Additive manufacturing (3D printing) technology is a revolutionary technology integrating digital manufacturing, intelligent manufacturing and green manufacturing. It is very much in line with the strategic policy of the petrochemical field, and has shown great potential in improving production efficiency, improving manufacturing accuracy, reducing manufacturing costs and improving equipment quality. It is very consistent with the strategic policy of the petrochemical field, and has shown great potential in improving production efficiency, improving manufacturing accuracy, reducing manufacturing costs and improving equipment quality. This paper expounds the industrial policies related to additive manufacturing at home and abroad and points out that additive manufacturing technology has become an important strategic means to enhance the international competitiveness of manufacturing industry in each country. The characteristics of additive manufacturing technology were analyzed, and the application scenarios of additive manufacturing technology were discussed especially in the field of petrochemical industry. The potential advantages of additive manufacturing technology in design and development, equipment repair, equipment quality improvement and equipment reduction design were expounded, as well as its development prospects in the field of petrochemical industry.

Over-temperature and overload often occur when the hydrogen compressor is tested with nitrogen before it is put into use. In this paper, the power of the hydrogen compressor during the nitrogen test was calculated quantitatively according to the thermodynamic calculation, and the power change caused by the mass flow change and temperature change was analyzed. Meanwhile, the expansion work and non-expansion work in the compression process were analyzed specifically according to the relevant theories, and then the power change caused by the change of the working medium type was analyzed and calculated. The reasons for the over-temperature and overload that tends to occur during the nitrogen test were found and analyzed according to the relevant theories.The conclusions of this study may provide some reference for avoiding the above phenomenon.

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.

This paper introduced the advantages of the stepless capacity regulation system and its influence on the reciprocating compressor firstly. Then it analyzed the concept and calculation method of the motor current pulsation. Through an example,the paper calculated the torque of the compressor crankshaft and the motor stator current pulsation under different loads when using the stepless capacity regulation system. It was concluded that as the capacity decreased, the motor current pulsation increased accordingly. Therefore, it is suggested that when the stepless capacity regulation system is newly installed, the reverse angle, rotation unevenness and stator current pulsation of the drive motor should be checked for the compressor unit. This paper is informative for the operation, selection calculation and check calculation of compressors.

Corrosion and leakage occurred several times during the operation of the regeneration tower of a petrochemical gas desulfurization unit, which seriously affected the normal production of the unit. A systematic physicochemical analysis of the corrosion samples was carried out by means of spectrometer, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), and meanwhile, the flow field in the tower was simulated and analyzed by applying Computational Fluid Dynamics (CFD) simulation software.The results show that the element composition of the component meets the requirements of the national standard. The main component of corrosion products is FeS2. Affected by the internal structure of the tower and production process on the flow field, wet H2S corrosion and erosion corrosion are easy to occur locally in the system, which is the main cause of corrosion. According to the corrosion mechanism, the corresponding optimization measures and countermeasures were put forward.

9Ni steel has good mechanical properties, weldability and low temperature toughness and has been widely used in LNG cryogenic storage tanks.Yet due to the existence of residual weld height in LNG storage tanks and the different ray absorption of weld and base material, it isoften difficult for the substrate quality to meet the standard requirements, which brings great difficulties to radiographic testing. By comparing and analyzing the imaging effects of digital radiography and conventional film technology, it was concluded that the imaging quality of digital radiography technology is better than that of film technology.Then through reasonable process settings, the testing problem of 9Ni steel welded joints was solvedsuccessfully.In addition, taking an LNG cryogenic storage tank with a volume of 200,000 m³ as an example, this paper also introduced the application of digital radiography technology in LNG installation projects, and the application results show that digital radiography has significant advantages in terms of imaging quality and testing time, and is expected to be further popularized and applied.

In response to the weld cracking failure in a high-pressure steam turbine inlet system, this paper made an analysis from such aspects as metallographic microstructure morphology, fracture morphology, composition distribution and so on. Meanwhile, coupling with the results of physical and chemical properties tests, it identified the mechanism leading to the occurrence and expansion of the weld cracks. Andthe main causes of weld cracking were considered to be, in descending order, high-temperature creep, fatigue damage, excessive stress, low weld toughness, and weld defects. Aiming at the above causes of weld cracking, prevention strategies such as optimizing the stress distribution of the turbine inlet system, improving the welding and heat treatment process, strengthening operation control, adopting advanced testing technology, optimizing inspection and so forth have been adopted, which haveeffectively controlled the operational safety risks of high-pressure steam turbines.

