US2260990A

US2260990A - Manufacture of motor fuels

Info

Publication number: US2260990A
Application number: US213148A
Authority: US
Inventors: Arthur R Goldsby; Theodore A Mangelsdorf
Original assignee: Texaco Inc
Current assignee: Texaco Inc
Priority date: 1938-06-11
Filing date: 1938-06-11
Publication date: 1941-10-28
Anticipated expiration: 1958-10-28

Description

Oct. 28, 1.941. A. R. GoLDsBY Ervm. '2,250,990

MANUFACTURE MOTOR FUELS 2 Sheets-Sheet l Filed June l1, 19(5 8 wwf? Oct. 28, 1941. A. R. GoLDsBY ETAL 2,260,990.

v MAN-FACTURE OF MOTOR FUELS Filed June ll, 1938 ,2 Sheets-Sheet 2 FIG.2.

MIXERS ARTHUR R. GoLosaY E THEooonE AMANceLsDoRF ININTORS BY ATTORNEY HYRocARBo Patented Oct. 28,'1941` i 'A .2,260,990l

UNITED STATES PATENT OFFICE 2.260.990 j 1 Arthur n. Golasby, Beacon,

N. Y., and Theodore A. Mangelsdorf, Port Arthur, Tex.. assigner: to' The Texas Company, New York, N. Y., a corpo.

ration of Delaware Application June l11, 1938,' Serial No. 213,148

r(cl. 19e-1o) A I 9 Claims. 'I'his invention relates" to the manufacture of oleiins, and has to do particularly with the liquid phase alkylation of low boiling isoparafllnsand olens in the presence of a liquid catalyst, such as sulfuric acidA to produce high anti-knock hydrocarbons of the gasoline boiling point range.

In the catalytic alkylation of isoparailins with oleiins,- it is desirable to maintain a relatively high ratio of isoparailins to olens in the reac- -tion mixture, whereby the yield and quality of the alkylation products are improved. In continuous operations, wherein streams of isoparaffins vand olefins are charged to a reaction zone, the ratio of isoparailin to,y olefin is. determined by the proportion of these materials charged to the unit, and in order to obtain a large proportion of isobutane it is necessary to feed in a small proportion of olefin and recycle a large amount of. isobutane. It has been found to b e advantageous to charge the olefin portion-wise or in multiple injections; for example, by using a plurality of stages in'which portions of the olens are introduced int successive stages of reaction. By regulating he amounts of olens ,in- Jected in the multiple stages, and allowing'time for substantial consumption of one portion of theolefln 'before the next portion is introduced; a

local preponderance of isoparain may be maintained without using a large overall excess.

In one method of\ operation, the stream of parailn hydrocarbon and catalyst may be passed in counterow relationship through stages of reaction, and the olefin chargeintroduced into a I' plurality Koi? the stages. It has ,been found satisfactory to use the step counterflow principle in which the hydrocarbon and catalyst are passed through alternating stages of mixing and setr lin h lefl i tr du ed b ulti le in-i t' g and t e D ns n o c y m p .40 said step are disclosed and claimed in copending jectioninto a plurality of the steps. According to another method. of operation, a concurrent flow may be used, rin which the catalyst and parain hydrocarbons pass through a series of sucshows an apparatus for practicing the invention according 'to the step counterilow principle. Fig- -motor fuel by the alkylation of paramns with practicing the' process of the invention. Figure l" tial amount of isoparalns and may be any mixture of hydrocarbons containing isoparains which may be alkylated with olens in the presence of `a catalyst. A desirable product is one containing low boilingisoparamns, preferably isobutaneor a hydrocarbon mixture containing a large proportion of isobutane.

` For example, products from the debutanization or fractionation of cracked or straight run gasoline, or the product from the stabilization of natural gasoline, containing principally butane and is'obutane,

-may be use'd. gThe hydrocarbon( charge may be "entirely .saturated or may contain a certain amount of oleflns present normally in the charge.

Additional oleilns may be introduced through the line 8, referred to'hereinafter, In the mixer l, the hydrocarbons are contacted by means of a stirring mechanism IIl with partially spent acid A l The `mixture passes from the mixer 1 through the line` I2 toa sintroduced through'the line II.

settler' I4. In this settler the acid and hydrocarbons separate, the acid settling to the bottom of the settler and may be withdrawn from the system through the valve controlled line V5. 'The hydrocarbons stratifying and lsettling in the upper portion vof the settler Il are lmixed with additional oleilnic charge introduced through the line `I 8 andthe mixture passed through the line II to the mixer I8. 'I'he features of prediluting the olefin feed with alkylate or-hydrocarbon phase separated from acid froma previous alkylation 1 reaction, prior to contacting of the olefin with the catalyst in the alkyiation reaction zone, and Iof the multi-stage serial flow process involving mixed by stirrer I9 with partially spent acid introduced through theline 20. The mixture of acid and hydrocarbon is passed through the line 22 to asettler 24, wherein the acid and hydroy.

carbon are allowed to4 separate. Theused acidcollecting in the lower portion of'the, settler is conducted through the valvefcontrolled line II, y

referred to heretofore, to -the mixer 1. The hydrocarbons collecting in the upper portion of the settler 24 are mixed with additionaloleilns from the line 25 and .the mixture passed through times the volume of olefins.

hydrocarbons.

the line 26- toa mixer 28, wherein the hydrocarbons are intimately contacted by means of stirrer '21 with partially spent acid from the line 28.

