Chemical Engineering Practice Research Articles

A Mixed Coding Scheme of a Particle Swarm Optimization and a Hybrid Genetic Algorithm with Sequential Quadratic Programming for Mixed Integer Nonlinear Programming in Common Chemical Engineering Practice

In this paper, mixed integer nonlinear programming (MINLP) is optimized by PSO_GA–SQP, the mixed coding of a particle swarm optimization (PSO), and a hybrid genetic algorithm and sequential quadratic programming (GA–SQP). The population is separated into two groups: discrete and continuous variables. The discrete variables are optimized by the adapted PSO, while the continuous variables are optimized by the GA–SQP using the discrete variable information from the adapted PSO. Therefore, the population can be set to a smaller size than usual to obtain a global solution. The proposed PSO_GA–SQP algorithm is verified using various MINLP problems including the designing of retrofit heat exchanger networks. The fitness values of the tested problems are able to reach the global optimum.

Linear model predictive control for transport‐reaction processes

The article deals with systematic development of linear model predictive control algorithms for linear transport‐reaction models emerging from chemical engineering practice. The finite‐horizon constrained optimal control problems are addressed for the systems varying from the convection dominated models described by hyperbolic partial differential equations (PDEs) to the diffusion models described by parabolic PDEs. The novelty of the design procedure lies in the fact that spatial discretization and/or any other type of spatial approximation of the process model plant is not considered and the system is completely captured with the proposed Cayley‐Tustin transformation, which maps a plant model from a continuous to a discrete state space setting. The issues of optimality and constrained stabilization are addressed within the controller design setting leading to the finite constrained quadratic regulator problem, which is easily realized and is no more computationally intensive than the existing algorithms. The methodology is demonstrated for examples of hyperbolic/parabolic PDEs. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2644–2659, 2017

Product engineering and sustainability

Chemical engineering has made a substantial contribution to the improvement of the environment during the last decades. Many processes have become more sustainable and harmful waste streams are minimised. However, considerable improvement of sustainability can still be obtained in product engineering and design. Especially the aspects that are important at the end of the life cycle of the product can be improved considerably. A priority list for the design of more sustainable products is presented and illustrated with examples of daily chemical engineering practice.

Research on data reconciliation based on generalized T distribution with historical data

In the most of previous data reconciliation(DR) studies, process data were conventionally characterized by normal Gaussian distribution, so the optimality/validity of DR estimator is implicitly based on a main assumption that errors follow normal Gaussian distribution. When this assumption is not satisfied, conventional data reconciliation approaches will become unavailable. However, normal distribution usually does not exist in real chemical engineering practice, as it is hard to ensure the normality even for high-quality measurements. So it is necessary to propose a new DR method which can accommodate more variety of measurement error distribution. In this paper, generalized T distribution is applied to accommodate measurement error distribution, meanwhile, historical data is introduced to estimate the objective function parameters by using Particle Swarm Optimization (PSO) algorithm. A novel robust data reconciliation method is proposed based on GT distribution and historical data, at the same time, its robustness characteristics are investigated. The new method is demonstrated on a steam-metering system for a methanol synthesis unit. Based on the comparison with other DR methods, the novel robust DR method can effectively improve the reliability of reconciled data even when errors do not follow normal distribution.

Principles of Chemical Engineering Practice. Von G. DeLancey

Principles of Chemical Engineering Practice. Von G. DeLancey

A new methodology of autonomous learning aplied to a Chemical Engineering practice through research- action techniques

Un grupo de profesores del Departamento de Ingenieria Quimica y Ambiental de la Escuela Tecnica Superior de Ingenieria de la Universidad de Sevilla ha realizado un trabajo de investigacion-accion con el objetivo de mejorar los resultados docentes en la asignatura Experimentacion en Ingenieria Quimica. El proceso de investigacion-accion ha consistido en disenar una metodologia alternativa para una de las practicas de la asignatura, incorporando un ejercicio de auto-aprendizaje que sustituya a la tradicional metodologia aplicada. El objetivo de la experiencia docente pretende conseguir una participacion mas activa del alumnado, mejorando la asimilacion de conceptos y la capacidad para planear el trabajo experimental. Los resultados obtenidos con la nueva metodologia, comparados con los del metodo tradicional de la experiencia, indican que, aunque los alumnos tienden a adoptar una actitud pasiva y son reacios a aumentar el grado de trabajo autonomo, el nuevo procedimiento ayudo a mejorar la aplicacion de los conceptos teoricos en el diseno y la realizacion de la practica.

