Buried tanks usually need multiple openings in the manhole cover on the top of the tanks in order to meet the needs of process pipe connection, which places higher requirements on the calculation of the opening reinforcement of the flat cover and the arrangement of nozzles. Currently, there are certain problems in the design of multiple openings for flat cover by adopting GB/T 150.3—2011. Based on the finite element method, this paper establishes a complete model of bolted connection flat cover, studies the strength and sealing of the structure under different parameters, and discusses the design of openings and the arrangement scheme of nozzles. The results can provide reference for the relevant design.

The performance parameters of seawater desalination device under different regenerator setting modes were simulated and compared by using Aspen Plus software in this paper. The setting positions, setting number and air extraction positions of regenerators were analyzed systematically, thus the setting method of regenerator was proposed. The results show that the water production rate can be significantly improved by adding regenerators; the fresh water production rate of the unit is higher when the regenerator is installed in the main pipe than in the branch pipe and small main pipe. Increasing the number of regenerators in the seawater desalination device can improve the water production rate. The research results are of guidance for practical engineering applications.

The seismic design guidelines or methods for the U.S. pressure vessel design standard ASME Ⅷ-1&2 (2019 edition) and the storage tank design standard API 650 (2019 edition) are derived from U.S. ASCE 7-10 (2010 edition) Minimum Design Loads for Buildings and Other Structures. This paper analyzes the seismic design method of petrochemical static equipment based on ASCE 7-10 (2010 edition) in terms of seismic level and target, risk category and seismic importance factor, seismic design response spectrum, seismic action calculation, seismic calculation of frame-supported equipment, load combination and seismic verification guidelines, and other seismic design requirements. It summarizes the characteristics of the seismic design methods, with the aim of providing reference for the implementation of foreign projects and the boost of the development of seismic design technology for petrochemical static equipment in China.

In order to obtain the temperature change rules of the composite CNG cylinder during inflation, the inflation process of the cylinder under 30 MPa was numerically simulated by Fluent 17.0. And the temperature distribution and change rules of the internal gas during the inflation process and the wall temperature rise were obtained through analysis. The simulation results were analyzed for the gas cylinder with heat conducting medium added to the outer wall under the same conditions. The results show that the high temperature area of the gas cylinder is distributed in the head section of the bottle tail; the low temperature area is distributed in the inlet position; and the temperature distribution at the inlet presents a plume shape. The gas temperature continues to rise, but it has a nonlinear relationship with time. The highest temperature rise rate of the fiber layer of the gas cylinder has been significantly increased, while the average temperature rise rate of the cylinder has a small increase, but the temperature rise rate of the inner bladder layer slightly decreases as the filling progresses. The temperature rise of the wall has not been linearly related to the inflation time. The thermal conductive paste keeps the temperature rise of the cylinder wall stable, and its temperature is reduced at the end of inflation.

Elephant foot buckling (axial compressive instability) of the lower part of tank wall, collision between floating roof and fixed roof, and overturning of storage tank as a whole are the common damage of large storage tank under earthquake load. For this reason, corresponding provisions were made in the U.S. and Chinese design codes for seismic design of large storage tanks. Combining with engineering cases, this paper focuses on comparing the differences between the anchorage coefficient, the maximum axial compressive stress of the bottom ring tank wall and the sloshing wave height in the seismic design calculation of the U.S. and Chinese design codes. The results show that for the calculation of anchorage coefficient, the domestic code took reference from the calculation formula of the American code, but didn’t take into account the impacts of the site category and the importance factor of the storage tank on the anchorage coefficient; for the calculation of axial compressive stress in the bottom ring wall, the domestic code expressions were similar to those in the American code in the case of anchorage or when the anchorage coefficient was not more than 0.785; the calculation results were mainly affected by the vertical seismic acceleration and coefficient of moment adjustment, while in other nonanchored cases, the difference between the two calculations was also affected by the different values of the buckling coefficient; for the calculation of sloshing wave height, the domestic code took the influence of tank shape into account, while the U.S. code took the influence of seismic use groups, the basic cycle of liquid storage sloshing, and the acceleration of the reaction spectrum into consideration.

In recent years, as the scale of ethylene plants continues to expand, the compressor units used are becoming larger and larger. Meanwhile, higher requirements are also put forward on the operational stability, reliability and safety of compressor sets. Based on the engineering practice of a large ethylene plant, this paper introduces the research and development process of localization of the first 100 MW extraction-condensing pumping turbine for cracked gas compressor in China. It expounds the main parameters, structural configuration and technical features of the turbine, in which a number of technological development and application innovation have solved some key problems in ethylene plants at home and abroad. The localization of this turbine not only saves investment and maintenance cost, reduces the project design and installation cycle, but also provides solid technical guarantee for the design and construction of larger-scale ethylene plants in the future.

