ASSESSMENT OF GASOLINE TOXICITY
PEDCo ENVIRONMENTAL
-------
PEDCo ENVIRONMENTAL
11499 CHESTER ROAD
CINCINNATI. OHIO 45246
(513) 7S2-47OO
ASSESSMENT OF GASOLINE TOXICITY
Prepared by
PEDCo Environmental, Inc.
11499 Chester Road
Cincinnati, Ohio 45246
Contract No. 68-02-2515
Task No. 12
EPA Task Officer: Richard Johnson
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Strategies and Air Standards Division
Research Triangle Park,
North Carolina 27711
October 1977
BRANCH OFFICES
CHESTER TOWERS
Crown Center
Kansas City. Mo.
Professional Village
Chapel HIM. ISI.C.
-------
. This report was furnished to the U.S. Environmental
Protection Agency by PEDCo Environmental, Inc. Cincinnati,
Ohio, in fulfillment of Contract No. 68-02-2515, Task No. 12,
The contents are reproduced herein as received from the
contractor. The opinions, findings, and conclusions
expressed are those of the authors and not necessarily those
of the Environmental Protection Agency.
ii
-------
ACKNOWLEDGMENT
This report was .furnished to the U.S. Environmental
Protection Agency by PEDCo Environmental, Inc. Cincinnati,
Ohio. Terry Briggs was the PEDCo Project Manager and
George Jutze functioned as Service Director. Principal
authors of the report were Terry Briggs and Mark Karaffa.
Richard Johnson was the Task Officer for the U.S. Environ-
mental Protection Agency.
111
-------
TABLE OF CONTENTS
Page
1.0 SUMMARY 1-1
2.0 INTRODUCTION 2-1
2.1 Refinery Process Description 2-2
3.0 GASOLINE COMPOSITION 3-1
3.1 Component Analysis of Gasoline 3-1
3.2 Gasoline Vapor Analysis 3-30
4.0 GASOLINE TOXICITY EVALUATION 4-1
4.1 Gasoline Component Toxicity 4-2
4.2 Gasoline Toxicity Studies 4-17
4.3 Epidemiology and Exposure Studies 4-25
5.0 GASOLINE VAPOR CONTROL TECHNOLOGY 5-1
5.1 Reduction of Toxic Components Versus 5-1
Total Hydrocarbons in Gasoline
APPENDIX A GASOLINE LOADING TERMINAL VAPOR EMISSIONS A-l
IV
-------
LIST OF FIGURES
No. - Page
2-1. Typical Integrated Refinery Processing Plan 2-4
3-1 Distillation Curve for Typical Gasoline 3-3
3-2 Sensitivity of Displaced Loss to Temperature 3-35
at Various Values of RVP
3-3 Hydrocarbon Vapor Composition in Underground 3-36
Tank
4-1 Calculated Gasoline Threshold Limit Value, 4-33
Reflecting Impact of Present vs. Proposed
Benzene TLV Standard as a Function of the Liquid
Volume Percent Benzene in the Gasoline
LIST OF TABLES
No. Page
1-1 Average Gasoline Vapor Composition 1-3
2-1 Summary of Major Refinery Processing Units 2-8
3-1 Typical Gasoline Specifications 3-2
3-2 Summary of Values, Motor Gasoline Survey 3-4
3-3 Motor Gasoline Survey, Winter 1976-77 Average 3-6
Data for Brands in Each District
3-4 Gasoline Blending Summary 3-7
3-5 Gasoline Grade Requirements by Percent 3-9
3-6 Major Refinery Gasoline Blending Components 3-11
3-7 Reforming Feed and Product Data 3-12
3-8 Analysis of Reformate Aromatics 3-10
3-9 Cat Cracking Yield Characteristics 3-14
v
-------
LIST OF TABLES (continued).
No. Page
3-10 Cat Naphtha Component Analysis 3-15
3-11 Alkylate Properties 3-17
3-12 Hydrocracking Yield Data 3-18
3-13 Trace Elements in Gasoline 3-22
3-14 Gasoline Composition Summary Data Reported as 3-23
Weight Percent
3-15 Detailed Gasoline Component Analysis 3-24
3-16 Hydrocarbon Composition of Los Angeles Gasolines 3-27
3-17 Benzene Content of Gasoline Blending Components 3-28
3-18 Octane Rating of Alkanes as a Function of 3-30
Molecular Structure
3-19 Approximate Gasoline Vapor Components 3-32
3-20 Seasonal Compositions of Gasoline and its Vapors 3-33
in Mole Percent
3-21 Example Gasoline Vapor Compositions 3-34
3-22 Airborne Concentration of Gasoline Additives 3-38
4-1 Effects of Alkane Vapor Exposure on Humans 4-4
4-2 Effects of Alkane Vapor Exposure on Animals 4-5
4-3 Humand Experience: Exposure to Gasoline Vapors 4-22
5-1 Analyses of Hydrocarbon Fractions of Gasoline 5-2
Loading Vapors and Relative Volatility
5-2 Threshold Limit Values, Relative Volatility, and 5-3
Concentrations of Selected Toxic Vapors From
Gasoline Loading Operations
A-l Reid Vapor Pressures A-l
A-2 Gasoline Vapor Concentrations A-l
A-3 Analysis of Air-Vapor Feed to Oxidizer A-2
VI
-------
1.0 SUMMARY
Gasoline storage and handling operations are known to
be major contributors of hydrocarbon emissions in the United
States. Because gasoline contains a wide range of compounds
(some of which are known to be toxic), the purpose of this
report is to provide information needed to assess the
toxicity of gasoline vapors and to describe major variables
affecting the composition of gasoline and gasoline blending
components.
Gasoline normally contains over 200 hydrocarbon com-
pounds, mainly in the C5 to Cg fraction, with a boiling
range of 26° to 204°C (80° to 400°F). Alkanes and aromatics
generally constitute the largest fraction, but olefins and
naphthenes are also present. Gasoline also contains a
variety of additives for improving engine performance. Lead
alkyls easily represent the major additive in leaded gaso-
lines.
The composition of gasoline (and consequently its
vapor) varies as a function of the crude oil, the refinery
process, the gasoline blending makeup for different grades,
the particular grade of gasoline, and the climate of the
marketing region. Crude oils vary in aromatics content;
thus, gasoline varies in aromatics content. Because each
gasoline blending stock has a characteristic composition
range, the refinery processing units, their relative sizes,
and the blending scheme for the different grades all affect
the composition of each gasoline grade. Octane rating
varies primarily as a function of gasoline grade. Since
1-1
-------
alkyl lead additives increase gasoline octane ratings, lower
octane blending stocks can be used in the production of a
given leaded gasoline. The octane rating of unleaded gaso-
line, however, depends solely on the natural octane rating
of its ble'nding components.
The major gasoline blending stocks are catalytically
cracked (cat-cracked) gasoline; reformate; alkylate; light,
straight-run gasoline; hydrocracked gasoline; and thermally
cracked gasoline. The highest octane blending components in
gasoline are aromatics and branched-chain paraffins; there-
fore, the refineries attempt to produce blending streams
rich in these components. Reformate and cat-cracked gaso-
line are high in aromatics, whereas alkylate is very high in
paraffins. The increasing demand for unleaded gasoline is
forcing refineries to process more of the lower octane
blending streams such as light, straight-run gasoline;
hydrocracked gasoline; and thermally cracked gasoline.
These processes primarily involve conversion of naphthenes
to .aromatics and normal paraffins to isoparaffins.
Because gasoline vapor is a highly complex mixture of
hydrocarbons and additives in widely varying concentrations,
an accurate assessment of its toxicology is difficult.
(Table 1-1 shows an average composition of gasoline vapor.)
Adding to the difficulty is the limited amount of definitive
toxicological or epidemiological data, particularly with
regard to chronic gasoline intoxication.
Health effects associated with gasoline vapor exposure
are presented here (and in the literature) as a function of
the toxicity of the vapor components, namely, paraffins,
olefins, naphthenes, aromatics, and other additives. Com-
ponents known to produce or suspected of producing carcino-
genic, mutagenic, or other severe systemic effects are
1-2
-------
Table 1-1. AVERAGE GASOLINE VAPOR COMPOSITION
Compound Mean volume
percent
Alkanes
Propane 0.8
N-butane 38.1
I-butane 5.2
I-pentane 22.9
N-pentane 7.0
Cyclopentane 0.7
Dimethylbutane 0.7
Melhylpentanes 3.6
N-hexane 1.5
Methyl cyclopentane 1.3
Dimethyl pentanes 1.1
Trimethyl pentanes 0. 5
Alkenes
I-butylene 1.1
Methyl butenes 2 .8
Aromatics
Benzene 0.7
Tolvene 1.8
Xylene 0.5
1-3
-------
identified. These are regarded as the most significant
toxicologically, and their contribution to the toxicity of
gasoline vapor is assessed on the basis of their individual
toxicities.
. Historically, aromatic hydrocarbons have been con-
sidered the most toxic components in gasoline. Benzene,
because of its volatility, unique myelotoxicity, and car-
cinogenic potential, is considered the most hazardous com-
ponent in the aromatic fraction of gasoline vapor. Toluene,
xylenes, and other alkylated benzene derivations are much
less toxic and volatile than benzene.
Chronic exposure to some alkane components has been
associated with the development of polyneuropathy and other
neurological changes in humans. Also, a lower threshold
level value (TLV) for alkanes has been proposed in occupa-
tional environments. In view of these developments and
because gasoline contains a large proportion of aliphatic
hydrocarbons, the toxic potential of alkane components
should be carefully considered.
Tetraethyl and tetramethyl lead and organic halogen
compounds are added to gasolines to improve performance.
Although these compounds are potentially toxic, it is believed
their contribution to the overall toxicity of gasoline vapor
would be minor because of their chemical characteristics and
minute concentrations. Ethylene dibromide, one of the
organic halogens added to gasoline, has been identified as a
a
carcinogen and is suspected of mutagefaic and teratogenic
action. Its toxicologic significance is particularly diffi-
cult to assess, however, if one maintains that there is no
threshold" level for carcinogens, mutagens, or teratogens.
Olefins and naphthenes lack the biological properties
that would warrant their consideration as environmental
1-4
-------
health hazards. Also, data on chronic inhalation exposures
are insufficient.
Definitive epidemiological or experimental data on
gasoline vapor exposure are limited. The literature con-
sists primarily of descriptive accounts of acute intoxica-
tion and medical reports or general observations following
chronic gasoline inhalation exposure.
Several investigators have attempted to assess gasoline
toxicity as a function of exposure to its most toxic com-
ponent, benzene; but the concept of benzene having an addi-
tive effect with other hydrocarbons is considered a more
realistic approach to the question of gasoline toxicity.
Before this method could be tested and used, however, it
would be necessary to obtain data from comprehensive epidemio-
logical studies that encompass both chemical and environ-
mental parameters or to extrapolate data from carefully
designed and well-controlled animal experiments. Recent
exposure tests on benzene and gasoline vapors have served
only to determine the amounts present in the atmosphere or
the quantities to which employees in a given area are exposed.
No attempt has been made to measure the health risk to the
general public as a result of benzene or gasoline vapor
exposure.
A brief review of gasoline vapor control techniques
indicates that the more toxic constituents can be controlled
more efficiently than overall emissions.
1-5
-------
2.0 INTRODUCTION
The purpose of this report is to provide information
needed to assess the toxicity of gasoline vapors and to
describe major variables affecting the composition of gaso-
line and gasoline blending components.
Gasoline is not only a blend of different hydrocarbons,
it is also a blend of gasoline streams from different
refineries. The quantity and composition of each grade of
gasoline vary according to demand for the grade, type of
crude oil being processed, process units at the refinery
producing a given gasoline, and quality specifications. The
most important quality criterion in the blending of motor
gasoline is that the blend provide good performance in
automotive internal combustion engines and similar equip-
ment.
The main parameters of gasoline blends are volatility
and antiknock performance. Correct volatility (the tendency
for a liquid fuel to evaporate) produces easy starting of
cold engines, good acceleration, and proper fuel distribu-
tion to individual cylinders. Too much volatility can cause
vapor lock, a situation in which gasoline vaporizes in fuel
lines and blocks the flow of liquid gasoline. To achieve
proper volatility, light hydrocarbon compounds such as
butanes and pentanes are blended into the gasoline. These
low boiling compounds remain in solution in the liquid
gasoline and contribute to volatility. Climatic conditions
govern the quantity of the light compounds blended into the
gasoline.
2-1
-------
Antiknock performance refers to the tendency for ping-
ing or "knocking" in automobile engines. This occurs when
the fuel-air mixture in the cylinder of an engine detonates
in localized areas rather than burning as a wave front
originating at the spark plug. This can cause a loss of
power and, in severe.cases, possible engine damage. To
improve antiknock performance, branched-chain aliphatic
hydrocarbons or aromatic compounds that resist detonation
are blended into the gasoline. In leaded gasoline, anti-
knock performance is further improved by blending small
quantities of additives containing tetraethyl- and/or
tetramethyllead into the gasoline.
Brief Overview of the Report
Section 3 presents component analyses for each major
gasoline blending stock, together with published survey
results of gasolines. This section also presents data on
gasoline vapor composition for hydrocarbons only, on air-
hydrocarbon equilibrium composition as a function of season
of the year, gasoline additives, and on gasoline vapor.
The toxicity of gasoline and gasoline vapor is distin-
guished by the toxic effects of its hydrocarbon components.
Section 4 contains the results of a review of toxicity
literature regarding inhalation exposures to paraffins,
olefins, naphthenes, aromatics, and gasoline additives. It
also contains an assessment of health effects associated
with gasoline vapor inhalation and a review of epidemio-
logical studies related to gasoline vapor exposure.
Section 5 evaluates the relative effectiveness of
possible techniques for controlling toxic components com-
monly present in gasoline vapor.
2-2
-------
2.1 REFINERY PROCESS DESCRIPTION
Figure 2-1 is a schematic of a processing plan for a
typical complete gasoline refinery. This plan shows the
process flow of .the main gasoline blending streams. Process
unit configuration varies among refineries. Not all re-
fineries contain all of these units. In an integrated
refinery gasoline blending stocks are formed from most crude
unit or atmospheric distillation tower streams. The purpose
of the crude unit is simply to provide physical separation
of the crude oil (by fractional distillation) into compon-
ents with a boiling range that permits their being processed
into specific products in subsequent equipment. Boiling
ranges of these components (or fractions) vary among re-
fineries, but Figure 2-1 shows the fractions into which a
typical crude unit will resolve the crude. The naphtha
splitter, gas/oil splitter and vacuum distillation tower are
considered part of the crude unit because they further
separate the fractions by boiling range.
The major gasoline blending streams in a modern re-
finery are light straight-run gasoline, reformate, catalyt-
ically (cat) cracked gasoline, hydrocracked gasoline, alky-
late, and thermal gasoline (coker or visbreaker naphtha*).
Some of these streams are further processed to reduce the
sulfur level or upgrade the octane level (e.g. by catalytic
reforming or by isomerization). These streams are described
briefly below.
Light Straight-run Gasoline. This fraction of the
crude generally contains all hydrocarbons lighter than C_
and consists primarily of the native C^ and C, families.
This light fraction from the crude unit is stabilized to
*
Note naphtha refers to gasoline boiling range streams rich
in saturated ring compounds or naphthenes.
2-3
-------
c*4
1 LIGHT f«
ro
C« To i«>o**
"*1 CS lfcO-2OO*P
a
cs
1C* FO« ALKVLATlOJ
MC*
PUKCMA«VfcO MA.TURM. v<«
Figure 2-1. Typical integrated refinery
processing plan. Based on Texas Gulf coast data (1)
NOTE: HDU is hydrodesulfurization unit.
-------
remove the C. and lighter hydrocarbons, which are routed to
a central gas concentration unit for further resolution.
The stabilized C5/C, blend usually contains odorous mercap-
tans, and it must be treated for odor improvement before
delivery to the refinery gasoline pool.
Reformate. The chemical composition of the naphtha
fraction governs its octane number. Although octane number
varies with the crude source, it will average between 40 and
50. The octane number of the naphtha fraction must be
raised (by changing its chemical composition) before it is
suitable for blending into finished gasoline pools. This is
accomplished by catalytic reforming.
The chemical reactions involved in reforming the hydro-
carbon molecules in naphtha include dehydrogenation of
naphthene to aromatics, dehydrocyclization of paraffins to
form aromatics, isomerization of paraffins to more highly
branched isomers, and hydrocracking of heavy paraffins in
naphthas to paraffins of lower molecular weight (2).
Aromatics have the highest octane ratings of the
hydrocarbons residing in naphthas and in the reformed pro-
duct. N-paraffins have very low ratings. Naphthenes are
classed as intermediate in octane ratings, and isoparaffins
as high.
Reforming provides flexibility in meeting the motor
fuel and aromatics production needs. The operating condi-
tions can be varied such that increased severity of catalyst
operating conditions reduces yield while increasing reform-
ate octane number. This is done primarily by simultaneously
increasing aromatics yield and decreasing the concentration
of heavy paraffins. In many refineries aromatics such as
benzene, toluene, and C0 aromatics are separated from
o
2-5
-------
reformats and used as petrochemical feedstock. The non-
aromatic hydrocarbon stream from this separation, termed BTX
raffinate, is used for gasoline blending.
Cat-cracked Gasoline. The primary function of cataly-
tic, cracking is to convert into gasoline those fractions
having boiling ranges higher than that of gasoline. An
important secondary function is to create light olefins,
such as propylene and bytylenes, to be used as feedstocks
for motor-fuel alkylation and petrochemical production.
Isobutane, a necessary reactant for the alkylation process,
also is an important product of catalytic cracking, as are
heavier fuels. The gasoline produced contains substantial
proportions of hydrocarbon components with high octane
numbers. These include aromatics, branched paraffins, and
olefins.
The principal feedstock is the gas/oil separated from
the crude by vacuum distillation, but it is often supple-
mented with portions of other distillate streams.
Hydrocracked Gasoline. Hydrocracking normally comple-
ments catalytic cracking by converting any heavy distillates,
Sometimes hydrocracking is used to convert cycle oils when
complete conversion is impractical in catalytic cracking
units. The main products of hydrocracking are gasoline or
jet fuels and other light distillates. Hydrocracked pro-
ducts differ from cat-cracked products in that they are not
olefinic and are lower in octane number and aromatics con-
tent. Because it is high in naphthenes, the C_+ naphtha
from this process normally is used as a feed to reforming.
Alkylate. In motor-fuel refineries, alkylation units
produce high-quality paraffinic gasoline by chemical combus-
tion of isobutane with propylene and/or butylenes. A small
amount of pentenes are also alkylated. Alkylate, which
2-6
-------
consists primarily of C_ to Cq paraffinic isomers, is a
high-quality blending stock for refinery gasoline pools. It
is especially suitable for premium-grade gasolines because
of its excellent octane number response to the addition of
lead alkyl's.
Thermal Gasoline. A small amount of thermal gasoline
is made as a by-product from coking or visbreaking units.
Because its octane number is relatively low, it is sent to a
gasoline pool or to catalytic reforming after it has been
treated for sulfur removal.
Table 2-1 presents the processing configurations of
major refinery units. Relative differences among areas of
the country are partially due to variations in crude oil and
market demands. These variations are also reflected in
different gasoline composition. Regional differences
between refinery flow schemes is illustrated in Table 2-1.
West Coast refineries can be seen to be most atypical. This
is in part due to highly aromatic crude oils used which are
not good feedstocks for cat crackers, resulting in more use
of hydrocrackers while residues are sent to coking units.
2-7
-------
Table 2-1. SUMMARY OF MAJOR REFINERY PROCESSING UNITS (1)
(Percentage of Crude Capacity)
Refinery location
to
i
00
Processing unit
Catalytic reforming
Catalytic cracking
Hydrocracking
Alkylation
Delayed coking
Texas
Gulf
23
33
6
6
6
Louisiana
Gulf
18
41
4
11
9
Large Small East
midwest midcontinent coast
21
35
0
9
10
27
39
0
9
10
23
34
5
4
0
West
coast
24
39
16
4
24
-------
REFERENCES FOR SECTION 2
1. Arthur D. Little, Inc. The Impact of Lead Additive
Regulations on the Petroleum Refining Industry: Vol.
II. EPA-450/3-76-016-b. May 1976.
2. Sterba, M.J. Reforming in Chemical Process Technology
Encyclopedia. D.M. Considine, ed. McGraw-Hill, New
York. 1974.
2-9
-------
;. .3.0 GASOLINE COMPOSITION
(
3.1 COMPONENT ANALYSIS OF GASOLINE
Chemical composition of a gasoline depends on grade
specifications and the amount and composition of each blend
stock. Table 3-1 presents typical gasoline specifications
for refineries from various areas in the United States. The
only significant difference in product specifications
between grades and refineries is the research octane number
(RON) and the motor octane number (MON).*
Gasoline is routinely measured by gravity, lead level,
octane number, distillation curve, and vapor pressure rather
than by component analysis. Figure 3-1 shows a distillation
curve with the boiling points of selected components, and
Table 3-2 presents a summary of commonly measured gasoline
parameters. These data summarize analyses of summer and
winter gasolines from service stations throughout the
country. Within a season, grades of gasoline will exhibit
*
The octane rating of a motor fuel is defined in terms of
its knocking characteristics relative to those of blends
of isooctane (2,2,4-trimethylpentane) and n-heptane.
Arbitrarily, an octane number of zero has been assigned to
n-heptane, and a rating of 100 to isooctane. The octane
number of an unknown fuel is numerically equal to the volume
percent of isooctane in a blend with n-heptane that has the
same knocking tendency as the unknown fuel when both the
.unknown and the reference blend are run in a standard
single-cylinder engine operated at specified conditions.
Motor Method octane numbers are measured at more severe
engine conditions and are numerically lower than those
determined by the milder Research Method. The difference
between the two numbers is terms "sensitivity" (1).
3-1
-------
Table 3rl. TYPICAL GASOLINE SPECIFICATIONS
Maximum Reid vapor pressure
% evaporated at 150°F Min.
Max.
% evaporated at 210°F Min.
Max.
Minimum leaded RON ,
MON
Gasoline specifications (2)
Premium Regular Unleaded
10.5
20
28-30
42
54
99.3-100.5
90.2-94.0
10.5
20
30
42
54
92.2-94.1
84.5-86.8
10.5
20
30
42
54
92
84
3-2
-------
400
300
|
I
200
100
>
/r
A
A*- Cydop
f>^ n-ptntone
s\
sf
1-mi
rhyl 1,2
o-xyltr
ethylber
(umene
t -fci^
Ithylbeniene >< 1
^f Toluene
l^t 1 1
2, 2, 4-trimethylpenlon
* 2, 3-dirnethylpentane
/£+ Beniene
- n-heiane
3-dimett
entane
ylbulom
IWlf^
^J
e (lio-or
/
one)
/
0 It 20 30 40 SO M 70 M W 100
Fraction evaporated, /.
k~e»: CM 4 O J.ir..l
Figure 3-1. Distillation curve for typical gasoline (3)
3-3
-------
Table 3-2. SUMMARY OF VALUES, MOTOR GASOLINE SURVEY
Test
Grovity, "API-
Corrosion, No.
Sulfur content, wt %
Gum, mg/100 ml
Mongonese, AA, g/gol
Leod, g/gol
Octone number, Rejeorch
Octone number, Motoi
Antiknock index |(R * M)/2I
Reid vooor pressure, Ib
Vapor-liquid ratio of 20, *F
Distillation
Temp, °F
IBP
5°r evaporated
10% Do.
20% Do.
30% Do.
50% Do.
70% Do.
90% Do.
95% Do.
End point
Residue, vol %
loss, vol %
ASTM
method
D?87
DI30
DI266
D381
D526
D2699
D2700
D323
D439
D86
Grades of motor gosolinel
Unleodtd
Average
61.7
1
0.028
1
0.03
-
92.6
84.1
88.4
12.4
122
83
95
107
131
158
212
257
327
362
404
0.9
2.2
Rtgulor
Average
62.6
1
0.040
1
-
1.71
93.2
86. 1
89.7
12.4
120
83
95
107
128
151
202
259
335
369
409
0.9
2. 1
Premium
Average
63.2
1
0.027
1
-
2.28
98.8
91.4
95.1
12.2
123
83
95
108
131
158
210
254
326
361
404
0.9
2.2
Test
Gravity, "API
Corrosion, No.
