Dewatering, Desalting, and Distillation in Petroleum Refining

271 Pages·2022·5.602 MB·English

by  James G. Speight

Dewatering, Desalting, and
Distillation in Petroleum
Refining
This book presents a detailed and practical description of various processes – dewatering, desalt-
ing, and distillation – that prepare refinery feedstocks for different conversion processes they will
go through. Relevant process data are provided, and process operations are fully described. This
accessible guide is written for managers, professionals, and technicians as well as graduate students
transitioning into the refining industry.
Key Features:
• Describes feedstock evaluation and the effects of elemental, chemical, and fractional
composition.
• Details the equipment and components and possible impacts due to composition.
• Explores the process options and parameters involved in dewatering, desalting, and
distillation.
• Considers next-generation processes and developments.
Petroleum Refining Technology Series
Series Editor:
James G. Speight
This series of books is designed to address the current processes used by the refining industry
and take the reader through various steps that are necessary for crude oil evaluation and refining.
Technological advancements and processing innovations are highlighted in each of the volumes.
Refinery Feedstocks
James G. Speight
Dewatering, Desalting, and Distillation in Petroleum Refining
James G. Speight
Dewatering, Desalting, and
Distillation in Petroleum
Refining
James G. Speight
Cover image: © Shutterstock
First edition published 2023
by CRC Press
6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742
and by CRC Press
4 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN
CRC Press is an imprint of Taylor & Francis Group, LLC
© 2023 James G. Speight
Reasonable efforts have been made to publish reliable data and information, but the author and publisher
cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and
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Library of Congress Cataloging‑in‑Publication Data
Names: Speight, James G., author.
Title: Dewatering, desalting, and distillation in petroleum refining / James G. Speight.
Description: First edition. | Boca Raton : CRC Press, 2022. | Series:
Dewatering, desalting, and distillation in petroleum refining |
Includes bibliographical references and index.
Identifiers: LCCN 2022028320 | Subjects: LCSH: Petroleum—Refining—Desalting. | Petroleum—Dewatering. |
Distillation, Fractional. Classification: LCC TP690.45 .S6283 2022 | DDC 622/.3382—dc23/eng/20220808
LC record available at https://lccn.loc.gov/2022028320
ISBN: 9781032027340 (hbk)
ISBN: 9781032027388 (pbk)
ISBN: 9781003184959 (ebk)
DOI: 10.1201/9781003184959
Typeset in Times
by codeMantra
Contents
Preface...............................................................................................................................................ix
Author ...............................................................................................................................................xi
Chapter 1 Refinery Operations .....................................................................................................1
1.1 Introduction .......................................................................................................1
1.2 Refinery Configuration ......................................................................................2
1.2.1 The Topping Refinery ...........................................................................4
1.2.2 The Hydroskimming Refinery .............................................................5
1.2.3 The Conversion Refinery ......................................................................5
1.3 Refinery Feedstocks ..........................................................................................6
1.3.1 Conventional Crude Oil........................................................................7
1.3.2 Foamy Oil .............................................................................................9
1.3.3 High-Acid Crude Oil ..........................................................................10
1.3.4 Opportunity Crude Oil .......................................................................11
1.3.5 Tight Oil .............................................................................................13
1.3.6 Heavy Crude Oil ................................................................................13
1.3.7 Extra Heavy Crude Oil .......................................................................15
1.3.8 Tar Sand Bitumen ...............................................................................16
1.3.9 Alternate Terminology .......................................................................18
1.4 Alternate Feedstocks .......................................................................................20
1.4.1 Coal Liquids .......................................................................................20
1.4.2 Shale Oil .............................................................................................21
1.4.3 Bio-oil .................................................................................................23
1.5 Feedstock Evaluation .......................................................................................27
1.5.1 Crude Oil Assay .................................................................................27
1.5.2 Elemental Composition ......................................................................28
1.5.3 Chemical Composition .......................................................................29
1.5.4 Fractional Composition Using Solvents .............................................32
1.5.4.1 Asphaltene Separation ........................................................32
1.5.4.2 Fractionation .......................................................................34
1.5.4.3 Adsorption Methods ...........................................................34
1.5.4.4 General Methods ................................................................34
1.5.4.5 USBM–API and SARA Methods .......................................35
1.5.4.6 ASTM Methods ..................................................................36
1.5.5 Fractionation by Distillation ...............................................................36
1.5.5.1 Gases and Naphtha .............................................................37
1.5.5.2 Middle Distillates ...............................................................37
1.5.5.3 Vacuum Residua .................................................................39
1.6 Potential for Corrosion and Fouling of Equipment .........................................40
References ..................................................................................................................42
Chapter 2 Dewatering and Desalting ..........................................................................................47
2.1 Introduction .....................................................................................................47
2.2 Dewatering ......................................................................................................51
2.2.1 Process Description ............................................................................53
v
vi Contents
2.2.2 Equipment ..........................................................................................54
2.3 Desalting ..........................................................................................................55
2.3.1 Process Description ............................................................................60
2.3.2 Equipment ..........................................................................................66
2.4 Process Options for Heavy Feedstocks ...........................................................70
