In recent years, the method of modular design for furnaces has been widely adopted. With the rapid development of our country's proprietary aromatics technology, the new large-scale xylene tower reboiler for aromatics planthas also been developed and applied. The new furnace type features a modular design that allows for the combination of multiple radiation cells, providing a technical foundation for series design. By continuously optimizing the modular design concept and structure during the design process, the specifications of the modules can be reduced. This not only facilitates mass production by manufacturers, but also improves the efficiency and quality of on-site installation. This paper explores the series standardization and modular design of the reboiler radiation section in xylene tower so as to provide reference for the designers to design similar devices.

Reforming reactor is the key equipment of continuous reforming unit. In the reactor, the contact between the gas and solid phases is a cross flow contact. The abnormal phenomena cavity and pinning could occur if the gas flow is large enough, which may greatly restrict the operating flexibility and affect the safe and stable operation of the reactor. Acoustic emission technology was used to detect the reactor under cold operation. The acoustic emission data of different operation states of the reactor were compared and analyzedso as to determine in time whether the above-mentioned abnormal phenomena occurred or not.The experimental results showed that the waveform was stable during normal operation of the reactor and the average signal level was 20 dB; the amplitude was 35~45 dB. The waveform displayed pulse shape when the reactor was abnormal. When cavity appeared, the average signal level was 20~35 dB; the amplitude was 35~55 dB and the characteristic frequency was 25~150 kHz. When pinning appeared, the average signal level was 30~60 dB; the amplitude was 35~75 dB and the characteristic frequency was 25~250 kHz. The waveform, characteristic parameters and power spectrum of the signal changed obviously when the flow state of the catalyst changed. By using multiple sensors, the fault could be located and the fault type could be identified. The above results indicate that as a non-invasive measurement technology, acoustic emission technology can effectively detect the operation state of the continuous reforming reactor and can provide technical support for the long-term safe and stable operation of the device.

During maintenance, it was found that the output shaft of reducercracked and the inner hole of the output gear was worn. The analysis indicated that the fatigue resistance of the output shaft of reducer material was insufficient, which induced the cracking of the output shaft of reducer. The expeller operated under medium and low loads for a long time when producing dry rubber. Meanwhile, the design layout of the screw was unreasonable and the clearance between the screw and the barrels was small, which caused scraping and grinding of the screw and the barrels, thus triggering the abnormal noise and vibration. The fatigue cracking of the output shaft of reducerwas accelerated under the combined action of alternating loads, abnormal vibration and accumulation of lubricating oil elements. The clearance fit between the output shaft of reducer and the output gear intensified the micro motion between them due to the cracking of the output shaft of reducer,which eventually led to the wear of the inner hole of the output gear. In view of the fact that the wear of the output gear inner hole was within controllable limits, the treatment plan was adopted to repair the inner hole and the surface of the output gear. And the cracked output shaft of reducer needed to be replaced by a new one. The new domestically produced output shaft of reducer adopted 34CrNi3Mo with better mechanical performance and the heat treatment process was optimized. And then, it was paired with the repaired output gear inner hole. In addition, the layout of the screw has been optimized; the outer diameter of the screw has been appropriately reduced and the operating load of the unit has been increased in order to make the operation of the dewatering extruder safer and more stable.

Tapered keyless coupling hubs are designed for interference assembly, which is generally applicable to large rotating equipment with high speed and high transmission torque. The main function of interference fit is to prevent the occurrence of axial or radial movement of the coupling at the shaft head through friction, ensuring smooth operation of the machinery. After operation of the unit, the friction between its keyless coupling hub and the shaft head will increase, which will result in the increased difficulty of hub disassembly and installation. If there is a failure during hub disassemblyand installation, it will directly affect the smooth operation of the whole unit or even the device.This disassembly and installation technology is generally mastered only by the manufacturer's field service personnel. If there is a need to disassemble and install the hub, it is difficult for on-site inspection and maintenance personnel to solve the problem.This paper introduces the process points and difficulties of disassembling and installing the coupling hub of a typical BB5 high-pressure centrifugal pump in the overhaul process, and specifically describes the technical points and precautions for disassembling and installing the keyless coupling hub by using the hand-held high-pressure oil pumps and low-pressure oil pumps and combining with the on-site practice, which can provide reference and useful experience for the inspection and maintenance of the same type of tapered keyless coupling hubs.

Corrosion problems are still prevalent in refining units, even in very mature conventional units such as catalytic cracking units after decades of development. The main problem is the lack of comprehensive and systematic methods to solve corrosion problems. Through summarizing a large number of standard specifications, corrosion mechanisms, engineering design experience, and analyzing the corrosion problems of hundreds of device on sites, this paper found that two levels of solutions to device corrosion problems were required:1) from the spatial dimension, integrating professional corrosion prevention work such as engineering design and application processes and equipment to form an overall corrosion prevention work method for the device; 2) from the time dimension, the experience and lessons accumulated and drawn from the industry are structured and systematically integrated to provide technical support and services for engineers and technicians to improve their ability to analyze and solve corrosion problemsquickly.

