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Патент USA US2406890

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Sept. 3, 1946.
' A. c. MQHR
' 2,406,890
PRODUCTION OF SULPHUR DIOXIDE
Filèd Feb. `1. _1945
QN
bm.
Nm.
Patented Sept. 3, 1946
" 2,406,390
UNITED STATES VPATENT orifice
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ì
.2,406,890~
PRODUCTION oF sULPrrUR nloxmn
Albert c. Mohr, Arcadis, cam., assigner, by
. mesne assignments, to Chemical Construction
Corporation, New Yorki N. Y., a corporation of‘
Delaware
` A Application February 1, Y1943, Serial No. £114,343
.è claims. (ci. zza-_177)
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This invention relates to the recovery of the
sulphur values present in the sludge or sulphuric
acid residue resulting from the condensation of
olelins with paraiiins in the presence of sulphuric
acid. This condensation is usually termed alky1~
ation and the sulphuric acid body‘removed is
usually termed alkylation sludge. It will be so
referred to here.
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sulphur trioxide, only a limited quantity of water
would form in the converter.
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I have found that none of these proposals for
handling relinery sludge is adaptable‘to alkyl
ation sludge because of the differences `which exist
between this sludge andthe usual refinery sludges
dealt with by Hechenbleikner, Clarke and others.
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To state my empirical ñndings shortly and con
A typical alkylation sludge contains a relatively
cisely, it is necessary to vaporize or atomize the
high percentage of sulphuric acid, usually be 10 alkylation sludge and, while it is >in this con
tween 83% and 90%. The total carbon content
dition, `subject it to such a high temperature
of the sludge is between 5% and 8% With about
that any water ‘present is evaporated and _all
1% of free oil and 4% to 8% unsaturated hydro
' hydrocarbonaceous material present is burned to
carbons. `This `sludge is quite different from the
carbon dioxide and water. To accomplish this,
usual sludge recovered from reñning of petroleum 15 it is necessary to burn additional fuel with the
wherein the relative amounts~ of sulphuric acid
alkylation sludge and this underV conditions that
bodies and carbon bodies are quite different, there `
being usually ’considerably more carbon present
so that the sludge can be readily worked up at
insure complete lburning of the alkylation sludge. '
I have successfully operated by introducing air
into the unit employed for heating and burning
comparatively `low temperatures to give _a coke 20 the alkylation sludge in an amount sufficient to> `
residue, free of acid and having a. comparatively
insure the presence in the gas remaining after
high content of volatile hydrocarbons. A typical process for recovery of the acid and fuel Valdes
from a petroleum reiinery' sludge is described in
the Hechenbleikner Patents 1,953,225 and 1,953,
226. In the former patent, for-example, the acid
sludge isv heated in a rotary kiln by direct con- „
tact with hot combustion gases. In elîect, the
sulphur dioxide present is distilled out of the
combustion of oxygen in excess of ‘that quan
tity of oxygen required to convert the SO2 to
S01.
One of the principal objects of the present in~
vention, therefore, is to provide Va process for the
recovery of the sulphur values in alkylation
sludge as sulphur‘dioxide.
Y
Another object of the invention, and _no less
material at a low temperature to le'ave a dry 30 important,` is to provide a process enabling re
' coke containing so high a content of volatile
covery of the sulphur values in alkylation sludge
_ hydrocarbons that the coke is useful -as 'a fuel.
to be achieved as sulphuric acid.
Because the gases issuing from the Hechen
The invention includes other objects and fea- _
bleikner rotary kiln contain water and various
tures _of advantage, some of which, together with
condensable hydrocarbons in addition to sulphur 35 the foregoing will appear hereinafter. The single
dioxide, it has been proposed to pass this ma
figure in the drawing accompanying and forming
terial `through a secondary hydrocarbon com
a ypart of the following description is a combi
bustion furnaceas ay means of removing the hy
nation'diagram of the combustion chamber and
drocarbons present so that they would be re
‘ a flow sheet of the process employed for recovery
moved instead of burning subsequently in the 40 of the sulphur dioxide values as sulphuric acid.
converters employed to -catalyze the reaction of
sulphur dioxide and oxygen to form sulphur tri
oxide. Thus, Clarke states in Patent 2,019,893 _
' Referring tovv the drawing, the» numeral l0
designates a burner comprising a sh'éll ll con
structed of suitable refractory material, such as
flrebrick, and defining a combustion chamber l2
drocarbons be removed by refrigeration, unless. 45 of preferably cylindrical cross section. Surround
this was practiced with extraordinary care and
ing shell Il is a steel casing I3 acting as 4a pro
With elaborate equipment, complete removal
tective reinforcement. The outside of the steel
could not be secured. As a consequence,A water
shell Ais preferably covered with suitable heat in
would form in the converters and would 'make
sulating material Il.