Sulfur content, wt %
Gum, mg/100 ml
Phosphorus, g/gol .
Lead, a/gal
Octane number, Research
Octane number. Motor
Antiknock index |(R+M)/2]
Reid vaoor pressure, Ib
Vapor-liquid ratio of 20, °F
Distillation
. Temp, *F
IBP
5% evaporated
' 10% Do.
20% Do.
'30% Do.
50% Do.
70% Do.
90% Do.
95% Do.
End point
ftnidue, vol %
loss, vol %
ASTM
method
D287
DI30
D1266
D38I
D323I
D576
D2699
D2700
D323
D439
D86
Grades of motor gasolines
Unleaded
Average
59.7
1
0.028
1
0.001
-
92.4
83.9
88.2
9.7
137
89
107
121
146
173
220
264
332
367
411
0.8
1.7
Regular
Average
60.2
1
0.043
1
0.001
2.04
93.3
86.0
89.6
9.6
135
90
107
120
141
163
211
266
342
377
416
0.9
1.4
Premium
Average
61.4
1
0.028
1
0.001
2.51
98.9
91.4
95.2
9.8
136
89
107
121
145
171
217
259
330
366
410
0.9
1.7
a) Winter 1S76-77
b) Summer 1976 (5)
3-4
-------
the following differences: lead level (with premium being
the highest); octane number; and the distillation data (90
percent, 95 percent, and end point, with the regular gaso-
line often showing elevated levels). It is apparent that
regular gasoline typically contains more high-boiling-point
components. A comparison of data between seasons reveals
that summer samples display higher density, lower vapor
pressure, and higher boiling points for the distillation
curve than do winter samples. This can be attributed to
winter gasolines having higher butane and pentane levels to
raise vapor pressure.
Table 3-3 presents survey data on regular and premium
gasoline for winter 1976-77, according to districts in the
United States (4). It is apparent that sulfur level, lead,
octane numbers, and vapor pressure vary among areas of the
country. Reid vapor pressure (RVP) is generally higher in
northern regions of the country because of the colder cli-
mate.
Chemical composition of a gasoline grade depends not
only on the crude oil being processed, but also on the
refinery process configuration and product slate. Table
3-4 presents projected gasoline blend data for the Texas
Gulf region. Scenarios A, B, and C represent three different
lead regulations (defined in Table 3-5). This A.D. Little
study (2), based on 1973 refining data, shows that lead
regulations have resulted in unleaded gasoline capturing a
progressively larger proportion of gasoline sales (see Table
3-5). This shift in gasoline grade distribution has caused
a restructuring of the blend data shown in Table 3-4.
Referring'back to Table 2-1, it should be noted that blend-
ing patterns vary considerably among refinery groups in
different parts of the country. These varying blending
3-5
-------
Table 3-3. MOTOR GASOLINE SURVEY, WINTER 1976-77 AVERAGE DATA
FOR BRANDS IN EACH DISTRICT (4)
DISTRICT NO.
AK9 NAME
NORTHEAST
HID-AHANTIC COAST
SCUTKEAST
APPALACHIAN
MICHIGAN
NORTH ILLINOIS
CENTRAL MISSISSIPPI
LOkER MISSISSIPPI
NORTH PLAINS
lU CENTRAL PLAINS
11 Sfi,TM PLAINS
12 SOUTH TEIAS
13 SOUTH MOUNTAIN STATES
1* NORTH MOUNTAIN STATES
IS PACIFIC NORTHWEST
14 NORTH CALIFORNIA
IT SOUTH CALIFORNIA
NO. OF
(RANDS
11
IS
17
1*
12
12
20
IS
10
11
22
11
11
13
6
10
10
SAM-
PLES
13
132
73
45
ai
32
46
63
16
42
59
47
11!
63
17
33
35
AVERAGE
OR..
ASTN
0267
API
62.*
62.3
62.3
62.2
62.5
62.3
62.2
63. 5
63.6
63.2
63.4
62. 6
63.1
62.9
62.3
62.0
60.1
62.6
SULF.
ASTM
01266
NT *
0.055
.030
.035
.027
.049
-
.034
.036
.044
.033
.040
.044
.035
.054
.020
.036
.058
.040
GUM.
ASTM
0381
MG
LEAD.
ASTM
0526
G/GAL
2.01
1.74
2.01
.73
.57
.73
.77
.94
.73
.92
.as
.75
.63
.32
.41
.62
.35
.71
OCTANE NUN!
RES.
ASTM
02699
»3.7
93.6
93.7
93.6
93.5
93.7
93.5
93.3
92.5
92.7
9J.O
93.7
91.0
92.6
92.6
94.0
93.0
43.2
MOT,
ASTM
02700
66.7
86.7
86.6
«6.1
66.0
86.2
86.3
86.6
as.3
66.0
66.?
86.7
85.2
85.1
86.0
86.2
85.5
66.1
ER
R«N
2
90.2
90.2
90.3
89.9
89.8
90.6
90.0
90.0
88.9
89.4
89.8
90.2
68.5
68.9
89.4
90.1
69.3
89.7
RVP.
ASTM
0323
LB
13.4
12.6
11.4
13.1
13.6
13.1
12.6
12.2
13.5
11.6
12.1
11 .9
11.6
12.5
12.8
11 .8
11.1
12.4
20V/1
ASTM
0439
F
115
119
124
117
116
117
120
120
117
124
121
121
125
120
119
123
127
120
DISTILLATION. ISTM 086
TEMPERATURE, F (CORRFCTED TO 763 X"
1 PERCENT EVAPORATED
IBP | 5 13 20 30 50 70 90 95
82 92 101 120 142 198 269 3*2 377
62 92 104 124 146 203 263 340 373
66 99 110 130 151 202 263 339 370
60 93 103 124 14S 199 255 331 369
80 90 103 124 150 235 264 344 380
61 89 102 123 147 232 259 337 376
83 95 106 127 152 204 260 337 372
83 96 105 125 146 197 256 334 366
64 95 109 131 153 231 254 ?J2 >64
85 97 109 129 154 203 257 331 166
62 94 136 127 149 199 254 331 367
63 95 106 126 148 199 255 333 366
66 101 113 134 156 204 257 332 369
65 97 109 130 153 201 254 Ji3 365
82 92 105 12* <53 203 256 335 365
85 99 112 Ii3 155 232 253 324 369
66 102 114 135 157 207 266 338 16»
63 95 107 121 151 202 259 335 369
MGI
fP
411
415
408
409
422
413
413
409
404
406
408
404
410
409
400
404
410
409
RES LOSS
t *
0.6 2.0
.9 2.J
.6 1.5
.9 2.)
1.0 2.*
1 .0 2.1
1 .0 .7
.6 .*
.9 .4
.9 .6
.8 .1
1 .0 .4
.9 .6
.9 .5
1 .1 .2
1 .0 .1
1 .1 .6
.9 2.1
912
PREMIUM GASOLINE
OUTPUT NO.
Alib NAME
NORTHEAST
MID-ATLANTIC COAST
SOUTHEAST
APPALACHIAN
MICHIGAN
NORTH ILLINOIS
CENTRAL MISSISSIPPI
LOMER MISSISSIPPI
NORTH PLAINS
13 CENTRAL PLAINS
II SOUTH HAtNS
12 SOUTH TEIAS
U SOUTH MOUNTAIN STATES
14 NORTH MOUNTAIN STATES
15 PACIFIC NCRTHkEST
l» NORTH CALIFORNIA
17 SOUTH CALIFORNIA
NO. OF
BRANDS
9
16
17
12
13
12
19
12
7
9
16
11
16
14
7
12
12
SAN-
PIES
10
110
63
45
44
27
37
52
10
34
46
44
113
59
19
37
40
AVERAGE.
CR..
ASTM
D287
API
62.8
61.1
61.4
63.4
61.7
63.4
63.9
63.2
66.2
64.9
65.0
62.4
65.1
66.7
62.5
60.1
56.9
63.2
SULF.
ASTN
01266
NT *
0.030
.019
.025
.022
.036
-
.021
.026
.015
.019
.034
.021
.025
.045
.012
.015
.037
.027
GUM.
ASTN
0361
MG
1
1
1
1
1
0
1
1
-
1
1
2
0
0
0
1
1
1
LEAD.
ASTM
0526
G/GAL
2.66
2.36
2.52
1.96
2.12
2.27
2.17
.49
.34
.36
.31
.48
.02
.86
.11
.36
.32
.28
OCTANE NUMBER .
RES.
ASTN
02699
»9.1
99.3
99.0
96.6
96.6
49.1
98.9
99.0
98.6
98.5
98.8
99.1
97.7
98.7
99.6
98.7
98.6
98.6
MOT.
ASTN
D2700
91.1
91.4
91.6
91 .8
91.6
91.5
92.3
91.8
91.3
91.7
92.4
91.7
91.1
90.7
91.0
90.9
90.7
91.4
R»M
...
2
95.1
95.3
95.3
95.3
95.1
95.3
95.6
95.4
95.1
95.1
95.6
95.4
94.4
94.7
95.3
94.6
94.6
95.1
RVP.
ASTM
0323
LB
13.1
12.3
11.3
12.9
13.5
13.2
12.8
12.2
11.4
11.4
11.7
11.7
11.6
11.9
12.1
12.0
11 .2
12.2
20V/L
ASTM
D439
F
116
121
124
119
116
118
120
121
126
125
125
124
126
124
121
123
126
123
DISTILLATION, ASTM 086
TEMPERATURE. F (CORRECTIO TO 760 NK
J PERCENT EVAPORATED
5 10 20 30 50 70 90 95
83 93 105 126 150 210 260 331 162
61 93 105 127 153 211 260 330 363
66 99 110 132 157 212 262 329 359
60 92 103 125 152 206 254 321 359
81 90 104 129 160 215 256 333 372
61 16 102 126 156 208 250 327 364
82 94 104 126 160 210 246 319 157
62 96 106 127 152 206 253 325 356
67 102 116 141 170 209 244 124 367
65 97 109 111 157 207 245 12) 163
81 95 108 114 162 211 249 125 364
65 96 106 129 155 210 260 329 364
65 99 112 115 140 212 255 327 367
85 99 112 116 161 207 242 320 353
80 69 102 128 157 204 255 322 349
64 98 111 114 156 206 256 124 358
66 101 114 119 166 215 263 129 362
63 95 108 131 156 210 254 326 361
SAMPLES 790
HGI
EP
403
402
404
407
416
407
400
349
408
404
409
404
410
400
165
407
407
404
RES LOSS
> *
0 9 1.4
4 2.5
8 1.5
8 2.5
9 2.6
1 0 1.1
7 2.1
6 1.7
4 2.0
1 0 1.6
8 2.1
4 1.4
1 0 2.0
4 1.1
1 0 3.5
1 0 2.1
1 0 2.0
.9 2.2
-------
Table 3-4. GASOLINE BLENDING SUMMARY (6)
CO
Cluster: Texas Gulf
Scenarios
Lead-free pool
Research octane clear
Motor octane clear
Volume MB/CD
Sulfur PPM
Composition LV%
BTX raffinate
Butanes
100 RON reformate
Gat cracker gasoline (untreated feed)
Alkylate
Light hydrocrackate
Isomerized light naphtha
Coker gasoline
Natural gasoline
Straight run
Total
Total gasoline pool
Research octane clear
Motor octane clear
Volume MB/CD
Lead CC/USG
Sulfur PPM
Year
1977
A
92.7
84.0
11.48
408
5.2
16.9
36.6
17.9
20.5
-
-
2.9
100.0
87.9
79.8
164.01
1.98
419
B
92.6
84.0
50.62
369
6.2
22.2
31.8
18.3
13.8
-
-
7.0
0.7
100.0
88.7
80.4
163.30
1.51
412
C
93.2
84.0
49.99
44
-
6.3
60.4
-
-
5.3
5.0
1.1
21.9
100.0
91.2
82.1
161.27
0.94
401
1980
A
92.7
84.0
3.23
285
6.2
16.8
35.1
20.4
11.1
-
-
10.4
100.0
87.8
79.7
161.36
2.10
397
B
93.1
84.0
94.08
261
-
7.5
37.0
22.8
13.1
6.5
1.8
-
8.4
2.9
100.0
90.3
81.4
159.45
0.96
404
C
93.9
84.0
93.33
216
-
6.7
45.1
22.8
3.6
6.0
6.4
-
9.4
-
100.0
92.0
82.8
158.20
0.47
387
1985
A
94! 7
84.0
3.15
197
5.8
59.8
13.4
-
10.3
, 10.7
100.0
88.3
80.1
157.25
2.11
482
B/C
93.24
84.0
152.33
309
2.1
7.2
29.0
30.6
12.5
3.4
9.5
1.1
4.6
-
100.0
93.2
84.0
152.33
309
-------
Table 3-4 (continued). GASOLINE -BLENDING SUMMARY (6)
Cluster: Texas Gulf
i
Scenarios
Premium pool
Research octane clear
Motor octane clear
Volume MB/CD
Lead CC/USG
Sulfur PPM
Composition LV%
BTX raffinates
Butanes
90 RON reformate
95 RON reformate
100 RON reformate
Cat cracker gasoline
(untreated feed)
Alkylate
Light hydrocrackate
Coker gasoline
Straight run
Total
Regular pool
Research octane clear
Motor octane clear
Volume MB/CD
Lead CC/USG
Sulfur PPM
Composition LV%
BTX raffinate
Butanes
90 RON reformate
100 RON reformate
Cat cracker gasoline
. (untreated feed)
Alkylate
Isomerized light naphtha
Coker gasoline
Natural gasoline
Straight run
Total
Year
1977
A
91.9
83.5
41.00
2.03
619
-
7.0
-
-
10:1
52.0
27.9
-
-
3.0
100.0
85.9
78.0
111.53
2.16
347
9.1
7.3
35.1
22.9
1.3
-
3.0
9.8
11.5
100.0
B
91.1
83.0
21.23
2.16
602
-
8.9
-
-
-
50.3
31.2
-
-
9.6
100.0
86.0
77.8
91.45
2.20
391
10.4
6.6
35.5
24.3
0.8
-
2.0
7.2
13.2
100.0
C
91.5
83.5
20.96
2.02
293
14.0
8.8
37.3
25.7
13.5
-
0.7
100.0
90.1
80.8
90.32
1.20
624
3.1
' 6.6
3.5
9.1
47.9
14.7
1.4
-
13.7
100.0
1980
A
92.2
83.8
50.02
1.99
625
-
6.8
-
-
-
52.4
26.8
13.9
-
0.1
100.0
85.6
77.7
108.11
2.22
295
9.1
7.1
39.5
18.2
0.6
3.6
-
9.0
12.9
100.0
n
91.1
82.9
4.78
2.1G
596
-
6.5
-
-
49.6
31.1
-
-
. 12.8
100.0
85.9
77.3
60.59
2.35
612
14.0
5.6
16.9
40.4
4.9
-
2.9
-
15.3
100.0
C
90.7
82.5
4.75
2.29
770
-
8.1
-
-
-
42.8
35.3
-
5.8
80
100.0
89.1
81.0
60.12
1.06
633
7.7
6.7
2.3
44.5
22.4
-
2.5
-
13.9
100.0
1985
A
92.1
83.6
59.76
2.03
640
-
7.6
2.1
9.2
0.5
41.8
24.6
12.8
-
1.4
100.0
85.7
77.7
94.35
2.23
391
9.9
6.0
39.8
_
19.9
-
-
1.8
8.6
14.0
100.0
3-8
-------
Table 3-5. GASOLINE GRADE REQUIREMENTS BY PERCENT (6)
Grade Distribution %
District*
A. No load reflations
Premium (100 RON)
Regular (94 RON)
Unleadtd (92 RON)
B. Unleaded with no lead phasedown
Percent of pool
Premium
Regular
Unleaded
C. Unleaded with lead phasedown"
Promulgated lead
phasedown pool
average, grams/gal.
Allowable grams of
lead per gallon of leaded gasoline
1977
I II III IV V
27 16 25 13 38
65 76 68 80 52
8 8 7 7 10
15 5 13 3 22
54 63 56 66 42
31 32 31 31 36
1.0
1.74
1980
I II III IV V
33 22 31 19 44
64 75 67 79 52
33 2 2 4
41315
37 39 38 40 31
59 60 59 59 64
0.5
1.66
1985
1 II III IV V
40 29 38 26 50
58 69 60 72 48
22222
00000
00000
100 100 100 100 100
b
'
b
U.S. average
1977 1980 1985
24 30 37
68 68 61
832
12 3 0
56 37 0
32 60 100
1.0 0.5 b
1.74 1.66 b
OJ
I
vo
'same distribution pattern used as in unleaded (Item B.)
*District designation I
II
III
IV
V
East Coast
Midwest
Texas-Louisiana
Rocky Mountain
West Coast
-------
patterns result in significant variation in gasoline com-
ponent analyses.
3.1.1 Gasoline Blending Stocks
This subsection presents an analysis of the compositions
of major gasoline blending components, which, together with
\
blending component data of the type shown in Table 3-4,
will provide a clearer picture of major variables affecting
gasoline composition. Some composition data are presented
as a breakdown by fraction of paraffins, olefins, naphthenes
and aromatics (PONA), respectively. Table 3-6 shows the
overall properties of major gasoline blending components.
Reformate. The catalytic reforming process increases
the octane number of naphtha feed streams by the following
reactions:
Isomerization of paraffins
Hydrocracking
Dehydrogenation (isomerization of naphthenes)
Dehydrocyclization of paraffins (7)
Thus, characteristically, a reformate is very high in
aromatics and branched-chain paraffins, which have good
octane ratings. Table 3-7 presents reported reformer yield
and product quality data, and Table 3-8 (below) shows a
breakdown of aromatics in reformate.
Table 3-8. ANALYSIS OF REFORMATE AROMATICS
Octane blending
Volume % of reformate values (3)
37 8
Source A B C 0 gm Pb 3 gm Pb
Benzene 5 3.5 2.2 108 112
Toluene 24 13.9 17.3 112 115
Ethylbenzene 4 3.6 7 113 116
P-xylene 4 4.5 114 115
M-xylene 9 10.1 28.6 114 116
0-xylene 5 5.2 100 96
Cg and cioaromatics 4 31.4 18.8 103 107
3-10
-------
Table 3-6. MAJOR REFINERY GASOLINE BLENDING
COMPONENTS (3)
Gasoline-
blending
component
Light straight
run naphtha-
LSR
Cat naphtha
Alkylate
Isomerate
Reformate
Hydrocrackate
Extract
*
Raffinate
Source
Crude-oil
distilla-
tion
Catalytic
cracking
Alkylation
Isomerization
Catalytic
reforming
.
Hydrocracking
Solvent
extraction of
reformats
Solvent
extraction of
reformate
Major
hydrocarbon
constituent
CjiC,
paraffins &
cyclo-paraffins
C5 to C,u
paraffins,
olefins, some
aromatics
Primarily C,-
C» branched
paraffins
Ca&C,
branched
paraffins
C, to C,
aromatics,
paraffins
Cs to C,
paraffins
C, to C,
aromatics
C, to C,
paraffins
Research
unleaded
60-72
91
94
82-92
90-95
85
111
65
Octane
rating.
3 gm Pb/gal
82-89
98
105
92-101
97-101
97
114
85
3-11
-------
Table 3-7. REFORMING FEED AND PRODUCT DATA (8)
a) Houdriforming
HOUDRIFOKMING IN MOTOR OASOUNE
b) Rheniforming II
c) Ultraforming
Drbutaniied Reiormale, Vol. 7
rMI S
07 7
81 S
7(1.2
Rrfnrm.itf Intprrtirm
Cr.viiv. 'API
AS'IM Dist., °F
IBP
in
30 .
SO ...
F.P
Rnrarch (> N Clear
Rr7.8
1.9 2.6
15.7 18.8
28.3 2B.9
19.0 15.9
1.2 1.6
Mid- Hc»r
Kuwait Cvnlincat Naphtha
Cktttt Niphlhi
ASTM Dist., T
Initial
I"",,'.
»o%
kp" . . .
Paraffins, vol. T,
Arornslics »ol. ^
ttttuctt
C.4 Ullnforniatr
Rt«-.rrh ON. rlc.r 07
Yirld. vol. >; 7C.4
UVI'. pni I.H
Aromatirv. vr>' '" *.(
Butane TO! <70 . . . (.0
Ci-Ct. wt. % 14.0
Itydroiten. arf/bhl I.I (HI
IWI 172 202
I!I2 220 232
222 2S7 2(6
2M 3II.S 340
2ft5 368 409
74 52 31
8.5 13 41
IKI lOtl 103 100 103
74.11 R2.0 77.B Mtl RS.a
t.l 4.1 4.4 3.5 3.8
IMJ 72 7» 75 81
7.S J.S 4.6 2.8 4.0
11.7 B.S 12.3 >.« K.2
l.l^n (.170 1.370 Km no
inn
91. »
3.4
72
1.7
1.4
MO
xarch O.K.
Clear
90
100
102.5
Reformate
43.8
110
180
222
252
342
415
100.0
104.2
20.5
1.5
M
Isocneked
Naphtha
200-370
32.6
55.5
11.9
< 0.2
< 0.5
200
1380
185
85.4
100
27.4
2.2
70.4
1.3
14.0
26.1
19.6
9.4
Hrd'rZ
CHckaK
224
240
273
111)
380
25
3>
103 lOb
M.4 ».'
3.7 4...
77 (M
l.S 4.1
M la-
Mi) MO
3-12
-------
Yield distribution depends on reformer feed characteristics,
differences among individual processes, and the operating
severity of the process. Octane values of the aromatics, as
shown above, are very high but their response to lead
addition is relatively poor, making them ideally suited for
raising the octane rating of an unleaded gasoline. The
effects of reformer operating severity (altering the operat-
ing conditions to produce a desired octane reformate) are as
follows (3):
Reformer severities
RON, clear
89 to 91 93 to 95 99 to 101
C5+ reformate, vol % of feed 85 80 72
Aromatics, vol % of reformate 48 55 66
Paraffins, vol % of reformate 52 45 34
Fuel gas and light ends, vol % 15 20 28
of feed
Raising the octane number of the reformate reduces the
overall reformate yield, whereas it increases the aromatics
and decreases the paraffin levels in the reformate.
Cat Naphtha. Cat cracking, which involves selective
decomposition of heavy distillates, produces gasolines with
high levels of aromatics, branched-chain paraffins, and
olefins. As shown in Table 3-9, cat-cracked naphtha composi-
tion is strongly dependent on the cat-cracker feed charac-
teristics. A feed high in aromatics characteristically
results in low gasoline yields and a product rich in aro-
matics. A paraffinic feed results in high gasoline yields
and a product with higher saturate and olefin concentration
(9). No recent component analyses of cat naphtha were
available, but Table 3-10 presents a 1949 analysis of cat
naphtha. Although subsequent improvements in the catylysts
3-13
-------
Table 3-9. CAT CRACKING YIELD CHARACTERISTICS
a) Gulf FCC >(8)
Chuff lUck
Inftpcclioft*
Gravity.
Sulfur, wt. %
Rims, orbon.
wt. 7r. ..
ASTM distill.. *V
10%
507,
70%
007,,
Vol. % rnidf
Yield*
Conversion.
vol. %...
Gasoline:
Cs-430'F TB1'
Light T.-275' f
Hrnvy
275-430'K
TnUir,...
Hntrno*..
i('4/nr4 ratio
Total Ci.
Prnpcnr..
l.ilhl CM oil
Decanted oil.
-------
Table 3-10. CAT NAPHTHA COMPONENT ANALYSIS (10)
Type of
Hydrocarbons
Normal paraffins
tsoparallms
Cycloparafnna
Aroma tici
Olenns
Total
.-
ANALYSIS BY TYPE or HYDROCARBON*)
Amount, Vn|. %
4.4-1.01., . . . 4 .2-1.51,. T^.
