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Review of additives for electrolyte of sodium-ion battery Yuyue GUO Xiaoying ZHAI Ningbo ZHANG The Chinese Journal of Process Engineering    2023, 23 (8): 1089-1101.   DOI: 10.12034/j.issn.1009-606X.223104 Abstract （590）   HTML （32）    PDF （3494KB）（494）       Knowledge map    Save With the upsurge of the energy revolution, secondary battery as a new way of energy storage has been widely concerned owing to their efficient energy conversion. As we all know, lithium-ion batteries (LIBs) have high operating voltage and high energy density, they can be used in various application scenarios, such as electrical vehicles (EV), portable electronic devices, and large-scale energy storage systems. However, due to the shortage of lithium resources and rising prices of raw materials, many battery companies are observed to undergo cost pressure and bankruptcy risk. Given this, sodium-ion batteries (SIBs) work similarly to lithium-ion batteries, but they have great advantages in terms of resource reserve, low cost, low temperature, rate performance, and safety, thus have received strong attention from researchers and engineers. In the sodium-ion battery system, it is also composed of the positive electrode, negative electrode, electrolyte, separator, and other key components. The electrolyte, as the intermediate bridge connecting the positive and negative electrode material system, plays a vital role to undertake the transport of sodium ions, which mainly consists of organic solvent, sodium salt, and additives. The introduction of a small number of functional additives can significantly improve the overall performance of the battery because it constructs a solid electrolyte interface (SEI) between electrolyte and electrode. Different kinds of additives can exhibit specific properties to meet different conditions. This review focuses on the use of electrolyte additives, including unsaturated carbonates, sulfur compounds, phosphorus compounds, silicon compounds, inorganic sodium salts, and other types of components. Meanwhile, the research progress and related mechanisms of this addition agent in the electrolyte of sodium-ion batteries in recent years were summarized as a reference for subsequent research. Finally, the future study of electrolyte additives prospects from the science idea and practical application, for example, density functional theory, AI for science, and in-situ analysis method for SIBs. Related Articles | Metrics

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Research progress of thermal management technology for lithium-ion batteries Jiaxin LI Pengzhao LI Miao WANG Chun CHEN Liangyu YAN Yue GAO Shengchen YANG Manman CHEN Cai ZHAO Jing MAO The Chinese Journal of Process Engineering    2023, 23 (8): 1102-1117.   DOI: 10.12034/j.issn.1009-606X.223094 Abstract （353）   HTML （21）    PDF （13593KB）（200）       Knowledge map    Save Efficient battery thermal management technology is critical to the safe operation, long cycle life, and overall cost reduction of lithium-ion batteries and is important in promoting the large-scale application of lithium-ion batteries. In this review, several mainstream battery thermal management technologies are discussed in detail, including air cooling, liquid cooling, new phase change material cooling, and thermoelectric cooling technology. The battery heat generation model is briefly described. Finally, the development direction of battery cooling technology is prospected. Air cooling technology is simple in structure, but it is difficult to ensure temperature uniformity of the cells within the battery pack and is not suitable for cooling large lithium-ion battery packs, but is more suitable for small flying electric devices and low-end electric vehicles. Cooling plate liquid cooling technology is more effective, but there is a risk of coolant leakage and the temperature uniformity needs to be further improved. Immersion liquid cooling technology offers significant cooling and temperature uniformity but is expensive and is likely to be used more often in the future in energy storage plants with high cooling requirements, while for most lithium-ion electric vehicles the lower-cost cooling plate liquid cooling technology is more suitable. Phase change material cooling and thermoelectric cooling technologies without moving parts have achieved initial commercial application in electronic equipment and small power plants, but the cooling efficiency is low and needs further refinement. It is worth noting that it is critical to choose the right cooling technology for the user's needs. While there is no perfect cooling solution, a combination of cooling technologies can be used to meet the thermal management needs of a wider range of application scenarios. Related Articles | Metrics

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Advances in biosynthesis of diamine as core monomers of new nylon materials Kun LIN Zhuang LI Kun WANG Ying BI Xiuling JI Zhigang ZHANG Yuhong HUANG The Chinese Journal of Process Engineering    2023, 23 (7): 958-971.   DOI: 10.12034/j.issn.1009-606X.223147 Abstract （322）   HTML （15）    PDF （1140KB）（256）       Knowledge map    Save In the context of carbon neutrality, bio-diamine synthesis is an effective way to achieve the low-carbon production and sustainable development. Using synthetic biology, metabolic engineering, protein engineering strategies, we are able to design and construct efficient key enzymes and pathways for the biosynthesis of diamines. In this work, the progress of diamine synthesis is reviewed around two synthetic strategies: microbial de novo fermentation and whole-cell catalysis. The main diamines include 1,4-butanediamine, 1,5-pentanediamine, and 1,6-hexamethylenediamine. The biosynthesis of butanediamine mainly includes ornithine decarboxylation and lysine decarboxylation pathways, and butanediamine is mainly produced by fermentation. However, the current yield of butanediamine is low and cannot meet the requirments of industrial production. The biosynthesis of pentanediamine depends on the decarbosylation of L-lysine, mainly by de novo fermentation and whole-cell catalysis. The whole-cell catalysis for pentanediamine is more efficient, which has been widely used in large-scale production with the maturity of the technology. Hexamethylenediamine is currently synthesized by constructing artificial pathways. In addition, to address the challenges encountered in the biosynthesis of diamines, such as many by-products, poor strain activity, low yield, difficult separation, and purification, we proposed methods to improve the biosynthesis of diamines by combining metabolic engineering and protein engineering to optimize key enzyme catalysis, exploring the mechanism of cell damage caused by diamine accumulation, enhancing the specificity and activity of enzyme catalysis to improve production intensity, and optimizing the fermentation system to simplify the subsequent separation and purification steps. Finally, we foresee the future direction and development prospect of diamine biosynthesis. Related Articles | Metrics

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Research progress in modification of layered oxide cathode materials for sodium-ion batteries Miaomiao LI Xiangyun QIU Yanxin YIN Tao ZHANG Zuoqiang DAI The Chinese Journal of Process Engineering    2023, 23 (6): 799-813.   DOI: 10.12034/j.issn.1009-606X.222296 Abstract （303）   HTML （89）    PDF （47402KB）（321）       Knowledge map    Save Sodium-ion batteries (SIBs) have been regarded as the major candidate technologies for large-scale energy storage applications due to the rich abundance of Na sources, low cost and safety. And the development of cathode materials also determines the final performances and commercialization. Layered oxide cathode materials have the advantages of high specific capacity, simple structure and good stability. It is one of the most promising sodium cathode materials at present. However, such materials are still faced with irreversible changes in the electrochemical process, unstable storage in air and poor interface stability, which seriously restricts the development of commercialization of SIBs. In order to solve these problems of materials, researchers modified and optimized them. Accordingly, the modification measures of ion doping, surface coating, nanostructure design and P/O mixing and other related modification measures of sodium electric layered oxide cathode materials, which provides a basis for the modification research of sodium electric layered oxide cathode materials are reviewed in this review. Besides, the future development trend of layered oxides is prospected. Related Articles | Metrics

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Theoretical design of new energy solid-state battery materials and development of battery technology under the background of carbon peaking and carbon neutrality Hongjie XU Guanghui WANG Yujie SU Zhigao ZHANG Haitong LI Zhongzheng YANG Yuchen WANG Linyue HU Guoqin CAO The Chinese Journal of Process Engineering    2023, 23 (7): 943-957.   DOI: 10.12034/j.issn.1009-606X.223113 Abstract （227）   HTML （7）    PDF （4779KB）（219）       Knowledge map    Save Rechargeable lithium metal batteries (LMBs) have attracted wide attention due to their high theoretical energy density and important applications in portable electronic devices, electric vehicles, and smart grids. However, the implementation of LMBs in practice still faces many challenges, such as low Coulombic efficiency, poor cycle performance, and complex interfacial reactions. An in-depth analysis of the physical basis and chemical science of solid-state batteries is of great significance for battery development. To confirm and supplement the experimental research mechanism, theoretical calculation provides strong support for exploring the thermodynamic and kinetic behavior of battery materials and their interfaces and lays a theoretical foundation for designing batteries with better comprehensive performance. In this review, the theoretical and structural design ideas of the Li10GeP2S12 system and argyrodite system in sulfide solid electrolytes are reviewed, including the transport mechanism and diffusion path of lithium ions. The theoretical design ideas of new anti-perovskite Li3OCl and double anti-perovskite Li6OSI2 electrolyte systems are analyzed. The transport mechanism of Li+ in oxide solid electrolyte systems under defect regulation is reviewed. In addition, the theoretical design of new halide electrolyte systems, and the role of computational materials science in the study of battery material properties are also introduced. The key issues such as ion transport mechanism, phase stability, voltage platform, chemical and electrochemical stability, the interface buffer layer, and electrode/electrolyte interface are analyzed by theoretical methods. Understanding the charge-discharge mechanism at the atomic scale and providing reasonable design strategies for electrode materials and electrolytes. Related Articles | Metrics

