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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 Fluid-particle and particle-particle drag forces in moderate-Reynolds-number bidisperse suspensions Fan DUAN Xuan HE Qiang ZHOU The Chinese Journal of Process Engineering    2024, 24 (3): 297-314.   DOI: 10.12034/j.issn.1009-606X.223212 Abstract （65）   HTML （2）    PDF （4989KB）（30）       Knowledge map    Save A set of fully resolved numerical methods are employed to simulate the bidisperse suspensions where the particles are free to translate and rotate according to the effects of the surrounding fluid, and the fluid-particle and particle-particle drag relations in the literature are examined. Three overall solid volume fractions of 0.1, 0.2, and 0.3, two diameter ratios of 1.5 and 2, three small-particle-phase fractions of 0.1, 0.3, and 0.5, four particle-to-fluid density ratios of 10, 100, 500, and 1000, and three overall particle Reynolds numbers of 10, 20, and 50 are chosen. Simulation results show that, among the fluid-particle drag relations available in the literature, in terms of the model accuracy, the relations obtained from static homogeneous systems are the best, the next are those of dynamic suspensions, and the monodisperse drag extended relations are the worst. Based on the simulation data, a new fluid-particle drag relation that meets all physical requirements is proposed. Further analysis reveals that the fluid-particle drag of bidisperse suspensions is influenced by five factors, that is the local solid volume fraction, the slip velocity between different particle phases, the granular temperature, the particle Stokes number, and the particle microstructure. Under the action of these factors, the change of the fluid-particle drag is not significant as the particle-fluid density ratio varies, and the difference of the fluid-particle drag between small and large particle phases is smaller than that in static homogeneous systems. For the particle-particle drag, when the particle-fluid density ratio equals 10 or 100, the collision numbers are unevenly distributed between different particle pairs because of the lubrication force. This uneven distribution of the collision numbers leads to the invalid of the assumption of molecular chaos, and for this reason, the particle-particle drag is highly overestimated by the relation derived from the kinetic theory of granular flow. Related Articles | Metrics Select Numerical simulation of multiphase flow process and structural improvement measures in the quench chamber of a gasifier Bing YUAN Jinjun GUO Xiaofei LI Junhui LIANG Zhenxiang Li Xiaodong LONG Congbin JIANG The Chinese Journal of Process Engineering    2024, 24 (3): 315-325.   DOI: 10.12034/j.issn.1009-606X.223196 Abstract （65）   HTML （3）    PDF （5039KB）（42）       Knowledge map    Save The entrained flow coal gasification technology is one of the important means for the clean utilization of coal. In the syngas cooling device, the quench chamber with riser-downcomer structure is widely used in the coal gasification device. There is a situation where synthetic gas escapes from the black water outlet in the quench chamber of this type of quench chamber, resulting in a waste of resources. In this work, the gas-liquid two phase flow in the quench chamber is stuided with the numerical simulation method. The causes of syngas escape problem from the black water outlet in the quench chamber are analyzed, and three improved structures for the quench chamber are proposed as follow: extending the black water outlet pipe (structure A), extending the riser pipe downwards (structure B), adding a baffle on the rising pipe near the black water outlet (structure C). The simulation results indicate that all three improvement schemes can avoid the problem of syngas escape. In addition, the liquid-solid two phase flow in the black pool with four structures (structures A, B, C, and the original structure) are simulated, and the carry-out rate of ash particles with different particle sizes under the same conditions are compared in different structures. The results show that the carry-out rate of ash particle in the improved structure C is the smallest, followed by the structure A. These two structural schemes are suitable for the situation where the residual carbon in the filter cake is not recycled, and the low carry-out rate of ash by black water is beneficial for improving the water quality of the water circulation system. Compared with the original structure, the structure B has a higher carry-out rate for particles size smaller than 20 μm, but a low carry-out rate for large particles, which is suitable for recycling the residual carbon in the filter cake. Related Articles | Metrics Select Numerical investigation on scale-up rule of circulating fluidized bed Jinchao XIE Nan ZHANG Tianbo FAN Xinhua LIU The Chinese Journal of Process Engineering    2024, 24 (3): 326-337.   DOI: 10.12034/j.issn.1009-606X.223135 Abstract （58）   HTML （11）    PDF （3613KB）（49）       Knowledge map    Save Circulating fluidized beds have been widely used in industry, and scaling laws have been proposed during research and development from lab-scale units to industry plants. The particle diameter ratio has to be changed to keep the scale-up ratio, which may change the particle classification from Geldart A to Geldart B and even change the fluidization regime, thus limiting the utilization of these scale-up rules. A new scale-up rule, which can keep material properties or operating conditions unchanged, is thus proposed based on the Shi scale-up rule applicable for the same circulating fluidized bed and the Horio scale-up rule suitable for different circulating fluidized beds. The Euler-Lagrange model coupled with the EMMS drag coefficient was used to simulate the flow behavior in a circulating fluidized bed, and the rationality of the Shi scale-up rule was further verified by these simulations. The new scale-up rule proposed was then validated under the conditions of fixed superficial gas velocity, fixed superficial particle diameter and unrestricted combination of the gas velocity and the particle diameter in different circulating fluidized beds. The simulation results showed that the proposed scale-up rule can maintain similarities in the axial solid concentration, radial solid concentration and radial dimensionless velocity distribution. The mesoscopic characteristic distributions were further discussed through the analysis of pressure fluctuations in the time domain and frequency domain. The results showed that the mesoscopic characteristics were different to some extent, which meant that more work should be done to keep the similarities when considering heat and mass transfer in circulating fluidized beds. Related Articles | Metrics Select Prediction of vapor-liquid phase equilibrium of nicotine+alcohol binary system based on COSMO-SAC model Furong DENG Changzheng JI Yapeng NIU Xiaomin FENG Xiangshi MENG Mengwei ZHANG Changjun PENG The Chinese Journal of Process Engineering    2024, 24 (3): 338-345.   DOI: 10.12034/j.issn.1009-606X.223182 Abstract （46）   HTML （2）    PDF （2728KB）（20）       Knowledge map    Save The phase equilibrium of the nicotine system holds great significance in guiding the separation and purification of nicotine, as well as exploring the release laws of nicotine and active ingredients in heated cigarettes. The conductor-like screening model-segment activity coefficient (COSMO-SAC) enables the prediction of phase equilibria and other properties through quantum chemical calculations. In this study, the vapor-liquid phase equilibria of nicotine with binary systems consisting of mono-alcohols (methanol, ethanol, n-propanol, isopropanol, butanol, pentanol, hexanol, heptanol, octanol) and poly-alcohols (ethylene glycol, 1,2-propanediol, 1,3-propanediol, and glycerol) are predicted respectively using the COSMO-SAC model. The results show that alcohol molecules exhibit peaks in both the donor and acceptor regions of hydrogen bonds, whereas nicotine only exhibits a peak in the acceptor region. This suggests that nicotine can only act as a hydrogen bond acceptor to receive protons and form hydrogen bonds. The nicotine-alcohol binary systems are all positive deviation systems; specifically, the binary systems of mono-alcohols and nicotine exhibit general positive deviation systems and show a similar phase diagram profile, however, as the number of carbon chains of alcohols increases, the area of the gas-liquid coexistence region becomes smaller; the binary systems of poly-alcohols and nicotine exhibit the azeotropic phenomenon, which is a system with minimum azeotrope. As the temperature rises, the pressure and composition of the azeotrope increase accordingly. At 101.3 kPa, the temperature and composition of the azeotrope are 511.4 K and 0.261 for glycerol/nicotine, 459.5 K and 0.857 for 1,2-propanediol/nicotine, 483.0 K and 0.727 for 1,3-propanediol/nicotine, and 467.0 K and 0.889 for ethylene glycol/nicotine. These research results provide theoretical data to guide the purification and separation of nicotine and to understand the release law of nicotine. Related Articles | Metrics Select Study on the removal mechanism of Zn(II) and Pb(II) by magnetic flake nZVI-Fe 3O 4 Shuxian WEI Canhua LI Wenqing MA Lanyue ZHANG Jiamao LI Aiqin MAO Chuan HE Minghui LI Weichang ZHU The Chinese Journal of Process Engineering    2024, 24 (3): 346-359.   DOI: 10.12034/j.issn.1009-606X.223189 Abstract （47）   HTML （2）    PDF （7924KB）（30）       Knowledge map    Save In response to the increasingly serious problem of heavy metal pollution in water bodies, engineering magnetic nanoparticles are widely used in wastewater treatment and remediation. In order to reduce the environmental pollution during the material preparation process, it is of great significance to improve its practicality in environmental protection technology. In this experiment, a new type of magnetic flake zero valent iron ferric oxide (nZVI-Fe3O4) with fissure structure was prepared by disproportionation. The physicochemical properties and structure of the material were characterized by multiple characterization techniques. The effects of pH, temperature, and the initial concentration of heavy metal ion solution on the removal efficiency of Zn(II) and Pb(II) by nZVI-Fe3O4 were studied. The experimental results showed that the removal of Pb(II) and Zn(II) by nZVI-Fe3O4 reached an equilibrium state in about 60 min. Under the conditions of a solution pH of 6, temperature of 25℃, and a dosage of 1 g/L of nZVI-Fe3O4, nZVI-Fe3O4 can reduce Zn(II) and Pb(II) in 10 mg/L simulated wastewater to trace levels within 5~30 minutes. As the pH value of the solution decreased, the adsorption efficiency of nZVI-Fe3O4 on Pb(II) decreased. The research results indicated that the removal process of nZVI-Fe3O4 followed the Langmuir model, indicating that it was a chemical adsorption process, and the maximum adsorption capacity of Zn(II) was 13.52 mg/g, while the maximum adsorption capacity of Pb(II) was 26.50 mg/g. Thermodynamic studies had shown that the removal process was spontaneous adsorption. The research results showed that nZVI-Fe3O4 mainly enriched Zn(II) and Pb(II) through adsorption co-precipitation. nZVI-Fe3O4 can be recovered through an external magnetic field, and experiments had shown that nZVI-Fe3O4 had good application prospects in removing Pb(II) and Zn(II) in wastewater treatment. Related Articles | Metrics Select Porous PLGA microsphere as a vaccine adjuvant against COVID-19 Lingjiao ZOU Yu ZHANG Hua YUE Guanghui MA The Chinese Journal of Process Engineering    2024, 24 (3): 360-370.   