42.7*o.4r7-'-V4 S0.6-5.6r4-7*5
10.8-5.4 21.0-5
31.0-0.3 39.0-0
4.2-0.4 4.4*0
100.0 100.0
(IPS
5
5
4
5
ANALYSIS ur COMPONENTS roit MATEIIIAL XOIUIAI.I.T llou.i.vc; AH cm: JI-I'ENTANE
Boiling
Point at
1 Aim.. C.
49.3
49.7
68.0
60.3
63.3
49-69
68.7
69-81
71.8
80.1
79.2
80.5
80.7
87. S
89.8
00.1
00.8
01.9
92. 0
81-101
08.4
100.9
101-112
103.5
105.0
100.8
109.1
109.4
107-112
110. C
112-117
112.0
115.6
117.6
117.7
118.9
119-126 .
125.7
112-146
120-135
130-137
I3A.2
135-141
138.4
139.1
137-145
137-145
144.4
141-150.8
150.8
152.4
159 2
>I50.S
>l&0.8.
>HO
101.3
102.1 '
104.7
105.2
109.1
109.3
172 8-177.1
>177.3
Coiupunoiita
Cyclnpentano
2.2-Uimclbylbutane
2,3-nimcthyllmUno
2-Mrtliylpciitan«
S-Mctliylpentano-
Olcftns
ri'Hexane
OlPfina
Mclliylcyclopentane
Benzene
2.2-Diinclliyl|>onUncl
2.4-PimethylpcntanrJ
Cyclohcxone
1.1-nimrtliylcyrlopcntane
2.3-niinctliylprntanel
2-Mctbyllinanc /
{ran«-l,3-l)iinrthylcycln]>ontane
frani-1.2-Dirueihylcyclopcntanc*
3-Methylbcxaue
Olefins
n-llrptanc
Metliylcyclolicxane
Olefi.u
Etliyli-yclopoDlunc
1,1,3-Triinelliylryrlopeniane
2.2-DiniPthylhcxane
2,5-Diine(hyllicxane\
2.4-l)iiucibyllicxano/
Triraclbylcyclopeolanea
Toluene
Trimelbyleyclnprntanea
3.3-DinielhylhcianeU
2.3-Dimclhyllicxanc/
2-Metliylhrplane')
4-Mribyllieptane |
3-Mrthylheplanc ]
Dimethylcyclobuanea*
n-Oclane
Olefins
Naphlhenra
Uiiiicthylheptanes
Llthylbcnzcne
Napblhcnoa'
p-Xylcne*
m>Xylcne
Dimrlliylheptanrsl
Mi-tliylociancs J
o-Xylcnc
Naphlhencs
n-Priipylbrnzciio /
1'arallins
Olvliiu
l-Molhy|.3-clhylbcnicnel
]-Mctliyl-4*elliylhcnsonoJ
l-Mclhyl-2-rlnylliuntrnp/
1 .2. l-Trnnrl hrlrvrimM/
l.2.3-Trlinrfhrll"->ir-ii' and CM Aromalita
Cia and liigh'-r Ammatin'
lianeil on all
coinpolionU
0.20-0.101 n .0^0 .
0.20*0. IS/ (MO-0->
1.95-0.45)
6.0-0.5 [13.5-0.3
4.05-0.30)
3.V-0.3
1.8-0.2
0.0-0.3
0.4-0.2
0.20-0.1
3.0*0.0
2.0-0.4
1.7-0.4
2.5-0.6
1.3-0.41
2.6*0.4;
1.3*0.4
1.4 -0.3
0.6-0.3
7.0*0.3
5
10.0-0.3
0.4-0.2
3.9-0.4
0.0-0.4
0.6*0.3 1
0.4*0.2 1.1*0.3
0.10*0.00]
0.6*0.3
0.8-0.5
8.6-0.4
0.4-0.2
0.8*0.5
2.8*1.1)
2.9*1.1
0.8-0.4]
1.0*0.4)
0.0-0.4
1.6*0.4
1.1*0.6
3.4*0.2
8.8-0.3
1.7-0.6
4".0-0.3
1.0*0.5
0.7*0.4
0.4*0.2
1.8*1.0
2.8-1.0
1.4-0.4
0.7*0.4
6.6-0.8
0.8*0.4
23.6*0.6
6.7*0.4
0.6*0.2
3.6-0.3
2.6*0.3
3.6-U 3
0.7*0.3
1.0-0.3
Total
May include some ci's-l.3-dinielliylryclo|>enUiM.
» May include tome 2-n>elhyl-3-<>lliyl|>«nUne.
* May include some 3,4-dimftihylhcs.ane.
* May include some tatIbylelhylcyclopenUoa.
100 0
Determined Irom (reeling point iiKuuniuoaU.
/ Prr«ont only in imall ainnunt (11.2%).
a-Butylb«ni«n« (b.p. 1S3* C.) wa« uxxj a*
-------
used in cat cracking have increased gasoline yields and
octane ratings, this 1949 analysis is indicative of the
range of components present in cat naphtha.
Alkylate. :,Alkylation involves combining isobutane with
C-, to Cc olefins to form Cc to Cn paraffinic isomers. Table
J . b ' oy
3-11 shows the composition, by carbon number, of a deput-
orized alkylate made from a mixture of C, and C. olefins
with hydrofluoric acid as the catalyst. The table also
shows a breakdown of the Cg fraction of this alkylate. It
is apparent that these highly branched chain species pre-
dominate. Table 3-11 also shows pure component properties
of C. to Cg paraffins. The more highly branched paraffins
exhibit markedly higher octane ratings (as RON and MON).
Also it should be noted that the octane number improves much
more in paraffins than in aromatics with the addition of
lead alkyls. (Refer to the earlier description of reform-
ate.) These properties characterize alkylates as being a
high-quality blending stock for refinery gasoline pools, and
especially for premium-grade gasolines (1).
Hydrocracked gasoline. Hydrocracking is often used to
complement cat-cracking units, especially when crudes are
high in aromatics. Products in the gasoline boiling range,
especially the heavier naphthas, typically exhibit a very
high naphthene content as shown in Table 3-12. The heavier
naphtha is generally catalytically reformed to improve the
octane rating, and therefore exhibits properties similar to
those for hydrocracked feed (Table 3-7).
Light straight-run gasoline. This fraction generally
contains the C5-Cg families of the hydrocarbons in the
crude; C. .and lighter hydrocarbons are normally removed.
Light straight-run gasoline has the lowest unleaded octane
rating (typically just under 70) of any of the components in
3-16
-------
Table 3-11. ALKYLATE PROPERTIES
Cnm/>nnrlii
(*.' l-'riirliiin
C, l*(,mrr Vol ">(
2.2.4-'l'riincili\lpcnianr . .r>H.f>
2,3.4-Triiiiriliyl|>cnianr 19.3
2,3.3-Trimriliylprmanc 9.3
2,2,3-'l'rimeihvlpfnianc 0.8
2.4-DimrthvlhcxanF . . 3.9
2.3
0.5
0.8
2.2- and 2,5-Uimethylhcxane
3,4-Dimethylhfxanf
3,3-Dimethyllirxane |
4-Mrthylhrpianc I
2-Mclhylhrptaiu: I
3-Mrlhylheptane I
2,3-Dimethylhexane |
'Same sample as described in 3. .
c) Pure component
properties (11)
Pure component properties (11)
C»mp.
iCi
Df't .
iC«
nC,
22 DMB
23 DM11
2 MF
3 MF
nC«
2,2 DM P
24 DMP
223 'I'M 1J
3.3 DM I'
2 Mil
23 UMI'
3 Mil
2.2.4 TMP
2.S UM1I
24 DM II
223 TMT
2.3 4 'I'M H . . . .
2.3.3TMI'
23 DM11
2MCi
1 4 DMH . . .
|MC»
tl.STMH . .
»li>l.
«l.
i8. 12
5S.12
72.IS
72.1S
86.17
86.17
86.17
66.17
86.17
100.211
IOU.2U
llHl.L'll
lUU.'.'ll
IIHJL'U
100.211
1IW.SU
111. 2.'
1I4.22
114.2:'
1H.22
114.2:'
114.22
114.22
114.22
114.22
114.22
128.25
(In.,
-AIM
IIII.8
llll.li
U5.0
9Z.7
K4.9
t.U.8
83.6
8U.O
81.6
77.1
77.4
72.2
71.3
75.7
708
73.1
71.7
71.2
O'J.2
04.9
G4.1
62.2
66.0
70.0
64.1
67.1
44.7
Kcid
».»..
r>i.
7:'.2
51.0
2U.4
15.0
U.U
7.4
6.8
6.1
£.0
3.5
3.3
3.4
2.H
2.8
2.4
2.1
1.7
1.1
I.I
1.1
1.0
1.0
0.9
0.8
0.8
0.7
0.6
RON
+ 0
in;1.!
M.O
U3.U
61.8
91.8
101.3
73.4
74.5
24.8
«.8
K3.I
11-M
MI.8
424
Ul.l
52.0
ino.o
55.5
(ii.2
lirj.6
1U2.7
106.1
71.3
21.7
76.3
S6.B
VI.O
Oclinf
MON
+ «
117.0
S'J.I
WI.7
03.2
93.4
-------
Table 3-12. HYDROCRACKING YIELD DATA
a) BP Hydrocracking (8) y|e|d$:
yax dis'tillate
S«>uirr
1BH iKj.lin, ran,,-, 'f
UHMIV. 'API .'
Sp. HI. 6<)V6tl°F
Sulphur. '/f "I. . ..
Nilingrn. ppm wl
l'u..i point. °F
Products: Midillr of run
H:S
Nils
CC.
l.iiihi gasoline (CVISO'F)
Ili-iivy Kjsolmc | I8II-3(K." F)
Naphtha (3ll2-374'F)
Krrminr (374-437'F)
Ca> oil (437.G!I8'F|
Koidu.- >6«K"F
Total
Hydingen consumption (chemical) . scf/bbl. of feed
Kuwait expott grade
ciude oil
.6W-L022
22.5
....0.918
2.9
. ..800
85
. on feed
3.1
O.I
5.6
6.(I
15.3
10.6
11.0
40.6
1U.2
102.5
1,510
Product Light
Inspection ffatoline
Oraxity. AIM
Sullllr. pplll wl.
Blnllliuc IiumLciA
Pairillins. 7r wl.
Olrliins. % wl.
Napli1 hcucs. ^t wt
Aruu.diics, ty wt
Fla-l, point, *F
Clon.l pi.int. 'F
Pciui piiinl. °F
Frri-x;nj< poinl. *F
Siiinki* point, mm
Anilint' point. *F
Dir^> 1 indfx
RON Cl.-ar
RON + 2.5 ml
TEL US ml.
7«.l
1
H.3
76.4
O.I
21.6
1.9
_
74.0
90.0
Heavy
gasoline
,vv:i
4
(I..1
36.9
0.3
54.2
8.6
._
62.2
78.8
Naphtha Kerosine
48.3
5
0.6
31
0.5
56.5
!2
95
-.
-
..
43.4
C
0.8
31
0.7
51.3
17
144
< 85
26
Gas oil
41.2
6
49
33
18
225
2
-30
188
78
_
Residue
41.1
6
82
16
2
380
45
__
b) Union Oil Hydrocracking (10)
Hydrocracking of light virgin gas oils to
naphtha
Properties
Gravity, "A('I. . . .
Sult'ur. \vt. '",
Nitroupn. wppm. .
Aniline |>oiiil. °F. .
Arnniaiii'y. vol. 'it.
Bnilini: ran^e, CF
so Vl.i. ;.
PO v.ii. r;.
Fhi... rF. .
Yields on feed
r i-r.i sri/iihi. ..
Blll.nnr^. vol. ''.'t
^(140° F. vol. ;;
1403.W F. vol. '
3SOlt«>° F. xol. '
cv. vni. ;;
140 -3SO° F fraction
Aromatirs vol. '/r. ...
N'aphthrne*. vol. %.. .
Paraffins, vol. %
Feedstock
0.72
110
ISTi
25
Product
IK
1>0
1)9
10
117
1.1
44
43
3-18
-------
modern gasoline blends (13).
In some refineries, isomerization processes convert the
Cc-C6 paraffins to more highly branched structures, which
results in a markedly improved octane rating. Table 3-11(c)
illustrates this improvement by comparing normal and branched
paraffin species.
Typically, light straight-run gasoline also contains
some benzene (crude oil normally contains about 0.15 per-
cent) (3,14). Based on the average of component analyses
made by Rassim and Mair (14), on eight representative crude
oils the composition of the C5 to 180°F stream was as follows:
% of crude % of cut
Normal paraffins 1.80 40
Isoparaffins 0.94 20
Naphthenes 1.63 36
Benzene 0.15 3
4.52
These composition data indicate that the low octane rating
of this stream is due to the high concentrations of normal
paraffin and naphthene.
Thermal gasoline. The quality and amount of gasoline
from coking and visbreaking units are strongly dependent on
the crude oil being processed. Thermal cracking processes
are not as selective as the catalytic processes described
above, thus the gasoline components are molecular fragments
from the residual oil feed. Thermal gasoline, a by-product
from these processes, usually has a fairly low unleaded
octane rating because it contains significant concentrations
of normal paraffins and/or naphthenes.
Normal butane is added to gasoline to raise the volatil-
ity to vapor pressure specification levels (13) . Normal
butane level is higher in the winter months because gasoline
3-19
-------
vapor pressure levels are usually adjusted seasonally.
3.1.2 Gasoline Additives and Trace Components
Common gasoline additives and their functions are
described in the following paragraphs.
i Antik'nocks are added to prevent autoignition of air-
fuel mixtures. The most common ones are the aklyl lead
compounds tetraethyl lead (TEL) and tetramethyl lead (TML),
but manganese compounds are used as well. It is also common
practice to add lead extenders or scavengers such as tertiary
butyl acetate, ethylene dichloride, and ethylene dibromide
to improve the effectiveness of the lead compound (15).
Organophosphoras compounds, notably cresylidiphenyl-
phosphate (CDP), and methyldiphenyl phosphate (MDP),are
added as effective surface ignition suppressors (15).
Dyes are added for color purposes. Typical dyes are in
the range of 0.7 to 1.3 g/100 gallons and, with the excep-
tion of anthraquinone, are based on azochemistry (15).
Antioxidants are added to suppress gum formation (15).
Currently phenylenediamines in concentrations of 2 to 5
lb/1000 bbl are used for this purpose (15).
Metal deactivators are added to suppress metals (not-
ably copper) which can catalyze fuel oxidative processes.
The most important and widely used metal deactivator is N,N-
disalicylidene-l,2-propanediamine (15).
Corrosion inhibitors (normally carboxylic inhibitors or
phosphoric acid of high molecular weight, or their neutral-
ized derivatives) are added to prevent contamination by
rust, which frequently occurs from pipelines and storage
tanks (15).
Antiicers, which are added to prevent carburator icing,
are available in two classes, freezing-point depressants and
surface-active agents. Freezing-point depressants are
3-20
-------
alcohols with low molecular weight, such as methanol and
isopropanol in the range of 0.5 to 2.0 volume percent. The
most common surface-active agents are dimethyIformamide,
diproplene glycol, and hexylene glycol (15). They are used
in ithe range of 0.02 to 0.2 volume percent.
Carburetor detergents are added to improve engine
performance and reduce emissions. Among those used are
amine-neutralized alkylphosphates, imidazolines, succinimides,
amines, and amides (15).
Table 3-13 presents an analysis of 50 gasolines for
their trace elements (16). Only lead and sulfur were found
to be in concentrations greater than a few points per
million.
3.1.3 Overall Gasoline Composition
Because no comprehensive national surveys of gasoline
composition are available, only limited survey results are
presented. Table 3-14 shows results from three published
1970 studies by Morris and Dishart (17) . The reported
average composition is based on an analysis of 15 premium
gasolines. In 1975 Myers et al. (18) published a partial
tabulation of gasoline components based on 36 winter-grade
gasolines representing most of the brands and grades avail-
able in Detroit in January 1974. The overall analysis was
as follows:
Vol. % Standard deviation
Paraffins 68.3 3.2
Olefins 10.5 2.4
Aromatics 21.2 1.9
In 1969 Maynard and Sanders (19) published an analysis of a
typical premium-grade gasoline. Table 3-15 presents their
complete analysis of 233 identified hydrocarbons. All three
3-21
-------
Table 3-13. TRACE ELEMENTS IN GASOLINE (16)
w
l
NJ
to
Eltment
Be
Cd
As
V
Mn
Ni
Sb
Cr
7n
Cu
Se
H
AK
At
Ve
MR
01
r
I'll
R
C:i
Sn
Premium (22
S'
<0.001
<0. 001-0. 03
<0. 001-0. 002
0.001-f. .002
0.00? 0.03
0.003-1.5
< 0.003 -0.05
< 0.001-0. 34
0.001 2.00
0.011-0.25
<0.0f,
0.001-0.210
< 0.002- 0.03
<0. 001-0. 02
0.07 G. 00
<0. 002-0 004
0.02 0.80
<0. 001-0. 30
23S-7U3
10 360
0.0>:-0.26
<0. 02-0. -10
samples)
Avp,
PR/ml
0.013
0.086
0.1G
0.14
0.021
1.07
0.19
600
81
0.24
Regular (22
Range,
<0.001
<0.08
<0. 004-0. 009
<0.007
0.001-0.011
0.001-0.07
<0. 007 0.5
< 0.003-0. 03
0.010-2.00
0.010-0.40
<0.06
0.004-0.03
<0.54
<0.007
0.07-3.80
<0. 002-0. 01
0.05-1.10
<0. 00 1-2.0
190-750
10-040
<0. 00-3.0
<0.01-0.2
samples)
PS/ml
0.006
0.02
0.06
0.03
0.02
0.91
4'J4
177
Low lead (6 samples)
f'i'.-'rn\ >£/
<0.001
<0.04
<0 1
< 0^003
CO.C02-0.03
0.03-2.00 0
<0.iu
<0.0n5-0.016
0.20-0.50 0,
0 Oo -0.20 0.
<0.04
<0 1
0.3-13.0 G,
<0.007-0.!<0
<0.02
132-135 131
4-7-0 200
<0.2-0.7
-------
Table 3-14. GASOLINE COMPOSITION SUMMARY
DATA REPORTED AS WEIGHT PERCENT
123
Morris and Myers Maynard and
Paraffins Dishart(19) etal(18) Sanders(17)
Isobutane iC4 0.7
Normal butane nC4 4.8 7.0 4.3
Isopentane ;. ic5 8-5 9-3 - 10.2
Normal pen'tane nC5 3.4 4.5 5.8
Dimethyl butanes C6 2.0 1.4 ^ 2.0
Methyl pentanes C6 4.6 6.2 6.0
Normal hexane 2.0 3.3 1.5
Dimethyl pentanes 2.4 1.4 1.9
Methyl hexanes 5.9 6.3 3.2
Trimethyl pentanes 11.1 8.5 9.4
Normal heptane 1.2 2.0 2.0
Dimethyl hexanes 1.3 2.9 2.0
Methylethyl pentanes 1.4 0.4
Dimethyl hexanes 1.3
Trimethyl hexanes 1.4 0.4
N-octane 1.3
Naphthenes
Methylcyclopentane 2.0 1.8 0.6
Cyclohexane 0.9 0.2
Methyl cyclo hexane 1.2 1.0 0.3
Other saturates 7.5
Olefins
Methyl butene 2.5 2.5 1.3
Pentene 0.8 0.8 1.6
Methyl pentene 0.8 1.5 1.1
Other olefins 7.5 2.5 3.5
Aromatics
Benzene 0.9 1.5 0.8
Toluene 6.5 5.9 12.2
Ethylbenzene 1.3 1.3 1.7
Xylenes 8.8 5.9 7.3
Propylbenzene 1.4 0.3
Methylethylbenzenes 2.8 . 1.5 1.6
Trimethyl benzene 7.1 1.7 2.3
Other aromatics 5.2 2.3
Summary-Saturates 62 62
Olefins 11 9
Aromatics 27 29
3-23
-------
Table 3-15. DETAILED GASOLINE COMPONENT ANALYSIS (17)
Peak
Humbei
10
11
12
13
14
11
16
17
II
II
20
22
23
24
25
26
27
21
29
10
11
12
13
14
K
16
1)
11
19
40
41
42
41
44
45
46
«7
41
41
50
51
U
U
M
Component <
Piopane
debutant
Itobulylene
+ Bulene-1
Butane
Trant-2-butane
Neopenune
Cik-2-bulene
1'Melhyl l.bulene
Itopenlane
PgnluMul
2-MetliyM.l bul.idiene
Penluiie
Tiant*2-pentene
Cl»*2*pentene
2-Malhyl-2-butene
1> Dimethyl 1 butane
2.2-Oimelhylbutafle
Cydopentene
l-Melnyl l.pentene
+ 4-Melnyl-l-pentene
2.1-Dtmethyl 1-bulene
Cyclopenune
2.3-Dimetnylbulane
-f (4.Methy|.uant-2.pcmene)*
2-Methylpenlane
2.Melny|.]-peniene
3-Metnylpenlane
+ ene-l)
r (2-Elnyl-l.butene)
at-3-tieiene
Trans l-he»ene
1-Meltiylcydopentene
2-Methyl-2-pentene
}.Mtlhy|.cii-2-penltne
fl.Heiane
-r (4.4-Oimetriy|.l.penlene7
Trant-2-hexene
Ci>-2-ne>ene
l-Mathyl-lrana.2.penlane
4.4.0imethy1>trana-2.pentene
Mathylcydopenlane
+ (l.l-Dimeinyl.).pentene)
2.2-Dimelhylpenlane
f 2.1'Dimethy|.2-butene
* (2.3.3.Ttimetnyl-l.buiene>
Bcniene
2,4.Dimethylpentane
4.4-Dimethy|.ci»-2.penleno
2.2.1-TnmelriylDuUne
2.4-Dimotnyl-l.pefitene
l-Uelriytcyclopenlene
+ 2-MetRyl-ei>>heien«
2.4-Dimethy|.2.pentene
+ l-Ethyl-l-pentene
+ 3-MelnyM.heiene
I'.t.OimeltTyM.p^nfcaiM
t.M4lhrtMan»>.a>lM>
+ ttMtM l.htMIW
3.1 Dimalhtip«nlane
Cyclohemane
f (4 Melliy|.cit.2-n«iei>«l
4-Melhyl-l-rieMene
+ 4.2-D«iene
l-Methyl-2-elnyl.l.bulene
S^Uelltyl batt»-2-l«IB«fM(
CvclulMttviM
Boiling
Po.nl. -I'
-47.07
-11.71
-6.90
' -6.26
-0.50
O.U
9 50
1.72
K>0>
27.15
29. 1/
14.0'
K.O/
36.35
36.94
3J.V
41.24
49.74
44.74
54.14
51.U
56. 10
55.67
49. 2t
57 99
51.55
60.27
60.72
63.21
(1.49
MM
66.47
67.09
65.0
67.29
67.70
61.74
72.49
67.17
61.14
70.44
76.75
71.11
77.57
n.20
73.21
77.17
n.io
n.50
10.42
10. U
11.64
75.1
16
11.26
4.11
4
14.21
K
n.3i
H.06
10.74
17.31
U.7I
l'.5l>
b.l
M II
It w
CompoMtion.
*«l
0.01
0.3'
0 04
4.29
0.20
OOJ
O.I'
01?
ID 1'
V 4'j
>.'5
0.90
0.6'
0.96
0.46
0.11
0.11
C.04
0.08
0.51
1.55
0.11
3.76
0.22
2.23
0.11
0.12
0.04
0.27
0.37
1.51
0.11
0.15
0.34
Tiace
0.62
0.11
0.11
1.71
0.04
0.03
0.12
0.05
0.02
0.04
0.02
0.17
0.09
0.07
.u?