2.5 Potential for Corrosion and Fouling of Equipment .........................................73
References ..................................................................................................................77
Chapter 3 Feedstock Blending ....................................................................................................79
3.1 Introduction .....................................................................................................79
3.2 Blending ...........................................................................................................80
3.2.1 Process Description ............................................................................81
3.2.2 Equipment ..........................................................................................83
3.3 Incompatibility and Instability of Blends ........................................................85
3.4 Factors Affecting Incompatibility of Blends ...................................................94
3.4.1 Acidity ................................................................................................95
3.4.2 Asphaltene Content ............................................................................96
3.4.3 Density/Specific Gravity ....................................................................97
3.4.4 Elemental Composition ......................................................................98
3.4.5 Metals Content ...................................................................................98
3.4.6 Pour Point ...........................................................................................99
3.4.7 Viscosity .............................................................................................99
3.4.8 Volatility .............................................................................................99
3.4.9 Water Content, Salt Content, and Bottom Sediment and Water ........99
3.5 D etermining Incompatibility of Blends ........................................................100
3.6 P otential for Corrosion and Fouling of Equipment .......................................105
References ................................................................................................................107
Chapter 4 Distillation ................................................................................................................111
4.1 I ntroduction ...................................................................................................111
4.2 F eedstock Evaluation .....................................................................................113
4.3 D istillation .....................................................................................................116
4.3.1 Distillation at Atmospheric Pressure................................................122
4.3.2 Distillation at Reduced Pressure ......................................................127
4.4 D istillation Towers.........................................................................................134
4.4.1 Tray Tower ........................................................................................136
4.4.2 Packed Tower ....................................................................................138
4.5 P rocess Options for Heavy Feedstocks .........................................................138
4.6 P otential for Corrosion and Fouling of Equipment .......................................140
4.7 T he Future .....................................................................................................148
References ................................................................................................................151
Chapter 5 Ancillary Distillation Processes ...............................................................................155
5.1 I ntroduction ...................................................................................................155
5.2 A ncillary Processes .......................................................................................159
5.2.1 Azeotropic Distillation .....................................................................160
5.2.2 Batch Distillation ..............................................................................163
5.2.3 Extractive Distillation ......................................................................164
Contents vii
5.2.4 Flash Vaporization ...........................................................................167
5.2.5 Pressure-Swing Distillation .............................................................168
5.2.6 Reactive Distillation .........................................................................169
5.2.7 Rerunning .........................................................................................170
5.2.8 Steam Distillation .............................................................................170
5.2.9 Stripping ...........................................................................................171
5.2.10 Stabilization and Light Ends Removal .............................................172
5.2.11 Superfractionation ............................................................................174
5.3 Potential for Corrosion and Fouling of Equipment .......................................175
References ................................................................................................................175
Chapter 6 Importance in the Refinery ......................................................................................177
6.1 Introduction ...................................................................................................177
6.2 Dewatering and Desalting .............................................................................178
6.3 Corrosion and Fouling ...................................................................................182
6.3.1 Corrosion ..........................................................................................183
6.3.2 Fouling .............................................................................................189
6.4 Types of Corrosion and Fouling ....................................................................193
6.4.1 Acidic Corrosion ..............................................................................194
6.4.2 Carbon Dioxide Corrosion ...............................................................197
6.4.3 Carburization ....................................................................................197
6.4.4 Cooling Water Corrosion .................................................................198
6.4.5 Crude Oil Quality .............................................................................198
6.4.6 Temperature-Dependent Corrosion ..................................................199
6.4.6.1 Low-Temperature Corrosion .............................................199
6.4.6.2 High-Temperature Corrosion ............................................199
6.4.7 Sulfidic Corrosion ............................................................................200
6.5 Corrosion and Fouling Management .............................................................201
References ................................................................................................................204
Glossary ........................................................................................................................................209
Index ..............................................................................................................................................257

Preface
As the second book of the refinery series, this book presents a description of various dewatering,
desalting, and distillation processes that prepare the refinery feedstocks for various conversion pro-
cesses that lead to the production of specification grade products.
