the chemistry and technology of petroleum,3rd edition

The uses of petroleum as a source of raw material in manufacturing are central to the functioning of modern industry.Petroleum refining is now in a significant transition period as the i

Speight, J G.

The chemistry and technology of petroleum / James G Speight.—3rd ed.,

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3 The Chemistry and Technology of Petroleum, James G Speight

4 The Desulfurization of Heavy Oils and Residua, James G Speight

5 Catalysis of Organic Reactions, edited by William R Moser

6 Acetylene-Based Chemicals from Coal and Other Natural Resources, Robert J.

Tedeschi

7 Chemically Resistant Masonry, Walter Lee Sheppard, Jr.

8 Compressors and Expanders: Selection and Application for the Process Industry,

Heinz P Bloch, Joseph A Cameron, Frank M Danowski, Jr., Ralph James, Jr.,Judson S Swearingen, and Marilyn E Weightman

9 Metering Pumps: Selection and Application, James P Poynton

10 Hydrocarbons from Methanol, Clarence D Chang

11 Form Flotation: Theory and Applications, Ann N Clarke and David J Wilson

12 The Chemistry and Technology of Coal, James G Speight

13 Pneumatic and Hydraulic Conveying of Solids, O A Williams

14 Catalyst Manufacture: Laboratory and Commercial Preparations, Alvin B Stiles

15 Characterization of Heterogeneous Catalysts, edited by Francis Delannay

16 BASIC Programs for Chemical Engineering Design, James H Weber

17 Catalyst Poisoning, L Louis Hegedus and Robert W McCabe

18 Catalysis of Organic Reactions, edited by John R Kosak

19 Adsorption Technology: A Step-by-Step Approach to Process Evaluation and

Application, edited by Frank L Slejko

20 Deactivation and Poisoning of Catalysts, edited by Jacques Oudar and Henry

Wise

21 Catalysis and Surface Science: Developments in Chemicals from Methanol,

Hydrotreating of Hydrocarbons, Catalyst Preparation, Monomers and Polymers, Photocatalysis and Photovoltaics, edited by Heinz Heinemann and Gabor A.

Somorjai

22 Catalysis of Organic Reactions, edited by Robert L Augustine

23 Modern Control Techniques for the Processing Industries, T H Tsai, J W Lane,

and C S Lin

24 Temperature-Programmed Reduction for Solid Materials Characterization, Alan

Jones and Brian McNichol

25 Catalytic Cracking: Catalysts, Chemistry, and Kinetics, Bohdan W Wojciechowski

and Avelino Corma

26 Chemical Reaction and Reactor Engineering, edited by J J Carberry and A.

Varma

and Clyde Orr

28 Corrosion Mechanisms, edited by Florian Mansfeld

29 Catalysis and Surface Properties of Liquid Metals and Alloys, Yoshisada Ogino

30 Catalyst Deactivation, edited by Eugene E Petersen and Alexis T Bell

31 Hydrogen Effects in Catalysis: Fundamentals and Practical Applications, edited by

Zoltán Paál and P G Menon

32 Flow Management for Engineers and Scientists, Nicholas P Cheremisinoff and

Paul N Cheremisinoff

33 Catalysis of Organic Reactions, edited by Paul N Rylander, Harold Greenfield,

and Robert L Augustine

34 Powder and Bulk Solids Handling Processes: Instrumentation and Control, Koichi

Iinoya, Hiroaki Masuda, and Kinnosuke Watanabe

35 Reverse Osmosis Technology: Applications for High-Purity-Water Production, edited

by Bipin S Parekh

36 Shape Selective Catalysis in Industrial Applications, N Y Chen, William E.

Garwood, and Frank G Dwyer

37 Alpha Olefins Applications Handbook, edited by George R Lappin and Joseph L.

Sauer

38 Process Modeling and Control in Chemical Industries, edited by Kaddour Najim

39 Clathrate Hydrates of Natural Gases, E Dendy Sloan, Jr.

40 Catalysis of Organic Reactions, edited by Dale W Blackburn

41 Fuel Science and Technology Handbook, edited by James G Speight

42 Octane-Enhancing Zeolitic FCC Catalysts, Julius Scherzer

43 Oxygen in Catalysis, Adam Bielanski and Jerzy Haber

44 The Chemistry and Technology of Petroleum: Second Edition, Revised and

Expanded, James G Speight

45 Industrial Drying Equipment: Selection and Application, C M van't Land

46 Novel Production Methods for Ethylene, Light Hydrocarbons, and Aromatics,

edited by Lyle F Albright, Billy L Crynes, and Siegfried Nowak

47 Catalysis of Organic Reactions, edited by William E Pascoe

48 Synthetic Lubricants and High-Performance Functional Fluids, edited by Ronald L.

Shubkin

49 Acetic Acid and Its Derivatives, edited by Victor H Agreda and Joseph R Zoeller

50 Properties and Applications of Perovskite-Type Oxides, edited by L G Tejuca

53 Catalysis of Organic Reactions, edited by John R Kosak and Thomas A Johnson

54 Composition and Analysis of Heavy Petroleum Fractions, Klaus H Altgelt and

Mieczyslaw M Boduszynski

55 NMR Techniques in Catalysis, edited by Alexis T Bell and Alexander Pines

56 Upgrading Petroleum Residues and Heavy Oils, Murray R Gray

57 Methanol Production and Use, edited by Wu-Hsun Cheng and Harold H Kung

58 Catalytic Hydroprocessing of Petroleum and Distillates, edited by Michael C.

Oballah and Stuart S Shih

59 The Chemistry and Technology of Coal: Second Edition, Revised and Expanded,

James G Speight

60 Lubricant Base Oil and Wax Processing, Avilino Sequeira, Jr.

61 Catalytic Naphtha Reforming: Science and Technology, edited by George J.

Antos, Abdullah M Aitani, and JoséM Parera

62 Catalysis of Organic Reactions, edited by Mike G Scaros and Michael L Prunier

63 Catalyst Manufacture, Alvin B Stiles and Theodore A Koch

64 Handbook of Grignard Reagents, edited by Gary S Silverman and Philip E Rakita

65 Shape Selective Catalysis in Industrial Applications: Second Edition, Revised and

Expanded, N Y Chen, William E Garwood, and Francis G Dwyer

66 Hydrocracking Science and Technology, Julius Scherzer and A J Gruia

67 Hydrotreating Technology for Pollution Control: Catalysts, Catalysis, and

Processes, edited by Mario L Occelli and Russell Chianelli

68 Catalysis of Organic Reactions, edited by Russell E Malz, Jr.

69 Synthesis of Porous Materials: Zeolites, Clays, and Nanostructures, edited by

Mario L Occelli and Henri Kessler

70 Methane and Its Derivatives, Sunggyu Lee

71 Structured Catalysts and Reactors, edited by Andrzej Cybulski and Jacob A.

Moulijn

72 Industrial Gases in Petrochemical Processing, Harold Gunardson

73 Clathrate Hydrates of Natural Gases: Second Edition, Revised and Expanded, E.

Dendy Sloan, Jr

74 Fluid Cracking Catalysts, edited by Mario L Occelli and Paul O’Connor

75 Catalysis of Organic Reactions, edited by Frank E Herkes

76 The Chemistry and Technology of Petroleum: Third Edition, Revised and

Ex-panded, James G Speight

77 Synthetic Lubricants and High-Performance Functional Fluids: Second Edition,

Revised and Expanded, Leslie R Rudnick and Ronald L Shubkin

78 The Desulfurization of Heavy Oils and Residua, Second Edition, Revised and

Expanded, James G Speight

79 Reaction Kinetics and Reactor Design: Second Edition, Revised and Expanded,

82 Catalysis of Organic Reactions, edited by Michael E Ford

83 The Chemical Process Industries Infrastructure: Function and Economics,

James R Couper, O Thomas Beasley, and W Roy Penney

84 Transport Phenomena Fundamentals, Joel L Plawsky

85 Petroleum Refining Processes, James G Speight and BakiÖzüm

86 Health, Safety, and Accident Management in the Chemical Process Industries,

Ann Marie Flynn and Louis Theodore

87 Plantwide Dynamic Simulators in Chemical Processing and Control, William L.

Luyben

88 Chemicial Reactor Design, Peter Harriott

89 Catalysis of Organic Reactions, edited by Dennis Morrell

90 Lubricant Additives: Chemistry and Applications, edited by Leslie R Rudnick

91 Handbook of Fluidization and Fluid-Particle Systems, edited by Wen-Ching

Yang

92 Conservation Equations and Modeling of Chemical and Biochemical Processes,

Said S E H Elnashaie and Parag Garhyan

93 Batch Fermentation: Modeling, Monitoring, and Control, Ali Cinar, Satish J.Parulekar, CenkÜndey, and Gülnur Birol

94 Industrial Solvents Handbook, Second Edition, Nicholas P Cheremisinoff

Chemical Process Engineering: Design and Economics, Harry Silla

Process Engineering Economics, James R Couper

Petroleum and Gas Field Processing, H K Abdel-Aal, Mohamed Aggour, and

Preface to the Third Edition

Since the publication of the second edition, the refining industry has continued to evolve andthere is an increasing need to develop options to upgrade the abundant supply of known heavyoil reserves into more value-added products In addition, there has been an increased emphasis

on the need to understand the structure of petroleum and how this structure affects conversionprocesses and the nature of the products Indeed, the incompatibility of different feedstocks andtheir respective products has also received considerable attention This book follows that evolu-tion with the inclusion of chapters on the structure of petroleum and the development of newtechnologies for refining the heavier feedstocks