` The reaction mixture passes through the line 30 mixture passed through the line 33 to a mixerl35, equipped with a stirrer 36. In this mixer the the charging stock to the system is a mixture of hydrocarbons containing a substantial amount of products below C4 hydrocarbons, the gases in the fractionator 68 may contain a substantial`l amount of gases of Amore Permanent nature. These gases, for example the hydrocarbons lower ,thanv C: and all or any portion of the Cs hydrocarbons, may be discharged from the system with additional olefins from the line 32 and the hydrocarbons are contacted with used acid from the line 38 and the reaction mixture passed Y through the line 39 to a settler 40. The partially spent acid settling in this settler is conducted through the valve controlled line 29 to the mixer 28. The separated hydrocarbons are conducted from the upper portion of the settler 40 through the line 42 to a mixer 43 containing a stirring mechanism 44.

In the mixer 43 the hydrocarbon is contacted with fresh. acid introduced through the line 46 by the pump d8.

The amount of new acid introduced through the line 46 is usually between about one-half to flve times the volume of the olens, and preferably about three-fourths to one and one-half The mixture from 43 is passed through the line 49 to a settler 50 wherein the acid is allowed to settle out and pass through the valve controlled line 38 to the mixer 35. The hydrocarbons from the last settler 50 are passed through the line 5I to a mixer 52 containing stirrer 53. In the latter mixer the hydrocarbons are neutralized by contact with an alkaline material introduced through the valve controlled line 54 by the pump 55. The mixture passes from the mixer 52 through the line 56 to a settler 58 wherein the neutralizing agent settles out and lmay be withdrawn from the system through thevalve controlled line 59 or recycled to the mixer 52 through the lines 60 and 54 by the pump 55. The neutralized hydrocarbons from through the line 1I, the valve 16v therein being open and the valve 11\in the line 12 being closed. In such type of operation, a side stream comprising. the C4 hydrocarbons will be removed as a side stream through the line 13, the valve 18 therein being open.

The hydrocarbons collected in the receiver 'l5 are withdrawn through the line 80 in which is located pump 8l and returned to the mixer 1. A portion or all of the product recycled through the line 80 may be conducted through the bypass line 83 which communicates with the line 84 whereby these hydrocarbons may be introduced into one or more of the settlers I4, 24 and 3| by means of the valve controlled manifold lines I6, 25 and 32, referred to heretofore. The injection of the recycle stock through the lines I u I6, 25 and 32 may be desirable in starting up the the settler 58are passed through the line 62 to fractionator or still 64 equipped with a heating coil 65. In the fractionator 64 the hydrocarbons Iof higher boiling point than the desired fraction,

for examplev higher boiling than gasoline, are

drawn off as bottoms from -the lower portion of the fractionator through the valve controlled line 66. The hydrocarbons, for example of gasoline boiling point range and lower, are vapor- 4ized and removed as overhead through the vapor line 61. The overhead vapors are passed through the line 61 to fractionator 68 wherein the desired liquid fraction, such as gasoline, is condensed and thev stabilized product removed from the lower portion thereof through the valve controlled line 10. The uncondensed normally gaseous hydrocarbons arefractionated to obtain a fraction preferably comprising essentially C4 hydrocarbons, such as isobutane or isobutane and butane, for recycling to the system.

'Ihe type of operation i'n the fractionator v66 will depend on the nature of the lower boiling If substantia'ly only C4 hydrocarbons have been charged to the system, the uncondensed gases may consist essentiallyv of butane and isobutane which may be removed as a single fraction. In this case the vapors would thereafter colectcd in thc receiver 15. In case system or in other cases wherein the recycle stock contains a substantial amount of unreacted oleflns.

In some cases, particularly when there is an excess of normal butane in the overhead gases, it may be desirable to provide means for separatlng the isobutane from the normal butane. For example a stream of C4 hydrocarbons, comprising essentially normal and isobutane, may be removed fromfractionator v68 and a further sepation or fractionation made to produce a fraction rich in isobutane which is recycledto the alkylation operation. These features are not shown in the drawing.

