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Hydrodeoxygenation of Guaiacol as a Model Compound of Lignin: A Review
Qichang Guo, Jingbo Mao, Chunyu Liu, Yufeng Jia, Jinxia Zhou
Abstract1173)   HTML76)    PDF (647KB)(2229)      

Guaiacol (GUA) is extensively used as the model compound in catalytic studies of lignin, a most abundant renewable aromatic resource in nature. However, GUA is not easy to obtain good activity and selectivity in the hydrodeoxygenation reaction due to its complex structure with various reaction possibilities. So far, researchers have done great efforts to develop efficient catalysts and reaction processes for breakthroughs. This paper reviewed the research progress of transition metal catalysts and noble metal catalysts for hydrodeoxygenation of GUA, and discussed the reaction pathways and the factors which may affect the catalytic behavior, particularly focusing on their catalytic conversions of GUA to phenol or cyclohexanol through CAR-O bond cleavages and aromatic ring saturation. A prospect regarding the future research directions on the catalyst improvement and reaction process optimization were also presented.

2022, 42 (5): 1-12. DOI: 10.3969/j.issn.1672-6952.2022.05.001
Electrochemical Behaviors of Ferrocene Using Cyclic Voltammetry
Qiao Qingdong, Li Qi
Abstract2832)      PDF (1784KB)(2100)      
The ferrocene shows definite aromatic and redox properties, which can used as a switch model substance. In alcohol solution of lithium perchlorate, the redox reaction process of ferrocene is quasi-reversible, in which the electron transfer number determined is 1, and the diffusion coefficients of ferrocene ion (Fc+) and Fc are 2.24×10-3 cm2/s and 4.34×10-3 cm2/s, i.e. the diffusion velocity of Fc+ is faster than Fc. The standard rate constant tested is 2.79 cm/s.
2014, 34 (3): 5-7. DOI: 10.3696/j.issn.1672-6952.2014.03.002
Research Progress of Conductive Polymer Flexible Strain Sensing Materials
Hua Li, Yutian Zhu, Guiyan Zhao
Abstract687)   HTML    PDF (400KB)(1791)      

With the rapid development of human?computer interaction, electronic skin, wearable electronics and other emerging fields, flexible strain sensing materials as one of the core components have become the hot spot of the current research. The conductive polymer composites composed of conductive material and flexible polymer have the advantages of good flexibility, light weight, easy processing and forming, and the conductive property of the material changes under strain stimulus, so it can be used as flexible strain sensing material. This paper reviewed the classification and characteristics of flexible strain sensing materials based on conductive polymer composites, introduced the strain response mechanism of different sensing materials in detail, and summarized the factors that affect the strain sensing performance of conductive polymer composites.

2022, 42 (2): 44-49. DOI: 10.3969/j.issn.1672-6952.2022.02.007
Dynamic Mechanical Properties and Constitutive Model of Double Phase Steel HC420/780DP
Zhentong Dong, Xianming Meng, Jianjun Guan, Yan Zhao
Abstract1469)   HTML21)    PDF (1683KB)(1746)      

High?speed tensile tests of HC420/780DP dual?phase steel at strain rates of 0.001,0.100,1.000,10.000,100.000 s-1 and 200.000 s-1 were carried out. The dynamic mechanical behavior of the materials under different strain rates was studied. The true stress?strain curves of HC420/780DP at different strain rates were obtained, and the fracture elongation, tensile strength and flow stress were analyzed. The results show that the flow stress, yield strength and tensile strength of HC420/780DP dual?phase steel increased with the increasing strain rate. Based on the modified Johnson?Cook constitutive model, the dependent plastic deformation constitutive model versus HC420/780DP dynamic strain rate was established. The fitting results of the optimized constitutive equation are in consistent with the curves of experimental results.

2023, 43 (1): 61-66. DOI: 10.12422/j.issn.1672-6952.2023.01.011
Research Progress on Modification of Bismuth Oxide as Visible Light Photocatalyst
Yonghui Zhang, Xuebing Chen, Jing Zhang
Abstract4661)   HTML    PDF (1443KB)(1745)      

As an important semiconductor photocatalytic material, bismuth oxide (Bi2O3) is considered as a promising visible photocatalyst due to its special electronic structure and excellent visible light response performance. It displays a good application prospect in photocatalytic treatment of wastewater. However, the application of Bi2O3 is limited by its low photocatalytic performance, therefore, Bi2O3 pholocatalyst with superior performance is expected to be obtained by modifying methods by the researchers. In this review, a series of modification methods, such as surface morphology regulation, surface modification, metal ion modification and semiconductor combination, are summarized. Then, the future development of modified Bi2O3 photocatalytic materials is prospected.

2021, 41 (6): 1-8. DOI: 10.3969/j.issn.1672-6952.2021.06.001
Applications of Covalent Organic Frameworks in Li⁃S Battery Separators
Yuluan Zhang, Can Guo, Luanhua Zhou, Xiaoman Yao, Yiwen Yang, Huifen Zhuang, Yirong Wang, Yifa Chen, Shunli Li, Yaqian Lan
Abstract480)   HTML24)    PDF (1359KB)(1575)      

Due to the high storage capacity and multiple electron?transfer chemistry of sulfur (S), Li?S battery with virtues of high theoretical capacity/energy density, eco?friendliness and abundant supply has been considered as one of the most promising candidates for next?generation battery systems. The capacity of Li?S battery is much higher than that of traditional metal oxide cathode?based lithium?ion battery, which is regarded as the highest capacity of solid?state cathode?materials at current stage. As a vital component of Li?S battery, separator plays a profound role in resolving crucial issues (e.g., shuttling effect, volume expansion, poor conductivity and metal dendrites, etc.) of Li?S battery. So far, some pioneering works have been reported in the exploration of separators for Li?S battery. On this basis, covalent organic frameworks (COFs), possessing the advantages of low density, high porosity, well?defined structure, designable structure and functions, is a kind of potential materials for the functional modification of Li?S battery separators. This review will summarize the reported works about COFs in Li?S battery separators including their structural characteristics, preparation?methods, application forms and battery properties. It will also provide a brief perspective for the applications of COFs in Li?S battery separators and hope that it might give new insights for scientists in related fields.

