US2334159A - Treatment of hydrocarbon oils - Google Patents

Description

Nov. 9, 1943. B. s. FRIEDMAN TREATMENT 0F HYDROCARBON OILS Filed Jan. 51, 1941 llllu 'II'III FRIEDMAN INVENTOR BERNARD S'.

' cation.

Patented Nov. 9, 1943 v V =UNITED STATESk PATENT OFFICE TREATMENT oF mnocAaBoN oms Bernard S. Friedman, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application January 31, 1941, Serial No. 376,723 9 Claims. (Cl. 19e-52) This invention relates broadly to the treatment a corresponding straight-run fraction in the presof relatively heavy petroleum fractions containence of said gases, fractionating the products ing substantially no gasoline to convert them into from the aromatization treatment to produce substantial yields of gasoline of relatively high gases, gasoline and intermediate refluxes, coolanti-knock value. In a more specific sense, the ing and condensing said gasoline, and returning, invention is concerned with a combination of lnsaid gases and intermediate refluxes to further ter-related steps involving a preliminary crackcatalytic cracking. ing of a hydrocarbon fraction followed by the se- Features of the invention will be developed more lective treatment of a fraction from the rst step in detail by describing a characteristic operation under conditions designed to increase its 'antil0 in connection with the attached diagrammatic knock value to an unusual degree. Other spe- -drawing` which shows in general side elevation, cinc features emphasizing the value of the combiwithout regard to exact proportion, a system of nation will be developed in the following speciflinterconnected units in which the process may I be conducted. t

The art of converting the heavier fractions of Referring t0 the drawing. a $17001! fOr treatment petroleum into gasolinexby the use of heat, pressuch as a gas oil is introduced to the plant through ,sureand catalyst is extensive and many combinaline i containing valve 2 to a charging Pump 3 f tions of processes and apparatus have been dewhich discharges through a line 4 containing veloped which are applicable to diiIerent types of valve 5 into a heating element 6 disposed to recharging stocks. The higher anti-knock value ceive heat from furnace l. Intermediate reiiuxes of cracked gasolines compared. with straight-run Originating in the succeeding fractionating steps gasolinas is due to their high content of olens, are admitted to line 4 from line 3| as -will be,

- cyclic compounds both naphthenic and aromatic, later more speciiically described. During passage branched chain structure and aromatic hydrocarand to some extent the presence of iso-parailins through the primary heating element 6 the temwhich are known to have higher anti-knock charperature of the entering charge plus intermediacteristics than their normal counterparts. Of ates is raised'to some point from about 700 to the groups of hydrcarbOnS having high alltiabout 930 F. and the pressure is maintained/by knock value the most desirable group comprises manipulation of valves along theline of now at a obviously the iso-paraiirls Since these are en point preferamy from about 30o to about sooo tirely saturated and exhibit no tendencies toward pounds per square inch.

deterioration by polymerization ,or other con- The heated products from con 5 pass thmugh densation reaction. However, monooleiins of une 3 containing valve g to a, primary catalytic -reactor i0 which'preferably contains a ller of vcatalyst composed of materials fostering both cracking and hydrogenating reactions. For example, the cracking component may comprise Ysuch materials as alumina, zirconia, titania, thoria,A silica-alumina, or silica-alumina-zirconia bons have good anti-knock characteristics and satisfactory motor fuels are in use which contain relatively high percentages of them. The present process is an improvement in the eld of i catalytic conversion of heavy hydrocarbon fractions to produce gasoline boilinggrange distillates hi an 1 kn k l r 4 C composites, clays, either raw or acid treated, y gfIn rrlie speciiigceni'loinlxtehnpresent inveno kieSelguhr, calomed magnesite, etc., wh1lek the hytion comprises catalytically cracking interme'- drogena'ting componen-t may comprise one or more diate` boiling range petroleum fractions in the f the ondes or sumdes of Such metals as cmo" presence of hydrogen to produce substantial mmmfmqlybdenum' Zinc tungstel?! manganese yields of gasoline therefrom, fractionating the cobalt or copper' The only essentlal of the maf' products. to produce gases, gasoline fractions terial employed as a Primary catalytic reactor 1s boiling up to about 300 F., a naphtha fraction that it be able. to exert both a Cracking and hy boiling from about 300 to about .400 F., intermedrogenating action. The extent o f the' two types diate insulciently converted fractions and re- 0f reaction may be Varied by Va'lymg the'propor" siduum, cooling, condensing and collecting said tiOIlS 0f the ingredients of the catalyst` 00111D05- gasoline fraction boiling up to 300 F., returning tes employed. A convenient composite includes said intermediate' Vfractions to further catalytic a prepared alumina-'silica composite mixed with cracking, recovering said4 residuum, subjecting an alumina-molybdena composite. o

