Experiments and dynamic modeling of a reactive distillationcolumn for the production of ethyl acetate by consideringthe heterogeneous catalyst pilot complexities

Great effort has been applied to model and simulate the dynamic behavior of the reactive distillation as a successfulprocess intensification example. However, very little experimental work has been carried out in transient conditions.The work presents a series of experiments for the production of ethyl acetate from esterification of acetic acid andethanol in a reactive distillation pilot column. The steady-state approach performed experiments with both excessof alcohol and stoichiometric feed configuration. Predicted and measured results show good agreement and reveala strong dependency of the structured packing catalyst activity on the pilot geometry and its operating conditions.The transient process behavior of the heterogeneously catalyzed system was deeply investigated and continuousand dynamic data were collected for an equilibrium model validation, after different perturbations on parameters.The experimental validation is shown to be essential to provide realistic hydrodynamic parameters, to understandthe sensitive parameters such as heat losses and to adapt values for the catalyst holdup as a function of the system

Identifying multiple steady states in the design of reactive distillation processes

Global homotopy continuation is used to identify multiple steady states in ideal reactive flash and reactive distillation systems involving a reaction of the form A+B [symbol for \u3c--\u3e C taking place in the liquid phase. The choice of specifications has an influence on the existence of multiple solutions for both the flash and the column. For the flash, specification of the heat input or withdrawal can give rise to multiplicities while specification of the split fraction does not. Specification of one internal energy balance variable and one external material balance variable does not produce multiplicities in the column; however, specification of two internal energy balance variables can produce multiplicities. This is seen to have implications for the selection of control variables for both the flash and the column. The effects of the relative volatility between the light and heavy components, the forward rate constant, and the reaction equilibrium constant are studied. It is concluded that both the relative volatility spread and the equilibrium constant exhibit threshold values, below which only singular solutions are obtained. Above this threshold, multiplicities are to be found. The rate constant also affects the appearance of multiple solutions, but the multiplicities are found in regions bounded above and below by regions producing only singular solutions. The cause of multiplicities in the idealized system studied is seen to be the interaction between consumption and creation of species by reaction and transfer of material between phases. The reaction rate appears to be the major contributor to this effect because it is able to reverse direction, assuming either positive or negative values --Abstract, page iv

Implementation of a steady-state inversely controlled process model for integrated design and control of an ETBE reactive distillation

Recently, Sharifzadeh and Thornhill (2012) proposed a modeling approach for control structure selection using an inversely controlled process model, which benefits from significant complexity reductions. The treatment was based on the property that the inverse solution of a process model determines the best achievable control performance. The present article applies that methodology for integrated design and control of an ethyl tert-butyl ether (ETBE) reactive distillation column. In addition, the simulation-optimization program is reformulated using a penalty function, resulting in less optimization variables and better convergence of the simulation program. While the required computational efforts remain almost at the same level of steady-state process optimization, the process and its control structure are optimized simultaneously and regulatory steady-state operability of the solution is ensured. Finally, dynamic simulation is applied for detailed design of PI control loops

Mass Transfer in Multiphase Systems and its Applications

This book covers a number of developing topics in mass transfer processes in multiphase systems for a variety of applications. The book effectively blends theoretical, numerical, modeling and experimental aspects of mass transfer in multiphase systems that are usually encountered in many research areas such as chemical, reactor, environmental and petroleum engineering. From biological and chemical reactors to paper and wood industry and all the way to thin film, the 31 chapters of this book serve as an important reference for any researcher or engineer working in the field of mass transfer and related topics

Advanced Topics in Mass Transfer

This book introduces a number of selected advanced topics in mass transfer phenomenon and covers its theoretical, numerical, modeling and experimental aspects. The 26 chapters of this book are divided into five parts. The first is devoted to the study of some problems of mass transfer in microchannels, turbulence, waves and plasma, while chapters regarding mass transfer with hydro-, magnetohydro- and electro- dynamics are collected in the second part. The third part deals with mass transfer in food, such as rice, cheese, fruits and vegetables, and the fourth focuses on mass transfer in some large-scale applications such as geomorphologic studies. The last part introduces several issues of combined heat and mass transfer phenomena. The book can be considered as a rich reference for researchers and engineers working in the field of mass transfer and its related topics

Book of abstracts of the 10th International Chemical and Biological Engineering Conference: CHEMPOR 2008

