US2466706A - Cracking hydrocarbons in the presence of fluoborate catalyst - Google Patents

Description

Patented Apr. 12, 1949 STATES UNITED PATENT OFFICE CRACKING HYDROCARBONS IN THE PRES- ENCE OF FLUOBORATE CATALYST No Drawing. Application March 13, 1946, Serial No. 654,218

3 Claims.

This invention relates to the conversion of h1gher molecular Weight hydrocarbons into lower molecular weight hydrocarbons, and more particularly to the manufacture of motor fuel by the conversion of such hydrocarbons in the presence of a catalyst comprising a fluoborate. The catalytic cracking of higher molecular weight hydrocarbons into hydrocarbons boiling in the motor fuel boiling range is well known in the art. The cracking is conducted in any of a variety of several procedural operations known in the art. Vapor phase cracking is the most common and several types of processes are in use. One is a fixed bed catalyst type in which the hydrocarbon vapors pass through the stationary catalyst bed or chamber. In the second type the catalyst is relatively finely divided or powdered and the catalyst powder is suspended in the stream of the hydrocarbon vapor undergoing treatment. This type is known as the fluidized catalyst process. In still another type the catalyst may be in pellets and may be recycled in a continuous type of process.

The catalytic cracking processes have been instrumental in making available large amounts of motor fuel and in some instances in making improved motor fuels such as those having high anti-knock ratings. One of the problems confronting the art is the production of a cracking catalyst which has a high cracking activity and which will yield the desired products. In many instances the production of coke and dry low boiling point gas in the cracking step is undesirably high. These products represent losses if the object is the production of motor fuel and it would be highly desirable to prevent or minimize their presence in the reaction product.

Other problems which confront the art include reducing the cost of the catalyst and increasing the active life of the catalyst during a single onstream period, and over a plurality of regeneration cycles.

It has now been found, in accordance with the invention, that a catalyst comprising a fluoborate is an active cracking catalyst. With this catalyst it is possible to obtain good yields of motor fuel boiling range hydrocarbons and reduced coke and dry gas production when this is desired. High grade motor fuel may be obtained with the catalyst.

The objects achieved by the invention include the provision of a process for converting higher molecular weight hydrocarbons into lower molecular weight hydrocarbons by treatment in the presence of a catalyst comprising a fluoborate; the provision of such cracking processes wherein the production of coke and dry gas may be relatively low; the provision of catalysts from readily available raw materials; the provision of a catalytic cracking processes which give good yields of 2 relatively high grade motor fuel; and other objects which will become apparent as the invention is described in more detail hereinafter.

It has been found, for example, that by treating higher molecular weight hydrocarbons which boil above the motor fuel boiling range in the presence of a catalyst comprising a fiuoborate, such as aluminum fiuoborate combined with alumina, that a high conversion of the hydrocarbon to the lower molecular weight hydrocarbons boiling in the motor fuel range may be obtained. In addition, the amount of coke and dry gas produced is materially lower than that obtained with known catalysts under similar conditions.

The process may be conducted in the usual manner known in the art for catalytic cracking, such as at either atmospheric pressures or higher or lower pressures. The process preferably is conducted at a reaction temperature of the order of about 800 to about 1000 F., and preferably at about 850 to about 950 F. The processes may be conducted in batch, intermittent or continuous manner, the vapor phase continuous manner being preferred. The flow rates, temperature, pressure, etc., are interrelated with reference to the specie of the catalyst used, the hydrocarbon starting material and the wanted products and yields, as will be apparent to one skilled in the art from the following examples. Dry gas may be included in the feed or charge to further minimize formation thereof, in accordance with mass action principles.

It is unexpected that the fluoborate catalysts of the invention would be active and yet markedly reduce the undesirable side reactions whereby coke, dry gas and butane are produced in vapor phase cracking processes. In addition, good yields of motor fuel of high quality are made available from higher boiling hydrocarbons by the cracking processes of the invention.

