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SCI和EI收录∣中国化工学会会刊
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Table of Content
08 February 2025, Volume 78 Issue 2
    Advances in the preparation process and mechanism study of high-purity anhydrous magnesium chloride from magnesium chloride hexahydrate
    Hui Ming, Xudong Zhang, Xinping Huang, Lihua Cheng, Libo Zhang
    2025, 78(2):  1-23.  doi:10.1016/j.cjche.2024.10.016
    Abstract ( 25 )   PDF (18269KB) ( 375 )  
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    In the extraction of potassium from salt lakes, Mg is abundant in the form of bischofite (MgCl2·6H2O), which is not utilized effectively, resulting in the waste of resources and environmental pressure. Anhydrous MgCl2 prepared by the dehydration of bischofite is a high-quality raw material for the production of Mg. However, direct calcination of MgCl2·6H2O in industrial dehydration processes leads to a large amount of hydrolysis. The by-products are harmful to the electrolysis process of Mg, causing problems such as sludge formation, low current efficiency, and corrosion in the electrodes. To obtain high-purity anhydrous MgCl2, different advanced dehydration processes have been proposed. In this review, we focus on the recent progress of the dehydration process. Firstly, we discuss the molecular structure of MgCl2·6H2O and explain the reason why much hydrolysis occurs in dehydration. Secondly, we introduce the specific dehydration processes, mainly divided into direct dehydration processes and indirect dehydration processes. The direct dehydration processes are classified into gas protection heating and molecular sieve dehydration process. Indirect dehydration processes are classified into thermal dehydration of ammonium carnallite (NH4Cl·MgCl2·6H2O), thermal dehydration of potassium carnallite (KCl·MgCl2·6H2O), thermal decomposition of the [HAE]Cl·MgCl2·6H2O, organic solvent distillation, ionic liquid dehydration process and ammonia complexation process. In the meanwhile, purity of anhydrous MgCl2 of each dehydration process, as well as the advantages and disadvantages, is discussed. The characteristics of different processes with a simple economic budget are also given in this paper. Finally, the main challenges are evaluated with suggested directions in the future, aiming to guide the synthesis of high-purity anhydrous MgCl2.
    Oxygen distribution in bed and safety analysis during hydrogen purification process from oxygen-containing feed gas
    Lingbing Bu, Li Guo, Yingqi Luo, Wenhua Yin, Yi Wu, Hongyu Zhang
    2025, 78(2):  24-32.  doi:10.1016/j.cjche.2024.10.017
    Abstract ( 16 )   PDF (6523KB) ( 326 )  
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    In order to analysis the oxygen distribution in the adsorption bed during the hydrogen purification process from oxygen-containing feed gas and the safety of device operation, this article established a non-isothermal model for the pressure swing adsorption (PSA) separation process of 4-component (H2/O2/N2/CH4), and adopted a composite adsorption bed of activated carbon and molecular sieve. In this article, the oxygen distribution in the adsorption bed under different feed gas oxygen contents, different adsorption pressures, and different product hydrogen purity was studied for both vacuuming process and purging process. The study shows that during the process from the end of adsorption to the end of providing purging, the peak value of oxygen concentration in the adsorption bed gradually increases, with the highest value exceeding 30 times the oxygen content of the feed gas. Moreover, the concentration multiplier of oxygen in the adsorption bed increases with the increase of the adsorption pressure, decreases with the increase of the oxygen content in the feed gas, and increases with the decrease of the hydrogen product purity. When the oxygen content in the feed gas reaches 0.3% (vol), the peak value of oxygen concentration in the adsorption bed exceeds 10% (vol), which will make the front part of the oxygen concentration peak fall in an explosion limit range. As the decrease of product hydrogen content, the oxygen concentration peak in the adsorption bed will gradually move forward to the adsorption bed outlet, and even penetrate through the adsorption bed. And during the process of the oxygen concentration peak moving forward, the oxygen will enter the pipeline at the outlet of the adsorption bed, which will make the pipeline space of high-speed gas flow into an explosion range, bringing great risk to the device. The preferred option for safe operation of PSA for hydrogen purification from oxygen-containing feed gas is to deoxygenate the feed gas. When deoxygenation is not available, a lower adsorption pressure and a higher product hydrogen purity (greater than or equal to 99.9% (vol)) can be used to avoid the gas in the adsorption bed outlet pipeline being in the explosion range.
    Properties evolutions during carbonization of carbon foam using lignin as sole precursor
    Chen Liang, Weiqiang Chen, Linghong Yin, Xianli Wu, Jie Xu, Chunhua Du, Wangda Qu
    2025, 78(2):  33-43.  doi:10.1016/j.cjche.2024.10.013
    Abstract ( 13 )   PDF (14257KB) ( 325 )  
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    Lignin has been proved to be a promising precursor for producing carbon foam. The thermal and chemistry properties of lignin during its thermal conversion make it quite unique comparing with other precursors, and the conversion parameters can clearly affect the properties of the derived products. Therefore, this study systematically investigated the effects of key carbonization parameters on the properties of the resulting carbon foam materials. The findings demonstrate that the performance of the self-shaping lignin-derived carbon foam is simultaneously influenced by the factors that carbonization temperature, heating rate, and carbonization duration. Specifically, the carbonization temperature and carbonization duration have a significant impact on the mechanical performance, where higher temperatures and long carbonization time improve compressive strength and specific strength. Moreover, the data revealed that elevated temperatures, rapid heating rates, and shortened carbonization periods collectively promoted the development of higher porosities and larger pore diameters within the carbon foam structure. Conversely, lower carbonization temperatures, slower heating rates, and extended carbonization durations facilitated the formation of microporous in the carbon foam. This study provides a scientific foundation for optimizing the production of lignin-derived carbon foam with tailored properties and performance characteristics.