This book contains the extended abstracts presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, over 3 days, from the 4th to the 6th of September, 2008. Previous editions took place in Lisboa (1975, 1889, 1998), Braga (1978), Póvoa de Varzim (1981), Coimbra (1985, 2005), Porto (1993), and Aveiro (2001). The conference was jointly organized by the University of Minho, “Ordem dos Engenheiros”, and the IBB - Institute for Biotechnology and Bioengineering with the usual support of the “Sociedade Portuguesa de Química” and, by the first time, of the “Sociedade Portuguesa de Biotecnologia”. Thirty years elapsed since CHEMPOR was held at the University of Minho, organized by T.R. Bott, D. Allen, A. Bridgwater, J.J.B. Romero, L.J.S. Soares and J.D.R.S. Pinheiro. We are fortunate to have Profs. Bott, Soares and Pinheiro in the Honor Committee of this 10th edition, under the high Patronage of his Excellency the President of the Portuguese Republic, Prof. Aníbal Cavaco Silva. The opening ceremony will confer Prof. Bott with a “Long Term Achievement” award acknowledging the important contribution Prof. Bott brought along more than 30 years to the development of the Chemical Engineering science, to the launch of CHEMPOR series and specially to the University of Minho. Prof. Bott’s inaugural lecture will address the importance of effective energy management in processing operations, particularly in the effectiveness of heat recovery and the associated reduction in greenhouse gas emission from combustion processes. The CHEMPOR series traditionally brings together both young and established researchers and end users to discuss recent developments in different areas of Chemical Engineering. The scope of this edition is broadening out by including the Biological Engineering research. One of the major core areas of the conference program is life quality, due to the importance that Chemical and Biological Engineering plays in this area. “Integration of Life Sciences & Engineering” and “Sustainable Process-Product Development through Green Chemistry” are two of the leading themes with papers addressing such important issues. This is complemented with additional leading themes including “Advancing the Chemical and Biological Engineering Fundamentals”, “Multi-Scale and/or Multi-Disciplinary Approach to Process-Product Innovation”, “Systematic Methods and Tools for Managing the Complexity”, and “Educating Chemical and Biological Engineers for Coming Challenges” which define the extended abstracts arrangements along this book. A total of 516 extended abstracts are included in the book, consisting of 7 invited lecturers, 15 keynote, 105 short oral presentations given in 5 parallel sessions, along with 6 slots for viewing 389 poster presentations. Full papers are jointly included in the companion Proceedings in CD-ROM. All papers have been reviewed and we are grateful to the members of scientific and organizing committees for their evaluations. It was an intensive task since 610 submitted abstracts from 45 countries were received. It has been an honor for us to contribute to setting up CHEMPOR 2008 during almost two years. We wish to thank the authors who have contributed to yield a high scientific standard to the program. We are thankful to the sponsors who have contributed decisively to this event. We also extend our gratefulness to all those who, through their dedicated efforts, have assisted us in this task. On behalf of the Scientific and Organizing Committees we wish you that together with an interesting reading, the scientific program and the social moments organized will be memorable for all.Fundação para a Ciência e a Tecnologia (FCT

Polymorph selection in continuous, reactive, rate-based, precipitation systems

Many materials are capable of organizing into multiple distinct solid phases, each exhibiting a unique set of material properties (e.g., mechanical, optical, electronic, catalytic, etc.). This material property diversity implies that a specific solid form or structure is typically preferred for a specific application. Thus, directing and controlling solid form during crystallization processes is a fundamental solid state engineering challenge. Here, for the first time, a general procedure is presented for designing continuous crystallizers that produce polymorphically pure crystal distributions of a preferred polymorph regardless of that polymorph's relative thermodynamic stability. The design rules were generated by developing and analyzing a multi-polymorph mixed suspension mixed product removal precipitator model, and they have been corroborated both by experimental data generated in our lab and by all of the applicable data in the published literature. These rules were developed to build understanding and aid in the process design of two sustainable energy technologies: carbon capture and utilization as structural materials (CCUSM) and methane pyrolysis (MP). Studying these processes also required the development of new models for calculating interphase mass transport in concentrated, electrolytic, reacting solutions and for describing the reactive transport that occurs in methane pyrolysis membrane reactors. The development and analysis of these models and a thermodynamic minimum energetic cost assessment of a wider set of sustainable energy technologies are also included in the dissertation