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Table of Content
25 January 2025, Volume 76 Issue 1
    Reviews and monographs
    Research progress of heterogeneous catalysts for conversion of holocellulose derivatives into bio-aviation fuels
    Jijun ZOU, Baohong LIU, Chengxiang SHI, Lun PAN, Xiangwen ZHANG
    2025, 76(1):  1-17.  doi:10.11949/0438-1157.20240790
    Abstract ( 267 )   HTML ( 80)   PDF (4767KB) ( 380 )  
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    Lignocellulose is an abundant biomass resource in nature, in which hemicellulose and cellulose can be converted into two important platform chemicals—furfural and 5-hydroxymethylfurfural after hydrolysis and dehydration, and other platform chemicals can be acquired from them through hydrogenation or other methods. Carbon-carbon coupling of these platform chemicals can produce oxygenated compounds above C8, and then long-chain alkanes can be obtained through hydrodeoxygenation. After subsequent treatment, they can be used as aviation kerosene, etc. Therefore, carbon-carbon coupling and hydrodeoxygenation are the keys to the conversion of holocellulose derivatives into biofuels. In this paper, heterogeneous catalysts and their catalytic mechanisms for two important carbon chain extension reactions—aldol condensation and hydroxyalkylation/alkylation are reviewed first. The catalysts mainly include alkaline catalysts, acidic catalysts and acid-base synergistic catalysts for aldol condensation reaction, and acidic catalysts for hydroxyalkylation/alkylation reaction. Then the catalysts used in the subsequent hydrodeoxygenation process are briefly introduced, and finally the development direction of catalysts in the future is prospected.

    Influence of support on the performance of single atom electrocatalyst for ammonia synthesis and the control strategy
    Zhijiao JI, Xiaofang ZHANG, Wen GAN, Yunpeng XUE
    2025, 76(1):  18-39.  doi:10.11949/0438-1157.20240659
    Abstract ( 176 )   HTML ( 46)   PDF (11567KB) ( 367 )  
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    Electrocatalytic nitrogen reduction to ammonia (e-NRR) is a low-carbon and green ammonia synthesis method. The development of efficient electrocatalysts is the key to break the thermodynamic limitation of e-NRR and promote the technology to industrialization. The single atom catalyst has high atomic utilization and is expected to be used for e-NRR and achieve high Faradaic efficiency and ammonia yield. However, due to the high surface energy of the single atom, it is necessary to select a suitable support to stabilize the single atom site and further improve the catalytic activity by using the support metal strong interaction (SMSI). Based on the mechanism of e-NRR, this review summarizes the current synthesis methods and characterization of single atom catalysts and the application of single atom catalysts supported by different support in e-NRR. In addition, this review also concludes the optimal regulation strategy of single atom catalysts, and future analyzes the development trend of single atom catalyst in e-NRR. It is found that carbon based material loaded single atom catalysts are the most widely used, while single atom catalysts based on oxides, sulfur compounds, MXenes, and single atom alloy catalysts in the field of e-NRR are more theoretical, and there is a vast space for research and development. Building defects in the support to enhance SMSI, or building double single atoms to achieve synergistic catalysis is an effective strategy to further improve the performance of e-NRR.

    Advances in the application of carbon nanomaterials for zinc ion batteries
    Ziyi XU, Yang XI, Zewen SONG, Haijun ZHOU
    2025, 76(1):  40-52.  doi:10.11949/0438-1157.20240741
    Abstract ( 251 )   HTML ( 58)   PDF (5557KB) ( 152 )  
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    Zinc ion batteries have great potential for development in power grid and wearable devices due to their low price, excellent energy storage performance, and safety. However, zinc as a negative electrode is unstable, and zinc dendrites are easily formed on the zinc negative electrode accompanied by hydrogen evolution and side reactions, which has always been an obstacle to its widespread application. Carbon nanomaterials with excellent electrical conductivity, chemical stability and tunable surface properties have shown a wide range of applications in zinc ion batteries. This paper first briefly describes the working principle of zinc-ion batteries, and focuses on the application of carbon nanomaterials in zinc ion batteries, then summarizes the different forms of carbon nanomaterials used in zinc ion batteries and their effects on improving battery performance. It also looks forward to the potential future trends of carbon nanomaterials in the field of zinc ion batteries.

    Research progress in the synthesis of olefins by selective hydrodechlorination
    Chen YANG, Wei MAO, Xingzong DONG, Song TIAN, Fengwei ZHAO, Jian LYU
    2025, 76(1):  53-70.  doi:10.11949/0438-1157.20240701
    Abstract ( 178 )   HTML ( 39)   PDF (3351KB) ( 439 )  
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    In recent years, with the increasing consumption of aliphatic unsaturated compounds such as ethylene and propylene in modern society, the transformation of halogenated compounds to above high-value chemicals via the selective hydrodechlorination technology has attracted much attention in both of academia and industry. The core is the design and preparation of high-performance catalysts. This paper first reviews the research progress of catalysts for hydrodechlorination to olefins, focusing on summarizing the influence of the geometric structure, electronic structure, catalytic promoter, and preparation method of the active components of the catalysts such as Pd and Pt on the formation of olefins. Then, the progress of mechanism in the synthesis of olefins via catalytic selective hydrodechlorination is summarized from dynamics and theoretical calculations. Furthermore, four main reasons of catalyst deactivation are summarized. Finally, based on the structural stability of metal fluoride under high temperature and strong corrosive atmosphere such as HCl, and easily achieving interaction between supports and active components, the development of Pd-based and Pt-based supported metal fluoride catalysts is a significant rote to synthesizing olefins via the selective hydrodechlorination.

    Thermodynamics
    Research on the phase equilibrium and depressurization phase transition characteristics of liquid ammonia-refined oil mixed system
    Xin HUANG, Yilong LI, Weidong LI, Hongxiang SHI, Pengbo YIN, Zhenchao LI, Lin TENG, Lilong JIANG
    2025, 76(1):  71-80.  doi:10.11949/0438-1157.20240680
    Abstract ( 182 )   HTML ( 28)   PDF (3914KB) ( 81 )  
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    Ammonia, as an efficient hydrogen storage carrier, has great potential to replace fossil fuel energy. The use of refined oil pipelines to increase the infusion of liquid ammonia can make full use of the pipeline capacity and save transportation costs. The phase equilibrium problem of the liquid ammonia-refined oil blend system is of great significance to the pipeline transportation process, and the decompression process will cause more complex phase change problems. In this paper, the effects of ammonia/oil ratio and moisture content on the phase equilibrium and decompression phase change of the liquid ammonia-refined oil mixed system were clarified, the phase equilibrium pressure of the liquid ammonia-refined oil mixed system was obtained, and the phase change mechanism of the liquid ammonia-refined oil mixed system was revealed. It is found that the equilibrium vapor pressure of the ammonia-oil mixed system is less than the saturation vapor pressure of the two pure components in 0—30℃, and is greater than the saturation vapor pressure of pure liquid ammonia in -2—0℃, and reaches the maximum value when the oil volume ratio is 0.3. At the same time, the presence of moisture reduces the equilibrium vapor pressure of the ammonia-oil mixture. The ammonia-oil anhydrous mixed system will produce bubbles during the decompression process. The lower the pressure, the more bubbles there are, and the more intense the foaming behavior. The aqueous liquid ammonia-oil mixing system generates droplet clusters during decompression, which slowly become larger and aggregate, and form large droplets that remain at the bottom at the end of decompression. The above research results have important theoretical guiding significance for the development and application of ammonia infusion technology in refined oil pipelines.

