To prevent the occurrence of low temperature brittle fracture, impact test is generally adopted to check the material toughness, but the cost of impact test occupies a large percentage of manufacture cost of pressure vessel. ASME code gives detailed rules on the conditions under which impact test is mandatory or exempt. However, unclear understanding of concepts and misapplication of ASME code often happens to engineering designers in China. This paper thoroughly sums up the requirements of impact test for carbon steel and low-alloy steel materials and parts in the 2015 edition of ASME code, and provides a flow chart for judging whether a material or component can be exempt from impact test or not so as to help engineering designers to fully understand these specifications.

As the key equipment in natural gas liquefaction process, seawater-mixed refrigerant heat exchanger is mainly used for cooling/condensing the multistage compression medium (mixed refrigerant).Through plenty of investigations and experimental researches, this paper determines the heat exchanger with corrugated low finned tube/ double helical baffles structure as the preferred scheme of seawater-mixed refrigerant heat exchanger. Through quality control of raw materials, heat transfer elements, critical component and assembly process, the seawater-mixed refrigerant heat exchanger is manufactured successfully, which lays a good foundation for the development of the seawater-mixed refrigerant heat exchanger.

At present, AR technology is rarely used in petrochemical enterprises, and there are market vacancies. The development environment applied in this paper is Unity 3D, and with the secondary development of C# language and the aid of Solidworks modeling software, the application of AR technology in petrochemical industry and petrochemical education and teaching field is realized. This paper mainly introduces the application process of AR augmented reality technology, and gives an application example of AR technology in petrochemical enterprises and petrochemical education industry.

Through reasonable simplification of the spinning forming process of standard elliptical head, the trajectory of the spinning roller is determined by geometric method in the single-pass spinning forming process. On this basis, the three-dimensional finite element model of the standard elliptical head is formed by adopting ANSYS/LS-DYNA software. The model obtains the numerical analysis results that meet the actual requirements. According to the model results and elastoplastic finite element theory, the deformation mechanism of the blank during the spinning forming process is analyzed, and the distribution of stress, strain and thickness at different positions during the forming process is obtained. This provides an effective method and reliable basis for the study on the spinning forming process of head.

Gear fault is the main form of gear box fault. Therefore, the judgment and analysis of gear running state is of great significance to reduce the gear box failure rate and prevent sudden accidents. This paper mainly introduces the application of spectral analysis method in fault diagnosis of gearbox gears. It summarizes the spectrum characteristics of common gear faults. Combining with the application examples, the paper analyses and diagnoses the gearbox breakage faults. The results show that spectral analysis can accurately judge the gear fault location and the severity of the faults. It can help the maintenance personnel to adopt the best maintenance strategy in combination with the actual running state, and provide an effective way for gear fault diagnosis.

This paper mainly expounds the generation mechanism of vibrations in centrifugal compressor units. It makes a detailed analysis on the characteristics of common compressor vibrations such as rotor unbalance and misalignment produced by rotor design, manufacture or use, half-speed whirl and oil whip induced by high speed hydrodynamic bearings, labyrinth seal fluid-induced vibration, surge, and so forth. Besides, corresponding prevention and countermeasures are put forward from the aspects of compressor design, engineering design and compressor operation. This provides guidance for designers and operators.

This paper introduces the basic situation of using Tekla Structures software for whole furnace design modeling of cracking furnace and its application to digital factory. Using Tekla Structures software for the whole furnace modeling design of cracking furnace changes the traditional design method and improves the design quality and efficiency greatly. Combining with the application in digital factory, the model transfer between upstream and downstream departments can be carried out; the design interface can be reduced clearly and intuitively and the design efficiency among different disciplines can be improved, which is of great significance for the application of digital factories in the design of cracking furnaces.

Shift converter is one of the key equipment in synthetic ammonia plant. Safe operation of the converter is important to the whole device. This paper introduces the real-time monitoring of the converter without shutting down by applying acoustic emission technology which can provide important guarantee for the safe operation of the converter. There are few researches on the long-term real-time monitoring of this kind of equipment using acoustic emission technology in China. Through analysis on the acoustic emission monitoring for four months, it is found that this technology is highly effective in identifying the crack in the converter pipe and its surrounding area; and with the monitoring time increasing, the amplitude of the acoustic emission signal is gradually increasing.