    Bubble breakup in viscous liquids at a microfluidic T-junction
    Hongwei Zhu, Junjie Feng, Ziyi Xu, Chunying Zhu, Youguang Ma, Wei Xu, Bing Sun, Taotao Fu
    2025, 78(2):  44-57.  doi:10.1016/j.cjche.2024.10.026
    Abstract ( 16 )   PDF (13305KB) ( 324 )  
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    Bubble breakup at T-junction microchannels is the basis for the numbering-up of gas-liquid two-phase flow in parallelized microchannels. This article presents the bubble breakup in viscous liquids at a microfluidic T-junction. Nitrogen is used as the gas phase, and glycerol-water mixtures with different mass concentration of glycerol as the liquid phase. The evolution of the gas-liquid interface during bubble breakup at the microfluidic T-junction is explored. The thinning of the bubble neck includes the squeezing stage and the rapid pinch-off stage. In the squeezing stage, the power law relation is found between the minimum width of the bubble neck and the time, and the values of exponents α1 and α2 are influenced by the viscous force. The values of pre-factors m1 and m2 are negatively correlated with the capillary number. In the rapid pinch-off stage, the thinning of the bubble neck is predominated by the surface tension, and the minimum width of the bubble neck can be scaled with the remaining time as power-law. The propagation of the bubble tip can be characterized by the power law between the movement distance and the time, with decreasing exponent as increased liquid viscosity.
    CO2-gasification of corncob in a molten salt environment
    Zhiying Feng, Kaifeng Liu, Tao Zhu, Dongfang Li, Xing Zhu
    2025, 78(2):  58-66.  doi:10.1016/j.cjche.2024.07.027
    Abstract ( 16 )   PDF (7856KB) ( 331 )  
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    Molten salt gasification is a promising technology for biomass conversion due to its advantages of superior heat transfer and the ability of utilizing solar energy to reduce carbon emission. In this study, the characteristics of corncob CO2-gasification in molten salt environments is thoroughly investigated, and the approach of introducing Fe2O3 as catalyst to enhance the syngas yield is proposed. The results showed that the molten salts significantly promoted the conversion of corncob into gaseous products with very low tar and char yield. Compared to O2 and H2O atmospheres, utilizing CO2 as gasifying agent enhanced the yield of gaseous products during the corncob gasification, especially the yields of CO and H2. The introduction of Fe2O3 as a catalyst could further increase the yield of gaseous products and the cold gas efficiency (CGE), and the yield of syngas was increased into 2258.3 ml·g-1 with a high CGE of 105.8% in 900 ℃. The findings evidenced that CO2 gasification in the molten salt environment with Fe2O3 addition can promote the cracking of tar, increasing the syngas yield significantly. Moreover, the energy required to drive the gasification process was calculated, and the total energy consumption was calculated as 16.83 GJ·t-1. The study opened up a new solution for the biomass gasification, exhibiting a great potential in distributed energy or chemical systems.
    Application of wavelet neural network with chaos theory for enhanced forecasting of pressure drop signals in vapor-liquid-solid fluidized bed evaporator
    Xiaoping Xu, Ting Zhang, Zhimin Mu, Yongli Ma, Mingyan Liu
    2025, 78(2):  67-81.  doi:10.1016/j.cjche.2024.10.010
    Abstract ( 15 )   PDF (22571KB) ( 291 )  
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    The dynamics of vapor-liquid-solid (V-L-S) flow boiling in fluidized bed evaporators exhibit inherent complexity and chaotic behavior, hindering accurate prediction of pressure drop signals. To address this challenge, this study proposes an innovative hybrid approach that integrates wavelet neural network (WNN) with chaos analysis. By leveraging the Cross-Correlation (C-C) method, the minimum embedding dimension for phase space reconstruction is systematically calculated and then adopted as the input node configuration for the WNN. Simulation results demonstrate the remarkable effectiveness of this integrated method in predicting pressure drop signals, advancing our understanding of the intricate dynamic phenomena occurring with V-L-S fluidized bed evaporators. Moreover, this study offers a novel perspective on applying advanced data-driven techniques to handle the complexities of multi-phase flow systems and highlights the potential for improved operational prediction and control in industrial settings.
    A parallel chemical reaction optimization method based on preference-based multi-objective expected improvement
    Mingqi Jiang, Zhuo Wang, Zhijian Sun, Jian Wang
    2025, 78(2):  82-92.  doi:10.1016/j.cjche.2024.11.004
    Abstract ( 17 )   PDF (8414KB) ( 116 )  
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    Optimizing chemical reaction parameters is an expensive optimization problem. Each experiment takes a long time and the raw materials are expensive. High-throughput methods combined with the parallel Efficient Global Optimization algorithm can effectively improve the efficiency of the search for optimal chemical reaction parameters. In this paper, we propose a multi-objective populated expectation improvement criterion for providing multiple near-optimal solutions in high-throughput chemical reaction optimization. An l-NSGA2, employing the Pseudo-power transformation method, is utilized to maximize the expected improvement acquisition function, resulting in a Pareto solution set comprising multiple designs. The approximation of the cost function can be calculated by the ensemble Gaussian process model, which greatly reduces the cost of the exact Gaussian process model. The proposed optimization method was tested on a SNAr benchmark problem. The results show that compared with the previous high-throughput experimental methods, our method can reduce the number of experiments by almost half. At the same time, it theoretically enhances temporal and spatial yields while minimizing by-product formation, potentially guiding real chemical reaction optimization.
