Ion Exchange Property of H2O2⁃Modified H1.07Ti1.73O4•H2O Layered Titanate
Zhang Jin, Zhou Wenli, Wang Xing, Kong Xingang
2020, 40 (3): 1-7. DOI:10.3969/j.issn.1672-6952.2020.03.001
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In this paper, layered titanic acid H1.07Ti1.73O4•H2O (HTO) was treated with hydrogen peroxide solution to achieve the hydrogen peroxide intercalation and modification of HTO. The hydrogen peroxide molecules entered into the interlayer of TiO6 octahedral layer, forming a peroxytitanium coordination bond with Ti4+ in the layer, which increased the negative charge density of the TiO6 layers. XRD, SEM, TEM, XRF, FT⁃IR and other methods were used to characterize the samples before and after ion exchange. The ion exchange experiments show that compared with HTO, the ion exchange efficiency and ion exchange capacity of H2O2⁃modified HTO are greatly enhanced. And the main reason is that the introduction of H2O2 leads to the increase of negative charge of TiO6 octahedral layers.
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Distribution Characteristics and Pollution Assessment of Heavy Metals in Urban Street Dust of Benxi City
Wang Xiaowen, Li Fayun
2020, 40 (3): 8-13. DOI:10.3969/j.issn.1672-6952.2020.03.002
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X⁃ray fluorescence spectroscopy was used to explore the spatial distribution characteristics and potential ecological risks of heavy metals (Cu, Pb, V, Zn, Cr, Mn) in street dust in different functional areas of the city.The heavy metal content in the dust samples of the cultural and educational districts, commercial districts, residential areas, industrial areas, traffic areas and mixed areas in Benxi City was analyzed,and the results show that the average contents of heavy metals in street dust samples are 3.4, 3.1, 0.9, 5.5, 2.0 and 1.0 times of the Benxi Soil Element Background Values, respectively. The spatial distribution of heavy metal elements was that Cu, V and Cr were highest in the cultural and educational districts, Pb, Zn and Mn were highest in the industrial districts, Cu, Pb and Zn were lowest in the mixed districts, Cr and Mn were lowest in the commercial districts, and V was lowest in the residential districts. The environment risk of heavy metal pollution in street dust of Benxi city was assessed by Potential Ecologically Risk Index .The assessment results show that V, Cr and Mn are low potential ecological hazards, Zn is a medium potential ecological hazard, Cu and Pb have reached heavy potential ecological hazards.
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Desulfurization of Petroleum Coke by Chemical Oxidation
Huang Huiyang, Cao Zubin, Han Dongyun, Liang Feixue, Zhu Tao, Zhu Yao
2020, 40 (3): 14-17. DOI:10.3969/j.issn.1672-6952.2020.03.003
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The desulfurization law of high sulfur petroleum coke was studied by chemical oxidation method. In this paper, hydrogen peroxide was used as oxidant, formic acid, acetic acid and propionic acid were used as catalysts. The influences of petroleum coke particle size, the ratio of oxidant volume and petroleum coke mass (liquid⁃solid ratio), reaction time and reaction temperature on the desulfurization effect were investigated. The experimental results show that the desulfurization effect of hydrogen peroxide⁃formic acid oxidation system is the best, which is better than the other two oxidation systems. The petroleum coke particle size is 100 mesh, the liquid⁃solid ratio is 20 mL/g, the oxidation reaction time is 18 hours, and the reaction temperature is 60 ℃ for oxidation. Under the optimum conditions of the desulfurization experiment, the sulfur content of petroleum coke decreased from 3.32% to 2.65%, and the desulfurization rate reached 20.2%.
