US3233007A

US3233007A - Alkylation process

Info

Publication number: US3233007A
Application number: US208058A
Authority: US
Inventors: Charles C Chapman
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1962-07-06
Filing date: 1962-07-06
Publication date: 1966-02-01
Anticipated expiration: 1983-02-01

Description

F 9 c. c. CHAPMAN ALKYLATION PROCESS Filed July 6, 1962 :I.. SETTLER FRESH ISOPARAFFIN TOTAL s2 OLEFIN 7 V 22 ACID cooLER l L70 35* l ,4 32) l PROPANE INVENTOR. C. C. CHAPMAN BYW A T TORNE KS 3,233,007 ALKYLATION PROCESS Charles C. Chapman, liartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed July 6, 1962, Ser. No. 208,058 Claims. (Cl. 260--683.48)

This invention relates to an improvement in a liquid phase alkylation process involving the alkylation ofalkylatable hydrocarbon, such as an isoparafiin stream, with an alkylating agent, such as an olefin stream, utilizing a liquid catalyst, such as HF acid.

The instant invention is an improvement in the process diclosed in US. application Ser. No. 807,454, of George E. Hays and Fred T. Sherk, filed April 20, 1959, now abandoned, the subject matter thereof being claimed in continuation-in-part application Ser. No. 267,391, filed March 21, 1963. A specific aspect of the disclosed process comprises passing HF acid catalyst, isoparaffin, and olefin in admixture in liquid form upwardly thru an upright alkylation zone under alkylating conditions to form alkylate, passing the efiiuent liquid from the alkylation zone to an overhead settler to separate an upper hydrocarbon phase and a lower HF acid phase, gravitating the acid phase to a heat exchange zone communicating with the lower end of the, alkylation zone, passing the hydrocarbon phase thru a separation zone to recover a stream of alkylate and a stream of isoparaffin containing HF acid, and injecting said olefin and said stream of isoparaffin at high velocity upwardly into the lower end of said alkylation zone so as to educe HF acid from said heat exchange zone into said alkylation zone. This process completely eliminates the use of pumps for handling the HF acid, thereby eliminating one of the difliculties and problems in HF alkylation.

The recycle isoparatfin stream in the above-described process has been found to contain a substantial amount of HF acid and the mixing of the olefin with this recycle stream before injecting the admixture into the alkylation zone results in some low quality alkylate (before acid is educed into the reaction zone) due to the presence of such a low concentration of acid. This invention is concerned with an improvement in the aforesaid process whereby a higher yield of higher quality alkylate is produced.

Accordingly, it is an object of the invention to provide an improved process for alkylating an alkylatable hydrocarbon, such :as an isoparafiin, with an olefin in admixture with liquid catalyst, such as HF acid. Another object is to improve the yield of alkylate in such a process. A further object is to improve the quality of alkylate in this type of alkylation process. Other objects of the invention will become apparent to one skilled in the art upon consideration of the accompanying disclosure.

A broad aspect of the invention comprises separately injecting the total olefin feed directly into, the lower section of the alkylation zone in the alkylation process of said application so that the olefin portion of the feed is admixed with the isoparaffin portion in the presence of the total acid catalyst introduced to the reaction zone. This manner of operating increases both the yield and quality of the produced alkylate. While the process is particularly applicable to the alkylation of isobutane with olefins such as propylenes and butylenes, it is also applicable to alkylation of other talkylatable hydrocarbons. Thus, the alkylation reaction can comprise reaction of an isoparafiln with another alkylatable material such as isopropyl alcohol, tert-butyl alcohol, secondary butyl alcohol, isopropyl ether, and the like. Likewise, the corresponding alkyl esters, such as the alkyl halides, sulfates, phosphates, and fluorides of the olefins may be used as the alkylatable material with an appropriate or compatible alkylation catalyst. Other reactions to which the United States Patent 0 M 3,233,007 Patented Feb, 1, 1966 invention is applicable include alkylation of a normal paraflin with an olefin or other alkylatable material, or alkylation of an aromatic hydrocarbon with an olefin or other alkylatable material. k

The alkylation reaction is carried out with the hydrocarbon reactants in liquid phase but the reactants need not be normally liquid hydrocarbons. The reaction conditions can vary in temperature from sub-zero tempera ture to temperatures as high as several hundred degrees Fahrenheit and can be carried out at pressures varying from atmospheric to as high as 1000 p.s.i. and upward, and at space velocities in the range of 0.1 to about 20.