.UJ
Peak
Numbei
55
56
»
51
M
to
61
62
61
64
65
66
67
U
69
70
71
72
71
74
75
76
77
71
79
B
11
12
U
4
IS
16
17
U
19
90
fl
<2
1
M
tl
K
17
n
n
100
Ml
w
Component
2-Mclnylheiane
+ (5 Meiny|.cit-2-rie«ene)
2.1-Dimeinylpenlane
+ (I.l-Oimetnylcyclopenlane)
+ (3.4.0-2-pentene
|.Tranft-3-dimetltylcyclopentane
+ l-Heplene
f 2-EthyM-pentene
3-Clliylpvnljii«
-f 3 Mi)lliy|.!ient-2-lte»eno
l.Treni-2-dimelliylcyClopentane
2.2.4-Tomeinylpenlane
t (Tranfl-hepiene)
Ci»>3ena
+ 2-Memyl-2-he>ene
+ 3-Melltyl-lrani 3 neient
l-Elltyl 2-pentene
Trans-2-rteplene
n-Hepune
-f (3 Melhy|.ei»-2-he»ene>
2.3.0imethyl-2-pentene
+ Cit-2-heplene
Ki»-2-dimethylcydopentane
Methylcydoneiane
f 2.2-Dimemylnexane
+ I.l.l-Trimelhylcydopentane
2.3-Oime!nylne*ane
+ Elhylcyclopentane
2.4-Oiiiielhytneiane
2,2.1-Tnmethylpentane
l-Trani-2-at-4.uimetriylcydopentane
Toluene
3.3-Dimethylhexane
l-TranS'2.a»-3.tnmethylcydopentane
2.3,4-Tiimelrtylpenlane
2.3.1-Trimetnylpentane
1.1^-Trimelhylcydopenune
2.3-DKneinylhexane
+ 2-Melnyl-l-etnylpentane
2-Metnylheplane
4-Methymeplane
1.4-Oimelhylnexane
f (l-Cit-2-l'ans.4-lrirnelhyTran>-4-leliametriylcydop«nunt
2,2.5-Tiiinelhylheiane
+ (l-Cis-2-cis-4-liimf Ihylcydopanune)
1,1-Otmemylcydohexane
f l-TranM-dimetnylcydohemane
l-Oi-l-dtmelhylcydorie>ane
I'Meinyl-irans }-ethylcyclDpenlan«
2^.4-Tiimelhyllieiane
l-Meinyl.trans.2-elltylcydop«ntene
f l-Metiiyl-cii-3-tinylcydppenlane
Cydoneptena
l-Melliy|.|.ethytcydou«nUne
l-Trant-2-dimeinylcydorietane
Ocune
l^ii-4-dimethytcyclprMKane
1-Trant-l diioelhylcyclUi«iane
2.4.4 TiimelliyllieB*n»
IMP«upy4crvlap«nla«MI
2.J.l-liMitwliirHNia«iw
Poinl!"^'
90.05
19.5
17.71
17.15
17.9
11.15
11.73
91.95
10.5
90.77
13.64
94
93. a
94
91.1'
99.24
95.67
»5.75
95.3
15.44
13.53
to. 01
97.95
91.43
94
17.40
M.5
99.57
103.91
106.14
104. n
109.10
101.47
109.41
109.14
10971
110.61
111.97
110.2
111.47
114.76
111.71
115.61
115.65
117.65
117.71
11). 71
116.71
111.51
111.91
111.26
121.6
124.01
III
111.54
1)9.35
120.09
120.1
126.54
121.2
121.1
111.79
121.52
121.42
121-0
12V67
174.12
174.45
110.65
IK. 42
III.M
Composition.
1.41
1.17
1.77
0.27
0.27
1.16
0.16
4.51
0.16
0.11
0.04
0.06
1.96
0.12
0.09
0.11
0.60
0.50
0.21
0.04
12.20
0.10
0.06
2.26
2.21
0.09
o.to
0.41
0.22
0.16
0.01
0.63
.11
0.14
.01
O.U
0.11
1.07
0.01
0.02
0.12
0.11
0.04
0.04
0.02
1
.15
3-24
-------
Table 3-15 (continued). DETAILED GASOLINE
COMPONENT ANALYSIS (17)
*«
103
104
U5
K6
M7
iej
1(9
110
111
112
113
114
115
116
117
111
111
120
121
122
123
124
125
126
127
121
129
110
131
112
111
IM
IIS
116
117
IB
U)
.140
141
142
141
144
145
146
147
Ml
149
IK
111
IU
IU
IM
to
IU
i C4~p<~«.
2>£>,m«nyrhapun.
l-UtUiyt-cl«-4?-«ll>ftcrc»op«filan*
2,*-Dim«trtrtn»pt«f>«
+ 2,2. Miimtl fifth*! an*
2,?-Omiftnr<-)-*ihylp«nt*n«
f M.nmy,-4-«infirMjnn«
{.t-Dimcthrlhcpitnt
4~ (l-Cii-Z-dimttnytcyclontiiiVvc)
Propytcyctop«nUn«
Cthyicydoftcxinc
2,S-Oim«tnylh«ptcnt
-f LS-Chrnclhyihcpun*
CthyltMnziin*
1,4- Dime 1 r>yt- )-« thytp«nt«n«
J.tOtnulfiyih^pun*
1 . 1 ,} T i im*iny ky cMfiCJUuii]
2J>TruTM(nylh*«..nt
l-Cit-3 c^S-UtmttnytcyOoMxan*
2-M«lhxt-)-«my)f>«*ant
p-Xyttnt
t-Xyicnt
f (3.3,1 Tfim.|thy1f>«Mi>«}
Z.J-Dinntnyinijpuri*
i,4-Dim«(hyintpunt
m»ithy(ht*«n«}
2.2.4- Tnmctnylhipune
2.2.S-Tttfneinyttiepi4in»
+ Z.^.b-Trimeihyt^PtAn*
2,S.5-Tnm«lhylhtptine
+ 2,'M-Tiim*|hy1hfpUn«
1 »op* opxlbtni tnt
Nonant
3.3.$- T rimcthytM punt
Z.4.S-Tiimtthylh*pun*
4- 2.1.S-Tfim«iny,r>ffpuno
Pi opyib*ni«n t
2J,3> Tttf*m«trtytn«i»ni)
+ 2.6-DimtlhylocUnt
I-Mattiyl I-tihytt>«nitnt
1 -M thy1-4-« Ihylb«oi« n«
t,3,4-T(im«thythtpUn*
+ 3.4.4-TnmclnylhtpUn*
4- 3.4.5-T(im*tr>y.n«pl4int
l'Mttnyl-2-tlhyttxiniK'it
+ ^U*tr*lyition,v>«
4-UaUiylnon.w.*
.U3,VT(im«tlty1D«nz«n4t
?-W*t4-iytnort«n*
I*r1.euty1£i«ni»n«
UnidtnUii*d Cw iMkytalii port
|-M«th)rtnon*n«
1^,4- TnmcthytixinMM
c-Bu rylbcni «n«
1 tobvtybx ni«f»«
I'tHtVifl Jlttf HJ.XHUJU
DM**
1^,1- TmniTriifiimj.^
f 1-M.Hhy 1-4- ttopf I»pj*imii>«»»
|-Uithy17 lUptopytMnicn*
f Indmi*
M DMtfiytCMinKK.*
Unk}*ntrfi«d C,( alkytoio p««li
I MtiTiyl J ptopilbonnni
-*""""1
Pool. -C-
132.69
121.05
111.5
111.6
111.11
113.1
115.21
129.71
110.95
111.71
IK.O
136.0
116.19
116.71
117.3
116.63
137.61
IB. 41
131.0
IB. 35
119.10
140.46
140.5
. 140.6
142.41
141.26
141.0
144.11
144.41
147.U
147.1
IU
141
152.10
153
152.39
150.10
155.61
157
157
159.22
160.31
151.54
161.11
161.99
164
164
164
165.15
165.1
165.7
164.72
166.1
169.12
167.1
169.15
173.31
172.76
175.11
174.12
174.04
117.10
171.15
177
111.10
111.60
111.27
*<
0.01
. C.07
0.01
0.02
0.07
0.01
0.17
0.16
i.a
0.01
0.04
0.05
0.04
1.51
3.11
0.11
0.07
0.11
0.14
0.02
0.60
1.91
0.17
0.27
0.21
0.10
0.14
0.02
0.17
0.24
0.06
O.U
O.C
O.B
(.H
0.04
0.19
0.06
0.01
(.06
1.61
0.01
0.01
0.01
O.M
(.12
(.15
o.n
(.11
. (.15
p>ak
157
151
159
160
161
IU
161
164
165
IU
167
161
169
170
171
172
171
174
ITS
176
177
171
179
160
Tota* tatural
Tout otelmt
Total aiomal
Component
1.2-OiBinylbtnient
+ 1.4-D.elhylljeniene
t l.Mcirtyt-4 ivpiopylbcniene
l-Malfiyl-2-n'ptopyibenzene
l.l.Dimetny|.S.elnylbeniene
Unidentified d, alkylate peed
2-Memylmdane
1.4 Dimelhy|.?.emytbeniene
l-Melhylind«ne
l-Melliyl-l-terl-butylbeniene
+ unioentiliod CM alkylale peak
l.l.Diin«thyl.4.etliylbi..niun«
1.1 Diiiiul>iy|.?.i)lliylb.>ii/uiiii
f 1.2-Utiiitflliyl 4 ulliylbvruene
I.Uelhyl-4 ler|.tnitylbi..n»iie
1.2-Diinciliy|.3.elliyltwiiiene
Undecaiie
1.2.4.5-Tetiametnylbe.nzene
1.2.1.5-Telramcinylbeniene
liopentylbenlene
S-Uetnylmdane
4.Meliiylindene
Penlylb«nfene
1.2.1.4-TeUamelliylbenrene
Tel/alin
Napmnalene
1.3-Dimelhy|.5-lart.bulytb«nianc
.Doaecan.
let Aenljlied
identified
net ^anlili«d
nl. -C-
111 4?
111.30
111.75
1U.K
111.75
114
116.11
116.5
II9.?6
ID. 41
190.01
119.71
192. 76
193.11
115 19
196.1
ID 0
194 9
199
201
205.46
205.4
205.57
217.96
205.1
214.21
Tola compontnlt unidentified
TPUI.
*-.
009
0.05
0 U
(.02
(.a
t.v
(.a
(.13
(.»
( (4
(03
0 07
O.W
0 17
e.oj
(.11
o«
( 13
( 03
(.67
(.10
(.(?
(.05
62.10
7. 1C
21 50
1.70
KD.OC
3-25
-------
reports show similar saturate-olefin-aromatics fractions.
Mayrsohn and Bonamassa (20) published overall gasoline
analyses of 1970 gasolines sold in Los Angeles. Table 3-16
presents these 4ata. The aromatics content of these fuels
wasjhigher' than'shown in previous data, possibly because
more aromatic crudes are processed in Los Angeles. Also,
the aromatics level in regular gasoline was higher than in
the other grades. Normally, the olefins level depends on
the amount of cat-cracked and thermally cracked gasoline
present.
Because benzene is the most toxic volatile gasoline
constituent, its level is of particular interest. A 1976
NIOSH study of gasolines showed an average benzene concen-
tration of 1.24 volume percent (21). An October 1976 survey
of Gulf Oil gasoline showed an overall benzene level of 1.25
volume percent (22) . A nationwide survey of the benzene
content of gasoline during February/March 1977 revealed
concentrations ranging from 1.25 to 5 percent.* The annual
average was estimated to be about 2 percent. Table 3-17
presents the benzene content of gasoline blending components
from two refineries.
In summary, studies show that gasoline composition
varies widely as a function of crude oil source, refinery
processing configuration, and gasoline blending for each
gasoline grade. As the market for unleaded gasoline in-
creases, levels of aromatics generally increase as well
because the unleaded octane ratings of aromatics are relatively
high. Overall analyses are as follows: aromatics, 20 to 35
percent; paraffins, 60 to 70 percent; and olefins, 5 to 15
percent. 'The reported analysis of premium gasolines, by
carbon number, is as follows (25):
*
Telephone conversation with Dr. Leigh Short of the Depart-
ment of Chemical Engineering, University of Massachusetts,
in April 1977.
3-26
-------
Table 3-16. HYDROCARBON COMPOSITION OF
LOS ANGELES GASOLINES (20)
. . HYDROCARBON COMPOSITION OF "PREMIUM" FUEL
Refiner
Aromatic!
Parafflna
OleJina
A
Wt. Vol.'
39. 8 34. 0
52.4 58.6
6.2 7.2
B
Wl. Vol.
37.4 31.7
56.2 61.8
C
Wl. Vol.
% %
37.9 32.6
53.8 58.8
]
Wl.
%
38.9
55.6
D
Vol.
%
33.0
62.0
1
Wt.
%
37.1
58.8
E
Vol.
'1
31.1
65.0
Wl.
*
44.7
52.9
F
Vol.
%
37.8
59.8
G
Wt. Vol.
1 %
394 33.3
50.9 56.9
H
Wt. Vol.
% %
37.2 31.3
54.7 59.9
HYDROCARBON COMPOSITION OF "REGULAR" FUELS
Aromatic!
Parafflna
Oleum
28.
69.
1.
0
8
2
21.8
76.6
1.3
31.
57.
9.
9
6
0
26.2
63.8
9.9
28.2
63.9
7.0
a.
68.
7.
4
7
6
27.3
62.3
9.1
22.6
66.6
9.9
34.8
59.9
3.9
29.5 32.3 27.8
66.6 62.0 67.2
3.5 4.3 4.7
HYDROCARBON COMPOSITION OF "LOW LEAD" FUELS
Refiner
Aromatlci
Parafflna
Oletlna
E
Wt.% Vol.%
31.7 25.8
63.2 69.1
4.0 44
F
Wt.% Vol.t
G
Wl.t Vol.*
31.1 27.0
61.8 65.7
6.1 7.0
34.1 31.0
58.6 62.1
5.9 6.7
HYDROCARBON COMPOSITION OF NON LEADED FUELS
Refiner A D
_ Wt.t Vol.% Wt.% Vol.
Aromatic!
Parafilna
Oletlna
F H
Wt.% Vol.% Wl.ft Vol.%
43.9
56. 0
0.1
38.0
62.0
0.1
37.6
57. 8
2.8
32.3
64.0
3.3
40.6
64.0
4.6
35.3
58.9
5.2
41.6
52.7
4.6
33.6
60.3
6.2
COMPOSITE HYDROCARBON COMPOSITION OF VARIOUS FUEL GRADES
Aromatics
Paraffins
Olefins
Premium
Wt.% Vol.%
39.0 33.1
54.5 60.4
5.3 5.9
Regular
Wt.% Vol.%
30.5
62.7
5.6
25.2
68.4
5.9
Low Lead
Wt.% Vol.%
32.3
61.1
5.3
28.0
65.6
6.0
No Lead
Wt.% Vol.%
40.9 34. 8
55.1 61.2
3.1 3.5
3-27
-------
Table 3-17. BENZENE CONTENT OF GASOLINE BLENDING COMPONENTS (23)
u>
I
to
00
Heavy reformate
Raffinate3'
Straight-run naphtha
Pyrolysis gasoline
Light-fluid, cat-cracked
gasoline
Heavy-fluid, cat-cracked
gasoline
&
Hydrocracked gasoline
Hydrocracked reformate
Butane
Alkylate
Coker gasoline
Isomerized naphtha
Refinery A
Volume &
benzene
1-7
N.A.
1-3
2-8C
2-3
N.A.
N.A.
0
0
Refinery B
Volume &
benzene
0.5-1.5
.. 0.9
0.5-2.0
. 0.5-1.0d
0.7-2.0
0.1-0.4
0.5-2.0
0.5-1.5
0
0
a
b
c
d
e
f
From benzene-toluene-xylene extraction.
From steam cracking of gas oils.
Assumes no benzene extraction.
GS and C^+ gasoline; assumes benzene extracted from
Light hydrocrackate is sent directly to gasoline.
Reformed heavy hydrocrackate to gasoline.
gasoline.
-------
wt. %
C4 8
C5 18
C, 13
b
C? 15
-Cg 21
S 9
Other 16
The number of chemical compounds increases with increasing
carbon number. The octane rating characteristics of com-
ponents that determine the blending value in gasoline pools
are reviewed below.
a) Aromatics have very high clear octane ratings but
relatively poor lead improvement (see Table
3-8). Thus, they are ideally suited for unleaded
gasoline, and generally improve the octane rating
of a blend.
b) Naphthenes, or saturated-ring hydrocarbons, which
appear in high concentrations in straight-run
streams and hydrocracked gasoline, have low octane
ratings. Gasoline-boiling-range streams that are
high in naphthenes are typically reformed to
convert most of the naphthenes to aromatics, thus
raising the octane rating of the stream.
c) Paraffins vary greatly in octane ratings, depend-
ing on the number of carbon atoms and the degree
of branching in the molecular structure. This is
illustrated in Table 3-18 for C4 to Cg alkanes:
3-29
-------
Table 3-18. OCTANE RATING OF ALKANES AS A FUNCTION
OF MOLECULAR STRUCTURE (11)
. RON-CLEAR
\ ''.
. ' ' Number of methyl groups
Carbon
number 012 3
C4 94.0 102.1
C5 61.8 93.0
C, 24.8 73.4, 74.5 91.8, 104.3
b
C7 0 42.4, 52.0 92.8, 83.1, 80.8, 91.1 112.1
Cg 21.7, 26.8 55.5, 65.2, 71.3, 76.3 100.0, 109.6,
102.7, 106.1
The lead response of paraffins is excellent (see
Table 3-11), making them ideally suited for
leaded gasolines. Paraffins in straight-run
gasolines are not as highly branched as they are
in gasolines with more processing, and usually
have lower octane ratings. Reformate and alkalate
paraffins are typically highly branched and have
excellent octane values.
d) Olefins, which come mainly from straight-run, cat-
cracked, and thermally cracked gasolines, normally
exhibit octane properties similar to paraffins.
3.2 GASOLINE VAPOR ANALYSIS
Because of the wide boiling range of the constituents
of gasoline vapor, its composition will be much higher in
lower boiling point components than in corresponding liquid
gasoline. Vapor composition varies as a function of liquid
composition. McDermott and Killiany (26) presented the most
comprehensive gasoline vapor composition data found in the
literature search. This study included 95 gasoline vapor
samples taken by air sampling at marketing plants where
3-30
-------
gasoline is loaded into tank trucks for delivery to service
stations. These data, summarized in Table 3-19, show the C.
and lighter fraction of the gasoline vapor to be 45 volume
percent and the .C* and lighter fraction to be 81 percent of
the;total hydrocarbon vapor, respectively. Liquid gasoline
analyses, presented in Table 3-14, show 21 to 24 percent of
C_ and lighter components. The gasoline vapor analyses
reported by Jackson and Everett (27) and McEwen (27) in
Table 3-19 represent automobile fuel tank evaporative emis-
sions. The unusually high olefin levels reported in these
data indicate that the gasolines were atypical according to
available gasoline component information presented in sub-
section 3.1.1.
Gasoline vapor-liquid equilibrium is not just a hydro-
carbon system; it must include air, generally as the major
vapor component. Burklin et al (25) reported flash calcula-
tions on typical gasolines for summer and winter in Table
3-20. It is apparent that winter conditions resulted in a
far leaner hydrocarbon-air vapor.
Table 3-21 shows experimental data presented by Burklin
et al (25) showing gasoline vapor compositions under differ-
ent seasonal conditions. Since the quantity and composition
of gasoline vapors are dependent on such parameters as the
temperature and pressure of the containing system, the
composition and (RVP) of the gasoline, and the method of
vapor generation, these data do not show uniform trends.
Figure 3-2 shows the temperature dependence relationship
of hydrocarbons evaporated from gasoline, assuming the
system is in equilibrium (24). Figure 3-3, however, shows a
composition gradient in the vapor space of service station
gasoline storage tanks. This concentration gradient indicates
that only the vapor space adjacent to the vapor-liquid
3-31
-------
Airborne gasoline
vapor composition
00
I
00
NJ
Compound
Reference
Alkanes
Propane
Normal butane
Isobutane
Isopentane
Normal pentane
Cyclopentane
DimethyIbutane
2-methyIpentane
3-methylpentane
Normal hexane
Methyl cyclopentane
2,4-dimethylpentane
2,3-dimethylpentane
2,2,4-trimethylpentane
Alkenes
Isobutylene
2-methyl-l-butene
2-methyl-2-butene
Methyl-butenes
Aromatics
Benzene
Toluene
Xylene (p,m,o)
Total percent
Boiling
point, °C
-42.1
- 0.5
-11.7
27.9
36.1
49.3
58.0
3
7
,7
60,
68,
68,
71.8
80.3
89.8
99.2
6.9
31.2
37.0
80.1
110.6
142.0
Mean volume
percent
Standard
deviation
0.8
38.1
5.2
22.9
7.0
7
7
0,
0,
2.1
1.5
1.5
1.3
0.4
0.7
0.5
1.1
1.6
1.2
0.7
1.8
0.5
92.1
26
Data from McDermott and Killiany (26).
Data from Jackson and Everett (27). .
Data from McEwen (27) for two different gasolines
7
,5
1.1
5.7
1.9
6.1
4.0
0,
0,
1.3
0.9
0.9
0.4
0.5
0.6
0.5
1.5
2.1
1.7
0.4
1.3
0.6
Volume
percent
27
16.
6.
23.
7.
1.
1.
1.
0.
13.
7.
5
5
2
2
7
9
1
7
6
0
27
30.
2.
26.
8.
2.
3.
1.
3.
2.
5
7
4
6
6
4
8
2
9
27
».
48.
3.
20.
6.
1.
2.
1.
2.
, 2'.
5
6
3
9
6
4
5
2
0
12.4
7.9 5.5
0.4 0.4 0.3
0.4 0.9 0.3
92.7 91.3 95.1
-------
Table 3-20. SEASONAL COMPOSITIONS OF GASOLINE AND
.ITS VAPORS IN MOLE PERCENT (25)
Air
C-
C8
C9
Ci o
Total
RVP
Temp. , °F
Winter
Liquid
Composition
-
12.8
23.3 '
14.1
19.6
17.2
6.5
6.5
100.0
13.0
Gasoline
Calculated
Vapor'!-)
Composition
76.2
15.1
7.0
1.1
0.5
0.1
-
_
100.0
40
Average of
Summer Vapor
Compositions
58.4
20.9
13.6
7.1
(2)
100.0
80
(1) Vapor in equilibrium with liquid assuming a vapor to
. liquid ratio of 3.0 at 40°F.
(2) Average of ten typical compositions
3-33
-------
Table 3-21. EXAMPLE GASOLINE VAPOR COMPOSITIONS (25)
Month
i
Location
Ambient Temp.
Compound
Air
Methane
Ethylene
Ethane
Propane
Isobutane
Butene
N-butane
Isopentane
Pentene
N-pentane
Hexane
Heptane and
Feb .
Las Vegas
45°F
78.4
0.3
0.0
0.0
0.4
3.1
-
10.2
4.3
-
1.8
1.0
higher 0.4
Oct.
-
-
70.9
0.0
0.1
0.0
0.5
1.8
-
9.6
10.8
-
1.1
2.9
2.2
May
-
-
Volume %
67.5
0.4
0.0
0.0
1.9
7.8
-
10.9
5.4
-
3.9
1.4
0.7
May
-
-
87.7
0.0
0.0
0.0
0.1
0.2
-
2.6
5.1
-
1.1
1.6
1.2
-
-
58.1
-
-
0.6
2.9
3.2
17.4
7.7
5.1
2.0
3f\
. 0
Summe
-
-
58.4
-
0.8
1.3
13.6
7n
. 1
3-34
-------
O
cc
UJ
o.
to
1
CD
I/I
o
o
lu
O
_l
CL
tt
o
16
14
12
10
40
50
60
70
80
90
TEMPERATURE, °F
Figure 3-2. Sensitivity of displaced loss to
temperature at various values of RVP (24).
3-35
-------
o
o
01
1 234 5 6 .7
DEPTH BELOW TOP OF DROP TAPE
Figure 3-3. Hydrocarbon vapor composition in
underground tank.
3-36
-------
interface is saturated with hydrocarbons and that the
hydrocarbon losses estimated in Figure 3-2 may be high (25).
Appendix A presents detailed gasoline vapor composition
for gasoline trijck loading terminals, including test results
for; top arid bottom loading operations for each season (28).
Approximately 140 compounds are identified.
Table 3-22 presents the airborne concentration of
gasoline additives. The concentration of these additives in
the vapor is a function of the hydrocarbon vapor concentra-
tion.
3-37
-------
TABLE 3-^22
Airborne Concentration of Gasoline Additives
Calculated
Airborne
Concentration
With 500 ppm Fecfcral OSHA
Concentration in of Airborne 8-Hour
Additive Liquid Gasolinea Ga soline Standard
Tctraethyl-/
tetramethyllead
Ethylone dibromidc.*3
1 . 5-3. 18 grams
per gallon
80-150 ppm by
0. on t pv.. /M3
(as Pb)
0. OH -.-m
0. 075 rm
(as Pb)
?. 0 Dom
;/M3
1
I volume
u>
oo
Ethylene dichloride 150-300 ppm by 0. 15 pprn 50 ppm
volume
aLcaded grades only.
