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SIMULATION OF EFFECTS OF REACTIVE IMPURITIES ON PROPYLENE POLYMERIZATION IN LOOP REACTORS THROUGH GENERATION FUNCTION TECHNIQUE

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Chinese Journal of Polymer Science 2007年第4期25卷 365-377页

作者：罗正鸿 Department of chemical and biochemical engineering Xiamen University

The estimation of the amount of reactive impurities in a loop reactor is of strategic importance to the propylene polymerization industry. It is essential to investigate the level of impurities in order to develop reliable monitoring and control strategies. This paper described one approach based on generation function technique with the following two steps. First, a new mechanism for propylene polymerization was proposed by considering the effects of the reactive impurities in the material on the propylene polymerization. Second, a series of equations of population balance for the propylene polymerization in loop reactors were established based on the proposed mechanism. Accordingly, the equations were transformed into the mathematic matrix through the generation function technique to investigate the effects of the reactive impurities on the propylene polymerization. Significant effects of the reactive impurities were analyzed through computational simulation. The results show that the concentration of active centre on catalysts and the polymerization conversion both decrease with the increase of the initial concentration of any reactive impurity; hydrogen concentration decreases with the increase of the initial concentration of ethylene or butylenes, whereas, it increases with the increase of the initial concentration of propadiene; the simulated weight average molecular weight and the molecular weight distribution index of polymer resins both increase with the increase of the initial concentration of ethylene or butylenes. They decrease with the increase of the initial concentration of propadiene.

关键词： Propylene polymerization Reactive impurity Generation function technique Loop reactor

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Measurement and correlation of solid–liquid phase equilibria for binary and ternary systems consisting of N-vinylpyrrolidone, 2-pyrrolidone and water

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Chinese Journal of chemical engineering 2018年第4期26卷 806-811页

作者： Ao Su Sifang Li Department of chemical and biochemical engineering College of Chemistry and Chemical Engineering Xiamen University

The solid–liquid equilibria(SLE)for binary and ternary systems consisting of N-Vinylpyrrolidone(NVP),2-Pyrrolidone(2-P)and water are *** phase diagrams of NVP(1)+2-P(2),NVP(1)+water(2),NVP(1)+2-P(2)+1 wt%water(3)and NVP(1)+2-P(2)+2 wt%water(3)are identified as simple eutectic type with the eutectic points at 263.75 K(x_(1E)=0.5427),251.65 K(x_(1E)=0.3722),260.25 K(x_(1E)=0.5031)and256.55 K(x_(1E)=0.4684),*** phase diagram of 2-P(1)+water(2)has two eutectic points(x_(1E)=0.1236,T_E=259.15 K and x_(1E)=0.7831,T_E=286.15 K)and one congruent melting point(x_(1C)=0.4997,T_C=303.55 K)because of the generation of a congruently melting addition compound:2-P·H_*** ideal solubility and the UNIFAC models were applied to predict the SLE,while the Wilson and NRTL models were employed in correlating the experimental *** best correlation of the SLE data has been obtained by the Wilson model for the binary system of NVP+*** UNIFAC model gives more satisfactory predictions than the ideal solubility model.

关键词： Phase equilibria Thermodynamics Model N-vinylpyrrolidone 2-Pyrrolidone Water

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CFD modeling using heterogeneous reaction kinetics for catalytic dehydrogenation syngas reactions in a fixed-bed reactor

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Particuology 2013年第6期11卷 703-714页

作者： Xiaomin Chen Jiu Dai Zhenghong Luo Department of chemical and biochemical engineering College of Chemistry and Chemical EngineeringXiamen University

A comprehensive 2D computational fluid dynamics （CFD） model was developed to simulate the flow behavior and catalytic dehydrogenation reaction of syngas in a heterogenous fixed-bed reactor （FBR）. The model combined the porous medium CFD model with a reaction kinetics model. To acquire an accu- rate reaction kinetics model, a comprehensive reaction mechanism was studied for the heterogeneous catalytic dehydrogenation reaction ofsyngas over a supported metal catalyst. Based on the reaction mech- anism and a statistical test, a reliable kinetics model was proposed. The CFD model combined with the above kinetics model was validated with one set of experimental data. The CFD model was also used to predict key reaction variable distributions such as the temperature and the component concentrations in the reactor.

