DE1084248B - Process for the production of abrasion-resistant, catalytically active compounds from clay minerals - Google Patents

Description

Process for the production of abrasion-resistant, catalytically active compounds from clay minerals The invention relates to a process for the production of abrasion-resistant, catalytically active masses, which are also useful as adsorbents, from Powdery mixtures of an acid-treated bentonite plasticized with water and another clay mineral by molding, drying and calcining, optionally with catalytically active substances are added, and is characterized in that as another clay mineral, finely divided kaolin clay in an amount of 5 to 35 percent by weight, based on the dry mixture of kaolin and bentonite.

It is known to produce hard and porous, adsorptive or catalytically active granular or shaped masses of alumina jelly or their Dry products that are practically free of silica, a strong mechanical Subject to treatment until the formation of a homogeneous and thin paste and then, optionally after previous deformation, to dry, the mechanical Treatment takes place without additives or with the participation of peptizers. To Another known method produces dimensionally stable catalysts from one Mixture of bentonite, which is largely digested with acid, and undigested bentonite Raw clay, optionally with the addition of catalytically active substances, which you can use with or kneaded without water until a thick paste is formed, this after deforming dries and, for the purpose of further consolidation, optionally in a gas stream at higher temperatures Temperatures aftertreated, or that acids or alkalis of the catalytic Mass clogs. In these known processes, it is expedient to use such a method Raw clay similar to that from which the digested material is obtained was e.g. B. Raw Bentonite.

In contrast, the invention concerns the application of powdery kaolin clay mixed with acid-treated bentonite; the advantage lies in the fact that one can produce abrasion-resistant masses with much smaller amounts of kaolin is sufficient compared with the abrasion resistance for the production of masses comparable required amounts of raw bentonite.

The addition of alumina increases the adsorption capacity and the catalytic properties Activity of the masses obtainable by the process of the invention in reforming reactions, in isomerizations and cyclizations. Hydrogenation, dehydrogenation, aromatization, Desulfurization, removal of nitrogen and the like can be carried out with the inventive manufactured catalysts perform if for them during manufacture heavy metal oxides known per se for these purposes are incorporated. For these uses are the achieved bulk density and hardness (abrasion resistance), the resistance at mechanical handling during storage, transport and Use of crucial Meaning. Such products can be in the form of fixed beds or moving layers as well as in catalytic fluidized bed processes where they depending on requirements and expediency in the form of certain particle size and distribution, such as B. as platelets, tablets or as a powder, are introduced into the reactor ; they are highly effective and active and, because of their hardness, withstand all mechanical ones and chemical stresses, such as B. Shock and abrasion forces, pressure and steam effects, and can be easily and quickly regenerated after reaching the state of exhaustion, keeping their original shape and particle size unchanged.

The powdered substances are used for tabletting, which also include a Lubricants such as B. graphite, may be added, preferably in practical used when dry. The obtained tablets are used for activation of the catalytic substances and for the purpose of burning out the lubricant or lubricant calcined. It can be hard, adsorptive tablets with a smooth surface any size you want.

In the case of deformation by extrusion, the first step is to use the powdered material with the addition of a sufficient amount of water or another Liquid produces a paste-like mass, compresses it through nozzles as desired Size and shape and divides the compact into cookies at regular intervals desired length, then dries and calcines them. Here is the addition a lubricant or lubricant, which may only be removed by burning away would have to be, seldom required.

With both methods, any desired pressure can be used for the shaping be applied. Such catalytically active adsorbent substances, such as. B. Alumina, which in itself is difficult to extrude when moist, are added to the clay mixture in the method according to the invention for each type of shaping, especially suitable for extrusion, without sacrificing any of their catalytic properties Activity, adsorbability, hardness and great resistance to pressure and To forfeit the effects of abrasion.

The compositions obtainable according to the invention show compressed, dried and calcines a degree of hardness that is greater than the degree of hardness of masses, which are made from each clay component alone or with other proportions of both clays will. This relationship between particle hardness and composition is shown in Fig. 1 emerged. It can be seen that a climax of severity is reached when the Mass between 85 and 90 ° / 0 of a bentonite clay washed with acid (cf. details in column 5. It was found that this is the optimal relationship in terms of the proportions is also retained when other substances, such as Alumina or molybdenum oxide, can be introduced into the mixture.

The quality of the hardness or the abrasion resistance was here with the help an abrasion loss apparatus determined.