    Prediction and verification of calcium sulfate scaling trend in hydrothermal desalination process of high salinity mine
    Yuanhui TANG, Yuanji BAI, Qiang GUO, Xiaolei HE, Lixin YU, Yakai LIN, Xiaolin WANG
    2025, 76(1):  81-92.  doi:10.11949/0438-1157.20240417
    Abstract ( 154 )   HTML ( 21)   PDF (3119KB) ( 49 )  
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    The highly mineralized mine water is characterized by its complex composition, high salinity, and significant hardness, which leads to the formation of inorganic scales during thermal desalination processes, primarily composed of CaSO₄. Based on the typical composition of highly mineralized mine water, a simulated feed solution containing Ca²⁺, Mg²⁺, Na⁺, Cl⁻, and SO42- was prepared. The solubility of CaSO₄ in the Ca²⁺-Mg²⁺-Na⁺-Cl⁻-SO42- system was then investigated using an isothermal dissolution method at temperatures of 40, 50, 60, and 70℃. The results indicate that within the temperature range of 40℃ to 70℃, the solubility of CaSO₄ decreases with increasing temperature, increases with higher MgCl2 concentration, and decreases with higher Na2SO₄ concentration. The Oddo-Tomson saturation index method was used to predict the scaling trend of CaSO4 in the thermal desalination process, and the modified saturation index (SI) equation was obtained. The prediction results of this equation are consistent with the scaling experiment of CaSO4 on the surface of stainless steel pipe at 65℃. When the saturation index exceeded 0.2, CaSO₄ crystals began to precipitate on the surface of stainless steel tubes in the Ca²⁺-Mg²⁺-Na⁺-Cl⁻-SO42- system. Finally, scaling experiments using simulated high-mineralized mine water SA and SB were employed to demonstrate the feasibility and limitations of this method in practical mine water applications.

    Predicting and interpreting the toxicity of ionic liquids using graph neural network
    Haijun FENG, Bingxuan ZHANG, Jian ZHOU
    2025, 76(1):  93-106.  doi:10.11949/0438-1157.20240663
    Abstract ( 149 )   HTML ( 12)   PDF (4371KB) ( 222 )  
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    Ionic liquids are potentially toxic to the environment, how to control the toxicity of ionic liquids is one of the key factors. To understand their toxicity mechanisms, three traditional machine learning methods (support vector machine, random forest, multilayer perceptron) and three graph neural network models (graph attention network, message passing neural network, graph convolutional model) were established to predict the toxicity of ionic liquids in four living organisms (leukemia rat cell line IPC-81, acetylcholinesterase, Escherichia coli, and Vibrio fischeri). The simplified molecular-input line-entry system (SMILES) of molecules and toxicity lgEC50 values work as the input and output respectively. In the three traditional machine learning methods, extended-connectivity fingerprints (ECFPs) were used to represent molecules. While in the three graph neural network models, molecular graphs were used to represent molecules. Benefiting from molecular structure information, the graph convolutional model (GCM) had lower RMSE and MAE, and higher R2 than other models in all four datasets. Therefore, the GCM model was superior in predicting the toxicity of ionic liquids. Meanwhile, based on the GCM model, an intepretability model was established to analyze the contribution of atomic groups to the toxicity of ionic liquids in a data-driven procedure. The aromatic ring of cations and long alkyl chain could produce toxicity. Atomic groups such as S+, P+, N+, and NH+ could significantly enhance the toxicity of ionic liquids, while atomic groups such as P-, F, B-, and C could effectively reduce the toxicity of ionic liquids. This discovery provides a theoretical basis for rapid screening and development of greener and low-toxicity ionic liquids.

    Molecular mechanism analysis of melanoidin adsorption by polyamine-modified chitosan aerogel based on multiple quantum chemical theory calculations
    Jiaxin WANG, Yanhong WEI, Shunyang NONG, Yanshu XIONG, Mei LI, Wen LI
    2025, 76(1):  107-119.  doi:10.11949/0438-1157.20240584
    Abstract ( 108 )   HTML ( 17)   PDF (10263KB) ( 328 )  
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    Existing sugar juice decolorizers have food safety hazards and low adsorption capacity. To address these issues, we have developed a green, non-toxic, and efficient hyperbranched polyethyleneimine-functionalized chitosan aerogel (HPCA) for sugar juice decolorization and conducted preliminary investigations into its ability to adsorb melanoidin (MLD) from sugar juice. However, it is necessary to further explore the theoretical mechanisms of adsorption in order to apply efficient HPCA to industrial settings. In this study, we systematically investigated the potential mechanisms of MLD adsorption by HPCA from a molecular perspective using multiple quantum chemical theoretical calculations. Our findings on the electrostatic potential, average local ionization energy, and electrostatic potential interactions suggested that MLD capture by HPCA was primarily mediated by the charge interaction between protonated amine group on HPCA and carboxylate group on MLD. Three visualized optimal capture configurations were proposed at the molecular level, with Configuration I demonstrating the highest stability due to the strong electrostatic interactions formed from the close contact between HPCA and MLD. Frontier molecular orbitals, independent gradient model, and Hirshfeld surface analysis revealed that the MLD adsorption by HPCA involved weak interactions, such as hydrogen bond and van der Waals force. Notably, the MLD mainly acted as hydrogen bond receptor in various capture configurations. These multiple quantum chemical theory calculations provide valuable insights into the molecular-level mechanisms of adsorption and are significant for advancing the study of adsorption micro-mechanisms.