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Research progress on liquid bridge fracture in field of micro-nano technology Zhaofei ZHU Yalong CHU Xianming GAO The Chinese Journal of Process Engineering    2023, 23 (6): 814-825.   DOI: 10.12034/j.issn.1009-606X.222287 Abstract （194）   HTML （8）    PDF （4290KB）（137）       Knowledge map    Save Affected by the scale effect, the morphological characteristics of liquid bridges at the microscale determine the changes in liquid bridge forces that are area-related. Liquid bridge forces have an important impact on the formation and fracture of liquid bridges. The liquid bridge fracture mechanism based on liquid bridge morphology is the theoretical basis of biology, chemistry, materials, micro-nano technology, and many other research fields. At present, the study of liquid bridge fracture is an interdisciplinary discipline involving mathematics, fluid mechanics, interface chemistry, materials science, and other disciplines, however there is few review of the research progress focusing on liquid bridge fracture based on liquid bridge morphology. This review mainly summarizes the fracture theoretical models and experimental methods of axisymmetric liquid bridges, non-axisymmetric liquid bridges, and non-Newtonian liquid bridges. It mainly introduces the weak nonlinear behavior of the fluid generated during the tensile and rupture of the liquid bridge under equilibrium or steady state caused by the forced hydraulic bridge. The influences of key factors such as liquid volume, viscosity, surface tension, wettability, roughness of the solid surface, fracture speed, and liquid bridge morphology on the fracture location or liquid distribution rate of the liquid bridge are systematically described. The experimental methods for quantitatively studying the use of different key parameters affecting liquid bridge fracture are analyzed. The structural characteristics of different experimental apparatus and their advantages and disadvantages are compared and discussed. Furthermore, the innovative and high-value research direction of the research is summarized and proposed, which may be used in future research. Finally, the research frontier trends of liquid bridge fracture in the field of micro-nano technology prospected, and it is pointed out that the future research focused on issues including a more comprehensive hydraulic bridge fracture model, the fracture mechanism, and multi-parameter control method of the liquid bridge. Related Articles | Metrics

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Research progress of core monomer separation and purification technology for bio-based materials Kun WANG Xiuling JI Kun LIN Yuhong HUANG The Chinese Journal of Process Engineering    2023, 23 (8): 1137-1149.   DOI: 10.12034/j.issn.1009-606X.222314 Abstract （179）   HTML （8）    PDF （2738KB）（108）       Knowledge map    Save The production of petrochemical-based materials consumes large amounts of non-renewable resources and cause a certain degree of pollution to the environment. The performance of bio-based materials produced by renewable resources can be comparable to that of petrochemical based materials, which is in line with the development concept of green, low-carbon and environmental protection, and provides strong technical support for the realization of the goal of carbon peaking and carbon neutrality. In recent years, with the domestic and international policies tilted to the bio-based materials industry, bio-based materials have become a new material for domestic and international development, providing a good opportunity for the development of bio-based materials industry. The core monomer of bio-based materials produced by biological method has the advantages of mild production conditions, low price, and green environmental protection. But the complex composition within the fermentation broth as well as the low concentration of monomers and the difficulty of separation have seriously restricted the development of the whole industry of bio-based materials. The production of bio-based materials requires high-purity monomers, and a small amount of impurities affect the appearance and performance of bio-based materials. The existing research and application of separation of core monomers of bio-based materials has developed the process of obtaining high purity separation and purification of core monomers of bio-based materials by taking full advantage of chemical separation technology. This review briefly introduces the current status of the production of bio-based materials, reviews the research progress of several widely used separation and purification technologies for core monomers of bio-based materials in recent years, analyzes the advantages and disadvantages of current separation technologies. Finally providing an outlook on the development trend of separation and purification technologies for core monomers of bio-based materials. Related Articles | Metrics

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Gas-liquid flow simulation of a distillation tray based on OpenFOAM Xiaoqing ZHOU Yunpeng JIAO Tianbo FAN Xianfeng HE Jianhua CHEN The Chinese Journal of Process Engineering    2023, 23 (6): 858-869.   DOI: 10.12034/j.issn.1009-606X.222258 Abstract （164）   HTML （2）    PDF （8891KB）（144）       Knowledge map    Save Distillation column with sieve tray is an important separation equipment and widely used in the process industry. The complex behavior of the gas-liquid two-phase flow in distillation columns, especially on the tray, significantly affects the separation performance. With increasing applications of the CFD simulation in multiphase flow, it is interesting to adopt the CFD tools in distillation design and optimization. Traditionally, commercial CFD software has been applied in this field, while they face the problems of black-box feature, limited and expensive license, inflexibility of developing tailored models, etc. Therefore, this work turns to the open source platform of OpenFOAM. By using the Eulerian solver in OpenFOAM, an experimental sieve tray column is studied. The two-phase flow characteristics under different operating conditions are explored, including the height of the clear liquid layer, the gas and liquid velocity, the pressure drop, etc. The predicted trends are consistent with the experimental results. The simulated clear liquid height decreases with increasing gas flow rate and increases with liquid flow rate, and its deviation from the experiments is attributed to the empirical drag correlations which need further study. The influences of sieve holes and liquid inlet conditions on the liquid velocity distribution have been studied. It is found that the number of sieve holes has little impact, and simulations with non-uniform liquid inlet conditions agree with the experiments better. This study verifies the feasibility of using OpenFOAM to simulate distillation columns. The next step is to apply the mesoscale approach to gas-liquid crossing flow systems, construct a new interphase drag model to improve the accuracy of the simulation, and consider the influence of heat and mass transfer on the flow field. This work lays a foundation for the next-step coupling simulations, which is promising for the design and optimization of distillation columns. Related Articles | Metrics

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Research progress on desulfurization technology for blast furnace gas Xindong WANG Tingyu ZHU Yuran LI The Chinese Journal of Process Engineering    2023, 23 (7): 1003-1012.   DOI: 10.12034/j.issn.1009-606X.222334 Abstract （164）   HTML （7）    PDF （1011KB）（113）       Knowledge map    Save The desulfurization technology for blast furnace gas as a source of emission reduction technology is of great significance to promoting ultra-low emission for the whole process in the iron-steel industry. The sulfur-containing components in the blast furnace gas are mainly organic sulfur, coexisting with other complex components. This work discusses the emission limits of sulfur-containing components in various occurrence forms (SO2, H2S, and S), and analyzes their transformation relationship through the mass balance of sulfur. The bottleneck of desulfurization technology for blast furnace gas is to remove the carbonyl sulfur (COS). The aluminum-based catalyst and carbon-based catalyst used for COS catalytic hydrolysis are analyzed in detail, in which γ-Al2O3 is both a carrier and an active component, and activated carbon has the functions of catalyst and adsorbent. The effect mechanism of the complex components O2, and Cl- on the deactivation of hydrolysis catalyst is further elucidated due to the formation of deposition products. For the gaseous H2S formed after the COS hydrolysis, the two kinds of wet removal technology, mainly including the chemical absorption method and catalytic oxidation method, are compared in the reaction mechanism, desulfurizer and product. The difference among the zinc oxide, iron oxide, and activated carbon adsorbent used in the dry removal technology is also concretely elaborated in the reaction mechanism, sulfur capacity, and temperature adaptability. In view of the integrated adsorption of organic sulfur and inorganic sulfur, molecular sieve adsorbent is briefly described in the selective adsorption principle and regeneration process. The "hydrolysis+wet", "hydrolysis+dry", and integrated removal processes have been explored and applied currently, which are preliminarily evaluated. Finally, it is pointed out that the research and development of desulfurization technology focus on how to improve the activity of the hydrolysis catalyst and reduce the influence of complex components in blast furnace gas on catalyst activity and improve the applicability of the technology. Related Articles | Metrics

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Research progress of lithium polysulfide capture in lithium-sulfur batteries Tingting HU Haijian LIU Yunyi CHEN Lingli LIU Chun'ai DAI Yongsheng HAN The Chinese Journal of Process Engineering    2023, 23 (9): 1231-1243.   DOI: 10.12034/j.issn.1009-606X.222413 Abstract （162）   HTML （16）    PDF （6063KB）（164）       Knowledge map    Save Lithium-sulfur battery has an ultra-high theoretical specific capacity (1675 mAh/g) and theoretical specific energy (2600 Wh/kg), which is far higher than commercial secondary batteries. In addition, the sulfur element is rich in the earth, and its price is cheap, the extraction process is environmentally friendly. Therefore, a lithium-sulfur battery is considered as an ideal energy storage unit for the future energy storage system. However, the lithium polysulfide intermediates generated in the charging and discharging process are easily soluble in the electrolyte, resulting in a loss of active materials and an increase in the electrolyte viscosity. In addition, the dissolved lithium polysulfide is inclined to migrate between positive and negative electrodes, and reacts with the lithium negative electrode, causing irreversible loss of active substance sulfur, greatly reducing the battery life and safety. This phenomenon is called the shuttle effect, which hinders the commercialization process of lithium-sulfur batteries. In recent years, researchers have attempted to solve this problem through physical adsorption, chemical action, and external field constraint, and achieved impressive progress. This work summarizes the research progress of capturing lithium polysulfide, and compares the characteristics of each approach and its impact on the electrochemical performance of lithium-sulfur batteries. Whether it is the physical constraint of the porous structure of carbon materials, the chemical interaction between the carrier materials and lithium polysulfide, or the adsorption of electric and magnetic fields on lithium polysulfide, lithium polysulfide is fixed on the positive side and to inhibit its dissolution and diffusion to the negative electrode. Capturing lithium polysulfide by external magnetic field, internal magnetic field induced by magnetic particles, and internal electric field generated by spontaneous polarization of ferroelectric materials is also highlighted. Finally, the challenges in capturing lithium polysulfide and the possible solution are prospected. Related Articles | Metrics

