US2415272A

US2415272A - Conversion of hydrocarbons

Info

Publication number: US2415272A
Application number: US464082A
Authority: US
Inventors: Wayne L Benedict; William J Mattox
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1942-10-31
Filing date: 1942-10-31
Publication date: 1947-02-04
Anticipated expiration: 1964-02-04

Description

Feb. 4, 1947.

Aw. L.. BENEDICTv Er AL 2,415,272

CONVERSION OF HYDROCRBONS Fileocf. 31, 1942 a/vley Patented Feb. 4, 1947 CONVERSION F HYDROCARBONS Wayne L. Benedict and William J. Mattox, Chicago, Ill., assignors to Universal Oil Products Company, Chicago, Ill., a corporation of Dela- Ware 8 Claims.

matics.

The invention isV particularly applicable to a Application October 31, 1942, Serial No. 464,082

processior the production of aviation gasoline and selected mono-alkylated aromatics, such as toluene, ethylbenzene and the like. According to one embodiment of the invention, olefin-free alkylated aromatic hydrocarbons may be produced. v

In one specic embodiment, the present invention comprises subjecting oil boiling'above the range of gasoline to cracking in the presence of a cracking catalyst to produce a substantially saturated gasoline product, subjecting at least a portion of said gasoline to interaction with benzene in the presence of a catalyst to effect a transfer of alkyl groups from poly-alkylated aromatics contained in said gasoline to said benzene, recovering a substantially saturated gasfline product suitable for use in aviation fuel from VVthe rst step of the process, and recovering selected mono-alkylated aromatic hydrocarbons from the second step of the process.

In another specic embodiment, the invention comprises subjecting oil boiling above the range of gasoline to cracking in the presence of a cracking catalyst to produce a substantially saturated gasoline product, subjecting at least a portion of said gasoline to contact with a catalyst to eiTect saturation of the olenic hydrocarbons contained in said gasoline. subiecting the olefinfree gasoline fractions to interaction with benzene in the presence of a catalyst to eect a transfer of alkyl groups from the poly-alkylated aromatics contained in said gasoline to said benzene, and recovering a substantially saturated gasoline product suitable for use in aviation fuel from the first sten of the process. and recovering selected mono-alkylated aromatic hydrocarbons whichare substantially olefin-free from the last stepyof the process.

The particular conditions of operation to be employed in each step of the process Will depend primarily upon the charging stock to the rst step of the process which, in turn, will affect the materials to be supplied as charging stocks tothe subsequent steps of the process, and the operating conditions will also depend upon the particular products desired. For example, if`1'noor fuel is desired, the rst step of the process may comprise a non-catalytic cracking operation or it may comprise a catalytic operation in which the cracking is conducted under conditions to produce an olenic type of distillate. On the other hand, if a substantially saturated gasoline product is desired for use in aviation fuel, the first step of the process will comprise a catalytic step in which the cracking is conducted under conditions to produce a substantially saturated distillate. In any event, the distillate product will contain varying percentages of aromatics, olens, naphthenes, and parains. If substantially olen-free toluene, ethylbenzene, etc., is desired, the distillate from the rst step of the process is subjected to the hydrogen transfer step prior to being subjected to the alkyl transfer step of the process. When the products from the cracking step of the process have a sufciently low olefin content, the second step of the process may be omitted in cases where the nal alkylated aromatic product meets the desired specications as to olen content.

It is understood, of course, that the `various operations herein disclosed are not necessarily equivalent in `their results and that the particular choice will depend upon the considerations heretofore mentioned.

The invention will be explained in detail in connection with the accompanying diagrammatic flow drawing which illustrates several specic embodiments of the invention, although it is understood that Various modifications to the particular flow described may be made within the scope of the broad teachings of the present invention.

Referring to the drawing, the charging stock is introduced to the process through line I and is directed into cracking zone 2. As heretofore described, the cracking operation will depend upon the charging stock and upon the type of products desired, and thus cracking zone 2 may be of any suitable type of known cracking processes. Noncatalytic cracking operations are usuali-y conducted at temperatures within the range of from about 800 to about 1200 F. and under pressures of from about atmospheric to 1000 pounds or more. Catalytic operations are usually conducted at temperatures within the range of from about tions.

500 to about 1200 F. or moreimd under .pressures of from about atmospheric to 1000 pounds or more. In catalytic operations the hourly weight space velocity isusually within the range of from about .3 to about 5. The hourly weight velocity as used herein is defined as the4 weight of cil per hour per weight of catalyst in the reactor.

