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Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select 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 （15）      PDF （3911KB）（15）       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 Select 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 （12）      PDF （5086KB）（14）       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 Select Migration behaviors and deformation characteristics of discrete bubbles in a variable diameter circular tube Feng LI Liang MING Lei XING Minghu JIANG Lixin ZHAO Shuai GUAN The Chinese Journal of Process Engineering    2025, 25 (4): 341-353.   DOI: 10.12034/j.issn.1009-606X.224229 Abstract （16）      PDF （9843KB）（41）       Knowledge map    Save The morphological evolution and migration dynamics of discrete bubbles in variable diameter pipelines have not been clearly analyzed. The deformation dynamics behavior of discrete bubbles in a variable diameter circular tube is an important theory to guide the transport and separation of gas-liquid two-phase mixture. Therefore, high-speed camera technology, combined with numerical simulation, is used to explore the migration and fragmentation mechanism of discrete bubbles in variable diameter pipes. For the structure of a variable diameter circular pipe, a study on the migration behaviors of discrete bubbles in the variable diameter field is conducted under different Reynolds numbers and bubble sizes. The flow pattern, velocity field and bubble deformation characteristics within the variable diameter circular pipe at various inlet Reynolds numbers are analyzed. The aim is to explore the interaction patterns between the flow field characteristics and discrete bubbles and provide theoretical support for revealing the motion and deformation mechanism of discrete bubbles in variable cross-section field. The results indicate that the surrounding fluid velocity is altered by bubbles. The velocity gradients are increased, and the turbulence kinetic energy in the surrounding flow field is elevated. At the same time, the dramatic change of turbulent kinetic energy in the sudden expansion section leads to the rapid deformation or even fragmentation of discrete bubbles in the variable diameter circular tube field. Additionally, as the inlet Reynolds number increases, the fragmentation position of bubbles in the flow field tends to approach the sudden expansion section. When Re=5.16×103, the shortest bubble fragmentation distance is 16.09 mm. When the Reynolds number is constant, as the bubble radius increases from 2.5 mm to 4.5 mm, the dimensionless maximum deformation of the bubble is increased from 0.26 to 0.67. The numerical simulation results demonstrate good agreement with experimental findings. Related Articles | Metrics Select Simulation of flow and mixing characteristics of binary particles in gas-solid fluidized bed (I): axial/radial flow field distribution characteristics Guifang WANG Shuangzhu KONG Jian LI Xiuying YAO Yiping FAN Chunxi LU The Chinese Journal of Process Engineering    2025, 25 (4): 354-363.   DOI: 10.12034/j.issn.1009-606X.224286 Abstract （19）      PDF （4002KB）（28）       Knowledge map    Save In the fields of petrochemical and chemical engineering, some new processes involving the reactions of gas and catalysts with distinct functions and physical properties have been proposed. Since considerable physical properties difference in density, size and shape between two types of particles,the hydrodynamic behaviors of the binary mixture in the gas-solid fluidized bed are undoubtedly complex. This work presents a numerical investigation on the mixing and flow characteristics of binary particles (Geldart A particles and Geldart D particles) and gas in the bottom region of the gas-solid fluidized bed-riser coupling reactor. Considering the non-uniform structures in intermediate scale, the Eulerian-Eulerian multi-fluid model as well as the drag force model based on the energy minimization multi-scale (EMMS) are used. The axial distributions of bed density and pressure in the binary particle fluidized bed are investigated. By analyzing the turning points of these two parameters, the location of interface between the dense phase zone and the dilute phase zone is determined. The cross-sectional average solid holdup of Geldart A particles and Geldart D particles in the axial direction is also discussed. By comparing the parameter, the relative cross-sectional average solid holdup rates of the two types of catalysts, it is found that most Geldart D particles accumulate at the bottom of the bed in the axial direction. Furthermore, when the binary particle system is composed of coarse particles with low density and fine particles with high density, the distribution of the bed density in the bottom region of the bed layer is steady. In the radial direction, by analyzing the radial distributions of the local solid holdups of the two-solid phase, it is seen that both the Geldart A particles and the Geldart D particles tend to travel towards wall area. By introducing the new parameter, the local relative solid holdup, it is revealed that the Geldart D particle has a stronger tendency towards the wall compared to Geldart A particles. Related Articles | Metrics Select Simulation of flow and mixing characteristics of binary particles in gas-solid fluidized bed (II): mechanical analysis of radial distribution characteristics of flow field Guifang WANG Shuangzhu KONG Jian LI Xiuying YAO Yiping FAN Chunxi LU The Chinese Journal of Process Engineering    2025, 25 (4): 364-372.   DOI: 10.12034/j.issn.1009-606X.224287 Abstract （14）      PDF （2980KB）（13）       Knowledge map    Save Due to the distinct differences in size, density or shape of the particles' physical properties, the pattern of the two solid phases is complex. The hydrodynamics of binary mixtures of Geldart A particles and Geldart D particles in gas-solid fluidized bed, particularly the radial flow behaviors, are investigated. By comparing relative solid holdup, it is found that Geldart D particles tend to accumulate near the wall. However, few studies have discussed the occurrence for this phenomenon. The Kutta-Joukowski transverse force is introduced to analyze the distribution characteristics of local density and the local fractions of binary particles in the radial direction from the viewpoint of the forces on particles. Considering the fact that non-uniform structures in intermediate scale, the Eulerian-Eulerian multi-fluid model as well as the drag force model based on the energy minimization multi-scale (EMMS) is used. The Kutta-Joukowski transverse force on particles presents a non-uniform distribution in the radial direction. It is related to the gas-solid velocity-difference vector and the particle velocity radial gradient. Based on the radial profile of the Kutta-Joukowski transverse force, the flow regime is divided into three zones, the Kutta-Joukowski uniform influence zone (zone I), the velocity gradient dominant zone (zone II), and the velocity-difference vector dominant zone (zone III). The results show that the Geldart A particles and Geldart D particles exhibit similar tendencies in zone I to move towards the wall, resulting in a uniform distribution. In zone II and III, both Geldart A particles and Geldart D particles are exerted by the Kutta-Joukowski transverse force towards the wall, leading to a core-annulus phenomenon with low concentration at the center and high concentration near the wall. Compared to Geldart A particles, relatively higher Kutta-Joukowski transverse force on Geldart D particles results in a stronger tendency to move towards the wall region in zone II. In zone III, on the other hand, the tendencies for Geldart A particles and Geldart D particles travelling towards the wall are relatively weak. Related Articles | Metrics Select 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 （10）      PDF （2378KB）（3）       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 Select Experimental study on new type of wire plate electrostatic precipitator under synergistic effect of wet chord grid Houcheng DING Yaqin XUE Quanlong DENG Wenjing ZHANG Zhenyang CHEN The Chinese Journal of Process Engineering    2025, 25 (4): 382-388.   DOI: 10.12034/j.issn.1009-606X.224304 Abstract （8）      PDF （3889KB）（6）       Knowledge map    Save In order to improve the dust removal efficiency of fine particulate matter in industry, based on the traditional wet string grid filtration dust removal and electrostatic precipitator theory, a new electrostatic precipitator experimental system was built by dividing wet dust removal and electrostatic precipitator into zones, under the synergistic effect of wet string grid. The influence of wavelength and amplitude of corrugated plates on dust removal efficiency under different voltages and wind speeds was explored through a single electrostatic precipitator experiment, and the optimal wavelength and amplitude values of corrugated plates were obtained. The influence of voltage, wind speed, and atomization pressure on the dust removal efficiency was explored through composite wet electrostatic precipitator experiments, and verified the dust removal effect of corrugated plates as dust collection plates in wet electrostatic precipitator systems. The results indicated that the dust removal efficiency in a single electrostatic precipitator was directly proportional to the voltage and inversely proportional to the wind speed. The dust removal efficiency of corrugated plates with different wavelengths and amplitudes was significantly improved compared to flat plates under different voltage and wind speed conditions, the impact of amplitude on the dust removal efficiency of corrugated plates was more significant, the corrugated plate with a wavelength of 150 mm and an amplitude of 60 mm had the best dust removal efficiency. The dust removal effect of the composite wet electrostatic precipitator system was significantly improved compared to a single electrostatic precipitator system, the dust removal efficiency of the combination of corrugated plate and water in the composite wet electrostatic precipitator system was higher than that of the combination of flat plate and water. The dust removal efficiency increased first and then decreased with the increase of wind speed and atomization pressure, which was proportional to the voltage. When the voltage, wind speed, and atomization pressure are 30 kV, 0.6 m/s, and 6 MPa, respectively, the maximum dust removal efficiency of the system reached 96.08%. Related Articles | Metrics Select 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 （21）      PDF （4849KB）（17）       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 Select Leaching behavior of valuable metals from paleo-terrestrial sedimentary rare earth ore leaching residue in sulfuric acid solution Xingyu MAO Xianquan AO Yang CAO Yu GUO The Chinese Journal of Process Engineering    2025, 25 (4): 399-407.   