US2180374A - Production of liquid saturated hydrocarbons - Google Patents

Description

yNov. 21, 1939. E. E. sTAHLY Er AL PRODUCTION OF LIQUID SATURATED HYDROCARBONS Filed NOV. 19, 1938 UNIT OLE?! EZTRAcv-l .DEH VPRO 62H6 TIO/V sns:=` POL YMEPIZ A TION UNIT Patented Nov. 21, 1939v UNITED STATES PRODUCTION 0E LIQUID SATURATED HYDBOCARBONS Eldon E. Stahlyand Erwin M. Hattox, Baton Bouge, La., assig'nors to Standard 0il Development Company, a corporation o! Delaware Application November 19, 1938, Serial No. .ML350V 14 Claims.

This invention relates to improvements in the production of highly desirable components of motor fuels and pertains particularly to the production of relatively low boiling saturated aliphatic hydrocarbons which have been found to be useful in the preparation of gasolinas.

It has heretofore been proposed to produce motor fuel constituents according to a number of well known processes, such as thermal and catalytic cracking of heavier hydrocarbons. polymerization of normally gaseous olens, followed by hydrogenation, treating of crude and straight run gasoline cuts with olens to improve their octane number by alkylating the aromatic constituents thereof with normally gaseous olens, etc. It has been found possible to react paraiiinic hydrocarbons with oleins to produce saturated hydrocarbons boiling within the motor fuel range. This reaction has been denoted as alkylation. It is therefore readily apparent that a saturated branched chain normally liquid paraffin may be produced directly by alkylating a normally gaseous branched chain paraiiin, for example isobutane, by treating such a compound with a normally gaseous mono-olefin without the necessity of including a hydrogenation treatment in the process as would be the case where a polymerization process had been used.

Another advantage of the use of an alkylation process in contrast to the well known polymerization process lies in the fact that the petroleum industry is constantly seeking methods whereby it may be possible to utilize by-products of the industry and in this respect, alkylation is a dis- 35 tinct advance in the art. Large supplies of field butanes, refinery C4 cuts from crachng units, de-

butanizer units, etc., each containing substantial quantities of gaseous olens and parans, both straight and branched chain, are available. Such 40 gaseous mixtures have heretofore been fed to polymerization processes which are able to utilize only the olenic content of the mixtures.A As a consequence, the industry has found it expedient to dehydrogenate the inert paraiiinic gases coming from such units, to convert them to olens and to then refeed these gases tothe polymerization processes. Such a procedure is unnecessary in a comparable alkylation process, and the expensive dehydrogenation of parains and subsequent necessary hydrogenation of the condensation products is eliminated, yet a gasoline of substantially the same or higher octane value is' produced.

It is an object of the present invention to pro- 55 vide a process for the production of premium grade motor -fuels by thereaction of isoparamns boiling below the desired gasoline range ormixtures thereof with monomeric mono-olens boiling below the desired gasoline range, dimers, trimers, tetramers, etc. of said monomeric monoolei'ins or mixtures thereof.

It is a further object of the invention to so carry out the alkylation of the isoparaiiins that it is possible to obtain substantially twice as large y a yield of premium grade gasoline based upon the amount of olens reacted as would be obtained in the. conventional olen polymerization processes. l

To accomplish such objects, it is a feature of the present invention to carry out the reaction under optimum reaction conditions in the presence of allq'lation catalysts which have been found to be particularly e'ective in promoting the desired reactions. It is obvious that the optimum reaction conditionswill vary for each particular catalyst employed. In general, it may be said that akylation conditions predominate when the feed rates are adjusted to provide longer contact time than would be used in corresponding poymerization reactions. Better yields of saturated products are obtained, however, where the 2l oleiin concentration is somewhat lower than in the corresponding polymerization reactions.

l Likewise it was found that the more intimate the contact between the reactants, the higher the yields of alkylated products. The feed stock is preferably introduced into the reaction zone through jets, porous thimbles, turbo-mixers and the like.

It was sometimes found to be advantageous in the production of high octane saturated fractions. suitable for motor fuels to return to the reaction zone the heavier alkylated fractions and the fractions boiling intermediate the reactants and the desired motor fuel fraction removed from the system as the nal product. It is sometimesY desirable to leave the products formed intermediate the reactants and the Ca cut in the final product since the C5, Cs and C7 saturated hydrocarbons are readily volatilized and have excellent anti-y knock properties. Likewise any unreacted reactants are separated from the desired fraction and returned to the reaction zone. Increased yields of thegdesired fraction'result whether this recycle step is carried out continuously or intermittently, whether only part or all of the recycle stock is fed into the alkylation zone together with the fresh feed.