2023, 43 (4): 19-29. DOI: 10.12422/j.issn.1672-6952.2023.04.004

Research of Liquid Paraffin-Emulsion

Duan Yueying, Cong Yufeng, Huang Wei, Zhao Hongli, Tang Dong, Bai Shuangfu, Guo Jinpeng, Gao Zhu
Abstract937)      PDF (925KB)(1553)      

Paraffin emulsion was prepared from liquid paraffin by the means of adding coemulsifier. The effects of the emulsifie species and their dosages, water dosage, emulsifying temperature, and emulsifying time on the paraffin emulsion properties were studied. The results showed that composite emulsifiers could provide better performance for the paraffin emulsion. The influencing factors can be arranged in orderwater dosage>emulsifier dosage>emulsifying temperature>emulsifying time. Stable paraffin emulsion can be prepared under the optimum conditionsm(glycerol monostearate)/m(Tween80)=34, emulsifier dosage 0.9%,emulsifying temperature 85 ℃,emulsifying time 50 minwater dosage 62.0 and stirring speed 1 100 r/min. The experimental result indicated that the liquid paraffinemulsion had better stability density and dispersibility.

2016, 36 (5): 6-9. DOI: 10.3969/j.issn.1672-6952.2016.05.002
Numerical Simulation of Leak Diffusion and Failure Consequences of High⁃Pressure Hydrogen⁃Doped Natural Gas Pipelines
Biao Gao, Ruotong Zhao, Chuting Kuai, Mengyu Hu, Guofu Wang
Abstract571)   HTML32)    PDF (1360KB)(1532)      

For the under?expansion jet generated after the failure leak of high?pressure pipeline, the Birch theory model was used to replace the actual pipeline leak hole with a pseudo?source. Under different conditions of Hydrogen Blend Ratio (HBR), leak hole size and pipeline running pressure, the concentration field distribution, explosion hazard boundary and explosion hazard range of hydrogen?doped natural gas pipelines after leakage and diffusion were studied. The results show that with the increase of HBR, the aggregation of HDNG after leak diffusion is reduced, the explosion hazard range is gradually decreased and the distal hazard is reduced. However, the increase of HBR shifts the position of explosion hazard boundary downward and increases the proximal hazard. With the increase of leak hole size and pipeline pressure, it will increase the influence area of HDNG after leak diffusion, which will move the explosion hazard boundary position upward and increase the explosion hazard range gradually and increase the distal hazard.

2023, 43 (2): 60-66. DOI: 10.12422/j.issn.1672-6952.2023.02.010
Preparation of Titanium Dioxide by Direct Calcination and Its Oxidative Desulfurization Performance
Longchang Zhou, Hanlin Liu, Xiuping Li, Rongxiang Zhao
Abstract1071)   HTML    PDF (1612KB)(1504)      

Titanium sulfate was used as a raw material, and a titanium oxide (TiO2) was prepared by direct high?temperature calcination in a muffle furnace. FT?IR, XRD, UV?Vis, SEM were used to characterize the structure of the catalyst. The results show that the direct calcination method can prepare anatase titanium dioxide and apply it to the oxidative desulfurization of dibenzothiophene. Using acetonitrile as the extractant and titanium oxide as the catalyst, the oxidation method was used to remove dibenzothiophene from the simulated oil. The effects of catalyst dosage, reaction temperature, n(H2O2)/n(S), and different sulfur compounds on the desulfurization effect were investigated, and the recycling performance of the catalyst was also investigated. Under the optimal desulfurization conditions, the desulfurization rates of dibenzothiophene, 4,6?dimethyldibenzothiophene, benzothiophene, and mixed diesel are 99.5%, 35.6%, 65.0%, and 53.4%. After the catalyst was recycled five times, the catalytic desulfurization effect was still as high as 90.3%.

2021, 41 (5): 17-22. DOI: 10.3969/j.issn.1672-6952.2021.05.003
Research Progress of Porous Solid Materials for CO 2 Adsorption and Removal
Siqi Tong, Weiwei Jian, Qiuyan Hai, Weixin Xie, Yi Sun
Abstract1517)   HTML    PDF (672KB)(1434)      

As the greenhouse effect becomes gradually significant, CO2 capture and storage (CCS) has turned into a potential emission reduction measure, and the adsorption method of CO2 capture is one of the most promising technologies. Porous solid adsorbents have attracted widespread attention due to their excellent CO2 adsorption performance. This review focused on the research of CO2 removal by adsorption. Five different adsorption materials were introduced, and the main factors affecting CO2 adsorption were summarized, as well as the adsorption performance of modified materials. The results show that the changes of temperature, pressure, and pore structure can affect the physical adsorption properties of the materials; reduction, oxidation, and metal ion loading modification can improve the CO2 adsorption performance by Changing the type or number of functional groups on the surface of the material.

2022, 42 (2): 30-37. DOI: 10.3969/j.issn.1672-6952.2022.02.005
Experimental Study on Natural Gas Hydrate Slurry Flow in Oil⁃Based System
Zhen Pan, Lihe Zhang, Jiangtao Hao, Jian Zhu, Song Yuan
Abstract464)   HTML12)    PDF (4502KB)(1378)      

In the multiphase flow pipeline transportation system, in the process of hydrate slurry flow, rugged terrain will be encountered. At this time, the use of inclined pipeline is particularly important. Therefore, the influence of the flow characteristics of gas hydrate slurry in the inclined pipe on the blocked pipeline was studied. The hydrate plugging experiment of oil + natural gas in oil?based system was carried out on the low?temperature and high?pressure visual hydrate experimental loop, and the effects of initial pressure, initial flow and other factors on the flow and plugging time of natural gas hydrate slurry were explored. At the same time, the micro changes of hydrate particles in the process of hydrate formation, flow and pipe plugging were analyzed by real?time online particle tester. The experimental results show that with the increase of initial pressure, the induction time, formation time and slurry flow time of natural gas hydrate are shortened, and the pipe plugging trend of natural gas hydrate increases. With the increase of initial flow rate, the induction time, formation time and slurry flow time of natural gas hydrate are prolonged, and the pipe plugging trend of natural gas hydrate is reduced. Finally, the process from hydrate formation to pipe plugging and the plugging mechanism were analyzed. The research results of gas hydrate plugging pipelines in oil?based systems show that the probability of gas hydrates blocking pipelines can be effectively reduced by reducing initial pressure and increasing initial flow rates in oil?based systems. The research results can provide theoretical reference and basis for maintaining and ensuring the safe flow of natural gas hydrate in pipelines.

