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Патент USA US2105464

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Patented Jan.‘ T8, 193
,iati
2,105,464
‘~ :I E ACTURE 0F MOTOR FUEL
Waldo 0. am an Carroll A. Hochwalt, Dayton,
@hio, assignors to Monsanto Chemical Com
> pally, St. Louis, M0,, a corporation of Dela
ware
No Drawing. Application .iune 29, 1938,
Serial No. 87,910
6 Claims. (Cl. ISIS-23)
The present invention relates to a process of
treating gasoline, motor fuels, and similar dis
tillates to improve their properties, especially in
regard to gum formation, sulphur content,,and
similar characteristics.
-
The principal object of the invention is to pro
vide a more efficient and economical method of
producing gasoline and similar motor fuel dis
tillates.
Heretofore, it has been proposed to remove
10
gum from gasoline by treatment with various
reagents. Not infrequently a reagent such as
phosphoric acid, zinc chloride solution and the
like, will remove the gum from a particular petro
leum product but will not remove enough of the
sulfur impurities to pass the speci?cations for
motor fuels without ancillary chemical treat
ment.
,
The- present invention affords an inexpensive
and convenient means for accomplishing substan
tially complete degumming of a gasoline product
and sufficient desulfurization to pass the sulfur
speci?cation even in the case of the very sour
grades of petroleum products.
According to the present invention a gasoline
I
is treated with a metal'oxide, such as an alkaline
ferric oxide, and then subjected to a treatment
economical manner without producing any sub
stantial reduction in the other desirable proper
ties of the original fuel. The process of the in
vention usually produces an enchancement of
the antiknock value of the fuel instead of the 5
diminution thereof obtained by other re?ning
methods.
.
According to one method of practicing the in
vention, the unre?ned fuel is passed in vapor
form over Alpha-Lux (which is commercially 10
available precipitated ferric hydroxide that is
strongly alkaline and used extensively in the in
dustrial and domestic gas industry) at a tem
perature of 375° to 425° C., at such rate or time of
contact, that substantially no cracking results.‘
A suitable rate for a furnace consisting of a heat
5
ed tube of 1%,," internal diameter and 5 feet long
?lled with the ferric oxide in granular formis 1A2
gallon of liquid fuel per hour. The vapors are
then scrubbed with phosphoric acid maintained
at a temperature of about 190° to 200° C., ‘and are
subsequently condensed. The optimum tempera
ture for the oxide treatment will vary according to the time of contact, the activity and age
of the catalyst, the amount and form of the sul
fur impurities in the product and the extent N)5
of sulfur removal required. A suitable method
. with phosphoric acid whereby a marked reduction which we have used to establish the temperature _
in sulfur content, as well as in gum-forming con ' of operation. is to test the ?nal petroleum prod
30 stituents, is effected, while at the same time the
ole?nic nature of the fuel is not substantially af“
fected. The fuel thus treated is remarkably sta
ble with respect to gum and color.
Heretofore the methods of removing gum~
35 forming constituents from gasoline and similar»
distillates, for example, the we1l~known re?ning
treatment with sulfuric acid, resulted in a lower
ing of the ole?n content of the distillate, as well
as a reduction in the gum value. A'lowering of
40 the ole?n content is undesirable due to the. loss
of fuel thus produced, and the reduction in anti
knock value of the re?ned distillate. On the
other hand, the methods of reducing the sulfur
content of fuels now in use, such as the doctor
45
treatment and alkaline hypochlorite solutions,
are expensive and furthermore, yield fuels un
I stable with respect to gum and color. The proc
ess of this invention obviates such treatments
and makes it possible'to effect marked vreductions
in gum ‘value and sulfur content in a simple and
uct to determine the effectiveness‘ of this ?rst
step. As the activity of the oxide diminishes the
temperature is increased. When effective re
moval of sulfur is not longer economically pos
sible, the oxide is regenerated in the known man
ner, preferably with steam, or steam and air. To
remove dissolved hydrogen sul?de and the like,
the condensate may be washed with a mild aque
5
ous alkali or caustic alkali.
By such a treatment a, gasoline has been im
proved as shown in the following table. In
40
column I are shown the properties of the original
fuel; column II shows the change produced when
the vapors are not subjected to the subsequent
phosphoric acid treatment, that is, when the va
pors are passed only through the ferric oxide;
column III represents the improvement obtained
by the process as described; column IV shows the
improvement obtained by treatment with phos
phoric acid alone. The properties weredeter
mined by the customary methods and were de
50
2
aroaaea
termined by exactly the same procedure for each
sample.