Black image on the base material of HP Low C static casting pipe elements in ethylene cracking furnace of a petrochemical enterprise appeared in the process of radiographic testing (RT). Through verification of optical and electronic metallographic observation combining with radiographic testing and penetrant testing (PT) and other non-destructive testing methods, it is determined that the black image is non-defective image display due to intergranular diffraction caused by local coarse grain. This paper points out that non-defective image display from RT testing can be reduced or eliminated by changing the incident angle and energy of X-ray and adding the film hanger wave filtering.

After lubricating oil enters the dry gas seal of natural gas compressor, the oil film may absorb the heat from friction produced in the end face between rotating ring and stationary ring of the dry gas seal and result in damage of rotating ring and stationary ring due to their overheating. Therefore, it's necessary to figure out the reasons for oil entering. According to various possible factors that may cause oil entering and combing with the accident phenomenon, this paper analyses and investigates the reasons. It discovered that the root causes for the oil to enter the dry gas seal were that the lubricating oil pressure was too high and the effect of isolation gas became worse. A full adjustment was made for the header pressure of lubricating oil and oil pressure of thrust bearing and journal bearing of compressor. An attempt to purge the dry gas seal with oil instead of overhaul and replacing succeed. And corresponding countermeasures in management are put forward.

Aiming at the problems of frequent leakage and short service life of the mechanical seal in the power separator of polypropylene plant, this paper found that the high operating temperature of the sealing oil is the main reason for the short service life of the mechanical seal through analysis and calculation of the seal failure factors. The sealing oil circulation system was optimized by increasing the heat exchange area of the sealing oil heat exchanger and reducing the clearance of the screw sleeve of the pump. After one year of operation, the inlet sealing oil temperature of the sealing chamber of the power separator remained at 35 to 40 degrees and the leakage amount of sealing oil was basically stable at 0.3L per day. This optimization and transformation solved the problems of frequent leakage of mechanical seal of power separator, lengthened the service life of mechanical seal, reduced the number of shutdown times of the device, avoided the environmental pollution caused by plenty of seal oil leakage, and also created certain economic benefits for polypropylene plant.

By comparing several filter elements of different materials and structures, the filter elements of some equipment in polypropylene plant are upgraded. The non-metallic fiber PP felt which is easy to be blocked and ablated is upgraded to a strong and corrosion-resistant sintered metal fiber; and the disposable nylon filter element which is easy to be damaged is upgraded to a removable, cleanable and reusable metal filter. In order to separate oil and gas thoroughly, metal filter is used instead of wool in the oil and gas separator of the ice machine. After the revamp, not only the filtration and separation efficiency of the equipment is improved, but also the purchasing cost is saved greatly and long-term operation of the device is guaranteed.

To ensure the safe, stable and long-period operation of the steam turbine unit in chemical plant and bring more economic benefits to the factory, meticulous maintenance and operation of the process is needed. More importantly, reliability based maintenance shall be provided and maintenance time shall be shortened to achieve the goals of prolonging the shutdown maintenance intervals and ensure the long-period and stable operation of the unit when faults occur. Combining with troubleshooting and technical transformation of the turbine oil seal and instrument circuit, this paper reveals the importance of reliability based maintenance of the turbine.

The hydrogen sulfide stripper C-202 was added and put into use after the upgrading and revamp of certain diesel continuous liquid phase hydro-treating unit in October 2016. After being used, the stability of diesel quality was improved greatly. But in June 8, 2017, wall leakage was found at the seventeenth layer intake port of C-202 tower. This paper analyzes the causes for the wall leakage of C-202 tower in detail from such aspects as tower material, design operating conditions, actual operating conditions and corrosion. The causes for the wall leakage of C-202 tower are found out and the corresponding countermeasures are put forward

The new hydrogen compressor unit is the core equipment in the hydrogenation unit. It has many moving parts, which is prone to failure. This paper briefly introduces the basic situation of the new hydrogen compressor unit of the 1.60Mt/a diesel hydrotreating unit. Aiming at the current secondary load abnormal fault, motor bearing burnout, HydroCOM system failure and other problems occurred during the operation of the unit and combining with previous maintenance experience, the paper found out the causes of the failure and proposed some measures for improvement, which achieved good results. This provides valuable experience for long-cycle operation of reciprocating compressors of the same type.