DOI: 10.12034/j.issn.1009-606X.224199 Abstract （7）      PDF （6313KB）（5）       Knowledge map    Save Paleo-terrestrial sedimentary rare earth ore is a new type of rare earth ore, the process produces a large amount of rare earth residue after acid leaching separation of rare earth elements. Al, Fe, and Ti present in the rare earth residue are important metals, and the separation and extraction of metal elements from the rare earth residue can improve the utilization value of rare earth ores and solve the solid waste disposal problems. Sulfuric acid solution was used to leach the residue from rare earth ore processing to investigate the effect and reaction mechanism of sulfuric acid solution on the leaching behavior of Al, Fe, and Ti. The results showed that the sulfuric acid solution could effectively dissolve silica-aluminate and hematite in the rare earth ores, selectively leach Al and Fe. In contrast, anatase did not easily react with the sulfuric acid solution, and the leaching rate of Ti was low, which stayed in the leaching residue together with Si. The optimal reaction conditions were optimized using one-way and orthogonal experiments, and the leaching rates of Al, Fe and Ti reached 86.44%, 94.00%, and 7.14%, respectively, under the optimal reaction conditions of reaction temperature of 115℃, reaction time of 6 h, acid residue mass ratio of 2.1 g/g and liquid-solid ratio of 4 g/g. It was found that the reaction temperature significantly affected the leaching rates of Al and Fe. Then (NH4)2SO4 was added to the leaching solution, and Al could be converted to NH4Al(SO4)2 crystals and precipitated, and Al2O3 was produced by roasting to realize the separation of Al and Fe. This study realized the selective recovery of Al and Fe elements in rare earth residue, and enriched Si and Ti elements in the leaching residue, which was conducive to the recovery of Ti elements in the next step. Related Articles | Metrics Select Phase equilibria and thermodynamics of the sodium benzenesulfonate-Na2SO4-H2O ternary system Jiahui YI Benren LIAO Peng CHEN Jingyu WEI Han YAO Huiting HUANG Zhihao LU Lehua ZHANG The Chinese Journal of Process Engineering    2025, 25 (4): 408-415.   DOI: 10.12034/j.issn.1009-606X.224274 Abstract （6）      PDF （2508KB）（7）       Knowledge map    Save Industrial organo-sulfonic acid wastewater contains high concentrations of inorganic salts and various organo-sulfonates, causing significant challenges for their efficient removal, separation, and recovery. These waste streams often arise from complex industrial processes, and their intricate compositions make effective treatment and recycling more difficult. Herein, the phase equilibrium data for the sodium benzenesulfonate (BSNa)-sodium sulfate (Na2SO4)-water (H2O) ternary system were measured at temperatures of 273.15, 283.15, and 313.15 K using both the isothermal dissolution equilibrium method and Schreinemakers' wet residue method. Thermodynamic analysis of the dissolution process was performed using the van't Hoff equation, offering valuable insights into the system's behavior under different temperature conditions. At 313.15 K, the phase diagram indicated one invariant point, two univariant curves, and three distinct crystallization regions, corresponding to Na2SO4, BSNa, and their co-crystal mixture. However, at the lower temperatures of 273.15 and 283.15 K, the system displayed only one invariant point, one univariant curve, and two crystallization regions, specifically for Na2SO4?10H2O and a co-crystal region consisting of Na2SO4?10H2O and BSNa. Notably, no distinct crystallization region or solubility curve for BSNa was observed at these lower temperature ranges. Additionally, freeze crystallization experiments demonstrated no evidence of double salts or eutectic mixtures forming within the ternary system. This suggested that separating the components at lower temperatures, particularly around 283.15 K, was not only more efficient but also more cost-effective for obtaining pure salts. The thermodynamic analysis further revealed that the dissolution of Na2SO4 in this system was an endothermic, non-spontaneous process with an increase in entropy. The changes in enthalpy significantly influence the Gibbs free energy of dissolution, impacting the separation process. This research provided insight into the effective separation and recovery of BSNa and Na2SO4 from industrial wastewater, offering a solid foundation and practical guidance for improving wastewater treatment processes in industrial applications. Related Articles | Metrics Select 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 （10）      PDF （3364KB）（8）       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 Select Heat transfer characteristics of micro-encapsulated phase change material slurry in metal foam filled microchannels Yongtong LI Jing SUN Weibo WANG Boyu YANG Yunxi YANG The Chinese Journal of Process Engineering    2025, 25 (3): 233-240.   DOI: 10.12034/j.issn.1009-606X.224227 Abstract （88）   HTML （9）    PDF （4566KB）（44）       Knowledge map    Save Micro-encapsulated phase change material slurry (MEPCMs) is a novel kind of functional thermal fluid, which has great potential in the field of electronic thermal management, thermal storage, etc. To improve the thermal management performance of high-power density electronic devices, a dual-enhanced heat transfer method with the combination of MEPCMs and metal foam was employed to improve the cooling performance of mini-channel heat sink in the present study. Numerical methods were utilized to investigate the heat transfer capability, flow resistance, and overall performance evaluation criteria (PEC) by considering the effects of MEPCMs mass fractions (5wt%, 10wt%, and 20wt%), inlet velocities, and metal foam filling ratios. The results indicated that the maximum temperature of metal foam mini-channel decreased and pressure drop increased with increasing the mass fraction of MEPCMs. At an inlet velocity of 0.06 m/s, increasing the mass fraction from 5wt% to 20wt%, the pressure drop increased by 2.09 times. 5wt% MEPCMs presented the best comprehensive heat transfer performance, and the PEC value was improved by 8.15%~12.18% compared with pure water. The filling ratio of the metal foam also significantly affected the heat transfer performance of the microchannel, and the cooling performance was best when the mini-channel was fully filled with metal foam. For the entire range of flow velocities, using 5wt% MEPCMs as the coolant, average Nuave of mini-channel heat sink fully filled with metal foam was 9.06 times of the empty mini-channel heat sink, and the pressure drop came to 56.91 times. With the comprehensive consideration of heat transfer enhancement and flow resistance, the PEC value could reach up to 2.61. The present findings could provide theoretical guidelines for developing more coefficient and compact liquid-cooled electronic devices. Related Articles | Metrics Select Effect of solid phase volume fraction on cavitation characteristics of O-type ball valve Zhaonian ZHOU Binbin WU Tingfeng HUA Zhaotong WANG Zhijiang JIN Wenqing LI Jinyuan QIAN The Chinese Journal of Process Engineering    2025, 25 (3): 241-248.   DOI: 10.12034/j.issn.1009-606X.224257 Abstract （57）   HTML （9）    PDF （2994KB）（12）       Knowledge map    Save The O-type ball valve serves as an important fluid control equipment in the coal chemical industry. However, during the operation process, cavitation phenomenon is very easy to occur inside the ball valve which will greatly affect production safety. The working medium of the ball valve is a fluid containing solid particles, and the volume fraction of particles will affect the cavitation, but the mechanism of how the fraction of particles affect cavitation is not clear. In order to solve this problem, numerical simulation is used to investigate the effect of solid phase volume fraction on cavitation in ball valve under different ball angles. The degree of cavitation in the ball valve can be illuminated by the pressure, cavitation number, and gas phase volume fraction on the valve ball outlet section. The results show that when the ball angle is 30° and 45°, there is no cavitation in the valve under any solid phase volume fraction. However, when the ball angle is 60°, different solid phase volume fractions have different effects on cavitation. When the solid phase volume fraction increases from 0% to 10%, the cavitation degree in the ball valve is gradually weakened. When the solid phase volume fraction increased from 10% to 20%, cavitation in the valve gradually increased. In addition, it is interesting that when the valve ball angle reaches 75°, cavitation in the ball valve will be promoted by any solid phase volume fraction. A lot of work has been done in this work to reveal the influence mechanism of solid phase volume fraction and ball valve angles on cavitation characteristics of O-type ball valves, and some useful results have been obtained, which has a certain guiding on controlling the working environment and multi-phase flow simulation of O-type ball valves. Related Articles | Metrics Select Numerical simulation study of pulse soot removal characteristics of pleated cartridge based on fluid-solid coupling Yifei LI Fuping QIAN Wenyuan HU Qi MA Jinli LU The Chinese Journal of Process Engineering    2025, 25 (3): 249-260.   