检索结果-内蒙古大学图书馆

CHISA 2006 - 17th International Congress of Chemical and process Engineering

作者： Koroishi, E.T. Boss, E.A. Maciel Filho, R. State University of Campinas - UNICAMP Laboratory of Optimization Design and Advanced Control - LOPCA Post office box: 6066 13081-970 Campinas Brazil

ISBN: (纸本)8086059456

Freeze drying is a separation process based on sublimation phenomenon, where the solvent is removed as vapor of the frozen substance. The main advantage of this process is to obtain high quality product due to low induction of the thermal degradation. This process allows the retention of the volatilities materials responsible for flavor and may provide a rigid structure of the dried material, which is usually required. Moreover, other advantages of this process are: water low content in the dried product;no need to preserve the product in refrigerated place;reduction of the product weight and volume that facilitates the stockage and transport and increase of the product shelf life. The freeze-drying process can be used in dehydrating of foods (such as coffee, soups and fruits), pharmaceuticals and biotechnological materials. The fundamental stages involved in freeze drying process are: freezing, primary and secondary drying stages. The freezing stage represents the first separation step and the performance of the overall freeze drying process depends significantly of this stage. In the primary freezing stage, the frozen solvent is removed by sublimation. In the secondary drying stage the sublimed water is removed. In this work, the no pasteurized orange juice freeze drying process was considered, and the main objective is to develop a procedure that allows to preserve the flavor and the vitamins of the juice. The vitamin C, or ascorbic acid is one of the most important vitamins found in citric fruit juice such as orange juice. There is variation in the ascorbic acid quantity present in the orange juice due to variety, place where the fruit grows, maturity and fruit extraction method, so that the process should be tailored to couple with such variations. Brazil became the orange first world producer since 80's. The main product extracted from oranges is the juice. In addition to orange juice, various by-products such as essential oils, d'limonene and citrus pulp pell

关键词： Fruit juices

来源：评论

学校读者我要写书评

暂无评论

Modeling the influence of temperature on alcoholic fermentation kinetics using a genetic algorithm

Modeling the influence of temperature on alcoholic fermentat...

引用

CHISA 2006 - 17th International Congress of Chemical and process Engineering

作者： Rivera, E. A. Ccopa Costa, A.C. Maciel Filho, R. Laboratory of Optimization Design and Advanced Control Faculty of Chemical Engineering State University of Campinas P. O. Box 6066 13081-970 Campinas SP Brazil

ISBN: (纸本)8086059456

In this work, an adaptive hybrid model that consider the effect of temperature on the kinetics was implemented. The hybrid model for bioethanol production by continuous extractive fermentation combines mass and energy balance equations with neural networks that describe the process kinetics. Initially, an off-line training is performed in order to choose appropriate neural network architecture and in a second stage, the neural network parameters are re-estimated in an adaptive scheme that simulated changes in the microorganism kinetic behavior. The potential of a real-coded genetic algorithm and a binary-coded genetic algorithm to re-estimate the parameters of the neural network is evaluated. These algorithms were compared to the quasi-newton algorithm in terms of performance of the hybrid model. The results show that the proper choice of the neural network architecture and the use of an appropriate optimization algorithm results in a robust model, allowing further on-line optimization and control studies.

关键词： Genetic algorithms

来源：评论

学校读者我要写书评

暂无评论

control Strategies Evaluation for a Three-Phase Hydrogenation Catalytic Reactor

引用

IFAC Proceedings Volumes 2006年第2期39卷 427-432页

作者： Delba N.C. Melo Eduardo C. Vasco de Toledo Marcela M. Santos Rubens Maciel Filho Laboratory of Optimization Design and Advanced Control (LOPCA). Faculty of Chemical Engineering. State University of Campinas (Unicamp) P.O. Box 6066 13081-970 Campinas SP Brazil

Hydrogenation reactions are widely applied industrially, and reactors have been designed for this purpose. It is a highly non-linear process, multivariable, with exothermic reaction. The model formulation was made focusing on the hydrogenation reaction of o-cresol to obtain the 2-methil-cyclohexanol, in the presence of a Ni/SiO 2 catalyst. A competitive advantage in such kind of system (a commodity with large production scale) is to operate an optimal level of performance under control. The present work introduces an optimization problem and control in a simulation study of the reactor. The model allowed to reproduce the main characteristics of its dynamic, as well as the evaluation of the performance of different control strategies (Feedback, Feedforward or both strategies). The analysed controller was the linear model predictive (QDMC), and extensive analysis allow to identify which control strategy was more suitable to operate the reactor in an efficient and safe way. These informations are important for the real time integration implementation procedure.

