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Dec; 13, 1949
'
F. |_. SYMONDS
'
2,490,936
PROCESS OF PRODUCING OXYGEN
.
Filed April 18, 1945
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Dec. 13, 1949
2,490,986
F. L. SYMONDS'
PROCESS OF PRODUCING OXYGEN
Filed April 18, 1945
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Fred L. Symona's v
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?fforney
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Pntented Dec. 13, 1949
2,490,986
‘UNITED s'rA'rEs PATENT OFFICE
PROCESS OF PRODUCING OXYGEN
Fred L. Symonds, Whiting, Ind., eselgnor to
Standard Oil Company, Chicago, Ill".00!"
poration of Indiana
Application April 18, 1945, Serial No. 588,981
5 Claims. (Cl. 23-221)
2
1
This invention relates to an apparatus for con
ducting chemical reactions in the gas phase in
wall construction providing for transfer of ?uid
the presence of ?nely divided, ?uidized solids.
Figure 7 is a flow diagram illustrating the use
of the furnace, shown in plan, in a‘ process of
separating oxygen from air, accessories shown in
The solids may act as catalysts to accelerate a
chemical reaction involving one or more gases
or vapors, or the solids may take part in the
reaction by supplying certain chemical sub
stances thereto, or by abstracting chemical sub
stances therefrom. The invention relates also
to gas phase reactions conducted at pressures
approximating atmospheric pressure, and still
more particularly to a process in which powdered
solids are contacted with gases in two or more
ized solids;
Y
schematic elevation;
Figure 8 is a. plan view of an alternative fur-_
nace construction; and
Figure 9 is a modified solids transfer lift.
Referring to Figure 1, showing the rectangular
form of furnace, two reaction sections are pro
vided, No. 1 and No. 2, with a dividing wall I!
in between. The wall is provided with ‘transfer
lifts II and I! for powdered solids. Aeration
stages in series.
gas, for example steam, nitrogen, etc., is supplied
One object of the invention is to provide an
to the lifts by pipes l3 and I4.
apparatus for conducting gas phase chemical re
Referring to Figure 3, the construction of the
actions in stages wherein large volumes of ?uid
furnace floor is shown in some detail. Above a
ized solids are maintained at elevated tempera
concrete slab llthere is supported a false floor
ture in suspension in the gases undergoing
reaction. Other objects of the invention in 20 It or hearth constructed of open joint tile, brick,
or preferably porous plate, fritted porcelain or
clude the following: To provide an apparatus
silica ware, refractory at the temperatures em
for transferring large volumes of ?uidized solids
ployed in the furnace but su?iciently porous to
thru a series of separate reaction stages in a
permit the up?ow of gases therethrough. Be
multistage process with a minimum expenditure
neath the floor I‘ are gas ducts I‘! to which are
of energy, minimum cost, and substantially no
connected reaction gas induction lines l8 and
pressure differential between the stages; to pro
It by tuyeres 2.. Cooling may be supplied to
vide an apparatus for uniformly contacting gases
the furnace by injection of .water thru a plu- >
with fluidized solids at relatively low gas velocity
rality of water lines 2| extending into the fur
and low pressure differentials between incoming
and outgoing gases; to provide an apparatus for 30 nace. These mayeffect cooling by indirect con
duction of heat as in the case of a water coil
contacting gases with ?uidized solids wherein
heat exchanger. Where a large amount of cool
the temperature of the contacting mass is con
ing is needed the water lines 2| may be perfo
trolled by radiation; to provide a process of sep
rated to supply a water spray to the furnace.