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Palladium⁃Catalyzed meta⁃Alkenylation of m⁃Methylphenylacetic Acid and Ibuprofen
Jiao Bo, Du Haiwu, Dai Zhenhua, Wang Jingyun
2020, 40 (3): 18-23. DOI:10.3969/j.issn.1672-6952.2020.03.004
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The direct meta⁃C-H functionalization has proved to be more challenging due to the high energy transition state of marcrocyclic metallacycles which makes its formation extremely difficult. In this paper, the reaction of allyl acetic acid alkenylation based on pyrimidine template under palladium catalysis was studied. The reaction conditions were optimized, the influences of solvent effect, catalyst and oxidant type on the reaction were investigated, and the optimal reaction conditions were obtained. The experimental results show that the designed pyrimidine⁃directed aryl acetic acid C-H bond activation reaction can realize the meta⁃selective functionalization reaction of aryl acetic acid derivatives. A meta⁃alkenylation ibuprofen derivatives with potential drug activity can be constructedby using this strategy.
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Application of Wittig Reaction in Synthesis of α,β⁃Unsaturated Carboxylic Esters
Zhao Shichen, Ma Jinbo, Yu Fang
2020, 40 (3): 24-27. DOI:10.3969/j.issn.1672-6952.2020.03.005
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In this paper, methyl bromoacetate and triphenylphosphine were used as starting materials. First, bromophosphorus salt was prepared, and then alkali was added to prepare Wittig reagent. Preparation of α,β⁃unsaturated carboxylic acid ester (methyl cinnamate) by Wittig reaction using benzaldehyde and Wittig reagent The results show that the optimal conditions for the reaction are: Wittig reagent and benzaldehyde are used as raw materials, benzene is used as a solvent, and potassium carbonate is added as an additive. The reaction is stirred at room temperature for 24 hours, and the final product methyl cinnamate is obtained in a higher yield (86%). At the same time, the configuration of the product is a trans olefin product, indicating that the method has good stereoselectivity.
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Study on the Deposition of Pipeline System Protection in Nuclear Power Plants
Zhao Yanpeng, Wu Zhifeng, Jin Shuo, Wang Hao, Zhang Chuanxin, Wang Fuqiang
2020, 40 (3): 28-34. DOI:10.3969/j.issn.1672-6952.2020.03.006
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In order to study the phenomenon that the particles contained in the two⁃phase flow in the nuclear power plant are deposited in the pipeline under high temperature and high pressure, the mechanism of particle erosion on the pipeline is deeply explored. The similar principle and approximate modeling method are used to design and build a nuclear power pipeline. The experimental platform for the key parameters of the actual operation of the system.The results of the 30 h elbow deposition experiment show that the outer wall and inner wall of the 90° horizontal elbow are the sedimentary hot area, the outer wall axial angle of 30～45 degrees is the maximum sedimentary area, the maximum deposition of Co elements is 1.98×10－10 g on 8 mm×8 mm×3 mm sample. The results of this paper can provide data basis for radiation dose prediction and radiation protection of nuclear power plants.
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C4 Olefins Generation Rules on Pd⁃Ag Catalyst for Acetylene Selective Hydrogenation
Gong Xun, Lü Manli, Qin Yucai, Song Lijuan
2020, 40 (3): 35-39. DOI:10.3969/j.issn.1672-6952.2020.03.007
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In this paper, the key problems of catalyst deactivation caused by the formation of green oil on the surface of acetylene selective hydrogenation Pd⁃Ag catalyst were investigated. XRD and H2⁃TPR were used to characterize the composition and the structure of catalyst. The selective hydrogenation performance of Pd⁃Ag catalyst for acetylene and the formation of green oil precursor C4 olefins during the reaction were investigated by using a 10 ml fixed bed high pressure hydrogenation unit. The results show that there are significant differences in the acetylene hydrogenation activity of Pd⁃Ag/Al2O3 catalysts in several different preparation processes, which mainly depend on the dispersion of Pd on the catalyst surface. The close mixing between the promoter Ag and the active center Pd can enhance the electrons and geometric effect, more Pd⁃Ag alloy phase is generated, which reduces the hydrogenation activity of the catalyst, but increases the stability of the catalyst; while the amount of C4 olefins is positively correlated with the activity of the catalyst. The higher the catalyst activity, the more C4 olefins are generated. The conclusion of this study reveals the deactivation mechanism of Pd⁃Ag catalyst, which has important guiding value for catalyst modification and process condition optimization.
