Journal of Chemical Engineering of Chinese Universities

 

Current Issue

  • Research progress on condensation polymerization reactor with high viscosity fluids

    CHENG Wenkai<sup>1</sup>; YAN Jinyu<sup>1</sup>; WANG Jiajun<sup>2</sup>; FENG Lianfang<sup>2;3</sup>

    The highly efficient condensation polymerization reactor is the key to develop advanced polymerization process. This article reviews several types of highly viscous condensation polymerization reactor, including horizontal single-shaft reactors, horizontal twin-shaft reactors, vertical falling film reactors and vertical combined reactors. Research progress on equipment characteristics and application of condensation polymerization reactors was also reported. It is pointed out that the film formation and surface renewal performance are key factors to enhance mass transfer process. Computational fluid dynamics (CFD) simulation is the main method for studying equipment characteristics. Effective combination of different film forming elements can be used to develop novel reactors. Combination of reactors with different performance can be used to prepare polymers with high performance and high molecular weight, optimize polymerization processes, and to develop advanced polymerization processes. The study can provide ideas for the development of highly efficient condensation polymerization reactor.

    2025 05 [Abstract][OnlineView][Download 11852K]

  • Research progress in NAD(P)H regeneration in continuous flow biocatalysis

    HE Changan<sup>1</sup>; DUAN Jindian<sup>1</sup>; WANG Zhixiang<sup>2</sup>; ZHANG Quan<sup>3</sup>; YANG Zhao<sup>2</sup>; HU Yujing<sup>1</sup>

    Continuous flow chemistry, a transformative technology enabling chemical reactions in continuous flow systems, has gained significant importance in pharmaceuticals, chemical engineering, energy, and materials science. The integration of enzymatic catalysis, particularly valued for its exceptional enantioselectivity, has demonstrated remarkable advantages for pharmaceutical synthesis in flow systems. However, achieving efficient and cost-effective regeneration of oxidoreductase cofactors NAD(P)<sup>+</sup> remains a critical scientific challenge. This review comprehensively summarizes recent advances in cofactor recycling strategies within continuous flow biocatalytic systems, critically examines key limitations in current cofactor regeneration approaches, and proposes future research directions to accelerate the industrial applications of flow-based biocatalysis.

    2025 05 [Abstract][OnlineView][Download 7784K]

  • Progress in the influence of promoters on the performances of the Fe-based Fischer-Tropsch synthesis catalysts

    CHEN Chao; SUO Xiaoming; LI Zhengjia; CEN Jie; YAO Nan

    Fischer-Tropsch synthesis (FTS) technology has great significance for achieving the "dual carbon" target and ensuring national energy security. Fe-based catalysts is an important part of FTS technology, whose reaction performances are affected by various types of promoters. This paper firstly reviewed the mechanisms and influences of different types of promoters used for Fe-based catalysts. On this basis, the mechanism of CO<sub>2</sub> generation in Fe-based catalyst involved FTS process and the research progress of Fe-based catalysts with low CO<sub>2</sub> selectivities were summarized. This paper also prospected the future research of Fe-based FTS catalysts to provide some new ideas and methods for the preparation of Fe-based FTS catalysts with higher reactivities, stabilities and low CO<sub>2</sub> selectivities.

    2025 05 [Abstract][OnlineView][Download 2129K]

  • Progress on the synthesis of 2,3,3,3-tetrafluoropropene and the catalysts

    WAN Li<sup>1</sup>; LIU Minyang<sup>2</sup>; YU Wanjin<sup>2</sup>; CHENG Dangguo<sup>1</sup>; CHEN Fengqiu<sup>1</sup>