    Isothermal evaporation salt-forming regions of the ternary water-salt systems K+(Mg2+), Ca2+//Cl--H2O
    Lingyu LI, Xin HU, Huaigang CHENG, Yun ZHAO, Dong AN, Yujun MA, Jiahao JIN, Xudong YU, Weidong ZHANG
    2025, 76(1):  120-130.  doi:10.11949/0438-1157.20240597
    Abstract ( 106 )   HTML ( 7)   PDF (2169KB) ( 314 )  
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    Based on the traditional experimental method of isothermal evaporation metastable phase diagram of ternary water-salt system, a slight improvement was made. Experimental study was carried out by taking two ternary systems of K+(Mg2+), Ca2+//Cl--H2O as examples. The key experimental steps of the new method are: isothermal evaporation starts from the selected unsaturated solution point; as the evaporation process progresses, grasp the moment before the solid precipitates; before the solid precipitates but is about to precipitate, take out the supersaturated liquid phase and measure its solubility; then construct an isothermal evaporation supersaturation phase diagram. During the experimental process, the liquid phase is in a supersaturated state but not in the phase equilibrium, so the rule of phase equilibrium is not obeyed. Thereby, the two-salt co-saturation of the two ternary systems has changed from the point in the stable phase equilibrium diagrams to the two-salt co-saturation line in the supersaturation phase diagrams obtained by the new experimental method proposed in this paper. Therefore, for the phase diagram formed by the new experimental method, it should not be referred to as the metastable phase equilibrium diagram, but can only be referred to as the supersaturated solubility diagram. By combining the stable phase diagram with the supersaturated phase diagram obtained from the new experimental method, the thermodynamic non-equilibrium phase diagram is drawn. And the salt-forming phase region is obtained for the isothermal evaporation process of ternary system, and thus the supersaturation limits for the actual isothermal evaporation process are given. The comparative experiments for the two ternary systems K+(Mg2+), Ca2+//Cl--H2O were conducted using the traditional metastable experimental method, which confirm that the random metastable solubility curves obtained by the traditional experimental method always fall within the salt-forming phase region obtained based on the new experimental method.

    Fluid dynamics and transport phenomena
    Experimental investigation on spray cooling heat transfer enhancement by n-pentanol additive
    Han CHEN, Chang CAI, Hong LIU, Hongchao YIN
    2025, 76(1):  131-140.  doi:10.11949/0438-1157.20240641
    Abstract ( 98 )   HTML ( 12)   PDF (2720KB) ( 346 )  
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    Spray cooling is a promising heat dissipation technique for the thermal management of high-power devices. In the present research, pure water and bi-component mixtures with low concentrations of n-pentanol are adopted as the working fluid to ascertain the additive effect. Spray cooling heat transfer characteristics are experimentally investigated, and the radial distributions of Sauter mean diameter (SMD) and droplet number are measured by the particle/droplet imaging analysis (PDIA) system, while the fluid volumetric flux distribution is measured by the self-designed precision mobile experiment bench. The results show that a small amount of n-pentanol additive can significantly improve the heat transfer performance of pure water spray cooling, but the enhanced heat transfer effect first increases and then weakens as the concentration of n-pentanol increases. Measurement shows that the SMD decreases and the droplet number increases monotonously with the n-pentanol volume fraction. The effect of n-pentanol concentration on the fluid volumetric flux is similar to that on the heat transfer coefficient, i.e., the elevation is the most obvious with the 1% (vol) n-pentanol-water mixture. It is speculated that a smaller SMD, a larger droplet number and a higher volumetric flux caused by the n-pentanol additive significantly enhance both convection and phase change heat transfer. However, since the latent heat of evaporation of n-pentanol is much lower than water, as well as the lower volumetric flux with 2.0% (vol) n-pentanol, the heat transfer enhancement effect weakens at a higher n-pentanol concentration, achieving a peak at the n-pentanol concentration of 1.0% (vol).

    Gas-liquid two-phase flow and erosion-corrosion in air cooler of hydrogenation unit
    Yan LI, Hongli GUO, Guoqing SU, Jianwen ZHANG
    2025, 76(1):  141-150.  doi:10.11949/0438-1157.20240765
    Abstract ( 104 )   HTML ( 9)   PDF (5123KB) ( 43 )  
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    Air coolers are important heat exchange equipment in the hydrogenation process. The problem of service time far lower than the design life due to corrosion and leakage of tube bundles is common, and its failure mechanism needs to be further explored. A multiphase flow numerical simulation was carried out to investigate the corrosion and leakage of tube bundles in the top air cooler of a fractionation tower in a petrochemical plant. The results show that the complex flow field distribution is the main cause of leakage in air cooler tube bundles. Specifically, the presence of vortices inside the tube box results in varying velocities, fluid-wall impact angles, and gas-liquid two phase distributions within the tube bundle, which is an important reason leading to the uneven distribution of the leaking tube bundle of the air cooler. The actual leakage tube bundle as an example of corrosion analysis, the results show that the impact angle and liquid phase distribution is the key factor affecting the erosion-corrosion, and gas-liquid two-phase erosion-corrosion is the root cause of the leakage of the tube bundle. Finally, the erosion-corrosion mechanism of the air cooler is proposed from the perspective of multiphase flow according to the research results.

    Local deposition characteristics of CaCO3 fouling under different roughness element structures
    Zhimin HAN, Xiangyu ZHOU, Hongyu ZHANG, Zhiming XU
    2025, 76(1):  151-160.  doi:10.11949/0438-1157.20240677
    Abstract ( 84 )   HTML ( 5)   PDF (3658KB) ( 349 )  
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    Due to the fact that the heat exchange wall surface is not absolutely smooth during the actual heat exchange process of the heat exchanger, and the rough heat exchange wall surface is easy to foul at some local locations. Therefore, based on the constructed local crystallization fouling model, the local deposition characteristics of CaCO3 fouling under different roughness element structures are numerically simulated in this study. The roughness elements of three different shapes (rectangular, trapezoidal and triangular) are compared, and the influence of the relative height and relative width of the triangular roughness element is analyzed in detail. The results show that the average value of local fouling resistance in the three roughness element channels is smaller than that in the smooth channel, and the average value of local fouling resistance in the triangular roughness element is the smallest. The local fouling resistance of the three roughness element channels changes periodically along the channel length, and there are peaks in each cycle, and the maximum peak is located on the leeward side of the roughness element. In addition, the local fouling resistance decreases with the increase of the relative height of the triangular roughness element, and increases slightly with the increase of the relative width, indicating that the relative height has a greater influence on the local fouling deposition.

    Pore-scale study of effects of preferential path on multiphase reactive transport process in porous media
    Chuangde ZHANG, Li CHEN
    2025, 76(1):  161-172.  doi:10.11949/0438-1157.20240809
    Abstract ( 126 )   HTML ( 12)   PDF (8001KB) ( 92 )  
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    The multiple coupled reactive transport process of multiphase flow-solute transport-chemical reaction-solid phase evolution in porous media is crucial for many scientific and engineering problems. In this paper, a pore-scale multiphase reactive transport model is established to study the influence of preferential path on the multiphase reactive transport process in porous media. The results show that compared with the single-phase reaction transport process, where the wormhole extends along the preferential path, the presence of two-phase flow changes the mass transfer path. When the non-reactive fluid increases, the preferential path is blocked by the non-reactive fluid and the transverse mass transfer is limited, resulting in the absence of wormhole dissolution, and the delay of solid dissolution breakthrough. In addition, the existence of the two-phase stream will reduce the length of the reaction interface, and the average reactant concentration will increase significantly after dissolving breakthroughs.

