exceeds the standard value. Aiming at the above problems, three measures for improvement were proposed, namely, replacing the secondary cylinder liner, readjusting the tilt amount of the secondary cylinder during installation, and periodically flushing the cooling jacket of the cylinder with clean water at a slightly higher pressure. After taking these measures, the monitoring data of the compressor has been back to normal and the operating condition has been good.

When the radiant furnace tubes of the ethylene cracking furnace operate for a long time under severe working conditions, the failure mechanism involves tube carburization, bulging deformation, crack fracture, etc.; the bulging phenomenon of the tubes is more obvious in cracking furnaces with gasphase feedstock.With the occurrence of furnace tube bulging, the risk of penetrating cracks in the furnace tube is elevated, which could lead to emergency shutdown of the unit. In order to effectively mitigate such risks, one petrochemical company employed an intelligent inspection system to carry out comprehensive crawling inspections on furnace tubes during cracker maintenance and for the first time obtained the surface information such as bulging data for the entire domain of the furnace tubes in service for ethylene cracking in the industry.Through a crossanalysis of furnace tube bulging and carburization data, the close correlation between bulging and carburization is further validated. In addition, the above inspection data can be utilized to optimize production process parameters and prepare datadriven plans for furnace maintenance and tube replacement, providing data support for enhancing production efficiency and reducing shutdown risks.

Aiming at the local deformation of the bottom plate and cracking of the storage tank foundation caused by overpressure in a petrochemical enterprise's lowpressure storage tank, theoretical calculations and finite element failure methods were adopted to conduct reliability analysis of the tank body and foundation, and determine the best repair plan. The study showed that due to the storage tank foundation's ring wall structure with a sandfilled core, the deformation was localized at the bottom plate while the wall plate remained deformationfree. Thus it was judged that the tank was basically reliable, and the focus was on repairing the bottom plate and foundation. Partial replacement of the bottom plate was adopted, and the asphalt sand layer in the middle of the foundation was filled with highpressure grouting. The ring wall foundation was reinforced to evenly distribute the force on the bottom plate. After repair, nondestructive testing was conducted on the bottom plate and the foundation strength was rechecked, both of which met the operational requirements. The storage tank has been operating smoothly for one year without any abnormalities.

During the normal operation of the steam turbine of a natural gas compressor unit of a synthetic ammonia plant with an annual output of 450,000 t, the opening signal of the speed control valve output by the control system shows a gradual decline. However, the actual opening position of the steam turbine control valve and its rotational speed remain stable, while the compressor discharge pressure remains within normal range without abnormal fluctuations. Based on the working principle of the speed control system of the steam turbine, the relevant systems and components of the unit were investigated. It was determined that the gradual decline in the elasticity of the inner spring of the pilot valve or the wear of the hydraulic servomotor feedback rod components was the main reason for the continuous slow decline in the speed control valve opening signal of control system of the steam turbine. And the wear of the needle roller bearing on the hydraulic servomotor feedback rod was found in the subsequent maintenance, which has validated the accuracy of the fault cause analysis.The hydraulic servomotor that was replaced during previous maintenance and repaired for backup use was reinstalled and commissioned. Over prolonged operation, the speed control valve opening signal of the control system has remained stable and no abnormal changes have occurred.

This paper introduces the current status of sealing performance testing standards for commonly used nonmetallic gaskets at home and abroad. And a new type of low leakage sealing gasket with chemical resistance made by reinforced polytetrafluoroethylene was tested for leakage rate through simulation of flange surface defects. The low leakage sealing performance of this type of gasket for pipe flange systems was verified. The above test resultsshow thatthe new reinforced polytetrafluoroethylene sealing gasket can provide a sealing option for plant pipework with a higher level of safety and in more severe operating conditions.

This paper introduces the continuous development, innovation and practice of the Total Productive Maintenance (TPM) equipment management training project system. Guided by the theory of integration of training and practical application, the "ThreeTiered" TPM training series program was designed. This is achieved through hierarchical and gradient planning for three target groups: TPM promoters, TPM key personnel, and TPM elites.This training program has systematically and continuously explored and implemented the threephase structure consisting of theoretical learning, onthejob practice and summary presentations. The "ThreeTier and ThreePhase" framework for the TPM equipment management training was innovatedand the "pyramid" model of the TPM equipment management training project system was constructed.This model facilitates the continuous deepening and effective implementation of TPM lean management and 5S workplace organization within enterprise production systems.

After the gas storage well was put into production, it has undergone multiple cycles of injection and production and has been subjected to longterm alternating load changes. Pressure buildupmay occur in the oil pipe and oil sleeve annulus, oil sleeve and technical sleeve annulus, and technical sleeve and gauge sleeve annulus; meanwhile, longterm exposure to high pressure in various levels of the annulus can easily damage the integrity of the wellbore seal, causing natural gas injection leakage. This may affect well control safety and normal production. There are over a dozen reasons that may cause pressure buildup in various levels of the annulus. Current monitoring data covering pressure, temperature in injection/production wells, and annulus protection fluid level alone cannot accurately identify leakage points or specific leakage pathways in this gas storage.To enable precise remediation and effective control of annulus pressure buildup, fiberoptic monitoring methods based on DTS (Distributed Temperature Sensing) and DAS (Distributed Acoustic Sensing) technologies have been introduced.This paper introduces the principles of DTS and DAS fiberoptic monitoring technologies, along with their application in several typical wells. The results demonstrate that these technologies can effectively pinpoint leakage locations, providing support for targeted remediation of annulus pressure buildup. This approach also serves as a valuable reference for the treatment of annulus pressure buildup wells in other gas storage facilities.