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diiiicult the subsequent condensation of the sul 5.0 At one end of the reaction chamber .l2 and
phur trioxide. Clarke proposed limited burning
preferably centrally'thereof is provided an alkyl
of the hydrocarbons in the gases -removed from
ation sludge atomizing and injecting device l5
the` rotary kilns so that, upon the subsequent
for discharging a mixture of atomized sludge
addition of the necessary quantity of air re
and air -into the reaction chamber I2.- Placed
quired for conversion of the sulphur dioxide to
about the alkylation sludge atomizing device I5
‘ that’ while Hechenbleikner suggested these hy
2,466,890
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are a plurality of fuel burning devices I6. These
are placed as a ring about the alkylation sludge
atomizing device I5 so that the flame path from
each burner I6 is directed into the stream is
suing from the alkylation sludge atomizing
device.
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is removed. The gases then pass on through pipe
24 to a ñlter 25 wherein mechanically entrained
solid material and suspended droplets of sul
phurìc acid are removed. The filtered gas is then
passed through pipe 21 into a drying tower 28
where the gases are brought into contact with
high strength sulphuric acid to reduce the water
At the `other end of the combination cham
contentto that quantity essentlaldîor good oper
ber I2 several ïtiers of checkerwork, ‘usually made
ation of the sulphur dioxide conversion unit.
of refractory brick, are provided. These `serve
several'purposes. First, they act as a means for 10 The gases are Withdrawn through pipe 29 by
blower 3l -and are forced on' through a pipe 32
radiating heat back into the combustion chamber
into a ñrst heat exchanger 33. From this-they
to insure that the temperature therein is main
pass through pipe 34 into a second heat ex
. tained suii‘iciently high so that the atomized
changer 36. In each heat exchanger, as will be
sludge is subject to an adequately high temper
presently explained, the gases are heated by heat
ature and is quickly brought up to' that point
exchange with the gases issuing from the con
Whereat hydrocarbonaceous materials present are
verters employed. The hot dry gases then pass
transformed to carbon dioxide and water. Sec
through pipe 31 through the first converter 38
ond, the checkerwork brick lserve as a support
wherein at least a portion of the SO2 present
for suitable catalytic material for furthering the
combustion of carbon and hydrogen in the fuel 20 is caused, because of the presence of the catalyst
in the converter, to react with the oxygen pres
and in the sludge before the gases pass out
through outlet I8.
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ent and form sulphur trioxide.
From the con
verter the gases pass through pipe 39 through
the heat exchanger 36 to heat gases passing
erably made cylindrical in shape and compara
tively of large capacity so that gases have ade 25 therethrough, then on through pipe 4| to the
second converter 42. From this gas`es now free
quate residence time in the combustion chamber.
of SO2 and containing sulphur only in the form
In one successful plant Iemployed a combustion
of sulphur trioxide, pass through pipe 43 into the
chamber 12 feet in diameter and 25 feet in overallA
heat exchanger 33, from which they pass through
length. This handled 8,000 pounds of alkylation
sludge per hour. The furnace volume should be 30 pipe 44 to the absorbing tower 46 wherein the
sulphur trioxide is taken up by water to form
comparatively large for the weight of the sludge
sulphuric acid.
handled to insure ample residence time. In the
As a speciiic operation illustrative of the prac
specific> example the furnace volume is 35 cubic
tice of this invention the following is set forth.
feet per hundred' pounds of sludge per hour. This
can be lowered to 15 cubic feet or increased, al 35 An alkylation sludge was employed containing
87% H2504, 6.5% carbon, 1% hydrogen, 3% wa
though,if this is done the chamber size becomes
ter, and about half of 1% free oil and a consid
uneconomical, and 50 cubic feet is usually a max
erable quantity of dissolved sulphur dioxide. I
imum.