DOI: 10.12034/j.issn.1009-606X.223218 Abstract （58）   HTML （1）    PDF （1841KB）（26）       Knowledge map    Save Poly (lactic-co-glycolic acid) (PLGA) nano-/microspheres have been proven to be effective as vaccine adjuvants. In current studies, the investigations on PLGA vaccine delivery microspheres have mainly focused on improving antigen loading/adsorption efficiency or co-delivery of multiple adjuvants to enhance the immunization effect. However, there is still a lack of discussion on the impact of the structural diversity of microspheres in promoting the vaccination effects. By rationalizing the design of the microsphere structure, we describe that the development of an effective SARS-CoV-2 vaccine adjuvant was achieved by the post-loading of SARS-CoV-2 antigen into porous PLGA microspheres, which provided non-destructive loading and prolonged release of antigen. In this work, PLGA porous microspheres and solid microspheres were prepared with the emulsification method, and there was no significant difference in microsphere particle size and surface potential between the two, except for the porous microspheres having cavities internally and tiny pores on the surface. Such characteristics of "large inner pores and tiny outer pores" enabled the antigen encapsulation efficiency to reach 10.81% at the antigen input concentration of 5.71 mg/mL. In terms of prolonging the in vivo retention of the antigen, the release endpoint in the antigen-loaded porous microspheres was prolonged to 15 days compared with that of the free antigen at 3 days and that of the solid microsphere-mixed antigen at 5 days. Concerning the enhancement of humoral immunization, compared with the solid microsphere vaccine group mixed with SARS-CoV-2 antigen, the porous microsphere vaccine group loaded with SARS-CoV-2 antigen had a higher onset of effect as the maximum value of the IgG titer rising rate, Vmax was 1.73 times higher; and the onset of effect was much earlier, as the time to reach the Vmax was 2.8 days earlier; also, the IgG antibody titer of which was higher during 6~16 weeks post-immunization, presenting a better antibody maintenance effect. Related Articles | Metrics Select Deep mining of risk weaknesses for petrochemical processes based on alarm logs Yingqi ZHU Qianlin WANG Dongsheng ZHANG Zhan DOU Jianwen ZHANG The Chinese Journal of Process Engineering    2024, 24 (3): 371-380.   DOI: 10.12034/j.issn.1009-606X.223202 Abstract （42）   HTML （1）    PDF （1378KB）（19）       Knowledge map    Save There are highly dangerous factors in the complex petrochemical processes. The raw materials and products have the characteristics of flammable, explosive, toxic, or harmful. The major dangers would be easily caused by a slight carelessness. During the complex petrochemical processes, a great number of potential risk information is contained in the process alarm logs, which is conductive to reveal the root cause of danger incidents and prevent the occurrence of safety accidents. It is important to make full use of alarm logs for the complex petrochemical processes. Therefore, a deep mining method of risk weaknesses for petrochemical processes is proposed based on alarm logs in this work. Firstly, a word embedded technology-Word2Vec is introduced to pre-process the text-type alarm logs and make them to vectorial data, so the text-type alarm logs are converted and quantized. The Pearson correlation coefficient is further applied to analyze the relationship between these alarm logs and obtain the correlation matrix. Secondly, according to the theory of complex networks (CN), the correlation matrix should be transformed into a Boolean matrix, and then the risk character network could be established for complex petrochemical processes. Thirdly, the technique for order preference by similarity to an ideal solution (TOPSIS) is used to accurately assess the node importance of the established network model. This work involves three indicators: degree centrality, proximity centrality, and eigenvector centrality. Finally, the risk weaknesses of petrochemical processes can be deeply mined based on the priority of network node importance. A diesel hydrotreating unit is selected as the test case. Results show that the proposed method can accurately and effectively mine the process alarm logs with the alarm levels of "High High (HH)" and "High (HI)", which is consistent with the actual operating conditions of petrochemical processes. Related Articles | Metrics Select Chiller fault diagnosis based on combination of multiblock and self-attention TCN Yu SUN Qiang DING Yudong XIA Cong LI The Chinese Journal of Process Engineering    2024, 24 (2): 162-171.   DOI: 10.12034/j.issn.1009-606X.223174 Abstract （59）   HTML （2）    PDF （2476KB）（25）       Knowledge map    Save The energy consumed by HVAC systems accounts for 50%~60% of total building energy consumption worldwide, and various failures of chillers reduce the efficiency of HVAC systems by 15%~30%, resulting in a considerable amount of energy waste. Therefore, accurate detection of faults in chiller systems can effectively mitigate energy waste and extend the life cycle of the equipment. A fault diagnosis model based on multiblock and self-attention mechanism time convolution network (Multiblock Self-attention Temporal Convolutional Networks, MB-SATCN) architecture is proposed for the problem of difficult extraction of fault sample data feature information with high coupling and time correlation in chiller unit fault diagnosis. The model divides the overall variables into multiple sub-blocks based on the physical relationship between chiller sensors and system structure, and uses the time-convolutional network architecture to mine the feature information of chiller operation data in the sub-blocks. And by introducing the self-attention mechanism to enhance the weight of key features on the fault diagnosis results, the local features output from each sub-block are again weighted and fused using the self-attention mechanism to construct a global feature representation, and the final input global features into the fully connected layer for classification using the softmax function. The simulation results show that the introduction of MB method and SA mechanism effectively improves the feature extraction ability of highly coupled chiller unit fault samples and moreover improves the fault diagnosis performance of the model. Compared with the fault diagnosis performance of three deep learning methods dealing with time series, MB-SACNN, LSTM, and GRU, the MB-SATCN method performs the average accuracy of fault diagnosis under SL1 level of minor faults is up to 98.00%, the average recall rate is up to 97.90%, the average accuracy rate is up to 97.91%, and the F1-score is up to 98.00%, which verifies the sensitivity and stability of the method. Related Articles | Metrics Select Comparative analysis of heat transfer and flow resistance performance in typical twisted tubes Xiwen ZHOU Sen CHEN Xupeng WANG Huijie ZHU Xiuzhen LI The Chinese Journal of Process Engineering    2024, 24 (2): 172-181.   DOI: 10.12034/j.issn.1009-606X.223131 Abstract （71）   HTML （5）    PDF （3577KB）（32）       Knowledge map    Save In the literature survey on twisted tubes (TTs), it can be found that many documents believe that TTs are processed from round tubes based on the method of equal cross-sectional area, ignoring the fact that the cross-sectional perimeter of TTs is approximately constant during processing. In addition, the research on the cross-sectional shape on the heat transfer characteristics in the TT is relatively rare. Based on this, the heat transfer characteristics of the fluid in the TT with typical cross-sectional shape under low Reynolds number (Re) are analyzed by simulation on the basis of experimental validation. The results show the regularly spiral deformation of the TT induces periodic spiral flow of the fluid inside it, and the secondary flow is generated in the direction perpendicular to the mainstream, which reduces the synergy angle between temperature gradient and velocity and intensifies the convective heat transfer of the TT in contrast to that of round tube with equal cross-sectional circumference. When Re ranges from 650 to 1550, the TTs corresponding to the convective heat transfer coefficient from high to low are twisted triangle tube, twisted rectangular tube, twisted oval tube, twisted square tube and plain tube, respectively. The convective heat transfer coefficient and flow resistance of the twisted triangle tube increases 1.94~1.97 times and 2.96~3.06 times than plain tube, respectively. All the TTs outperform the plain tube in terms of comprehensive heat transfer performance and the comprehensive heat transfer performance evaluation factor of twisted triangle tube is the highest, with an average of about 1.86, and the rest are twisted rectangular tube, twisted oval tube and twisted square tube, which can be summarized that the twisted triangle tube performs the best convective heat transfer performance. Although the optimal tube shape is the twisted triangular tube, cold-rolling the cross-section into a triangular shape requires high toughness and is not easy to form. In practical applications, extruding the round tube into a rectangular or elliptical cross-section can be considered. The above research on the influence of cross-sectional shape on the heat transfer characteristics in TTs has practical significance for guiding the optimization design of novel TTs. Related Articles | Metrics Select Heat transfer characteristics of rectangular straight channel enhanced by curved streamline vortex generator Li ZHANG Kaili ZHANG Ying ZHANG Yaxia LI Jing ZHANG The Chinese Journal of Process Engineering    2024, 24 (2): 182-192.   DOI: 10.12034/j.issn.1009-606X.223101 Abstract （66）   HTML （0）    PDF （5243KB）（44）       Knowledge map    Save The longitudinal vortex generator is widely used as an effective passive heat transfer enhancement method. Vortex generators enhance the mixing between fluids by generating vortex motion, thereby improving heat transfer performance, but also generating flow resistance. Therefore, the development of longitudinal vortex generators with lower resistance and better overall performance is a research focus in this field. The geometric structure and placement position of the vortex generator are important factors affecting its comprehensive heat transfer performance. In this work, a curved streamline winglet pair (CSWP) vortex generator is proposed to improve the performance of the streamline vortex generator. The heat transfer characteristics in the rectangular straight channel where the curved streamline winglet pair vortex generator is installed are studied by numerical simulation, and the comprehensive strengthening effect of the curved streamline winglet pair vortex generator is evaluated. The influence of the shape, quantity, and installation position of the curved streamline winglet pair vortex generator on the heat transfer performance is investigated. The results show that in the range of Re=4000~26 000, compared with the plane delta wing winglet pair (PDWP) vortex generator, the curved vortex generator can effectively reduce the flow resistance, so it has a higher overall heat transfer performance. Compared with curved rectangular winglet pair (CRWP) and curved trapezoidal winglet pair (CTWP) vortex generators, CSWP vortex generators have better comprehensive strengthening effects. When the angle of attack is constant, the smaller the inclination angle of the leading-edge of the vortex generator, the more the quantity, and the better the comprehensive strengthening effect. The CSWP vortex generator has a streamline structure of the leading-edge that can significantly reduce the flow resistance and improve the synergy between the velocity field and the temperature field, which is the reason for its high comprehensive strengthening effect. Related Articles | Metrics Select Analysis of particle velocity distribution function in fast fluidization based on particle image velocimetry Dong XIAO Shanwei HU Xinhua LIU Li ZHANG The Chinese Journal of Process Engineering    2024, 24 (2): 193-206.   