Horizontal buried tanks have been widely used because of their reliable performance in fireproof and antiexplosion as well as saving land resources and reducing construction cost. However, there are deficiencies in the present design and calculation methods for preventing failures of buried tanks under soil pressure. Based on rock and soil mechanics method, this paper studies the impacts of different parameters on the soil pressure acting on buried tanks. According to the results, it puts forward new calculation methods of soil pressure and soil weight load for buried tanks. The research results can provide a reference for the safety design of buried tanks.

This paper introduces two schemes of domestic 4,000 m3 propylene spherical tank made of Q370R and 07MnMoVR steel plates. According to the characteristics of stress analysis and design, it introduces in detail the ordering technical analysis indicators of steel plates, forgings, and welding rods of the two schemes, the structural design of the spherical tank, and the finite element stress analysis. The paper also expounds the special and improved requirements in the manufacture and installation process of spherical tanks. Meanwhile, it compares the cost of the two construction schemes and the cost performance is considered to be equivalent.

In order to respond to national call actively and make the emission values of pollutants (mainly refers to nitrogen oxides) meet the new environmental protection standards, the revamp project of low-nitrogen burner with substandard emissions is carried out. Three-step management method for low-nitrogen revamp of heating furnace based on green and environmental protection is formed, namely the new management modes of "case" planning, "pragmatic" design and practical "implementation". Through implementation of the new management mode, the successful completion of low-nitrogen revamp project of heating furnace is ensured; the effectiveness of the whole process is improved and the overall management level is enhanced. Meanwhile, the domestic revamp of low-nitrogen burner of ethylene cracking furnace is realized.

Magnetic pumps have the advantage of no leakage and are often used to pump flammable, volatile, toxic, valuable and other media that are not allowed to leak. The axial thrust force of magnetic pumps usually points to the inlet nozzle direction. Thrust bearing is commonly applied to withstand axial forces and overload axial thrust force is the main reason for thrust bearing failure. This paper introduces one type of axial self-balancing magnetic pump without thrust bearings which can adjust the position of the impeller automatically by throttling control to balance the axial force. Meanwhile, this paper simulates the pressure change in the balance chamber by using numerical simulation and verifies the feasibility of self-balancing magnetic pumps.

The pump shaft made of 17-4PH steel bent after having been placed for a period of time. Three samples were cut from the shaft for experiment testing. These samples were given solution treating at 1 020~1 060 ℃ and then aged at 540~560 ℃ with following air cooling respectively. After heat treatment, metallographic observation and Rockwell hardness test were carried out. For the pump shaft of 17-4PH precipitation hardening stainless steel, the dominant microstructure should be composed of lath martensite. However, through metallographic observation, it was found that there was a large number of retained austenite among the lath martensite, and lots of banded ferrite was observed in the axial section. The retained austenite has a tendency to transform into martensite at room temperature. When the pump shaft is placed improperly, the highly localized tensile stress would induce phase transformation which leads to shaft bending.

This paper introduces the structure and working principles of dryer in PTA plant. It analyses the causes for the failure such as material deposit, dew point corrosion and deformation of steam inlet and hydrophobic 'R' pipe during drying process. Meanwhile, combining with process conditions, the paper expounds the parameter adjustment and equipment structure characteristics and presents specific solutions. This ensures the long-term stable operation of the dryers and provides useful experience for the overhaul of dryers in similar units.

A hydrogen compressor, the key equipment of a petrochemical plant, started after overhaul. It shut down by vibration interlock at 600 revolutions per minute. Through spectrum analysis, it was considered that there was serious rub-impact fault between the dynamic and static parts of the compressor. The main cause of the fault was the wrong size of the half-wheel of the locomotive motor. A repair plan to rework the conductive contacts is carried out and then the compressor returned to normal operation. This paper expounds the mechanism vibration exceeding the allowable norm caused by rub-impact of dynamic and static parts of the compressor. It introduces an effective method for diagnosis of such failure through analyzing a rub-impact fault between the dynamic and static parts of a compressor. This method can accurately determine such faults and draw diagnostic conclusions, which is helpful for on-site maintenance guiding.