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Research on Geologic Characterization and 3D Geological Modeling for Low Permeability Reservoir
Luo Tingting, Yao Zhenjie, Duan Jingjie, Li Jian, Zhao Yongpan
2020, 40 (3): 40-44. DOI:10.3969/j.issn.1672-6952.2020.03.008
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In recent years, low permeability reservoirs have accounted for 70% of China's new oil reserves, among which the Ordos basin accounts for more than half, with considerable development potential. Therefore, the efficient development of low permeability reservoir is urgent.. In order to fully understand the properties of reservoir before development, using core observation, rock thin section and other test data, this paper focused on the research of reservoir petrology characteristics, reservoir sedimentary microfacies and sand body distribution, reservoir physical characteristics and heterogeneity of Chang 4+522 formation in Wuqi oilfield in Ordos basin. Then, based on these research results, 3D geological model of reservoir was established. The results show that Chang 4+522 formation has the rock type of fine⁃grained feldspar sandstone; mainly develops subaqueous distributary channel sedimentary microfacies and large thickness, wide distributed and good continuity sand body; belongs to low porosity, low permeability heterogeneous reservoir. On the basis of comprehensive geological studies, the structural model, phase model, porosity and permeability model of Chang 4+522 reservoir in Wuqi oilfield established are accurate and reliable. Studies on reservoir physical characteristics plays a good constraint role in the modeling process. The established 3D static model of the reservoir will serve as the foundation for dynamic flow simulation in the next step. The research approach can also provide reference for the preliminary research of the similar project.
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Simulation and Prediction of Particle Property on Erosion Wear of Special⁃Shaped Pipe Fittings of Gas Transmission Pipeline
Xu Xin, Wu Yuguo, Sun Yan
2020, 40 (3): 45-51. DOI:10.3969/j.issn.1672-6952.2020.03.009
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In the gas pipeline, the gas⁃solid two⁃phase flow causes erosion and wear on the inner wall of the pipeline, and the erosion wear in the tapered tube is particularly serious. Using the knowledge of computational fluid dynamics, the model was established by CFD simulation software, the fluid⁃solid two⁃way coupling equation was used, and standard k⁃ε model and discrete⁃phase model (DPM) were used for analysis. Investigating the influence of inlet flow velocity, solid particle size and particle mass flow rate on the wear and tear of reducing pipe, and predicting the location of the tapered tube where erosion wear is likely to occur and the optimum flow rate of natural gas. The results show that the inlet flow rate increased from 5 m/s to 25 m/s, the maximum erosion rate of the tapered tube increased first, then decreased and then increased. When the inlet flow rate is 15 m/s, the erosion rate reached the minimum, which is 1.76×10-6 kg/（m2•s）. The particle size increases from 0.5 mm to 4.5 mm, and the maximum erosion rate increases from 4.23×10-6 kg/（m2•s）to 7.56×10-6 kg/（m2•s）, and then gradually decreases to 2.68×10-6 kg/（m2•s）. The particle mass flow rate increases from 0.1 kg/s to 0.6 kg/s, when the inlet flow rate is 15 m/s, the maximum erosion rate increases from 1.76×10-6 kg/（m2•s） to 1.00×10-5 kg/（m2•s）. The erosion wear area is mainly located on the lower wall surface of the tapered tube throat, the lower wall of the tapered tube segment from the 2D region of the throat and the upper wall of the tapered tube segment outside the 2D region, and the erosion wear area of the upper wall surface is approximated by "U" type symmetrical distribution. During gas transfer, the optimum inlet flow rate of gas through the reducing pipeline should be 15 m/s. In order to prevent erosion and wear, it should also be noted that the particle size should not be too small, and the mass flow rate should be controlled within a reasonable range.