The Neal Amundson era. Rapid evolution of chemical engineering science

Neal Amundson (1916–2011) influenced the chemical engineering profession more profoundly than any other single individual, and in this article the author has attempted to capture the man and his era, as well as his lasting legacy. His influence extended well beyond those of other chemical engineers of renown, whether they were known for exploring and establishing new avenues, or for the resolution of outstanding issues, or for other forms of creative endeavors. Amundson reached into the depths of the profession, noted for its expanse, complexity and diversity that had led earlier efforts into a shrine of empiricism, to foster a culture of strongly scientific thinking with a mathematical edifice, which must be the crux of all engineering. The growth of chemical engineering science owes most significantly to Amundson's extraordinary role as an educator, department head and leader, and to the lasting impact of his contributions to chemical engineering research and practice. This article is in salutation of the man who came to be known as the Minnesota Chief, and was responsible for an academic movement that raised the intellectual level of the chemical engineering profession. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3147–3157, 2013

LabVIEW based e-learning portal for virtual mass transfer operations laboratory

This article, introduces the unique concept of virtual mass transfer laboratory, an exercise that has been developed by IIT Guwahati under the auspices of Ministry of Human Resource and Development (MHRD) under National Mission on Education through ICT. The virtual mass transfer laboratory constitutes eight distinct virtual laboratory modules that cover various aspects of mass transfer operations, a key subject in chemical engineering education and practice. While all modules are simulation based, in addition to the most essential virtual lab simulator, the virtual laboratory modules essentially include all aspects of virtual laboratory education namely theory, experimental procedure, animation, quizzes etc. The virtual laboratory environment enabled an improved learning of chemical engineering, as learning is often better achieved by practice and repeated experimentation/observation in real world scenarios. Further, field trails and user friendly workshops have also been organized to obtain real time feedback and these have been extremely beneficial to improve the quality of the technical content as well as e-learning in the virtual mass transfer laboratories. Thereby a framework to explore possibilities to further creative component in chemical engineering has been developed.

Chemical Engineering Education and Practice in Bangladesh

Chemical Engineering as a distinct engineering discipline is now more than hundred years old. It was 1888 when Professor Louis Mills Norton first introduced the curricula for Chemical Engineering at MIT. As creative chemists came up with new chemicals it provided ever new challenges to the Chemical Engineers to innovate new industrial processes applying the new found knowledge in unit operations, unit processes, reaction engineering, process control, (later) transport phenomena and (recently) process integration. In Bangladesh the founding fathers of engineering education took a long term view of the industrial development prospects and took the innovative decision to introduce Chemical Engineering curricula in the erstwhile Ahsanullah Engineering College in the early fifties. During these early years large corporations in the public sector provided the initial thrust for development of chemical and process industries. However it was not adequately appreciated during the formative years that mere experience in the successful operation of complex chemical plants does not constitute technology transfer in the real sense of the term. Professional in the field stressed the need for setting up of design sections where local chemical engineers with inputs form relevant professionals would be able to contribute meaningfully in establishing the design criteria for a plant. In the private sector Chemical Engineers have demonstrated in Bangladesh that they can be innovative in transferring technology and developing Ceramic and medium scale Basic Chemical industries. Thus, it has been amply demonstrated that accumulating technological capacity through such dynamic technology transfer efforts should be one of the avowed objectives of any development process. Professional Capability and Areas of Competence of Chemical Engineers have grown over the years in this country and this issue has been elaborated with specific examples.DOI: http://dx.doi.org/10.3329/jce.v26i1.10174 JCE 2011; 26(1): 1-8

Fluid mechanics, heat transfer, and mass transfer: chemical engineering practice

Fluid mechanics, heat transfer, and mass transfer: chemical engineering practice

New insight into internal model control filter design for load disturbance rejection

In this study, a modified design of the internal model control (IMC) filter is proposed for improving closed-loop system performance of load disturbance rejection, especially for slow processes in industrial and chemical engineering practices. The deficiency of a conventional IMC filter design for controller tuning is revealed with regard to load disturbance rejection. By constructing one or more asymptotic canceling constraints for disturbance rejection, a modified IMC filter is proposed to reduce the influence from the time constant(s) of the process or repetitive-type load disturbance to the closed-loop disturbance rejection performance. Similar to a conventional IMC filter, there is essentially a single adjustable parameter in the proposed IMC filter, which can be monotonically tuned to meet with the compromise between the achievable disturbance rejection performance and the closed-loop system stability. Quantitative tuning formulae and guidelines for this adjustable parameter are developed in terms of the widely used first- and second-order process models with time delay. Illustrative examples are given to show the effectiveness and merits of the proposed IMC filter.