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Forced oxidation of calcium sulfite and the influence of impurities in wet desulfurization by calcium carbide slag Yuewu ZHENG Ziheng MENG Lingxian LIAN Jiliang HAN Liwen ZHAO Xingguo WANG Gang XING Ganyu ZHU Huiquan LI The Chinese Journal of Process Engineering    2023, 23 (12): 1725-1738.   DOI: 10.12034/j.issn.1009-606X.223048 Abstract （162）   HTML （3）    PDF （9117KB）（91）       Knowledge map    Save The main component of calcium carbide slag (CCS) is calcium hydroxide [Ca(OH)2], which can replace limestone ore for wet flue gas desulfurization, but the desulfurization byproducts of calcium sulfite particles are small because of the strong alkalinity of CCS, which may affect the oxidation of calcium sulfite and the crystallization of calcium sulfate (CaSO4). The effects of different process conditions on particle size, oxidation rate, water content, and microcosmic appearance in the process of calcium sulfate oxidation and gypsum crystallization were systematically investigated, and the optimal process condition (calcium sulfate content of 5 g/L, aeration rate of 400 mL/min, initial pH value of 5.5, reaction temperature of 40℃, and reaction time of 4 h) was obtained. The byproduct of desulfurization gypsum (mainly calcium sulfate dihydrate) with large particle size, low water content, high purity, and uniform appearance was obtained under the optimal condition, which is conducive to the subsequent resource utilization of desulfurization gypsum. The leaching sequence of each element in the CCS under the actual operating pH conditions of the CCS slurry (acidic conditions) is Na>Ca>Mg>Si>Fe>Al. The effects of impurities of Na, Mg, Si, Fe, and Al in the CCS on the oxidation process of calcium sulfate and the crystallization of calcium sulfate were investigated under the above optimal reaction condition. The results indicated that Mg, Si, and Fe in the CCS had a significant promotion effect on the oxidation rate of calcium sulfate, while Al and Na in the CCS inhibited the oxidation of calcium sulfate. At the same time, the addition of Si impurity had almost no effect on the crystallization of calcium sulfate, the addition of the impurities of Mg, Fe, and Na had less effect on the crystallization of calcium sulfate, and the addition of Al impurity had a significant adverse effect on the crystallization of calcium sulfate. In this study, the CCS-based calcium sulfate was used as the raw material, and the study of calcium sulfate oxidation and gypsum crystallization was carried out, providing theoretical guidance for the forced oxidation process in the actual industrial desulfurization. Related Articles | Metrics

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Efficiently CO 2 capture by superbase ionic liquid-amine-water blending solvents Kaixuan WANG Tao LI Yu LI Yinge BAI Shaojuan ZENG Baozeng REN Xiangping ZHANG Haifeng DONG The Chinese Journal of Process Engineering    2023, 23 (5): 781-789.   DOI: 10.12034/j.issn.1009-606X.222175 Abstract （159）   HTML （5）    PDF （1539KB）（61）       Knowledge map    Save The increasing carbon dioxide (CO2) emissions have a serious impact on climate change. As one of the most important technologies for achieving carbon emission reduction, CO2 capture has attracted widespread attention from academia and industry. Chemical absorption is an effective and suitable CO2 capture technology for low CO2 partial pressure areas, such as flue gas. The commonly used flue gas CO2 capture method in industry is the monoethanolamine (MEA) absorption method, which has the advantages of mature technology, simple operation, and high absorption rate, but the disadvantages are high energy consumption for regeneration and easy degradation of absorbent. The development of an efficient, low-energy, and environmentally-friendly absorbent has been a difficult and hot research topic in this field. As a class of green solvents, ionic liquids (ILs) provide a new opportunity for CO2 capture due to their tunable structure, fast reaction rate, and high absorption capacity, and have become a promising solvent for CO2 capture. However, the low CO2 absorption capacity of conventional ILs and the high cost and viscosity of functionalized ILs have limited the industrial application of ILs in CO2 capture. ILs mixed with organic amine are a potential CO2 capture solvent, which can not only maintain high absorption capacity but also avoid the problem of viscosity and high cost. In this work, a superbase IL (1,8-diazabicyclo[5,4,0]undec-7-ene imidazole, [HDBU][Im]) was mixed with MEA to obtain IL blending solvents to improve the CO2 absorption capacity of the absorbent and reduce the viscosity of the solvent after absorption. The effects of IL concentration, absorption temperature, and CO2 partial pressure on the CO2 capture performance of the IL blending solvents were investigated, and the physical properties, such as density and viscosity of the IL blending solvents under different CO2 absorption capacities were analyzed. The results showed that 30wt% MEA+10wt% [HDBU][Im] had a better absorption capacity, and at the temperature of 40℃, the CO2 absorption capacity was 0.1453 g CO2/g solvent, and the viscosities before and after CO2 absorption were 2.312 and 4.303 mPa?s, respectively, which were significantly lower than those of IL absorbents. Therefore, it is a promising absorbent for CO2 capture. Related Articles | Metrics

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The controllable preparation of SiO 2 microspheres by Stöber method in the microreactor Yangping YU Mei YANG Mingzhi LI Guangwen CHEN The Chinese Journal of Process Engineering    2023, 23 (6): 908-917.   DOI: 10.12034/j.issn.1009-606X.222290 Abstract （157）   HTML （3）    PDF （41018KB）（69）       Knowledge map    Save SiO2 microspheres were synthesized in a controlled manner via St?ber method by using a microreactor and a batch reactor in series to achieve rapid mixing of the reactant and flexible adjustment of the aging time. The phase and morphology of the as-prepared SiO2 were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscope (TEM). The results showed that the mean particle size and dispersity of the SiO2 microspheres depended on the competition between the tetraethyl orthosilicate (TEOS) hydrolysis reaction and the silanol monomer condensation reaction, and were also significantly influenced by the mixing rate of reactants in the initial period. The monomer addition model was employed to explain the experimental results. When the aging temperature increased from 25℃ to 75℃, the mean particle size of SiO2 microspheres decreased from 472 nm to 200 nm, with little change in dispersity. Because the reaction rates of TEOS hydrolysis and silanol monomer condensation increased with the increasing aging temperature, the supersaturation degree of silanol monomer immediately exceeded the critical supersaturation for homogeneous nucleation at higher aging temperatures. A large number of nuclei was formed, causing the formation of smaller microspheres. When the concentration of aqueous ammonia was increased from 0.8 mol/L to 5.6 mol/L, the mean particle size of SiO2 microspheres increased from 34 nm to 261 nm, and the dispersity became better. At higher ammonia concentration, more ethoxyl groups were hydrolyzed in a single TEOS molecule to produce silanol monomers with more silanol groups. This kind of silanol monomers could condense into siloxane networks at a faster rate, leading to larger particle sizes. When the water concentration increased to 35.6 mol/L or the TEOS concentration increased to 1.0 mol/L, multiple nucleation or continuous nucleation occurred in the solution, resulting in a dramatic deterioration of the dispersity of SiO2 microspheres. Increasing the Reynolds number (Re) or reducing the channel inner diameter led to the formation of monodisperse SiO2 microspheres, which could be attributed to the faster mixing between the reactants. Related Articles | Metrics

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Research status and prospect of key installations and flow characteristics of pneumatic conveying Jiawei ZHOU Xiangyu YAN Zebing ZHENG Qinghui WANG Linjian SHANGGUAN The Chinese Journal of Process Engineering    2023, 23 (5): 649-661.   DOI: 10.12034/j.issn.1009-606X.222192 Abstract （157）   HTML （1065）    PDF （3837KB）（121）       Knowledge map    Save Pneumatic conveying has the characteristics of environmentally friendly, operational safety, spatial intensification, flexible configuration, and easy to automate. In addition, this bulk material handling method also has the advantages of quantitative conveying, conveniently dispersing or centralized conveying, and inert gas protection conveying for unstable materials. The aforementioned characteristics pneumatic conveying to a commonly clean conveying technology for bulk materials. At the same time, pneumatic conveying has been widely applied in chemical, food, pharmaceutical, energy industries, and other fields. However, this method also has a few problems, such as high energy consumption, particle degradation, and pipe erosion. The fundamental cause of the disadvantages lies in the complex conveying process, transient state of particle conveying, and difficulty in accurate prediction. Therefore, the multi-means characterization and prediction of material conveying characteristics in different conveying processes have always been the hot points of this technology. It is well known that the equipment composition is the foundation of pneumatic conveying system performance. In addition, the feeding device is one of the most important factors for conveying processes. In this meaning, this work first summarized the structure of the pneumatic conveying system and the structural characteristics of commonly used feeding devices. Then, this work reviews the application and research of the numerical simulation methods including the two-fluid model in the computational fluid dynamics and the coupling simulation of the computational fluid dynamic discrete element method (CFD-DEM). The application conditions, merits, and demerits of the common numerical method are discussed. What is more, the research and application status of measuring devices commonly used in pneumatic conveying are summarized, including electrical capacitance tomography (ECT), pressure determination, and acoustic emission. Meanwhile, the study mainly focuses on flow pattern evolution and pressure loss in the conveying system, as well as some interesting study points of pneumatic conveying, which are well explored. Finally, several thinking points for future research on this technology are discussed. Related Articles | Metrics

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Preparation and electrochemical properties of perovskite-type La(Co 0.2 Cr 0.2 Fe 0.2 Mn 0.2 Ni 0.2 )O 3 high-entropy oxide Xia SHAO Yanggang JIA Jie CHENG Daolai FANG Aiqin MAO Jie TAN The Chinese Journal of Process Engineering    2023, 23 (5): 771-780.   DOI: 10.12034/j.issn.1009-606X.222242 Abstract （156）   HTML （7）    PDF （11914KB）（62）       Knowledge map    Save Perovskite-type (ABO3) oxides have attracted great attention as one of the most promising energy storage materials owing to the advantage of good electric conductivity and electrochemical activity. However, severe volume change for conventional metal oxides during the electrochemical reaction processes is likely to result in severe polarization of the electrodes and inferior kinetic properties as well as fast capacity fading. Transition-metal-based high-entropy oxides (HEOs) are an emerging kind of single-phase solid solution materials, which exhibit improved lithium storage properties and excellent cycling stability due to the multi-principal synergistic effect and entropy stabilization. In this work, transition metal-based perovskite-type La(Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)O3 HEO lithium-ion batteries (LIBs) anode material are prepared by solid-state reaction method and compared with the conventional binary perovskite-type LaCoO3. The crystal structure, microstructure, and elemental composition of HEOs are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) in detail. The electrochemical properties of LIBs anode are elucidated. XRD results show that the impurity phase in the perovskite structure disappears gradually and the crystallinity increases with the increase of reaction temperature from 750℃ to 950℃ and sintering time from 30 min to 4 h. SEM/EDS results confirm the as-synthesized spherical powder has a homogeneous distribution throughout the entire particle at the micrometer level. The electrochemical performance study illustrates that the La(Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)O3 anode material delivers higher specific capacity, excellent cycle stability, and rate performance than LaCoO3 mainly due to the entropy-stabilized crystal structure and the multi-principal synergistic effect. The reversible specific capacity of La(Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)O3 is 331 mAh/g after 100 cycles at 200 mA/g currrent density, which is fairly approximate to the theoretical capacity of 332 mAh/g, while the reversible specific capacity of LaCoO3 is only 185 mAh/g. Moreover, the capacity retention rates of La(Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)O3 and LaCoO3 are 72.5% and 61.6% at 1000 mA/g. This strategy on high entropy chemistry not only opens new insights into the development of advanced electrode materials but also provides a new design concept and strategy for the low content cobalt or free cobalt direction of electrode materials. Related Articles | Metrics

