US2248994A - Combustion of carbon monoxide - Google Patents

Description

E. J. HOUDRY COMBUSTION OF CARBON MONOXIDE July 15, 1941.-

2 Sheets-Sheet 2 Filed April 4, 1939 Air, Afomized. wafer, or us] INVENTOR guczmz dHou DRY ATTORNEY V tailed description which must be exercised to supply Patented July 15, 1941 Eugene J. Houdry, 'Ardmore, Pa., Houdry Process Corporation, W a .corporation of Delaware assignor to ilmington, Del.,

Application April 4, 1939, Serial No. 266,010

11 Claims.

This is a substitute for and continuation-inpart of my copending application Serial No. 78,542 filed May a, 1936.

The invention relates to chemical reactions and more particularly to the oxidation or combustion of carbon monoxide and other burnable material in a gaseous stream. H

One object of the invention is to add energy to a gaseous stream. Another object is to raise the temperature of a gaseous stream. Another object is to eliminate toxic, explosive, and in: completely oxidized components of a gaseous stream. Still another object is to devise suitable apparatus for carry g out the above objects. Still other objects will be apparent from the defollows.

The invention involves the addition of heat to a gaseous stream, such as gaseous mixtures ineluding fumes or waste gases from a combustion, catalystregeneration, or other zone, by efiecting oxidation or .CO and other burnable material. If the gases are at a suitable high temperature, as above 1000 F. and oxygen is present, the combustion may be efi'ected in the presence of mere spreading material. If it is desirable to operate at a temperature somewhat below 1000 F., a catalytic agent which will supply oxygen may be utilized. If an oxidizing medium such as air is added to the waste gases, the reaction can be carried on at a still lower temperature. The gaseous stream, when below reaction temperature, is preferably brought thereto by passing it in heat exchange relation with the contact mass or catalytic agent. It air or other oxidizing medium is added to the gaseous stream, care it in amounts below the requirement for an ermlosive mixture. when the gaseous stream contains hydrocarbon vapors and their elimination is portant, a highly porous contact mass should e utilized which will withstand the operating temperature and-winch will retain the vapors by absorption and/or adsorption until burning is efi'ected through the action otthe oxidizing agent.

While the invention iscapabl'e of rather general-application, it is of special. importance in connection with the treatment of regeneration fumes from catalytic converters and such a use is indicated in the copending applicationof myself and R. S.'Vose, 'Se *ial No. 58,858, filed January 13, 1936 which issued August 1, 1939 as U. S. Patent 2,167,655,.

In order to illustrate the invention, concrete embodiments of apparatus, capable of practising it, are disclosed in the accompanying drawings,

in which:

Fig. 1 is a vertical sectional view through a small unit, the section being made substantially "on the line i-I of Fig. 2;

Fig. 2 is a transverse sectional view substantially on the line 2-2 of Fig.1;

Fig. 3 is a fragmentary or leit half section of Fig. 1, showing a modification; and

M, defined by a tubular member 5 having screw-- threaded connection with-a lower header 6 and welded to an upper header member I. An outlet'pipe 8 leads from the upper end of the reaction chamber for the discharge of the neutral heated fumes which are conducted away to suitable apparatus diagrammatically indicated at 9 for utilization of kinetic or heat energy in the gaseous stream.

' The gaseous material to be treated may enter I the lower end of the reaction zone by an inlet pipe [0 extending through header 6. To insure the stream entering the zone at the proper temperature and also to give a measure of control of the reaction through removal of at least a portion of the heat of reaction, the stream, prior to its admission to pipe I0, is brought into extended heat exchange with the reaction zone, but such heat exchange is confined, primarily, to radiation. By preference, the gaseous stream picks up heatfprogressively as it is*caused to traverse the length or depth of the reaction zone. In Figs. 1, 2 and 3, the heat exchange is eiiected upon the exterior of the reaction zone. As indicated, feed conduit II is formed in a coil Ila.

