US2500938A

US2500938A - Art of diluting steam or moisture formed or released during regeneration of contact material

Info

Publication number: US2500938A
Application number: US700568A
Authority: US
Inventors: James E Evans
Original assignee: Houdry Process Corp
Current assignee: Houdry Process Corp
Priority date: 1946-10-01
Filing date: 1946-10-01
Publication date: 1950-03-21
Anticipated expiration: 1967-03-21

Description

March 21, 1950 J. E. EVANS 2,500,938 ART OF DILUTING STEAM 0R MOISTURE FORMED 0R RELEASED DURING REGENERATION 0F CONTACT MATERIAL Filed Oct. 1, 1946,

' INVENTOR.

Patented Mar. 21, 1950 ART OF DILUTING STEAM OR MOISTURE FORMED OR RELEASED DURINGREGEN- ERATION OF CONTACT MATERIAL James E. Evans, Wallingford, Pa. assignor to Houdry Process Corporation, Wilmington, Del.,' a corporation of Delaware Application Octoberl, 1946, Serial No. 100,568

6 Claims.

My invention relates to .a process of controlling the efi'ect of steam or moisture formed or released during initial regeneration of contact material.

It is customary in the art for contact material having a deposite of carbonaceous material thereon to be admitted to a regenerating zone for regenerating purposes. Under certain conditions as hereinafter described, initial burning of the carbonaceous material in the aforesaid zone results in the production of a mixture of steam or moisture and-flue gases. When the contact material is catalytic in character, the presence of steam in high concentration with the evolved flue gases, during burning or regeneration as aforesaid, has an undesired aging eifect on catalytic activity. The regenerators in commercial use, of course, are operated at generally constant pressures, and therefore changes in steam concentration are in effect changes in the partial pressure of steam. It

has been found that the magnitude of the partial.

pressure of steam during regeneration of catalyst is an important cause of loss of catalytic activity, and it will be understood that in referring to steam concentrations herein, it is intended to denote such concentrations at generally constant pressure conditions and therefore, in effect, partial pressures of steam.

For reasons hereinafter noted, the carbonaceous material referred to, when-burned, may produce the described mixture of steam and flue gases and, hence, this material may properly be termed hydrocarbonaceous material. Thus, when bydrocarbon material is subjected to a cracking or,

other conversion operation in the presence .of catalytic contact material, the resulting carbonaceous deposit comprises hydrogen-rich components which, when subjected to initial burning In the process of my invention, contact ma terial of the character referred to above is passed through a regenerating zone or housing. In an area within and at the entrance end of said housing, a regenerating medium is engaged with the contact material to burn a portion of the carbonaceous material and, in so doing, there is produced a mixture of steam and the flue gases resulting from the burning operation, the concentration of the steam being relatively high. It

is a feature of the invention that, in suitable manner, an additional quantity of substantially steam-free diluting gases are added to the aforesaid mixture in order to substantially decrease the concentration of steam and thereby preserve catalyst activity.

More particularly, in' accordance with the in-' vention, streams of a regenerating medium are engaged with the contact material at the entrance. end of the regenerating zone or housing to burn a portionof the carbonaceous deposit in each of the 'engager zones. In the zone or area first traversed by the c'ontact'materia'l, the flue gasesresulting from combustion pass countercurrent with respect to the contact material and form a mixture with'the evolved or released steam. In the succeeding zone or area the flue gases resulting from combustion "also pass in countercurrent relation with respect to the contact material and are incorporated in said mix--' ture in order to--decrease'the concentration of steam therein; In the zone of the first engager,

thc'steamis evolved or released to substantial extent whereas the flue gases produced in the zone of the second engager are largely or substantially. free from steam. Hence, the flue gases last noted which theiinventionmay be practiced,- reference is to be had to the accompanyingydrawing in which: I

Figure 1 is an elevational view, partly in sec-- tionand partlybroken away, taken'on the line l-l of Fig. 2 and showing a regenerating housnc:

Fig. 2 is a horizontal sectional view, partly in plan, taken on the line- 2-2 of Fig. 1 lookingqin the direction of the arrows;

Figs. 3 and 4 are verticalsectional views, partly in elevatiomas viewed from the respective lines 1 3-3 and 4+4 of Fig. 2; and

Fig. 5 is a verticalsectional view, partly in elevation, showing a detailed feature of the invention.