III
Origi
nal
Ferric Improved Phosphoric
oxide
acid treat-v
process
ment
treated
value (copper dish
10 Gum
method, milligrams)_-__.
456
422
stability, minutes) _____ -_
30
70
Gum test (oxygen bomb
IV
2
6
220
Total sulfur content (lamp
0. 2O
0. l2
0. 11
0 ____________________ __
0.46
Absent
0.015
bromate, centigrams)____
54
52
'
method, %) ____________
__
Mercaptan sulfur content
15 Unsaturation (bromide
49
50
has a higher boiling point than the original gaso
line passed through the acid and on distillation
it yields a clear light colored liquid with a blue
fluorescence which is believed to consist of poly-'
mers of some of the original gasoline constituents.
It is desirable to control the temperature of the
phosphoric acid chambers so that little ornone of
these polymers are volatilized with the vapors.
‘To prevent any spray of phosphoric acid or poly
mer during the treatment, the apparatus is pro 10
vided with suitable ba?les or towers packed with
any non-reactive filling material such as glass,
coal, coke, etc. These provisions are more fully
described in the applications of Carroll A. I-Ioch-v
Walt and Waldo C. Ault, to which reference has
already been made.
-
The improved process of using ferric oxide with
I
20
11
Positive
Poor
C
_
Octane rating
IV
Negative
Negative .
Excellent
Poor
Positive
Excellent
‘
(antiknock)__'__
60
60
G3
63
a phosphoric acid treatment produces a result
heretofore unexpected of a combination of the
two processes. The treatment with the ferric
oxide, in some manner which is not clearly under
stood at present, besides removing a definite pro
portion of the sulfur bodies present in the original
Similar advantageous results have been ob- ' distillate, leaves the unremoved residual sulfur
25 tained with a Wide variety of gasolines of differing
properties. The method is particularly valuable
for ‘fuels with high sulfur contents and high gum
values.
30
'
,
The treatment with phosphoric acid may be
carried out in the vapor phase as described here
inabove or as further described in the application
of Carroll A. Hochwalt and Waldo C. Ault, Serial
Number 66,896, filed on March 3, 1936. Alter
' native procedures consist in effecting the ‘treat
ment with'the aid of steam, or conducting the
treatment in the liquid phase, as described in
the applications of Carroll A. Hochwalt and Waldo
C. Ault, Serial Numbers 66,893 and 66,895, ?led
on March 3, 1936. The‘ phosphoric acid may be
40 dispersed on pumice, clay or similar solid material
to increase its surface of contact with the mate
rial undergoing treatment. For some purposes a
treatment with the phosphates of copper, nickel,
cadmium, zinc, cobalt, chromium, iron and other
45 metals, according to the method described in the
application of Carroll A. Hochwalt and Waldo C.
‘Ault, Serial Number- 66,894, ?led March 3, 1936,
is preferred. When such solid agents are used
the treatment can be conducted in two separate
50 ‘units, such as a tube containing ferric oxide and
another tube containing the metallic phosphate.
55
or the two catalysts may be placed in the same
tube, or the two solid treating agents may be in
termingled and used in va single unit.
A concentration of phosphoric acid especially
appropriate for the practice of the invention is
one which corresponds to tetrapyrophosphoric
acid (H6P4013), which has a phosphorus pentox
60 ide (P205) content of approximately 84%. This
acid can be made by adding to phosphoric acid,
bodies in what might be called an activated con
25
dition, that is, in such a condition that they are
more completely removed in the subsequent phos
phoric acid treatment. It has been found that
less advantageous results are obtained if the
phosphoric acid treatment precedes the desulfur
30
ization treatment and that when two gasolines,
(1) an unre?ned gasoline, and (2) a gasoline pre
treated with ferric oxide, both with an equivalesnt
total sulfur content and corresponding in other
properties, are treated with phosphoric acid in 35
exactly the same way as described herein, that
gasoline previously treated with ferric oxide will ‘
have a lower residual sulfur content than the
gasoline not previously treated. The action of
the ferric oxide appears to affect favorably the
susceptibility of the sulfurto removal by treat
'ment with phosphoric acid or similar gum remov
ing reagent. While the treatment with phos
phoric acid to remove the gum is preferred and
possesses distinct advantages, other known means 45
for accomplishing this step by polymerization may
be employed’. For example, acid reacting salts
and aqueous solutions thereof have been proposed
for this step, such as zinc chloride and the like.
