US2342124A - Treatment of hydrocarbons - Google Patents

Description

Fel 22, 1944- J. D. DANFORTH TREATMENT OF HYDROCARBONS H T F m Hw. me Q m D H P o .Al J 2 -bo om mv mm mm Hind@ n wm muni 9 wv v nUnlel l .f l Bimba: m mz mm mumm n. @N ,mm finnu da 1 mv Al A mmmr. d v VV A .mw .1 .ull-Hu i j F l mmmmu 2 lmotmm y adv mv J i* Ew mzmazou mmzm azou Nv vw v mw. t mohom mmsru Sxu (maior. n Q 555.5 ozoiom K WH |Ivl ATTQRNEY Patented Feb. 22, 1944 TREATMENT OF HYDROCARBQNS Joseph D. Danforth, Chicago, Ill., assigner to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application January 10, 1941, Serial No. 373,962

. 13 Claims.

This application is a continuation-impart of my co-pending application Serial No. 4370,323, illed December 16, 1940.

This invention relates to the, continuous and successive isomerization of parafnic hydrocar bons and alkylation of the resultant isomerized parains to produce higher molecular weight alkyl derivatives thereof. More specifically the process is concernedv with the isomerization' of normal paraftlns, mildly branched chain paraflins, or mixtures thereof followed by alkylation of the resulting isomerized parafns with olefins, these successive reactions beiner effected in the presence of a catalyst introduced by means ofa substantially inert fluid comprising essentially one or more of the reactants charged to a reaction zone containing a packing material.

Isomerization is applicable not only to individual parailinic hydrocarbons of straight chain structure but also to hydrocarbon mixtures containing these compounds in substantial percentages such as .straight-run gasolines and their fractions which contain in addition to paraffinic hydrocarbons of highly knocking characteristics 'other hydrocarbons comprising some paraffinic hydrocarbons of branched chain structure and the usual run of naphthenic and aromatic hydrocarbons.

The isomerization of normal butane and of normally liquid parailinic hydrocarbons such as normal pentane, normal hexane, etc., is frequently desirable in the manufacture of derivatives since the isomeric branched chain .com-f pounds .so formed are more reactive chemically, and in the case of gasoline or gasoline fractions, the isomerization also effects a marked increase inthe antiknock value of the gasolines'.

Alkylation of isomerized paralnic hydrocarbons as isoparafns and more-highly branched .catalyst to be present in the reaction zone and consequently it is. necessary -to recycle large amounts of the catalyst particularly when the reactions are' carried out in gaseous phase a1- though they may also be 'carried out in liquid phase or in mixed phase as near the critical conditions where both gases and liquids may be present in the reaction system. In order to substantially avoid the recycling of large amounts of an isomerizing and alkylating catalyst, the reaction chamber is filled with a. granular packing material upon which a substantial proportion of the catalyst deposits and is retained within the reaction zone. In this way a relatively high concentration of a catalyst is kept in the reaction zone without introducing an equivalent amount of catalyst with the hydrocarbons or other uids being charged to the process.` p

In one specii'lc embodiment the present invention comprises a process for converting parafiinic hydrocarbons of essentially straight chain structures into higher boiling parailinic hydrocarbons which comprises subjecting said paraflinic hydrocarbons of essentially straight chain structures to contact with a catalyst introduced by means of a fluid carrying medium to a reaction zone containing a granular packing material to produce a mixture containing a substantial proportion of more-highly branched chain parainic hydrocarbons; introducing an olefin-containing hydrocarbon fraction to said reaction zone at at least one point intermediate between the entrance and exit thereof to form a reaction product contain-` ing higher boiling paraiflnic hydrocarbons; separating said reaction product into' a relatively light fraction comprising essentially unconverted parailins and isomerized paralns, a mixturevof higher boiling parafnic hydrocarbons, and a residue; and recycling said light fraction comprising essentially unconverted yparaiiins and isomerized parailins to further reaction with the added olefin-containing hydrocarbon fraction.

