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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 （613）   HTML （33）    PDF （3494KB）（511）       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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Review on progress of 5 V spinel Co-free LiNi 0.5Mn 1.5O 4 cathode material Jia JIN Jinping WEI Zhen ZHOU The Chinese Journal of Process Engineering    2022, 22 (4): 421-437.   DOI: 10.12034/j.issn.1009-606X.221115 Abstract （559）      PDF （11182KB）（434）       Knowledge map    Save As a candidate cathode material for next-generation Li-ion batteries or solid state batteries, the spinel LiNi0.5Mn1.5O4 is appealing researchers' interest. The 5 V spinel material of LiNi0.5Mn1.5O4 had ordered and disordered phases, and crystal structure, synthetic method and electrochemical reaction mechanism of which were discussed. Also, its electronic conductivity and lithium ion diffusion coefficient were highlighted compared with other cathode materials. The advantages of LiNi0.5Mn1.5O4, such as high discharge plateau, good rate performance, high thermal stability, abundant manganese resources and low cost, were introduced. Then technical obstacles hindering the industrialization of LiNi0.5Mn1.5O4 were discussed, including poor cycle performance at high temperature, low cycling coulombic efficiency, metal dissolution and phase transition, electrolyte decomposition at high voltages, gas generation in full cells. The main reason negatively affected the electrochemical performance of Li-ion batteries was electrochemical oxidation of carbonate esters at the LiNi0.5Mn1.5O4/electrolyte interface which resulted in Ni/Mn dissolution, crystal structural transformation and surface film formation, and eventually led to lower electronic conductivity and Li+ transport kinetics in Li-ion batteries. Some solution ideas were summarized at the material level, such as microscopic morphology control, new binder slurry strategy, doping, coating, high voltage matching electrolytes, synthetic control, and these material solution ideas should be coordinated with full cell design. In addition, this review speculated a few possible application scenarios on basis of its merits, for instance, start-and-stop power supply, low-temperature application, power tools and so on. Commercialization of LiNi0.5Mn1.5O4 relies on elaborate construction design at the battery level beside the materials design. More wide and thorough application research needs to be done to push the industrialization of LiNi0.5Mn1.5O4. Related Articles | Metrics

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CO2 methanation: recent advances in catalyst development and reaction mechanistic study Junbo TIAN Fangna GU Fabing SU Zhanguo ZHANG Guangwen XU The Chinese Journal of Process Engineering    2023, 23 (3): 375-395.   DOI: 10.12034/j.issn.1009-606X.222027 Abstract （653）   HTML （28）    PDF （12772KB）（349）       Knowledge map    Save Choosing a suitable approach for CO2 utilization is crucial to achieving carbon neutrality and carbon peak goals as early as possible. Synthesis of synthetic natural gas (SNG) by methanation of CO2 using hydrogen produced from renewable energy is widely regarded as an efficient and promising carbon capture and utilization technology, which is expected to realize carbon recycling. Considering the importance of CO2 methanation, we provide a systematic review of the latest studies. Firstly, the effect of different reaction conditions on CO2 methanation is introduced from the perspective of thermodynamics. Secondly, the research progress of CO2 methanation catalysts is reviewed from four aspects: active metal, support, preparation method, and assistive technology. In detail, the active components are classified into cheap metal-based (Ni, Fe, Co, and Mo) and noble metal-based (Ru, Rh, Pt, and Pd) materials, and the supports are divided into the conventional oxides (Al2O3, SiO2, TiO2, ZrO2, and CeO2) and the supports with novel structures (e.g., metal-organic frameworks and carbon-based materials), which are all discussed and evaluated in depth. The preparation methods of catalyst are classified as the conventional ones (such as impregnation, coprecipitation, hydrothermal, sol-gel, and solid-phase synthesis) and unconventional ones. The latter includes three technologies such as ultrasound, microwave, and plasma, which can speed up the synthesis and reaction process and facilitate the high dispersion of the active components on the supports. Subsequently, two reaction mechanisms in CO2 methanation (the formate and CO pathways) are discussed. The specific reaction pathway for CO2 methanation is related to the properties of the catalyst surface (e.g., hydroxyl abundance, adsorbed O2- sites) and the reaction conditions (e.g., reaction temperature and pressure). Finally, current research challenges are put forward, and the prospects for future research in this area are made. Related Articles | Metrics

