US1043580A - Catalytic body. - Google Patents

Description

B. E. ELDRED.

GATALYTIG BODY.

APPLIOATION IILBD JAIL7, 190s. RENEWED MAY 9, 1912.

Patented Nov. 5, 1912.

6 & Inventor: 8

61,7 :1 ttys UNITED sTArEs PATENToEmoE. r

BYRON E. ELDRED, OF BRONXVILLE, NEW YORK, nssrciiion TO THE coMMEEoIAL- RESEARCH COMPANY, OF NEW YORK, N; Y. A CORPORATION or NEW YORK.

CATALYTIC BODY.

Specification of Letters Patent.

Application filed January 7, 1908, Serial No. 409,622. Renewed MayB, 1912. Serial No. 696,279.; I

skilled in the art to which it appertains to make and use the same.

This invention relates to catalytlc bodies and consists in catalytic bodies or devices comprising compound metal bodies having a core of one metal and an enveloping sheath of another and catalytically acting metal, such core and sheath being firmly and permanently welded or united together with a cohering union in such manner as to assure both mechanical strength to such union and good thermal conductivity between said joined metals; all more fully hereinafter set forth and as claimed.

Many metals possess what is called a catalytic power of ]')romoting reactions in mixtures of gases or liquids contacted with them, as in the action of platinum in bringing about limited or complete oxidation of mixtures of combustible gases or vapors with oxygen, the hydrogenating action of'nickel and cobalt in causing the union of hydrogen with various carbon compounds, etc. Since the amount of such catalytic action performed in a given time unit in a body of gas is strictly proportionate to the exposed surface of catalyzing metal, it-is customary to use such metals in finely divided form, sometimes as masses of powder and sometimes as powders adhering to and held by inert porous materials, such as asbestos, glass wool and the like. These expedients however while giving great surface to a given amount of metal, do not give a proportionately great exposure of such metal to the gases or vapors to be treated. It is substantially impossible to drive or distribute gases uniformly throughout a body of powder, and in passing gases over a body of such powder it is substantially only the top layers of the powder which display a maximum activity, underlying layers not functioning to any great extent. Use of-very thin layers of powder of course necessitates unduly extended shelf surfaoe. Incorporation of the finely divided metal in asbestosor glasswool works better, but since such'powders do not as a rule adhere well to the carrier it is nece essary to employ such carrier rather. closely packed or in a form which renders difiicult the circulation of gases therethrough. Impregnation of the carrier with the metal and formation ofthe carrier into balls or pellets is therefore resorted to, but in this manner of operation the metal in the i'nteridi' ofa ball or pellet is of relatively little use. An other and more serious difiiculty with the described ways of using catalytic metals consists 1n the difliculty oftemper'ature reg ulation. Nearly all catalyses are exothermic reactions, heat being developed by the' ac-- tion, and frequently the amount of heat is rather large, And as it is usually desirable to work within comparatively narrow temperature limits, keeping and maintaining the catalytic metal within a few degrees of some definite temperature, this evolution of heat is a serious matter. Nearly all the catalytically acting metals are relatively poor conductors of heat, even in the reguline form, and in the form of powders they are worse. It-is difficult to keep a body of platinum powder at any definite temperature,

Patented Nov. 5,1912.

and when the platinum is distributed through a mass of such a heat-insulator as asbestos, it is very hard to prevent the accumulation of reaction heat in the metal.

It is the purpose of the present invention to obviate the described difiiculties by the provision of catalytic bodies comprising the catalytic metal in the form of very thin continuous layers or filmsv carried by bodies of better heat-conducting metals weld-united to such layers or films and therefore in absolute metallic union therewith whereby by controlling the temperature of the carrying metal the temperature of the film or layer can also be controlled. Being so thin, the heat conducting qualities of the film metal are more or less immaterial. It is obvious that with such very thin films, a given weight of the catalytic metal can be given an enormous surface while by carrying the film'on a substantial body of the core metal the compound catalyst can be given shapes or forms suited to induce thorough contact with a current of gas or vapor, as in using produced by the method described by the use of shaped gauze or leaf-metal wings or vanes 1n such conduits 1n forms adapted to produce vortices in passmg gases,

or by. the use of staggered sheet metal partitions in such conduits. In whatever form the compound metal catalyst be employed, it is desirable that it be in thermal contact with heat-interchanging elements in or on the vessel carrying or containing thegases or vapors to be catalyzed so that definite temperatures may be maintained in such catalyst. If the catalyst be in the form of wires, for instance, such wires may be threaded at their base into a larger body of metal or they may be butt-welded to copper and similar wires or rods extending into another chamber carrying a heating or cooling fluid.

