DE886897C - Process for the production of low-boiling hydrocarbons from higher-boiling hydrocarbons by catalytic cracking - Google Patents

Description

Process for the production of low-boiling hydrocarbons Higher-boiling hydrocarbons by catalytic cleavage. It is known that higher-boiling hydrocarbons Hydrocarbon oils by catalytic treatment with hydrogen at increased Temperature and pressure in the presence of alumina with fluorine or hydrogen fluoride is pretreated to be converted into low-boiling hydrocarbons. The catalyst can also serve as a carrier for oxides or sulfides of the metals of the 5th or 6th group.

It has now been found that in this process the yield of low-boiling hydrocarbons and the knock resistance of the gasoline can be increased and the operating time can be extended until the catalyst is reduced if active alumina or aluminum hydroxide with an iron group metal is used in the preparation of the catalyst or a connection of such a metal. The alumina or the aluminum hydroxide can be combined with this metal or one of its compounds in a dry or moist state; in particular, the alumina or the hydroxide can be impregnated with salt solutions of the metal of the iron group. Mixing with the metal or the metal compound can also be carried out in the dry state and the mixture can be shaped by pressing. Iron in particular comes into consideration as the metal of the iron group. But you can also use nickel and cobalt. In general, 0.5 to q0%, advantageously 2 to about 20%, of the metal of the iron group, based on the alumina, are used. As active alumina, those commercially available and described in the literature can be used. The aluminum hydroxide can be produced in any desired manner from aluminum salt solutions or aluminate solutions. In general, preference is given to those hydroxides which, at elevated temperature, in particular above 50 °, e.g. B. from 75 to 100 °, and with a pq between 7 and io are generated. The separation of the precipitate is also expediently carried out at an elevated temperature, e.g. B. 3o to 50 °.

The alumina hydrate, which is made from aluminum sulfate and sulfite was, is appropriate with ammonia solution of more than 6o °, advantageously more than 8o °, treated, e.g. B. by adding the hydrate to this solution, which for some Time is kept at temperatures of 70 to 100 °.

If you start from an aluminate solution, the hydroxide will fall through Add acid until a pn value below 7 is reached.

It is also advantageous if the aluminum salt or aluminate solution obtained precipitate, optionally after predrying, with acid, for. B. a mineral acid, is peptized into a dough or slurry.

When using alkali solutions as precipitants, it is advisable to the precipitation in the presence of water-soluble compounds of polyvalent, in particular divalent metals, especially those of the 2nd group of the periodic table, z. B. the chlorides or nitrates of zinc, magnesium, cadmium, beryllium, calcium, Strontiums and Bariums. This is where you use so much of a solution of the salt of the divalent ': metal that the alkali excess is practically complete is bound to the acid residue of the added salt of the divalent metal and the alkaline reaction. the solution by the formed hydroxide of the bivalent Metal is generated.

The z. B. Catalyst produced by impregnation is dried, washed and heated to temperatures of 40o to 8oo ° and now with fluorine or a volatile fluorine compound, especially hydrogen fluoride or ammonium fluoride Treated ordinary or advantageously elevated temperature.

But you can also treat the alumina or aluminum hydroxide with fluorine Carry out in the moist or dried state and only then the metal of the iron group or its connection, e.g. B. by soaking with the salt solution or mixing with the metal or metal compound. Then the catalyst dried and heated to a higher temperature so that the metal is essentially is present as an oxide, which is optionally converted into the metal by reduction can be.

The catalyst can also have a during or after its production small amount of active silica or a synthetically produced silicate, both of which were advantageously generated at a pu below 7, or activated with acid Fuller's earth in an amount of 0.5 to 20%, advantageously r to 15%, is added will. These can also be treated beforehand with fluorine or with a fluorine compound will. Furthermore, you can the catalyst, even small amounts of a fluoride, for. B. of aluminum or magnesium.

If the metal of the iron group or its compound is added before the fluorine treatment, the catalyst can be treated again with a metal of the iron group or its compound, e.g. B. in an amount of 0.5 to 15%, based on the total catalyst provided. If necessary, a further treatment with fluorine or a volatile fluorine compound can then take place.

The cleavage of the hydrocarbons is carried out in the presence of hydrogen under a pressure of 2 to 100 atmospheres, advantageously 20 to 10,000 atmospheres, expediently 40 to 100 atmospheres. The hydrogen partial pressure should be from 20 to 95 %, advantageously from 20 to 20%, of the total pressure.

