Note: Descriptions are shown in the official language in which they were submitted.
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BLENDED GASOLINES
Background of the Invention
Field o the Invention
The present invention relates to gasolines, and more
particularly to blended gasolines.
Descri~tion of the Relevant Art
Petroleum reserves are decreasing, and the cost of
locating and recovering new liquid gasoline reserves is
increasing. Large amounts of low-weight hydrocarbon
components and natural gasoline are available, but have not
been extensively utilized as fuels for motor vehicles and
other internal combustion engines. This is despite the
relatively low cost of these fuels. These fuels have a high
vapor pressure at standard temperatures and pressures, and
accordingly, vapor losses to the atmosphere by
open-container storage are environmentally unacceptable.
These ~uels are more difficult to store and to dispense than
currently available gasolines, and would require
modification of standard liquid gasoline burning vehicles.
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Summaxv of the Invention
It is an object of the invention to provide a fuel for
internal combustion engines which utilizes low-weight
hydrocarbon components and natural gasoline resources.
It is another object of the invention to provide a
liquid fuel for internal combustion engines.
It i5 still another ob~ect of the invention to provide
a fuel for ir.ternal combustion engines with an
environmentally acceptable vapor pressure.
It is another object of the invention to provide a fuel
for internal combustion engines with an acceptable octane
rating.
It i~ yet another ob~ect of the invention to provide a
fuel for internal com~ustion engines which can be produced
at relatively low cost.
These and other objects are accomplished by blendinq a
butane-pentane rich (hereinafter "low-weight hydrocarbon")
component, a natural gasoline component, and a toluene
component. The low-weight hydrocarbon component can
comprise a mixture of hydrocarbons having from about 2
carbons to about 7 carbons in varying proportions. It is
preferable, however, that at least 50 volume percent of the
low-weight hydrocarbon component should be 4 and S carbon
hydrocarbons. The natural gasoline component preferably
contains hydrocarbons from about 4 to about 12 carbons.
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Most preferably, the natural gasoline component contains atleast 65 volume percent of 5 and 6 carbon hydrocarbons and
at least 25 volume percent of 7 or greater carbons. The
toluene component should be relatively pure, although up to
about 10 volume percent of the toluene component can be
benzene and other 6 and 7 carbon hydrocarbons.
The natural gasoline and low-weight hydrocarbon
components can be initially blended together in a weathering
process in which light-weight hydrocarbons are withdrawn as
vapor from the process. The blending is provided by one or
more recirculation pumps which provide for thorough mixing
of the components. The light-weight hydrocarbons which are
released from the liquid blend can be burned to generate
energy to power the pumps and to provide for the other
energy requirements of the process. Toluene is then
preferably added and mixed with the blended natural gasoline
and low-weight hydrocarbon components. The weathering
process continues for about 8-12 hours to allow for thorough
mixlng of the components and a reduction in the amount of
light-weight carbons in the mixture.
The resulting product will be a liquid fuel with about
10-35 volume percent low-weight hydrocarbons, about 30-60
volume percent natural gasoline, and about 20-40 volume
percent toluene. The proportions of the components can be
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ad~usted to vary the octane rating and vapor pressure of the
product gasoline.
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~rief Descxi~tion of the Drawinas
There are shown in the drawings embodiments which are
presently preferred, it being understood, however, that the
invention is not limited to the precise arrangements and
instrumentalities 6hown, wherein:
Fig. 1 is a schematic view of a process and apparatus
according to the invention, partially broken away for
clarity.
Fig. 2 is a cross-section taken along line 2-2 in Fig.
1.