The heat exchange tube bundle is the key component of ORV (Open Rack Vaporizer) equipment. The LNG in the heat exchange tube bundle exchanges heat with the seawater flowing in the shape of water curtain on the outer surface to complete the gasification process of LNG. This paper analyzes the damage mechanism of the heat exchange tube bundle, and provides a method for calculating the optimal replacement cycle of heat exchange tube bundles based on the principle of minimizing the total cost incurred by heat exchange tube bundle failure and periodic planned shutdown for tube bundle replacement. The results show that the main factors of damage and failure of heat exchange tube bundle are electrochemical corrosion, microbial corrosion, seawater quality, seawater erosion, cracking and so forth. Taking an LNG terminal as an example, the optimal replacement cycle of ORV heat exchange tube bundle at the terminal is obtained byadopting the calculation method described in the paper. The results of this study can provide a theoretical basis for the maintenance and replacement of ORV heat exchange tube bundles.

The tube layout is one of the most important and most easily overlooked factors affecting the flexibility of the flexible thin tube sheet. The rationality of the tube layout directly determines the service life of the flexible thin tube sheet.Different finite element analysis models were established for the flexible thin tube sheet in a waste heat boiler and were analyzed under multiple working conditions to obtain various stress levels and stress distribution of the flexible thin tube sheet. According to the main parameters of the tube layout including the tube pattern, the tube pitch and the limit circle diameter of tube layout, the influence rules of various factors on the stress intensity of flexible thin tube sheet were obtained. The analysis results show that the stress level of flexible thin tube sheet can be effectively improved by optimizing the tube layout reasonably. The results are instructive for the engineering design of flexible thin tube sheet.

The problem of high energy consumption and load mismatch occurred in the cracking gas compressor unit after the "1.1 million tons reconstruction and expansion" of the ethylene plant in one company. Aiming at these problems, the internal efficiency and energy consumption of the cracking gas turbine were calculated by real-time operation parameters and compared with the standard parameters provided by the manufacturer. The work done by the compressor was calculated by ASPEN PLUS simulation, and then the mechanical efficiency of the unit was obtained. The flow area of the steam turbine and the real-time working condition of the condenser were analyzed by adopting the "Freugel formula" and the fitted standard curve of condenser. The results show that the flow area of the high pressure part of the turbine decreases and the internal efficiency decreases, which leads to the deviating of the real-time working condition of the condenser from the characteristic curve, resulting in high energy consumption of the unit.

The fault monitoring and early warning of large pumps is significantly important to the safety of LNG operation. Traditional monitoring methods mainly rely on vibration alarm, but some faults will not cause vibration over-limit. And once the vibration exceeds the limit, it will usually cause interlock shutdown, which will directly affect production. In this paper, a fault early warning algorithm model based on axis orbit feature identification was constructed for Tangshan LNG seawater pumps. The monitoring signals of existing vibration sensors were used in the model to analyze the distribution features of the pump axis orbit. Base on this, the normal running feature index was constructed. When the axis orbit index deviates, a fault alarm will be issued to the operator to start an inspection process. Practices have proved that this method can make full use of the monitoring data to achieve early identification of seawater pump failures and provide effective support for reducing unplanned outages of seawater pumps.

The complete set of heating and power generation equipment composed of steam turbines and boilers, generators and the ancillary equipment is mostly used for group heating or self-supply heating and power stations in oil refining, chemical, light textile, paper making and other industries. It can provide power for enterprises and improve the economic efficiency of the heating systems. Taking the No.1 turbine-generator of the self-supply heating and power station of one domestic mega refining and chemical enterprise as an example, this paper introduced the revamping scheme of this unit. By redesigning the flow-through section of the original body structure of the extraction condenser and converting the extraction condenser unit into a backpressure unit, the economic loss caused by the long-term inefficient operation of the low-pressure section of the turbine under extraction condition can be avoided and the loss of the cooling source can be eliminated completely. After the revamp of the turbine, the consumption of the comprehensive standard coal of the CHP (Cogeneration, combined heat and power) was reduced to below 150 g/(kWh), which shows significant economic benefits.

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.

In view of the structure and characteristics of coke tower wrapped insulation and combining with the overall settlement of coke tower (C2101/2) on-site insulation of a certain enterprise, this paper obtained the causes of general overheating of coke tower insulation through on-site inspection and infrared scanning analysis. Then it proposed corresponding solutions. The paper also analyzed and discussed the technologies related to the installation process of coke tower wrapped insulation. After dismantling and replacing the tower insulation with the improved construction technology, the over-temperature has been controlled effectively, which has guaranteed the long-term, high-efficiency, safe and smooth operation of the coke tower system. This case can provide reference for the construction quality improvement of coke tower wrapped insulation.