US2161676A - Catalytic operation - Google Patents

Description

June 6, 1939. El J. HQUDRY 2,161,676

CATALYTIC OPERATION Filed Nov. 8, 1935 aaaaoa \oooncc Arran/fx A 'A Patented June 6,1939y ,v STATI-.fs

2,131,676 n l cA'rALY'rro orEnA'rloN v Eugene J. Houdry, Rosemont, Pa., assigner to Hendry Process Corporation, Dover, Del., a

poration of Delaware Appueauon November s, 19635,'sem1 No. 48,870 3 claims. (c1. 19e-52) This invention relates to catalysis and especially to the use of contact or catalytic masses in a cycle of alternate endothermic and-exothermic reactions. This cycle of operations is the normal 5 one when the contact mass acquires, during the desired treating or transforming reaction, which may be either endothermic or exothennic but is usually endothermic, a burnable or other` deposit which impairs or changes the reaction and which is subsequently removed in the alternate reaction to restore the contact mass to proper condition for resumption of the desired treating operation.

Heretofore such alternate reactions have been conducted at rather-widely different temperai tures, the difference being of the order of 200? F. or more. For example, many catalytic treating operations are conducted at 850 F. or below, while the temperature for a good regeneration by combustion of ccky, sulphurous, tarry and other burhable deposits in a reasonable length of time -.has required temperatures of the order of 1050 F. or more. Hence the necessary heating up and cooling down periods in the transition from one reaction to the other have unduly prolonged the regenerative operation as compared with the onstream operation and correspondingly adversely affected the economics of the cycle.

One object of the invention is to improve the operative cycle and to so conduct operations that the contact mass is utilized at high eiilciency thereby producing high yields of high quality products. Another object is to maintain va temperature balance between the reactions. Another object is to reduce materially or to obviate entirely both the interim periods between reactions and the supplying of heat from an outside or different source. Another object is to provide for the admission of all reactants at temperatures in or below the reaction range. lAnother object 4 is to maintain the contact mass at all times and during both reactions within a relatively narrow range of temperature. Still other objects will be apparent from the detailed description which -follows. I In one 'important aspect, the invention contemvplates relatively short reaction periods and the supplying of the greater part, if not all, of the heat requisite to the endothermic reactionv by the exothermic reaction. During ,one reaction, such as the endothermic, which is usually the important one from' a production standpoint, the contact mass is at a selected temperature or within a selected temperature range. During the subsequent exothermic reaction, which restores to the mass and to the apparatus adjacent thereto the as a reservoir for the storage of heat.

, heat given up during the previous endothermic ture of the contact mass is by controlling the .amount of bumable or other deposit laid down on the contact mass during the on-stream or treating operation. 'This in turn is affected, at least in part, by the length of the on-stream period and the rate of feed'of the charge, i. e., by the quantity of material subjected to the action oi' the contact mass. In practice, the best operation is to lay down on the contact mass during the on-stream period a deposit which is just sufllcient to bring the mass back to the selected operating temperature or to the proper end of the selected temperature range. If one reaction is much stronger than its companion reacy tion, some additional means may be required to maintain the contemplated heat balance, such as a circulated heat exchange or cooling medium' to remove the excess heat of a strong exotherlmic reaction and/or suitable adjustment of the temperature oi' the entering reactants.

In commercial operations involving the use of large masses of contact material, I have discovn ered that once the converter is at the proper temperature, all the heat required by the endothermic reaction can be made available from the alternate exothermic reaction. This is accomplished by regulating the reaction periods so as to utilize the contact mass and the metal of the converter In a short on-stream period, I have found that the re. actant iiuid can be fed at high rate and in large volume and produce little change in the temperature of the mass, at most a change of only `a few degrees.` In other words, during the entire onstream period the mass can be kept at optimum reaction temperature, and whatever loss of heat there may be, which loss may be large in terms of calories but scarcely noticeable in degrees due to the heat storage capacity of the contact mass and apparatus, is promptly restored by'the succeeding regenerative reaction.