According to the process of the present inventin normal paramnic hydrocarbons, mildly branchedv chain parainic hydrocarbons, and mixtures thereof may be isomerized into branched and more-highly branched chain parafdnic hydrocarbons and these hydrocarbons may be reacted concurrently and continuously with olenic hydrocarbons to produce substantial yields ofv higher boiling parainic' hydrocarbons of high antiknock value. In a'general way the present process is carried outby maintaining a high concentration of a volatilizable catalyst in a reaction zone without introducing an equivalent concentration of catalyst with the paraffinic hydrocarbons charged. An essential feature of the invention is the fact that the reaction zone is lled with a granular'packing material, which of itself may or may not have isomerizing and alkylating activity, upon which a substantial proportion Of the volatilizable isomerizing and alkylating catalyst is deposited and retained within the reaction zone.

Suitable catalysts for both the isomerizing and alkylating reactions comprise particularly aluminum chloride but other volatilizable materials may be used satisfactorily such as aluminum bromide, mixtures of boron iluoride and hydrogen fluoride, etc. 'I'he addition of a hydrogen halide as hydrogen chloride to a hydrocarbon mixture being subjected to isomerizing and alkylating reactions may improve the operation of the process and increase the time during which the catalyst remains active. The catalyst employed may be introduced to a reaction zone containing a packing material by means of one or more of the fluids being charged thereto. 'I'he valternative catalysts which may be used, although not necessarily on an equivalent basis, may also be introduced mechanically into the reaction zone. Thus a molten salt, paste,or slurry containing aluminum chloride may be introduced to a packed reaction zone by extrusion or other suitable means of charging aluminum chloride may be employed.

When the present combination isomerization and alkylation process is catalyzed by aluminum chloride, the aluminum chloride utilized as catalyst is picked up conveniently by a carrier fluid such as hydrogen, hydrogen chloride, a paralnlc hydrocarbon, or a mixture of any two or all of these substances may be contacted with aluminum chloride in a suitable catalyst-charging vessel maintained under conditions of temperature and pressure necessary to introduce into the carrier fluid the desired proportion of aluminum chloride. Aluminum chloride so used may be present in the charging vessel as a solid, a liuuid. a binary or ternary mixture with other metal halides, or as an adsorbed layer on a suitable adsorbent material. The iluid mixture containing both aluminum chloride and isomerized paraiilnic hydrocarbons is then charged to a reaction zone containing a granular-material which may or may not have been impregnated previously by aluminum chloride or by a mixture of one or more halides of the Friedel-Crafts type such as those of iron, zinc, aluminum, etc.

Thus aluminum chloride is charged continuously with the other reactants or intermittently so that as the isomerizing and alkylatinf,7 catalyst which remains upon the packing material within the reaction zone decreases in activity during use, a further quantity of fresh aluminum chloride is introduced to the reaction zone containing the granular packing material which includes porcelain, pumice, ilrebrick, quartz, activated charcoal. other activated carbons, diatomaceous earth, kaolin, raw and acid-treated clays, silica gel, alumina, magnesia. zirconia, titania, cornposites of silica with alumina and/or zirconia, metals possessing considerable surface as spongy iron, etc. Metal halides of the Friedel-Crafts type such as the chlorides of aluminum, copper, iron. zinc, etc., may also be composited with any of the supporting materials prior to introduction into the reaction zone as packing material when such compositing is chemically or physically feasible.

'I'he alternative reactor filling materials are not necessarily equivalent and the particular filling material yemployed in anyspecific isomerizing and LNI alkylating'reaction is dependent upon the hydro- When relatively large reactors are employed, itv

may also be desirable to introduce the mixture of carrying fluid and catalyst to a reactor at various points between the inlet and outlet thereof so that the catalyst is present in exactly the optimum concentration at all points throughout the bed of granular filling material within the reactor and also so that no excess of the catalyst is present at the point of its introduction with a resulting catalyst deficiency at other points throughout the entire bed or beds of reactor filling material.