The olefimc charging stock is introduced through the line 84 in which is located a pump 85. This `charging stock may comprise normally liquid or gaseous oleilns, such as cracked hydrocarbon distillates of liquid or gaseous character or both, cracking still gases, refinery gases orl gases from the cracking of normally gaseous parafl'ln hydrocarbons. It is preferable Ato use cracking still gases, for example C4 hydrocarbons or a mixture. of C3 and C4. hydrocarbons.

`Any portion or all of the charge from the line 84 may be introduced through any or all of the manifold lines' I6, 2K5 and 32. Any portion or all of the charging stock may also be passed through the branch line86 which communicates withthe line 8 whereby the product may be introduced into the 'mixer 1. As an example equal portions of the olenic charge may be introduced through the lines I6, 25 and 32 to the second, third and fourth stagesl of the system.' The amounts of the charging stocks introduced through the charge lines 5 and 84'are regulated whereby the overall ratio of isobutane to oleflns is at least 1:1 and preferably between about 3:1 and 5:1, although ratios considerably lower and higher have'l .been used. Y

The alkylation taking place in the system is of the type disclosed in the copending applical tion of Korpi-Goldsby, Serial No. 148,978, wherein the type of reactionv is described more fully. The conditions of the reaction are temperatures of 0 to 125 F. and 'preferably about 60 to 90 F.,

and pressures suflicient to maintain a. liquid phase, for example 25 to 150 pounds. The acid :nay be about'94 to 100% strength and preferl the coil |62.

ably about 94 to 98% strength. The time of reaction is about 40 to 90 minutes and preferably about 50 to 60 minutes.

Referring to the concurrent type of operation shown 'in Figure 2, the acid is introduced through valve controlled line by the pump |06 into a mixer |01. The hydrocarbon charge containing the isoparalns is also introduced into the chamber |01 through the valve controlled line |00 by the pump III). intimately mixed by the stirrer I I2, and the mixture passed through the line I|4 to a second mixer I|5 equipped with a stirrer I I6. 'Ihe product from the mixer I I5 passes through the line II1 to the mixer ||8 equipped with a stirrer |I9. The products from mixer ||8 are conducted through the line I2I vto a fourth mixer |22 equipped with stirrer |23. The products from the mixer |22 are passed through line |24 to the nal mixer |25 containing a stirring mechanism |26.

Thev olefinic charge is introduced through the The hydrocarbons and acid are cluding isobutane, is taken oi as a side stream through'the line |12 and condenser |13, for'ning a condensate which is collected in the receive`r\ |15. In case there are no gases of a more permarient nature, such as C3 hydrocarbons or lighter, a recycle product may be removed overhead through the valve controlled line |16. The operation of the fractionator I 66 is intended to be substantially the same as fractionator 68'of Figure 1, wherein the operation is described more fully. The recycled product is passed from re'- ceiver |15 through the line |16 and forced by the pump. |18 to the mixer |01. A portion or all of this recycle stock may be by-passed through the valve controlled line- |00 to be introduced into one or more-mixers |I5, ||0 and |22 by the line |30 and branch lines |33,v |34 and |35.

line by the pump I3I and may be introduced into the second, third and fourth mixers II5, 8 and |22, through the manifold lines |33, |34 and respectively. ,Branch line |31 is provided, whereby olenic charge may be introduced into the iirst mixer |01. The introduction of 4the paraiin and olefin hydrocarbons is in substantially the same manner and same proportions as described in connection with Figure 1. It is preferable, of course, to use a multiple injection of the olefins, preferably into the second, third and fourth mixers. It will be understood, of course, that hydrocarbons may also be introduced if desired into the 5th mixer by means not shown.

This introduction into the last stage also applies to the operation in Figure 1, although such introduction into the last stage was not described therein.

The productsv from the final mixer |25 are passed through the line |40 to settler |42, wherein the spent acid settles in thelower portion of the settler and may be withdifawn from the systern through the valve controlled line |44. The hydrocarbon layer collecting in the upperportion of the settler is passedthrough the line to a mixer |46 provided with a stirrer |48. In this mixer the' acid oil is intimately contactedv with a neutralizing agent, for example aqueous alkaline solution, such as caustic soda solution,

-introduced through valve controlled line |50 by pump |5I. The mixture of hydrocarbon andL neutralizing agent is passed from the mixer |46 through t'he line |53 to a settler |54 wherein the neutralizing agent settlesand may be withdrawn from the system through the line or recycled through the valve controlled line |56 and line |50 by the pump |5I. The neutralized hydrocarbons are passed from the upper portion of the settler |54 through the line |59` to fractionator or still |60, In the still, all the hydrocarbons except those of higher boiling point than the, desired fraction are vaporized by heat, for-example The higher boiling hydrocarbons or unvaporized bottoms are withdrawn from the lower portion of the fractionator through the valve controlled line |63. The vapors and gases are passed overhead from the fractionator |6||v through the vapor line |65 to fractionator or stabilizer |66.

