Novel kinetic model for the simulation analysis of the butanol productivity of Clostridium acetobutylicum ATCC 824 under different reactor configurations

Acetone–butanol–ethanol(ABE)fermentation process can be exploited for the generation of butanol as biofuel,however it does need to overcome its low volumetric solvent productivity before it can commercially compete with fossil fuel technologies.In this regard,mathematical modelling and simulation analysis are tools that can serve as the base for process engineering development of biological systems.In this work,a novel phenomenological kinetic model of Clostridium acetobutylicum ATCC 824 was considered as a benchmark system to evaluate the behaviour of an ABE fermentation under different process configurations using both free and immobilized cells:single stage batch operation,fed-batch,single stage Continuous Stirred Tank Reactor(CSTR)and multistage CSTRs with and without biomass recirculation.The proposed model achieved a linear correlation index r~2=0.9952 and r~2=0.9710 over experimental data for free and immobilized cells respectively.The predicted maximum butanol concentration and productivity obtained were 13.08 g·L~(-1)and 1.9620 g·L~(-1)·h~(-1)respectively,which represents an increase of 1.01%and 990%versus the currently developed industrial scale process reported currently into the literature.These results provide a reliable platform for the design and optimization of the ABE fermentation system and showcase the adequate predictive nature of the proposed model.     

Kinetic study for the oxidation of cyclohexanol and cyclohexanone with nitric acid to adipic acid

The adipic acid is an important intermediate in the production of nylon, polyurethane and polyester resins. The industrial approach for preparing adipic acid is through the liquid catalytic oxidation of KA oil with nitric acid. In this work, a comprehensive model is developed for this reaction based on the kinetic study conducted in a continuous flow tubular reactor. The kinetic model fits well with the experimental results across the experimental conditions, and the average relative error between the calculated and experimental values is 5.7%. Results show that there was an induction period at the early stage of reaction. Moreover, it is found that at temperature range of 328-358 K, the formation rate of adipic acid strongly dependents on the temperature and nitric acid concentration. The developed model is used to predict the yield of adipic acid at 359-368 K. The work in this study could provide much knowledge for industrial tubular reactor design.     

搅拌设备的智能化化工预设计

传统的搅拌设备手工设计过程耗时且易出错 ,鉴于设计的复杂性和经验知识为主的特点 ,采用将其和专家系统技术相结合的方法 ,以实现搅拌设备的智能化计算机辅助设计。对搅拌设备的过程设计思想和算法 ,以及过程因素之间的相互关系进行了分析。认为如何将数值计算、定性推理和复杂的设计流程、大量的数据查询完美地结合起来 ,是系统开发的首要解决问题和实现的关键。对此智能化设计系统的实现方法、开发环境、功能结构和主要特点及难点进行了阐述。     

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

Gamma-aminobutyric acid (GABA) is a natural non-protein functional amino acid, which has potential for fermentation industrial production by Lactobacillus brevis. This work investigated the batch fermentation process and developed a kinetic model based on substrate restrictive model established by experimental data from L₂₅(5⁶) orthogonal experiments. In 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 model. Furthermore, 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 model. Finally, the accuracy 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, respectively. Therefore, the developed model is practical and convenient for the instruction of GABA fermentation production, and it has instructive significance for the industrial scale.     

Intellite3: A knowledge based expert system for control structure synthesis

This work describes an expert system for synthesis and design of control systems for chemical processing plants. We also outline the knowledge representation schemes for the expert system withobject oriented programming concepts on control system design,control objectives and their relationships to the knowledge structure shaped in this study —Task Frame Net Model. Based upon various control objectives, shortcut calculations, and several heuristics including control idioms,Intellite ³ -the expert system developed in this study — synthesizes interactively the plausible control structures for a specified distillation column and screens effectively those alternatives to find out the most reasonable one in The context of overall control objectives, operability, and other operational requirements.     

