Please wait a minute...
Current issue
2024, Vol. 45,No. 4 Published:17 July 2024 Previous   
STATIC EQUIPMENT
Analysis and Suggestions on Stability of Large Silo Roof
Yang Xu, Chen Hao, Hu Weixuan
2024, 45 (4):  1-5,13.  DOI: 10.3969/j.issn.1006-8805.2024.04.001
Abstract ( 71 )  
In the conventional calculation of the thickness of the silo roof, only the average load per unit area is usually considered, including the basic snow pressure, the weight of the silo roof, etc., and the influence of the large weight of filters and pipe rack, platforms on the local stability of the silo roof has not been considered. This problem is more obvious in the calculation of large diameter silos. Therefore, a large silo with a diameter of 15 meters has been taken as an example in this paper. Finite element analysis has been carried out on the stability of its roof under the influence of filter weight and large pipeline load. It is verified that the large concentrated load has adverse effect on the stability of silo roof, and some reasonable suggestions in engineering design have been provided accordingly.
References | Related Articles | Metrics
ROTATING EQUIPMENT
Technology Development of Twin Screw Extruders in Polyolefin Plants
Zhao Siqi
2024, 45 (4):  6-13.  DOI: 10.3969/j.issn.1006-8805.2024.04.002
Abstract ( 86 )  
The extrusion equipment in Chinese domestic polyolefin plants is dominated by twin screw extruders which are categorized as two types in actual application: wholly intermeshing co-rotating type and non-intermeshing counter-rotating type. Currently, in most domestic projects, the extruders are still imported from abroad from three main manufacturers including Coperion GmbH from Germany, the Japan Steel Works, Ltd. and Kobe Steel Ltd. from Japan. The different origin leads to a variety of characteristics. This paper summarizes the technological development of twin screw extrusion equipment from the aforementioned three main manufacturers by starting with the oldest non-meshing anisotropic rotary twin-screw extruders. It reviews the application of melt gear pump in detail and briefly analyzes the relationship between gear pump application and energy consumption. Meanwhile, the paper gives a general introduction to the main technical data, such as production and power of main drive, and compares the stability between the two types of the units with the actual application of full-density polyethylene plant as an example. Moreover, combined with previous project experience, the wear between extruder screws and barrels is introduced and analyzed so as to provide assistance to users in selecting well-designed extrusion equipment with better cost performance.
References | Related Articles | Metrics
Dynamic Analysis of the Start-up Process of Centrifugal Compressor
Qiu Jianwei, Bai Liang, Zheng Xuepeng
2024, 45 (4):  14-19.  DOI: 10.3969/j.issn.1006-8805.2024.04.003
Abstract ( 55 )  
From the perspective of process assembly design, this paper divides the start-up process of centrifugal compressors in refining and chemical plants into three categories based on different process flows: 1) start at a relatively constant inlet pressure; 2) start at a relatively constant outlet back pressure; 3) start under settled pressure. Through building a numerical model for dynamic analysis and combining two different starting modes including speed regulation starting and direct starting of frequency motors, the typical starting process is analyzed and discussed. And the problems and design points of centrifugal compressor starting process are summarized. This can provide reference for optimizing process design and selecting compressor units.
References | Related Articles | Metrics
INDUSTRIAL FURNACE
Temperature Field Prediction Method of Industrial Heating Furnace Based on cGAN
Liu Jingming, Wang Yanli, Wang Ting
2024, 45 (4):  20-24.  DOI: 10.3969/j.issn.1006-8805.2024.04.004
Abstract ( 67 )  
The combustion process of industrial heating furnace is unstable and local over-temperature may occur at random locations, leading to furnace tube loss and damage. Since the heating furnace equipment is huge, it is difficult to measure the relevant physical quantity online. Therefore, this paper proposes to build a digital twin model based on the condition generation adversary-network on the standard industrial furnace heating model through which the temperature field of the heating furnace is predicted and the Unity 3D software is used for visualization to help the staff to optimize the combustion. The experimental results show that the cGAN network architecture can predict the temperature field, and the absolute error value of the temperature calculated at about 80% of the nodes within the test set is below 1% of the maximum temperature of the furnace, which is promising for the application.