It is proposed to carry out simultaneously both isomerization and alkylation of parains in successive sections of a packed reaction zone in the presence of a volatile catalyst carried into said zone by one or more of the fluid reactants. When aluminum chloride is the catalyst employed, the catalyst charging zone in which aluminum chloride is picked up by one or more of the reactants is preferably maintained at a temperature between about 150 and 350 F. under a pressure of from substantially atmosphericl to approximately 500 pounds per square inch. The resulting mixture of charging fluid and aluminum chloride is then introduced to a packed reaction zone maintained at a temperature between about 30 and 350 F. and preferably at a temperature generally between about and 300 F. Hydrogen chloride is preferably added to the paralnic hydrocarbon fraction charged generally to the extent of up to about 20% of its weight. It is also recommended to add hydrogen to the reac-l tion mixture generally in a quantity of not more than about 10 mole per cent of thehydrocarbons present.

Upon entering the packed reaction zone containing aluminum chloride and preferably alsov hydrogen and hydrogen chloride, a substantial proportion of the paraflinic hydrocarbons undergo isomerization into branched and more-highly branched chain parailinic hydrocarbons which are readily alkylated with oleiins introduced to said packed reaction zone at one or more points intermediate between the entrance and exit thereof. Thus a portion of the packed reactor serves as a paraffin-isomerizing zone while a later section of the same reactor serves predominantly as an alkylating zone in which a small amount of isomerization may also occur. The amounts of olefinic hydrocarbons added are such that the total mixture subjected to alkylation contains between about 1 andabout 20 mole per cent of oleflns based upon the alkylatable hydrocarbons present.

The hydrogen and/or hydrogen chloride used to assist in the isomerizing and alkylating treatments may also be employed for carrying aluminum chloride to the packed reaction zone 'as it is generally desirable to carry the catalyst by means of a fluid having relatively low activity therewith. Parailnic hydrocarbons charged or recycled in the process may also be employed for carrying the catalyst but when used for this purpose it is desirable that the catalyst-carrying fluid be substantially free from oleilns which tend to polymerize yin the catalyst pick-up zone and interfere with long continuous operation.

While a gas as those hereinabove indicated or an added substantially inert gas, is suitable for use as the fluid carrying the catalyst to a packed reaction zone or to a plurality of such zones, a liquid or vapors of a normally liquid material may be employed similarly. When the catalyst carrying medium is liquid, the catalyst as aluminum chloride is dissolved and/or dispersed in one or with other metal halides.

more of the liquids charged to the process and the resulting solution and/or dispersion is thereafter charged to a reaction zone containing .the packing material which will retain in said reaction zone a substantial proportionof the catalytic mingled in line I3 as hereinafter set forth with a recycled mixture containing hydrogen and hydromaterial charged thereto. In this -way it is also j possible to maintain a relatively high concentration of catalytic material in a reactor to which more catalyst is introduced continuously or intermittently with the charge to replenish the loss of catalyst which normally occurs by sublimation therefrom or by solution in the reaction mixture passing therethrough.

The alternative means which may be used for introducing an isomerizing and alkylating catalyst to a packed reaction zone by a uid carrying medium are not necessarily equivalent and the particular means employed in any specific case depends upon the properties of the hydrocarbons undergoing treatment, the nature of the catalyst,

the operating conditions employed, and other factors.

The features and advantages of the present invention will be further evident from a consid-` variations in the order of mixing the reactingv is directed from line 4 through line 6. valve 1, and I coil 8, which receives heat from heater 8. .to line I containing valve II and thence to catalyst gen chloride, a recycled fraction containing both unconverted and isomerized `paraiiinic hydrocarbons and when desired, all or a portion of the paraiiin-containing hydrocarbon fraction charged to the process.

Hydrogen and/or hydrogen chloride generali used in theprocess are introduced under suitable pressure or by a compressor, not shown, through line I5 containing valve I6 to line I3 and thence to reactor I1 containing a granular packing material. Also the mixture containing the charged parafiins, aluminum chloride, hydrogen, and hydrogen chloride being directed to reactor I1 by way of line I3 is therein commingled with a mixture of freshly charged hydrocarbons and recycled unconverted and isomerized hydrocarbons being directed through line 62 containing valve 63.

