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Патент USA US2404574

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Äwlîy 23, 1946.
„1_ A_‘s-` HAMMOND
Filed Nov. 30, ‘1945
Patented July 23,y v1946l
¿ UNITED , STATES vMT1-:1yr ori-'lcs-A
JohnA. S. Hammond, Glenbrook, Conn., assignor
to U. S. Industrial Chemicals, Inc., New York,
' N. Y., a corporation of Delaware
. ï Application November 3 o,
` 401mm.
1943, seriai No. 512,390>
(c1. ,z3-_288) ' "
operations particularly those in which a. gaseous
phase is passed through a shallow catalyst bed to
uniform on .both sides of and through the cata
lyst bed.
It is the object of the invention to provideA a
simple and effective apparatus which ensures uni
effect the desired reaction.
form flow of the gaseous phase to, through and
This invention relates to apparatus for Vcatalytic ’
In an application Ser. No. 509,124, ñled Novem
ber 5, 1943, Frederick R. Balcar has described a
from the catalyst bed and consequent improve
ment >in the efficiency of the reaction.
.method of producing acetaldehyde by
,Y Other objects and advantages of the invention
of ethyl alcohol in which a preheated. mixture of
will be apparent as it is better understood by ref
ethyl alcohol vapor and air is passed through a
erence to the following specification and accom
shallow catalyst bed consisting of `massive silver 10 panying drawing, in which
in the form of short rods having spacing means
Fig. 1 is a longitudinal section through an ap
integral therewith at a temperature of 30D-400° C.
paratus embodying the invention; and
The apparatus hereinafter described is particu
' Fig. 2 is a section on the line 2-2 of Fig. 1.
larly adapted to facilitate the operation of the
I have discovered that uniform ilow of a gas
Balear method. It is, however, equally appli
through a shallow catalyst bed can be established
cable and useful in other catalytic operations of
and maintained satisfactorily, in spite, of a rela
a similar nature in which the gaseous phase
tively low pressure drop, if the inlet and outlet
passes through a shallow catalyst bed.' Where
'connections to the catalyst bed are of conical
the catalyst bed is relatively shallow, that is of
shape having the proper dimensions.V To secure
the order of two inches in depth, the catalyst 20 the desired result, the length of the cone on each
offers relatively little resistance to the fiow of
side of the catalyst bed should be atleast five
gas, and there is therefore very little pressure
times'the diameter'of vthe catalyst bed. Thus,
drop across it. Thus,'in the operation described
for example, with a, bed 18 inches in diameter,
in the Balcar application, the difference in pres
the two cones on opposite sides thereof should
-sure between the upstream and downstream flows 25 be approximately 7 feet long, to secure the best
of gas is equivalent ‘to about 10 inches of water
results.v ' Obviously some, Variation from these di
or even less. Because of the low pressure drop,
mensions is possible, particularly if the full ad- inequalities of flow over portions of the bed may
vantages of the invention are not considered es- Y
be established with resulting detriment to the
sential. In general, the invention rests upon
efficiency of the operation.
y ..30 the fact that by employing a conical inlet and a
' If the rate of gas flow varies materially through
conical outlet of substantial length, the flow of
different portions of the catalyst bed, those por
gas to and from the catalyst bed and through
tions of the catalyst which are subjected to in
the bed is maintained at a substantially uniform
creased rates of flow may become inactive due to
rate, even though the pressure drop is relatively
the fact that the reaction zone has advanced so
slight. As a result, inequalities of flow through
close to the lower surface of the catalyst bed as
the catalyst bed are avoided and the efficiency
to be incapable of supporting further combustion.
of the operation is maintained. Measurements
The temperature of the remaining portions of the
with a Pitot tube have demonstrated the effec
bed will not be materially increased since the tem
tiveness of the apparatus in securing the desired
perature is limited by the composition of the inlet
uniformity of flow throughout the path of travel
gas. The conversion is very considerably lowered 40
of the gases.
and the yield may also‘be decreased. If the areas
Referring to the drawing,l5 indicates afcatalyst
of increased flow increase substantially in their
chamber which is preferably circular in cross
relation to the area of the entire catalyst bed,
section. It is provided with a grid 6 which sup
the reaction may cease entirely, due to the cool
ports a screen 'l carrying a shallow bed a of the
ing effect of the gases which do not react, since 45 catalyst, for example the silver rivets as described
the degree of preheat is generally considerably
by Balcar. Other catalysts may be employed to
below the temperature required to initiate and
facilitate various catalytic reactions in the gase
maintaining the reaction.
ous phase.
It isessential that the downstream as well as
`At the inlet end of the chamber 5, a cone 9 is
the upstream flow of gases be uniform. Any non 50 mounted. As indicated, the cone is of substan
uniformity of downstream flow will in turn> in
tial length compared` with the diameter of the
iiuence the pressure drop through the catalyst
catalyst chamber. It is connected to a pipe I0
bed and cause a non-uniform flow therethrough.
It is evident, therefore, that to maintain contin
uous and satisfactory operation, the flow must be
through which the gas preheated to the desired
temperature is introduced.
Ón the opposite side of the catalyst chamber
1. In an apparatus forrgaseous phase catalytic Y
operations, a catalytic zone of substantially uni
form cross-sectional area. and of relatively nar
similar cone I I is secured and connected to a pipe
I2 through'which the gaseous products are With
drawn. The chamber 5 and the cones 9 and II .
