Through theoretical analysis and numerical calculation, this paper analyzes the influencing factors, results and scope of the axial heat conduction on heat exchange tubes and shell cylinders. It obtained the formula for estimating the average axial temperature gradient of the cross section of heat exchange tubes and the formula for the effects of the axial heat conduction of heat exchange tubes and cylinder on the heat transfer of the main body. This provides a basis for rigorous heat transfer experimental research and engineering design.

Taking two different types of cyclones as the research object, the solid particles before and after separation were sampled and the particle diameter was analyzed in order to study the separation efficiency. The two cyclones were modeled separately and the incline angle of the cyclone inlet and the height of the vortex finder were changed, and the separation efficiency was calculated by numerical simulation. The simulation results show that the error between the simulation and experiment calculation results is within 15%, which verifies the accuracy of the results. The proper increase of the vortex finder height can improve the separation efficiency of cyclones. The pressure drop at the inlet and outlet increases first and then decreases with the increase of the height of vortex finder. The increase of incline angle of the inlet is beneficial to improve the separation efficiency of these two types of cyclones. After comprehensive consideration of the impacts on the inlet and outlet pressure drop of the cyclones, it is considered that the optimal s/a (the ratio of s \[the height of vortex finder of the cyclone\] to a \[the entrance height of the cyclone\]) of the compact cyclone is about 0.5 while that of the hot cyclone is about 0.75. The incline angle of the inlet of the compact cyclone should be about 10° while that of the hot cyclone should be about 15°. The above conclusions can be used to guide the structure optimization and transformation of cyclones.

Taking EO spherical tanks as example, this paper analyzes the difficulties and problems occurred when outlet nozzles are set at the top crown. It puts forward the preventive measures that can be taken when the inlet and outlet are set at the bottom crown of spherical tanks with extremely or highly toxic medium. According to the common problems appeared in projects and the successful experience of projects at home and abroad, the paper presents the idea that even if the spherical tanks contain highly or extremely toxic medium, it is feasible to set the inlet and outlet nozzles at the bottom crown of the spherical tanks as long as appropriate precautions are taken in designing. Meanwhile, it puts forward some suggestions on the revision of relevant standards and specifications.

With the increase in land costs, more and more investors tend to build steel full containment tanks without cofferdams and with small floor space and short construction period, but people in this industry have controversial understanding of full containment tanks. This paper starts to analyze steel full containment tanks from specification requirements, structural characteristics and other aspects. It gives an understanding of the definition of full containment tanks. Meanwhile, the paper raises the issues that should be noted when selecting tank types.

Large floating roof storage tanks have basically matured after decades of development. But up to now, there is still no standard for the setting principles and calculation method of PVV. In this paper, four kinds of positive and negative pressure working conditions of annular gas phase space are put forward by analyzing the structural characteristics and operation process of floating roof in detail. Through analyzing the damage risk of pressure components under each working condition, the paper arrived at the conclusion that PVV is an indispensable safety accessory of floating roof storage tank. With the help of certain reasoning and assumption, the calculation model of four working conditions is built. Referring to API 2000, the ventilation under various conditions is calculated, and finally the installation number of PVV is determined.

With the development of petrochemical equipment towards large scale and lightweight, the operating conditions of towers are becoming more and more complicated. The stress distribution is different at the connection between the skirt and the bottom of the tower under different types of loads. Therefore, how to choose the connection type correctly in the design has become the main concern for designers. In this paper, the finite element method is adopted to study the different connection types between the skirt and the tower, explore the characteristics of stress distribution and displacement under different types of loads and investigate the effects of different alignment to the connection. This provides reference for the design of vessels with skirt support.

Austenitic stainless steels are the most widely used materials in equipment and pipelines in oil refining and chemical industry, mostly used in corrosion-resistant and high-temperature-resistant workplaces. At high-temperature and high-pressure workplaces in refining and hydrogenation plants, type 321 and 347 stainless steel are often used in manufacturing process pipelines. However, many damage cases have occurred in these two types of austenitic stainless steels during welding, heat treatment and use. Based on the above reasons, this paper expounds the types of hot cracks in austenitic stainless steel, the causes and mechanism of intergranular corrosion and preventive measures, which can provide reference for relevant engineers in this field.

Heat exchanger device is the most widely used equipment in refining and chemical enterprises. The problem of corrosion leakage is the main hidden danger that troubles the long-term safe operation of oil refining units. Based on the corrosion cases of the exchanger in a refinery during one operation cycle and overhaul period, the exchanger corrosion was statistically analyzed from the aspects of corrosion types, corrosion locations and corrosion causes. And an in-depth study was conducted on the causes of corrosion and the main factors leading to corrosion. The anti-corrosion measures for heat exchange equipment were optimized from such aspects as material selection, manufacturing, operation control, and circulating water management. These provide useful reference for the corrosion protection of heat exchange equipment in refining and chemical enterprises.

Two heat exchange tubes in an exchanger tube bundle of a hydrocracking unit for reaction products and low pressure oil broke and came out. Various physical and chemical analyses show that the presence of Cl ion enrichment in the tube resulted in pitting corrosion on the inner wall. Under the effects of shell side fluid impact and heat exchanger structure, the tube bundle is easy to vibrate and needs to bear alternating loads. Under the action of cyclic stress caused by pitting corrosion and alternating load, the corrosion fatigue cracks on the inner wall of the heat exchange tube continued to expand, and eventually overload breakage occurred.

As one of the key equipment of hydrogenation unit, the heat exchanger for heat highpressure separation gas/mixed hydrogen has been in high temperature, high pressure and various corrosive environments for a long time. This heat exchanger has been repeatedly blocked by ammonium salt or under-deposit corrosion, resulting in unplanned shutdown of the unit. In this paper, the ammonium salt under-deposit corrosion and chloride stress corrosion of the heat exchanger (E1105) for heat high-pressure separation gas/mixed hydrogen unit containing high H2S content were analyzed in detail. The material selection of the heat exchanger in this corrosive environment was studied, and the specific material technical requirements and corrosion test requirements were put forward.

This paper expatiates on the operation of the feed compressor in the 50,000 Nm3/h hydrogen production unit of certain company. Aiming at such problems as temperature rise of thrust bearing and high-speed bearing of gearbox, carbon deposition of bearing bush and so forth, the internal structure of the equipment is analyzed through monitoring oil properties in use and unit condition. Then the effective solutions are put forward. After the implementation of the measures, the feed gas compressor has passed the maintenance and has been operated safely and reliably until now.

This paper introduces the basic situation and working principles of the centrifugal air compressor, the key units of Changling Branch of Sinopec Catalyst Co., Ltd.. It discusses in detail the management system and maintenance mode of the key units, and summarizes the management methods and experience. By adopting special maintenance management method, the long-term stable operation of the units is guaranteed and the equipment accident is eliminated. The management system and management method are worth popularizing in catalyst companies and other companies in petrochemical industry.

In order to ensure the longterm operation of ethylene plants, it is necessary to pay attention to and do well in equipment management, especially the daily maintenance and repair of cracking furnaces. Efforts should be made to improve the reliability of the safe operation of the equipment in two aspects including strengthening the routine maintenance of general equipment and the special maintenance of cracking furnaces. This paper summarizes some experience in the management of cracking furnaces in ethylene plants, which can provide reference for people of the same trade.