When only a portion of the freshly charged paraffin-containing fraction is directed through chamber I2 to pick up aluminum chloride catalyst, the remainder of the charged hydrocarbon fraction is passed through line 4 and valve 5 to line 58 and thence through coil 60, line 62, and valve 63 and thence through line I3 to reactor I1 containing a granular material which may consist of any one or a number of the reactor lling materials aforementioned. When desired, all of the freshly charged paramnic hydrocarbon fraction may be directed from line 4 through line 58 to reactor I1 as described, and under. these conditions gases being recycled through line 53 and valve 54 are utilized for picking up Aaluminum chloride in chamber I2.` Freshly charged paraiiinic hydrocarbons, recycledgases,

pick-up chamber I2 maintained at such a tem perature that a desired amount of the catalyst may be picked up by the fluid being passed therethrough. When aluminum chloride is'used as catalyst, this material may be present in chamber I2 as a solid, a liquid, an adsorbed layer on a carrier, or as a binary or ternary mixture Alternatively the catalyst may be picked up substantially by a mixture comprising essentially hydrogen, hydrogen chloride, and gases formed in the process which are introduced to line 6 from line 53 containing valve 58 as hereinafter set forth.

Although only one catalyst pick-up chamber is shown in the attached diagrammatic drawing,

more than one may be employed continuously or intermittently. Thus when a fluid or when fluid reactants are being directed through chamber I2 in order to .introduce catalyst to reactor I1,

anotherchamber similar to chamber I2. may be' emptied, cleaned, and refilled with a fresh chargel of catalyst such as aluminum chloride so that the duplicate chamber may be used in placeof chamber I2 when it becomes necessary to clean and recharge the same. From chamber I2 paraflinic hydrocarbons or a mixture containing the same and the picked-up aluminum chloride are directed throughline I3 and valve I4 and comor gases added by means not shown in the attached drawing, may be used singly or in any combination to carry aluminum chloride from catalyst pick-up chamber I2 through line I3 to reactor I1 containing a suitable packing material. v

The alternative means for introducing aluminum chloride to a packedreaction zone by a huid or by mechanical methods are not necessarily equivalent and the particular means chosen in any given case are dependent upon the hydrocarbons or hydrocarbon mixture being treated, the amount of catalyst employed, the conditions of operation, and other factors.

Branched chain parailins formed by isomerlz'ation in reactor I1 are therein alkylated with oleflns or with an olefin-containing hydrocarbon fraction admitted through line I8 and valve I9 to pump 20 which discharges through line 2| and valve 22 to reactor I1 at an intermediate point thereof. The olefin-containing fraction in line 2l may also be directed through branch line 23 and valve 24 to reactor I1. Although only two points of olefin addition to reactor I1 are shown in the attached drawing, the olen may be in-v troduced at a single point or atany number of points intermediate between the entrance and exit of reactor I1. The olefin-containing frac-y tor 30 is shown diagrammatically as one vessel.

two may be employed sot-as to have one in vuse while the other is being cleaned. When desired, said relatively heavyfresidue or, sludge containing partially spent aluminum chloride may be recycled to further contact with the parailins and olens undergoing is'omerizing and alkylating treatments. When desired, cooler 21 may be replaced by a suitable device for separating aluminum chloride vapors from the hydrocarbon stream. Such separation may, for example, be eilected in a tower containing an adsorptive material through which the hydrocarbons pass and upon which the aluminum chloride is deposited and retained.