The success of the first and second editions of this text has been the primary factor in thedecision to publish a third edition Petroleum is perhaps the most important substance consumed

in modern society It provides not only raw materials for the ubiquitous plastics and other ucts, but also fuel for energy, industry, heating, and transportation From a chemical standpointpetroleum is an extremely complex mixture of hydrocarbon compounds, usually with minoramounts of nitrogen-, oxygen-, and sulfur-containing compounds as well as trace amounts ofmetal-containing compounds

prod-Petroleum remains the main source of liquid fuels The fuels that are derived from leum supply more than half of the world’s total supply of energy Gasoline, kerosene, and dieseloil provide fuel for automobiles, tractors, trucks, aircraft, and ships Fuel oil and natural gasare used to heat homes and commercial buildings, as well as to generate electricity Petroleumproducts are the basic materials used for the manufacture of synthetic fibers for clothing and

petro-in plastics, papetro-ints, fertilizers, petro-insecticides, soaps, and synthetic rubber The uses of petroleum

as a source of raw material in manufacturing are central to the functioning of modern industry.Petroleum refining is now in a significant transition period as the industry moves into the21st century and the demand for petroleum products has shown a sharp growth in recent years.The demand for light fuel oils for transport purposes is forecast to show steady growth in thefuture, surely contributing to petroleum product demand patterns toward lighter oils The sim-plest means to cover the demand growth in light-oil products is to increase the imports of lightcrude oils and light petroleum products, but these steps may be limited in the future

Ultimately the essential step required of refineries is to upgrade heavy feedstocks, larly residua In fact, the increased supply of heavy crude oils is a matter of serious concern

particu-iii

for the petroleum industry In order to satisfy the changing pattern of product demand, significantinvestments in refining conversion processes will be necessary to profitably utilize these heavycrude oils The most efficient and economical solution to this problem will depend to a largeextent on individual country and company situations However, the most promising technologieswill likely involve the conversion of vacuum bottom residual oils, asphalt from deasphaltingprocesses, and super-heavy crude oils into useful light and middle distillate products.

The more efficient use of petroleum is of paramount importance Petroleum technology,

in one form or another, is with us until suitable alternative forms of energy are readily available.Therefore, a thorough understanding of the benefits and limitations of petroleum recovery andprocessing is necessary and is introduced within the pages of this book

Finally, I am indebted to my colleagues in many different countries who have continued

to engage me in lively discussions and who have offered many thought-provoking comments.Thanks are also owed to those who have made constructive comments on the first edition, whichwere of great assistance in the writing of the second edition and have been helpful in formulatingthe contents and expanded sections of this third edition For such discussions and commentary,

I continue to be grateful

James G Speight

Preface to the Second Edition

The success of the first edition of this text has been the primary factor in the decision to publish

a second edition This second edition has been greatly expanded and rewritten to be more inkeeping with the technological aspects of the petroleum industry For example, the originalsection on petroleum recovery has been expanded to such an extent that it is now worthy of aseparate chapter The origin of petroleum has been the subject of much discussion of late; accord-ingly, this section has also been expanded to such an extent that it was thought necessary toinclude a chapter on kerogen There are also expanded updates on the nature of the asphalticconstituents of petroleum and how such constituents might be related to kerogen

Since the first edition, there have been many changes in the refining industry The overallcharacter of the feedstocks entering refineries has changed to such an extent that the differencecan be measured by a decrease of several points on the API gravity scale Hence, in this edition,frequent reference is made to refining of the heavier feedstocks, such as the heavy oils andbitumens There is also a more detailed section on the nature of the porphyrinic constituents ofpetroleum as well as a section on how these particular constituents behave during refinery opera-tions There are also additions to the original chapter on refining chemistry so that the readercan obtain a better understanding of the chemistry involved in the processing of the heavierfeedstocks In addition, environmental issues have become of such importance that a vastlyexpanded section on the cleanup of refinery gases and of natural gas (as it occurs with petroleum)

is now also a separate chapter Finally, there are also further updates on the nature of petroleumproducts as well as petrochemicals

In addition, this edition has references cited throughout the text, in contrast to the firstedition, which contained general references provided in the form of bibliographies at the end

of each chapter The decision to cite the references in the text will guide the reader to the originalarticle for more detail I would also like to mention that there are many thousands of referencescontained in my personal files No attempt has been made to include all these references I haveincluded those references that might give the reader the most information

There are many people who should be thanked for their assistance in the preparation ofthis text My sincere appreciation is expressed to Professors Gordon Harris and Jack Evers,Department of Petroleum Engineering, University of Wyoming, for the loan of the drill bits(Figure 5, Chapter 5)

v

The following oil companies, which contributed photographs of refinery operations, arealso gratefully acknowledged: Phillips Petroleum Company (Figure 11, Chapter 5), SinclairRefinery (Figure 12, Chapter 13; and Figure 12, Chapter 15), Shell Oil Company (Figure 13,Chapter 13; and Figure 11, Chapter 15), Sun Oil Company (Figure 14, Chapter 13; and Figure

1, Chapter 19), and Chevron Oil Company (Figure 18, Chapter 16; and Figure 5, Chapter 19).Finally, the author is indebted to his colleagues in many different countries who haveengaged him in lively discussions and have been responsible for many thought-provoking com-ments Thanks are also owed to those colleagues who have made constructive comments on thefirst edition, which have been of great assistance in the writing of the second edition Such isthe nature of scientists, and I am grateful

James G Speight

Preface to the First Edition

For many years petroleum has been regarded as the cheapest source of liquid fuels by manycountries, especially the United States and Canada However, with recent ‘‘energy crises’’ andconcern over future supplies of gaseous and liquid fuels in many parts of the world, particularlywestern Europe and North America, we have seen a gradual acceptance by the petroleum indus-try and the general public of the inevitability that petroleum and natural gas will, at some timewithin the foreseeable future, be in very short supply

As a result, petroleum technology is being expanded to such an extent that wells thatwere previously regarded as nonproductive because of their inability to produce oil withoutconsiderable external stimulation are now being reexamined with the object of, literally, recov-ering every last possible ‘‘drop’’ of petroleum

Serious attempts are also underway to produce liquid fuels from unconventional sources,such as coal, oil shale, and oil sands (also variously referred to as tar sands or bituminous sands).Oil sands, in fact, have already been developed to such an extent that commercial production

of a synthetic crude oil from the oils sands located in northeastern Alberta (Canada) has beenunderway for some ten years, with a second plant on-stream since 1978 and serious negotiationsunderway for other oil sands plants

This expansion of liquid fuels technology has resulted in a vacuum in the labor outputinsofar as the universities have been unable to produce sufficient people with any form of training

in petroleum technology and petroleum chemistry However, it now appears that various sities, which have initiated research into the various aspects of petroleum science, are nowconsidering some form of formal training in this area

univer-Thus it happened that during the winter of 1976–1977 the author organized a courseentitled ‘‘An Introduction to the Chemistry of Petroleum’’ through the Faculty of Extension atthe University of Alberta In the early stages of preparation, it became apparent that, althoughseveral older books were available, there was no individual book that could serve as a teachingtext for teachers and engineers as well as chemists Therefore, this book is the outcome of thecopious notes collected as a result of that course The text introduces the reader to the science

of petroleum, beginning with its formation in the ground, and eventually leads to analyses ofthe production of a wide variety of petrochemical intermediates as well as the more conventionalfuel products This book has also been written for those people already engaged in the petroleum

vii

industry (engineers and chemists) who wish to gain a general overview of the science of leum.

petro-Although any text on petroleum must of necessity include some chemistry, attempts havebeen made, for the benefit of those readers without any formal college training in chemistry,

to keep the chemical sections as simple as possible In fact, there are, within the text, severalpages of explanatory elementary organic chemistry for the benefit of such people

At a time when the anglicized nations of the world are undergoing a transferral to themetric system of measurement, there are still those disciplines that are based upon such scales

as the Fahrenheit temperature scale as well as the foot measure instead of the meter Accordingly,the text contains both the metric and nonmetric measures, but it should be noted that exactconversion is not often feasible, and thus conversion data are often taken to the nearest wholenumber Indeed, conversions involving the two temperature scales—Fahrenheit and Celsius—are, at the high temperatures quoted in the text, often ‘‘rounded off ’’ to the nearest 5°, especially

when serious error would not arise from such a conversion

For the sake of simplicity, illustrations contained in the text, especially in the chapterrelating to petroleum refining, are line drawings, and no attempt has been made to draw to scalethe various reactors, distillation towers, or other equipment