arating oxygen from air by contacting with ?uid
It is preferred to construct the furnace with
ized solids in a low pressure system and to pro
horizontal roof 22 to provide a uniform distri
vide a furnace for conducting gaseous reactions
bution of radiant heat from the roof of the fur
in the presence of ?uidized solids at high tem
nace downward against the ?uidized solids mov
perature in which the ?uidized solid is retained
ing across the furnace ?oor. Radiation between
as a relatively shallow layer, thus avoiding de
struction of the apparatus by the movement of 40 the bed of solids and the roof may be in either
direction from hearth to roof or vice versa, de
deep masses of ?uidized solids. ,
pending on whether the solids are being heated
The invention is illustrated by drawings in
or cooled. The roof may be cooled by a water
which:
spray within the reaction chamber or by other
Figure 1 is a plan view of the contacting appa
means where cooling is desired, or it may be
ratus;
‘
heated by a ?ame or by other means when it
Figure 2 is an elevational view of the same
is desired to radiantly heat the solids in the bed
apparatus;
'
on hearth I‘. It is preferred that the roof be
Figure 3 is a sectional view of the apparatus
substantially co-extensive with the hearth and it
showing construction details;
is important that the distance between the roof
Figure 4 shows the ?oor construction detail;
and the hearth be relatively short, depending
Figure 5 is a.sectional detail showing one form
upon the size ‘of the furnace. The distance
of wall construction with provision forfiuidized
should not be greater than one-half the square
solids transfer between stages;
root of the internal area of the roof and it is
Figure 6 is a section of a modi?ed separator 55 preferred that it be from one-quarter to one
2,4909”
tenth the square root of the internal roof area.
The walls and roof of the furnace are con
structedof suitable refractory material such as -
flrebrick, magnesite brick, asbestos, etc.
The porous ?oor construction is shown in
greater detail in Figure 4 which illustrates a
suitable arrangement for attaching and holding
4
a minimum of dispersion of the solids in the gas
phase space of the section to which they are trans
ferred. As indicated in Figure 5, the ?oor tiles
8‘ directly below the openings into the transfer
lifts 32 may, if desired, be impervious to gases to
prevent gases charged to the reaction zone from
‘ rising into the transfer lifts with the solids. The
in place the porous tilesvor plates It. In this
only gases transferred with the solids are there
construction, bolt 23 imbedded in concrete base
fore the aeration gas supplied thru nozzles 33
ll serves to hold the porcelain washer 24 down 10 and the gas occluded in the solids from the re~
on the tiles It. Porcelain or tile support 15 is
action section.
suitably made in the form of a cylinder on which
If it is desired to remove occluded gases from
the corners of four adjoining tiles are rested.
the powdered solids passing from section to sec
Connections for withdrawing gases from the
tion. this may be accomplished by supplying solids
furnace are indicated by headers 28 and 27 in 15 to lifts II and if by short dowricomers into which
Figure 2. In this ?gure, the header 25 is the
the solids are subjected to inert stripping gas, for
gas outlet from reaction section 5 while 21 con
example steam. However, it is generally not nec
ducts the gas away from reaction section 2. Wall
essary to resort to this expedient.
and roof supports are indicated at 28.
In Figure 6 is shown a simpli?ed lift arrange
Referring again to Figure l, the ?uidized solids
ment in which the dividing wall i0 between sec
maintained in turbulent motion by gases ?owing
tions is provided with an opening or series of ports
upwardly therethrough from the porous door of
I‘! at the bottom, and opposite the ports a weir
the furnace form a shallow pool, the depth of
ll over which the fluidized solids are lifted by
which is usually maintained at about 2 to 4 feet,
aeration gas injected thru line l3. Aeration line
more or less, depending on the reaction employed. 25 li'may be a horizontal pipe line in the bottom
As rapidly as solids are transferred thru the divid
ofthe lift space 39 included between the wall It
ing wall between the reaction zones I and 2 in
and baffle 38 and aeration gas may be injected
one direction, an equal amount of solids are trans
thru suitable nozzles fitted in line l3.