DOI: 10.12034/j.issn.1009-606X.224243 Abstract （70）   HTML （8）    PDF （9171KB）（21）       Knowledge map    Save Pulse jet airflow is the main means of cleaning dust in the filter cartridge dust collector. The action of the air jet causes the cartridge filter element to expand and shake, and the dust on the cartridge is peeled off and falls into the ash hopper, thus maintaining the clean and efficient filtration performance of the cartridge. In order to more accurately reflect the impact of the blowing airflow on the filter cartridge, the static structural module (Static Structural) in ANSYS Workbench is employed to perform the fluid-solid coupling of the cartridge pulse soot removal, and the resulting pressure is applied to the cartridge. This allows for the conclusions related to the solid mechanics of the filter cartridge under the pressure of pulse blowing to be drawn. By comparing the simulation results with the same blowing time and different blowing distances, the impact of the blowing airflow on the pleated structure of the cartridge can be determined. Firstly, Fluent simulation is employed to obtain the pressure change within the cartridge. It is observed that although the pressure exhibits slight numerical discrepancies under varying blowing distances, its distribution trend remains consistent: the airflow descends along the length of the filter element and subsequently spreads along the radial direction, the static pressure within the cartridge accumulates from the bottom in an upward trajectory. The lower portion of the cartridge exhibits a relatively elevated static pressure, while the upper section displays a comparatively reduced pressure. The accumulation of pressure within the cartridge is discernible. The static structure module in ANSYS Workbench is employed to couple the pressure derived from the Fluent simulation conducted in the preceding step to the pleated structure of the filter cartridge. This enables the acquisition of the total deformation, elastic strain, and maximum shear stress values of the pleated structure of the filter cartridge and their distribution law through simulation under the same time set. In the experimental range, when the blowing distance is 150 mm, the best values of each parameter of the airflow acting on the pleated structure of the cartridge are obtained: the total deformation is 0.133 27 μm, the elastic strain is 3.018×10-4 μm, and the maximum shear stress is 222.69 Pa. Related Articles | Metrics Select CFD simulation of bubble columns with tube bundles: impact of turbulence models Nan ZHANG Xiaoping GUAN Kangjun WANG Ning YANG The Chinese Journal of Process Engineering    2025, 25 (3): 261-272.   DOI: 10.12034/j.issn.1009-606X.224206 Abstract （71）   HTML （8）    PDF （6598KB）（19）       Knowledge map    Save The accuracy of CFD simulation results for bubble columns depends on closure models, such as interphase force models and turbulence models. Most of the previous reports were for empty column without internals, and currently, there is a lack of studies related to bubble column with internals. This study examined the effects of six commonly used turbulence models (Standard k-ε, RNG k-ε, Realizable k-ε, Standard k-ω, SST k-ω, and RSM) on the hydrodynamics in the pilot-scale bubble columns without internals and with tube bundles. The results showed that the RSM predicted significantly higher for turbulent kinetic energy, turbulent dissipation rate, and turbulent viscosity in the empty column compared to eddy viscosity models (k-ε and k-ω models). However, this difference was considerably reduced in the bubble column with tube bundles, and the tube bundles significantly suppressed the turbulence intensity in the liquid phase. Meanwhile, by comparing the simulated gas holdup and axial liquid velocity values with experimental data, it was found that the eddy viscosity models accurately predicted the gas holdup in the central region of the empty column, while the RSM accurately predicted the gas holdup in all regions except the central region. However, the radial distribution of gas holdup predicted by six turbulence models in the bubble column with tube bundles was almost identical, with accurately predicting the gas holdup only in the 0.5<r/R<0.7 region. The Realizable k-ε model's predictions of axial liquid velocity in both empty column and the bubble columns with tube bundles were in good agreement with experimental data, significantly outperforming other turbulence models. Therefore, it was recommended to use the Realizable k-ε model for future simulations of hydrodynamics in bubble columns. Related Articles | Metrics Select Investigation of enhanced boiling heat transfer characteristics of hierarchical gradient porous copper surface Er SHI Shuangrui YE Youlan WANG Qi PENG Bin ZHAO Changwei JIANG The Chinese Journal of Process Engineering    2025, 25 (3): 273-282.   DOI: 10.12034/j.issn.1009-606X.224233 Abstract （67）   HTML （7）    PDF （4605KB）（10）       Knowledge map    Save To enhance boiling heat transfer for promoting the efficiency of the energy system, the porous surfaces with structural gradients were developed on pure copper substrates by employing the electrochemical deposition method. In this study, honeycomb-like porous structures and hierarchical axial honeycomb gradient porous structures were fabricated using constant current single-step deposition and constant current constant voltage two-step deposition methods, respectively. Saturated pool boiling heat transfer experiments were conducted using HFE-7100 as the working fluid to investigate the influence of the gradient pore size changes on the boiling heat transfer performance of porous surfaces. The results demonstrated that the hierarchical gradient porous surface, which had a total deposition time of 60 seconds and an increased second-step deposition voltage of 3 V, showed the most significant heat transfer enhancement. The wall superheat at the boiling initiation point was 9.5 K, a 43.00% decrease compared to the smooth surface at 16.8 K. Moreover, the critical heat flux and heat transfer coefficient reached 522.02 kW/m2 and 22.76 kW/(m2?K), respectively, exhibiting with enhancements of 193.40% and 261.01% compared to the smooth surface. The hierarchical porous surface had two types of nucleation sites: internal pores and dendritic protrusions. The micropores and the internal micropores of the dendrites exhibited a wide range of pore sizes. This extensive distribution of pore sizes not only increased the density of nucleation sites and effective heat transfer area but also reduced the nucleation energy barrier. The axial pore size gradient accelerated bubble evolution, and the capillary suction force provided by the gradient porous structure and dendrites facilitated the return flow of the working fluid to the nucleation sites both horizontally and vertically, thereby enhancing the boiling heat transfer coefficient and critical heat flux of the hierarchical gradient porous surface. Related Articles | Metrics Select Numerical study on influence of pulse amplitude on patterns of gas-liquid-liquid three-phase flow in pulsed extraction column with discs and doughnuts Ting YU Xiucheng YU Zonghui LU Zhe XIAO Ming QU Hui HE Guoan YE The Chinese Journal of Process Engineering    2025, 25 (3): 283-292.   DOI: 10.12034/j.issn.1009-606X.224194 Abstract （60）   HTML （8）    PDF （4541KB）（16）       Knowledge map    Save The pulsed extraction columns with discs and doughnuts play a critical role in the field of spent fuel reprocessing. The countercurrent contact between liquid-liquid two-phase fluids in the column is facilitated through periodic pulses, which significantly influences the separation and purification processes of chemical elements. Although a considerable amount of research on pulse extraction columns with discs and doughnuts has been conducted through simulation, few studies have utilized the actual industrial structure of these columns as examples. A gas-liquid-liquid three-phase flow model coupled with PBM (Polulation Balance Model) to evaluate discrete phase droplet diameter distribution, reflecting the actual structure of pulsed extraction column with discs and doughnuts, was established using CFD (Computational Fluid Dynamics) simulation technology. And it verified the accuracy of the modeling through multiple calculation cases, aiming to investigate the influence of pulse amplitude on the evolution of flow field inside a pulsed extraction column. The model's accuracy was demonstrated through comparison with public literature, and the impact of pulse amplitude on the micro-flow behavior inside the pulsed extraction column was calculated, analyzed and verified. Under the working condition with a pulse amplitude of 1.2 cm, the amplitude had a relatively small impact on the motion of water and oil phases, and the water phase accumulated on the baffle. Under the working conditions of pulse amplitudes of 7.2 and 14.4 cm, the amplitude had a significant impact on the direction and velocity of the water and oil phases, with the water phase separating from the baffle and dispersing into smaller droplets. Furthermore, it was found that as the pulse amplitude increased, both the turbulence kinetic energy and turbulence energy dissipation rate also increased, reaching a maximum value in the region where the fluid impacted the solid wall. Finally, from the distribution of droplet diameter fraction, it was evident that as the pulse amplitude increased, the proportion of small diameter aqueous droplets was higher, which enhanced the extraction. This study used the Euler-Euler two-phase flow model coupled with the PBM to accurately simulate the gas-liquid-liquid three-phase evolution phenomenon in pulse extraction columns, providing a reference for the design and process optimization of subsequent pulsed baffle extraction columns, which laid the foundation for introducing the mass transfer model and heat transfer model through CFD method to analyze the chemical process inside the column in further study. Related Articles | Metrics Select Optimization of phosphorus release from anaerobic fermentation of cow manure and phosphorus recovery through vivianite crystallization Zhihao CHEN Weihua LI Tingting YANG Yixin LIU The Chinese Journal of Process Engineering    2025, 25 (3): 293-301.   