The majority of the work on this text was carried out while the author was a staff member

of the Alberta Research Council Thus, the author wishes to acknowledge the assistance given

by the many members of the Alberta Research Council The author is particularly indebted tohis colleagues Mr J F Fryer and Dr S E Moschopedis for their comments on the manuscript,

as well as to Mrs P Williams, Mrs M A Harris, and Mrs H Radvanyi for typing the script

manu-James G Speight

Preface to the Third Edition iii

Preface to the Second Edition v

Preface to the First Edition vii

Part I History, Occurrence, and Recovery

1 History and Terminology 1

2 Molecular Species in Petroleum 469

3 The Structure of Petroleum 475

4 The Stability/Instability of the Crude Oil System 483

2 Instability and Incompatibility 822

3 Factors Influencing Instability and Incompatibility 823

4 Methods for Determining Instability and Incompatibility 828

5 Instability and Incompatibility in Petroleum Products 831

References 832

23 Petrochemicals 835

1 Introduction 835

2 Chemicals from Paraffins 840

3 Chemicals from Olefins 843

4 Chemicals from Aromatics 847

5 Chemicals from Natural Gas 848

6 Inorganic Petrochemicals 850

7 Synthesis Gas 851

References 853

Part IV Environmental Issues

24 Environmental Aspects of Refining 854

1 Introduction 854

2 Definitions 857

3 Environmental Regulations 859

industry, heating, and transportation The word petroleum, derived from the Latin petra and

oleum, means literally rock oil and refers to hydrocarbons that occur widely in the sedimentary

rocks in the form of gases, liquids, semisolids, or solids

From a chemical standpoint petroleum is an extremely complex mixture of hydrocarboncompounds, usually with minor amounts of nitrogen-, oxygen-, and sulfur-containing com-pounds as well as trace amounts of metal-containing compounds (Chapter 6)

The fuels that are derived from petroleum supply more than half of the world’s totalsupply of energy Gasoline, kerosene, and diesel oil provide fuel for automobiles, tractors, trucks,aircraft, and ships Fuel oil and natural gas are used to heat homes and commercial buildings,

as well as to generate electricity Petroleum products are the basic materials used for the facture of synthetic fibers for clothing and in plastics, paints, fertilizers, insecticides, soaps, andsynthetic rubber The uses of petroleum as a source of raw material in manufacturing are central

manu-to the functioning of modern industry

Petroleum is a carbon-based resource Therefore, the geochemical carbon cycle is also ofinterest to fossil fuel usage in terms of petroleum formation, use, and the buildup of atmosphericcarbon dioxide (Chapter 24) Thus, the more efficient use of petroleum is of paramount impor-tance Petroleum technology, in one form or another, is with us until suitable alternative forms

of energy are readily available (Boyle, 1996; Ramage, 1997) Therefore, a thorough ing of the benefits and limitations of petroleum recovery and processing is necessary and, hope-fully, can be introduced within the pages of this book

understand-The history of any subject is the means by which the subject is studied in the hopes that

much can be learned from the events of the past In the current context, the occurrence and use

of petroleum, petroleum derivatives (naphtha), heavy oil, and bitumen is not new The use ofpetroleum and its derivatives was practiced in pre-Christian times and is known largely throughhistorical use in many of the older civilizations (Henry, 1873; Abraham, 1945; Forbes, 1958a,b;James and Thorpe, 1994) Thus, the use of petroleum and the development of related technology

1

is not such a modern subject as we are inclined to believe However, the petroleum industry isessentially a twentieth-century industry but to understand the evolution of the industry, it isessential to have a brief understanding of the first uses of petroleum.

Although it is possible to differentiate between the words bitumen and asphalt in modern

use, the occurrence of these words in older texts offers no such possibility It is significant thatthe early use of bitumen was in the nature of a cement for securing or joining together variousobjects, and thus it seems likely that the name itself was expressive of this application

The word asphalt is claimed to be derived from the Accadian term asphaltu or sphallo, meaning to split It was later adopted by the Homeric Greeks in the form of the adjective

α
σφαλη
ς, ⑀ς, signifying firm, stable, secure, and the corresponding verb α
σφαλι´ζω, ι´σω,

meaning to make firm or stable, to secure It is a significant fact that the first use of asphalt by

the ancients was in the nature of a cement for securing or joining together various objects, such

as the bricks used for building and it thus seems likely that the name itself was expressive of

this application From the Greek, the word passed into late Latin (asphaltum, aspaltum), and thence into French (asphalte) and English (aspaltoun).

The origin of the word bitumen is more difficult to trace and subject to considerable

speculation The word was proposed to have originated in the Sanskrit, where we find the words

jatu, meaning pitch, and jatukrit, meaning pitch creating From the Sanskrit, the word jatu was

incorporated into the Latin language as gwitu and is reputed to have eventually become gwitumen (pertaining to pitch) Another word, pixtumen (exuding or bubbling pitch) is also reputed to

have been in the Latin language, although the construction of this Latin word from which the

word bitumen was reputedly derived, is certainly suspect There is the suggestion that subsequent

derivation of the word led to a shortened version (which eventually became the modern version)

bituˆmen thence passing via French into English From the same root is derived the Anglo Saxon

word cwidu (mastic, adhesive), the German work kitt (cement or mastic) and the equivalent word kvada which is found in the old Norse language as being descriptive of the material used

to waterproof the long ships and other sea-going vessels It is just as (perhaps even more than) likely that the word is derived from the Celtic bethe or beithe or bedw which was the birch tree that was used as a source of resin (tar) The word appears in Middle English as bithumen In

summary, a variety of terms exist in ancient language from which, from their described use intexts, they can be proposed as having the meaning bitumen or asphalt (Table 1-1) (Abraham,1945)

Using these ancient words as a guide, it is possible to trace the use of petroleum and itsderivatives as described in ancient texts And, preparing derivatives of petroleum was well within

the area of expertise of the early scientists (perhaps refiners would be a better term) since

al-chemy (early chemistry) was known to consist of four sub-routines: dissolving, melting, ing, and distilling (Cobb and Goldwhite, 1995).

combin-Early references to petroleum and its derivatives occur in the Bible, although by the timethe various books of the Bible were written, the use of petroleum and bitumen was established.Nevertheless, these writings do offer documented examples of the use of petroleum and relatedmaterials

The caulking of a vessel with pitch is noted (Genesis 6 : 14):

Make thee an ark of gopher wood; rooms shalt thou make in the ark, and shalt pitch it within and without with pitch.

and the occurrence of slime (bitumen) pits in the Valley of Siddim (Genesis, 14 : 10), a valley

at the southern end of the Dead Sea, is reported There is also reference to the use of tar as amortar when the Tower of Babel was under construction (Genesis 11 : 3):

And they said one to another, Go to, let us make brick, and burn them throughly And they had brick for stone, and slime had they for mortar.

History and Terminology 3

Table 1-1 Linguistic Origins of Words Related to the Various Aspects of

Petroleum Technology

bitumenesir-lah hard/glossy asphaltesir-harsag rock asphaltesir-e´-a mastic asphaltesir-ud-du-a pitch

pitchs´ila¯-jatu rock asphaltas´maja¯tam-jatu rock asphaltAssyrian/Accadian idd¯, ittuˆ, it-tuˆ-u bitumen

kopher or kofer pitch

zift or zipht bitumen or pitch

humar (houmar) rock asphaltgasat (qasat) rock asphaltghir or gir asphalt mastickir or kafr asphalt mastic or pitch

pissasphaltos rock asphaltpittasphaltos rock asphaltpittolium rock asphaltpissa or pitta pitchampelitis mineral wax and asphaltites

bitumen liquidum soft asphalt

In the Septuagint, or Greek version of the Bible, this word is translated as asphaltos, and in the Vulgate or Latin version, as bitumen In the Bishop’s Bible of 1568 and in subsequent translations into English, the word is given as slime In the Douay translation of 1600, it is

bitume, while in Luther’s German version, it appears as thon, the German word for clay.

Another example of the use of pitch (and slime) is given in the story of Moses (Exodus

2 : 3):

And when she could not longer hide him, she took for him an ark of bulrushes, and daubed

it with slime and with pitch, and put the child therein; and she laid it in the flags by the river’s brink.

Perhaps the slime was a lower melting bitumen whereas the pitch was a higher melting material; the one (slime) acting as a flux for the other ( pitch) The lack of precise use of the words for

bitumen and asphalt as well as for tar and pitch even now makes it unlikely that the true nature

of the biblical tar, pitch, and slime will ever be known, but one can imagine their nature! In fact, even modern Latin dictionaries give the word bitumen as the Latin word for asphalt!

