Патент USA US2283832код для вставки
May19, 1942. K Í l _ Y c. l.. THOMAS - ?/ 2,283,832 <AND EXOTHERMIC CATALYTIC REACTIONS CONTROL I Filmfan. 9, 1940 .ì 2 Vy' È . Ill’rl’l 3552-21 1111111; ". / V » ‘ _*- 32,265 " HEATER? ' Patented May 19, 1942 ' ` 2,283,832 UNITED STAT ES v 'PATENT OFFICE / _ ' rnEaMrcoA'raLrrrc aaaorroNs Charles L. 'l‘liomaav Chicago, lll., assignor` to Uni ` versal 'Oil Products Company, Chicago, lll., a v corporation of Delaware . - 1 ' application' Febreary 9. 1_940, serial No. :5,113,098 mits-1)' ï The invention particularly relates to an im proved method and means of controlling the place for `a substantial body or pool of liquid in which,- according to conventional practice, said temperature ofsimultaneously conducted endo' thermic and exothermicl reactions. whereby heat tubes or other elements are immersed or bathed. ‘_ Preferably, in accordance' with the provisions ’ >of the present invention, any of the liquid heat liberated in the exothermic step is advantageous' ly supplied to the endothermic step through the ' transfer' medium which remains -unvaporized in ñowing> over the surface'of the catalyst contain >er in which the exothermic reaction is taking p1ace,»as well as the condensate which._forn_is on medium of vliquid which is vaporized by'indirect heat exchange with-the materials in .the exo thermic relation zone »and condensed _by indirect heat exchange with' the materials in the endo t ~ thermic reaction zone. the surface ofthe catalyst 'container in which ro ’the endothermic reaction is'taking place, i‘lows . The usual method of controlling temperatures from the lower portion of the reactor to> a small in l simultaneously conducted endothermic and " accumulating drum or the like wherefrom it is' - pumped back to the reactor and sprayed or oth exothermic reactions, wherein a vaporizing and condensing fluid is employed‘as the „heat trans-~ :l54 erwise distributed overïthe surface of the catalyst fer medium, is to employ separate interconnected ' reactors of-the heat exchanger type each’contain- ' 'container in which Jthe exothermic reaction is >taking place.` Thus, when-the operation is dis continued for anyv reason and the circulatingl ing tubular- elements or'the `like'wherein the de lpump is stopped, the liquid drains to the accu sired conversion reaction takes place, the tubular elements wherein the exothermic reaction is tak, 20, mulator, leaving the reactor substantially dry. This is particularly- advantageous when a heat ing piace being .disposed in a body of liquid which is vaporized by the heat evolved. the vapors thus-- - transfer fiuidwhich solidifies at normal tempera ture is employed, since, by the elimination of a generated being conducted to the other reactor body of such'material in the reactor,- its solidifi wherein they are condensed by contact with the tubular elements wherein the endothermic re action is taking place and the condensed liquid being returned therefrom to the -body of liquid cation therein and the attendant diillculties are. , ' obviated. Thus, the -reactor may be Areadily _opened for inspection, repair or the like, after the operationisdiscontinued andthe> apparatus in the >first reactor, ' is cooled, and in order to melt the heat trans -,The present invention obviates the use of sep arate reactors inv this type of system'by dispos-y 30 fer material in preparation for starting the op ing the tubes or other elements wherein the en ' _' eration, it is only necessary to supply ,-heat ex dothermic and exothermic reactions occur within- ' ternally. or otherwise. ,to vthe relatively small. a common shell` or housing comprising a single re- ' . mass of such material in the accumulator.. The invention is adapted to be advantageously actor and spraying or washing the surface of the utilized for controlling temperatures in awide ' zone in which the exothermic reaction is taking.` ' variety of catalytically promoted orcatalytically place with the heat transfer liquid which is there by vaporized and condenses on the surface ofthe .' retarded reactions and although, _as previously explained, it is particularly advantageous >as ap zone in which the endotherniic reaction is taking plied to simultaneously conducted endothermic place. This also obviates maintaining a substan tial body or a pool of liquid about the zone where' 40 `and exothermic reactions of the class in which the zones ofxendothermic and exothermiereac lin the exothermic reaction occurs and is par tion are periodically shifted, it is not limited to ticularly advantageous in operations wherein the catalytic reactions so long as- the operation in, i -zones of endothermic and exothermic reactions volves the transfer of heat from a zone wherein are periodically shifted from one set