'row height arranged to receive a relatively shal
low catalyst bed, means to support said catalystV
bed in said zone, and conduits having portions
may be surrounded by- suitable insulating mate'
rial I3. In the apparatus as described, the enter-~
ing gasiÍlOWs,atgaxuniform rate ythrcluglrthe QQrle
ï9 and thecatalystiß. and thence through; thegcone
.substantially,î uniformly ?coniçal ,extending from
»the catalyst-zone on «,batìhfgsidesafthereof, the cone
' I I to the outlet pipe I2.
`shape'di'iortion's of said 'conduits being of sub-v
Theapparatus may be constructed of suitable 1_l0 `r,stantially the diameter of the ends of the catalytic
' material, depending upon the'particular reaction" ` ' v’zone at their bases and approximately five times 1
involved. It should, of -course',1be .ofvsuch material ‘ .« said diameter in length.
as not to affect the reactionlj‘çr thevproduction „
2. VIn an íapparatus for gaseous phase catalytic
of acetaldehyde from ethyl alcohol; the.. chamber
~ QperatíQllS,f-a catalytic zone of substantially uni
5 is preferably made of brass or stainlessvzv-Jste‘rel,'k
.fornncrpss'esectional area and of relatively nar
row -height arranged to Vreceive a relatively sha1
which should be coated withl silver inthe form
of a sheet or by electroplatingeor spraying'.
inlet cone 9; which isat relatively lovvftempera-V
Í ~ ‘illow:catalystbedkatsilver coated .grid and a screen
,tosupport said catalyst bed in said zone, and con
ture, may be made conveniently of Ycopper orÀ
brass. Thegoutlet cone I_I, being'at higher, tem
Y perature, is preferably -made ofv brass. Af‘17he_;gri_cl_ 6
sides/YL thereof,V «~ the ' cone’V shaped portions - off- said
is .also conveniently made of brass, Whichfshould
" be coated with silver. I p-refertomake theîscreen
"I ,ofg silver. "These detailsv concerningv materials
Aare lmerely by Way'oi'example in.` an apparatus
conduitsíbeifng -of substantiallyïgtheV Adiameter of
>the ends'of the-catalytic- zone at their basesand
approximately five timessaidídiameter in length.
'3.„Ifn an apparatusr` for gaseousphas'e catalytic
"operations, ar’silver lined catalytic zone of`sub
intended toV improve the. efficiency; of»- aparticular
~ operation. Any material may beiused Whichvrill
' st‘aifitialßly'- uniform cross-sectionalarea,"V and of
, relatiyelyfnarrow; height "arrangedto' receive a
vwithstand the temperatures'and_isjinnocuouswith
respect to. the >entering.gases vand theA products of
vthe reaction, or, in other Wordsgrlo .not` interfere
with the. intended reactiongwhich 'isfeiîected' by
‘the catalyst used.V
duits v.having portions substantially uniformly
Aconical extending from the catalyst zone on both
_ _ing y portionsl substantially uniformly -conical ex
tending .'.frQm fthe. Catalyst 20.11@ pon '.bO'bhÍsides
» ' The dimensions may varylwidiçly, :depending
thereefrtne ccneßhaped; pprtìons' of. .Said _conduits
upon the contemplated reaction. j;li‘or the purpose
of converting `iíthylyalcoh'ol toacetaldehyde; the
l,being {o'f substantially the diameter of the; ends
...of ,thecatalyticgzone atv then-¿bases andV approxi
mately; iiye‘Í times;I said diameter yinülength. Í?
` . _ catalyst "chan‘iber"v 5 ’;may_..haveï, aníinternalfdiam
eter of 18.r 'inchesand rmay' beapproxiznate’ly: 12
Vinches in length. ' .The twouconesf 9,Y and. I l ,`_ are
each approximately ."7jy feet ' in length, Ytapering
.4. VIn an, apparatus. for-.gaseçus .phase catalytic
’ ._operabíona aäçatalyticA zofne of .substantiallyguni
` l from .thecifameterv~ofihe.fcacncnr~chaniberac a 40
diameter .of .about ,.4 inches. . 'Such an ¿apparatus
isY highly efûcie'ntin .the catalyticconyersion of
ethyl alcohol. to4 acetaldehydfiand,h asindicated,
the. principles may, beE appliedto similar .catalytic
. operations.
Various chang"esamay'> be madeV in the détails vof
construction, the materials. usedand thediinen
. sions - Without Adeparting 5 from ._the îinventionàor
sacriñcing theadvantages thereof. ' Y
' relatively *shallow* catalystibed,> meansl to'ïsupport
vsaidcatalyst bed4 in- said zone, Yand conduits vhav
y _form„_cross-'sectiona1:areafand .0f relatively nar
row. .height arra?eedgto. receivèa relatively. sha1
' low catalystî bed, lrn'ean's'jcro'.s'ulvoport' said catalyst
bedÁn. said zone, `andronduits einen-ferrous
metal having portions, 51,110.5tantiallyA uniformly
Y , conical, extending fromthe, Cavrta'',Y onfborth
sides» thereof,v thefaco‘ne ßshaped portions ~:of said
.conduits _being ¿of substantially the A diameter . of
V„thegends‘pf ¿the catalytic. zone, at their, ' lsßsgand
Y. approximately llive, times .saidE diamêßen-ìn length.
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