^Etbylene dibromide was identified as a carcinogen in laboratory rodents in June 1*975 by
the National Institute for Occupational Safety and Health. Xo human cancers from exposure
to tliis substance are known. 1 his- exposure standard is based on acute health effects, not
this animal carcinogenicity. TLV^being revised to 1 mg/m3 for 15 min.
-------
REFERENCES TO SECTION 3
1. Sterba, M.J. Alkylation in Chemical Process Technology
Encyclopedia. D.M. Considine, ed. McGraw-Hill, New
York. 1974.
2. Arthur D. Little, Inc. The Impact of Lead Additive
Regulations on the Petroleum Refining Industry: Vol.
II. EPA-450/3-76-016-b. May 1976.
3. Mayer, E.M. Aromatics Production, in U.S. Petrochemi-
cals A.M. Brownstein, ed. Petroleum Publishing Co.,
Tulsa, Oklahoma. 1972.
4,
5,
6,
8,
9,
10.
Shelton, E.M. Motor Gasolines, Winter 1976-77 ERDA,
BERC/PPS-77/3, Bartlesville, Oklahoma. June 1977.
Shelton, E.M. Motor Gasolines, Summer 1976. ERDA,
BERC/PPS/77-1, Bartlesville, Oklahoma. January 1977.
Arthur D. Little, Inc. The Impact of Lead Additive
Regulations on the Petroleum Refining Industry, Vol. I.
EPA-450/3-76-016-a. May 1976.
Pollitzer, E.L., J.C. Hayes, and V. Haensel. The
Chemistry of Aromatics Production via Catalytic Reform-
ing, in Refining Petroleum for Chemicals. L.J. Spillane,
and H.P. Leften, eds. In American Chemical Soc. Ad-
vances in Chemistry. Series 97, Washington, D.C.
1970.
1976 Refining Process Handbook.
September 1976.
Hydrocarbon Processing.
Whittington, E.L., J.R. Murphy, and I.H. Lutz. Catalytic
Cracking - Modern Designs in American Chemical Society,
Division of Petroleum Chemistry, Inc., 17(3). July
1972.
Glasgow, A.R., et al. Components of Gasoline Produced
by Catalytic Cracking. Industrial and Engineering
Chemistry, 41(10). October 1949.
3-39
-------
11. Hutson, T., and R.S. Logan. Estimate Alky Yield and
Quality. Hydrocarbon Processing. 54(9). September
1975.
12. Ward, J.W. The varieties of Hydrocracking. Hydrocarbon
Processing,;. 54 (9) . September 1975.
13.' Sterba, M.J. Petroleum Processing in Chemical Process
Technology Encyclopedia, D.M. Considine, ed. McGraw-
Hill. New York. 1974.
14. Rossine, F.D., and B.J. Mair. The Work of the API
Research Project 6 on the Composition of Petroleum.
Presented at Fifth World Petroleum Congress. June 3,
1959.
15. Polss, P. Gasoline Additives. American Chemical
Society. Division of Petroleum Chemistry, 17(3). July
1972.
16. Jungers, R.H., R.E. Lee, and D.J. von Lehinden. The
EPA National Fuel Surveillance Network, I. Trace
Constituention Gasoline and Commercial Gasoline Fuel
Additives. Environmental Health Perspectives. Vol.
10. April 1975. pp. 143-150.
17. Morris, W.E., and K.T. Dishart. Influence of Vehicle
Emission Control Systems on the Relationship Between
Gasoline and Vehicle Exhaust Hydrocarbon Composition.
ASTM Special Technical Publication 487. American
Society for Testing and Materials. Philadelphia,
Pennsylvania. 1971.
18. Myers, M.E., J. Stollsteimer, and A.M. Wims. Determination
of Hydrocarbon Type Distribution and Hydrogen/Carbon
Ratio of Gasolines by Nuclear Magnetic Resonance
Spectrometry. Analytical Chemistry 47(12). October
1975.
19. Maynard, J.B., and W.N. Sanders. Determination of the
Detailed Hydrocarbon Composition and Potential Atmos-
pheric Reactivity of Full-Range Motor Gasolines. J of
Air Pollution Control Assoc. 19(7). July 1969.
20. Mayrsohn, H, and F. Bonamassa. Hydrocarbon Composition
of Los Angeles Gasolines 1970. American Chemical
Society Division of Petroleum Chemistry 16(4). Septem-
ber 1971.
3-40
-------
21. Hartle, R., and R. Young. Occupational Exposure to
Benzene at Service Stations. National Institute for
Occupational Safety and Health. Cincinnati, Ohio.
June 1976.
22. Runion, H.E1^. Benzene in Gasoline II. - Gulf Science and
i Technology'Co. American Industrial Hygiene Assoc.
* 38(3). August 1977.
23. Burr, R.K. Benzene Extraction from Motor Gasolines.
Internal Memorandum to J.F. Durham. U.S. EPA. June
21, 1977.
24. Polss P. Gasoline Additives. American Chemical Society,
Division of Petroleum Chemistry 17(3). July 1972.
25. Burklin, C.E. ,et al. A Study of Vapor Control Methods
for Gasoline Marketing Operations, Vol. II. EPA-450/3-
75-047-b.
26. McDermott, H.J., and S.E. Killiany. Quest for a Gasoline
TLV. Presented at 1976 American Industrial Hygiene
Convention, Atlanta, GA. May 12-16, 1976.
27. National Academy of Sciences, Vapor-Phase Organic
Pollutants. Washington, D.C. 1976.
28. Walker, D.C., and H.W. Husa. Demonstration of Reduced
Hydrocarbon Emissions from Gasoline Loading Terminals.
EPA-650/2-75-042. U.S. EPA, Washington, D.C. June
1975.
3-41
-------
4*0 GASOLINE TOXICITY EVALUATION
i
The preceding sections of this report have character-
ized gasoline as a highly complex mixture of relatively
volatile hydrocarbons and additives. Its composition varies
considerably as a result of crude oil characteristics,
processing techniques, seasonal requirements, and climate.
The composition of gasoline vapor depends on the composition
of the liquid and the method used to generate the vapor.
The intrinsic characteristics and quantitative variability
of gasoline and gasoline vapor contribute to the difficulty
involved in assessing the impact of gasoline exposure on
public health; therefore, the toxicity evalution is approached
in three steps: 1) health effects associated with gasoline
exposure are described as a function of the toxicity of the
hydrocarbon components of the gasoline, 2) health effects
associated with gasoline vapor inhalation are assessed, and
3) epidemiological studies related to gasoline vapor expos-
ure are reviewed.
Gasoline contains four major groups of components:
paraffins, olefins, naphthenes, and aromatics. Historically,
aromatic hydrocarbons have been the most significant from
the toxicological point of view. Benzene is the most
hazardous component in the aromatic fraction of gasoline
because of its physical and chemical properties, its low
TLV, and especially its leukem ogenicity. Other components
of the series, including toluene, xylene, and trimethyl-
benzene, are considerably less toxic than benzene, but
4-1
-------
evidence of adverse physiological effects and their struc-
tural similarities have prompted thorough toxicological
assessment. The severity of chronic toxicity has caused so
much attention to be focused on benzene and its derivatives
that the contribution of nonaromatic constituents to the
overall toxicity of gasoline may have been underestimated.
For an accurate evaluation of possible health hazards from
exposure to gasoline, consideration must be given to both
its aliphatic and aromatic hydrocarbon content. Generally,
olefins and naphthenes lack the biological and chemical
properties that warrant their consideration as significant
environmental health hazards. However, toxicological and
epidemiological evidence suggests that exposure to alkanes
can cause chronic neurological disorders. The toxicologic
importance of alkanes is further emphasized by the criteria
on which NIOSH bases its recommended standard for occupa-
tional exposure to Cc to C0 alkanes. The proposed new
D o
maximum allowable concentrations for pentane, hexane,
heptane, and octane are as low as the current limits for
toluene and xylenes.
This toxicological evaluation addresses each chemical
family individually. Components that represent major health
hazards are identified and their toxicities characterized.
Because of its objectives, this toxicity assessment reviews
only the effects associated with environmental exposure to
gasoline by inhalation (the most prevalent route).
4.1 GASOLINE COMPONENT TOXICITY
4.1.1 Paraffins
The principal paraffins in gasoline are saturated,
aliphatic'hydrocarbons that have three to eight carbon atoms
per molecule. The lighter weight members of the series,
propane (C-j) and butane (C4), are relatively inactive
4-2
-------
toxicologically and their only effect is that of simple
oxygen-replacing asphyxiants. These gases can be tolerated
in high concentrations in inspired air without producing
significant physiologic effects. Generally, alkanes from
pentane (Cc) through the octanes (C0) show increasingly
J O
strong narcotic properties. Narcotic effects may be ac-
companied by exhilaration, vertigo, headache, anorexia,
incoordination, and nausea. For many years, narcosis and
these nonspecific symptoms were the only effects attributable
to acute alkane exposure. Recent toxicologic and epidemio-
logic evidence, however, suggests that acute intoxication by
these alkanes involves a transient central nervous system
depression and that chronic intoxication may lead to the
development of the more persistent effect of polyneuropathy
(1). Polyneuropathy usually has been attributed to normal
hexane, but evidence suggests that this neuropathy also can
be caused by other alkanes and their isomers (1,2,3,4).
Alkane vapors are mildly irritating to mucous membranes, and
the irritation increases in intensity from pentane to octane.
Generally, the heavier paraffins above octane are insuffi-
ciently volatile to warrant serious consideration as vapor
hazards under normal conditions. Table 4-1 summarizes the
effects of alkane vapor exposure on humans, and Table 4-2
summarizes the effects on experimental animals.
Polyneuropathy caused by hexane exposure is documented
extensively in the literature (Ref. 1 through 7), but
definitive epidemiologic data or exposure studies demonstrat-
ing the neurotoxicity of pentane, heptane, or octane are
lacking. In a number of studies, however, the organic
mixture thought to cause polyneuropathy contained consider-
able quantities of one or more of these alkanes as components
(2,3,4). Gaultier et al. (4), for example, reported that
4-3
-------
Table 4-1. EFFECTS OF ALKANE VAPOR EXPOSURE ON HUMANS
A1 kane
Pentane
Hexane
Hexane
Hexane
Hexane
Hexane
Hexane
Hexane
Heptane
Heptane
Heptane
Heptane
Heptane
Heptane
Octane
Subjects
3-6 men and
women
3-6 men and
women
6 men and
women
93 men and
women
3-6 men and
women
3 women
11 men and
women
4 men and
women
3-6 men and
women
3-6 men and
women
3-6 men and
women
3-6 men and
women
3-6 men and
women
3-6 men and
Exposure
Concentration
and duration
Up to 5000 ppm
10 min
5000 ppm
10 min
2500-1000 ppm
10-12 hr/d
2500- 500 ppm
2000 ppm
10 n1n
1300-650 ppm
8-10 hr/d
2-10 months
1000-500 ppm
3-6 mon
not available
5000 ppm
15 nln
5000 ppm
7 min
5000 ppm
4 min
3500 ppm
4 m1n
2000 ppm
4 m1n
1000 ppm
6 min
Effects
No symptoms
Marked vertigo, giddiness
Drowsiness 1n 0.5 hr, fatigue, loss of appetite in some,
paresthesia in distal extremities
Sensory 1mpar1ment in distal portion of extremities, muscle
weakness in 13, cold sensation of extremities in some, blurred
vision, headache, easy fatigability, anorexia, weight loss at
onset of polyneuropathy, muscular atrophy, demyelination and
axonal degeration of peripheral nerves.
No symptoms
Headache, burning sensation of face, abdominal cramps, numb-
ness, paresthesia, weakness of distal extremities, bilateral
foot and wrist drop, absence of achilles tendon reflexes,
fibrillation potentials, decreased conduction time in motor
and sensory nerves, denervation-type Injury of muscles,
numerous neurophathologic changes
Fatigue, anorexia, paresthesia in distal extremities, muscular
atrophy
Peripheral neurophathy, reduced motor and sensory nerve con-
duction velocities, knee-jerk and Achilles tendon reflexes
absent, muscular atrophy, demlnished sensations of heat and
touch, pathologic abnormalities in muscles and nerves
Harked vertigo, 1ncoord1nat1on, hilarity for 30 min .
Marked vertigo, 1ncoordinat1on of space, hilarity 1n some
Marked vertigo, Inability to walk straight, hilarity
Moderate vertigo
Slight vertigo
Slight vertigo
No Data Available
I
Ref-
enence
8
8
2
7
8
5
2
6
8
8
8
8
8
8
4-4
-------
Table 4-2. EFFECTS OF ALKANE VAPOR EXPOSURE ON ANIMALS
tn
Alkane
Pentane
Pentane
Pentane
Pentane
Pentane
Pentane
Pentane
Hexane
Hexane
Hexane
Hexane
Hexane
Species
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
No.
1
4
1
1
4
4
1
1
1
Exposure
concentration
and duration
129,200 ppm
37 min
128.000 ppm
5 min
108,800 ppm
26 min
102,000 -
68,000 ppm
2 hr
91 ,800 ppm
66 m1n
64,000 ppm
5 min
32,000 ppm
5 min
64,000 ppm
5 min
51,120 ppm
9 m1n
42,600 ppm
127 m1n
42,600 -
34,080 ppm
2 hr
39,920 ppm
127 min
Effects
Decreased respiration rate, loss of reflexes, death by
37 min of exposure
Irritation, deep anesthesia, respiratory arrest In 1 by
4.75 min of exposure
Lying down by weakened reflexes
Lying down
Temporary lying down
Irritation, anesthesia during recovery period
Anesthesia during recovery period
Irregular respiratory pattern, respiratory arrest by
2.5 - 4.5 min
Death after spasms, no narcosis
Loss of reflexes, death
Death
Death
Ref-
erence
9
T 1 ... ..
9
12
9
11
11
11
9
9
12
9
-------
Table 4-2 (continued). EFFECTS OF ALKANE VAPOR EXPOSURE ON ANIMALS
Alkanes
Hexane
Hexane
Hexane
Hexane
Hexane
Hexane
Hexane
Hexane
Hexane
Heptane
Heptane
Heptane
Species
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
No.
1
4
4
7
6
19
6
4
4
Exposure
concentration
and duration
34,080 ppm
123 m1n
32,000 ppm
5 min
28,400 ppm
2 hr
16,000 ppm
5 m1n
8000 ppm
5 min
1000-2000 ppm
6 d/wk, 1 yr
500 ppm
6 d/wk, 1 yr
250-2000 ppm
6 d/wk, 1 yr
250 ppm
6 d/wk, 1 yr
64,000 ppm
5 m1n
32,000 ppm
5 min
18,300 ppm
2 hr
Effects
Light narcosis
Deep anesthesia
Lying down
No anesthesia
No anesthesia
Marked abnormal posture and muscular atrophy and degenera-
tion; in electromyographic tests, fibrillation at rest,
complex NMU voltage and high amplitude NMU voltage during
movement, and weakened interference waves during strong
contractions; increased electrical reaction time; reversal
of flexorextensor chronaxy ratio
Abnormal posture and muscular atrophy
Higher strength-duration curve with increased concen-
trations
Slightly abnormal posture and muscular atrophy; in elec-
tromyographic tests, some fibrillation at rest
Respiratory arrest in 3 by 3.75 m1n of exposure
Irregular respiratory pattern
Death 1n 2 hr
Ref-
erence
'9
11
12
11
11
13
13
13
13
11
11
12
-------
Table 4-2 (continued). EFFECTS OF ALKANE VAPOR EXPOSURE ON ANIMALS
i
-j
Alkanes
Heptane
Heptane
Heptane
Octane
Octane
Octane
Octane
Octane
Octane
Octane
Octane
Species
Mice
Mice
Cats
(decere-
brated)
Mice
Mice
Mice
Mice
Mice
Mice
Mice
Mice
No.
4
4
4
1
Exposure
concentration
and duration
16,000 ppm
5 min
9760 ppm
2 hr '
24,400 -
6100 ppm
5 min
32,000 ppm
5 min
16,000 ppm
5 min
12,840 ppm
185
10,700 ppm
2 hr
8560 ppm
55 min
7490 ppm
2 hr
6634 ppm
1 yr
5350 ppm
48 min
Effects
No anesthesia
Lying down
Decreased blood pressure during exposure, rapid return
to normal during recovery period; initial increased
respiration, then decreased
Respiratory arrest in 4 by 4 min of exposure
Respiratory arrest in 1 during recovery period
Decreased respiration rate, death by following day
Loss of reflexes
Narcosis
Lying down
Lying down
No narcosis
-\t
Ref-
erence
11. ... ...
12
14
11
11
9
12
9
12
9
9
-------
the solvent responsible for polyneuropathy in five employees
in the belt-manufacturing industry contained only 5 percent
hexane, whereas it contained 14 percent heptane and 80
percent pentane.-. Data from animal investigations support
the hypothesis that the concentration of an alkane required
to cause the development of toxic effects decreases as the
carbon number of an alkane increases (9,10,11). In addition,
comparative inhalation studies with experimental animals
suggest that straight-chained alkanes are generally more
toxic than their branched isomers (12). It is not unreason-
able to believe, therefore, that the different alkanes may
elicit similar toxic effects. This philosophy is reflected
in NIOSH's criteria for a recommended standard for occupa-
tional exposure to C,. to CA alkanes (1) . Since exposure to
only one alkane is infrequent., NIOSH has recommended a time-
weighted average concentration of 350 mg/m as the environ-
mental limit for pentane, hexane, heptane, octane, and total
alkanes (mixtures). On a volume/volume (v/v) basis, these
concentrations are equal to about 120 ppm pentane, 100 ppm
hexane, 85 ppm heptane, and 75 ppm octane. NIOSH also
recommends a ceiling limit of 1800 mg/m (about 610 ppm
pentane, 510 ppm hexane, 440 ppm heptane, and 385 ppm octane).
Because no studies were found that correlate environmental
concentrations of pentane, hexane, heptane, and octane with
observed toxic effects, these maximum allowable concentrations
(although designed to protect occupational populations over
a working lifetime) may serve as a means of estimating the
relative public health hazard associated with atmospheric
exposures to alkanes. In view of the proposed lower threshold
limit values, the toxic effects attributed to certain alkanes,
and the proportion of aliphatic hydrocarbons in gasoline
vapor, careful consideration should be given to the toxic
4-8
-------
potential of the paraffinic components of gasoline.
No studies were found to suggest that any of the
aliphatic hydrocarbons are related to carcinogenic, mutagenic,
or teratogenic effects in humans or experimental animals,
nor, is there any reason to suspect that they will be found
to produce such effects because these compounds are not
chemically related to materials known to have carcinogenic,
mutagenic, or teratogenic effects.
4.1.2 Olefins
Olefins (also referred to a-alkenes) are unsaturated,
aliphatic hydrocarbons. In general, they lack the biological
properties that would cause them to be considered environ-
mental health hazards. These compounds seem to cause no
more than simple asphyxia and weak anesthesia. Table 3-19
lists the principal olefins commonly present as 0.5 percent
or more of the total gasoline vapor composition. Additively,
the various olefins may comprise between 5 and 15 percent of
the total hydrocarbon composition of gasoline. The chemical
and physical properties of these hydrocarbons and their
potential to react biochemically, as warranted by their
unsaturated structure, do not appear to be of significant
consequence to elicit adverse effects on health. Threshold
limit values have not been established for any of these
hydrocarbons. Thus, in the absence of any definitive toxico-
logic, epidemiologic, or occupational evidence suggestive of
biological action, it is impossible to estimate the risk of
developing adverse health effects from exposure to olefins.
4.1.3 Naphthenes
Naphthenes are saturated or unsaturated alicyclic
hydrocarbons. Toxicologically, they resemble aliphatic
hydrocarbons, in that they act as general anesthetics and
central nervous system depressants with a relatively low
4-9
-------
order of acute toxicity. Massive acute exposure that
results in prolonged unconsciousness, anoxia, and convulsions
may cause central nervous system sequelae similar to those
described following exposure to volatile aliphatic.hydro-
carbons (1'5) . No evidence was found to indicate that
alicyclic hydrocarbons are specific hematopoietic toxicants.
Cumulative toxicity from repeated exposure to low atmos-
pheric concentrations is unlikely because naphthenes do not
tend to accumulate in body tissues or elicit any pathological
changes. The contribution of naphthenes to the overall
toxicity of a hydrocarbon mixture such as gasoline is
minimized by the small number and relatively low concentra-
tions of naphthenes present in modern gasolines and gasoline
vapor. Because of their low octane characteristics, napthenes
(which are found in considerable proportions in straight-run
gasolines) are reformed into high-octane aromatics and
branched aliphatic hydrocarbons. Tables 3-14, 3-15, and
3-16 list the major naphthenic components of gasoline, and
Table 3-19 lists those of gasoline vapor.
Very limited published data were found regarding the
effects of repeated exposure to vapors from these compounds.
Based exclusively on animal exposures to particular compounds,
the effects of chronic intoxication are "totally lacking,"
"nonspecific," or simply "fatal." No epidemiological or
occupational evidence was found to indicate that naphthenes
have any systemic effects. Reportedly, these compounds,
once absorbed, are detoxified and excreted in the urine in
the form of glucuronides and sulfates. No general relationships
have been established correlating the degree of toxicity
with the structural characteristics of this group of hydro-
carbons (e.g. the number of carbon atoms, degree of unsaturation,
4-10
-------
amount of branching, etc.)
In sufficent concentrations, naphthene vapors cause
irritation to mucous membranes. The saturated hydrocarbons
are generally less irritating than the corresponding un-
saturated 'compounds (15). No studies were found regarding
the carcinogenic, mutagenic, or teratogenic potential of any
alicyclic hydrocarbons.
4.1.4 Aromatics
The distinguishing characteristic of aromatic hydro-
carbons is the benzene nucleus. Benzene, the simplest
member of the aromatic series, has become most significant
toxicologically because of the severe systemic injury that
can result from the inhalation of its vapors. The carcino-
genic potential and specific toxic effects of benzene on the
hematopoietic system are well documented. Experimental
evidence indicates, however, that the alkyl derivatives are
not capable of inducing these effects and that benzene is
unique among the aromatic hydrocarbons as a myelotoxicant.
Thus benzene, which is a constituent of all motor gasolines,
should be considered the preponderant factor in the toxico-
logic assessment of gasoline vapor.
Because of the volatility of benzene, the primary route
of exposure is by vapor inhalation. High concentrations of
benzene, like most organic solvents, can cause depression of
the central nervous system. Symptoms are acute narcosis,
accompanied by drowsiness, vertigo, nausea, and headache,
which may extend to respiratory paralysis, unconsciousness,
and death, with or without convulsions. Benzene is no more
narcotic than other aromatic or aliphatic components of
gasoline,'however. The effects of acute benzene narcosis
are usually completely reversible unless the initial severity
of exposure causes pathologic changes. Reportedly, chronic
4-11
-------
effects of benzene intoxication can arise and persist long
after an acute exposure has occurred. It appears that
individual response to acute benzene exposure varies con-
siderably. ;
t Chronic benzene intoxication, which is characterized
primarily by a disturbance of the hematopoietic system, is
much more toxicologically significant. This anomaly can
affect a number of blood parameters, including erythrocyte
count, hemoglobin, mean corpuscular volume of red blood
cells, platelet counts, and leukocyte counts. Reportedly,
hematologic abnormalities have developed in humans as a
result of repeated exposure to benzene concentrations rang-
ing down to 105 ppm and 60 ppm (18,19). According to
Pagnotto's data (20), suggestive but inconclusive hemato-
logical changes were noted from exposure to benzene concen-
trations as low as 20 to 25 ppm in rubber coating plants.
Leukopenia and other blood disorders have been demonstrated
in experimental animals chronically exposed to benzene
concentrations of 40 to 50 ppm and 80 to 88 ppm (21,22,23).
A number of other investigators have cited cases of chronic
benzene poisoning resulting in hematological effects (24,25,
26).