2022, 42 (5): 62-70. DOI: 10.3969/j.issn.1672-6952.2022.05.010
Optimal Consensus of Heterogeneous Multi⁃Agent Systems Based on Q⁃Learning
Weiran Cheng, Jinna Li
Abstract478)   HTML20)    PDF (674KB)(1327)      

This paper proposes a model?free control protocol design method based on off?policy reinforcement learning for solving the optimal consensus problem of heterogeneous multi?agent systems with leaders. The dynamic expression of local neighborhood error is complicated for the heterogeneous multi?agent systems because of its different system state matrices. Compared with the existing solution of designing observer for distributed control of multi?agent system, the method of solving global neighborhood error state expression proposed in this paper reduces the complexity of calculation. Firstly, the dynamic expression of global neighborhood error of multi?agent system constructed from augmented variables is established. Secondly, the coupled Bellman equation and HJB equation are obtained through the value function of quadratic form. Then, the Nash equilibrium solution of the multi?agent optimal consensus is obtained by solving the optimal solution of the coupled HJB equation, and the Nash equilibrium proof is given. Thirdly, an off?policy Q?learning algorithm is proposed to learn the Nash equilibrium solution of the multi?agent optimal consensus. Then, the proposed algorithm is implemented by using the critic neural network structure and gradient descent method. Finally, a simulation example is given to verify the effectiveness of the proposed algorithm.

2022, 42 (4): 59-67. DOI: 10.3969/j.issn.1672-6952.2022.04.011
Correlation Analysis among Real Estate Development Investment ,GDP and House Price in China
YuDan, QinJie, FangDan, WangBo, KuaiChuting
Abstract1347)      PDF (1686KB)(1327)      
In recent years, due to excessive freedom, some real estate developers' speculation and other reasons, the real estate market prices drift influenced national welfare and the people's livelihood. So this problem needed to be solved. In order to explore the deep-seated reasons affecting China's housing prices, study the irrationality of housing prices and solve the problem, the time series data was selected from 2005 to 2014, using E-view analysis software, through cointegration test, Grainger causality test and generalized impulse response function method, analyzes the impact of China's GDP and real estate development investment to changes in prices. The research results showed that China's GDP had long-term stable equilibrium relationship of prices, and price influence of real estate development and investment gradually weakened with the passage of time.  
 
2017, 37 (1): 70-74. DOI: 10.3969/j.issn.1672-6952.2017.01.014
Research Progress on the Application of Nanomaterials in Water Plugging and Profile Control Agents⁃Review
Jinmei Ye, Lu Ma, Yian Zhao, Yuanyuan Yao, Jie Wen, Lianhong Zhang, Hui Zhang
Abstract758)   HTML    PDF (1003KB)(1258)      

In recent years, with the continuous development of nanotechnology and oilfield development technology, nanomaterials have been widely used in water shutoff and profile control agents and have achieved varying degrees of development. This article reviews the research progress and latest achievements of nanomaterials in water shutoff and profile control from four aspects: foam, polymer gel, emulsion, and superfine cement slurry, and analyzes the use of nanomaterials in water shutoff and profile control agents. The mechanism of action and its influence on the law. It is found that after adding nanomaterials to the system, it can interact with the water shutoff profile control agent by its physical and chemical properties such as small size and large surface area so that the stability, strength, and strength of the water shutoff agent can be improved. The temperature and salt resistance is significantly improved, thereby effectively improving the water shutoff rate and oilfield recovery rate. In addition, from the perspective of water shutoff agent research and development, various problems in current research in this area are pointed out, to provide a reference for the research and application of nanomaterials in water shutoff profile control agents.

2022, 42 (2): 38-43. DOI: 10.3969/j.issn.1672-6952.2022.02.006

The Progress of Sodium-Ion Battery Anode Material

Zhang Jie, Yang Zhanxu
Abstract911)      PDF (1163KB)(1247)      

     Sodium ion batteries have attracted tremendous attentions due to its rich resources, low cost, high efficiency and good chemical stability, and can satisfy people's demand for energy in the new era, which are considered a top alternative to lithiumion batteries. The research progress on sodium ion battery anode materials are reviewed in details in this paper, including carbon-based materials, low voltage metal phosphates, the sodium storage alloys, metal oxides, titanium-based materials, and other negative electrode materials. Then the characteristics of anode materials are discussed. Finally, some future directions for sodiumion battery anode materials are pointed out.

2016, 36 (1): 7-11. DOI: 10.3696/j.issn.1672-6952.2016.01.001
Research Progress of Reaction Mechanism of Carbon Dioxide Hydrogenation to Methanol
Wang Yan, Wang Xiaoyue, Cao Ruiwen, Ban Hongyan, Li Congming
Abstract2417)   HTML    PDF (3312KB)(1223)      
With the rapid development of industry, the negative impact of the use of fossil fuels on the ecological environment is becoming more and more prominent. Among them, CO2, as the main greenhouse gas, causes serious harm to global climate change. The selective hydrogenation of CO2 to methanol is one of the important ways to solve the greenhouse effect, develop green energy and realize sustainable economic development. Copper⁃based catalysts are widely employed for CO2 hydrogenation to methanol due to their excellent catalytic performance and low cost. The difference in reaction mechanism is due to the highly adjustable chemical and electronic properties of copper⁃based catalysts, resulting in the different catalytic performance. This article reviewed the representative reaction mechanism of selective hydrogenation of CO2 to methanol over copper⁃based catalysts was presented, aiming to provided a theoretical guidance for the design of efficient and stable copper⁃based catalysts.
2020, 40 (4): 11-20. DOI: 10.3969/j.issn.1672-6952.2020.04.003
Synthesis,Characterization and Catalytic Reaction of UiO-66-NH 2 Supported Pd Catalyst
LiXiang,ZhangYanmei,ZhangJing,et al
Abstract899)      PDF (3456KB)(1199)      
The heterogeneous bifunctional catalyst UiO-66NH 2/Pd with Pd nanoparticles has been prepared on metal-organic framework of UiO-66-NH 2 using the impregnation and reduction method. The materials were characterized by X ray diffraction (XRD), Fu Liye transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The resulting material of UiO-66-NH 2/Pd was further evaluated as a potential bifunctional heterogeneous catalyst for olefine hydrogenations and Knoevenagel condensation between benzaldehyde and ethyl cyanoacetate. The results showed that the weight percent of Pd in UiO-66-NH 2/Pd was 3.4% and the average Pd particle size of was about 1 nm. The introduction of Pd nanoparticles did not change the framework integrity of UiO-66-NH 2. The resulting bifunctional catalyst of UiO66NH2/Pd was first tested in olefine hydrogenations and the results demonstrated that the material was active and stable as a heterogeneous catalyst. It could be reused for at least 6 times without significant loss of its catalytic performance in styrene hydrogenation. Remarkably, its structure was stable during the reactions. Furthermore, it also showed good activity and recycle stability in Knoevenagel condensation between benzaldehyde and ethyl cyanoacetate.
2017, 37 (1): 8-13. DOI: 10.3969/j.issn.1672??6952.2017.01.002
Study on the Mechanism of the Novel Extended Surfactants on Reducing the Interfacial Tensions
Xiangdong Jiang, Zhaohui Zhou, Lu Zhang, Guiyang Ma
Abstract443)   HTML12)    PDF (2114KB)(1197)      

