US2270091A - Catalytic conversion of hydrocarbons - Google Patents

Description

Jan. A13, 1942.

C. L. THOMAS EIAL CATALYTIC CONVERSION OF HYDROCARBONS Filed Aug. 21, 1959 gica/.

l Patented Jan. 13, 1942 2,270,091 CATALYTIC CONVERSION OF HYDRO- CABBONS Charles L. Thomas and Herman S. Bloch, Chicago,

lll., assignors to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application August 21, 1939, Serial No. 291,196

3 Claims. (Cl. 196-10) y I This invention relates to a process for converting hydrocarbon oils into substantially saturated motor fuels. More particularly, the process relates to the catalytic conversion of hydrocarbon oils of higher than gasoline boiling range. Although the source of hydrocarbon converted according to the present process is usually crude petroleum oil, similar oils from,

other suitable sources such as shale oil, coal tar, etc., may also be used.

The motor fuels produced according to the present invention may be used in any internal combustion engine, but they are particularly suitable for use in airplane motors because of the good antiknock properties, particularly in regard to improvement in octane number upon the addition of tetraethyl lead, and because they are substantially olefin free and meet the strict specifications applied to this type of .fuel by the 'aviation industry.

A number' of processes have been developedl to increase the yields of gasoline obtainable from petroleum oils among which is the non-catalytic cracking process, wherein oils of greater than gasoline boiling range are subjected to decomposition under suitable conditions of temperature and pressure to convert them to substantial yields of gasoline. In a similarfashion, naph- Y thas and gasolines produced by the straight-run distillation of petroleum oils may be reformed to improve their octane numbers and thus their value as motor fuel. Those reactions are carried out in various non-catalytic cracking operations.

More recently processes have been developed Y wherein hydrocarbon oils are contacted with It is with improvements in such methods of catalytically converting hydrocarbon oilsinto premium grade motor fuels that the present inventionis concerned.V l,

In one specific embodiment, the present invention comprises mixing hydrocarbon oil with an clean-containing gasoline prduced in 'a' catalytic cracking step as hereinafter described.

contacting the mixture with acracking catalyst in a primary conversion step at a temperature within the range of approximately GOO-900 F. under a pressure of substantially atmospheric to 1000 pounds per square inch. separating the gasoline and gas, passing theinsuiiiciently converted oil with or -without the addition of a portiony of the raw oil charge to a secondary catalytic cracking step wherein it is contacted. with a cracking catalyst at a temperature within the range of 800l200 F. and a pressure of substantially atmospheric to 100 pounds per square inch,-

passing the reaction products to a fractionation step, recycling a portion of the insuillciently converted oil to the secondary catalytic crack# ing step, recoveringvoleiin containing gasoline previously described, passing the gases containing olens to a polymerization step wherein the olens are subjected to the action of a catalyst under conditions of temperature and pressure adequate to convert them into substantially ous types, such as synthetic precipitated com-` posites, consisting essentially. of a-major portion of precipitated silica having added thereto relatively minorportions ofv precipitated refractory oxides to form masses consisting of silica-alumina, silica-zirconia, silica-alumina-zirconia. etc.,

said composites being substantially. free of alkali-metal compounds.`

In the following Specication, the terms s i ca-alumina, silica-zirconia, and silica-aluminazirconia masses are used in a broad sense. In-

lasmuch as the'fchemical knowledge 'of the solid state has not-been developed perfectly, it is not possible to give the structure of all solid substances. All that can be' said definitely concerning these masses is that they contain silicon, oxygen, aluminum, and/or zirconium in combination. Generally speaking, however, all these components indicate more or less low catalytic vactivity individually but in the aggregate display vhigh activlty.-'1'his activity is not an'additive function, it being relatively constant for a wide range of proportions of the components, whether in molecular or fractions of molecular proportions. No one component 'can be determined as the'one for which the remaining components may be yconsidered as the promoters according to 1000 pounds per square inch.

to conventional terminology. nor can any components be determined as the support and the others the catalyst proper.

According to the description of the preparation of the preferred catalyst given hereinafter, precipitated hydrated alumina and/or hydrated zirconia are composited with precipitated hydrated silica gel, otherwise known 'as silica hydrogel. and then the composite is washed, dried and calcined, producing a catalytic mass. However, the diierent catalysts which may be so produced therefrom do not necessarily give exactly equivalent results.

'I'he higher temperature catalytic cracking step i may be carried out within the range oi ap- The` catalytic masses employed in both conversion steps undergo an accumulation of carbonaceous deposits which must be removed from time to time, and this is suitably done by heating in the presence oi oxygen-containing gasat a temperature of 1000 F. or higher.

The catalyst employed in the polymerization step may be the so-called solid phosphoric acid catalyst `which is prepared by mixing liquid phosphoric acid with kleselguhr or lsimiliar suitable silicious material, forming into shapes, f*

and calcining. lThe catalyst isemployed at ternperatures of approximately 275-400 F. and pressures of approximately G-1000 pounds per square inch.

Another catalyst which may be used is sul'- furic acid .of greater than60% concentration.

. IThe conversion is carried out at a temperature of approximately 1Z0-250 F. and a pressure of the order of 200 pounds per square inch.

011e embodiment of the present invention is illustrated in the accompanying drawing, which is diagrammatic and should not be interpreted as .limiting the invention to the exact apparatus or conditions shown. The drawing has not been made to scale. nor has any attempt been made to proportion the equipment exactly.