The onset of clinical manifestations of chronic benzene
intoxication tends to be insidious and is characterized by
such nonspecific symptoms as headache, fatigue, anorexia,
vertigo, irritability, and nervousness. Most recorded cases
of chronic benzene poisoning have been quite advanced at the
time of diagnosis. Early blood examinations may indicate
anemia, leukopenia, and thrombocytopenia; however, sometimes
all three' cell lines either are not affected or they are not
affected to the same extent. Eosinophilia or leukocytosis
may be present, and immature cells may be observed in the
4-12
-------
peripheral blood. As the condition progresses, bone marrow
may become hypoplastic or aplastic in a manner that does not
always correlate well with the peripheral blood picture, the
nature .,of the exposure, or the prognosis. In some instances
of chronic" benzene poisoning, shortened red cell survival or
extramedullary hematopoiesis is evident, as are injurious
effects on the liver and kidneys.
The existence of a causal relationship between benzene
and aplastic anemia has long been accepted. Recently,
however, much attention has been focused on the leukemogenic
potential of benzene. The first clearly established case of
leukemia reportedly due to chronic benzene exposure occurred
in Italy in 1928 (27) . Since then, numerous cases of leukemia
associated with exposure to benzene have been cited in the
literature (29,30,31,32,33). It is now generally agreed
that benzene can cause various forms of leukemia, which can
arise with or without a previous history of aplastic anemia
(33). Chronic myelogenous leukemia occurs most frequently
with benzene exposures, but acute myelogenous and acute and
chronic lymphocytic varieties are known to occur as well
(34). Erythroleukemia has also been associated with chronic
benzene exposure (28,34).
Knowledge of the carcinogenic potential of benzene has
been gained primarily through the experience of human ex-
posure. Toxicological testing of animals has not been an
effective means of assessing the carcinogenicity of benzene.
In animal studies, the most consistent physiological response
to benzene has been leukopenia (16,17,21). Similarly,
scientific investigations attempting to relate the metabolic
products of benzene to its injurious effects on the hematopoietic
system have not been successful. Interestingly, alkylation
of the benzene ring markedly alters the metabolism and
4-13
-------
apparently significantly reduces the myelotoxic and leukemo-
genic potential.
Benzene is rapidly absorbed into the blood during vapor
exposure, and, because of its lipid solubility, tends to
distribute itself primarily in fatty tissues. Approximately
50 percent of absorbed benzene vapor is eliminated in
exhaled air. Trace amounts are eliminated in the urine, and
probably a limited amount through the skin. The remainder
is metabolized to more water-soluble phenolic compounds by
the liver (via oxidation). The primary metabolite is
phenol, which is excreted in the urine in both the free form
and as a conjugate with sulfuric or glucuronic acid.
The incidence of benzene-induced chromosomal aberrations
in peripheral blood lymphocytes and bone marrow has received
considerable attention. Over the past several years,
interest in lymphocyte cultures and chromosomal patterns has
led to their use in epidemiological studies of chromosome
changes in individuals exposed to benzene (35,36). Ulti-
mately, this approach may shed some light on possible
benzene-induced mutagenic effects on red blood cells (33)
and the nature of the long latent periods preceeding aplastic
anemia or leukemia in humans. The frequency of chromosomal
aberations may be clinically significant. Berlin et al.
(37) cite several instances in which others have observed an
increase in chromosome changes in leukocytes at atmospheric
benzene concentrations reportedly not exceeding 25 ppm. A
reduction of leukocyte alkaline phosphatase activity was
also observed. These sensitive parameters could serve as
valuable indices of exposure and a measure of the toxic
potential'of prolonged exposure to benzene.
NIOSH, in recognition of accumulated clinical and
epidemiological evidence to the effect that benzene is
4-14
-------
leukemogenic and a probable cause of other severe systemic
toxicity, has recommended a much more stringent standard for
occupational exposure to benzene (28). Since it is not
currently possible to establish a safe level of exposure to
a carcinogen, NIOSH recommends that exposure to benzene be
kept as low as possible. The proposed occupational standard
of a maximum of 1 ppm benzene is expected to materially
reduce the risk of benzene-induced leukemia.
Toluene (methylbenzene), xylenes (dimethylbenzenes),
and trimethylbenzenes are generally much less toxic and
volatile than benzene. Early studies attributing myelotoxic
effects to toluene have been reevaluated, and it is now
believed that the observed effects were the result of
concurrent exposure to benzene that was present as a con-
taminant. Chronic exposure studies using pure toluene has
produced evidence that it lacks the toxic potential to cause
permanent hematologic damage (38). The effects of toluene
on the central nervous system, i.e. fatigue, dizziness,
mental confusion, and anesthetic stupor, are not specific
for this compound but typify the responses to other hydro-
carbons. Absorbed toluene rapidly metabolizes to benzoic
acid, conjugated with glycine, and excretes as hippuric
acid. Thus, the efficient biotransformation mechanism and
the rate at which it is metaboloized would seem to prohibit
toluene from eliciting severe systemic effects. The thresh-
old limit value for toluene is 100 ppm. A current and
detailed review of the literature regarding the health
effects of toluene is included in the NIOSH criteria docu-
ment for occupational exposure to toluene (38).
No data are available on actual occupational or environ-
mental exposures to xylenes that warrant their consideration
as important environmental health hazards. The current
4-15
-------
xylene standard of 100 ppm was designed primarily to protect
workers against the irritating and narcotizing properties of
xylene. Toluene and xylenes were included on a recent list
of 10 substances and categories for priority testing under
the. Toxic 'Substances Control Act (39), but it appears that
these chemicals were included because of their widespread
industrial use and high rate of production rather than
because of any particular health effects. Toluene is, in
fact, a most likely substitute for benzene in many instances
and may be present in considerable quantities (8 to 16%) in
modern gasolines.
4.1.5 Additives
In addition to the numerous hydrocarbon components, a
number of additives may be present in gasoline. Generally,
concentrations of these materials are of a quantity suffi-
ciently low to preclude their significance as contributors
to the .toxicity of gasoline by inhalation.
Tetraethyl and tetramethyl lead are perhaps the most
notable gasoline additives. They are added in minute
quantities to eliminate the "knock" or detonation in the
internal-combustion engine. Lead content in gasoline varies
widely, and the use of lead as an additive has been reduced
in recent years for environmental health reasons and because
of the use of the catalytic converter. One data source
estimates that one part tetraetlhyl lead is added to 1300
parts of gasoline (40). Besides their low content in
gasolines, these lead compounds are insufficiently volatile
at ordinary temperatures to give rise to hazardous concen-
trations in gasoline vapor. (Refer to Table 3-22.)
Kehoe and others (41,42,43) investigated potential
sources of occupational exposures to gasoline containing
lead additives. They concluded that, under the prevalent
4-16
-------
environmental conditions of the occupations, exposure of
refinery workers and services station attendants to lead
alkyls was negligible.
An organic ;.halogen compound, usually ethylene dibromide
(EDB), is added'to gasolines along with the lead additives
to assist.in the removal of lead from the engine after
combustion. Of the 33 million pounds of EDB produced each
year, approximately 80 percent is used with lead gasoline
additives (44). As a component of lead additives, however,
it seems likely that EBD will be phased out of gasoline as
as result of the reduction of lead concentrations. EDB now
comprises about 25 percent of the total lead additive
mixture.* From a quantitative point of view, it would
appear that vaporization of EDB (or other halogenated ethanes)
is negligible from such dilute solutions in gasoline.
NIOSH has identified ethylene dibromide as a carcinogen
(45). This identification is based exclusively on studies
conducted with laboratory rodents; no human cancers are
known to have occurred from exposure to this substance. It
is suspected also that EDB, primarily because of its chemical
similarity to dibromochloropropane (DBCP), is mutagenic and
teratogenic and causes reproductive problems (44,46). Based
on the premise that it is not possible to establish a safe
level of exposure to a carcinogen, mutagen, or teratogen,
even very low airborne levels of EDB that may vaporize from
gasoline can may be associated with an increased risk of
adverse health effects.
4.2 GASOLINE TOXICITY STUDIES
4.2.1 Acute Intoxication
Data are limited relative to experimental or actual
human exposures through inhalation of gasoline vapors.
*
Telephone conversation with H.E. Runion, Gulf Science and
Technology Co., Pittsburgh, Pennsylvania. October 19, 1977.
4-17
-------
Inhalation of extremely high concentrations of gasoline
vapor can cause loss of consciousness, coma, and sudden
death. Several authors (17,47,48,49,50,51) have described
various1 signs and symptoms caused by severe acute gasoline
exposures. These include delirium with cyanosis, coma,
tonic and clonic convulsions, shallow and irregular respira-
tion, and variable pulse. Vomiting, inward strabismus,
contracted pupils, and loss of reflexes have also been
observed. Gasoline vapors can sensitize the myocardium to
the extent that small quantities of epinephrine may precipi-
tate ventricular fibrillation. This may explain the type of
sudden death observed in cases of accidental gasoline
exposure. Massive concentrations of gasoline vapor, on the
other hand, can lead to rapid medullary depression and death
from respiratory paralysis.
Several severe or fatal cases from inhalation of gaso-
line vapors have been reported (51,52,53). Frequently these
cases have involved brief exposures to high concentrations
of gasoline vapors in confined areas. A report by Wang and
Irons (53), for example, describes a fatal case of gasoline
intoxication. The victim was an aircraft mechanic who
entered an unpurged aircraft wing tank and was thereby
exposed for approximately 5 minutes to an estimated 5000 to
16,000 ppm of gasoline vapor. Postmortem examination
revealed acute pulmonary edema, acute exudative tracheo-
bronchitis, passive congestion of the liver and spleen, and
early acute hemorragic pancreatitis. The authors concluded
that the clinical history and pathology were in agreement
with a diagnosis of death due to hydrocarbon poisoning. The
direct cause of death was apparently respiratory arrest with
irreversible cerebral damage.
4-18
-------
Gerarde and others (50,54) point out several reports in
the clinical literature which indicate that severe central
nervous system sequelae such as convulsions or epileptiform
seizures may occur months after an inital severe acute
exposure. ' Cerebral microhemmorhages or facial postinflamma-
tory scarring have been suggested as possible etiologic
factors. More common nondisabling sequelae that may follow
acute intoxication are peripheral neuritis, impairment of
memory, numbness of the extremities, and paresthesia.
Severe nervous system sequelae occur infrequently and,
fortunately, recovery is complete in most human cases of
acute hydrocarbon intoxication. The sequelae of acute
gasoline intoxication can involve other organ systems.
MacLean (55) reported three cases of fatal aplastic anemia
following acute exposures to gasoline with a benzene content
of approximately 10 percent. Although details of these
episodes are unavailable, benzene rather than the gasoline
itself is believed to be the etiology of the disease.
Acute inhalation exposures to milder concentrations of
gasoline vapor are usually characterized by nonspecific
anesthetic or narcotic effects. Symptoms such as headache,
vertigo, blurred vision, ataxia, tinnitus, nausea, anorexia,
and muscular weakness are not uncommon. The composition of
the gasoline and the method of generating the vapor will
ultimately affect the atmospheric concentrations and the
duration of exposure necessary to elicit these responses.
Very little data are available on experimental exposures
to gasoline vapors by inhalation. Drinker et al. (56)
studied the effects of low concentrations of gasoline vapor
on human subjects over periods of 8 hours and 1 hour.
Eight-hour exposures to nonleaded vapor concentrations of
160 to 270 ppm produced conjunctival irritation in a large
4-19
-------
proportion of the subjects. A 1-hour exposure to a concen-
tration of 500 ppm of a low-boiling distillate of commercial
gasoline produced eye irritation, and the same length of
exposure to a 900-ppm concentration of this vapor elicited
\ (.
similar effects on the eyes and caused irritation of the
nose and throat. A 1-hour exposure to the same vapor at a
concentration of 2600 ppm produced dizziness in all of the
subjects.
Fieldner and coworkers (57) incidentally recorded
observations concerning the effects sustained by two human
subjects who for brief periods breathed air containing
gasoline vapor. They observed no symptoms in either of the
two subjects following 18 minutes of exposure to concentra-
tions of gasoline vapor ranging from 300 to 700 ppm.
Exposure for 14 minutes to concentrations of 2800 to 7000
ppm produced dizziness.
Davis and his coworkers (58) attempted to relate the
effects of exposure to gasoline vapor to the chemical
characteristics of the hydrocarbon mixture. They exposed
human subjects to nonleaded gasoline having the following
approximate composition:
Percent Percent Percent
Paraffins Naphthenes Aromatics
Sample A 25 30 40
Sample B 40 35 20
Sample C 30 5 65
The only significant effect observed was eye irritation
(documented by both subjective and objective responses).
Irritation became more apparent as the vapor concentration
increased from 200 to 500 to 1000 ppm, but no differences in
the irritating potential of the three gasoline samples were
4-20
-------
noted.
The limitations posed by human experimentation and the
absence of definitive physiological parameters in the
experimental design of these studies are clear. The effects
of gasoline vapor on man are summarized in~Table 4-3.
Machle (50) furnished the only data found relating
acute gasoline exposure to toxic effects on animals. He
reported that gasoline vapor exposures in excess of 10-, 000
ppm rapidly cause death in most experimental animal species.
4.2.2 Chronic Intoxication
Little evidence was found on the health effects of
exposure to low concentrations of gasoline vapor over long
periods of time. Chronic gasoline toxicity data seem to be
limited to a few reports on occupational exposures and some
cases of gasoline abuse. Definitive, well-designed epidemio-
logic studies are not available. Service station attendants,
refinery workers, and tank-truck drivers are examples of
workers who may be subjected to exposure to gasoline vapors.
The balance of this section includes a comprehensive review
of epidemiological studies related to gasoline exposure and
an evaluation of occupational exposures to gasoline vapor.
In general, the symptoms of chronic exposure to gaso-
line vapor are ill-defined. They may consist of fatique,
muscular weakness, listlessness, nausea, vomiting, abdominal
pain, and weight loss. Exposure is also known to have
neurological effects. These include confusion, ataxia,
tremor, paresthesias, neuritis, and paralysis of peripheral
and cranial nerves (59).
Cases of repeated self-induced gasoline intoxication,
generally-involving higher concentrations of gasoline vapor,
could possibly be considered chronic inhalation exposures.
Persons who regularly engage in the practice of "gasoline
4-21
-------
Table 4-3. HUMAN EXPERIENCE: EXPOSURE TO GASOLINE VAPORS
I
to
NJ
Concentration ,
ppro
5,000-16,000
10,000
3,000
2,600
2,000
1,000
1,000
1,000
900
550
500
300-700
160-270
Exposure time,
minutes
5 min
10 min
15 min
1 hr
1 hr
15 min
1 hr
30 min
1 hr
1 hr
1 hr
18 min
8 hr
Physiological/sensory effect
Lethal
Nose and throat irritation in 2 min; dizziness in 4
min; signs of intoxication in 4-10 min. Definite
intoxication
Dizziness, nausea
Dizziness
Dizziness, mucous membranes irritated and anesthesia
Drowsiness, dullness, numbiness
Dizziness, headache, nausea
Eye irritation only
Slight dizziness, irritation of eyes, nose and throat
Eye irritation
Eye irritation
No symptoms
Eye irritation
Reference
53
57
57
56
50
57
56
58
58
56
50
57
56
-------
sniffing" may experience loss of appetite and weight,
neurasthenic symptoms, muscular weakness, and cramps (60).
Abnormal EEC's and possible liver and renal damage also have
been reported to; result from this practice. Poklis and
Burkett (6TO) , in their review of gasoline abuse, point out
that the greatest hazard associated with chronic gasoline
inhalation is exposure to aromatic hydrocarbons, particularly
benzene. Chronic benzene intoxication can result in severe
irreversible systemic effects such as encephalopathy,
aplastic anemia, and leukemia. Nothing was found in the
literature relating chronic gasoline sniffing with fatal
pathologic conditions such as liver, kidney, or bone marrow
lesions.
4.3.2 A General Consideration Regarding Gasoline Vapor
Toxicity
Gasoline has been characterized as a highly complex,
widely varying mixture of hydrocarbons and chemical addi-
tives (antiknock agents, dyes, inhibitors, etc). The liter-
ature reviewed and this report have assessed the toxicity of
gasoline primarily as a function of the independent toxicities
of its individual components. Chemical constituents that
have demonstrated toxic action have been identified and
ranked according to their toxic potential. Benzene is
undoubtedly the most hazardous component in gasoline; and,
because of benzene's unique carcinogenic potential, it would
appear that the toxicity of gasoline vapor could be assessed
exclusively in terms of its benzene content.
It should also be noted, however, that benzene can have
ah additive effect with other hydrocarbons in gasoline. A
more reasonable and more realistic assessment of the toxicity
of gasoline vapor should be based on the biological impact
of the mixture as a whole. In this manner, the additive,
4-23
-------
synergistic, and/or inhibitory effects of all the hydro-
carbon components within a biological system are considered,
and a more accurate estimation of the real toxicity of
gasoline can be
-------
been initiated by the API. A more commercially representa-
tive unleaded gasoline containing 2 to 3 percent benzene by
volume is being used in this investigation. Experiments
such as these should provide valuable toxicological informa-
tion for a-more accurate assessment of the impact of chronic
gasoline vapor exposure.
4.3 EPIDEMIOLOGY AND EXPOSURE STUDIES
No definitive epidemiologic data have been published
regarding workers exposed to concentrations of gasoline
vapor for prolonged periods of time. Early literature
dealing with the effects of gasoline vapor consists mainly
of medical reports or general observations rather than
documented, comprehensive epidemiologic studies encompassing
both clinical and environmental findings.
Machle (50), for example, reports that no symptoms of
chronic gasoline intoxication were observed in more than
2300 refinery workers., "Studies" of large numbers of
filling station attendants, tank-truck drivers, and garage
mechanics yielded similar negative results; however, Machle
reports that barrel fillers, who were exposed to extremely
high concentrations of gasoline vapor, exhibited signs of
malnutrition, pallor, anorexia, nausea, nervousness, and low
hemoglobin and erythrocyte values. Spencer's study (61) of
22 persons exposed to gasoline vapors from coupon-canceling
machines is characterized by similar nonspecific descriptions
of clinical manifestations and lack of environmental data.
Gerarde (54) reports no conclusive evidence of harmful
health effects due to exposure to gasoline vapor in service
station attendants and garage workers who were repeatedly
exposed to low concentrations of gasoline vapors and briefly
exposed to higher concentrations.
4-25
-------
In a study of painters exposed to vapors.from spray
paints diluted with gasoline, Sterner (62) describes signs
and symptoms that are typical of acute exposures to gasoline
including significant decreases in hemoglobin, erythrocyte,
and blood cell volume values and increases in mean corpus-
cular hemoglobin, mean corpuscular volumn, and reticulocyte
count. The vapor was believed to have an aromatic hydro-
carbon concentration of between 300 and 800 ppm.
MacLean (55) reported an isolated case of hemolytic
anemia and myelofibrosis in an oil company employee who had
been exposed for 12 months to gasoline vapor resulting from
spills. The benzene content of the gasoline was reportedly
less than 1 percent. He also reported a case of thrombo-
cytopenic purpura in a man who had been exposed to consider-
able concentrations of gasoline vapor intermittently over a
2-year period. In this case, the benzene content could have
been as high as 10 percent.
Concern regarding benzene content in gasoline is reflect-
ed in a number of recent studies in which the potential
health hazards associated with the handling, storage, and
transport of gasoline are being investigated. The objective
of Parkinson's investigation (63) was to assess whether any
significant health hazard occurred from exposure to benzene
during normal operations at retail filling stations and bulk
loading installations. Atmospheric benzene concentrations
were monitored and compared with biological indices of
exposure. Determinations were made of benzene in the breath
^
or of phenol in the urine. Parkinson concluded that the
benzene in air concentrations measured in this study were
significantly less than the current threshold limit value
(TLV) (actually a threshold limit ceiling value of 25 ppm)
and were unlikely to pose any benzene inhalation hazard.
4-26
-------
The highest airborne benzene vapor concentration recorded at
retail sites where gasoline of normal benzene content (up to
5% v/v) was dispensed was 3.2 ppm, averaged over a 30-minute
period* Atmospheric benzene levels during bulk gasoline
loading op'erations were somewhat higher, and several in-
dividual samples exceeded 2.5 ppm. In view of the current
recommended benzene standard of 1 ppm, the benzene vapor
concentrations to which these person were exposed might be
interpreted differently today. The results of phenol
analysis on urine samples obtained from personnel at filling
stations and bulk loading installations did not indicate any
significant exposure to benzene. This study also presented
data that characterized occupational exposures to gasolines
which contained added benzene. As the benzene content of
the gasoline was increased from 10 .to 20 to 33 percent
(v/v), the atmospheric benzene concentrations rose. Changes
in total urinary phenol levels indicated that considerable
amounts of benzene are absorbed during exposure to gasolines
containing 20 or 33 percent benzene.
In Sherwood's evaluation of occupational exposure (64),
three workers directly involved with the loading of gasoline
on tank trucks were routinely exposed to what would now be
considered hazardous concentrations of benzene. The mean
benzene in air concentrations to which these workers were
exposed were 1.6, 2.5, and 20.0 ppm. Total urinary phenol
values ,of 12, 25, and 83 mg/liter correlate with the degree
of benzene exposure. Normal excretion of phenol in humans
is 5 to 10 mg/liter (65). The author noted that both breath
and urine samples taken from one worker after a weekend of
no exposure showed some evidence of long-term retention of
benzene. Data from this study are of limited value sta-
tistically because of the small number of workers involved.
4-27
-------
Pandya et al. (66) attempted to assess the occupational
exposure of pump workers at retail filling stations. In
this study, the exposure to gasoline was expressed as a
function of benzene absorption. Urine samples from 51
exposed workers vere collected at the end of a work shift
\
and assayed for phenol. The amounts of phenol excreted
averaged 40 mg/liter. Values greater than 20 mg/liter,
evident in about 88 percent of the workers tested, were
regarded as excessive and indicative of benzene exposure.
In this study, however, no quantitative determinations were
made of atmospheric benzene at the sites over the work day.
Thus, it was impossible to correlate occupational exposures
with the amount of phenol excreted.
As evidenced by a number of these studies, much atten-
tion has been focused on the amount of phenol excreted in
the urine. This index of benzene exposure is particularly
susceptible to individual variation. Metabolic differences,
nutritional status, and dietary intake can affect phenol
excretion (37,59). It should be noted that although this
measurement provides presumptive evidence of exposure to
benzene, it does not necessarily reveal anything about the
health of the individual. Phenol in the urine indicates
that the benzene being absorbed has been detoxified and
eliminated. Health effects may become evident following
chronic or massive acute exposures, when the system can no
longer effectively detoxify the compound, or occur in
particularly susceptible tissues where benzene tends to
accumulate.
AIP has conducted an epidemiological study investigating
mortality.rate among refinery workers. Results of this
study have not yet been published, but an API representative
reports that the mortality rate was not excessive in exposed
4-28
-------
populations in comparison with a control group.* Reportedly,
the survey is quite comprehensive and accurately charac-
terizes personnel exposures.
It is not yet known just how the proposed permanent
standard regarding benzene will affect occupations related
to the storage, transportation, distribution, dispensing,
and sale of gasoline. OSHA has announced that automobile
service stations and other gasoline marketing locations,
because of their "inherently complex nature," will be
excluded from coverage under the proposed standard (67).
These facilities will be covered in a separate rule-making
and most probably by a subsequent standard for benzene
exposure in gasoline marketing. In anticipation of such a
standard for worker exposure to benzene, industrial hygienists
from both government and industry are attempting to assess
occupational exposure to benzene and gasoline vapors at
retail automotive service stations.
McDermott and Vos (68) designed and conducted an
industrial hygiene study of seven Shell service stations to
find answers to these questions:
To what exposures of benzene and other hydrocarbons in
gasoline are service station attendants subjected?
What effect do vapor recovery nozzles have on exposures?
Can exposures be correlated to factors such as amount
of benzene in the liquid gasoline, volatility of tem-
perature of the gasoline, or other conveniently measured
parameters?