For non-catalytic operations the cracking zone usually comprises a heater, reaction chamber, ilash cha-mben' fractionating and condensing r. and an end 'boiling peint of between about 4to equipment. For catalytic operations the process may be either of a' fixed bed or moving bed type,

the latter being either of the iluidized type in which the hydrocarbons move at a faster rate within the reactor than does the catalyst, or of the slurry type in which a suspension of oil and scope ofthe present invention. The catalyst may be of either natural or syntheticorigin. A par- `ticularly suitable catalyst is of the silica-alumina type 'and comprises silica composited with alumina, zirconia and/or thoria, or the like, and

'these catalysts may be `prepared in any suitable manner.

The products from zone 2 are directed through line 3 into separation zone l. Separation zone I may comprise one or a plurality -of suitable flashing, fractionating, distilling, absorbing and/or thereto may be separated into the desired irac- Non-condensible gases may be removed from the upper portion of zone 4 and withdrawn from the process through line 5 or allor a portion of these products may be returned by way of lines 6 and I to theA cracking zone. This type of operation is particularly desired when the cracking is conducted in the presencefof'hydrogen' or other' gases. Higher boiling residue may be'withdrawn .from the lower portion of zone l through line 'l2 and removed from the process. When desired.-

and particularly when the cracking is conducted in the presence of catalysts, all or a portion of the Aresidue may be returned by way of lines 8, 9, I0, and I to the cracking step for further conversion therein. A lower boiling recycle oil, when Vdesired, may be separated in zone 4 and removed therefrom through line II and withdrawn from the process. Preferably, however, at least a portion' of this recycle oil is returned by way of lines,4

and about 500 F. or more.

. All or a portion of the gasoline directed through line |.2.in the manner heretofore described is subjected to treatment in zone I3 in the presence. of a suitable .catalyst and under controlled'conditions to effect saturation of the olefins con. tained therein. This zone may likewise assume any suitable-form and it may contain any suitable catalyst. A particularly effective catalyst comprises silica compositedA with alumina, zirf conia, and/or thoria, or the like, as heretofore -described in connection with the cracking step 'Y of the process. However, with these catalysts,

catalyst is passed to the heating and/or reaction the temperature employed in this step ofthe process is within the range of about 400 to about 950 F. and preferably from about 4009to about 800 F. and usually at relatively low supelratmospheric pressures. The hourly'weight space velocity is within the'broad range of .3 to5. The

:reaction which occurs in the step of the process is one of hydrogen transfer;l that. is, the oleilns are saturated by the hydrogen liberated from some of the other hydrocarbons in the reaction '.zone. However, it .is not intended to limit the in.

vention to this particular reaction since other reactions.- such as isomerization, cyclization, de' hydrogenation, etc. mayalso occur. The condi` tions in this step of the process, furthermore, are controlled so that substantially no' cracking oc? curs, and thus `a. high recovery of liquid products is obtained with 4substantially no gas formation. The products from zone I 3 aredirected through line I5 into'separation zone I6,.which zone may stripping zones whereby the products introduced comprise one or more fractionatin'g, distilling, or other suitable zones whereby the productslintroj duced thereto may be separated into the'desired fractions. Line I1 is provided for the removal of 9, I0, and I to the cracking zone for further conv version therein.

Depending upon the particular type of opera tion'selected, the gasoline fractions, which may or may not contain higher boiling material and thus have an end boiling pointof between about 400 and about 500 F. or more, may be withdrawn from zone! through line -I 2,- and in one embodif ment o f the invention, are directed into hydrogen transfer zone I 3.. When it is desired to produce aviation gasoline, the material boiling withinI or slightly above the gasoline range may first be boiling point of. between about 250 and about 350 'In case an aviation gasoline 'cut` is withdrawn any lighterproducts, although as heretofore'dek scribed, the lighter-products will in mostl cases v be of negllgiblelalnount and, whenvde'sired, line I1 `may be .omlttedg In one embodiment of lthe invention, the products maybe separated. in .zone I6 into an aviation gasoline cut having van end boiling point within the range 'of from about 250.v to about 400 F.,fand this fraction may `jbe withdrawn from the process through line; I8. This operation is particularly` suitable whenA an avi-- ation gasoline is nctwithdrawn through line I4 in the manner heretofore described, although it is within the scope ofthe invention to utilize the same even though theprior separation is made. In the latter case'it'may be desirable to blend the two streams withdrawn from lines vI4 and III 'I'he remaining productsare withdrawn' from zone I 6 through line I9., In case it is not der' sired to separate an aviation gasoline cutin zone I8. the stream withdrawn' through linei9 will contain the total products subjected to 'fr actionin zone. I3, either with or without light gases depending on whether line" I .1 is utilized.

through line I8, the stream withdrawn: through.

