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Surface modification and catalytic performance study of Cu-based carbon dioxide to methanol hydrogenation catalyst Qiang YANG Gang WANG Chunshan LI The Chinese Journal of Process Engineering    2024, 24 (10): 1166-1176.   DOI: 10.12034/j.issn.1009-606X.224059 Abstract （1303）   HTML （28）    PDF （3618KB）（392）       Knowledge map    Save Development of effective copper-based catalyst for CO2 hydrogenation to methanol is of great significance, considering the utilization of this greenhouse gas. In this work, a series of surface promoter-modified (Mn, In, Mo, Mg, Zr) catalyst were synthesized by coprecipitation-post impregnation method and evaluated for CO2 hydrogenation to methanol in fixed-bed reactor. The role of metal modifier on the physicochemical properties of Cu/ZnO/Al2O3 (CZA) were investigated through CO2-TPD, XRD, XPS and H2-TPR. In addition, the catalytic mechanism for CO2-to-methanol hydrogenation was revealed by employing in situ IR. The results showed that the Mn-modified CZA with good reduction behavior, excellent CO2 adsorption capacity and suitable Cu+/Cu0 ratio exhibited the best performance. The metal element loaded on catalyst strengthened the interactions between the copper and support, suppressing the growth of Cu. The appropriate Cu+/Cu0 ratio facilitates the stabilization and conversion of methoxy, resulting in increased methanol production. Compared to the untreated CZA catalyst, the Mn-modified catalyst has more medium strong base sites on the surface, which helps to adsorb more CO2 for further hydrogenation to form formate, methoxyl and other intermediates. The incorporation of metal component in CZA facilitated the catalyst reduction ability. The catalytic mechanism follows the formate pathway and the methoxyl species is the crucial intermediate. The Cu nanoparticles on the catalyst surface showed an increased capacity for H2 dissociation when using Mn-modified CZA catalysts. This is due to stronger metal-carrier interactions. The presence of interstitial H in the carriers contributed to the generation of formate species. The dissociated H atoms from the surface Cu nanoparticles replenished the consumed interstitial H. The modified catalyst's interstitial H presence and enhanced H2 dissociation ability accelerated the formation and conversion of intermediate species, promoting methanol generation. Related Articles | Metrics

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Research on the removal process and mechanism of aluminum/iron impurities from wet phosphoric acid through deep extraction Youzhi DAI Ganyu ZHU Ziheng MENG Huiquan LI Chengjin XU Guoxin SUN Fang LI Lei HE Yongfang ZHANG The Chinese Journal of Process Engineering    2024, 24 (10): 1241-1250.   DOI: 10.12034/j.issn.1009-606X.224056 Abstract （1164）   HTML （8）    PDF （4480KB）（192）       Knowledge map    Save The presence of impurities in phosphoric acid hinders its application in downstream processes. The development of wet-process phosphoric acid deep purification technology enables the direct preparation of phosphate-based new energy materials through a simplified process, which represents the mainstream direction for industry advancement. The solvent extraction method was employed for the extraction and separation of Al and Fe impurities in wet-process phosphoric acid. The effects of different extractants, temperature, O/A ratio, time, and extractant content on the separation efficiency of Al and Fe impurities were investigated. Optimal conditions were determined as follows: N,N-N-octyl amine di (methylene phenylphosphonic acid) (OADMPPA) extractant, extractant content of 20wt%, time of 3 min, temperature at 25℃, O/A ratio of 1:1 and 3-stage cross-flow extraction. Under these conditions, the extraction rates for Al and Fe reached 54.5% and 99.6%. Consequently, the contents of Al and Fe impurities in phosphoric acid decreased from 0.857wt% and 0.175wt% to 0.717wt% and 0.015wt%. Additionally, the MER value reduced from 9.037% to 7.227%. Further optimization of stripping process of OADMPPA extractant loaded with Al and Fe was carried out, ammonium oxalate was identified as the optimal stripping agent. The optimized stripping conditions were as follows: 25℃, 5-stage cross-flow stripping, O/A ratio of 2:1, time of 15 min, and concentration of the stripping agent at 0.2 mol/L; the stripping efficiencies for loaded extractant Al and Fe reached 96.4% and 88.3%, effectively achieving their separation from the extractant phase. Finally, the mechanism behind Al or Fe extractants was investigated by stoichiometric calculation and Fourier infrared analysis during the extraction process. It was found that during this process, one molecule of Al combined with one-and-a-half molecules of OADMPPA extractant while one molecule of Fe combined with two molecules of OADMPPA extractant; functional groups involved in these interactions included P=O and P-O-H bonds. A competitive mechanism exists in the extraction process between Al and Fe, where Fe is more easily extracted. Related Articles | Metrics

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Research progress of lithium extraction technology from lepidolite Hong YANG Wei ZHONG Faping ZHONG Jiahui ZHAO Dong LI Lei ZHANG Xueyi GUO The Chinese Journal of Process Engineering    2024, 24 (11): 1251-1262.   DOI: 10.12034/j.issn.1009-606X.224019 Abstract （941）   HTML （22）    PDF （1677KB）（253）       Knowledge map    Save Lithium and its compounds are indispensable materials in modern industry and have important applications in the fields of batteries, ceramics and lubricants. China is rich in lithium resources, most of which occur in salt lake brine. However, due to the limitation of resource endowment and geographical location and climate, its production capacity cannot meet the needs of the rapid development of new energy industry in China, and lithium extraction from ores has become an important source of lithium products. Yichun, Jiangxi province has the largest associated lepidolite resources in China, and the development and utilization of lepidolite resources is of great significance to ensure the sustainable development of lithium resources in China. In this review, the principle, advantages and disadvantages of the existing lithium extraction processes from lepidolite are summarized. Based on the understanding of the existing methods, typical lithium extraction processes from lepidolite such as acid method, alkali method and salt method are summarized and evaluated. Among them, the acid method is mature, but there are some problems such as difficulty in impurity removal from leaching solution, low efficiency in lithium extraction and equipment corrosion. Although the alkali process has high efficiency of extracting lithium, its reaction mechanism is not clear, and the waste residue is difficult to use. Although the salt process has high selectivity to lithium and simple process, it also has the problems of high energy consumption and large amount of slag. The development direction of lepidolite extraction technology should focus on the collaborative treatment of multiple technologies to achieve efficient, economical and environmentally friendly extraction of valuable elements. Therefore, some measures to improve the process are put forward, aiming at providing reference for the future research, development, optimization and industrial application of the process. Related Articles | Metrics

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Leaching process and kinetics of niobium-tantalum concentrate by HF-H2SO4 mixed acid Gengyu LIANG Xuebin SU Huiwu LIU Kang LIU Hao CHENG The Chinese Journal of Process Engineering    2024, 24 (4): 470-479.   DOI: 10.12034/j.issn.1009-606X.223211 Abstract （922）   HTML （10）    PDF （2212KB）（186）       Knowledge map    Save As rare precious metals, niobium and tantalum are widely used in the fields of high-precision instruments and military equipment due to their excellent physical and stable chemical properties. China is rich in niobium and tantalum resources, most of which are associated deposits that coexist with various metal minerals and have high comprehensive utilization value. In response to the separation and recovery of uranium, thorium, and rare earth resources in niobium and tantalum concentrates, the HF-H2SO4 mixed acid method is used to preferentially extract niobium and tantalum, while enriching uranium, thorium, and rare earth in the slag. In this research, the one-factor experimental design is applied to study the leaching behavior of niobium and tantalum, meanwhile, the process mechanism and kinetics are discussed. The results show that using high concentration hydrofluoric acid, increasing the amount of hydrofluoric acid and sulfuric acid is beneficial for the leaching rate of niobium and tantalum. Reducing the ore particle size, increasing temperature, and extending leaching time all has favorable effect on the leaching rate of niobium and tantalum. The optimal leaching conditions obtained are as follows: 40wt% HF 1120 g/kg, H2SO4 392 g/kg, average particle size -25 μm (75%), leaching temperature 80℃, and leaching time 4 h. In which the leaching rate of niobium is greater than 98%, and that of tantalum is greater than 97%. Uranium, thorium, and rare earth are retained in the slag, and the enrichment rate in the slag reaches 3.0 to 4.2. The kinetic research has shown that the leaching process of tantalum and niobium conforms to the shrinkage core model and belongs to the chemistry and diffusion mixed control. The apparent activation energy of Nb obtained from the experiment is 34.00 kJ/mol, and that of Ta is 36.26 kJ/mol. This method effectively extracted niobium-tantalum and enriched the other valuable elements, which build the foundation for the design of the separation and purification process. Related Articles | Metrics

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Investigation of phase structure stability and thermal expansion coefficient of ytterbia stabilized hafnia Fei ZHOU Hao LAN Xiaoming SUN Huifeng ZHANG Yonghui SUN Lingzhong DU Weigang ZHANG The Chinese Journal of Process Engineering    2024, 24 (5): 580-588.   DOI: 10.12034/j.issn.1009-606X.223074 Abstract （900）   HTML （6）    PDF （4295KB）（104）       Knowledge map    Save Improvement of the thrust weight ratio of gas turbine engine rely on increased engine operating temperature. At present, it is a priority to find new thermal barrier coating ceramic materials with a higher temperature tolerance than the traditional YSZ (Yttria partially stabilized zirconia) material and match thermal expansion coefficient of Ni-based superalloy matrix. A series of ytterbia stabilized hafnia (YbSH) were prepared with hydrothermal nano-powders by solid-state sintering. Effects of the ytterbia on the microstructure, phase stability, and thermal expansion coefficient of the doped hafnia ceramics were investigated. The microstructure and phase stability mechanism of Yb2O3-doped HfO2 powders and ceramics were analyzed by XRD, Raman, and TEM. DSC-TG and TMA were used to test the high temperature phase structure stability and thermal expansion coefficient of cubic phase structure of YbSH ceramics. The results showed that the grain size of the hydrothermal nano-powder was less than 10 nm, with a uniform distribution and a great crystal state. Most of the powers were cuboid and the density of the sintered ceramics can reach more than 95%. Crystallography analysis revealed that the Yb(III) ion distorted the lattice by replacing Hf(IV) ion position which made the space group of HfO2 from monoclinic phase distortion of P21/c to the cubic phase Fmˉ3m. The hafnia gradually lost its monoclinic phase structure with increasing doping amount of ytterbia, once the doping concentration of ytterbia raised up to 12 mol/mol. By expanding cationic network and generating oxygen vacancy, oxygen overcrowding was effectively alleviated. The cubic phase structure showed good stability from room temperature to 1500℃ by high temperature heat treatment and monitoring enthalpy change of YbSH nanopowders and ceramics during heating process. Average thermal expansion coefficients of YbSH ceramics increased with cubic phase content increasing from 6.016×10-6℃-1 to 10.14×10-6℃-1 (from room temperature to 1500℃). The thermal expansion coefficient of YbSH ceramics doped with 20 mol/mol ytterbia can reach 10.5×10-6℃-1 (from 1000℃ to 1200℃), which was 67.22% higher than that of pure hafnia. Related Articles | Metrics