which encircles the reaction zonethroughout its length from outlet end 8 to inlet end Ill. The

turns of coil Ila may be maintained in definite spacial relation to tubular wall 5 of the reactionzone by suitable members such as rods or posts,

i2 (Figs. 1 and 2) which may be inserted through holes or bores 12a. in upper header I, while the opposite ends are received in sockets I211 in lower header 6. A wire, cotterpin, or other member is inserted through the rods as at I26 to" retain them in place. To controlthe quantity-of heat absorbed by the feed per unitof length of the reaction chamber, and to provide for expansion of the stream, coils Ila may be increased in size Fig. 4 is a vertical, sectional. view with certain parts shown in elevation of a difierent and larger 2 as they approach inlet it, this increase being effected in-stages by the use of sections of pipe of increased diameter, or gradually and progressively as indicatedin Fig. 1. The lower end of coil li is joinedto inlet conduit' ill by a suitable connection 13. To prevent loss of heat from the unit, an outer casing 14, which is preferably in sections to allow for the pipe connections II and l3,-is secured to upper and lower headers I and 6 in anyjguitable manner, as by seating the lower end in an annular recess 6a in lower header 6, while the upper end is attached or clamped to header 1 as by a split ring IS. A layer 'oi'heat fluid through the mass, such conduits extending through partition 24 to communicate with manifolding chamber 26. The entire casing is lagged with heat insulating material as indicated at 29, and, in addition, the inner walls of inlet manifolding chamber 25 are lined with a layer 25a of heat insulating material. Y

In the apparatus units illustrated in the drawings, it is apparent that the gases to beoxidized are passed through the conduits in radiant heat exchange with the walls which definathe reaction 1 chamber and which enclose the catalytic 'or other insulating material it may be applied-to the entire exterior of the unit.

Progressive pickup of heat by radiation may, be effected between the feed and the reaction zone in other ways. If it is not desired to incontact mass, and that provision .is made to increase the temperature of -the reactants ,by increased surface areas, by baflies, or by other means so as .to remove substantially equal amounts of heat from all-parts of the reaction zone. -When very large quantities of heat are crease the size or diameter of the conduit making up coil Ila, a conduit of uniform diameter may be utilized, but the pitch of the coil may be decreased as lower header 6 is approached by making the coils closer together, thereby increasing the'radiating surface. If uneven spacing of the coils is objectionable, the same effect of progressive heat exchange-may be secured by attaching plates of, different sizes indicated at I! (Fig.3) to the conduit coils I lb,'as by welding.

If such a large. volume of gas must be treated that the type of unit shown in Figs. 1 to 3 is unsuitable, a different unit, such as shown in Fig. 4, may be utilized. This unitcomprises a central cylindrical member 20 having end closures 2| and 22 and upper and lower partitions or flue sheets.

23 and 24 dividing the interior of the case into a large central reaction chamber to contain the contact mass or catalyst M and end manifolding chambers 25 and 26. Assuming that the gaseous stream enters the manifolding chamber 25, it is brought into heat exchange with mass M through suitable perforated heat exchange and distributing members 21 embedded in the mass. They may be supported by upper partition 23 and extend substantially through the reaction chamber.

' One of these members (the central one) is shown in section and comprises an inner conduit 27a which communicates through partition 2; withmanif olding chamber 25 on the one hand and discharges the gas at the very bottom of the outer conduit 21b which is spaced from and encloses the inner conduit. Outer'conduit 21b has perforations throughout its length for discharging the gaseous material at reaction temperature dicombustion chamber.

rectly into contact mass M. To insure a. substantially even pickup of heat by the gaseous stream from the contact mass as it'passes through inner conduit 21a, suitable heat baflling means, suchas baflle members 210 and 21d of different length are provided. Instead of sheet metal baffles, such as indicated, heat insulating material may be utilized as a substitute for or in combination with such baffles. as indicated, ,for example. in-

U. S. PatentNo. 1,987,636, issued January 15, 1935 to T. B. Prickett and myself, and in U. '5. Patent Nd. 1,987,933 issued January 15, 1935 to J. W. Harrison. The gases, after being distributed uniformly at substantially even temperature all through mass M, maypass therefrom through suitable perforations in partition 24 into outlet manifolding chamber 26, or may be withdrawn uniformly from all parts of the mass by perforated conduits such as 28 embedded in the contact mass in symmetrical arrangement and in paral? lelism withjthe distributing and heat exchange liberated within the converter the cooling effect of the entering reactants may be supplemented by extraneous heat exchange fluid which may optionally be mixed with the entering reactants or sent through the reaction zone in suitable conduits as indicated for example in the aforesaid Harrison Patent No. 1,987,933 or.in Patent No. 2,078,947 issued May 4, 1937 to-myself. and R. C. Lassiat.