DOI: 10.12034/j.issn.1009-606X.224223 Abstract （59）   HTML （8）    PDF （2793KB）（7）       Knowledge map    Save With the rapid development of the livestock and poultry farming industry in China, the disposal and resource utilization of livestock and poultry waste have attracted widespread attention. To maximize the recovery of phosphorus from this waste, this study focuses on fresh cow manure, which is rich in phosphorus, and proposes a novel pathway for phosphorus recovery. By examining the effects of different manure concentrations, anaerobic fermentation durations, and initial pH values on phosphorus release during the anaerobic fermentation of fresh cow manure, the study found that optimal conditions for phosphorus release were achieved with a manure concentration of 180 g/L, an anaerobic fermentation period of 14 days, and the initial pH of 7, resulting in a phosphorus release of 156.57 mg/L. To recover phosphorus from the supernatant of anaerobically fermented cow manure, Fe2+ salts were added to induce the vivianite crystallization. L9(34) orthogonal experiments were conducted to investigate the effects of reaction temperature, pH, and Fe/P ratio on the phosphorus recovery rate. The results showed that the factors affecting phosphorus recovery efficiency in order of significance, were the initial pH value, reaction temperature, and Fe/P ratio. The optimal for the process were found to be a reaction temperature of 35℃, a pH of 7, and a Fe/P ratio of 1.9. Under these conditions, the highest phosphorus recovery rate of 84.20% was achieved, and the purity of vivianite was 25%. The recovered products were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. An improved sequential phosphorus extraction method was employed to determine the abundance of vivianite in the recovered products. The research provides a valuable reference for the synthesis of high-value vivianite, based on the effective extraction of phosphorus from fresh cow manure. Related Articles | Metrics Select Influence of alumina on reactivity of biopitch anode for aluminum electrolysis Kunmo ZHANG Wei WANG The Chinese Journal of Process Engineering    2025, 25 (3): 302-310.   DOI: 10.12034/j.issn.1009-606X.224254 Abstract （70）   HTML （7）    PDF （1533KB）（29）       Knowledge map    Save The carbon anode is prepared by baking a mixture of petroleum coke aggregate and pitch at 180℃ for use in the aluminum industry. Due to its good wettability and environmental friendliness towards carbon anode aggregates, the biopitch is considered as a promising carbon anode binder. The biomass conversion technology, substituting traditional coal tar pitch with biopitch, partially or completely in the aluminum production, has recently received domestic and foreign researchers' attention. However, the biopitch typically has a lower coking value which may have a negative impact on its performance. In this work, alumina additives have been added to the biopitch anode to improve its performance. In order to understand the effect of alumina additives on the performance of biopitch anodes, biopitch anode materials were prepared by hot pressing and sintering in the laboratory with alumina as a catalyst. The CO2 reactivity of the anodes was tested with a thermogravimetric analyzer in laboratory. The influence of additives on the performance of the anodes and the CO2 reactivity as well as the wettability of biopitch on petroleum coke were studied by X-ray diffraction analysis, optical microscopy (OM) and high-resolution transmission electron microscopy (HRTEM). The results indicated that the biopitch exhibited better wettability than coal tar pitch with the same surface tension and viscosity. In addition, a transformation occurred from initially less well-ordered to ordered structure for the biopitch anode with alumina additives during baking, thereby increasing the coking value of the biopitch, reducing the CO2 reactivity of biopitch anodes and improving their antioxidant properties. Accompanied by an enhancement in the graphitization degree and an increase of carbon structural orders, the performance of biopitch anodes has been improved significantly with alumina as additives. The biopitch could be used to replace 100% of the coal tar pitch in a carbon anode recipe. This study has provided a theoretical guidance for the application of biopitch anodes and the reduction of energy consumption in aluminum electrolysis. Related Articles | Metrics Select Preparation, characterization and release properties in vitro of altrenogest nanosuspension drug delivery system Chao LI Dongbo LI Yueli WANG Haiyan ZHAO Junhao ZHANG Hualin FU The Chinese Journal of Process Engineering    2025, 25 (3): 311-322.   DOI: 10.12034/j.issn.1009-606X.224240 Abstract （56）   HTML （7）    PDF （2082KB）（9）       Knowledge map    Save Altrenogest (ALT) is oral progestin with poor solubility (~10 μg/mL) and rapid metabolism in vivo, which severely constraints on clinical effectiveness. Nanosuspension drug delivery systems (NS) can reduce the drug particles to nanometer size and improve the solubility and bioactivity of insoluble drugs. The factors and mechanism of altrenogest nanosuspension (ALT-NS) formation were analyzed and investigated using the anti-solvent precipitation method and its quality was evaluated. The preparation process and prescription composition were analyzed and optimized using single factor experiments and the central composite design-response surface methodology (CCD-RSM), and the experiments of characterization, chemical structure analysis, crystalline shape examination, physical stability and release experiments in vitro were applied to evaluate the quality of ALT-NS. The optimal prescription and process were determined as follows: altrenogest 0.4wt%, sodium dodecyl sulfate (SDS) 25 mg/mL, hypromellose (HPMC) 4 mg/mL, stirring speed of 1000 r/min, and stirring time of 10 minutes. The formulation was a light yellow clarified liquid, and the drug particles were in the form of spherical particles with an average particle size of 104.87±1.10 nm, PDI (particle size distribution index) of 0.19±0.01, and Zeta potential of -37.87±0.81 mV, the drug was transformed from crystalline to amorphous state, and the use of freeze-drying technology to make ALT-NS into freeze-dried powder could further improve its physical stability. The cumulative release of the preparation group in vitro was 98.4% at 72 h,which was about 1.54 times higher than that of the original group, showing high efficiency and smooth drug release. In conclusion, the optimization of the prescription composition and preparation process of ALT-NS using the anti-solvent precipitation method can significantly reduce the physical size and specific surface area of ALT, improve the dissolution and release efficiency of ALT, and the formulation has the efficient and fast drug release characteristics, which is expected to provide a reference for the clinical application of ALT-NS. Related Articles | Metrics Select Data driven modeling of energy consumption and product quality in ethylene glycol distillation process Kangkang FENG Xin GENG Qinghui LOU Yu WANG Huajun HU Xiangjian SHI Cuimei BO The Chinese Journal of Process Engineering    2025, 25 (2): 142-149.   DOI: 10.12034/j.issn.1009-606X.224158 Abstract （66）   HTML （1）    PDF （2303KB）（32）       Knowledge map    Save With the rapid development of polyester industry, the increasing demand of ethylene glycol (EG) is in conflict with the shortage of supply in China. Large project of EG production from coal has been receiving more and more attention. In the production of coal-to-ethylene glycol, the optimization of distillation operations represents a vital means to achieve energy saving and consumption reduction, as well as quality enhancement and efficiency improvement. The foundation of optimization lies in the establishment of precise models for the process. However, due to the complex reactions, strong system coupling, and non-linearity inherent in the distillation process, it is difficult to accurately construct models using traditional mechanistic methods. Therefore, this study uses the distillation process of coal-to-ethylene glycol as the research subject, employing a refined least squares support vector machine (LSSVM) algorithm to accurately construct energy consumption and product quality models for the ethylene glycol distillation process. In this process, the actual industrial data from the coal-to-ethylene glycol distillation process was used as the benchmark, the mutual information method was employed to extract the main feature parameters, and variable screening and data pre-processing were conducted. Subsequently, by introducing local target sets and using the UMDA algorithm for iterative optimization, the optimal hyperparameters were derived. After determining the optimal hyperparameters, the improved LSSVM algorithm was used to model the data samples and further compared this model with other purity and energy consumption models established by different algorithms. This comparison confirmed the high efficiency and accuracy of the improved LSSVM algorithm based on UMDA proposed in this work. In summary, compared with traditional support vector machine methods, the LOS-LSSVM model based on the UMDA optimisation process has a clear advantage in data fitting, accurately reflecting the actual situation of the distillation process and effectively improving the operational efficiency of ethylene glycol production. Related Articles | Metrics Select Research on influence of oxygen lance area position on flow characteristics of large copper smelting oxygen bottom blowing furnace Baocheng JIANG Tao XIAO Songsong WANG Xueyi GUO Qinmeng WANG The Chinese Journal of Process Engineering    2025, 25 (2): 150-158.   