US2095265A - Use of contact masses - Google Patents

Description

Oct. 12, 1937. J. H. PEW

USE OF CONTACT MASSES Filed May 27, 1935 2 Sheets-Sheet l lOct. 12, 1937. J. H.1'PEw USE 0F CONTACT MASSE Filed May 27,' 41935 2 Sheets-Sheet 2 mi i N @Y du /WTO/PNEV.

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Patented Oct. l2, 1937' USE or con'rac'r Masses AApplication May 27,

9 Claims.

10 tact mass may be due to a chemical change in.

the mass, or to the tendency of the latter tol retain adsorbed in its pores some of the products `of the transforming operation, or to the gradual filling up of the pores by a deposit of contaminating material such as coke, alkali, sulphurous and tarry substances, etc., resulting from the transforming reaction. The present invention is applicable Where the 'loss in activity of the mass is due to the above or other causes. For reactivation, the conventional operation consists in purging the mass of converted and unconverted material, followed, in the case of actual deposition of contaminants, by solvent extraction ofthe deposits or by burning the same or by both solvents and combustion in sequence and in either order.

A second purging operation may follow the removal of deposits.

Heretofore for the purging of 'large converters containing very substantial amounts of solid contact material, it was deemed essential'to use a gaseous purging agent such as steam, for example, since only in this Way wasl it considered possible to insure penetration of the minute pores of the contact mass for the ejection of all charged materialtherefrom and to avoid pockets tending to retain material which might produce an explosion or other-dangerous condition at the beginning of regeneration by combustion or at the start of a` subsequent transforming run. There 4l) are'certain disadvantages to the use of an ejecting agent. In the first place, the operation is expensive due to the quantity of purging agent required to sweep out a large converter. In theA second place, unless the temperature kof the V purging agent is regulated very closely, undesirable temperature changes or variations are often eifected throughout the converter or in localized portions of the contact mass. In the third place, the ejecting agent is in most instances extraneous material and provision must be made for its production, storage, separation andv removal from l the system after it hasnserved its purpose.

One object of the invention is to produce a rapid and thorough removal of material in either gas-z '55 eous or liquid state from a chamber containing a i935, serial No. 23,533 (ci. 19e-52) contact mass without the use of a purging agent. Another object is to minimize for entirely to avoid temperature changes in the mass. Another object is to improve the speed and effectiveness of purging operations., Still another object is to make convenient and inexpensive disposal of the material recovered during the purging operation. Other objects will be apparent from the detailed description which follows.

The invention involves the application of a hig vacuum simultaneously at a multiplicity of points within and throughout the depth and cross section of the contact mass so as to be effective at once and to the same extent in every part of the mass. Contrary to expectations it was found that this method'of purging was much more efficient in the same or less time than the best previously used purging agent, such as steam, which in most instances is more strongly adsorbed by a catalytic mass than either the charge or the transformed product or both. Taking the best conditionsfor steam as a basis for comparison, my improved process of vacuum purging, when applied for the same length of time, recovers about 50% more material from the contact mass. This not only involves an important net gain, but there are other advantages: there is substantiallyno change in the temperature of the mass since no extraneous material is, fed. thereto; the operation is less expensive even when steam jets are used to produce the vacuum, for much less steam is needed than when the converter is purged with steam; there is no purging agent to be removed from the contact mass at the end of the vacuum purging operation. When the recovered material is wholly or partly in gaseous or vapor state, condensers may be arranged to assist in producing the vacuum. Either surface or barometric condensers may be used. The recovered material is sent back into the system preferably in advance of equipment for separatingout the desired product or products. lIn its preferred form the system is arranged to operate continuously with a plurality of converters connected up in parallel with each converter designed to be alternately on stream and in regeneration. u

Illustrative embodiments are shown in the ac-l companying drawings, in which:

Fig. 1 is a diagrammatic indication of one arrangement of apparatus for practising the invention; and u Fig. 2 is a similar View of part of the apparatus shown in Fig. 1 but disclosing.y one of the converters in section on an enlarged scale and indicating different apparatus for the vacuum purging operation.

fn the drawings, the feed, which may be any material to be converted or otherwise treated, such as hydrocarbon gases, vapors or liquids, is sent into feed line Si after heat exchange, if desired, with hot material from any source. The feed in line t may be sent through exchanger 30. for heat exchange with transfer line 5 leading to fractionator- 5, or it may bypass exchanger 3a in whole or in part by means of bypass 3b. Feed line 3 passes the feed to a heater 6 of any suitable or desired type, such as a pipe still, which raises the feed to the temperature of conversion and sends the same into alcharge line 'i having valved connections to a battery of catalytic converters il.

Any desired number of converters may be provided in the battery, but only two are shown, these being sufficient to indicate that the system can operate continuously with the converters alternately on stream and in regeneration. If more than two converters are provided, they may be arranged singly or in parallel, as desired, for the transforming operation, and singly or in parallel for the regenerating operation. One method of handling such a battery of converters is disclosed in the copending application of James W. Harrison and Thomas B. Prickett, Serial No. 612,086, filed May 18, 1932 which issued on February 25, 1936 as Patent No, 2,031,600. As indicated in Fig. 2, each converter is provided with a series of perforated outlet conduits which are uniformlyv distributed throughout the contact mass for the `withdrawa1 of converted material which is discharged from the converters through valved connections to transfer line d. For the best operation, it is preferable to distribute the charge uniformly allthrough the mass, and suchv preferred arrangement is illustrated in the sectional view of one of the converters in Fig. 2. As illustrated, each converter 0 is entirely enclosed by a thick layer of heat insulating material ila for the conservation of the desired temperature or temperatures,l andthe interior is divided, by ue sheets or partitions lib and 8c adjacent the ends thereof, into end manifolding chambers B and C and a central reaction chamber A which is lled with a catalytic or other contact mass M capable of effecting the desired transformation or treatment of the charge. Forthe conversion or modification of hydrocarbon gases, vapors and liquids, contact mass M may be activated hydrosilicate of alumina with or without other active materials such as finely divided metals or metallic oxides,the

mass being made up of bits, fragments or molded.

pieces, such as disclosed in the copending application of Eugene J. Houdry, Serial No. 600,581, led March 23, 1932. Perforated distributing conduits 8d, symmetrically. disposed within the contact mass M, extend through nue sheet 8b to establish communication between manifolding chamber B and reaction chamber A. Similarly, a second series of perforated outlet conduits 8e is provided, the conduits being embedded in contact mass M in uniform and symmetrical arrangement relative to each other and to conduits Bd and extending through the opposite ue sheet 8c to establish communication between reaction chamber A and manifolding chamber C after the manner disclosed in the co-pending application oi Eugene J. Houdry, Serial No. 611,362, filed May 14, 1932 which'issued on June 2, 1936 as Patent No. 2,042,468.

f For the regeneration of the contact mass after its activity has'been impaired by poisoning, as

aooaeet by the deposit therein and thereon of contaminants resulting from the transforming operation, the regenerating medium, such as an oxidizing agent when the regeneration is to be by combustion, is sent from lineI El through valved connections to one end of each of converters E, and the fumes are withdrawn from the opposite ends of the converters through suitable valved conne"- tions to line l0. Prior to regeneration, it is advisable or necessary to purge the lconverters of material left therein at the close of the transforming operation, both to avoid the danger of explosion when the regenerating medium is sent in, and also to avoid loss and destruction of the material still in the converters, which is partly converted and partly unconverted charge. In accordance with the present invention, this purging is effected by subjecting the converters to a high vacuum through suitable valved connections from each converter to vacuum line l l. By reason of the series of perforated outlet conduits te extending to all parts of the contact mass, the vacuum becomes available at once throughout the mass to substantially the same extent, producing a substantially complete removal of all of the charge remaining within the converters, whether converted or unconverted and whether absorbed or adsorbed Within the pores of the catalystic lmass M.