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Research progress on synthesis and industrialization of fatty primary amines Jiasheng PAN Yaofeng WANG Shuangshuang MA Rui SUN Yuting TONG Qida DING Rui ZHANG The Chinese Journal of Process Engineering    2021, 21 (8): 905-917.   DOI: 10.12034/j.issn.1009-606X.220235 Abstract （717）   HTML （16）    PDF （1360KB）（337）       Knowledge map    Save Organic amines have a wide range of applications in chemical, pharmaceutical, life science and other fields. They can be used as raw materials for dyes, daily necessities, antibiotics, alkaloids, and clinical medicines. Among different amine compounds, primary amine is the most basic structural unit. Its application is also the most widely used in amine compounds. With the rapid development of economic and social as well as the improvement of people's quality of life, the market demand for primary amines, especially fatty primary amines, is increasing day by day. The synthesis and industrial preparation of fatty primary amines has become an important field. After decades of development, though the production technology of fatty primary amines has achieved great results, there are still some problems such as harsh reaction conditions, insufficient catalyst performance, serious pollution, complicated processes, etc. This work takes the industrial production and hot preparation methods of fatty primary amines as the research object, summarizes the process of preparing fatty primary amines in industry (including alkylation of organic halides with ammonia, reductive amination of alcohol, hydrogenation reduction of nitrile, direct amination of olefin, amination of carboxylic acid, etc.) and illustrates the practical application of each preparation method in industry production. It also analyzes and compares the advantages and disadvantages of each production method. Inferior, the current research hotspot-the method of preparing fatty primary amines by reductive amination of carbonyl compounds is described, and the potential and challenges of the preparation method in future industrial applications are pointed out. 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 （322）   HTML （90）    PDF （47402KB）（336）       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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A review on the approaches to the production of vanadium metal Weiliang LU Ying ZHANG Pei SUN Shili ZHENG Shan QIAO Yang ZHANG Ping LI Yi ZHANG The Chinese Journal of Process Engineering    2021, 21 (10): 1117-1131.   DOI: 10.12034/j.issn.1009-606X.220294 Abstract （1416）      PDF （4507KB）（331）       Knowledge map    Save Vanadium metal, known as "industrial monosodium glutamate", is widely used in the fields of metallurgy, chemical engineering, aviation, energy, atomic energy, etc. Vanadium belongs to the rare reactive metals with a high melting point, and its production is difficult and costly. Currently, the main route for the production of high-purity V is the combination of the aluminothermic reduction of vanadium oxide and the vacuum melting purification of the crude V; however, this route is energy-intensive and low-yield. In order to reduce the production cost of metallic vanadium, many approaches to the production of crude vanadium have been proposed based on the thermodynamic stability of vanadium oxides and vanadium chlorides, including calciothermic reduction, magnesiothermic reduction, vacuum carbothermic reduction, silicothermic reduction, carbothermic reduction-nitridation-nitride thermal decomposition, molten salt electrolytic deoxidation, etc. The developed refining approaches includes molten salt electrolytic refining, iodide thermal decomposition, solid-state electro-transport purification, etc. This paper reviews the above methods comprehensively in terms of principles, technical features, effectiveness, and drawbacks. It is expected that this review will provide important guidance for the development and upgrading of the approaches for the production of high-purity V metal. It is believed that the application of vanadium will continue to expand with the achievement of high-end materials, which no doubt promotes the development of high-purity metallic vanadium production industry. Related Articles | Metrics

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Preparation and electrochemical performance investigation of molybdenum dioxide nanorods Zengli GAO Shouzhi YI Haiyan TANG Hongbin XU The Chinese Journal of Process Engineering    2021, 21 (11): 1338-1345.   DOI: 10.12034/j.issn.1009-606X.220355 Abstract （462）      PDF （986KB）（315）       Knowledge map    Save With high conductivity, high melting point and large specific capacity, molybdenum dioxide (MoO2) nanorods have a wide application prospect in the field of electrode materials for supercapacitors. Although there are many methods to prepare MoO2 nanorods, most of them have disadvantages of a complicated process, low yield, high production cost and easy to introduce impurities. Moreover, the prepared MoO2 products have the characteristics of non-uniform morphology, poor dispersibility and inferior electrochemical performances. In this work, the precursor of peroxymolybdic acid prepared by hydrogen peroxide and molybdenum powder was used as the source of molybdenum, and PEG (8000) was used as the template. The molybdenum-containing hybrid with a band structure was prepared by mixing the precursor and template with stirring and thermal insulation. The nano-rod-shaped MoO2 was prepared through a two-stage hydrometallurgical process using the hybrid compound as raw material. X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), X-ray energy spectrometer (EDS) and scanning electron microscope (SEM) were used to analyze the phase, surface composition and morphology of the obtained MoO2 nanorods. The electrochemical capacitance behavior of MoO2 nanorods was studied using a three-electrode system and two-electrode system, and the performance of MoO2 nanorods as electrode assembly capacitors was also investigated. The results showed that the prepared MoO2 had a rod-like structure with 500 to 800 nm in length and with 100 to 200 nm in width. The MoO2 had uniform morphology and size with good dispersion and high purity. The specific capacitance of MoO2 nanorods was 366.7 F/g for the three-electrode system at the current density of 1 A/g, and the specific capacitance for the two-electrode system was 290.4 F/g, and the capacitance retention rate was higher than 72% after 2000 cycles of charging and discharging at 5 A/g current density, both showing the good electrochemical performance of MoO2 nanorods. The research results of this study can provide a new method for the preparation of other nano metal oxides. Related Articles | Metrics

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Comparative study of fluid residence time distribution and flow pattern in baffle equipment Zhangfan GAO Muyi FAN Shaobei LIU Xiong ZOU Weixing HUANG The Chinese Journal of Process Engineering    2021, 21 (11): 1269-1276.   DOI: 10.12034/j.issn.1009-606X.220363 Abstract （386）      PDF （1447KB）（307）       Knowledge map    Save The flow pattern in the equipment can be the main performance index for its internal structure. Innovation of process equipment is to optimize its internal structure for desired flow pattern. Numerical simulation, as a primary research approach of fluid flow pattern, is not easy and economical to perform in large-scale or complex equipment, but the residence time distribution (RTD) experiment has the advantages of simplicity and convenience. In order to estimate the flow pattern with RTD experiments, taking the typical baffle structure as an example, several groups of structures were designed to compare and analyze the residence time distribution and the flow patterns corresponding to the structures, which can provide clues for short circuits judgement and determination of reasonable structures. The results showed that the short circuit and dead zone in the equipment were relativistic. The peak time and tailing of the RTD density function curve can be used to judge the short circuit and dead zone in the equipment. This conclusion can provide a theoretical basis for equipment design. The number of tanks in the multi-tank series model and the peak time and variance of the RTD curve were used to analyze the influence of flow rate, baffle gap area and plate spacing on the fluid flow pattern in the equipment. With the study of the pressure drop and the comprehensive consideration of the energy consumption and performance of the equipment, the most suitable tanks number, peak time and variance were put forward based on RTD experiments to determine the reasonable structure of the equipment, which provided a reference for the structural design of industrial baffle equipment. Related Articles | Metrics