DOI: 10.12034/j.issn.1009-606X.224173 Abstract （68）   HTML （1）    PDF （4194KB）（40）       Knowledge map    Save With the increasing demand for clean smelting of complex copper containing resources in China, oxygen bottom blowing copper smelting technology is playing an important role, and higher requirements are being put forward for its core equipment's (bottom blowing furnace) smelting capacity. Compared with other bottom blown furnaces, large oxygen bottom blown furnaces have larger specifications and more complex structures, and a high degree of matching between structure and function will be a very important issue. The position of the oxygen lance area is an important factor affecting the fluid flow and mass transfer inside a large oxygen bottom blowing furnace, thereby having a significant impact on the smelting effect. This work takes a large-scale copper smelting oxygen bottom blowing furnace of a certain enterprise as the research prototype, and uses numerical simulation methods to study the influence of the position of the oxygen lance on the flow characteristics of the large-scale oxygen bottom blowing furnace. The main focus is to investigate the influence of the position of the oxygen lance on the functional area and flow field inside the furnace. The results indicate that adjusting the position of the oxygen lance area can alter the distribution pattern of the functional areas inside the furnace. The "one end reaction and one end settlement" mode results in an asymmetric distribution of functional areas within the furnace. The effective extension of the settlement zone is conducive to the full separation of slag and matte. Offsetting the oxygen gun area towards the copper discharge port by 2300 mm form a "reaction at one end and settling at the other" mode. The settling area in front of the slag port is extended by 53.74%, and copper matte and copper slag achieve a more comprehensive and reasonable transition, full separation, and can be used as a directional control measure to optimize production. Related Articles | Metrics Select Reaction and gas-solid flow characteristics of calcium carbide synthesis in a fluidized bed Xu WANG Guohui SU Ting LI Zhennan HAN Liangliang FU Guangwen XU The Chinese Journal of Process Engineering    2025, 25 (2): 159-168.   DOI: 10.12034/j.issn.1009-606X.224166 Abstract （62）   HTML （2）    PDF （8788KB）（30）       Knowledge map    Save Calcium carbide (CaC2) synthesis is a typical high-temperature solid-phase reaction. By reducing the particle sizes of raw material, the intra- and interparticle heat and mass transfer can be significantly improved, thus realizing calcium carbide synthesis at relatively low temperatures and then driving technological revolution. Based on this, a fluidized bed CaC2 synthesis process was proposed in this study, and the reaction characteristics and hydrodynamics of CaC2 synthesis from small-particle raw materials were investigated in a fixed bed and spouted fluidized bed, respectively. Besides, the reactions on the particle surface and its morphological changes during the reaction were analyzed, and the defluidization mechanism was further explored. The results showed that for raw materials with particle sizes of 147~178 μm, CaC2 synthesis reaction can occur at 1500℃, and the reaction rate significantly increased when the temperature was above 1600℃. At 1600℃, the C2H2 yield and CaO conversion rate can reach up to 101~105 mL/g and 25%~26%, respectively. As the C:Ca molar ratio of raw materials was less than 9.6, the defluidization occured when the fluidized bed was operated at 1500~1600℃, and a large number of coke particles were found to adhere to the surface of CaO particle. The bed defluidization was caused by the particle agglomerates, which were formed through the sintering of CaO particles and bonding between CaO and coke particles. It was found that the former was the dominant factor causing defluidization, and increasing the concentration of coke particles in the bed can avoid this. Therefore, this study verified the feasibility of fluidized bed solid-phase CaC2 synthesis and provided a novel approach and data support for technological revolution in the field of CaC2 production. Related Articles | Metrics Select Bubble coalescence model considering bubble shape variations and bubble-induced turbulence Weibin SHI Shanshan LONG Xiaogang YANG Hui HUANG Nian DUAN The Chinese Journal of Process Engineering    2025, 25 (2): 169-178.   DOI: 10.12034/j.issn.1009-606X.224140 Abstract （85）   HTML （1）    PDF （3280KB）（34）       Knowledge map    Save For mathematical modelling of bubble coalescence, the cross-sectional area of the collision tube and the turbulent kinetic energy carried by the colliding bubbles are two key factors to determine the bubble coalescence rate due to turbulent collision. In most coalescence models, the shape of colliding bubbles is assumed to be spheric and the mean turbulent velocity correlation under shear turbulence (ST) condition is used to calculate the turbulent kinetic energy of the colliding bubbles. However, for the gas-liquid bubbly flow, the shape of bubbles transforms gradually from sphere to ellipsoid and spherical-cap with the increase of the bubble's volume. Furthermore, the influence of bubble-induced turbulence (BIT) has shown to be significant in the gas-liquid bubbly flow, especially along with the increase of the volume fraction of gas bubbles. When the bubble coalescence rate is calculated, the shape of bubbles affects the frequency of collision while the dominated turbulence mechanism affects the probability of a successful coalescence event. Based on the Prince and Blanch coalescence model, the present study proposed a coalescence model that considered the bubble shape variations as well as the joint effect of ST and BIT. Also, the turbulent kinetic energy transfer and the eddy-bubble response in the wake of spherical-capped bubble has been considered for the bubble coalescence due to BIT wake entrainment. Population balance model (PBM) has been used in the computational fluid dynamics (CFD) simulations for bubble columns to validate the proposed model. Comparisons have been made via simulation results of bubble size distributions (BSD) predicted by coalescence models with/without considering bubble shape variations and BIT. It is found that considering the shape of bubbles and the joint effect of shear turbulence and BIT, the proposed coalescence model significantly improves the prediction results of BSD and further affects the predictions of other important fluid dynamic parameters. Related Articles | Metrics Select Preparation of calcium carbonate nanoparticles by microbubble-enhanced carbonation Wenxin TIAN Hao DU Biao LIU Shaona WANG The Chinese Journal of Process Engineering    2025, 25 (2): 179-189.   DOI: 10.12034/j.issn.1009-606X.224147 Abstract （79）   HTML （2）    PDF （6269KB）（27）       Knowledge map    Save CO2 mineralization is a promising method for the resource utilization of low-grade limestone and calcium-containing solid waste. Therein, adopting the acetic acid medium to achieve indirect mineral carbonation process to fixing CO2 is considered as an innovative and environmentally sustainable method owing to the reusability of the acetic acid medium. Nevertheless, the conversion efficiency of carbonation in this technique remains limited, with less than 20% efficiency at pressure of 5 MPa. Even with the addition of an extractant for acetic acid, the conversion efficiency of carbonation is still below 30%, significantly impeding the industrial applicability of this technology. In order to address the low conversion efficiency of carbonation in the acetic acid system, this study developed a new method for the preparation of calcium carbonate nanoparticles by microbubble-enhanced carbonation. The impacts of various factors such as medium calcium concentration, reaction temperature, reaction time, the value of pH, and aperture size of aerator on the efficiency of the carbonation reaction were systematically investigated. The results showed that: (1) Under optimal conditions (reaction time of 1 hour, reaction temperature of 80℃, initial pH of 7.2, initial calcium content of 70.07 g/L, and aperture size of aerator of 0.22 μm), the conversion rate of carbonation can reach 19.17% under atmospheric pressure, equivalent to the conversion rate achieved under 3 MPa. Meanwhile the regeneration cycle of the acetic acid medium can avoid wastewater generation at the source. (2) By integrating tributyl phosphate (TBP) with microbubble technology, the conversion efficiency of carbonation was improved to 57.5%, marking a 13.4 percentage point improvement over the reported pressurized extraction process. (3) At atmospheric pressure, rod-like aragonite nano-calcium carbonate products were synthesized with length of 400~800 nm and width less than 100 nm. Related Articles | Metrics Select Research on behavior and mechanism of flotation entrainment of microfine-grained serpentine Jiajun LIU Guofan ZHANG The Chinese Journal of Process Engineering    2025, 25 (2): 190-200.   DOI: 10.12034/j.issn.1009-606X.224160 Abstract （53）   HTML （1）    PDF （4017KB）（23）       Knowledge map    Save In the flotation system of copper-nickel sulfide ores, fine-grained vein minerals, mainly serpentine, are very susceptible to be entrained into the concentrate with the froth, resulting in negative impacts on the concentrate product and the subsequent smelting process. In order to understand the influencing factors and whether there was any interaction in the process of froth entrainment of fine-grained serpentine and other vein minerals in the flotation system of copper-nickel sulfide ores, a response surface analysis (RSA) test was carried out on the basis of a one-factor test, and the effects of the interaction of the three factors, namely, foam agent dosage, gas volume velocity, and the foam layer thickness, were analyzed to determine the effects of the mechanical entrainment. The results of flotation entrainment showed that the foam agent dosage and pulp concentration affected the mechanical entrainment recovery of serpentine by influencing the water recovery and entrainment degree, while the gas volume velocity, particle size, and thickness of the foam layer only affected the entrainment degree and thus the recovery. The response surface test predictions were basically the same as the actual values, indicating that the predictions of the regression model were more accurate and can be used to analyze and predict the test results. The effects of the three factors investigated on the mechanical entrapment recovery of serpentine were foam agent dosage>foam layer thickness>gas volume velocity. Foaming agent dosage and foam layer thickness had significant influence on the mechanical entrainment of serpentine, which was a significant influence factor. The response surface method generally optimized the flotation conditions for the useful minerals rather than the vein minerals, and the interaction analysis showed that the different factors did not interact with each other on the mechanical entrainment of serpentine. Related Articles | Metrics Select Dissolution and separation of alumina from Guangxi high-iron bauxite Hao WU Shuhua MA Yanjun OU The Chinese Journal of Process Engineering    2025, 25 (2): 201-209.   