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Preparation of nano-calcium carbonate intensified by CO 2 micro bubble and transfer-reaction analysis Liheng WANG Xiaoping GUAN Ning YANG Zuze MU The Chinese Journal of Process Engineering    2023, 23 (9): 1313-1324.   DOI: 10.12034/j.issn.1009-606X.222450 Abstract （156）   HTML （3）    PDF （2491KB）（91）       Knowledge map    Save Carbonization is one of the common methods to prepare nano calcium carbonate. Controlling the particle size and particle size distribution of calcium carbonate is the key to the preparation of high-quality nano-calcium carbonate by carbonization. Different operating conditions have different effects on the reaction products. The particle size and size distribution of calcium carbonate can be effectively controlled by controlling different reaction conditions to improve the mass transfer and reaction conditions in the slurry. In batch-operated bubble column reactor, gas flow rate and bubble size are factors affecting mass transfer. This study investigates the influences of operation condition (gas flow rate, initial slurry condition), bubble type (ordinary bubble, micro bubble) on carbonation reaction rate and particle size distribution of calcium carbonate. Furthermore, the effects of bubble type on the stable region and abrupt change region in carbonation reaction process are analyzed. The experimental results show that when using ordinary bubble, the increase of CO2 flow rate accelerates the reaction process and reduces the particle size of calcium carbonate, but it does not affect the time of abrupt change region. With increasing the slurry concentration, the particle size first decreases and then increases in small-diameter column with ordinary bubble. However, when using micro bubble, the particle size of calcium carbonate is significantly reduced, and the time of abrupt change region decreases with the increase of gas flow rate. Moreover, the CO2 flow rate is no longer an influential factor on calcium carbonate particle size, which means that the gas-liquid mass transfer process is not the rate controlling step of carbonation reaction. This study provides some references for studying the application of micro bubbles in calcium carbonate crystallization. Related Articles | Metrics

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DEM modeling of resonant motion of particles inside moving bed Qinjian SHEN Shijie DONG Dancheng ZHANG Hui GUO Yinling SONG Xiaoxing LIU The Chinese Journal of Process Engineering    2023, 23 (6): 826-836.   DOI: 10.12034/j.issn.1009-606X.222161 Abstract （155）   HTML （5）    PDF （5476KB）（141）       Knowledge map    Save Moving beds are ubiquitous in various process industries. Thoroughly understanding and accurately characterizing the complex flow behavior of granular materials from the component particle scale is obviously of great significance for the design, scale-up, and optimization of moving beds. In this work, the flow behavior of granular assemblies in moving beds under both the funnel flow and semi-mass flow discharge regimes are investigated by performing three-dimensional discrete element method (DEM) simulations, with a focus on the possible similarities and differences between the fluctuating characteristics and also the corresponding underlying mechanisms of the transient motions of particles under these two discharging conditions. The reliability of the DEM simulation is verified by comparing the predicted evolutions of the boundary of the flowing zone and also its characteristic width with experimental results. The simulation results demonstrate that under both discharge conditions, the temporal variations of the spatially averaged axial velocity of particles in the upper part of the flowing zone present notable non-random fluctuating characteristics, manifested by the appearance of a clear peak in the Fourier spectrum of the time series of spatially averaged particle axial velocity. The spatial correlation analysis results show that the temporal fluctuations of the spatially averaged axial velocity of particles in different axial regions of the upper part of the flowing zone are closely correlated, suggesting the occurrences of resonance under both discharging types. The delayed correlation analyses of the time series of the spatially averaged axial velocities of particles in different axial zones indicate that such resonant behavior originates from a bottom zone right above the outlet. The delayed correlation analyses of the time series of the spatially averaged particle axial velocity and the spatially averaged particle contact force demonstrate that there exists a strong correlation between the temporal fluctuations of these two parameters, and the latter precedes the former, which hints that the observed resonance could be ascribed to the free-fall arch mechanism. In brief, the presented simulation results clearly demonstrate that resonance can occur during both funnel and semi-mass flow discharges and there is no intrinsic difference between the resonant features of particles under these two discharging conditions. Related Articles | Metrics

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Research progress in the preparation of porous biomass carbon materials and their applications in supercapacitors Xuemin ZHANG Guanyu HE Shaoqi YIN Tingting HUANG Jinping LI Jian ZHENG The Chinese Journal of Process Engineering    2024, 24 (2): 127-138.   DOI: 10.12034/j.issn.1009-606X.223036 Abstract （154）   HTML （13）    PDF （1013KB）（93）       Knowledge map    Save The biomass carbon material is a kind of green and renewable energy material. Its efficient utilization is of great significance for the sustainable development of the energy environment and the green and low-carbon transition of energy. Biomass carbon materials are widely used in energy storage and conversion, catalysis, adsorption, and many other fields due to their porous nature, abundant functional groups, large specific surface area, excellent electrochemical performance, low cost, and renewable. However, the properties of biomass carbon materials are not only closely related to the microstructure, but also the heteroatom doping has an important impact on the structure and electrochemical properties of biomass carbon materials. The accurate structure regulation of biomass carbon materials is an effective way to improve their electrochemical performance. In this work, the preparation methods of biomass carbon materials and their applications in supercapacitors are comprehensively reviewed, and the relationship between the structure and properties of porous carbon materials is discussed. On this basis, the influence mechanism and rules of different conditions, and different preparation processes (such as material selection, material treatment, and activation mode) on the structure characteristics of biomass carbon materials are analyzed. In this review, the mechanism and rules of the influence of the structure characteristics on the electrochemical properties of porous biomass carbon materials are described in detail, and the preparation process and performance regulation of porous biomass carbon materials need to be perfected and improved. Finally, the main development directions of preparation technology and electrochemical properties of porous biomass carbon materials in the future are pointed out. Related Articles | Metrics

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Research and industrialization of conductive additive technology in the field of new energy batteries Peiling YUAN Xingxing DING Peng GUO Caili ZHANG Rui HU The Chinese Journal of Process Engineering    2023, 23 (8): 1118-1130.   DOI: 10.12034/j.issn.1009-606X.223115 Abstract （149）   HTML （3）    PDF （2082KB）（71）       Knowledge map    Save Secondary batteries have been widely developed and used in various fields, such as large-scale energy storage, portable electronic devices, and electric vehicles. Conductive additives, as an important component of lithium-ion batteries, could increase and maintain the electronic conductivity of the electrodes by constructing a conductive network, which will effectively improve the electrochemical performance of batteries. Although conductive additives account for a relatively small proportion of the cost of lithium batteries (around 2%), compared to the trillion level lithium battery industry, conductive additives have also become a trillion level industry. At present, the mainstream conductive additives are carbon black, conductive graphite, vapor grown carbon fiber (VGCF), carbon nanotubes, and graphene. They are ideal conductive additives for lithium-ion batteries because of superior properties such as low weight, high chemical inertness, and high specific surface area. Among them, carbon black, conductive graphite, and VGCF are traditional conductive additive materials that form point and line contact conductive networks between active materials; carbon nanotubes and graphene belong to new conductive additive materials, which respectively form wire and surface contact conductive networks between active materials. Compared to a single conductive agent, composite conductive agents create synergistic effects between different conductive agents, thus exhibiting better performance. Therefore, we believe that the new conductive agent has a highly unified relationship with traditional conductive agents. Taking into account both cost and performance, the future conductive agent system will gradually shift from singularity to multiple composites. In addition, China's conductive agents have long relied on imports. In recent years, some excellent enterprises have gradually broken through process barriers in preparation methods and dispersion technologies, accelerating the process of localization. This article will discuss the related work of using carbon nanomaterials as conductive additives in the field of batteries and improving their electrochemical performance. Then, further discuss the industrialization status and prospects of conductive additives. Related Articles | Metrics

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Numerical study on CO 2 bubble rise process coupled with mass transfer Donghao PEI Lexiang ZENG Mengdie GAO Jincheng RUAN Jun CAO The Chinese Journal of Process Engineering    2023, 23 (9): 1244-1255.   DOI: 10.12034/j.issn.1009-606X.222385 Abstract （147）   HTML （5）    PDF （15818KB）（116）       Knowledge map    Save Gas-liquid two-phase flow and mass transfer phenomena widely exist in nature and daily life. Studying the mass transfer process of bubbles in water is of great significance for understanding the mass transfer mechanism and exploring the enhancement of the mass transfer process. The volume of fluid (VOF) method was used to simulate the rising process of CO2 bubble in still water, and the mass transfer process was considered by a user defined function program. The instantaneous velocity, mass transfer coefficient, CO2 dissolved amount, and mass transfer wake changes of bubbles with different initial diameters during the rising process were studied. In the process of bubble rising, the transverse velocity changed periodically and the oscillation amplitude decreased with the increase of bubble initial diameter, while the longitudinal velocity increased with the increase of the bubble initial diameter. Between 3.5 mm and 6 mm, with the increase of the bubble diameter, the CO2 dissolved amount increased, and the wake stream showed three states: symmetrical state, transitional state, and periodic shedding. The critical Re number of 3.5~6 mm bubble wake transition increased with the increase of bubble initial diameter, the frequency of wake periodic shedding was 17~22 Hz, and the departure frequency decreased with the increase of bubble initial diameter. The bubble wake was consistent with the mass transfer wake. With the increase of the bubble initial diameter, the influence range of the bubble mass transfer wake increased. Related Articles | Metrics