DOI: 10.12034/j.issn.1009-606X.223133 Abstract （82）   HTML （4）    PDF （4582KB）（51）       Knowledge map    Save Quantifying the heterogeneous gas-solid flow characteristics is of great significance to the design and optimization of this type of reactors. The formation and evolution of particle clusters result in the breakdown of the local equilibrium hypothesis, leading to the non-Maxwellian particle velocity distribution and the fail of classical kinetic theory of granular flow (KTGF). The particle movement characteristics and velocity distribution function in a fast fluidized bed were analyzed by using the experimental and data processing methods combing adaptive particle image velocimetry (PIV), particle tracking velocimetry (PTV) and digital image processing (DIA). It was found that the particle velocity distribution obviously deviated from the Maxwell distribution in both the gravity direction and the horizontal direction, showing a long-tailed off-peak or bimodal distribution. The bimodal distribution function can be used to fit the particle velocity distribution pretty well. In this work, the influence factors of anisotropy and non-Gaussian distribution characteristics of particle velocity distribution were further discussed. The particle velocity distribution function showed significant anisotropy in the horizontal and vertical directions. The deviation of particle velocity distribution function from the ideal distribution was positively correlated with the degree of particle clustering, the local particle velocity fluctuation and the particle concentration fluctuation, which may exhibit bimodal distributions in the near-wall regions. In order to analyze the relationship between particle velocity distribution function and mesoscale structure of fluidized bed more comprehensively, the energy-minimization multi-scale (EMMS) model was adopted to calculate the heterogeneous parameters. The consistency between the experimental results and the hypothesis of the dilute-dense phase coexistence showed the theoretical feasibility of the bimodal distribution. Related Articles | Metrics Select Numerical simulation on different vortex eliminator structures at end of riser of SVQS Wenwu YANG Ling QIN Ziwei HU Xiangyu WANG Hao LI Zhiliang ZHANG The Chinese Journal of Process Engineering    2024, 24 (2): 207-217.   DOI: 10.12034/j.issn.1009-606X.223173 Abstract （59）   HTML （2）    PDF （3746KB）（24）       Knowledge map    Save It was found that an unstable vortex zone existed in the upper space at the end of the riser of the super vortex quick separation (SVQS) system, which delayed the rapid draw-off of oil and gas and increased the risk of safe system operation. The velocity fields of SVQS system without vortex elimination plate, SVQS system with additional curved vortex elimination plate and SVQS system with new vortex elimination plate were analyzed, and it was found that the new vortex elimination plate improved the velocity field of the system, which in turn affected the separation performance of the system. The new vortex elimination plate reduced the pressure drop and the energy loss of the system without reducing the separation efficiency of the SVQS system. The concept of oil and gas residence time was introduced to analyze the specific residence time of oil and gas in the SVQS system, and it was found that the vortex elimination plate could reduce the residence time of oil and gas and fine particles in the system, and the residence time of oil and gas in the SVQS system with the addition of the new vortex elimination plate was smaller than that in the SVQS system with the addition of the curved vortex elimination plate. A comprehensive comparison revealed that the structure and performance of the new vortex elimination plate was superior and more informative for industrial applications. Related Articles | Metrics Select Quantum chemistry calculation of Al8O12 cluster model for adsorption mechanism of hydrogen fluoride on alumina surface Yajie TAN Xianwei HU Youjian YANG Aimin LIU Zhongning SHI Shuai TANG Zhaowen WANG The Chinese Journal of Process Engineering    2024, 24 (2): 218-226.   DOI: 10.12034/j.issn.1009-606X.223059 Abstract （74）   HTML （3）    PDF （3259KB）（31）       Knowledge map    Save In this work, the reaction process of alumina adsorption of hydrogen fluoride was studied by using quantum chemical theory. Density functional theory (DFT) was used to study the adsorption behavior of hydrogen fluoride molecule on the surface of cage-like cluster composed of four alumina molecules by using Gaussian. The appropriate approximate structures were obtained by scanning the system composed of alumina cluster and hydrogen fluoride molecule. The actual transition state structure was obtained by further optimization analysis of the structure. Based on this transition state structure, the intrinsic coordinate reaction (IRC) calculation was carried out to determine the adsorption reaction process and simulate the approximate adsorption reactant and product structure. The structures of reactant and product corresponding to both ends of the IRC curve were further optimized. In addition, the energy of reactant, transition state and product in the adsorption process was calculated by Shermo. According to the calculation results, the energy line diagram of the adsorption process was drawn. The bond order was calculated to analyze the change of chemical bond during the adsorption reaction. The results showed that the adsorption of hydrogen fluoride on alumina was chemical adsorption, and the total adsorption energy was -267.5 kJ/mol. There were two continuous stages of the adsorption process. The specific adsorption process was as follows. First, hydrogen fluoride molecule was dissociated. Fluorine atom and hydrogen atom were adsorbed on tricoordinate aluminum atom and its adjacent oxygen atom, respectively. At this time, the alumina cluster underwent certain deformation. Second, the hydrogen atom moved to bicoordinate oxygen atom, surmounted a potential energy barrier, and was adsorbed on it. In the process of hydrogen atom moving, the fluorine atom was adsorbed on the tricoordinate aluminum atom all the time. After the second stage of adsorption, the original deformed cluster was restored. According to the calculated value of the reaction equilibrium constant, it was thought that the adsorption reaction can occur spontaneously at room temperature. Related Articles | Metrics Select Adsorption properties of macroporous resin for organic pollutants in nickel-cobalt solvent extraction wastewater Bo XIANG Chenming LIU Renqiang CAO Feng DUAN Yuping LI The Chinese Journal of Process Engineering    2024, 24 (2): 227-237.   DOI: 10.12034/j.issn.1009-606X.223029 Abstract （79）   HTML （2）    PDF （2522KB）（51）       Knowledge map    Save Nickel-cobalt solvent extraction wastewater contains high salt and high organic pollutants, organic pollutants not only caused chemical oxygen demand (COD) to exceed the emission standard of pollutants, but also caused enormous problems such as generating a lot of foam, emerging difficulty in crystallization and producing waste crystalline salt in the evaporative crystallization process of wastewater, which seriously restricts the near-zero discharge of nickel-cobalt solvent extraction wastewater. In this study, the relationship between the structure and adsorption performance of macroporous resins (MARs) was explored by comparing the microstructure of four typical MARS and their adsorption capacity for organic pollutants in the nickel-cobalt solvent extraction wastewater. The study found that ORZ-A2 had the best adsorption capacity of organic pollutants and the single-stage static adsorption removal rate of total organic carbon (TOC) and total phosphorus (TP) were 70.79% and 83.11% respectively, which might be attributed to the reasonable pore size distribution and large specific surface area. Further, GC-MS was used to characterize the composition of organic pollutants of raw wastewater and adsorbed wastewater by MARs. It was found that the organic pollutants in nickel-cobalt solvent extraction wastewater were mainly organophosphorus extractants, their hydrolysates and derivatives represented by 2-ethyl-hexanoic acid. The four types of MARs had good adsorption effects on organophosphorus extractant and 2-ethyl-hexanoic acid, however, the organic pollutant in the adsorbed wastewater was mainly valeric acid, which indicated that the water-soluble small molecular organic pollutants represented by valeric acid might be the key to further enhance the removal rate of TOC. Subsequently, the kinetics study found that organic pollutants uptake onto four MARs followed the pseudo-second order model. The calculation results of thermodynamic parameters indicated that the adsorption of organic pollutants on MARs was a spontaneous, and exothermic physical adsorption process. This work provides a theoretical basis for guiding the industrial application of MARs adsorption technology for organic pollutants in nickel-cobalt solvent extraction wastewater. Related Articles | Metrics Select Separation of ethyl formate and ethanol azeotrope by extractive distillation using phosphate salt ionic liquid as extractant Chaoyue YIN Fan YANG Qinqin ZHANG Zhigang ZHANG The Chinese Journal of Process Engineering    2024, 24 (2): 238-247.   DOI: 10.12034/j.issn.1009-606X.223089 Abstract （75）   HTML （4）    PDF （1644KB）（50）       Knowledge map    Save In the process of producing ethyl formate with formic acid and ethanol as raw materials, the unreacted ethanol and ethyl formate will form an azeotrope, which is difficult to separate. In this work, the method of extractive distillation is used to separate the ethyl formate-ethanol azeotrope system with the ionic liquid as an extractant. The ionic liquid is screened by the COSMO-RS model, and the ionic liquid is determined to be 1-ethyl-3-methylimidazole diethyl phosphate ([EMIM][DEP]) and 1-butyl-3-methylimidazole diethyl phosphate ([BMIM][DEP]). The vapor-liquid equilibrium (VLE) data of the ethyl formate+ethanol binary system and the ethyl formate+ethanol+ ionic liquid ternary system are determined, and the experimental data are correlated with the NRTL model. Finally, the separation mechanism is explored by excess enthalpy analysis and σ-profile analysis (probability distribution of surface charge density). The results show that the relative volatility of ethyl formate increases with the increase in the molar fraction of two ionic liquids (ILs). When the ionic liquid concentration is 0.030, the relative volatility of ethyl formate to ethanol is greater than 1, and it can be seen that the separation effect of [EMIM][DEP] is better than that of [BMIM][DEP] ionic liquid. Through excessive enthalpy analysis, it is found that hydrogen bonds and van der Waals forces are more easily formed between ionic liquid and ethanol molecules, and the interaction between molecules is stronger than that between ionic liquid and ethyl formate, which promotes the separation of ethyl formate and ethanol. With the increase in ionic liquid concentration, the interaction between molecules is enhanced. Finally, the σ-profile analysis shows that ionic liquid is more inclined to interact with ethanol to separate ethyl formate, and it can be concluded that the shorter the cationic carbon chain of ionic liquid, the better the separation effect. Related Articles | Metrics Select Effect of additive Cu on performance of supported palladium catalyst for perfluoroolefin hydrogenation Junjie ZHANG Liantao JIANG Minmin LIU Xianglei MENG Guangwen XU Yanyan DIAO The Chinese Journal of Process Engineering    2024, 24 (2): 248-258.   