It is most probable that, in both these cases, the pitch and the slime were obtained from the

seepage of oil to the surface, which was a fairly common occurrence in the area And during biblicaltimes, bitumen was exported from Canaan to various parts of the countries that surround the Mediter-ranean (Armstrong, 1997) Hence the use of such material in Egypt to caulk Moses’ vessel

In terms of liquid products, there is an interesting reference (Deuteronomy, 32 : 13) to

bringing oil out of flinty rock The exact nature of the oil is not described nor is the nature of the rock The use of oil for lamps is also referenced (Matthew, 23 : 3) but whether is was mineral

oil (a petroleum derivative such as naphtha) or whether is was vegetable oil is not known.Excavations conducted at Mohenjo-Daro, Harappa, and Nal in the Indus Valley indicatedthat an advanced form of civilization existed there An asphalt mastic composed of a mixture

of asphalt, clay, gypsum, and organic matter was found between two brick walls in a layer about

25 mm thick, probably a waterproofing material Also unearthed was a bathing pool that tained a layer of mastic on the outside of its walls and beneath its floor

con-In the Bronze Age, dwellings were constructed on piles in lakes close to the shore tobetter protect the inhabitants from the ravages of wild animals and attacks from marauders.Excavations have shown that the wooden piles were preserved from decay by coating withasphalt, and posts preserved in this manner have been found in Switzerland There are alsoreferences to deposits of bitumen at Hit (the ancient town of Tuttul in Mesopotamia) and thebitumen from these deposits was transported to Babylon for use in construction (Herodotus,

The Histories, Book I) There is also reference (Herodotus, The Histories, Book IV) to a

Cartha-ginian story in which birds’ feathers smeared with pitch are used to recover gold dust from the

waters of a lake

One of the earliest recorded uses of asphalt was by the pre-Babylonian inhabitants of theEuphrates Valley in southeastern Mesopotamia, present-day Iraq, formerly called Sumer andAkkad and, later, Babylonia In this region there are various asphalt deposits, and uses of thematerial have become evident For example, King Sargon as an infant was reputed to have beenplaced by his mother in a reed basket coated with asphalt and set adrift on the waters of theEuphrates River during one of its frequent overflows On the other hand, the bust of Manishtusu,King of Kish, an early Sumerian ruler (about 2270 BC), was found in the course of excavations

at Susa in Persia, and the eyes, composed of white limestone, are held in their sockets with theaid of bitumen Fragments of a ring composed of asphalt have been unearthed above the floodlayer of the Euphrates at the site of the prehistoric city of Ur in southern Babylonia, ascribed

to the Sumerians of about 3500 BC

An ornament excavated from the grave of a Sumerian king at Ur consists of a statue of

a ram with the head and legs carved out of wood over which gold foil was cemented by means

of asphalt The back and flanks of the ram are coated with asphalt in which hair was embedded.Another art of decoration consisted in beating thin strips of gold or copper, which were thenfastened to a core of asphalt mastic An alternative method was to fill a cast metal object with

a core of asphalt mastic, and such specimens have been unearthed at Lagash and Nineveh.Excavations at Tell-Asmar, 50 miles northeast of Baghdad, revealed the use of asphalt by theSumerians for building purposes

Mortar composed of asphalt has also been found in excavations at Ur, Uruk, and Lagash,and excavations at Khafaje have uncovered floors composed of a layer of asphalt that has beenidentified as asphalt, mineral filler (loam, limestone, and marl), and vegetable fibers (straw).Excavations at the city of Kish (Persia) in the palace of King Ur-Nina showed that the founda-tions consist of bricks cemented together with an asphalt mortar Similarly, in the ancient city

of Nippur (about 60 miles south of Baghdad), excavations show Sumerian structures composed

History and Terminology 5

of natural stones joined together with asphalt mortar Excavation has uncovered an ancientSumerian temple in which the floors are composed of burnt bricks embedded in an asphaltmastic that still shows impressions of reeds with which it must originally have been mixed.The Epic of of Gilgamesh (written before 2500 BC) and transcribd on to clay tabletsduring the time of Assurbanipal, king of Assyria (668–626 BC), make reference to the use ofasphalt for building purposes In the eleventh tablet, Ut-Napishtim relates the well-known story

of the Babylonian flood, stating that he smeared

the inside of a boat with six sar of kupru and the outside with three sar

There are indications from these texts that asphalt mastic was sold by volume (by the gur) On the other hand, bitumen was sold by weight (by the mina or shekel ).

Use of asphalt by the Babylonians (1500 to 538 BC) is also documented The Babylonianswere well versed in the art of building, and each monarch commemorated his reign and perpetu-ated his name by the construction of a building or other monuments For example, the use ofbitumen mastic in cities such as Babylon, Nineveh, Calah, and Ur has been observed (Speight,1978) and the bitumen lines are still evident

Bitumen was used as mortar from very early times, and sand, gravel, or clay was employed

in preparing these mastics Asphalt-coated tree trunks were often used to reinforce wall cornersand joints, for instance in the temple tower of Ninmach in Babylon In vaults or arches, a mastic-loam composite was used as mortar for the bricks, and the keystone was usually dipped inasphalt before being set in place The use of bituminous mortar was said to have been introduced

in the city of Babylon by King Khammurabi, but the use of bituminous mortar was abandonedtoward the end of Nebuchadnezzar’s reign in favor of lime mortar to which varying amounts

of asphalt were added The Assyrians recommended the use of asphalt for medicinal purposes,

as well as for building purposes, and perhaps there is some merit in the fact that the Assyrianmoral code recommended that asphalt, in the molten state, be poured onto the heads of delin-quents Pliny, the Roman author, also notes that bitumen could be used to stop bleeding, healwounds, drive away snakes, treat cataracts as well as a wide variety of other diseases, andstraighten out eyelashes which inconvenience the eyes One can appreciate the use of bitumen

to stop bleeding but its use to cure other ailments is questionable and one has to consider whatother agents were being used concurrently with bitumen

The Egyptians were the first to adopt the practice of embalming their dead rulers andwrapping the bodies in cloth

Before 1000 BC, asphalt was rarely used in mummification, except to coat the cloth pings and thereby protect the body from the elements After the viscera had been removed, thecavities were filled with a mixture of resins and spices, the corpse immersed in a bath of potash

wrap-or soda, dried, and finally wrapped From 500 to about 40 BC, asphalt was generally used both

to fill the corpse cavities, as well as to coat the cloth wrappings The word muˆmuˆia first made

its appearance in Arabian and Byzantine literature about 1000 AD, signifying bitumen.

In Persian, the term bitumen is believed to have acquired the meaning equivalent to

paraf-fin wax which might be symptomatic of the nature of some of the crude oils in the area

Alterna-tively, it is also possible that the destructive distillation of bitumen to produce pitch produced

paraffins which crystallized from the mixture over time In Syriac, the term alluded to substances

used for mummification In Egypt, resins were used extensively for purposes of embalming up

until the Ptolemaic period, when asphalts gradually came into use

The product muˆmuˆia was used in prescriptions, as early as the 12th century, by the Arabian

physician Al Magor, for the treatment of contusions and wounds Its production soon became

a special industry in the Alexandria The scientist Al-Kazwıˆnıˆ alludes to the healing properties

of muˆmuˆia, and Ibn Al-Baitaˆr gives an account of its source and composition Engelbert Ka¨mpfer

(1651–1716) in his treatise Amoenitates Exoticae gives a detailed account of the gathering of

muˆmuˆia, the different grades and types, and its curative properties in medicine As the supply

of mummies was of course limited, other expedients came into vogue The corpses of slaves

or criminals were filled with asphalt, swathed and artificially aged in the sun This deceptioncontinued for several centuries until in 1564 AD, it was exposed after a journey into Egypt bythe French physician, Guy de la Fontaine, and as a result, this trade became extinct in the 17thcentury

Many other references to bitumen occur throughout the Greek and Roman empires, andfrom then to the Middle Ages early scientists (alchemists) frequently alluded to the use of bitu-men In later times, both Christopher Columbus and Sir Walter Raleigh (depending upon thecountry of origin of the biographer) have been credited with the discovery of the asphalt deposit

on the island of Trinidad and apparently used the material to caulk their ships

The use of petroleum has also been documented in China: as early as 600 BC (Owen,1975), petroleum was encountered when drilling for salt and mention of petroleum as an impurity

in the salt is also noted in documents of the third century AD It is presumed that the petroleumthat contaminated the salt might be similar to that found in Pennsylvania and was, therefore, amore conventional type rather than the heavier type

There was also an interest in the thermal product of petroleum (nafta; naphtha) when it

was discovered that this material could be used as an illuminant and as a supplement to asphaltincendiaries in warfare For example, there are records of the use of mixtures of pitch and/ornaphtha with sulfur as a weapon of war during the Battle of Palatea, Greece, in the year 429

BC (Forbes, 1959) There are references to the use of a liquid material, naft (presumably the volatile fraction of petroleum which we now call naphtha and which is used as a solvent or as

a precursor to gasoline), as an incendiary material during various battles of the pre-Christianera (James and Thorpe, 1994) This is the so-called Greek fire, a precursor and chemical cousin

to napalm

This probably represents the first documented use of the volatile derivatives of petroleumwhich led to a continued interest in petroleum

Greek fire was a viscous liquid that ignited on contact with water and was sprayed from

a pump-like device on to the enemy One can imagine the early users of the fire attempting to

ignite the liquid before hurling it towards the enemy

However, the hazards that can be imagined from such tactics could become very real, andperhaps often fatal, to the users of the Greek fire if any spillage occurred before ejecting the

fire towards the enemy The later technology for the use of Greek fire probably incorporated a

heat-generating chemical such as quicklime (CaO) (Cobb and Goldwhite, 1995) which wassuspended in the liquid and which, when coming into contact with water (to produce [Ca(OH)2]),released heat that was sufficient to cause the liquid to ignite One assumes that the users of thefire were extremely cautious during periods of rain or, if at sea, during periods of turbulentweather

The combustion properties of bitumen (and its fractions) were known in Biblical times.There is reference to these properties (Isaiah, 34 : 9) when it is stated that:

And the stream thereof shall be turned into pitch, and the dust thereof into brimstone, and the land thereof shall become burning pitch.