' line I9 will contain thehighe'rfboiling constitu *l ents. In another embodiment ofthe invention@ when desired'ythe total products from zone I3V may'be'dl'rected through 1111'es"|5, 20, 2l and IS intoalkyl transferfzone 22. As' .heretofore men 'I transfer *zone .I'Ifmay be'omitted vand the prode ucts withdrawn from zone I throughllne I2 nia be directed through unes v2| anais-to airy ferzonell.

, cient amounts to ehect a tr asesora the ch may undergo de-poly-alkylation; that is, removal 'from the benzene'ring and de-polywf tion into two or more alkyl radicals, in which case there should preferably besumcient nzene present to accept the alkyl radicals i.: ble* for transfer to-thebenzene. The benzene may be introduced to the process through line 23 and is directed through line I8 into zone 22.

Zone 22 may likewise be of any lsuitable form and may contain anysuitable catalyst whereby to effect the transfer of alkyl groups from the poly-alkylated aromatic hydrocarbons to the benzene. A particularly suitable catalyst comprises silica composited with alumina, 'zirconia and/or thoria or the like, as heretofore described. The

footed at tempera catalyst in this instance, however, is preferably or synthetic origin The reaction is usually efabout 800 to about i300 F., andv preferably within the range of from about 1000 to abcut1200"` F. Likewise, relatively low Vsuperatmospheric pres suresare employed and in most cases substantial-l es within the range of froml uw on the aromatic ring are relatively lons.

ly atmospheric pressure is'utilized. y The hourly weight space velocities are yusually less than 5. Satisfactory hourly weight space vvelocities are within the range of 0.5 to` 2. The exact conditions oioperation to be employed in this step of the process will depend upon the characteristics oi lthe material it into zone 22.

The products from zone 22 are directed through line 2t into separation zone 25. Likewise, zone it may comprise one or a plurality of flashing, iractionatins, distllling, absorbing and/or strip- -ping zones whereby the products introduced thereto may be' separated into the desired fractions. Light gases may be removed from the upper portion thereof through line 2t and may be withdrawn from the process or, when desired, these gases may be recycled to either zone 2 or zone 22 in any suitable manner not illustrated.

The toluene fraction is withdrawn from zone 2t through line 2l. lEthylbenzene may be withdrawn sure of aboutl 5 pounds per square inch and at being directed through line l irom zone 20 through line 2s. Although not ilinstr-ated in .the dra =H s other selected slated aromatics, such as isopropylbenzene, etc., may be sented from the products in zone 25 and with clrawn'thereirom in any suitable manner. When desired, a substantially aliphatic fraction may be separated from theproducts of zone 25 and withdrawn therefrom through line 29. All or a Portion oi? `this fraction is preferably recycled by way oi lines 30, it, and i to cracking zone 2 for `further conversion within the process. Higher within the scope of the present invention includes v semratlny oneor more selectedmonohslkylated aromatico such as toluene, ethylbenaene, isoprog pylbenzene, butylbenzene, etc., from the products'- in zone l and removing the same by Away of line it. In this .particular operation hydrocarbons containing six or less carbon atoms to the molie-v culle may be removed from zone-6 through line t while the selected mono-alkylated aromatic may be removed therefrom through one or more points such as line it. 'I his operation is particularly advantageous when 'asubstantially olefin-free al- Vinflated aromatic is produced in the rst step i the process. In this operation the material aromatic will be directed through line i2 either to zone l 3 or preferably to zone 22 for conversion therein. f f

4 In still another 'modiilcaticn either one or more .selected mono-alkylated aromatica may'be sepz -aratcdin zone' t and directed through line I2 to l hydrogen transfer reaction in zone Il to saturate the oleilns and to subsequently withdraw an oleiinPfree alhlated aromatic from zone I6 through line i8. In this operation the higher boiling material will be directed, by well known means not illustrated, to the alkyl transfer step of the process.

The following examples are introduced i'or the purpose ci further-illustrating the invention but not with the intention of unduly limiting the same. i i

Examplel A Gulf coast ses ou having an A. P. r. gravity. of 30.2, an initial boiling point oi' 426 F., andan This naphtha contained '18% aromatica and 3% olerlns, the rest being paramns and naphthenes.` The remaining products of the cracking operation comprised incondensible gases, recycle stock, cohaandloss. 'l

The above mentioned 300 to 400 F. naphthawas subjected to alkyl transfer reaction by being mired with two volumes oi benzene and contacted with a silica-alumina catalyst ata temperature of l022 F. under atmospheric-pressure and at a space velocity of l for a one hour process cycle. 92.5% of liquid hydrocarbons were recovered. the uncondensed gases amounting to 4% and the carbon to 3.4% by'weight. 0I the liquid hydrocarbons recovered, toluene comprised 24.9 weight per cent ci? the charge to thelsecond stop of the process. .iin ethylbenzene-xylene fractionwas recovered. which fraction comprised 28.3 weight per cent oi the naphtha charge to the second step of the process. Byrecycllng the higher boiling alkillated aromatica to Ithe alkyl transferstep, additional yields of toluene, ethylbenzene and nylene may be obtained.