A mixture of products containing a substan-f tially saturated aikylate formed from olefins and from a portion of the isoparaflln hydrocarbons present in reactor Il', the excess of unconverted and isomerized parafilns, hydrogen, and hydrogen chloride directed into separator 36 is passed therefrom through line 33 and valve 34 to fractionator 35 of conventional design in which a light fraction is substantially separated from higher boiling hydrocarbons. When it is desirabie to' operate fractionator 35 under a pressure above that employed in reactor I1 in order to assist in the separation of the products from the excess ci' the unconverted reactants and -to facilitate recycling of a light fraction and of unconverted and isomerized paramns, valve ,34 is closed and the mixture oi.' hydrocarbons, hydrogen, and hydrogen chloride is passed from line 33 through line 36 and valve 31 to pump 38 which discharges through line 33 and valve`4ll to line 33 beyond valve 34 and thence to fractionator 35. From fractionator 35 a mixture of unconverted and isomerized paraffins, hydrogen, hydrogen chloride, and relatively small amounts of normally gaseous parafllns as methane, ethane, propane, and butanes, is taken overhead through line 4I, valve 42, condenser 43, run-down line 44, and valve 45 to receiver 46 equipped with conventional gas release line 41 containing valve 48 and with liquid draw-ofi' line 49 containing valve 50. At least a portion of the normally-gaseous mixture collected in receiver 46 and containing hydrogen and hydrogen chloride as well as other light gases is directed from line 41 through recycle line 5I and valve 52 to line I 3,` already mentioned, in which fresh hydrogen andhydrogen chloride are commingledwith the other reactants as described and later conducted through line I3 to reactor I 1. Although the parafiln-containing fraction introduced through line 4 is indicated in the attached diagrammatic drawing as a suitable carrying iluid for the aluminum chloride catalyst, it may also be desirable to introduce to a portion of said fraction in line 6 by way of line 53 and valve I54 a portion of the gas mixture containing hydrogen and hydrogen chloride being recycled through line I aforementioned.

Thematerial present as liquid in receiver 46 is directed therefrom through line 55 and valve 56 to pump 51 which discharges through recycle line 58, valve 59, heating coil 60 which receives heat from heater 6I and then through line 62 containing valve 63 and thence through line I3 to reactor I1 aforementioned. A portion of the liquid being recycled through line 58 and comprising essentially unconverted parailns is directed through line 64 and valve 65 to a point near the top of fractionator 35 to assist in controlling the temperatures therein.

From fractlonator 35 a side cut comprising essentially gasoline boiling range hydrocarbons is withdrawn through line 63, valve 61, condenser 68, run-down line I8, and valve 10 to receiver 1I equipped with conventional gas release line 12 containing valve 13 and with liquid drawoff line 14 containing valve 15. A substantially saturated gasoline which is the desired product of the process is withdrawn to storage through line 'I4 and valve 'I5 while a higher boiling hydrocarbon mixture is discharged from the bot- 'tom of fractionator 35 through line 16 and valve 11 to cooling and storage or to other use.

In case the aluminum chloride catalyst is picked upentirely by recycled gases, the freshly charged parain-containing fraction is introduced from line'4 to line 53 through which a recycle stock is being directed to heating coil 66 and thence by way of line 62, valve 63, and line I3 to further reaction in reactor I1 containing the combined'isomerizing and alkylating catalyst deposited upon a granular carrier.

The following example is introduced as characteristic of the results expected from the practical operation of the process. although it is presented with no intention of thereby limiting the generally broad scope oi the invention as it is possible to vary the type of reactor packing material, the amount of catalyst, the conditions of operation, etc.

Normal butane is passed through a vessel containing aluminum chloride granules maintained at 225o F. under a pressure of 200 pounds per square inch. The resulting mixture of butane and aluminum chloride carried thereby is commingled withv approximately 2.5 mole per cent of hydrogen chloride and about 1 mole per cent of hydrogen and the commingled mixture is subjected' to contact in a subsequent reaction zone containing crushed porcelain maintained at 220 F. After a period of operation during which aluminum chloride deposits upon the reactor packing material, and while charging normal butane at an hourly rate (measured as liquid) approximately one-fourth that of the volume of the packed reactor, approximately 25% of'isobutane and 3% of pentanes are formed per pass through approximately the upper one-half of the packed reactor'. A mixture of fresh and recycled butanes approximately equal in volume to that of the initially charged normal butane mixed with about 5 mole per cent of added ethylene is introduced at approximately the mid point of the packed reactor maintained at such a temperature that after mixing with the butanes in the packed reactor the resulting reaction mixture will beat a temperature of approximately F. during its passage through the'remainder of the packed reactor in which isobutane reacts with ethylene to produce a higher boiling hydrocarbon fraction containing a substantial proportion of branched chain hexanes. The reaction product is discharged from the packed reactor to a separator in which a relatively small amount of aluminum chloride sludge is separated from a mixture of alkylation products and unconverted butanes. Unconverted butanes fractionated from the desired alkylation product are then recycled to further isomerization and alkylation treatment packed reactor as aforementioned.