It shall not be quenched night nor day; the smoke thereof shall go up forever: from generation to generation it shall lie waste; none shall pass through it for ever and for ever.

One might surmise that the effects of the burning bitumen and sulfur (brimstone) were longlasting and quite devastating

Approximately two thousand years ago, Arabian scientists developed methods for the

History and Terminology 7

distillation of petroleum, which were introduced into Europe by way of Spain This representsanother documented use of the volatile derivatives of petroleum which led to a continued interest

in petroleum and its derivatives as medicinal materials and materials for warfare, in addition

to the usual construction materials

The Baku region of northern Persia was also reported (by Marco Polo in 1271–1273) ashaving an established commercial petroleum industry It is believed that the prime interest was

in the kerosene fraction that was then known for its use as an illuminant By inference, it has

to be concluded that the distillation, and perhaps the thermal decomposition, of petroleum wereestablished technologies If not, Polo’s diaries might well have contained a description of thestills or the reactors

In addition, bitumen was investigated in Europe during the Middle Ages (Bauer, 1546,1556), and the separation and properties of bituminous products were thoroughly described.Other investigations continued, leading to a good understanding of the sources and use of thismaterial even before the birth of the modern petroleum industry (Forbes, 1958a,b)

There are also records of the use of petroleum spirit, probably a higher boiling fraction than naphtha that closely resembled the modern-day liquid paraffin, for medicinal purposes

(Figure 1-1) In fact, the so-called liquid paraffin has continued to be prescribed up to moderntimes The naphtha of that time was obtained from shallow wells or by the destructive distillation

of bitumen

Parenthetically, the destructive distillation operation may be likened to modern cokingoperations (Chapter 14) in which the overall objective is to convert the feedstock into distillatesfor use as fuels This particular interest in petroleum and its derivatives continued with an in-creasing interest in nafta (naphtha) because of its aforementioned use as an illuminant and as

a supplement to asphaltic incendiaries for use in warfare (Figure 1-2)

To continue such references is beyond the scope of this book, although they do give aflavor of the developing interest in petroleum However, it is sufficient to note that there aremany other references to the occurrence and use of bitumen or petroleum derivatives up to thebeginning of the modern petroleum industry (Cook and Despard, 1927; Mallowan and Rose,1935; Nellensteyn and Brand, 1936; Mallowan, 1954; Marschner et al., 1978)

2 MODERN PERSPECTIVES

The modern petroleum industry began in 1859 with the discovery and subsequent ization of petroleum in Pennsylvania (Bell, 1945) After completion of the first well (by EdwinDrake), the surrounding areas were immediately leased and extensive drilling took place Crudeoil output in the United States increased from approximately 2000 barrels (1 barrel, bbl⫽ 42

commercial-U.S gallons⫽ 35 Imperial gallons ⫽ 5.61 foot3⫽ 158.8 liters) in 1859 to nearly 3,000,000

bbl in 1863 and approximately 10,000,000 bbl in 1874 In 1861 the first cargo of oil, contained

in wooden barrels, was sent across the Atlantic to London, and by the 1870s, refineries, tankcars, and pipelines had become characteristic features of the industry Throughout the remainder

of the nineteenth century the United States and Russia were the two areas in which the moststriking developments took place

At the outbreak of World War I in 1914, the two major producers were the United Statesand Russia, but supplies of oil were also being obtained from Indonesia, Rumania, and Mexico.During the 1920s and 1930s, attention was also focused on other areas for oil production, such

as the United States, the Middle East, and Indonesia At this time European and African countrieswere not considered major oil-producing areas In the post-1945 era Middle Eastern countriescontinued to rise in importance because of new discoveries of vast reserves The United States,

Figure 1-1 Representation from an old text of the use of a petroleum derivative as a medication.

Figure 1-2 Representation from an old text of the use of a petroleum derivative as a flammable weapon

History and Terminology 9

Table 1-2 Petroleum and Derivatives, Such as Asphalt, Have Been Known and Used for

Almost 6000 Years

although continuing to be the biggest producer, was also the major consumer and thus was not

a major exporter of oil At this time, oil companies began to roam much farther in the searchfor oil, and significant discoveries in Europe, Africa, and Canada thus resulted

In summary, the use of petroleum and related materials has been observed for almost

6000 years (Table 1-2) During this time, the use of petroleum has progressed from the relativelysimple use of asphalt from Mesopotamian seepage sites to the present-day refining operationsthat yield a wide variety of products (Chapter 21) and petrochemicals (Chapter 23)

However, what is more pertinent to the industry is that throughout the millennia in whichpetroleum has been known and used, it is only in the last decade or so that some attempts havebeen made to standardize the nomenclature and terminology But confusion may still exist.Therefore it is the purpose of this chapter to provide some semblance of order into the disordered

state that exists in the segment of petroleum technology that is known as terminology.

3 DEFINITIONS AND TERMINOLOGY

Terminology is the means by which various subjects are named so that reference can be made

in conversations and in writings and so that the meaning is passed on

Definitions are the means by which scientists and engineers communicate the nature of a

material to each other and to the world, through either the spoken or the written word Thusthe definition of a material can be extremely important and have a profound influence on howthe technical community and the public perceive that material

The definition of petroleum has been varied, unsystematic, diverse, and often archaic.

Furthermore, the terminology of petroleum is a product of many years of growth Thus the established use of an expression, however inadequate it may be, is altered with difficulty, and

long-a new term, however precise, is long-at best long-adopted only slowly

Because of the need for a thorough understanding of petroleum and the associated ogies, it is essential that the definitions and the terminology of petroleum science and technology

technol-be given prime consideration This will aid in a technol-better understanding of petroleum, its uents, and its various fractions Of the many forms of terminology that have been used not allhave survived, but the more commonly used are illustrated here Particularly troublesome, andmore confusing, are those terms that are applied to the more viscous materials, for example the

constit-use of the terms bitumen and asphalt This part of the text attempts to alleviate much of the

confusion that exists, but it must be remembered that the terminology of petroleum is still open

to personal choice and historical usage

Petroleum is a mixture of gaseous, liquid, and solid hydrocarbon compounds that occur

in sedimentary rock deposits throughout the world and also contains small quantities of gen-, oxygen-, and sulfur-containing compounds as well as trace amounts of metallic constit-uents (Bestougeff, 1967; Colombo, 1967; Thornton, 1977; Speight, 1991)

nitro-Petroleum is a naturally occurring mixture of hydrocarbons, generally in a liquid state,which may also include compounds of sulfur nitrogen oxygen metals and other elements (ASTM,1995) Petroleum has also been defined (ITAA, 1936) as:

1 any naturally occurring hydrocarbon, whether in a liquid, gaseous or solid state;

2 any naturally occurring mixture of hydrocarbons, whether in a liquid, gaseous or solidstate; or

3 any naturally occurring mixture of one or more hydrocarbons, whether in a liquid,gaseous or solid state and one or more of the following, that is to say, hydrogensulfide, helium, and carbon dioxide

The definition also includes any petroleum as defined by paragraph (1), (2) or (3) that has beenreturned to a natural reservoir

In the crude state petroleum has minimal value, but when refined it provides high-valueliquid fuels, solvents, lubricants, and many other products (Purdy, 1957) The fuels derived frompetroleum contribute approximately one-third to one-half of the total world energy supply andare used not only for transportation fuels (i.e., gasoline, diesel fuel, and aviation fuel, amongothers) but also to heat buildings Petroleum products have a wide variety of uses that varyfrom gaseous and liquid fuels to near-solid machinery lubricants In addition, the residue of manyrefinery processes, asphalt—a once-maligned by-product—is now a premium value product forhighway surfaces, roofing materials, and miscellaneous waterproofing uses

Crude petroleum is a mixture of compounds boiling at different temperatures that can beseparated into a variety of different generic fractions by distillation (Table 1-3) And the termi-nology of these fractions has been bound by utility and often bears little relationship to compo-sition

History and Terminology 11

Table 1-3 Crude Petroleum: A Mixture of

Compounds That Can Be Separated into

Different Generic Boiling Fractions

The molecular boundaries of petroleum cover a wide range of boiling points and carbonnumbers of hydrocarbon compounds and other compounds containing nitrogen, oxygen, andsulfur, as well as metallic (porphyrinic) constituents However, the actual boundaries of such

a petroleum map can only be arbitrarily defined in terms of boiling point and carbon number

(Figure 1-3) In fact, petroleum is so diverse that materials from different sources exhibit ent boundary limits, and for this reason alone it is not surprising that petroleum has been difficult

differ-to map (Chapter 7) in a precise manner.