    Solid-liquid phase diagram of the KNO3-Ca(NO3)2-Mg(NO3)2-H2O system at 313.15 K
    Xiangxia Zeng, Tao Zhang, Li Lv, Wenxiang Tang, Zongpeng Zou, Shengwei Tang
    2025, 78(2):  93-107.  doi:10.1016/j.cjche.2024.11.002
    Abstract ( 15 )   PDF (13113KB) ( 109 )  
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    The enrichment of low-grade phosphate rock is an important process to realize sustainable support of phosphorus resources. An aqueous solution containing Ca(NO3)2 and Mg(NO3)2 is produced during the enrichment of low-grade phosphate rock by leaching of HNO3 or calcination coupling with leaching of NH4NO3 solution. Preparation liquid fertilizer is a preferential way to utilize it. The liquid-solid phase diagrams of Ca(NO3)2-Mg(NO3)2-H2O, KNO3-Mg(NO3)2-H2O, KNO3-Ca(NO3)2-H2O and KNO3-Ca(NO3)2-Mg(NO3)2-H2O systems at 313.15 K were studied by isothermal dissolution equilibrium method. Two crystallization regions of Ca(NO3)2·4H2O and Mg(NO3)2·6H2O were observed in the phase diagram of the ternary system Ca(NO3)2-Mg(NO3)2-H2O, a liquid fertilizer with a maximal total nutrient content of 27.46% and a nutrients ratio of N:Ca:Mg = 8.40:10.37:1 can be formed. A homogenous solution can be formed by mixing Ca(NO3)2·4H2O and Mg(NO3)2·6H2O. In the ternary system KNO3-Mg(NO3)2-H2O, the crystallization regions of KNO3, Mg(NO3)2·6H2O and the co-crystallization region of KNO3 and Mg(NO3)2·6H2O were observed. The obtained maximal total nutrient content of liquid fertilizer is 23.32% with the ratio of N:K2O = 1:3.39. In the ternary system KNO3-Ca(NO3)2-H2O, the crystallization regions of Ca(NO3)2·4H2O and KNO3 were observed. The obtained maximal total nutrient content of liquid fertilizer is 38.41% with the ratio of N:K2O:Ca = 1.05:1.18:1. A homogenous solution can also be formed by mixing Ca(NO3)2·4H2O and KNO3 directly. In the quaternary system KNO3-Ca(NO3)2-Mg(NO3)2-H2O, the crystallization regions of Ca(NO3)2·4H2O, Mg(NO3)2·6H2O and KNO3 and the co-crystallization region of KNO3 and Mg(NO3)2·6H2O were observed. The obtained maximal total nutrient content of liquid fertilizer is 38.41% with the ratio of N:K2O:Ca = 1.05:1.18:1. The modified BET model was successfully used to fit the solubility curves. The results can provide a guidance for the formulation of water-soluble fertilizers of N-(K, Ca, Mg).
    Micromixing efficiency and enhancement methods for non-Newtonian fluids in millimeter channel reactors
    Zhaoyi Song, Yuanxi Zhang, Guangwen Chu, Lei Shao, Yang Xiang
    2025, 78(2):  108-119.  doi:10.1016/j.cjche.2024.08.006
    Abstract ( 18 )   PDF (8349KB) ( 149 )  
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    Millimeter channel reactors (MCRs) have received increasing attention because of their ability to enhance treatment capacity in addition to the advantages of microchannels. In previous studies, less work has been conducted on the micromixing process and enhancement strategies for non-Newtonian fluids in MCRs. In this study, the micromixing efficiency in MCRs was experimentally investigated using CMC (carboxymethyl cellulose sodium) aqueous solution to simulate a non-Newtonian fluid, and the enhanced mechanism of micromixing efficiency by the addition of internals and rotation was analyzed by computational fluid dynamics (CFD) simulations. The results show that in the conventional channel, increasing the flow rate improves the micromixing efficiency when the CMC concentration is low. However, when the CMC concentration is higher, the higher the flow rate, the lower the micromixing efficiency. The highest micromixing efficiency is obtained for the rotationally coupled inner components, followed by the single rotation and the lowest is for the internals only. CFD simulations reveal that the most effective way to improve the micromixing efficiency of non-Newtonian fluids with shear-thinning behavior is to increase the shear force in the reactor, which effectively reduces the apparent viscosity. These results provide the theoretical foundation for enhancing the micromixing process of non-Newtonian fluids in small-size reactors.