DOI: 10.12034/j.issn.1009-606X.223108 Abstract （83）   HTML （6）    PDF （5195KB）（61）       Knowledge map    Save Hydrofluorocarbons have excellent characteristics of environmental friendliness, low toxicity, high stability, and are widely used in many fields, especially in the refrigeration industry, which has attracted great attention. Hydrofluorocarbons usually need to be prepared by hydrogenation of fluorinated olefins. However, due to the strong electronegativity of fluorine atoms, it is difficult to activate perfluoroalkenes, leading to perfluoroalkene hydrogenation is a challenging problem. For the hydrogenation reaction of perfluoroalkenes, precious metal supported palladium catalysts are currently widely used internationally, with a large palladium loading capacity and high cost. In this work, a high activity and low loading palladium catalyst with only 0.1wt% palladium content was prepared by impregnation method, and a series of copper promoted palladium catalysts were also prepared. The performance of different catalysts in the hydrogenation of hexafluoropropylene dimer were investigated on a micro fixed bed continuous reactor. The results showed that the 0.1wt% Pd catalyst also had good activity, the conversion of hexafluoropropylene dimer was 49.3%, and the selectivity of the target product was 97.6%. When 10wt% Cu promoter was used, the catalyst had the best activity, the conversion of hexafluoropropylene dimer was higher than 93.4%, and the selectivity of the target product could reach 98.6%. Through the characterization and analysis of XRD, H2-TPR, and XAFS technologies, it was found that the copper in the catalyst mainly existed in the form of Cu2O and Cu0. Cu2O could form a strong interaction with Pd, greatly reduced the reduction temperature of Cu2O in the catalyst through hydrogen overflow, and the hydrogen atoms overflowing from palladium could greatly improve the hydrogenation activity of hexafluoropropylene dimer. Therefore, this work provides a highly active, low-content and stable palladium-based catalyst for perfluoroolefin hydrogenation reaction and its preparation method, which provides a research direction for further design of efficient catalysts. Related Articles | Metrics Select Numerical simulation of non-oxidative methane dehydroaromatization reactor based on CPFD method Jinfeng SI Ming GONG Xiaojiao JI Xing LIU Xiaoxun MA The Chinese Journal of Process Engineering    2024, 24 (1): 17-26.   DOI: 10.12034/j.issn.1009-606X.223144 Abstract （103）   HTML （6）    PDF （1924KB）（100）       Knowledge map    Save Non-oxidative methane dehydroaromatization (MDA) is a promising technology for converting methane into high value-added products such as benzene, naphthalene, and hydrogen. The fluidized bed has good mass and heat transfer characteristics and is easy to realize the continuous regeneration of the catalyst, so it is an ideal MDA reactor. The basic research on fluidization in MDA fluidized bed reactors is one of the important links to realize the industrialization of MDA technology. In this work, the coupling model of reactions and hydrodynamics was established, and the fluidized bed reactor of the methane dehydroaromatization catalytic reaction/catalyst regeneration system, which has been constructed by our laboratory, was numerically simulated based on the computational particle fluid dynamics (CPFD) method. Then, the simulated values were compared with the corresponding experimental results, which validated the feasibility of CPFD simulation. Through simulation, the overall gas-solid flow state, the concentration distribution of each component in the gas phase and the catalyst carbon deposition content distribution were predicted. Finally, the effects of different operating conditions such as methane feed flow and catalyst retention in the reactor on the gas-solid two-phase flow and methane dehydroaromatization reaction performance were investigated. The results showed that the increase of methane feed flow rate reduced the methane conversion and improve the selectivity of aromatic products. Increasing the catalyst retention in the reactor can improve the methane conversion, meanwhile, it also made the axial and radial non-uniformity of the gas-solid two-phase distribution in the gas-solid reactor more significant, resulting in increased gas backmixing and lower the aromatic selectivity. This work would deepen the understanding of the gas-solid flow patterns inside the MDA fluidized bed reactor and provide some valuable data support for the industrial reactor scale-up of this technology. Related Articles | Metrics Select Effect of ore-coke coupling reaction on coke solution loss behavior Jiawei HAN Yang SUN Minghui DOU Rui GUO Zhang SUN The Chinese Journal of Process Engineering    2024, 24 (1): 27-35.   DOI: 10.12034/j.issn.1009-606X.223117 Abstract （79）   HTML （1）    PDF （2960KB）（40）       Knowledge map    Save The carbon peaking and carbon neutrality goals has proposed higher standards for the low carbon ironmaking of blast furnace. The evaluation of coke quality from the ore-coke coupling reaction is of great significance for understanding the reaction behavior of coke in blast furnace and reducing the carbon emission of blast furnace. To investigate the solution loss behavior of coke during the ore-coke coupling reaction, the ore-coke coupling experiment on two kinds of coke with different thermal properties with sinter and pellet were carried out by the home-made supported large-scale thermogravimetric detector. The carbon solution loss rate of coke and the ore reduction degree during reaction were analyzed, and the size, optical textures, and pore structures of cokes before and after the reaction were measured. The results showed that the total weight loss ratio of the coke-pellet coupling reaction was more than that of the coke-sinter coupling reaction, and the carbon solution loss rate of coke had a positive correlation with the reduction degree of ore. The slope k value of the fitting linear equation was proposed as the coupling reaction parameter to characterize the ore-coke coupling degree, and the k values of the coupling reactions between cokes and pellet were about 1.94~2.69 times higher than that of cokes and sinter, which indicated that improving the reducibility of ore can increase the coupling degree of the ore-coke co-reaction. Also, the greater coupling degree could aggravate the erosion of the pore wall on the surface of cokes and increased the solution loss and shrinkage degree of cokes, but it can weaken the erosion of the internal optical structures for cokes by the ore-coke coupling reaction. However, improving the reactivity of coke could reduce the k value of the ore-coke coupling reaction, and the coupling degree of the ore-coke co-reaction was weakened, which can mitigate the effect of ore-coke coupling reaction on the erosion of coke pores and reduce the solution loss and shrinkage degree of coke, but it can aggravate the erosion of the internal optical structure for cokes. Therefore, matching the performance of coke and ore can get the higher coupling degree of the ore-coke co-reaction, which can weaken the degradation of coke strength, and improve the efficiency of blast furnace. Related Articles | Metrics Select Reaction mechanism and process optimization of hydrogenolysis of hydrodebenzylation of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane Zijie GUO Bin ZHANG Jie CHEN Xin FENG Guilong WANG Weipeng ZHANG Chao YANG Wanqin JIN The Chinese Journal of Process Engineering    2024, 24 (1): 36-46.   DOI: 10.12034/j.issn.1009-606X.223070 Abstract （71）   HTML （3）    PDF （3080KB）（47）       Knowledge map    Save The key step in the preparation of hexanitrohexaazaisowurtzitane (HNIW) is the formation of hydrogenolysis of 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADBIW) by hydrogenolysis of hydrodebenzylation of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (HBIW) with a palladium-based catalyst in the presence of hydrogen. Due to the instability of HBIW, the caged structure of HBIW disintegrated easily in high temperature and acid environment, which was unable to be directly nitrified to synthesize HNIW. Therefore, hydrogenolysis debenzylation of HBIW is basically inevitable. In this process, hydrogenolysis debenzylation and acetylation occur simultaneously, the C-N bond is hydrogenated on the catalyst, and the subsequently formed amine is acetylated with the acetic anhydride. However, the process is complex and has many intermediate products. Current research is mainly focused on the development of new types of catalysts, with little knowledge of the dynamics and mechanisms of the reaction. This study established a new HPLC analysis method, and the concentration changes of raw materials and intermediates could be observed in the same chromatogram. Based on this, the effect of cosolvent and PhBr content on the hydrogenolysis reaction was studied. The reaction temperature was raised to 65℃, the reaction time was shortened to less than 1 h, and the yield reached 78.90%. Based on the optimal reaction conditions, the kinetics of the hydrogen dehumidification process at the reaction temperature of 18~45℃ were studied, and the concentration change law of each intermediate and reaction product in the reaction process was obtained through quantitative analysis and was inferred that the later stage was mainly acetylating. The process of converting raw materials into intermediates follows first-order reaction kinetics. The intermediate produces the product, following zero-order reaction kinetics; the apparent activation energies were Ea1=62.43 kJ/mol and Ea2=52.80 kJ/mol, respectively. The predigital factors were A1=6.81×109 min-1, A2=5.91×108 mmoL/min; The linear correlation coefficients were R12=0.99181, R22=0.98897. The continuous synthesis method was further developed, and the yield of TADBIW could reach 95.89% at a reaction temperature of 70℃ and a residence time of 4 min. Related Articles | Metrics Select Coal gasification slag modification process and its adsorption performance for Cd 2+ Ying XU Xinyi YAO Yonghong SONG Yiping SUN Jingjing ZOU Chunbin GUO The Chinese Journal of Process Engineering    2024, 24 (1): 47-57.   DOI: 10.12034/j.issn.1009-606X.222479 Abstract （78）   HTML （4）    PDF （5035KB）（43）       Knowledge map    Save Modified coal gasification slag (MCGS) adsorption material was prepared by hydrothermal method, by NaOH activation to remove Cd2+ from aqueous solution. Due to the low Cd2+ adsorption capacity of coal gasification slag (CGS), the modification conditions were optimized by Box-Behnken response surface method. X-ray diffraction (XRD) analysis revealed the presence of amorphous "steamed bread" SiO2 and residual carbon peaks in the range of 15°~30° in the coal gasification slag (CGS). These peaks had broad diffraction patterns. Fourier transform infrared (FTIR) spectroscopy showed that MCGS contained stretching and bending vibration peaks for the Si-O-T bond (where T is either Al or Si), indicating that the modified Si-O-Si bond had been broken and the vibration peak had increased. Scanning electron microscopy (SEM) images showed that the CGS mainly consisted of microbeads with smooth surfaces and flocculent or flaky blocks. The surface of the MCGS had an abundance of pores, with a specific surface area, pore volume, and pore diameter of 255.08 m2/g, 0.24 cm3/g, and 3.72 nm, respectively. The modification results showed that the best reaction conditions of MCGS were basicity 6.20%~8.10%, temperature 102~108℃, and time 138~192 min, and the temperature was the greatest influence on Cd2+ adsorption performance of MCGS. The adsorption results showed that when the concentration of Cd2+ was 50 mg/L and the dosage of MCGS was 0.10 g, the saturated adsorption capacity of Cd2+ was 13.96 mg/g; when the concentration of Cd2+ was 40 mg/L and the dosage of MCGS was 0.20 g, the removal rate of Cd2+ was 98.08%. The adsorption of Cd2+ on modified coal gasification slag follows a quasi second-order kinetic model, indicating that the adsorption of Cd2+ by MCGS was mainly chemical adsorption. The isothermal adsorption of Cd2+ onto the modified slag can be described well by the Langmuir model, indicating a monolayer adsorption process. This study can provide a theoretical basis for the treatment of Cd2+ wastewater with alkali-modified coal gasification slag. Related Articles | Metrics Select Study on dissolution of heavy metals from lead and zinc smelting waste acid slag Kai QIAN Shili ZHENG Ying ZHANG Hongming ZHOU Fen JIAO Shimin CHEN Shan QIAO Xing ZOU The Chinese Journal of Process Engineering    2024, 24 (1): 58-70.   