I which; in horizontalcross-sectiorr'may be cir'- cular or of other suitable configuration. The

housing I defines a regenerating-zone utilizable for burning previously depositedcarbonaceous or other burnable material from contact ma" terial C which moves downwardly therethrough 5 under the influence of gravity, the contact material C being introduced into said housing I in suitable manner as by a plurality of spaced pipes 2 extending through the top housing wall.

The housing I, below the upper surface of the contact material C, has disposed therein a grid arrangement which may comprise a conduit 3 supported by said housing I, the respective opposite ends of said conduit 3 terminating interiorly and exteriorly oi the housing. As shown in Figs. 1-4 inc., the conduit 3 supports a plurality of channel members 4 which, in suitable spaced relation, extend horizontally from the respective opposite sides thereof,each channel member A, as shown in Figs. 1 and 3, being disposed in free communicating relation with the conduit 3 by way of passage 3a, formed within the latter. As disclosed in my pending application Serial No. 682,463, filed July 10, 1946, each of the conduits 3 supports a plurality of spaced vapor-passing tubes 5 and each of these tubes, in turn, supports one or more duplicate frusto-conical structures or inverted cup-shaped members 6, each tube 5 comprising a passage 5a for each cup-shaped member 6 carried thereby and each passage 5c opening into the space defined by the associated cup-shaped member 6 well above the lower surface thereof. As shown in Figs. 1, 3 and 4, the lower surface of each cup-- shaped member 6 defines a port or passage 6a utilizable as hereinafter described. 3 i

As shown on the drawing, a plurality of horizontal grid arrangements, which may be duplioates of the one described above, are supported by the housing I in spaced vertical relation.

In accordance with the invention the uppertwo Preferably, although not necessarily, the inlet ends of the engager conduits 3 are spaced to some extent from the outlet ends of the disengager conduits 3 in a direction extending exteriorly of and around thehousing I. manifoldingoperation and is otherwise convenient as will be understood.

Any suitable arrangement may be utilized for discharging the regenerated contact material from the housing I. grammatically indicated, a plurality of spaced horizontal tube sheets I, 8 and 9 may be secured to theinterior surface of the lower end'portion of the housing I, the extreme lower end portion of said housing I, preferably, being conical as illustrated. A plurality of suitably spaced tubes or pipes I0 open through and depend from each of the aforesaid tube sheets I, 8 and9. As known in the art, the tubes In on successively lower tube sheets progressively decrease in number and the diameter thereof progressively increases whereby the contact material passes through the lower conical end portion of the housing I and reaches 7 amain discharge pipe or conduit II which may be inclined as indicated in Fig. 1.

to the housing I by way of the pipes 2.

to the outlet ends of the respective pipes 2. As

This facilitates the the operation proceeds, contact material passes continuously through and from the housing I by way of the above described sets of tubes III which lead to the discharge pipe II. Simultaneously, contact material is admitted continuously to said housing I by way of the aforesaid pipes 2. Thus, within the housing I, there is a downwardly moving bed of contact material.

After admission to the housing I, the contact material C, initially, moves downwardly past the uppermost engager E. In so doing, some of the contact material, due to the presence of the cupshaped members 6, is deflected so that, while following circumferentially complete paths, it diverges from and then converges toward the respective longitudinal axes of said cup-shaped members 6. Thereafter, the contact material passes downwardly along the interior surface of the housing I and between the channel members 4 of said engager E.

In a manner similar to that described immediately above, the contact material C, during downward movement thereof, moves'past the succeeding engager E and thereafter, in succession, moves past the disengagers D and the remaining engagers E which may be positioned alternately as hereinbefore described.

As the operation proceeds, a stream of an oxidizing gaseous medium is supplied to each engager E by way of the associated conduit 3 and, simultaneously, a stream of hot flue gases is withdrawn from the top surface of the contact material and from each disengager D by way of the associated conduit 3.