    2,3,3,3-tetrafluoropropene (HFO-1234yf) offers the advantages of zero ozone depletion potential (ODP) and low global warming potential (GWP). Its thermophysical properties closely resemble those of the third-generation refrigerant 1,1,1,2-Tetrafluoroethane (HFC-134a), enabling HFO-1234yf to serve as a direct replacement for HFC-134a in existing automotive air conditioning systems without necessitating any design modifications. HFO-1234yf has become one of the most promising candidates among fourth-generation heat transfer fluids. This paper provides a comprehensive review of the current synthesis routes for HFO-1234yf, comparing the advantages and limitations of each approach. It proposes that the synthesis of HFO-1234yf from C<sub>2</sub> feedstocks, such as 2-chloro-1,1-difluoroethylene, or from C<sub>3</sub> feedstocks, such as 1,1,1,2,2,3-hexachloropropane and 3,3,3-trifluoropropene, offers several benefits, including high yields, the ready availability of raw materials, and mild reaction conditions, which collectively enhance the process’s value for industrial applications. The catalysts employed in key reactions such as telomerization, hydrogenation, fluorination, and dehydrohalogenation within the synthesis routes of HFO-1234yf are also summarized. Finally, the paper emphasizes future research directions, suggesting that priorities should focus on developing new, green, and efficient synthesis routes. Additionally, it advocates for the design of long lifetime telomerization catalysts that offer high conversion rates and selectivity, ease of regeneration, and the development of highly active, durable, and carbon-resistant non-chromium-based catalysts to replace environmentally harmful chromium-based catalysts.

    2025 05 [Abstract][OnlineView][Download 4201K]

  • Saturation properties of HFO refrigerants by PC-SAFT equation of state

    CHEN Zhiqiang; YIN Jianguo; ZHAO Guanjia; MA Suxia

    The well-known molecular based Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state, which is parametrized by the fitting of experimental saturated vapor pressure and saturated liquid density data, are expected to predict the saturated vapor density with low accuracy. In this study, the experimental data of saturated vapor density, as well as the vapor pressure and saturated liquid density data, were included in the parametrization method to meet the ultimate objective and various parameter models were also investigated. Four representative hydrofluoroolefin (HFO) refrigerants, i.e., R1234yf、R1234ze(E)、R1234ze(Z) and R1243zf, were used to verify the performance of the new parametrization method and the temperature-dependent parameter models. The results revealed that higher accuracy could be obtained not only for saturated vapor density but also for all the saturated properties, though lower accuracy for vapor pressure were observed, when saturated vapor density data were added in the parametrization process. Higher accuracy for vapor pressure couldbe obtained with the exponential temperature-dependent parameter model when using the new parametrization method. The maximum and minimum average AARDs of the three saturated properties for four HFOs are 0.75%and 0.48%, respectively. The conclusions contribute to the development and improvement of the SAFT type equation of state.

    2025 05 [Abstract][OnlineView][Download 1661K]

  • Dynamic behaviors of high-viscosity droplets with low surface tension impacting on rough surfaces

    Jianfei<sup>1;2</sup>; DING Xu<sup>1;2</sup>; LIU Ji<sup>1;2</sup>; WEI Fangrong<sup>1;2</sup>

    The dynamic behavior of heavy oil droplets impacting surfaces is a pivotal issue in understanding the carbonaceous deposition process on the outer surface of the vortex finder in catalytic cracking cyclone separators. To minimize the effects of carbonaceous deposition on the wall of the vortex finder due to the impact of heavy oil droplets, in this study, we focused on glycerol-ethanol solutions, which exhibit similar physical properties to heavy oil droplets(high viscosity and low surface tension)at high temperatures. By integrating high-speed imaging technology with numerical simulations, we investigated the wall-impact behavior of these droplets. Consequently, we developed a mathematical model to predict the outcomes of droplet collisions with wall surfaces. The results indicated that surface characteristics and droplet properties had a minor effect on the initial stage of the droplet impact process. As the impact process progresses, the droplet spreading coefficient decreases with increasing surface roughness. The contact angle formed between a high viscosity and low surface tension droplets and a surface with excellent wettability is smaller, indicating that the droplet exhibits stronger spreading performance and tends to adhere closely to the surface. The oil hydrophobic property of the surface can be improved by appropriately reducing the cantilever length of the surface microstructure. By introducing dimensionless parameters, a predictive model for the critical condition of droplet splashing on rough and dry surfaces <i>We</i><sub>c</sub>=667.12·<i>Oh</i>(<i>R</i><sub>a</sub>/<i>D</i><sub>0</sub>)<sup>-0.75</sup> is established . This model can effectively predict the splashing behavior of high-viscosity, low-surface-tension droplets on rough and dry surfaces. The research results provide a theoretical reference for analyzing the interaction mechanism between heavy oil droplets and wall surfaces.