of tubes to another, since the shift may be accomplished 45 it is liberated' to one in which it is absorbed without'transferring a substantial body or pool i through the medium of a vaporlzing and condens ing vfluid employed in the- manner herein pro -of liquid from one reactor. to another. ~Another advantage results from the fact that, The most common example of an operation of with the improved 'apparatus and mode of opera-> tion herein provided, the quantity of heat trans 50 the general type in’which the zones' of endo thermic and exot-hermic reaction are periodical-fer fluid required for an installation of any given capacity is materiallytreducedI by virtue of the t ly shifted, is one in which the activity of a mass of catalytic material employed to promote or re, ` substitution of a sheet orillm of4 evaporating tard one` of the reactions decreases with such liquid on the surface of the tubes or other ele ments wherein the exothermic reaction . takes 55 rapidity and to such an 'extent that frequent 2,283,832 ' 2 and in which the improved process of the inven periodic reviviñcation for reactivation of the catalyst is required. This occurs in such endo thermic processes as the catalytic cracking and tion may be conducted. The shell of the re actor is illustrated in cross-section and other portions of the apparatus are shown in elevation. catalytic dehydrogenation of hydrocarbons, wherein heavy carbonaceous conversion products 5 Referring to the drawing, the outer shell I deposit on and foul the surface of the catalyst particles, reactivation of the catalyst being an exothermic reaction and involving burning of the of the reactor. in the particular case here illus trated, is cylindrical in form and is provided with an upper head 2 and a lower head1. ’I'he in carbonaceous materials from the catalyst'in a terior of the shell is divided into compartments, stream of hot oxidizing gas. The catalytic Í 10 A-and A', B and B',’C, D and D' by means of polymerization of hydrocarbons and catalytic the horizontal partitions l and 5, the lower sub stantially cone-shaped partition 6 and the ver hydrogenation are examples of other exothermic' reactions which may comprise the exothermic tical partitions 'I- and 8. An inlet nozzle 9 in the step of a process embodying the features provided VUpper head 2 communicates with compartment by the invention and in such instances the en 15 A and compartments A and D communicate dothermic step may comprise, forA example, pre through the tubular elements I0 extending there heating of the reactants forl the exothermic step, ' between, an outlet nozzle II in the lower the generation of steam, the heating or vaporiza head 3 - communicating with compartment D. On the opposite side of a vertical planepassing tion of oil or any other fluid for any desired pur pose or it may comprise a pyrolytic or catalytic 20 through partitions] and 8, an inlet nozzle S'in conversion reaction such as thermal or catalytic the upper head communicates with compartment cracking, dehydrogenation, isomerization, cy -A' and the latter communicates with compart clization or the like or a combination of such op ' ment D' through the tubular elements I0’ ex erations. These examples are typical of conver sion operations encountered in modern hydro carbon oil renning. The invention will find fur ther application in many other chemical indus tending therebetween, an outlet nozzle II' com municating with compartment D' being provided in the lower head 3. tries andgits broad features are in no way limited to the s'peciilc reactions involved. ' Any heat transfer medium may be employedl which will substantially vaporize at 'a tempera ad ture within the range of that desired for the ex othermic reaction and 'which will be substantial ly condensed at a temperature within the range suitable for conducting the endothermic reaction. Atmospheric or substantially atmospheric pres » Compartments B and B’ each communicate with compartment: C through a plurality of suit as able orifices or spray nozzles, such` as indicated, for example, at I2, which are provided in parti tion 5 about each of the tubular elements I0 and I Il'. The purpose of these openings l2 is to spray liquid from zone B over the surface of tubes Il l or the liquid from ‘zone B' over the surface of tubes III'. whichever tubes comprise thezone in which the exothermic reaction is taking place, as sure may be employed in the zone wherein vap will be later explained. orization and condensation of the heat transfer medium employed occurs, or, when required, the Vapors generated on> the surface of the zone in which the exothermic reaction is »taking place ` i ' boilingpoint of the heat transfer «medium em are totally or partially condensed on the surface , ployed may _be modified by the use of . sub-at of the zone in which the endothermic reaction is , mospheric-or superatmospheric pressure in this zone. The specific heat transfer medium em taking piace. Thus, an emclent transfer of heat4 from the exothennlc to the endothermic reaction ployed in any given case may be selected to ful ' ñll the above requirements and may range from relatively low-boiling liquids or readily condensi ’ 1s obtained. 