The apparatus consisted of a cylindrical metal canister in which two up to the walls of the cylinder reaching baffle plates were axially attached, wherein each of these baffles inside to about half the radius of the metal can extended, and which was then set in rotation in a horizontal position. There were 100 g of catalyst particles placed in the can and at 60 rpm. the can 1 hour treated. The solid material was then taken out and used to separate the Fine sieved with a particle size below about 840 li. The collected fine was weighed and the abrasion loss A expressed as the weight of the fine. p0. original Particle Weight The hardness of the particle can be expressed as H = 100-A.

This value thus represents the weight percent of the original Material that was not rubbed off by the particles during the experiment.

The hardness values calculated here all represent the hardness of the finished calcined particles that differ from that of the only (e.g. at 120 to 205 ° C) dried particles is different. So the hardness here came from particles determined that have been heated to 315 to 815 ° C for 1 to 16 hours, with a Part of the bound water is removed and usually the mass is removed their crystal structure is activated.

The activated bentonite-like clays and the kaolin-like clays used here Clays can be different from each other and from other clays due to one of the many different Properties can be distinguished. The bentonite clays contain in the raw state a high proportion of montmorillonite-like minerals, including montmorillonite, Beidellite, nontronite, hectorite, saponite and sauconite. Montmorillonite is often called Designated as Os-4 SiOs-HO + HgO. Kaolin clays are rich in kaolin minerals, including Kaolinite (X203'2 SiO2 2 H2O), dichite, nacrite, anauxite, hallyosit and endellite and un- usually hold about 30 to 40% A1203, but bentonite clays usually less than 20% of it. Another important property of bentonite clays is their high, usually between 80 round 90 milliequivalents per 100 grams of the air dry clay lying cation exchange capacity; the crystal lattice is apparently weak bound. On the other hand, kaolin clays have a low cation exchange capacity on the order of 10 milliequivalents per 100 grams of dry clay.

According to the X-ray diagram, montmorillonite minerals have three layer lattices, Kaolin minerals, on the other hand, have a two-layer crystal lattice. The curves of the differential Thermal analysis of the montmorillonite (cf.

W. J. Smothers and Yao Chiang, Differential Thermal Analysis, Chemical Publishing Company, New York, 1958) show three endothermic peaks at 150 to 320, 695 to 730 and 870 up to 920 ° C and an exothermic peak at 925 to 1050 ° C. The analog curves for Kaolinite show a strong endothermic peak at 620 ° C and a strong exothermic Peak at 980 ° C, which clearly distinguishes it from other groups of clay minerals (See also R. E. Kirk in Encyclopedia of Chemical Technology, Vol. 4, p. 24 to 85 [Interscience Encyclopedia Inc., New York, 1949]).

The non-swelling or sub-bentonite tones used here are among others in Arizona, California, Texas, Arkansas, Mississippi, Kentucky and Tennessee, swellable bentonite found in Wyoming, South Dakota, Montana, Utah, Nevada and California.

In the process according to the invention, preference is given to using the non-swelling or sub-bentonites because they can be activated more easily (e.g. by washing with acid) than swelling varieties. Therefore, a high quality sub-bentonite clay is preferred, in which the mineral montmorillonite predominates. These clays are usually activated by treatment with a mineral acid such as sulfuric acid. 45 kg of the dry clay can e.g. B. be treated with about 9 to 68 kg H2SO4. The acid strength can be about 5 to 60% based on the total water content of the mixture including the water content of the clay. The treatment time extends over about 1 to 12 hours at a temperature fluctuating between about -17 and 100 ° C. The acid treatment is preferably carried out until the final content of A1203 plus FOg in the bentonite is between 10 and 20%, preferably between about 15 and 20%. 45 kg of a typical Arizona sub-bentonite can e.g. B. Treat with 13.60kg H2SO4 as a 12% solution for 6 hours at 93 to 100 ° C. Analyzes of the original clay and the acid-treated product showed the following on a dry weight basis: Before after after Treatment treatment Weight percent weight percent Six2 67.3 71, 5 AI, O ........... 19.5 16.3 F, 1, 8 2, 4 cao ........... 3, 2 2, 3 6, 6, 94, 5 If the catalyst is to be used to treat hydrocarbons with a high sulfur content, then it is desirable to reduce the Fe2O3 content of the bentonite clay to as low a value as possible, preferably below about 1%. In this way, the catalyst is made far more resistant to sulfur poisoning and maintains its activity over a longer period of time.