*
Telephone conversation with Dr. C. Holsworth, American
Petroleum Institute, Washington, D.C. October 27, 1977
4-29
-------
The following summarizes the major results of the survey and
the conclusions drawn from these results:
Results of 84 time-weighted-average (TWA) exposure
determinations on 6 or more days sampling at each
location show that benzene TWA exposures were well
below 1 ppm except for one exposure of 2.08 ppm. TWA
' exposures to total gasoline vapors were 114 ppm or
less.
Subsequent to the determination of the TWA exposures,
eight 15-minute peak exposures to benzene and total
gasoline vapors did not exceed 1.21 ppm and 100 ppm,
respectively.
One station surveyed was equipped with a balanced vapor
recovery system. Exposures at this station were below
the detectable level (0.01 ppm benzene) on 10 percent
more days than other stations. However, during remain-
ing days, exposures at three stations were less than
those at the station with vapor recovery. The degree
of reduction and magnitude of overall exposures indicate
that vapor recover systems may not dramatically reduce
exposures to attendants.
Some attendants experienced consistently higher ex-
posures than others at the same location. No correla-
tion could be established on the basis of the following
variables: benzene content, Read Vapor Pressure,
storage tank temperature, and location of auto fill
opening. Observation indicated other variables, such
as work practices and micrometerology which are not
measured, may be implicated in this individual exposure
variation.
The benzene content in liquid gasoline ranged from 0.41
to 1.74 percent by volume. When the "equivalent ben-
zene" in gasoline is considered (which reflects the mix
of grades pumped at each location), attendants pump
gasoline with a benzene content of 1.0 volume percent
or less on 65 percent of the total days.
Hartle and Young (69) of NIOSH have begun what appears
to be a comprehensive occupational assessment of benzene
exposure at retail automotive service stations. From their
preliminary report, a few important observations may be
4-30
-------
noted.
Concentrations of benzene in the air to which individuals
were occupationally exposed ranged from 0.009 to 0.782
ppm. The mean of 99 samples analyzed was 0.080 ppm.
Eight-hour, TWA concentrations of benzene averaged
< 0.072 ppm. The values from 37 different service
stations ranged from 0.015 to 0.297 ppm.
Benzene levels of the three gasoline grades, premium,
regular, and unleaded, were 1.22, 1.58, and 1.33 liquid
volume percent (LV %) respectively.
Other variables were measured that may affect individual
exposure variation, such as temperature, wind speed,
humidity, barometric pressure, nozzle time, and amount
of fuel pumped.
On the basis of these preliminary findings, it does not
appear that service station attendants are exposed to
hazardous concentrations of benzene vapor.
A paper by Phillips and Jones (70) concerns an investi-
gation of gasoline vapor exposure to Shell employees during
the bulk loading of gasoline tank trucks. The primary
objective of this study was to determine hydrocarbon vapor
concentrations in the employees' breathing zone at various
facilities and compare these exposures to toxicological
standards (legal or other) for gasoline and/or its com-
ponents. The investigation revealed no exposures that
threatened employee health or safety, based on available
information on the toxicity of gasoline. Although experi-
mental data are specific for the five facilities sampled,
the authors made the following general conclusions:
Gasoline exposures to driver-salesmen and full-time
loaders at loading racks are not expected to pose a
health hazard or cause a violation of current Federal
or state Occupational Safety and Health Standards.
Proper supervision and maintenance are important in
4-31
-------
controlling leaks, spills, and improper loading proce-
dures, which contribute to employee exposures.
It should also be noted that the calculated TLV used to
estimate safe levels of exposure in this study are based on
the; current benzene criteria of 10 ppm. These data should
be reevaluated on the basis of the proposed 1 ppm benzene
standard to obtain an accurate assessment of occupational
gasoline exposure associated with bulk loading facilities.
OSHA has no Federal standard for occupational exposure
to gasoline vapor, although separate limits are established
for 14 individual hydrocarbon constituents and some additives.
McDermott and Killiany (71) identified the major hydrocarbon
components in gasoline vapor and, using these data, calculated
a TLV for a gasoline mixture. Based on the toxicity of
hydrocarbon compounds in gasoline vapor, a 300-ppm, time-
weighted average exposure over an 8-hour period was estimated
to be a reasonable limit along with a 1000 ppm peak over 15
minutes. The authors included benzene in the ACGIH "TLV for
mixtures" equation [Appendix C of the 1974 TLV booklet (72)]
as having an additive effect with other hydrocarbons at its
current TLV level of 10 ppm.
In view of NIOSH's recent recommendation that per-
missible occupational exposure limits for benzene be reduced
from from 10 to 1 ppm, Runion (74) reexamined the practical
impact of such a standard in relation to gasoline exposure.
Gasoline TLV's were calculated using the ACGIH method and
incorporating the present benzene TLV criterion of 10 ppm,
as well as the proposed criterion of 1 ppm. The criteria
used for the other major gasoline compounds were actual or
estimated'ACGIH TLV values. Figure 4-1 reflects the results
of these calculations. The consequence of a lowered benzene
limit on a gasoline TLV is apparent. Gasoline containing 1
4-32
-------
0 24 6 8 10 12 14
PERCENT BENZENE IN GASOLINE - LIQUID PHASE
Figure 4-1. Calculated gasoline threshold limit value,
reflecting impact of present vs. proposed benzene
TLV standard as a function of the liquid
volume percent benzene in the gasoline.
4-33
-------
LV percent benzene, for example, now has a TLV of 300 ppm,
whereas the same gasoline, under the proposed benzene
standard, would have a TLV of less than 150 ppm.
4-34
-------
REFERENCES TO SECTION 4
Criteria for a Recommended Standard...Occupational
Exposure to Alkanes (C5-C8). DHEW (NIOSH) Pub. No.
77-151. National Institute for Occupational Safety and
Health. Cincinnati, Ohio. March 1977.
Yamada, S. Polyneuritis in Workers Exposed to N-
hexane, Its Cause and Symptoms. Jpn. J. Ind. Health,
9:651-59, 1972. [cited in (1)]
Inoue, T., et al. Industrial Health Survey of High
Incidence of N-hexane Intoxication among Vinyl Sandal
Manufacturers. Jpn. J. Ind. Health, 12:73-84, 1970.
[cited in (1)]
Gaultier, M., G. Rancurel, C. Piva, and M. L. Efthymioc.
Polyneuritis and Aliphatic Hydrocarbons. J. Eur.
Toxicol., 6:294-96, 1973. [cited (1)]
Herskowitz, A., N. Ishii, and H. Schaumburg. N-hexane
Neuropathy - A Syndrome Occurring as a Result of Indus-
trial Exposure. N. Engl. J. Med., 285:82-85, 1971.
[cited in (1)]
Yoshida, T., et al. An Electrophysiological Study on
N-hexane Polyneuropathy. Clin. Neurol. (Tokyo),
14:454-61, 1974. [cited in (1)]
Yamamura, Y. N-hexane Polyneuropathy. Folia Psychiatr.
Neurol. Jpn., 23:45-57, 1969. [cited in (1)]
Patty, F. A., and W. P. Yant. Report of Investigations
Odor Intensity and Symptoms Produced by Commercial
Propane, Butane, Pentane, Hexane, and Heptane Vapor,
No. 2979. U.S. Dept. of Commerce, Bureau of Mines,
1929. [cited in (1)]
Fuhner, H. The Narcotic Effect of Gasoline and Its
Components - Pentane, Hexane, Heptane, Octane. Biochem.
Z., 115:235-61, 1921. [cited in (1)]
4-35
-------
10. Truhaut, R., et al. Preliminary Electrophysiologic
Results Following Experimental Poisoning with Technical
Hexane and Heptane in White Rats. Arch. Mai. Prof.
Med. Trav. Secur. Soc., 34;417-26, 1973. [cited in
(1)]
11. Swann, H..E., B. K. Kwon, G. K. Hogan, and W. M. Snellings.
1 Acute Inhalation Toxicology of Volatile Hydrocarbons.
Amer. Ind. Hyg. Assoc. J., 35:511-18, 1974. [cited in
(1)]
12. Lazarew, N. W. On the Toxicity of Various Hydrocarbon
Vapors. Arch. Exp. Pathol. Pharmakol., 143:223-33,
1929. [cited in (1)]
13. Miyagaki, H. Electrophysiological Studies on the
Peripheral Neurotoxicity of N-hexane. Jpn. J. Ind.
Health, 9:660-71, 1967. [cited in (1)]
14. Tsobkallo, G. I. The Influence of Certain Hydrocarbons
Included in the Composition of Gasoline on the Respira-
tion and Blood Pressure. Farmakol. Toksikol., 10:23-
30, 1947. [cited in (1)]
15. Gerarde, H. W. The Alicyclic Hydrocarbons. In:
Industrial Hygiene and Toxicology, 2nd edition, Vol.
II. F. A. Patty (ed.) Interscience Publishers, New
York, 1963. pp. 1207-1217.
16. Criteria for a Recommended Standard...Occupational
Exposure to Benzene. DHEW (NIOSH) Pub. no. 74-137.
National Institute for Occupational Safety and Health.
Cincinnati, Ohio. 1974.
17. Cornish, H. H. Solvents and Vapors. In: Toxicology.
The Basic Science of Poisons. L. J. Casarett and J.
Doull (eds.). MacMillan Publishing Co., Inc., New
York, 1975. pp. 503-526.
18. Hardy, H. L.,and H. B. Elkins. Medical Aspects of
Maximum Allowable Concentrations - Benzene. J. Ind.
Hyg. Toxicol., 30:196-200, 1948. [cited in (16, 17)]
19. Wilson, R. Benzene Poisoning in Industry. J. Lab.
Clin: Med., 27:1517-21, 1942. [cited in (17)]
20. Pagnoto, L. S., et al. Industrial Benzene Exposure
from Petroleum Naphtha - I. Rubber coating industry.
Am. Ind. Hyg. Assoc. J., 22:417-21, 1961. [cited in
(16)]
4-36
-------
21. Deichmann, W. B., W. E. MacDonald, and E. Bernal. The
Hemopoietic Tissue Toxicity of Benzene Vapors. Toxicol
Appl. Pharmacol., 5:201-24, 1963. [cited in (16)]
22. Nau, C. A., J. Neal, and M. Thornton. C9-C12 Fractions
Obtained from Petroleum Distillates - An Evaluation of
Their.Potential Toxicity. Arch. Environ. Health.,
' 12:382-93, 1966.
23. Wolf, M. A., V. K. Rowe, S. S. McCallister, R. D.
Hollingsworth, and F. Oyen. Toxicological Studies of
Certain Alkylated Benzenes and Benzene - Experiments in
Laboratory Animals. Arch. Ind. Health, 14:387-98,
1956. [cited in (16)]
24. Aksoy, M., K. Sincol, S. Erdem, and G. Sincol. The
Hematologic Effects of Chronic Benzene Poisoning in 217
Workers. Br. J. Ind. Med., 28:296-302, 1971. [cited
in (17)]
25. Erf, L. A., and C. P. Rhoads. The Hematological Effects
of Benzene (Benzol) Poisoning. J. Ind. Hyg. Toxicol.,
21*431-35, 1939. [cited in (16)]
26. Greenberg, L., M. R. Mayers, L. J. Goldwater, and A.
Smith. Benzene (Benzol) Poisoning in the Rotogravure
Printing Industry in New York City. J. Ind. Hyg.
Toxicol., 21:395-420, 1939. [cited in (16, 17)]
27. Delore, P. and C. Borgamano. Leuce'miaigue au cours de
I1 Intoxication Benze"nique. J. Med. Lyon. , 9:227-33,
1928. [cited in (29)]
28. Revised Recommendation for an Occupational Exposure
Standard for Benzene. National Institute for Occupa-
tional Safety and Health. Cincinnati, Ohio. August,
1976.
29. Infante, P. F., J. K. Wagoner, R. A. Rinsky, and R. J.
Young. Leukemia in Benzene Workers. Lancet, 2:76-78,
1977.
30. Vigliani, E. C. Leukemia Associated with Benzene
Exposure. Ann. N.Y. Acad. Sci., 271:143-51, 1976.
[cited in (28)]
31. Aksoy, M., S. Erdem, and G. Sincol. Leukemia in Shoe-
workers Exposed Chronically to Benzene. Blood, 44:837-
41, 1974. [cited in (28)]
4-37
-------
32. Tareeff, E. M., N. M. KontchalovsKaya, and L. A. Zorina.
Benzene leukemias. Acta Unio. Int. Contra. Cancrum,
19:751-55, 1963. [cited in (28)]
33. Vigliani, E. C. and G. Saita. Benzene and leukemia.
New Engl. J. Med., 217:872, 1964. [cited in (16, 34)]
34.. Hamilton, A. and H. L. Hardy. Aromatic Hydrocarbons.
In: Industrial Toxicology, 3rd edition. Publishing
Sciences Group, Inc., Acton, Mass. 1974. pp. 271-276.
35. Forni, A. M., A. Cappellini, E. Pacifico, and E. C.
Vigiliani. Chromosome Changes and Their Evolution in
Subjects with Past Exposure to Benzene. Arch. Environ.
Hlth., 23:385-391, 1971. [cited in (34)]
36. Tough, I. M. Chromosome Aberrations and Exposure to
Ambient Benzene. Lancet, 1:684, 1965. [cited in (34)]
37. Berlin, M., J. Gage, and E. Jonnson. Increased Aromatics
in Motor Fuels: A Review of the Environmental and
Health Effects. Work-Environm.-Hlth., 11:1-20, 1974.
38. Criteria for a Recommended Standard...Occupational
Exposure to Toluene. HSM 73-11023. National Institute
for Occupational Safety and Health. Cincinnati, Ohio.
1973.
39. Anonymous. Interagency Committee Recommends Ten Sub-
stances, Categories for Testing. Chemical Regulation
Reporter, 1 (30):1025-26, 1977.
40. Hamilton, A. and H. L. Hardy. Lead. In: Industrial
Toxicology, 3rd edition, Publishing Sciences Group,
Inc. Acton, Mass., 1974. pp. 85-121.
41. Kehoe, R. A. Industrial Lead Poisoning. In: Indus-
trial Hygiene and Toxicology, 2nd edition, Vol II. F.
A. Patty (ed.). Interscience Publishers, New York,
1963. pp. 941-985.
42. Kehoe, R. A., J. Cholak, J. A. Spence, and W. Hancock.
Potential Hazard of Exposure to Lead I. Handling and
Use of Gasoline Containing Tetramethyllead. Arch.
Environ. Hlth., 6:239-54, 1963. [cited in (48)]
43. Kehoe, R. A., J. Cholak, J. G. Mcllhinney, G. A.
Lofquist, and T. D. Sterling. Potential Hazard of
4-38
-------
Exposure to Lead II. Further Investigations in the
Preparation, Handling and Use of Gasoline Containing
Tetramethyllead. Arch. Environ. Hlth., 6:255-72, 1963.
[cited in (48)]
44. Anonymous. "EPA to Study EDB in Response to Petition;
EDF Calls fbr Regulation under Toxic Act. Air/Water
i Pollution Report, 15 (36):356, 1977.
45. Suspected Carcinogins, 2nd edition. A subfile of the
Registry of Toxic Effects of Chemical Substances.
Ethane, 1, 2-dibromo-. KH92750. National Institute
for Occupational Safety and Health, Cincinnati, Ohio,
1976. p. 105.
46. Anonymous. Ethylene dibromide. Manufacturers of EDB
to Cooperate in Animal Studies; Dow Seeks Human Data.
Chemical Regulation Reporter, 1 (27):895, 1977.
47. Hamilton, A. and H. L. Hardy. Aliphatic Hydrocarbons.
In: Industrial Toxicology, 3rd edition. Publishing
Sciences Group, Inc., Acton, Mass., 1974. pp. 263-69.
48. American Petroleum Institute. API Toxicological Review
of Gasoline, First Edition. New York, 1967.
49. Von Oettingen, W. F. Poisoning, 2nd edition. W. B.
Saundus Co., Philadelphia, 1958. [cited in (48)]
50. Machle, W. Gasoline Intoxication. J.A.M.A., 117:1965-
71, 1941.
51. Browning, E. Toxicity of Industrial Organic Solvents,
Medical Research Council Report 80. Her Majesty's
Stationery Office, London, 1953. [cited in (48)]
52. Ainsworth, R. W. Petrol-vapor poisoning. Brit. Med.
J., 1:1547-48, 1960. [cited in (48)]
53. Wang, C. C. and G. V. Irons. Acute Gasoline Intoxi-
cation. Arch. Environ. Hlth., 2:114-16, 1961.
54. Gerarde, H. W. The Aliphatic (Open Chain, Acyclic
Hydrocarbons. In: Industrial Hygiene and Toxicology,
2nd edition, Vol II. F. A. Patty (ed.). Interscience
Publishers, New York, 1963. pp. 1195-1205.
55. MacLean, J. A. Blood Dyscrasia after Contact with
Petrol Containing Benzol. Med. J. Australia, 47:845-
49, 1960. [cited in (48)]
4-39
-------
56. Drinker, P., C. P. Yaglou, and M. F. Warren. The
Threshold Toxicology of Gasoline Vapor. J. Ind. Hyg.
Toxicol., 25:225-32, 1943. [cited in (48, 58)]
57. Fieldner, A. C., S. H. Katz, and S. P. Kinney. Per-
meation of 'Oxygen Breathing Apparatus by Gases and
Vapors, Technical Paper 272, U.S. Bureau of Mines,
i 1921. [cited in (58)]
58. Davis, A., L. J. Schafer, and Z. G. Bell. The Effects
on Human Volunteers of Exposure to Air Containing
Gasoline Vapor. Arch. Environ. Hlth., 1:548-64, 1960.
59. Swinyard, E. A. Noxious Gases and Vapors. In: The
Pharmacological Basis of Therapeutics, 4th edition. L.
S. Goodman and A. Gilman (eds.). MacMillan Company,
Toronto, 1970. pp. 930-43.
60. Poklis, A. and C. D. Burkett. Gasoline Sniffing: A
Review. Clin. Toxicol., 11:35-41, 1977.
61. Spencer, 0. M. The Effect of Gasoline Fumes on Dis-
pensary Attendance and Output in a Group of Workers.
Pub. Hlth. Rep., 37:2291, 1922. [cited in (50)]
62. Sterner, J. H. Study of Hazards in Spray Painting with
Gasoline as Diluent. J. Ind. Hyg. Toxicol., 23:437-47,
1941. [cited in (48)]
63. Parkinson, G. S. Benzene in Motor Gasoline - An Inves-
tigation into Possible Health Hazards in and around
Filling Stations and in Normal Transport Pperations.
Am. Occup. Hyg., 14:145-53, 1971.
64. Sherwood, R. J. Evaluation of Exposure to Benzene
Vapor during the Loading of Petrol. Brit. J. Ind.
Med., 29:65-69, 1972.
65. Porteous, J. W. and R. T. Williams. Studies in Detoxi-
cation. 20. The Metabalism of Benzene. II. The
Isolation of Phenol, Catechol, Quinol, and Hydroxyquinol
from the Ethereal Sulfate Fraction of the Urine of
Rabbits Receiving Borally. OBiochem. J. 44:56-61,
1949. [cited in (66)]
66. Pandya, K. P., G. S. Rao, A. Shasmana, and S. H. Zaidi.
Occupational Exposure of Petrol Pump Workers. Am.
Occup. Hlth., 18:363-64, 1975.
4-40
-------
5.0 "GASOLINE VAPOR CONTROL TECHNOLOGY
\ ..
5.1 REDUCTION OF TOXIC COMPONENTS VERSUS TOTAL HYDROCARBONS
IN GASOLINE
In this section, vapor control techniques are evaluated
to determine the effectiveness of the control of the more
toxic componets relative to total hydrocarbon removal effici-
ency.
In transport operations, the hydrocarbon concentration
of the vapors during gasoline loading is usually 30 to 50
percent by volume (1). Table 5-1 presents typical analyses
of hydrocarbon fractions, along with the boiling point of
each component.
Table 5-2 lists toxic constituents with the threshold
limit values and boiling points of each component.
The efficiency of the control of toxic components is
expected to be greater than that of overall vapor removal.
This is discussed qualitatively for each control option in
light of its operating principles and the data given in
Tables 5-1 and 5-2.
5.1.1 Thermal Incineration
Well-designed and properly operated thermal inciner-
ators should achieve equally high removal of all hydrocarbon
species above C^; the C$, C^, C2, and C^ compounds are more
difficult to incinerate.* The more toxic components shown
in Table 5-2 are, however, high-molecular-weight (Cfi or
greater) molecules, which will tend to oxidize more readily
than the larger fraction of hydrocarbons (propane, N-butane,
isobutane). Catalytic and direct-flame incinerators designed
*
Telephone conversation between D.M. Augenstein, PEDCo
Environmental, Inc., and Mr. Crowd, Air Resources, Inc.,
Palatine, Illinois, on September 28, 1977.
5-1
-------
Table 5-1. ANALYSES OF HYDROCARBON FRACTIONS OF
GASOLINE LOADING VAPORS AND RELATIVE VOLATILITY
Percent by volume (% v) Relative volatility,
Deckert(l)a Shell(2)b Amoco(3)c boiling point, °C(4)
i°
Propane
Isobutane
Butene
N-butane
Isopentane
Pentene
N-pentane
Hexane
Reported by source to be typical hydrocarbon composition (1).
Other hydrocarbons comprise 22.2 % v.
c Ranges due to seasonal and operational variations.
1.4
6.9
7.6
41.5
18.4
12.2
4.8
7.2
0.8
5.3
1.0
38.0
22.9
1.2
7.0
1.5
3.8-4.2
12.2-24.2
0.5-1.8
21.4-36.8
16.0-24.7
0.3-0.9
4.1-5.8
0.2-0.8
-42.1
-11.7
-6.9
-0.5
27.9
37.0
36.1
68.7
5-2
-------
Table 5-2. THRESHOLD LIMIT VALUES, RELATIVE VOLATILITY, AND
CONCENTRATIONS OF SELECTED TOXIC VAPORS FROM GASOLINE
I. LOADING OPERATIONS
Component3
Benzene
1,3,5 trimethylbenzene
1,2,4 trimethylbenzene
1,2,3 trimethylbenzene
Isopropylbenzene
Ethylbenzene
Xylene (P,M,0)
Toluene
Cyclohexane
Cyclohexene
Other benzene
compounds
TLV,(5) Boiling pt.,(4) Concentration, ppnr
ppm
1.0
25
25
25
50
100
100
100
300
300
°C
78.1
165
170
176
152
136
138-144
111
81
83
>180
Shell(2)
Amoco(3)
500-4400
100-300
100-600
100-400
100-300
200-600
1000-2400
5700-11000 18000
900-1200 NRd
100 NR
100-900 NR
7000 ave.
13000 max.
5000
Selected on the basis of toxicity, volatility, and concentration.
Composition of hydrocarbon fraction only; does not include
inorganic constituents such as air.
c Average vapor composition of 0.7 v % corresponds to a mean
benzene gasoline content of 1.0 wt. %. The maximum vapor
composition of 1.3 v % corresponds to a gasoline benzene content
'of 3.5 wt. %.
NR - not. reported.
5-3
-------
to achieve 95 percent total hydrocarbon destruction should
obtain a higher efficiency on toxic components such as
benzene, toluene, and xylene. Test data are apparently not
available on inlet and outlet gas compositions for this
application.
5.112 Carbon Adsorption
Initially and for a limited period, multicomponent
hydrocarbon vapors are adsorbed equally well. As the carbon
bed retains more and more components of lower volatility
(higher boiling points), the highly volatile (lower boiling
points) components revaporize. The point at which the
adsorption of the more volatile component begins to decrease
is called a breakpoint. This continues as the next lower
component displaces the higher one, until the exit vapor has
reached the desired maximum concentration, at which time
another carbon bed is placed on stream while the other is
regenerated.
As shown in Tables 5-1 and 5-2, toxic components are
the least volatile of all major hydrocarbon constituents.
In an adsorption system designed to reduce hydrocarbons by
95 percent just before bed regeneration, the exit gases
would consist mainly of propanes and butanes with little or
no toxic potential.
No test data were found on outlet gas composition for
this application.
5.1.3 Absorption
According to a major equipment manufacturer, the
absorption of multicomponent organic vapors will generally
be selective according to respective volatilities.* The
rate of absorption of highly volatile components such as
butane and propane will be less than that for low-volatile
components such as benzene and toluene; therefore, a high-
*
Telephone conversation between D.M. Augenstein, PEDCo Envir-
onmental, Inc., and Mr. Robert Chironora, Croll-Reynolds Co.,
Inc., Westfield, New Jersey, on September 28, 1977.