ferred in the reverse direction following the ar
An alternative arrangement of furnace is shown
rows. The center ba?ie plate 28 serves to direct 30 in Figure 8 in which the plan of the furnace is
the flow of solids in a generally elliptical path to
circular instead of rectangular and the ?uidized
avoid short circuiting between the transfer lifts
solids pursue a circular course from section to
II and i2. It should be understood that the
section. Four sections are illustrated as indicated
wall It) may be in any suitable position dividing
on the drawing, the fluidized solids flowing under
the furnace into sections of equal size or unequal
dividing walls 40, 4!. 42 and 43 as indicated by
size as indicated, where the difference in reaction
the arrows. Just as in the case of the rectangular
velocities requires a longer time of contact in
furnace shown in Figure l, the reacting gases
one reaction zone than in the other. Reaction
are injected thru the porous floor of each section
gas or vapor is supplied to reaction section 2 by
and withdrawn from a higher point therein. The
line 30 with connections leading to the subfloor 40 application of the furnace shown in Figure 8 to
ducts beneath this section. For most operations,
a process of abstracting oxygen from air will be
the level of the ?uidized solid pool on each size
described hereinafter.
of the wall it) is about the‘ same with the same
There are many applications of my improved
pressure, usually atmospheric, in each section of
?uidized solid contacting furnace to industrial
the furnace.
processes including such processes as the conver~
A detail showing the construction of a suitable
sion of hydrocarbons, the cracking of hydrocarbon
transfer lift H is shown in Figure 5 wherein the
oils, the puri?cation of gases, reduction of ?uid
dividing wall i0 may be of reinforced concrete
ized ores, manufacture of water gas, the prepara
construction, provided with a port 3| to which
ticn of synthesis gas for the Fischer process by
is connected lift tube 32. Tube 32 is of suitable (A) conversion of methane with metal oxides into
refractory material such as porcelain or ceramic
ware, or it may be of metal resistant to heat and.
carbon monoxide and hydrogen, etc. Following
horizontally or downwardly as indicated, there is
ploying manganites, have been unable to compete
is a description of the application of this ap
corrosion, for example Chromel, calite or duriron.
paratus to the recovery of oxygen from air.
Aeration gas from supply line i3 is introduced
The process is especially applicable to making
thru a suitable nozzle 33 into the dependent open . . oxygen, particularly to the manufacture of in
end of transfer lift 32. Bolts 34 employed in at
dustrial oxygen where high purity is not required
taching the transfer lift to the dividing wall may
and where the oxygen concentration in the prod
be protected from heat and corrosion by asbestos '
uct gas may vary from about 75 to 95 per cent.
cement covers 35.
The use of my ?uid ?ow furnace offers a method
It should be understood that the body of the 60 for making industrial oxygen more cheaply than
furnace is preferably constructed of steel plates
has been possible heretofore. Thru the agency
with gas-tight joints with provision for expansion
of a metal oxide, or other agent existing in two
and contraction of the refractory lining therein.
states of oxidation capable of acting as an oxygen
The gas phase zones of the separate reaction sec
carrier between two stages at different tempera
tions are completely separated and gas is effec
tures, a regeneration stage and a decomposition
tively prevented from passing from zone to zone
stage, it is possible to operate an oxygen process
by the ?uidized solids transfer lifts 32 which ex
with my furnace in a continuous uninterrupted
tend nearly to the floor of each section and the
manner with accurate control of temperature and
openings 3| in dividing wall I0 are thereby sealed
without the necessity of indirectly applying heat
by the pools of ?uidized solids in their respective 70 to either the oxide regeneration stage or the oxide
zones. Aeration supplied to the ?uidized solids
decomposition stage.
in lifts 32 reduces the density locally within the
Previous chemical processes for the manufac
lift causing the solids to rise and flow over thru
ture of oxygen, such as the Brin process employ
the opening 3|. By directing the stream of solids
ing barium oxides and the du Motay process em
0,400,901:
5
with the liquid air process because of several in
herent di?lculties, one important difllculty being
the intermittent operation with lack of proper
temperature control and heat balance between
the various stages of the process. I have now
discovered that these difficulties encountered with
the oxide process can be overcome when employ-'
ing the oxide in the form of a ?uidized turbulent
mass in the furnace hereinabove described and
continuously recycling the dense ?uidized mass
as a pseudo liquid stream between two stages of
oxidation. By this means I have found it possible
to control the operation with far greater accu
racy than has heretofore been possible, and as a
result the state of oxidation of the metal oxide is
more uniformly regulated, giving greater produc
tion of oxygen. I have also found that the decom
posing stage, or lower stage of oxidation, can be
maintained at a higher temperature by the simple
expedient of introducing a controlled amount of a
combustible gas therein.