The A12O3 ll and Fe203 content should not be caused by acid treatment can be reduced below about 10% if the molding is in the further manufacturing process of the catalyst should be done by extrusion, since treated more strongly with acid Clays lose their malleability (plasticity) and thus their ability to be squeezed out.

Very useful clays according to these guidelines are available in stores. Such has z. B. in the calcined state the following composition: sio, ...................... 70 A1203 17 Fe203 2 MgO ........... ........... 5 CaO ....................... 3 H20 ............ .......... 3 The kaolin clays used here come e.g. B. in North Carolina, South Carolina, Georgia, Florida and Vermont. A variant of the highly plastic kaolin, known as ball clay, is found primarily in Tennessee, Kentucky and New Jersey and is particularly suitable for the process of the invention. Usually, these kaolin clays do not require any special pre-treatment other than grinding to pulverize all coarse aggregates. At times, dilute acid washing may be desirable. A suitable ball clay is that of the Western Talc Company, Los Angles, California, which gives the following analysis: SiO2 51.6 A1203 33.7 Fe203 0.8 CaO ................ .... 0.14 MgO ................... 0.27 Ho 11.9 Example I The values shown in Fig. 1 and Table 1 were obtained when processing the obtained ball clay type and the aforementioned acid-treated bentonite clay with 17% Al 2 O 3 content by the process according to the invention. In all cases, the masses were prepared by first mixing the specified proportions (calculated on the calcined material) of the two clays in powder form, adding enough water to obtain a plastic, malleable mass and then applying this under a pressure of about 14 kg / cm2 extruded circular openings 4.75 mm in diameter. The extruded mass was cut into pieces 4.75 mm long, dried at about 105 ° C. and calcined at about 595 ° C. for 2 to 6 hours. The hardness was then determined as indicated above. The following resulted: Table 1 Composition in percent of the dry weight -Acid hardness lysator-treated ball clay Bentonite abrasion loss 0 100 93, 4th 2 50 50 98, 0 3 75 25 98, 9 4 85 15 99, 3 5 100 0 98, 7 The material, which contains 85% acid-treated bentonite and 15% all clay and is designated in FIG. 1 as "mixture A", can be used particularly advantageously as a cracking catalyst.

This clay mass can also be used in the refining of gas oil. At a temperature of about 370 ° C, atmospheric pressure and a catalyst-oil ratio from 5.0 70 to 85% of the organic nitrogen compounds are removed; at the treatment of a nitrogen-containing light gasoline at 205 ° C, atmospheric pressure and a catalyst to oil ratio of 1.0 will both be 60 to 80% of the nitrogen compounds as well as most of the polymerizable diolefins.

Refractory oxides such as B. precipitated gel-like clay, silica, Silica-alumina, titanium oxide, thorium oxide, zirconium oxide or magnesium oxide, the are not extrudable per se, the clay mixture described above in quantities from 30 to 90 percent by weight (calculated on calcined material) during the Production of catalytically active compositions added by the process according to the invention and thus converted into easily squeezable mixtures. Here again is the relative proportion of the two clays in the finished cookie is an important factor, wherein mixtures with a weight ratio of bentonite to kaolin of about 2.5 up to 20 are harder than those containing other proportions. aside from that But there is another important factor, namely the particle size of the used Clay, on. It has been found that the hardness of the cookies increases with use finer alumina increases. For example, a mixture consisting of 50% alumina can be used maximum particle size of 62μ, 42.5 Ω / □, slure treated bentonite clay and 7.5 ° / 0 Ball Cay is composed, moistened until malleable, as described, extruded into 4.75 mm cookies, dried and kept at 595 ° C for 10 hours are calcined, whereupon their hardness with the abrasion loss apparatus described above is determined. The hardness of such cookies is in the range between about 97.25 and 97.8, whereas the hardness of the same moldings made of alumina of one particle size up to 43, (between 98.25 and 99. This is why the use of clays or other refractory oxides with an average particle size below 50 in preferred.

The hardness of the clay-alumina masses also increases somewhat with one Increase in the total clay mixture content of the catalyst to over 50 "/. Mixtures made of 50% clay and 50% clay (85% acid-treated bentonite, 15% ball clay) when they are manufactured and examined as described above give a hardness of about 97.5, while similar mixtures consisted of only 30% of the clay and 70% of the clay mixture have a hardness of about 97.8. This small increase in hardness becomes common outweighed by the loss of activity of the alumina component, which is why one is clay-alumina catalysts preferably containing between about 40 and 65 "/ o alumina.