    Numerical study of influence of channel vibration frequency on flow and heat transfer of supercritical n-decane with pyrolysis reaction
    Na HUANG, Yunlong JIANG, Donghan WANG, Mingting WU, Xueli JIANG, Yu ZHONG
    2025, 76(1):  173-183.  doi:10.11949/0438-1157.20240815
    Abstract ( 85 )   HTML ( 6)   PDF (5744KB) ( 266 )  
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    The pyrolysis endothermic flow process of supercritical n-decane in the vibration cooling channel is very complicated due to the coupling of multiple physical fields including flow field, temperature field and physical property field. Based on the total package reaction model of n-decane cracking, a numerical study was conducted on the flow heat transfer process of supercritical n-decane cracking in a rectangular vibration channel, and the influence of channel vibration frequency on the flow heat transfer performance of the regeneration cooling channel and its mechanism were systematically discussed. The calculation results show that the channel vibration will strengthen the internal fluid mixing, the secondary flow in the channel will increase with the increase of vibration frequency, and the lateral shear caused by high frequency vibration will disturb the fluid boundary layer, thinning the boundary layer near the wall of the hot side, and strengthening the physical heat transfer process of the hot wall. However, the enhanced physical heat transfer reduces the n-decane temperature on the hot wall surface, delaying the n-decane cracking reaction and the release of chemical heat sink. Under different vibration frequencies, the cracking reaction starts at L/D>100, and reaches the highest cracking reaction rate at L/D=130. Compared with the static channel, the surface temperature, heat transfer coefficient and mass fraction of n-decane on the hot wall surface of the vibrating channel have different characteristics of periodic distribution. The research results can provide reference for the flow heat transfer problem involving chemical endothermic reaction in the movement channel.

    Heat transfer and flow characteristics of nanofluids in microchannels
    Ping LIU, Yusheng QIU, Shijing LI, Ruiqi SUN, Chen SHEN
    2025, 76(1):  184-197.  doi:10.11949/0438-1157.20240582
    Abstract ( 198 )   HTML ( 8)   PDF (6554KB) ( 227 )  
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    In order to improve the heat transfer efficiency of microchannel heat sink, it is necessary to optimize the structure of microchannel. Taking thermal resistance Rt and pump power Pp as the objective function, under the condition of Re = 100, the multi-objective genetic algorithm is used to optimize the structural parameters of the Venturi microchannel, such as channel depth, contraction angle, throat width and diffusion angle. The Pareto optimal solution set is obtained by genetic iteration calculation, and the optimal solution set is compared and analyzed by k-means clustering method. The comprehensive performance of each clustering point is evaluated by the enhanced heat transfer factor η, and the optimal microchannel structure is obtained. The flow and heat transfer characteristics of the optimized microchannel structure were studied by numerical simulation. The results show that when nanoparticles are added to deionized water, the pressure drop in the microchannel increases slightly, but its flow resistance does not change significantly under the same Reynolds number. The throat effect will be generated at the throat position of the Venturi microchannel to strengthen the fusion of nanoparticles and the flowing working fluid in the microchannel. The entropy generation analysis shows that the heat transfer entropy decreases with the increase of Reynolds number, and the friction entropy increases with the increase of Reynolds number, but the total entropy is mainly dominated by heat transfer entropy. With the increase of volume fraction, the irreversible loss of nanofluids is less than that of deionized water.

    Mixing in a partially-filled screw channel of a baffled non-twin screw using the moving-particle semi-implicit method
    Peizhou DONG, Huiwen YU, Lingcao TAN, Baiping XU, Fang YANG
    2025, 76(1):  198-207.  doi:10.11949/0438-1157.20240673
    Abstract ( 87 )   HTML ( 6)   PDF (6319KB) ( 354 )  
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    In order to improve the mixing ability of traditional twin-screw extruders, a new type of baffled twin-screw extruder is proposed. The unique baffle structure can act on the mixing of materials, but the flow and mixing characteristics under the non-filled state are still unclear. The two-phase interface between the viscous fluid and air in the partially filled transport state is investigated by using the moving-particle semi-implicit method (MPS). The corresponding visualization experiments are conducted by using self-developed extrusion equipment with a totally transparent barrel. The distributions of velocity and pressure of the viscoelastic fluid were solved, and a self-programmed procedure are utilized to calculate the Euclidean spacing and finite time Lyapunov exponents (FTLE) of the particles to characterize the distributive mixing of the baffled non-twin screw (BTSE). The results show that the numerically simulated free interfaces are consistent with the experimental results, confirming the validity of the MPS. The particle tracking results show that in TSE the fluid particles far away from the intermeshing zone are obviously prone to aggregate together, resulting in a larger mean value of the Euclidean spacing and smaller average FTLE. Compared to the traditional TSE, BTSE generates larger values of Euclidean spacing and average FTLE, indicating that the latter is superior in distributive mixing.

    Influence of droplet merging and jumping by dual-groove structures on superhydrophobic surfaces
    Xianming GAO, Wenxuan YANG, Shaohui LU, Xiaosong REN, Fangcai LU
    2025, 76(1):  208-220.  doi:10.11949/0438-1157.20240774
    Abstract ( 116 )   HTML ( 8)   PDF (4288KB) ( 37 )  
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    Droplet jumping phenomena on superhydrophobic surfaces hold high application value in efficient heat dissipation, corrosion resistance, anti-icing, and other fields on chips. To investigate the influence of dual-groove channels on droplet jumping performance, various W-shaped groove superhydrophobic surfaces composed of dual V-grooves were designed and fabricated. The effects of the groove bottom spacing w and the groove depth h of the W-shaped groove on the bouncing velocity and energy conversion efficiency of the droplet were investigated experimentally. Numerical simulations were employed to study the evolution of surface energy during droplet merging and jumping on W-shaped groove superhydrophobic surfaces. The results show that the radius of droplets adapted to the W-shaped groove with a groove width of 0.9 mm is 0.5—0.9 mm, and the effect of droplet merging and jumping is more significant in this range when the groove depth h is 0.5—0.8 mm, and the groove bottom spacing w is 0.5—0.8 mm. As the radius of the droplet decreases, the depth of the channel increases, and the distance between the bottom of the channel decreases, the bouncing velocity increases. The bouncing velocity increased when the groove parameter was increased simultaneously within 0.5—0.7 mm and decreased at 0.8 mm. The results lay a theoretical foundation for surface design in the fields of condensation heat transfer and corrosion prevention.