One reaction to which the process is particularly adapted is in the combustion of carbon monoxide and/or oil vapors which may be present in regenerating fumes issuing from a catalytic converter "for the purpose of increasing the energy content of the fumes, which may be thereafter recovered either as kinetic "energy or as heat energy or both, as indicated, for example in the aforesaid copending application of myself and R. S. Vose. The combustion is best effected when a contact mass is employed. The massmay vary in characte depending upon the temperature at which the gaseous stream enters the When it enters at high temperatures, as of, the order of 1000 F. or more,- and containing suilicient oxygen, the contact 'mass may be mere inert spreading material, .but preferably of a highly porous naturefi'so as to retain oil vapors and the like until combustion. is efiected, such as pumice, kaolin, firebrick, and other blends ofv silica and alumina. This material is preferably in the form of lumps, fragments, or molded pieces.

When the gaseous stream enters the combustion zone at a temperature below 1000 F., as of the order of 900 F., the contact mass may comprise or contain catalytic material, such, for example, as metallic oxide's andcompounds, including those of copper, iron, cobalt, 'nickel "and lead. The metals may be utilized directly, as in the form of shavings or turnings. or the metal or metallic compound may be in finely divided form on or incorporated in suitable supports such as inert or active blends of silica and alumina of natural or artificial origin, preferably in the form .of lumps,. fragments, or molded pieces. If' the operation isto be effected with members 27 to effect a parallel flow of the gaseous initial temperatures much below 900 F as :of the order of 700--'F., it is sometimes desirable to add air or other oxidizing medium to the fumes. This medium should be added in amounts below that which will give an-explosive mixture with the carbon monoxide'and other burnable material which may be present in the gaseous stream. For fumes from the regeneration of catalytic material in a converter utilized for the conversion or treat;

ment ofhydrocarbons, up to about 6% of air is suitable. This may be added-before the stream' th fumes may enter t is brought intoheat exchange with the reaction zone, as, for example, by branched pipe 30 (Figs.

1 and 4). Other fluids, such as non-explosive fuel c extraneous cooling fluid such as atomized water, inert gas, etc. may be'added at this point to control the entering and exit temperature of the gaseous stream. A more preferable point of admission of air is just before the gaseous stream enters the reaction zone, as by branched pipe 3| (Fig. 1). However, the oxidizing medium can be admitted at either point in Figs. 1 and 2,

power, the maximum operating temperature of the fumes is of the order I 950 F. In that case. reaction chamber at about 750 F. under pressure and the rate of heat removal from the chamber regulated to provide a temperature rise of the fumes of about 200 F. For heat recovery purposes, higher temperatures in the fumes could be utilized, as up to 1200 F., but such high temperatures would require the use of-alloy or other special steels in the combustion iinit to stand such tempera tures.

The rate of feed of the gaseous stream and of any other cooling fluid to the combustion zone is adjusted to attain a wall temperature such that no part of the contact mass is cooled below predetermined and preferably substantially constant operating or oxidizing temperature. Hence rates of feedwill vary with diiferent ratios of heat exchange surfaces to volume of catalyst.

with decreased concentrations of burnable material. Rates up to 60:1 (sixty volumes of charge to one volume of contact mass) per minute have been used. A good rate for a gaseousstream supplied at 520 F. and containing about 2% CO by volume and .2% hydrocarbons by weight is about 13:1 in a reaction chamber having a contact mass volume to heat-exchange-surface area of about 1:16, the 'mass comprising hydrosilicate of alumina with copper oxide content of about 15% by weight. The operation gives a final or outlet temperature of about 920 F.,-thus providing in-' crease in temperature of the gaseous stream of about 400 F.