said fraction boiling from 300 to 400 F. to cata Hydrogen necessary for effecting the desired lytic aromatization treatment in the presence of degree of hydrogenation during the cracking of the charge is introduced from a source not shown through line 61 containing valve 68 to a compressor 69 which' discharges through a line 10 containing a valve 1I into the primary catalytic reactor. A gas mixture containing relatively high percentages of hydrogen which may be fractionated to increase the hydrogen content is returned from vfractionator 49 through line 65 containing valve 66. The relative proportions of hydrogen used in the primary reaction zone and the amount of make-up hydrogen introduced from line 61 will be varied to produce the best overall results of the process.

Total conversion products from primary catalytic reactor I pass through line II containing valve I 2 to a fractionating zone I3 which is represented in the drawing as a single column although it may comprise any arrangement of fractionators necessary for effecting the desired separations. From this zone gasoline vapors of relatively low boiling points, for example, approximately 100 to 300 F. are removed through line I6 containing valve I1 and condensed during passage through condenser I8, the cooled products passing through line I9 containing valve 20 to a receiver 2l having a gas release line 22 containing valve 23 and a liquid draw line 24 containing valve 25.

Intermediate reflux condensates amenable to further hydro-cracking treatment are represented as being drawn from a point near the bottom of fractionating zone I3 through line 26 containing valve 21 to a recycling pump 28 which discharges through lineY 29 containing valve 30 and .thence into line 3l containing valve 32 and leading to line 4 as already indicated. Residual material too heavy for further eicient conversion is drawn through line I4 containing valve I5.

The naphtha fraction from the primary catalytic step boiling above the previously mentioned fraction which was removed, and usually within the approximate range of 300 to 400 F. or higher, is withdrawn from fractionating zone I 3 as a sidecut through line 33 containing valve 34 and passes through a heating coil 35 disposed to receive heat from the furnace 36. In this heater the temperature of the naphtha side-cut is preferably raised to some point from about 932 to 1112" F. while the pressure is reduced to some point below 300 pounds to bring the material to some optimum pressure and temperature combination for its eective catalytic conversion in the second step of the process. Thus the heatedmroducts flow through line 31 containing valve 38 and enter a secondary catalytic reactor 4I which also receives the fixed gases from fractionating zone I3 byway of line 39 ,containing valve 40 and a regulated proportion of straight-run naphtha analogous to that withdrawn from fractionating zone I3 from line 33. This latter straight-run fraction was introducedlthrough line 42 containing -valve 43 to pump 44 which discharges through line 45 containing valve 46. The function of the secondary catalytic reactor is to aromatize the naphtha fractions introduced by contact with catalyst having essentially a dehydrogenating action. Such catalysts may comprise, for example. catalysts similar to the hydrogenating component of the mixtures used in the primary catalytic reactor-I0 and preferably such compounds as the oxides of chromium. molybdenum, vanadium, tungsten. etc., representing vgenerally numbers of theileft-hand colums of groups IV, V and VIof the periodic table. These oxides are preferably supported on relatively inert materialssuch as alumina, magnesia, clays, etc. In catalytic re- Product:

actor 4I the naphthenic constituents of the straight-run naphtha are dehydrogenated to form aromatics along with similar cyclic compounds of a partially or totally saturated character found in the cracked naphtha fraction in the rst step. 'I'here will also be a controlled amount of cyclization reactions tending to convert the aliphatic constituents of both naphtha cuts to cyclic compounds of relatively high anti-knock characteristics.