    Catalysis, kinetics and reactors
    Desorption performance analysis of a metal hydride reactor with novel corrugated fins based on finite element method
    Hanbin WANG, Shuai HU, Fenglei BI, Junsen LI, Laibin HE
    2025, 76(1):  221-230.  doi:10.11949/0438-1157.20240775
    Abstract ( 108 )   HTML ( 9)   PDF (4031KB) ( 216 )  
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    Novel metal hydride reactors with corrugated fins were proposed for the efficient hydrogen release in the field of clean energy technology. Through reliable finite element numerical simulation, the influence of heat exchange fin structure parameters and heat exchange fluid flow rate on the reactor hydrogen release time is obtained. The results show that the desorption rate and heat transfer in reactor can be simulated accurately using the finite element model. The optimized reactor with 5 mm fin height, 2 mm fin length, 13 fins was obtained, and the hydrogen desorption time for 0.1% (mass) storage capacity is 24% shorter than that of the conventional circular fin reactor. When the Reynolds number of heat transfer fluid increases from 1780 to 11860, the saturation time of hydrogen discharge decreases from 930 s to 700 s. In addition, corrugated fins are easy to be manufactured and have great potential for industrial applications.

    Synthesis of a high-efficacy medium-entropy alloy catalyst via the recycling of spent batteries and its subsequent performance evaluation
    Shan GUO, Yu TIAN, Yongbin XU, Peng WANG, Zhiming LIU
    2025, 76(1):  231-240.  doi:10.11949/0438-1157.20240629
    Abstract ( 136 )   HTML ( 7)   PDF (8414KB) ( 328 )  
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    Car electrification is a green and healthy way of contemporary travel, reducing exhaust emissions while avoiding excessive consumption of fossil fuels, but the generated waste power batteries will also pose a great threat to society. Nickels, cobalt, manganese (NCM) were recovered from waste ternary lithium-ion batteries and then were alloyed with palladium. The nitrogen carbon matrix supported palladium-nickel-cobalt-manganese medium-entropy alloy nanoparticles (Pd MEA@N-C) were prepared by rapid high-temperature bombardment as double-function catalysts for lithium-oxygen batteries, so as to realize the recycling of waste ternary lithium-ion batteries. The reversible formation and decomposition of lithium peroxide (Li2O2) as a discharge product in the oxygen reduction/precipitation process (ORR/OER) was optimized. XRD and TEM showed that the Pd MEA was formed successfully, and XPS showed that the introduction of Pd was conducive to the accurate regulation of electron configuration in alloy particles. The performance of lithium-oxygen batteries assembled with Pd MEA@N-C as the positive electrode material is tested. The results show that under the conditions of limiting the capacity to 1000 mAh·g-1 and the current density to 200 mA·g-1, the overpotential was as low as 0.49 V. The deep charge and discharge test was carried out at the current density of 200 mA·g-1, and the charge and discharge capacity was 15491 mAh·g-1, which remained stable after 82 cycles.

    Process system engineering
    Detailed design of shell-and-tube heat exchanger using intelligent evolutionary algorithms
    Haidong LI, Qiqi ZHANG, Lu YANG, Naeem AKRAM, Chenglin CHANG, Wenlong MO, Weifeng SHEN
    2025, 76(1):  241-255.  doi:10.11949/0438-1157.20240761
    Abstract ( 153 )   HTML ( 10)   PDF (6909KB) ( 332 )  
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    The shell heat exchanger is the most widely used calorie recovery equipment in the process of oil, chemical industry, etc., and its mathematical models are usually very complicated non-linear optimization problems. The existing commercial solution device and optimization algorithm have long computing time, and the computing time is long. It is difficult to converge and easily fall into part of the optimal problem. In order to address these challenges, this research draws inspiration from the manufacturing norms of shell-and-tube heat exchangers. It delineates the dimensions of the internal components of heat exchangers as discrete variables and formulates a mixed integer nonlinear programming model for the intricate design of shell-and-tube heat exchangers. The model aims to minimize heat transfer area, annual total cost, environmental impact factor, and maximize heat transfer efficiency. At the same time, enhancements have been made to the traditional intelligent evolutionary algorithm, which includes the genetic algorithm, particle swarm optimization algorithm, and simulated annealing algorithm. This allows for the selection of design variables for the heat exchanger from a range of discrete values, eliminating the need for manual rounding of optimization results. Test results demonstrate that the enhanced intelligent evolutionary algorithm can achieve the optimal design solution within 1.0 s, reducing optimization time by over 99% compared to the global solver and enhancing optimization solution efficiency. Compared to the local solver, the enhanced intelligent evolution algorithm can achieve the global optimal solution, reduce heat transfer area by 15.4%—56.6%, lower annual total cost by 15.8%—77.8%, and guarantee design quality. Furthermore, multi-objective optimization is utilized to balance different objective functions, while sensitivity analysis results illustrate the impact of various design variables on the objective functions.

    Event-time triggered slow time-varying industrial process dynamic scheduling method
    Chao REN, Kai WANG, Jie HAN, Chunhua YANG
    2025, 76(1):  256-265.  doi:10.11949/0438-1157.20240784
    Abstract ( 89 )   HTML ( 4)   PDF (1842KB) ( 182 )  
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    In process industries, the phenomenon of slow time-varying transitions is prevalent. Continuous changes in operating conditions will lead to shifts in the optimal operating conditions for production scheduling, rendering original decision schemes inapplicable. Therefore, in this paper, a dynamic scheduling method based on event-time triggering mechanism is proposed. First, the impact of slow time-varying parameters on long-term scheduling decisions is analyzed. A strategy is proposed to characterize equipment performance degradation through changes in operational variables, and a dynamic triggering function is constructed. The dynamic scheduling trigger conditions integrate event and time-triggered characteristics, incorporating time-varying constraints. Secondly, dynamic information of the production system is embedded in the scheduling process. A process transition model is established as a simplified expression of input-output dynamics, thereby reducing computational complexity. Finally, a dynamic scheduling framework of closed -loop rolling is used to update the scheduling model according to the real-time operating status. In the case study, the proposed method is validated using an industrial heat exchanger network. This method provides timely dynamic scheduling, demonstrates good economic performance, and offers a new solution for production scheduling problems considering slow time-varying operating conditions.

    Mooney viscosity prediction modeling based on fusion Transformer
    Ye YANG, Jiangang LU
    2025, 76(1):  266-282.  doi:10.11949/0438-1157.20240708
    Abstract ( 51 )   HTML ( 5)   PDF (6004KB) ( 12 )  
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    Accurate prediction of Mooney viscosity is a key link in optimizing rubber mixing process, which helps to timely control rubber quality in rubber tire production process. To this end, a Mooney viscosity prediction model based on fusion Transformer (Fusformer) is proposed to conduct targeted modeling of time series variables and static covariates data generated by rubber mixing, extract and fuse various data features, and accurately predict Mooney viscosity. For time series variables, the model introduces the concept of directed graph, proposes relative position perception layer and relative multi-head attention mechanism to fully capture time series dependency features; for static covariates, the model introduces gated linear units and proposes static feature enrichment module to extract effective static features, and finally fuses time series dependency features with effective static features and outputs predicted values. The experiment uses 200000 actual samples from a rubber factory to test the prediction performance of the model, and demonstrates the rationality of the model design through comparative experiments, ablation analysis and parameter sensitivity analysis.

