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kinetic modeling of gamma-aminobutyric acid production by Lactobacillus brevis based on pH-dependent model and rolling correction

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Chinese Journal of Chemical Engineering 2022年第10期50卷 352-360页

作者： Min Wu Juanjuan Ding Zhaofeng Zhang Shengping You Wei Qi Rongxin Su Zhimin He Chemical Engineering Research Center School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China State Key Laboratory of Chemical Engineering Tianjin UniversityTianjin 300350China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China Tianjin Key Laboratory of Membrane Science and Desalination Technology Tianjin UniversityTianjin 300072China

Gamma-aminobutyric acid(GABA)is a natural non-protein functio nal amino acid,which has potential for fermentation industrial production by Lactobacillus *** work investigated the batch fermentation process and developed a kinetic model based on substrate restrictive model established by experimental data from L25(5~6)orthogonal *** this study,the OD600 value of fermentation broth was fixed to constant after reaching its maximum because the microorganism death showed no effect on the enzyme activity of glutamate decarboxylase(GAD).As pH is one of the key parameters in fermentation process,a pH-dependent kinetic model based on radial basis function was developed to enhance the practicality of the ***,as to decrease the deviations between the simulated curves and the experimental data,the rolling correction strategy with OD600 values that was measured in real-time was introduced into this work to modify the ***,the accu racy of the rolling corrected and pH-dependent model was validated by good fitness between the simulated curves and data of the initial batch fermentation(pH 5.2).As a result,this pH-dependent kinetic model revealed that the optimal pH for biomass growth is 5.6-5.7 and for GABA production is about 5,***,the developed model is practical and convenient for the instruction of GABA fermentation production,and it has instructive significance for the industrial scale.

关键词： kinetic modeling Fermentation Gamma-aminobutyric Lactobacillus brevis pH control Rolling correction

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kinetic modeling the Formation of Low-mature Gases and Analysis of the Possibility to Be Accumulated

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Acta Geologica Sinica(English Edition) 2008年第3期82卷 537-542页

作者： SHUAI Yanhua WANG Hui ZHANG Shuichang SU Aiguo Research Center of Petroleum Geology Research Institute of Petroleum Exploration and Development PetroChina Beijing 100083 China

At present, shallow gases have received much attention due to low cost in exploration and production. Low-mature gases, as one significant origin to shallow gas, turns to be an important research topic. The present understanding of low-mature gases is confined within some geological cases, and few laboratory studies have been reported. Therefore, the potential and characters of low- mature gases are not clear up to now. Here, two premature samples （one coal and the other shale） were pyrolyzed in a gold confined system. The gaseous components including hydrocarbon gases and non-hydrocarbon gases were analyzed. Based on kinetic modeling, the formation of low-mature gases was modeled. The results showed that during low mature stage, about 178 mL/gTOC gas was generated from the shale and 100 mL/gTOC from the coal. Two third to three fourth of the generated gases are non-hydrocarbon gases such as H2S and CO2. The total yields of C1-5 for the two samples are almost the same, 30-40 mL/gTOC, but individual gaseous hydrocarbon is different. The shale has much lower C1 but higher C2-5, whereas the coal has higher C1 but lower C2-5. Hydrocarbon gases formed during low-mature stage are very wet. The stable carbon isotope ratios of methane range from -40‰ to -50‰ （PDB）, in good consistence with empiric criterion for low-mature gases summed up by the previous researchers. The generation characters suggest that the low-mature gases could be accumulated to form an economic gas reservoir, but most of them occur only as associated gases.

关键词： low-mature gases kinetic modeling carbon isotope ratio of methane potential of C1-5

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kinetic modeling of Methanol to Olefins(MTO)Process on SAPO-34 Catalyst

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China Petroleum Processing & Petrochemical Technology 2013年第3期15卷 86-90页

作者： Pu Jianglong Weng Huixin East China University of Science and Technology

A kinetic model of MTO process over the SAPO-34 catalyst considering the effect of water and coke deposition has been *** model takes into account three steps of the MTO reaction in which the products cover 5 lumped *** water in the feed not only reduces the concentration of methanol but also alleviates the deactivation of SAPO-34 *** kinetic parameters have been estimated by the least square *** has been proved that the calculated values in the kinetic model are in good agreement with the experimental values.