Application of the improved contacting method
the regeneration temperature may be about 300
to 450° C., preferably about 400° 0.
Oxygen liberated by the increased temperature
of the decomposition zone 50 is withdrawn from
the vapor space thereof by line ‘H leading to
cyclone separator ‘I! wherein entrained solids are
removed and returned by line ‘I3 to the decompo
sition section. The oxygen admixed with com
bustion products from‘ the heating gas supplied
10 by line ‘I. is conducted by line 14 to scrubber ‘l5,
thence by line 16 to the second scrubbing stage
11. Solids separated in the scrubbers are con
veyed by water which is introduced thru line 18
to scrubber ‘l1 thence by line 19 to scrubber ‘l5
and thence by line all back to regeneration zone
5| wherein the water is evaporated and the solids
are returned to the furnace.
Steam resulting from the combustion in sec
tion 50 is largely condensed in the scrubbers 15
and ‘I1 and the remaining oxygen is led by line 8|
‘to-condenser tower 82 where it is further cooled,
preferably by refrigerator coils, to remove the re
maining water and provide substantially dry oxy
gen to the outlet l3, condensed water being dis
to oxygen manufacture is illustrated in Figure 7
which shows schematically in plan section, a rec
tangular furnace similar to that shown in Figure 25 charged by line 84.
1 to which is connected accessory apparatus shown
Where the heating gas supplied by line 10 is a
in elevation for handling the gaseous products
hydrocarbon gas or one containing carbon com
from the furnace. Referring to the drawing, 50 is
pounds, e. g. water gas, the oxygen produced will
the decomposing section of the furnace and 5| the
contain from 5 to 25- per cent of CO2. This may
regeneration section, ?uidized solids being cir 30 be removed by any suitable COz-absorbing system
culated between the two sections thru dividing
such as the alkali carbonate system, triethanol
wall 52 as indicated by the arrows.
Steam for
the transfer lifts is provided by lines 53 and 54.
Regeneration air is supplied to section Si by
blower 55 and conduit 56, leading the air beneath
the porous ?oor of the regeneration section.
Spent regeneration gas consisting largely of ni
amine, or other suitable process. For some pur
poses the oxygen may be employed without re
moval of CO2, for example in the smelting of ores,
re?ning of steel, and in the Fischer process for
preparing synthesis gas. In the latter reaction,
the oxygen is used to maintain the temperature
trogen and some unused oxygen is conducted by
of the gas maker in the water gas temperature
line 51 to cyclone separator 58 wherein most of
range, e. g. 1700 to 2200° F., and any CO2 con
the entrained powdered solid oxygen carrier-is 40 tained in the oxygen is converted to CO by the
recovered and returned to the regenerator by line
fuel employed be it coke, methane, or other suit
as.
able carbonaceous material.
The remaining nitrogenous gas from separator
Where a supply of hydrogen is available it may
58 is conducted by line 60 to water scrubber Bl
be employed as the heating gas in zone 50 thereby
where remaining oxygen carrier is recovered from
producing only water on combustion in the de
the gases. A second scrubbing stage is shown at
composition zone, making it unnecessary to sup
82, the gases being conducted from El to 62 by
ply a carbon dioxide removal step in the process.
line 63. The spent gases are withdrawn by line
A suitable source of hydrogen for the purpose is
64 and exhauster 65. .Water supplied by line 66
an adjacent electrolytic hydrogen-oxygen plant.
to scrubber 62 is conducted with any solids ac
The oxygen produced in the electrolytic plant may
cumulated therein to the ?rst scrubbing stage 6i,
be combined with the oxygen produced in the
transfer line 61 being provided for the purpose.
chemical process Just described. Regardless of‘
The slurry of recovered solids and water is re
what heating gas is used, it is preferred to use a
turned to the regeneration zone of the oxygen
gas substantially free of nitrogen so that the oxy
furnace by line 88 and pump 69. In the regenera
gen produced in the process will not be contami
tion zone 5 I, the slurry is evaporated by the excess
heat therein and simultaneously serves the useful
purpose of reducing the temperature in the re
generation stage.