References | Related Articles | Metrics
CORRODION AND PROTECTION
Study on Corrosion Behavior of Crude Oil Containing CO2 on FV520B Steel Impeller of Oil Pump
Yang Yang, Hou Yichen, Cao Yu
2024, 45 (4):  25-29,34.  DOI: 10.3969/j.issn.1006-8805.2024.04.005
Abstract ( 40 )  
CO2 is one of the key factors that causes serious corrosion of petroleum equipment and facilities. Aiming at the problem of serious pitting corrosion in the impeller of oil pump in CO2 flooding field, the corrosion rate, corrosion morphology and potential are analyzed comprehensively in this paper. The results show that the corrosion rate of FV520B steel increases exponentially with the increase of pipeline transport pressure and flow rate (R2>0.9), and the potential shifts negatively. With the increase of pipe pressure, the corrosion directivity of the specimen surface gradually disappears, indicating a distinct pitting area and a comprehensive corrosion area. With the increase of flow rate, the metal surface presents a grooved erosion morphology with small pits. This is due to cavitation under high pipe pressure and flow rate conditions.
References | Related Articles | Metrics
EMISSION REDUCTION AND GREEN ENERGY
Identification of Wind-induced Fatigue Life of Onshore Steel-concrete Hybrid Wind Turbine Tower
Xu Jiangtao, Shi Zhengui, Huang Cirong
2024, 45 (4):  30-34.  DOI: 10.3969/j.issn.1006-8805.2024.04.006
Abstract ( 33 )  
Wind-induced fatigue is a long-term accumulation process, and a single wind load event may not cause immediate damage to the structure. The interaction between different materials and components, stress concentration, local stress, and other factors affect the stress relationship of the tower, making it difficult to analyze the aerodynamic loads in different directions. Therefore, the accuracy of identifying fatigue life is poor. A method for identifying the wind-induced fatigue life of onshore steel-concrete hybrid wind turbine tower is proposed. The SESAM/GeniE module is adopted to convert the actual structure into a finite element model and calculate the aerodynamic loads in different directions of the tower. Then the comprehensive load value is obtained by combining the aerodynamic loads; by analyzing the relationship between external load and fatigue life of the tower and accumulating the comprehensive damage value, the identification result of wind induced fatigue life of the tower can be obtained. The experimental results indicate that when applying the identification method described in this paper to identify the fatigue life of steel-concrete hybrid wind turbine towers, the fatigue damage amount of towers at the same node also changes with the continuous increase of wind speed. The root mean square of the stress response between the identification results and the actual situation is low, indicating that this method can obtain high identification accuracy.
References | Related Articles | Metrics
INSPECTION AND MAINTENANCE TECHNOLOGY
On Repair Method of Local Damage of Enamel Stirring Shaft
Yan Junjie, Chen Zhen, Gao Ke
2024, 45 (4):  35-38.  DOI: 10.3969/j.issn.1006-8805.2024.04.007
Abstract ( 33 )  
This paper introduces the problem of local damage of enamel stirring shaft in a catalyst production and analyzes the causes of the problem. Combined with the actual production situation of the device, the repair method of enamel stirring shaft damage is explored and put into practice. Meanwhile, some suggestions are put forward to prevent damage of enamel equipment and for reasonable repair after damage. The above research results have successfully solved the problem of local damage of enamel stirring shaft affecting the normal production of the device as well as the problem of repairing the damage of enamel stirring equipment under severe working conditions. This provides a reliable technical method for the repair of this kind of equipment and it is worth of popularization in petrochemical industry.
References | Related Articles | Metrics
Cause Analysis of Frequent Cracking of Upper Tail Pipe of Hydrogen Production Reformer and Countermeasures
Lyu Hongxia, Pan Xiaoming
2024, 45 (4):  39-44.  DOI: 10.3969/j.issn.1006-8805.2024.04.008
Abstract ( 53 )  
After the reformer for hydrogen production in certain refining enterprise was upgraded and revamped in 2010, five cracks have occurred in the reinforced joints of different furnace tubes and in the weld junction of the upper tail pipe, resulting in unplanned shutdown of the hydrogen production plant. Through in-depth analysis of the operating environment, high-temperature hydrogen corrosion, thermal expansion stress, structural stress, dissimilar steel welding, spring support hangers, etc., it was found that the leakage was mainly due to the stress relaxation cracking in the local high-stress area of the weld connecting the reinforced joints and the upper tail pipe, and meanwhile, the process parameters were not strictly controlled, which increased the cracking speed. In 2021, through the implementation of furnace tube material upgrading, stabilization of process operating environment, strict control of construction quality and other measures, there has been no more cracking; the safety hazards during the operation of the furnace tube have been completely eliminated; and the intrinsic safety of the equipment and the long-cycle operation of the device have been guaranteed.