To investigate the structure?function relationship of novel extended surfactants and the mechanisms of reducing interfacial tensions (IFTs) at oil?water interface, the interfacial tension values of 13?P series 13?P(I?C13(PO) x S,x=5,10,15,20)with different concentrations of NaCl and n?hexane to n?tetradecane at fixed concentration were measured by rotary drop interfacial tension meter. The result indicates that at higher numbers of PO(x=15,20), the nmin values become higher with increasing concentration of NaCl. At lower numbers of PO(x=5,10), the nmin values become lower with increasing concentration of NaCl. It reflects two mechanisms on reducing IFTs: Hydrophilic lipophilic equilibrium effect and hydrophilic hydrophobic group in size matching effect, both of which work together, and the size matching plays a crucial role at lower numbers of PO and HLB dominates at higher numbers of PO.

2023, 43 (3): 47-51. DOI: 10.12422/j.issn.1672-6952.2023.03.008
 
The Process of C 9 Petroleum Resins Production
YAN Hui,LIU Shu-xin, MENG Qiu,CONG Yu-feng,HUANG Wei
Abstract571)      PDF (203KB)(1192)      
C 9 petroleum resins was obtained by two-step synthesis from C 9 fraction, which is the side product from enthylene production in the boiling range of 140~196 ℃. The processes of free radical polymerization and catalytic polymerization by Lewis acid were well investigated, and the effect of polymerization method, reaction time and reaction temperature on product quality was discussed. The results show that C 9 petroleum resins can be obtained with light color and higher yield under the following conditions: the mass fraction of initiator 0.01%, the mass fraction of catalyst 1.50%, reaction time 4.5 h, free radical polymerization time 1.5 h, catalytic polymerization time 3.0 h and reaction temperature 55 ℃.
2011, 31 (3): 1-3. DOI: 10.3696/j.issn.1672-6952.2011.03.001
Research Progress on Lithium Extraction Technology by Electrodialysis
Yang Wang, Qiao Han, Zhanxu Yang
Abstract1242)   HTML95)    PDF (1984KB)(1185)      

This paper summarized the separation effects of different electrodialysis systems on lithium in Salt Lake, including single selective electrodialysis, ionic liquid membrane and bipolar membrane, among which ionic liquid membrane with a broad development prospect possesses the characteristics of high recognition of Li+, long?term stability under electrolysis and low energy consumption. Furthermore, the advantages, disadvantages and tendency of prospective development of different electrodialysis systems in lithium extraction from Salt Lake were analyzed, and the industrialization research on the application of electrodialysis systems for lithium extraction from Salt Lake was analyzed.

2023, 43 (1): 1-7. DOI: 10.12422/j.issn.1672-6952.2023.01.001
Preparation of Macro⁃Mesostructured Hierarchical γ⁃Al2O3 and Its Catalytic Performance for Long Chain Alkane Dehydrogenation
Qu Shengtao,Wang Yujia,Liu Dongmei,Wang Haiyan,Zhao Pengze
Abstract653)   HTML    PDF (1802KB)(1169)      
The aluminum source is made of Al2(SO4)3 solution, and the precipitant is made of NH4HCO3 solution. By modifying the aging step in the preparation process, the structure of the precursor aluminum ammonium carbonate (AACH) and the calcined γ⁃Al2O3 are modulated, and a high specific surface area nano γ⁃Al2O3 with a hierarchical pore structure was prepared. PtSnK/γ⁃Al2O3 long chain alkane dehydrogenation catalyst was prepared with macro⁃mesostructured hierarchical γ⁃Al2O3 as the carrier. C10―C13 long chain alkanes were used as raw materials to evaluate the activity and stability of the catalyst in a small fixed bed reactor. The results of the study indicated that the γ⁃Al2O3 support obtained after secondary modulation had a macro⁃mesostructured hierarchical pore structure, and the pore size distributions of mesopores and macropores were relatively concentrated. The average pore diameter, pore volume, and specific surface area were 25.40 nm, 2.09 cm3/g, and 284.5 m2/g, respectively. The initial conversion of long⁃chain alkanes dehydrogenation over PtSnK/γ⁃Al2O3 catalyst has reached 26.9% under accelerant condition and after 18 hours can still achieve 21.3%, the dehydrogenation conversion rate is higher than that of commercial alumina.
2019, 39 (4): 34-39. DOI: 10.3969/j.issn.1672-6952.2019.04.007
Research Progress of Adsorption Properties of Carbon Adsorbents for VOCs
Zhang Shaopeng, Jian Weiwei, Ma Danzhu, Liu Chao, Wang Xue
Abstract1320)   HTML    PDF (846KB)(1155)      
The adsorption properties of carbonaceous adsorbents (such as, activated carbon, biochar, CNTs and carbon⁃silica composites) for VOCs were summarized in this paper. The influence of the structure of adsorbents, the characteristics of VOCs, the humidity and the adsorption temperature were analyzed respectively. The development prospect of carbonaceous adsorbents in the future VOCs adsorption process was proposed. While continuously increasing the adsorption capacity of carbonaceous adsorbented for VOCs, improving the performance of recycling, reducing the impact of high⁃temperature and humidity environments on the adsorption capacity in industrial production was a new trend in the research and development of carbonaceous adsorbents in the future.
2021, 41 (1): 30-36. DOI: 10.3969/j.issn.1672-6952.2021.01.006
A Review of Fabric Defect Detection Methods Based on Computer Vision
Jiyang Han, Jiangtao Cao, Henan Wang, Xiaofei Ji
Abstract1243)   HTML    PDF (696KB)(1155)      

For a long time, fabric defect detection has been completed by quality inspectors. Meanwhile, the process of defect discrimination is greatly affected by subjective factors and has the problems of low detection efficiency and high cost. With the close combination of computer vision technology and various fields, fabric defect detection system based on vision has gradually become an important solution to replace manual quality inspection. For the fabric defect detection based on vision, this paper reviews the aspects including industry development, general detection standards, overall structure of the system and key technologies in detection algorithms, introduces the existing fabric defect detection products based on vision in the market, analyzes the common defect detection standards and the basic structure of the detection system, and summarizes and compares the research status of image processing and deep learning technology in the field of fabric defect detection in recent years. Finally, the paper summarizes the key problems to be solved, and discusses the possible development direction in the future.