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Research process of multivesicular liposomes Xing FAN Hua YUE Xiaojun WANG The Chinese Journal of Process Engineering    2023, 23 (10): 1371-1380.   DOI: 10.12034/j.issn.1009-606X.222431 Abstract （143）   HTML （11）    PDF （2032KB）（75）       Knowledge map    Save Since 1983, multivesicular liposomes (MVLs), as a member of the liposome family, have been of interest in the biomaterials and medical fields. MVLs have multiple aqueous compartments separated by phospholipid bilayers and an internal aqueous phase of up to 90%. They also have the advantages of reducing the number of injections, extending the duration of drug action, and improving patient compliance. So far, most of the MVLs reported in the literature are above 10 μm in size and have made good progress mainly in the encapsulation of analgesic drugs. This review provides an overview of the preparation methods, characterization methods, and drug release mechanisms of MVLs that have been reported in the literature in the last decade. There are relatively several methods for preparing MVLs, including the double emulsification method, spray atomization technique, and electroforming method. Currently, the main characterization methods used for MVLs are optical/fluorescent confocal imaging, scanning electron microscopy imaging, determination of particle size distribution, entrapment efficiency, and determination of zeta potential. Because of the large volume of the internal aqueous phase of MVLs and the high hydrophilic drug encapsulation rate of the internal vesicles, the individual vesicles gradually rupture and the hydrophilic drug gradually gets released during in vitro release, with a three-phase release pattern of sustained release. This review also summarizes the current status of clinical studies and types of commercialized products. At present, the application of MVLs regarding analgesics has reached stages II-IV, and three commercialized formulations have entered the clinic with satisfactory results. Moreover, this review summarizes the current progress in applied research, mainly in the delivery of anticancer drugs, analgesic drugs, and protein peptides. Last but not least, the challenge and prospects regarding small-sized MVLs, diverse biomedical applications, and scale-up strategies are proposed. Related Articles | Metrics

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Study on performance of forced circulating water electrolytic cell coupled with electrochemistry and multiphase flow model Xudong DUAN Simin WANG Jian WEN The Chinese Journal of Process Engineering    2023, 23 (6): 880-888.   DOI: 10.12034/j.issn.1009-606X.222318 Abstract （136）   HTML （5）    PDF （10405KB）（95）       Knowledge map    Save Hydrogen production from electrolytic water technology is an important way to solve the future energy crisis and realize green development. Among them, alkaline electrolytic water has simple structure and low cost, which is suitable for large-scale development. The concentration polarization caused by the bubble behavior in the alkaline electrolytic cell has a great impact on the performance of the electrolytic cell, reducing the contact area between the electrode and the electrolyte and increasing the resistance and the energy consumption of hydrogen production from electrolytic water. But most of the numerical simulation studies on electrolytic water do not consider the impact of the flow behavior of gas-phase products. In this work, the electrochemical model is coupled with the gas-liquid two-phase flow model, the drag force, lift force and bubble dispersion force are included in the equation describing the gas-phase volume force, and the influence of concentration polarization is considered. The gas production process of the forced circulation alkaline electrolytic cell is simulated, and the calculation results are more in line with the real flow state. The influence of operating conditions on the performance of the electrolytic cell is further studied. It is calculated that with the increase of electrolyte temperature from 60℃ to 80℃, the average current density increases by 3.84%, and the uniformity of current density distribution deteriorates. When the electrolyte flow rate is increased from 0.10 m/s to 0.30 m/s, the average current density and distribution uniformity can be improved simultaneously, and the average current density is increased by 0.64%. With the increase of potassium hydroxide concentration from 1 mol/L to 6 mol/L, the current density increases by 40.21%, but the uniformity of current density distribution deteriorates. And among the three operating variables, the electrolytic performance is the most sensitive to the concentration of potassium hydroxide in electrolyte. This work provides guidance for the internal mechanism research and operation parameter design of electrolytic water. Related Articles | Metrics

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Structural optimization and flow field analysis of agitated extraction column based on CFD Shenfeng YUAN Lingzhen JIN Zhirong CHEN Hong YIN The Chinese Journal of Process Engineering    2023, 23 (5): 681-690.   DOI: 10.12034/j.issn.1009-606X.222269 Abstract （135）   HTML （5）    PDF （2958KB）（65）       Knowledge map    Save In order to reduce the axial backmixing and increase the throughout flux in the agitated extraction column, the column was modified on the basis of the agitated sieve plate extraction column, and a new agitated extraction column with relatively light backmixing is proposed. Through the simulation of residence time distribution, combined with backmixing model and flow field analysis, the effects of annulus area, annulus position, opening mode, and the height of settling compartments on fluid flow characteristics are studied. The results show that the inter-stage rotating baffles can effectively inhibit axial backmixing in the column, and the larger the diameter of baffles, that is the narrower the annulus in the column, the smaller the backmixing. The optimum diameter of the inter-stage baffles in the agitated extraction column with a diameter of 50 mm should be more than 25 mm, that is, the ratio of the annulus area to the cross-sectional area of the column should not exceed 25%. Under a certain annulus width, the annulus position has little influence on the fluid flow. When the diameter of the inter-stage baffles is roughly equal to the impellers', the backmixing in the column reaches the smallest. Different opening modes also affect the flow characteristic in the column. Both perforated stators and perforated inter-stage baffles increase backmixing, especially the perforated inter-stage baffles just below the impellers. Under the condition of a certain annulus area, the agitated extraction column A6 without pores in stators and inter-stage baffles has the smallest backmixing and its structure is simple. However, if the liquid-liquid dispersion and the dead zone of the light phase are taken into consideration, the agitated extraction column B3 and B4 not only have relatively low backmixing, but also could improve the throughout flux, whose performance can be further studied. The settling compartments can reduce the backmixing, and the higher the height of settling compartments, the smaller the backmixing. Considering the equipment cost in practical application, the optimum ratio of the height of settling compartment to column diameter should be about 0.7. Related Articles | Metrics

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Effect of conical distribution plate with slit hole on flow characteristics in fluidized reactor Tiancheng WANG Gong CHEN Dexi WANG Lixin SHAO The Chinese Journal of Process Engineering    2023, 23 (10): 1390-1400.   DOI: 10.12034/j.issn.1009-606X.222472 Abstract （133）   HTML （5）    PDF （1471KB）（99）       Knowledge map    Save Water pollution has gradually become one of the prominent problems restricting the harmonious development of urban ecosystem. At present, the development of efficient wastewater treatment technology has important practical significance to alleviate this problem. Wastewater treatment reactor is the core equipment of wastewater treatment, and the internal flow characteristics affected by its structure have an important impact on water treatment efficiency. Fluidization reactor has become a common sewage treatment equipment because of its high heat and mass transfer rate. In view of the liquid phase back mixing and uneven liquid-solid mixing still exist in fluidized reactor for wastewater treatment. Based on the mobile biofilm wastewater treatment technology and the concept of maximizing the space utilization of integrated wastewater treatment equipment, a rectangular fluidized reactor with slit hole conical distribution plate was designed. The orifice area of the distribution plate gradually increased from the center of the reactor to the outside, and the Euler-Euler multiphase flow model and RNG k-ε turbulence model were used for numerical simulation of the fluidized reactor with a conical distribution plate with slit holes. The effect of the distribution plate structure on the distribution of particles in the reactor was studied by the arrangement of the holes and the cone angle of the slit hole conical distribution plate. The results showed that the conical distribution plate with slit holes can solve the problems of liquid-phase backmixing and uneven liquid-solid mixing, form multiple ring core flows in the reactor, improve the uniformity of particle distribution, and strengthen the liquid-solid mixing. Based on the comprehensive evaluation of particle volume fraction, flow rate, and bed density standard difference, the optimal hole distribution mode of the slit conical distribution plate was determined to be perpendicular to the central axis, and the optimal fluidization effect of the reactor appeared under the cone angle of 120°. Related Articles | Metrics

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Numerical simulation of flow field characteristics enhanced by cylindrical vortex generator in impinging stream reactor Jianwei ZHANG Hongwen WEI Xin DONG Ying FENG The Chinese Journal of Process Engineering    2023, 23 (5): 672-680.   DOI: 10.12034/j.issn.1009-606X.222193 Abstract （132）   HTML （4）    PDF （1984KB）（84）       Knowledge map    Save Impinging stream reactor is widely used in absorption, extraction, and preparation of ultrafine powders due to its good mixing performance. The flow field characteristics of impinging stream reactor are closely related to the mixing performance. Based on impinging stream reactor, the use of a vortex generator and other turbulence elements to improve the flow state of the flow field, enhance the flow performance, and mixing effect of impinging stream reactor needs further research. In this work, the numerical simulation method is used to analyze the flow field characteristics of impinging stream reactor with a cylindrical vortex generator and optimize the size and location parameters of the cylindrical vortex generator. The effects of size and location parameters of cylindrical vortex generators on flow field structure, velocity distribution, turbulence scale, and mixing performance of impinging stream reactor are investigated. The results show that when the diameter of cylindrical vortex generator D is equal to 10 mm, the number of vortices in the impinging stream reactor is the largest, and the influence range of the vortex system is the widest. When the diameter of cylindrical vortex generator D is less than 10 mm, the number of vortices decreases. When the diameter of cylindrical vortex generator D is greater than 10 mm, the influence range of the vortex system decreases. The number of vortexes in the impinging stream reactor decreases and the influence range of the vortex system increases with the increase of the transverse spacing of the column vortex generator. The radial velocity, turbulence scale, and mixing intensity of impinging stream reactor first increase and then decrease with the increase of transverse and longitudinal spacing of cylindrical vortex generators. When the transverse spacing of the cylindrical vortex generator K is equal to 5 mm and the longitudinal spacing of the cylindrical vortex generator J is equal to 70 mm, the mixing effect of the impinging stream reactor is the best. Related Articles | Metrics