The invention is not limited to the use of rey actants from any particular source. Single parainic and oleiinic hydrocarbons may be employed. However, it is commercially more feasible to use mixtures of hydrocarbons containing the necessary parains and olefins as part of their constituents. The reacted mixture from catalytic and thermal polymerization units, including the gaseous constituents thereof, may be directly introduced as reactants into the alkylation process of the invention. Gaseous mixtures evolved from catalytic and thermal cracking units may also he advantageously employed. It ls an essential requirement in the practice of the invention that the feed stock contain at least one isoparaiiin, preferably boiling below the boiling point of the desired final product fraction, and that the feed stock contain at least one monoolefln. Partially dehydrogenated field butanes, refinery Cs-Cs and C4 cuts, saturated paraillnic mixtures containing isoparailins and which have been enriched with mono-olens from extraneous Sources, etc. are suitable.` The invention contemplates the reactions of isobutane, isopentane,

etc. with ethylene, propylene, normal or isobutylenes, normal and branched chain amylenes, the dimers, trimers, tetramers, etc., codimers, cotrimers, cotetramers, etc., cross polymers,.interpo1ymers, etc. of these oleiins and the like. It is preferable, to insure high yields of alkylation products, to have between about 2 and about 12 mols of isoparaflin in the reactor per'mol of monovery effective in promoting alkylation. Other similar double salt complexes which are within the scope of the inventionare lithium chlor-aluminate, antimony bromaluminate, sodium bromaluminate, mercury bromaluminate, potassium chloraluminate, etc. These complex double salts may be prepared by mixing the alkali metall halide, alkaline earth metal halide, or other corresponding metal halide, for example sodium chloride, vwith slightly more aluminum halide,

for example, aluminum chloride, than is necessary for the catalyst of the desired mol ratio. The excess aluminum chloride is added in order to compensate for losses due to volatilization on heating. The mixture is heated in an open vessel until fusion occurs and a clear liquid results. At a temperature of G-450 F. some solid sodium chloride usually is present and the liquid portion of the mixture is therefore poured off through 'a wire gauze.

Such a catalyst may advantageously be impregnated or deposited uponoarriers either inert or activated with sulfuric, hydrochloric, and hydrofluoric acids or acidic gases such as HC1, S03,

SO2, HF, etc. Suitable aluminous and/or siliceous materials are activated alumina, silica gel. bauxite, fullers earth, bentonite, kleselguhr,

' pumice,ycelite, Sil-O-Cel, infusorial earth, Montmorillonite,.Marsil clays, Tonsil, Super Filtrol, activated Floridin, etc.`

Wherev the double salt type complex, is used as the catalyst, it has been found that they eventually lose their catalytic alkylation activity underlthe operatingconditions of the invention.

Any suitable reactivation or regenerative Process may be employed, for example, treatment of thecatalyst mass with inorganic acidic gases such as the hydrogen halides, HCl, HBr, or the free halogens, Cla and Bra, or by treatment with heat J5 feed rate may vary between about 0.5 to about 20 volumes/volume/hour but preferably it is maintained-between about 0.7 and about 6.2 volumes/volume/hour. All other things being the Isaine, and using a double salt complex as a catalyst, the higher the pressure, the more saturated the product becomes and the higher the yield based upon'the olenic content of the feed. Pressures ranging from between about 100 and about 3000 lbs/sq. in. gauge have been tried but pressures of from 1000 to 3000 lbs/sq. in.. preferably between about 1800 lbs/sq. in. gauge and about 3000 lbs./sq. in. gauge are most advantageous. Using the double salt complex as catalysts, temperatures of from about 300 to about 500 F. and total reaction times of from vabout 5 minutes to about lhour are employed, ,but it is preferred to use temperatures of about 400 F. v

-and total reaction times of about 7 minutes to about minutes. In general, the longer the contact time that is maintained the better .the yield that will be produced. Olenic concentrations of from about 5% toabout 40%A of the total hydrocarbon content of the feed stock are contemplated. Ordinarily, it is desirable to employ.

a relatively small concentration of oleflns since the problem -of heat dissipation from the exothermic reaction becomes more easily solved .thereby and also by such means ur'idesirableV polymerization reactions are inhibited.