    2025 05 [Abstract][OnlineView][Download 8105K]

  • Study on critical fluidization characteristics of Geldart-B mixed particles with isodensity

    WANG Hongfei<sup>1;2</sup>; LIU Hantao<sup>1</sup>; BA Zhongren<sup>2</sup>; ZHAO Jiantao<sup>2</sup>; FANG Yitian<sup>2</sup>

    In order to understand the transitional fluidization of mixed particles in gas-solid fluidized bed, the critical fluidization characteristics of Geldart B-type binary, ternary, and wide-size distribution mixed particles were investigated by cold-mode experiments. We examined the effect of particle composition, particle size ratio, and particle size distribution on the critical characteristic velocities and the bed voidage was examined. A phase diagram of the separation-mixing fluidization equilibrium of mixed particles was established. The results showed that the change in bed voidage caused by particle composition and size ratio is the essential reason for the difference of the critical fluidization characteristics. As the increase of the mass fraction of coarse particles, the bed voidage first decreases and then increases. As the increase of the particle size ratio, the bed voidage decreases. When the mass fraction of the coarse particles was greater than 0.4, the critical characteristic velocities increase significantly. The addition of the medium particles attenuates the segregation behavior of the mixed particles, and the fluidization process has no obvious stratified phase boundary. The prediction models for the critical characteristic velocities of transitional fluidization were established by considering the effects of the particle composition and the size ratio on the bed voidage, which provided the theoretical foundation for determining the transitional fluidization of mixed particles.

    2025 05 [Abstract][OnlineView][Download 1700K]

  • Numerical study of energy conversion process in cold mold system of flue gas turbine

    GUO Ying<sup>2</sup>; WAN Dehai<sup>1</sup>; WANG Jianjun<sup>1</sup>; CHANG Yuanjiang<sup>2</sup>; WANG Qi<sup>1</sup>

    In refineries, flue gas turbines are utilized to recover energy from the regenerated flue gas in catalytic cracking units, serving as crucial energy-saving equipment. Previous research on flue gas turbines often employed numerical simulation methods such as sliding mesh techniques, which impose an active rotational speed on the rotor. However, these methods deviate from the actual physical working process of flue gas turbines. Therefore, this study adopts a six-degree-of-freedom (6-DOF) approach to numerically simulate the flow field during both the energy conversion and energy output processes of the flue gas turbine. A corresponding cold model experimental system was established, and PIV flow field testing was conducted. The accuracy of the numerical simulation was verified based on both flow and power parameters. The results indicate that, compared to traditional methods like sliding mesh that impose a fixed rotational speed on the rotor, the 6-DOF method can solve the flow field during the energy conversion process of the flue gas turbine, more closely aligning with the actual physical working process of the turbine. On this basis, the full flow field during the energy conversion process of the cold model system was obtained, and the energy conversion efficiency among various components of the energy recovery system was evaluated based on the power parameters derived from the numerical simulation. The findings of this study provide a new approach for fundamental research on the internal flow field of energy recovery systems in catalytic cracking flue gas turbines.

    2025 05 [Abstract][OnlineView][Download 13098K]

  • Process study on catalytic dehydration of fructose to 5-HMFover ZSM-5 zeolite in isopropanol

    REN Aotian<sup>1</sup>; XU Ling<sup>3</sup>; QIN Wenqi<sup>1</sup>; NIE Renfeng<sup>2</sup>; LYU Xiuyang<sup>1</sup>