The products from catalytic reactor 4I pass through line 41 containing valve 48 to a secondary fractionating zone 49 which is preferably adapted to separate a gaseous fraction high in hydrogen, a gasoline boiling range fraction which may be blended with the 300 F. end-point cut from the primary fractionating zone and reiiuxes for returning to the primary hydro-cracking step for further treatment. Thus, as shown in the drawing the gaseous fractions from the final or secondary fractionating zone are represented as being withdrawn through line 65 containing valve 66 and returned to the primary reactor I0 while the gasoline boiling range material follows line 50 containing valve 5I, passes through condenser 52 and run-down line 53 containing valve 54 to receiver 55 which has the conventional gas release line 56 containing valve 51 and a liquid draw line 58 containing valve 59. Heavier materials suitable for further hydro-cracking treatment pass through line 60 containing valve 6I to recycle pump 62 which discharges through line 63 containing valve 64 back to line 3l and thence to the hydro-cracking zone.

The 300 F. end-point gasoline from receiver 2| constitutes a' good aviation base fuel and may be used as such. The product from receiver 55 from the second step is satisfactory for blending with motor fuels. If desired the two fractions may be combined and the blend used as motor fuel. n

The following example is given of the results as obtained in a typical run according to the process of the invention although the inventions scope is not intended to be unduly limited by the data thus presented:

A Mid-Continent gas oil was treated by passing its vapors at a temperature of 752 F. under a pressure of 700 pounds per square inch over a mixed catalyst comprising essentially a silica- 'alumina-zirconia composite impregnated with 2 percent by weight of molybdenum ltrioxide. Three mols of hydrogen per mol of gas oil vapors were mixed therewith and the rate of iiow over the catalyst was adjusted to correspond to a liquid space velocity of 1 per hour per volume of catalyst space. t

In continuous operation the following fractions were obtained in the first steps:

Once-through yield Drygas weight per cent-- 1.67 300 F. E. P. gasoline l volume per cent..v 24.5

300-400 F. naphtha do 12.7 Recycle stock do 56.4 I Carbon weight per cent-- 0.41 i.

' The'300 F. end-point gasoline Ihad an octane number of 75.5, a Reid vapor pressure of 7 pounds, a bromine number of 1, and an A. P. I.'

gravity of 66.7.

The 300 to 400 F. naphtha cut was processed l,

alumina using a temperature of 1022 F., a pressure of 50 pounds per square inch, a, liquid space velocity of 0.5, and 3 moles of hydrogen per mole of naphtha. The original naphtha cut had an A. P. I. gravity of 44.5 and an octane number of 52.5, and there Was obtained a 78.5 volume per cent yield of 84 octane number fraction which had a Reid vapor pressure of 2.6 pounds.

By ultimate recycling of insufiiciently converted materials according to the general process shown in the drawing there is produced a total yield of 73% by volume of 80 octane number gasoline having an end boiling point of 400 F.

I claim as my invention:

1. A process for the conversion of hydrocarbon oil Which comprises subjecting said oil to conversion in the presence of a catalyst having hydrogenating activity vand cracking activity, fractionating the resultant vaporous conversion products to form reilux condensate and to separate a gas fraction comprising normally gaseous Vproducts, a gasoline fraction and a naphtha fraction, subjecting said naphtha fraction to aromatization, fractionating the resulting products from the aromatization step to form reflux condensate and to separate a gas rich in free hydrogen and a gasoline fraction, and supplying the last-mentioned reflux condensate to the rst-mentioned conversion step.

2. The process of claim l further characterized in that at least a portion of the gas rich in free hydrogen is supplied to the rst-mentioned conversion step.

3. The process of claim 1 further` characterized in that at least a portion of said gas fraction is supplied to the aromatization step.

4. The process of claim 1 further characterized in that a straight-run naphtha is combined with the naphtha formed in the rst conversion step and the mixture introduced to the aromatization step.