At the uppermost engager E, the oxidizing gaseous medium passes from the channel members 4 from which a portion thereof passes upwardly through the tubes 5, thence through the respective tube passages 5a and, at the ports 6a of the respective cup-shaped members 6, is engaged with the contact material C. The remainder of the oxidizing medium which enters the channel members 4 passes therefrom directly into engagement with the contact material C and then moves upwardly therethrough where it joins "that portion of said oxidizing medium which is To this end and as dia-- engaged with the contact material at the cupshaped members Ii. The regenerating medium which is thus engaged with the contact material at the uppermost engager E passes upwardly 'therethrough and, at the upper surface thereof,

is disengaged as hot gases of combustion or flue gases which thereafter leave the housing I by way of one or more pipes I2, Fig. 1.

As regards that engager E which is disposed directly below the uppermost engager E, engagement of the regenerating medium with the contact material is substantially the same as described immediately above. Thus, from the cupshaped members 6 of this lower engager E and to some extent from the channel members 4 thereof, a stream of the regenerating medium is engaged with the contact material C and moves upwardly therethrough, the resulting gases of combustion or flue gases moving upwardly past the uppermost engager E and mixing with the medium which is engaged with the contact matei rial by said last named engager E. As hereinafter described, this is an important feature of the invention.

Usually, a portion of the oxidizing medium traversing the channel members 4 of the aforesaid lower engager E passes downwardly through the contact material from which it is disengaged, as hot gases of combustion, at the cupshaped members 8 of the uppermost. disengager D, these gases of combustiontmoving downwardly through the associated tubes 5, then into the,

directly below the uppermost disengager D, a

stream of the oxidizing gaseous medium traverses the conduit thereof and passes into the channel members t carried thereby, a part thereof moving downwardly through the contact material C toward the next lower disengager D, The remainder of the oxidizing gaseous medium last noted passes upwardly through the respective tubes 5 associated with said last named channel members s and, at the associated cup-shaped members 6, is engaged with the contact material through which it passes upwardly. The resulting hot gases of combustion enter the channel members t of the uppermost disengager D and pass from the housing i by way of the associated conduit 3.

With respect to the remaining engagers and disen 'agers which are disposed in the housing I, it will be understood that the operation thereof corresponds with that described above as regards engagement of the oxidizing gaseous medium with the contact material and disengagement of the resulting hot gases of combustion therefrom.

The contact material hereinbefore referred to may be of any suitable character as determined by the type of react-ion which is to be conducted in the zone which receives said contact material after passage thereof from the regenerating housing l. Thus, for example, in said reaction zone, hydrocarbon material may be subjected to a cracking or other conversion operation and, if so, the contact material may be catalytic in char actor, for example, it may be a synthetic type of cracking catalyst such as a silica-alumina catalyst or activated clay catalyst such as acid activated montmorillonite type clay. During such a conversion operation, a carbonaceous deposit comprisin hydrogen-rich componets. is formed on the catalystic contact material and, when the latter is returned to the housing l at a temperature sufiiciently high, such for example, as 800'F.-850 E, for burning of the carbonaceous deposit to be initiated when engaged by a regenerating medium supplied by the uppermost engager the hydrogen burns selectively and principally in the first burning zone or area as defined by said uppermost engager E with result-ant formation of flue gases together with steam or moisture. It is a feature of the invention that the hydrogen is thus burned under conditions such that the concentrations of steam in the flue gases is maintained: at a minimum or desired low value in the aforesaidfirst burning zone where, as stated, the principal formation of steam occurs. This is highly desirable because, as. stated, it has been found that steam or moisture, if at sufiiciently high partial pressure has a deleterious aging effect on catalyst activity particularly when the catalyst is at elevated temperature.

As hereinbefore stated, a stream of the regenerating medium is engaged with the contact material C for upward passage therethrough by that engager E which is disposed below the uppermost cngager E and this regenerating stream burns a portion of the carbonaceous deposit on said contact material immediately after engagement therewith; As this stream of material passes upwardly, it loses its oxidizing character to substantial extent and, when the. zone of said uppermost engager E is reached, the aforesaid stream of material is formed principally or largely from flue gases which mix with and dilute the stream of theregenerating mediumthat is engaged with the contact material C'by the uppermost engager E. This diluted gaseous mixture, containing steam or moisture evolved or withdrawn from the contactamaterial, passes upwardly therethrough in count'ercurrent relation and, in so doing, the flue gas content thereof increases progressively. Eventually, the steamr containin flue gases are disengaged from the contact material at theupper surface thereof and passed to a suitable destination by way of-the pipe or pipes l2.. Since under the conditions described it is important that the total pressure in the uppermost engager zone remain substantially constant, the pipe I2 i connectedwith the atmosphere or a zone of substantially constant pressure. In view of theforegoing, it-will be understood that a pressure differential is maintained between the lower engager E and the conduit ii in order to obtain countercurrent flow of the gases with respect to the contact material as described above.