A novel kinetic model to describe 1,3-propanediol production fermentation by Clostridium butyricum

Clostridium butyricum is one of the best 1,3-propanediol producers due to the nonpathogenic, less byproducts, and energy-efficient fermentation process. In fermentation process, the relationship among substrate, product, and byproducts is intricate and hard to be analyzed. The present study is aimed at establishing a novel kinetic model not only based on biomass, substrate, and 1,3-propanediol, but also considering the byproduct concentration to describe 1,3-propanediol fermentation process by C. butyricum. The simulative result of the model fit well with that in the batch fermentation process. Furthermore, the model was also used to predict the result of fed-batch fermentation process after some modifications. The predicted result of model fit well with the data in experiment when glycerol was controlled at around 10 g/L. Thus, this novel kinetic model could serve as a tool for further optimization of the fermentation process, and could be improved for some other similar processes.     

A prototype expert system for hazard and operability studies

This paper describes the development of a prototype expert system for use in HAZard and OPerability (HAZOP) studies. The work is motivated by the fact that HAZOP studies are inherently logical exercises utilizing a process engineering knowledge base. The availability of an effective tool to aid engineers in design and operation would be of significant value.The knowledge domain required for HAZOP studies is wide. Hence the system must be built in modular form in order to be efficient. It must also be built in such a way that it is easy to incorporate additional knowledge into the system.The prototype developed in this work has been based on a PC version of Prolog. A basic inference engine, available in Prolog, has been enhanced and tailored into a user-friendly, interactive environment. Details of the knowledge organization and representation are discussed and an example session given. Further work is required to improve the system for serious industrial use through the addition of further knowledge modules, improved input—output facilities and optimization of the program.     

苯乙烯连续搅拌釜式本体聚合工业过程模拟

采用了机理分析建模法对苯乙烯工业本体预聚过程进行了模型化研究，并通过对流体在反应器中混合模式的分析，表明预聚釜可视作全混流（CSRT）反应器模型，此外对热聚合机理中的引发级数和终止反应进行了考察，利用预聚釜的工业数据确立了三分子引发，同时考虑偶合和歧化终止以及向溶剂链转移的反应机理模型，并选取了合适的动力学参数，然后利用工业装置采集的数据进行了模拟，从宏观转化率，平均分子量和微观分子量分布两个方面对模型进行了验证，模拟结果和工业数据符合得较好，该模型方程不仅能模拟稳态，非稳态预聚过程，同时也为装置开发新产品，改造扩建，优化操作方案等提供了理论基础。     

Determination of the heat of some aerobic fermentations

An accurate technique has been developed and applied to continuous measuring of the rate of heat production during a fermentation process. A special temperature control system was developed and used to monitor the heat quantity. The results were corrected for heat losses and gains based on the overall heat balance on the fermentor. The technique was used for precisely determining the rate of heat evolution of Aspergillus niger, Escherichia coli, Candida Upolytica, Candida intermedia and Candida utilis grown on etlianol and different carbohydrate and hydrocarbon sources. Based on the experimental data, a correlation between the rate of heat released and the rate of oxygen consumed has been determined as Q_term = 0.465 MJ /mol O₂ · Δ0₂. The total heat released also correlated well with the total oxygen consumed by the growing culture. The proportionality constant for this correlation was 0.461 MJ /mol O₂. The experimental results agreed well with the theoretical predictions and with those developed by the dynamic calorimetric technique. The derived correlations reported in this study arc useful for fermentation process design, optimization and control as well as indicators of microbial metabolic activity.     