    5-Hydroxymethylfurfural (5-HMF) is one of the biomass-based platform compounds. To address the challenges in homogeneous catalysis for 5-HMF production, such as catalyst separation, high material consumption, and severe pollution, the production of 5-HMF from fructose via solid acid catalysis in the green solvent isopropanol was investigated in this study. Based on the screening of solid acid catalysts, the process, kinetics, and catalyst reuse were explored. It was found that nanoscale ZSM-5 zeolite with a silica-alumina ratio of 25 is an optimal catalyst for the dehydration of fructose to 5-HMF in isopropanol. The optimized process conditions were established as follows: 0.04 g of fructose, 0.02 g of ZSM-5, 4 mL of isopropanol, stirring at 500 rpm, and a reaction time of 4 hours at 150 ℃, yielding 59.1%of 5-HMF. Based on kinetic studies, the apparent activation energy for the dehydration of fructose to 5-HMF in isopropanol was found to be 61.74 kJ·mol<sup>-1</sup>. While catalyst reuse experiments show a decrease in conversion, the selectivity remains largely unchanged. The crystal structure of the ZSM-5 catalyst was revealed to remain unchanged before and after use by characterization techniques including BET, XRD, and NH<sub>3</sub>-TPD, though the microporosity and acidity decrease, possibly due to the generation of humus that covered some acidic sites on the catalyst surface or partial blockage of the pores. This research provides new insights for the green and efficient production of 5-HMF.

    2025 05 [Abstract][OnlineView][Download 1134K]

  • Fault tracing of industrial process based on causal reasoning of transfer entropy network based on BDGL-CMI

    Shujuan<sup>1;2;3;5</sup>; QI Yongsheng<sup>1;2;3</sup>; LIU Liqiang<sup>1;2;3</sup>; LI Yongting<sup>1;2;3</sup>; GAO Xuejin<sup>4</sup>

    To address the problems of long tracing times and poor fault tracing results caused by the interrelated effects of multiple factors in complex industrial processes, we proposed a fault tracing algorithm that integrates the block drop form of the graphical lasso (BDGL) with transfer entropy and conditional mutual information(CMI). First, we introduced an optimized graph lasso to model subgroups, effectively reducing computational complexity. Then, we applied transfer entropy for causal analysis to obtain the main variable pairs of transfer entropy. By calculating conditional mutual information, we analyzed the direct and indirect causal relationships of the prominent variables. Finally, based on the tracing process, we determined a concise industrial process fault tracing graph and analyze the root cause of the fault, enabling process recovery. Using data from a chilled water system and the Tennessee Eastman industrial process, we conducted causal analysis for fault tracing, verifying the effectiveness and practicality of this tracing method. This method not only improves the efficiency of fault tracing but also enhances the accuracy and interpretability of the results.

    2025 05 [Abstract][OnlineView][Download 5098K]

  • Synthesis, structure and properties of silane crosslinked water-borne polyacrylate pressure-sensitive adhesives

    YAN Keqin<sup>1</sup>; YU Dayang<sup>2</sup>; BAO Yongzhong<sup>1;2</sup>

    To endure repeated folding without the adhesion failure, yielding and fracture, polyacrylate pressure-sensitive adhesives (PSAs) used in flexible displays should possess superior adhesion characteristics along with favorable relaxation and recovery properties. In this study, water-borne polyacrylate PSAs with different mass fractions of methacryloxypropyl trimethoxylsilane (MPS) were prepared via semi-continuous emulsion polymerization, and effects of the mass fraction of MPS on the molecular structure, viscoelastic and mechanical properties of polyacrylate PSAs were investigated. It was found that silane crosslinking could be proceeded in the polymerization and the film forming process. The gel content of PSA was increased, and average molecular weights of sol and gel between crosslinking sites were decreased as the mass fraction of MPS increased. PSA with MPS mass fraction of 0.2%exhibited optimal comprehensive performances: a strain recovery rate of 83%under significant deformations, a stress relaxation rate of 72%, a peel strength of 8.9 N·(25 mm)<sup>-1</sup> against polished steel surfaces, excellent transmittance coupled with low haze, thereby fully complying with the stringent optical display requirements. The work provides an environmentally benign and efficient process route to synthesize PSAs for flexible display applications.

    2025 05 [Abstract][OnlineView][Download 1186K]

  • Preparation and characterization of sulfonated polyimide/sulfonated mesoporous silica proton exchange membranes

    CHENG Cheng<sup>1</sup>; ZHANG Qi<sup>1</sup>; ZHANG Zhengdong<sup>1</sup>; ZHONG Jing<sup>1</sup>; ZHOU Shouyong<sup>2</sup>