'
hated with excessive amounts of nitrogen. Nat
ural gas, refinery gas, water gas or the tail gas
from a synthol process may be employed. The
gas may be preheated to a high temperature, e. g.
Regenerated oxygen carrier from 5| is heated 60 500 to 1000‘? F., before introducing it into the de
to a higher temperature in section 50 by any suit
composer, heatfor the purpose being obtained
able means but preferably ' by the injection of
largely by heat exchange with hot products with
combustible gas thru line 10 leading to the sub
drawn from the regenerator and/or the decom
?oor space below section 50, the gas being evenly
D0581‘.
distributed throughout the mass of ?owing, tur 65 In the decom'poser 50, the oxygen carrier lib
bulent ?uidized solid oxygen carrier by the porous
erates oxygen at‘ the higher temperature prevail
gas-permeable ?oor hereinbefore described. The
ing therein and the liberation of oxygen is as
amount of gas supplied is just suilicient to-con
sisted by dilution with steam or other gases, par
sume a portion of the oxygen of the heat carrier
ticularly the decomposition products, steam and
and provide as a. result of the combustion the 70 CO2, resulting from the combustion of the heat
amount of heat necessary to raise the tempera
ture of the decomposition zone to the desired de
composition point. In a typical operation, the de
composition temperature may be about 500 to 600°
ing gas introduced by line 10.
In a typical operation of my process, I may
maintain the ‘temperature of the regenerator at
about 400° C., employing for the oxygen carrier
C. and preferably about 550° C. Simultaneously 76 calcium manganite preferably deposited on a
2,490,0ao
suitable carrier such- as silica gel, clay, bauxite,
diatomaceous earth, aluminum oxide, magnesia
or an acid-treated clay such as Super Filtrol.
The regenerated or reoxidized carrier is then
conducted to the decomposer where it is heated
to about 600° C. as hereinabove described, at
which temperature oxygen is liberated and the
calcium manganite is reduced to a lower state of
oxidation, in which form it is recycled to the re
8
.
avoid dilution of the air in the fluidized} solids in
the regenerator with the steam thus produced,
I can inject the water into the gas space in‘the
regenerator, thus cooling the bed of solids indi-.
rectly by radiation as indicated hereinabove. The
steam resulting from the vaporization of cooling
water together with the residual nitrogen of the
air charged to the regenerator is conducted from
the regenerator by line 26 leading to a stack for
producing natural draft to assist in operation of
the regenerator.
Referring again to Figure 8 previously dis
cussed, the circular furnace shown in sectional
plan view is provided with four sections instead
ture of the hot oxygen carrier ?owing from 50 to 15 of two as in the case of the furnace described In
SI may also be reduced by passing it over in
Figure i. In section I, the regenerating zone.
direct heat exchanger coils in the regenerator and
the oxygen carrier is oxidized to a higher state
the heat obtained in this way may be employed
of oxidation by air injected below the porous
for generating steam or for other purposes.
?oor of the furnace, air being supplied by blovier
Another oxygen carrier which may be used in
85 thru duct 86 and denuded air consisting lsf'g'e
the process is calcium plumbate, preferably in
ly of nitrogen and about 2 to 10 per cent of oxy
admixture with manganese oxide and supported
gen is discharged to the ?ue by line I‘l connected
generator I2 wherein its temperature is again
reduced to about 400° C., by water evaporation
and cold regeneration air in which condition it
is capable of absorbing additional oxygen from
the air introduced by blower 55. The tempera
on a suitable, ?nely divided solid. Manganese
to the gas space in section I.
oxides promoted with copper oxides may be em
From section I the ?uidized solids ?ow thru
ployed at temperatures of 1000 to 1200° C. for the 25 dividing wall 40 into section 2 in which the tem
regeneration and disengaging stages, respectively.