5-4
-------
pressure gasoline/gasoline vapor absorption system achieving
95 percent removal of total hydrocarbons should attain
higher efficiency for the toxic components. Data on gas-
liquid phase equilibria of the specific components in the
system are needed to make a quantitative prediction of the
theoretical absorbtion rates of each component. Data are
not readily available on inlet and outlet gas composition
for this application.
5.1.4 Condensation
When high-pressure cooling is used to condense part of
the hydrocarbon vapors, the toxic components will condense
more readily than the lighter hydrocarbons. This, again, is
due to the higher boiling points of the toxic components.
Also, a condenser achieving 80 percent total hydrocarbon
reduction by condensation should attain much greater removal
of the toxic constituents; however no data are available to
substantiate this assumption.
5-5
-------
REFERENCES TO SECTION 5
1. Deckert, W.H. Control of Vapors from Bulk Gasoline
Loading. J APCA 8:223-33. 1958: Cited in Danielson,
J.A. Air Pollution Control Engineering Manual. AP-40.
1973 p 655.
2. McDermott, H.J., and S.E. Killiany, Jr. Quest for a
Gasoline TLV. Presented at the 1976 American Indus-
trial Hygiene Convention, Atlanta, Ga. May 12-16,
1976.
3. Walker, D.C., H.W. Husa, and I. Ginsburgh. Demon-
stration of Reduced Hydrocarbon Emissions from Gasoline
Loading Terminals. Amoco Oil Co. for U.S. Environ-
mental Protection Agency. Washington, D.C. Contract
No. 68-02-1314. EPA-650/2-75-042. June 1975.
4. Handbook of Chemistry and Physics. 48th Edition. R.C.
Weast (ed.) The Chemical Rubber Co. Cleveland, Ohio.
1968. p C-75.
5. Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment with
Intended Changes for 1973. American Conference of
Governmental Industrial Hygienists. 1973.
5-6
-------
APPENDIX A
GASOLINE LOADING TERMINAL VAPOR EMISSIONS
The following gasoline stocks were loaded at the terminal during the
four seasonal . test periods:
Table A-l
Reid Vapor Pressures
.'id Vapor ^essure, psi
Stock Fall Winter Spring Summer
T.endec! Hep.ular 11.5-12.2 13.4 12.2 10.4
Unlendcd Regular 12.5-12.8 13.3 11.4 9.1
Premium 12.4 13.4 13.1 10.4
The gasoline vapor content of the mixed feed gas to the oxidizer
during the test periods is shown below:
Table A-2
Gasoline Vapor Concentration
Test Period % Saturation Ambient Temperature, °C
Normal Terminal Operation
Fall
Winter
Spring
Summer
Ton-Loaded Trucks
Fall .
Winter
Spring
Summer
Bottom-Loaded Trucks
Fall
Winter
Spring
Summer
(Top-Loaded and
78
67
60
93
100
100
89
94
75
--
73
79
Bottom-Loaded Tracks')
4.8
4.6
17.2
15.0
7.2
-7.8
13.4
21.7
4.5 '
10.0
23.9
A-l
-------
Table A-3 .
An.ily«:I« of Ai r-l'.ipor .Fr-rd t<> oxi
rprponent Volur
Fa 1 1
rest 5
b^e- Lo.TcJini;
tor
N> .
1
1
3
6
5
6
7
8
9 .
10
11
12
11
1_
15
16
17
IP
15
20
21
22
23
24
25
26
27
28
29
30
11
12
11
34
15
Hvdr.ic ir'"l."n fo~ p.Ticnc
Me t!:nno
Ethjni-
F.tli.inc: Rtliylc-nt-
Mcth.ir.r: Fth.-ino; Erhylene
Prnpvlcni'
Propani'
Itcn 5 » H.T-, 6
I «ohu tarn.-
Isobutyleno -* 1; Rutone
N-But.iru'
r-2-Butcne
lun If- * Item I 1
C-2-Bntene
1-Me-l-Butc-n-.
[sppuncane
1-Pentene
2-Me-l-li'itcm-
2-.Vc.--l, 1-Hun-J. . ii>
N-Pentane
T-2-Pentcnc
Item 19 + Item 20
C-2-Pentcne
2-Me-2-Bntcnc
2, 2-Pinethvl butane
Cyc lonentonr
3-Mn- 1 -Pent cm- ; 4-Jic - 1-Pi n:enc-
4-Me-C-2-Pentcno
2,1-i'iirnothy 1- l-Putenr
It-rn 27 ' Iten 28
4-Ve-C-.'- Peni ; .'-"- 1 , ' Pent.Tl ion"
Cyt lopenl.inc
4-Mc-r-2-Pt-ntcnc
2.3 Dimothvlhutane
If-. 1.' + I: cm 1 !
2-M^-r, ntar-
1 i nc- ncr
" 1) "1
,
0.59
0.
'»'!. I?'
1.
0.27 14
1 .
0.').', 16
i
1.
0.
IT
0.
0.
5
n.
n.
1.
rt t
.
ii.
'.
IP.
'i.
'
L .
tvii
i
78
^6
69
.52
|i
. 19
77
17
23
.79
50
84
78
95
59
34
24 '
14
1 l>i
02
01
15
06
5H
r-1
top
'12
2.R6
0.46
3.77
14.72
1.06
36.81
1.67
1.04
0.21
17.65
0.16
0.77
0. o 1
5.60
0.85
0.52
1.21
0.21
0.1 )
U.l/'
0.02
0.04
".11
0.05
0.55
I. -
hot.
*]0
2.12.
0.29
3.64
15.12
1.12
34.9n
2.07
1.40
0.26
1S.')S
0.55
0.92
6.i7
0.66
1.44
0.23
0. !1
' '. "
0.02
0 . 0.'i
U.31
0.06
0.6|
1
Vint,T Tcsf. ^P
" i n
To
.-r.; _ - :--. r ( -
hist-- l.p.idir;-, Si-r- l.o.Tlin^ '-.T~n- . ',"'.-
lino norn.T I
:.- 17 .! \t.
0.2'i 1.71
9V. 'I7 ..''
21. 1H 19. -.2
1.65
0.11 28.6'.
2.1"'
1."
') . 3 '-
19.1!
0.61
1.-10
4 . 1 S
0.94
O.66
1.4'.
i:. !.'.
o ! i
t '
||. .17
'I. "
i: i ",
'". 5'!
K
CP[> hot . 1 i".c rinr- 1 1
« 14 « 1 R It -' 1
1.
il.
1.27 4.17 n. Jo
7.6R '-.I7 '"-."6 t
21.44 0.1| 17.55 21
1.70 l.'iS I.
29.1.'- O.P. 29
2.1- I.
) 1 . 4
1.6, 1.5? k
U.29 0.11 .'0.
16."2 19. I. 21
0.53 0.56 0.
O.SR 0.9'. 0.
4 . .' '.
(/.S)
5. -'4 6.
0.57 0 . fi 2 0 .
1 . M 1 . 3,« 1 .
O.J6 '\15 M.
P.:l ".I-' '-.
. . » .
n.
0.
0 . O/", ii . O6
1, I,. ''I 0.
II. Ill (I.I.'. M.
'i.'.l (..'.'» 0.
.''" .'' "
12
57
.'.7
.0-
7',
.63
ST
,
2S
27
.1 1
5.'.
RR
."5
6r.
''
.M
l'<
i|O
02
a'.
17
Ii5
.M
»*i
c
,^
0.
1.
27
1 .
25
2.
1.
0.
19
0.
1.
*>.
0.
II.
1.
1).
1) t
ri
n.
o.
".
o.
".
o
p
' '.
-.,
56
68
. |7
79
. !7
6K
94
36
. 77
65
11
":
9'.
72
72
19
!7
I i
05
"."
T'-
ii'-,
""'
h"t. :p-. :. lir.-.- T.T-.ll C'.">. VT.
f' > ; <-. -.-;c :.-_ i . -
i . : ' fi. '.' .21 '. -r '-.:'.
".11
'..)( n.n '.-= -.1- -.
- .- .- -
,.. i '
- . »' . - '
2'.. 1" .". . .' ' < . '= '.''.<<- !.'. T3 !- . -7
! . -c 1 .-'. ! 1 . V- "'. " - ! ."
2 "* 1 2 .' 7 2 " ' - ' 2 ' . 2 5 2 7 . ^ ' ' . ' '
2. '.' .\ - ! -'.' " '.: .'. ' '
1.7? .-.;< ' n.'.
' . 1 1 ':.V, . '- '). '
7n. 01. .'| . ' '- ".."" 24. 7 .'!.""
o..-.; ".~\ ,-- o;: -..-- ;
l.'-5 I.--9 '.-" ''.- .'
'-." .'
. '> 1 '. . ' '.
l.'ll ll.O-
1 -. c. !-. <" 9.0]
O.7n f.7? .'iH '-.I7 ".!
1 .6-, 1 . -,2 1 ! ' '\7! 1 . -'.
0.1'. 0.1'. > ' . l| 11. 51 o. ;-
P. J6 -. ! '. . ' ' ".'':> . !
/> 1 /. O.'. - 1 ' . r '.
11.':'
CI.05 .O.07 '."^ O."2 "." =
' ' . '. ' '.'
O. l'i '1. .'' " ' - ' ' '"
ll.-'i ' .' ; -.'"'.
:.-.. n. ', . .' t . ' .~!
.
..'. . - ."- . " -!.*
-------
Table A-3 (Continued).
.-n.j Iv ^ i .; "i .'-. i r-".irv-r r ! * "
L .T !
basi- .
! -.
1 ir.c nor-j I
uv:!r.ic.ir'-'-r f^-r. --.c-n:
!-Me-l-Pentrne
l-Me-Pcntann : '-Hexene; 2-FthvI -1 -".ntcno
-3-Hexene
'-3-Hexene
tern 38 + Item 19
l-Me-Cvc lopcntcne
!-Me-2-Pentpne
tern 41 4- I tern 42
-Me-T-2-?enterv
i i i
P.
1
0
0
n
r,
n
,09
.12
.04
05
.07
. 1 "
- ~ ">
n.!.i- :
top hc=-
- 1 2 " ! !
n.08 0.09
I .0."^ r.i''-; 1.05 o.!2
(1. Oft | .11 1.1 : "- 1*7 ! . 71
o.r.i n.'U
O.n", n.0">
n.ns 1.17 0.15 '..i .'
0.0
Iter- 51 4- Item 43 "" "-7n n-^ °-^
Icem'.74-Item4841tem49 ' . - ' I . ). 1 . -
3-HC-C-2 Pentene 0.10 o.io 'o.lO 1.00 0.08 0.09 O. n o.d" ".in '. : O.oi O.n
i^-Dincthyl-T-2-Pentrne ' "-"I n-01 °-02 ' ° f" .
'tern 54 + Item 55 ,..''"
Me-Cy<.iopent,Tne; 3,3-Dtmethy 1-1-Pentone ".49 0.51 0.49 O.V, ".!." '.M 'i.5'- O.i-; 0.3! n.-,o
2,2-Dimethylpentane 0.°5
' .2,2-Dir.,ethyIpentane; 2,3-nimethvl-2-But^ne :, 0.05 0.09 O.rV. n.r>5 0.04 0.0'- O.o.'. 1.1,
2,3,3-Trimethyl-l-Butene O -i n i' O 7«
2"nD?Lthj!pen"ne 0.1? 0.13 0.13 0.10 o.IO 0.10 o.,, n.n, O.H n.o- r-! m oiw oili
1 . 2,4-Mimethy 1-2-Pentene ; 3-Kthy I - 1 -Pent err*;.
3-Me-l-Hexene ""
i Benzene 0.15 0.21 0.05 P.-H7 c.K, 0.1" ".^17 ". ^ n.-- n.--
2,i, j-Trimethylbutane n-''2 . r , ,
2.4-Dimethyl-l-Pentene 0.03 0,05 mr 0.0', .0.05 r.. , n.nr, o.I-
Item 64 4- Item 65 °-'"' "''
Item 63 4- I ten 64 °-'7 p, ,. , ,
Item 64 + 4,4-Oimethyl-C-2-Pentcne 0.02 P.O.1 O.O/, n.'l ' - '-
nt
-------
Table A-3 (Continued).
1 ten
No.
69
70
71
72
. 71!
74
175]
76
77
78
79
80
81
C. -
84
85
86
87
88
f89j
90
91
92
91
94
95
%
97
98
99
100
bjit.1-
1 i no
Mv.lroc ,r<- -n r --'I 1
1-Me-Cyc lopentene
Item 69 + 2-He-C- 3-Hexcnc
Item 69 4- 2 ,4-nincthy 1-2- Pentene
Item 70 4- 2,4-Dlmerhvl-2-?entone
2 ,4- Dimethyl -2- Pent c-ne ; 1-El ;iv 1 - 1 - PP. n tone ;'
3-Me-l-llexenc
2, 3 -Hi me thy 1-1-Pentcnr : 2-;!e-T-3-Hexene
fltem 74 4 5-Me-l-tleyene ; T- ) , j-nimetliyl-'-
Tyc lopentene ; C-3 ,')- Dine thycyc lopentene
3, 1-1)1 met hv 1 pent a ne
(.'yc 1 ohcxane
Cyc lohexane ; i-Me-C.-.'-llexeri
2-Me-Hexane ; 5-Me-C-2-Hexene
1 , 1- Dime thy Icyc lopent-nne
Item 70 i T : -.
',..,...'...'." ..
Cyclolicx*,,,
2-Me-llexane; 1 , 1- Dime thy Icyc lopentane
2, 1-Dimethy Ipentane
Item 86 4 3,6-Uimethy l-C-2-Pentene
3-M3-llcxanc
' I -C-3- Dime thy Icyc lopcnt.ine ; I-Ve-l-Mcxenc ; *
3,4-niraethy 1 -T-2-~cntene
1 -T- 3- Dime thy Icyc lopentane
Item 90 4 l-lleptene; 2-Ethyl-l-Pcntene
3-Ethyle Pentane; 1-Me-T-2-llexene
I -T-2-nlmcthylcyc lopentane
Item 92 4 Item 93
2,2,4-Tr imethy Ipentnnf
Item 95 + T-3-lleptene
Item 93 4 3-Ethy 1 pentane
C-3-||eptene; 1 ,4-Oine thy Icvc lopentene
3-Mc-C-l-IU'xcne ; 2-Me-2-Mf.xene
It 99 * 1-Hc-T- 1-llcxi-ne
Ana [vsis ci 'ir-..ipor ."-i.-«.-, i " :
Mil [cir- -i icor : .-.-.:
l.o.idin-: h,T'.<.'- Ir.n.lin-
nr^r~j 1 ton boc . I i ~c- nor il t.v
'11 " 1 J '' I '. ' i " 1 ;; ! '»
0.09
0.10 0.07 0.07
0. 10
0.02 0.05 . 0.02 0.03
0.02
0.03 0.02 0.02 0.02
o . '.- 1 f i fi | O.OI
'. l_- 0.11 0.10. 0. 10 O.O'I
0.22 0.17
- ~ *
..oi " 01
0.01 0.01 0.01 O.M
O..M 0.15
0. 11 . 0. 1.' 0.11 o. If
0. 13
11.21 0.23 0.20 0.16 O.I'.
".07 0.07 0.07 o.ni o.or,
0.06 0.06 0.05 0.05 O.oi
n.p* 0.06 o.-.-.;.->- If-l-'.i--
oot. Iin^ norT.i! tr>n no... «r- Itr;-- nor it t"n.
1 - t ' I '_"' ".;'. K ' ' ' ~ . . '<' "1J ''.' '-^~
0.07
0.09 o.rig o. in o.oi o.oi n.r.i
0.02 O.O2 O.OI O."! . O.'II 0.0[
o.oj 0.02 0.02 o.nj
('Ii (l.'.l 0. 1
ii.io n.os o.'iy u. in o.os o.r- Ji.li
0.00
O..T O.15 O.19 r- -.;. O.27 0 . r 3 d.'.O
0.01
o.oi o.oi' n. ni o.n]
0. 16
o.n o.i: (I.OB o.io - --.n 0.11 o.i"
(l.O'i
n.]-, O..M o.i". o.i' n.i" i . 2R o.2i o.ii
d.f'f, ii.ii' o.'i-, o.' 7 o.n'. ."r> !'.o3 iiq
O.C5 . O.O', 0.05
0.0.'. 0.0.', 0.07 0.05 0. 1 1
0.0'. O.OI 0.07
01'* (ill n 20
0 . f .' O. 05 0 . O5
n.-'f- «. li-. 0. .' ' 0. 'O
( | . II !>I 0.0 1
ll.fll'. 11.11'.
O.OI o.o.' o.oi o.nl
n.n i ii. n ;
I.I'' O ." '
-------
Table A-3 (Continued).
U.»r-
L. ~
V i
.w .
101
102
103
104
105
106
107
10S
109
110
111
it:
1 13
114
115
116 .
1 17
118
1 19
120
121
>22
'23
24
25
26
27
^8
29
30
31
32
b.Tif-
1-
1 ~!C
Hv:ir~cnr;' ~: ''-^-r *-:'' :t 1 \
3-F.tlwl-2-Pentenp
T-2-HcPtene
N-lleptane; 3-Me-C-2-He>:enc
Item 103 + 2, 3-Oinethy 1-r-Pentene
[te-n 103 + 2,3-Uinethy Icyc ! onen'one
Iton 104 " Item 101
2 , 3- Oime thv I- 2- Pen tone
Item 107 + C-2-Hcptcne; 3--Ethy Icyc lopentenc
C-2-Heptenc
Item 109 + 1-Ethylcyc lopentene
l-C-2-DtnethvIcyc lopcnt.inc
2, ?-Oimeth'.'l tiroin"
Item 111 + Item 112
Me-Cyc loher-ine ; 1,1, 3-1 r i-r>e thy Icyc Inpentane
2 ,5-Dtnethylhexane
Ethylcyclopentanc
2,4-Dimcthvlhexane
Item 116 * Ucn 118
2,2 , 3-1 rime thy 1 pen cane.
Iten 117 « Item 1 19
l-T-C-4-Tr imethycyc lopcnt.ine
3, 3-Dinethy Ihexane
Toluene '
l-T-2-C-3-Tr imp thy Icyc lopcntane
Item 122 * Item 121-Iter 124
Ethylhen.-.ene
P-Xylene
M-Xylene
0-Xytene
C-8 Saturates and Olefins
tsopropyt benzene
N-Propy Ibenzf ne
-ill : - -
:.-.
nor ..i 1
" 1 '
0.017
0.01
o.n
0.01
0.02
0.08
0."4
0.02
0.01
0.01
0.01
0.87
O.OS
0.04
0.12
0.08
0.3S
0.01
0.4
; .;
n ri i n "
top
''1 2
0.01
0.01
0.17
o.o:
0.02
0.09
0.04
0.02
0 . OA
0.01
0.01
0.86
0.01
0.05
0.05
0.12
0.06
O.'iS
T
0.01
.: i
b.i-'---
hfc. 1 "
C t . 1 1 "-"
.-: 1 1 :: ' .
0.01
0.1'.
0.01
0 .01
o.op
0.04
0.01
O.O?
0.01
0.01
0.83
O.Oi
0.02
0.11
0 . OS
0.11
T
7 r ' r -
; .
rii'i i I
0. 1 >
'» f j '
0.07
0.01
o.oi
o.o?
O.OI
0.6R
0.0?
0.02
0.07
0 . 04
0. 19
O.OI
...
i : i :> L. i , -
t.-n : . ! i n-
i '. ' ' ; :
0. 10
' . n
o.oi
' i i ' r . o ?
0.07 0.07
O.o? 0."?
(l.O? O.O]
o.o? o.nj
(i :,] O.OI
.0.01 O.0(
0 . -. 7 0 . S 7
o.oi o.o:
o.o: o.ot
0.09 O.OS
((.or, o.oi
O . ? ? 0 . ! Q.
T O.'M
0. 11 O.f, |
---.- ;.-. - -._...-.,.
- .,.: j ... k-, ;.... I ,,.:--
n;-r-i' : T "" ""' ''.'. r'n\~'' ' ~.~! ' ' :
" . - -^ '. _ . "- '' . ;' '' _ ' / " ~.
T
0.01 0.0] 'I.'! I
0.11
". M
11. 1'. 0. ; 7 0. 1-'. . '7
0.0-4
0.0? O.f-'. 0.01 0.0) n.o?
o.oi
rl n > ,(>'.i> o ( 1 f , . .
n n 1 ' t
. ' ' ) t :
O.n:
O.07 O.Oi O.OS 0."7 O.OS O.f'i '.10
o.o-', o.o? o.oi n.oi ' .: o.o? " . oi
o.n? o.ni o.f'!
n.o? o.oi o.o:
O.O' f O . i 1 . f 7
o.oi '>.''! o.'.' ' r
.--."
0.0] 0.01 O.n| 0.0? .' 0.01 0."?
**^- /\ f / */^T
' 'A f ' *i li *
M OM n *;i n "97 n , * - ...
. -^ * ' . , - -2S
. ' ' ' !* . '""i*1- --'**4\ f ^ * k f\X
ti.n-j o.n: o.o.'. __- l..o.)- T>.r-? -i.P'i
o m o.o? 0.03 o . r : 'o.o? o.o*
n|oq o.f..-, o.io 0.06 O.oi .1.10
n A ^ l'l rt ' /I rt ^ O ^l£
0.0'' 0.1)3 - 0. °M '>.0-* fl.'M '-.("I
n ; ' rv i o o . ;' w o ^ *<» '..*! 0 . 1 7 "» . 3 "*
»/ii nni *"- p ^
i ''*| MI'l , '
, i ^ ] f ' ' ] 0 . 0 1 * . 0 \
0'^ ' { --%
continued next-
-------
An.i Iv
Table A-3 (Continued) .
ot Air-Vapor rueii t" <*:-:icJi r 'con:'-J.
Item
No.
133
134
135
136
137
138
139
140
1411
It 2
'..-,
F.i!l
ba se-
V-
;: -,
Loadin;
line ncrnal
Hvdrnc.irh.~n Co-no-icTi:
1 -Me -3- Ethyl benzene
l-Me-4-Ethylbenzcnc
l->te-2- Ethyl benzene
1, 3 ,5-Trime thy 1 benzene
1 ,2,4- Frime thy 1 benzene
1 , 2,3-TrimP thy Iben :ene
C-9+ Saturates and Olefin=
l-Me-2-T.sopropylben7.ene
f 1 , 3- Dime thy 1-2- Ethyl benzene ; 1
1 , 3- Dime thy 1 -4 -Ethvl benzene
C-IO Saturates and Olefin1;
C-10 + Aroma t ic--
rf 1 1 « 1
0.
0.
0.
0.
1
n.
p.
1
01
02
05
01
06
OS
top
"1 ?.
0.02
0.01
.0.01
0.01
0.03
T
0 . 00
0.01
Winter IP
;r-
ba ^o- ' md i n'*.
hot. lir
«!
0.
0.
0.
0.
0,
ii .- i
,02
.01
,01
,01
.01
;e nor-n I
7 " ! 'i
O.OI
0.02
O.OI
O.OI
0.04
(I. 04
0.02
ton
-'' I '>
0.03
0.02
0.01
O.OI
0.0'.
0.02
0.01
0.02
ba-
c-
bot. line nor
« i c * :
o.oi
o.oi
0.01
o.oi
0.02
0.02
' I
0.
0.
0.
0.
n.
'^
0
'or:r- T"
I.oa-! i
-i! tc:r>
i.- 1 '_
'2 0.01
.01
,01
,"! 0.01
.03 0.01
--
h"
.» ;
0.
0.
0.
0.
0
f '
t e ->a "
* ' .
.03
.02
.01
.02
rv.
r|
. 03
1
c-: (>r ---
'-t^i-- ' - 1 : : -. :
! :~e nor T 1 t.^o. hi~:
*- '- .' - .-:;T ::J-
n . fi 2 r; . o i 0.02
r.'H
0.01 T 0.0]
0.03 0.01 0.01
".n? '.°2 O.n1
------- |