As stated, the aforesaid hydrogen-rich components burn principally, accompanied by formation of steam, in the zone ofthe uppermost engager E. Hence, in the absence of dilution as aforesaid, the steam content would be as high as regards these gases which pass upwardly through the contact material after engagement therewith at said uppermost engager E, i. e., the steam partial pressure would be high. However, when the gases last named are diluted with substantially steam-free gases as described above; it results that the concentration of steam is reduced as regards all of the gases which move upwardly through the contact material from the zone of the uppermost engager E for disengagement at the upper surface of said contact material. This is desirable because preserving. catalyst activity.

Obviously, the dilution described above should be substantial and, therefore, the quantity of the regenerating medium admitted to the housing l by the above described lower engager E should be substantial. Although the invention is not to be so limited, it is desirable for the quantity of substantially steam-free gases to be at least approximately equal to the quantity of gases having high steam content with which they are mixed:

as described above. If so, the concentration of steam is reduced by approximately one-half as regards all of the gases. which are disengaged at the top surface of the contact material.

When the operation is as described above, the hydrogen-rich components. are largely ,or substantially burned from the contact material as the latter passes below the active zone of the uppermost engager E. Hence, the contact material, as it passes downwardly through the housing l below said zone, is largely or substantially free from steam or moisture. This is desirable for the reasons hereinbefore noted.

As stated above, the flue gases which pass upwardly from the zone of the described lower engager E are substantially free from steam. This necessarily follows by reason of the fact that, as

stated, the hydrogen-rich components of the carbonaceous deposit are largely or substantially time that the latter enters the active zone of the last named engager.

As disclosed, for example, in my pending application Serial No. 699,510, filed September 26, 1946, now abandoned, the contact material admitted to a regenerating housing may have high heat-absorbing capacity in order to prevent undue rise in temperature of said contact material during the regenerating operation. It will be understood, then, that the heat-absorbing capacity of the contact material C admitted to the housing I may be such that the heat liberated by combustion of the hydrogen-rich components of the carbonaceous material in the zone of the uppermost engager E is insuflicient to prevent the temperature of the contact material, while passing through said zone in the presence of the diluted steam-containing gases, from rising to an extent sufficient to damage said contact material. However, after removal of the steam as described, the temperature of the contact material, as the regenerating operation proceeds, may be elevated progressively to such extent as may be suitable or desirable.

Referring to Fig 5, I have shown the upper part of a regenerating housing I of the charcter illustrated in Fig. 1. In Fig. 5, a suitable coil or bank of tubes (3 is shown as disposed in the housing I above the uppermost engager E. The coil [3 is traversed by a suitable cooling medium such as water, vapors or equivalent and, when the contact material C passes downwardly in proximity thereto, heat is withdrawn from said contact material. An arrangement of this character may be utilized in case the heat-absorbing capacity of the contact material is insufficient to prevent undue temperature rise in the zone of the uppermost engager E. However, it shall be understood that my invention is not to be limited to a regenerating arrangement comprising the coil l3, or equivalent. The use of this coil is entirely optional as will be understood in view of the foregoing explanation.

As known in the art, steam may be admitted to the bottom of a reaction zone such as hereinbefore described to purge the contact material and, in so doing, eliminate the bulk of the hydrocarbons absorbed therein during the reaction operation, the heavy carbonaceous deposit being left on the contact material. During such a purging operation, there may be adsorption of steam or moisture by the contact material which, in this condition, passes toward and enters the regenerating housing I. It will be obvious that, in the zone of the uppermost engager E, such absorbed steam or moisture, if present, is eliminated or withdrawn from the contact material and mixed with flue gases in the same manner as hereinbefore described with respect to steam evolved from the hydrogen-rich components of the carbonaceous deposit on the contact material.