The function of the ferric oxide from ,the above 50
considerations is primarily that of rendering the
sulfur compounds in the original gasoline more
completely susceptible to removal. Other mate
rials which are effective, especially when ren
dered distinctly alkaline or basic, are: iron ores, 55
copper oxide, bauxite, aluminum oxide, lead ox
ide and calcium oxide; in general, alkaline metal
lic oxides or hydroxides may be used.
Salts or
metals which can give rise to metallic oxides
during the treatment may be employed by placing 80
for ‘example, commercial syrupy acid having a " them in the tube or other suitable apparatus and
phosphorus pentoxide content of about 55%, an treating them in such a manner that the oxide
additional amount of phosphorus pentoxide until remains; thus, for example, the tuoe maybe
filled with iron ?lings and air passed therethrough
65 an acid of the appropriate concentration is ob
tained. Phosphoric acids ‘containing additions at a raised temperature until oxidation to ferric
of phosphorus pentoxide such that their contents
of phosphorus pentoxide range from about 50 per
cent and upward, produce satisfactory results in
70 re?ning most gasolines, but the optimum concen
tration of the acid and conditions for its usefor '
any particular purpose are easily determined by
previous tests. In the phosphoric acid, a dark
colored liquid will be seen to deposit during the
75 process of treating crude gasolines. This liquid
oxide has‘been accomplished. During the treat
ment some metal sul?des may be formed.
Oxida- -
tion with air at a raised temperature,-preferably
with the addition of steam, is sufficient to recon
vert these sul?des to oxides. The oxide, especi
ally when strongly alkaline, activates the sulfur
compounds in the original distillate to a form
whereby they are more easily removed in the sub
sequent step and need not of itself have any de
70
sulfurizing action.
75
3
I 2,105,464
Inasmuch as the conditions and reagents speci
?ed above comprise preferred embodiments of the
invention, it is to be understood that the inven
tion is not limited thereto, nor to any theory of
the chemical actions herein involved, but is sub
.iect only to the limitations de?ned in the ap
pended claims.
What we claim is:
1. In the treatment of a cracked distillate of
10 motor fuel boiling range, rich in sulfur and gum
forming constituents, to form a distillate of motor
fuel quality, the steps which include subjecting
the distillate while in vapor phase to a metal
- oxide which has been rendered distinctly alkaline,
15 ‘
whereby sulfur impurities are rendered removable
forming constituents, to form a distillate of motor
fuel quality, the steps which include subjecting
the distillate while in vapor phase to a distinctly
alkaline ferric oxide, whereby sulfur impurities
are rendered removable by phosphoric acid treat
ment and subsequently scrubbing the distillate
with phosphoric acid under conditions whereby
polymerizable and surfur containing impurities
are removed without substantially reducing the
octane number of the motor fuel.
10
4. In the treatment of a cracked distillate of
motor fuel boiling range, rich in sulfur and gum
forming constituents, to form a distillate of motor
fuel quality, the steps which include subjecting
the distillate while in vapor phase to a distinctly 15
by phosphoric acid treatment and subsequently
scrubbing the distillate with phosphoric acid
under conditions whereby polymerizable and
sulfur containing impurities are removed with
20 out substantially reducing the octane number of
the motor fuel.
alkaline ferric oxide, whereby sulfur impurities
are, rendered removable by phosphoric acid treat
ment and subsequently scrubbing the distillate
2. In the treatment of a cracked distillate of
motor fuel boiling range, rich in sulfur and gum
forming constituents, to form a distillate of motor
without substantially reducing the octane number
25 fuel quality, the steps which include subjecting
the distillate while in vapor phase to an alkaline
ferric oxide, whereby .sulfur impurities are ren
dered removable by phosphoric acid treatment
and subsequently scrubbing the distillate with
30 phosphoric acid under conditions whereby poly
with a polymerizing agent under conditions
whereby polymerizable gum forming and sulfur 20
containing impurities are rendered removable
of the motor fuel.
5. The method as de?ned in claim 4 and further
characterized in that the ferric oxide treatment 25
is effected at approximately 375-425° C. and the
phosphoric acid treatment is effected at approxi
mately 190-200° C.
merizable and sulfur containing impurities are
6. The method as de?ned in claim 4 and char
acterized in that the ferric oxide is substituted by
an alkaline oxide of another metal which has
removed without substantially reducing the oc
been rendered distinctly alkaline.
tane number of the motor fuel.
_
3. In the treatment of a cracked distillate of
35 motor fuel boiling range, rich in surfur and gum
I
WALDO o. AUL'II‘.
CARROLL A. HOCI-IWALT.
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