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Study of flow field characteristics and separation performance of inline cyclone gas-liquid separator Ming ZHANG Huan SUN Qiangqiang WANG Jiaqing CHEN Chao SHANG Xiang LI Chunsheng WANG Lingzhen KONG The Chinese Journal of Process Engineering    2024, 24 (7): 772-782.   DOI: 10.12034/j.issn.1009-606X.223312 Abstract （769）   HTML （13）    PDF （6151KB）（209）       Knowledge map    Save The inline cyclone gas-liquid separator has received much attention because of its high separation efficiency and compact structure, but the ability to adapt to a wide range of inlet gas holdup is the key to its practicality. In this work, the flow field characteristics and separation performance of a inline cyclone gas-liquid separator that can adapt to a wide range of gas holdup changes are investigated by computational fluid dynamics (CFD) and experimental tests in air-water media system. The CFD numerical simulation results show that when the inlet gas holdup changes in the range of 10%~90%, the gas-phase separation efficiency is greater than 80% and the amplitude of change is less than 9.9%, and the liquid-phase separation efficiency is greater than 97% and the amplitude of change is less than 2.2%. The experimental results show that when the inlet gas holdup changes in the range of 9.4%~89.2%, the liquid holdup of the gas-phase outlet gradually decreases and the gas holdup of the liquid phase outlet gradually increases with the increase of the inlet gas holdup. The liquid holdup of the gas-phase outlet is less than 4%, and the gas holdup of the liquid-phase outlet is less than 10% except at liquid flow rate of 12 m3/h. Comparing the gas-phase separation efficiency and liquid-phase separation efficiency under different liquid flow rates, the best separation performance is achieved at a liquid flow rates of 8 m3/h. The CFD numerical simulation results are slightly different from the experimental test results, but the overall trend is consistent, which can be used as an effective tool for the design of structure enlargement. The research results show that the inline cyclone gas-liquid separator adopts the action form of "strong cyclone+weak cyclone+gravity", which has high separation efficiency and good resistance to fluctuations in working conditions. Related Articles | Metrics

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Heat and mass transfer simulation of gas-liquid two-phase flow in a distillation column based on OpenFOAM Yunpeng JIAO Xiaoqing ZHOU Jianhua CHEN The Chinese Journal of Process Engineering    2024, 24 (4): 391-402.   DOI: 10.12034/j.issn.1009-606X.223180 Abstract （767）   HTML （16）    PDF （4117KB）（369）       Knowledge map    Save For multiphase mass transfer processes in distillation columns, computational fluid dynamics can be used not only to simulate the flow phenomena, but also to study the heat and mass transfer processes and their interactions with the flow. Based on previous work on gas-liquid flow simulation in distillation trays, this work applied the multiphase flow solver of the OpenFOAM platform. The energy and species transport equations were considered to construct the heat and mass transfer models for the distillation system. The ideal system of cyclohexane-n-heptane and the non-ideal system of ethanol-water distillation were simulated respectively. The distribution of the gas-liquid two-phase flow, component and temperature on the column trays were analyzed. For the ideal system, the ideal solution mass transfer model can provide accurate predictions for the temperature and concentration fields on the trays. However, for non-ideal systems, it was necessary to introduce the activity coefficient model on the basis of the ideal model. To this end, the effects of two activity coefficient models, UNIQUAC and NRTL, were introduced and compared. In the current simulation framework, the activity coefficient models were able to improve the simulation accuracy of temperature and concentration field. The overall trends predicted by the two models were generally consistent with the results in the literature, and the UNIQUAC model agreed better with the literature. In addition, the comparative analysis of gas-liquid two-phase flow field and concentration field distribution showed that the circulating flow of liquid phase can enhance the local mass transfer efficiency of the column tray, resulting in higher efficiency at the liquid inlet and the weir than the tray center. However, the gas-liquid renewal in the circulating region renewed ly, which led to a reduction in the overall mass transfer efficiency of the column tray. This study can be used for the design and optimization of distillation columns, and it is also valuable for simulations of heat and mass transfer in other gas-liquid two-phase flow systems. Related Articles | Metrics

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Research progress of microreactor technology in gas-liquid two-phase flow systems Xinran YE Zan WU Haiou WANG Jianren FAN The Chinese Journal of Process Engineering    2024, 24 (9): 1001-1015.   DOI: 10.12034/j.issn.1009-606X.224035 Abstract （738）   HTML （26）    PDF （3984KB）（428）       Knowledge map    Save Microreactors possess advantages such as high heat and mass transfer efficiency, strict control of reaction parameters, ease of scale-up, and good safety performance, and hold promises for enabling and accelerating the discovery of flow chemistry towards highly efficient and more sustainable chemical synthesis. Gas-liquid multiphase catalytic reaction is commonly encountered in chemical production process, where the reaction stream enters the microfluidic channel in a continuous flow and undergoes rapid reaction. The combination of microreactor technology and gas-liquid multiphase catalytic reaction facilitates the development of efficient and sustainable chemical production techniques. Gas-liquid multiphase catalytic microreactors can be classified as wall-coated or filled-bed microreactors based on catalyst fixation approaches. By optimizing the geometric structure design of the microreactor, it is possible to further reduce the reaction time, minimize the material retention and suppress the occurrence of undesirable reactions, thus improving the microreactor performance. However, the optimization of microreactor structure requires a comprehensive understanding of various physics including the flow characteristics of gas-liquid fluids, the mass transfer mechanism and reaction kinetics within the microreactor. Both the flow pattern and mass transfer of multiphase fluids in microreactors will affect the reactor performance. Investigating the gas-liquid system in microreactors promotes improved design of practical devices. This review mainly summarizes typical gas-liquid microreactor examples, and hope to provide inspiration and guidance for the design, fabrication, and application of microreactors. The review is organized as follows, first, the features of microreactor technology are introduced and the optimization strategies for microreactor structures are presented, which is followed by a detailed discussion on the flow patterns, mass transfer characteristics and bubble breakup dynamics in gas-liquid multiphase systems within microreactors. Then, examples of multiphase catalytic microreactors in applications (mainly focusing on wall-coated microreactors and filled-bed microreactors) and their limitations are introduced. Finally, the research trends and application prospects in gas-liquid multiphase microreactors are envisaged. Related Articles | Metrics

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Preparation of high-purity copper by electrolytic refining in nitric acid system Mengyang LI Liang XU Tao GE Rui HE Xiaoyu HAN Cheng YANG Zhuo ZHAO The Chinese Journal of Process Engineering    2024, 24 (8): 955-963.   DOI: 10.12034/j.issn.1009-606X.223333 Abstract （736）   HTML （10）    PDF （2577KB）（258）       Knowledge map    Save High-purity copper has been widely used in semiconductor materials, optoelectronics and other fields due to its excellent physical and chemical properties such as ductility, thermal conductivity and electric conductivity. With the rapid development of electronic information industry, the copper product with high purity is pressing needed. Numerous methods such as zone melting, electron beam melting and electrolytic refining have been developed for the preparation of high-purity copper. Among these technologies, electrolytic refining has been investigated extensively and used in the industrial production for high-purity copper owing to its operation flexibility, simple-process and environmental-friendliness. In general, the electrolytic refining methods for the preparation of high-purity copper could be divided into nitric acid system and sulfuric acid system electrolytic refining. The electrolytic refining for high-purity copper preparation in sulfuric acid system has been widely used in industry. However, the high-purity copper prepared in sulfuric acid system generally contains the higher content of impurity elements such as S than in nitric acid system. Therefore, in this study, the 5N purity of copper was prepared from the raw materials of 4N copper in nitric acid system by one-step electrorefining. The effects of H2O2 addition, current density, electrolyte pH, Cu2+ concentration during the electrorefining process were systematically studied. Under the optimum conditions of Cu2+ concentration of 80 g/L, pH of 1.0, H2O2 addition of 0.10 mL/100 mL, and current density of 200 A/m2, the electrolytic product deposited on the cathode surface exhibited the smooth morphology, and the current efficiency during the electrorefining process was over 97%. Furthermore, the impurity elements including S, Ni, Se, As, Sb, Pb, Bi in the electrolytic product were detected by ICP-MS. The results showed that the purity of the copper prepared under the optimum conditions reached the 5N grade, which was consistent with the national standard of 5N high-purity copper. Related Articles | Metrics