关键词： Reaction engineering Multiphase reactor Packed bed Kinetics CFD Syngas dehydrogenation

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Effect of manganese and potassium addition on CeO_2-Al_2O_3 catalyst for hydrogenation of benzoic acid to benzaldehyde

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Journal of Rare Earths 2009年第5期27卷 723-727页

作者：程党国侯春阳陈丰秋詹晓力 Department of chemical and biochemical engineering Zhejiang University

A series of Mn/CeO2-Al2O3 and K/CeO2-Al2O3 catalysts for hydrogenation of benzoic acid to benzaldehyde were prepared to in- vestigate the effect of Mn, K addition on CeO2-Al2O3 catalyst. X-ray diffraction (XRD) and H2-temperature-programmed reduction (H2-TPR) results suggested that the interaction between CeO2 and MnOx enhanced the reducibility of catalysts and therefore benzoic acid conversion. The addition of K increased the number of basic number on the catalyst which leads to a high selectivity to benzaldehyde, but excessive addition imposed negative effects on the catalyst performance. A Mn-K/CeO2-Al2O3 catalyst was developed and investigated in the reaction. The simultaneous addition of Mn and K enhanced not only the catalytic activity but also the capacity to resist the coke formation over catalyst.

关键词： benzaldehyde benzoic acid CeO2 manganese potassium rare earths

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3D multiphase flow simulation of Marangoni convection on reactive absorption of CO_(2) by monoethanolamine in microchannel

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Chinese Journal of chemical engineering 2022年第3期35卷 370-377页

作者： Shuai Chen Jiahong Lan Yu Zhang Jia Guo Zhikai Cao Yong Sha Department of chemical and biochemical engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

A multiphase flow 3D numerical simulation method employing the coupled volume of fluid(VOF)and level set model is established to study the reactive absorption of CO_(2)by the monoethanolamine(MEA)aqueous solution in a falling film *** on the flow-reaction-mass transfer model of the MEA-CO_(2)system in the falling film microchannel,the enhancement effect of the Marangoni convection in this reactive absorption process is *** enhancement factor of the Marangoni convection obtained in this work is in good agreement with experimental results in the *** consideration of the absorption ratio as well as the enhancement effect of the Marangoni convection,the influence of different MEA concentrations on absorption of CO_(2)is ***,the appropriate MEA concentration for absorption enhanced by the Marangoni convection is acquired.

关键词： Numerical simulation Microchannel Falling film Marangoni convection MEA-CO_(2)

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Investigation on catalytic distillation for ethyl acetate production with different catalytic packing structures

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Chinese Journal of chemical engineering 2023年第1期53卷 63-72页

作者： Zhiwei Wang Yu Zhang Zhi Zhang Daowei Zhou Zhikai Cao Yong Sha Department of chemical and biochemical engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

The catalytic packing is the core component of the catalytic distillation,and how the catalyst exists in the packing has significant influence on the *** investigate the effect of catalyst packings on the catalytic distillation process,the classical ethyl acetate reactive distillation system was utilized,and a supported catalytic packing(SCP)was prepared in comparison with the conventional tea-bag catalytic packing(TBP).Laboratory scale experiments showed that the ethyl acetate conversion of the SCP was superior to the TBP at a low catalyst *** effects of reaction kinetics,mass transfer performance and actual catalytic efficiency of the packings on this process were regarded as reasons and studied by combining the experiments and numerical *** suggested that the relatively immediate“in-situ separation”caused by the rapid reaction kinetics and better mass transfer performance of SCP may be a main reason for the difference of the conversion.

关键词： Catalytic packing Ethyl acetate Catalytic distillation Mass transfer Esterification Reaction kinetics

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Supported catalytic packing prepared from ceramic packing for reactive distillation of ethyl acetate

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Chinese Journal of chemical engineering 2022年第10期50卷 205-214页

作者： Zhiwei Wang Jiannan Shi Xiaonan Liu Zhikai Cao Yong Sha Department of chemical and biochemical engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

In this work,a strategy of"etching-modification filling-graft copolymerization"was proposed to load the acidic ionic polyionic liquid on the smooth ceramic *** this way,commercial ceramic Raschig rings were successfully transformed into the supported catalytic packing for the reactive distillation,and were further evaluated with esterification reaction of ethyl acetate by means of the fully mixed reactor,the ultrasonic destruction,the cyclic catalysis reaction and the lab-scale distillation column *** catalyst coating has good adhesion with the *** can withstand 24 h of ultrasound damage and shows good stability in three cycle catalytic *** kind of coated catalyst has better catalytic activity than the commercial Amberlyst 15 *** the lab-scale reaction distillation,the supported catalyst Raschig ring can achieve a higher conversion in comparison with the tea bag catalytic packing of Amberlyst 15 dry under some conditions.