45 1 . Condensate formed on the surface of the zone in which the _endothermic reaction is taking place islremoved from the lower portion of the water, alcohol and the like through the many reactor through line I3, together with any quan heavier liquids such as hydrocarbon oils, aliphatic tity of vapors generally in excess of those re ~ and aromatic ethers and glycols to and includ vto quired to supply the desired heat to the endo# ing normally solid materials such as molten salts thermic reaction.- When only liquid condensate and mixtures thereof (eutectic or otherwise) low` is thus removed from the lower portion of the ' melting point metals and alloys. Wherever pos reactor, it may be supplied from line _I3 4through sible, the‘heat> transfer medium selected should> line I4, valve I 5 and line I9 to accumulator 2li or> be non-corrosive and otherwise chemically inert 55 it may be passed, all or inl part, from line I3 to metals which are not injured by and exert through valve IB, cooler I 1, line I 8 and valve I9 ‘ ble normally gaseous materials such as propane, no detrimental effect on the endothermic and ex to theaccumulator. In case vapors are with-H othermic reactions involved but, when no heat drawn with the liquid from the reactonthe mix transfer medium which fulfills all of these re ture is preferably passed, as' above described, quirements is available,- the shell and tubular 60 through cooler I1 to the accumulator. elements or catalyst containers of the reactors ' The function of coolerl I‘I is to 4condense any ‘ may be constructed of a metal or an alloy which .vaporous components of» the convective medium - is not adversely effected by a heat transfer medi _ removed from the reactor and to reduce the um which possesses the required physical char temperature of the convective medium, when acteristics, while the tubes or other elements of 65 this is required. It may be of any suitable con the reactor, which form the zones wherein'thc ventional form and, in the particular case here endothermic and exothermic reactions occur, illustrated, comprises a heat exchanger to which ' may be coated or lined `with another suitable suitable cooling fluid is directed through line metal, alloy or other protective coating which `2I, passes through the cooler in indirect heat does not; adversely affect and is not adversely 70 exchange relation with the >convective medium affected by the _reactants and the catalyst,`in case and is removedtherefrom through line 22. Thus. a catalyst is employed. only liquid is collected in the accumulator and' The accompanying drawing diagrammatically is preferably kept at such a temperature that illustrates one specific form of apparatus em ' it may be returned therefrom to the reactor and bodying the features provided by the invention 75 sprayed over the surface of the ‘tubularelements . - 3 2,983,832 ` in which the exothermic reaction is taking fplace l at a temperature close to its vaporization' point, line 2i, although this is not illustrated in the allowing for radiation losses’ froml the„circulating equipment, This temperature adjustment may be accomplished'by the operation of cooler -Theftubes Il andthe tubes Il' comprise sep- ' arate zones in which contact- material such'as a drawing. V ` ~ q ¢ 'l ' ‘ `catalyst for promoting the de's'ziredv reaction may bev disposed and in which the'desired‘fendother- ‘ ' I1 and valve l5 in by-p'assq-line Hf or by adjust ` ment of the amount and/or temperature of 'cool ing fluid passed through cooler I1. ` ‘ , j mic reaction and’exothermic reviviilcation of the catalyst may be alternately conducted. Any suit , able means of conventional form maybeïem ' Liquid from accumulator 20> is directed through line 23 to pump 24 wherefrom itis fed through, 10 ployed for switching the ilow of the stream "of line 25 and’it may ordinarily be _directedwthere reactants and reactivating gasesl with respect to from, all or in part, through line `28> and Avalve 21 back to zone B or to zone'lB’y without addi tional heating or cooling. However, in case ad ditional heating of the recirculated convective partially spent revivifying gases from zones D zones A and A’ and the separate tube banks and , for diverting the outgoing reaction products and « and D', each to the desired subsequent equip ment. liquid is required to