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Petailed Description of the Preferred Embodiment
Blended gasolines according to the invention are
produced by blending a low-weight hydrocarbon component, a
natural gasoline component, and a toluene component. The
low-weight hydrocarbon component can contain hydrocarbons
having from about 2 to more than about 7 carbons, and in
varyinq proportions. It is preferred, however, that at
least about 50 volume percent of the low-weight hydrocarbon
components be butanes and pentanes. The natural gasoline
component preferably comprises pr$marily hydrocarbons having
about 4 to about 12 or more carbons. At least about 65
volume percent, however, of the natural gasoline component
should be pentanes and hexanes, and at least about 25 volume
percent should preferably have about 7 or more carbons. The
toluene component should be at least about 90 volume percent
toluene, although benzene and other low-weight hydrocarbons
can be included in 6mall proportion, which preferably does
not exceed about 10 volume percent of the toluene component.
The natural gasoline components can be extracted from
natural gas sources consisting mainly of methane. Most of
the methane, together with ethane, propane, and some
butanes, exit from the process with only the natural
gasoline being condensed and collected by suitable methods
known in the art, including cascade refrigeration extraction
processes. These methane rich streams, free of natural
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gasoline components, are used principally as a fuel in homesand in power generating stations. Excess low-weight
hydrocarbons can be sold separately.
It i8 preferable to initially blend the natural
gasoline component with the low-weight hydrocarbon
component. It i5 preferred to include about three volume
percent extra of the low-weight hydrocarbon component to
allow for weathering losses of ethane, propane and some
butane. Light-weight hydrocarbons remaining in the mixture
are weathered off during the blending operation, and can be
combusted to generate power and to run pumps used in
blending. The low-weight hydrocarbon component is mixed
with the natural gasoline component in about a 1 to 3 volume
ratio, respectively.
The components are mixed together thoroughly by
suitable mixing apparatus, and a vapor stream is withdrawn
from the mixture to remove light-weight hydrocarbons
including ethanes, propanes and some butanes. The pressure
i8 preferably maintained at about 0-15 psig, which allows
the light-weight hydrocarbon vapors to be withdrawn from the
process and passed to storage or a power generating station.
Toluene is added to the low-weight hydrocarbon/natural
gasoline mixture such that the toluene is approximately
20-40 volume percent of the mixture. The mixture is
agitated to blend the mixture together and to facilitate the
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release of vapors. A vapor stream ~s again removed during
the mixing process to withdraw light-weight, high vapor
pressure hydrocarbons.
The liquid mix is preferably agitated in an enclosure
having a vapor space. Vapor collects in the vapor space and
liquid collects in a liquid space of the enclosure. ~he
vapor stream is withdrawn from the vapor space. The
agitation can be created by directing the liquid mixture
into a dispersing object positioned in the enclosure. The
mixing process preferably continues as a batch process for
approximately 8-12 hours. Intermediate storage tanks can be
provided to collect the mixture. Recirculation pumps can be
utilized to return the liquid from the 5 ntermediate storage
tanks to the agitation/mixing step.
Condensing apparatus can be provided to condense
low-weight hydrocarbons from the vapor stream, and these
low-weight hydrocarbons can be returned to the mixing
process. The condensing apparatus can be of any suitable
design, but preferably has a large amount of condensing
surface area. A presently preferred mixing apparatus
according to the invention is shown in Figs. 1-2. A number
of storage tanks 10-13 can be provided, although more or
fewer storage tanks can be provided if desired. The liquid
components to be mixed can initially be stored in the tanks
10-13. Liquid exits the tanks 10-13 through a liquid return
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2007~87
path 14 and by operation of valves 15-18. Liquid from the
return path 16 enters one or more hiqh output liquid pumps
20 through a pump inlet path 22. The pump 20 moves the
liquid to an agitating apparatus, such as the mixing column
24. A riser conduit 26 conducts the liquid to the top 25 of
the column 24. The liquid exits the riser conduit 26 in the
downward direction, and can be directed at a center surface
30 of a splash tray 32. Liquids pass the splash tray 32
through openings 33. The splash tray 32 can be constructed
from many alternative designs, but is intended to aqitate
the liquid to promote mixinq and ~he release of light-weight
hydrocarbon vapors. Alternative means known in the art for
aqitatinq liquids, such as impellers, pipe mixers, and
packing, and for removing vapors from liquids, could also be
utilized.