5. A process for the conversion of hydrocarbon oil which comprises subjecting said oil to conversion in the presence of a catalyst having cracking activity and a catalyst having hydrogenating activity, fractionating the resultant vaporous conversion products to form reflux condensate and to separate a gas fraction comprising normally gaseous products, a gasoline fraction and a naphtha fraction, subjecting said naphtha fraction to aromatzation, fractionating the resulting products from the aromatization step to form reiiuxcondensate and to separate a gas rich in free hydrogen and a gasoline fraction, and supplying the last-mentioned reux condensate to the first-mentioned conversion step.

I 6. The process of claim 1 further characterized in that said hydrocarbon oi1 comprises a straightrun gas oil.

7. A process for the production of substantial yields of gasoline boiling range materials of relatively high antiknock values from a petroleum fraction substantially devoid of gasoline which comprises subjecting an intermediate boiling range petroleum fraction in the presence of hydrogen at a temperature of from about 700 F. to about 930 F. under a pressure of from about 300 to about 3000 pounds per square inch to contact with a catalyst having hydrogenating activity and a catalyst having cracking activity selected from the group consisting of composites of silica-alumina and silica-alumina-zirconia to produce substantial yields of gasoline therefrom, fractionating the products to produce gases, a

fractions and residuum, cooling, condensing andv collecting said gasoline fraction, returning said intermediate fractions to further catalytic cracking, and recovering said residuum, subjecting said naphtha fraction. to catalytic aromatization treatment at a temperature of from about 932 to about 1112 F., under a pressure ofless than 300 pounds per square inch in contact with an oxide of chromium in the presence of a corresponding straight-run fraction and in the presence of .said gases, fractionating the products from the aromatization treatment to produce gases, gasoline and intermediate reuxes, cooling and condensing said gasoline, and returning said gases and intermediate refluxes to further catalytic cracking.

8 A process for the production of substantial yields of gasoline boiling range materials of relatively high antiknock values from a petroleum fraction substantially devoid of gasoline which comprises subjecting an intermediate boiling range petroleum fraction in the presence of hydrogen at a temperature of from about 700 F. to about 930 F. under a pressure of from about 300 to -about 3000 pounds per square inch to contact with a catalyst having hydrogenating activity and a catalyst having cracking activity selected from the group consisting of composites of silica-alumina and silica-alumina-zirconia to produce substantial yields of gasoline therefrom, fractionating the products to produce gases, a gasoline fraction boiling up tolabout 300 F., a naphtha fraction boiling from about 300 F. to about 400 F. intermediate insufficiently converted fractions and residuum, cooling, condensing and collecting said lgasoline fraction, returning said intermediate fractions to further catalytic cracking, and recovering said residuum, subjecting said naphtha fraction to catalytic aromatization treatment at a temperature of from about 932 to about 1112 F., under a pressure of less than 300 pounds per square inch in contact with an oxide of vanadium in the presence of a corresponding straight-run fraction and in the presence of said gases, fractionating the products from the aromatization treatment to produce gases, gasoline and intermediate reuxes. cooling and condensing said gasoline, and returning said gases and intermediate refluxes to further catalytic cracking.

9. A process for the production of substantial yields of gasoline boiling range materials of relatively high antiknock values from a petroleum fraction substantially devoid of gasoline which comprises subjecting an intermediate boiling range petroleum fraction in the presence of hydrogen at a temperature of from about 700 F. to about 930 F. under a pressure of from about 300 to about' 3000 pounds per square inch .to

ing and collecting said gasoline fraction, returning said intermediate fractions to further cata- 4 2,334,159 lytic cracking, and recovering said residuum, subpresence of said gases. fractionating the prodjecting said naphtha fraction to catalytic aroucts from the aromatization treatment to prmatization treatment at a temperature oi' from duce gases. gasoline and intermediate refluxes, about 932 to about 1112 F., under a pressure of cooling and condensing said gasoline. and reiess than 300 pounds per square inch in contact s turning said gases and intermediate reiiuxes to with an oxide ot molybdenum in the presence of further catalytic cracking.

a corresponding straight-run fraction and in the BERNARD S. FRIEDMAN.

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