US2334861A - Condensation process - Google Patents

Description

NOV. 23, 1943. v 0, BOWLES 2,334,861 v coNDENsATIoNPRocEss Filed Jan. '7, 1939 2 Sheets-Sheet l Cafzdefwer 16 QT Butaeutefze mlm-0 in 167 Mixer tz-uzane INVENTOR Verlzofz Oowle; BY

ATTORNEY Nov. 23, 1943. v Q BOWLES 2,334,861

CONDENSATION PROCESS Filed Jan. 7, 1959 2 sheets-sheet 2 being the primary per molecule'if itis found Patented Nov.'A 23, 1943.

` Vernon 0,-

Bowles, Los Angeles,l Calif., assigner to The Lummns Company, corporation of Delaware application Januaryl '1, 193s, sei-lame'. 249,691

New York, N. Y., a

z claims. (c1. zoos-saar) This invention relates to the treatment of hydrocarbons, and more particularly to the condensation or alkylation of olennes with iso-paraiiins in the presence of Vsulfuric acid, to effect a substantial conversion of said hydrocarbons into components of high anti-knock value, suitable for use as a motor fuel.

It is well known to the art that may be successfully liquid hydrocarbons acid. The polymers etc., a suitable fraction of which is then hydrogenated to produce the desiredcend product,

gaseous olenes polymerized to normally by the action f sulfuric Anamely iso-octanes and, other paraiiins o'f a similar boiling range, which have a high octane frating. The disadvantage of this process lies in the secondary step of hydrogenation, which involves special equipment of a high initial cost.

More recently iinesand iso-paraiilns can be alkylated, or condensed, in-the presence of sulfuric acid, to directly'yield a fraction of saturated hydrocarbons of high octane rating. v y v In normal present day refinery practice. there is a considerable yield of a gaseous fraction of hydrocarbons comprised substantially of .those compounds containing from one to-six carbon atoms per molecule La large part of which is butenes, butane, iso-butene and iso-butane. Such gaseous products, except as fuel, are substantially valueless, to 8% or more of the crude charge.

In accordance with my inventiomI propose to utilize variousconstituents found in this gaseous Afraction by condensing an unsaturated hydrocarbon with a` saturated hydrocarbon ofthe iso type. I iind that by suitable treatment, I can thereby obtain a liquid mateal which is of pari. ticular advantage as a motor fuel and which has a high octane rating. Such product commands asubstantial .premium as aviation gasoline, or for use as a blending agent octane rating.

More specically, I propose to condense butene with iso-butaneto produce iso-octane," but my limited to such par-' invention isjnot necessarily ticular compoimds'as it will also operate when similar compounds containing two to six carbon atoms per mol e aroused. such'compounds constituents ofhydrocarbon overhead' gases which are normgally gaseous 'imder atmospheric temperahires vand pressures. My invention may also'l be practiced on hydrocarbons' containing more y desirable to operate consist of dimers, trimers,`

ithas been suggested that olethan six" carbon 'atoms 'under suitable pressure although they often amount Inasmuch as the-normal gases inreneryfpractice lare a combination of hydrocarbon compounds including but not limited to butane, butenes and i'so-butane,. it is the'preferred practice of my invention to iirst absorb the butenes from a butane'dbutene fraction of such gases, and then remove the saturated hydrocarbons for fractionation into n-butane which is removed from the system, and iso-butane which is co1'- lected for subsequent condensation with the bu- ."tenes. The. butenes and iso-butane are then condensed in the presence of a suitable catalyst ,which may preferably be the absorbing medium containing the butenes, after which the alkymers are separated from the catalyst and are then fractionated to obtain the iso-octane.

The vprincipal production of hydrocarbons of high octane rating from a normally gaseous hydrocarbon fraction, commonly wasted in reneries, which matr be obtained with considerable economy and with fraction of renery gases with an 'iso-parain to produce a liquid alkymer ofhigh octane rating suitable for use as motor fuel.

Another and more specific object tionl is to separate and remove n-butane from a mixture of butanes and butenes, thereby facilitating the lsubsequent condensation'of the rermaining is-butane and butenes which are converted by such condensation into iso-octane.`

Another object oi this invention is to recover 'I Y iso-butane that may be present in a spent buwith gasoline of lower l rangement for tane-'butene fraction of renery gas after the butenes are absorbed, and to 'combine said isobutane with the' absorbed butenes so that substantially'none ofthe hydrocarbons are wasted.

Further objects and advantages of the Vinvention will appe'ar from the following description of vpreferred forms of embodiment of theinv'en-l tion taken in connection with the attached drawings, in which: f

. Figure v1 illustrates ment suitable for carrying out the process;

.Figure 2 illustrates an 'alternative flow arcarrying out the process' In accordance with conditions for the`pur- Y pose of making a greater yield of high octane hydrocarbons and a lower yield of normal fuels. s

object of my invention is thev o'f the inven- 'Y a preferred ilow arrangei and Y 1,' the butane-bui tene fraction of hydrocarbons from waste renery enters the through line I0,

, coil 6'|, operates under ysure and the overhead contains the iso-butane i present in the butane-butene fraction charged.