Ethylene oxide (EO) is an important raw material for organic synthesis, which is second only to polyethylene and polyvinyl chloride. It is mainly used to produce ethylene glycol (EG), which is the main raw material for producing polyester products and antifreeze. EO/EG is usually co-produced and is an important downstream derivative of ethylene industry. The stable operation of its production equipment is of great significance to the ethylene balance of the whole refinery. The operation experience indicates that EO/EG plants have systematic and universal corrosion problem. In order to solve the corrosion problem, the EO/EG plants were systematically investigated from the aspects of production operation, catalyst use, structural adjustment, failure cases of on-site corrosion, corrosion management, RBI risk analysis, corrosion monitoring and detection, etc., to find out the impact of various factors on the corrosion of EO/EG plants and the production management experience of enterprises, and to provide technical support for the future research on the overall solution to corrosion control of EO/EG plants.

Carbon steel amine heat exchangers are often used in the design of most domestic natural gas purification plants, yet corrosion damage is often encountered in actual operation. Therefore, more and more enterprises begin to adopt stainless steel tube bundle heat exchangers. The pitting corrosion and stress corrosion cracking (SCC) susceptibility of 304L stainless steel in alkaline environment with high sulfur and chloramine content were studied through experiments. The applicability and safety of the material are verified under the operating conditions of the heat exchanger with lean amine solution. This provides an effective basis for the rational control of the use-cost of heat exchange equipment materials in high sulfursour gasfields.

The Close interval potential survey (CIPS) has a good detection effect on the cathodic protection potential distribution and cathodic protection situation of petroleum and natural gas steel transmission pipelines. However, due to the poor contact between the CIPS probe and the soil and the influence of stray currents, there is significant interference on the on/off potential in CIPS detection in dry sandy areas and areas with severe stray currents. It is difficult to determine the true protection potential through directly collected data signals. The threshold wavelet denoising method based on the Birge-Massart strategy can effectively suppress the noise signal caused by poor contact between the probe and the soil, while making it easier to identify the affected area of stray currents.

As an important safety device, safety valves are widely applied in various industrial fields. They play a key role in ensuring the safety of equipment and people. This paper presents in detail the application of safety valves in chemical industry, and discusses the methods to correctly calculate and select safety valves under the requirements of specific working conditions and media characteristics. Through an in-depth analysis of the type, operating principle, calculation method and selection criteria of safety valves, practical recommendations are provided to ensure the safe operation of the plants. This paper also discusses the calculation of safety valves in two-phase flow fluid. By comparing the venting areas of the gas-liquid phase from separate calculation and calculationby the omega method, a relatively reliable basis for selection is derived, which can provide reference for the design of safety valves in similar process devices in the future.

The packing seal is an important part of the new hydrogen compressor, and its working reliability determines the operating cycle of the compressor. Based on the three consecutive leakage failures of the three-stage packing seal in the new hydrogen compressor, this paper analyzes the causes of the packing seal leakage from the structure, arrangement form and disintegration inspection results of the packing seal. It proposes such measures as changing the packing ring material, combination form, and increasing the oil injection amount for improvement. After 4 months of operation practice, the results indicate that the effect of the revamped packing sealing is good and the service life is extended. The successful revamp of this case provides valuable experience for the repair of packing seals in new hydrogen compressors.

This paper focuses on the frequent leakage of the mechanical seal of the bottom pump in the atmospheric and vacuum distillation unit of a certain refinery, which led to multiple operational fluctuations of the unit and affected the normal production order of the refineryseriously. Each seal leakage causes direct economic loss of nearly 100,000 yuan and a large amount of residue oil needs to be cooled and emptied for seal replacement. This not only wastes precious resources, but also increases processing costs and environmental pollution risks. To solve the problems, this paper analyzes in depth various reasons affecting the mechanical seal effect. Through elaborate optimization design of the sealing structure and precise adjustment of the sealing auxiliary system, the expected effects were achieved after the new scheme was put into use. This has improved the operational stability and economical efficiency of the unitsignificantly.

This paper analyzes the problems existing in the cracking gas compressor GB-201 of an ethylene plant covering the operation difficulty, low compressor efficiency and high energy consumption. It is found through the analysis that there are hidden equipment dangers in the unit including long service time, poor sealing performance and aging of the oil ring in the compressor body, internal gas blowby and three section outlet overpressure and so forth. Therefore, the compressor unit and its auxiliary equipment were updated as a whole by adopting a high-efficiency turbine driver with high pumping capacity and a high-efficiency ternary impeller compressor.After the revamp, the compressor efficiency was improved significantly under the same working condition, and the energy consumption of the device was improved effectively. This provides valuable experience in solving such problems for cracked gas compressors in ethylene plants.

The phenomenon of amplitude fluctuation at 1X frequency appeared after overhaul of the syngas compressor turbine. Through analyzing and troubleshooting the causes, it was finally confirmed that the damage of a carbon brush on the exhaust side of the turbine during overhaul was the root cause of the problem of amplitude fluctuation at 1X frequency. Aiming at the causes of the fluctuation, reasonable measures were taken to successfully solve the problem of amplitude fluctuation at 1X frequency of the steam turbine. This case can provide reference for the overhaul of the steam turbine of syngas compressor units with similar problem.

Equipment in the petrochemical industry is usually operated under high temperature and high pressure conditions, and most of its media are flammable, explosive, toxic and corrosive, etc., and it is prone to malfunctions or accidents during operation, which may result in serious hazards.Although the failure rate can be reduced to a certain extent by strengthening the equipment management during operation, it cannot guarantee the intrinsic safety of the equipment. Starting from the design selection, procurement, manufacture and installation of equipment during the construction period, this paper elaborates on the necessity and importance of strengthening equipment management and proposes specific measures. This can provide reference for improving equipment reliability and reducing the occurrence of equipment failures.