In Fig. 1, vacuum line it connects to a barometric condenser l2, water admitted by an inlet pipe i3 being utilized to condense the evacuated vapors which are washed down through barometric leg lll into a well l5 where separation of oil and water is effected. The oil, substantially at .atmospheric pressure, is removed from chamber l5 by suitable pumping means i6 and forced through line ll' into transfer line f3 in advance of fractionator il but beyond' heat exchanger 3a. The uncondensable or xed gases are removed from the top of condenser l2 through line I 8 by an evacuator i9 of any known or desired type, the gases being discharged thence through line 20 to be used as fuel or for other purposes.

Another method of applying vacuum to purge the'reaction chambers of 'the converters and of handling the recovered material is disclosed in Fig. 2, in which vacuum line ll leads to a surface condenser 22 which is preferably operated at a temperature of 225 to 250 F., with the result that the heavier oils boiling above 250 F. are condensed and collected in vessel 23, while the vapors and gases are withdrawn from vessel 23 through line 24 by the action of suitable evacuating equipment as, for example, a single or multistage steam jet 25. The mixed gases and' vapors pass thence into a second and final condenser 26 which discharges into a separator. 21 having an outlet 28 at the bottom for water, an outlet 29 at a higher level for the light oils, and a discharge conduit 30 near the top of 21 for the fixed gases. The heavy oils from the bottom of vessel 23 and the light oils from connection 29 may be removed separately or together. By preference, they are .both pumped into line l1 which returns this material, as in Fig. 1, to transfer line 4 in advance .of fractionator 5 but beyond exhanger 3m. Two

reforming of heavy naphtha to improve its antiknock characteristics, or for the refining 'and stabilizing of motor fuels of the gasoline type, i

since such light oils do not readily emulsify with water. When the material withdrawn by vacuum line Il comprises or contains heavier oils, as when converters 8 are used for the transformation of hydrocarbon distillates and residues of gas oil boiling range and higher, it is preferable to utilize separating. equipment of the" type disclosed in Fig. 2, since the heavier oils are rst separated out from the recovered material, while any water which was originally in the feed or which has been added to the feed as steam for the purpose of assisting in the transformation, is still kept in vapor phase. In this way, only the vapors of the verylight oils and steam (if present) are conducted, still in vapor phase,

from vessel 23, and a steam jet may be utilized for evacuation, since the light oils may then be separated out from the water in separator 2l without the formation of undesirable emulsions.

The composite stream of converted, partly converted and perhaps some unconverted material in transfer line 4, with the addition by line il of material recovered by the purging operation, is shown in the drawings as sent directly into fractionator 5 for division of the same into fractions by overhead, bottom, and side streams as may be desired, which fractions may be nished products or intended for further treatment. It is to be understood, however, that any other type of separating or subsequent treating equipment may bev provided, or that the composite stream may go directly to storage.

I claim as my invention:

1. In chemical reactions effected by or in the presence of a contact mass, the process of freeing the mass of liquid or gaseous material lcon-l tained therein or retained thereby after a period of operation which comprises subjecting the mass to a vacuum and making the Vacuum effective simultaneously and to substantially the same extent at a multiplicity of points distributed uniformly- Within and throughout the de th and cross section of the mass.

