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Патент USA US2406210

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Patented Aug. 20,_ 1946
2,406,216
f.f
UNITED STATES¥ PATENT OFFICE
:METHOD> OF CONTROLLING W
' SWEATING
‘
‘
Seymour W. Ferris, Mount Holly, N. J., assig'nor to
The Atlantic Refining Company, Philadelphia,
lr’a., a corporation of Pennsylvania
Application octòber 19, 1942, serial No. 462,653
' 7 claims.
1
.
-
_ Y The present f'invention relates VVto the sweating
(c1. 19e-'20)
'
.
2
ing point. For convenience, the `melting `point is
of oily wax to reduce the oil content thereof, and
relates more particularly to improvements in con
trolling the sweating of such wax.
An object of this invention is to control wax
D87-37 “Melting point of paraliin wax,” and the
sweating in such a manner as to produce high
_In accordance with the present invention, use
. yields of wax of reduced oil content without sub
determined in accordance with A. S. T. M. Method
refractive index is measured at 176° F. in a suit
able refractometer.
~
_
'
is made of the relationship of the melting point
stantial loss of desirable wax in the sweat oil.
and refractive'index of the sweated wax and the
` A further object of this invention is the applisweat stream in controlling the duration of the
cation to wax sweating of a control method in 10 sweating operation. More specifically, a sample
which" the control factors may be determined
easily and rapidly, and the results thus obtained
immediately applied in controlling the sweating
operation.
`
of an oily wax is experimentally sweated by slowly
raising the temperature of the mixture, and suc
cessive samples of the material sweated from the
mixture, i. e., the sweat stream, are taken. The
The sweating of oily wax is generally carried 15 meltingl point, refractive index, and oil content
out for the purpose of removing oil from the wax,
and has long been used for the deoiling of paraf
of each of the samples is determined, and the oil
content of the sweated wax may also be deter
ñn wax, such as slack wax obtained from the
pressing of parañin distillates. Slack wax usual
mined at each interval at which a sweat stream
ly contains from 25% to 40% by weight of oil,
and from such oily wax is made a variety of wax
'products of reduced oil content. For example,
a commercial product such as scale wax contains
sample is taken. YFrom the'refractive index-melt
ing point relationship of the sweat stream sam
ples and the oil contents of the sweat stream and
sweated wax samples, it is thus possible to deter
mine experi-mentally the point Vat which sweat
ing should be stopped in order to obtain a ñnal
from 8% to 10% of oil, whereas fully reñned par
aflin wax contains less than about 4% ofoil, and 25 wax having a desired oil content. The results
high tensile strength paraiñn wax contains less
thus determined experimentally for a given wax
than 1.5% of oil, all of the oil contents being
stock may then be applied directly to the control
determined by treatment with ethylene dichlo
of a large scale commercial sweating operation.
ride as described more fully hereinafter.
For example, a given wax stock is sweated on
Heretofore, in the sweating of oily wax, it has 30 large scale and successive sweat stream samples
been very diiiìcult to judge when the oil has been
are taken. The melting point and refractive in
completely removed, or removed to the desired
dex of each sample is determined as rapidly as
extent, from the wax remaining in the sweat
ing pans. This diñiculty arises from the fact
that it is practically impossible to obtain a sample
representative of all of thewax remaining in
the sweating pans, and in addition, the deter
mination of the oil content of the sweated wax
the sample is taken from the sweat stream.
When the refractive index-melting point rela
tionship of a sweat stream sample is found to
correspond to an experimentally determined
value indicating a known oil content in the ex
perimentally sweated wax or sweat stream sam
by a selective solvent method is time-consuming.
ple, the large scale sweating operation is stopped
_When more than one cycle of sweating is em 40 and the resulting sweated wax will be found to -.
ployed for the production of a- fully sweated
have, substantially the same oil content as the
wax, there is a greater likelihood that the ñnal
experimentally
sweated wax. Thus, by simply
product will be substantially oil-free, but when
single cycle sweating is carried out, the determi
determining the refractive‘index-melting point
nation of the proper time to terminate the sweat 45 relationship of a sweat streamV sample from> a
commercial sweating oven and comparing it with
ing Ábecomes more important, since stopping too
the refractive index-melting point'relationship
soon results in incomplete oil removal and low
of sweat stream samples predetermined experi- ,
tensile strength, and if each run is carried far
mentally for sweated wax of'known oil content,
enough to insure the lproduction of high tensile
strength wax, the average yield of the wax will 50 it isy possible to control closely the large scale
be reduced.
,
,
It has been found that one of the most distinc
tive properties of a wax is the relationship be
sweatingiof wax and to stop the sweating at ex;-
actly the proper time so that the wax is neither
under-sweated nor over-sweated.
Since the re
tween its melting point and its refractive index
fractive index and melting point of the sweat
.measured at some temperature above its melt 65 `stream samples are easily and rapidly deter
2,406,210
3
Y
~
_` .
ï
.4
,
the sweating operation'at the proper time.