    Particle bond destruction based on spiral-cyclone coupling mechanism for the cementation of hydrates and mud–sand
    Yang Tang, Qing Gu, Na Xie, Yufa He, Yunjian Zhou, Zeliang Li, Guorong Wang
    2025, 78(2):  120-130.  doi:10.1016/j.cjche.2024.10.024
    Abstract ( 17 )   PDF (13179KB) ( 29 )  
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    Weak cementation between natural gas hydrates and mud–sand seriously affects the solid-fluidized mining of natural gas hydrates. In this study, we analyze the debonding of natural gas hydrate sediment (NGHS) particles by applying the principle of spiral-cyclone coupling separation. To achieve this, weakly cemented NGHS particle and mechanical models were established. In the flow field of the spiral-cyclone flow-coupling separator, the motion characteristics of the weakly cemented NGHS particles and the destruction process of the cementation bond were analyzed. The destruction of the bonds mainly occurred in the spiral channel, and the destruction efficiency of the bonds was mainly affected by the rotational speed. Collision analysis of the particles and walls showed that when the velocity is 10–16 m·s-1, the cementation bond can be broken. The greater the speed, the better the effect of the bond fracture. The breaking rate of the cementation bonds was 85.7%. This study is significant for improving the degumming efficiency in natural gas hydrate exploitation, improving the recovery efficiency of hydrates, and promoting the commercialization of hydrate solid fluidization exploitation.
    Enhanced visible-light-driven CO2 photoreduction into methanol using PtO/GdFeO3 nanocomposites
    Ali Fawad, Zaman Saeed, Yimeng Sun, Xu Zhang, Feng Zhang, Guodong Li, Guangli Yu
    2025, 78(2):  131-139.  doi:10.1016/j.cjche.2024.10.025
    Abstract ( 20 )   PDF (13262KB) ( 20 )  
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    Herein, PtO-supported GdFeO3 (PtO/GdFeO3) composite photocatalysts were synthesized by a solution-based technique. Extensive analysis using various analytical instruments has shown that PtO plays a crucial function in augmenting the visible light absorption capacity of composites. Better photogenerated charge carrier transport was credited with this improvement, which led to a decrease in bandgap energy as low as 2.14 eV. The PtO/GdFeO3 nanocomposites showed remarkable photocatalytic activity when exposed to visible light, especially in the conversion of CO2 into CH3OH. After 9 h of light, a noteworthy yield of 1550 μmol·g-1 of methanol was produced, demonstrating maximum efficiency at a dose of 2.0 g·L-1 and a concentration of 5.0% PtO/GdFeO3. This yield indicates the effectiveness of the heterostructure, which outperformed pristine GdFeO3 by a factor of 7.85. This significant enhancement highlights the potential advantages of the modified structure in improving performance. Most significantly, the photocatalyst's durability maintained 98.0% of its initial efficacy throughout five cycles. The success of PtO/GdFeO3 is largely due to the synergistic light absorption capabilities and enhanced photocharge carrier separation that the integration of PtO produced. It highlights the conversion of CO2 into valuable chemicals under visible light exposure, as well as the promise of mixed oxide nanostructures in ecologically responsible material creation.
    Regional collaborative allocation of emergency resources for enterprises within a chemical industry park based on the worst credible accident scenarios
    Shangzhi Liu, Yaqi Wang, Qinglong Liu, Shilong Pang, Dongfeng Zhao, Jiangbo Jiu
    2025, 78(2):  140-149.  doi:10.1016/j.cjche.2024.09.032
    Abstract ( 16 )   PDF (6692KB) ( 20 )  
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    Emergency resources play a vital role in the emergency rescue process. The adequate and timely supply of emergency resources can effectively control the development of accidents and reduce accident losses. However, the current emergency resource allocation of chemical enterprises lacks scientific analysis of accident scenarios, and the individual allocation method of enterprises increases the cost of emergency resource allocation. Given the above problems, this paper proposes a regional collaborative allocation method of emergency resources for enterprises within the chemical industry park (CIP) based on the worst credible accident scenario (WCAS). Firstly, the concept and analysis method of the WCAS is proposed. Then, based on the characteristics and consequences of the accident, the mapping relationship between accident scenarios and emergency resources is established. Finally, an optimization model for regional collaborative allocation of emergency resources is constructed to determine the amount of emergency resource allocation for each enterprise. Through the case study, the emergency resource allocation method based on the WCAS analysis can better meet the demands of accident emergency rescue. Simultaneously, the regional collaborative allocation optimization model can strengthen the cooperation ability among enterprises, greatly reducing the cost of emergency resource allocation for each enterprise.
    Heteropolyacid hosted to nano-silica catalyst for the oxidation of methacrolein
    Gang Hu, Qinqin Wang, Mingyuan Zhu, Lihua Kang
    2025, 78(2):  150-162.  doi:10.1016/j.cjche.2024.10.027
    Abstract ( 17 )   PDF (18610KB) ( 45 )  
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    In this study, a catalyst was synthesized using a two-step in-situ molecular beam epitaxy method to grow H4PMo11VO40 (HPAV) on amination-treated SiO2 nanoparticles, which served as both dopant and host agents. SiO2 dopant was modified with (3-aminopropyl)triethoxysilane (APTS), facilitating the formation of ammonium ions that enhanced the overall positive charge. This modification enabled the effective dispersion and exposure of HPAV's active species and induced a structural transformation of HPAV from a triclinic to a cubic crystal phase. The two-step hosting growth process optimized the proportions of Cs+, H+ and NH4+ antinuclear ions, thereby fine-tuning the synergistic catalysis of oxidation and acidity, as well as the oxidative sensitivity at HPAV catalytic interface. The resultant 8(HPAV)&4(Cs3PAV)-NH2-SiO2 catalyst achieved a methacrolein (MAL) conversion rate of 84% and a methacrylic acid (MAA) selectivity of 71%. Even after 10.5 h of reaction time, the catalyst retained its high dispersion, cubic crystal structure, and Keggin configuration, demonstrating stable catalytic performance over a continuous 200-h reaction period.