Suitable catalysts under the present invention may be madeby welding a sheath or coating of platinum on a billet of copperor steel or soft iron,-and coextending the joined nretals to form wire or-sheet metal. If 3 to per cent. of platinum be placed on the original billet and coextension be performed with care, the wire, sheet or leaf metal formed will also have 3 to 10 per cent. of platinum but this thickness-in such coextended ware will correspond to an extremely tenuous layer. Steel and platinum do not readily unite directly, but as I have discovered, their union'can be produced by contacting clean platinum with clean molten steel; one/method of doing this being set forth in my companion application Ser. No. 409,617, filed Jan. 7, 1908. Unions produced in this manner are, or are equivalent to, weld unions and .the joined metalsf-canbe coextended in'the samemanner assteel alone. By using a soft steel or pure iron, such as, for instance, that produced in the Tropenas process, very good thermal conductivity can.

be obtained in the core metal. A pure iron core'being shielded by the platinum sheath,

the joined metals can be worked together without contamination of such iron; a matter which is, with naked pure iron, rather difiicult. Copper cored platinum can be produced. by contacting hot clean copper, either molten or nearthe melting 'point, with clean platinum. as disclosed in my copending applications Ser. No. 409,618 and Ser. No. 409,620, both filed Jan. 7, 1908. Gold and silver cored platinum may be produced in similar manner. As copper, gold and silver unite with platinum with less difliculty than does steel, the steel may be preliminarily filmed or coated with one of these metals prior to applying the platinum. Steel permanently, firmly and autogenously united to coatings of copper, silver or gol' may be .J. F. Monnot in his Patent No. 853,716, aii d such coated steel may be employed in producing platinum coated billets which may then be drawn, rolled or otherwise extended to form the platinum filmed catalysts of the present invention.

In use, the catalytic metals are apt to becou'e more or less'porous or fissured, and, with the film coatings of the present invention, avenues may be opened whereby corrosive gases or liquids may gain access to the underlying core metal. In some catalyses where corrosive bodies are produced, as in the union of sulfur dioxid with oxygen to produce sulfur trioxid, if the core metal be readily corrodible, as is the case with steel, this phenomenon may be disadvantageous. Gold and silver not being catalytic metals to any extent are not subject to 'this fissuring or porosity, and by using either as a linking layer, the core metal may be kept hermetically sealed. The same is true of copper, though to a rather less extent. It is however very well adapted for cases where the corrosive body produced is, as in the case of oxidizing alcohol to acetic acid, only feebly corrosive.

The core metal may be, and very advantageously, either gold or silver. Both are highly conductive for heat. Using either metal as a linkinglayer between platinum and iron, they serve to convey and equalize the heat in the core. The same is true of copper as a linking layer.

The porosity of the catalytic film may be purposely produced, and particularly where a linking layer is employed with a ferrous metal core, or where a copper, gold or silver core is em loyed. In the case of platinum, this may 'e done by treating the platinum-filmed catalysts .with corroding agents, either liquid or gaseous, such as aqua regia or bromin water or chlorin gas, and subsequently heating. The attack of these reagents upon the film should of course not be prolonged. In the case of catalysts carrying fihned cobalt or nickel, the catalysts may be slightly oxidized by heatin in air and then reduced in a current of ydrogen or other combustible gas.

Catalysts according to the present invention may be employed in a wide variety of. catalytic reactions, such as the production of aldehydes and acids by limited oxidation of alcohols in the presence of air, as in the formation of acetaldehyde or acetic acid from ethyl alcohol or formaldehyde from methyl alcohol, the production of sulfur trioxid by the oxidation of sulfur dioxid, ignition of combustible gases, as in self-lighting gas burners, the hydrogenati m of carbon compounds by cobalt and nickel, as inreducing carbon monoxid or dioxid to methane in the presence of hydrogen, the formation of isopropy alcohol by catalyzing a mixture of hydrogen and acetone, the formation of hexhydrolmizol :t'rom benzol and hydrogen, etc. In these reactions, as stated, heat :is generally produced while it is desirable that the iatalyst be maintained at a t-olerably.uniform temperature. It is for this reason that the catalyst should generally be maintained in thermal contact with a mass of metal provided with heating or cooling means.

In the accompanying more or less dia gramn'iatic illustrations.I show sundry embodiments of the described invention.

In this showing, Figure 1". illustrates a cross-section (dimensions being exaggerated) of a wire composed of a core 1 of iron, copper, gold. silver. etc having united thereto a tilm fi'of a catalytic metal such as platinum,. palladium. nickel, cobalt, etc. Fig. illustrates a similar view ,of a wire having core and catalytic film sheath linked by an' intermediate layer, 2, of a conductive, non-catalyzing metal such as gold, silver or copper,, weld-united on either side to core and sheath. Fig. 3 is a similar. view of a sheet or leaf of compound metal composed of core land sheath 3. Fig. 4 is a crosssection of an apparatus. utilizing the cataiysts of the present. invention, it being a-con: duit for carrying gases or yapors to be. catalyzed. '5 compound metal wires spanning the.

same. (i a" body of metal to'which they are muted and 7 a heat-mterchangmg picket;

'Fig. 5 is a similar view in which the-heat conduit 6 and soldered or otherwise secured to its walls. Fig. 8 isa view in vertical cross-section and partial elevation of a complcte apparatus employing thedescribed catalyzers. a liquid vessel 10, provided with valvedliquid inlet 11 and valved gas inlet 12, communicating with a catalyzing conduit having catalytic gauze septa spanning it and in thermal relationship to a heat-interchanging jacket. is a pipe 13, passing through a condenser -ja.cket 14 into a seal-pot 15 from which uncon densed gases maybe withdrawn by fan Beyond the catalyzing conduit 16. Fig. 9 is a'detail view showing an advantageous method of constructing the gas conduit, such conduit being formed of two half-tubes, 17 and 18, each carrying catalyzing wires and each provided with a thermal jacket.