Optimization of rice wine fermentation process based on the simultaneous saccharification and fermentation kinetic model☆

Chinese rice wine making is a typical simultaneous saccharification and fermentation(SSF) process.During the fermentation process,temperature is one of the key parameters which decide the quality of Chinese rice wine.To optimize the SSF process for Chinese rice wine brewing,the effects of temperature on the kinetic parameters of yeast growth and ethanol production at various temperatures were determined in batch cultures using a mathematical model.The kinetic parameters as a function of temperature were evaluated using the software Origin8.0.Combing these functions with the mathematical model,an appropriate form of the model equations for the SSF considering the effects of temperature were developed.The kinetic parameters were found to fit the experimental data satisfactorily with the developed temperature-dependent model.The temperature profile for maximizing the ethanol production for rice wine fermentation was determined by genetic algorithm.The optimum temperature profile began at a low temperature of 26 °C up to 30 h.The operating temperature increased rapidly to 31.9 °C,and then decreased slowly to 18 °C at 65 h.Thereafter,the temperature was maintained at18 °C until the end of fermentation.A maximum ethanol production of 89.3 g·L~(-1)was attained.Conceivably,our model would facilitate the improvement of Chinese rice wine production at the industrial scale.     

通用工程数据处理系统在耐火材料工厂设计中的应用

“通用工程数据处理系统”是一套智能化的工程数据处理系统,在Windows下用C++Builder 开发而成。系统设计中引入了专家系统的设计思想,实现了数据处理的智能化,具有知识获取、数据存储、知识推理、统计分析、检索排序、数据转换等功能,全部操作可视化,简便快捷,为各类工程数据处理提供了安全、通用、简便的集成环境,具有很高的实用价值。     

Die Aceton-Butanol-Gärung: Grundlage für einen modernen biotechnologischen Prozeß?

Acetone-butanol fermentation: basis of a modern biotechnological process? Acetone-butanol fermentation was performed on a large industrial scale for about forty years. After the Second World War it was unable to compete with petrochemical processes and renewed interest in this fermentation has developed only during the last decade. It has led to a vast increase of our knowledge of the biochemistry of acetone-butanol formation and of the genetics of the producing organism, Clostridium acetobutylicum. Considerable progress was also made in defining optimal fermentation conditions. However, the biotechnological process is not yet economically feasible, primarily because low final product concentrations engender high product recovery costs.     

Alcoholic Fermentation with Self‐Flocculating Yeast in a Tower Upflow Reactor

Ethanol production using self‐flocculating yeast in a batch tower upflow reactor system operating with a recirculation loop was examined. Ethanol productivity, yield, and residual sucrose concentration were evaluated experimentally according to a central composite design with initial cell and sucrose concentrations and recirculation flow rate as independent variables. Yeast cell concentration strongly influenced the reactor performance. Alcoholic fermentation was conducted using this strain and reactor configuration which allowed for high productivity and high sucrose conversion. The ethanol yield was comparable with industrial yields. A kinetic study of the fermentation process under optimized conditions was performed using the experimental data and considering inhibition by sucrose and ethanol.     

Gas Fermentation Expands the Scope of a Process Network for Material Conversion

Biotechnological fermentation is a well-established process, however, it is far from being fully understood and exploited. A new area of fermentation technology that has evolved over the recent decades is gas fermentation. Many microorganisms have been reported in literature to be capable of utilizing a variety of gases such as CO, CO₂, H₂, and CH₄ under anaerobic or aerobic conditions as their main carbon and/or energy source. Mostly waste stream gases from industrial plants or those that can be produced via the gasification of solids are investigated. This review focuses on the currently available scientific knowledge about gas fermentation processes, particularly anaerobic syngas fermentation and aerobic methane fermentation. Gas fermentation processes are compared with aerobic and anaerobic fermentation processes based on dissolved solid substrates. Also, the potential of gas fermentation when integrated into a biotechnological network of processes is outlined.     

DEVELOPMENTS IN COMPUTER-AIDED DRYER SELECTION

This paper describes recent advances in the development of a fuzzy expert system for food dryer selection. An earlier version, which was restricted to batch dryers, has now been extended to include continuous dryers. The modular approach originally proposed by the present authors was adopted. The current implementation of the system includes three knowledge bases: the mode (batch-continuous) selector, the batch-dryer selector, and the continuous-dryer selector. A blackboard architecture was used to facilitate full data interchange between the three knowledge bases. A user interface and a scheduler were developed to automate the system. Examples of ancillary programs (design, costing, help, applications) have also been developed. Satisfactory predictions were obtained using the selection algorithm. Typical examples are presented in case studies.     