    Research on temperature forecasting of polyester fiber esterification process based on federated learning
    Shaoji WANG, Kuangrong HAO, Lei CHEN
    2025, 76(1):  283-295.  doi:10.11949/0438-1157.20240689
    Abstract ( 77 )   HTML ( 5)   PDF (4915KB) ( 238 )  
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    In the production process of polyester fiber, accurate control of esterification temperature is crucial. However, due to the differences in production equipment and process parameters, traditional prediction methods are difficult to meet personalized needs, and there are privacy leakage and communication pressure problems in the data sharing process. The federated personalized adaptive time series forecast algorithm on esterification temperature is proposed, which protects privacy and reduces data communication pressure. Introducing a joint forecasting mechanism, the algorithm assigns private and shared models to each client, integrates model forecasting with learnable weights to enhance forecasting accuracy and generalization capability. An adaptive stage adjusts model parameters intelligently based on client data distribution and learns unique joint forecasting weights for each client to obtain personalized forecasting outputs. In addition, the adoption of Bayesian optimization algorithms over traditional methods like random search and grid search addresses issues related to high dimensionality, complexity, and resource constraints. This approach enables rapid identification of the optimal hyperparameter combinations for various algorithms. Experiments comparing the proposed algorithm with seven federated algorithms using real raw data collected from the distributed control systems of three domestic polyester fiber manufacturers show that the forecasting performance of the algorithm in this study excels across five different forecasting models. The proposed algorithm can provide support for newly established factories, reduce their production debugging costs, enhance production efficiency and product quality, and promote the intelligent development of the industry.

    Surface and interface engineering
    Analysis and optimization of dynamic performance of super-elliptical hole floating seal dam compliant foil face gas seal
    Junjie ZHANG, Yuan CHEN, Yuntang LI, Xiaolu LI, Bingqing WANG, Xudong PENG
    2025, 76(1):  296-310.  doi:10.11949/0438-1157.20240657
    Abstract ( 84 )   HTML ( 7)   PDF (7166KB) ( 28 )  
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    To improve the opening and sealing performance of compliant foil face gas seal (CFFGS) during dynamic operation and to reduce the requirement for foil installation accuracy, a novel super-elliptical hole floating seal dam compliant foil face gas seal (SHFSD-CFFGS) structure is proposed. Unlike traditional CFFGS, SHFSD-CFFGS features super-elliptical hole textures in both the foil and sealing dam areas, with additional compliant bump foil support at the bottom of the sealing dam to form a floating dam area. Based on gas lubrication and dynamic theory, an aeroelastic coupling dynamic model of SHFSD-CFFGS is established and solved using direct numerical simulation. The dynamic performances of SHFSD-CFFGS and non-textured CFFGS are compared and analyzed, revealing the mechanisms by which super-elliptical hole textures enhance the dynamic performance of the seal. Simultaneously, aiming to increase the dynamic average opening force and reduce the dynamic average leakage rate of the SHFSD-CFFGS, an optimization design is conducted for super-elliptical texture and mechanical structure parameters. The results show that the super-elliptical hole texture in the slope area and floating dam area of SHFSD-CFFGS foil can produce secondary dynamic pressure effect and upstream pumping effect, which is helpful to improve the seal opening and sealing performance. Under the working conditions of this paper, when the super-elliptical coefficient n2 of the floating dam area is set to 1, the inclination angles ϕ1 and ϕ2 of the inner and outer holes are both between 20° and 40°, the texture depth Td2 ranges from 4 μm to 6 μm, the slender ratio γ varies from 1.75 to 2.25, the compliance coefficient α2 of the floating dam area ranges from 5×10-5 to 1×10-4, the static ring mass ms is between 0.1 kg and 0.2 kg, the spring stiffness ks ranges from 9×107 N·m-1 to 1×108 N·m-1 and the auxiliary sealing ring damping cz ranges from 9×103 N·s·m-1 to 1×104 N·s·m-1, SHFSD-CFFGS demonstrates superior comprehensive dynamic performance. These findings provide a valuable reference for the optimized design of the dynamic performance of CFFGS.

    Disturbance performance of dynamic and static pressure hybrid gas isolation seal of high-speed turbopumps
    Shuangxi LI, An LIU, Zhiyuan LIU, Jiangteng ZHANG, Shicong LI
    2025, 76(1):  311-323.  doi:10.11949/0438-1157.20240760
    Abstract ( 74 )   HTML ( 5)   PDF (5058KB) ( 12 )  
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    The isolation seal is extremely important for high speed turbine pump fuel seals, but it has problems such as gas supply pressure fluctuations and strong external vibration at work, which will seriously affect the sealing performance. Any compromise in these areas could have a detrimental impact on the sealing performance. Accordingly, the conditions for disturbance of the dynamic and static pressure isolation seal gas membrane have been established on the basis of a finite element numerical analysis. A dynamic change of disturbance analysis model has been constructed by using Fluent dynamic mesh technology and MATLAB to solve the end face gas membrane disturbance stiffness and disturbance damping. This has been compared with the static pressure and dynamic and static pressure. The mixed gas isolation seal disturbance performance has been discussed in terms of the gas membrane thickness, working pressure and disturbance amplitude, and other parameters. The influence of the gas film thickness and perturbation amplitude on the perturbation performance has been investigated, and a rule of change has been established. Finally, the anti-perturbation performance of dynamic and static pressure seals has been tested and verified. The results indicate that an increase in perturbation frequency leads to a decrease in overall perturbation stiffness, which then increases. Additionally, perturbation damping decreases rapidly with the increase in perturbation frequency, reaching a stable value between 10 Hz and 100 Hz. The supply pressure of gas is found to be positively correlated with both the stiffness and damping of the perturbation. As the speed increases, the stiffness of the perturbation increases in the low-frequency band and decreases in the middle and high-frequency bands. The damping decreases across the entire frequency spectrum. As the perturbation amplitude is increased, the perturbation stiffness remains almost unchanged in the middle and low frequency bands, while it decreases in the high frequency band. The perturbation damping increases slightly, while the working film thickness is negatively correlated with the perturbation stiffness and the perturbation damping. Hybrid dynamic and static pressure seals effectively improve the stability of the sealing device in low frequency, avoiding the problem of insufficient anti-disturbance ability when the seal is in low pressure and low speed.