Vapors accumulate in, and are withdrawn from, a vapor
space at the top of the mixinq column 24. The vapors exit
the column 24 through a vapor outlet path 34. Some vapors
will condense in the vapor outlet path 34, and are returned
to the tanks 10-13 throuqh a vapor manifold 36 and vapor
return paths 38-41. Vapors exiting the vapor manifold 36
are preferably processed in one or more ~ondensation steps
to condense and return to the process any low-weiqht
hydrocarbons which may be present in the vapor stream. A
condensor apparatus 44 is filled with a packing 46, which
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can be selected from several suitable materials and designs
which will provide the requisite surface area for
condensation of the low-weight hydrocarbons. Vapors can
enter the condensor apparatus 44 through a packing column
inlet 48 and exit through a condensor outlet 50. Liquid
hydrocarbons condensed in the condensor apparatus 44 fall
under the influence of gravity into the vapor manifold 36
and return to the storage tanks 10-13 through the vapor
return paths 38-41. Alternative condensing operations are
also possible to condense low-weight hydrocarbons from the
light-weight hydrocarbon vapors.
The vapor~ leaving the condensor apparatus 44 through
the condensor outlet 50 will consist primarily of
light-weight hydrocarbons such as ethanes, propanes and some
butanes. These hydrocarbons can be combusted in a suitable
power generating station 35 to provide energy through a path
37 to run the circulation pumps 20, and to provide for the
other energy requirements of the process.
Liquids passing through the openings 33 in the splash
tray 32 collect in a bottom 54 of mixing column 24. Liquid
outlets 52 are preferably provided in the sides of the
mixing column 24, and are preferably spaced upwardly from
the bottom 54 of the column 24. Liquid hydrocarbons will
accumulate in the column to the level of the outlets 52, and
will flow out of the column through the outlets 52 into one
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or more liquid outlet manifolds 58. Liquid in the liquid
outlet manifolds 58 is returned to the storage tanks 10-13
through liquid return paths 60-63. The liquid outlets 52
may be positioned in a number of locations in the column 24
below the splash tray 32. The liquid outlets 52 are
preferably positioned in the column 24 at a height greater
than that of the storage tanks 10-13 to permit gravity flow
of the mix from the liquid outlets 52 to the liquid return
paths 60-63. Mixture accumulated in the bottom 54 of the
tank 24, below the liquid outlets 52, can be recirculated to
the pump 20 through a recirculation path 66, which can be -
controlled by operation of a valve 68.
The product gasoline is pumped from the tanks 10-13 and
the column 24 when the weathering process is complete. A
valve 72 in the riser path 26 can be closed, and an exit
path control valve 74 is opened. The pump 20 then operates
to move the gasoline through an exit path 7& to product
storage tanks.
The apparatus according to the invention can be
constructed from other suitable process components. The
number and layout of the tanks 10~13 can be varied.
Alternative pumping arrangements are also possible. It is
possible to replace the column 24 with another mixing
apparatus, for example, a pipe mixer apparatus, and to
provide alternative means for withdrawing a vapor stream
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from the mixed product. It is also possible to run theprocess as a continuous process, as contrasted with the
batch process described herein. It is also possible to
utilize alternative designs to the splash tray 32. The
condensor 44 can be replaced with other suitable condensor
means, including chilled water condensors, to remove
low-weight hydrocarbons from the vapor stream.