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Research progress on preparation of magnetic activated carbon and its application in water treatment Qianyu WANG Yuming ZHANG Yanbin CUI The Chinese Journal of Process Engineering    2024, 24 (3): 259-272.   DOI: 10.12034/j.issn.1009-606X.223228 Abstract （698）   HTML （23）    PDF （2257KB）（388）       Knowledge map    Save Activated carbon (AC) has the characteristics of high specific surface area, porosity, abundant surface functional groups and chemical stability, and these advantages make it a widely used adsorbent in water treatment. After being exhausted (saturated adsorption contaminants), the spent AC needs to be separated from aquatic systems and regenerated which is conductive to materials recycling. However, it is difficult to efficiently separate the powder AC saturated adsorption contaminants from aquatic systems by traditional separation methods (gravitational sedimentation, centrifugation, filtration, and flotation), and the disadvantages for these methods root in many aspects including time-consuming, high-cost, and low separation efficiency. These limit the wide application of activated carbon in the field of water treatment to some extent. Magnetic modification treatment on AC can provide a magnetic activated carbon (MAC) which possesses better performances reflecting in higher adsorption capacity, and can be easier, rapid and efficient separation through external magnetic fields. At the same time, MAC has good catalytic activity, which is useful for enhancing the capability of advanced oxidation process to efficiently degrade organic pollutants in aquatic systems. Therefore, MAC has broad application prospects in the field of water treatment. This work mainly introduces the preparation methods (co-precipitation method, thermochemical method, and mechanical milling method), microstructure and physicochemical properties (specific surface area, pore structure, magnetism, crystal and chemical structure, surface charge) of MAC. The research progress of MAC in wastewater treatment in recent years is reviewed, consisting of organic pollutant removal, heavy metal removal and other applications. The adsorption characteristics (adsorption isotherms and adsorption dynamics) and corresponding influencing factors (adsorption temperature, solution pH, and coexisting ions) are summarized in details. And the regeneration methods of AC are investigated comprehensively. In the end, the development and prospect of the application of MAC in water treatment are also discussed. Related Articles | Metrics

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Recent progress of heterogeneous catalysts towards selective catalytic reduction of NO by CO under oxygen-rich conditions Yaqi LIU Yan LIU Ke WU Liwen XING Dianxing LIAN Mohaoyang CHEN Jianjun JI Yongjun JI The Chinese Journal of Process Engineering    2024, 24 (3): 284-296.   DOI: 10.12034/j.issn.1009-606X.223136 Abstract （651）   HTML （15）    PDF （3784KB）（413）       Knowledge map    Save Nitrogen oxides (NOx), as one of the predominant atmospheric pollutants mainly derived from automobile exhaust and industrial waste gas, have played the role of an inevitable precursor that led to acid rain, photochemical smog, and other environmental contamination issues. In addition to atmospheric pollution, the growing emissions of NOx pollutants also give rise to a serious threat to agricultural production and human health. Thus, it is of urgent need to develop feasible NOx abatement strategies. Selective catalytic reduction of NO by CO (CO-SCR) is a very promising denitrification technology that can simultaneously remove harmful gases of NO and CO, making it one of the most ideal solutions for flue gas treatment. To promote its industrial applications, CO-SCR should have a low operating temperature ranging from 150℃ to 250℃ and superior resistance to oxygen poison. Therefore, there is an urgent need to develop efficient CO-SCR catalysts used under oxygen-rich conditions for abating severe environmental pollution problems. This work provides a comprehensive review of the research progress and latest research findings of CO-SCR under oxygen-containing conditions. The research advances of Pd, Ir, Rh, Mn, and Co-based heterogeneous catalysts were introduced, and the effects of active components, promoters, and supports on the catalytic performance of CO-SCR are described in detail. In this section, the preparation method, doping modification, and reaction conditions are analyzed. Meanwhile, the impact of O2, H2O, and SO2 on the catalytic activity of CO-SCR is discussed, in which the inhibition mechanism of O2 is summarized. Finally, the challenges and future developments of CO-SCR under oxygen-rich conditions are summarized and the corresponding coping solutions are proposed. We hope this review can provide an in-depth understanding and useful guidance for the rational design of efficient heterogeneous catalysts for the CO-SCR reaction in practical applications. Related Articles | Metrics

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Research on composition customization strategy and magnetic properties optimization of soft magnetic composite cores based on interfacial solid reaction Rui WANG Hui KONG Haichuan WANG Lejun ZHOU Xi'an FAN Zhaoyang WU The Chinese Journal of Process Engineering    2024, 24 (10): 1196-1207.   DOI: 10.12034/j.issn.1009-606X.223366 Abstract （644）   HTML （3）    PDF （8243KB）（118）       Knowledge map    Save Soft magnetic composite cores (SMCs) are considered the most promising electromagnetic conversion device due to their excellent properties, including high saturation magnetisation, high permeability, and relatively low core loss. However, core loss and permeability, as the key performance parameters for the effective operation of electromagnetic devices, are often restricted. Therefore, by adjusting the distribution characteristics of the powder matrix, the insulating layer, and increasing the ferromagnetic filling factor within the soft magnetic composite core, in-situ coating of the insulating layer can be realised, which helps to simultaneously reduce core loss and improve magnetic permeability. In this work, a novel interface solid-phase reaction strategy was designed. Firstly, calcium acetate was uniformly coated on the surface of Fe-Si-Al soft magnetic alloy powder using hydrothermal method. Subsequently, Fe-Si-Al based soft magnetic composite cores were prepared by hot pressing sintering. The effects of sintering temperature and insulation layer phase transition on the morphology, microstructure, and magnetic properties of the prepared soft magnetic composite cores were studied. The results showed that calcium acetate was successfully coated onto Fe-Si-Al alloy powder surface by hydrothermal method, forming a core-shell heterostructure with the Fe-Si-Al alloy powder as the core and calcium acetate as the shell. This provided powder materials for subsequent preparation of soft magnetic composite cores. Raising sintering temperature eliminated internal pores within soft magnetic composite cores while promoting transition from calcium acetate to calcium carbonate to Al2O3?SiO2?CaSiO3, ultimately providing high-quality insulation. The insulating layer of the soft magnetic composite core prepared by high temperature sintering at 850℃ was dense and uniform, and the magnetic dilution effect was minimised. At 10 mT and 100 kHz, the soft magnetic composite core had the highest permeability (67.2), the lowest core loss (9.24×10-5 kW/cm3), and a relatively higher saturation magnetisation (129.0 emu/g), which had the best comprehensive performance, and provided a solution to restrict the reverse relationship between permeability and loss in traditional soft magnetic materials. Therefore, insulation methods based on thermal decomposition and oxidation of organic salt compounds are expected to be an important supplement to the magnetic property optimisation strategy of soft magnetic composite cores based on interfacial solid phase reaction engineering. Related Articles | Metrics

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Study on preparation and properties of electrospinning nanofiber membrane for air filtration Simin CHENG Fuping QIAN Chen ZHU Lumin CHEN Wei DONG Huaiyu ZHONG The Chinese Journal of Process Engineering    2024, 24 (5): 599-608.   DOI: 10.12034/j.issn.1009-606X.223252 Abstract （638）   HTML （5）    PDF （4750KB）（205）       Knowledge map    Save It has been proved by long-term practice that because the source of atmospheric aerosol particles is very wide, small size, the composition is very complex, the harm to the environment and human health is very serious. Although the government has taken a series of effective measures to control the pollution sources, it still takes a long time to completely solve the PM2.5 pollution problem. If the public wants to reduce the harm caused by particulate matter, specific measures must be taken to conduct individual protection and indoor air purification. At present, the simplest and most effective method for individual protection and indoor air purification is to filter the particles in the air through fiber filtration materials, thus reducing their content in the air. However, traditional fiber filtration materials have the disadvantages of low filtration efficiency, high filtration pressure drop and high energy consumption in the process of use. Meanwhile, filtration fibers with high filtration efficiency are often accompanied by higher filtration resistance. In order to develop high efficiency and low resistance fiber membrane for air filtration, polyacrylonitrile (PAN) electrospinning nanofibers were prepared by electrospinning. In the preparation process, the mass fraction of PAN and the duration of electrospinning were changed, and the electrospinning nanofiber films with different morphologies and filtration properties were obtained. The morphologies and filtration properties of electrostatic spinning nanofibers were tested and analyzed by field emission scanning electron microscopy and filtration test platform, and the preparation parameters of the best performance PAN electrostatic spinning nanofiber membranes were obtained with PAN mass fraction of 9wt%, electrospinning time of 5.0 h. Under the optimum condition, the film thickness of electrospinning nanofibers was 0.0240 mm, the average fiber diameter was 396 nm, the PM2.5 filtration efficiency was 99.99%, the filtration pressure drop was 67 Pa, and the highest quality factor was 0.137 Pa-1. Related Articles | Metrics

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Study on solid-liquid suspension characteristics in a slurry polymerization reactor with different impeller combinations Yang ZHAO Minghui XIE Jiawei XIANG Xiaoxiao LIU Shuailiang LI Shijun LÜ Liang WU Guozhong ZHOU Qinghua ZHANG Chao YANG The Chinese Journal of Process Engineering    2024, 24 (4): 403-413.   DOI: 10.12034/j.issn.1009-606X.223210 Abstract （607）   HTML （13）    PDF （5209KB）（259）       Knowledge map    Save Slurry process is the main production method for high-density polyethylene. For slurry of high-density polyethylene stirred polymerizer, three-blade-backswept impeller HQ, parabolic disc turbine impeller BTD, three blade hydrofoil impeller KHX, pitched blade disc turbine impellers ZY with blade placement angle of δ=45° and δ=75°, and straight blade disc turbine impellers PY160 were used to form four types of impeller combinations. Solid-liquid suspension experiments were conducted in a cylindrical perspex stirred tank with a diameter of T=480 mm. The CFD software Ansys Fluent 2020R2 combined multiple reference frame method and Euler-Euler multiphase flow model were used to study the solid-liquid suspension of each impeller combination at 30.71% solid holdup. The results showed that when the rotating speed N≤ 250 r/min, a clear liquid layer formed at the top of the mixing tank with impeller combination 2 and 3. Due to the inhomogeneous of solid holdup, the power of impeller combination 3 and 4 showed an inflection point at the rotating speed N=350 r/min. When the rotating speed N≤350 r/min, the combined power of each paddle type from low to high was: 2, 4, 3, 1. When the rotating speed N>350 r/min, the mixing power from low to high was: 2, 3, 4, 1. Impeller combination 1 and 4 can achieve uniform mixing at lower speeds and power, and the power consumption of impeller combination 4 was about 30% lower than that of impeller combination 1, so impeller combination 4 was high efficiency and energy conservation. The simulated results of solid holdup were in good agreement with the experimental values which was measured by the sampling method. The simulated flow field indicated that the flow patterns of impeller combination 4 and 1 were similar, which can effectively avoid the clear liquid layer appearing in impeller combination 2 and 3 at low rotating speeds. Related Articles | Metrics