    Physically-consistent-WGAN based small sample fault diagnosis for industrial processes
    Siyu Tang, Hongbo Shi, Bing Song, Yang Tao, Shuai Tan
    2025, 78(2):  163-174.  doi:10.1016/j.cjche.2024.10.028
    Abstract ( 13 )   PDF (8810KB) ( 11 )  
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    In real industrial scenarios, equipment cannot be operated in a faulty state for a long time, resulting in a very limited number of available fault samples, and the method of data augmentation using generative adversarial networks for smallsample data has achieved a wide range of applications. However, the current generative adversarial networks applied in industrial processes do not impose realistic physical constraints on the generation of data, resulting in the generation of data that do not have realistic physical consistency. To address this problem, this paper proposes a physical consistency-based WGAN, designs a loss function containing physical constraints for industrial processes, and validates the effectiveness of the method using a common dataset in the field of industrial process fault diagnosis. The experimental results show that the proposed method not only makes the generated data consistent with the physical constraints of the industrial process, but also has better fault diagnosis performance than the existing GAN-based methods.
    Gold nanoparticles on Fe-doped Co3O4 for enhanced low-temperature CO oxidation
    Jianfang Liu, Hongwei Huang, Jie Yang, Laishuan Liu, Yu Li
    2025, 78(2):  175-186.  doi:10.1016/j.cjche.2024.10.015
    Abstract ( 13 )   PDF (14407KB) ( 7 )  
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    A series of Au/CoxFe3-xO4 catalysts was synthesized using the sol-deposition method by depositing 2–5 nm Au particles on Fe-doped Co3O4. Co2FeO4, with a Co/Fe molar ratio of 2:1, exhibited higher specific surface area, Co3+/Co2+ ratio, and oxygen vacancy content compared to Co3O4. As a result, it displayed better performance in CO oxidation, achieving a total conversion temperature (T100) of 96 ℃. Au greatly improved the catalytic efficiency of all CoxFe3-xO4 samples, with the 0.2%Au/Co2FeO4 catalyst achieving a further decrease in T100 to 73 ℃. Stability tests conducted at room temperature on the 1%Au/CoxFe3-xO4 catalysts demonstrated a slowed deactivation rate after Fe-doping. The reaction pathway for CO oxidation catalyzed by Au/Co2FeO4 followed the Mars-van Krevelen mechanism.
    Study on sulfur resistance of MnO2/Beta zeolite in toluene catalytic combustion: The effect of increased acidity on catalytic performance
    Zhuo Wang, Zetao Jin, Hanqi Ning, Baishun Jiang, Kaiyuan Xie, Shufeng Zuo, Qiuyan Wang
    2025, 78(2):  187-195.  doi:10.1016/j.cjche.2024.10.023
    Abstract ( 14 )   PDF (11611KB) ( 1 )  
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    Sulfur dioxide (SO2) frequently coexist with volatile organic compounds (VOCs) in exhaust gas. The competitive adsorption of SO2 and VOCs can adversely affect the efficiency of catalytic combustion, leading to catalyst poisoning and irreversible loss of activity. To investigate the impact of sulfur poisoning on the catalysts, we prepared the MnO2/Beta zeolite, and a corresponding series of sulfur-poisoned catalysts through in-situ thermal decomposition of (NH4)2SO4. The decrease in toluene catalytic activity of poisoned MnO2/Beta zeolite primarily results from the conversion of the active species MnO2 to MnSO4. However, the crystal structure and the porous structure of MnO2/Beta zeolite were stable, and original structure was still maintained when 1.6% (mass) sulfur species were introduced. Furthermore, the extra-framework Al of Beta zeolite could capture sulfur species to generate Al2(SO4)3, thereby reducing sulfur species from reacting with Mn4+ active sites. The combination of sulfur and Beta zeolite was found to directly produce new strong-acid sites, thus effectively compensating for the effect of reduced Mn4+ active species on the catalytic activity.
    Effect of sodium zeolite mixed metal oxide catalysts on catalytic conversion of mixed-density plastic into carbon nanotubes and hydrogen fuel
    Farzin Sheikh, Hammad Hussain, Muhammad Yasin Naz, Bilal Shoukat, Yasin Khan, Muhammad Shoaib
    2025, 78(2):  196-204.  doi:10.1016/j.cjche.2024.09.030
    Abstract ( 13 )   PDF (7227KB) ( 3 )  
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    A combination of experimental and statistical analysis presents a comprehensive understanding of the microwave pyrolysis technique for catalytic deconstruction of mixed-density plastics. By optimizing the process parameters and catalyst selection, it is possible to maximize the production of valuable solid and energy products, contributing to sustainable waste management. In this work, different mixed-density plastics were pyrolyzed with different catalysts and residence times to yield liquid fuel, syngas, and structured carbon residue. The effect of inputs on the product type, yield and composition was statistically evaluated using ANOVA, which showed an F value of 4.108 and a p-value of 0.098 (>1.00). FTIR and GC-MS revealed that the oil product consisted of C13+ fractions in the form of alkanes, alkenes, and aromatics. The microscopic analysis of the residue confirmed the formation of carbon nanotubes along with other amorphous products. The presence of impurities in the solid product was further analyzed through XRD analysis. The pyrolytic liquid fuel revealed the presence of conjugated aromatic structure and carbonyl group in their concentration. This research demonstrated that converting mixed-density plastics using sodium zeolite, aluminum oxide, and nickel oxide catalysts yields 84% valuable products, confirming wasted plastics as a lucrative energy feedstock for producing hydrogen and high-value carbon compounds.