- removed from the system 'I'he acid oil layer from separator 20, containlayer on ating column,

under vsuiiicient pressure to be in the liquid form. In such mixer. it is preferably mixed with cold sulfuric acid to efl'ect a substantial absorption of the butenes by said acid. This sulfuric acid may be of a concentration of from 50 to 100%, or even greater, but preferably an acid of a concentration of from 95 to 100% will be used. Saidl mixer may be of any suitable type to eiiect an intimate contact between lthe acid yand the oleiines in said hydrocarbon-fraction, so that substantially -all of said oleiines are absorbed by the acid.

said mixture 1s than conducted in'nne la to separator 20, where it separates into two liquid phases, a light hydrocarbon layer on topmcontaining the unreacted constituents of, the butanebutene fraction, and an acid oil layer o n the bottom containing the absorbed olefines. Separator 20 is maintained at such a pressure that substantially all of said hydrocarbon layer flows through line 2| to fraitionator 64.

'I'he fractionator 6 ,which is. a 'typical fractionating column provided with a closed steam a super-atmospheric pres- This overhead ilows through line l66 to condenser moved through line 51, cooler 56 and line 59. A

closed steam coil 55 may be provided to assist the fractionation.

The acid used in absorbing the butenes invmix-v er I6, is also found most suitable for condensation of the butenes withthe iso-butane in mixer 24, and it is preferable to use this same acid, after which the acid layer in separator 36 may be recycled to furnish the acid for absorption in mixer |6. Make-up acid time at I3, and s nt acid may likewise be withdrawn at 39.

68 which furnishes reilux for fractionator 64.

Said reflux is returned through line remainder of the overhead consists of the recovered iso-butane.' The bottoms from said fractionator, consisting primarily of n-butane, are

in line 65. o

ing the absorbed butenes, flows through line 22 to mixer 24,-' where it is thoroughly agitated with the incoming iso-butane charge, also undersuiicient pressure to be liquefied, from line 26. This iso-butane charge will consist o f the aforesaid recovered iso-butane-from line 26, together with any-other available iso-butane introduced into4v the system. Mixer 24 may be of a type similar to mixer I6` except that it will be @cooling coil 3| for controlling the temperature in this mixer.V

69, and the charge, and a lower acid-oil layer, containing the' system at |2|, while the provided with 1 The resulting mixture is then conducted through line 36, cooler 32, and line 34, to separator 36, in which the mixture separates into two an alkymer layer on. top and an acid bottom. -The acid layer in separator 36,- whichmay contain a small amount of dissolved unreacted butenes, is conveniently recycled through line 36, cooler 40 and lineV |2 to mixer I6.

VThe alkymer layer from .separator 36, which may containsome unreacted iso-butane and butenes, is led through-line 42 to stabilizer 44 which The overheadconsisting substantially of said unreacted constituents, iiows through line 46 to. condenser 46, which ,furnishes reflux through line 56 to said stabilizer. The remainder of said overhead, depending upon the preponderance of line I4, or to by means off7 Y present in said is also a suitable type offractionating column.

coil 45 Vmay be provided. in

butane, as needed,

If it is desired to separate the iso-butane-from the n-butane before absorption of the butenes, the form of embodiment illustrated by Figure 2 may be used. The liquefied butane-butene charge enters fractionating tower III, equipped with closed steam reboiling coil ||2, through line H0. This tower serves the purpose of fractionally separating the iso-butane from the n-butane present in the charge; the resulting fractions each contain a portion of the oleflnes in the butane-butene charge. The n-butane fraction flows through' lines ||3 and 5, and cooler ||6, to mixer is suitably admixed with cooled recycled acid entering at I I6. The resulting mixture flows into separator |20 through line fl! and separates into two layers, an upper hydrocarbon layer, comprised of the n-hutane in .the butane-butene butenes. The n-butane is removed from the line |22 to mixer |33.

The iso-butane fraction from tower is taken ofl' overhead at |24 and is condensed in.

of said iso-butane fraction may now be'treated in -two diiierent' ways.

namely,'with recycled sulfuric containing absorbed butenes from separator |20. Generally, the latter method will be used; but occasionally, for purposes of controlling the amount o f iso-butane supplied' to the condensation reaction, it may be desirable to employ -the former method of. treatment.

When the ilrst ofthe iso-butane to mixer |26 to be admixed with recycled sulfuric acid from line |23, ,which absorbs the butenes acid or with acid ture f acid and hydrocarbons then enters separator. 3| through line |36, separating into an upper layer composed substantially of iso-butano and Aa lower acid layer containing the` absorbed butenes. This lower layer is removed in line'l |36 to be combined with the acid-oil layerfrom sepa-4 rator |26 before entering. mixer |33.v The upper iso-.butane layer les? the separator |3| inline |32. for use in the co densation reaction in mixer |33.- Any excess iso-butane may be bled from the system at |55.