DOI: 10.12034/j.issn.1009-606X.222439 Abstract （62）   HTML （6）    PDF （10827KB）（39）       Knowledge map    Save The heavy metal-containing waste acid slag generated in the lead and zinc smelting industry poses a considerable environmental risk. And at the same time it is also a resource. The purification of the calcium sulfate matrix is the first step for the downstream resource utilization of the slag. In this work, a comprehensive phase and composition analysis was carried out on the waste acid slag, and the distribution characteristics of the heavy metals and calcium sulfate in the slag were obtained. Then the effects of heating time, temperature and sulfuric acid concentration on the leaching rate of key elements such as Fe, Zn, As, Pb, Cd, and Sb were studied, and the dissolution rule of these key elements in acid medium was systematically explored. What's more, based on the general relationship between the crystal phase of calcium sulfate and the water activity and temperature, the effects of the phase transition as a result of the water activity regulation at atmospheric pressure or the hydrothermal environment in acidic medium on the dissolution of the metals were studied. The results showed that the effect was ideal when the heating time was 2 h, the heating temperature was 80℃, and the concentration of sulfuric acid was 1.0 mol/L. And the leaching rates of As, Zn, Sb, Cd, and Fe under the optimal conditions were all over 95%, with the leached CaSO4?2H2O residue showing smooth surface and in flake and rod mixed morphologies. Reducing the activity of water in the medium and hydrothermal conditions can promote the rotation of calcium sulfate. The dissolution of heavy metals in or between the crystal lattices of calcium sulfate can be further enhanced, assisted by the crystal transformation. As a consequence, the strengthened dissolution technology based on the crystal transformation of calcium sulfate is an effective way to purify the calcium sulfate matrix deeply. Related Articles | Metrics Select Experimental study on precipitation behavior of kish graphite during cooling of molten iron Yu GU Xuzhong GONG Xi LAN Lei GUO Zhancheng GUO The Chinese Journal of Process Engineering    2024, 24 (1): 71-78.   DOI: 10.12034/j.issn.1009-606X.223116 Abstract （68）   HTML （0）    PDF （4540KB）（29）       Knowledge map    Save The kish graphite separated from molten iron is a kind of sustainable resource. Because of the huge production of pig iron, this method of recovering kish graphite from molten iron has a broad prospect. In this work, the effects of blowing argon into the molten iron, different initial temperatures, and different cooling rates of molten iron on the precipitation behavior of kish graphite were investigated using scanning electron microscope, X-ray diffraction, and Raman techniques. The results showed that blowing argon into molten iron can effectively promote the floating and separation of kish graphite precipitated from molten iron. The initial temperature of molten iron had a significant effect on the amount and size of kish graphite precipitation, which mainly manifested that the higher the initial temperature, the flatter and smoother the surface of kish graphite, and the larger the size of precipitation, and the larger the amount of precipitation. The larger the cooling rate was, the less the amount of kish graphite precipitated and the smaller the kish graphite size was, and the kish graphite with a larger size can be obtained at a slower cooling rate. In addition, the precipitated kish graphite was used as lithium-ion anode material, which showed excellent cyclic stability and high specific capacity. In conclusion, kish graphite with different surface structures and sizes can be obtained by controlling the process conditions, which proved the feasibility of obtaining kish graphite by cooling molten iron. On this base, two new kish graphite production processes were proposed to provide a theoretical reference for the industrialization of kish graphite precipitated from molten iron. Related Articles | Metrics Select Preparation and biological safety evaluation of surface modified PET reticular fiber scaffold materials Yang LI Jianping GAO Yang ZHANG Qing PENG Yi GAO Guifeng ZHANG The Chinese Journal of Process Engineering    2024, 24 (1): 79-86.   DOI: 10.12034/j.issn.1009-606X.222462 Abstract （66）   HTML （2）    PDF （1240KB）（34）       Knowledge map    Save Using ammonia as plasma gas, the surface of synthetic polymer polyethylene terephthalate (PET) scaffold material was treated with low-temperature plasma, and a kind of reticular fiber scaffold material with improved hydrophilicity and biocompatibility was obtained. The material was characterized physically and chemically by XPS photoelectron spectroscopy, water contact angle, electron microscopy, and BET-specific surface area measurement. At the same time, hepatocytes were cultured to measure their biocompatibility, and in vitro cytotoxicity, intradermal reaction, and skin sensitization tests were carried out to evaluate their biological safety. The results showed that after low-temperature plasma treatment, N element was introduced into PET material. Compared with that before treatment, the percentage of O/C elements decreased by 2.05 percentage points, and the percentage of N/C elements increased by 2.10 percentage points. The water contact angle decreased from 123.32° to 30.55°, and the hydrophilicity was significantly improved. The surface roughness of PET material was increased after plasma treatment, and the specific surface area of the material was 0.37 m2/g. Plasma treatment can improve the biocompatibility of PET materials and promote C3A cell adhesion and proliferation. Compared with the untreated group, the treated group showed better biological activity. At the same time, PET-LTPT had good biological safety. MTT cytotoxicity assay in vitro showed that the cell survival rate of the PET-LTPT extract group was 135.82%, higher than that of the negative control group and blank group. It indicated that PET-LTPT material had no cytotoxicity in vitro. The results of the intradermal reaction test showed that the difference between the average score of PET-LTPT in different extraction media and the control group was less than 1.0, and there was no intradermal reaction. The skin sensitization test results showed that the PET-LTPT scaffold material did not produce delayed-type hypersensitivity to guinea pig skin. PET-LTPT is a potential three-dimensional liver tissue culture scaffold material for the bioartificial liver. Related Articles | Metrics Select Machine learning and process modeling of high moisture biomass gasification in downdraft gasifier Fenglei QI Zhen WANG Guoqing LU Xiaohao LIU Qi DANG Peiyong MA The Chinese Journal of Process Engineering    2024, 24 (1): 87-96.   DOI: 10.12034/j.issn.1009-606X.223114 Abstract （58）   HTML （2）    PDF （4384KB）（33）       Knowledge map    Save Biomass gasification is a potential pathway for thermochemically generating renewable producer gas, which serves as a good substitute fuel in heating and electricity section and is beneficial to the reduction of greenhouse gas emission. Biomass feedstock varies significantly in its composition, especially the content of moisture, posing a challenge for biomass gasification process design and operation in practice, however few research were carried out to elucidate the gasification principles of biomass with different moisture content. In this research, the effects of moisture content and process parameters on biomass gasification characteristics including syngas quality and energy balance are investigated by adopting machine learning and process modeling approaches. The prediction accuracy of the two approaches is first validated by comparing with experimental data. The obtained results indicate that the moisture content of biomass has a great negative impact on the low heating value (LHV) of produced gas, but does not significantly affect the carbon conversion efficiency (CCE) in the downdraft gasifier. The LHV of the produced gas decreases when the air equivalence rate (ER) increases due to the increment of carbon dioxide in the producer gas, but CCE increases with the increase of ER. The energy balance analysis suggests that ER increase with the increment of moisture content in biomass in order to maintain energy balance of the system. Pretreatment of biomass by drying is favorable to maintaining the quality of syngas, but the tradeoff is to consume a certain amount of producer gas to supply heat for the drying process. The consumption rate of the producer gas increases as the moisture content of biomass goes up, which is characterized by a nearly linear increase with the moisture content in the range of 20wt%~60wt% and an exponentially increment as the moisture content goes up beyond 60wt%. The current research provides fundamental insights on gasification characteristics of biomass with different moisture contents. Related Articles | Metrics Select Experimental study on atomization dust removal based on chemical wetting Shuoxin WANG Haiying LI Junya ZHANG Shaoqian LIU The Chinese Journal of Process Engineering    2024, 24 (1): 97-106.   DOI: 10.12034/j.issn.1009-606X.223086 Abstract （49）   HTML （1）    PDF （4354KB）（13）       Knowledge map    Save In view of the problems of nozzle clogging, large water consumption, uneven droplet size, and high energy consumption in the traditional wet atomization dust removal process, it was necessary to study the atomization characteristics of the dual-media nozzle used and its dust removal efficiency. The atomization dust removal method based on chemical wetting was studied, and the effects of wetting agent type, nozzle outlet structure, gas-liquid ratio and other factors on the removal efficiency of fine particles in converter flue gas in steel production process were analyzed. Firstly, the principle of wetting agent and the mechanism of water mist dust removal were analyzed. The effects of nozzle structure, gas-liquid ratio, and atomizing medium on atomization characteristics were experimentally studied. It was found that adding anionic wetting agents sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), nonionic wetting agents Trayton (TX-100), and Tween 20 (TW-20) in water can reduce the surface tension of the solution, of which SDS solution has the best wettability. With the increase of the wetting agent concentration, the SDS solution better reduced the surface tension of the solution and enhanced the primary atomization. During the atomization process, the dust reduction rate of the cone nozzle on PM10 can reach 41.91%. The droplet diameter gradually decreased as the gas-liquid pressure ratio increased, the droplet size of porous structure nozzle was smaller and more uniform compared with cone and sector nozzles. When the gas-liquid pressure ratio was 1.25, the atomization droplet SMD (Sauter Mean Diameter) of 0.05wt% SDS solution can reach 64.53 μm. The dust reduction rates of PM2.5 and PM10 can reach 74.28% and 76.41%. The research results can provide basic support for the pre-treatment and efficient dust removal technology of fine dust in traditional heavy industry such as steel, power, and building materials, and are of great significance for the efficient removal of PM2.5 and PM10. Related Articles | Metrics Select Intrinsic kinetics of CO methanation over spherical Ni/Al 2O 3 catalyst with high attrition resistance Shuo ZHANG Yu GUAN Yuanjiang YOU Junrong YUE Shihong PEI Yanbin CUI Jiao LIU Guangwen XU The Chinese Journal of Process Engineering    2024, 24 (1): 107-116.   