Referring to the drawing, the 'raw oil charge enters through line I, valve 2, valve 3, line 4, valve 5, pump 6, valve 'I and coil 8 whlch'is disposed in heater 9. The oil is mixed with catalytic cracked gasoline from a step to be described later, which enters from line In and valve II,

all of the oil is passed through line 23, valve 24.

' line 25, valve 26, pump 21,' valve 2l to coil 2l,

joining with line 4. The hydrocarbon mixture leaves the coil at a temperature of approximately 50B-900 F. and a pressure of substantially atmosphericto 1000 lbs/sq. in., through line I2 and valve I3, entering catalytic reactor [4. The reactionproducts are removed through line I5,

interest of simplifying the drawing. Insui'll-' ciently converted oil is removed through line 20. A portion of the oil may be withdrawn from the which is disposed in heater 30. If so desired. a portion of the raw oil charge may be mixed with the insumciently converted oil by passing through line I, line; 3I, valve l2. and line 25. The oil is heated in the coil to a temperature of approximately 8001200 F. and a pressure oi' substantially atmospheric to` 1000 pounds per square inch. It leaves the coil through line 23 and valve 24 to catalytic reactor 35. Thejreaction products pass through line 25 and valve 31 to fractionator IB, which may suitably consist of a. separate Iractionator and stabilizer, but is shown as one vessel in the interest of simplifying the drawing. Catalytically cracked gasoline is removed through line I0 and valve II, being mixed with the raw oil charge in line 4 and thence treated as described above. A portion of the cracked gasoline may be withdrawn through line 29 and valve 60. A part of the insufficiently converted oil may be removed from the system through line 4i and valve' 42, and a part may be recirculated through line 43 and valve 44, which combines with line 25 and passes thence to the higher temperature catalytic cracking step. The gaseous: hydrocarbons are removed through line 45, valve 45, pump 41, valve 48 to polymerizer 4Q, wherein the oleins are converted to substantially gasoline boiling range material. The polymerized products are removed through line 50 andvalve 5i to stabilizer 02, from which the residual gases are removed trom line '58 and valve 54. Although a traction of the polymer may be; separately withdrawn through line and valve 56, according to the preferred operation the liquid polymer is withdrawn through line 51 and valve 58, combining with the raw oil charge inline i, and thence to e 4, through which it passes es previously oloscribed to the low temperature catalytic conversion step.

Substantially improved yields of high antilrncck, olen-free motor fuel which is stable in storage, .low in sulfur content, and has a high degree of susceptibility to added tetraethyl lead are produced in the manner described. This is illustrated by the following example which should not be interpreted as limiting the invention to the exact conditions employed. f

A Pennsylvania gasoil of 37.0 A. P.,I. gravity wasprocessed as described in the above specification the low temperature conversionstep being carried out at a temperature of 750 F. and a pressure of 100 pounds per square inch. Mixed with this oil was the catalytically cracked gasoline from the higher temperature conversion step which was operated at 930 F. 'Ihe charge from which the catalytically cracked gasoline was produced comprised the insumcientlyconverted oil from the lower temperature step. 'I'he gases from the higher temperature step were polymerized in the presence of solid phosphoric acid catalyst at a temperature of 410 F. and a pressure or 400 pounds per square inch. The polymer was mixed with the nraw oil charge and passedto the low temperature conversion step. The catalyst employed in bothhigh and low temperature converslpn steps was a substantially sodium-free silica-alumina-zirconia mass. The substantially olefin-free gasoline of 400 F. end point was recovered from the low temperature step. It had an octane number of 79, which was increased to f by the addition thereto ot d cc. of tetraethyl lead per' gallon. The total yield of gasoline system' through line 2 i and valve 2 2. Normally lo amounted to 81% ot the raw oil charge. The

2..lhoprocessasdeilnedinclaim1nn'ther.

gasoline had a bromine number o! Lan oxygen' bomb induction period in excess ot 24 hours. 1 milligram of copper-dish gum per 100 cc., and a `sulfur content oi' les than 0.01%.

We claim as our invention:

l. A process for producing substantially saturated gasoline of high anti-knock value which comprises combining oleiinic gasoline with hydrocarbon oil heavier than, gasoline, subjecting the resultant mixture to the action of a cracking catalyst at a temperature of about 60o-900 F., whereby to produce gasolineof, low olefin content, separating the low oleiin content gasoline from conversion products heavier than gasoline. catalytically cracking at least a portion of said heavier products at higher temperature than is maintained in the mst-mentioned conversion step, thereby forming olefnic gasoline. supplying the latter to the mst-mentioned conversion step as at least a. portion of the olenic gasoline which is combined with said hydrocarbon oil. subjecting olenie gas formed by the higher temperature catalytic conversion to polymerizaition and supplying resultant polymers to the first-mentioned conversion step.

characterisedinthatsaidheavierproductsaro cracked at a Otemperature of about 800-1200 F. 3. A process for producing substantially saturated of high anti-knock value whichu K comprises combining olennic gasoline with hydrocarbon oil heavier than gasoline, subjecting theresultantmixturetotheactionoiacracking catalyst at a temperature of about 60o-900 1P., whereby to produce gasoline oi' low olen oontent, separating the low olefin content gasoline from conversion products heavier than gasoline. cracking at least a portion of said heavier products at higher temperature than is maintained in the mst-mentioned conversion step. thereby formingoleilnic gas and gasoline, subjecting olennic gases thus formed to polymerization and supplying resultant oleiin polymers to the iirstmentioned conversion step as at least a portion of the olennic gasoline which is combined with Vsaid hydrocarbon oil.

CHARLES L. THOMAS.

s. BLocH.

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