This paper compared and analyzed the regulations for strain-hardening austenitic stainless steel studs in the domestic standards and the ASME Codes. When the domestic standards cannot meet the actual design requirements, the material type, nominal diameter and applicable temperature of strain-hardening stainless steel studs can be expanded. Since GB/T 150.1—2011 does not specify the allowable stress value of strain-hardening austenitic stainless steel studs, this paper provided a method to solve the problem and recommended the allowable stress value according to the metallographic and mechanical characteristics. The tension tests of austenitic stainless steel studs at room temperature and high temperature verified the effects of strain-hardening and provided reference for extending the application of austenitic stainless steel studs in domestic standard.

Aiming at the problem of solid-liquid separation of quench oil and coke particles in a million ton ethylene plant, simulation software was used to optimize the design of large-scale quench oil hydrocyclone with the diameter of 2 meters and the internal flow field and performance of the cyclone were also analyzed by numerical simulation. The large-scale hydrocyclone with the above optimized design has been applied in a million-ton ethylene plant successfully. Combining with the actual application, this paper carried out a study on the characteristics of the equipment under variable operating conditions, and compared the actual operating parameters with the numerical simulation results under the designed operating conditions. The results show that the actual operating parameters were consistent with the numerical simulation results, which indicates that the design method is of great practical value for engineering.

Selection of design pressures for high pressure equipment is critical to the safe production of hydrogenation units. If the design pressure is too low, the compressor shutdown will cause a high probability of safety valve take-off, and the operating pressure of individual equipment may exceed the design pressure, resulting in lower safety factor of the system; if the design pressure is too high, the corresponding investment will be increased. This paper presents a method for calculating the stagnation pressure of recycle hydrogen loop and determining the design pressure of cold high pressure separator based on the API 521 (6th edition) standard. By organizing and analyzing the on-site measured data collected during two interlock shutdown accidents of the recycle hydrogen compressor in a certain residue oil hydrogenation unit and comparing them with the results obtained by using this method, it is found that the calculated results from this method are highly consistent with the operational data collected from the actual production, and the stagnant pressure of the recycle hydrogen return circuit can be determined relatively accurately. The method provides guidance on how to determine the design pressure for new and revamped hydrogenation units.

In order to diagnose the deviation of interstage pressure of reciprocating compressor, this paper selected a representative example and carried out coupling analysis of the effects of process parameters, leakage faults and flow regulation on the interstage pressure of reciprocating compressors through theoretical calculation. It explored the variation law of interstage pressure of reciprocating compressor under the simultaneous action of various factors. The analysis results indicate that the results and rules caused by various factors of different degrees acting on different cylinders are relatively complex, there may be greater deviation of interstage pressures due to synclastic superposition effect or interstage pressures being more consistent with the normal value resulting from reverse superposition effect. The study can provide certain theoretical basis for the analysis of interstage pressure variation of reciprocating compressor.

This paper introduces the material selection and preparation process of melt pump bearing bush of the extrusion granulator and conducts a comprehensive analysis and testing of the homemade bearing bush. 0Cr13Ni4Mo was selected as the matrix for the melt pump bearing bush of the extrusion granulator, and Stellite 6B alloy was clad on the inner wall and end face of the bearing bush by laser melting. Comparative analysis and test results show that the performance and parameters (e.g. composition, hardness, metallurgical organization, physical analysis of the coating, macroscopic profile, etc.) of the homemade bearing bush is close to that of the imported one, which indicates that the product preparation technology has made a breakthrough, and the imported bearing bush can be completely replaced by homemade one. This has filled the gap domestically in this field.

Hazard, danger, harm, risk, etc. are the basic concepts of risk management in safety engineering, and the current understanding of these concepts in the academic and engineering communities is still under debate and development. Ordinary technicians in the relevant industries generally still have a vague understanding of the connotation and scope of various concepts, and it is difficult to clearly distinguish the relationship and differences between them. There are often improper use or even misuse in actual engineering. Based on review of relevant literature and research on the actual situation of the industry, this paper conducted an in-depth analysis on the definitions of 10 basic concepts such as hazard, danger and harm and further clarified the connotation and scope of each concept. The association model between the concepts of hazard, danger, harm and unsafe condition were established, and the logical relationship between the concepts was clarified. The general idea of the classification of hazard, danger, harm and hazardous elements were clarified, and the corresponding basic classification methods were put forward. This paper plays a guiding role in standardizing the use of basic concepts related to risk as well as specific tasks such as hazard identification.

The production operation cycle of the gas-desalted water heat exchanger in a hydrogen production unit is required to be 4 years, but leakage occurred before the actual tube bundle had been operated for 4 years. This resulted in an unplanned shutdown of the unit and affected the long, safe, and stable operation of the related hydrogenation unit, and also caused a certain amount of economic loss. Shortly after the standby tube bundle replaced the leaky tube bundle and was restored to service, the standby bundle leaked again. In order to solve the above leakage problem and eliminate the hidden dangers, the leaky tube bundle was tested and analyzed, and the equipment and operation of similar hydrogen units were investigated. Finally, a modification plan was formulated in which the material of the tube bundle was kept unchanged, and only the structure and manufacture of the tube bundle were optimized and improved, together with the improvement of the process operation and control. The reformed tube bundle has been in good condition after being put into operation, and the problem of tube bundle leakage has been solved. The above modification plan can provide reference for similar devices and equipment with similar problems in engineering practice.