Estimation of Kinetic Parameters for Hydrogenation Reactions Using a Genetic Algorithm

The kinetics of acetylene hydrogenation in a fixed‐bed reactor of a commercial Pd/Al₂O₃ catalyst has been studied. The hydrogenation reactor considered in this work is an essential part of a vinyl chloride monomer (VCM) plant. Three well‐known kinetic models were used to simulate the hydrogenation reactor under industrial operating conditions. Since none of the models provide appropriate prediction, the industrial data and calculated values were compared and optimum kinetic parameters were evaluated utilizing a genetic algorithm (GA) technique. The best kinetic parameters for the three models were determined under specified industrial operating conditions. The hydrogenation reactor was simulated using the estimated optimum kinetic parameters of the three models. Simulation results from the three models were compared to industrial data and the best kinetic model was found. This kinetic model with the evaluated optimum kinetic parameters can well predict the behavior of the industrial hydrogenation reactor to improve the performance of the process.     

Understanding the scale-up of fermentation processes from the viewpoint of the flow field in bioreactors and the physiological response of strains

The production capability of a fermentation process is predominately determined by individual strains, which ultimately affected ultimately by interactions between the scale-dependent flow field developed within bioreactors and the physiological response of these strains. Interpreting these complicated interactions is key for better understanding the scale-up of the fermentation process. We review these two aspects and address progress in strategies for scaling up fermentation processes. A perspective on how to incorporate the multiomics big data into the scale-up strategy is presented to improve the design and operation of industrial fermentation processes.     

工厂供电系统故障诊断专家系统的设计

工厂供电系统的安全运行对工业企业来说至关重要 ,特别是对于化工企业 ,如何快速判断和切除故障非常关键。介绍了利用专家系统技术开发供电系统故障诊断系统的结构特点、主要功能 ,重点阐述了系统中推理机的构造、知识库的描述及网络图形显示、模拟倒闸操作等功能的实现。该系统是用VC ++开发成功的 ,并对用VC ++实现知识的框架结构表达做了详细的说明     

Optimal hybrid modeling approach for polymerization reactors using parameter estimation techniques

The dynamics of polymerization catalytic reactors have been investigated by many researchers during the past five decades; however, the emphasis of these studies was directed towards correlating process model parameters using empirical investigation based on small scale experimental setup and not on real process conditions. The resulting correlations are of limited practical use for industrial scale operations. A statistical study for the relative correlation of each of the effective process parameters revealed the best combination of parameters that could be used for optimizing the process model performance. Parameter estimation techniques are then utilized to find the values of these parameters that minimize a predefined objective function. Published real industrial scale data for the process was used as a basis for validating the process model. To generalize the model, an artificial neural network approach is used to capture the functional relationship of the selected parameters with the process operating conditions. The developed ANN-based correlation was used in a conventional fluidized catalytic bed reactor (FCR) model and simulated under industrial operating conditions. The new hybrid model predictions of the melt-flow index and the emulsion temperature were compared to industrial measurements as well as published models. The predictive quality of the hybrid model was superior to other models. The suggested parameter estimation and modeling approach can be used for process analysis and possible control system design and optimization investigations.     

肌苷发酵和分离耦合过程的动力学

许多发酵过程都受到高浓度产物的抑制,肌苷发酵亦存在明显的产物反馈抑制作用。为了降低产物抑制效应,采取发酵和离子交换分离产物、流加补料结合起来的耦合发酵方法。本文结合肌苷合成代谢途径,建立了肌苷耦合发酵动力学模型,用于指导工业生产。