DOI: 10.12034/j.issn.1009-606X.223080 Abstract （79）   HTML （3）    PDF （1827KB）（49）       Knowledge map    Save Carbon monoxide and hydrogen can be used to synthesize methane with catalyst application and this reaction is used in the field of coal to substitute natural gas, coke oven gas to liquid natural gas, and biomass synthesis gas to optimize the energy structure in China. Compared with fixed bed, the fluidized bed methanation technology adopting spherical catalyst with small diameters shows obvious superiority in activity and heat transfer efficiency due to the fast surface reaction characteristics of highly exothermic CO methanation. Based on the developed spherical Ni/Al2O3 catalyst with high attrition resistance, the intrinsic kinetics of CO methanation were tested in a differential fixed bed reactor under atmospheric pressure to reveal the reaction mechanism and route. The formation rates of CH4 at different ratios of CO/H2 and reaction temperatures were calculated on the premise of eliminating internal and external diffusion and controlling the CO conversion to less than 15% by decreasing the catalyst amount or increasing the gas feed rate. Then data fitting was conducted based on the power kinetic model and hyperbolic kinetic model, respectively. The results based on the power dynamics model showed that with the increase of reaction temperature from 260℃ to 350℃, the activation energy gradually decreased from 145.99 kJ/mol to 123.54 kJ/mol, the reaction order of CO changed from -1.22 to 0.34, and the reaction order of H2 increased from 0.31 to 2.28. To further analyze the methanation mechanisms, the rate-determining steps were assumed based on the hyperbolic dynamics model according to the effect of CO and H2 concentration on the reaction rate at different temperature ranges. As the rate determining step at 260~280℃ was assumed to be H2 dissociation, at 280~310℃ was the hydrogenation of CO and at 310~350℃ was the hydrogenation of carbon intermediate. The R2 of the hyperbolic rate equations obtained were all greater than 0.99, which indicated that the rate determining step of methanation would change with the temperature. Related Articles | Metrics Select Construction of Z-scheme CeO 2/Bi 2WO 6 heterojunction for efficient photocatalytic degradation of tetracycline hydrochloride Pingping WU Guanhua MENG Yu DU Baohe LIU Xu SHI Rui ZHOU Yongbin JIANG Huijuan ZHANG The Chinese Journal of Process Engineering    2024, 24 (1): 117-126.   DOI: 10.12034/j.issn.1009-606X.223053 Abstract （76）   HTML （3）    PDF （4390KB）（72）       Knowledge map    Save Tetracycline hydrochloride (TC), as a broad-spectrum antibiotic, is widely used in clinical medicine, animal husbandry, and aquaculture. It makes a large amount of TC wastewater discharged into the aquatic environment and ultimately endangers human health through the food chain. As an advanced oxidation technology, photocatalysis has significant advantages in refractory wastewater treatment. In this study, Bi2WO6 was prepared by the hydrothermal method, and the composite CeO2/Bi2WO6 was synthesized by doping appropriate CeO2 in Bi2WO6. The crystal structure, morphological characteristics, and light absorption performance were characterized. The results showed that the CeO2/Bi2WO6 ratio, catalyst dosage, initial concentration of TC, and initial pH value of the solution had a significant impact on the catalytic degradation of TC by photocatalysis under visible light. The formation of CeO2/Bi2WO6 heterojunction could effectively improve the separation efficiency of photogenerated electron-hole pairs, thereby greatly enhancing photoactivity. When the molar ratio of CeO2/Bi2WO6 was 1:3, the initial pH value was 5, the initial concentration of TC was 8 mg/L, and the dosage of CeO2/Bi2WO6 was 0.4 g/L, the removal rate of TC and TOC of the solution could reach up 90.7% and 64.3%, respectively. The possible photocatalytic degradation mechanism of TC over CeO2/Bi2WO6 was proposed according to the results of the free radical captured experiment and the potential value of the conduction band and valence band of the catalyst. After six cycle experiments, the removal rate of TC by CeO2/Bi2WO6 catalyst could still reach 86.4%. Related Articles | Metrics Select Flow characteristics of gas-liquid two-phase flow in microchannel with obstacles Yuanhao HUO Gang YANG Huichen ZHANG The Chinese Journal of Process Engineering    2023, 23 (12): 1617-1626.   DOI: 10.12034/j.issn.1009-606X.222454 Abstract （114）   HTML （9）    PDF （5399KB）（114）       Knowledge map    Save The obstacles in the microchannel have a significant impact on the pressure drop and bubble shape of gas-liquid two-phase flow. In this work, experimental and numerical simulation methods are used to explore the effect of obstacles in the channel on the movement characteristics of nitrogen/water gas-liquid two-phase flow in the microchannel. The variations of pressure drop and bubble length under different gas and liquid flow rates in microchannel with obstacles are analyzed. The results show that the pressure drop in the obstacle microchannel is higher than that in the barrier free microchannel, and the maximum pressure drop occurs with the obstacle in the center. Through numerical simulation analysis, this is due to the vortex generated after the obstacle, and the pressure drop is positively related to the vortex length. The bubble length of the obstacle microchannel changes within 25% compared to the barrier free channel, and the bubble length becomes shorter as the obstacle approaches the center. Under different flowing conditions, there are three phenomena when bubbles pass through obstacles, including retraction without rupture, retraction with rupture, and direct rupture without retraction. The retraction lengths increase with capillary number increasing in retraction without rupture. The retraction lengths reduce with capillary number increasing in retraction with rupture. When the retraction length decreases to 0, it become a direct fracture without retraction. The variation range of retraction length gradually increases as the obstacle approaches the center. When passing through all obstacles, different breaking and merging laws are displayed under different working conditions. By numerical simulation, different vortex lengths after the obstacle result in different pressure drops, and there exists sever change at the moment of bubble rupture. When passing through the obstacle, the change of bubble shape is affected by the change of liquid phase velocity around it, different velocities in the sub channels on both sides of the obstacle determine the different rules of the two sub bubbles after passing through the obstacle. Related Articles | Metrics Select Effect of fluid-structure interaction on liquid water flow in gas diffusion layer at microscale Jiemin WANG Sai ZHANG Qingtai WANG Xianjun WANG The Chinese Journal of Process Engineering    2023, 23 (12): 1627-1636.   DOI: 10.12034/j.issn.1009-606X.223096 Abstract （124）   HTML （6）    PDF （1468KB）（63）       Knowledge map    Save This work presents a new method to reconstruct the microstructure of carbon fiber gas diffusion layer (GDL), which is used to study the effect of velocity field in rough channels on GDL seepage. The random distribution model of pore channels in the diffusion layer is obtained by using the rough element and fractal theory. By distinguishing the hydrophilicity/hydrophobicity of the channel wall, four parameters, namely, the dispersion velocity ratio, the slip enhancement coefficient, the viscosity enhancement coefficient, and the microscale effect enhancement coefficient, are obtained. With accurate internal velocity distribution reconstructed as a control factor, and the effective seepage coefficient model is obtained by combining Darcy's law. The flow process of liquid water in GDL duct is simulated, and the influence of different roughness and contact angle on liquid water transmission performance is analyzed. The results show that the distributions of dispersion velocity, viscosity and slip velocity in the diffusion layer are affected by the random distribution of channel roughness elements and the non-uniform fluid solid interaction, and the four control factors act together on the flow process of liquid water and promote the discharge of liquid water. Under the same roughness, when the contact angle is 0o~180o, the promotion of hydrophilic wall slip effect conteracting the inhibition of dispersion effect and viscosity increases, and the promotion of hydrophobic wall slip effect conteracting the inhibition of dispersion effect and viscosity decreases, and the slope of flow change curve increases significantly at first and then decreases gradually. The newly established effective seepage coefficient model of liquid water in the diffusion layer can accurately describe the flow law in GDL, which has certain guiding significance for the internal water management of GDL. Related Articles | Metrics Select Finite element simulation of the effect of retaining ring on the slurry effective utilization in chemical mechanical polishing Pengyang QU Pan HUANG Cheng LIAN Shaoliang LIN Honglai LIU The Chinese Journal of Process Engineering    2023, 23 (12): 1637-1645.   DOI: 10.12034/j.issn.1009-606X.222460 Abstract （87）   HTML （0）    PDF （1753KB）（46）       Knowledge map    Save Chemical mechanical polishing (CMP) enables global and local flatness polishing of a wide range of materials and is now widely used in the field of integrated circuit manufacturing. As one of the main consumables in the CMP process, slurry accounts for 50% of the total cost of the CMP process. However, most of the slurry is discharged into the waste stream by centrifugal force before it reaches the polishing pad-wafer interface, resulting in a very low slurry effective utilization rate. Therefore, optimizing the CMP process parameters to improve the slurry effective utilization can not only reduce the polishing cost but also solve some environmental problems. For the CMP process, the retaining ring not only fixes the wafer to prevent it from slipping out but also helps the slurry to transfer between the pad-wafer interfaces through its multiple grooves to improve the slurry effective utilization. Consequently, in this work, construct a dynamic coupling model of slurry flow and retaining ring rotation, and the finite element method (FEM) was employed to investigate the effect of retaining ring structure (including the number of grooves, groove width, groove area, and the presence of rounded corners at the grooves) on the slurry effective utilization rate during the CMP process. The results showed that the slurry effective utilization rate improved with the increase of retaining ring groove number with the same groove width (3.0 mm). For the same groove area (1785.4±0.3 mm2), the increase of retaining ring groove number led to a decrease in the slurry effective utilization rate. And the same number of grooves, the larger the groove width, the greater the slurry effective utilization rate. Fillet grooves had a higher slurry effective utilization rate than sharp-edged grooves. When the groove width of the retaining ring was enlarged and the groove of the retaining ring was designed as fillet, the slurry effective utilization rate could be improved significantly. This work optimizes the CMP process parameters by FEM simulation and provides theoretical guidance to reduce the CMP cost. Related Articles | Metrics Select Study on preparation of sustained release microspheres with octreotide based on hydrophobic ion-pairing method Yu ZHU Yi WEI Donglin SUI Jingxuan LIU Fangling GONG Guanghui MA The Chinese Journal of Process Engineering    2023, 23 (12): 1646-1656.   