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Numerical simulation of hollow catalyst with pores in gas-solid reaction system Qiuying WU, Lingkai KONG, Ji XU, Wei GE, Shaojun YUAN The Chinese Journal of Process Engineering    2021, 21 (7): 774-785.   DOI: 10.12034/j.issn.1009-606X.220229 Abstract （403）   HTML （14）    PDF （1654KB）（283）       Knowledge map    Save In the gas-solid flow, fluid and particle usually aggregate to form dense-phase and dilute-phase respectively, resulting in unbalanced mass transfer and reaction rates between the dense- and dilute-phase. The unbalance of dilute- and dense-phase reduces the overall efficiency of the reactor. To solve this problem, a hollow catalyst particle with pores structure is designed. It is aimed to enhance the overall efficiency of fluidized reactors by improving the mass transfer rate between the dense- and dilute-phase. Dense- and dilute-phase are widely distributed during fluidization processes, which can be respectively described by the cluster system and single particle system. In these two phases, the flow, reaction process and mass transfer process of hollow porous particles are studied by numerical simulation, and compared with the solid spherical particle system at the same fluidization condition. Then, the frequency of particle clusters formation and breakage is studied under various fluidization conditions. The time scale is analyzed to measure the possibility of gas transport in the fluidization process. It is found that the time-scales of the mass transfer, the reaction, and the movements of particles between the dilute- and dense-phase could be at the same order for some fluidization conditions. Thus, hollow porous catalyst particle can store the reacting material in the dilute-phase efficiently. When moving to the dense phase, the particle would release the reacting material to provide additional material for the dense-phase reaction. When the reaction is faster than the mass transfer, the overall reaction rate of the hollow porous catalyst system is 26.92%~29.55% higher than that of the solid spherical catalyst system at the studied conditions. It could be predicted that this hollow porous catalyst would be capable to improve the overall reaction efficiency of large gas-solid fluidized bed reactors due to wider distributions of the dilute- and dense-phase. Table and Figures | Reference | 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 （328）   HTML （15）    PDF （1140KB）（269）       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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Impurity removal and hydrothermal heterogeneous cryogenic rapid oxidation of semi-dry desulfurization ash from iron ore sintering flue gas Rufei WEI Yulong ZHU Di ZHOU Yifan WANG Hongming LONG The Chinese Journal of Process Engineering    2021, 21 (8): 951-958.   DOI: 10.12034/j.issn.1009-606X.220223 Abstract （367）   HTML （11）    PDF （1803KB）（267）       Knowledge map    Save The semi-dry desulfurization ash of iron ore sintering flue gas cannot be effectively utilized because it contains a lot of unstable calcium sulfite. Oxidation modification of desulfurization ash is an important means to realize its large-scale or high-value utilization. The results show that the calcium carbonate in the desulfurization ash is the main factor limiting its oxidation modification. Calcium carbonate and calcium sulfite cover each other, which reduces the specific surface area of calcium sulfite oxidation reaction and limits its oxidation rate. Two weak acids, L(+)-ascorbic acid and glacial acetic acid, were used to remove calcium carbonate. Glacial acetic acid with a concentration of 0.4 g/g could increase the content of calcium sulfite to 81.17% with the maximum increase of 69.71%. The effect of different factors on the oxidation rate of calcium sulfite in desulfurization ash was studied by subcritical hydrothermal heterogeneous oxidation method. The results showed that the oxidation rate of calcium sulfite was significantly increased after removing impurities. The oxidation rate of calcium sulfite can be increased by increasing the initial pressure, the reaction temperature and time, and reducing the solid-liquid ratio. When the reaction temperature was 140℃, the reaction time was 30 min, the initial pressure was 2 MPa, the initial solid-liquid ratio was 1:30 and the rotating speed was 300 r/min, the oxidation rate of calcium sulfite was 98.72%, while the oxidation rate of desulfurized ash without impurity removal was only 78.77% at 180℃(other conditions were the same). In this work, the desulfurization ash was oxidized rapidly at low temperature. From the micro morphology point of view, compared with the desulfurized ash without impurity removal, the calcium sulfite after impurity removal was easier to grow along the radial direction, which had preliminary conditions for the preparation of calcium sulfate whiskers with a large aspect ratio, which was of great significance for the preparation of calcium sulfate whiskers. Related Articles | Metrics

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Research review in regulating interfacial interaction on MOF-based mixed matrix membranes for gas separation Lili GONG Ju BAI Can WANG Wei LAI Linglong SHAN Shuangjiang LUO Zhichang LIU The Chinese Journal of Process Engineering    2023, 23 (4): 489-500.   DOI: 10.12034/j.issn.1009-606X.223054 Abstract （281）   HTML （21）    PDF （7406KB）（252）       Knowledge map    Save Mixed matrix membranes (MMMs) have attracted substantial attention for gas separation, combining the advantages of organic polymers and inorganic fillers, which are expected to solve the Trade-off effect. Metal organic frameworks (MOF), as a kind of innovative filler, provided promising development opportunities for MMMs, thanks to high surface area and porosity, adjustable pores, and low density, etc. These unique physical and chemical properties promoted the application in gas adsorption, separation, and storage. MOF is regarded as good compatibility with the polymer matrix because the organic linkers in MOF are more similar to the organic chain of the polymer compared with traditional inorganic materials (molecular sieve or metal oxide, etc.). Gas separation performance is improved by incorporating MOF into the polymer matrix, which is expected to balance the Trade-off effect. However, the separation performance of MMMs is not simply the sum of the two phases and is far below the predicted theoretical value by the material simulation in most cases. One of the key reasons for these non-ideal morphologies resulting from poor interfacial compatibility, including the non-selective interfacial voids, polymer rigidified, and pore blockage, which reduce the separation performance of MMMs. Therefore, good interfacial compatibility plays a key role in MMMs. Constructing effective interface interactions is a feasible strategy to improve interface compatibility. Thus, in this review, a comprehensive overview of the main technical challenges in developing MOF-based MMMs and a detailed description of the interface issues are provided. And constructing different interface interactions, including hydrogen bonds, covalent bonds, coordination bonds and others, has been expounded through various methods and strategies in the last five years. Finally, it aims to summarize the positive effects on the properties of MMMs through effective and strong interface interactions, guiding the future development of MOF-based MMMs. Related Articles | Metrics