While by no means restricted thereto, concrete p examples ofthe application of the operative cycle may betakengfromwertain catalytic operations for the conversion, transformation and treating of hydrocarbons including mineral oils in the production of high quality rened and marketable products such as hydrocarbon gases, gasoline, kerosene, naphtha, fuel oils, Diesel oil, etc.

lThe present invention is adapted to a number of operations in the temperature range of- 700 to 950l F., i. e., a temperature range of the order of 250 F. or less, including the transformation or cracking of heavier hydrocarbons in the gas oil boiling range, for example, to produce lower boiling hydrocarbons asin the gasoline boiling range. Another use is in the so-called reforming operation on naphthas, both light andheavy and both straight-run and cracked, to improve their anti-knock rating and better adapt them for use as motor fuel. Still another application is to the viscosity breaking of very heavy hydrocarbons including residual materials containing tars,

waxes, asphalt, etc.

The catalytic transforming or cracking ofhydrocarbons in the gas oil boiling range is advantageously effected in the temperature range of the order of 750 to 900 F., i. e., a temperature range of about 150 F. 'Ihe still'more limited and preferred range is 800 to 860 F. for virgin material, which range may be carried somewhat higher for`recharged material. For naphtha reforming, an advantageous temperature range is 850 to 950 F., for example with the more limited preferential range lying between 875 and 925 F. For viscosity breaking, a suitable temperature range is 700 to 900 F., with the more restricted preferential range lying between 790 and 850 F. z

Any catalyst capable of effecting the desired transformation, conversion or treatment'of the starting material may be used, but, inasmuch as the present invention contemplates relatively short reaction periods and regeneration of the contact mass in situ, the catalytic material should be in the form of lumps, fragments or molded pieces, as indicated, for example, in my copendiing application Serial No.-600,581, led Mar. 23, 1932, which issued as Patent No. 2,078,945 on May 4, 1937. Any metals or metallic compounds having the desired selective or adsorptive activity may be used and, if desired, these may be incorporated in finely divided form into or upon porous carriers which are themselves either catalytically active or inert. lIf the carriers are intended to be inert or relatively inert, they may be formed of china clay, pumice, fullers earth, diatomaceous earth, and like clayey materials. hand, the catalytic mass may be active or activated and comprise blends of silica and alumina produced by suitable acid or other chemical treatment of naturally occurring clays or blends of clays. A good silica to alumina ratio is ofthe order of 31/2z1, and the ratio may be carried as high as 4 or 41/2 1. For certain operations, metals or metallic` compounds may be combined with catalysts of the selected silica to alumina ratio, as, for example, for naphtha reforming, small percentages of vanadium, chromium, tungsten or molybdenum may be used. For mere viscosity breaking, `a silica-alumina catalyst may be utilized of very low activity and made especially porous by incorporation of vegetable matter which is later removed by oxidation, as disclosed and claimed in U. S. Patent No. 1,818,403, issued August 11, 1931, to Alfred Joseph. When viscosity breaking is to becombined with a certain degree of transforming or cracking, one method of preparing the contact material is to make a highly active blend of silica and alumina and then reduce the activity of the mass to the desired extent by suitable'heat or other treatment.

In commercial apparatus adaptable to the practice of the invention 'such as large convert"- ers containing several tons of catalyst wherein' On the other provision is made for distribution of reactants all through'the mass and removal of products from a multiplicity of pointswithin the mass, alarge number of conduits, certain of which are usually provided with ilns, are embedded in the contact mass, with the result that the catalyst, with the metallic-conduits and shell of the converter, provide a large reservoir for the storage of heat.