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Effect of sintering time on microstructure evolution and magnetic properties of Fe-Si/SiO 2 soft magnetic cores Hui KONG Rui WANG Zhaoyang WU Yihai HE Haichuan WANG Nachuan JU The Chinese Journal of Process Engineering    2023, 23 (6): 898-907.   DOI: 10.12034/j.issn.1009-606X.222166 Abstract （132）   HTML （1）    PDF （51402KB）（57）       Knowledge map    Save Soft magnetic cores consist of a highly saturated ferromagnetic powder core and a high resistivity insulating shell, resulting in core-shell heterogeneous structure, and could therefore have high permeability, high saturation magnetization, high resistance, and low eddy current loss, which is the basis for limiting eddy current operation and reducing high-frequency losses during AC magnetization. Therefore, maintaining the integrity and homogeneity of the core-shell heterostructure within soft magnetic cores during the sintering molding process is critical for optimizing the magnetic properties. In this work, Fe-Si/SiO2 soft magnetic cores were prepared by hot-pressing sintering, and the evolution behavior of Fe-Si/SiO2 soft magnetic cores' core-shell heterostructure with sintering time and the influence on the magnetic properties were systematically studied. These obtained results showed that the Fe-Si/SiO2 soft magnetic core core-shell heterostructure tended to be more complete with the prolongation of the sintering time range from 3 min to 10 min, and the SiO2 insulating layer began to crystallize when the sintering time was up to 9 min. When the sintering time was greater than 11 min, the core-shell heterostructure began to collapse due to the overheating phenomenon caused by the superposition of two thermal effects in the gradient temperature field during the hot-pressing sintering process. Under the condition that the core-shell heterostructure remained intact and dense, the Fe-Si/SiO2 soft magnetic cores with a sintering time of 10 min exhibited the best magnetic properties among all 8 samples, the saturation magnetization was 220.9 emu/g, the resistivity was 0.72 mΩ?cm, and the total loss in 10 mT and 100 kHz was 627.5 kW/m3. Compared to the sample with destroyed core-shell heterostructures (13 min), the total loss decreased by about 38.7%, of which the eddy current loss decreased by about 33.1%, and the hysteresis loss decreased by about 14.7%. Related Articles | Metrics

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Multimodal process fault monitoring of LNS-PCA based on local information Zhongshuai YUAN Sitong SUN The Chinese Journal of Process Engineering    2023, 23 (5): 790-798.   DOI: 10.12034/j.issn.1009-606X.222183 Abstract （131）   HTML （3）    PDF （1476KB）（73）       Knowledge map    Save Led by market demand, the industrial process needs to switch to a variety of working modes, the industrial process detection system is becoming more and more complex, and data often presents the characteristics of the multi-mode complex distribution. It is of great significance to study multi-mode fault detection technology for ensuring the safe operation of industrial processes. The statistical process control method represented by principal component analysis (PCA) is a typical fault detection method based on the data drive. It is widely used to analyze whether there is a fault in the production process through the data collected by the system, which does not depend on prior knowledge and mathematical model. However, it requires that the data must conform to the Gaussian distribution, which cannot be satisfied in the multi-mode production process. To improve the performance of industrial process fault detection and eliminate the multi-modal and non-Gaussian characteristics of data, this work proposes a multi-mode process fault monitoring method based on local information LNS-PCA (LLNS-PCA). Firstly, the Gaussian mixture model (GMM) was used to divide the sample into several local samples. Secondly, for each sample data, the mean and variance of the local sample are standardized to make the data follow the Gaussian distribution. Finally, the data of each local sample were combined and PCA model was trained to obtain T 2 statistics and SPE statistics for fault monitoring. The LLNS-PCA algorithm was validated with numerical examples and penicillin production data as training samples. Under the same conditions, PCA, KPCA, and LNS-PCA are used to detect anomalies. The results showed that the LNS-PCA based on local information proposed in this work has a better detection effect. In conclusion, LLNS-PCA was superior to PCA, KPCA, and LNS-PCA, which was worth promoting. Related Articles | Metrics

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Experimental study on filtration performance of countercurrent moving bed filter Kai XING Han LÜ Yiping FAN Chunxi LU Fuwei SUN The Chinese Journal of Process Engineering    2023, 23 (5): 662-671.   DOI: 10.12034/j.issn.1009-606X.222143 Abstract （130）   HTML （3）    PDF （13278KB）（43）       Knowledge map    Save Granular bed filtration is one of the most promising high-temperature filtration technologies and has good prospects for application in environmental protection or in industrial production. Compared to the fixed bed, the moving bed filters with the stability for long-cycle operation are more in line with practical requirements. The influences of the superficial gas velocity and the regeneration gas velocity on the gas-solid countercurrent moving bed filter are investigated by cold model experiment. Under the dust-free operating conditions, it is found that the bed pressure drop increased parabolically with the superficial gas velocity. It can also be estimated by the modified Ergun formula. Under the operating condition of dust-leaden, on the other hand, it is proved that the variation trend of dust removal efficiency is the same as that of gas residence time. It is positively correlated with the regeneration gas velocity. The gas residence time is mainly influenced by the superficial gas velocity and the accumulation of dust in the filter, which varies as the experiment proceeds. The pressure drop of the bed is positively correlated with the gas velocity whereas is negatively correlated with the gas regeneration velocity. The experimental results show that the dust collection efficiency of this equipment is fairly high. When the superficial gas velocity ranges from 0.122 m/s to 0.305 m/s, with the inlet concentration of 8.175 g/m3, the dust removal efficiency is generally higher than 98.0%. The bed pressure drop always maintains dynamic equilibrium within a certain range, and the maximum rise does not exceed ±0.05 kPa. The fraction efficiency for the fine dusts smaller than 13 μm also achieves 99.99%. Related Articles | Metrics

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Research progress of flotation activator for complex copper oxide minerals Haoxiang WANG Peilun SHEN Jinpeng CAI Xiaodong JIA Rong PENG Dianwen LIU The Chinese Journal of Process Engineering    2023, 23 (10): 1381-1389.   DOI: 10.12034/j.issn.1009-606X.222336 Abstract （129）   HTML （10）    PDF （5380KB）（103）       Knowledge map    Save Copper is widely used in industry because of its excellent physical and chemical properties.At present, with the depletion of copper sulfide resources, the development and utilization of copper oxide resources has gradually become the focus of research. As an important source of copper metal extraction, the key to efficient recovery of copper oxide ore is the activation process. However, the existing copper oxide resources have the characteristics of high oxidation rate, complex mineral composition and easy sludge, which makes the beneficiation more difficult. The classical sulfidization-xanthate flotation method can't meet the current requirements of complex copper oxide ore resource separation. In addition, the mechanism of activator acting on mineral surface and the unclear explanation of crystal structure of activated products restrict the development of the theory and method of copper oxide ore separation to some extent. In recent years, a variety of new activators or combination activators have been reported in reference for the complex and difficult-to-beneficiated copper oxide resources. Scholars have made a deeper research and elaboration on the activation mechanism of copper oxide ore based on the existing activation theory, and put forward a variety of effective and practical new theories and methods, which have solved the problem of complex copper oxide ore beneficiation to some extent. In this review, by combing the development of activator for copper oxide ore in recent years, the application and activation mechanism of new activator and new activation method are summarized, aiming at enriching the theoretical system of efficient flotation of copper oxide ore and providing reference for production practice. Related Articles | Metrics

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Numerical investigation of effects of bath flow on melting behavior of scrap Xiaobin ZHOU Yu TENG Wanxing WANG Qiang YUE Zhenghai ZHU The Chinese Journal of Process Engineering    2023, 23 (9): 1256-1267.   DOI: 10.12034/j.issn.1009-606X.222403 Abstract （128）   HTML （4）    PDF （24471KB）（83）       Knowledge map    Save Nowadays, more and more scrap is required to be added in the bath of the converter accompanied by the increasing requirements on the environment and increasing volume of available scrap in China. Consequently, the melting rate of the scrap would be significant if a large amount of scrap is added into the bath for the steelmaking process. The carbon content, temperature, and flow of the bath are the main factors that influence the scrap melting process in a bath of hot metal. The current study mainly focused on the effects of bath flow on the melting behavior based on a scrap melting process performed in the experiment in which the scrap melting behavior in a bath was investigated. Specifically, the effects of nature convection and driven convection on the meting process were investigated by applying a mathematical model. The results found that nature convection was formed in the vicinity of the melting interface when a scrap bar was immersed in the melting bath of hot metal. As a result, the heat transfer between bath and scrap can be enhanced by the flow at the melting interface. Also, the hot metal with high carbon content was driven to the melting interface. In turn, the melting rate was accelerated. The intensity of nature convection decreased when the initial temperature of the scrap was increased. The melting rate was remarkably increased when the driven convection was introduced to the bath. Compared to the initial temperature of 25℃ with a melting rate of 107 mm3/s, the melting rate was only 50 mm3/s when the initial temperature of scrap was 1000℃ at 5 s. In addition, when the melting was performed at 15 s, the rest volume of the scrap with the nature convection was 1054 mm3, which was 2.3 times for driven convection with the driven flow velocity of 0.15 m/s. Also, the melting rate of the scrap with the driven flow velocity of 0.15 m/s was about 1.8 times that of the nature convection at 10 s. Related Articles | Metrics