Physiologically Based Pharmacokinetics: A Simple, All Purpose Model

Physiologically Based Pharmacokinetics: A Simple, All Purpose Model

Integration of process design and controller design for chemical processes using model-based methodology

In this paper, a novel systematic model-based methodology for performing integrated process design and controller design ( IPDC) for chemical processes is presented. The methodology uses a decomposition method to solve the IPDC typically formulated as a mathematical programming (optimization with constraints) problem. Accordingly the optimization problem is decomposed into four sub-problems: (i) pre-analysis, (ii) design analysis, (iii) controller design analysis, and (iv) final selection and verification, which are relatively easier to solve. The methodology makes use of thermodynamic-process insights and the reverse design approach to arrive at the final process design–controller design decisions. The developed methodology is illustrated through the design of: (a) a single reactor, (b) a single separator, and (c) a reactor–separator-recycle system and shown to provide effective solutions that satisfy design, control and cost criteria. The advantage of the proposed methodology is that it is systematic, makes use of thermodynamic-process knowledge and provides valuable insights to the solution of IPDC problems in chemical engineering practice.

Computation of an extractive distillation column with affine arithmetic

The need of reliably solving systems of nonlinear equations often arises in the everyday practice of chemical engineering. In general, standard methods cannot provide theoretical guarantee for convergence to a solution, cannot reliably find multiple solutions, and cannot prove nonexistence of solutions. Interval methods provide tools to overcome these problems, thus achieving reliability. To the authors' best knowledge, computation of distillation columns with interval methods have not yet been considered in the literature. This article presents significant enhancements compared with a previously published interval method of the authors. The proposed branch-and-prune algorithm is guaranteed to converge, and is fairly general at the same time. If no solution exists then this information is provided by the method as a result. Power of the suggested method is demonstrated by solving, with guaranteed convergence, even the MESH equations of a 22 stage extractive distillation column with a ternary mixture. © 2009 American Institute of Chemical Engineers AIChE J, 2009

A history of process safety and loss prevention in the American Institute of Chemical Engineers

AbstractProcess safety has always been an important consideration in chemical engineering, and the activities of the American Institute of Chemical Engineers (AIChE) have expanded over the years to more formally focus on this critical aspect of chemical engineering practice. Early initiatives included the annual symposia on Safety in Ammonia and Related Plants, dating back to the early 1950s, and the Loss Prevention Symposium, first held in 1967. These activities led to the formation of the AIChE's Safety and Health Division in 1979, and the division assumed responsibility for these existing programming activities. Following the Bhopal tragedy in India, AIChE formed the Center for Chemical Process Safety (CCPS) in 1985 as an industry alliance to share and enhance process safety expertise in the industry. One of the early CCPS activities was the creation of the Safety and Chemical Engineering Education (SACHE) program to enhance teaching of process safety in the university chemical engineering curriculum. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009

Chemical Engineering Design Principles, Practice, and Economics of Plant and Process Design By G. Towler and R. Sinnott

<i>Chemical Engineering Design Principles, Practice, and Economics of Plant and Process Design</i> By G. Towler and R. Sinnott

Differential Evolution with Tabu List for Solving Nonlinear and Mixed-Integer Nonlinear Programming Problems

Differential evolution (DE), a population-based direct-search algorithm, has been gaining popularity in the recent past due to its simplicity and ability to handle nonlinear, nondifferentiable, and nonconvex functions. In this study, a method, namely, differential evolution with tabu list (DETL), is described and evaluated for solving constrained optimization problems encountered in chemical engineering. It incorporates the concept of tabu search (TS) (i.e., avoiding revisits during the search) in DE mainly to improve its computational efficiency. DETL is initially applied to many nonlinear programming problems (NLPs) involving 2−13 variables and up to 38 constraints. It is then tested on several mixed-integer nonlinear programming problems (MINLPs) encountered in chemical engineering practice. The performance results of DETL, DE, and modified differential evolution (MDE) (Babu, K. V.; Angira, R. Comput. Chem. Eng. 2006, 30, 989), for both NLPs and MINLPs, are presented, and the relative performance of the three methods is discussed.