关键词： hydrogenation dynamic modelling simulation optimization advanced controller

来源：评论

学校读者我要写书评

暂无评论

A KINETIC MATHEMATICAL MODEL OF KRAFT PULPING process FOR control AND optimization APPLICATIONS

引用

IFAC Proceedings Volumes 2006年第2期39卷 291-295页

作者： Natascha V. Polowski Eduardo C. Vasco de Toledo Rubens M. Filho Laboratory of Optimization Design and Advanced Control (LOPCA) Faculty of Chemical Engineering: State University of Campinas (Unicamp) P. O. Box 6066 13081-970 Campinas SP Brasil

Kraft wood pulping is the predominant process used in the pulp and paper industry for its versatility and insensitivity to variations of wood supply. In this work, a deterministic model has been developed for a Kraft Pulping process of Eucalyptus by combining intrinsic kinetic equations (Lignin, Carbohydrates) and it is used to investigate the effects of process conditions on the extent of delignification. The aim of this work is to develop a mathematical model which at some time is able to represent the main phenomena taking place in the process and suitable to be used in control and optimization applications.

关键词： Kraft pulping kinetic equation deterministic model and mass transfer equation

来源：评论

学校读者我要写书评

暂无评论

Procedure for development of a robust mathematical model for alcoholic fermentation process

Procedure for development of a robust mathematical model for...

引用

CHISA 2006 - 17th International Congress of Chemical and process Engineering

作者： De Andrade, Rafael Ramos Rivera, Elmer Ccopa Costa, Aline C. Atala, Daniel I. P. Maugeri, Francisco Filho, Rubens Maciel Laboratory of Optimization Design and Advanced Control School of Chemical Engineering State University of Campinas P.O. Box 6066 13081-970 Campinas SP Brazil Department of Food Engineering School of Food Engineering State University of Campinas P.O. Box 6121 13081-970 Campinas SP Brazil

ISBN: (纸本)8086059456

Among the main current problems related to industrial ethanol production is the lack of robustness of the fermentation in presence of fluctuations in the quality of raw material, which leads to changes in the kinetic behavior with impact on yield, productivity and conversion. This lack of robustness can be taken into account through operational and control adjustments, which can be aided by the use of an accurate mathematical model. In this work, a procedure to develop a robust mathematical model, valid in a large range of operational conditions, was established. This model considers the effect of temperature on the kinetics. Experiments were performed in batch mode. The microorganism used was Sacharomyces cerevisae and the culture media, sugar-cane molasses. The objective is to assess the difficulty in updating the kinetic parameters when there are changes in fermentation conditions. Yield and productivity were analyzed as functions of temperature and initial substrate concentration.

关键词： Yeast

来源：评论

学校读者我要写书评

暂无评论

APPLICATION OF GENETIC ALGORITHMS TO THE optimization OF AN INDUSTRIAL REACTOR

引用

IFAC Proceedings Volumes 2006年第2期39卷 857-862页

作者： Igor R de S. Victorino R Maciel Filho Laboratory of Optimization Design and Advanced Control (LOPCA). Faculty of Chemical Engineering. State University of Campinas (Unicamp) P.O. Box 6066 13081-970 Campinas SP Brazil Tel.:+55-19-37883971 Fax: +55-19-3788396

Genetic Algorithms (GAs) have shown great potential and ability to solve complex problems of optimization in diverse industrial fields, including chemical engineering process. In this paper, the main objective is to develop and implement a GA code in an industrial reactor of Cyclic Alcohol (CA) production for the optimization of operational parameters. The intention is to show that this technique is suitable for the maximization of Cyclic Alcohol production, obtaining good results with operational improvements (reduction of catalyst, reduction of the temperature of the process). The results show that the best performance of the process was achieved with the application of GAs. The developed procedure works very well in all the considered conditions which cover the most usual operating range for the considered process.

关键词： Global optimization Genetic algorithms Chemical process

来源：评论

学校读者我要写书评

暂无评论

Simulation of pulping process using neural networks and hybrid model 7th

Simulation of pulping process using neural networks and hybr...