A variety of alkylation catalysts can be employed in the alkylation reaction including conventional catalysts such as sulfuric acid, hydrofluoric acid, phosphoric acid; metal halides including aluminum chloride, aluminum bromide, etc; and other liquid alkylation catalysts. In the alkylation of isoparafiins with olefins, a substantial molar excess of isoparafiin to olefin is employed, usually to provide a ratio of isoparaffin to olefin in the range of 5:1 to 25: 1. The hydrocarbon-to-catalyst ratio is in the range of 1:1 to 1:10 and preferably in the higher portion of the range.

A more complete understanding of the invention may be had by reference to the accompanying schematic flow diagram in which an upright reaction chamber 10 connects a horizontally elongated heat exchanger 12 with a horizontally elongated settler 14. Column 10 connects with one end section of the settler and recycle acid column 16 connects with the opposite end of the settler. Straightening veins 18 are positioned in settler 14 to assist in the phase separation of acid and hydrocarbon. The hydrocarbon phase is taken from the upper section of settler 14 thru line 20 and passed to separation equipment described hereinbelow.

Heat exchanger 12 is provided with a cooling coil 22 thru which coolant is circulated to control the temperature of the acid. Recycle isoparaifin containing an appreciable concentration of HF is injected from line 24 thru an eductor 26 upwardly into the reaction column 10 so as to educe acid in sufficient quantity from heat exchangers 12 to provide the desired acid concentration and cause mixing of the recycle stream with the acid. Eductor 26 is constructed in accordance with the eductor shown in said application Ser. No. 807,454, and comprises a flared section in line 24 terminating in a disc containing holes, each of which is provided with an injection tube extending upwardly therefrom in column 10 to provide a number of high velocity streams of recycle isoparafiin which educe the required amount of acid for the alkylation reaction.

In order to introduce the olefin portion of the feed so that it is mixed with the other alkylation reactant in an ambient of maximum acid concentration in the reaction zone, this total olefin stream is introduced thru line 28 directly into column 10 just above the upper ends of the eductor tubes. In this manner reaction between the reactants takes place under conditions of high acid concentration and excellent mixing conditions.

Fresh isoparatfin to make up for the isoparalfin converted to alkylate is, introduced preferably thru line 30 but this portion of the feed may also be alternatively introduced thru line 32,

The hydrocarbon phase in line 20 is split so that a portion passes to depropanizer 32 thru line 34 and the remaining portion passes via line 36 to deisobutanizer 38. A propane rich stream passes overhead from column 32 thru line 40 to condenser 42 in which the condensate passes thin line 44 to a settler 46 from which some HF acid is recovered thru line 48 for recycle. A portion of the propane is recycled as reflux to column 32 via line 50 under the impetus of pump 52 and another portion is passed thru line 54 to stripper 56 to strip off residual acid. Propane passes from stripper 56 to storage thru line 58.

Deisobutanizer 38 separates the isobutane from the alkylate, along with a small concentration of propane, and passes these constituents overhead to line 60 and to cooler 62 from which the cooled steam passes to surge vessel 64. A portion of the isoparaffin stream is passed by pump 66 to column 38 via line 68 for reflux and the remaining portion is passed via line '70 to line 24 for injection into the alkylation zone.

The bottoms product from column 38 is passed thru line 72 to a debutanizer (not shown) to remove n-butane from the alkylate. The alkylate is usually then fractionated for specific purposes.

All of the conditions of separation are conventional in the art and further detail in respect to the actual column conditions is unnecessary to an understanding of the invention.

While the invention has been described in connection with the drawing assuming the alkylation of isobutane with one or more olefins, other alkylation reactants may be substituted. In order to further illustrate the invention, data from two runs, Run No. 1, representing operation in accordance with the process in application Serial No. 807,454, and Run No. 2, representing operation in accordance with the invention, are presented in the table below.

1 HF cntentabout 190M100 bbl. i-Cl recycle.

2 50% propylene; 50% butylenes by volume and in Run 1, added to recycle isobutane containing HF before injecting into the reactor; in Run 2, added to admixture of recycle isobutane and HF catalyst after injecting into the reactor.

3 To maintain liquid phase.

It can be seen from the above data that injecting the total olefin feed directly into the reactor, so as to mix the same with the recycle isobutane in the presence of the total catalyst injected, efiects an improvement in both the quantity and in in the quality of the alkylate.

Certain modifications of the invention will become apparent to those skilled in the art and the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.