The proportions of natural gasoline, low-weight
hydrocarbon, and toluene components can be adjusted to vary
the resulting octane rating and Reid vapor pressure of the
resulting gasoline. A lower octane gasoline, of perhaps 87
octane, and w~th a Reid vapor pressure of about 12 psig and
an initial boiling point of about 90 degrees F, as might be
useful in a winter gasoline, would preferably have the
following approximate composition:
25-35 volume percent low-weight hydrocarbons
40-50 volume percent natural gasoline
20-30 volume percent toluene
A summer gasoline mix having an octane rating of about 87
and a Reid vapor pressure of about 9 psig, together with
initial boiling point of about 80 degrees F, would
preferably have the following composition:
10-15 volume percent low-weight hydrocarbons
50-60 volume percent natural gasoline
20-30 volume percent toluene
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A winter mix gasoline having a high octane rating ofapproximately 92, together with a Reid vapor pressure of
about 12 psig and an initial boiling point of about 90
degrees F would preferably have the following approximate
composition:
25-35 volume percent low-weight hydrocarbons
30-40 volume percent natural gasoline
30-40 volume percent toluene
A summer gasoline mix having a high octane of about 92 and a
Reid vapor pressure of about 9 psig, with an initial boiling
point of about 80 degrees F, would preferably have the
following approximate composition:
10-15 volume percent low-weight hydrocarbon
45-55 volume percent natural gasoline
30-40 volume percent toluene
These proportions are preferred, but it will be understood
that the preferred proportions can vary depending upon the
precise composition of the various low-weight hydrocarbons,
natural gasoline, and toluene components. It may be
possible, for example, to substitute an alternative
octane-boosting component in addition to toluene, although
toluene is presently preferred.
EXAMPLE
The following example is provided for purposes of
illustration, it being understood, however, that the
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invention i8 not limited to the precise compositions
disclosed herein.
Feed compositions are provided having the following
characteristics:
~edium-weiaht Hydrocarbons
Component Weiaht %
Propane 0.2
Isobutane 2.2
n-butane 25.1
~ydrocarbons having 5 or
more carbons 72.5
100. 0
Reid Vapor Pressure 0 100 degrees F l9 PSIG
Pump Octane No. 76
Specific gravity Q 60 degrees F 0.65
Natural Gasoline
Comonent Weiaht %
n-butane 4.0
i-pentane 15.0
n-pentane 23.0
hexanes 26.0
heptanes, and higher-
carbon hydrocarbons32.0
100. 0
Reid Vapor Pressure ~ 100 degrees F 9.5 PSIG
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Pump Octane No. 76
Specific gravity Q 60 degrees F. 0.75
Toluene
Component yolume %
Toluene 99.9
Pump Octane No. greater than 100
Specific gravity @ 60 degrees F. 0.87
The above-described liquid components are blended by
first blending the low-weight hydrocarbon component with the
natural gasoline component in about a 1 to 3 volume ratio,
respectively. About 3 volume percent extra of the
low-weight hydrocarbon mix is added and weathered off during
the blending operation. The toluene is then added to this
mixture in about a 1 to 3 volume ratio, respectively. In
the example embodiment, the tan~s 10-13 each ha~e a 30,000
gallon capacity. The column 24 is approximately 64 feet
high, and approximately 26 inches in diameter. The ri~er
26, liquid manifolds 58, and conduit 16 are each 4 inch ID
conduit. The vapor line 38 is 2 inch ID conduit. The pump
20 is a high output, 900 gallon per minute pump.
The pump 20 is operated to circulate t~e liquid
components from the tanks 10-13 to the top of the column 24.
The liquid components are sprayed directly onto the center
30 of the splash tray 32 to agitate the liquid and to permit
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vapors to separate from the liquid components. Liquidvapors exit the column 24 through the vapor outlet path 34,
and low-weight hydrocarbons are recovered from the vapor in
a condensor unit 44. Condensed vapors and liquid from the
column 24 ars returned to the tanks 10-13, and again are
circulated by the pump 20. The column 24 is operated at a
pressure of about 15 psig.
The mixing operation continues as a batch process for
approximatély 8-12 hours, until the mixture is substantially
homogeneous and until the composition is approximately 15-
volume percent low-weight hydrocarbons, 55 volume percent
natural gasoline, and about 30 volume percent toluene. The
gasoline produced by the above-described process will have a
vapor pressure between about 9-12, and an octane rating of
between about 87-92.
This invention can be embodied in other specific forms
without departing from the spirit or essential attributes
thereof, and accordingly, reference should be had to the
following claims, rather than to the foregoing
specification, as indicating the scope of the invention.