    Intelligent optimization and deformation analysis of novel flexible dam foil face gas seal
    Yushi LI, Yuan CHEN, Yuntang LI, Xudong PENG, Bingqing WANG, Xiaolu LI
    2025, 76(1):  324-334.  doi:10.11949/0438-1157.20240748
    Abstract ( 78 )   HTML ( 3)   PDF (4479KB) ( 228 )  
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    A novel foil face gas seal structure with flexible seal dam is proposed. Based on the theories of gas lubrication and elastic mechanics, a theoretical model of aeroelastic coupling lubrication for the new flexible seal dam gas film seal is established. The pressure and deformation distribution of the gas film on the sealing end-face are analyzed to explore the sealing operation mechanism. The influence of working conditions and end-face structural parameters on the sealing performance is studied. The Latin hypercube sampling method is used to randomly sample key influencing factors, and an optimization model based on the MLP neural network and genetic algorithm is constructed to obtain the parameter optimization range that satisfies the objective function. The results show that the new flexible seal dam gas film seal can further improve adaptive operation capability through the deformation coordination of the sealing dam. The gap between the fan-shaped flat foil of the flexible sealing dam will increase the leakage of the seal, but the fluid dynamic pressure effect formed by the gap is conducive to the opening of the end surface. The MLP neural network-genetic algorithm optimization model can accurately predict sealing performance and effectively improve optimization accuracy and efficiency under multi-parameter and multi-objective conditions.

    Energy and environmental engineering
    Microtube structure impacts on hydrogen-air mixing effect and combustion performance in micromix combustor
    Zhicheng DENG, Huan YANG, Simin WANG, Jiarui WANG
    2025, 76(1):  335-347.  doi:10.11949/0438-1157.20240563
    Abstract ( 127 )   HTML ( 9)   PDF (5493KB) ( 50 )  
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    Due to the low density and the high adiabatic combustion temperature of hydrogen fuel, issues such as poor fuel-air mixing and high localized thermal NO x formation arise in the combustion chamber. To address these problems, a numerical simulation employing the GRI-Mech 3.0 mechanism combined with the FGM combustion model was conducted. And the effects of the equivalence ratios, the air tube diameters, the fuel tube diameters and the spoiler structures on the mixing characteristics and the combustion performance are considered. The results of the study indicate that an increase in the diameter of the air pipe is not conducive to the complete mixing of fuel and air. Furthermore, the NO emission increases by 13 times after the air tube diameter is tripled in the lean combustion condition with an equivalence ratio of 0.4. After the fuel pipe diameter increased from 0.20 mm to 0.65 mm, the hydrogen jet depth at each equivalence ratio decreased by more than 30%, the fuel-air mixing effect became worse, and the anchored flame turned into a lifting flame. Increasing the equivalence ratios raises flame temperatures and diminishes the effectiveness of NO x control, particularly with smaller air or fuel tube diameters. The spoiler structure strengthens the premixing process of fuel and air, improves the temperature uniformity of the combustion chamber and reduces the NO x generation. Among the structures studied, structure B exhibits superior mixing optimization and combustion characteristics.

    Process conditions optimization and degradation mechanism of dye wastewater by Fe0/H2O2 system using response surface methodology
    Yanping JIA, Yanju MA, Wenxin GUAN, Bin YANG, Jian ZHANG, Lanhe ZHANG
    2025, 76(1):  348-362.  doi:10.11949/0438-1157.20240492
    Abstract ( 85 )   HTML ( 9)   PDF (6990KB) ( 25 )  
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    Dye wastewater has the characteristics of large coloring, complex components, strong biological toxicity and difficulty degradation. The Fe0/H2O2 system can efficiently remove refractory contaminants from dye wastewater because of its great oxidation capability, rapid and efficient response and low cost. In this study, the Fe0/H2O2 process was utilized to treat simulated dye wastewater and the response surface method was employed to optimize process conditions. Reactive free radicals were detected by using electron paramagnetic resonance (EPR), and the degradation mechanism of dye wastewater was analyzed by comparing the changes in organic components before and after treatment using Fourier transform infrared spectroscopy (FT-IR) and ultraviolet visible light (UV-Vis). The changes of removal efficiencies of crystal violet, saffron T, TOC, COD and chroma in the dye wastewater were investigated. The degradation kinetics and degradation mechanisms of dye wastewater were explored. The results showed that the predicted removal efficiency of crystal violet using response surface method was 97.94%, which was only 0.36% (<2%) lower than the measured value, and the predicted removal efficiency of saffron T was 77.31%, which was only 1.3% (<2%) lower than the measured value, under the initial pH of 3, iron powder concentration of 0.3 g/L and H2O2 dosage of 20 ml/L. According to the kinetic study, the degradation processes of crystal violet, saffron T, COD and chroma were consistent with the BMG kinetic model. The correlation coefficient was higher than 0.98 and the initial degradation rate of crystal violet was the fastest. According to EPR analysis, ·OH was the main active substance for degradation of dye wastewater. According to FT-IR and UV-Vis spectroscopy, removal efficiencies of crystal violet and saffron T was the highest using the Fe0/H2O2 process, and the dye molecules were oxidized into small intermediates or small molecules. According to gas chromatography-mass spectrometry (GC-MS), the molecular structure of crystal violet and saffron T was destroyed by ·OH. The intermediate products were gradually degraded with the reaction, and finally decomposed into CO2 and H2O.

    Molecular mechanism study on chemical looping gasification of cellulose over iron oxide nanocluster
    Siwen ZHANG, Haiming GU, Shanhui ZHAO
    2025, 76(1):  363-373.  doi:10.11949/0438-1157.20240986
    Abstract ( 99 )   HTML ( 6)   PDF (6216KB) ( 243 )  
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    The chemical looping gasification (CLG) process of cellulose under the action of nano-iron oxide particles was studied by combining experiments with molecular simulation. Thermogravimetric experimental results show that iron oxide can accelerate the thermal decomposition of cellulose and reduce the peak temperature of thermal mass loss rate. The molecular dynamic modeling results show that cellulose begins to decompose and tar/volatile compounds are produced at 1500 K. Cellulose is almost completely decomposed, producing a large amount of fragmented molecules at 3000 K. The presence of iron oxide nanocluster promotes the shift of cellulose pyrolysis reactions towards lower temperatures and accelerates cellulose chain cleavage. Furthermore, tar and char conversion is enhanced through in situ oxygen supply. When the temperature reaches 3000 K, all cellulose is gasified with no remaining char. The gas yield and tar yield are 91.28%(mass) and 9.49%(mass) respectively. Individual product yields indicate that Fe2O3 nanocluster restricts the formation of tar compounds, while enhances the yield of CO and H2O. Radial distribution function (RDF) results of Fe2O3 nanocluster prove that iron atoms and oxygen atoms generally tend to separate from each other at high temperature. Lattice oxygen tends to move to the surface. Finally, the detailed reactions during CLG of cellulose were discussed at molecular level. A four-step mechanism was proposed for the CLG of cellulose by Fe2O3 nanocluster.