In the production preparation stage of 800 kt/a ethylene plant, high temperature of bearing bush of low pressure cylinder occurred during the commissioning of cracking gas compressor. This phenomenon may be caused by abnormal friction, or by poor heat removal capacity due to insufficient oil. High temperature of bearing bush will cause the lubricating oil to carbonize and accumulate carbon on the bearing surface, further accelerating wear of the bearing bush, which is not conducive to the long-term operation of the compressor. The cracking gas compressor is the key equipment of the ethylene plant, and its operation determines the operation cycle of the entire plant. In order to ensure the long-term operation, it is necessary to analyze the problem comprehensively and take effective and reliable measures to reduce the bearing bush temperature.

Aiming at the frequent occurrence of local material fracture, perforation and thinning in the inlet and outlet pipes of convertor and process syngas waste heat boilers at home and abroad in recent 15 years, this paper analyzes the stress release cracks in the collecting main, high-temperature hydrogen corrosion in the outlet cold-wall collecting main and CO metal dusting in the process syngas waste heat boiler respectively. And it elaborates on the material failure mechanism, engineering application and prevention measures. It is considered after the analysis that reasonable material selection, welding, heat treatment and non-destructive testing can prevent or mitigate the above-mentioned material failure to a certain extent.

The failure of stress corrosion cracking of light-component removal column was analyzed by means of metallographic, SEM, and chemical composition analysis. It was concluded that the failure was caused by stress corrosion cracking of austenitic stainless steel in polythionic acid environment. The electrochemical and SCC test of selected stainless steel of 321, 316L and 2205 were carried out. The results showed that 316L and 2205 steels have good SCC resistance to polythionic acid. The above conclusions can provide a basis for the selection of materials for the system.

In order to explore the corrosion resistance of stainless steel S30403 in circulating water and guide the selection of materials, this paper adopts slow strain rate tensile test, cyclic dynamic potential polarization and other methods to study the stress corrosion and pitting resistance of the material in circulating water with different chloride ion concentration and temperature. The results show that: when the medium temperature is 60 ℃ and below and the chloride ion concentration does not exceed 10 000 mg/L in circulating water, there’s no stress corrosion cracking sensitivity in S30403, which can meet the stress corrosion cracking resistance in the circulating water of water cooler; when the chloride ion concentration is higher than 250 mg/L and the temperature is 40~60 ℃ in the circulating water, there’s pitting corrosion sensitivity in S30403; under such condition, the S30403 will be at risk of pitting corrosion in long-term service.

Aiming at the problems of suspension of the adsorbent circulation, disqualification of product, flameout of catalyst regeneration, and removal of fresh raw material, non-disassembly cleaning device was designed and manufactured through studying the selection of impeller type, impeller size and speed, stirring power, stirring bearings, seals, filter elements and their pore sizes according to the internal conditions of the filter at the bottom of the regenerator. This device achieved 100% success rate of on-site application. When the filter is blocked after installation and use of the device, the adsorbent block can be broken by shaking the device. This can lower labor intensity, reduce safety and environmental risks in the processing process, ensure product quality and realize stable production of S Zorb device, saving 80,000 yuan of annual cost.

The operation condition of the rich gas compressor in delayed coking unit is directly related to the smooth operation of the whole unit, and the steam turbine is the most important part of the driving unit. This paper analyzed some problems of rich gas compressor in delayed coking unit during the operation period. Combining with the operation parameters, it analyzed the causes of the failure according to the disassembly and inspection situation. Meanwhile, the paper summarized the problems encountered in the start-up process of the unit after maintenance in July 2020 and the situation in operation. It focused on analyzing the phenomenon of the speed control system in the start-up stage of the unit and several large fluctuations of the steam turbine inlet volume in operation. In addition, it also analyzed the problems encountered in the process of starting-up after the overall replacement of the speed control system. After this troubleshooting, it was concluded that the bolt fracture of the governing valve was the direct cause of the decline of the turbine's power capacity, and the indirect cause of the failure was that the pressure bearing parts were not replaced after two consecutive long-term operation. Each overhaul of a large oil refining unit determines whether or not the whole unit could run for a long period of time, so the depth and accuracy of each overhaul of a large unit plays a crucial role.