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Axial distribution characteristics of binary particles in a gas-solid fluidized bed Jun YAN Weixing JIN Yiping FAN Chenglin E Chunxi LU Fuwei SUN The Chinese Journal of Process Engineering    2023, 23 (6): 837-846.   DOI: 10.12034/j.issn.1009-606X.222204 Abstract （126）   HTML （3）    PDF （2638KB）（95）       Knowledge map    Save In order to achieve the goal of carbon peaking and carbon neutrality while taking into account the product yields of both gasoline and polyolefin, it is desirable to further optimize the polyolefin catalytic cracking technique by introducing two types of catalysts with distinct physical properties into the one reaction-regeneration system. Therefore, this work focuses on the flow and mixing characteristics of the binary particle system in a fluidized bed. The axial distribution of pressure in the binary particles fluidized bed was measured. The average solid concentration in the axial direction was investigated consequentially. The variation of the interface location between the dense phase and dilute phase zones was determined by analyzing the turning point of the axial profile of the differential pressure. An empirical coorelation was given based on the experimental results. Furthermore, the relationship of the fluidization performance of the binary particles in the fluidized bed to the gas velocity as well as the particle mixing ratio were discussed by investigating the standard deviation of pressure signal. The experimental results showed that the average particle concentration tended to decrease in the axial direction of the fluidized bed. The particle concentration decreased with an increasing of the superficial gas velocity in the dense-phase zone whereas it presented an increasing tendency in the dilute phase zone. The total average particle concentration in the dense-phase zone assumed a maximal value when the mixing ratio of big particle in the binary particles was 0.685. The interface height between the dense-phase and the dilute phase zones increased with an increasing of superficial gas velocity. It was also found that the fluidization performance and mixing degree of binary particles in the fluidized bed reached the best when 0.225≤xl≤0.479 and 0.561≤ug≤1.122 m/s. Related Articles | Metrics

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Catalytic conversion of the by-product bromoethanol in the process of CO 2 cycloaddition Ruibin GAO Lixin YI Zifeng YANG Li DONG Yifan LIU Hongfan GUO Yunong LI The Chinese Journal of Process Engineering    2023, 23 (11): 1518-1529.   DOI: 10.12034/j.issn.1009-606X.222468 Abstract （126）   HTML （0）    PDF （1824KB）（118）       Knowledge map    Save The rapid and massive accumulation of greenhouse gas CO2 in the atmosphere directly leads to global warming, ecological damage, and other environmental problems. From the perspective of renewable carbon resource utilization, CO2 is a widespread, inexpensive, and easily available C1 resource. The synthesis of ethylene carbonate employing CO2 as raw material provides a feasible industrial scheme for CO2 utilization with the atomic economy. The traditional efficient catalyst for this cycloaddition is halogen ionic liquid. However, the loss of halogen ions in the cycloaddition process leads to the additional consumption of epoxide and the generation of halogenated alcohol, thus decreasing the selectivity and yield of the main product, resulting in separation difficulty and improving equipment requirements. Therefore, it is necessary to develop an ideal catalytic system to inhibit and transform the by-product of halogenated alcohols. In this work, a series of alkalescent ionic liquids had been designed and developed to realize the in?situ conversion of bromoethanol under the condition of cycloaddition (temperature of 130℃, CO2 pressure of 3 MPa, reaction time of 3 h). The effects of different reaction conditions and different alkaline ionic liquids on the conversion of bromoethanol were investigated, including ionic liquid type, reaction temperature, different pressure environment, reaction time, etc. The reaction law of bromoethanol conversion was revealed, among which [Bu4P][HCO3] showed optimal performance. Using gas atmosphere and solvent microenvironment to regulate different reaction paths, the conversion rate of bromoethanol reached 20%~50%. After ethylene carbonate (EC) addition, the by-products with bromine-containing covalent bonds were reduced, which was more conducive to the formation of bromine ions. The conversion of halogen covalent bonds to halogen ions restored part of the catalytic activity of the cycloaddition reaction system. This was a simple versatile approach, which can realize the in?situ regulation of bromoethanol conversion pathways in the CO2 cycloaddition system, and promote the optimization of the CO2 utilization system and the circulation of halogen ions, hence possessing important scientific significance and application value. Related Articles | Metrics

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Effect of groove structure on performance of proton exchange membrane electrolyzer Yuanyue LIU Hongbo LIU Jing HE Jiaxin HAN Tao CHEN The Chinese Journal of Process Engineering    2023, 23 (5): 703-712.   DOI: 10.12034/j.issn.1009-606X.222208 Abstract （125）   HTML （11）    PDF （15018KB）（54）       Knowledge map    Save Proton exchange membrane water electrolysis (PEMEC) is a promising water electrolysis technology, but its development is limited by cost and energy consumption. In order to effectively improve the heat transfer and gas-liquid two-phase transfer ability in the anode channel of proton exchange membrane electrolysis cell and improve the electrolysis performance, the wall structure of the electrolysis cell channel was studied. Based on the electrochemical principle and the theory of mass and heat transfer, a single channel model of three-dimensional non-isothermal proton exchange membrane electrolysis cell was established. The anode channel velocity, temperature, and gas-liquid two-phase distribution of the electrolysis cell were analyzed. The effects of bionic groove and conventional groove on the heat and mass transfer and electrochemical performance of the electrolysis cell were studied. The results showed that: (1) the addition of grooves in the anode channel of the electrolytic cell can optimize the fluid velocity, energy and mass transfer performance and electrochemical performance of the electrolytic cell in varying degrees. (2) Compared with the conventional geometric grooves, the bionic curved surface grooves had more obvious optimization effects on all aspects of the performance of the electrolytic cell. Compared with triangle grooves and V-shaped grooves, the heat transfer coefficients of the anode channel with the bionic curved surface groove increased by 10.8% and 28.2%, and relative optimization rate of the mass transfer rates of liquid water and oxygen reached 47.0% and 83.3%, respectively. (3) Groove spacing affected the degree of fluid disturbance in the channel, and the number of disturbances was positively correlated with the number of grooves. When the channel length was constant, the smaller the groove spacing was, the more frequent the disturbance was, the faster the fluid velocity in the channel of the electrolytic cell was, and the overall performance of the electrolytic cell was improved. The research results can provide certain reference for the further development of proton exchange membrane electrolyzer. Related Articles | Metrics

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Large eddy simulation for single particle wake characteristics in concave-wall tangential jet Jing ZHANG Wenhao HOU Chenghao ZHOU Zhiguo TIAN Bin GONG The Chinese Journal of Process Engineering    2023, 23 (11): 1497-1505.   DOI: 10.12034/j.issn.1009-606X.223019 Abstract （124）   HTML （4）    PDF （6139KB）（197）       Knowledge map    Save Large eddy simulation was used to simulate the influence of spherical particles near the wall on fluid flow characteristics under the action of tangential jets on the concave-wall. The simulated wake vortex results were in good agreement with the experimental tracer image. The vortex structure and its evolution process of particle wake with particle diameter dp=4 mm and radius of curvature of concave wall R=200 mm were studied. The changes of velocity, vorticity, and streamline around the particle were investigated at Reynolds number Re=700~10 000. The results showed that the vorticity in the influence area of particles increased, the peak value of vorticity always appeared on the upstream surface of particles, and the recirculation zone behind the particles shrank significantly with the increase of Reynolds number. When Re=700, there was only one wake vortex behind the particle along the concave wall jet spanwise. When Re≥2000, there were two wake vortices behind particles along the concave wall jet spanwise, and the tangential velocity and vorticity of the fluid fluctuated periodically. The particle lift and resistance were monitored. There was the vortex shedding frequency at Strouhal number St=0.000 854 when Re=2000, and the peak value of the lift power spectrum occurred at St=0.001 52. The frequency peak corresponding to the boundary layer and wake instability was not found in the drag power spectrum when Re=10 000, and the peak of the lift power spectrum occurred at St=0.008 74. The particle wake had a great influence on the flow field. The analysis of the particle wake characteristics in the tangential jet on the concave wall was an in-depth study of the liquid-solid two phase separation mechanism. It provided the theory for the characteristics of single particle wake vortex in the process of heterogeneous separation of the tangential jet from concave wall. Related Articles | Metrics

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Effect of fluid-structure interaction on liquid water flow in gas diffusion layer at microscale Jiemin WANG Sai ZHANG Qingtai WANG Xianjun WANG The Chinese Journal of Process Engineering    2023, 23 (12): 1627-1636.   DOI: 10.12034/j.issn.1009-606X.223096 Abstract （119）   HTML （6）    PDF （1468KB）（59）       Knowledge map    Save This work presents a new method to reconstruct the microstructure of carbon fiber gas diffusion layer (GDL), which is used to study the effect of velocity field in rough channels on GDL seepage. The random distribution model of pore channels in the diffusion layer is obtained by using the rough element and fractal theory. By distinguishing the hydrophilicity/hydrophobicity of the channel wall, four parameters, namely, the dispersion velocity ratio, the slip enhancement coefficient, the viscosity enhancement coefficient, and the microscale effect enhancement coefficient, are obtained. With accurate internal velocity distribution reconstructed as a control factor, and the effective seepage coefficient model is obtained by combining Darcy's law. The flow process of liquid water in GDL duct is simulated, and the influence of different roughness and contact angle on liquid water transmission performance is analyzed. The results show that the distributions of dispersion velocity, viscosity and slip velocity in the diffusion layer are affected by the random distribution of channel roughness elements and the non-uniform fluid solid interaction, and the four control factors act together on the flow process of liquid water and promote the discharge of liquid water. Under the same roughness, when the contact angle is 0o~180o, the promotion of hydrophilic wall slip effect conteracting the inhibition of dispersion effect and viscosity increases, and the promotion of hydrophobic wall slip effect conteracting the inhibition of dispersion effect and viscosity decreases, and the slope of flow change curve increases significantly at first and then decreases gradually. The newly established effective seepage coefficient model of liquid water in the diffusion layer can accurately describe the flow law in GDL, which has certain guiding significance for the internal water management of GDL. Related Articles | Metrics