The novelty and utility of the process of this invention are evident from the preceding specii-lcation and example given, although neither section is intended to unduly limit its generally broad scope. I

in the I claim as my invention:

1. A process for producing more valuable products from normal and mildly branched chain paraillns which comprises introducing the paraiiins to the inlet end of a reaction zone containing solid packing material and passing the hydrocarbons through the packing material to the outlet end of the reaction zone, simultaneously introducing to the inlet end of the reaction zone a fluid carrying medium containing an isomerizing and alkylating catalyst, maintaining the reaction zone under conditions such as to vdeposit a substantial portionof the catalyst on said packing material, isomerizing at least a portion of the parafiins in the reaction zone adjacent the inlet end thereof, thereby forming isoparaillns, thereafter commingling the parailins with olefinic hydrocarbons, the latter being introduced to the reaction zone at an intermediate point in the path of travel of the parafiins through said packing material to pass with the parafns through the remaining. portion of the reaction zone, reacting olelns with isoparaffins in said remaining portion of the reaction zone, and removing resultant reaction products from the outlet end of the reaction zone.

2. The process as defined in claim 1 further characterized in. that said fluid carrying medium comprises at least a portion of saidparaillns.

3. A process for producing more valuable products from normal and mildly branched chain parailins which comprises introducing the par- 5. 'I 'he process as defined in claim 3 furthercharacterized in that said uid carrying medium comprises hydrogen chloride.

6. The process as defined in claim 3 further I characterized in that said fiuid carrying medium aiiins to the inlet end of a' reaction zone containing solid packing material and passing the hydrocarbons through the packing material to the outlet end of the reaction zone, simultaneously introducing to the inlet endof the reaction zone a fluid carrying medium containing aluminum chloride, maintaining the reaction zone under conditions such as to deposit at least a portion of the aluminum chloride on said packing material, isomerizing at least aportion of the paraiilns in the reaction zone adjacent the inlet end thereof, thereby forming isoparafiins, thereafter commingling the paraiins with oleiinic hydrocarbons, the latter being introduced to the reaction zone at an intermediate point in the path of travel of the parafilns through said packing material to pass with the paraiilns through the remaining portion of the reaction zone, reacting oleilns with isoparailins in said remaining portion of the reaction zone, and removing resultant reaction products from the outlet end of the reaction zone.

comprises hydrogen.

7. The process as defined in claim 1 further characterized in that said paraiiins comprise normal butane.

8. The process as defined in claim 3 further characterized in that said parafdns comprise normal butane.

9. vA hydrocarbon conversion processl which comprises` commingling normal ,parailins with aluminum chloride and subjecting the parafflns to isomerization in the presence of the aluminum chloride, thereafter commingling oleilnic hydrocarbons with the parailin-aluminum chloride mixture and subjecting the commingled materials to alkylating conditions in areaction zone containing solid packing material, maintaining the reaction zone under conditions such as to deposit a substantial portion of the aluminum chloride on said packing material, and removing the resultant alkylation products from the reaction zone.

10.*The process as defined in claim 9 further characterized in that said normal parafilns com# prise normal butane.

1l. A hydrocarbon conversion process which comprises vcommingling normal paralns with aluminum bromide and subjecting the parailns to isomerization in the presence of the aluminum bromide, thereafter commingling oleilnic hydro-- carbons with the paraffin-aluminum bromide mixture and subjecting the conuningled materials to alkylating conditions in a reaction zone containing solid packing material, maintaining the reaction zone under conditions such as to deposit a substantial portion of the aluminum bromide on said packing material and removing the resultant alkylation products fromvthe reaction zone.

12;'The process as defined in claim 1 further characterized in that said iluid carrying medium is a liquidxcomprising at least a portion of said parafflns.

13. The process as defined in claim 3 further characterized in that said fluid carrying medium is a liquid comprising at least a portion of said paraillns.

JOSEPH D. DANFORTH.

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