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Simulation and experimental study of fluid flow in the bed of columnar particles in a tubular fixed bed reactor Zirui ZHU Xuedong LIU Liangxiong JIANG Yutong GU Tao PENG Junjie YIN Meihua LIU Wei JIANG The Chinese Journal of Process Engineering    2021, 21 (9): 1022-1032.   DOI: 10.12034/j.issn.1009-606X.220288 Abstract （416）      PDF （4564KB）（238）       Knowledge map    Save In view of the large number and large scale of tube bundles in the tubular fixed bed reactor, a single tube bundle was selected as the characteristic structure of the study. For the tube bundles filled with columnar particles of different diameters, the method of program coordinate positioning was adopted and the physical model of the columnar particle bed was established. DEM and CFD numerical simulation methods were used to explore the influence of the ratio of the inner diameter of the reaction tube to the equivalent surface area spherical equivalent diameter of columnar particles (Di/dp) on the fluid flow in the cylindrical particle bed. A single-tube fixed-bed reactor test device was established, and the differential pressure test method was used for experimental research. The results showed that when Di/dp increased from 5.37 to 12.75, the porosity of the bed and the uniformity of fluid distribution were improved, and the influence of the wall effect was weakened from the center of the bed to the tube wall. Based on the numerical simulation and experimental results, the bed pressure drop Ergun formula was corrected with constant coefficients for the columnar particle bed with Di/dp=12.75. The CFD simulation calculation results were in good agreement with the fitting formula. The research results provided guidance value for the design and application of fixed bed reactor. Related Articles | Metrics

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Research progress on kinetic models of ethane pyrolysis Juan WANG, Haohan XU, Kai XIE, Haiyan YU The Chinese Journal of Process Engineering    2021, 21 (7): 752-761.   DOI: 10.12034/j.issn.1009-606X.220208 Abstract （545）   HTML （10）    PDF （904KB）（236）       Knowledge map    Save As the basic raw material for the production of various petrochemical products, ethylene plays an important role in the petrochemical field. With the global energy structure adjustment brought about by the shale gas revolution, ethane has gradually become the preferred raw material for ethylene production. Ethane pyrolysis technology has the advantages of high yield, low cost and low energy consumption. As the core content of cracking furnace mathematical model, the establishment of reaction kinetics model is the basis of simulation, control and optimization of cracking process. Therefore, under the current energy environment, it is of great significance for the development of domestic ethylene industry to study and summarize the kinetic model of ethane pyrolysis. In this work, the research status of ethane cracking process, pyrolysis reaction kinetic model and coking reaction kinetic model are summarized. The kinetic models of pyrolysis reaction are divided into empirical model, mechanism model and molecular reaction dynamics model. The kinetic models of coking reaction are divided into catalytic coking and free radical coking. This work not only introduces the basic models, but also compares and summarizes the process of gradual optimization of the models. In addition, this work puts forward new prospects for the future research direction. In the future, the combinations of the empirical model with the automatic control technology of cracking furnace and the reaction kinetics model with CFD technology are of great necessity. The co-cracking process of ethane and propane and optimization the product distribution needs to be further researched. The establishment of reaction kinetics model which can accurately predict the coking process need to be explored. In conclusion, ethane pyrolysis not only brings opportunities for industrial production, but also provides a new direction for researchers. Table and Figures | Reference | Related Articles | Metrics

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Research progress and application of heat transfer enhancement of twisted oval tubes Xiuzhen LI Yingying TAN Junfei YUAN Zhanwei WANG Lin WANG The Chinese Journal of Process Engineering    2022, 22 (5): 561-572.   DOI: 10.12034/j.issn.1009-606X.221153 Abstract （407）      PDF （6683KB）（227）       Knowledge map    Save The twisted oval tube has simple structure, excellent heat transfer enhancement and anti-fouling performance, and has become one of the research hotspots in the field of passive heat transfer enhancement. In recent years, researchers have carried out a lot of research on the heat transfer performance of twisted elliptical tubes (bundles) through experiments and numerical simulations. The mechanism of heat transfer enhancement is explained.Although there are reviews on the technology of twisted oval tube exchangers, there are deficiencies in the induction of the heat transfer enhancement characteristics of twisted oval tubes and the analysis of the research clues of the engineering application. This review focuses on the internal and external heat transfer and flow resistance performance of the twisted oval tube, and summarizes the influence of the structure of the twisted oval tube (bundle), working fluid and flow state on the heat transfer performance and flow resistance characteristics. The review also reviews the engineering application cases of twisted oval tube heat exchangers, and outlines the contents to be perfected in the researches on twisted oval tubes, and prospects the development trend of the research on heat transfer intensification of twisted oval tubes. This review is expected to provide guidance and reference for deepening the theoretical research and engineering practice of twisted oval tubes. Related Articles | Metrics