Catalysts may also be used. Certain other oxy
gen carriers may be employed, particularly the
alkali metal manganites and plumbites and
perature is raised by the introduction of a fuel
gas, e. g. methane, by line 8! connecting to ‘the
sub?oor space below the ?uidized solids bed.. At
the higher temperature, e. g. 550° (L, the oxygen
barium oxide, if the operation is conducted with 30 is disengaged and discharged by line 89. ‘Sulli
exclusion of CO: from the decomposer and re
cient lime or other suitable oxide is employed with
generator. In order to operate satisfactorily with
the oxygen carrier in ?uidized finely divided form
these oxygen carriers, it is necessary to carefully
to absorb in section 2 carbon dioxide producedin
scrub the air employed in the regenerator to re
the combustion of the heating gas, calcium car
move CO2, and it is not possible to employ car
bonate being formed by the carbonation of the
bonaceous gas for internally heating the decom
poser. In that case, if hydrogen free of carbon
compounds is not available for the purpose, it is
necessary to supply heat to the decomposer in
lime. The oxygen discharged thru line I! is ac
directly.
This can be accomplished by circulat- -
cordingly substantially free of carbon dioxide
and for most processes will require no further-de
carbonation.
The ?uidized solid oxygen carrier and calcium
ing the ?uidized solids in the: decomposer thru a
carbonate are now conducted to section 3 where
tubular furnace, not shown, indirectly heated to
obtain the desired temperature.
In the operation of the furnace, the ?uidized
in the temperature is still further increased, e. g.
to 500 to 1000° C., as a result of the combustion of
additional fuelgas supplied by line 90 interact
solids oxygen carrier may suitably have a density 45 ing with air supplied by line 9|. At the higher
temperature obtained in section 3, the lime is
of about 50 pounds per cubic foot when aerated
in the furnace'by an up?ow gas stream moving
calcined, regenerating calcium oxide and dis
with a vertical velocity of about four feet per
charging CO: to the ?ue by line 92. Combustion
gas and air may be mixed in a suitable burner
second. In the transfer lifts from wall 52, the
before injecting into the sub?oor space in sec
density of the ?uidized solid oxygen carrier may
suitably be reduced to about 20 to 30 pounds per
tion 8, the heated combustion products passing
upwardly thru the layer of ?uidized solids and the
cubic foot by additional aeration as indicated.
?ue gas being discarded from the gas space in
Pressure in the furnace is suitably about 1 to 5
section 3 byline 92.
p. s. i. gage in each section.
The oxygen carrier, suitably calcium manganite 55 The calcined mixture of oxygen carrier and
in the form of a powder, may have a. particle size
lime is next cooled in section 4 by a water spray
or by indirect cooling, the temperature being again corresponding to 20 mesh and ?ner, i. e. 50 to 200
mesh. Still finer material may be employed of
returned to 300 or 400° C. before returning the
the order of 300 to 400 mesh but if too ?ne, pro
oxygen carrier and lime thru dividing wall 43
vision must be made for recovering the oxygen 00 into section I for recharging with oxygen.
carrier from the gases in addition to simple set
The ?uidized solids transfer lift zone in Figure A
tling or cyclone separation. The density of the
9 is a modi?cation of that shown in Figure 6 pre
oxygen carrier suspension when in operation will
viously described. Its operation diil'ers in that
vary greatly with the nature thereof but it will
the dividing wall 93 is located on the out?ow
usually be about 25 to 100 pounds per cubic foot 05 side of the bail‘le 94, whereas in Figure 6 the divid
depending on the specific material employed, its
ing wall I II is on the inlet side of the space de?ned
particle size, and the air velocity employed in the
between the wall I0 and baffle 30. Aeration gas
regenerator. The ?uidized suspension forms
supplied by perforated pipe 95 serves to re-v
within the regenerator a pseudo liquid layer, the
duce the density of the ?uidized solids
depth of which is preferably maintained at about 70 in the space between the bafile 94 and ?oat
3 to 5 feet.