2022, 42 (1): 70-77. DOI: 10.3969/j.issn.1672-6952.2022.01.013
Review of SOFC Anode with Resistance to Carbon Deposition
Zhang Leilei, Li Chuang, Song Zhaoyuan, Long Wen, Zhang Lei
Abstract680)      PDF (1588KB)(1154)      
Solid oxide fuel cells (SOFC) can convert the chemical energy of the fuel directly into electricity with high efficiency, low population and wide fuel applicability. Nibased ceramic material was used as the traditional SOFC anode. This anode shows carbon deposition and sulfur poisoning when natural gas was used as fuel for SOFC. Therefore, development of novel SOFC anode materials with good resistance to carbon deposition and sulfur poisoning has attracted considerable interest. This article reviews the recent developments of anode in SOFC with principal emphasis on the material aspects. In addition, the developments of carbon tolerant SOFC anode materials were presented from their properties. The emphasis will be placed on the development of perovskitetype anode material researches. Finally, this review will be concluded with its perspectives on the future research directions of this area.
2015, 35 (6): 6-11,19. DOI: 10.3696/j.issn.1672-6952.2015.06.002
Applications Development of Sulfonic Acid Calix[ n]arene
WangXiaomei,YuQihong,ChenPing
Abstract877)      PDF (3246KB)(1153)      
The synthesis of two kinds of water-soluble calixarenes-p-sulfonic acid calyx [ n] arene and p-sulfonic acid thiacalixarenes were introduced. The synthesis proposal was  mature and the post-processing was simple. The p-sulfonic acid calyx [ n] arene had good thermal stability, which provided a good basis for the subsequent application research. The application of sulfonated calixarenes in catalysis was illustrated. The strong acidic group meet the acid conditions in the catalytic reactions. In addition, compared with other types of acid catalyst, sulfonated calixarene was easy to separate from the reaction mixture and recycle and reuse, so it was a green organic catalyst; Finally, it showed good performance when it was used as the parent compound in coordination, complexation and molecular ion recognition.
 
2017, 37 (1): 1-7. DOI: 10.3969/j.issn.1672-6952.2017.01.001
Research Status of Leakage Detection Technology for Long⁃Distance Oil Pipelines
Ying Guo, Lijian Yang, Baishun Zhao, He Zhang
Abstract974)   HTML51)    PDF (1683KB)(1142)      

With the development of artificial intelligence technology and big data Internet technology, the pipeline leak detection technology is developing in the direction of intelligence. Based on the classification of continuous pipeline leak detection technology and discontinuous pipeline leak detection technology, this paper introduced the principles of various leak detection methods, summarized and analyzed the research status of long?distance oil pipeline leak detection technology at home and abroad. The application of combined oil pipeline leak detection and location technology in long?distance oil pipeline detection was prospected.

2022, 42 (4): 25-31. DOI: 10.3969/j.issn.1672-6952.2022.04.005
The Influence and Analysis of HLB on Emulsification and Viscosity of Crude Oil
Zhang Mengke,Wu Yuguo,Chang Xianyang,Lü Wenyi,Wang Tongyu,Zhang Bonan
Abstract858)   HTML    PDF (1605KB)(1105)      
Using the OP⁃10 and L61 emulsifiers to configure different hydrophilic equilibrium values (referred to as the HLB),the viscosity test of heavy oil in the second area of the oil production plant of liaohe oilfield was carried out to find out the optimal HLB of the heavy oil.At the same time, FBRM was used to measure the viscosity of heavy oil, and the effect of droplet quantity and particle size on viscous oil viscosity was analyzed.For further study on the viscosity change mechanism of heavy oil emulsion, it can be used to provide reference for the process of heavy oil reduction.Test results show that:the HLB of the emulsifying agent added to the heavy oil emulsion was 9.0,the effect of viscosity is best.At this time, the number of droplet drops to stable, compared with other HLB emulsifiers, the quantity of emulsifier is obviously low, the droplet is evenly distributed and the emulsion is stable.
2019, 39 (2): 27-32. DOI: 10.3969/j.issn.1672-6952.2019.02.005
Research Progress on Influencing Factors of Dust Removal Efficiency of Electrostatic Precipitator
Jian Wang, Jingshang Yu, Junfeng Mi, Shengnan Du
Abstract1347)   HTML    PDF (973KB)(1102)      

The dust removal characteristics and working mechanism of the current four major types of dust collectors were reviewed. It mainly focused on electrostatic precipitator technology, introduced its research status at home and abroad in recent years, analyzed the influence of many different factors (equipment structure parameters, gas characteristics, dust properties) on the efficiency of electrostatic precipitator equipment, and summarized electrostatic precipitator. The current technical shortcomings of the collector: The selection of the discharge electrode, the optimization of the best parameters, the anti?corrosion and cleaning of the dust collecting plate. In the future, the following issues should be focued on: development of discharge electrode materials suitable for new forms of electrostatic precipitators, discharge characteristics and dust removal efficiency in complex atmospheres, reduced insulation performance at the dust collector, and corrosion protection.

2021, 41 (6): 36-41. DOI: 10.3969/j.issn.1672-6952.2021.06.007
Research on the Evaluation of Supply Chain Resilience in Petrochemical Enterprises under the Dual Circulation: Based on AHP⁃BP Method
Lizhou ZHAO, Ningfeng ZHANG
Abstract1499)   HTML29)    PDF (1193KB)(1094)      

With the improvement of environmental uncertainty, the demand for supply chain stability of petrochemical enterprises in China is rising day by day. The evaluation of supply chain resilience of petrochemical enterprises has become an important means to judge the risk coping ability of petrochemical enterprises. This paper constructs a supply chain resilience evaluation index system in the petrochemical enterprises. And fuzzy analytic hierarchy process and BP neural network are used to evaluate the toughness strength of petrochemical enterprise supply chain, so as to determine the toughness level of petrochemical enterprise supply chain.It is found that the strength of supply chain toughness of petrochemical enterprises is uneven, and the overall level of supply chain resilience is low. On the basis of the research results, some practical suggestions are put forward for the forging of resilient supply chain in petrochemical enterprises.

2024, 44 (1): 89-96. DOI: 10.12422/j.issn.1672-6952.2024.01.013
Research Progress and Application of Hydrogen Purification by Pressure Swing Adsorption
Shuo ZHANG, Qiang SONG, Yulong ZHANG, Jiali ZHANG, Qi SUN
Abstract835)   HTML51)    PDF (609KB)(1087)      

As a new type of clean, carbon?free, sustainable and efficient energy source, hydrogen has great potential in the future energy mix. Hydrogen purification by pressure swing adsorption is the main separation technology for hydrogen production with high purity, low energy consumption and high degree of automation. In this paper the progress in research and application of pressure swing adsorption hydrogen production in theoretical simulation, process control optimization and adsorbent materials were critically reviewed, and the future development of pressure swing adsorption hydrogen production technology was prospected.