With respect to the invention as previously described, it is the flue gases resulting from combustion effected in the zone of that engager which is disposed below the uppermost engager that are utilized for decreasing the concentration of steam in the zone of said uppermost engager. From a broader aspect, however, the invention is not to be so limited. Thus, in any suitable manner, flue gases or other non-oxidizing gases which do not adversely affect catalyst activity may be introduced, for the purpose stated, into the zone of the uppermost engager E. If so, should it be suitable or desirable, a disengager rather than an engager may be disposed directly below the uppermost eng r.

In a preferred form of the invention, disengagement of the mixture of flue gases and steam is effected at the top surface of the contact material which fills the housing I. However, the invention is not to be thus limited since, if desired, a suitable disengager may be suitably located adjacent said top surface of the contact material and utilized for disengaging the aforesaid mixture and sending it from the housing I.

The previous description relates to a regenerating housing having at the upper end thereof, two engagers E which are utilizable in the manner described. The invention, however, is not to be so limited, Thus, if desired, any suitable number of engagers may be disposed in the housing I above the uppermost disengagers. Further, it will be understood that the engagers and disengagers may be arranged in any suitable manner with respect to each other otherwise than alternately as disclosed.

It shall be understood that the invention is not to be limited to engagers and disengagers of the form disclosed herein. Thus, if desired, the cupshaped members 6 may be omitted and each engaging and/or disengaging grid arrangement may be formed from a plurality of channels or other passage-forming members having suitable ports. However, engagers and disengagers of the character disclosed are preferred principally because they have high capacity for passing gases in either direction with respect to the contact material.

Ordinarily, carbonaceous or other burnable material is deposited interiorly of the pieces of contact material as well as on the surface thereof. References in this specification and in the appended claims relating in one manner or another to deposition of burnable deposit on the contact material shall be interpreted in view of the foregoing as meaning deposition of the burnable deposit on and/or in the pieces of contact material.

The invention has hereinbefo-re been described with respect to a preferred form thereof involving utilization of a stream of diluting gases to maintain, in the upper engager zone, the steam or moisture under partial pressure conditions such that catalyst activity is not adversely affected to substantial extent. However, the invention is not to be thus limited. Thus, aside from the aforesaid stream of diluting gases, disengagement of the flue gases from the top surface of the catalytic material in response to maintenance of a proper pressure differential may be suificient to cause the partial pressure of steam or moisture to be such that deterioration of catalyst activity is decreased to a marked or substantial extent.

While the invention has been described with respect to certain particular preferred axamples which give satisfactory results, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended, therefore, in the appended claims to cover all such changes and modifications.

I claim as my invention:

1. In the art of regenerating contact material having a deposit of hydrocarbonaceous material thereon, the process which comprises admitting such material to a regenerating zone for passage therethrough, engaging regenerating gases with the contact material to burn, in an area at the entrance end of said zone, a portion of the hydrocarbonaceous material with resultant pros duction from some of the admitted material of a mixture of steam and flue gases with the steam tending to be in substantial concentration, mixing a quantity of largely steam-free diluting gases with said mixture after said regenerating gases have initiated the described burning action whereby the concentration of steam in said mixture is reduced, and withdrawing the resulting mixture from said zone.

2. In the art of regenerating contact material having a deposit of hydrocarbonaceous material thereon, the process which comprises admitting such material to a regenerating zone for passage therethrough, engaging regenerating gases with the contact material to burn, in an area at the entrance end of said zone, a portion of the hydrocarbonaceous material with resultant production from some of the admitted material of a mixture of steam and flue gases with the steam tending to be in substantial concentration, adding to said mixture a quantity of largely steamfree flue gases resulting from combustion of additional carbonaceous material efiected in response to engagement of a second stream of regenerating gases with the contact material, and disengaging the final diluted mixture of steam and flue gases from the contact material after countercurrent flow therethrough.

3. In the art of regenerating contact material having a deposit of hydrocarbonaceous material thereon, the process which comprises admitting such material to a regenerating zone for downward passage therethrough, engaging a stream of regenerating gases with the contact material in an upper area of said zone to burn a portlon of the hydrocarbonaceous material with resultant production from some of the admitted material of a mixture of steam and flue gases with the steam tending to be in substantial concentration, engaging a second stream of regenerating gases with the contact material during passage thereof through a lower area of said zone to burn another portion of the carbonaceous material and produce a quantity of flue gases which are largely free from steam, and maintaining a pressure difierential in said zone to cause the flue gases from the lower area to pass upwardly to th upper area where they dilute said mixture during continued upward movement thereof.