The hydrogen-containing reaction gas is advantageously fed back into the reaction chamber, e.g. B. in an amount of 0.5 to 5, in particular 0.7 to 4 cbm per kilogram of starting material.

Heavy oils, middle oils, heavy petrol and petrol are used as starting materials and also oil residues into account. The starting materials can be obtained by distillation, Cleavage, synthesis, pressure hydrogenation or polymerization can be obtained.

The catalyst can be arranged permanently in the reaction space or through it be moved. The reaction temperature is from 35o to 500 °, in particular from 38o to 48o °. The reaction can take place in the presence of acidic substances such as hydrogen halide, Ammonium halide, e.g. B. ammonium chloride or ammonium fluoride, or hydrogen sulfide, be performed.

After its completion, the catalyst can still be used as a support for Metals of group 5 or 6 of the periodic table or their compounds or or and serve for metals or compounds of the platinum group. Will he still z. B. with a small amount of platinum, palladium, ruthenium, molybdenum, chromium, tungsten and or or vanadium or its compounds are provided in the case of the described Procedure, e.g. B. in the treatment of heavy gasoline, in addition to the split also a Reform achieved. Mixtures of these metals or their compounds can also be used here raise. So are z. B. larger amounts of the oxides or sulfides of the metals the s. or 6th group with smaller amounts of platinum, palladium or ruthenium.

Sometimes it is beneficial to use the raw material before treatment in the manner described at an elevated temperature through a vessel with Adsorption masses, e.g. B. pumice stone, pottery shards, bauxite or fuller's earth, or with Raschig rings is filled, or the sulfur-binding metals, e.g. B. copper, molybdenum, Tungsten, nickel, cobalt, lead or their compounds.

Example An active clay produced by precipitation from aluminate solution is soaked in so much iron nitrate solution that one hundred and seventy percent of the weight of the clay appropriate Amount of Fe203 is retained. After drying at iio 'it is 48 hours at 40 ° calcined. The material, shaped into pills, is mixed with dilute HF (122 g 70% HF soaked in 11 water per kg), dried at 80 ° and calcined at 40 ° for 8 hours.

Over 500 cm3 of this catalyst is passed at 400 "and at a hydrogen pressure of 70 at an hourly 25o cm3 of a medium oil (boiling point 200 to 3.40 ', aniline point 71 °) from Arabian petroleum, with 01 iooo 1 hydrogen per kilogram (measured cold) through the A reaction product is obtained which contains 57% gasoline after the first hour of operation and 31% gasoline after the first hour of operation with an octane number of 75. The yield of liquid product is 93 % of the middle oil used After the 4th hour of operation, the oil supply is switched off and the catalyst is regenerated in a hydrogen stream.

Claims (7)

PATENT CLAIMS: i. Process for the production of low-boiling hydrocarbons from higher-boiling ones by catalytic cleavage in the presence of hydrogen under increased pressure, in particular from 2 to 100 atmospheres, and temperatures from 35o to 55o °, characterized in that a catalyst is used in the production of which active alumina or aluminum hydroxide is used provided with a metal of the iron group or a compound thereof and previously or afterwards treated with fluorine or a volatile fluorine compound and then advantageously also one or more metals or one or more compounds of metals of the 5th, 6th or platinum group of the periodic System were added. 2. Procedure according to Claim i, characterized in that in the manufacture of the to be used Catalyst when adding the metal of the iron group or its compound before the Fluorine treatment was followed by such an addition again after this treatment. 3. The method according to claim i and 2, characterized in that the to be used Catalyst a small amount of an active silica, an artificially produced one Silicate or an activated fuller's earth was added. q .. Process according to Claims 1 to 3, characterized in that the hydrogen-containing reaction gases are returned to the reaction space in an amount of 0.5 to 5 cbm per kilogram of starting material. 5. The method according to claim i to q., Characterized in that at the preparation of the catalyst to be used that for the production of the aluminum hydroxide Serving aluminum salt solution or aluminate solution at elevated temperature, expedient above 50 °, advantageously between 75 and 100 °, and useful with a pil over 7 was felled. 6. The method according to claim i to 5, characterized in that in the preparation of the catalyst to be used from the aluminum salt or the precipitate obtained from aluminate solution was peptized with acid. 7. The method according to claim i to 6, characterized in that a total pressure of 2o to 100 atm and expediently a hydrogen partial pressure which is 2o to 95 % of the total pressure is used.