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Water Injection Optimization Technology in High Water Cut Period of Ultra⁃Low Permeability Reservoir in Fengfuchuan Oilfield
Ai Xiaofan, Zhang Jinghao, Chen Jing
2020, 40 (3): 52-56. DOI:10.3969/j.issn.1672-6952.2020.03.010
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Fengfuchuan Oilfield is a ultra⁃low permeability reservoir, pilot experiment of pre⁃water injection in Chang 2 reservoir began in 2002. In 2003, the development of water injection in the whole area was basically realized. However, the development effect of the whole area was not ideal. The comprehensive water content increased from 25.0% in the initial period to 92.0% in 2015, and entered the stage of ultra⁃high water cut period.The main problems faced in this area are that the phenomenon of fractured water flooding and water channeling is more serious, the water content of the oil well rises obviously, the output of a single well is low, and the output of the oil field decreases rapidly. In this paper, the geological of the whole area was recognized again. On the basis of fine comparison of single sand bodies, improvement of injection⁃production well nets and improvement of the corresponding degree of small⁃layers, the first one was to propose a large⁃area water injection on the whole area, a partial slow and gentle water injection to supplement the stratigraphic energy; the second one was to adopt two sets of injection⁃production patterns to realize stratified injection, expanded the original well spacing, and solved the inter⁃layer contradiction; the third one was to improve the single well production efficiency and improved the single well production to improve the development of the whole area.
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Research on Damping Coating of Steam Turbine Blade Damping Coating
Zhang Xiuming, Chen Shengjun, Deng Zilong, Jiang Wenquan, Yang Fan, Du Guangyu
2020, 40 (3): 57-62. DOI:10.3969/j.issn.1672-6952.2020.03.011
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　The damping vibration performance of the blade after metallization of steam turbine blades is studied. The turbine impeller was simplified and then modeled by ug software, and the modal analysis is carried out on the integral blade disk of the same thickness of the aluminum, titanium, aluminum titanium film blade and the uncoated blade by ANSYS software. The vibration pattern and natural vibration frequency are obtained, and the vulnerable parts of the impeller are observed as a whole；Harmonic response analysis of a single blade,The deformation of the four blades under the same load was further analyzed, and their damping effects were discussed.Combined with the experimental results, the test specimens were subjected to aluminum plating, titanium plating, aluminum plating first and then titanium plating treatment, and uncoated specimens formed a control group.Testing the damping performance of coatings with a Dynamic Mechanical Thermal Analyzer (DMA).The results show that the deformation of each step mode of the blade after coating is smaller than that of the blade without coating，it can play a certain damping effect on the blade coating.
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Design and Development of Energy Efficiency Evaluation System for Centrifugal Pump Unit Based on .NET Platform
Sun Chao, Hao Jiao, Sun Tie, Zhang Suxiang, Ma Chao
2020, 40 (3): 63-69. DOI:10.3969/j.issn.1672-6952.2020.03.012
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At present,the energy efficiency evaluation of centrifugal pump units in China is still in the exploratory stage.In order to evaluate the energy efficiency level of the equipment quickly and accurately,based on the MVC model of the .NET platform,this paper designs and develops an automated evaluation system. On the basis of establishing the mathematical model of energy efficiency evaluation of pump units,the parameters are collected and processed. The data is imported manually or by accessing the database，and the energy efficiency calculation is performed according to the standard using a simple and highly accurate formula. The system is applied to verify the example，and the operating condition of the equipment is compared with the economic operation discriminate table to judge the operation of the unit. The results show that the evaluation results calculated by the software are accurate.Without complicated manual calculation,the evaluation time can be shortened,the work efficiency can be improved，and it has certain application value for industrial production.