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Research status and prospect of flash boiling spray Jian GAO Run HONG Wenlong DONG Nian XU Huaqiang CHU The Chinese Journal of Process Engineering    2024, 24 (3): 273-283.   DOI: 10.12034/j.issn.1009-606X.223157 Abstract （585）   HTML （17）    PDF （1493KB）（263）       Knowledge map    Save The rapid boiling that occurs when high-temperature fuel is injected into a low-pressure environment is called flash boiling, reasonable use of flash boiling phenomenon can effectively improve the atomization effect of fuel spray and improve engine efficiency. The research on the flash boiling phenomenon can be traced back to more than 60 years ago. With the development of the research on the flash boiling spray, the focus of the spray-related research has gradually shifted to the spray collapse. The related theories of flash boiling spray are summarized in this review, and some visualization techniques commonly used in the observation of flash boiling spray are briefly introduced. The influence of different fuel characteristics on the flash-boiling spray is illustrated by comparing different fuel characteristics. The characteristics of flash boiling spray of multi-component fuel are summarized. The superheat index which can be used to measure the flash boiling spray of multi-component fuel are introduced. The collapse mechanism of non-flash boiling spray and flash boiling spray and the influencing factors of spray collapse are studied by comparing the research status of non-flash boiling spray and flash boiling spray. It is generally considered that the collapse mechanism of non-flash-boiling spray is jet-induced collapse, and flash-boiling spray seriously affects the experimental observation because of too many droplets. Therefore, the understanding of the collapse mechanism of the flash boiling spray is numerous but not certain. In addition, according to the above summary, several feasible research directions are put forward for the spray research: effect of different fuel properties on flash boiling spray, study of parameters to measure the degree of superheat of multi-component fuels, the study on the collapse mechanism of the flash-boiling spray and the study on the suppression of the collapse of the flash-boiling spray. Related Articles | Metrics

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Porous PLGA microsphere as a vaccine adjuvant against COVID-19 Lingjiao ZOU Yu ZHANG Hua YUE Guanghui MA The Chinese Journal of Process Engineering    2024, 24 (3): 360-370.   DOI: 10.12034/j.issn.1009-606X.223218 Abstract （581）   HTML （19）    PDF （1841KB）（245）       Knowledge map    Save Poly (lactic-co-glycolic acid) (PLGA) nano-/microspheres have been proven to be effective as vaccine adjuvants. In current studies, the investigations on PLGA vaccine delivery microspheres have mainly focused on improving antigen loading/adsorption efficiency or co-delivery of multiple adjuvants to enhance the immunization effect. However, there is still a lack of discussion on the impact of the structural diversity of microspheres in promoting the vaccination effects. By rationalizing the design of the microsphere structure, we describe that the development of an effective SARS-CoV-2 vaccine adjuvant was achieved by the post-loading of SARS-CoV-2 antigen into porous PLGA microspheres, which provided non-destructive loading and prolonged release of antigen. In this work, PLGA porous microspheres and solid microspheres were prepared with the emulsification method, and there was no significant difference in microsphere particle size and surface potential between the two, except for the porous microspheres having cavities internally and tiny pores on the surface. Such characteristics of "large inner pores and tiny outer pores" enabled the antigen encapsulation efficiency to reach 10.81% at the antigen input concentration of 5.71 mg/mL. In terms of prolonging the in vivo retention of the antigen, the release endpoint in the antigen-loaded porous microspheres was prolonged to 15 days compared with that of the free antigen at 3 days and that of the solid microsphere-mixed antigen at 5 days. Concerning the enhancement of humoral immunization, compared with the solid microsphere vaccine group mixed with SARS-CoV-2 antigen, the porous microsphere vaccine group loaded with SARS-CoV-2 antigen had a higher onset of effect as the maximum value of the IgG titer rising rate, Vmax was 1.73 times higher; and the onset of effect was much earlier, as the time to reach the Vmax was 2.8 days earlier; also, the IgG antibody titer of which was higher during 6~16 weeks post-immunization, presenting a better antibody maintenance effect. Related Articles | Metrics

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Model development and validation of a structural two-fluid model for gas-solid bubbling fluidized beds Jiewen LUO Yabin WANG Wen LI Guosheng WANG Bidan ZHAO Junwu WANG The Chinese Journal of Process Engineering    2024, 24 (4): 435-444.   DOI: 10.12034/j.issn.1009-606X.223225 Abstract （565）   HTML （15）    PDF （3392KB）（226）       Knowledge map    Save Bubbling fluidized beds have been widely used in industrial applications because of its good mass and heat transfer behavior, where the heterogeneous structures such as bubbles are widely present, and these complex structures significantly affect the mass, momentum, and heat transfer as well as chemical reactions in the fluidized bed. The continuum model is selected to simulate the industrial fluidized beds by considering both of the computer cost and efficiency. In order to improve the accurate prediction of the continuum method simulation, it's very important to quantify reasonably the relationship between heterogeneous structures and three transfers/chemical reactions. The structure two-fluid model has been proposed as a novel continuum model, which has taken into account the influence of the heterogeneous structures such as particle clusters in the governing equations and the constitutive relations, therefore, this method is a complete and logically self-consistent in terms of heterogeneous structures. In this study, the structural two-fluid model is extended to the numerical simulation of bubbling fluidized bed: in the deducing the governing equations, the heterogeneous gas-solid system is divided as the particle-dominated emulsion phase and gas-dominated bubble phase, which are defined as two continuous fluids and permeate each other; for closing the constitutive relations, the involved bubble diameter, solid fraction in the emulsion phase and its viscosity have considered the influence of heterogeneous structures such as bubbles by some empirical correlations. As shown in the simulated results, the structural two-fluid model can successfully predict the hydrodynamics characteristics of gas-solid flow in the bubbling beds, thus validating the applicability of the structural two-fluid model in the simulation of bubbling fluidized beds. Moreover, the bubble size as an essential factor has an impact on the interaction between bubble phase and emulsion phase, which leading to the different simulation results with different bubble size correlations. Related Articles | Metrics

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Key technologies and advances of positron emission particle tracking Kun LI Liyun WU Ping CHEN Yan HAN The Chinese Journal of Process Engineering    2024, 24 (4): 381-390.   DOI: 10.12034/j.issn.1009-606X.223266 Abstract （554）   HTML （19）    PDF （2513KB）（284）       Knowledge map    Save Measuring multiphase flow parameters and the understanding of multiphase flow mechanisms are of great importance value for the design, operation, and optimization of industrial process devices. Due to the inherent multiscale nature of multiphase flow, its flow field often has great complexity, which makes our understanding of its flow process relatively limited. There are still many key issues that need to be explored in the mechanism of multiphase flow. Positron emission particle tracing (PEPT) is a new undisturbed and non-destructive imaging method for complex multiphase flows in industrial processes. γ photon detection is used to perform 3D dynamic imaging of radioactive labeled tracer particles. Due to γ photons have high penetration and are not affected by electromagnetic fields, making PEPT a unique advantage in detecting non-transparent and complex industrial multiphase flows. Currently, it is mainly used for measuring multiphase flow phenomena and extracting system physical parameters in industrial fields such as chemical, food, and pharmaceutical industries. However, the difficulties in preparing miniaturized tracer particles and the poor localization effect of multiple tracer particles at the same time seriously hinder the further application and promotion of PEPT technology. In this work, basic principles of PEPT technology are firstly briefly introduced, then the key technologies and research progress of PEPT are discussed from the aspects of tracer particles, algorithms, hardware systems and data processing in applications. The existing problems and potential development directions are pointed out. Finally, the development and application of PEPT is summarized and prospected. Related Articles | Metrics

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Fault diagnosis based on DA-CycleGAN for multimode chemical processes Wenjing CHEN Changchun DAI Yagu DANG Yiyang DAI Xu JI The Chinese Journal of Process Engineering    2024, 24 (5): 618-626.   DOI: 10.12034/j.issn.1009-606X.223316 Abstract （553）   HTML （10）    PDF （1362KB）（275）       Knowledge map    Save In modern chemical processes, timely and accurate fault diagnosis is important for enhancing the safety and reliability. Data-driven fault diagnosis methods have been regarded as a promising approach in the last decades of research for increasingly complex chemical processes. Data-driven fault diagnosis methods can greatly reduce the dependence on human experience, and realize end-to-end fault diagnosis by automatically extracting features. However, most existing research assumes training and testing data come from the same distribution, while a chemical process may have multiple working conditions. On the one hand, the fault diagnosis performance of the model will deteriorate when the process is run under new working conditions. On the other hand, due to the low probability of failure, some operating conditions may have few fault data in history. To address these issues, in this work, a novel fault diagnosis method, DA-CycleGAN, is proposed for multimode chemical processes. This study is the first to overcome the degradation of model diagnosis performance when only normal data are available under new working conditions. It notes that the normal data is available under any working condition. A two-dimensional CycleGAN is used to capture the temporal and spatial features of fault data. And fault data is generated by combining fault features and normal data under new operating conditions, thus filling a blank in new working conditions for fault data. Furthermore, the domain adaptation method is used to minimize the distribution differences between historical fault data and generated data and to improve the fault diagnostic performance under new operating conditions. To test the performance of this method, four working conditions of the Tennessee-Easthman (TE) process are used in the experiment. The results on twelve condition-changed fault diagnosis tasks show that this method can improve the average fault diagnosis rate by more than 3% compared to the model trained using only historical fault data. Related Articles | Metrics