, In the use of the structure of Fig. 8, the liquid in 10 may be methyl alcohol and a regulatt-a'l amount of air sucked in tln'ough the gas inlet. by the fan shown. This air coming into contact: with the alcohol evaporates part of it and the mixture of air and vapor passes into intimate contact with the filmed catalyst on the wire-gauze septa shown, producing methyl aldehyde. Circulation of a suitable thermal fluid in the jacket: serves to control the temperature of the filmed catalytic metalby thermal conduction through the core metal. For producing formaldehyde in this manner, the catalytic metal is preferably platinum and the core metal copper or steel. The formaldehyde passes through the condenser and accumulates in the body of liquid in the seal pot. For making isopropyl alcohol. the liquid may be acetone and the gas introduced hydrogen, while the catalytic metal is preterably nickelor cobalt. The thermal jacket should be used in this case to maintain a temperature quite a little above the boiling" point of water With a nickel catalyst, the liquid maybe benzol (CJL) and the gas hydrogen. hexahydrobenzol being' produced.

In producing sulfur trioxid, the catalytic body maybe very advantageously filmed platinum carried by a copper core with a linking layer of gold or silver between, rapid exchange of heat being Very necessary in this instance. In forming methane from water gas, etc., the catalyst is advantageously nickel filmed 011 steel or soft iron.

In producing the catalytic bodies, it is inadvisable to unite the'coating of catalytic body to the original billet by any form of solder, solder not standing the great extension necessary to produce the desired filmiform catalytic metal. when the metals/are actually welded to- :gether the coating catalyst may be extended to atenuity at which it would beutterly unable to exist alone, as it can rely on the welded core for support. With a weldunion, thern'ia'l conduction is perfect.

Where, as frequently happens in catalyses,

the amount of heat developed in the. reaction is insuflicient to maintain the apparatus at the desired temperature, heat may of course be supplied totbe catalyst through the intcrmediancy of the heat interchanger.

What I claim is,:- 1. In a catalyzing apparatus, the combination of a catalytic body comprising acore of relatively heat-conductive metal provided with a filmiform continuous coating layer of a relatively less heat-conductive catalytic On the other hand,

2. In a catalyzing apparatus, the combination of a catalytic body comprising a core of a relatively heat-conductive metal provided with a filmiform. continuous co ning layer of a relatively less heat-conductive catalytic metal in heat-conducting relationship. thereto, said coating layer and'said core metal being metallically united to an intermediate linking layer of another metal,-

and heat-controlling means in thermal relationship to said catalytic body.

3. A catalytic apparatus provided with an element comprising a coreof heat 'conductive metal carrying a continuous-'filmifomn layer of platinum in heat conducting relationship thereto.

4:. A catalytic body comprising a core of heat conductive metal carrying a continuous filmiform layer of platinum in heat-conducting relationship thereto, both said metals belng weld-united to an intermediate linking layer of another metal.

5. In a catalyzing apparatus, the combination of a catalytic body comprising a core of a relatively heat-conductive metal provided with a continuous filmifoi'm coating layer of a relatively less heat-conductive catalytic-metal in heat-conducting relationship thereto, the surface of said catalytic metal being porous, and heat-controlling means in thermal relationship to said catalytic body.

.6. A catalytic body comprising a core of heat conductive metal carrying a continuous filmiform layer of catalytic metal in heat conducting relationship thereto, both said metals being weld-united to an intermediate impervious linking layer of another metal and the surface-of the catalytic metal being porous.

7f, Ina catalyzer, the combination of a catalytic body comprising a core of heat conductive metal carrying a filmiform layer of a relatively less conductive catalytic metal;

in heat conducting relationship thereto with a heat interchan er in heat-conducting rela-' tionship with said catalytic body.

8. In a catalyzer, the combination of a catalytic body comprising a core of heat 1' conductive metal carrying a filmiformlayer of a relatively less conductive catalytic metal in heat conducting relationship thereto and having an iutermediatelinking layer of another metal weld-united to both such metals, with a heat interchanger in heat conducting relationship to said catalytic body.

9. In a catalyzer, the combination of a catalytic body comprising a core of heat conducting metal carrying a filmiform layer of platinum in heat conducting relationship thereto, with' a heat interchanger in heat conducting relationship to said catalytic body.

10. In a catalyzer, "the combination of 'av BYRON E. ELDRED.

Witnesses:

K. P. MCELROY, H. M. MARBLE.

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