Inasmuch as the regenerator nor
mally must be cooled, this may be accomplished
by injecting regulated amounts of water by line
2| (Figures 1 and 3), the resulting steam passing
oil with the nitrogen thru line 28. In order to 75
ing baffle 88, forming a chimney within which
the ?uidized solids rise to an elevation above
the level of the ?uidized bed 91. Aeration gas
escapes from the solids at the surface 90 allow
ing the ?uidized solids which spill over baille ll
10
to flow by gravity under wall 93 into the adjacent
in which a gas is contacted with a ?uidized solid
chamber 99. With this form of transfer lift,
there is less danger of escape of gas from the gas
phase of one section to the gasephase of thead
jacent section under dividing wall 93 for the
reason that the ?uidized solids bed level is higher
at the dividing wall than the average‘ level of
contact agent, catalyst or chemical reagent. In
my copending application, Serial No. 613,792, ?led
August 31, 1945, I have shown a method of mak
ing feed gas for the Fischer process, using ?uid
ized solids as oxygen carriers.
The scope of the
invention is described by the following claims:
the fluidized bed in the adjoining chambers. -
I claim:
'
As hereinabove indicated, oxygen made by my
process is particularly advantageous for use in
the Fischer process of hydrocarbon synthesis.
Carbon dioxide which it contains as a result of
the combustion reaction in the metal oxide de
composition stage can be reduced to carbon
monoxide at water gas temperatures in the gas
preparation step for Fischer synthesis. In carry
ing out this procedure, the oxygen from the’ de
composition zone containing from 10 to 50 per
pension by the up?owing stream of air passing
therethrough, discharging nitrogen from said
regeneration zone, transferring the regenerated
cent of CO2 and a small amount of nitrogen, e. g.
oxygen carrier to a decomposing zone wherein it
1. The process of producing commercial oxygen
from air which comprises iniecting air into a
regenerator at a low point in contact with a
iiuidized solid oxygen carrier comprised of a dis
sociable oxygen compound of a metal of variable
state of oxidation, said carrier being maintained
at unil'orm temperature and in dense phase sus
5 to 15 per cent, is conducted preferably while hot 20 is maintained in fluidized dense phase turbulent
suspension by an upriowing stream 01' disengag
to the gas preparation reaction chamber which is
ing Iuel gas, maintaining the decomposing zone
suitably maintained at a temperature of about
at a higher temperature than the regeneration
800 to 1100° C. Additional fuel is supplied to the
gas preparation chamber and for this purpose
zone by combustion of said fuel gas with a part
solid liquid or gaseous fuels may be employed,
and hydrogen by the action of the oxidizing gas
or the oxygen disengaged from said carrier, said
temperature being above about 500*‘ F. and suin
cient to disengage oxygen from the said oxygen
carrier, said combustion taking place in contact
with said carrier, then returning the oxygen car
30 rier to the regeneration zone and cooling the
from the oxygen generator. Part of the hydrogen
serves to reduce the carbon dioxide to carbon
to condition it for absorbing oxygen from the air
such as coke, residual oils, fuel oils, natural gas,
etc. It is preferred to employ hydrocarbon gases,
particularly methane. In the preparation step,
the methane is converted to carbon monoxide
oxygen carrier in the regeneration zone sufficient
monoxide, an endothermic reaction absorbing
part of the heat generated by the action of the
charged thereto.
the reaction thermally. The temperature is con
trolled by regulating the proportion of methane
bustible carbonaceous gas therein in direct con
tact with said ?uidized oxygen carrier whereby
to oxygen employed in the gas preparation con
verter. Additional control may be obtained by
'carbon contained ‘in said combustible gas is con
2. The process of claim 1 wherein the said de
oxygen on the methane, thus serving to balance 35 composing zone is heated by introducing a com
verted to carbon dioxide, and separating the re
segregating a portion of the oxygen-CO2 product 40 sulting carbon dioxide from the oxygen produced
in said decomposing zone.
