US2360553A - Conversion of hydrocarbons - Google Patents

Description

Oct. 17, 1944. 1 EGLOFF 2,360,553

CONVERSION OF HYDROCARBONS Filed Feb. 28, 1941 TRACT/UNA T03 'szzwle/lrlzve CHAMBER JET/16770)]! CHHMBEB FURNHCE v I I:

1772 ue77Za7 Patented Oct. 17, 1944 UNITED. .STATES PATENT :oFFlcE CONVERSION OF HYDBOCARBONS Gustav Egloii, Chicago, 111., assignor to Universal Oil Products Company, Chicago, 11L, a corporation of Delaware Application February 28, 1941, Serial No. 380,973

3 Claims. '(Cl.196-52) This invention relates to a process for the conversion of hydrocarbon oil into lower boiling hydrocarbons including gasoline. More speciflcally, it relates to a cracking process employing powdered catalyst in which the hydrocarbon oils may be converted in a two-stage operation into motor fuel of high antiknock quality and high lead susceptibility.

High temperature catalytic cracking, a term usually employed for catalytic cracking conducted in the temperature range of from approximately'850 to 1000 F., ordinarily produces gasoline boiling range hydrocarbons withantiknock ratings of from 76 to 80 Motor method which .are very valuable either for direct use as motor fuels or {or use as blending agents. Because of the relatively high olefin content, however, the motor fuel so produced may have only a moderate lead susceptibility and may therefore be unsuitablefor some purposes. On the other hand, low temperature catalytic cracking, a term usually employed for catalytic-cracking conducted in the range of from approximately 700 to 850 it, produces a substantially saturated gasoline of lower initial octane rating but of higher lead susceptibility than the high temperature process. However, the rate of conversion in the.

spent catalyst from a low temperature step, and

p the conversion products from the high temperature step are contacted with fresh catalyst in the lower temperature step. In'this manner, a highly saturated gasoline may be produced, and at the same time, the advantages or high temperature catalytic cracking may be retained.

In one specific embodiment the invention comprises supplying a heated hydrocarbon oil ,charge together with heated insufliciently converted hydrocarbons formed as hereinafter set forth and.

containing powdered catalyst to a primary con- ,version zone, separating the resultant nonlow temperature range is considerably less than that in the high temperature range so thatvthe reactor sizes, etc., for low temperature cracking must be considerably larger for the same through-put.

Cracking conducted in the presence ofa catalyst is accompanied by, the deposition of a carbonaceous substance upon the catalyst which,

as it accumulates, results in a decrease in the ability of the catalyst at constant temperature,

' catalyst than was obtained at the lower temperature with the fresh catalyst. I

The purpose of this invention is, therefore, to provide a combination high temperature-low temperature powdered catalyst cracking process in which the fresh charge is converted in a high vaporous conversion products containing, spent catalyst from the vaporous conversion products. recovering said non-vaporous conversion products containing spent catalyst, contacting said vaporous conversion products with fresh or fresh- 1y regenerated powdered catalyst in a secondary conversion zone, separating the resultant insufficiently converted hydrocarbons containing catalyst from the desired products including gasoline boiling range hydrocarbons, recovering saiddesired products, and returning said insufllcien'tly converted hydrocarbons containing catalyst" to said. primary conversion zone as hereinbefore set forth. r

' The accompanying drawing diagrammatically illustrates in side elevation one specific arrangementcf-apparatus'which may be employed for carrying out the process of this invention.

Referring now to the drawing, charging oil, which may compriseheavy naphtha, kerosene, gas oil, or any other petroleum distillate or mixture thereof, is introduced through line l,valve r m 3, line 4, and valve 5 into heating coil 8 wherein it is heated to a temperature of from 600 to 1200" E, preferably from 850 to 1000 E.

and at a pressure of from slightly superatmospheric to 500 pounds or more per square inch.

heat being supplied by means of furnace 'l. The

resultant heated material is conducted through with insuiilciently converted hydrocarformed as hereinafter described and conline giarnd valve 8 into line ll wherein it is com in taining catalyst. The catalyst and hydrocarbon mixture i introduced into reaction chamber I..-

or at a slightly reduced pressure and temperature relative to, that employed at the outlet of. temperature step in the presence f, partially as heating coil 8, andis preferably insulated to reduce radiation losses therefrom, although noinsulation appears in the drawing. The conversion products from chamber ",con-

taining the catalyst, are withdrawn through line H and valve l2 into separating chamber I! wherein a non-vaporous residual oil containing said catalyst is separated from the vaporo-'s conversion products and is withdrawn through line II and valve II. Separating chamber ll may be maintained at substantially the same temperature and pressure as reaction chamber II, but is preferably maintained at atemperature of from 600 to 900 F. ,and at a pressure of from substantially atmospheric to 200 pounds or more per square inch superatmospheric. The vaporous conversion products from chamber II are with-' drawn through line It and valve I1 and are thereafter commingled with fresh catalyst intro-- duced through line l8, valve l8, pump 20, line 2|, and valve 22.. The fresh catalyst introduced at this point may be heated to substantially the same temperature as that of the vaporous conversion products leaving chamber 13, although no provision for heating is shown in the accompanying drawing, and may, if desired, be admixed with a small proportion of the fresh charging stock, or with a small proportion of a naphthenic oil.