The clay-alumina catalysts are primarily involved in conversions usable, which do not predominantly concern hydrogenation and dehydrogenation reactions, so z. B. for splitting, isomerizing or reforming various hydrocarbon fractions at temperatures from about 480 to 650 ° C, pressures from 0 to 70 kg / cm2 and hourly Throughput rates (volume of hydrocarbon per volume of catalyst per Hour) from about 0.5 to 10.0. They are also ideally suited for adsorption processes.

Clay-alumina-heavy metal masses in a preferred embodiment of the method according to the invention are the clay mixture in addition to the clay Oxide or several oxides of heavy metals with an ordinal number of 22 or above, to which the metals of Groups VI and VIII of the Periodic system, especially chromium, molybdenum, tungsten, uranium, iron, ruthenium, Osmium, cobalt, rhodium, iridium, nickel, palladium and platinum include.

A particularly valuable group of catalysts for conversion processes, where it is desired to accelerate the hydrogenation and / or dehydration, is that which contains an oxide of molybdenum or chromium.

The 'oxides of cobalt and nickel are special alongside these metal oxides then advantageously contained in the catalysts if the starting material has a high content of organic sulfur compounds. Catalysts of this Groups can be prepared by one of the two methods described below will.

Method 1: The composite clay mass, which preferably consists of about 70 to 95% of the bentonite-like clay and 5 to 30 ° / 0 of the kaolin-like clay, is made with clay and a finely divided oxide from at least one of the to be used Heavy metal oxides, e.g. B. mixed with molybdenum oxide. This mixture is then up made into a paste for moldability with any liquid suitable for this purpose, as above described extruded, dried to form cookies of the appropriate size and calcined. After drying or calcining, it may be desirable to use the catalyst furthermore with an aqueous solution of another metal salt, e.g. B. Cobalt Nitrate or nickel nitrate. The impregnated catalyst will then drain off left, dried and fully calcined to remove the penetrated metal salt into the To transfer oxide form.

Method 2: Here are all the components that are in the finished Catalyst should be included, intimately mixed together, whereupon the Mixture z. B. is shaped by extrusion into cookies and then dried and calcined. You can z. B. clay, alumina and dry molybdenum oxide (Mo 03) ground together and with an aqueous solution of cobalt nitrate or Nickel nitrate of sufficient strength to make the desired ratio of cobalt or To achieve nickel oxide in the calcined catalyst when the solution is in a just sufficient amount is used to make the mixture necessary for extrusion to impart desired formability. After another amendment, everyone can heavy metals to be used in the form of an aqueous solution of the salt or the Salts can be added. For this purpose, ammoniacal ammonium molybdate or Ammonium chromate or, in general, any other heavy metal salt that can be obtained by heating can convert to 260 to 650 ° C in the oxide in question.

Molybdenum- and cobalt-containing catalysts from one of the two processes can have the following final composition after calcining: alumina ..................... 35 to 65 0 /, bentonite clay ................. 20 to 45 ° / 0 kaolin clay ................... 2.5 to 12 ° / 0 molybdenum oxide 5 to 15 ° / o cobalt oxide .................. 1 to 6 0 /, Compressed catalysts have been found to be within the above compositional range have practically the same hardness as clay-alumina catalysts; Heavy metal oxides do not noticeably affect the hardness within the above range of the proportions.

Your activity for hydrocarbon conversions, such as hydroforming, Hydrogenation, dehydration, flavoring, desulphurisation and removal of nitrogen, is with that of cobalt-molybdenum-alumina catalysts that are after previous procedure were produced, absolutely comparable.

The graph of FIG. 2 gives the dependence of the hardness on the particle size of the Al203 in the molybdenum-containing catalysts and also the relative hardness of such catalysts again, the different ratios of alumina to contain clay and acid-treated bentonite clay to make Ball Clay. The in-depth meaning this drawing can be seen in the following example.

Example II Catalysts of the composition given in Table 2 were activated by intimately mixing alumina gel in the specified proportions of clays and powdered molybdenum trioxide, adding one for plasticizing adequate amount of water and extruding through circular openings with a 4.75 mm in diameter. The extruded material became pieces 4.75 mm long, cut, dried, calcined at 595 ° C. for about 7 hours and then its hardness is determined in the abrasion apparatus described above. The results are listed in Table 2.