关键词： Supported catalyticpacking Ethyl acetate Reactive distillation Bonding strength

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Hierarchical monolithic carbon with high transfer performance for hydrogen evolution reaction

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Journal of Energy Chemistry 2022年第10期31卷 41-48,I0002页

作者： Yazhang Lin Weijie Zhu Yunhua Li Department of chemical and biochemical engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005FujianChina

Electrocatalysis is an efficient green process for energy ***,for gas-related electrocatalytic reaction,sluggish gas transport has inhibited significantly the promotion of electrocatalytic ***,hierarchical monolithic material 3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) were prepared by3 D printing polyethyleneimine cross-linking oxygenated carbon nanotube and following nickel electrodeposition.3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) have regular pore structure in consistence with3 D printing design and uniform dispersed *** bonds and carbon defects are presented on the surface of 3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) as well as uniformly distributed β-Ni(OH)_(2) on3 DPC-650@Ni/Ni(OH)_(2).3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) present lower overpotentials of 322 and160 mV for hydrogen evolution reaction in 1.0 M KOH at 50 mA cm^(-2),*** ordered channel,high turnover frequency and electrochemically active surface area,hydrophilic and aerophobic properties result in the higher performance of 3 DPC-650 and 3 DPC-650@Ni/Ni(OH)_(2) than traditional supports(carbon paper,carbon cloth,and nickel foam) and *** work provides an efficient pathway for design and preparation of the monolithic electrocatalyst and electrode used for electrochemical reactions where gas is involved.

关键词： 3D printing Hierarchical structure Monolith Mass transfer Charge transfer Hydrogen evolution reaction

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Determination of particle size distribution by multi-scale analysis of acoustic emission signals in gas-solid fluidized bed

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2011年第4期12卷 260-267页

作者： Cong-jing REN Jing-dai WANG Di SONG Bin-bo JIANG Zu-wei LIAO Yong-rong YANG State Key Laboratory of chemical engineering Department of Chemical and Biochemical Engineering Zhejiang University Hangzhou 310027 China

Particle size distribution(PSD) is an important parameter in the process of fluidization,and it always plays a crucial role in a gas-solid fluidized system.A PSD model for on-line PSD determination based on acoustic emission(AE) measurement was developed according to the mechanism of particle collision with the inner wall of the cylinder and multi-scale wavelet decomposition *** PSD model illuminates the quantitative relationship between the energy percentage of AE signals for different scales and the PSD,which indicates the feasibility of the application of the PSD *** were undertaken both in lab and plant gas-solid fluidized setup with polyethylene particles,and the parameters of the PSD model were calibrated and *** experimental conditions and results proved that the PSD model was suitable for on-line measurement and was sufficiently sensible and *** agglomeration,the PSD model also showed exact serviceability on detecting the onset of agglomeration by abnormal PSD,and the result agreed with that from the radiation ***,AE measurement was found to be a reliable and credible means for understanding the PSD information that affects the behavior of a system,which can provide valuable guidance for practical applications.

关键词： Particle size distribution(PSD) Acoustic emission(AE) Fluidized bed Multi-scale Agglomeration

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KINETICS OF SUSPENDED EMULSION POLYMERIZATION OF METHYL METHACRYLATE

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Chinese Journal of Polymer Science 2004年第6期22卷 543-548页

作者：包永忠 Department of chemical and biochemical engineering Zhejiang University Hangzhou 310027 China

The kinetics of suspended emulsion polymerization of methyl methacrylate (MMA), in which water acted as the dispersed phase and the mixture of NMA and cyclohexane as the continuous phase, was investigated. It showed that the initial polymerization rate (R-p0) and steady-state polymerization rate (R-p) were proportional to the mass ratio between water and oil phase, and increased as the polymerization temperature, the potassium persulphate concentration ([I]) and the Tween20 emulsifier concentration ([S]) increased. The relationships between the polymerization rate and [I] and [S] were obtained as follows: R-p0 proportional to [I](0.73)[S](0.32) and R-p proportional to [I](0.71)[S](0.23). The above exponents were close to those obtained from normal MMA emulsion polymerization. It also showed that the average molecular weight of the resulting poly(methyl methacrylate) decreased as the polymerization temperature, [I] and [S] increased. Thus, MMA suspended emulsion polymerization could be considered as a combination of many miniature emulsion polymerizations proceeding in water drops and obeyed the classical kinetics of MMA emulsion polymerization.

关键词： suspended emulsion polymerization methyl methacrylate polymerization rate average molecular weight and molecular weight distribution

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