DOI: 10.12034/j.issn.1009-606X.223064 Abstract （111）   HTML （7）    PDF （3357KB）（59）       Knowledge map    Save Octreotide (OCT) is widely used for the treatment of acromegaly, neuroendocrine tumors such as gastrinoma, and ruptured esophagogastric variceal bleeding in clinical. However, due to the short half-life of octreotide, the patients need frequent dosing in the treatment of diseases requiring long-term medication such as acromegaly, which leads to poor compliance. Therefore, it is urgent to develop a long-acting sustained-release formulation that can improve patient compliance. And since octreotide is a small molecule peptide drug that is extremely soluble in water, it tends to escape to the external aqueous phase during the preparation of microspheres, resulting in low drug loading and encapsulation efficiency. In this study, HIP-OCT complexes were prepared by hydrophobic ion-pairing (HIP) method. The effects of charge ratio, pH value, and temperature on the binding efficiency of the complexes were investigated, and the water solubility and dissociation of the complexes were observed. The sodium dodecyl sulfate-octreotide (SDS-OCT) with 93.77% binding efficiency, 9.31% water solubility, and 92.10% dissociation was screened as the optimal complex from the four HIP-OCT complexes. Due to the formation of HIP complexes, the hydrophilicity of OCT was changed and the difficulty of OCT encapsulation in double emulsion method was overcome. The SDS-OCT complex microspheres were prepared by the O1/O2/W double emulsion method combined with the premix membrane emulsification technique. Finally, the uniform SDS-OCT microspheres with particle size of 28.02 μm, Span value of 0.776, drug loading efficiency of 6.51%, and encapsulation efficiency of 72.00% were prepared under the negative pressure solidification, drug concentration of 80 mg/mL and poly(D,L-lactic-co-glycolic acid) (PLGA) concentration of 200 mg/mL. The in vitro accelerated release of the prepared SDS-OCT complex microspheres was basically in line with the trend of zero-level release, and the cumulative release was close to 100%. In vivo pharmacodynamic experiments showed that the microspheres had stable and long-term sustained release within one month. Related Articles | Metrics Select Effect of N-(β-ethyl sulfonate) aminoethyl sulfonate on crystal morphology of taurine Zhirong CHEN Gaojie DING Shenfeng YUAN Hong YIN The Chinese Journal of Process Engineering    2023, 23 (12): 1657-1666.   DOI: 10.12034/j.issn.1009-606X.223119 Abstract （85）   HTML （2）    PDF （2686KB）（36）       Knowledge map    Save The objective of this study was to investigate the effect of N-(β-ethyl sulfonate) aminoethyl sulfonate (SA), an inevitable impurity during the taurine production using the ethylene oxide synthetic route, on the morphology of taurine crystals (TCs). Crystal morphology was investigated under different SA concentrations and cooling rates, and the length-diameter ratio of TCs were statistically analyzed. The molecular dynamics simulation method was used to investigate the attachment of the SA molecules on TC faces and the reason for SA changing crystal morphology. The results showed that the average length-diameter ratio of TCs increased as the SA concentration and cooling rate increased. The dosage of 0.04 mol SA per kg H2O could bring in an more than 100% increase of the TCs average length-diameter ratio when the cooling rate was 30 K/h. An increase of approximately 3.8 times in the average length-diameter ratio was observed when the cooling rate increased from 6 K/h to 36 K/h with 0.02 mol SA per kg H2O added. The cooling rate in the crystallization process should be controlled to less than 12 K/h to obtain taurine products with an average length-diameter ratio less than 3. The simulation results showed that the presence of SA increased the attachment energy barrier of taurine molecules on all stable crystal faces and the crystal habit simulated by the modified attachment energy model was consistent with the experimental morphology. The reduction of (111 ?) face area ratio and the expansion of (102) and (102 ?) face area ratios were the fundamental reasons for high length-diameter ratio needle-like morphology of TCs in the presence of SA. In conclusion, this study provides insights into the role of SA in shaping the morphology of TCs and offers recommendations for optimizing the taurine production process. Related Articles | Metrics Select Oxidative refolding and purification of rhIFN-κ from the inclusion bodies Jiaqi WU Yuxiang ZHANG Luyao ZHANG Lingying YAN Rong YU Yongdong LIU Yao ZHANG Chun ZHANG The Chinese Journal of Process Engineering    2023, 23 (12): 1667-1675.   DOI: 10.12034/j.issn.1009-606X.223020 Abstract （82）   HTML （0）    PDF （1643KB）（33）       Knowledge map    Save Interferon-kappa (IFN-κ) has important biofunctions such as antivirus, antitumor, and immunomodulation. The unique secretion and physiological characteristics make it a promising medicine in clinical treatments. The recombinant human interferon-kappa (rhIFN-κ) expressed as inclusion bodies in E. coli require in vitro refolding to restore its biological functions, yet it tends to form precipitates in the process. Moreover, IFN-κ contains two disulfide bonds, but they are difficult to be correctly oxidized during the normal refolding procedure. In this work, a strong anionic surfactant, sodium dodecyl sulfate (SDS), was used to solubilize the inclusion bodies, and polyol 2-methyl-2,4-pentanediol (MPD) was added to the refolding buffer to gradually strip the SDS from the protein during the renaturation process to complete the refolding of rhIFN-κ. Experimentation showed that identified by the oxidative degree of its two disulfide bonds, there were mainly three species of rhIFN-κ after refolding: the completely oxidated rhIFN-κ, partially oxidated intermediate, and unoxidized species. For the SDS/MPD refolding system, the refolding yield for the correctly oxidated rhIFN-κ was closely related to the concentration and ratio of SDS and MPD in the renaturation system. Insufficient SDS or excessive MPD might result in forming aggregates or precipitates, while the correct oxidization of the disulfide bond would be suppressed at high SDS/MPD concentration ratios. Upon further optimization of the redox system and the solution pH, the optimal buffer was found by adding 0.05wt% SDS, 1 mol/L MPD, 0.2 mmol/L GSSG, and 0.1 mmol/L GSH to 20 mmol/L Tris at pH=9.5. Moreover, increasing protein concentration to 2.0 mg/mL would not significantly decrease the refolding yield. Under the optimized condition, the refolding yield could reach 66% after incubation for 24 hours at room temperature. Further purification with reversed-phase liquid chromatography could effectively remove the misfolded species as well as other impurities, achieving purity of 90% rhIFN-κ with only one band in non-reducing SDS-PAGE. The results showed that the SDS/MPD system could effectively suppress aggregation while increasing the rate of correct oxidization of the disulfide bonds. Our study lay a solid foundation for the production and clinical applications for rhIFN-κ in the future. Related Articles | Metrics Select Study on performance and mechanism of replaced stripping of light rare earth by Ce(Ⅳ) in nitrate solution Yi WANG Jian LI Mengling HUANG Xuxia ZHANG Hui ZHANG Tao QI The Chinese Journal of Process Engineering    2023, 23 (12): 1676-1684.   DOI: 10.12034/j.issn.1009-606X.223056 Abstract （85）   HTML （2）    PDF （3461KB）（49）       Knowledge map    Save The traditional solvent extraction leads to a large amount of acid-alkali consumption and saline wastewater discharge. Herein, a new strategy was proposed according to the different extraction ability of Ce(IV) and RE(III) with P507, driven by the oxidation and reduction of Ce. As one of the key procedure, the performance and mechanism of replaced stripping of light rare earth elements (LREEs) by Ce(IV) in nitrate solution was investigated in this study. Pr(III) was selected as the representative element of LREEs for the follow-up experiments. Several operational parameters such as phase ratio, temperature, reaction time, concentration of nitrate and Ce(IV) in aqueous feed, and acidity were investigated. Results indicated that the stripping efficiency of Pr(III) increased significantly with increasing temperature, reaction time and Ce(IV) concentration, while it decreased with the increase of phase ratio. The stripping efficiency of Pr(III) was 98% by 0.56 mol/L Ce(IV) under the optimal conditions, which was higher than that by 1 mol/L HCl solution. This method was generally applicable on the stripping of the other LREEs. The mechanism was explored by slope method and FT-IR spectrometric analysis. The solvation mechanism was carried out, and the key complexes in the organic phase before and after stripping were determined to be Pr(NO3)(HA2)2·(HA) and Ce(NO3)2A2, respectively. From the FT-IR spectrometric analysis, it can be concluded that the H in P-O-H was replaced by the rare earth, which was bonded with P=O. Nitrate was also involved in the reaction because of the presence of the characteristic peaks of nitrate. Related Articles | Metrics Select Preparation of low phosphorus content silicon from crystalline silicon sawing waste by slag refining method Lei JIN Xuefeng ZHANG Dong WANG Yong LIN Zhi WANG Guoyu QIAN Wenhui MA Kuixian WEI The Chinese Journal of Process Engineering    2023, 23 (12): 1685-1693.   DOI: 10.12034/j.issn.1009-606X.223042 Abstract （84）   HTML （0）    PDF （1870KB）（56）       Knowledge map    Save Crystalline silicon sawing waste is an important new energy solid waste. However, during the slicing and storage process, the surface of the silicon sawing waste tends to form a high melting point oxide layer, which makes the internal liquid silicon wrapped by the high melting point oxide layer during the high-temperature melting process, further resulting in longer melting time, high energy consumption, low silicon powder yield, and other challenges. Besides, low-quality silicon is recycled by the existing ordinary lime melting method due to phosphorus contamination of the silicon sawing waste from the electroplated diamond wire during the slicing process. Therefore, the silicon recycled from the melting of silicon sawing waste is a potential raw material for silicone production. In this work, silicon for organic use was successfully prepared by removing the surface oxide layer and non-metallic impurities of elemental phosphorus from crystalline silicon cutting scrap in one step using slag refining. Firstly, the high-temperature melting behavior of the oxide layer was simulated using silicon oxide. The effect of two slag systems, CaO-Al2O3-SiO2 and CaO-SiO2-CaF2, on the dissolution ratio of silicon oxide was compared. The influences of refining time (2~6 min) and refining temperature (1400, 1450, and 1500℃) on the dissolution ratio of silicon oxide were also investigated. Then, the effect of two refining slag systems on phosphorus removal was compared by using silicon sawing waste as raw material. The dissolution mechanism of the oxidation layer and phosphorus removal results were analyzed. The results showed that the dissolution of silicon oxide was mainly influenced by the viscosity of the refining slag system. The dissolution rate of silicon oxide can be improved by reducing the viscosity of refining slag. Compared with the CaO-Al2O3-SiO2 slag system, the dissolution rate of silicon oxide was faster in the CaO-SiO2-CaF2 slag system at the same conditions. The refining experiments showed that increasing the basicity of CaO-Al2O3-SiO2 and CaO-SiO2-CaF2 refining slag systems was beneficial to the phosphorus removal of silicon sawing waste. The maximum removal ratio of phosphorus was 53.81% and 62.04% for the two refining slags, respectively. Related Articles | Metrics Select Preparation of calcium-iron composite desulfurizer and its synergistic desulfurization effect Yang LIU Xinyu ZHANG Yang LI Changming LI Lina GAN Jian YU The Chinese Journal of Process Engineering    2023, 23 (12): 1694-1705.   