Table 2 Composition in percent of dry weight A1a03 Saurebe- Kata-particle-particle-traded claa Mo ° 3 hardness large to b oBe to bentonite y to 62 p to 43 p ~ 1 30-51 9 10 97, 8 2 50-34 6 10 97.5 3-50 34 6 10 98.5 4-50 34 6 10 98.4 5-50 40-10 96.1 The influence of the different particle sizes of the alumina on the hardness in the case of catalysts 2, 3 and 4 can be seen particularly clearly from FIG. The catalyst 1 has a slight increase in hardness compared to that of the catalyst 2 because of the higher clay content. Catalyst 5 strikingly shows the effect of the absence of the kaolin clay in the mass; the hardness is reduced by more than two units compared to catalysts 3 and 4.

Example III That for the preparation of the catalysts 3 and 4 in the example The procedure used is repeated, followed by immersion of the catalyst impregnated with cobalt in a 20% aqueous solution of cobalt nitrate hexahydrate, drained, dried and again at 595 ° C for 6 hours for the purpose of transfer of the salt calcined in cobalt oxide. The finished catalyst contains about 30/0 COO. The hardness (as measured above) was about 98.6 with the slight improvement probably due to the second calcining.

Example IV A nickel-alumina-clay catalyst is prepared by first mixing 210 g of acid-treated bentonite with 24 g of ball clay to form a uniform Powder mixed.

The clay mixture is then thoroughly precipitated, activated with 200 g Alumina (particle size up to 45 li) and 40 g dry, powdered molybdenum trioxide mixed up. The dry mixture is then mixed with 150 g of a 40% aqueous solution made of nickel nitrate hexahydrate.

This creates a stiff paste, which then passes through nozzles 4.75 mm in diameter and extruded under a pressure of 14 kg / cm2 and then cut into pieces 3.17 mm in length. After drying and Calcining for 8 hours at 650 ° C. results in cookies with a loss due to abrasion certain hardness of about 97 and the following composition (dry weight): percent by weight Acid-Treated Bentonite ............. 49.0 Ballton .............................. 4.2 t112Og ................................ 44.0 MoOg .......... ...................... 8.9 NiO ................................. 3.5 All in Examples II, III and IV shown catalysts and other similar masses containing one or more heavy metal oxides are particularly useful for the various hydrocarbon conversion reactions, such as refining, hydrogenation, hydroforming, reforming, cracking, crack hydrogenation and the like suitable.

With such conversions, alternating ones accumulate during operation Lots of debris, mostly made up of carbon, nitrogen and sulfur compounds insist on the catalyst, from which it periodically burns off be removed with air. The regenerated catalyst has after the reduction Hydrogen has practically the same catalytic activity as the freshly made one Catalyst even after a large number of regenerations.

PATENT CLAIMS: 1. Process for the production of abrasion-resistant, catalytic acting masses of powdered mixtures of an acid-treated one plasticized with water Bentonite and another clay mineral by molding, drying and calcining, where, if necessary, catalytically active substances are added, characterized in that that as another clay mineral, finely divided kaolin clay in an amount of 5 to 35 ge weight percentage, based on the dry mixture of kaolin and bentonite.

Claims (1)

2. The method according to claim 1, characterized in that the Clay mixture a finely divided oxide gel from the group of silica, alumina, silica-alumina, Titanium oxide, thorium oxide, zirconium oxide and magnesium oxide in such quantities under homogeneous Mixing adds that 30 to 90 percent by weight of this oxide gel in the end product are present. 3. The method according to claim 2, characterized in that 22.5 up to 57 percent by weight clay mixture, 35 to 65 percent by weight oxide gel and 6 to 21 Percentage by weight of a catalytically active, finely divided oxide of a metal Group VI and / or Group VIII mixed homogeneously with one another. 4. The method according to claim 3, characterized in that as catalytically active oxide 5 to 15 percent by weight molybdenum oxide used. 5. The method according to claim 4, characterized in that one also Introduces 1 to 6 weight percent cobalt oxide. 6. The method according to claim 2 to 5, characterized in that the Oxydgel is a powdered clay gel with an average particle size below 50 p is. 7. The method according to claim 3 to 6, characterized in that one an aqueous solution of a metal salt with the other components before they are deformed and drying, and then the mixture of masses to form the calcined catalytically active metal oxide. 8. The method according to claim 3 to 6, characterized in that one the preformed and dried clay mixture with an aqueous solution of a Metal salt impregnated and that one then again dried and calcined. Considered publications: German Patent Specifications No. 664 817, 742 196.