UNIVERSITY OF CALGARY Process Design and Control for Eco-Efficiency by Juan Manuel Montelongo Luna A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMICAL AND PETROLEUM ENGINEERING CALGARY, ALBERTA MAY, 2010 © Juan M Montelongo-Luna 2010 Library and Archives Bibliothèque et Canada Archives Canada Published Heritage Direction du Branch Patrimoine de l’édition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre référence ISBN: 978-0-494-69529-6 Our file Notre référence ISBN: 978-0-494-69529-6 NOTICE: AVIS: The author has granted a non- L’auteur a accordé une licence non exclusive exclusive license allowing Library and permettant à la Bibliothèque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par télécommunication ou par l’Internet, prêter, telecommunication or on the Internet, distribuer et vendre des thèses partout dans le loan, distribute and sell theses monde, à des fins commerciales ou autres, sur worldwide, for commercial or non- support microforme, papier, électronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. 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UNIVERSITY OF CALGARY FACULTY OF GRADUATE STUDIES The undersigned certify that they have read, and recommend to the Faculty of Graduate Studies for acceptance, a thesis entitled "Process Design and Control for Eco-Efficiency" submitted by Juan Manuel Montelongo Luna in partial fulfilment of the requirements of the degree of Doctor of Philosophy. Supervisor, Dr. William Y. Svrcek, Chemical and Petroleum Engineering Co-Supervisor, Dr. Brent R. Young, Chemical and Materials Engineering, University of Auckland Dr. Abdulmajeed Mohamad, Mechanical and Manufacturing Engineering Dr. Wayne D. Monnery, Chemical and Petroleum Engineering Dr. Harvey Yarranton, Chemical and Petroleum Engineering Dr. Om P. Malik, Electrical and Computer Engineering External Examiner, Dr. Paul Stuart, École Polytechnique de Montréal Date ii Abstract The main objective of process design is to develop processes or plants that will produce goods of higher value than the raw materials used. Consequently, process design is mostly driven by the economics of production. However, many other factors, such as operability and environmental regulations have to be considered in the design of a process. Due to the dynamic nature of chemical and petrochemical processes, without process control a plant could not be operated safely and at design conditions. Disturbances drive the process in directions that are not the desired/designed operating levels. Process control is the means by which disturbances are rejected. Exergy can be derived from the application of the first and the second laws of thermodynamics to a process. Exergy can be used as a measurement of how valuable the process is, that is, if the exergy values of the products of the process are close to those of the raw materials the process is highly (thermodynamically) efficient. An eco-efficient process can be defined as one that is ecologically friendly and economically viable. This means the process should reduce energy consumption (or exergy destruction), which in turn reduces operating expenses. Exergy along with an integrated framework for process design and process control can be used to develop more efficient processes in a faster and less costly manner than conventional process design. The objectives of this research project were to develop an exergy calculator for chemical process streams and to develop a controllability index based on exergy. These tools will allow the design engineer to gain insight into the eco-efficiency of the process iii from the early design stages and will reduce the number of design and control structure alternatives that need to be evaluated in detail. The Exergy Calculator was developed and implemented in a commercial process simulator (HYSYS®) and in an open source chemical process simulator (Sim42®). This tool facilitates the generation of an exergy analysis for any process for which a simulation exists. The new Relative Exergy Array (REA) is a controllability index that, when used with the RGA, provides information about the process interactions of a control structure and its relative thermodynamic efficiency. iv Acknowledgements Six years may seem like a lot of time but they surely have passed very fast. During this time I had the honour and pleasure of having wonderful people around me from which I have learned many things about chemical engineering and about life. I will always be in debt to my supervisor and friend Dr. William Y. Svrcek. It is very hard to find words to express my gratitude to you Bill. Thank you for all the support and encouragement so I could complete this thesis. I learned many things from you and from the side projects you trusted me and I am sure I can still learn more. Thank you for all the cups of coffee and the occasional “chat and walk” sessions through the university’s campus. I deeply appreciate the help, support and encouragement from my co-supervisor and friend Dr. Brent R. Young. Although separated by almost 12000 km during the last three years of this research project, Brent has never stopped guiding me through the tortuous paths of process control. Thank you for trusting in me when I first arrived to Calgary. I also want to thank you and your family for hosting me during my trip to New Zealand. I would like to acknowledge the financial support from the Alberta Energy Research Institute (AERI) through its COURSE program. The financial support from the Chemical and Petroleum Engineering Department is also greatly appreciated. I would like to thank the administrative staff at the Chemical and Petroleum Engineering Department, particularly to Ms. Andrea Cortes and Ms. Arlene Wallwork, for all their help. v Undoubtedly, the encouragement from many friends helped me continue and cheered me up when I most needed it. Special thanks to Mr. Raul Cota for all his help with Sim42 and for his friendship and the support he has continuously given me since we met in Mexico during our undergraduate studies. I am particularly thankful to Mr. Mahyar Mohajer whom always was there for me whenever I needed to discuss process control, process simulation or just to grab a cup of coffee. Mahyar you are a true friend and I am lucky to have met you. I would have never been able to finish this thesis without the support and encouragement of Miss Maryam Rajayi. Thank you for believing in me and for staying up late at night with me while I was writing this thesis. I promise you won’t hear the word “thesis” from me anymore. I love you. Last but certainly not least I am eternally grateful to my parents, Argelia and Juan, and to my sister, Isadora, for all the love and support they have given me throughout my life and especially during these last six years. Thank you for never giving up on me and for encouraging me to continue the pursuit of my dream... I love you. vi Dedication To my parents, Maria B. Argelia Luna and Juan M Montelongo. vii Table of Contents Approval Page ..................................................................................................................... ii Abstract .............................................................................................................................. iii Acknowledgements ..............................................................................................................v Dedication ......................................................................................................................... vii Table of Contents ............................................................................................................. viii List of Tables ..................................................................................................................... xi List of Figures and Illustrations ........................................................................................ xii List of Symbols, Abbreviations and Nomenclature ......................................................... xiii CHAPTER ONE: INTRODUCTION ..................................................................................1 1.1 Process Design ...........................................................................................................2 1.2 Process Control ..........................................................................................................4