obtain a closer approach to The specific form of such> means -'em ployed do not Jconstitute part of the invention its vaporization point lnzones y13 and B', with out allowing any appreciable quantity of va pors to collect in the accumulator, all or a- regu Vand since several suitable forms are nowïwell known in the industry they lare not'illustrated lated portion of the convective `liquid-'is _recir 20 culated to zones B and B' through heater 2l by manipulatingl valve 21 in line 2t, valve 29 in the’drawlng. i ‘ ' ~ _It will be apparent from the _above that -the invention takes advantage'of the latent heat of vaporlzation and the latentfheat of` condensa- tion. of a circulating heat- transfer fluid for con- " in line 25 and'valve 23 in line'32. "From the .junction oflines 32 and 28,jthe reheated or u_n reheated liquid from‘accumulator 20 is direct 25 trolling `the temperature of simultaneously con ducted endothermic and exothermic reactionsiand ~ed through line 34 and valve 35 to zo'n'e'B orl through line 3l' and A35' to zone> B' and -~from zone B -or zone B', as lthe case- may. be, itis l again caused to pass' 4over the surface of the vtubular elements in which the exothermic reac 30 'tionis taking place. - ` ' ~ that, with the apparatus provided, this may be accomplished with a relatively small quantity ' of heat transfer-'fluid and ¿without maintaining a substantial bo'dy or pool of vaporizing heat transfer liquid about the zone in which the ex - Heater 28 maybe of any suitable conventional ' 'othermic reaction is taking place, thereby accom form and, in the particular _case here illustrated, - 1 plishing the improvements mentioned prior. to comprises a heating coil 30 disposed in a s_uit the description' of` the'drawing. -Furthermore, to 'generate hot combustion gases4 inv-the -i'ur- 'A exothermic reaction are periodically ‘shifted and able furnace 3I to which a regulated quantity 35.' the process adapts‘itself-to operations of the .of fuel and air are, supplied throughburner 3l ' type in whichv the zones ’of .endothermic and- all of the desirable features'of-the‘processfmay beA accomplished in an apparatus oi'rrelativellfv nace and supply the desired quantity of_- heat ` therefrom to the convective fluid passing through coil 30. . Instead of ,serving as a tempering‘zone where simple form. ~ .` .It _wm be understood, of course, that the se# in any required small additional quantity of heat - > companying 4drawing illustrates only one of the may besupplied to the convective liquid recircu- ' .many specific forms of apparatus in which the » improved process provided bythe invention may ' heater28 may, in accordance with another mode .45 be conducted and should, therefore, not be con strued as a limitation. For example, insteadv of of operation of 'the process, serve as a zone wherein a regulated quantityoi the recycled l comprising tubes, the zone- in which the endo ' thermic and exothermic reactions occur'may'be convective liquid may beA revaporized >at sub _stantially the temperature prevailing'in space y formed between spaced metallic 'sheets 'or plates C of the reactor and supplied to the latter zonel 50i of any desired contour and any other well known to augment, to any ldesired degree, the quantity> ' means of spraying or otherwise distributing the lated from the accumulator to zones B and B', - the surface of the zone in which the exothermic' . heat transfer liquid over >the surface upon which it is vaporized by heat evolved in the exothermic reaction is Ataking place. 'When this -mode of reaction may be- employed within the scope of the ' through valve 29 inline 25 to> and'through heat down-flow may becemployed within .the "zones . of vapors evolvedfrom the convective liquid on ' ’operation is employed, regulated quantities of; 55 -invention in place of the specific means illus-I the liquid from- accumulator 20 are directed Y trated in the,y drawing. Also, -either up-flow or wherein _the endothermic- and exothermic reac tions occur and the direction of flow isnot neces 'which they are thence directed through line 22, line 31. and valve 38 into space C of the reactor. ' ' sarily-the‘, same in both zones. For example, an ing' coil 30 wherein they are vaporized andl from> “wherein they commingle with thevap'ors evolved endothermic reaction such as dehydrogenation, _ ' from> the convective fluid inthis zone and, by v catalytic cracking or the likemay be»accom- - condensation on the surface of the tubes in which plished by passing a stream of heated hydrocar-` ` bons upwardly through the zone of le'ndotherrriic they endothermic reaction lis takingplace, sup ply to the latter any-heat required for conduct 65 reaction in contact with a bed of catalytic mate-l ing-'the endothermic reaction in