from the oxygen generator, extracting CO2 from
it, e. g. by solution in water under pressure or by
selective solvents such as triethanolamine, so
dium carbonate, etc., and then charging it to the
gas preparation reactor, preferably after reheat- -
ing in a suitable heat exchanger. superheated
steam may also be supplied to the gas preparation
reactor to assist in controlling the composition
of the products, particularly the ratio of hydrogen
3. The process of claim 1 wherein the fuel gas
introduced into said decomposing zone is hy
drogen, and steam formed by the combustion of
said hydrogen-is subsequently removed from the
disengaged oxygen by condensation.
4. The process of making oxygen from air
which comprises contacting with air in an ab
sorption zone at an elevated temperature a
to carbon monoxide produced. For some reactions 50 ?uidized solid oxygen absorbent material com
prised of a dissociable oxygen compound of a
it is desirable to make a synthesis gas having a
metal of variable state of oxidation, continuously
ratio of hydrogen to carbon monoxide of 2:1
transferring a- stream of absorbent material
whereas in other operations lower hydrogen ratios
charged with oxygen and substantially free of
are desirable, e. g. 1.5:1. A higher ratio of hy
drogen to carbon monoxide is usually desirable 65 nitrogen to an oxygen liberation zone main
where the gas is employed in the synthesis of
tained at an oxygen liberation temperature Sl1b—
methanol. Where the gas is desired for the
stantially higher than the temperature of said
methanol synthesis rather than hydrocarbon
absorption zone, injecting a disengaging fuel
synthesis as in the Fischer process, the gas prep
gas into said liberation zone in contact with said
aration converter may be operated under condi
absorbent material, thereby facilitating the lib
tions to allow carbon dioxide to remain ‘unre
eraton of oxygen by heating said absorbent ma
duced in the product gases and the carbon dioxide
terial above about 500° F. by the combustion of
can be converted to methanol in the methanol
said fuel gas in contact with said absorbent ma
synthesis step.
.
terial, withdrawing oxygen from said oxygen
Although I have described ‘the application of
liberation zone, continuously transferring ?uid
my invention to certain speci?c processes, it
ized absorbent material back to said absorption
should be understood that this is by way of illus
zone and cooling it by contact with air therein,
tration and is not a limitation of the scope, of
and eliminating from said absorption zone ni
the invention. In addition to the application of 70 trogen gas containing a lower concentration of
the invention to the process of oxygen recovery,
oxygen than that present in the air supplied
it may also beapplied to conversion of hydro
thereto.
carbon gases, cracking of hydrocarbon oils,
5. The process of claim 4 wherein heat for the
puri?cation of gases, for example desulfurization operation of said oxygen-liberation zone is ob
and decarbonation, and in general any process 75 tained by combustion of hydrogen with a portion
0,400,000
11
of the oxygen llberated therein in contact with
ma absorbent material 1n and liberation zone.
Number
945,048
FRED L. SYMONDB.
984,221 ,
REFERENCES mm
.
The following reterences are of record in the
?le of this patent:
Name
1,124,304
1,899,184
,
UNITED STATES PATENTS
Number
1,048,812
£173,825
Dnte
1. 2.304.128
12
Name
Date
Rldley ____________ _- Jan. 4, 1910
Hornboatel ....... __ Feb. 14, 1911
Doherty _________ -_ Dec. 31, 1912
Danckwardt ______ __ Jan. 12.1915
De Slmo __________ -_ Feb. 28, 1933
Odell _____________ -_ Dec. 18. 1934
Baives ___________ _.. Feb. 14, 1939
Curtis et a1 _______ __ Sept. 26. 1939
545,973
Purves ........ -;-- Sept. 10, was
“18.402
Thomas ___________ __ Dec. 8, 1942
Gorln _____________ _.. Apr. 1, 1947
588,617
874,598
Stuart ___________ __ Aug. 34, 1897
Janet ........... -- Dec. 94, 1907
3.435.754
Murphree et al____ .._ Aug. 19, 1947
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