The present invention may be further under
stood with reference to the accompanying draw
ing, which illustrates the relationship between
inch.
the refractive index and melting point for sweat '
Sweat stream
Sweated wax
-
_
R. I., „
P.,
°F.
'
.
Manufaturing Company, the aurometer scale be
ing calibrated from zero to 100. The 100 durom
eter reading indicates no penetration, while thev
zero reading indicates complete penetration.
Tensile strength of thewax isgiven in lbs/square
minable, there is little or no lag in shutting down
176° F.
Í"
_
Percent`
'o‘
Y
P., _ Percent
' ‘
°F.
oil
Hardness
Tensile
cent yield
strength
86° F.
E
111382
,
-
95
`37.5
F
1 .4350
99
28 .5
G> .
l .4291
109
14.9
Y:El:
1.4280
„115
I
-1 .4273
120 .
J
l .4275
_
Weight per-
95° F.
__________ ___._Y_____
'
'
8.6
126.6
2.0
29.8
4.1
129
l .0
23 .2
30
0
132
1 .1
133 .5
0 .3
6 .3
90
30
378
127 .5
stream samples from a commercial slack wax, 20
and the correlation of such -relationship with the
oil'k content _of the sweat stream samples and of
the sweated wax.
Referring to the drawing, in which-refractive ,
__________________________ _.
Referring again to the drawing, _the constitu
ents of a hydrocarbon wax, such as asubstan
tially oil-free parafün Wax, have refractive index
melting point relationships which f_all within Ythe
area defined -by the lines AB and CD.
Liquid
index is plotted against melting point, the lines 25 constituents of parañin distillate, however, Vex
hibit relatively high refractive indices, and when
AB and CD represent the limits within which lie
the refractive index-'melting point relationship of
the majority of the hydrocarbons present in sub
the first sweat stream sample is found to lie, for
stantially oil-'free waxes. The pure straight
example, at point E, it is'îmmediately known `that
chain parañin hydrocarbons will be foundV to lie
along theline AB, whereas the substantially Voil 30 considerable oil is present. When Ythe slackwax
is subjected to further sweating, however, the
free waxes may lie vanywhere within the area de
sweat stream shows progressively less> oil Vand
fined vby AB and CD._ The equation for the line
therefore the points will be found to movev to the
AB is.11.=`1.3950+.000242T, and the equation for
_ left as indicated at F, G, H, and I on the drawing.
the line CD is _n=l.3793+.0004T, “n” being the
At such time as the quantity of oil in thesweat
'refractive index at 176° F., and “T” being the A. S.
T. M. melting pointf‘F.
‘
, Upon the drawing is also plotted _a curve de- '
stream samples has reached a very, low value, for
example, ypoint I, the successive point'swill no
fined by the points E, F, G, H, I, and J, represent
ing Ythe refractive index-melting point relation
longer proceed to the left of the drawingV but will
ships _of successive sweat stream samples from an
inasmuch as _such samples areapproaching the
experimentally sweated vheavy parañîn slack wax
having an initial oil content of 33.4% by weight
' composition of substantially pure wax (point J )",
and a melting point‘of 106° F. The oil content of
' the slack wax, aswell asthat of the sweat stream
samples and sweated wax, was determined by the
following method.
_
'
>
'
25 grams of oily wax is dissolved in ethylene
vdi'chloride 'and made upto 500 cc. at room tem
rise, due to the increasing> melting points, _and
Y'the
'Whenpointsl
'such condition
will roughlyr
is reached,
parallel
thethe
waxline,
remain
ingin the sweating pans is substantially freeofV
oil. For any particular wax’stock, it may bede
termined experimentally how close the refractive
index-melting pointk value yof the sweat stream
» must approach the line AB before the 'sweated
perature (75° F.) , the solution is then cooled with
4'stirring to 5° F. and filtered at such temperature
‘.wax remaining'inth‘e pans is of desired quality.
through rapid filtering qualitativeY filter paper.
and the position of the Vcurve on the accompany
ing drawing may change as either the vboiling
range or the sourceof the wax distillate, and
The wax on the filter is then thoroughly washed
f _with ethylene dichloride at 5° F., and an aliquot
Each wax stock has a particular curve of its own,
portion of the filtrate (100 cc.) , measured at< room
therefore the wax stock, varies.
temperature (75° F.)_is transferred to a weighed
In order to produce from a slack wax stock hav
ing an oil content of from 25% to 40% by weight,
a commercial grade Vof scale wax having-an oil
evaporating dish, and the ethylene dichloride is
'
_
removed by evaporation at 220° F., using a cur
rent of air to sweep out the vapors. A partial
content of 8% to 10%, it has been found _that
the refractive index-melting point relationship of
vacuum may be applied when most of the ethyl
ene dichlor’ide has been removed, in order to fa GO the sweat stream should fall. within the
limits defined by lines. having the equations
cilitate Vthe removal of the Ylast traces ofthe sol
vent. IThe oilv residue isweighed and multiplied
n=l.3998-|-.0'G0242T
by a factor to correct forV the aliquot -portion of Y
_For the production of a fully. refined pi_traiîi11__V wax>
the ethylene dichloride filtrate employed. I The
corrected value Vis the weight perÍ cent of oil inthe '
of commercial grade having an oil content ofless
than 4% lby weight, Vfor example, 1.5%_to 4%.,
' and ' n=l.¿l00_3-{-.00O242T.