.When the latter of the'iso-bu 33 through lines method is used, the remainder fraction flows directly to mixer |33 and |33. Additional isosystem at |81.

tane takes place in mixerl, which is equipped with a .cooling coil |34. The mixture of a1kymay be added from time to acid-oil is sent through method is used, the remainder fraction iiows through line |21- iso-butane fraction. The mix-l may' bel introduced into the.

Condensation of the butenes with the iso-buline |38. Stabilized carbons containing acid.

The acid layer in separator |42 is removed through cooler |43 and recycled in line |44 for further use in the absorption of butenes. Spent able quantities may be utilized, to convert the hydrocarbons into iso-octanel and the like.

acid may be removed at |51, and make-up acid may be added, as necessary, at |58.

The alkymers which separate out in |42, ilow in line |45 to stabilizer |46, where any unreacted constituents are removed by stripping. The overhead, consisting of said unreacted hydrocarbons, flows through line |49 to condenser |54, the condensate from which is returned as reflux at |5I. The remainder vof the overhead is recycled `for recovery of said hydrocarbons to mixer |33 in alkymers are removed at |48 for further treatment in bilizer |48 may be equipped with steam coil |41.

It may be found desirable to operate tower in such a-way as to have the majority of the buf tenes go oi! overhead in the iso-butane fraction. If such operation is amount of butenes in' the n-butane fraction is negligible, an alternative method of treatment may be used. The n-butane fraction may be removed directly from the system in lines lll and ||4, while the iso-butane fraction, containing substantially all the butenes, flows through lines |24, ISS/and |34 directly to mixer ill, where condensation of the butene with the iso-butane is effected. Acid is recycled from separator |41 through lines |44, |29, lil and |22to mixer |33.v

Recycling of the overhead from stabilizer |46 is not aifected by this procedure. f olefines that may be used in this process con sist of ethylene, propylene, 1butene,` 2-butene,

the alkymer still.` Bta'-,

found desirable, and the.

iso-butene (iso-butylene), diisobutylene, tri-isobutylene, 1pentene, 2pentene, tri-methyl-ethylene, iso-pentene, and the like, or of combinations of said oleiines one or more ofsaid olefines'. Iso-parailins which-may be used consist of' isobutane, iso-pentane, iso-hexane and the like. 1

Although improvements .have been described with a butane-butene fraction of hydrocarbons and iso-butane, these are not limited to reactions between oleiines and iso-parafiins having vthe. same number of carbon atoms; for example, this process may be used to bring 'about the conden-` sation of propylene with iso-pentane or any other iso-paraffin. or of butenes with iso-pentane or any other iso-paramn, or of ethylene with an isoother iso-parailin.

or of a fraction of hydro-- thatldonotwishtolce my invention within The process as a whole provides a method of economically and readily converting low boiling point hydrocarbons into a substantial yield of high grade gasoline with a. high octane rating. In addition, it furnishes a means to utilize isobutane, which at the present has little more value than as a low grade gaseous fuel. Recoveryiand recycling of any iso-butane present in the initial charge, and recycling of the overhead from the alkymer stabilizer, make possible practically full utilization of all the useful hydrocarbons introduced into the system, and thereby result in an increased yield of hig octane hydrocarbons. f'

'While I have described bodiment of my invention,

several forms of emit will be understood limited to them andthat other modifications may be made thereto, and that I therefore desire a broad interpretation of the scope and spirit of the desciiapitlon and the claims appended hereinafter.

1. A process for missing butenes with isobutane to form a high octane motor fuel, which comprises the steps' of fractionating' a butane-- butene fraction of hydrocarbons into iso-butane and n-butane fractions, each of which contains a part of said butenes, treating each of said fractions separately with concentrated sulfuric acid to absorb the butenes acid-butene mixtures from the unabsorbed hydrocarbons. combining .said mixtures, reacting the combined acid mixtures with iso-butane in the presence of the concentratedacid under alkylating conditions, separating the lallrymer product from the acid, and fractionatingsuch product to obtain the desired end product..

'2. A process butane to form a comprises the steps of fractionating a'butanebutene fraction of hydrocarbons into iso-butane and n-butane fractions, each of which contains a part of said butenes, treating the n-butane fraction with'concentrated sulfuric acid to absorb the butenes therein, separating the resulting acid-butene mixture from the unabsorbed hydrocarbons, adding further iso-butane to said iso v butane fraction, treating the iso-butane fraction with said acid mixture to absorb the butenes present in this fraction and-to alkylate the absorbed butenes with the iso-butane in the'presence of the concentrated acid, separating the alkymer product from the acid, and fractionating said alkymer product to obtain the desired end prodv mxrou o. nownna therein. separating the' for alkylating butenes with iso high octane motor fuel, which

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