Converters-of this general type are'disclosed in Patents Nos. 1,987,905 and 1,987,911 issued to me and to T. B. Prickett, respectively, on Jan. 15, 1935. The metallic parts form good conductors of heat, but the catalytic mass, especially when composed of hydrosilicatesof alumina, is a poor conductor of heat. By utilizing the'converter for the storageV of heat and suitably controlling the duration and extent of the alternate endo.- thermic and exothermic reactions, it is possible to supply al1 the heat for the endothermic reactions by the exothermic reactions, and to keep the contact mass at or close to the optimum temperature or range of temperatures for the productive reaction which, in the instance of the operations on hydrocarbons heretofore referred to, is an endothermicreaction. For example, in the transformation or cracking of a virgin gas oil by a suitable silica-alumina catalyst at a temperature of 840 F. and at a feed rate of 1/1 (one liter of oil per hour to one liter of catalyst), the charge entering the'mass at 830 F., for example, it is possible to operate for ten minutes with a drop of only 6 to 8 degrees in the temperature of the mass, and up to 30 minutes with a drop of only 25 degrees. The period of the on-stream run is determined by the amount of coky or other burnable depositleft on the catalyst, which deposit should notbe allowed to ably under pressure, and at a temperature not above 800 F., but preferably considerably lower in order that the oxidizing m'edium may be utilized to carry off some or all of the excess heat of the exothermicreaction'. If; desired, other means, such as the circulation of a cooling medium, after the manner disclosed in co-pending application of myself and R. C. Lassiat, Serial No. 728,544, iiled June 1,1934, (which issued on May 4, 1937, as Patent No. 2,078,947), and. in

my copending application, Serial No. 6,291, filed n February 13, 1935 (which issued'on May 4, 1937,

as Patent No. 2,078,948) ,may be utilized to keep the temperature of the mass from going much above the optimum on-stream range, and to bring the temperature back quickly, if this rangel is exceeded. 'I'hus regeneration can be effected in approximately the period of the on-stream operation, and all of the heat lost in the preceding on-stream operation is restored, the cycle being continued as described. Since the heat for the on-stream or endothermic reaction is supplied by thealternate exothermic reaction, no heat need be given to the-mass by the entering stream of reactants. Hence the charge to be converted is sent into the mass'at a temperature not exceeding the optimum range and, if desired, 75

it may be below the optinnnn range. This is an important featur o! the invention, since there is no longer any necessity for heating the charge in excess of desired reaction temperatures. In

many catalytic operations, including the trans-f the yield and impairing the quality of the products.

For the reforming of straight run or cracked naphtha showing undesirable detonating characteristics, Vthe reforming to improve. the antiknock rating. is effected through the use of metals or metallic compounds, preferably of vanadium, chromium, tungsten and molybdenum,in dividually or combined, and supported upon inert or active carriers, as specified above. The temperatureoperating range is of the order of 850 to 950 F., and preferably between 875 and 925 A F. Due to storage of heat in the converter, during the exothermic regenerating reaction,` as heretofore described, an ample quantity :of heat for the endothermic or reforming reaction is provided, and the material to be reformedXcan be sent into the mass at temperatures of 850 F. and below, particularly if the selected optimum temperature for the reaction is set at the middle e of the preferential range, as aty about 900 F.

Short runs will be made to keep the carbon deposit low.

The viscosity breaking operation to convert hydrocarbon residues into domestic fuel oils, Diesel oils and cracking stock in the gas oil boiling range is catalytically effected in a temperature range of 700 to 900 F. and in the prefervrequire treatment toward the upper end of the preferential range. The contact masses, as

l previously described, are formed with large pores,

and,as compared with cracking catalysts, are relatively inert or of considerably reduced activity, dependent upon the amount of light products which it is desired to produce during .the viscosity breaking operation. Here again substantially the entire heat for the viscosity breaking or endothermic reaction can be stored in the mass for on-stream runs of short or moderate duration, and the charging material can be brought into the reaction zone at the lower end of the preferential range, as between 790 and 830 F. If the charge is brought into the converter Vat any higher temperature, it will be for the sole purpose of keeping the charge in vapor phase and more than 50% of the heat of the reaction will still b'e supplied by the stored-up heat in the contact mass. The operation is conducted so as to produce a small burnable deposit on the catalyst to avoid difliculties in taking care' of the excess heat of the strong exothermic regenerative `reaction.