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Numerical simulation of self-baked electrodes in a Titanium slag three-phase arc furnace Quan LIU Xiaoping GUAN Ning YANG Jun XIAO The Chinese Journal of Process Engineering    2025, 25 (4): 323-331.   DOI: 10.12034/j.issn.1009-606X.224185 Abstract （526）   HTML （23）    PDF （3911KB）（123）       Knowledge map    Save During the smelting process, the sintering quality of self-baked electrodes determines whether the arc furnace can operate normally. Taking the Panzhihua Steel Titanium Slag Three-Phase Arc Furnace as a prototype, this paper establishes a multi-physics field model of the coupled electromagnetic field and temperature field, and develops a quick calculation method for electromagnetic field and temperature field to accelerate computation. A comparative analysis of current density, Joule heat, and temperature distributions during the baking process of solid/hollow self-baked electrodes is conducted. The results show that both solid and hollow electrodes exhibit a "low at the center, high at the edge" current density distribution, namely the skin effect, with the skin effect of hollow electrodes weaker than that of solid electrodes, resulting in a more uniform current distribution. Besides, the baking regions of solid and hollow electrodes are located within the contact area of the conductive components, indicating that the self-baked electrodes have enough strength to meet the baking requirements. Meanwhile, the time to reach baking equilibrium for solid and hollow electrodes is about 13.4 hours and 12.8 hours, respectively, with the baking time of hollow electrodes being 4.3% shorter. Related Articles | Metrics

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Study on flow characteristics and clarification process of glass melt in 700 t/d float glass furnace Mingfang JIN Feng HE Junlin XIE Shuxia MEI Quanliang LI The Chinese Journal of Process Engineering    2024, 24 (4): 425-434.   DOI: 10.12034/j.issn.1009-606X.223215 Abstract （508）   HTML （10）    PDF （3711KB）（87）       Knowledge map    Save It is well known that the flow and clarification process of glass melt are critical to glass production control and product quality. To explore the flow characteristics and clarification process of glass melt in float glass furnace, the flow field and temperature distribution were studied. From a new perspective the numerical simulation of the flow and heat transfer process of glass melt were carried out for a glass tank under actual working conditions by using Ansys CFD software. In view of the simulation results on flow field and heat transfer of glass melt in float glass furnace, the temperature distribution and flow characteristics of glass melt in the furnace were analyzed and the clarification process of the bubbles in glass melt was further analyzed on this basis. It was found that along the furnace length, the temperature of the glass melt on the surface and at the bottom of the tank showed two mountain shaped distributions respectively, and the flow pattern of glass melt presented three large circulation flows in the tank. In the clarification section the forward and backward flow velocities of glass melt increased and then decreased. In the direction of tank depth from surface to bottom, the temperature of glass melt decreased in a gradient. At a depth of about 400 mm from the surface, the value of flow velocity was zero. After the hot spot, the flow above this surface flowed smoothly to the neck, and at the shortest time of 418 s. Within this time, bubbles larger than 1.2 mm in diameter can be eliminated before they reached the neck with the flow of glass melt, and whether the bubbles smaller than 1.2 mm in diameter can be eliminated or not needs further study on the pattern of bubble uplifting and changing. Related Articles | Metrics

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Process simulation of catalytic cracking of C5+ mixed olefins by-product of MTO to produce ethene and propene Rongheng GOU Mengfan YIN Tao ZHENG Jiawei ZHU Rui ZHANG Haiyan LIU Zhichang LIU Xianghai MENG The Chinese Journal of Process Engineering    2024, 24 (12): 1407-1416.   DOI: 10.12034/j.issn.1009-606X.224127 Abstract （506）   HTML （3）    PDF （836KB）（65）       Knowledge map    Save Methanol to olefin (MTO) is one of the important ways to produce ethene and propene, and mixed olefins are the main by-products of MTO process. C5+ mixed olefins by-product of MTO is currently sold at a low value in CHN Energy Xinjiang Chemical Company Limited, and has not been effectively utilized. In order to explore the high-value utilization way of C5+ mixed olefins by-product of MTO, its composition and physical properties were tested. It was found that the content of C5~C8 olefins in mixed olefins by-product of MTO was more than 80wt%, in addition, a small amount of alkanes, aromatics and oxygen compounds were contained. The catalytic cracking experiments of mixed olefins were carried out on a fixed-bed experimental device. Under the conditions of 0.1 MPa, 620℃, and mass space velocity of 3.53 h-1, the yields of ethene and propene were 15.31wt% and 26.94wt%, respectively. Combined with the process of MTO industrial plant, this study designed the process of mixed olefins catalytic cracking to produce ethene and propene, simulated the process based on Aspen Plus software, and optimized the operation parameters of the distillation column with high energy consumption. It was found that the optimal number of theoretical stages, feed stage and reflux ratio of the condensate stripping tower were 24, 12, and 1.2, respectively; those of the depropane tower were 20, 10, and 0.4, respectively; those of the deethane tower were 28, 9, and 3.4, respectively; those of ethene refining tower were 50, 21, and 7.5, respectively; those of propene refining tower were 54, 29, and 5.7, respectively; and those of light hydrocarbon separation tower were 12, 7, and 0.8, respectively. Finally, the product purity of ethene and propene reached 99.9wt% and 99.6wt%, respectively. The economic potential analysis results showed that compared with direct low value sales, the product income of mixed olefins catalytic cracking was 1.3 times of the original income. Related Articles | Metrics

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Research progress on dissolution behavior of drugs based on the drug-excipient interaction Kunwang SONG Yewei DING Chen SHEN Haomin WU Yuanhui JI The Chinese Journal of Process Engineering    2024, 24 (10): 1127-1136.   DOI: 10.12034/j.issn.1009-606X.224021 Abstract （505）   HTML （28）    PDF （840KB）（123）       Knowledge map    Save Pharmaceutical excipients, also known as "inactive ingredients", are other components in pharmaceutical preparations besides active ingredients. Pharmaceutical excipients are an indispensable and important component in pharmaceutical preparations, and they can significantly affect the release performance of pharmaceutical preparations by forming drug excipient interactions, which is crucial for the effectiveness and safety of pharmaceutical preparations. The development of high-end preparations also puts higher requirements on excipients. Therefore, it is necessary to analyze the mechanism by which excipients in high-end formulations affect the quality of drug formulations. Although the addition of excipients can enhance the release and bioavailability of active ingredients in drugs, improve and maintain drug stability, achieve controllable targeted release of drugs, and act as masking and sweeteners to improve drug bioavailability and patient adherence, more and more studies have shown that excipients can produce physiological activity and affect drug pharmacokinetics, causing adverse reactions such as allergies or intolerance. Large amounts of ingested excipients may also inhibit drug release by interacting with drugs. This review briefly describes the impact mechanisms of commonly used excipients on drug release from the perspective of drug excipient interactions, such as polymers and mesoporous silica. At the same time, it summarizes the research progress of excipient controlled drug release mechanisms based on mathematical models, molecular simulations, and machine learning methods based on drug excipient interactions, and proposes the development direction of future pharmaceutical excipient database establishment for high-throughput screening of suitable pharmaceutical excipients. Determine the optimal drug loading and excipient addition, and provide data support and theoretical guidance for selecting appropriate production processes. Related Articles | Metrics

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Research progress in preparation of silicon-based anode materials for lithium-ion batteries by radio-frequency induction thermal plasma Zongxian YANG Yuanjiang DONG Chang LIU Huacheng JIN Fei DING Baoqiang LI Liuyang BAI Fangli YUAN The Chinese Journal of Process Engineering    2024, 24 (5): 501-513.   DOI: 10.12034/j.issn.1009-606X.223230 Abstract （504）   HTML （27）    PDF （7425KB）（272）       Knowledge map    Save As one of the next-generation anode materials with the most promising application prospects, silicon anode benefits from a high theoretical specific capacity, a sufficient working potential, abundant and inexpensive sources, environmental friendliness, safety, and dependability. However, Si will experience significant volume variations throughout the lithiation and delithiation processes. This will result in significant internal stress, which will cause issues including material pulverization, repetitive growth of the solid electrolyte interface (SEI), and electrode failure. Through the utilization of nano-silicon-based anode materials, it is possible to effectively mitigate the volume impact, enhance both conductivity and stability. The utilization of radio-frequency (RF) induction thermal plasma offers several notable benefits, including elevated temperatures, rapid cooling, precise control, and uninterrupted operation. Thermal plasma has the ability to provide particles a unique growth environment and process that is helpful in the creation of products with special morphologies, such as zero-dimensional nanospheres and one-dimensional nanowires. Additionally, the extremely high temperatures can totally evaporate raw materials, guarantee uniformity of product, and be advantageous for doping second-phase materials. Consequently, it serves as a significant method for the production of nano-silicon-based anodes with a controllable morphology and structure, as well as high purity and excellent dispersibility. This work provides a review of the scientific advancements pertaining to silicon-based anode materials for lithium-ion batteries that are fabricated using RF thermal plasma. To commence, a concise introduction is provided for the thermal plasma technology. Then, this work focuses on the synthesis of various essential materials using thermal plasma, including silicon nanospheres (Si NSs), silicon nanowires (Si NWs), silicon monoxide nanowires (SiO NWs), silicon monoxide nanonetworks (SiO NNs), high-silicon silicon suboxide nanowires (SiOx NWs), silicon-based ferrosilicon alloy nanospheres (Si/FeSi2 NPs). Furthermore, the work emphasizes the applications of these materials in the anode electrode of lithium-ion batteries. Finally, the development of thermal plasma technology is prospected. Related Articles | Metrics

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Removal performance and mechanism of humic acid by persulfate activated with ultraviolet light combined with magnetic ion exchange resin Wenlong WU Yuchen GAO Jinwei ZHANG Ling LI Yan LI Yuchen ZENG Chun YANG Jiapeng LU Lei DING The Chinese Journal of Process Engineering    2024, 24 (5): 566-579.   DOI: 10.12034/j.issn.1009-606X.223268 Abstract （502）   HTML （6）    PDF （5338KB）（177）       Knowledge map    Save Humic acid (HA) in water was removed by activating persulfate with ultraviolet light combined with magnetic ion exchange resin. The removal efficiency of HA, the environmental factors affecting the removal of HA, the generation mechanism of active oxidizing species and the removal mechanism of HA in the ultraviolet light/persulfate/magnetic ion exchange resin (UV/PMS/MIEX) system were explored. The UV/PMS/MIEX synergistic system had a significant removal efficiency for HA in water, and the removal efficiency reached 91.71% after 120 minutes of reaction. The increase in resin dosage and temperature promoted HA removal, and increasing the concentration of persulfate could improve the removal efficiency of HA to a certain extent, but the effect of solution pH on the removal of HA was not obvious. In this system, the removal of HA was mainly through oxidation, and the adsorption effect WAs not significant. The iron oxides on the surface of the resin, the oxygen-containing functional groups and the addition of ultraviolet rays could effectively activate persulfate to produce various active oxidizing species such as ?OH, SO4?-, O2?-, and 1O2. In this system, HA fractions were degraded by the radical and non-radical pathways, and the activation mainly occurs through the radical pathway. Based on the characterization of N2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and X-ray photoelectron spectroscopy before and after the reaction, it can be found that the magnetic ion exchange resin exhibits good reusability and stability, and can effectively adsorb and remove various by-products in the system. This study provides a new method for HA removal in water, and the constructed oxidation system shows a good application prospect. Related Articles | Metrics