Theoretically, to oxidize 1 pound of oil or other similar burnable material; 3% pounds of oxygen. are required which can be provided by 14 pounds of copper as copper oxide (CuO) based on complete reduction of Cut) to Cu; and to oxidize 100 cubic feet of CO there-is required 4.25 pounds of oxygen which can be supplied by 17 pounds of copper. When oxygen is present or is added to the stream, smaller quantities of catalyst. or oxidation promoter may be used. In practice, it is advisable to supply a large excess of oxidation promoter, as five to ten times the theoretical amounts, to insure a suflicient amount'of active material, thus providing for (a) variations in the composition of the gaseous stream, (b) channelling of the mass, progressive poisoning by formation of sulphates, and (d) incomplete reduction of the oxide to metal. Relative amounts of the listed metals other than copper may be utilizedysome regard being given to their atomic weights and to themolecular weights of their oxides.

The maximum. amount of oxidation promoter which can be used in a given volume of space is dependent upon the rate 30 in the contact mass.

be removed by suitable heat exchange surfaces. Hence, when the contact mass is a poor conductor of heat, such as -a silica-alumina blend, it has been found .desirable-toincorporate therein only a restricted amount of the promoter, as

not more than by weight of the mass, by reason of the sharp rise-in temperature which occurs when the promoteris reoxidized.

The combustion reaction .is effected equally y 10. well under pressure or without pressure. When kinetic energy is recovered,- the addition of atomized water, cool gas, and the like under pressure at branch 30 in advance of the heat exchange zone is of importance not only as-a means of I 15 temperature control of the reaction zone, but alsoas a means of increasing the recoverableenergy of the gaseous 'stream. In most instances, the gaseous stream which is fed to the combustion zone will contain sulphur compounds of 20 some kind, such as H28, S02, S03, etc., which are removed from the gaseous stream in combining with the promoter to form sulphates, thereby producing a gradual poisoning of the catalyst while the latter purifies the =,gaseous stream of its corrosive or sulphurous constituents.

Hence regeneration will be required from time to time at more or less infrequent intervals de-. pending uponthe composition of the gaseous stream and upon the quantity of metallic oxide duction, and hydrogen, or a hydrogen carrier such as refinery gas, may be utilized.

Of the metallic oxides mentioned above, copper oxide was found to give the best result and to promote oxidation for the longest period. It is There is also a tendency to increase feed rates the only one which acts when no oxygen is present in the gaseous stream, but this oxide must be at relatively high temperature, good results being obtained for example at about 900 F. When 40 used in suitable amount, copper oxide is capable of supplying oxygen for combustion for the burning of oil vapors and carbon monoxide when there is little or no oxygen present in the gaseous stream, as, for example, during the early stages of regeneration of catalytic material. The copper.

catalyst easily regains its oxygen, and is reconverted to copper oxide, asduring the latter stages of a regenerating period, when substantial amounts of oxygen are unused during the regeneration and are accordingly present in the gaseous stream. When small amounts of air are admitted to the gaseous stream, as up to '6%, the copper catalyst functions efliciently at temperatures of about 700 F. All C0 and other bumable material is consumed, and the resulting fumes are inert and hence capable 'of utilization where material of this characteris needed. One use is as a purging agent for catalytic masses, as, for example, when other purging agents, such as steam, are not available or cannot be used. It can also be used as vaporizing or other process fluid, and for repressuring of converters after vacuum purging operations.

Apparatus aspects of the invention are claimed in my copending divisional application Serial .No. 255,459, filed February 9, 1939.

I claim as my invention? 1. The process of producing a stream of sub-'- stantially inert fluid of controlled recoverable 'energy content comprising ,the steps of passing at which heat can pended unburned organic material, regulating Regeneration is by rethe temperature of the o of the stream of burned gases issuing therefrom burnable deposits in contact masses of.

out the same, maintaining said 'termined combustion promoter and and from the reaction zone at predetermined and substantially constant level 700 to 1200 F., and effecting such regulation at least in part by absorbing excess heat of combu'stion in a stream of extraneous cooling 'fluid passed in indirect heat exchange relationwith the-combustion zone. i

2. In the treatment of regeneration fumes containing burnable components including. carbon monoxide and resulting from removal of burnable deposits from contact masses, the" process of passinga stream of such fumes through a combustion zone containing a combustion promoter maintained under combustion conditions to convert such burnable components into inert fluid within the range ofa combustion with the aid of jazaaeee A fluid in heatjexchangerelation with said reaction zone before admittihg them to said mass.