The resultant mixture of catalyst and conversion products is introduced through line 28 into reaction chamber 24 which is preferably maintained at substantially the same temperature and pressure as, or at a slightly reduced temperature and pressure relative to, that employed in chamber 13 and which may be insulated to reduce radiation losses therefrom, although no insulation appears in the drawing. The conversion products containing catalyst are withdrawn through line 25 and valve 26 and supplied to fractionator 21 wherein heavy reflux condensate conoline boiling range. hydrocarbons may be separated. The gasoline boiling range hydrocarbons are withdrawn through line 28 and valve 28 and may. be cooled, condensed, and separated from light gases by well known means, not shown. A.

portion of the gasoline boiling range hydrocarbons may be returned by well known means, not

shown, to fractionator 21 as a cooling and refluxing medium and the remaining portion is withdrawn as a product of the process. Fractionator 21 is maintained at substantially the same or at a reduced pressure compared to that employed in chamber 24.

Light reflux condensate may, if desired, be condensed and separated in fractionator 31 and withdrawn through line and valve 3|. some cases, however, it may be desirable to recycle all the insufliciently converted oils sepa j.

rated in fractionator 21. The heavy reflux con densate containing the catalyst is withdrawn from fractionator 21 through line 82 following;

which a portion thereof may be removed through valve 33. The remaining portion, or, if desired, all of the heavy reflux condensate may be supplied through line 34, valve 35, pump 88, line 31, and valve 88 into heating coil 30 wherein'it may be heated with or without substantial cracking,

' heat being supplied by furnace 40. The temperature of the material leaving heating coil 39 may range from 600 to 1200 F., preferably from 850 to 1050 R; and the pressure may range from slightly 'superatmospheric to 500 pounds or more per square inch. The products from heating coil 30 are directed through line 4| and valve 42 and are thereafter commingled with the material 75' leaving heating coil 6, and the mixture is supplied to reaction chamber III as hereinbefore set forth.

The catalyst which may be used in this process maycomprise any adsorbent mass, either natural or synthetic, which is known to promote the cracking reaction and which may be prepared in a finely divided form. The preferred catalyst comprises substantially hydrous silica composited with anhydrous alumina and/or hydrous zirconia, and may be prepared by the general procedure of separately precipitating or co-precipitating silicon, aluminum, and/or zirconium hydrous oxides from suitable compounds, and drying the resultant mixture at temperatures of from 800 to 1500 F., following which the mass is ground to a finely divided state. The spent catalyst which is removed from separating chamber l3 and contained'in the non-vaporous residuum may be separated therefrom by any suitabie means, such as flashing, filtration, etc., and may be regenerated by oxygen=containing gases at an elevated temperature, by solvent extraction, or by any other suitable method, and returned to the process for further use.

The following example is intended to be used only as an illustration of the process; consequently, the invention is not to be limited to the conditions thereof.

A Mid-Continent 33 A. P. I. gravity gas oil is heated to a temperature of 900 F., at a pressure of 100 pounds per square inch, and the heated oil is commingled with insufliciently converted hydrocarbons formed ashereinafter set forth and containing catalyst. The mixture is introduced into areaction zone maintained at a temperature and pressure sufficient to effect cracking.

suflicient residence time and are supplied to a separating chamber maintained at approximately 825 F. and pounds pressure wherein a nonvaporous residue containing spent catalyst is separated from the vaporous conversion products and withdrawn, The vap'orous conversion products are withdrawn from the separating chamber, commingled with fresh powdered. catalyst which has been heated to approximately 825 F; and the resulting mixture is introduced to a reaction chamber maintained at approximately 800 F. and 65 pounds pressure. The products are withdrawn and fractionated to separate insufficiently converted hydrocarbons containing the catalyst from gasoline and light gases. The insufficiently converted hydrocarbons containing the-catalyst are withdrawn from the ractionator, heated to a temperature of 950 F. at a pressure of pounds, and are commingled with the heated charge as hereinbefore set forth.

When this process is operated according to these conditions, one may obtain a 65% yield of 400 F. end point gasoline with a Motor method octane number of 76, which on the addition of 3 cc. tetraethyl lead per gallon of gasoline has an 88 octane number. Approximately 65% of the gasoline boils below 300 F. and has 9. Motor method octane number of '17, which on the addition of 3 cc. tetraethyl lead per gallon of gasoline increases to 90. Both the 400 end point and line oi relatively high olefin content. separating from the resulting conversion products nonvaporous residue containing the suspended catalyst and cracked vapors including said oleiinic gasoline, mixing a fresh catalyst with said cracked vapors including the oleilnic gasoline without prior intentional cooling of the cracked vapors and continuing the conversion at a cracking temperature below that of the first-mentioned conversion step to produce gasoline substantially iree oi oletlns', separating the substantially olefin-free gasoline from insufliciently cracked products containing the suspended catalyst and returning at least a portion 0! the latter to the first-mentioned conversion step as the source 01 said partially spent catalyst and toe!- ,iect further conversion of said insufllciently cracked products.

8. The process or claim 1 further characterized in that said-hydrocarbon oil and the insufilciently cracked products containing the suspended catalyst are independently heated to a conversion temperature, the heated oils combined and the mixture introduced to a reaction zone in which conversion is eiiected without the further addition of heat.

3. A process for the conversion of hydrocarbon oil which comprises subjecting the oil to catalytic cracking in the presence of a partially spent powdered cracking catalyst at a cracking temperature regulated to efiect conversion of said oil into gasoline containing a substantial amount oi oleflns, separating cracked vapors including .the oleflnic gasoline from the catalyst and residue, subjecting the cracked vapors without prior intentional cooling thereof to continued conversion in the presence of a fresh powdered cracking catalyst under deoleflnizlng conditions to produce a gasoline substantially free' of oleflns,

separating the substantially olefin-tree gasoline from heavier conversion products and catalyst, supplyin the latter to the first mentioned conversion step as said partially spent'catalyst, and supplying at least a portion of said heavier conversion products to the first mentioned conversion step for further treatment therein.

GUSTAV EGLOFF.

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