Example Il' A hydrocarbon fraction boiling within4 the range of 176 F. to 392 F. and comprising 72% aromatica and 23% oleiins was subjected to treatment with a silica-alumina catalyst at a temperature of 662 F; at Aa. .space velocity of 0.5.

'No gas was formed and the hydrocarbon recovf g above the range-of the mono-alkylated ered amounted to 95.3% by weight of the charge bons boiling below 167 F., which amounted to 5 y 3% of this treated fraction, the aromatic concentrate contained no olefins. The above fraction may be mixed with two volumes of benzene and subjected to contact with a synthetically prepared silica-alumina cataly'stat a temperature 10 of about 1000 F. under atmospheric pressure and with a space velocity of 1 to yield high concentrations of oleiin-free toluene and olefin-free ethylbenzene and xylenes.

vWe claim as our invention:

1. A, combination process for the production of gasoline and alkyl aromatic hydrocarbons which comprises cracking a fresh hydrocarbon oil and an aliphatic recycle stock obtained as hereinafter described, separating from the resultant products a gasoline fraction having an end.Z point of from about 250 F. to about 350 F. and a naphtha fraction boiling above the range of said gasoline fraction and having an end point of from about 400 F. to about 500 F., said naphtha frac- 25 tion containing poly-alkylated benzene and 01e.- flns, converting olefins present in said naphtha fraction to more saturated hydrocarbons and s'eplarating a substantially olefin-free naphtha fraction, commingling benzene with said substantially olefin-free naphtha fraction and reacting said benzene -with poly-alkylated `benzene contained therein to effect "the transfer of alkyl groups to said benzene, separating'v unconverted aliphatic hydrocarbons and a substantially` olen-free mono-alkylated benzene from the products of the last named'step, recovering said mono-alkylated benzene, and recycling said. aliphatic hydrocarbons to the cracking step.

2. A combination process for the production of .40

gasoline and alkyl aromatic hydrocarbons which comprises cracking a fresh hydrocarbon oil and an aliphatic recycle stock obtained as hereinafter described,"separating from the resultant prod' ucts a fraction having an end point of from about 45.

400 F. to about 500 F., converting oleiins present in said last named fraction to more saturated hydrocarbons, separating from the resultant precincts a substantially saturated gasoline frac-l tion having an end point of from about 250 F. 50

alkylated benzene, commingling benzene with said naphtha fraction and reacting said benzene with poly-alkylated benzene contained therein to effect the transfer of alkyl groups to` said benj zene, separating unconverted aliphatic hydrocarbons and a substantially olefin-free mono-alkylated benzene from the products of the last named step, recovering said mono-alkylated benzene, and 1 recycling said aliphatic hydrocarbons to the cracking step. g

3. The process of claim 1 wherein toluene is separated from the products of the last stel-v 4. The processA of claim 1 wherein ethyl benzene is separated from the products oi' the last step.

5. Theprocess of claim 1 wherein the cracking step is effected in the presence of a silica-containing catalyst. 1

6. The process of claim 1 4wherein said reaction-of benzene with poly-alkylated benzene is effected in the presence of a silica-containing catalyst.

7. The process of claim 1 wherein said step of converting olefins present in said naphtha fraction to more saturated hydrocarbons is effected inl the presence of a silica-containing catalyst. n 8. The process of claim 2 wherein said step of converting oleiinsy to more saturated hydrocarbons is effected in the presence of a silica-con-` UNITED STATES PATENTS Number Country Date 2,242,960 Sachanen, et al. May 20, 1941 2,234,984 .Sachanen, et a1. Mar. 18, 1941 2,290,211 Shaad July 21, 1942 2,306,218 Marks Dec. 22, 1942 2,308,792 Thomas Jan. 19, 1943 2,335,596 Marschner Nov. 30, 1943' 2,343,870 Kaplan Mar. 14, 1944 2,349,834 Schmerling, et al. May/30, 1944 2,222,632 Sachanen, et a1. Nov. 26,1940 1,324,143 Brooks 4---- Dec. 9, 1919 2,010,948 Eglo Aug. 13, 1935 2,010,949 Egloii. f Aug. 13, 1935 2,367,535 i Sowa Jan. 16, 1945 2,297,773 Kanhofer 1 Oct. 6, 1942` 2,283,854 Friedman, et al. May 19, 1942 2,323,899

Day, et al. July 13,1943