    CFD investigation in the temperature effect on coal catalytic hydrogasification in the pressurized bubbling fluidized bed
    Yin Zhang, Shuai Yan, Zihong Xia, Caixia Chen, Xuan Qu, Jicheng Bi
    2025, 78(2):  205-217.  doi:10.1016/j.cjche.2024.10.020
    Abstract ( 14 )   PDF (11740KB) ( 6 )  
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    Temperature is a critical factor influencing the performance of coal catalytic hydrogasification in bubbling fluidized bed gasifiers. Numerical simulations at various temperatures (1023 K, 1073 K, 1123 K, and 1173 K) are conducted to elucidate the mechanisms by which temperature affects bubble size, global reaction performance, and particle-scale reactivity. The simulation results indicate that bubble size increases at elevated temperatures, while H2-char hydrogasification reactivity is enhanced. Particle trajectory analyses reveal that particles sized between 100 and 250 μm undergo intense char hydrogasification in the dense phase, contributing to the formation of hot spots. To assess the impact of temperature on the particle-scale flow-transfer-reaction process, the dimensionless quantities of Reynolds, Nusselt, and Sherwood numbers, along with the solids dispersion coefficient, are calculated. It is found that higher temperatures inhibit bubble-induced mass and heat transfer. In general, 3 MPa, 1123 K, and 3–4 fluidization numbers are identified as the optimal conditions for particles ranging from 0 to 350 μm. These findings provide valuable insights into the inherent interactions between temperature and gas-particle reaction.
    Numerical simulation of power and flow field characteristics of different spiral stirred reactors
    Qingzhao Liu, Yang Qin, Guodong Zhu, Xubin Zhang, Fumin Wang, Guobing Li, Shuai Liu, Zhiwei Zhang, Bingxin Zhu, Zheng Wang
    2025, 78(2):  218-231.  doi:10.1016/j.cjche.2024.10.021
    Abstract ( 14 )   PDF (26415KB) ( 2 )  
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    Under the dual-carbon background, the technological updating of traditional high-energy-consuming equipment should not be delayed, and the problem of reactor energy consumption should not be ignored. Therefore, this study is based on computational fluid dynamics (CFD) theory to simulate the spiral stirred reactor with different design parameters (distance of paddle from bottom surface to reactor height ratio h1/H, diameter of stirring paddle to reactor diameter ratio Ds/D, length of blade section to reactor height ratio Ls/H). It was found that the reactor designed with lower Ls/H values and higher h1/H, Ds/D values would have smaller power number (Np) values and smaller flow field average velocity. In addition, this study also fitted the correlation equation of Np concerning Reynolds number and h1/H, Ds/D, and Ls/H, and the conclusions of the study can be used as a reference for the design of industrial equipment.
    Kinetics of hydrogen sulfide removal from coke oven gas over faujasite zeolite: Experimental and modeling studies
    Feng Gao, Sixiao Zhu, Liping Chang, Weiren Bao, Jinghong Ma, Junjie Liao
    2025, 78(2):  232-244.  doi:10.1016/j.cjche.2024.10.022
    Abstract ( 15 )   PDF (10253KB) ( 4 )  
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    The removal of H2S from coke oven gas (COG) is an important issue for the further utilization of COG. Zeolites could be used for industrial desulfurization owing to their high thermal stability and regenerability. However, further analysis on the kinetics of deep desulfurization using zeolites is necessary to provide relevant information for industrial design. In this study, the desulfurization breakthrough curves of faujasite (FAU) zeolite in COG were measured using a fixed bed reactor. The adsorption isotherm was investigated using the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich models. The adsorption saturated capacity of H2S was inversely related to the temperature. The results show that the Langmuir model best fits the adsorption isotherm with a lower value of root-mean-square-error (RMSE) and Chi-Square (χ2), and the calculated activation energy is 14.62 kJ·mol-1. The adsorption kinetics were investigated using pseudo-first-order (PFO), pseudo-second-order (PSO), Bangham and Weber-Morris models. The Bangham model fitted the kinetic data well, indicating that pore diffusion is an influential factor in the adsorption process. The Weber-Morris model suggests that the adsorption rate was not solely determined by the pore diffusion, but was also influenced by the active site on the FAU zeolite. The adsorption breakthrough curves under different gas flow rates were fitted using the bed depth service time (BDST) model, and it provides an accurate prediction of the breakthrough time with a small relative error. The results of thermodynamic analysis demonstrated the feasibility and spontaneity (ΔG<0) and exothermic (ΔH<0) nature of the adsorption process of the FAU zeolite for H2S under COG.