引用

7th IFAC Symposium on Dynamics and control of process Systems, DYCOPS 2004

作者： Polowski, N.V. Aguiar, H.C. Maciel Filho, R. Laboratory of Optimization Design and Advanced Process Control Faculty of Chemical Engineering State University of Campinas P.O. 6066 Campus -SPZIP: 13081- 970 Brazil

A Neural Network Model is developed for a Kraft digester which is a fundamental stage in the pulp production. A deterministic model is used to describe the main features of the process and will provide the data to verify the performance of the artificial neural network modeling. The paper shows that the artificial neural network is a good way to represent the process since it gives equivalent results when compared to deterministic model, and it is easier and cheaper to be developed. © lhAC Dynamics and control of process Systems, Cambridge, Massachusetts, USA, 2004

关键词： Neural networks

来源：评论

学校读者我要写书评

暂无评论

Simulation of Pulping process Using Neural Networks and Hybrid Model

引用

IFAC Proceedings Volumes 2004年第9期37卷 691-696页

作者： N.V. Polowski H.C. Aguiar R. Maciel Filho Laboratory of Optimization Design and Advanced Process Control. Faculty of Chemical Engineering State University of Campinas P.O. 6066 – ZIP: 13081-970 – Campus – SP-Brazil

A Neural Network Model is developed for a Kraft digester which is a fundamental stage in the pulp production. A detenninistic model is used to describe the main features of the process and will provide the data to verify the performance of the artificial neural network modeling. The paper shows that the artificial neural network is a good way to represent the process since it gives equivalent results when compared to deterministic model, and it is easier and cheaper to be developed.

关键词： neural networks hybrid model pulp optimization

来源：评论

学校读者我要写书评

暂无评论

optimization strategy for maximizing production of cyclohexanol

引用

IFAC Proceedings Volumes 2004年第9期37卷 607-612页

作者： Delba N.C. Melo Eduardo C. Vasco de Toledo Salab D.M. Hasan Rubens M. Filho Laboratory of Optimization Design and Advanced Control (LOPCA). Faculty of Chemical Engineering. State University of Cam pin as (Unicamp) P.O. Box 6066 13081-970 Campinas SP Brazil Tel.:+55-19-37883971 Fax:+5 5-19-37883965

The main issue objective of this work is to implement an optimization strategy through a two-layer structure where the search for optimal operational variables is made through of the algorithms optimization - Successive quadratic programming - SQP. The considered process is based on the hydrogenation of phenol for production of cyclo-hexanol in the presence of a nickel catalyst. The objective function to be considered for the optimization is to maximize production of cyclo-hexanol, through a steady-state model while maintaining the conversion of phenol at the exit of the reactor under environmental constraints. Factorial design and response surface analysis in a simulation study of a three-phase catalytic slurry reactor is used to identify the impact that each variable has on the system as well as the interaction among then. An improvement of 5.5% in cyclo-hexanol conversion was observed for the optimized variables (O H = 259 kg/h, O Ni = 53 kg/h).The resulted model for the response surface was used as a flrst objective function for the SQP optimization. Theoptimization results can be then used as set-point values to the advanced controller

关键词： hydrogenation dynamics modeling response surface analysis optimization three-phase catalytic reactor integration of control and optimization algorithms simulation steady-state modeling

来源：评论

学校读者我要写书评

暂无评论

The development in infrared stereolithography using thermosensitive polymers

The development in infrared stereolithography using thermose...

引用

作者： Jardini, André L. Maciel, Rubens Scarparo, Marco A. Andrade, Suzimara R. Moura, Luiz F. Laboratory of Optimization Chemical Engineering Faculty State University of Campinas 13083-970 - Campinas - SP Brazil Design and Advanced Control Mechanical Engineering Faculty State University of Campinas 13083-970 - Campinas - SP Brazil

Infrared Laser Stereolithography is a novel method to produce three-dimensional plastic objects that allows the design of new ways to manufacture prototypes. In this experiment, the beam from an infrared laser (CO2) was focused onto a sample composed of epoxy resin, diethylene triamine, and silica powder. Data, using a differential scanning calorimetry (DSC), have also been reported demonstrating the curing rate as a function of temperature and activation energy of the curing process. A mathematical simulation, using a finite element method in the Ansys program, was applied to predict the cure profile of the resin as a function of laser radiation conditions, and showed good agreement with previous observations of the stereolithographic results. The results provide 3D solid structures with good spatial resolution and the final products showed no significant shrinkage. The stoichiometric amount and type of silica was found to be critical to confine the curing process to a localized volume.

关键词： Curing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：