    In order to improve the hydrolysis stability and proton conductivity of sulfonated polyimide membrane, the sulfonated polyimide (SPI) with ether bonds and sulfonated mesoporous silica (SMCM) were blended. The SPI/SMCM proton exchange composite membranes were prepared by solution casting method. The effects of different SMCM contents on the microstructure and performance of SPI/SMCM composite membranes were investigated. The experimental results showed that the introduction of SMCM improved the thermal stability of the composite membranes. The large specific surface area of hydrophilic SMCM helped to improve the water uptake of SPI/SMCM composite membranes. The water uptake of SPI/SMCM-10%composite membrane reached 19.5%. The SMCM formed a support structure within the composite membranes to inhibit the swelling of the SPI/SMCM composite membranes and improve the dimensional stability of the composite membrane. The SPI/SMCM-6%proton exchange composite membrane had the best overall performance by comparing the performance of SPI/SMCM composite membrane. The tensile strength of SPI/SMCM-6%composite membrane was 34.3 MPa, which was 2.88 times higher than that of Nafion212 membrane (11.9 MPa). The SPI/SMCM-6%composite membrane had good hydrolysis stability with the value greater than 360 h. The proton conductivity of SPI/SMCM-6%composite membrane in deionized water at 90 ℃ reached 0.286 S·cm<sup>-1</sup>. The introduction of hydrophilic SMCM formed a continuous proton transport channel in the SPI/SMCM composite membranes and improved the proton conductivity of the composite membranes.

    2025 05 [Abstract][OnlineView][Download 2649K]

  • Preparation of <i>α</i>-CaSO<sub>4</sub>·0.5H<sub>2</sub>O nanowhiskers by microwave-ultrasonic-assisted method for oil-water separation

    ZHANG Litao<sup>1;2</sup>; SU Yixin<sup>3</sup>; LI Ju<sup>1;2</sup>; LI Yun<sup>1;2</sup>; GUO Hongfei<sup>1;2</sup>; CAO Jilin<sup>1;2</sup>

    To achieve the high-value utilization of FGD gypsum, the microwave-ultrasonic technique was used to synthesize <i>α</i>-CaSO<sub>4</sub>·0.5H<sub>2</sub>O nanowhiskers from FGD gypsum in a glycerol-water system with MgCl<sub>2</sub> as a crystal modifier. The effects of reaction temperature and duration, power of ultrasonic, the volume ratio of glycerol to water, as well as the addition amount of MgCl<sub>2</sub> on the products were investigated,and the enhancement mechanism of the microwave-ultrasonic technique on the synthesis of <i>α</i>-CaSO<sub>4</sub>·0.5H<sub>2</sub>O nano whiskers was explored. The obtained <i>α</i>-CaSO<sub>4</sub>·0.5H<sub>2</sub>O nanowhiskers featured a diameter of ca. 200 nm and an aspect ratio of about 30. The microwave-ultrasonic could dissolve a large amount of FGD gypsum in a short period of time, resulting in generation of a large number of crystal nuclei and forming products with smaller size. Meanwhile, the dispersion effect of ultrasonic could avoid the directional gathering of <i>α</i>-CaSO<sub>4</sub>·0.5H<sub>2</sub>O nano whiskers along[100] direction. The synthesized <i>α</i>-CaSO<sub>4</sub>·0.5H<sub>2</sub>O nanowhiskers were used for oil-water separation, and the separation efficiency could reach 98%. The solid-phase product after oil-water separation could be re-synthesized into <i>α</i>-CaSO<sub>4</sub>·0.5H<sub>2</sub>O nanowhiskers for recycling.

    2025 05 [Abstract][OnlineView][Download 12225K]

  • Urushiol-based benzoxazine capable of catalyzing the ring-opening polymerization of phenol-4,4'-diaminodiphenylmethane-type benzoxazine and enhancing its toughness