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Flow and mixing characteristics of a vortex static mixer Yifan ZHOU Guangyuan JIN Song WU Yuhao JING Zhengshan ZHU Wenkai FENG Chunfang SONG Zhenfeng LI Feihu SONG Jing LI The Chinese Journal of Process Engineering    2025, 25 (5): 471-482.   DOI: 10.12034/j.issn.1009-606X.224298 Abstract （502）   HTML （17）    PDF （7013KB）（89）       Knowledge map    Save Static mixers, which do not require external energy sources, are characterized by their compact design and ease of integration into systems, making them highly valued in the food processing industry. The introduction of vortices can significantly enhance the mixing efficiency of mixers, leading to improved reaction rates and overall effectiveness. Currently, most vortex static mixers achieve high-efficiency mixing by generating vortices through their internal structures, which must withstand the impact of flow and thus carry a risk of damage. Vortex tubes, characterized by their simple structure and strong vortex properties, have yet to be studied for their effectiveness in mixing. Based on this, this work investigates a vortex static mixer, employs numerical simulation methods to study its flow and mixing characteristics, focusing on the effects of inlet velocity and structural parameters such as the chamber aspect ratio (D/H) and the axial diameter ratio (D/Da). The results show that the internal flow is primarily dominated by vortices, accompanied by significant secondary flows, including secondary vortex circulation flow zone, shortcut flow zone, and eccentric vortex zone. Increasing the inlet velocity enhances the internal vortex flow and weakens the secondary flow, significantly reduces the intensity of separation at the outlet. When the inlet velocity reaches 0.223 m/s, complete mixing can be achieved at the chamber outlet. Reducing D/H or increasing D/Da can enhance the internal vortex. The mixing performance improves as the D/H decreases. Specifically, when the D/H is reduced from 6 to 4, the intensity of separation at vortex chamber outlet decreases from 4.03×10-3 to 5.23×10-4. Related Articles | Metrics

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Main advances in preparation technology of zirconia hollow microspheres Baoqiang LI Huacheng JIN Fei DING Chun WANG Fangli YUAN The Chinese Journal of Process Engineering    2024, 24 (6): 627-635.   DOI: 10.12034/j.issn.1009-606X.223297 Abstract （498）   HTML （13）    PDF （1939KB）（370）       Knowledge map    Save Zirconia hollow microspheres have attracted more attention because of their excellent performance, which combines the advantages of the properties of zirconia and hollow structural materials, such as low thermal conductivity, ablation resistance, and chemical corrosion resistance. Zirconia hollow microspheres is an important feedstock for preparing thermal barrier coatings. The thermal barrier coating prepared by zirconia hollow microspheres has the characteristic of excellent insulation and corrosion resistance. The performance of the coating is determined by the characteristics of the powder. The preparation of high quality zirconia hollow spherical powder has become a hot topic in the industry. In this work, the research status of the preparation technology of zirconia hollow spherical powder is analyzed, and the main preparation approaches are introduced, including templating, solvothermal, spray drying, and plasma sintering. In addition, the characteristic of these approaches is briefly summarized. Templating method contributes to obtaining hollow zirconia spheres with perfect morphology. However, some problems such as difficulty both in template synthesis and subsequent template removal, which can cause the material waste and damage to hollow particles. For solvothermal method, the reaction conditions are relatively harsh, and it also involves cumbersome process, such as separation, washing and drying process, which makes it difficult to batch preparation of hollow microspheres. The spray drying method is an effective approach for batch preparation of hollow microspheres. However, the hollow microspheres prepared by spray drying possesses have low strength and become easy to be damaged during application. Importantly, it is considered that the hollow microspheres prepared by spray drying combined with plasma sintering process have the advantages of high sphericity, good fluidity, and controllable particle size distribution, which are more conductive to preparation of coatings. Related Articles | Metrics

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Study on the heat transfer characteristics of nanofluid spray cooling with ethylene glycol aqueous solution as base fluid Nianyong ZHOU Yingjie ZHAO Yang LIU Youxin ZOU Guanghua TANG Qingguo BAO Wenyu LÜ The Chinese Journal of Process Engineering    2024, 24 (5): 514-522.   DOI: 10.12034/j.issn.1009-606X.223205 Abstract （472）   HTML （6）    PDF （3100KB）（68）       Knowledge map    Save In recent years, due to the improvement of power density, compact packaging and high performance requirements, the heat dissipation demand of high heat flux devices has increased significantly. In view of the above problems, this work plans to use the spray cooling technology to conduct heat transfer research on the Al2O3 nanofluid with ethylene glycol water as the base fluid, focusing on the analysis of the influence of the concentration of the base fluid, the concentration of nanoparticles, and the concentration of the added dispersant on the heat transfer performance of the working medium spray cooling at three different operating conditions of 300, 500, and 700 W. The experimental results show that due to the decrease of specific heat capacity and thermal conductivity and the deterioration of spray characteristics, the mass fraction of ethylene glycol increases from 30wt% to 80wt%, and the surface heat transfer coefficient of Al2O3 nanofluid solution decreases continuously, with an average decrease of 41.63%. The surface heat transfer coefficient of Al2O3 nanofluid shows a trend of first decreasing, then increasing, and then slowly decreasing with the increase of nanoparticle mass fraction. When the mass fraction of Al2O3 nanoparticles increases from 0 to 2wt%, the overall average surface heat transfer coefficient of Al2O3 nanofluid solution decreases by 6.94%. The deposition and bubbling effect are the main reasons for weakening the heat transfer. At the same time, the increase in the mass fraction of nanoparticles improves the thermal conductivity of the nanofluid solution, which to some extent enhances heat transfer. In addition, the addition of a low-quality non-ionic surfactant (Tween-20) can improve the foaming effect, making the heat transfer coefficient of spray cooling increase by about 1.52%, but still lower than that of pure base liquid; Adding a higher mass fraction of dispersant can cause aggregation between nanoparticles and further weaken the heat transfer performance of the thermal conductivity solution. Related Articles | Metrics

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Study on adsorption and oxidation mechanisms of H2S in blast furnace gas on hydroxyl iron oxide Xudong LIU Yuran LI Shuwen PENG Li LIU Wenqing XU Tingyu ZHU The Chinese Journal of Process Engineering    2024, 24 (12): 1417-1424.   DOI: 10.12034/j.issn.1009-606X.224002 Abstract （467）   HTML （4）    PDF （4860KB）（112）       Knowledge map    Save Precipitation method was used to prepare hydroxylated iron oxide (α-FeOOH) adsorbent to test its adsorption capacity for H2S using a fixed bed gas chromatography platform in this work. It was found that its sulfur capacity reached 63.8 mg/g, and the effects of O2 and H2O atmospheres on sulfur capacity were tested. It was found that there were optimal concentrations for O2 and H2O under the selected conditions, being 0.3vol% and 3vol%, respectively. The physicochemical properties of adsorbents and the occurrence forms of sulfur-containing components were characterized by XRD, XPS, TG, and CO2-TPD. It was found that the main sulfur-containing species were elemental sulfur and sulfate (SO42-) after α-FeOOH adsorbed H2S. The role of O2 in the reaction was analyzed by pre-adsorbing oxygen test. The adsorbed oxygen promoted the formation of sulfur elemental, while the presence of gaseous O2 increased the proportion of SO42-. In situ diffuse reflectance infrared spectroscopy showed the intermediate products adsorbed by H2S. H2S combined with the lattice oxygen or hydroxyl groups on α-FeOOH surface to generate HS-, and then HS- was further oxidized by Fe3+ with electron transfer to generate elemental sulfur, or HS- was oxidized by O2 to generate SO42-. This work provides a theoretical basis for the optimization of adsorbent preparation and the application of blast furnace gas purification technology. Related Articles | Metrics

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Study on stability of SiO/C slurry and semi-dry homogenization process Feng LIU Cheng LU The Chinese Journal of Process Engineering    2024, 24 (9): 1080-1087.   DOI: 10.12034/j.issn.1009-606X.223365 Abstract （466）   HTML （9）    PDF （4869KB）（201）       Knowledge map    Save Si based anode has become a research hotspot for high energy density lithium batteries due to its high specific capacity, and the preliminary production and application of SiO has been realized. The electrical performance, lifetime and consistency of lithium-ion battery are directly related to its electrode performance, and homogenization is a key process in the electrode production. The stability of SiO/C anode slurry was studied and a semi-dry homogenization process was innovatively developed. The stability of SiO/C-1 and SiO-2 with 1.6wt% and 3.1wt% of carbon was compared in aqueous slurry, and the gas production of SiO/C-1 was obvious in the water due to the fact that Si reacted with H2O to form H2 under alkaline condition, while there was no gas production of SiO/C-2, and the condition of the slurry and the electrode was better. SEM, EDS, and TEM showed that SiO/C-2 had a uniform carbon coating layer with a thickness of 20~30 nm, which can block water and improve the stability, and in the application of SiO/C, it was necessary to pay attention to the carbon coating of the material. In order to improve the stability of SiO/C anode electrode slurry to improve the homogenization efficiency, a semi-dry homogenization process was developed, through the testing of slurry solid content, viscosity, fineness, rheology, gas production and the peeling force, resistance of the electrode, SEM, as well as the cycling performance of the cell was analyzed. The results showed that the developed semi-dry homogenization process was able to achieve a high solid content of 51.8wt%, viscosity of 4900 mPa?s and fineness of 20 μm. The viscosity of the slurry was 10 000 mPa?s after 24 h, and the slurry was basically free of gas production for 48 h. The peeling force of the anode electrode was 15 N/m, and the resistivity was 0.106 Ω/cm. The high-temperature cycle life of the 330 Wh/kg pouch cell made with high-nickel NCM (Ni9) can reach 800 cycles, which was obviously superior to that of the ordinary wet homogenizing process. Related Articles | Metrics