Since there is a wide variation in the properties of crude petroleum (Table 1-4), the tions in which the different constituents occur vary with origin (Gruse and Stevens, 1960; Kootsand Speight, 1975) Thus, some crude oils have higher proportions of the lower boiling compo-nents and others (such as heavy oil and bitumen) have higher proportions of higher boilingcomponents (asphaltic components and residuum)

propor-For the purposes of terminology, it is preferable to subdivide petroleum and related als into three major classes (Table 1-5):

materi-1 materials that are of natural origin;

2 materials that are manufactured; and

3 materials that are integral fractions derived from the natural or manufactured products

4 NATIVE MATERIALS

4.1 Petroleum

Petroleum and the equivalent term crude oil, cover a wide assortment of materials consisting

of mixtures of hydrocarbons and other compounds containing variable amounts of sulfur, gen, and oxygen, which may vary widely in volatility, specific gravity, and viscosity Metal-containing constituents, notably those compounds that contain vanadium and nickel, usuallyoccur in the more viscous crude oils in amounts up to several thousand parts per million andcan have serious consequences during processing of these feedstocks (Gruse and Stevens, 1960;

nitro-Figure 1-3 The physical boundaries for petroleum can be arbitrarily defined using carbon number andboiling point data () Known boiling point ( ) Hypothetical boiling point.

Table 1-4 Wide Variation in the Properties of Different Crude Petroleums

History and Terminology 13

Table 1-5 Petroleum and Related Materials Can Be Divided

into Various Class Subgroupsa

a Tar sand is a misnomer; tar is a product of coal processing Bituminous

sands is more correct Oil sands is also a misnomer but is equivalent to

usage of ‘‘oil shale.’’

b The nonvolatile portion of petroleum, often further defined as

‘‘at-mospheric’’ (bp ⬎ 350°C; ⬎ 660°F) or ‘‘vacuum’’ (bp ⬎ 565°C;

⬎ 1050°F).

c A product of a refinery operation, usually made from a residuum.

Speight, 1984) Because petroleum is a mixture of widely varying constituents and proportions,its physical properties also vary widely (Chapter 8) and the color from colorless to black.Petroleum occurs underground, at various pressures depending on the depth Because ofthe pressure, it contains considerable natural gas in solution The oil underground is much morefluid than it is on the surface and is generally mobile under reservoir conditions because theelevated temperatures in subterranean formations (on the average, the temperature rises 1°C for

every 100 ft, 33 meters, of depth) decrease the viscosity

Petroleum is derived from aquatic plants and animals that lived and died hundreds ofmillions of years ago Their remains mixed with mud and sand in layered deposits that, over themillennia, were geologically transformed into sedimentary rock Gradually the organic matterdecomposed and eventually formed petroleum (or a related precursor), which migrated from

the original source beds to more porous and permeable rocks, such as sandstone and siltstone, where it finally became entrapped Such entrapped accumulations of petroleum are called reser-

voirs A series of reservoirs within a common rock structure or a series of reservoirs in separate

but neighboring formations is commonly referred to as an oil field A group of fields is often found in a single geologic environment known as a sedimentary basin or province.

The major components of petroleum (Chapter 6) are hydrocarbons, compounds of

hydro-gen and carbon that display great variation in their molecular structure The simplest

hydrocar-bons are a large group of chain-shaped molecules known as the paraffins This broad series

extends from methane, which forms natural gas, through liquids that are refined into gasoline,

to crystalline waxes A series of ring-shaped hydrocarbons, known as the naphthenes, ranges from volatile liquids such as naphtha to high molecular weight substances isolated as the asphal-

tene fraction Another group of ring-shaped hydrocarbons is known as the aromatics; the chief

compound in this series is benzene, a popular raw material for making petrochemicals

Nonhydrocarbon constituents of petroleum include organic derivatives of nitrogen,

oxy-gen, sulfur, and the metals nickel and vanadium Most of these impurities are removed duringrefining.

Geologic techniques (Chapter 5) can determine only the existence of rock formations thatare favorable for oil deposits, not whether oil is actually there Drilling is the only sure way toascertain the presence of oil With modern rotary equipment, wells can be drilled to depths ofmore than 30,000 feet (9,000 m) Once oil is found, it may be recovered (brought to the surface)

by the pressure created by natural gas or water within the reservoir Crude oil can also be brought

to the surface by injecting water or steam into the reservoir to raise the pressure artificially, or

by injecting such substances as carbon dioxide, polymers, and solvents to reduce crude oilviscosity Thermal recovery methods are frequently used to enhance the production of heavycrude oils, whose extraction is impeded by viscous resistance to flow at reservoir temperatures.Crude oil is transported to refineries by pipelines, which can often carry more than 500,000barrels per day, or by ocean-going tankers The basic refinery process is distillation, whichseparates the crude oil into fractions of differing volatility After the distillation, other physicalmethods are employed to separate the mixtures, including absorption, adsorption, solvent extrac-tion, and crystallization After physical separation into such constituents as light and heavynaphthas, kerosene, and light and heavy gas oils, selected petroleum fractions may be subjected

to conversion processes, such as cracking (Chapters 14 and 15) In the most general terms,cracking breaks the large molecules of heavier gas oils into the smaller molecules that form thelighter, more valuable naphtha fractions

Reforming (Chapter 18) changes the structure of straight-chain paraffin molecules into

branched-chain iso-paraffins and ring-shaped aromatics The process is widely used to raise the

octane number of gasoline obtained by distillation of paraffinic crude oils

4.2 Heavy Oil

There are also other types of petroleum that are different from the conventional petroleum insofar

as they are much more difficult to recover from the subsurface reservoir These materials have

a much higher viscosity (and lower API gravity) than conventional petroleum, and primaryrecovery of these petroleum types usually requires thermal stimulation of the reservoir (Chap-ter 5)

When petroleum occurs in a reservoir in a form that allows the crude material to berecovered by pumping operations as a free-flowing dark to light colored liquid, it is often referred

to as conventional petroleum.

Heavy oils are the other types of petroleum that are different from conventional petroleum

insofar as they are much more difficult to recover from the subsurface reservoir The definition

of heavy oils is usually based on the API gravity or viscosity, and the definition is quite arbitraryalthough there have been attempts to rationalize the definition based upon viscosity, API gravity,and density

For many years, petroleum and heavy oil were very generally defined in terms of physicalproperties For example, heavy oils were considered to be those crude oils that had gravitysomewhat less than 20° API with the heavy oils falling into the API gravity range 10–15° For

example, Cold Lake heavy crude oil has an API gravity equal to 12° and extra heavy oils, such

as tar sand bitumen, usually have an API gravity in the range 5–10° (Athabasca bitumen ⫽ 8°

API) Residua would vary depending upon the temperature at which distillation was terminatedbut usually vacuum residua were in the range 2–8° API

Heavy oils have a much higher viscosity (and lower API gravity) than conventional leum, and primary recovery of these petroleum types usually requires thermal stimulation of

petro-the reservoir The generic term heavy oil is often applied to a crude oil that has less than 20°

History and Terminology 15

API and usually, but not always, a sulfur content higher than 2% by weight (Speight, 1981).Furthermore, in contrast to conventional crude oils, heavy oils are darker in color and may even

be black

The term heavy oil has also been arbitrarily used to describe both the heavy oils that

require thermal stimulation of recovery from the reservoir and the bitumen in bituminous sand

(tar sand, q.v.) formations from which the heavy bituminous material is recovered by a mining

operation

Extra heavy oils are materials that occur in the solid or near-solid state and are generally

incapable of free flow under ambient conditions (bitumen, q.v.).

4.3 Bitumen

The term bitumen (also, on occasion, referred to as native asphalt, and extra heavy oil ) includes

a wide variety of reddish brown to black materials of semisolid, viscous to brittle character thatcan exist in nature with no mineral impurity or with mineral matter contents that exceed 50%

by weight Bitumen is frequently found filling pores and crevices of sandstone, limestone, orargillaceous sediments, in which case the organic and associated mineral matrix is known as

rock asphalt (Abraham, 1945; Hoiberg, 1964).