    ZHU Yongfei; XIAO Jianrui; LI Peilin; LI Jiayi

    In order to decrease the ring-opening polymerization (ROP) temperature of common benzoxazine and improve the toughness of polybenzoxaine, urushiol and dodecylamine-based benzoxazine (U-D) containing phenol hydroxyl and long alkyl chain was prepared as a catalyst and toughening modifier. Differential scanning calorimetry and gelation time test showed that U-D possessed a lower ROP temperature with an initial and peak temperature of 117.53 and 191.17 ℃, respectively. Moreover, the ROP peak temperature of benzoxazine based on phenol and 4,4'-diaminodiphenylmethane (P-DDM) had an obviously decrease (about 20-30 ℃) with the addition of U-D. Thermogravimetric analysis, dynamic mechanical analysis, impact and flexural strength tests indicate that the introduction of U-D resulted in a significant improvement in the impact strength of the cured P-DDM from 3.55 KJ·m<sup>-2</sup> to 6.68 KJ·m<sup>-2</sup> and residual carbon at 800℃ from 38.56%to about 60%, meanwhile, its flexural strength was also enhanced. Therefore, U-D is a kind of excellent additive capable of catalyzing the ROP of benzoxazine and toughening polybenzoxazine, which exhibits a promising application prospect.

    2025 05 [Abstract][OnlineView][Download 12025K]

  • Investigation into the remediation process of oil-contaminated soil utilizing biochar- immobilized microbial consortium

    MAO Xingshun; YANG Fan; SHI Hongjie; WANG Hanzheng; ZHU Minglong; TAN Wensong; ZHANG Xu

    Petroleum-contaminated soil (PCS) poses a significant threat to both ecosystems and human health. While bioremediation presents a promising avenue for addressing this issue, its efficacy is constrained by the sluggish degradation rates, prolonged treatment timelines, and the environmental sensitivity of indigenous microbial populations. The present study introduces a novel approach utilizing biochar-immobilized microbial consortia to surmount these obstacles. The methodology involved the isolation of hydrocarbon-degrading bacterial strains from PCS, the creation of an optimized microbial consortia via a "bottom-up" assembly approach, and the application of biochar immobilization to enhance microbial resilience. The biochar-immobilized microbial consortia achieved the degradation of 82.3% of saturated hydrocarbons and 71.9% of aromatic hydrocarbons. Kinetic analysis employing first-order kinetics demonstrated a reaction rate constant (k) of -0.037 5 s<sup>-1</sup>, a pollutant half-life of 18 d, and an 88% reduction in contaminant levels within 42 d—exceeding the performance of control samples. Microbial community analysis indicated that biochar not only stabilized the introduced strains but also stimulated the activity of native microorganisms, facilitating a synergistic degradation process and expediting remediation efforts. This innovative strategy, which combines engineered microbial consortia with the immobilization properties of biochar, overcomes traditional inefficiencies and presents a scalable industrial solution. The results underscore biochar’s dual functionality in stabilizing microbial activity and promoting the engagement of native microbial communities, thereby advancing methodologies for addressing complex contaminations. This research bridges the gap between laboratory innovation and practical application, establishing a framework for effective, large-scale PCS remediation.

    2025 05 [Abstract][OnlineView][Download 9301K]

  • Fabrication of Sn doped Ti/RuO<sub>2</sub>-IrO<sub>2</sub> electrode and analysis of electrocatalytic phenol oxidation performance

    REN Qiaolin<sup>1</sup>; WANG Xiaopeng<sup>1</sup>; YAN Wenjun<sup>2</sup>; YANG Tao<sup>3</sup>; CHEN Zehong<sup>1</sup>; WANG Jiaxin<sup>1</sup>; ZHENG Lijun<sup>4</sup>; WANG Zhongde<sup>1</sup>

    The Sn doped Ti/RuO<sub>2</sub>-IrO<sub>2</sub> electrode (SE) was fabricated for coking wastewater treatment to alleviate related environmental problems. The surface morphology, crystal structures and electrochemical properties were systematically characterized and analyzed, and the effects of electrolyte type, current density, electrolyte concentration, phenol concentration and solution pH on the phenol degradation performance of SE were also explored. The results confirmed that SE delivered excellent electroactivity under the optimal conditions (20 mA·cm<sup>-2</sup> of current density, 900 mg·L<sup>-1</sup> of NaCl, 300 mg·L<sup>-1</sup> of phenol and initial pH without adjustment) and the phenol degradation consisted with the first-order kinetic model. Meanwhile, the reactive oxygen species and a possible degradation mechanism were investigated. In addition, the SE also has excellent stability and practical applications. This study helps to develop a novel technology to treat coking wastewater for application.

    2025 05 [Abstract][OnlineView][Download 19247K]
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