Crude oil introduced to a refinery for any form of processing contains many undesirable impuri-
ties, such as sand, inorganic salts, drilling mud, polymer, and corrosion byproduct. The purpose of
crude oil dewatering and desalting is to remove these undesirable impurities, especially salts and
water, from the crude oil prior to distillation. During this processing, steps are necessary to remove
the oleophobic impurities and typically they occur in two ways which are (1) field separation and
(2) dewatering and desalting. Field separation after the crude oil is produced from the reservoir is
the first step in which gases are removed and the water and dirt that accompany crude oil coming
from the ground and are located in the field near the site of the wells.
The first processes (desalting and dewatering) are focused on the cleanup of the feedstock,
particularly the removal of the troublesome brine constituents. This is followed by distillation to
remove the volatile constituents with the concurrent production of a residuum that can be used as a
cracking (coking) feedstock or as a precursor to asphalt. Other methods of feedstock treatment that
involve the concept of volatility are also included here even though some of the methods (such as
stripping and rerunning) might also be used for product purification. However, the distillation step
has recently been recognized as a viable step that produces additional valuable high-boiling frac-
tions for the bitumen.
The book is designed to address the processes involved in the cleanup (dewatering and desalting)
of crude oil and various aspects of distillation leading to the production of bulk products that are
sent for further refining to produce saleable products.
Chapter 1 presents an overview of various types of feedstocks that are currently accepted and
used by refineries and emphasizes on the dewatering, desalting, and distillation processes within a
refinery. This chapter also presents description of the nature of the dewatering, desalting, and dis-
tillation processes, and the behavior of these feedstocks in dewatering and desalting operations in
these processes needs to be better understood.
Chapter 2 presents the process options that can be used for the dewatering and desalting pro-
cesses that prepare the feedstock for introduction to the distillation section of the refinery and then
to a variety of conversion processes which are often, incorrectly, referred to as refining proper.
This chapter also includes process options for heavy feedstocks and the potential for corrosion and
fouling of refinery equipment if the dewatering–desalting processes are not performed with the
maximum efficiency.
Chapter 3 introduces the concept of incompatibility (and instability) of feedstocks in the refin-
ery and how this event might be affected by dewatering-desalting and distillation processes. In
addition, some of the more prominent methods are used for determining the potential for incom-
patibility and instability of crude oil feedstocks and crude oil products. The choice of the method
is subject to the composition and properties of the feedstock and the process parameters as well
as desired product.
Chapter 4 presents a description of the distillation processes that are applied to a feedstock in a
refinery which remove the volatile constituents with the concurrent production of a residuum that
can be used as a cracking (coking) feedstock or as a precursor to asphalt. Current methods of bitu-
men processing involve direct use of the bitumen as feedstock for delayed or fluid coking.
Chapter 5 deals with the ancillary distillation processes. Because of the presence of the lower
boiling and higher boiling constituents within each side-stream distillation fraction, there is a need
to reprocess the side-stream fractions using any one (or more of a variety of processes to ensure that
the requirements of the distillation fractions are met.
ix