2023, 43 (6): 30-36. DOI: 10.12422/j.issn.1672-6952.2023.06.005
Study on the Transient Flow Law of Shutdown and Restart of Oil and Gas Mixed Pipelines with Multiple Fluctuations and Large Height Differences
Jianing Li, Shengnan Du, Kaifeng Fan, Kai Chao, Xuesong Huang, Wei Li, Weiqiang Wang
Abstract603)   HTML    PDF (2023KB)(1082)      

The geometric model of a certain oil and gas mixed transportation pipeline was established with OLGA software, and the transient flow law during the pipeline shutdown and restart process was studied. First, the distribution characteristics of temperature, pressure and liquid holdup along the pipeline during steady state operation were analyzed, and the location of the minimum temperature and the location of the maximum pressure along the pipeline were determined. The influence of environmental temperature and shutdown time on operating parameters were analyzed. The safe shutdown time when the minimum temperature temperature is higher than its freezing point was determined. In the actual operation process, the shutdown time should not exceed the safe shutdown time, otherwise problems such as pipeline condensation and excessive starting pressure will easily occur, which threaten the safety of the pipeline.

2022, 42 (2): 55-60. DOI: 10.3969/j.issn.1672-6952.2022.02.009
 
Probabilistic Computation Method for Some Types of Integral
YU Jing-xian, LI Jin-qiu, MIAO Chen
Abstract626)      PDF (936KB)(1081)      
 
Considering the complexity and infeasibility of Newton-Leibniz formula in computing some types of integral, it was used the density functions and numerical characteristics of exponential distribution, normal distribution and chi-square distribution to compute three types of integral in calculus. Three computational formulas were got. Through the process of proof, it was found that the convenience of probabilistic method and close relationship between probability theory and calculus.
2012, 32 (4): 95-98. DOI: 10.3696/j.issn.1672-6952.2012.04.025
Research Progress of Ln⁃MOF as Proton Conducting Material
Honglu Li, Liangliang Huang
Abstract782)   HTML25)    PDF (1489KB)(1074)      

Proton conductive materials are an important part of sensors and fuel cells. In recent years, the research of crystalline proton conducting materials has mainly focused on metal organic framework material(MOF). Lanthanide metal organic framework (Ln?MOF) is an important member of the MOF family, and it is easy to form a stable and diverse framework owing to the strong coordination ability, Lewis acidity and complex functionality of lanthanide ions. At present, people are beginning to focus on its research in the field of proton conduction. This article reviews the research progress in proton conduction of Ln?MOF materials with different functional acid groups (carboxylate, phosphonate or sulfonate groups, etc.) introduced into the main frame. The challenges faced by Ln?MOF materials in the study of proton conduction were prospected.

2023, 43 (2): 35-41. DOI: 10.12422/j.issn.1672-6952.2023.02.006
Event⁃Triggered and Deception Attack⁃Based Load Frequency Control for Power Systems
Bowei Ji, Xiao Zhang, Shen Yan, Zhou Gu
Abstract439)   HTML2147483647)    PDF (1424KB)(1063)      

With the increasing complexity of networked power systems, traditional control schemes are difficult to meet the actual needs. Bandwidth constraints, network security and actuator saturation have become important factors affecting the stability of power systems. An improved event trigger mechanism was introduced to improve the utilization rate of bandwidth resources for the problem of bandwidth resource limitation, and a new mathematical model of power system under deception attack and actuator saturation was constructed. Based on this number model, the sufficient conditions for the asymptotic stability of the power system were obtained by Lyapunov theory, and the design scheme of the security controller was given by using linear matrix inequality technique. Finally, an example of power system was given to illustrate the effectiveness of the proposed scheme.

2022, 42 (4): 87-96. DOI: 10.3969/j.issn.1672-6952.2022.04.014
Apply on Oil -Air Lubrication System of the Machine Pump Cluster in Petrochemical Device
SUN Chun -yi, QIU Di -fan
Abstract445)      PDF (205KB)(1057)      
    Along with developing continuously of the lubrication technology , appeared the oil -air lubrication to a technique ,the characteristics and work principle and system constitute of the oil - air lubrication were introduced.The key that the machine pump cluster of petrochemical equipment applied the oil-air lubrication was elaborated.The process of the lubricate calculation and the lubricate film calculation of oil-air two interblend fluid was discussed .With Y type oil pump lubrication of atmospheric -vacuum distillation device for example , the function of oil-air lubrication was explained .The result shows that this kind of technique has wide applied foreground in the petroleum chemical engineering profession .
2008, 28 (1): 28-30.
Resistance Measurement With Vol tage Compensation
FU Shi - min
Abstract824)      PDF (191KB)(1055)      
   While measuring central value resistance with traditional voltammetry , either the internal connecting method or external connecting method of an ammeter brings system errors of measurement results. A new method of measuring resistance with the voltage compensation voltammetry principle was described. A formula of relative standard uncertainty was given,which measured resistance with internal connecting method , external method, and voltage compensation voltammetry . With comparing the uncertainty , the measurement data were processed. The measurement results of resistance , uncertainty and computing results of errors were provided.
2007, 27 (1): 90-92.
Synthesis and Properties of Silver Nanowires with Large Diameter and High Aspect Ratio
Congying Yang, Yufang Song, Canyi Yu, Shuai Yang, Weifeng Zhong, Hongji Zhang
Abstract737)   HTML    PDF (2113KB)(1053)      

An improved ethylene glycol method was used to efficiently synthesize silver nanowires with a diameter of about 130 nm, a length of about 150 μm, and L/D was about 1 150 by adjusting the content of chloride ions, the amount of polyvinylpyrrolidone (PVP) and the reaction temperature. All raw materials are put in one time before the reaction, no need to use syringe pumps and other equipment to strictly control the content of components. The synthesized silver nanowires have high purity and few impurities. At the same time, it was purified by filtration and washed twice to obtain extremely pure silver nanowires, which is suitable for large?scale production. The conductive network of silver nanowires was constructed on the quartz glass substrate by spin coating. The results show that the light transmittance at 550 nm is 95.5%, the sheet resistance is 52.0 Ω/sq, and it have excellent photoelectric properties.