关键词： methanol to olefin process(MTO) kinetic modeling SAPO-34 deactivation

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kinetic modeling of cement slurry synthesized with Henna extract in oil well acidizing treatments

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Petroleum 2016年第2期2卷 196-207页

作者： Amir Hossein Aghajafari Seyed Reza Shadizadeh Khalil Shahbazi Hadi Tabandehjou Department of Petroleum Engineering Ahwaz Faculty of Petroleum EngineeringPetroleum University of TechnologyAbadanIran National Iranian Drilling Company(NIDC) AhwazIran

Acidizing treatment in petroleum reservoirs is a short-term and viable strategy to preserve the productivity of a *** is a major concern for the degradation of cement sheath integrity,leading to poor zonal isolation and environmental ***,it is essential to understand how the cement behaves when attacked by hydrochloric *** this study,a cement slurry by incorporation of the Henna extract,as an environmentally friendly cement additive,was synthesized as a potential solution to solve this *** characteristics of the treated cement slurry were compared with a reference slurry(w/c?0.44)which is composed of only cement and water.A kinetic study was carried out to evaluate the adsorption behavior of the cement slurries exposed to an acid solution with 0.1 M HCl in a range of 25 to 55C *** features of the cement slurries were evaluated by multiple analytical techniques such as XRD,FTIR,TG,and DSC *** the experimental data,it is concluded that the second-order Lagergren kinetic model revealed to be the best in describing kinetic isotherms taken,because the margin between experimental and calculated values was minor for this *** results of the characterization and HCl interaction kinetic studies underlined the prominent protective role of Henna extract-modified cement slurry in the enhancement of the cement resistance against acid attack and utilization in environmentally favorable oil well acidizing treatments.

关键词： Oil well cement Henna extract Solid/solution interaction Environment protection kinetic modeling

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A comparative single-pulse shock tube experiment and kinetic modeling study on pyrolysis of cyclohexane,methylcyclohexane and ethylcyclohexane

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Defence Technology（防务技术） 2023年第2期20卷 137-148页

作者： Jin-hu Liang Shu-tong Cao Fei Li Xiao-liang Li Rui-ning He Xin Bai Quan-De Wang Yang Li School of Environmental and Safety Engineering North University of ChinaTaiyuan030051People's Republic of China Science and Technology on Combustion Internal Flow and Thermostructure LaboratorySchool of AstronauticsNorthwestern Polytechnical UniversityXi'an 710072People's Republic of China Low Carbon Energy Institute and School of Chemical Engineering China University of Mining and TechnologyXuzhou 221008People's Republic of China

The pyrolysis of cyclohexane,methylcyclohexane,and ethylcyclohexane have been studied behind reflected shock waves at pressures of 5 and10 bar and at temperatures of 930-1550 K for 0.05%fuel diluted by Argon.A single-pulse shock tube(SPST)is used to perform the pyrolysis experiments at reaction times varying from 1.65 to 1.74 *** products are obtained and quantified using gas chromatography analysis.A flame ionization detector and a thermal conductivity detector are used for species identification and *** modeling has been performed using several detailed and lumped chemical kinetic *** in modeling results among the kinetic models are *** path analysis and sensitivity analysis are performed to determine the important reactions controlling fuel pyrolysis and their influence on the predicted concentrations of reactant and product species *** present work provides new fundamental knowledge in understating pyrolysis characteristics of cyclohexane compounds and additional data set for detailed kinetic mechanism development.

关键词： Cyclohexane Alkylated cyclohexane Single-pulse shock tube Pyrolysis kinetic modeling

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Identical full-scale biogas-lift reactors(BLRs) with anaerobic granular sludge and residual activated sludge for brewery wastewater treatment and kinetic modeling

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Journal of Environmental Sciences 2013年第10期25卷 2031-2040页

作者： Fu Xu Zhenxing Huang Hengfeng Miao Hongyan Ren Mingxing Zhao Wenquan Ruan School of Environment and Civil Engineering Jiangnan University

Two identical full-scale biogas-lift reactors treating brewery wastewater were inoculated with different types of sludge to compare their operational conditions, sludge characteristics, and kinetic models at a mesophilic temperature. One reactor （R1） started up with anaerobic granular sludge in 12 weeks and obtained a continuously average organic loading rate （OLR） of 7.4 kg chemical oxygen demand （COD）/（***）, COD removal efficiency of 80%, and effluent COD of 450 mg/L. The other reactor （R2） started up with residual activated sludge in 30 weeks and granulation accomplished when the reactor reached an average OLR of 8.3 kg COD/（m^3·day）, COD removal efficiency of 90%, and effluent COD of 240 mg/L. Differences in sludge characteristics,biogas compositions, and biogas- lift processes may be accounted for the superior efficiency of the treatment performance of R2 over R1. Grau second-order and modified StoverKincannon models based on influent and effluent concentrations as well as hydraulic retention time were successfully used to develop kinetic parameters of the experimental data with high correlation coefficients （R2 〉 0.95）, which further showed that R2 had higher treatment performance than R1. These results demonstrated that residual activated sludge could be used effectively instead of anaerobic granular sludge despite the need for a longer time.