Bitumen is a naturally-occurring material that is found in deposits where the permeability

is low and passage of fluids through the deposit can only be achieved by prior application offracturing techniques Tar sand bitumen is a high-boiling material with little, if any, materialboiling below 350°C (660°F) and the boiling range approximates the boiling range of an atmo-

spheric residuum

Tar sands have been defined in the United States (FE-76-4) as:

the several rock types that contain an extremely viscous hydrocarbon which is not recoverable in its natural state by conventional oil well production methods including cur- rently used enhanced recovery techniques The hydrocarbon-bearing rocks are variously known as bitumen-rocks oil, impregnated rocks, oil sands, and rock asphalt.

The recovery of the bitumen depends to a large degree on the composition and construction

of the sands Generally, the bitumen found in tar sand deposits is an extremely viscous material

that is immobile under reservoir conditions and cannot be recovered through a well by the

application of secondary or enhanced recovery techniques The bitumen in tar sand formationsrequires a high degree of thermal stimulation for recovery to the extent that some thermal decom-position may have to be induced Current recovery operations of bitumen in tar sand formationsinvolve use of a mining technique (Chapter 5)

The expression tar sand is commonly used in the petroleum industry to describe sandstone

reservoirs that are impregnated with a heavy, viscous black crude oil that cannot be retrieved

through a well by conventional production techniques However, the term tar sand is actually

a misnomer and it is incorrect to refer to native bituminous materials as tar or pitch Although

the word tar is descriptive of the black, heavy bituminous material, it is best to avoid its usewith respect to natural materials and to restrict the meaning to the volatile or near-volatileproducts produced in the destructive distillation of such organic substances as coal (Speight,

1980, 1983) In the simplest sense, pitch is the distillation residue of the various types of tar

Thus, alternative names, such as bituminous sand or oil sand, are gradually finding usage, with the former name (bituminous sands) more technically correct The term oil sand is also used in the same way as the term tar sand, and these terms are used interchangeably throughout

this text

However, in order to define bitumen, heavy oil, and conventional petroleum, the use of

a single physical parameter such as viscosity is not sufficient Other properties such as APIgravity, elemental analysis, composition, and, most of all, the properties of the bulk depositmust also be included in any definition of these materials Only then will it be possible to classifypetroleum and its derivatives (Chapter 2).

4.4 Wax

Naturally-occurring wax, often referred to as mineral wax, occurs as yellow to dark brown,

solid substances and are composed largely of paraffins (Wollrab and Streibl, 1969) Fusionpoints vary from 60°C (140°F) to as high as 95°C (203°F) They are usually found associated

with considerable mineral matter, as a filling in veins and fissures or as an interstitial material

in porous rocks The similarity in character of these native products is substantiated by the

fact that, with minor exceptions where local names have prevailed, the original term ozokerite (ozocerite) has served without notable ambiguity for mineral wax deposits (Gruse and Stevens,

1960)

Ozokerite (ozocerite), from the Greek meaning odoriferous wax, is a naturally occurring

hydrocarbon material composed chiefly of solid paraffins and cycloparaffins (i.e., hydrocarbons)(Wollrab and Streibl, 1969) Ozocerite usually occurs as stringers and veins that fill rock frac-tures in tectonically disturbed areas It is predominantly paraffinic material (containing up to

90 percent nonaromatic hydrocarbons) with a high content (40–50 percent) of normal or slightlybranched paraffins as well as cyclic paraffin derivatives Ozocerite contains approximately 85%carbon, 14% hydrogen, and 0.3% each of sulfur and nitrogen and is, therefore, predominantly

a mixture of pure hydrocarbons; any nonhydrocarbon constituents are in the minority.Ozocerite is soluble in solvents that are commonly employed for dissolution of petroleumderivatives, e.g., toluene, benzene, carbon disulfide, chloroform, and ethyl ether

In the present context, note that the term migrabitumen signifies secondary bitumen

(sec-ondary macerals) generated from fossil organic material during diagenesis and catagenesis(Chapter 3) These materials are usually amorphous solids and can be classified into severalsubgroups (Chapter 3)

4.5 Asphaltite

Asphaltites are a variety of naturally occurring, dark brown to black, solid, nonvolatile

bitumi-nous substances that are differentiated from bitumen primarily by their high content of material

insoluble in the common organic solvents and high yields of thermal coke (Yurum and Ekinci,1995) The resultant high temperature of fusion (approximate range 115–330°C, 240–625°F)

is characteristic The names applied to the two rather distinct types included in this group arenow accepted and used for the most part without ambiguity

Gilsonite was originally known as uintaite from its discovery in the Uinta Basin of western

Colorado and eastern Utah It is characterized by a bright luster and a carbon residue in therange 10–20% by weight The mineral occurs in nearly vertical veins varying from about aninch to many feet in width and is relatively free of occluded inorganic matter Samples takenfrom different veins and across the larger veins may vary somewhat in softening point, solubilitycharacteristics, sulfur content, and so on, but the variation is not great It is evident in all instancesthat it is essentially the same material, and it is therefore appropriate to apply a single name tothis mineral However, caution should be exercised in using the same term without qualification

for similar materials until it can be shown that they are equivalent to gilsonite.

The second recognized type in this category is grahamite, which is very much like

gilson-ite in external characteristics but is distinguished from the latter by its black streak, relatively

History and Terminology 17

high fixed carbon value (35–55%), and high temperature of fusion, which is accompanied by

a characteristic intumescence The undifferentiated term grahamite must be used with caution;

similarities in the characteristics of samples from different areas do not necessarily imply anychemical or genetic relationship

A third but rather broad category of asphaltites includes a group of bituminous materials

known as glance pitch, which physically resemble gilsonite but have some of the properties of

grahamite They have been referred to as intermediates between the two, although the possibility

exists that they are basically different from gilsonite and may represent something between

bitumen and grahamite.

4.6 Asphaltoid

Asphaltoids are a further group of brown to black, solid bituminous materials of which the

members are differentiated from the asphaltites by their infusibility and low solubility in carbon disulfide These substances have also been designated asphaltic pyrobitumens, as they decom- pose on heating into bitumen-like materials However, the term pyrobitumen does not convey the impression intended; thus the members of this class are referred to as asphaltoids since they

closely resemble the asphaltites

Pyrobitumen, is a naturally occurring solid organic substance that is distinguishable from

bitumen (q.v.) by being infusible and insoluble When heated, however, pyrobitumen generates,

or transform into, bitumen-like liquid and gaseous hydrocarbon compounds Pyrobitumens may

be either asphaltic or nonasphaltic The asphaltic pyrobitumens are derived from petroleum, arerelatively hard, and have a specific gravity below 1.25 They do not melt when heated but swell

and decompose (intumesce).

There is much confusion regarding the classification of asphaltoids, although four types

are recognized: elaterite, wurtzilite, albertite, and impsonite—in order of increasing density

and fixed carbon content In fact, it is doubtful that the asphaltoid group can ever be clearlydifferentiated from the asphaltites It is even more doubtful that the present subdivisions willever have any real meaning, nor is it clear that the materials have any necessary genetic connec-tion Again, caution should be exercised in the use of the names, and due care should be applied

to qualification of the particular sample

4.7 Bituminous Rock and Bituminous Sand

Bituminous rock and bituminous sand are those formations in which the bituminous material is

found as a filling in veins and fissures in fractured rocks or impregnating relatively shallowsand, sandstone, and limestone strata The deposits contain as much as 20% bituminous material,and if the organic material in the rock matrix is bitumen, it is usual (although chemically incor-

rect) to refer to the deposit as rock asphalt to distinguish it from bitumen that is relatively

mineral free A standard test (ASTM D-4) is available for determining the bitumen content of

various mixtures with inorganic materials, although the use of the word bitumen as applied in this test might be questioned and it might be more appropriate to use the term organic residues

to include tar and pitch.

If the material is of the asphaltite-type or asphaltoid-type, the corresponding terms should

be used: rock asphaltite or rock asphaltoid (Speight, 1980)

Bituminous rocks generally have a coarse, porous structure, with the bituminous material

in the voids A much more common situation is that in which the organic material is present

as an inherent part of the rock composition insofar as it is a diagenetic residue of the organic

material detritus that was deposited with the sediment The organic components of such rocksare usually refractory and are only slightly affected by most organic solvents.