4. In the art of regenerating contact material having a. deposit of hydrocarbonaceous material thereon, the process which comprises admitting such material to a regenerating zone for downward passage therethrough, engaging a stream of regenerating gases with the contact material in an upper area of said zone to burn a portion of the hydrocarbonaceous material with resultant production from some of the admitted material of a mixture of steam and flue gases with the steam tending to be in substantial concentration, engaging a second stream of regenerating gases with the contact material during passage thereof through a lower area of said zone to burn another portion of the carbonaceous material and produce a quantity of flue gases which are largely free from steam, maintaining a pressure differential in said zone to caus the flue gases from the lower area to pass upwardly to the upper area where they dilute said mixture during continued upward movement thereof, and disengaging said mixture from the contact material at the top surface thereof.

5. In the art of regenerating contact material having a deposit of hydrocarbonaceous material thereon, the process which comprises admitting such material to a regenerating zone for downward passage therethrough, engaging a stream of regenerating gases with the contact material in an upper area of said zone to burn a portion of the hydrocarbonaceous material with resultant elimination of a large portion of the hydrogen-rich components thereof and production of a mixture of steam and flue gases with the steam tending to be in substantial concentration, engaging a second stream of regenerating gases with the contact material durin passage thereof through av lower area of said zone to burn another portion of the carbonaceous material and produce a quantity of flue gases which are largely free from steam, maintaining a pressure differential in said zone to cause th flue gases from the lower area to pass upwardly to the upper area where they dilute said mixture during continued upward movement thereof, and disengaging said mixture from the contact material at the top surface thereof.

6. In the art of regenerating contact material having a deposit of burnable hydrocarbonaceous material thereon during downward movement of the contact material through a regenerating zone, the process which comprises passing such contact material into the regenerating zone under conditions such that all of the contact material bearing the aforesaid deposit as it is admitted to said regenerating zone has temperature at least as high as the ignition temperature of said burnable deposit, engaging a stream of regenerating gases with the contact material in an upper area of said zone to burn a portion of the hydrocarbonaceous material with resultant production from some of the admitted material of a mixture of steam and flue gases, maintaining a pressure differential in said zone to effect countercurrent flow of said mixture with respect to the descending contact material, disengaging said mixture from the contact material at the top surface thereof, and during continued down ward movement of the contact material through said regenerating zone, engaging other streams of regenerating gases with the contact material to burn additional carbonaceous material therefrom.

JAMES E. EVANS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,215,305 Voorhies Sept. 17, 1940 2,372,018 Ruthrufi Mar. 20, 1945 2,374,151 Wolk et al. Apr. 17, 1945 2,374,518 Wolk et a1 Apr. 24, 1945 2,416,214 Payne Feb. 18, 1947 2,419,245 Arveson Apr. 22, 1947 2,420,904 Boll May 20, 1947 2,429,545 Bergstrom Oct. 21, 1947 2,436,780 Simpson Feb. 24, 1948 2,438,261 Utterback Mar. 23, 1948 2,440,475 Jacomini Apr. 27, 1948 2,441,170 Rose et al. May 11, 1948

Claims

1. IN THE ART OF REGENERATING CONTACT MATERIAL HAVING A DEPOSIT OF HYDROCARBONACEOUS MATERIAL THEREON, THE PROCESS WHICH COMPRISES ADMITTING SUCH MATERIAL TO A REGENERATING ZONE FOR PASSAGE THERETHROUGH, ENGAGING REGENERATING GASES WITH THE CONTACT MATERIAL TO BURN, IN AN AREA AT THE ENTRANCE END OF SAID ZONE, A PORTION OF THE HYDROCARBONACEOUS MATERIAL WITH RESULTANT PRODUCTION FROM SOME OF THE ADMITTED MATERIAL OF A MIXTURE OF STEAM AND FLUE GASES WITH THE STEAM TENDING TO BE IN SUBSTANTIAL CONCENTRATION, MIXING A QUANTITY OF LARGELY STEAM-FREE DILUTING GASES WITH SAID MIXTURE AFTER SAID REGENERATING GASES HAVE INITIATED THE DESCRIBED BURING ACTION WHEREBY THE CONCENTRATION OF STEAM IN SAID