I claim:

1. A process for alkylating an isoparaflin with an olefin comprising the steps of:

(a) passing HF acid catalyst, isoparaffin, and olefin in admixture in liquid form upwardly thru an upright alkylation zone under alkylating conditions so as to form alkylate, the molar ratio of isoparaflin to olefin being in the range of :1 to :1;

(b) passing the efiiuent liquid from said zone to an overhead settler to separate an upper hydrocarbon phase and a lower HF acid phase;

(c) gravitating the acid phase to a heat exchange zone communicating with the lower end of said alkylation zone to control the acid temperature;

(d) passing said hydrocarbon phase thru a separation zone to recover a stream of alltylate and a stream of isoparaffin containing HF acid substantially free of said olefin;

(e) ejecting said stream of isoparafiin substantially free of olefin at high velocity upwardly into the lower end of said alkylation zone so as to educe HF acid from said heat exchange zone into said alkylation zone; and

(f) injecting the total olefin feed directly into the high velocity stream of step (e) in the lower section of said alkylation zone, separately from the recycle stream, so as to mix said olefin with said stream of isoparaffin and residual acid in the presence of total acid.

2. A process for alkylation of an alkylatable hydrocarbon with an olefin comprising the steps of:

(a) passing a liquid HF catalyst capable of effecting said alkylation, said hydrocarbon, and said olefin in admixture in liquid form upwardly thru an upright alkylation zone under alkylating conditions so as to form alkylate, said isoparafiin being in substantial molar excess over said olefin;

(h) passing the efiiuent liquid from said zone to a separation zone to separate alkylate containing unreacted hydrocarbon, and liquid HF catalyst;

(c) passing the recovered liquid HF catalyst to a heat exchange zone communicating with the lower end of said alkylation zone to control the temperature of the HE catalyst;

(d) passing the alkylate containing said unreacted hydrocarbon to a separation zone to recover separate streams of alkylate and said hydrocarbon as recycle containing an appreciable concentration of residual catalyst and substantially free of olefin;

(e) ejecting said stream of recycle hydrocarbon substantially free of olefin at high velocity upwardly into the lower end of said alkylation zone so as to educe said catalyst from said heat exchange zone into said alkylation zone; and

(f) injecting the total olefin feed directly into the high velocity stream of step (e) in the lower section of said alkylation zone, separately from the recycle stream, thereby mixing said olefin with the injected recycle stream of said hydrocarbon and residual catalyst in the presence of total HF catalyst.

3. The process of claim 1 wherein isobutane is alkylated with propylene and butylenes.

4. The process of claim 3 wherein fresh isobutane is injected in admixture with the olefins.

5. The process of claim 1 wherein fresh isoparaifin is injected in admixture with said olefin stream.

References Cited by the Examiner UNITED STATES PATENTS 2,775,636 12/1956 Rupp 260683.48 X 3,053,917 9/ 1962 Bergongnou 260683.48 X 3,080,438 3/1963 Sailors 260-683.48 3,160,673 12/1964 Black et al. 260683.58

OTHER REFERENCES Hydrofluoric Acid Alltylation, Phillips Petroleum Co., 1964, pp. 1-6.

DELBERT E. GANTZ, Primary Examiner.

ALPHONSO D. SULLIVAN, Examiner.

Claims

1. A PROCESS FOR ALKYLATING AN ISOPARAFFIN WITH AN OLEFIN COMPRISING THE STEPS OF: (A) PASSING HF ACID CATALYST, ISOPARAFFIN, AND OLEFIN IN ADMIXTURE IN LIQUID FORM UPWARDLY THRU AN UPRIGHT ALKYLATION ZONE UNDER ALKYLATING CONDITIONS SO AS TO FORM ALKYLATE, THE MOLAR RATIO OF ISOPARAFFIN TO OLEFIN BEING IN THE RANGE OF 5:1 TO 25:1; (B) PASSING THE EFFLUENT LIQUID FROM SAID ZONE TO AN OVERHEAD SETTLER TO SEPARATE AN UPPER HYDROCARBON PHASE AND A LOWER HF ACID PHASE; (C) GRAVITATING THE ACID PHASE TO A HEAT EXCHANGE ZONE COMMUNICATING WITH THE LOWER END OF SAID ALKYLATION ZONE TO CONTROL THE ACID TEMPERATURE; (D) PASSING SAID HYDROCARBON PHASE THRU A SEPARATION ZONE TO RECOVER A STREAM OF ALKYLATE AND A STREAM OF ISOPARAFFIN CONTAINING HF ACID SUBSTANTIALLY FREE OF SAID OLEFIN;