excess of that ~ -rial disposed therein, countercurrent to the di' .' evolved in the exothermic reaction.' ' »' -In caseA heater 28 is utilizedv inthe manner last described and it is also necessary to supply some additionalheat to the convective liquid recirculated from Athe accumulator to zones B and B', a. separate heater of any conventional _ form suitable for supplying the required addi rectlon of flow of the tllmor sheet of condensed - e» heat transfer fluid flowing downward »over the outer surface of the walls of this zone, while the catalytic material in the zonefof exothermic re action is being reactivated by passing a stream of hot oxygen-containing gases downwardly through this zone in contact with the catalyst, concurrent to the film or sheet of vaporizing tional heatv to the convective liquid recirculated to the zones B and B' ‘is preferably provided in 75 heat transfer ñuid flowing downwardly over the 4 ' 2,288,832 mercury, we lind that only about 196 pounds per exterior surface of the walls ofv this zone,` or, hour of mercury vapor need be condensed on the surface' of the tubes in which the cracking when desired, this procedure may be exactly re versed or concurrent or countercurrentñow, with reaction is taking place to satisfy the heat re quirements `(i. e., 25g000 divided by 127.5 `equals respect to the‘illms `or sheets of heat transfer fluid ilowing downwardly over the surface of the 196+). „ Therefore, no liquid/mercuryis allowed walls of theexothermic and endothermic 4reac `tion zones may be employed in both zones. to accumulate in the` reactor` and approximately As 31 pounds per hour of mercury vapor is passed applied to the apparatus illustrated in the draw with the liquid mercury from the reactor through ing, this means that nozzles Il and Il' may be employed as inlet rather than outlet connections, 10. the _condenser tothe accumulator,- the mixture of mercury vapor and liquid being cooled in the while` nozzles Á9 and 9' are employed as outlet condenser to such a temperature that, allowing rather than inlet connections or their usel as for radiation losses in the recirculating lines, the inlet and outlet connections may be alternated. resulting liquid mercury is returned to the reactor As an example of one speciiic operation of the> at a temperature of about 980° F. ' process provided by the invention as applied ‘tov The figure above given for the pounds of mer `the catalytic cracking of Ahydrocarbon oil (the( l cury circulated through" the system per 100 endothermic reaction) with .periodic vreactivation Vpounds of oil treated per hour is not to be taken of the catalyst (the exothermic reaction)„as it as indicative of the quantity of mercury required may be conducted in an apparatus of the char acterillustrated, we will assume that the catalyst 20 within the system, since the rate of circulation preferably is relatively high so that the total employed comprises preformed granules-or rela mercury required within the system 4may be, for tively small pellets 'of substantially uniform size example, only ’fio to- lí[email protected] or less of the iigure and shape consisting essentially of alumina, silica above given (i. e., approximately 2 to 20 pounds l. and zirconia in the proportion of approximately 100 mols of ,SiOz to 2 mols of A120: to 5 mols of~ 25 per 100 pounds of oil cracked per hour). ,ZrOa We will also assume that the oil to be I claim as my invention: cracked is `substantially completely vaporized and heatedto a temperature of approximately 950° .F. -prior to its contact with the active cracking catalyst and that, in addition to theheat thus supplied to the oil, an additional ¿250 B. t..u.’s per pound is required to effect the desired cracking reaction in contact with the catalyst. `We will ' 1. The method of , controlling the temperature of endothermic and exothermic reactions simul taneously` conducted in separate reactionv zones ¿having heat-conductive walls, comprising the steps of `contacting a heat transfer medium in the form of a flowing film- or sheet of liquid at a` temperature‘closely approaching its vaporiza further assume that approximately 2% by weight A tion point with the heat-conductive walls of said ,of the oil is converted to heavy carbonaceous ma- 35 -exothermic reaction zone to substantially vapor terial which is deposited on the catalyst and’that ize said iluid and absorb therein the latent heat of.vaporization, causing resulting evolved vapors approximately 290 B. t. u.’s per pound of oil cracked are evolved during reactivation of the' - catalyst, reactivation being accomplished by pass ing a stream of heated oxygen-containing gases to -contact the heat-conductive’ walls of the en dothermic reaction zone and substantially con 40 dense thereon