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Design and performance study on a novel gravity heat pipe based energy storage unit for new energy consumption Shu ZHANG Yuanlin CHENG Hu YU Yi ZHANG Jinlin XIE Xingwei LIAO Ren ZHANG Changhui LIU Yanlong GU The Chinese Journal of Process Engineering    2025, 25 (4): 373-381.   DOI: 10.12034/j.issn.1009-606X.224288 Abstract （462）   HTML （12）    PDF （2378KB）（73）       Knowledge map    Save As the global climate change issue has been escalating in severity, promoting the transformation of the energy structure has emerged as an irresistible trend. This involves reducing reliance on fossil fuels and enhancing the capacity for new energy consumption, particularly in the field of building heating, which contributes significantly to overall energy consumption. In this work, a solid-liquid phase change/vapor-liquid phase change coupling-based thermal storage heating device is designed, which is essentially a combination of a new type of gravity heat pipe and the phase change material paraffin wax, supplemented by the internal and external heat dissipation fins of the heat dissipation cylinder of the heat dissipation cylinder, enabling the completion of heating through natural convection. The wall temperature characteristics, start-up characteristics, heat transfer performance, and uniform temperature performance of the designed new gravity heat pipe with square liquid cavity are investigated experimentally. Subsequently, the heat storage and release characteristics of the heating unit are studied, and it is concluded that the new gravity heat pipe has good start-up characteristics, heat transfer characteristics, and uniform temperature performance, and its minimum heat transfer thermal resistance can be as low as 0.018℃/W, and the maximum equivalent thermal conductivity is 239.15 kW/(m?℃). The minimum starting temperature is 56.9℃, and the minimum homogeneous temperature coefficient is 0.009. The heating unit has a better heating capacity, with a maximum heating coefficient of 3.83. The design and research results of this new energy storage unit have important reference value for the comprehensive utilization of mobile heating units and distributed energy. Related Articles | Metrics

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Research on Cu-assisted leaching process of zinc leaching residue and zinc calcine Limin ZHANG Yunyan WANG Weiping LIU Xiaobo MIN Wenjun LIN Yong KE The Chinese Journal of Process Engineering    2024, 24 (5): 558-565.   DOI: 10.12034/j.issn.1009-606X.223327 Abstract （456）   HTML （4）    PDF （1157KB）（171）       Knowledge map    Save To reduce the amount of zinc leaching residue and improve the metal recycling rate in the traditional zinc smelting process, a Cu-assisted reductive leaching process of zinc leaching residue and zinc calcine was proposed in this study. In the presence of sufficient copper powder, effect of factors including sulfuric acid concentration, liquid-solid ratio, leaching temperature, and the amount of H2SO4 on the zinc leaching efficiency, the residual rate of the solid, and the residual amount of H2SO4 for zinc leaching residue and zinc calcine was investigated. The results of leaching experiment showed that for zinc leaching residue, the zinc leaching efficiency was enhanced from 32.82% to 92.82% assisted by copper, compared to the pure acid leaching process (100 g/L H2SO4, 20 mL/g, 60℃). The residual rate of the solid was decreased from 62.34wt% to 25.20wt%. Values of pH of the leaching solution were increased from 0.12 to 0.36. For zinc calcine, the zinc leaching efficiency was enhanced from 86.52% to 98.82% assisted by copper, compared to the pure acid leaching process (200 g/L H2SO4, 10 mL/g, 60℃). The residual rate of the solid was decreased from 26.56wt% to 6.28wt%. Values of pH of the leaching solution were increased from 0 to 0.19. The least concentration of the residual H2SO4 was 25~26 g/L for sufficient extraction of zinc. The Cu-assisted leaching process has advantages in metal recycling, residue reduction, and low concentration of the residual H2SO4. It supplies a new idea about in situ treatment of zinc leaching residue in zinc smelters. Related Articles | Metrics

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Simulation of shape of liquid bridge and gas-liquid interface energy between two ellipsoidal wet particles Wenzhe WANG Guihuan YAO The Chinese Journal of Process Engineering    2025, 25 (4): 332-340.   DOI: 10.12034/j.issn.1009-606X.224247 Abstract （455）   HTML （18）    PDF （5086KB）（83）       Knowledge map    Save Wet particulate matter widely exists in nature, production and daily life. Surface Evolver was used to investigate the shape of liquid bridge between two ellipsoidal wet particles placed vertically and parallel to each other during the relative rotation and the effects of contact angle, rotation angle, gravity and other parameters were analyzed. Under several different contact angles, the changes in the relative angle between the two particles from 0° to 90° were observed to analyze the changes in the gas-liquid surface area, solid-liquid contact area, and the shape of the contour line obtained by intersecting the plane passing through the center line of the two particles with the surface of the liquid bridge. The differences in the contour line shape of the liquid bridge under the same relative angle with and without gravity were compared. The results showed that the shape of the liquid bridge was a rotationally symmetric body. This body did not satisfy the arc assumption. The variation of the contact angle changed the shape of the liquid bridge. The changes in rotation angle and gravity caused the profile of the liquid bridge to change. Specifically, it changed from an elliptic curve to a hyperbola. The gravity caused the contact line on the upper and lower particles to shift. The rotation of the particles resulted in the reduction of the solid-liquid interface. The gas-liquid interface area of the liquid bridge was sinusoidally related to the relative angle of the particles. The minimum volume required to maintain the liquid bridge under gravity was investigated by gradually reducing the volume of the liquid bridge, and it was shown to be quadratically related to the contact angle and to increase with the increase in liquid density, with the minimum volume required to maintain the liquid bridge when the contact angle was about 90°. Related Articles | Metrics

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Application research based on optimization of key parameters in heavy gas dispersion model Jiamei YIN Haiyan LIU Zechun LIU Wei WU Juanxia HE The Chinese Journal of Process Engineering    2024, 24 (6): 681-691.   DOI: 10.12034/j.issn.1009-606X.223272 Abstract （452）   HTML （47）    PDF （3264KB）（152）       Knowledge map    Save Leakage accidents from storage tanks with dangerous chemicals may cause catastrophic consequences. For the purpose of improving the predicted accuracy of heavy gas dispersion during release incidents, the dispersion coefficients were improved in SLAB to obtain the SLAB-D model. Then SLAB-MD model was developed by integrating the optimization algorithms of dispersion coefficients based on the SLAB-M. The Jack Rabbit II (Trials 1, 7, and 9) liquid chlorine leakage experiments were employed as the dataset to evaluate and validate models' performance. The outcomes revealed that the four models' performances were ranked as SLAB-MD>SLAB-D>SLAB-M>SLAB, and the statistical performance measurements (SPMs) of the SLAB-MD model were close to the ideal values, among which the mean relative bias (MRB), geometric mean (MG), mean relative square error (MRSE), geometric variance (VG), and factor of 2 (FAC2) were 0.27, 1.34, 0.18, 1.24, and 0.93, respectively, which proved that SLAB-MD was excellent in accurately predicting the dispersion of heavy gas leaks. Finally, the model was used to analyze three typical heavy gas leakage and dispersion accidents at domestic and international, which obtained key information such as heavy gas concentration distribution and three-dimensional concentration surface. Additionally, the range of potential casualties was predicted based on the protective action criteria values (PACs). The potential impact zones at the downwind distance, including fatalities, serious injuries, and minor injuries, were 0.15, 1.75, and 7.6 km2, 0.22, 1.98, and 7.03 km2, and 0.12×10-3, 0.29×10-3, and 0.88×10-3 km2 in the context of liquid chlorine continuous release, liquid chlorine instantaneous leakage, and vinyl chloride continuous discharge, respectively. At sensitive points, the longest escape time was 28 min for liquid chlorine continuous leakage accident, and aftereffect time was 40 min for vinyl chloride continuous release accident. In summary, these predictions provide critical information and effective technical guidance that can be used for emergency response planning and management involving hazardous chemical material spills. Related Articles | Metrics

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Multi-physical field coupling simulation study in cement rotary kiln Jing GUAN Yujie TIAN Yinjie LIU Fei LI Jiayuan YE Chengwen XU Chunxi LU Wei WANG Xianfeng HE The Chinese Journal of Process Engineering    2025, 25 (5): 445-458.   DOI: 10.12034/j.issn.1009-606X.224299 Abstract （449）   HTML （22）    PDF （4063KB）（94）       Knowledge map    Save As a key equipment in the cement production process, the combustion of gas-phase pulverized coal particles and the sintering reaction of solid-phase cement are carried out at the same time, which has a decisive impact on the generation of cement clinker products and the quality of products. However, due to the large difference in reaction rate and flow rate between the two processes, most of the existing simulations are limited to the study of a single solid-phase sintering or gas-phase pulverized coal combustion reaction process, and the interaction between the two processes is rarely discussed. In view of this shortcoming, an innovative gas-solid phase coupling simulation method was proposed, which divided the kiln area into three-dimensional gas-phase pulverized coal combustion zone and one-dimensional solid-phase cement sintering zone, which were simulated independently, and the close coupling between the two processes was realized through iterative calculation. The coupled simulation method effectively overcame the simulation challenges caused by the significant difference in flow velocity between the gas phase and the solid phase, and can more comprehensively reveal the interaction mechanism of fluid flow, heat transfer and chemical reaction in the kiln, providing a multi-scale coupled simulation method for the complex system of rotary kiln. The coupled simulation results showed that compared with the traditional single one-dimensional or three-dimensional simulation, this method can significantly improve the simulation accuracy, and the simulation results were highly consistent with the actual clinker output data of the plant. It can effectively guide the optimal design and operation process of rotary kiln, so as to improve the quality of clinker products, and provide an accurate and efficient simulation method for the simulation of cement rotary kiln. Related Articles | Metrics