With the rapid development of economy, the consumption of chemical products in China has been increased year by year. In view of the corrosion properties of many chemical products, their storage containers must have good anti-corrosion performance, so the development of plastic storage tanks has also been rapid in China. However, there isn't sound system for the product standards of plastic storage tanks, which is undoubtedly a major hidden danger in the safety management of chemical products. This paper introduces the types and present standards of plastic storage tanks and puts forward suggestions to improve the standardization level of plastic storage tanks in China.

Eight 10×104 m3 crude oil storage tanks were constructed in one project. After water filling test of the tanks, it was found that the weld toe near the bottom plate of the large fillet weld inner side of #T13 tank cracked locally. This paper introduces the cracking of the fillet weld and the settlement deformation of the tank bottom plate during water filling test. It analyzes the residual stress in multi-layer and multi-pass welding of T-Welded joint and the additional stress in the fillet weld inside T-joints during water filling process. According to this, the paper established the basis of judgment for the cracking of fillet weld inside T-joints of storage tanks. And it is considered that the ring beam settlement plus welding residual stress caused stress concentration at the weld toe near the bottom plate of the inner side of the large fillet weld. Thus the local stress exceeded the tensile strength of steel plate, which was the main reason for the cracking.

This paper analyzes the forms and changes of material form and value form of fixed assets in use in petrochemical plants. It focuses on analyzing the operational effectiveness and methods for calculating the effectiveness of functional unit device as well as the necessity, economy and maintainability of equipment asset inspection and maintenance and analytical methods for calculating the maintenance costs. Then the paper presents some suggestions on strategies for operation and maintenance management of different types of equipment asset.

This paper takes the intensification of corrosion during the blending of Iraqi heavy crude oil in an atmospheric and vacuum distillation unit in a petrochemical refinery as the research object. Through analyzing the processing of Iraqi heavy crude oil by this unit and such units in other refining and chemical enterprises, and analyzing the components by laboratory methods, the reasons for the increase in corrosion rate during the processing of Iraqi heavy crude oil are found in the end. According to the reasons, the paper proposes the adjustment and corrosion protection measures for long-term processing of Iraqi heavy crude oil. And through taking these measures, the paper obtains a reverse verification of the correctness of the cause analysis.

This paper analyzes and studies the fracture reasons of 0Cr18Ni9 stainless steel heat exchange tube in methanol synthesis reactor by adopting such methods as chemical component analysis, mechanical performance test, microstructure analysis and SEM observation of fracture and energy spectrum analysis. The results show that the boiler feed water containing Cl-in the shell side of the reactor formed corrosive environment. Under the action of working stress and temperature, cracks initiated in the pitting corrosion region on the outer surface of tube and extended to the inner wall until penetrating. The fracture was characterized by cleavage fracture, which was intergranular and transgranular brittle fracture. The fracture reason of the heat exchange tube was chloride-induced stress corrosion cracking.

In order to design the spherical diaphragm seal structure of channel cover of certain after-cooler accurately, this paper calculates and analyzes the radial displacement of the cylinder short section of the high-pressure channel under internal pressure according to the theory of elasticity and the relevant analytical formulas in JB 4732—1995 standard. And the finite element model analysis is adopted to compare and verify the results. Then combining with the impacts of main operating condition parameters, the optimum structure of the diaphragm is determined. The results show through verification of engineering practice that the radial displacement calculated by the analytical formulas of thin film in the standard in this case has sufficient engineering accuracy; the spherical diaphragm has more potential radial elastic compensation than the planar diaphragm, which can improve the stress condition of sealing fasteners; the internal and external attachments of group welding on the short section of the channel have strengthening effect, but it will cause notable non-uniformity of radial displacement distribution along the circumference position, which is not conducive to sealing.

Medium pressure boiler feed pump is the auxiliary boiler water supply equipment of 60 t/a methanol plant of certain company. In the process of domestic substitution of fittings, the domestic substitution of mechanical seals used in the pump has repeatedly failed due to leakage. This paper finds out the causes and mechanism of the leakage by analyzing the leakage passages which may occur in the operation of mechanical seals one by one. Then it compares and checks the structure and main technical parameters between the mechanical seal substitution and the original BURGMANN (Germany) mechanical seals. The paper chases down the essential causes for the leakage failure of the domestic substitution of the mechanical seals. Then it puts forward some suggestions for improvement.