to liberate the latent heat of con densation, collecting liquid thus' condensed from the vaporized heat transfer medium and return in contact with the catalyst bed upon which said carbonaceous material has been deposited during the preceding crackingphase of the operating ingthe same in regulated quantities as said iilm Thus, theheat generated in the _exo or` sheet of liquid into contact with said walls thermic step exceeds the heat required in the 4 GI of the exothermic reaction zone. , endothermic step by 40B. t. u.’s per pound of oil 2. The method defined in claim 1, wherein the N cycle. cracked. ‘ - ' >heat content of said vapors is controllably in creased prior totheir contact with said walls of In this particular instance, mercury is utilized as the convective medium for controlling the the endothermic Vreaction zone. J « temperature Yof the reactions.v It is desired to 50 3. The method deñned- in claim 1, wherein the conduct the cracking reaction at a` temperature heat content of said ‘vapors is controllably in creased‘prior to their contact with said walls of approximately 950° F. and reactivationof the of the endothermic` reaction zone by commingling catalyst is so conducted that the average tem perature in the catalyst bed during reactivationV _a regulated additional quantity of hot vapors of - is approximately 1050° F.- The mercury is sup . plied to the zone of the reactor from which it is A said heat transfer medium therewith. 4. The method defined 1n claim 1, wherein a regulated quantity of said evolved vapors are pre sprayed over the surface‘of the tubular elements in which the exothermic reaction is taking place vented from contacting and condensing on said at a temperature of approximately 980° F. and a walls of the endothermic reaction zone. superatmospheric pressure of approximately 2501` 5. The method deiinedv in claim ,1, wherein a regulated quantity of` said evolved vapors are .prevented from contacting and condensing on `pounds per square inch is employed `in the mercury vaporizing and condensing space of the reactor. At this pressure, the mercury vaporizes ata temperature of approximately 1000cl F. yThe circulating pump is operated at such a rate that approximately 227 pounds per hour of mercury are circulated through the system per 100 pounds A»of oil cracked per hour. This figure is derived by dividing the heat evolved during regenera tion, per 100 pounds of oil cracked,` by the heat o! vaporization of mercury which is approxi mately 127.5 B. t. u.’s per pound (i. e., 29,000 divided by 127.5V equals 227+). However, when we divide ,the B. t. u.’s required to crack ,100’ said walls of the endothermic reaction zone, said lregulatedquantity of vapors being separately condensed and the resultingeondensate returned with the other liquid components of said heat v.transfer medium into contact with said walls of » , , the exothermic reaction zone. 6. The method defined in claim 1, wherein the temperature of said heat transfer medium is readjustedLot the desired value prior to each successive contact. thereof with said walls of the _l exothermic reaction zone. - 7. An apparatus 'of the class described com pounds of oil by the heat of condensation of 75 prising an endothermic reaction zone and an exo - 2,283,832 `thermic reaction zone, both having heat-con ductive walls, means for contacting the walls‘of said exothermic zone with a ñowing ñlm of a heat transfer liquid at a temperature closely ap proaching its vaporization point, means for con` tacting vapors of said liquid with the walls of said endothermic zone, means for _collecting con densate condensed on the last-named walls, and means for returning regulated quantities of said condensate into contact with the walls of the exo thermlc zone. 8. The apparatus as defined in claim 7 further characterized in the provision of means for in creasing the heat content of said vapors prior to their contact with the walls of the endother mic zone. 9. An apparatus of theclass described com 5 prising an endothermic reaction zone and an exothermic reaction zone, both having heat-con ductive walls, means for contacting the walls of said exothermic zone with a ñowing ñlm of a heat transfer liquid at a temperature closely ap proaching its vaporization point, whereby vapors ' are evolved from said liquid, said endothermic and exothermic reaction zones being enclosed in a common vessel whereby vapors evolved from said 10 liquid contact with and condense on >the walls of the endothermic zone, an accumulator exterior of said vessel and means for supplying thereto condensate formed on the last-named walls, and means for returning liquid from the accumulator 15 to said vessel and into contact with the walls of the exothermic zone. CHARLESÍ L. THOMAS.