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Leaching of valuable metals from nickel sulfide ores by mechanical activation Xiaohong ZHENG Weiguang LÜ Hongbin CAO Nan CAI Jin ZHAN Qingchun LI Fei KANG Zhi SUN The Chinese Journal of Process Engineering    2021, 21 (9): 1064-1073.   DOI: 10.12034/j.issn.1009-606X.220146 Abstract （242）      PDF （3050KB）（226）       Knowledge map    Save The demand for nickel resources has increased significantly in recent years due to the large-scale application of high-nickel ternary lithium batteries in the field of new energy electric vehicles. To alleviate the shortage of nickel resources in China, the nickel extraction from nickel-containing minerals has received widely attention. As an important nickel-containing minerals, the composition of nickel sulfide ore is complex and it is difficult to be leaching under atmospheric conditions. Therefore, green, high efficient, and low-cost technologies for extracting nickel from nickel sulfide ore resources have attracted much attention. In this work, the mechanical activation was introduced to increase the reactivity of nickel sulfide ore, then Na2S2O8 was used to leaching activated nickel sulfide ore under atmospheric conditions. Various conditions including rotation speed, ball-to-material ratio and ball milling time as well as the acid concentration, oxidation concentration, leaching time, liquid-to-solid ratio, stirring rate and temperature in the leaching process were optimized and the mechanism was further discussed. It was found that the mechanical activation process reduced the particle size and increased the degree of amorphization of nickel sulfide ore resulting in an increase in its reactivity, and the leaching process converted part of the S2- to sulfur by Na2S2O8 reducing the release of harmful gas H2S during the reaction. At the optimal conditions (rotation speed of 613 r/min, ball-to-material ratio of 20:1, ball milling time of 120 min, acid concentration of 2 mol/L, Na2S2O8 concentration of 0.42 mol/L, leaching time of 60 min, liquid-to-solid ratio of 5:1, stirring rate of 400 r/min and temperature of 80℃), leaching rate of Ni, Co, Cu and Fe were 98.9%, 97.7%, 98.2% and 98.7%, respectively, while the content of Ni, Co and Cu in residues were 0.45%, 0.03% and 0.14%, respectively. With this research, it was expected to provide theoretical and technical support for the efficient extraction of valuable metals from nickel sulfide ores. Related Articles | Metrics

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Progress in boron recovery from salt lake brines by solvent extraction Zhenya XU Hui SU Jian ZHANG Wensen LIU Zhaowu ZHU Jinggang WANG The Chinese Journal of Process Engineering    2021, 21 (11): 1259-1268.   DOI: 10.12034/j.issn.1009-606X.220366 Abstract （451）      PDF （790KB）（226）       Knowledge map    Save In this work, four types of solvent systems for boron recovery from salt lake brines including aliphatic alcohol (monohydric alcohol, diol, mixed alcohol), aromatic polyhydroxy compound, amine compound containing hydroxyl group and ionic liquid were systematically reviewed, focusing on the recent research and application progress. The extraction mechanism of boron by various extractant systems were highly summarized to clearly explain the effect of extractant structures on the extraction performance. The extraction performance of different extractants and the influence of coexisting ions on the extraction process were analyzed, and the future research and development direction of boron extraction from salt lake brines were discussed. The monohydric alcohol was suitable for extracting boric acid under the conditions of high salting-out and acidity. But it also had serious disadvantages including low extraction rate, and severe equipment corrosion. Diol had higher extraction efficiency than monohydric alcohol, but it was difficult to realize large-scale industrial production due to high viscosity, high solution loss and difficult stripping from the loaded organic phase. Therefore, the recycling performance of diol extractant was relatively poor. The mixed alcohol system was suitable for industrial application of boron extraction from acid salt lake brines because of its synergistic extraction effect and low cost, and can also reduce viscosity and solution loss. Other systems, such as hydroxyl-containing aromatic and amine compounds, had good extraction effects on boron from alkaline salt lake brines, but they were generally expensive and difficult for industrial application. Ionic liquid can be used for boron extraction and diluent because of its advantages such as low volatility, good chemical stability and designable structure, which had a certain application prospect. Related Articles | Metrics

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Progress on biomethane production via biogas cleaning and upgrading Gama YANG Tingzhen MU Maohua YANG Delu MIAO Xuhao ZHAO Bin TANG Jianmin XING The Chinese Journal of Process Engineering    2021, 21 (6): 617-628.   DOI: 10.12034/j.issn.1009-606X.220154 Abstract （474）      PDF （556KB）（223）       Knowledge map    Save Biomethane is a kind of renewable fuel produced after the biogas is purified by desulfurization, decarbonization and dehydration. Its composition and calorific value are almost same as natural gas which means biomethane is a promising renewable energy to be used as vehicle fuel or injected to the natural gas grid. To enable the efficient use of biomethane in these applications the biogas must be cleaned and upgraded. Removal of H2S and CO2 are necessary processes for the commercial utilization of biogas and a number of techniques for transformation of biogas to biomethane have been developed. In this review, the main desulfurization and decarbonization technologies for the production of biomethane were systematically reviewed with their upgrading efficiency, methane (CH4) loss, energy requirement, environmental effect, development and industrialization. The technologies for the removal of H2S discussed in this work including absorption (physical and chemical), adsorption and biodesulfurization. And the technologies for the removal of CO2 including absorption (physical and chemical), pressure swing adsorption (PSA), membrane separation, cryogenic separation and the emerging biological methanation processes were discussed. Process flow and mechanism of each technology, as well as commercialization examples were introduced in detail with emphasizing their critical points and analyzing their advantages and deficiencies. Particularly, the review emphasized that biodesulfurization and biological methanation possess significant advantages over conventional physical/chemical technologies for biogas upgrading. Main advantages were that biotechnologies operated at normal temperatures and pressures, without the use of toxic complex chemicals, especially the biological removal of H2S in biogas had undergone a rapid development over the past 20 years and was nowadays commercially available and implemented in full scale facilities. The current challenges and future perspectives of biogas desulfurization and decarbonization processes were also discussed. Finally, the aim of the review was to provide process references for the research and industrial development of biomethane. 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 （231）   HTML （7）    PDF （4779KB）（223）       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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Study on adsorptive separation property of CaY zeolite for ethylene glycol and 1,2-butanediol Fan YI Peng HE Junya CAO Yan CAO Liguo WANG Jiaqiang CHEN Huiquan LI The Chinese Journal of Process Engineering    2022, 22 (4): 448-457.   DOI: 10.12034/j.issn.1009-606X.221007 Abstract （323）      PDF （2418KB）（222）       Knowledge map    Save Ethylene glycol is an important petrochemical basic organic raw material, mainly used in the production of polyester, antifreeze, membrane, etc. China has abundant coal resources, which makes coal to ethylene glycol technology increasingly valued. As more and more coal to ethylene glycol plants is successfully running in China, the separation problem of ethylene glycol and 1,2-butanediol is urgently waiting to be solved. Selective adsorption is considered the most promising method because of its environmentally friendly characteristic and low cost. In this work, a fixed-bed column was used to separate ethylene glycol and 1,2-butanediol by using CaY zeolite as an absorbent, n-propanol was selected as the best eluent. In the fixed-bed column experiments, breakthrough curves were obtained and the dynamic adsorption characteristics were analyzed through breakthrough curves. The effect of operational conditions, such as flow rate and operating temperature were examined. The adsorption selectivity of ethylene glycol to 1,2-butanediol reached 1.90 at the temperature of 298 K and the flow rate of 0.8 mL/min. It can be found that the adsorption capacity of EG was much higher than 1,2-butanediol. The experiment results indicated that the breakthrough time and adsorption amount both decreased with increase of the flow rate and operating temperature. Modified Dose-Response models gave satisfactory fits to the experimental data of breakthrough curves in a fixed-bed column. At last, the adsorption sites of ethylene glycol and 1,2-butanediol were determined by Grand Canonical Monte Carlo (GCMC) simulation. It was found that the adsorption sites of ethylene and 1,2-butanediol almost overlapped, which meant ethylene glycol and 1,2-butanediol were competitive adsorptions in CaY zeolite. Moreover, the adsorption capacity of ethylene glycol was greater than 1,2-butanediol, which was consistent with the experiment result. The simulation result provided microscopic theoretical support for the experimental results. From these studies, CaY zeolite had the potential to be used as an effective absorbent for the adsorption and separation of ethylene and 1,2-butanediol. Related Articles | Metrics

