US3663646A - Alkylation with charge stock from isomerization and hydrogenation reactions - Google Patents

Abstract

AN ALKYLATION FEEDSTOCK COMPRISING BUTENE-1, BUTENE-2, ISOBUTYLENE AND N-BUTANE IS FRACTIONATED TO PRODUCE STREAM WHICH ARE ISOMERIZED TO CONVERT THE BUTENE-1 TO BUTENE-2, OR WHICH ARE HYDROGENATED TO CONVERT THE ISOBUTYLENE TO ISOBUTENE. A PLURALITY OF STREAM ARE THUS DIREACTED TO ALKYLATION TO PROVIDE INCREASED YIELD OF ALKYLATE.

Description

May 16, 1972 c. c. CHAPMAN ALKYLATION WITH CHARGE 5 TOOK FROM ISOMERIZATION AND HYDROGENATION REACTIONS Filed July 15, 1970 N 7 I BNOZ Q NOLLVNOLLDVEL-l E (/2, g m 5 v M 3 o o g :1: g 0

3NOZ wouvmouavaa N Z V 9 w .:z

Z Z Z O O 5 N N J z l- 2 mu 2% 9 ON m m g m l 5 v z z c g a N E fl o 2 I A I LL V v (D co *7 In EINOZ *7 NOliVNOliDVbL-J INVENTOR. c. c. CHAPMAN v ATTORNEYS United States Patent Oflice 3,663,646 I ALKYLATION WITH CHARGE STOCK FROM ISQMERIZATION ,AND vI' IYDR OGENATION REACTIONS ,j I Charles C. Chapman, 'Bartlesville,"0kla.',assignor to Phillips Petroleum Company Filed July 15, 1970, SenNo. 55,031

Int."Cl. C07c 3/50 U.S.'Cl. 260-6834 R -'5 Claims ABSTRACT OF THE DISCLOSURE An alkylation feedstock comprising butene-l, butene-2, isobutylene and n-butaue is fractionated to produce streams whichare isom'rized to convertthe butene-l to butene-2,'or which are hydrogenated toconvert'the isobutylene to isobutane. A plurality of streams are thus directed to alkylation to provide increased yield of alkylate.

v This invention-pertains to thealkylation of hydrocarbons.

In-one of its more specific aspects, this invention pertains to the preparation of feedstocks for alkylation.

Both hydrocarbon hydrogenation and hydroisomerization processes are well known and'hav'c been employed for some time in producing high octane blending stocks for motor fuels. There has now been developed a process in which the two processes have been 'in'tegrated'to produce optimum feedstocks for alkyl'ation. According to the method of this invention there is-pro vided a process for preparing a charge stock to an alkylation unit from a feedstream comprising butene-l, butene-Z, isobutylene, isobutane and n-buta'rie in which a separation, or fractiouatiom'is made to produce stream 1'; containing 'isobutylene, butene-l, and isobutane and stream b containing butene-2 and n-butane; stream a is hydroisomerized to convert butene-l to butene-2 as products contained in stream 6; meme is separated or fractionated to produce stream d containing'the isobutylene and ,isobutane and stream a containingbutene-Z; stream d ishydroiso'merized to produce stream 1, a stream containingisobutene, and streamsb, e and fare charged-to an alkylation unit. T

Accordingly, it' an object'of the present invention to produce optimum alkylation feedstocks The method of "this invention will be derstood if explained in conjunction withthe. attached figure which shows a simplified flow diagram of the process.

more easily un- 3,663,646 Patented May 16 1972 n-Pentane'.

About 49 metric tons per day of stream 5 is passed into the alkylation unit 2 through conduit 16, the balance of stream 5 being otherwise disposed of. Stream 6 passes into the hydroisomerization unit 3 into which 0.51 metric ton per day'Bf hydrogen are introduced through conduit 21. The product issuing from the hydroisomerization unit through conduit 8 is passed into fractionation zone 7 through conduit 10. Depending upon the availability of isobutane, as provided in the after-discussed stream 30, it may be advantageous to split stream 8 into streams 9 and 10, stream 9 being introduced directly into the alkyla- 'tion unit. While the invention is not meant to be so limited, it will be assumed herein that this procedure is followed. In this instance, compositions of these streams are as follows when employing conventional hydroisomerization catalysts and space velocities at a pressure of about 100 p.s.i.a. and a catalyst bed temperature of about 350 F.

