Large tubular reactor is key equipment in petrochemical plants. The structure of such reactor is similar to the fixed tube sheet heat exchanger in which the cylindrical shell on channel and shell side are welded with the top and bottom fixed tube sheet. With the scale of plants increased, the number of heat exchange tubes in such reactor is increased, resulting in large number of tubes. The 3D model is established for finite element stress analysis, which is inconvenient to use. In the analysis and calculation section of Annex in the ASME VIII.2 standard, the perforated plate design method based on the elastic stress analysis in Appendix 5-E is adopted to change the tube plate into an equivalent solid plate for stress analysis, which simplifies the calculation and is currently a more general approach in the world. This paper details the method of stress analysis of a large tubular reactor using the equivalent solid plate in ASME VIII.2, and compares it with the actual 3D model calculation. The results show that this method is reliable and can be applied in practical engineering.

This paper introduces the function, structure and technical characteristics of lock-hopper which is the core device of large coal chemical equipment. Through manufacturing specifications, technical requirements and various process evaluations, reasonable and standardized technical parameters for molding and welding are determined. The paper also describes key technologies in detail including material control, welding method selection, transition layer surfacing, cover coat surfacing and heat treatment. The manufacturing process is controlled strictly and the welding quality of the equipment is guaranteed so as to complete the equipment manufacturing task successfully.

Based on the basic principles of heat transfer, this paper carries out mathematical modeling and computational analysis on the temperature at the end of the suction valve pipeline at the top of a cryogenic ethylene storage tank in northern China in winter. By combining with the local atmospheric conditions, this paper analyzes whether the suction valve pipeline will freeze in extreme conditions, which may affect the reliability of suction valve. The calculation results indicate that even the heat input factors such as sunshine and heat conduction are fully ignored, the suction valve pipeline can still ensure that there will be no icing, and the reliability of the suction valve can be guaranteed with the designed appropriate extended length.

Vertical shell-and-tube, shell-and-plate and double shell U-tube are three typical types of heat transfer in the second stage of pyrolysis gasoline hydrogenation unit. This paper introduces the structural characteristics, industrial application and operation effect of these three types of heat exchangers, and compares them in terms of equipment cost, heat transfer performance under long-term operation, pressure drop changing trend, energy consumption and their cleaning and maintainability. It is concluded that double-shell U-tube type is the best structural type, which provides a reliable basis for the type selection of feed-effluent heat exchanger for the second stage pyrolysis gasoline hydrogenation unit.

High-speed centrifugal pump is of small flow and high lift. It has stable specific performance coefficient, reliable and steady speed-up mechanism and sealing device, high anti-cavitation and corrosion resistance performance. The high-speed centrifugal pump can run continuously for 3 to 5 years. And whether the maintenance and overhaul work is in place or not is directly related to the service life of the pump and the continuous production time of the device. So the maintenance work of high-speed centrifugal pump is very important in a refining enterprise. Reliable maintenance and correct overhaul methods are the guarantee for the stable and long-cycle operation of high-speed centrifugal pump.

The washing tower feed pump was used for the gas water separation unit in the gasification device of a large coal chemical project and operated stably for nearly one year. A serious production accident of shutdown occurred because of broken shaft when there were no abnormalities appeared in the central control room and on-site inspection records. Entrusted by the owner, our company has carried out disassembly, cleaning, testing and maintenance of this pump. After replacing the pump shaft, mouth ring, shaft sleeve, bushing and other friction pair during this emergency repair, the pump has operated smoothly so far without similar accidents. Since the causes of the accident were unknown, this paper analyzes and troubleshoots the causes from such aspects as rotor strength, material selection, and structural design. It finally found the causes for the accident accepted by both sides. Meanwhile, the paper summarizes the key considerations for the safe and stable operation of the pump.

This paper introduces the shutdown accident caused by the imbalance of steam/carbon ratio in the unit resulting from the sudden rise of rotational speed, initial steam flow rate and steam extracting amount and then a large drop because the speed governing system in the steam turbine of syngas compressor was out of control. According to the governing mechanism, control components structure and working principles of steam turbine and combining with the characteristics of the accident, the paper analyzes the causes of the accident. It excluded the impacts of steam turbine high pressure steam pressure, exhaust steam pressure, extraction control valve and compressor load on the accident and confirmed that the main stop valve opening was out of control, which was the main cause of the accident. Through further analysis, the paper excluded the impact of oil particles in the pilot valve on the main steam valve. Based on the analysis results and through on-site static debugging, it is found out that the feedback lever and the feedback transmission rod connecting bolt were disengaged. After fastening the connecting bolt and carrying out static test on the control mechanism of the main stop valve, the fault was eliminated. In order to prevent similar faults from happening again in the steam turbine, corresponding requirements have been made in management.

