Chemical Process Retrofitting and Revamping

Techniques and Applications

Gade Pandu Rangaiah

• Publisher: Wiley
• Year: 2016
• Print ISBN: 9781119016335
• eBook ISBN: 9781119016304
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Engineering General
• Index: Technology & Engineering

The proposed book will be divided into three parts. The chapters in Part I provide an overview of certain aspect of process retrofitting. The focus of Part II is on computational techniques for solving process retrofit problems. Finally, Part III addresses  retrofit applications from diverse process industries.

Some chapters in the book are contributed by practitioners whereas others are from academia. Hence, the book includes both new developments from research and also practical considerations. Many chapters include examples with realistic data. All these feature make the book useful to industrial engineers, researchers and students.

Part I

Overview

1
Introduction

G.P. Rangaiah

Department of Chemical & Biomolecular Engineering, National University of Singapore, Singapore

1.1 Chemical Process Plants

There are a wide range of chemical process industries such as agrochemicals, ceramics, cement, cosmetics, fragrances and flavors, food and drinks, glass, industrial gases, industrial/inorganic chemicals, leather, mineral processing, nuclear, oil and gas, paper and pulp, paints and pigments, petrochemicals, pharmaceuticals, polymers, rubber, soap and detergent, specialty chemicals, synthetic fibers, sugar, vegetable oils and water. Many of these involve continuous processes whereas some are batch processes. New process plants continue to be designed and built, relatively more in developing countries, to produce useful and valuable products required by the society. These are usually designed and their economic viability assessed assuming a plant life of 10 to 20 years. However, chemical plants, once built, continue to operate for very much longer than this assumed plant life.

Thus, chemical process plants in operation have been increasing steadily in the world. They were designed in the past few years or even decades, perhaps optimally for the economic, technological and societal conditions at that time. Obviously, technological knowledge has been advancing since the existing plants were designed. In addition, economic and societal conditions are dynamic and change over time for one reason or other. For example, energy prices and global warming concerns have increased substantially; new and better technologies (such as catalysts, process equipment and their internals), separation processes and intensified processes as well as simulation and optimization techniques are being continually developed and improved through research and industrial implementation.

Hence, it is imperative to review regularly the performance of the existing plants and assess the possibilities for their improvement. This can be for one or more of the following objectives (Grossmann et al., 1987; Rong et al., 2000).

• To reduce energy required and/or operating cost
• To improve conversion and/or selectivity of reactions
• To increase production/throughput of the process
• To use feed of different quality and/or alternative feed
• To meet new specifications of product(s)
• To produce new products
• To enhance the control of the process
• To improve the safety, reliability and flexibility of the process
• To reduce the adverse impact of the process on the environment.

The first and relatively simple step is to optimize and set the operating conditions such as temperature, pressure and flow rate in the existing process for the chosen objective (for example, energy required and operating cost). This is often referred to as operation optimization, and involves analysis of the process and use of optimization techniques. In operation optimization, there is no change in process configuration or equipment. It can be performed off-line or on-line because of frequent changes in the operating environment of the process (such as product requirements and prices). On-line optimization is also known as real time optimization. Process improvement by operation optimization is limited because of constraints imposed by current process configuration, equipment and/or technology employed. It is thus necessary to consider modifications in all these for improving the current process substantially.

1.2 Process Retrofitting and Revamping

Process retrofitting and revamping refers to making suitable changes and/or additions to existing process configuration and equipment. It may involve new technology such as membrane separation or reactive distillation to supplement or replace distillation. One example of equipment and configuration changes in a process is heat exchanger network retrofitting, which involves area additions in existing exchangers and/or installation of new exchangers for increased energy recovery and re-use. Obviously, process retrofitting and revamping should maximize the use of the existing equipment in the plant as much as possible.

Analysis, simulation and optimization techniques could be used to achieve the chosen objective of process retrofitting/revamping. However, process retrofitting/revamping is more than operation optimization because the former considers changes to the process configuration and equipment in addition to operating conditions. Hence, solving a process retrofitting/revamping problem and implementing the solution found ar...

Table of contents

• Cover
• Dedication
• Title Page
• Copyright
• List of Contributors
• Preface
• Part I: Overview
• Part II: Techniques for Retrofitting and Revamping
• Part III: Retrofitting and Revamping Applications
• Index
• EULA