    Analysis of influence of operating temperature on water distribution, proton transport and performance of PEMFC
    Qiwo HAN, Yongfeng LIU, Pucheng PEI, Lu ZHANG, Shengzhuo YAO
    2025, 76(1):  374-384.  doi:10.11949/0438-1157.20240690
    Abstract ( 152 )   HTML ( 10)   PDF (6040KB) ( 41 )  
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    The operating temperature directly affects the water content and power density of the membrane, and determines the proton transport efficiency of the membrane. In order to study the effect of operating temperature on proton transport efficiency and performance of proton exchange membrane fuel cell (PEMFC), a membrane proton transport (MPT) model was proposed. The model takes into account the influence of the operating temperature on the film water content, deduces the output voltage calculation formula, and couples the MPT model into COMSOL for multi-physical field calculation. A fuel cell test system was built, and experiments and numerical simulations were carried out at inlet relative humidity of 100% and operating temperature of 50℃, 60℃ and 70℃. The output voltage was calculated based on MPT model, and the effects of operating temperature changes on transmembrane water flux, membrane water content and proton conductivity were analyzed. The results show that the maximum relative error between the MPT model and the experimental value is 8.41% when the operating temperature is 70℃. In the range of current density 0—800 mA/cm2, the relative error is 0.12%—2.52%. Under the same inlet pressure, inlet relative humidity and inlet flow, with the increase of operating temperature, the transmembrane water flux increases, the membrane water content decreases and the distribution becomes more uniform, the wetting degree of proton exchange membrane (PEM) is higher, and the proton conductivity increases.In the current density range of 0—650 mA/ cm2, the output voltage at 70℃ is lower than that at 50℃. On the contrary, it is higher than 50℃ and 60℃ in the current density range of 650—1300 mA/ cm2.With the increase of current density, the transmembrane water flux increases, the distribution of membrane water content becomes more uniform, and the proton conductivity increases under some conditions. When the operating temperature is 70℃, the power density of PEMFC is the highest, which is 399.73 mW/cm2.

    Reaction mechanism for the enhanced removal of selenite in water by ball-milling of zero-valent iron with Fe3O4
    Junyao QIAN, Chengze WANG, Jinhua ZHANG, Hua LIU, Zhaorui LIU, Jinxiang LI
    2025, 76(1):  385-393.  doi:10.11949/0438-1157.20240812
    Abstract ( 90 )   HTML ( 7)   PDF (4503KB) ( 361 )  
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    In order to enhance the performance of zero-valent iron (ZVI) in removing selenite [Se(Ⅳ)] from water, a modification method of magnetite (Fe3O4) ball-milled doped ZVI (BF-ZVI) was proposed. The results showed that the reaction rate of Se(Ⅳ) removal by BF-ZVI was 1.3—3.1 times that of the ball-milled ZVI without Fe3O4 (B-ZVI) in the range of initial pH 4.0—8.0. The key roles of free ferrous iron, structural ferrous iron and trivalent iron in the process of Se(Ⅳ) removal by BF-ZVI were clarified by the establishment of the correlation analysis between the iron reactive species in the BF-ZVI system and its Se(Ⅳ) removal. Based on the results of XPS and electrochemical impedance characterization, it was further illustrated that ball-milling synergistically with Fe3O4 can mediate the electron transfer of inner-core iron, thus enhancing the reduction and decontamination of Se(Ⅳ) by ZVI.

    Process safety
    Enhancing the flame stability in a flat plate burner using catalytic coating of CeO2-ZrO2
    Fan LI, Yanjun YIN, Junchao XU, Liqiao JIANG, Xiaohan WANG, Huaqiang CHU
    2025, 76(1):  394-404.  doi:10.11949/0438-1157.20240710
    Abstract ( 100 )   HTML ( 7)   PDF (5497KB) ( 378 )  
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    Regulating the interaction between flame and wall based on CeO2-ZrO2 coating material with excellent oxygen ion transport performance is a new strategy to achieve enhanced stable combustion. In this study, the effects of catalytically active CeO2-ZrO2 coating and ordinary stainless steel (STS304) wall surfaces on the performance of methane/air premixed flames with a stoichiometric ratio in parallel channels were studied by using planar laser induced fluorescence (OH-PLIF) technology. The characteristics of flame morphology changes, flame quenching properties, and the fluorescence signal distribution of OH radicals were obtained. The results showed that the thermal and chemical effects of CeO2-ZrO2 coating on flame height were related to wall temperature and channel spacing conditions. The quenching distance intervened by catalytically active coating decreased monotonically with wall temperatures increase. Compared with STS304 wall, under a high wall temperature condition, the highest OH fluorescence intensity in the flame core region showed an increasing trend, indicating a significant improvement in combustion intensity. For the condition with a channel spacing of 4 mm and a wall temperature of 700℃, the near-wall OH concentration on different wall surfaces was in the order of CeO2-ZrO2 coating > inert STS304 > reactive STS304, which was exactly opposite to the order of the temperature-compensated chemical action factors (the degree of radical deactivation at gas-solid interfaces), indicating that the modified wall surface with catalytically active CeO2-ZrO2 coating greatly reduced the quantity of radical annihilations innear-wall regions, showing promoting effects on stable combustion.

    Effect of vibration on the stability of on-site mixed emulsion explosive matrix with different water contents
    Feng LIU, Rujie BI, Quan WANG, Zhao KUANG, Xiangshuai MENG, Guoqiang HUANG
    2025, 76(1):  405-415.  doi:10.11949/0438-1157.20240702
    Abstract ( 88 )   HTML ( 5)   PDF (3333KB) ( 357 )  
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    In order to study the effect of vibration on the stability of emulsion explosives matrix with different water contents in field mixing, the microstructure, ammonium nitrate precipitation, internal phase particle size and viscosity changes of matrix specimens before and after the vibration were tested by using a speed-regulated oscillator to simulate the vibration and bumpy conditions that the specimens might undergo during the transportation process. According to the experimental results, the emulsion explosive matrix's internal phase particle size drops from 6.431 μm to 4.904 μm when the water content rises from 16% to 20%. Consequently, the matrix's anti-vibration performance first improves before weakening. After four vibration cycles, the sample with a 20% water content exhibited significant crystallization and demulsification. Following eight cycles, there was the greatest vibration resistance, a 9.72-fold increase in crystallization quantity, and a 161% rise in viscosity. After four cycles, the sample with 18% water content still has a largely intact W/O structure. Following eight cycles, there is the maximum vibration resistance, a 6.71-fold increase in crystallization, and a 144% rise in viscosity. An excessively wet matrix is more prone to demulsification, vibration, and crystallization. When the water content is 18%, the viscosity of the on-site mixed emulsion explosive prepared by this formula meets the pumping requirements, the crystallization amount and viscosity change rate under the influence of vibration are the smallest, the anti-vibration ability is the best, and the stability is the best.