    Distributed asynchronous double accelerated optimization for ethylene plant considering delays
    Ting Wang, Zhongmei Li, Wenli Du
    2025, 78(2):  245-250.  doi:10.1016/j.cjche.2024.11.003
    Abstract ( 14 )   PDF (6200KB) ( 52 )  
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    Considering the complexity of plant-wide optimization for large-scale industries, a distributed optimization framework to solve the profit optimization problem in ethylene whole process is proposed. To tackle the delays arising from the residence time for materials passing through production units during the process with guaranteed constraint satisfaction, an asynchronous distributed parameter projection algorithm with gradient tracking method is introduced. Besides, the heavy ball momentum and Nesterov momentum are incorporated into the proposed algorithm in order to achieve double acceleration properties. The experimental results show that the proposed asynchronous algorithm can achieve a faster convergence compared with the synchronous algorithm.
    Structural evolution of iron components and their action behavior on lignite combustion
    Jialin Chen, Zhenghao Yan, Runxia He, Yanpeng Ban, Huacong Zhou, Quansheng Liu
    2025, 78(2):  251-262.  doi:10.1016/j.cjche.2024.10.012
    Abstract ( 13 )   PDF (11980KB) ( 2 )  
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    Spontaneous combustion of lignite is closely related to the inherent minerals it contains, and the iron component has a remarkable influence on the combustion property of lignite. It is very important to study the influence of iron component on the combustion reaction property of lignite to reveal autoignition mechanism of lignite and reduce autoignition of lignite. In this research, FeCl3 and Fe2O3 were doped into demineralised lignite (SL+) by impregnation to research the effects of iron salts and iron oxides on the combustion properties of lignite. Based on the above, the effects of post-treatment method of the FeCl3-doped coal samples, iron-salt hydrolysis products and heat-treated temperatures on the combustion property of lignite were researched, and the microstructures of the coal samples were characterised and analysed using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that doping with FeCl3 increases the combustion performance of lignite, thereby reducing the ignition temperature of lignite by approximately 112 ℃. In contrast, doping with Fe2O3 has a weaker combustion-promoting effect. XRD and XPS characterisation indicates that iron species in the coal samples doped with iron salts are highly dispersed and exhibit the FeOOH structure, whereas iron species in the coal samples doped with Fe2O3 exhibit the crystal form of α-Fe2O3. Doping of lignite with FeCl3 and its hydrolysis product β-FeOOH reduces the ignition temperature of the coal samples. Iron species in the FeCl3-doped coal samples after heat treatment at 300–500 ℃ increase the combustion property of the coal samples, whereas iron species after heat treatment at 600–900 ℃ have a much weaker or non-existent promoting effect on the combustion performance of the coal samples. The characterisation show a change in iron species in the coal samples with the rise in the heat treatment temperature. This change progresses from highly dispersed β-FeOOH below 300 ℃ to Fe3O4 above 400 ℃. Fe3O4 is gradually reduced, with part of it further reduced to elementary iron at the same time as grain growth. It is believed that the gradual agglomeration of Fe3O4 and the appearance of elementary iron are the main reasons for the weakening or disappearance of the promoting effect on coal combustion.
    3-Acetamido-5-acetylfuran: An emerging renewable nitrogen-containing platform compound
    Jinhang Dai, Qingya Cao, Delong Yang, Gang Chen, Ziting Du, Song Wang, Fukun Li
    2025, 78(2):  263-272.  doi:10.1016/j.cjche.2024.10.029
    Abstract ( 9 )   PDF (7127KB) ( 3 )  
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    In the last decade, shell biorefinery, a novel concept referring to the extraction of the main components of crustacean shells and the transformation of each component into valuable products, was proposed and has attracted increasing attentions. Chitin is one of main components of crustacean shells. Owing to the bio-fixed nitrogen element, chitin biomass has been regarded as a good candidate to produce nitrogen-containing chemicals. Among these, 3-acetamido-5-acetylfuran (3A5AF) is an interesting furanic compound derived from the hydrolysis and sequential dehydration of chitin. Similar to cellulose-derived platform chemical 5-hydromethylfurfural (HMF), 3A5AF is an emerging platform compound and also can be converted into various useful chemicals by oxidation, reduction, hydrolysis, substitution, and so on. This review showcases the recent advances in the synthesis of 3A5AF from chitin and N-acetyl glucosamine (NAG) employing various catalytic systems. The conversion of 3A5AF into valuable compounds was introduced then. There are still some challenges in this area, for example, the rational design of green and efficient catalytic systems for the synthesis of 3A5AF and its derivatives. The outlooks also were discussed at the end of the review.