A fluoborate may be used as such as a catalyst, but preferably is supported on an insoluble support material, such as, for example, alumina, thoria, zirconia, silica, or clays. It may coact with the support, and the support may contribute to the cracking activity of the catalyst. The fiuoborate may be a salt containing the cation of a metal from any group of the periodic table, those of groups I, II and III being preferred. Typical salts are the fluobor ates of sodium, potassium, magnesium and aluminum. The catalyst may be prepared by any one of several methods. The fiuoborate may be prepared by metathesis, or by treatment of a metal salt or oxide with fluoboric acid and then added to or mixed with either the dry or a wet support ingredient. Alternatively both the fluoborate and the support ingredient may be co-formed and co-precipitated, or the fluoborate precipitated or deposited on the p senders; Its

' a ce. are i; 8 were added to preci gel. This was slurried in 13 liters additional water and filtered and washed until free of chloride. A pH of about 9 was maintained during the washing by adding NI-I4OH. The washed filter cake was divided in two parts and each part was reslurried in 10 liters distilled water. To one portion 28 grams of NaNOs and 64 grams of aqueous HBF4 were added to form NaBFi. To the other portion 29 grams KNOa and 56 grams of 45% aqueous HBF4 were added to form KBF4. The slurries were filtered and dried 24 hours at 150/ F. They were then further dried by heating to 1050/ F. and holding there for 10 hours.. The dried catalysts were crushed 4-14 mesh. The NaBFi preparation had a surface area of 322 square meters/gram and the KBF4 preparation an area of 301 square meters/gram.

Example 3 1250 grams commercial heavy alumina hydrate (AlzOa-3Hz0) was dissolved by adding 880 grams NaOH and a minimum of water and heating to boiling in a metal crucible, followed by dilution with 13 liters of distilled water. The alumina was then precipitated in a gelatinous form by adding 530 cc. of concentrated H2SO4 (98%) diluted with 3300 cc. of distilled Water. The precipitate was filtered and washed free of sulfate, and the washed filter cake was reslurried in 10 liters of water. To the slurry was added 70 grams of KOH and 236 grams of 45% aqueous I-IBF4, to make KBF4. The final volume of the slurry was 15 liters, and the pH was about 7. The slurry was filtered and the filter cake was dried at 150 for 24 hours and then at 1050 F. for 3 hours.

siirifiace area was /eram Afte sen i and:

m or. ii

enemies; is Est then poured off and the aluminum fiuoborate- I I alumina dried at 150 F. for 24 hours, then 3 hours at 1050 F. Its surface area measured 121 square meters per gram.

Example 7 An aqueous solution containing 67.5 grams of magnesium fluoborate in 300 cc. H2O was poured over 200 grams commercial activated alumina of 8 to 14 mesh, subjected to a vacuum for five minutes, allowed to stand at atmospheric pressure for five minutes and this cycle was repeated four times to assist the absorption of the fluoborate on the alumina. The excess liquid was then poured off and the magnesium fiuoboratealumina dried at 150 F. for 24 hours, then 3 hours at 1050 F. Its surface area measured square meters per gram.

The following examples describe cracking processes in accordance with the invention using various fluoborate catalysts such as described previously.

Example 8 A 3l A. P. I. gas oil was treated in a fixed bed type of catalytic apparatus at atmospheric pressure, a temperature of 800 F., and a flow rate of 1.5 in the presence of an Al(BF4)3-alun1ina catalyst (prepared in accordance with the method of Example 6.) A 44 volume per cent yield of liquids boiling up to 410 F. was obtained based on the feed.

Example 9 Following the procedure of Example 8, using a Ni (BFQz-alumina catalyst (prepared in accordance with the method of Example 5), a 36.7 volume per cent yield of products boiling up to 410 F. was obtained.

Good yields were also obtained using potassium fluoborate-alumina, sodium fluoborate-alumina, chromium fluoborate-alumina, and magnesium fluoborate-alumina in the above fixed bed operations.

Example 10 A 34 F. A. P. I. gas oil was treated in a laboratory scale fluidized catalyst apparatus, charging 600 cc. of 40 to 100 mesh powdered aluminum fluoborate-alumina catalyst of the invention (prepared in accordance with the method of Example 6 except that the alumina was first ground to 40 to 100 mesh) at atmospheric pressure, a temperature of 900 F., and a flow rate of 1.04 for an on-stream time of 0.5 hour. A 31.6% by volume yield of liquid product containing at least six carbon atoms and boiling up to 410 F. (i. e. 06-410 F. liquid) was obtained (a 55% by volume C4-410 F. liquid was obtained). This is substantially higher than the yields obtained with commercially available catalysts tested under similar conditions. The (Is-410 F. product showed an octane rating of 88.6 by the CFR-Research method (Coordinating Research Council designation F-1-545). The 10 RVP gasoline has an octane number of 92 CFR- R. This is indicative of a very valuable motor fuel. At temperatures of 850 F., and of 950 F., the yield was slightly lower. The octane rating of the 06-410 boiling range product obtained at 850 F. was slightly lower and that obtained at 950 F. was slightly higher than the above 900 F. product.

