Evaluation of different cleaning agents used for cleaning ultra tiltration membranes fouled by surface water.

Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractIn order to investigate the feasibility of constrained multivariable control of a heat-integrated cryogenic distillation process, a rigorous first principles dynamic model was developed and tested against a limited number of experiments. It was found that the process variables showed a large amount of interaction, which is responsible for the difficulties with the presently used, PID-based, control scheme, especially in load-following situations, which are common in air separation plants such as for instance integrated coal gasification combined cycle plants. Contrary to what is suggested in the literature, it was found that vapor hold-up in low-temperature, high-pressure columns does not play a significant role in the process dynamics. Despite large throughput changes and non-linear process behavior, multivariable model predictive control using a linearized model for average operating conditions, could work well provided all process flows have sufficient range. Due to the strong interactive nature of the process variables, process changes have to be made slowly, since otherwise manipulated variables easily saturate and process output targets cannot be maintained.

An operating model for dead-end membrane filtration is proposed based on the well-known blocking laws. The resulting model contains three parameters representing, the operating strategy, the fouling mechanism and the fouling potential of the feed. The optimal control strategy is determined by minimizing the energy consumption for a fixed final time and produced volume. It was found that constant power filtration leads to minimal energy consumption. Constant flux and constant pressure filtration have equal energy costs. However, compared to strategies with a non-decreasing pressure and non-increasing flux, the relative savings are small. Only if the fouling mechanism resembles standard blocking and the fouling resistance is large compared to the membrane resistance, it may be attractive to implement the optimal trajectory.

Hydrogen Response in Liquid Propylene PolymerizationAl-haj Ali, M.; Betlem, B.; Roffel, B.; Weickert, G. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum.

Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

The use of general descriptive names , registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.Typesetting: Camera ready by authors Cover-design: medio, Berlin Printed on acid-free paper 62/3020 hu -5 43 2 1 0 - PrefaceIn the process industries there is an ongoing need for improvement of the operation of the process . One of the disciplines that will help the process engineer to achieve this is process control. There are many industrial automation systems today that will offer powerful tools to meet the process control needs of industries with continuous, batch and discrete operations. Advanced control solutions sustain and improve the plant's competitiveness by ensuring:-safe operations -compliance with environmental regulations -effective use of raw materials and energy -efficient production -manufacturing of high quality products -flexible accommodation of changing process requirements This book was written from the perspective of introducing advanced control concepts, which can help the engineer to reach the aforementioned goals . Many advanced control techniques have been implemented in industry in recent years, since hardware and software platforms are becoming increasingly powerful. Manufacturers of process control equipment call this hardware and software environment generally 'distributed control system' . The distributed control system equipment offers the engineer an excellent platform for writing and implementing advanced control solutions. However, most large chemical and petrochemical manufacturers hire control specialists to implement these control solutions, while small manufacturers often lack the funds to hire these professionals. Therefore it is our experience that in the latter case, process engineers often write the control programs required to improve process operation.However, the step from textbook or theory to control implementation is a major one. Simulation can help the engineer to increase his or her understanding of the problem and enables him or her to first check whether the proposed solution indeed solves the problem.This book is set up to help the engineer and student to start from the available theory and build control solutions. The focus of the book is not on process dynamics but on process control and process optimization. It is assumed that the reader is familiar with process dynamics, even though some simple models are developed II Preface and explained. The book uses a very practical approach to problems and gives many examples .If the user is disappointed because a thorough treatment of the underlying theory is missing, we would like to refer him or her to the many excellent books on process dynamics, control and optimisation. Many of these books miss, however, the practical solution and implementation of the solution in a simulation environment. Rather, many books dwell on theoretical considerations and...

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