DOI: 10.12034/j.issn.1009-606X.223068 Abstract （81）   HTML （4）    PDF （2557KB）（58）       Knowledge map    Save In this study, the calcium-iron composite desulfurized with high activity, large pore size, and high sulfur capacity was successfully developed by adopting hydroxyl-rich iron sludge as the structure and reaction additives, investigating the effects of different contents of iron sludge and anions on the desulfurization activity, aiming to address the key technical problems such as poor reactivity and low sulfur capacity of the fixed bed calcium-based particle desulfurized for flue gas with low exhaust emissions, while completing the utilization of red mud. The desulfurization performance test results showed that the calcium-iron dual component desulfurization agent exhibited a strong cooperating desulfurization effect, and the desulfurization performance was significantly higher than that of Ca(OH)2 or FeOOH individually, in which the 30wt% hydroxy iron oxide (FeOOH) desulfurization agent had the optimal sulfur capacity and better than the reported desulfurization agents of the same type, up to 106 mg SO2/g. N2 physisorption desorption, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, and thermogravimetric analysis characterization studied reveal that the structural basis of CaO desulfurizer synergistic desulfurization is the introduction of high specific surface area iron sludge during the hydroxylation process of CaO, which generated a highly reactive CaFeO3Cl·5H2O interfacial phase and inhibited the growth of Ca(OH)2 grains. In addition, the rapid evaporation and expansion of internal water during lime hydroxylation results in the formation of a porous, high specific surface area (67.36 m2/g) fluffy particle structure, exposing more abundant SO2 adsorption and reaction active sites, and the pore channels. Water film and active Fe3+ formed by the decomposition of FeOOH component of calcium-iron desulfurized during the desulfurization process effectively promoted the diffusion, adsorption, and oxidation of SO2, further enhancing the reaction and removal of SO2. This study is expected to be able to provide a cheap and convenient purification material and process for the desulfurization and purification of small and medium-sized boilers or bulk exhaust flue gas. Related Articles | Metrics Select Preparation of di-[EtPy][CoCl3] ionic liquid catalyst and coupling with oxone for desulfurization Xiaolong SONG, Shaokang WANG, Hang XU The Chinese Journal of Process Engineering    2023, 23 (12): 1706-1713.   DOI: 10.12034/j.issn.1009-606X.223008 Abstract （86）   HTML （2）    PDF （1722KB）（38）       Knowledge map    Save By leveraging its catalytic oxidation effect to remove dibenzothiophene (DBT) from model oil, a novel di-[EtPy]/[CoCl3] ionic liquid catalyzer was created using 1,4-dichlorobutane, pyridine, and cobalt chloride. The product was characterized by nuclear magnetic resonance (HNMR), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), and scanning electron microscopy (SEM-Mapping-EDS). This study constructed an extraction catalytic oxidation system (ECODS) using di-[EtPy]/[CoCl3] catalyst, ketone oxide (PMS) as oxidant, and acetonitrile as extractant to explore the catalytic activity and the removal effect of DBT in octane. The double-end structure of the double ionic liquid gave the catalyst a twofold chance of making contact with the oxidant once it was added, enhancing the release of the sulfate radical from the catalytic oxidant. Under the optimal desulfurization conditions: m(oil)=6 g, m(di-[EtPy]/[CoCl3])=0.10 g, m(acetonitrile)=1.00 g, m[PMS (20wt%)]=0.50 g, t=70 min, T=45.0℃, the removal rate of DBT in fuel oil could be as high as 96.86%. The analysis showed that the dipyridine ring of the catalyst strengthens the π bond and electrostatic interaction with DBT, and the double catalytic sites were the main reasons for the high catalytic efficiency. The desulfurization rate of di-[EtPy]/[CoCl3] catalyst after five cycles was more than 86.00%, which was mainly due to the interaction of ionic liquid and metal ions reducing the loss of catalyst. Finally, the oxidation product was identified as dibenzothiophene sulfone (DBTO2) by GC-MS, and the mechanism of the oxidation process was preliminarily discussed. The research showed that the di-[EtPy]/[CoCl3] ionic liquid as a catalyst had high catalytic activity and desulfurization performance, providing a new catalyst and process system for the industrial removal of DBT. Related Articles | Metrics Select Study on curing arsenic-containing compounds and solid wastes by iron-based silicate gel Boyu DU Chao LIU Xing ZHU The Chinese Journal of Process Engineering    2023, 23 (12): 1714-1724.   DOI: 10.12034/j.issn.1009-606X.223085 Abstract （103）   HTML （4）    PDF （2442KB）（64）       Knowledge map    Save During the mining and metallurgy of non-ferrous heavy metals, a large number of arsenic-containing compounds are exposed to the environment, posing great environmental risks to the surrounding water and soil. Due to their good arsenate affinity, iron ions and their compounds are the main components of commonly used chemical arsenic fixation agents. Whether in arsenic pollutant solidification or arsenic-contaminated site remediation, silicate and hydration processes are important physical barriers to arsenic. Based on this, we synthesized an iron-based silicate gel and evaluated its performance for the solidification/stabilization of typical arsenic compounds [Na3AsO4, Ca3(AsO4)2, AlAsO4, and FeAsO4·2H2O] and arsenic-containing sludge from non-ferrous metallurgy, and explored the arsenic fixation mechanism. The results showed that the iron-based silicate gel with a Fe/Si molar ratio of 1:4 could effectively immobilize the arsenic-containing compounds (Na3AsO4 and FeAsO4·2H2O). However, in the process of curing Ca3(AsO4)2 and AlAsO4, due to the competitive reaction between arsenate and silicate, the toxic leaching of arsenic was higher than that in the process of uncaring. The introduction of CaO could inhibit the competitive reaction, improve the arsenic fixation rate of Ca3(AsO4)2 and AlAsO4, and reach more than 98% of the arsenic fixation efficiency. The synergistic effect of Fe and Ca co-precipitation and physical immobilization is responsible for the immobilization/stabilization of arsenic-containing compounds. The core-shell structure with arsenic-containing compounds as the core and iron-based silicate gel/C-S-H gel as the shell separated arsenic species and reduced toxic leaching when in contact with the surrounding environment. The long-term stability showed that the iron-based silicate gel-cured arsenic-containing waste remained highly stable at pH=8 for 30 days. The CaO-assisted iron-based silicate gel proposed in this work showed great potential for the immobilization of arsenic-containing wastes and arsenic-contaminated land and provided a new way to solidify arsenic-containing pollutants. Related Articles | Metrics Select Forced oxidation of calcium sulfite and the influence of impurities in wet desulfurization by calcium carbide slag Yuewu ZHENG Ziheng MENG Lingxian LIAN Jiliang HAN Liwen ZHAO Xingguo WANG Gang XING Ganyu ZHU Huiquan LI The Chinese Journal of Process Engineering    2023, 23 (12): 1725-1738.   DOI: 10.12034/j.issn.1009-606X.223048 Abstract （171）   HTML （3）    PDF （9117KB）（110）       Knowledge map    Save The main component of calcium carbide slag (CCS) is calcium hydroxide [Ca(OH)2], which can replace limestone ore for wet flue gas desulfurization, but the desulfurization byproducts of calcium sulfite particles are small because of the strong alkalinity of CCS, which may affect the oxidation of calcium sulfite and the crystallization of calcium sulfate (CaSO4). The effects of different process conditions on particle size, oxidation rate, water content, and microcosmic appearance in the process of calcium sulfate oxidation and gypsum crystallization were systematically investigated, and the optimal process condition (calcium sulfate content of 5 g/L, aeration rate of 400 mL/min, initial pH value of 5.5, reaction temperature of 40℃, and reaction time of 4 h) was obtained. The byproduct of desulfurization gypsum (mainly calcium sulfate dihydrate) with large particle size, low water content, high purity, and uniform appearance was obtained under the optimal condition, which is conducive to the subsequent resource utilization of desulfurization gypsum. The leaching sequence of each element in the CCS under the actual operating pH conditions of the CCS slurry (acidic conditions) is Na>Ca>Mg>Si>Fe>Al. The effects of impurities of Na, Mg, Si, Fe, and Al in the CCS on the oxidation process of calcium sulfate and the crystallization of calcium sulfate were investigated under the above optimal reaction condition. The results indicated that Mg, Si, and Fe in the CCS had a significant promotion effect on the oxidation rate of calcium sulfate, while Al and Na in the CCS inhibited the oxidation of calcium sulfate. At the same time, the addition of Si impurity had almost no effect on the crystallization of calcium sulfate, the addition of the impurities of Mg, Fe, and Na had less effect on the crystallization of calcium sulfate, and the addition of Al impurity had a significant adverse effect on the crystallization of calcium sulfate. In this study, the CCS-based calcium sulfate was used as the raw material, and the study of calcium sulfate oxidation and gypsum crystallization was carried out, providing theoretical guidance for the forced oxidation process in the actual industrial desulfurization. Related Articles | Metrics Select Large eddy simulation for single particle wake characteristics in concave-wall tangential jet Jing ZHANG Wenhao HOU Chenghao ZHOU Zhiguo TIAN Bin GONG The Chinese Journal of Process Engineering    2023, 23 (11): 1497-1505.   DOI: 10.12034/j.issn.1009-606X.223019 Abstract （124）   HTML （4）    PDF （6139KB）（203）       Knowledge map    Save Large eddy simulation was used to simulate the influence of spherical particles near the wall on fluid flow characteristics under the action of tangential jets on the concave-wall. The simulated wake vortex results were in good agreement with the experimental tracer image. The vortex structure and its evolution process of particle wake with particle diameter dp=4 mm and radius of curvature of concave wall R=200 mm were studied. The changes of velocity, vorticity, and streamline around the particle were investigated at Reynolds number Re=700~10 000. The results showed that the vorticity in the influence area of particles increased, the peak value of vorticity always appeared on the upstream surface of particles, and the recirculation zone behind the particles shrank significantly with the increase of Reynolds number. When Re=700, there was only one wake vortex behind the particle along the concave wall jet spanwise. When Re≥2000, there were two wake vortices behind particles along the concave wall jet spanwise, and the tangential velocity and vorticity of the fluid fluctuated periodically. The particle lift and resistance were monitored. There was the vortex shedding frequency at Strouhal number St=0.000 854 when Re=2000, and the peak value of the lift power spectrum occurred at St=0.001 52. The frequency peak corresponding to the boundary layer and wake instability was not found in the drag power spectrum when Re=10 000, and the peak of the lift power spectrum occurred at St=0.008 74. The particle wake had a great influence on the flow field. The analysis of the particle wake characteristics in the tangential jet on the concave wall was an in-depth study of the liquid-solid two phase separation mechanism. It provided the theory for the characteristics of single particle wake vortex in the process of heterogeneous separation of the tangential jet from concave wall. Related Articles | Metrics page Page 1 of 8 Total 303 records First page Prev page Next page Last page