6, The process of treating regeneration fumes containing burnable components and resulting from removal by combustion of burnable deposit from contact masses contaminated-by the same comprising the steps of subjecting a continuous stream of said fumes while still hot to controlled a contact mass contaihifig a combustion promoter to convert said burnable components into inert fluid and to produce a stream of process fluid of regulated energy content, admitting said fumes at substantially uniform temperature to a multiplicity of points and to increase the available energy content of said fumes, and maintaining gases issuing from said zone at predetermined and substantially constant temperature below 12GO F. by transferring heat ofcombustion from said zone to said fumes before entry of said fumes to said combustion zone.

3. In the production from'combustiongases containing burnable components including car-.

the stream of inert bon monoxide and resulting from combustion of an inert process fluid of controlled energy content valuable for supplying industrial energy, the process of subjecting a stream of said gases to promoted burning ina combustion zoneto convert said burnable components into inert fluid, absorbing excess heat of reaction from said combustion zone at regulated rate by an extraneous heat exchange fluid to limit to a maximum ,of 400 perature increase of said gases in traversing said zone and to maintain predetermined and substantially constant temperature below"1200 F. in the stream of inert process fluid resulting from the combustion and issuing from said zone.

4. In the treatment of regeneration fumes containing burnable components and formedby burning combustible deposits 'from contact F. the temeffecting. at least a portion within and throughout said mass, simultaneously passing anextranens cooling fluid in heat exchange relation with said mass to remove excess heat of reaction therefrom and to maintain substantially uniform temperature within and throughout the same, and regulating absorption of reaction heat from said mass to provide predetermined and substantially constant temperature below 1200 F. in the burned fumes issuing from said mass. I

'l.- The,process of preparing for industrial use regeneration fumes containing burnable components including carbon monoxide issuing from acatalytic converter comprising the steps of send,- ing astream of suchfumes at temperature in excess of 500 F. into'a reactionzone containing .a contact mass capable of promoting combustion of said bumable componentsregulating reaction conditions through zone to a maximum of 400 delivery-of burned fumes-from the zone at substantially constant'temperature below 1200 F., of said heat absorption by passing the unburned fumes in indirect heat exchange relation with said mass, and maintaining substantially uniform temperature in said mass by progressively increasing radiant heat to promoted combustion with the aid of a' contact mass containing a metal or metal oxide combustion promoter to convert saidburnable components into ine t fluid, -maintaining the stream of burned fumesissuing from said mass at substantially constant temperature not in excess of 950'F., and regulating the temperature of said burned fumes by absorbing excess heat of combustion in an extraneous cooling fluid passed in direct heat exchange relation with said mass.

.5. In producing valuable process fluid from combustion gasescontaining burnable components' including carbon monoxide, the process of sending a stream of such gases under combustion conditions into and through a reaction zone containing a contact mass capable of promoting combustion of said burnable components, admitting a stream of said gases at substantially uniform temperature to said mass -at a multiplicity of points distributed within and throughmass at substantially constant temperature below l200 F; so that the stream of burned inertfumes issuing therefrom are at substa tially constant, p'redeindustrially practical temperature, and effecting such temperature ,controlby passing said gases diluted. with an extraneous cooling tion promoting mass exchange between the-zone and said unburned fumes, and, by admitting the heated fumes at.

substantially ,uniform temperature to the mass at a multiplicity of points distributed within and throughout the same.