During the operation of the lining equipment and pipeline of the existing MTO plant, failures such as hot spots on the equipment wall, shedding of the lining, wear-out of the equipment wall and leakage of the catalyst occur from time to time, so it is very difficult to monitor and handle the temperature. Based on the analysis of the distribution of the bed layer and the operation of the medium in the equipment and pipeline, it was found that the different concentration and particle size of the catalyst in the bed layer of the anti-regenerator system have different wear on lining and the internals. Based on the bed structure, the inner parts and the lining structure were optimized. The inner parts using the inner and outer double lining structure can effectively reduce the wear of the inner parts. Meanwhile, by comparing the different temperature rise and temperature reduction time during start-up and shut-down, another main factor of lining damage was found out, which has positive effect on preventing lining damage and failure and prolonging its service life.

Safe and efficient purging of residual fluid in coiled tubing can effectively reduce the load of the vehicle-borne roller after the completion of a coiled tubing operation and reduce the risks during long-distance transportation. Meanwhile, the risks of blocking and holding pressure caused by freezing of residual fluid in coiled tubing operation in winter can be avoided, which provides a reliable guarantee for the follow-up complex analysis of the coiled tubing in downhole operation. In order to realize the effective purging and the intrinsic safety of the equipment, a residual liquid purging device for coiled tubing was developed based on the design scheme of the linkage operation process between the diesel high pressure compressor and the gas storage tank. Through indoor and field tests, the performance parameters of the device, such as pressure at all levels, rotating speed, maximum working displacement, rated gas storage pressure, rated gas storage capacity and effective purging time, were verified and the performance and purging efficiency of the device were analyzed and evaluated. The development of the device provides a feasible method for the safe and efficient purging of the residual liquid in coiled tubing.

Nickel-based alloys are commonly used as welding materials for 9%Ni steel LNG storage tanks. Due to the particularity of the materials, radiographic inspection methods are often adopted for non-destructive detection of welded joints. The base material and weld metal have different radiation absorption properties, thus single-film transillumination cannot meet the blackness requirements of the base material and the weld metal at the same time. This paper presented comparative tests that were conducted respectively with single-film, double-film and digital radiography technology in radiographic inspection methods. It also analyzed the test results and developed the inspection process that can meet the testing requirements of nickel-based alloy base metal and weld metal.

In a refining and chemical company in central China, the pressure drop in the vacuum tower of an 8.0 M/a atmospheric and vacuum distillation unit increased significantly in the middle and late stages of the second operation cycle after commissioning, which seriously affected the smooth operation of the unit and the total distillate yield. Through analysis, this was mainly caused by the coking in the washing section of the vacuum tower which resulted in the reduction of the gas-phase channel and the rise of the pressure drop, thereby leading to the reduction of the flash volume in the feed section and the decrease of the distillate yield of the vacuum tower. During the major overhaul in 2017, the bed height of the packing was modified and the corrosion and coking resistant surface treatment were carried out on the packing of the washing section. The pressure drop in the vacuum tower and the distillate yield of the unit were stable for 1 cycle after the modification. And coking of the packing was found to be significantly improved in the overhaul in 2021. The transformation results show that the application of surface modification technology, in combination with the adjustment of operation, can effectively slow down the coking trend of the packing surface in the washing section, avoid the reduction of the distillate yield due to the increase of the pressure drop of the vacuum tower, and achieve remarkable economic benefits.

With the increasingly severe environmental protection situation, the full-connection liquid floating deck which can prevent oil volatilization is widely used in the internal floating roof storage tank. Among such decks, the pontoon floating deck is relatively good. However, during the long-term use of the pontoon floating deck, the medium of the floating tank may infiltrate into the pontoon due to corrosion or stress. Since the infiltrated medium is combustible, this poses a major safety hazard to tank maintenance. This paper mainly introduces the application of the new pontoon breaker in the process of breaking and dismantling of pontoon floating deck. Through the comparison with the traditional treatment methods, it is concluded that the pontoon breaker is the best and safest treatment method for the pontoon floating deck in China. The application of such breaker solves the problem of difficult treatment after the medium is introduced into the pontoon floating deck.

The rotating machinery fault on site is complex. Due to the non-stationary signal, the diversity of fault causes, the uncertainty between fault symptoms and faults, the mixing of faults and other reasons, the relationship between faults and symptoms is not completely one-to-one. When conducting equipment vibration analysis and diagnosis, it is necessary to fully grasp various equipment information and flexibly use vibration principles and measurement skills. The organic integration of experience and professional knowledge can effectively carry out fault diagnosis and treatment. Taking a relatively serious failure of a core unit as an example, this paper describes in detail the analysis and handling process of the failure. Based on the application of vibration diagnosis theory, this fault analysis comprehensively uses various types of vibration analysis atlas extracted by the S8000 large rotating machinery vibration monitoring system. Such analysis method can provide reference for the fault diagnosis, analysis and treatment of rotating machinery similar to high-speed flexible turbine rotating machinery.