2022, 42 (2): 1-7. DOI: 10.3969/j.issn.1672-6952.2022.02.001
An Empirical Analysis of Financial Leverage and Profitability in Automobile Manufacturing Industry
Xingyu Zhou, Liangliang Han
Abstract1100)   HTML    PDF (490KB)(1021)      

In recent years, the sales volume of the automobile industry, which is the backbone of the national economy, has been declining, and the financial leverage ratio has continued to rise. In order to improve the profitability of automobile manufacturing enterprises, this paper used SPSS 26.0 and Excel 2010, collected the financial data of 145 auto A?share listed companies in Shanghai and Shenzhen from 2017 to 2019 as samples to conduct an empirical analysis and test of the relationship between corporate leverage ratio, corporate growth ability and profitability. The results show that there is a negative correlation between leverage ratio and profitability, positive correlation between corporate growth ability and profitability, negative correlation between corporate leverage ratio and growth ability, and there is a certain intermediary effect in the influence of corporate growth ability on profitability.

2022, 42 (2): 91-96. DOI: 10.3969/j.issn.1672-6952.2022.02.015
Preparation of Bimetallic MOF⁃74(Mg x Ni 1- x ) and Its Adsorption and Separation Performance for CO 2/N 2
Ping Yang, Youxi Li, Wufeng Cai, Wenbo Liang, Linhai Duan
Abstract894)   HTML50)    PDF (1354KB)(1019)      

HP?MOF?74(Mg x Ni1-x ) (x=0.25, 0.50, 0.75) was synthesized by solvothermal method with Mg and Ni as central metals and sodium dodecylbenzene sulfonate (SDBS) as template. Using flue gas CO2 and N2 as adsorbents, the performance of HP?MOF?74(Mg x Ni1-x ) in adsorption and separation of CO2/N2 at 273 K and 298 K was investigated, the isotherms of CO2 and N2 on three different HP?MOF?74(Mg x Ni1-x ) materials were measured at 273 K and 298 K by static volumetric method, and the experimental data sets were fitted by Dual Site Langmuir Freundlich (DSLF) and Single Site Langmuir Freundlich (SSLF) models. The adsorption selectivity of CO2/N2 binary mixture was estimated according to the Ideal Adsorption Solution Theory (IAST). In addition, the isosteric heat of adsorption (Qst) was calculated using the Clausius Clapeyron equation. The results show that the CO2 adsorption capacity of HP?MOF?74(Mg0.50Ni0.50) sample is 4.864 mmol/g at 273 K and 100 kPa; the adsorption isotherms of CO2 and N2 on HP?MOF?74(Mg x Ni1-x ) are in good agreement with Dual Site Langmuir Freundlich (DSLF) and Single Site Langmuir Freundlich (SSLF) models respectively, indicating that the adsorption behavior of CO2 is double sites adsorption, while the adsorption behavior of N2 is single site adsorption; at 273 K and 100 kPa, the IAST adsorption selectivity of HP?MOF?74(Mg0.25Ni0.75) for CO2 is 2 263, and the adsorption capacity and selectivity are better than those of traditional adsorbent MOF?74; the CO2 isosteric heat of adsorption on HP?MOF?74(Mg x Ni1-x ) is higher than that of N2, indicating that the surface free binding energy of CO2 on HP?MOF?74(Mg x Ni1-x ) is higher.

2022, 42 (6): 1-7. DOI: 10.3969/j.issn.1672-6952.2022.06.001
Review of Copper⁃Based Catalysts for Electrocatalytic Reduction of Carbon Dioxide
Guohua Diao, Liwei Pan, Lin Fan, Xinyu Han, Hexiang Zhong
Abstract3640)   HTML    PDF (855KB)(999)      

With the rapid economic development, the demand for energy continues to increase, and the emission of CO2 gas keep growing. The electrochemical reduction of carbon dioxide (ERC) to fuel and chemicals is an effective way to realize the conversion and utilization of CO2 as well as the storage of renewable energy. Cu?based catalysts are one of the materials which can directly reduce CO2 to high value?added chemicals(such as hydrocarbons) with high efficiency. Thus, the Cu?based catalysts have been one of the research focus of ERC technology research. The main research progress of Cu?based catalysts for ERC technology in recent years is reviewed. Firstly, reaction principle of ERC and the technology challenge are summarized, and then the cooperative control strategy for the structure and composition of copper?based catalysts is discussed for monometallic copper?based catalysts, polymetallic copper?based catalysts, copper oxide and oxide?derived copper catalysts, and copper?organic composite catalysts. In addition, research progress and unsolved problems of Cu?based catalysts are also summarized. Finally, the future trend these catalysts is also prospected.

2021, 41 (4): 1-8. DOI: 10.3969/j.issn.1672-6952.2021.04.001
Research Progress of Membrane Separation Technology in Salt Lake Lithium Extraction
Jiajun Yu, Shuang Zhao, Xiao Feng
Abstract866)   HTML72)    PDF (461KB)(997)      

In recent years, the rapid expansion of industries such as new energy has significantly heightened the demand for lithium resources. China boasts ample lithium reserves; however, 80% of these reserves are concentrated in salt lake brine, and the high magnesium?to?lithium ratio inherent in salt lakes poses challenges for lithium extraction. To ensure a stable supply of lithium resources in our country, it is imperative to develop cost?effective and highly efficient technologies for lithium extraction from salt lakes. Recent studies have demonstrated that the combination of emerging membrane separation technology with traditional processes holds great potential for achieving significant advancements in lithium extraction from salt lakes. This review aims to present the latest membrane technologies for extracting lithium from salt lake brine. It comprehensively discusses cutting?edge research findings from various perspectives, including the pore structure of membrane, precise design of the chemical environment within the pores, development of innovative membrane fabrication processes, and the integration of multiple membrane processes. By doing so, the review offers valuable insights and guidance for the design of new membrane materials. Furthermore, the review provides a comprehensive overview of the current bottlenecks faced by membrane separation technology in the process of lithium extraction from salt lakes. It also explores the potential prospects of biomimetic membrane materials.