In the stabilizer |66 the desired fraction, for example gasoline, is condensed and the stabilized product withdrawn from the lower portion of the fractionator through the line |68. The normally As an example of the operation of the invention; a saturated C4 hydrocarbon fraction, comprising a substantial' amount of isobutane, was mixed with cracking still gas comprising'a substantial amount of unsaturated Cs and C4 hydrocarbons, so that the ratio of isobutane to olens was about 3: 1. This mixture was passed through a five-stage step counterflow apparatus wherein the mixture was contacted at about F. for about an hour withA 98% acid in the ratio of about .9 to 1 by weight, based on the olefins. In this operation the hydrocarbons were all introduced into the rst stage of the system. A yield of 311 F. end point product of about 116%, based on the olelins, and having an octane number of about 91 was obtained.

The above experiment was repeated substantially in the same manner, except that the olens were introduced equally into the second and third stages of the system while the paraiin charging stock only was introduced into the rst stage. A yield 'of 311 F. end point product of about 153%, based on the olefins, and having an octane number of about 92 was obtained. The

' features Vof contacting used alkylation acid with substantially olefin-free low-boiling isoparafiln, such as isobutane, and passing the isoparaffin with stripped olefin product to an alkyla- `A yield of 311 F. end point product of about 113%, based on the olefns, and having an octane number of about 91 was obtained.

'When the same operation was carried out in a five-stage concurrent system, but the olefin hydrocarbons charged into the second, third and fourth stages, the yield obtained was approximately 151% of 311 F. end point product, based on the olefins, and having an octane number of about 92 was obtained. v l

While five stages of reaction have been described and shown in the drawings, it is to' be understood that any number of stagesmay be used to give the desired results. In general about 4 to 7 stages are satisfactory and preferably about 5 or 6 stages.

Although the invention has been describedjin connection with a recycle operation in which there is a substantial amount of isobutane recycled, it is contemplated that the invention may be applied to a once-through operation in which substantially all the isobutane is consumed in a. single pass through the system. In such' a modification, the amount of olei'lns injected in the multiple stages may vary from stage to stage. For example, the quantity of olefins introduced may be progressively less in the later stages as the amount of unreacted isobutane becomes smaller. butane may be consumed and recycling of isobutane eliminated.

It will be observed that the present invention produces a substantial increase in yield. The invention also has the advantage of reducing the formation of products outside the gasoline range, particularly the high boiling materials, and decreasing the acid consumption. In some cases also the recycling of isobutane may be eliminated.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated'in the appended claims.

We claim:

In this Way substantially all of the isozones, introducing olens in portions into a plurality of said zones to react with the isoparaflins .therein and regulating the proportions of olefins and isoparans whereby an excess of isoparafns over olens is maintained in each of said zones.

4. A process for the alkylation of isoparafilns with olens, which/comprises passing in countercurrent flow strong sulfuric acid and low boiling isoparafllns serially through a plurality of reaction stages and introducing the olefins in portions into a plurality of said stages while maintaining an excess of isoparailins over oleflns therein.

5. A process according .to claim 2 in which 4 to 7 stages of reaction are used and the olens are introduced into at least two of the first four stages through which the isopara'ins are passed.

6. A process according to claim 2 in which the relative sizeof the'` portions of olens is progressively decreased in .the successive stages to which the portions are introduced.

1. A process for the alkylation of soparaiiins i with olens, which comprises passing strong sulfurie acid'and low boiling isoparailins in excess of the olens serially through a plurality of reaction stages and introducing the oleiins in portions into a plurality of said stages of reaction.

2. A process for the alkylation of isoparaiiins with olens, which comprises passing strong sulfurie acid and low boiling isoparaiiins in excess of the olens serially through a plurality of reaction stages, splitting the feed of olens and simultaneously. introducing portions thereof into a plurality of said stages of reaction.4

3. A process for the alkylation of isoparaffins with olens, which comprises passing strong sul-1 furic acid and low boiling isoparaffins concurrently and serially through a plurality 0f reaction 7. A process for the alkylation of isoparamns with olens, which comprises passing in contin- Auous countercurrent flow strong sulfuric acid and isoparaflinsserially through a plurality of reaction stages, and continuously and simultaneously introducing the oleiins directly to each of several of said stages while maintaining an excess of isoparafns over olens'therein.

8. In a continuous process of alkylating iso-V "that there isan excess of isoparaflins over olens therein, and subjecting the oleflns so introduced tointimate contact with the isoparaiiins in the presence -of the catalyst whereby substantial alkylation of the isoparaiins is effected.

9. A process according to claim 8 in which the I catalyst is strong sulfuric acid.

ARTHUR R'. GoLDsBY. THEODORE A. MANGELsDoRF.