8. In the.treatment of fumes made during regeneration by burning from contact masses carbonaceous deposit formed when the mass assists organic reactions, said fumes containing CO, hydrocarbons and quantities of oxygen varying from insufficient to excess, .the process comprising passing a stream of said fumes under combustion conditions through a single combusmade up of' a minor quantity of copper oxide in finely divided form distributed on aporousinert support which holds and retains unburned material suspended in said fumes, and. maintaining said mass at substan-- tially constant temperature within the range of 700 to 1200 F. by simultaneously passing said fumes and an extraneous'heat exchange fluid in heat exchange relation therewith, whereby a stream' of inert gases substantially free of burnable components suitable for industrial use issues from said mass at substantially constant and predetermined temperature, said mass supplying oxygen to the combustion reactions zduring periods of oxygen deficiency in the fumes and regaining a supply of oxygen for this purpose during later periods when the regenlerationfumes contain excess unused oxygen.

9. The process of prRiucing inert'gas of conabsorption of combustion; heat therefrom to limit temperature increase of the fumes during their passage through said F. and to provide and resulting from a period of regeneration-by burning of carbonaceous deposit from-a contact mass wherein said fumes are deficient in oiwgen early in' the regeneration period and later contain excess unused oxygen, comprising the steps of continuously passing a stream of said fumes throughva combustion promoting mass made upof copper oxide in finely divided form distributed on a porous support which holds and retains unburned material suspended in said fumes, and maintaining said mass at substantially constant trolled heat content from fumes containing C0. hydrocarbons and varying quantities of oxygen controlled amount of an extraneous cooling fluid generation fumes contain excess unused oxygen.

11. The process of producing inert gas of controlled heat content from combustion fumes contemperature not over 1000 F. by passing said fumes in heat exchange relation with said mass while simultaneously utilizing a stream of extraneous cooling fluid to assist the fumes in removing excess heat of reaction from the mass,

wherebythe stream of inert gases continuouslyissues from the mass at predetermined, substantially constant temperature and said copper oxide supplies oxygen to the combustion reactions early in the regeneration period and later in that period regains a supply of oxygen.

10. In the treatment of fumes made during regeneration by burning from contact masses carbonaceous deposit formed when the mass as-, sists organic reactions and containing CO, hydrocarbons and quantities of oxygen varying from excess to deficiency, he process comprising passing a stream of said fumes under combustion conditions through a single combustion promoting mass made up of about by weight of copper oxide in finely divided form distributed on' a porous support of a blend of silica and alumina, maintaining said mass at substantially taining CO, hydrocarbons and amounts of oxygen varying from excess to deficiency and resulting from a period of regeneration by burning of sulphur bearing carbonaceous deposit from a contact mass comprising the steps of passing a stream of the regeneration fumes at temperature in excess of 500 F. and under combustion conditions through a contact mass made up of an active metal oxide combustion promoter and desulphurizing agent distributed in finely di- .vided form on a porous siliceous support, regulating the temperature of said mass by simultaneously passing said fumes and an extraneous heat exchange fiuid in indirect heat exchange relation therewith to maintain the same at substantially constant temperature below 1200 F. and to limit temperature increase of the fumes during their conversion into inert gaseous form to a maximum of 400 F., and periodically passing reducing fluid through said mass to reduce to oxide form metallic sulphate formed in the mass constant temperature in the range of 700 to 1200 F. by passing said fumes diluted with a as a result of sulphur removal under combustion conditions.

EUGENE J. HOUDRY.

\ v CEil'TIFiCA-TE ore-01132011011. Patecpt No. 2i,-2l;a,'99h. July 15191;]..-

I 'me' J-ri It; is hqrebjcertifiedi'tha tfierrop appe'aira uth 'e fpglnte d ape cifigation of the atqove ngmbe'red patnt reqhjzting cdx r'g'ctiofi i l fr illov vis: Page 11., first page 5', second goluinn, 11:1 7, claimlO, 61; "catalyst". mad --:maas--.; and.

that the agid Lefi-tei'a Pajtenf sfiould' be rqa d with: this corrtion tho zzqin thaii the skid m ay c oriform re'qqrd ofthg: cage. lithe Patent Office.

Signed and aeled'this 26mm, offAu uat, A. i), 19in.

Henry 'Ar'adal (seal) Actihg Comii signer of Pat emits

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