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CFD-DEM-based simulation of Ca(OH)2/CaO thermochemical energy storage process in a novel baffled moving bed reactor Jianyi CHEN Min XU Cang TONG Caifeng HUANG Xiulan HUAI The Chinese Journal of Process Engineering    2024, 24 (8): 894-903.   DOI: 10.12034/j.issn.1009-606X.224048 Abstract （448）   HTML （10）    PDF （11216KB）（160）       Knowledge map    Save The Ca(OH)2/CaO thermochemical energy storage technology has garnered significant attention owing to its attractive features of high energy storage density and cost-effectiveness, positioning it as a promising advancement in energy storage methodologies. Nonetheless, traditional fixed bed reactors may pose challenges with their potential to yield a diminished heat storage rate for Ca(OH)2 particles. To address the challenge of low heat storage rate in conventional fixed bed reactor, a novel baffled moving bed structure is introduced. The heat storage process of Ca(OH)2 particles in the moving reactor bed under the influence of gravity is studied by using the coupled method of computational fluid dynamics and discrete element method (CFD-DEM). Compared to porous media models, CFD-DEM offers a closer approximation to real flow conditions and provides detailed physical information at the particle scale. The results indicate that the moving bed achieves a higher heat storage rate compared to its fixed bed counterpart under identical conditions, providing evidence for the feasibility of employing a moving bed as a thermochemical reactor. The introduction of baffles in the moving bed is able to extend the particle residence time in the reactor, consequently amplifying both the heat storage rate and energy storage efficiency. However, it concurrently results in an increased pressure drop on the gas side. The simulations under various inlet conditions reveal that elevating the gas temperature at the reactor inlet positively impacts the heat storage rate. Within specific ranges, an increase in the inlet gas flow rate can improve the energy storage rate, albeit with caution against excessively high flow rates that could induce blockages and diminish the overall heat storage rate. Notably, the inlet solid flow rate exhibits an optimum value, maximizing the comprehensive heat storage rate of the reaction bed. Related Articles | Metrics

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Study on influence of dust concentrations and moisture contents on formation characteristics of dust cake and filtration performance of coated filter media Lumin CHEN Haijin LI Chen ZHU Wenyuan HU Fuping QIAN Zhimin ZHENG The Chinese Journal of Process Engineering    2025, 25 (4): 416-424.   DOI: 10.12034/j.issn.1009-606X.224303 Abstract （447）   HTML （10）    PDF （3364KB）（64）       Knowledge map    Save In order to meet the latest national ultra-low emission standards, effective management of industrial dust is the key to achieving the goal. This study establishes an experimental test system for filter materials to investigate the influence of dust concentration and dust moisture content on the dust cake formation characteristics and filtration performance of coated filter media by analyzing the pressure drop, filtration efficiency, dust deposition per unit area, the thickness of dust cake and the standard deviation of thickness. The results show that with the extension of the filtration time, the thickness and inhomogeneity of the dust cake gradually increased from the top to the bottom in the vertical direction, however, the unevenness of the dust cake thickness stabilized after a period of time. With the increase of dust concentration, the thickness and inhomogeneity of the dust cake gradually increase. When the dust concentration is low, the overall increase in the thickness of the dust cake from the top to the bottom is slow, and the thickness difference is small. When the dust concentration is high, the thickness of the top of the dust cake increases slowly and the thickness of the bottom increases rapidly. With the increase of dust concentration, the pressure and the dust deposition per unit area increase, the filtration efficiency is around 99.9%, and the porosity gradually decreases overall. With the increase of dust moisture content, the uniformly of dust cake varies significantly, the dust cake uniformity is poor when the dust moisture content is 9% and 13%, and the distribution of dust cake is relatively uniform when the dust moisture content is 10%~12%. The effect of dust moisture content on the filtration performance is mainly reflected in the change of pressure drop, and the increase of dust moisture content helps to reduce the pressure drop of the dust cake, and the effect on the filtration efficiency is not significant. Related Articles | Metrics

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Influence and mechanism analysis of sleeve angle on cavitation characteristics of window-type sleeve control valves Kan SHENG Shenzhe ZHANG Zhijiang JIN Jinyuan QIAN The Chinese Journal of Process Engineering    2025, 25 (5): 425-434.   DOI: 10.12034/j.issn.1009-606X.224267 Abstract （445）   HTML （26）    PDF （3732KB）（90）       Knowledge map    Save As common regulators, window-type sleeve control valves are critical components in process industry systems and the core structures of the control system flow. However, the occurrence of cavitation within these valves can lead to issues such as the failure of control capabilities and the wear of the structural surfaces, which can significantly affect the normal flow regulation of the system. In the design process of window-type sleeve control valves, there are two symmetrical installation angles of the sleeve based on engineering practice. This work aims to elucidate the impact of sleeve angles on the cavitation characteristics of window-type sleeve control valves. Numerical simulation methods are employed to investigate the cavitation characteristics and the cavitation mechanisms under different sleeve angles and various operating conditions. The results indicate that changes in the sleeve angle can effectively suppress cavitation within the valve without compromising its flow capacity. Two different sleeve angles are investigated in this research. Under high-pressure drops, the maximum growth rate of the steam phase volume reached 40.29%, while the growth rate of the valve's resistance coefficient is below 5%. This finding means that adjustments to the sleeve angle can be made to minimize cavitation while maintaining the valve's flow capability. Furthermore, the research identifies two distinct mechanisms of cavitation generation within the valve: one resulting from high-speed jets due to abrupt area contractions and the Coanda effect, and the other caused by local pressure drops associated with strong vortex structures at the bottom of the throttling window. Interestingly, a direct correlation is found between the presence of these strong vortex structures and the locations where cavitation occurs. The findings of this study provide valuable insights for setting the sleeve installation angles and optimizing the design of cavitation suppression structures in window-type sleeve control valves, enhancing their performance and reliability in engineering applications. Related Articles | Metrics

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Surface structure modulation of CeO2/N-doped carbon composites and the dye removal properties Yaohua HUANG Hao ZHANG Yanqi LIU Binghui WANG Richuan RAO The Chinese Journal of Process Engineering    2025, 25 (4): 389-398.   DOI: 10.12034/j.issn.1009-606X.224210 Abstract （444）   HTML （11）    PDF （4849KB）（71）       Knowledge map    Save In this work, the surface structure of CeO2/nitrogen-doped carbon composites was tuned by controlling the feeding order of cerium nitrate and melamine in their synthesis process. Upon the characterization by TEM, XRD, TG, Zeta potential, and N2 adsorption-desorption isotherms, the synthesized CeO2/N-doped carbon composites were confirmed to be mainly composed of CeO2 and a large amount of N-doped carbon with different structures. Interestingly, it was found that the feeding order had a great influence on the nitrogen content, CeO2 dispersion, surface charge distribution, pore structure as well as specific surface area of CeO2/N-doped carbon composites. Compared to the CeO2/N-doped carbon composites prepared first by adding melamine (MCe), the CeO2/N-doped carbon composites prepared first by adding cerium nitrate (CeM) in their synthesis process had a much higher nitrogen content, which promoted the CeO2 dispersion on N-doped carbon surface and led to the formation of a predominantly positively charged surface in this sample, despite their lower specific surface area and unfavorable pore structure. The removal of Congo red by adsorption was employed to investigate the correlation between the surface structure of adsorbents and their adsorption capacities. It was discovered that the pore structure and specific surface area of CeO2/N-doped carbon composites were not the predominant factors for the adsorption removal of Congo red. Since Congo red presented an anionic state in aqueous solution, the formed Congo red anions could adsorb onto the positively charged surface of the sample via an electrostatic adsorption interaction, achieving high efficient removal of Congo red from the dye waste solution. Therefore, CeM exhibited a higher removal efficiency of Congo red. The adsorption capacities of the CeO2/N-doped carbon composites were further investigated to reveal the effect of different adsorption conditions such as inorganic salt, Congo red concentration, pH value, adsorbent dosage, and adsorption temperature. Related Articles | Metrics

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Research progress on the mechanism and influencing factors of microorganisms to increase coalbed methane production Na ZHANG Xuefeng YIN Zichen WANG Hao LIU Minjie HUANG Hao WANG Dongxu LIANG Jianan HU The Chinese Journal of Process Engineering    2024, 24 (6): 636-646.   DOI: 10.12034/j.issn.1009-606X.223310 Abstract （443）   HTML （16）    PDF （1144KB）（206）       Knowledge map    Save Microbially enhanced coalbed methane (MECBM) is an innovative technology for the extraction and utilisation of coalbed methane (CBM), which involves the microbial degradation and conversion of certain organic components of coal into methane gas. MECBM has great potential and environmental characteristics, and offers the prospect of establishing a new type of energy system, which will hopefully lead to the development of a sustainable energy source, and will effectively alleviate the challenges posed by energy shortages and greenhouse gas emissions. However, widespread application of MECBM technology faces the obstacles of historically low natural CBM production and sub-optimal quality. In order to understand the production potential of coal biogenic methane and the factors controlling the process, with a view to advancing the direction of its research towards continuous progress and effectively increasing coalbed methane production. This review summarises the mechanism and influencing factors of microbial CBM production, providing a theoretical basis for microbial CBM production. Firstly, the background and current research status of microbial production of CBM are reviewed. Subsequently, the basic theory and reaction process of coal biogenic methane production are summarised, showing that acidification of methoxy plays a decisive role in the process of coal biogenic methane production. Then, the environmental and biological factors affecting microbial enhancement of coalbed methane production are summarised, including the temperature of the coalbed, inoculum amount, nutrient addition, and pretreatment method. These factors have a significant impact on microbial CBM production, and optimising natural gas production conditions can not only increase CBM production but also significantly improve the methane concentration in CBM. In conclusion, microbial enhanced CBM technology has great potential and is expected to provide new solutions to the problems of energy shortage and greenhouse gas emissions by optimising production conditions and improving the viability and adaptability of microorganisms. Finally, this study outlines the current challenges and areas for further research in biogenic CBM development, providing a theoretical basis for increasing on-site production and enhancing CBM development. Related Articles | Metrics