A special class of bituminous rocks that has achieved some importance is the so-called

oil shales These are argillaceous, laminated sediments of generally high organic content that

can be thermally decomposed to yield appreciable amounts of oil, commonly referred to as

shale oil Oil shale does not yield shale oil without the application of high temperatures and

the ensuing thermal decomposition that is necessary to decompose the organic material (kerogen)

in the shale

Sapropel is an unconsolidated sedimentary deposit rich in bituminous substances It is

distinguished from peat in being rich in fatty and waxy substances and poor in cellulosic rial When consolidated into rock, sapropel becomes oil shale, bituminous shale, or bogheadcoal The principal components are certain types of algae that are rich in fats and waxes Minorconstituents are mineral grains and decomposed fragments of spores, fungi, and bacteria Theorganic materials accumulate in water under reducing conditions

mate-4.8 Kerogen

Kerogen is the complex carbonaceous (organic) material that occurs in sedimentary rocks and

shales It is for the most part insoluble in the common organic solvents When the kerogen

occurs in shale, the whole material is often referred to as oil shale This, like the term oil sand,

is a misnomer insofar as the shale does not contain oil; oil sand (like the more correct term

bituminous sand implies) contains a viscous nonvolatile material that can be isolated without

thermal decomposition A synthetic crude oil is produced from oil shale by the application of

heat so that the kerogen is thermally decomposed (cracked) to produce the lower molecularweight products Kerogen is also reputed to be a precursor of petroleum (Chapter 4)

For comparison with tar sand, oil shale is any fine-grained sedimentary rock containing solid organic matter (kerogen; q.v.) that yields oil when heated (Scouten, 1990) Oil shales vary

in their mineral composition For example, clay minerals predominate in true shales, while otherminerals (e.g., dolomite and calcite) occur in appreciable but subordinate amounts in the carbon-ates In all shale types, layers of the constituent mineral alternate with layers of kerogen

4.9 Natural Gas

The generic term natural gas applies to gases commonly associated with petroliferous

(petro-leum-producing, petroleum-containing) geologic formations Natural gas generally contains highproportions of methane (a single carbon hydrocarbon compound, CH4) and some of the highermolecular weight higher paraffins (CnH2n ⫹2) generally containing up to six carbon atoms mayalso be present in small quantities The hydrocarbon constituents of natural gas are combustible,but nonflammable nonhydrocarbon components such as carbon dioxide, nitrogen, and heliumare often present in the minority and are regarded as contaminants

In addition to the natural gas found in petroleum reservoirs, there are also those reservoirs

in which natural gas may be the sole occupant The principal constituent of natural gas is ane, but other hydrocarbons, such as ethane, propane, and butane, may also be present Carbondioxide is also a common constituent of natural gas Trace amounts of rare gases, such as helium,may also occur, and certain natural gas reservoirs are a source of these rare gases Just aspetroleum can vary in composition, so can natural gas Differences in natural gas compositionoccur between different reservoirs, and two wells in the same field may also yield gaseousproducts that are different in composition (Speight, 1990)

meth-Natural gas has been known for many centuries, but its initial use was probably more for

History and Terminology 19

religious purposes rather than as a fuel For example, gas wells were an important aspect ofreligious life in ancient Persia because of the importance of fire in their religion In classicaltimes these wells were often flared and must have been, to say the least, awe inspiring (Lockhart,1939; Forbes, 1964)

There is also the possibility that the voices of the gods recorded by the ancients were

actually natural gas forcing its way through fissures in the earth’s surface (Scheil and Gauthier,1909; Schroder, 1920) Gas wells were also known in Europe in the Middle Ages, and oil wasreportedly ejected from the wells, as in the phenomena observed at the site near the town ofMineo, Sicily From other such documentation, it can be surmised that the combustible material,

or the source of the noises in the earth, was actually natural gas

Just as petroleum was used in antiquity, natural gas was also known in antiquity However,the use of petroleum has been relatively well documented because of its use in warfare and as

a mastic for walls and roads (Table 1-2) The use of natural gas in antiquity is somewhat lesswell documented, although historical records indicate that the use of natural gas (for other thanreligious purposes) dates back to about 250 AD when it was used as a fuel in China The gaswas obtained from shallow wells and was distributed through a piping system constructed fromhollow bamboo stems There is other fragmentary evidence for the use of natural gas in certainold texts, but the use is usually inferred since the gas is not named specifically However, it isknown that natural gas was used on a small scale for heating and lighting in northern Italyduring the early seventeenth century From this it might be conjectured that natural gas foundsome use from the seventeenth century to the present day, recognizing that gas from coal would

be a strong competitor

Natural gas was first discovered in the United States in Fredonia, New York, in 1821 Inthe years following this discovery, natural gas usage was restricted to its environs since thetechnology for storage and transportation (bamboo pipes notwithstanding) was not well devel-oped and, at that time, natural gas had little or no commercial value In fact, in the 1930s whenpetroleum refining was commencing an expansion in technology that is still continuing, naturalgas was not considered a major fuel source and was only produced as an unwanted by-product

of crude oil production

The principal gaseous fuel source at that time (i.e., the 1930s) was the gas produced bythe surface gasification of coal In fact, each town of any size had a plant for the gasification

of coal (hence the use of the term town gas) Most of the natural gas produced at the petroleum

fields was vented to the air or burned in a flare stack; only a small amount of the natural gasfrom the petroleum fields was pipelined to industrial areas for commercial use It was only inthe years after World War II that natural gas became a popular fuel commodity, leading to therecognition that it has at the present time

There are several general definitions that have been applied to natural gas Thus, lean gas

is gas in which methane is the major constituent Wet gas contains considerable amounts of the higher molecular weight hydrocarbons Sour gas which contains hydrogen sulfide whereas sweet gas contains very little, if any, hydrogen sulfide Residue gas is natural gas from which the higher molecular weight hydrocarbons have been extracted and casinghead gas is derived from

petroleum but is separated at the separation facility at the well-head

To further define the terms dry and wet in quantitative measures, the term dry natural gas

indicates that there is less than 0.1 gallon (1 gallon, U.S.,⫽ 0.00379 m3) of gasoline vapor(higher molecular weight paraffins) per 1000 ft3(1 ft3⫽ 0.028 m3) The term wet natural gas

indicates that there are such paraffins present in the gas, in fact more than 0.1 gal/1000 ft3

Associated or dissolved natural gas occurs either as free gas or as gas in solution in the

petroleum Gas that occurs as a solution in the petroleum is dissolved gas whereas the gas that exists in contact with the petroleum (gas cap) is associated gas.

Other components such as carbon dioxide (CO2), hydrogen sulfide (H2S), mercaptans ols; R-SH), as well as trace amounts of other constituents may also be present Thus, there is

(thi-no single composition of components which might be termed typical natural gas Methane and

ethane constitute the bulk of the combustible components; carbon dioxide (CO2) and nitrogen(N2) are the major noncombustible (inert) components

5 MANUFACTURED MATERIALS

5.1 Wax

The term paraffin wax is restricted to the colorless, translucent, highly crystalline material

ob-tained from the light lubricating fractions of paraffinic crude oils (wax distillates) The cial products melt in the approximate range of 50–65°C (120–150°F) Dewaxing of heavier

commer-fractions leads to semisolid material, generally known as petrolatum, and solvent de-oiling of

the petroleum or of heavy, waxy residua results in dark-colored waxes of a sticky, plastic to

hard nature The waxes are composed of fine crystals and contain, in addition to n-paraffins, appreciable amounts of iso-paraffins and cyclic hydrocarbon compounds substituted with long-

chain alkyl groups The melting points of the commercial grades are in the 70–90°C (160–

195°F) range (Brooks et al., 1938)

Highly paraffinic waxes are also produced from peat, lignite, or shale oil residua, and

paraffin waxes known as ceresins, which are quite similar to the waxes from petroleum, may also be prepared from ozokerite (q.v.).

5.2 Residuum (Residua)

A residuum ( pl residua, also shortened to resid, pl resids) is the residue obtained from

petro-leum after nondestructive distillation has removed all the volatile materials The temperature

of the distillation is usually maintained below 350°C (660°F) since the rate of thermal

decompo-sition of petroleum constituents is minimal below this temperature but the rate of thermal position of petroleum constituents is substantial above 350°C (660°F) (Figure 1-4)

decom-Residua are black, viscous materials and are obtained by distillation of a crude oil under

atmospheric pressure (atmospheric residuum) or under reduced pressure (vacuum residuum)(Figure 1-5) They may be liquid at room temperature (generally atmospheric residua) or almostsolid (generally vacuum residua) depending upon the nature of the crude oil (Tables 1-6 and1-7; Figure 1-6)

When a residuum is obtained from a crude oil and thermal decomposition has commenced,

it is more usual to refer to this product as pitch The differences between a parent petroleum and

the residua are due to the relative amounts of various constituents present, which are removed orremain by virtue of their relative volatility (Figure 1-7)

The chemical composition of a residuum from crude oil is complex Physical methods offractionation usually indicate high proportions of asphaltenes and resins, even in amounts up to50% (or higher) of the residuum In addition, the presence of ash-forming metallic constituents,including such organometallic compounds as those of vanadium and nickel, is also a distinguish-

ing feature of residua and the heavier oils Furthermore, the deeper the cut into the crude oil,

the greater is the concentration of sulfur and metals in the residuum and the greater the tion in physical properties (Table 1-7; Figures 1-8, 1-9, and 1-10)

deteriora-5.3 Asphalt

Asphalt is manufactured from petroleum (Figure 1-11) black or brown material that has a

consis-tency varying from a viscous liquid to a glassy solid To a point, asphalt can resemble bitumen,

History and Terminology 21

Figure 1-4 Variation in the rate of decomposition of petroleum constituents with temperature

Figure 1-5 Residua are obtained by removal of the volatile constituents of the feedstock at atmosphericpressure or at reduced pressure, but the properties of the residua differ considerably with the ‘‘end point’’(see Table 1-5)