Experimental evidence points to the theory that the mechanism of the alkylation reaction involves the intermediate formation of polymers or copolymers by the mono-olens followed by the degradation of these higher polymers and copolymers into an active or nascent state which permits their reaction with the parains present. The same mechanism appears to hold true where the reaction occurs between a preformed polymer or copolymer and' a parain. While the theory of the invention appears to be as described, it is to be distinctly understood that the invention is not vlimited to any theory of operation indicated by the direction whereas in cases where the alkylation the catalyst chamber at the bottom and remove mains unchanged.

ers. Any excess or unreacted reactants may be recycled to the catalytic reactor after first being mixed with the fresh feed just prior to its introduction into the catalyst chamber. If desired recycled reactants may be subjected to a dehydrogenation treatment prior to their mixing'with fresh feed. It is apparent that the process and' apparatus may be readily adapted to the carrying out of a continuous operation. Such a type of process and apparatus is familiar to -those working in the art and it is to be understood that conventional and/or minor variations therefrom may be made without departing from within the spirit or scope of the present invention.

For illustrative purposes and not with the intention of restricting the invention thereto, there is shown in the accompanying drawing a, diagrammatic illustration or ow sheet representing one specific process adapted to carrying out the invention. The process may be adapted to the use of liquid, gaseous, or solid catalysts as the exigencies of each particular case might require.

It is to be distinctly understood, however, that the invention in its broader aspects is not restricted to any particular type of apparatus or to any particular flow plan, rbut that the flow plan hereinafter described is only intended to aid in a further understanding of applicants invention.

Referring to the drawing, the olens and paraffins to be subjected to alkylation are introduced into the system through charging line I by means of pump 2. The olefnic-paraffinic hydrocarbon mixture may then be passed through pipes 6, 20, I3 and I5 controlled by valves 1 and I4 directly into alkylation reactor I6 which is filled with the desired catalyst and provided with suitable heating or cooling jackets r(not shown), or, vif it is desired to polymerize` a portion of the oleflnic content of the feed prior to the alkylation` reac-4 tion, valve 1 may be closed and the feed passed through line 4 controlled by valve 5 into any suitable conventional polymerization reactor. The olenic portion of the feed is converted into polymers thereof while the paraiinic portion re- The resultant mixture of oplymers and parains exits throughpipe I0 conlled by valve 9. Valve I8 is closed and the merized mixture enters the alkyation zone ough lines I0, I3 and I5 controlled by valves and I4.

The reacted mixture is discharged vfrom the al- :kylation reactor through pipes I9 and 25 contion zone 8 are flowed through pipe 6 controlled by valve I into pipes 20, II, I1 and I9, valves I2 and I8 being open and valves 5, 9, I4 and 26 being closed. The reacted mixture discharged from the alkylation zone I6 passes by means of lines I5, 21 and 29 into stabilizer 30. If it is desirable to first subject theAolenic-parainic hydrocarbon mixture to a preliminary polymerization treatment, valves 1, I2, I4 and 26 remain l so recycled-is withdrawn er is maintained at such a Y 3 closed and valves 5, 8, I8 and 28 are opened so that'the flow is through pipes 4, I0, I1 and I9 into-the alkylation reactor I6.

It is sometimes found advantageous to allow the ultimately.` complete alkylation reaction to proceed in small increments of the total final con-A version and to recycle Athe reactants continuously through the alkylation zone I6 through the circuit of pipes I5,`I9, vided with pump 31. Pump 36 is by-passed by allowing the iiow through pipe 64 and valve 65. It is contemplated to so recycle whether the reactants are Vcontacted with the alkylation catalyst downow or upflow, pump 36 being provided for the reversed direction of ow from that above indicated. For vdownflow operation pump 31 is by-passed by allowing the flow through pipe 66 and valve 61. A portion of the reacted mixture either intermittently or continuously, the rate of withdrawal being adjusted to insure adequate time for substantial completion of the alkylation Any suitable method of dispersing the reactants into reactor I6 is contemplated, such as jets,

turbo mixers, atomizers, porous thimbles, etc.

The reacted mixture enters stabilizer 30 through pipe 29. The temperature of the stabilizremoval of normally gaseous hydrocarbons from the normally liquid hydrocarbons. The gases comprising parains, and at times some olefins, leave the stabilizer by means of pipe 52 controlled by valve 53. If desired, these gases coming from the stabilizer may be reintroduced directly into the fresh feed pipe Iiv by closing valve 53 and opening valve so that the gases are conducted to pipe 6 by means of pipe 54, or the gases may be bled from the system through pipe 62 and valve 63, valves 53 and 55 being closed. A compressor unit (not shown) is inserted in line 54 to liquefy the gases prior to their introduction into feed line 6. It is preferable, however, to close valve 55 and open valve 53 so that these gases which are predominantly paraflinic in character are passed to a vdehydrogenation step 56 of any suitable conventional design, wherein the gaseous parafris are converted into gaseous olens either in whole or in part, the gases are liquefied, hydrogen, methane,