thermal cracking, which is highly deleterious to a catalytic operation. -Thermal cracking, even in small degree, has a very adverse effectv upon the yield and qualityof the products. Since this can now be entirely `avoided, it is possible to conduct a truly catalytic reaction. The permissive'low temperature of the charge leads to wide l latitudeln other operating conditions. Almost any feed rate can be selected, for exampleas low as ifi-9 (one liter of oil per hour to l0 liters of catalyst) or as high as 1%. Also, any pressure condition can be utilized,subatmospheric, atmospheric, or superatmospherlc. Hence the best operating conditions can be selected for the production of both high yield and vhigh quality.l

When regeneration of the contact mass is by oxidation, it is essential that the deposit burn freelyy within the selected temperature range. To insure this, it is desirable that the contact mass contain an oxidation promoter, such as manganese in small amount as disclosed in my copending application Serial No. 35,101, filed August ,7, 1935 (which issued on May 4, 1937, as Patent No. 2,078,951), unless some other material capable of producing this effect is already present.

Apparatus in which the improved cycle of the present invention may be practised has already been disclosed in my copending application Serial No. 604,997, filed April 13, 1932 (which issued on March 16, 1937, as Patent No.'2,073,638), in the previously identified patents to T. -B. Prickett and myself, and in the aforesaid copending applications Serial Nos. 728,544 (Patent No. 2,078,947) and 6,291 (Patent No. 2,078,948), also in my copending application Serial No. 12,564, filed March 23, 1935 (which issued on May 4, 1937, as Patent No. 2,078,949). However, the invention is not primarily a matter of apparatus but rather a process of controlling certainoperations'. It is applicable to many forms of apparatus in addition to those mentioned above, but not to the same extent. For example, the more emcient the heat exchange between entering reactants and the contact mass, the lower the temperature at which the reactants may be fed to the converter. Moreover, if the converter provides for the circulation of an independent heat exchange mediumadapted to carryawayV heat, a larger burnable deposit can be laid down in the mass during'the .on-stream reaction, since there is provision for removing the' excess heat of a more intense regenerating reaction.

For one specific illustration of apparatus, reference may be had to the accompanying drawing, the single gure of which is a vertical sectional view of acatalytic converter with certain parts shown in elevation or partly in elevation chambers A and B and a centrally located reaction chamber C by perforated partitions or flue sheets `5 and 6. Fluid reactantsl for either endothermic or exothermic reactions supplied selectively by valved lines Il or 22 may pass through TIB to enter manifolding chamber A and be distributed uniformly throughout the depth and cross section of contact mass or catalyst M, Adisposed in reaction chamber C, by means of a series of distributing members or perforated conduits 1 (which may or may not be of nested construction) while fluid. reaction products are simultaneously vented lfrom a plurality of points in mass M into a series of perforated outlet ooncoV , duits 8. The fluid reaction prodncts are disespecially to remove heattherefrom during exothermicreaction periods or during a portion of each or all thereof. Manifolds il and Ila in nested relation supply .the heat exchange fluid toand remove thisfiuid from conduits 0 'and 8a.

Y IAr'xontinuously fresh supply of the heat .exchange cycle wherein the contact mass is kept at all times uid may be or the duid may be recircuisted .through conduits s vund so and aanname Bystem,jas. for example, the circuits desei-lbed in the aforesaid Patent No. 2,073,947, may

beiem'plyed, as desired. HWhile the present invention contemplates a within a selected temperature range, it is to be .understood that itis not tobe limited strictly to this-condition. To insure adequate storage j of heat in the contact mm and adjacent apparatus. especially when the productive reaction is to be continued for a rather long period, .it is at times desirable to carry the regeneration temperatures for a part of the regenerative reaction s outside or above the specified range. This may 1 also be done from time to time, if desired, to effeet a very complete or thorough regeneration of the contact mass. All such variations and temporary modifications are within the spirit and.`

scope of the present invention. d

I claim as my invention:

1. Inthe conversion of high boiling hydrocarbon iluids to produce lower boiling hydrocarbon including gasoline, involving the use` of a converter containing a'solid adsor-ptive contact material or catalytic mass in alternate periods of endothermic reaction, durin which combustible g Aevlr-sorptive silicious contact material or catalyst in deposits accumulate o`n .or within said'mass, and of regeneration in place by combustione! said deposits, the 'steps of process which comprise maintaining the catalytic mass `or contact mate rial within a predetermined and optimum temperature range of not more than 250 P. which lies below 950 F. throughout each cycle of op--` eration; during an on-stream or reaction period verter and in contact with said catalytic mass, so that said catalytic mass drops within the afore- .said range during the on-stream period due toheat absorbed by the endothermic conversion of Y hydrocarbons; during an alternate period 'of regeneration passing an oxygen-containing regen-` Y erating fluid into said converter and in contact with said catalytic vmass to remove contaminants therefrom so that thesaid mass rises within the aforesaid range during the regenerating period` due to heat evolved by the exothermicdregeneration; limiting the duration of said on-stream or reaction period so that the accumulated comon-stream period and of the period of regeneration, thereby to provide aneilicient cyclic operation for the conversion of hydrocarbons in the presence of a contact material and for regeneration of said contact material in place. l

2. In processes for utilizing a converter containing an adsorptive catalytic mass alternately for the endothermic conversion of carbonaceous fluids which leave combustible contaminants on or within the mass and for regeneration of the mass in place by combustion of such contaminants, the steps of maintaining the converter and catalytic mass within a predetermined temperature range of not more than 150 F. which is mainly below 950 F. during both conversion and regeneration periods, during the 'conversion periods passing heated fluid reactants into said converter and into contact with said catalytic massl said fluid reactants being heated so as to avoid thermal cracking prior to introduction into said converter to such temperature adjacent the lower end oi said range that the catalytic mass and converter substantially supply the endothermic heat of reaction and their temperatures fall within the aforesaid range, during each alternate exothermic regenl eration period passing a regenerating medium into said converter and into contact with said mass so as to burn away combustible deposits and to f cause the temperatures of said converter and of said mass to ris'e within the aforesaid range, and limiting the duration of the conversion, periods so as to control the combustible contaminants deposited on or within said mass to an.

' temperatures of the catalytic mass increase during one period of the cycle and decrease during the other period thereof.

v 3. In the' cracking of reactant hydrocarbons 1 boiling to substantial extent above the gasoline boiling range to produce therefrom /high antiknock low boiling motor fuels including gasoline involving the use of a converter containing an adrecurring cycles, each of alternate periods of enothermic transformation or cracking of hydrobons land of regeneration of the contact material in place by combustion of burnable contaminants deposited thereon during a preceding transformation period, the steps of process which comprise maintaining the 'contact material during a predomlnantproportion of each cycle of operation within a 4predetermined temperature range which is above '150 and below 950 F.;

during each on-stream or transformation period admitting'reactant hydrocarbons into' contact with the catalyst or contact material at such a temperature approximating the aforesaid range that thermal cracking is avoided prior to contact withl the catalyst and that the said catalyst and converter supply endothermic heat of reaction and their temperatures fall within the aforesaid material or catalyst 'being decreasing temperatures which are completely within the aforesaid :gieen 5f `mmm throughout substantially the entirety or yref; y y p period when vtheteniperature of the. catalyst il spective individual on-stream periods antitesiv peratures during regeneration beingy rising peratures which are within the aforesaid raxizvcfV throughout the predominant proportion 'of the: duration of respective individuailoregeneration" periods, and circulating a heat exchange ii'uidin f heat exchange relation with but out of contact with said catalyst or contact material particu-" liirlyv duringv any. portion of each regalieration aboveV the aforesaid ranseg-fso as bocontroi the temperature ofA catalyst Yand quickly to restore it to a 'temperature within the aforesaid range, thereby to provide an emcient cyclic operation for the trari'formation of hydrocarbons in the presence of a4 contaetimateriai.

*Y `liUGlNl J. HOUDRY.

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