DOI: 10.12034/j.issn.1009-606X.224050 Abstract （70）   HTML （0）    PDF （4373KB）（26）       Knowledge map    Save Taking the unserviceable Guangxi high-iron composite bauxite as the research object, a new three-step process is developed based on clarifying the occurrence forms of alumina in bauxite, the results indicates that they are gibbsite, boehmite, Al-goethite, hematite, anatase, quartz and so on. Among these, iron oxides includes 72.22wt% exists in the form of Al-goethite and 27.78wt% exists in the form of hematite, and the substitution rate of aluminium for iron in Al-goethite is 24.5 mol/mol; Alumina in bauxite exists in three forms, namely gibbsite, boehmite and Al-goethite, each accounting for 37.48wt%, 3.89wt%, and 42.46wt% of the total alumina. Firstly, extract alumina in the forms of gibbsite and boehmite under conditions of Na2O 100 g/L, reaction temperature 180℃, and reaction time 1 hour, which can be easily and completely dissolved, while Al-goethite mineral is difficult to transform under this mild conditions, as seriously affects the economy of this new process. In order to solve the problem of alumina dissolution in Al-goethite, low-temperature roasting is adopted to transform Al-goethite into hematite and activated alumina in order to solve the problem of aluminium leaching from Al-goethite based on the thermal transformation mechanism from goethite to hematite at a certain temperature. By roasting this iron-rich phase for 0.5 h at a temperature of 450℃, about 57wt% of the alumina in Al-goethite is released outside the hematite lattice, thus aluminium-iron separation and phase transformation are achieved. In the third step, the transformed minerals are dissolved again under the conditions of low alkali concentration (Na2O 100 g/L), reaction temperature of 220℃, and reaction time of 1 h. Under these conditions, the activated alumina outside the hematite lattice is dissolved. The total dissolution rate of alumina in the three-step process reaches 85.92%, and the iron oxide in the mineral is greatly enriched in the tailings after dissolution, and its iron oxide content reaches 83.06wt%, which can be used as raw material for ironmaking. Related Articles | Metrics Select Preparation and property of colourless polyimide composite films modified with two-dimensional polyaramid Zijian LI Renzhao WU Haifeng DONG Fenyun YI Yan WANG Defu CHEN Yufu CAI The Chinese Journal of Process Engineering    2025, 25 (2): 210-220.   DOI: 10.12034/j.issn.1009-606X.224184 Abstract （70）   HTML （0）    PDF （2403KB）（31）       Knowledge map    Save Colourless polyimide (CPI) is widely used as covers, substrates and touch panels for flexible displays, which require high glass transition temperatures (Tg), low coefficients of thermal expansion, excellent optical transparency and good mechanical properties. CPI is mainly obtained by introducing fluorine-containing groups to change the chemical structure of the molecular chain. This method of preparation allows for the production of CPI with high light transmittance, although it concomitantly results in a reduction in thermal and mechanical properties. By modifying two-dimensional inorganic materials, the thermal and mechanical properties of CPI can be effectively improved. However, technical difficulties such as poor compatibility with CPI and the complicated modification process also limit the application of two-dimensional inorganic materials in CPI modification. Therefore, a new method for modifying of CPI by a two-dimensional organic polymer, a two-dimensional polyaramid (2DPA) was proposed in this study, 2DPA/CPI composite films were prepared by the solution phase mixing method and the two-step thermoimide method. The structure and properties of 2DPA were analyzed, and the effects of 2DPA additives on the properties of 2DPA/CPI composite films, such as light transmittance, water absorption, Tg, and tensile strength were investigated. The results showed that without compromising the light transmission, the best effect was achieved when the addition of 2DPA in 2DPA/CPI composite films was 1wt%, and the Tg was increased from 338℃ to 358℃ compared to that of CPI films. The tensile strength reached 71.44 MPa, and elongation at break reached 4.34%, which were increased by 21.37% and 24.36%, respectively; and the water absorption rate was reduced by 39%, from 3.33% to 2.03%. The successful preparation of this CPI composite modified with two-dimensional organic material offers new ideas for the research and application of high-performance CPI-based composite materials, holding significant research value. Related Articles | Metrics Select Study of ammonium salt crystallization behavior in high pressure heat exchanger of hydrogenation unit Jianwen ZHANG Guoqing SU Leilei FENG Yan LI Fan ZHANG Shilin LU Yahui ZHAO Gang SHENG The Chinese Journal of Process Engineering    2025, 25 (1): 20-33.   DOI: 10.12034/j.issn.1009-606X.224129 Abstract （84）   HTML （3）    PDF （12054KB）（48）       Knowledge map    Save The problem of ammonium salt crystallization is very important for the safe production of the heat exchange system in hydrogenation plant, which often leads to blockage, corrosion leakage, and unplanned shutdown of the heat exchange system. It is of great significance to the study of the crystallization process and distribution characteristics of ammonium salt. In order to explore the problem of ammonium salt corrosion failure in the high pressure heat exchanger of diesel hydrogenation plant, the ammonium salt crystallization temperature was determined based on the concentration of components, and the C++ ammonium salt crystallization model and user-defined function (UDF) were written. Through isoparametric modeling of the heat exchanger, numerical simulations of the multiphase flow field, heat and mass transfer processes were carried out using ANSYS Fluent finite element analysis software and embedded UDF to analyze the intrinsic causes of corrosion failure. The mechanism of ammonium salt crystallization can be divided into heat transfer control and mass transfer control. The simulated ammonium chloride crystallization corrosion location and the actual corrosion coincided. The significant factors that influence the ammonium salt crystallization can be get through the orthogonal experimental analysis. The independence of the significant factors were analyzed to get the specific impact on the ammonium salt crystallization. Further, it provides a basis for the optimization of process device operation. Related Articles | Metrics Select Multi-objective parameter identification method for methanation reaction kinetics combined with process simulation Zhuohang JIN Xiaoxia HAN Fengyi LIU The Chinese Journal of Process Engineering    2025, 25 (1): 34-43.   DOI: 10.12034/j.issn.1009-606X.224091 Abstract （96）   HTML （4）    PDF （2530KB）（44）       Knowledge map    Save The simulation model of the methanation reactor can guide the optimization of the methanation process, which is of important research significance. However, the construction of the methanation reactor simulation model involves two parts: reactor modeling and reaction kinetics modeling, and the two models are coupled with each other. Neglecting the reactor transferring role and considering the kinetic model alone or solving the reactor model from the chemical equilibrium point of view without focusing on the kinetics will lead to low simulation accuracy, which makes it difficult to guide the optimization of the process effectively. The multi-objective optimization algorithm is used to identify the kinetic parameters of the methanation reactor model built in Aspen Plus, which can achieve high-precision identification of the parameters of the kinetic equation set with fewer data points, and the method can effectively solve the problem of identifying the parameters of the kinetic equation set in the complex reaction process by considering the reactor action and reaction kinetics at the same time. The results show that the multi-objective parameter identification method of the methanation reactor process simulation model can reduce the root-mean-square errors of CO conversion and CH4 selectivity simulation results to 1.96% and 4.59%, respectively, which are lower than those of the existing kinetic models. Related Articles | Metrics Select Preparation and characterization of abrasion-resistant core-shell alumina support used in fluidized bed reactors Yinhu ZHANG Zhanguo ZHANG Guangwen XU The Chinese Journal of Process Engineering    2025, 25 (1): 44-52.   