关键词： anaerobic granular sludge residual activated sludge biogas-lift reactor brewery wastewater kinetic modeling

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Molecule-based kinetic modeling by Monte Carlo methods for heavy petroleum conversion

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Science China Chemistry 2013年第11期56卷 1608-1622页

作者： de OLIVEIRA Luís Pereira VERSTRAETE Jan J. KOLB Max IFP Energies nouvelles Rond-point de l'échangeur de Solaize-BP 369360 SolaizeFrance Laboratoire de Chimie cole Normale Supérieure69364 Lyon Cedex 07France

A methodology for kinetic modeling of conversion processes is *** proposed approach allows to overcome the lack of molecular detail of the petroleum fractions and to simulate the reactions of the process by means of a two-step *** the first step,a synthetic mixture of molecules representing the feedstock is generated via a molecular reconstruction method,termed SR-REM molecular *** the second step,a kinetic Monte Carlo method,termed stochastic simulation algorithm(SSA),is used to simulate the effect of the conversion reactions on the mixture of *** resulting methodology is applied to the Athabasca vacuum residue *** adequate molecular representation of the vacuum residue is obtained using the SR-REM *** reaction simulations present a good agreement with the laboratory data for Athabasca vacuum residue *** addition,the proposed methodology provides the molecular detail of the vacuum residue conversion throughout the reactions simulations.

关键词： Monte-Carlo molecular reconstruction kinetic modeling stochastic simulation algorithm vacuum residue hydrocracking

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Application of Discrete Lumped kinetic modeling on Vacuum Gas Oil Hydrocracking

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China Petroleum Processing & Petrochemical Technology 2013年第2期15卷 67-73页

作者： Han Longnian Fang Xiangchen Peng Chong Zhao Tao Liaoning Shihua University SINOPEC Fushun Research Institute of Petroleum and Petrochemicals

The kinetic model of vacuum gas oil （VGO） hydrocracking based on discrete lumped approach was investigated, and some improvement was put forward at the same time in this article. A parallel reaction scheme to describe the conver- sion of VGO into products （gases, gasoline, and diesel） proposed by Orochko was used. The different experimental data were analyzed statistically and then the product distribution and kinetic parameters were simulated by available data. Fur- thermore, the kinetic parameters were correlated based on the feed property, reaction temperature, and catalyst activity. An optimization code in Matlab 2011b was written to fine-me these parameters. The model had a favorable ability to predict the product distribution and there was a good agreement between the model predictions and experiment data. Hence, the ki- netic parameters indeed had something to do with feed properties, reaction temperature and catalyst activity.

关键词： hydrocracking kinetic modeling vacuum gas oil (VGO) optimization code parallel reaction scheme

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Chemical vapor infiltration of pyrocarbon from methane pyrolysis: kinetic modeling with texture formation

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Science China Materials 2019年第6期62卷 840-852页

作者： Chunxia Hu Hejun Li Shouyang Zhang Wei Li Ni Li State Key Laboratory of Solidification Processing C/C Composites Research CenterNorthwestern Polytechnical University Department of Mechanical Engineering California State UniversityLos Angeles

A complete mechanism of methane pyrolysis is proposed for chemical vapor infiltration of pyrocarbon with different textures, which contains a detailed homogeneous mechanism for gas reactions and a lumped heterogeneous mechanism for pyrocarbon deposition. This model is easily applied to simulate gas compositions and pyrocarbon deposition in a vertical hot-wall flow reactor in the temperature range of 1,323–1,398 K without any adjusting parameters and presents better results than previous mechanisms. Results have shown that the consumption of methane and the production of hydrogen are well enhanced due to pyrocarbon deposition. Pyrocarbon deposition prevents the continuously increasing of acetylene composition and leads to the reduction in the mole fraction of benzene at long residence times in the gas phase. The carbon growth with active sites on the surface is the controlling mechanism of pyrocarbon deposition. C1 species is the precursor of pyrocarbon deposition at 1,323 K,and the primary source over the whole temperature range. As temperature increases, gas phase becomes more mature and depositions from acetylene, benzene and polyaromatic hydrocarbons become more prevalent. A general pyrocarbon formation mechanism is derived with the specific precursors and illustrates that the maturation of gas compositions is beneficial to forming planar structures with hexagonal rings or pentagon-heptagon pairs, namely, high textured pyrocarbon. The results are in well agreement with experiments.

关键词： kinetic modeling pyrolytic carbon texture chemical vapor infiltration methane

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Effect of solvent on the initiation mechanism of living anionic polymerization of styrene:A computational study

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Chinese Journal of Chemical Engineering 2024年第5期69卷 135-142页

作者： Shen Li Yin-Ning Zhou Zhong-Xin Liu Zheng-Hong Luo School of Chemical Engineering and Technology Hainan UniversityHaikou 570228China Department of Chemical Engineering School of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and *** this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory(DFT)calculations and kinetic *** terms of mechanism,it is found that the stronger the solvent polarity,the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent ***,we also found that the stronger the solvent polarity,the higher the monomer initiation energy barrier and the smaller the initiation rate ***,initiation is more favorable at lower temperatures based on the calculated results ofΔG_(TS).Finally,the kinetic characteristics in different solvents were further examined by kinetic *** is found that in benzene and n-pentane,the polymerization rate exhibits first-order ***,slow initiation and fast propagation were observed in tetrahydrofuran(THF)due to the slow free ion formation rate,leading to a deviation from first-order kinetics.

关键词： Living anionic polymerization Solvent effect Reaction kinetics Computational chemistry Mathematical modeling kinetic modeling

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