Good conversions were obtained with potassium fluoborate-alumina catalyst and with chromium fluoborate-alumina catalyst under similar conditions. The potassium fluoborate 900 F. Ce 410 F. boiling range product showed an octane rating of 93.2 by the published CFR- Research method. The chromium fluoborate 950 F. C's-410 F. boiling range product showed an octane rating of 93.6 by the published CFR- Research method.

Example 11 In order to compare the amounts of coke, dry gas, and butane by-products in vapor phase catalytic cracking processes using the catalyst of the invention with processes using commercially available catalysts, 34 A. P. I. gas oil was treated in the presence of the catalysts, at equal conversion levels (about 52.0 weight per cent yield based on weight of charge). The following results were obtained:

Data reported based upon amount of C410 F. gasoline produced (e. g. 10.7 lbs. of coke pro- It is evident from the foregoing data that the aluminum fluoborate-alumina catalyst of the invention is markedly superior to the commercial vapor phase catalyst of either the fixed bed or the fluidized catalyst type as to minimizing undesirable coke, dry gas, and butane production.

In view of the foregoing disclosure, modifications and variations thereof may be apparent to one skilled in the art. The invention includes all such modifications and variations as come within the scope of the appended claims.

We claim:

1. A method of converting higher molecular weight hydrocarbons into lower molecular weight hydrocarbons including hydrocarbons of motor fuel boiling range, which comprises subjecting hydrocarbons boiling above the motor fuel range to contact with an active catalyst comprising a metal fluoborate of a metal of the group consisting of sodium and potassium under cracking conditions such that substantial conversion of feed hydrocarbons to motor fuel boiling range hydrocarbons is obtained.

2. A method of converting higher molecular weight hydrocarbons into lower molecular weight hydrocarbons including hydrocarbons of motor fuel boiling range, which comprises subjecting higher molecular weight hydrocarbons to contact with an active catalyst comprising a metal fluoborate of a metal of the group consisting of sodium and potassium supported on alumina under cracking conditions such that substantial conversion of feed hydrocarbons to motor fuel boiling range is obtained.

3. A method of converting higher molecular weight hydrocarbons into lower molecular weight hydrocarbons including hydrocarbons of motor fuel boiling range, which comprises subjecting higher molecular weight hydrocarbons to contact with an active catalyst comprising a potassium fluoborate supported on alumina under cracking conditions such that substantial conversion of feed hydrocarbons to motor fuel boiling range is obtained, said catalyst containing an amount of the fluoborate in the range of 5 to 15 weight per cent.

EVERETT C. HUGHES. SAMUEL M. DARLING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,339,302 Thomas et a1. Jan. 18, 1944 2,346,012 Danforth Apr. 4, 1944 2,398,773 Connolly Apr. 23, 1946 OTHER REFERENCES Mellor, Comprehensive Treatise on Inorganic and Theoretical Chemistry (vol. 5, pp. -128), Longmans, Green 8; Co., London, 1924.

Searle Chemistry and Physics of Clays" (pages 413-414) Ernest Benn Ltd., 1933.

Certificate of Correction Patent No. 2,466,706. April 12, 1949.

EVERETT o. HUGHES ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 1, line 59, strike out a after the Words provision of; column 3, line 23, for KMO read KNO line 29, for to after dried read at; line 52, for 150/ F. read 150 F.; line 53, for 1050/ F. read 1050 F'.; column 4, line 26, for 150 read 150 F.; column 5, line 7, after above insert type;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this, 13th day of September, A. D. 1949.

JOE E. DANIELS,

Aasz'stwnt Uommz'asioner of Patents.

Certificate of Correction Patent No. 2,466,706. April 12, 1949.

EVERETT o. HUGHES ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 1, line 59, strike out a after the Words provision of; column 3, line 23, for KMO read KNO line 29, for to after dried read at; line 52, for 150/ F. read 150 F.; line 53, for 1050/ F. read 1050 F'.; column 4, line 26, for 150 read 150 F.; column 5, line 7, after above insert type;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this, 13th day of September, A. D. 1949.

JOE E. DANIELS,

Aasz'stwnt Uommz'asioner of Patents.

Certificate of Correction Patent No. 2,466,706. Aprll 12, 1949.

EVERETT o. HUGHES ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 1, line 59, strike out a after the words provision of; column 3, line 23, for KMO read KNO line 29, for to after dried read at; line 52, for "150/ F. read 150 F.; line 53, for 1050/ F. read 1050 F'.; column 4, line 26, for 150 read 150 F.; column 5, line 7, after above insert type,

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this, 13th day of September, A.- D. 1949.

JOE E. DANIELS,

Assistant Oomnz'aaioner of Patents.