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Multi-scale CFD simulation of fluidization characteristics in a methanol-to-olefin fluidized bed Kun HONG Manqian CAO Wenxuan WANG Ya'nan GAO The Chinese Journal of Process Engineering    2021, 21 (9): 1012-1022.   DOI: 10.12034/j.issn.1009-606X.221187 Abstract （340）      PDF （2353KB）（220）       Knowledge map    Save In recent years, China has successfully developed coal-based methanol to olefins (MTO) production processes and technologies, which has promoted the rapid development of the coal-to-olefins industry and guaranteed national energy security. The fluidized bed reactor is the core reaction device for the industrial production of methanol to olefins. It is of great significance to deeply understand the fluidization characteristics of the MTO fluidized bed through computational fluid dynamics. It can give more accurate guide for optimization and amplification of MTO fluidized bed. In this work, the multi-scale computational fluid dynamics (CFD) method which is coupling of bubble-based EMMS drag and traditional TFM is adopted to perform 3D simulation of the multi-phase flow behavior inside an industrial-scale MTO fluidized bed. This multi-scale CFD method involves in the influence of the bubble-based structure on the gas-solid drag coefficient. Thus, it can more accurately predict the "S-shaped" distribution of the axial particle concentration inside the MTO fluidized bed, which is consistent with experimental data. The predicted radical distribution of particle concentration presents the classic "core-annulus" flow structure. The predicted distribution of the averaged gas/particle axial-velocity in the radial direction is also mutually confirmed with the actual situation. This multi-scale CFD method significantly improves the predictive ability of the traditional TFM based on uniform drag for the macroscopic flow field. In future, the focus will be put on extending this multi-scale CFD method to the optimization design and reaction characteristics of MTO fluidized bed. Related Articles | Metrics

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Progress on catalysts for hydrogen production by low temperature methanol water reforming Zhan SHEN Zhidong JIANG Pengfei ZHANG Ziyu ZHANG Haiying CHE Zifeng MA The Chinese Journal of Process Engineering    2022, 22 (5): 573-585.   DOI: 10.12034/j.issn.1009-606X.221147 Abstract （638）      PDF （1690KB）（216）       Knowledge map    Save Methanol is a promising energy carrier owing to its simple structure, high hydrogen content and huge production capacity. Methanol steam reforming (MSR) is an energy-saving and efficient on-site hydrogen production method. Combined with fuel cells, MSR can be applied in many fields. However, due to the high reaction temperature (250~300℃), there are some problems such as slow start-up, high CO content and low thermal efficiency. Low temperature methanol water reforming (LT-MWR), including LT-MSR and aqueous-phase reforming of methanol (APRM), means that the reaction proceeds below 200℃, and maintains high reaction activity, which can reduce the preheating time and the side reactions, and achieve stronger thermal coupling with fuel cells. In this review, the performance and defects of commercial catalysts are firstly introduced based on characterization results. The research of LT-MWR catalysts for hydrogen production is reviewed, including Cu-based catalysts, noble metal catalysts and photo-synergistic catalysts. The modification strategies for low temperature Cu-based catalysts are summarized, including synthesis methods, structure design and element doping. The commercial CuZnAlOx catalyst at home and abroad has the characteristics of high methanol conversion and good stability, despite its relatively high price and low activity below 200℃. Because the activity of Cu-based catalysts is greatly affected by temperature, the catalytic activity decreases sharply at low temperature. By appropriate modification, Cu-based catalysts can perform high activity at low temperature. Noble metal catalysts have high activity at low temperature, but they are expensive and the synthesis process is complex. Photo-synergistic catalysts are functional under the condition of light, which is still in the research stage. The synthesis method can strengthen the micromixing degree and reproducibility. Appropriate structure design can increase the specific surface area and thermal stability of the catalyst. Element doping enables better dispersion of active components and modifies the surface structure. Three modification strategies can effectively improve the performance of Cu-based catalyst for LT-MSR, reducing the content of CO content while maintaining high activity. Finally, the prospect and challenges of LT-MSR catalysts for hydrogen production are prospected. Related Articles | Metrics