' 33, 39 and 35 and opening valve 34thereby effecting further conversion before final treatment, or conducted by means of pipe 42, closing valves 33 and 34 and opening valve 39, to an olefin extraction unit 43 wherein by any suitable conventional treatment, such as treatment with a solvent, for example, sulphur dioxide, any normally liquid olefinic polymers that might be present are removed. Free olens from this unit may be removed to'storage (not shown) through line 60 or they may be directly returned by means of pipes 44, 38 and 20 to the alkylation unit I6. It is to be understood that when the bottoms from stabilizer 30 are conducted back to the alkylation unit I6, only a -portion of these bottoms are so recycled at any one time, the remainder Cz and C3 fractions are removed, and the remaining gases leaving the depoint as to insure the A CII of the alternative methodsabove suggested.

The lliquid parafnic fraction. is-conveyedV to` gasoline still 48 by means of pipes-45 and 47 upon" opening valve 46. I

' trolled temperatures such that a desired gasoline fraction is removed to storage through pipe 49` required for maximum yields of saturated prod- ."uct when using a double salt complex lean in *.AlClal whereas yields practically as good can be 'obtained at 2.8 v./v./hour using a double salt complexricher in AlCls. Gasoline still 48 is maintained at suitably con-n It lis -tobeiunderstood that where mention ismade of "double salt complexes, or the equivand the heavier fractionremoved through line 50 byA opening valve 5I.

The following table is a compilation*v of datap from several experiments:

alentthe'reof, in the description and claims, it is intended toinclude the mixtures of metal halidef aluminum` halide and metall halide-iron halide compositions containing other than the requisite molecular quantities of each component for Example 1 2 a -4i. s' e` 7 s 9 1o 11 12 l 13 14 catalyst ggg .ucnNaoi on eme ice Moles AlCls/Mol NCl 1. 1 1.. 1 1. 7 1. 1 1. 2. 1. 7 1. S-2. 0 1. 1 1. 8- 2. 0 1. 8 1. 1 1. 7 2. 0 2. 0

Grams active catalyst/100 grams feed 3. 5' 13 13 2l 40 i -25 6 30 14 10 18 18. 4 19 Reaction tlme, hours 0. 15 0. 15 0. 17 0.18 0. 72 0. 1B 0. 185 0.20 0. 20A 0. 18 0. 18 0 185 0.18 0.20 Temperature, F 357 390 392 392 396 395 390-407 400 398 397 393 402 406 399 Pressure, lbs/sq. in., gauge.-- 1000 1000 1000 1750 1800 1800 1800 1800 1800 1800 i 1800 3000 3000 3000 Throughput, V./V./hou1' 3. 5 3- 5 2. 9 2- 8 0. 7 2. 8 2. 7 2. 5 2. 5 2. 8 2. 8 2. 7 2. 2. 5 Beactant feed: C

Weight percent isobutylene... 8.9 8. 9 v8. 8 8. 6 8.6 8. 3 8. 3 8. 9 8.

Weight percent n-butylene. l. 1 1. 1, l. 4 1. lv '1. 1 1. 2 l. 2 l. 0 l.

Weight percent diisobutylene.

Weight percent isobutane Weight percent ethylene Weight percent tert. butyl chloride.- Weight percent heavy reacted produc Weight percent olen reduction 89 89 y1 Cri-product:

Weight percent on isobutylene 116 145 145 170.

Example 7 represents a composite run from y four or ve separate experiments run -under substantially identical conditions and with substantially identical reactants. The products of the individual runs were combined and theproperties and composition of the products described are of'those composite products.

-cal mixtures of the components thereof.

In some of the examples, where the bromine number has been stated to be one, it has experimentally been determined as being between 0.5 and 1.

The method of preparation of the NaCl-AlCls on celite catalyst has been previously described. The mol ratio of AlCla to NaCl indicates that 1.7, Example 3, is the best ratio for alkylation, all other conditions being the same. Celite also appears to be superior to pumice as a carrier for.

the double salt complexes.

At 1800 lbs/sq. in. the 1.7 ratio gives an increase in yield anddegree of alkylation over the 1.1 ratio; a yield vof 201% (85% saturated) as compared to 170% (79% saturated). Also more Cs-Ca product was found using the higher ratio.