Related Articles | Metrics
Analysis and Research on the Insufficient Refrigeration Effect of Polyolefin Recovery Refrigeration Unit
Wang Zhijun, He Bao
2024, 45 (4):  45-49.  DOI: 10.3969/j.issn.1006-8805.2024.04.009
Abstract ( 37 )  
Refrigerating unit is a key equipment in polyolefin industry which recovers the copolymer and isopentane in the gas discharged from the reactor. The operating condition of the refrigerating unit directly affects the unit consumption of materials. There are many factors affecting the refrigeration capacity of refrigeration units. This paper analyzes and studies the problems of expansion valve failure and improper superheat setting, suction filter blockage, water contained in the system, excessive or insufficient refrigerant charging, load control system failure, leakage between high and low pressure systems, oil film generated by heat exchanger, changes in process conditions. It proposes some relevant preventive measures so as to avoid the decrease of refrigeration capacity of refrigeration units caused by the above reasons and ensure the safe, efficient and stable operation of the refrigerating units.
References | Related Articles | Metrics
Energy Saving Revamp and Installation of CO2 Compressor Driving Steam Turbine
Song Wenming
2024, 45 (4):  50-54.  DOI: 10.3969/j.issn.1006-8805.2024.04.010
Abstract ( 25 )  
The driving steam turbine of an imported CO2 compressor unit has been in operation for 45 years and problems such as cylinder deformation, low efficiency and bearing wear have occurred. In order to solve these problems, it was decided to replace the machine with a new domestically produced one. This paper analyzed and summarized the process of energy-saving revamp and installation of the compressor driving steam turbine. Through the project of energy-saving revamp and installation of CO2 compressor driving steam turbine, this paper studied the similarities and differences in structure design between the new and old steam turbines. Meanwhile, aiming at the large four-shafting compressor unit, it also studied how to realize the high precision (0.01 mm class) positioning of the steam turbine center in the three coordinate directions of front and rear, high and low, left and right under the condition of keeping the three shafting of the compressor motionless and taking the low pressure cylinder as the datum. This method was adopted to complete the reverse and precise installation of the new steam turbine (total weight 22 tons).
Related Articles | Metrics
On Reducing Blockage Rate of Key Pumps in Amine Liquid System after Overhaul of Natural Gas Purification Combined Plant
Han Qiong, She Xue, Che Chunli, Wu Yunsheng
2024, 45 (4):  55-59.  DOI: 10.3969/j.issn.1006-8805.2024.04.011
Abstract ( 38 )  
After the overhaul of certain natural gas purification complex, the key pump (P-102A/B) of the amine liquid circulation system was frequently blocked, which greatly increased the operating cost of the device and the labor intensity of the operators. In order to ensure stable production at the initial stage of the plant after the start-up of the device after the overhaul, the causes for the frequent blockage of the P-102A/B pump were thoroughly analyzed, verified and confirmed at the site. And it was determined that the dirty equipment and pipelines after the overhaul were the main influencing factors leading to the aforementioned problems. In addition, a corresponding countermeasure scheme was formulated and implemented from consideration of effectiveness, practicability and economy, which ultimately achieved the goal of reducing the blockage rate of P-102A/B, reduced the amount of utility media required to clean the filters, and effectively avoided the problems of natural gas venting and excessive tail gas emissions caused by blockage of double pumps.
References | Related Articles | Metrics
EQUIPMENT MANAGEMENT
On Standardized Management of Shutdown and Overhaul of Large-scale Unit Groups in Petrochemical Plants
Shi Yaolin
2024, 45 (4):  60-66.  DOI: 10.3969/j.issn.1006-8805.2024.04.012
Abstract ( 39 )  
The shutdown, overhaul and revamp of petrochemical plants is a complex system engineering. The overhaul of compressor units in this project is a key project and a core project that affects the smooth operation of the equipment. The shutdown of multiple device series involves dozens of units, and the workload and difficulty of such overhaul are even greater. Relying on the standardized shutdown and overhaul management procedure of a large enterprise, this paper summarizes the shutdown and overhaul management strategy of large unit groups and developed a set of effective standardized management method. The method has been implemented in the 2023 overhaul with good results and can provide reference for the shutdown and overhaul of similar devices.
References | Related Articles | Metrics
Online office
Information
Supervisor: China petrochemical corporation
Sponsor: China petrochemical engineering construction co. LTD
Address: 21 anhuili anyuan, chaoyang district, Beijing
Tel:010-84877478
E-mail:syhgsbjs@sei.com.cn
ISSN:1006-8805
CN: 11-2469/TE