Optimization of reactive distillation processes using differential evolution strategies

AbstractMany problems of process synthesis and design in chemical engineering can be modeled as mixed integer nonlinear programming (MINLP) problems. They include both the continuous (floating point) and integer variables. A common feature of this class of mathematical problems is the potential existence of nonconvexities due to a particular form of the objective function and/or the set of constraints. Owing to their combinatorial nature, these problems are considered to be difficult to solve. In the present study, a model based on an extension of conventional distillation is proposed for the synthesis of ethylene glycol using the nonequilibrium reactive distillation. The proposed model is simulated using the relaxation and homotopy‐continuation methods. The differential evolution (DE) algorithm is applied to find the minimum total annualized cost of the nonequilibrium reactive distillation for the synthesis of ethylene glycol, which is a MINLP optimization problem.The optimization is performed with nonideal vapor–liquid equilibrium using ten strategies of DE, considering synthesis reaction on all trays. The results show that the optimized objective function values are better than those reported in the literature, and mostly independent of the number of trays and of the reaction distribution. It is shown that the proposed homotopy‐continuation method with DE strategy (DE/best/1/bin) is capable of providing optimized solutions which are close to the global optimum, and reveals its adequacy for the optimization of reactive distillation problems encountered in chemical engineering practice. Copyright © 2007 Curtin University of Technology and John Wiley &amp; Sons, Ltd.

PROCESS CONTROL PERSPECTIVE FOR PROCESS ANALYTICAL TECHNOLOGY: INTEGRATION OF CHEMICAL ENGINEERING PRACTICE INTO SEMICONDUCTOR AND PHARMACEUTICAL INDUSTRIES

FDA's Process Analytical Technology (PAT) initiative provides an unprecedented opportunity for chemical engineers to play significant roles in the pharmaceutical industry. In this article, the authors provide their perspectives on (1) the need for chemical engineering principles in pharmaceutical development for a thorough process understanding; (2) applications of chemical engineering principles to meet the challenges from the semiconductor and pharmaceutical industries; and (3) the integration of chemical engineering practice into the semiconductor and pharmaceutical industries to achieve process understanding and the desired state of quality-by-design. A real-world case study from the semiconductor industry is presented to demonstrate how a classic chemical engineering concept, mixing homogeneity, can be implemented by inducing forced flow to ensure an excellent copper electrochemical plating process performance and to improve product quality substantially. Further, a case study of brake system design is discussed with the concept of Dr. Taguchi's robust engineering design to illustrate how quality-by-design can be achieved through appropriate experimental design, in conjunction with the discussion on the concept of quality-by-design in pharmaceuticals. Third, a case study of freeze-dried sodium ethacrynate is presented to demonstrate the vital importance of controlling the processing factors to achieve the desired product stability. Finally, the problems of the current pharmaceutical manufacturing mode, the opportunities and engineering challenges during implementation of PAT in the pharmaceutical industry, and the role of chemical engineering in implementation of PAT is discussed in detail.

Process Simulation - From Large Computers and Small Solutions to Small Computers and Large Solutions

This paper reviews the evolution of process simulation in conjunction with the evolution of computer hardware and software technologies from a chemical engineering perspective. A brief history of this hardware evolution is presented and points to exponential growth of computing power. The current personal computers or full function workstations have at least 1GB of memory, 100GB hard drive and run at 4 GHz. We as chemical engineers can only benefit from this continued hardware evolution, as the personal computer has become our full function slide rule.Concurrent with this hardware evolution there has been a proliferation of operating systems and applications software. Some of the applications software has migrated from mainframes and minicomputers and some has been specifically written to take advantage of the user-friendly features available on today's personal computers. A review of this software is presented with particular emphasis on process simulation software. The currently available fifth generation, non-sequential interactive process simulator does make process modeling and design a truly rewarding experience. This software has been designed to allow the personal computer and the engineer to do what each does best, namely the personal computer performing the systematic number crunching and the engineer the intuitive aspect of process simulation and design. The paper will conclude with a look into the future development of process simulation and its interaction with chemical engineering practice.