DOI: 10.12034/j.issn.1009-606X.224170 Abstract （79）   HTML （4）    PDF （4021KB）（59）       Knowledge map    Save The Ni-based catalyst used in fluidized bed methane dry reforming reaction needs to have both high abrasion resistance and high activity, which requires the catalyst support itself to have both good abrasion-resistance and high Ni loading capacity. Based on the phase transformation mechanism of Al2O3, this study aims to prepare a type of core-shell @Al2O3 support with its shell in abrasion-resistant α-phase and its core in porous γ- or θ-phase Al2O3 through calcination of γ-Al2O3 at high temperatures. For this purpose, commercially available mesoporous γ-Al2O3 particles with a specific surface area of 325 m2/g and an average particle size of 850 μm were used as precursor material and calcinated in a vertical high temperature furnace at different temperatures for different periods of time. For prepared @Al2O3 samples, X-ray diffraction (XRD) analysis and N2 isothermal adsorption-desorption measurement were performed to characterize their phase transformation degree; electron microscopy (SEM) observation of their particles' cross-sections was conducted to confirm the formation of core-shell structure. And cold- and hot-state fluidized bed abrasion tests were carried out to evaluate their abrasion-resistance. The XRD results obtained have shown that the target core-shell @Al2O3 support can be prepared by calcination of porous γ-Al2O3 particles at 1250, 1300, and 1370℃ for different periods of time. SEM and BET characterization results also confirmed that the core-shell @Al2O3 particles with a shell thickness of 30~50 μm, a specific surface area of 86 m2/g and an average pore size of 22 nm were successfully prepared by calcination at 1300℃ for 6 min. The results of the fluidized-bed abrasion tests further confirmed that this core-shell @Al2O3 had the same excellent abrasion resistance as α-Al2O3, and the rate of its weight loss by abrasion at 800℃ was only 0.003wt%/h. At last, with this core-shell @Al2O3 as support, 10wt%Ni@Al2O3 catalyst was prepared in an impregnation approach and its abrasion resistance was evaluated at 800℃ to confirm that it also had the same resistance as α-Al2O3, which strongly suggests that such @Al2O3 supported catalyst has a good application prospect in fluidized bed reactor systems. Related Articles | Metrics Select Mechanism analysis of COSMO-RS screening ionic liquid to separate isopropanol-acetonitrile Jungang FAN Yue MENG Mingxin HE Jiarui HAO Wenxiu LI The Chinese Journal of Process Engineering    2025, 25 (1): 53-61.   DOI: 10.12034/j.issn.1009-606X.224115 Abstract （87）   HTML （3）    PDF （4905KB）（66）       Knowledge map    Save The efficient separation of alcohol-nitrile azeotropes produced in chemical production is a difficult problem in the chemical industry, and the widely used extractive distillation techniques in this field have put forward further requirements for the selection of extractants and mechanism analysis. The COSMO-RS model can be used to predict the thermodynamic properties of the fluid through quantitative calculation, and select the ionic liquids (ILs) extractant agent suitable for a certain system from a large number of possible solvents, which can significantly reduce the experimental amount and enhance the research efficiency. By comparing the model prediction value with the experimental value, the accuracy of the COSMO-thermX software in predicting the separation of alcohol and nitrile azeotropes by ionic liquid has been verified. Based on the COSMO-RS model, with the separation selectivity of ILs, the influence of ILs on the relative volatility of isopropyl alcohol (IPA)-acetonitrile (MeCN) near boiling point and the solubility of ILs to IPA as indexes, the effects of 456 ILs composed of 24 cations and 19 anions on the separation of IPA-MeCN azeotrope were calculated and analyzed. The results showed that ammonium tetraethylacetate ([N2,2,2,2][Ac]) was the best extractant. The interaction between IPA-MeCN molecules in the mixture and [N2,2,2,2][Ac] was studied by means of excess enthalpy analysis, interaction energy analysis and weak interaction analysis, and the separation mechanism of [N2,2,2,2][Ac] as an extractant for separating IPA-MeCN at molecular level was discussed, and the results showed that the interaction between [N2,2,2,2][Ac] and IPA was stronger than that with MeCN, thereby accelerating the disruption of the original azeotropic structure. The assistance of the COSMO-RS model in screening ILs extractants and analyzing separation mechanisms provided important information for further understanding the function of ionic liquid in azeotropic system separation, and had important reference value for the development of novel extractive distillation technologies. Related Articles | Metrics Select Mechanism and kinetics of alkaline leaching for low-grade bauxite activated by pre-roasting Tianxiang CHEN Haijun MA Kaifeng PANG Yuantao WANG Yifei ZHANG The Chinese Journal of Process Engineering    2025, 25 (1): 62-69.   DOI: 10.12034/j.issn.1009-606X.224137 Abstract （97）   HTML （5）    PDF （1329KB）（41）       Knowledge map    Save In recent years, as the production of alumina in China has sharply increased, the available high-quality bauxite resources have fallen short for alumina in China. Meanwhile, the amount of low-grade bauxite resources, i.e., containing high-sulfur and carbon, with a low aluminum-to-silicon ratio, is underused due to the lack of available technology. The depletion of high-quality bauxite resources and the utilization problem of low-grade bauxite ores have become the main bottlenecks restricting the sustainable development of the alumina industry in China. Therefore, the effective utilization of low-grade bauxite resources is of great significance for the sustainable development of the alumina industry in China. To solve this issue, the present study employed a potential process of sodium nitrate pre-roasting activation coupled with leaching in low-alkali solution for low-grade bauxite. The bauxite and pre-roasted clinker were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. The effects of technical parameters such as the temperature of pre-roasting bauxite alkali leaching, leaching time, and solid-liquid ratio on the leaching of alumina were studied in detail, focusing on the mechanism and kinetics of low-alkali leaching of pre-roasted bauxite. The results showed that after pre-roasting with sodium nitrate, the microstructure of the bauxite became loose, exhibiting a porous and grooved structure. Under the appropriate leaching conditions with a solid-to-liquid ratio of 300 g/L, using a lower concentration of caustic soda solution 160 g (Na2O)/L compared to the traditional Bayer process for 60 minutes at 270℃, 87.22% alumina of the pre-roasted bauxite with an original aluminum-to-silicon ratio of 3.57 was leached, and the aluminum-to-silicon ratio of red mud reduced to 0.88. This method could effectively improve the leaching rate of alumina in the bauxite and overcome the limitation of the theoretical leaching rate of Bayer process. The apparent activation energy for the leaching of alumina in the pre-roasted bauxite was regressed as 23.21 kJ/mol, the leaching process was controlled by mixed mechanisms. Related Articles | Metrics Select Effect of annealing on microstructure and mechanical properties of cold-rolled 430 ferritic stainless steel Shuaikang XU Xiaoyu SUN Lin CHEN Jinghui LI Mingya ZHANG The Chinese Journal of Process Engineering    2025, 25 (1): 70-79.   DOI: 10.12034/j.issn.1009-606X.224124 Abstract （93）   HTML （3）    PDF （2315KB）（18）       Knowledge map    Save After cold-rolled deformation of 430 ferritic stainless steel at room temperature with a 55% reduction, the annealing treatments were carried out at 800, 850, 900, 950, and 1000℃ for 15 min, followed by in?situ tensile and nanoindentation tests. The microstructure and mechanical properties of 430 ferritic stainless steel were studied by field emission scanning electron microscopy (SEM), electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). The results indicated when the annealing temperature increased from 800 to 850℃, the recrystallization proportion of the cold-rolled microstructure of the sample gradually increased, the recrystallization proportion increased from 66% to 68%, and the average grain size decreased significantly, from 9.23 μm to 8.07 μm. At this time, the microstructure of the sample was mainly affected by grain refinement, and the strength and plasticity of the sample were improved to a certain extent. The hardness also showed a certain degree of improvement. When the annealing temperature increased from 900℃ to 1000℃, the recrystallization ratio of the cold-rolled specimens increased from 71% to 89%, the average grain size increased by about 1.5 times, the dislocation density decreased significantly, the strength of the specimens decreased while the plasticity increased, and the hardness decreased significantly. When the sample was annealed at 850℃, the grain size in the structure is small and uniform, the yield strength reached 882 MPa, the elongation reached 17.5%, and the hardness value wass 2.08 GPa, indicating good microstructural and mechanical properties. Therefore, the optimal annealing process of 430 ferritic stainless steel was held at 850℃ for 15 min. Related Articles | Metrics Select Evolution of cementite in high strength pearlitic steel wires during drawing Yan WU Jianyu JIAO Fengmei BAI Hongwei ZHOU Gang ZHAO Jun XUE Guangwen ZHENG The Chinese Journal of Process Engineering    2025, 25 (1): 80-88.   DOI: 10.12034/j.issn.1009-606X.224150 Abstract （68）   HTML （7）    PDF （7618KB）（26）       Knowledge map    Save Cold-drawn pearlitic steel wire is widely used because of its high strength and certain toughness. In the process of cold drawing, the evolution of cementite lamellae has an important influence on the strength and toughness of steel wire. In this work, high-carbon steel wire rod with a diameter of 7.81 mm is selected, and the series of high-strength pearlite steel wires with different diameters are obtained by multi-pass cold drawing until the maximum true strain reached to 2.18. The evolution law and microscopic mechanism of cementite lamellae evolution during cold drawing are observed by transmission electron microscope (TEM) and scanning electron microscope (SEM) methods. The results show that during steel wire drawing, the longitudinal fibrous pearlite structure becomes more obvious with the increase of strain, and pearlite lamellae composed of ferrite and cementite are gradually adjusted to the drawing direction, and all of them are parallel to the drawing direction at the strain of 2.18. Complex changes have taken place in the cementite lamellae during drawing, which are characterized by lamellar refinement, bending and fracture in morphology, and polycrystalline, amorphous and nanocrystalline phenomena in microstructure. When the pearlitic lamellar orientation is nearly parallel to the drawing direction, interlamellar spacing gradually decreases, the lamellar arrangement direction gradually turns to the drawing direction, and the cementite lamellae become amorphous and nanocrystalline. When pearlite lamellae are nearly perpendicular to the drawing direction, cementite lamellae are bent, fractured and crystallized. At low drawing strain, dislocations mainly move in ferrite phase with a single slip, forming dislocation lines. At high strain, dislocations transform into multi-slip motions, generating dislocation tangles and dislocation cells, and some dislocations slip across the α-ferrite/cementite interfaces. Dislocation interacts strongly with cementite, and the lattice distortion in cementite increases, which is the main reason for the complex changes of cementite lamellae during cold drawing. Related Articles | Metrics Select Pilot investigation of catalytic oxidative removal of carbon monoxide from alumina industrial flue gas Xinglong GU Yang LI Changming LI Zijun GONG Huanyuan NING Ruijian TANG Jian YU The Chinese Journal of Process Engineering    2025, 25 (1): 89-100.   