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Creep Life Prediction of GH4169 Based on the Modified θ Projection Method
Zhang Shuang, Liu Feng, Li Ronghua, Zhang Guoming
2020, 40 (3): 69-73. DOI:10.3969/j.issn.1672-6952.2020.03.013
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Based on modified θ projection method, creep experiments were carried out on GH4169 superalloy under different temperature and stress conditions,the creep data under different parameters were obtained and corresponding creep curves were drawn.The modified θ projection method was used to perform nonlinear fitting of the obtained experimental curve,and creep equations related to temperature and stress were established.The creep life curve of GH4169 superalloy is verified by the creep equations,and the results are in good agreement,so as to reach the effect of creep life prediction.
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Research on Open⁃Circuit Fault Detection and Fault⁃Tolerant Control of Three⁃Phase Three⁃Level PV Inverters
Pan Bin, Wang Youzheng, Chen Mingming, Zhao Yong, Yu Jingxian
2020, 40 (3): 74-82. DOI:10.3969/j.issn.1672-6952.2020.03.014
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In order to improve the operation reliability of the three⁃level PV inverter, an open⁃circuit fault detection and a voltage space vector redundancy fault⁃tolerant control method based on the improved current flow path were proposed. First, based on the three⁃phase three⁃level PV topology structure, the circuit current flow path after the open⁃circuit fault of each partial power device was analyzed in detail, the fault detection could be carried out by the current size flowing through the clamping diode and the load, the switching state of the switching device, and the fault type could be classified by injecting the under⁃excitation reactive current in a short time. Then, the change of the voltage space vector of the inverter after the open⁃circuit fault of the power device in different positions was theoretically explored. And the fault⁃tolerant control was completed according to the distribution law of the voltage space vector after the inverter fault and the redundancy vector of the inverter. The proposed method was fast in fault detection and fault⁃tolerant control without additional hardware cost and complex calculation. Finally, a prototype with rated power of 10 kW was built to verify the effectiveness and reliability of the proposed method.
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Vehicle Detection System Based on Adversarial Learning and Depth Estimation
Xu Yuan, Zhai Chunyan, Wang Guoliang
2020, 40 (3): 83-90. DOI:10.3969/j.issn.1672-6952.2020.03.015
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With the continuous development of target detection technology,the vehicle detection system for road scenes has been widely used in the field of automatic driving. Compared with the traditional target detector, though the target of vehicle detection is relatively simple, two major problems need to be solved. First, the characteristics which provided to the detector are usually incomplete in some complex road scenes, and other problems such as occlusion and deformation will occur. Second, it is necessary to estimate the distance of different vehicles to ensure the car can make timely evasive action in the process of automatic driving, which means it needs depth estimation of the target area of the image. Aiming at these two problems, a vehicle detection system based on anti⁃sample generation and depth map reconstruction was proposed. A confrontation network was designed for the pre⁃training target detection network called Faster⁃RCNN, which was used to generate a large number of samples during the training process, and train the vehicle detector with these samples. According to the detection results, the vehicle distance is estimated to inform the system to make evasive action in time through the reconstruction of 3D scene and camera pose recovery depth map. The experimental results show that this detection system can improve the detection effect and estimate the distance of the target vehicle without increasing the data training sample.
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Distributed Parameter Model⁃Based Fault Location Method for Transmission Lines in Interconnected Power Systems
Liu Xiaoqin, Li Qiang, Sun Haijun, Liu Lu
2020, 40 (3): 91-98. DOI:10.3969/j.issn.1672-6952.2020.03.016
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A single terminal fault location method for overhead transmission lines in general interconnected power system with n⁃bus was proposed. High accuracy in fault location was achieved by using both an accurate distributed parameters model for the faulted transmission line, and a two⁃bus Thevenin equivalent network model for the power system that accurately accounted for its inter connectivity. The method was tested by using transient fault data obtained from MATLAB simulations of an 11⁃bus interconnected power system. The results show that the method is capable of estimating the fault distance with high accuracy for various fault conditions. And it is sensitive to errors in the value of the local bus impedance, but insensitive to errors in the value of the remote bus impedance.
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