injected 8.000 pounds of the sludge per hour to
The fuel and alkylation sludge supplied are _
mixed with sufiicient air to insure that all car 40 gether with 6,700 cubic feet of refinery waste
gases. Burning of the waste gases resulted in
bon, hydrogen and sulphur in the gases issuing
the sludge being consumed in the combustion
through the exit I8 are respectively converted
chamber I0 vat a temperature maintained be
to 4carbon dioxide, water and sulphur dioxide. To
tween 1500° and 1800" F., suñìc’ient air being sup
secure this, the necessary quantities of excess air
are added, taking into account the composition 46 plied to insure the carbon present was converted
to carbon dioxide, the sulphur present was all in
of the fuel burned and the alkylation sludge.
the form of sulphur dioxide while all hydrogen
Usually the quantity of air introduced is such
In practice, the combustion chamber I2 is pref
that oxygen need not be supplied upon the con
version of the sulphur dioxide to'sulphur trioxide.
present was oxidized to form Water., The com
bustion gases formed Were passed through the
As a suitable fuel I have successfully employed 50 apparatus previously described, being reduced in
temperature to '15 degrees F. as they issued from
refinery waste gases although one can use oil,
natural gas, sulphur or hydrogen sulphide. Usu
the filter 26 and having a water content of only
ally, however, sulphur will not have sufficiently
8 milligrams of water per cubic foot as gases
high heat imparting capacity to suñice alone and.
passed from the drying tower 28 through pipe
while it can be used as supplementary fuel and 55 29 into the conversion unit.
to provide a gas rich in sulphur dioxide, usually
Since the present invention is not concerned
some quantity o_f oil or other fuel will have to be
with the details of mechanical construction, the
burned. Hydrogen sulphide alone will supply
drawing is really more in the nature of a ñow
suiiicient heat, usually one part by weight of hy
sheet. It should be understood, of course, that
drogen sulphide to two parts of alkylation sludge. 60 various modifications in equipment and arrange
Before the gases are passed to the sulphuric
ment` may be necessary to meet the particular
acid plant, I remove substantially all water. This
conditions in different plants and these are in
is accomplished by passing the gases, preferably
cluded in the invention. For example, instart
through a waste heat boiler, pipe I9 leading from
exit I8 passing to waste heat boiler 2 I. Here the 65 ing up such plants auxiliary heat must be pro
vided, because the temperature is insufficient to
gases are cooled down to a considerable extent,
permit the catalytic oxidation of sulphur diox
depending upon ,the heat economy desired. The
ide to commence unless the bodies of catalytic
partiallyA cooled gases then pass through pipe
materials in the converter are brought up to tem
22 to a cooling tower 23 where the gases are fur
ther lowered in temperature, preferably by bring 70 perature. A suitable starting furnace will enable
this to be achieved. It is, therefore, essential but,
ing them into direct contact with a cold water .
since it forms no part of the present invention,
spray. If one cooling tower does not sufñce, an
neither it nor the various valves nor the other
other or additional cooling means may be pro
control mechanisms, pumps. etc., are shown,
vided. In any case, the gases are lowered to a
temperature whereat most of the water present 75 these being readily provided by those skilled in
2,406,890
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the art in view' of the foregoing adequate dis
closure.-
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lytic material _promoting combustion of carbon
and hydrogen with oxygen, said process compris
In connection with the catalytic material car
ing burning a fuel withexcess airV in said com
ried by the checkerwork l1, I preferably employ
materials which will promote the combustion of
carbon and hydrogen to carbon dioxide and wa
ter although the extended surface of the check
erwork acts in part in this way. Such catalysts
bustion> chamber to heat said extensive surface
and said brick checkerwork and to supply radiant
heat to said chamber at a temperature of above
1500° F., spraying the sludge into said combus
tion chamber to evaporate water therefrom and
are, for example, metal salts such as a 0011961’
burn with said excess air substantially all carbon, .
gen, said process comprising burning a fuel with
excess air in said combustion chamber to heat
said extensive surface and said brick checken.V
work and to supply radiant heat to said chamber
at a temperature of above 1500*’ F., spraying the 25
must pass, said process comprising burning a fuel
with excess air in said combustion chamber to
heat said extensive surface and said brick check
hydrogen and sulphur compounds respectively
salt and other metals. .These _catalysts are well
to carbon dioxide, water, and sulphur dioxide and
known as is the impregnation of the brick.
_ ' passing the resulting gases through said checker
I claim:
` Work to ensure completion of the carbon and hy
1. A process for ‘converting an alkylatibn sludge
containing sulphuric acid and sulphur compounds
drogen oxidation.