Stream 10, passing into fractionation zone 7, is fractionated at a pressure of about 95 p.s.i.a. at a top tower The principal conversion processes involved in the j method of this invention are hydroisomerization and bydrogenation. Both of these procedures,'together with the intermediate separation, preferably fractionation, steps are well known and any of the variety of such processes may be employed to effect the process changes referred to. Hence, the details of the specific conditions under which any of these processes are carried out need not be recited.

Referring now to the attached drawing there is shown, introduced into fractionation zone 1 through conduit 4, a charge stock material. From fractionation zone 1, two streams are recovered, one through overhead conduit 6 and one through bottoms conduit 5, assuming the fractionation to be conducted at about 95 p.s.i.a., at a bottorn tower temperature of about 150 F. and a top tower temperature of about 127 F. (All streams discussed herein are designated with the same number as that conduit through which they are passed. All stream quantities are given in metric tons per day.) Stream quantities around fractionation zone 1 are as follows:

temperature of about F. and a bottom tower temperature of about 146 F., to produce a bottoms product through conduit 11 and an overhead stream through conduit 12.'Ana1ysis' of these two streams into which stream 10 is separated is as follows:

Stream 11 is introduced into the alkylation unit whereas stream 12, and 4.09 metric tons per day of hydrogen added through conduit 22, are introduced into hydrogenation unit 13. This hydrogenation unit will be operated under any of the conventional operating conditions with any of the commercially available catalysts to hydrogenate, primarily, the unsaturated butenes to butane. The

product from the hydrogenation unit is conducted through Stream N o.

Product from Overhead from hydrogena- Added fractionation Identification tion Zone 13 isobutane Zone 17 Propylene 3. 26

Propane 15. 18. 26 Isobuty n-Pentane As a result, there are introduced into alkylation zone 2, and into which is equipped with recovery facilities for the separation of the alkylate product, a plurality of streams which are directed to maximizing the yield of alkylate from the original charge stock.

The alkylation process is conventional within the art, for example, being operated at a pressure of about 100 p.s.i.a. and at a temperature of 100 F., employing hydrofluoric acid in an amount about 1 volume of acid per volume of hydrocarbon, the isobutane olefin mole ratio being about 10 to 1. Under these conditions, the propane stream, n-butane stream and alkylate product recovered through conduits 18, 19, and 20, respectively, have the analyses as shown below, in metric tons per day.

Stream N0.

Propane Butane cut from out from alkylation alkylation Alkylate Identification unit unit product Propane 23. 45 Isobutane.. 0. 22

It will be evident from the foregoing that various modifications can be made to the method of this invention. Such, however, are considered as being within the scope of the invention.

What is claimed is:

1. A method of preparing a charge stock to an alkylation from a feed-stream comprising butene-l, butene-Z, isobutylene, isobutane and n-butane which comprises (a) separating said feedstream into a first and a second stream, a principal portion of said isobutylene, butene-l and isobutane being contained in said first stream and a principal portion of said butene-Z and said n-butane being contained in said second stream;

(b) converting a principal portion of the butene-l of said first stream to butene-Z to produce a third stream containing principally isobutylene, butene-2 and isobutane;

(c) separating said third stream into a fourth and a fifth stream, a principal portion of said isobutylene and isobutane being contained in said fourth stream and a principal portion of said butene-2 being contained in said fifth stream;

(d) converting a principal portion of the isobutylene to said fourth stream to isobutane and to produce a sixth stream containing principally isobutane; and,

(e) introducing said second, fifth and sixth streams into an alkylation unit.

2. The method of claim 1 in which a portion of said third stream and a stream comprising principally isobutane are introduced into said alkylation unit.

3. The method of claim 2 in which the separating of said feedstream into a first and second stream and separating of said third stream into a fourth and fifth stream are done by fractionation.

4. The method of claim 2 in which a principal portion of the butene-l of said first stream is converted to butene- 2 by isomerization.

5. The method of claim 2 in which a principal portion of the isobutylene of said fourth stream is converted to isobutane by hydrogenation.

References Cited UNITED STATES PATENTS 2,396,853 3/1946 Jones 260-6834 R 2,450, 59 9/1948 Frey 260-68349 2,502,015 3/1950 Matuszak 260683.49 2,591,367 4/1952 McAllister 260683.49 2,594,343 4/1952 Pines 260683.49 2,820,074 1/1958 Pines 260-683.49

DELBERT E. GANTZ, Primary Examiner G. J. CRASANAKIS, Assistant Examiner U.S. Cl. X.R.

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