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Techniques of recycling gallium from e-waste Yifan YANG Guoqin LENG Boli CHEN Zhaohui HUANG Zhi SUN Tianyi TAO The Chinese Journal of Process Engineering    2021, 21 (6): 639-648.   DOI: 10.12034/j.issn.1009-606X.220167 Abstract （375）      PDF （1239KB）（215）       Knowledge map    Save As an important rare element, gallium has a wide range of applications in many fields such as industry, medicine, military, etc. However, due to the low concentration of gallium in the earth's crust and its wide distribution, it exists in the form of chalcopyrite. It is generally recovered from the by-products of gallium-containing waste in traditional industries such as sphalerite, aluminum ore, fly ash, etc. Gallium-containing electronic waste can be divided into two types of waste electronic products and gallium-containing waste generated in the production process. To solve the problem of shortage of gallium resources, researchers currently recover gallium from gallium-containing electronic waste. Due to the associated heavy metals, flammable organic substances, and other harmful substances, it has the dual attributes of environment and resources extensive attention. Gallium mainly exists in the form of compounds in e-waste such as GaN, GaAs, CIGS, IGZO, and has the characteristics of many associated elements and stable physical and chemical properties. Generally, the fire or wet method is used to recover gallium from GaN waste; gallium of GaAs waste is mostly obtained by wet method; gallium is extracted from IGZO (GZO) display screen by acid leaching and then purified. This article systematically sorts out the current status of gallium-containing electronic waste recycling and treatment, summarizes the applications of hydrometallurgy, pyrometallurgy, and biometallurgy in recycling different types of gallium-containing electronic waste. The difference in the use of material recovery technology and the separation and purification methods points out the current technical problems and the future development direction of recycling gallium-containing electronic waste. Related Articles | Metrics

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Cover and Contents The Chinese Journal of Process Engineering    2021, 21 (10): 0-.   Abstract （189）      PDF （1176KB）（211）       Knowledge map    Save Related Articles | Metrics

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Factors affecting the critical flux in a forward osmosis membrane process Ye YANG Rui TANG Yuzhu SUN Xingfu SONG Jianguo YU The Chinese Journal of Process Engineering    2021, 21 (5): 579-586.   DOI: 10.12034/j.issn.1009-606X.220134 Abstract （375）      PDF （851KB）（210）       Knowledge map    Save Critical flux is an important concept in fouling control for membrane-based processes. Operation below the critical flux can maintain the membrane flux and reduce the maintenance cost which is associated with membrane cleaning and replacement in forward osmosis (FO) processes. In this research, the effects of foulant type, binding ions concentration, and cross-flow velocity on the critical flux in FO processes were investigated using a draw solution concentration stepping method. The results showed that the draw solution concentration stepping was feasible for the critical flux determination in FO processes. The thin-film composite (TFC) membranes exhibited a low critical flux for sodium alginate (SA) fouling with a value of 29.32 L/(m2?h), then followed nano-silica (SiO2) with a critical flux value of 32.17 L/(m2?h) and humic acid (HA) of 46.35 L/(m2?h). This indicated that the critical flux behavior in FO processes was dependent on the properties of both the membrane and foulants, including the membrane surface roughness, intermolecular adhesion of foulants, and the interaction between foulants and membrane. The atomic force microscopy (AFM) results revealed the deposition of foulants onto the ridge-and-valley structure of the membrane surface, leading to the deviation of water flux from the baseline with the increasing draw solution concentration. As the Ca2+ concentration increased from 0 mmol/L to 10 mmol/L, the critical flux for alginate fouling dramatically decreased from 29.22 L/(m2?h) to 9.48 L/(m2?h), which can be attributed to the interaction between alginate and membrane as well as the intermolecular aggregation of alginate and the interaction by Ca2+ binding. Moreover, the critical flux for SA?Ca2+ complexes fouling increased from 9.48 L/(m2?h) to 31.59 L/(m2?h) with the cross-flow velocity ranging from 5 cm/s to 15 cm/s, which indicated the improvement of the solution turbulence can enhance the critical flux, thereby expanding the operating ranges of flux. Related Articles | Metrics