`
4. A process for converting sludge containing
to sulphur dioxide in a combustion chamber hav 15
hydrocarbonaceous material, sulphuric acid and
ing an extensive internal surface and brick check
sulphur compounds to sulphur dioxide in acom
erwork at one end thereof through which gases
bustion chamber having an extensive internal
issuing from the chamber must pass, said check
surface and brick checkerwork at one end thereof
erwork bricii- carrying catalytic material promot
through which gases issuing from the chamber
ing combustion of carbon and hydrogen with oxy
sludge into said combustion chamber to evaporate
erwork and to supply radiant heat to said cham- ' -
ber at a temperature of above 1500° F., spraying
l the sludge into said combustion chamber to evap
Water thereform and burn with said excess air
orate water therefrom and burn with said excess
air substantially all carbon, hydrogen and sulphur
substantially all carbon, hydrogen and sulphur
compounds respectively to carbon dioxide, water,
and sulphur dioxide, passing the resulting gases
through said checkerwork to ensure completion
of the carbon and _hydrogen oxidation, cooling the
compounds respectively to carbon dioxide, water,
and sulphur-dioxide, passing the resulting gases
through said checkerwork to ensure completion
of the carbon and hydrogen oxidation, cooling
gases issuing from -said furnace after passage
through said checkerwork to condense the major
the gases issuing from said furnaceafter `passage
through said checkerwork to condense the major
‘ portion of water in said gases, separating said 35 Portion of water in said gases, separating said
condensed water and drying the remaining gases
with concentrated sulphuric acid to remove sub
stantially all the water therefrom.
2. A process for converting sludge containing
condensed water and drying the remaining gases
with concentrated sulphuric acid to remove sub
stantialiy all the water therefrom.
5. A process forconverting sludge containing
hydrocarbonaceous material, sulphuric acid and 40 hydrocarbonaceous material, sulphuric acid and
sulphur compounds to sulphur dioxide in a com- \ sulphur compounds to sulphur dioxide `in a com
bustion chamber having an extensive internal sur
bustion chamber having an extensive internal
face and _brick checkerwork at one end thereof
surface and brick checkerwork at one end thereof
through which gases issuing from the chamber
through which gases issuing from the chamber
must pass, said checkerwork brick carrying cata
must pass, said process comprising burning a fuel
lytic material promoting combustion of carbon 45 with excess air in said combustion chamber to
andhydrogen with oxygen, said‘process compris
`heat said “extensive surface and said brick check
ing burning a fuel with excess air in said com
erwork and to supply radiant heat to said cham
bustion chamber to heat saidI extensive surface
ber at a temperature of above 1500“ F., spraying
and said brick checkerwork and to supply radiant
the sludge into said combustion chamber to evap
heat to said chamber at a temperature of above 50 orate water therefrom and burn with said excess
1500° F., spraying the sludge into said combustion
chamber to evaporate water therefrom and burn
with said excess air substantially all carbon, hy
air substantially all carbon, hydrogen and sul- '
phur compounds respectively to carbon dioxide,
water, and sulphur dioxide and passing the re
sulting gases through said checkerwork to ensure
drogen and sulphur compounds respectively to _
carbon dioxide-water, and sulphur dioxide, pass 55 completion 'of the carbon and hydrogen oxidation.
ing the resulting gases through said checkerwork
6. A process for converting an alkylation sludge
to ensure completion ofthe carbon and hydrogen
containing sulphuric acid into gases'containing
sulphur dioxide which comprises burning'gaseous
oxidation., cooling> the gases issuing from- said
furnace after passage through said checkerwork
fuel inthe presence of excess air lin a combustion
to~condense the major portion of water in said 60 chamber. preceding and heating an extensive
gases, separating said condensed water and dry
course of checkerwork in the furnace so as to ing the remaining gases with concentrated sul
maintain a temperature above 1500“ F.. in saidv
phuric acid to remove substantially all the water ~ chamber spraying the strong alkylation acid
- sludge into `the name of combustion, and then
3. A process for converting sludge containing 65 passing the resulting >gases through said checker
therefrom.
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hydrocarbonaceous material, sulphuric acid and
sulphur-compounds to sulphur dioxide ina com
bustion chamber having an extensive internal
_ work, the excess of air beingsuflicient to burn
_ the carbonaceous matter in said sludge but insuf
iicient to dilute the S0: content of the gaseous
surface and brick checkerwork at one endl thereof.
„ >_products below the content suitable for use in the
through which gases issuing from the _chamber 70 sulphuric acid contact process. .
must pass, said checkerwork brick carrying cata
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ALBERT C. MOHR.
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