" the refractive index-melting point relationship of
In the following table are given the refractive
indices (R. 1.)', melting` points ¿(M. P.)-,- and oil
contents for the sweat stream samples E, F, G, H,
the sweat stream should fall within thevlimits de_
ñned by lines having-the equations
I
I, and J , as well as the melting points, oil con
tents, yields, hardness, and tensile Vstrength »for
And for the production of high tensile strength
the sweated waxes whenthe sweating was stopped
at points I-l, I, and J. The hardness was deter
mined b'y means of Aan instrument known as la
wax 'containing less than about 1.5% of oil, and
preferably less than 1% of. oil, the refractive in
dex-melting point relationship of the sweat '
durometer supplied by the Shore Instrument 75 'stream should fall within the limits defined by
l 2,406,210
5
lines having the equations n=1.3964-}-.O00242T
and n=1.3969+.000242T.
In another aspect of the present invention, it
has been found that the refractive index lof
the sweat stream is, per se, a'valuable guide in
indicating the point at which sweating should be
terminated, particularly in the production ofwaxes of exceedingly low oil content, i. e., less
than about 1% by weight of oil. By determin
4. The method of reducing the oil content of
oily wax, which' comprises subjecting said oily
wax to sweating, and terminating the sweating
of the wax when the relationship betweenk the
refractive index at 176° F. and the melting point
in °F. of a sweat stream sample falls, on a'plot
of refractive index versus melting point, Within
the lines defined by the equations
ing the minimum refractive index of the sweat 10
n=1.3964-|-0.0G0242T
stream and then terminating sweating when such
value is reached, the resulting sweated wax will
and n=l.4003-|-0.000242T, where "n’l’ denotes the
contain little or no oil. Referring to the draw-v
refractive index `and “T” denotes melting point
ing, it will be seen that the minimum refractive
in °F.
.
w
'
index of the sweat stream is reached at a point 15
5. The method of producing> a high tensile
between I and J, and that the oil content of the
wax, which comprises subjecting an oily wax to
sweated wax when the sweating was stopped at
sweating, and terminating the- sweating of the
I was about 1%. By terminating' the sweating
wax when the relationship between the refrac
at the minimum refractive index between I and
tive index at 176° F. and the melting point in
J, a somewhat higher yield of low oil content 20 °F, of a sweat stream sample falls, on a plot of
wax would be obtained than by continuing the
sweating to the point J.
The large scale or commercial sweating oper
refractive index; versus melting point, within
the lines defined by the equations
ations referred to herein may be carried out in
11:1.3‘9644-0000242'1'
the conventional sweating ovens well known to 25
those skilled inthe art, wherein the oily wax
and n=1.3969+0.000242T, ywhere. “n” denotes the
stock is introduced into sweating pansand the
refractive index and “T” denotes melting point
in °F.
’
temperature of the wax then slowly but progres
sively raised to effect sweating and removal of
6. The method' of producing a refined wax,
the sweatable constituents of the Wax.
30 which comprises subjecting an oily wax to sweat
I claim:
ing, and terminating the sweating of the wax
1. The method of sweating oily wax to produce
when the relationship between the refractive in
substantially oil-free wax, which comprises
dex- at 176° F. and the melting point in °F. of a
sweating an oily wax, determining the refractive
sweat stream sample falls, on a plot of refractive
indices and the melting points of successive sam- I index versus melting point, within the lines de
ples of the sweat stream, and terminating the
sweating of the wax when a sweat stream sample
exhibits a melting point higher than that of
the 'preceding sample, and a refractive index at
least as great as that of said preceding sample.
2. The method of reducing the oil content of
in °F.
oily Wax, which comprises subjecting said oily
wax to sweating, and terminating the sweating of
the -wax when the refractive index of the sweat
terminating the sweating of thewax’when the
relationship between the refractive index at 176°
F. and the melting point in °F. of a sweat stream
stream attains a minimum value.
'
3. The method of reducing the oil content of
n=1.398>3+0.000242T, where “n” denotes the re
fractive index and “'I'"` denotes melting point
7. The method of producing scale wax, which
comprises subjecting an oily wax to sweating, and
45 sample falls, von a plot of refractive index versus
melting point, within the lines defined 'by the
oily Wax, which comprises subjecting said oily
wax to sweating, and terminating the sweating
of the wax when the relationship between the re
fractive index at 176° F. and the melting point r50
where f‘n” denotes the refractive index and “T"
in °F. of at least two successive samples of the
denotes melting point in °F.
~
.
sweat stream fall, on a plot of refractive index
versus melting point,‘substantially parallel to the
line represented by the equation
n=1.3950+0.000242T
Where “n” denotes the refractive index and “T”
denotes melting point in 9F.
l
' ï
SEYMOUR W. FERRIS.
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