DOI: 10.12034/j.issn.1009-606X.224114 Abstract （78）   HTML （5）    PDF （7421KB）（38）       Knowledge map    Save The calcination process of the alumina industry usually produces nearly 10 000 mg/m3 CO in the flue gas during the combustion process due to low temperature or low excess air coefficient. Direct emissions not only causes energy waste but also causes harm to the local atmosphere. To explore the industrial application feasibility for catalytic elimination of CO from flue gas in alumina calcination, the manganese-cerium particulate industrial catalysts were prepared by co-precipitation method, and the pilot application study with flue gas volume of 1000 Nm3/h was carried out in an aluminum company of Shandong Province. The pilot test results showed that under the condition of low sulfur (<10 mg/m3), when the inlet temperature was 170℃, the CO removal rate was 80%~85%, and the removal rate was above 90% when the temperature was above 200℃. The catalyst was used in the pilot test to run continuously for 500 h at the inlet temperature of 190~200℃. It was found that there was no significant decrease in activity as a whole, indicating that the manganese-cerium catalyst had good stability in the purification of CO gas under actual working conditions. After 500 h of pilot-scale catalyst operation, the catalyst samples at different positions of the fixed bed were analyzed, and it was found that the catalyst performance at the flue gas inlet decreased slightly. The characterization results of typical samples such as XRD, TG, BET, SEM-EDS, and H2-TPR showed that the crystal diffraction peak of the catalyst sample at the flue gas inlet was enhanced, the specific surface area was decreased, and the sulfur deposition was increased, indicating that the local heating sintering and sulfur deposition were the main reasons for the partial deactivation of the catalyst. Related Articles | Metrics Select Modal visualization of heterogeneous condensation of water vapor on the surface of a single particle Xiangcheng WU Li LÜ Lijuan QIAN The Chinese Journal of Process Engineering    2025, 25 (1): 101-110.   DOI: 10.12034/j.issn.1009-606X.224142 Abstract （112）   HTML （5）    PDF （2501KB）（36）       Knowledge map    Save Heterogeneous condensation of water vapor on particle surfaces is a highly valuable industrial pretreatment technique for dust removal. Heterogeneous condensation of water vapor on particle surfaces can significantly improve the efficiency of dust removal. To study the dynamic behavior of droplets on the surfaces of particle during the process of heterogeneous condensation, the environmental scanning electron microscope (ESEM) is employed for visual observation of the heterogeneous condensation process of water vapor on particle surfaces. The evolution process of droplet mode is studied, and the contribution of line tension to the Gibbs free energy of the system during the condensation process and the influence of particle size and contact angle on line tension are analyzed. The results indicate that particles first nucleate to form a critical embryo droplet. This embryo droplet continues to grow and rapidly spreads to the equator of the particle. The droplet then remains on the equator, undergoing continuous condensation and growth, gradually transitioning to crossing the equator. With increasing condensation time, the droplet gradually envelops the particle. Once the particle is completely enveloped, the heterogeneous condensation transforms into homogeneous condensation and continuous growth. The entire condensation process can be divided into five modes: nucleation, diffusion, transition, encapsulation, and growth. The line tension of the five modes is analyzed, and it is found that when the droplet is in the upper hemisphere of the particle, the closer it is to the equatorial line, the greater the contribution of the line tension to the Gibbs free energy change of the system, which promotes its movement towards the equatorial line, and when it is in the lower hemisphere, it promotes its encapsulation of the particle. The effects of particle size and contact angle on the line tension are numerically studied, and it is found that the line tension increased with the increase of particle size. The influence of the intrinsic contact angle of the particle on the line tension is small, but the bigger the difference between the particle and the apparent contact angle, the greater the line tension. Related Articles | Metrics Select Design and heat transfer performance of impinging jet arrays for physical tempering of ultra-thin glass Zhijie LI Keqian ZHU Jinhan LIN Zhongqiang ZHANG Guanggui CHENG Jianning DING The Chinese Journal of Process Engineering    2024, 24 (12): 1387-1397.   DOI: 10.12034/j.issn.1009-606X.224106 Abstract （118）   HTML （3）    PDF （5215KB）（55）       Knowledge map    Save To meet the high-efficiency and uniform heat transfer requirements in the gas-suspended ultra-thin glass physical tempering heating furnace, a parametric design study on impinging jet arrays with return holes was conducted, particularly focusing on low jet heights. A three-dimensional numerical heat transfer model of high-temperature array jet impingement heat transfer was established, and the thermophysical properties of high-temperature gas were analyzed. Numerical simulations were conducted to investigate the effects of different design parameters on the transient heat transfer of impinging jets. Reynolds numbers (Re) ranging from 2000 to 10 000 were set. Under a certain mass flow rate, variations in the dimensionless reflux hole diameter (D1/D) from 1 to 3 and the dimensionless jet spacing (S/D) of 4, 5, and 7 were considered. Surface-averaged Nusselt number and temperature variation coefficient were used to illustrate the performance in terms of average heat transfer and uniformity. The results indicated that in the impinging jet array model with return holes at low jet heights, as Re varies from 2000 to 10 000, the surface average Nusselt number increased by 243.3%, and heat transfer uniformity improved by 90.9%. The diameter of the return holes had a significant effect on heat transfer. The ratio of the diameter of the return hole to the diameter of the jet hole (D1/D) increased from 1 to 3, and the average Nusselt number first increased and then decreased. When D1/D=2, the average heat transfer effect showed a turning point, and the average Nusselt number was always higher than that of the corresponding traditional array jet. A smaller return holes diameter led to a gradual reduction in the maximum velocity difference between the return holes and the jet holes, thus demonstrating excellent heat transfer uniformity. Additionally, reducing the ratio of jet holes spacing to diameter (S/D) improved heat transfer uniformity. At S/D=4 and D1/D=1, the heat transfer uniformity was maximally improved by 46.24% compared to the corresponding traditional array jet impingement. These research findings provide a theoretical foundation for the design and application of efficient impinging jet structures. Related Articles | Metrics Select Effect of jet angle on mixing performance of central multi-stranded jet reactor Ding WANG Zongyong WANG Lixun MA Aobang DING Zhanhua XU The Chinese Journal of Process Engineering    2024, 24 (12): 1398-1406.   DOI: 10.12034/j.issn.1009-606X.224111 Abstract （126）   HTML （2）    PDF （4901KB）（47）       Knowledge map    Save In order to explore the relationship between the relative flow direction and the mixing performance of the jet and the cross-flow of the central multi-strand jet reactor, the concept of three-dimensional jet angle represented by normal angle α and rotation angle θ was proposed and defined, and the mixing performance of various jet angles in space was simulated by fluent multiphase flow model. Firstly, the conditions of the numerical simulation were determined by the combination of numerical simulation and experiment, so as to ensure the accuracy of the simulation and conform to the regularity of the experiment. The results showed that under the mixture model, the concentration field obtained by the simulation was close to the distribution law obtained by the experiment, so the simulation can better reflect the internal concentration distribution of the reactor. Secondly, the reactor under the research angle was analyzed through the simulation, the qualitative analysis was carried out through the concentration contour of each section, and the quantitative analysis of the separation intensity of the cross-section, and the change law of the angle on the swirl intensity in the reactor were studied. It was found that θ=67.5° is the ideal rotation angle, and the reactors showed a good mixing effect at this angle. With the increase of θ, the pitch of the fluid trajectory at the mixing development section decreased gradually, and the swirling intensity increased gradually. The pressure drop of the inlet and outlet sections increased with the increase of the rotation angle, and the increase amplitude increased with the increase of the normal angle. At α=30°, θ=90° the slope of the separation intensity decreased the most, indicating that it can make the separation strength reach 0.05. With the increase of θ, the pitch of the mixed development section decreased and the swirling effect increased. The distance of the jet hitting the wall was proportional to the α and inversely proportional to θ. Related Articles | Metrics Select 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 （167）   HTML （2）    PDF （836KB）（42）       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 page Page 1 of 10 Total 390 records First page Prev page Next page Last page