    Study on the recovery of NMP waste liquid in lithium battery production by coupled pervaporation–adsorption process and evaluation of technical and economic performances
    Jiayi Zhang, Jiali He, Guibing Wang, Yu Zhao, Huairong Zhou, Dongliang Wang, Dongqiang Zhang
    2025, 78(2):  273-283.  doi:10.1016/j.cjche.2024.10.006
    Abstract ( 15 )   PDF (10682KB) ( 9 )  
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    N-methyl-pyrrolidone (NMP) is an important solvent for the production of lithium batteries, which causes environmental pollution and wastes resources if it is directly discharged. The current commonly used vacuum distillation recovery process suffers from high operating costs and high energy consumption. Therefore, this paper proposes a coupled pervaporation-adsorption (PV-A) process to recover NMP solvents from lithium battery production waste streams. In this process, pervaporation is used to dewater the NMP waste liquid, it was found that the water content in the raw material liquid decreased from the initial 8.3% (mass) to 0.14% (mass) after 400 min of dewatering, but the membrane separation performance decreased significantly when the water content of the raw material liquid decreased to 0.45% (mass), and at the same time, the NMP loss rate increased rapidly. An adsorption process was used to remove trace water from the remaining liquid, and the water content in the feed liquid under the optimal adsorption process conditions was reduced from 0.45% (mass) to 0.014%, which fully meets the purity requirements of electronics-grade NMP for the production of lithium batteries. Steady-state modeling and techno-economic evaluation of the proposed coupled process were carried out, and compared with vacuum distillation and pervaporation technologies, the results showed the PV-A process yielded the best techno-economic performance and the lowest environmental impact, and it can be used as an alternative process to the traditional NMP recycling technology. This study provides a new method for the recycling of NMP in the lithium battery industry.
    Hybrid model of multimodal based on data enhancement and lumped reaction kinetics: Applying to industrial ebullated-bed residue hydrogenation unit
    Jian Long, Mengru Zhang, Anlan Li, Cheng Huang, Dong Xue
    2025, 78(2):  284-302.  doi:10.1016/j.cjche.2024.10.019
    Abstract ( 14 )   PDF (17812KB) ( 57 )  
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    Industrial ebullated-bed is an important device for promoting the cleaning and upgrading of oil products. The lumped kinetic model is a powerful tool for predicting the product yield of the ebullated-bed residue hydrogenation (EBRH) unit, However, during the long-term operation of the device, there are phenomena such as low frequency of material property analysis leading to limited operating data and diverse operating modes at the same time scale, which poses a huge challenge to building an accurate product yield prediction model. To address these challenges, a data augmentation-based eleven lumped reaction kinetics mechanism model was constructed. This model combines generative adversarial networks, outlier elimination, and L2 norm data filtering to expand the dataset and utilizes kernel principal component analysis-fuzzy C-means for operating condition partitioning. Based on the hydrogenation reaction mechanism, a single and sub operating condition eleven lumped reaction kinetics model of an ebullated-bed residue hydrogenation unit, comprising 55 reaction paths and 110 parameters, was constructed before and after data augmentation. Compared to the single model before data enhancement, the average absolute error of the sub-models under data enhancement division was reduced by 23%. Thus, these findings can help guide the operation and optimization of the production process.
    Thermal coupling study during the co-processing of coal and biomass in the lab-scale adiabatic reactor
    Laisong Wang, Zhidi Du, Jie Feng, Xiaolong Shi, Wenying Li
    2025, 78(2):  303-313.  doi:10.1016/j.cjche.2024.10.018
    Abstract ( 17 )   PDF (9322KB) ( 2 )  
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    A lab-scale adiabatic reactor has been self-made to characterize the coupled properties of heat and reactions during the co-thermal-processing of coal and biomass with steam or steam/O2 gasification agents. Results showed that the synergistic effects caused by heat transfer between corncob and coal at different mixing ratios were heavily determined by coal rank and gasification agent. During steam co-processing, the heat transfer from corncob char to adjacent bituminous coal char promoted the water-gas reaction on coal char and contributed to synergistic effects; the heat transfer from anthracite char to adjacent corncob char reduced the kinetic rate of the water-gas reaction on coal char and contributed to inhibitory effects, and the inhibitory effect caused by heat transfer was greater than the promotion effects of biomass mass transfer. The introduction of O2 diminished the impact of inter-particle heat transfer and altered the intensity of synergy, decreasing the values of synergy factor of bituminous coal/corncob blends by 17% and increasing the value of synergy factor of anthracite/corncob blends by 142.5%. This study provides sufficient support for the process conditions selection for the production of syngas with specific H2/CO molar ratios and the desired level of gasification performance.
    Fluorosurfactants and their application in droplet microreactors: An overview
    Wei Cheng, Huilin Wen, Xiaoqiang Chen, Shaobin Zhang, Ziyi Yu
    2025, 78(2):  314-326.  doi:10.1016/j.cjche.2024.11.001
    Abstract ( 16 )   PDF (14282KB) ( 9 )  
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    Fluorosurfactants play a crucial role in ensuring the stability and uniformity of droplet microreactors, which significantly broaden their applications in chemical and biological research. This review covers structure diversity and functional versatility of fluorosurfactants. Fluorosurfactants can be divided into two basic types according to their structure, linear and dendritic types, which both provides individual advantages. Linear fluorosurfactants are easily synthesized and commercially available, whereas dendritic fluorosurfactants have a branched structure that greatly reduces molecular cross-talk between droplets. Based on the application point of view, fluorosurfactants can be further classified into two categories: reactive and responsive fluorosurfactants. The hydrophilic head of reactive fluorosurfactants contains a reactive functional group, making them very useful in other applications, such as microcapsule preparation or protein crystallization. In contrast, responsive fluorosurfactants would change their properties with respect to external stimuli, such as temperature or light, making them perfect candidates for the on-demand control of droplet behavior. Development of these new classes of fluorosurfactants has expanded the capabilities and applications of droplet microreactors that enables interdisciplinary challenges to be solved.