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Numerical simulation of frosting process of flat finned tube heat exchanger based on fluid-solid thermal coupling Qinghua CHEN Bin ZHANG Baojie ZHOU Jiadong JI Jiangang WANG Wannan WANG The Chinese Journal of Process Engineering    2023, 23 (5): 691-702.   DOI: 10.12034/j.issn.1009-606X.222186 Abstract （116）   HTML （6）    PDF （4700KB）（49）       Knowledge map    Save Plane finned tube heat exchanger was widely used in household air conditioner, environmental testing chamber, closed heat source tower, and other heat pump refrigeration systems because of its high heat transfer efficiency, low air resistance, and stable mechanical properties. It was easy to form a frost layer on the surface of flat finned tube heat exchanger working in low temperature and high humidity environment, which greatly reduced heat transfer efficiency and caused waste of energy. The study on the frosting growth on the surface of straight finned tube can provide guidance for the design of plane finned tube heat exchanger. The frosting process of plane finned tube heat exchanger is the result of the interaction of wet air, frosting layer, and heat exchanger structure. In this work, based on the fluid-solid thermal coupling calculation method, considering the changes in frost density and thermal conductivity during the frosting process, a more realistic solution domain boundary was defined, and the frosting process of 3D plane finned tube heat exchanger was numerically simulated. The average error between the simulated frost amount and the experimental value is 4.67%, which is better than the results obtained by previous numerical simulation methods. The frost growth was calculated and compared when the wet air inlet velocity was 1.0, 2.0, 3.0, and 3.7 m/s, and the relative humidity was 60%, 70%, and 80%, respectively. The results showed that the frost thickness decreased along the airflow direction, and the growth rate increased with the increase of velocity and relative humidity. The study on the heat transfer coefficient of air side showed that the higher the relative humidity of air was, the higher the heat transfer coefficient was at the beginning of frosting. In the late frosting period, the greater the relative humidity of the air was, the smaller the heat transfer coefficient was. Related Articles | Metrics

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Thermodynamic analysis and properties of Fe-V alloy prepared by direct reduction of vanadium slag Weibin WANG Ziyang ZHANG Haitao LIU Wei WANG The Chinese Journal of Process Engineering    2023, 23 (5): 763-770.   DOI: 10.12034/j.issn.1009-606X.222223 Abstract （115）   HTML （2）    PDF （34754KB）（37）       Knowledge map    Save Vanadium slag is considered to be a secondary resource of polymetallic symbiosis for the reason that it contains various metal elements such as iron, vanadium, chromium, etc. Currently, a variety of technologies for extracting vanadium and chromium from vanadium slag have been explored in detail. While the treatment of iron in vanadium slag is reported rarely. What's more, a great deal of iron elements cannot be effectively recovered and enter the tailings in the existing research, which leads to the waste of iron resources. For achieving the synergistic recycle of vanadium and iron in vanadium slag, Fe-V alloy was prepared successfully by high-temperature carbothermal reduction smelting with vanadium slag and high-iron red mud. Thermodynamic analysis of the whole reduction system is carried out by using thermodynamic information such as oxygen potential diagram and phase diagram. The result indicates that the oxides of iron and vanadium can be deoxidized easily at high temperature and developed a completely miscible alloy in solid and liquid phases. Therefore, it is feasible to prepare Fe-V alloy in this way. Experimental studies have been made in this work systematically and comprehensively for the effect of raw material ratio on metal recovery rate as well as the impact of adding Na2CO3 and coke on the microstructure and performance of the alloy. The results indicate that the addition of high-iron red mud can improve the basicity of the mixture, and Na2CO3 can improve the reduction conditions of Fe2SiO4 and FeAl2O4, which is beneficial to improving the reduction efficiency of the reaction system. When the addition amounts of Na2CO3 and coke are 8wt% and 30wt%, respectively, the recovery rate of Fe and V in the raw material is the highest. Furthermore, V can promote the pearlite transformation during the solidification, which improves the mechanical properties of the alloy. This work is able to provide a new and reasonable pathway for high value utilization of vanadium slag. Related Articles | Metrics

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Influence of structure of swirlers on fluid field characteristics of main absorption tower Zhanyu YANG Qiling YIN Tuanliang WANG Yuge LI Wenming SONG Yufu ZHANG Yuan YAN Liping WEI The Chinese Journal of Process Engineering    2023, 23 (10): 1401-1410.   DOI: 10.12034/j.issn.1009-606X.222384 Abstract （114）   HTML （2）    PDF （17878KB）（75）       Knowledge map    Save The main absorption tower of natural gas with high hydrogen sulfur content purification needs regular welding repair due to corrosion. Before and after repair, the internal combustion integral heat treatment technology can be used to perform hydrogen-eliminating treatment and eliminate stress. The arrangement of swirlers has an important impact on air distribution and flame control during the heat treatment. In this work, the fluid field characteristics of two-stage swirler, single-stage swirler I and II in the absorption tower are simulated, respectively. The results show that there is no obvious recirculation zone above the two-stage swirler and the velocity distribution is uniform. A large tangential velocity is generated above the inner and outer swirler blades. The maximum tangential velocity is 8.33 m/s when the inlet velocity is 9.8 m/s, followed by single-stage swirler II and single-stage swirler I, 4.5 m/s and 3.12 m/s, respectively. The pressure drop in the tower corresponding to the two-stage swirler has the smallest change. These prove that the two-stage swirler can effectively generate low resistance swirling flow field. The proportion of the streamline at the bottom of the tower corresponding to the two-stage swirler changes steadily with the gas mass flow rate, and is kept at about 14%, which is consistent with the percentage of the tower bottom wall in the total surface area of the tower body. It can ensure that enough gas media return to the tower bottom and promote gas convection. The 90% residence time of two-stage swirler increases linearly with the increase of gas mass flow rate. In general, the swirling effect of the two-stage swirler is better than that of the other two swirlers, and this study provides a reference for the optimization design of swirl device of internal combustion integral heat treatment process. Related Articles | Metrics

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Study on aluminum anode with different Ti addition for kW-grade aluminum-air batteries Cong XU Xinyue FANG Min KONG Ruizhi WANG Jun ZHANG Guangxi LU Junhua HU Shaokang GUAN The Chinese Journal of Process Engineering    2023, 23 (8): 1131-1136.   DOI: 10.12034/j.issn.1009-606X.223107 Abstract （113）   HTML （5）    PDF （27370KB）（50）       Knowledge map    Save With the development of science and technology, modern industry and social development rely more and more on electric energy, advanced and efficient energy conversion technology is the key to the development, of new high-power fuel batteries (such as aluminum-air batteries) because of its high energy density (theoretical energy density 8100 Wh/kg), abundant storage capacity, low production cost, environmental protection, and non-toxic advantages and so on favored by many scholars. However, there are some problems against the application of aluminum anodes, such as high overpotential caused by the attached passivation layer on the surface and high self-corrosion rate in alkaline electrolytes. To address these challenges, many researchers are committed to improving anode performance through microalloying. In this work, the effects of different Ti contents (0.03wt%, 0.05wt%, 0.08wt%, and 0.10wt%) on the microstructure, corrosion behavior, electrochemical behavior, and discharge behavior of Al-Mg-In anode materials for kilowatt-class aluminum-air batteries were investigated systematically. The results show that with the increase of Ti content, the fibrous grains in the Al-Mg-In anode gradually refine, the grain organization gradually becomes uniform, and the increase of the number of grain boundaries can provide more reaction area for the air batteries, and the discharge activity of the anode material will increase with more discharge reaction channels, which will help to increase the working voltage of the aluminum anode. However, when the Ti addition exceeds 0.05wt%, the number of second phase particles in the Al-Mg-In anode sheet will increase, and a "primary battery" will be formed between the second phase and the substrate, which will accelerate the corrosion of the alloy and the local dissolution of grain boundaries, resulting in the decrease of corrosion resistance and discharge performance of the alloy. Therefore, the Al-Mg-In alloy with 0.05wt% Ti has the best corrosion resistance and battery discharge performance, indicating that the appropriate amount of Ti can optimize the performance of aluminum-air batteries. Related Articles | Metrics

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A review of heat storage performance improvement and power generation application of salt gradient solar pond Hao MA Hua WANG The Chinese Journal of Process Engineering    2023, 23 (7): 972-986.   DOI: 10.12034/j.issn.1009-606X.223111 Abstract （113）   HTML （3）    PDF （1859KB）（66）       Knowledge map    Save The salt gradient solar pond is a kind of large area of saline water that can simultaneously absorb and store solar energy in the thermal energy. It has attracted widespread attention from researchers due to its advantages such as long-term heat storage, large heat storage capacity, and the ability to provide a stable and clean low-temperature heat source. Traditional salt gradient solar pond stores thermal energy by sensible heat of the saline water, and the thermal storage density is limited. The application of salt gradient salt gradient solar ponds is very extensive. It can directly utilize the heat of salt gradient solar pond and provide a stable low-temperature heat source for industry, agriculture, and daily life. The thermal energy of the salt gradient solar pond can also be used for thermoelectric conversion to provide electricity for various fields. This work first analyzes the key factors affecting the heat storage performance of salt gradient solar pond, the methods to improve the thermal storage performance of salt gradient solar pond, compares and analyzes various heat extraction methods of salt gradient solar pond. Then, the application of salt gradient solar pond in the field of power generation at domestic and abroad is introduced, and the research of salt gradient solar pond power generation technology is summarized and analyzed, aims to provide references for the construction, operation, maintenance of salt gradient solar pond and also the application in power generation. Related Articles | Metrics