2. In chemical reactions effected by or in the presence of a contact mass, the process of recovering charged material from the mass at the end of a period of operation which comprises subjecting the mass to a high vacuum eective simultaneously and to substantially the same extent at a multiplicity of points throughout the interior of the niass and creating the vacuum partly by condensation of the material removed from the mass and partly by rapid removal of the uncondensed material. Y,

3. In a process of treatment or conversion o-f a uid material substantially in vapor phase by the actonof a body of contact mass capable of periodically being regenerated by passing a regeneration'fluid therethrough wherein the mass is alternately on-stream to effect the desired treatment or conversion and in regeneration to restore the mass to a state of increased activity, the step which comprises, intermediate the onstream and regeneration steps, applying a vacuum to the said Vbody of mass simultaneously at points throughout the same, so as to effect a rapid and -substantially complete purging therefrom of fluids contained within the said body of mass, in the absence of inert purging fluid to any substantial extent.

4. In the continuous transformation or treatment of material by the action of a contact mass disposed in a plurality of zones, the operating process which comprisesl feeding the charge to said zones in sequence under reaction conditions to producea continuous -stream` of transformed material, purging the contact mass in each zone A at the end of the transforming period by subjecting the mass to a vacuum and making the vacuum effective simultaneously and to substantially the same extent at a multiplicity of points distributed uniformly within and throughout the depth and cross section of the mass, and adding the material recovered by the purging operation to the continuous stream of transformed material. l

5. In the continuous transformation or treatment of material by the action of a contact mass disposed in a plurality of zones, the operating process which comprises .feeding the charge to said zones in sequence under reaction conditions to produce a continuous stream of transformed material, purging the contact mass in each zone at the end of the transforming period by subjecting the mass to a vacuum and making the vacuum effective simultaneously and to substantially the same extent at a multiplicity of points distributed uniformly within and throughout the depth and cross section of the mass, adding the material recovered by the purging operationV to the continuous stream of transformed material, and regenerating the 'contact mass in each zone after the purging operation in preparation for another transforming period by freeing the mass of contaminating deposits not remoived by the purging operation.

6. In a process of treatment orconversion of a combustible or explosive fluid material substantially in vapor phase by the action of a body of contact mass capable of periodically being regenerated by passing a combustion-supporting fluid therethrough, wherein the mass is alternately in conversion and in regeneration, the step which comprises, intermediate the conversio-n and regeneration steps, applying a Vacuum to the said body of4 mass at a plurality of points therewithin so as to veffect a rapid and substantially complete purging therefrom of fluids contained' Within the said body of mass, in the absence of an inert purging fluid to any substantial extent.

7. In a process of treatment or conversion of a combustible hydrocarbon iiuid material sub-v stantially in vapor phase by the action of a body lof contact mass capable'of periodically being recomplete purging therefrom of fluids contained within said body of mass, in the absence of an inert purging fluid to any substantial extent.

8. In a process oftreatment or conversion of a combustible hydrocarbon iiuid material by the action of a body of adsorptive contact mass capable of periodically being regenerated by passing a combustion-supporting regeneration fluid therethrough, wherein time mass is alternately in treatment or conversion. and in regeneration, the steps which comprise, following the conversion or treating step, applying a high vacuum simultaneously to a plurality of points throughout said body oi mass so as to effect a rapid and an at least substantially complete purging therefrom of hydrocarbon uid contained therein, in the absence of inert purging iluid to any substantial extent, then regenerating said mass by passing a combustion-supporting regenerating fluid thereinto, and when combustible deposits are Substantia1l1P eliminated, interrupting the passage of said combustion-supporting iiuid and applying a high vacuum to said body of mass, in the absence of inert purging fluid to any substantial extent so as to effect an at least substantially complete purg ing therefrom of regenerating uid contained therein, preliminary to another on-stream treating or conversion step, and repeating the above operations.

9. Apparatus for eiectinglchemical transformations comprising a battery of converters, each containing a contact mass capable of effecting the desired transformation and of regeneration, connections and controls for operating each of said converters alternately on stream and in regeneration and for selective control of the entire battery so that the apparatus may be operated ator intervening n circuit between said condensers for withdrawing the uncondensed material from one and discharging it into another of said condensers, and means for discharging said condensates into said transfer line.

JOI-IN HOWARD PEW.

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