Dynamic Modeling of a Reactive Distillation Column


Book Description

This research focuses on white box modeling of the dynamics of a reactive distillation column, precisely, one that is used for the commercial production of MTBE (methyl-tert-butyl-ether) by the reaction between methanol and isobutylene. The motivation for this study is mainly the process complexity posed by simultaneous reaction and separation which complicates the design and control of the column. In this study, an equilibrium model of reactive distillation column is developed in MATLAB by putting together the MESH equations and other equations like Francis weir formula and reaction rate law. Subsequently, the developed model is validated by comparison of simulation results with industrial data. Finally, the dynamic behaviour of the system is studied by applying step changes to each of the input variables, one at a time. The model of reactive distillation column is successfully developed. It is also proven to be a good representation of the column in the industry because model predictions and plant data come to a good agreement.




Reactive Batch Distillation of Ethyl Acetate


Book Description

Reactive distillation is a multi-functional unit operation combining chemical reactor and distillation column in a single unit. Fatty acid esterification is increasingly realized as a reactive distillation (RD) process because of its formation being affected by the chemical equilibrium. In this work, a detailed mathematical dynamic rate-based model of reactive batch distillation column is formulated for ethyl acetate synthesis and presented as a system of differential and algebraic equations (DAEs). The developed model is then solved to obtain the detailed column dynamics. The simulation results provide the dynamics of reboiler and distillate compositions, ethyl acetate purity in the accumulated distillate and conversion of the reactants. These simulation results are compared with experimental data, and it indicates a very good agreement. The developed model is then applied to formulate dynamic optimization problem in order to derive the optimum operating policy, reflux profile.




Reactive Distillation Design and Control


Book Description

After an overview of the fundamentals, limitations, and scope of reactive distillation, this book uses rigorous models for steady-state design and dynamic analysis of different types of reactive distillation columns and quantitatively compares the economics of reactive distillation columns with conventional multi-unit processes. It goes beyond traditional steady-state design that primarily considers the capital investment and energy costs when analyzing the control structure and the dynamic robustness of disturbances, and discusses how to maximize the economic and environmental benefits of reactive distillation technology.




Distillation Design and Control Using Aspen Simulation


Book Description

Learn how to develop optimal steady-state designs for distillation systems As the search for new energy sources grows ever more urgent, distillation remains at the forefront among separation methods in the chemical, petroleum, and energy industries. Most importantly, as renewable sources of energy and chemical feedstocks continue to be developed, distillation design and control will become ever more important in our ability to ensure global sustainability. Using the commercial simulators Aspen Plus® and Aspen Dynamics®, this text enables readers to develop optimal steady-state designs for distillation systems. Moreover, readers will discover how to develop effective control structures. While traditional distillation texts focus on the steady-state economic aspects of distillation design, this text also addresses such issues as dynamic performance in the face of disturbances. Distillation Design and Control Using Aspen Simulation introduces the current status and future implications of this vital technology from the perspectives of steady-state design and dynamics. The book begins with a discussion of vapor-liquid phase equilibrium and then explains the core methods and approaches for analyzing distillation columns. Next, the author covers such topics as: Setting up a steady-state simulation Distillation economic optimization Steady-state calculations for control structure selection Control of petroleum fractionators Design and control of divided-wall columns Pressure-compensated temperature control in distillation columns Synthesizing four decades of research breakthroughs and practical applications in this dynamic field, Distillation Design and Control Using Aspen Simulation is a trusted reference that enables both students and experienced engineers to solve a broad range of challenging distillation problems.




Modeling and Simulation of Distillation Column


Book Description

This paper presents modeling and simulation studies of distillation column. This study is to stimulate sieve tray distillation (rate based model) and specifically for multiple columns process by using Aspen Hysys. The economic importance of distillation separations has been a driving force for the research in synthesis procedures for more than 30 years. Distillation accounts for almost 90% of the separation systems used in chemical process industries. The best way to reduce operating costs of existing units is to improve their efficiency and operation via process optimization and control. Simulation generates one or more trajectories (possible behaviors from the high-level model), and collects statistics from these trajectories to estimate the desired performance or dependability measures. Modeling and simulation of distillation column might already be very familiar but modeling and simulation of multicomponent distillation in multiple columns still yet being commercially introduced to the industries. In this project, the well known kind of multi components (n-butane, n-pentane and benzene) is chosen as the example to run this simulation by using multiple distillation columns. By inserting the details and specifications in Aspen Hysys, multicomponents distillation process is stimulated under steady state condition. From the result gained, calculations such as compositions, temperature, mass balance and energy balance can be done step by step. The composition, k values, temperature and flowrate will be further explained in discussion. Other than that, the limitations of steady state techniques are discussed, and the need for rigorous dynamic simulation for final selection of a workable and robust strategy is illustrated.




Development of Dynamic Models of Reactive Distillation Columns for Simulation and Determination of Control


Book Description

Dynamic models of a reactive distillation column have been developed and implemented in this work. A model describing the steady state behavior of the system has been built in a first step. The results from this steady state model have been compared to data provided from an industrial collaborator and the reconciled model formed the basis for the development of a dynamic model. Four controlled and four manipulated variables have been determined in a subsequent step and step tests for the manipulated variables were simulated. The data generated by the step responses was used for fitting transfer functions between the manipulated and the controlled variables. RGA analysis was performed to find the optimal pairing for controller design. Feedback controllers of PID type were designed between the paired variables found from RGA and the controllers were implemented on the column model. Both servo and regulatory problems have been considered and tested.




Distillation Design


Book Description

Providing coverage of design principles for distillation processes, this text contains a presentation of process and equipment design procedures. It also highlights limitations of some design methods, and offers guidance on how to overcome them.







Distillation


Book Description

The purpose of this book is to offer readers important topics on the modeling, simulation, and optimization of distillation processes. The book is divided into four main sections: the first section is introduction to the topic, the second presents work related to distillation process modeling, the third deals with the modeling of phase equilibrium, one of the most important steps of distillation process modeling, and the the fourth looks at the reactive distillation process, a process that has been applied successfully to a number of applications and has been revealed as a promising strategy for a number of recent challenges.