A temperature of around 400 F. has been found to be suitable when using the doublesalt complexes as catalysts. tained asthe pressures are increased within reasonable limits. A lower percentage of saturation isv noted at the higher pressures but more than 99% of the products boiling below 260 F. was

saturated in the higher-pressure experiments.

From the aboveexperimental data it appears that a rate of feed of about 1 v./v./hour is known compositions, although it is realized that such mixtures containing other than equimolecular amounts of each of the components may not be considered to be true double salt complexes but maybe considered, at least partially, physi- The description and claims are to be construed in such a light for want of a more convenient term to vcover the catalysts involved.

The above examples are ,intended to be but illustrative of the concept of the invention and they are notto be considered as limiting in any way the scope of the invention.

The nature and objects of the present invention having been thus fully described, what is claimed as new and useful and desired to be secured by Letters Patent is:

1. A process for the production of a composition composed predominantly of saturated liquid 1 hydrocarbons boiling in the gasoline range which Higher yields are obcomprises reacting a mixture containing at least one low boiling isoparafiin with at least one member oi' the group consisting of normally gaseous mono-olefins, dimers, trimers, tetramers and higher polymers thereof, co, inter, and crossdimers, trimers, tetramers, and higher analogous polymers thereof, in the presence of a catalyst taken from the group consisting of a catalyst of the type QXZX wherein Q stands for a metal other than aluminum, Z stands for aluminum, the -molar ratio of ZX to QX being greater than l to 1,

and X is a halogen.

2. Process as in claim 1 wherein the isoparaln 3. Process as in claim 1 wherein the alkylationl is conducted continuously and at leastv a part of any unreacted reactants are returned to the original alkylation reactions.

4. A process for the production of a composition composed predominantly 'of saturated normally liquid hydrocarbons boiling in the gasoline range which comprises reacting a mixture containing at least one low boiling isoparamn with at least one member of the group consisting of normally gaseous mono-olens, dimers, trimers, tetramers and high polymers thereof, co, inter, and cross-dimers, trimers, tetramers and higher analogous polymers thereof, in the presence of a catalyst QXZX wherein Q stands for a metal other than aluminum, Z stands for aluminum and X stands for a halogen, the ratio of ZX to QX being greater than 1 to 1, said catalyst being deposited upon a carrier.

5. Process as in claim 4 wherein the carrier is celite.

6. Process as in claim 4 wherein the alkylation is carried out a temperature between about 300 and about 500 F.

7. Process as in claim 4 wherein the alkylation is carried out at a temperature between 300 and about 500 F. undera gauge pressure of between about 1000 and about 3000 lbs./sq. in. and the catalyst is carried on celite.

8. Process as in claim 4 wherein the alkylationl is carried out at a temperature of between about 300 and about 500 F., the catalyst is supported on celite and the reactants are passed over the catlyst at a rate of from between about 0.5 and 7.0 volumes/volume/hour.

9. A process for the production of a composition composed predominantly of saturated liquid hydrocarbons boiling within the gasoline range which comprises reacting isobutane with a normally gaseous mono-olen in the presence of NaCl-A1013 double salt complex supported on celite, the mol ratio of A1013 to NaCl being between about 1.1 and about 2.0 to 1, at a temperature between about 300 and about 500 F. at

` a pressure between about 1000 and about 3000 lbs/sq. in. gauge at a throughput ofl between about 0.5 and about 7.0 volumes/volume/hour.

10. Process as in claim 9 wherein the olen is isobutylene.

11. A process for the production of a composition composed predominantly of saturated liquid hydrocarbons boilin'g within the gasoline range which comprises reacting a low boiling isoparaiiin` with a dimer of a normally gaseous mono-olen in the presence of NaCl-A1013 double salt complex supported on celite, the mol ratio of AlCla to NaCl being between about 1.1 and about 2.0 to 1, at a temperature between about `300 and about 500 F. at a pressure between about 1000 and about 3000 lbs./sq. in. gauge at a throughput of betweenabout 0.5 and about 7.0 volumes/vol ume/hour.

12. Process as in claim l1 wherein the reactants are isobutane and diisobutylene and the isobutane is present in substantial molecular excess over the diisobutylene.

13. A process for the production of normally liquid saturated hydrocarbons, which comprises reacting an iso-paraffin with a mono-olen in the presence of a catalyst of the type QXZX, wherein Q stands for a metal other than aluminum, Z stands for aluminum, the molar ratio of ZX to QX being greater than 1 to l, and X stands for and X stands for a halogen, under super-atmospleric conditions of temperature and pressure.

ELDON E. STAHLY. ERWIN M. HA'I'I'OX.

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