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Research progress of continuous generation of microbubbles by microdispersion Bingqi XIE Caijin ZHOU Xiaoting HUANG Xiangdong MA Jisong ZHANG The Chinese Journal of Process Engineering    2021, 21 (8): 865-876.   DOI: 10.12034/j.issn.1009-606X.220341 Abstract （405）   HTML （179）    PDF （9216KB）（209）       Knowledge map    Save Microbubbles have been drawn more attentions due to their widely applications. At present, the preparation methods of microbubbles mainly include ultrasonic, electrolytic process, dissolved air flotation and microdispersion. Compared with traditional methods of microbubble generation, the microchannel technology has the advantages of high production efficiency, good controllability, excellent flexibility, which has been applied to produce the monodisperse microbubbles and drops. And the microchannels devices with different structures, such as co-flowing microfluidic, flow focusing, T-microchannel and venturi devices are an all-around introduced in this paper. In the process of gas-liquid membrane dispersion, the microbubbles size is affected by many factors, such as liquid flow velocity, liquid surface tension, liquid viscosity, the pore size, porosity, pore structure of membrane and gas flow velocity. So far, the mechanism of microbubbles formation is complicated, which is still not clear. Moreover, it is also critical important to rapidly and accurately measure the size and distribution of microbubbles due to the wide application of microbubbles. Traditionally, the size and distribution of microbubbles are measured by probes and laser particle analyzer, which is efficient and easy accessibility. However, the insertion of probes will affect the flow filed and the mechanism of lase particle analyzer is not clear. With the rapid development of digital image recognition technology, combination of high-speed camera and digital image recognition technology provides an effective, visual and accurate online microbubbles recognition method to measure microbubbles size. Furthermore, the application of deep learning technology in the recognition of microbubbles has drawn more attentions. In this work, the commonly characterization methods of microbubble size are summarized. In addition, the advantages and disadvantages of different methods of preparation microbubbles are also expounded and the current research status of microchannel method and gas-liquid membrane dispersion method are mainly introduced. On this basis, the future research directions of microbubbles prepared by microdispersion are prospected. 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 （394）   HTML （21）    PDF （13593KB）（207）       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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Research status of strengthening methods for gas hydrate formation process Qi ZHAO Zhaoyang CHEN Zhiming XIA Yu ZHANG Chungang XU Xiaosen LI The Chinese Journal of Process Engineering    2021, 21 (9): 993-1002.   DOI: 10.12034/j.issn.1009-606X.220296 Abstract （339）      PDF （1562KB）（206）       Knowledge map    Save Based on the special physical and chemical properties of hydrate, as a new technology, method of gas hydrate is widely used in many fields, such as desalination, solid state storage and transportation of natural gas, gas separation, carbon dioxide capture and storage, etc. But due to the harsh conditions of hydrate formation, its formation rate and gas storage capacity are still far behind that of commercial applications, so special technical means are needed to reduce hydrate formation conditions and strengthen hydrate formation rate and gas storage capacity. In this work, the research status of strengthening methods for hydrate formation process is reviewed from three aspects: mechanical strengthening, outfield action and additives, and the development of technology in the future is prospected. From the point of view of the strengthening method, the mechanical strengthening technology is relatively mature, but the energy consumption required by mechanical stirring and the heat energy generated by the stirring process are both large, and increase geometrically with the increase of the device. The most extensive research on the reinforcement of additives, the effect is relatively ideal, but the reinforcement method of additives will inevitably bring new pollution to the system or products, not conducive to the actual promotion and application. There are few studies on field reinforcement, which are still in the experimental and even theoretical stage, and there is still a large space for development and improvement. Related Articles | Metrics

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Research progress in preparation of large pore pseudoboehmite and γ-Al2O3 carrier Yongjia YANG Xinsheng ZHANG Jin LI Chunguang ZHANG Yuansheng ZHAO Shili ZHENG Ping LI The Chinese Journal of Process Engineering    2021, 21 (10): 1156-1166.   DOI: 10.12034/j.issn.1009-606X.220368 Abstract （462）      PDF （4364KB）（204）       Knowledge map    Save γ?Al2O3 is widely used as catalyst carrier in petroleum processing realm, owing to its porosity, high dispersibility, adjustable surface acid/base characteristics, attractive mechanical properties and good thermal stability. As the quality of crude oil is increasingly heavy and inferior, more and more attention has been paid on the preparation of macro-mesostructured γ?Al2O3 since the γ?Al2O3 as the catalysts carrier, that used in the heavy oil processing, such as fixed-bed residue hydrotreating or RFCC, need more meso-and macroporous structures to reduce the internal diffusion resistance of large molecules and improve the catalytic activity. Commonly, pseudoboehmite as the raw materials turns decisive significance for the physiochemical properties of γ?Al2O3. For instance, the pore properties of γ?Al2O3 are greatly in?uenced by the size and morphology of pseudoboehmite crystallites and their aggregation. This manuscript thus reviewed the representative preparation methods of pseudoboehmite including precipitation method and aluminium alkoxide hydrolysis method. The advances of Al2(SO4)3?NaAlO2 method and carbonization method, as two main industrial technologies, were emphatically introduced. New reactors and technologies for the precipitation were developed in order to provide su?cient mixing intensity and recirculation of different reactants, which could bring about a homogeneous supersaturation distribution in the instantaneous neutralization reaction, and then lead to uniform crystallites size, thereby pseudoboehmite with large pore volume and narrow pore size distribution. Besides, the relative meso??and macroporous structures control technologies were also highlighted, such as pH swing method, pore-enlarging additives method, and hydrothermal treatment method, etc. The advantages and disadvantages of these methods were also briefly analyzed. At last, the development trend was introduced and some suggestions were proposed. Related Articles | Metrics

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Study on sulfur removal from ferric phosphate by high-temperature calcination Wenbo LOU Ying ZHANG Yang ZHANG Xiaojian WANG Jianzhong LI Shan QIAO Shili ZHENG Yi ZHANG The Chinese Journal of Process Engineering    2022, 22 (2): 268-275.   DOI: 10.12034/j.issn.1009-606X.221043 Abstract （1180）      PDF （1247KB）（203）       Knowledge map    Save Iron phosphate is the main material for the synthesis of lithium iron phosphate battery cathode material, which is mainly produced by co-precipitation method of using ferrous sulfate and phosphate salt. The sulfur content in the iron phosphate prepared by the co-precipitation process in the sulfate system is high, which has to be removed by washing with large amount of water of around 60~100 tons per ton of iron phosphate, bringing a huge burden of sulfate-bearing wastewater treatment. To reduce the amount of wastewater from the source, this research proposed an alternative way for desulfurization by high-temperature calcination based on the feature of sulfate decomposition at high temperatures. The thermodynamic feasibility and kinetics of the desulfurization were studied. The results showed that the sulfur in ferric phosphate existed in the form of sulfate, which can be effectively removed by high-temperature calcination. A higher temperature was preferred for a more satisfactory desulfurization efficiency. Kinetic study uncovered that the desulfurization reaction order was 2, and the activation energy was 88.075 kJ/mol, indicating a chemical reaction control mode. The sulfur content in iron phosphate can be reduced to less than 0.01wt% by calcining at 1173 K for 10 min. Related Articles | Metrics