2023, 43 (4): 30-35. DOI: 10.12422/j.issn.1672-6952.2023.04.005
The Calculation of the Default Probability and the Risk Premium Based on the Credit Transfer Matrix
Jiang Fengli
Abstract502)      PDF (881KB)(997)      
Credit rating is a comprehensive evaluation of the capability and the integrity of fulfilling economic commitments for the individual, the economy and financial instrument. The main function of credit rating lies in the credit risks revealment, which plays an irreplaceable role in increasing the efficiency of financial market. It is of great significance for the security of national finance and economy to have a proper credit rating. Different levels and time of default probability will be studied in this paper, which also includes further discussion on the risk premium and associated dependencies.
2015, 35 (4): 66-69,80. DOI: 10.3696/j.issn.1672-6952.2015.04.015
Microwave -Induced n -Hexane A romatizat ion Reaction
WANG Chan, ZHAO Zeng -hua, ZHOU Bing -lun
Abstract518)      PDF (250KB)(995)      
    The aromatization reaction over ZnNi/H ZSM -5, by the microwave heating and conventional heating methods, had been undertaken using n -hexane as the source under the conditions of different temperatures.Compared with the condition of conventional heating , the active centers of B acid and L acid in the ZnNi/ZSM -5 were excited selectively by microwave , the strength of B acid and L acid were enhanced , which accelerated the aromatization reaction, improved the yield of BTX.It is fitting that the aromatization reacted at 450 ℃ by microwave heating the yield and selectivity of BTX is increased about 5 % and 4 % respectively , dealkylation of aromatics can be promoted also , which effects the distribution of aromatics, and results in the increase of benzene and to luene , but decrease of xylene and ethylbenzene in the products .With the increasing of reaction temperature , cracking reaction is strengthened , however , the yields of C-6 and BTX still are more than that by the conventional heating .
2007, 27 (2): 24-26.
Numerical Analysis of the GasSolid TwoPhase Based on FLUENT
Gao Dezhen, Li Jialu, Li Dechen, Liu Shu, Wang Xiaoning
Abstract784)      PDF (2420KB)(981)      
The pneumatic transmit experiments with the size of sand of 1.2 mm were carried out with compressed air as pumped in the T pipeline experimental bench. Numerical simulation analysis is carried out of the pneumatic transmit process under different condition of the transmission flow and pressure, whereas the change of pressure drop and gassolid two phase volume fraction in branch pipe was achieved. Numerical simulation results show that, pressure drop is proportional to the transmission flow and pressure in the lower part of the pipe, whereas particle volume fraction is inversely proportional to the transmission flow but proportional to transmission pressure. Gas volume fraction is proportional to flow, but it is inversely proportional to pressure. The simulation results are in good accordance with the experiment results. The study provides relevant basis for the further research of the pneumatic conveying.
2015, 35 (4): 5-8,15. DOI: 10.3696/j.issn.1672-6952.2015.04.002
Novel Synthesis of Furoin
ZHU Dan, ZHANG Ying
Abstract704)      PDF (482KB)(978)      
Using furfural as raw material and VB1 as catalyst preparation of furoin was studied through benzoin condensation in the alkaline condition, pH of 9 to 10. The effect of reaction temperature, reaction time and the amount of VB1 were investigated. The optimum reaction conditions are as follows: reaction temperature: 65 ℃, reaction time: 2 h, the amount of VB1 : 8.0 g. The yield of the product reached 82.7%. The product is white needle-like crystals with the melting point of 138 ~ 139 ℃. Structure of objective product was characterized on IR and elementary analyses.
2009, 29 (2): 28-30.
Research Status of C 4 Olefin Oligomerization and Catalysts
Li Danyang, Liu Shu Wang Xiaoning, Meng Fanli
Abstract882)      PDF (1250KB)(969)      
The research status of C 4olefin polymerization at home and abroad is briefly described, and the chemical utilization ways of C 4 olefins are summarized combining with the progress of relevant technology. Isobutylene was used as an example to introduce the chemical reaction mechanism of the oligomerization; the catalytic properties and research situation of solid phosphoric acid catalyst, zeolite catalyst are emphatically described. According to the present situation of the utilization of low carbon olefins in China, the development prospects and suggestions of C 4 are put forward.
2016, 36 (5): 1-5. DOI: 10.3969/j.issn.1672-6952.2016.05.001
Abstract690)      PDF (5767KB)(957)      
2013, 33 (1): 48-52.
Progress in Research of the Synthesis Methods of Nanometer Ceria
LiuYujuan,XuJi,TongYufei,et al
Abstract1579)      PDF (1032KB)(956)      
Cerium oxide is a kind of rare earth oxides of extensive uses. It has a wide range of applications in ultraviolet absorption, luminescent materials, catalysts and so on. Nano cerium oxide has special properties and can be widely used in various fields. This paper combined the research of preparation of cerium oxide based on domestic and international literature including hydrothermal, precipitation, solgel, microemulsion, microwave and so on, and summarized the advantages and disadvantages of various preparation methods.
2017, 37 (5): 8-12. DOI: 10.3969/j.issn.1672-6952.2017.05.002
Method and Practical Analysis of Oil and Gas Long Distance Pipeline Leak Detection
Tong Chang,Wang Weiqiang,Chen Boyu
Abstract1164)      PDF (1101KB)(954)      
With the rapid development of national economy in our country, the demand of oil and gas, as a representative of the major energy, continued to increase, and the security risks of long distance oil and gas pipelines also caused people's attention. Especially, the pipeline leakage deflagration happened from time to time in recent years, which caused not only great economic losses of the people's lives and property, also caused the ecological environment pollution and destruction. Therefore the leak detection of intelligent and efficient positioning method was applied to oil and it was critical for gas pipelines in a timely manner to prevent secondary disasters. The main cause of pipeline leak was analyzed, several kinds of leak detection methods used on the pipeline at present were summarized, and the method of negative pressure wave and flow balance method was dopt in crude oil pipeline leak detection experiments. The experimental results showed that the method could monitor oil pipeline leak in real time, especially small slow leakage, meanwhile could accurately locate the leak point.
2018, 38 (03): 57-61. DOI: 10.3969/j.issn.1672-6952.2018.03.011
Finite Element Analysis of Influence of Nut Washer on Stress Distribution of Bolt Flange Joint
Songyu Yang, Yili Duo, Tie Sun, Chengbin Wang
Abstract561)   HTML    PDF (2114KB)(952)      

The finite element model of the bolt flange washer was established, and the fastening experiment of the DN500 bolt flange connection system was carried out to verify the rationality of the finite element model. By controlling the width of the nut washer and the medium pressure of the pipeline, the effect of adding the nut washer on the stress distribution on the washer and bolt was compared and analyzed. It was found that adding a reasonable sized nut washer can not only increase the contact area between the nut and the flange surface and increase the compressive stress on the gasket, but also in the case of high bolt pre?tightening load and medium pressure. Prevent the bending deformation of the bolts and the pressure failure of the washers, increase the service life of the bolts, and improve the overall sealing performance of the bolt flange connection system.

2022, 42 (3): 62-67. DOI: 10.3969/j.issn.1672-6952.2022.03.011