Longitudinal cracks were found in the drum of 410 t/h circulating fluidized bed boiler (CFB boiler) in a petrochemical self-owned power plant after 7 years of operation. Through studying the hardness and operation conditions near the cracks, the causes of cracks were analyzed in depth and the repair methods of welding cracks were put forward, which could provide reference for the timely repair and proper treatment of similar drum defects.

After the overhaul of the steam turbine unit in a petrochemical company, a joint test was carried out. During the test, when the rotating speed of the unit was increased to 10700 r/min, the vibration value of the vibration measuring point VE3349A of the steam turbine coupling side shaft was 39μm; the vibration value of VE3244 of the driving side shaft of the low pressure cylinder was 43μm; and the vibration value of the two shafts was higher than the value before the overhaul. According to the analysis of vibration waveform spectrum, axis trajectory and Bode diagram, dynamic balance was adjusted on site and the effect was obvious. The shaft vibration was reduced greatly and the hidden troubles were eliminated.

Heating furnace is important equipment in oilfield gathering and transportation system. Its function is to heat the mixture of oil, gas and water to the temperature required by the process to meet the requirements of oil and gas gathering and transportation and processing technology. Aiming at the shortcomings of low thermal efficiency, high energy consumption and low level of automatic monitoring of oilfield heating furnace, a new type of vacuum phase change heating furnace is developed, which has the functions of automatic adjustment of combustion load, automatic purging, automatic ignition, continuous flame monitoring, flame extinguishing protection and gas solenoid valve leak detection to improve the level of safety protection. The low temperature phase change heat transfer technology is applied to improve the heat transfer efficiency of heating furnace; the closed-loop combustion system of flue gas oxygen is used to control excess air coefficient and other measures are adopted to improve the system operation efficiency. The closed automatic conveying device for fuel gas purification; is developed to realize the automatic separation and closed conveying of gas and liquid. Meanwhile, remote transmission and automatic monitoring of pressure, temperature and other operating parameters as well as their informatization and digitization are realized, which meets the needs of on-site production of oil fields.

In order to meet the requirements of new environmental protection laws and regulations, revamp of low nitrogen burners is carried out for all the heating furnaces that fail to meet the discharge standards. Aiming at the heating furnaces that operate continuously and can’t be shut down in a short period of time, a revamp method of online non-stop furnace low nitrogen burner is studied. In the case that the original brazier and refractory brick can't be changed, the old round air staging burner is transformed into fuel staged burner to reach the goal of low pollution emissions.

The total module weight of a single 200 KTA ethylene cracking furnace in certain domestic petrochemical enterprise weighs 3689.6 tons, and its size (length × width × height) is 41.1 m × 20.9 m × 53 m, which has been installed at the project site. The cracking furnace module is the first complete modularized design and construction for cracking furnace in China with SPMT roll-on, sea-solid, sea/land transport, SPMT in place. It’s also the world's largest single cracking furnace module installed through complete modularized construction and transportation. The successful implementation of this project has changed the traditional on-site construction mode of cracking furnace.

There is plenty of dissimilar steel welding and overlay welding in hydrogenation reaction system. Dissimilar steel welding has the defects of unbalanced material properties and uneven thermal expansion. Interfacial stress, interface H concentration and carbon migration during surfacing are the key factors leading to hydrogen-induced disbanding of the hydrogenation equipment surfacing layer. The overlay welding method will affect the interface metallographic structure and the tendency of hydrogen-induced disbanding. Such issues as how to understand the characteristics of dissimilar steel welding correctly, how to select welding materials accurately and how to select more reasonable use of welding methods are worthy of discussion. Experiences have shown that for hydrogenation equipment, it is reasonable and feasible to adopt submerged arc overlay welding for single-layer overlay welding and adopt automatic submerged arc overlay welding plus automatic electro slag overlay welding for two-layer overlay welding.

With the development of petrochemical production, chemical plants have become larger and been in large scale. And the key equipment has played a crucial role in their safety, reliability and efficiency during the process of production and operation. Taking the "three machines (cracking gas compressor, propylene compressor, and ethylene compressor)" in ethylene plant as an example, this paper analyzes from the aspects of equipment design, manufacturing, construction and operation management, and expounds how to improve the reliability of key units. This provides certain technical reference for the design, manufacture and use of large equipment in chemical industry.