DE4209292A1 - Spent metal and/or oxide catalyst regeneration by mechanical crushing - with specified energy density, esp. for catalyst used in oxidn., hydrogenation or hardening of fat, oil or fatty acid - Google Patents

Abstract

Treatment of spent catalysts (I), esp. metal, metal oxide or metal-metal-oxide catalysts, comprises crushing (I) mechanically to particles finer than 10 microns, using a mechanical energy with an energy density of 0.5-500, pref. 10-100 kW/l reactor vol. The metal component is converted to a deriv. before or during mechanical crushing, then the deriv. is converted to the metal (by redn., pref. with H2). The deriv. may be an oxide, hydride, carbide, nitride, nitrite, nitrate, carbonate, sulphate or halide. Crushing pref. is carried out in the presence of metal derivs. forming the metal or metal oxide of the catalyst, so that the reaction of the prod. regenerates (I). The spent (I) is crushed to particles finer than 4, pref. 0.1-4 microns, esp. with a narrow particle distribution with d50 = 0.1-1 micron. Crushing is carried out for 1 s to 60 min, pref. 5-15 min., with cooling, pref. in the presence of a fluid (oxidising or reducing fluid), esp. a liquid, pref. by milling. USE/ADVANTAGE - (I) are heterogeneous catalysts used in chemical processes, esp. oxidn., hydrogenation or hardening of fats, oils, fatty acids and/or their derivs. This regeneration treatment is very effective, simple and economical

Description

The present invention relates to a processing method used catalysts according to the generic term of Pa claim 1.

Heterogeneous catalysts based on metal catalysts, Metal oxide catalysts or metal-metal oxide catalysts are used in chemical processes, especially oxidation, hy Drying or hardening processes of fats, oils, fatty acids and / or their derivatives used. Such catalysts are for example in DE-OS 39 06 586, 37 06 658 and 39 42 064.

Due to the technical conditions when using the Kata lysators and in particular due to the he required there high temperatures or elevated pressures all show catalysis symptoms of deactivation after prolonged use, which has the consequence that the respective chemical reactions are not lead to the desired products or the yields of these  Reactions are reduced accordingly. Furthermore, can substrates are absorbed or absorbed from the catalysts, so for Example of the by-products formed in the reactions, the a deactivation of the catalyst or a surface effect the same. In any case, however because catalyst used after a certain operating time replaced or replaced with a new catalyst.

There is currently a regeneration of exchanged catalysts only technically possible and / or economical in a few cases sensible. Such regeneration requires users formation of enormous amounts of strong acids, bases or oxides tion or reducing agents, leading to significant Leads to environmental degradation. Insoluble catalysts, such as for example copper chromites, are mostly used as Son dumped as garbage digestion is economical are not responsible.

The present invention has for its object a Ver drive to work up used catalysts for Ver to provide, which is particularly simple and special can be carried out economically.

This task is accomplished by a procedure with the characteristics of Pa claim 1 solved.

The process according to the invention for working up used Catalysts, especially of used metal, metal oxide or metal-metal oxide catalysts, is based on the  Basic idea, the spent catalyst to a grain size smaller than 10 µ mechanically. In the mechanical Comminution is applied to the spent catalyst a mechanical energy, the energy density of this ener Power supply between 9.5 kW and 500 kW per liter of reactor volume, preferably between 10 kW and 100 kW per liter of reak goal volume, varies.

It was surprisingly found that one after the invent according to the process treated spent catalyst after Completion of the treatment returns to full catalyst activity owns. This is attributed to the fact that the mechani crushing the used catalyst to a grain size smaller than 10 µ then the catalyst particles present enter into a solid-state reaction with one another, which leads to that microcrystallites form, the crystallite size of Crystallite size of the original catalyst corresponds to and which are preferably on the order of 100 Angstroms and 300 angstroms, especially between 100 angstroms and 200 Angström. The crushing also causes that this leads to an enormous increase in surface area, so that the catalyst parts to be reacted with each other close contact. Because of that with simultaneous entry of the mechanical energy in the system will then make the activation energy available provides that is required to get from the used Ka talysator with the previously described regenerated catalyst to produce the crystallites mentioned there. In other words The method according to the invention thus allows regeneration  of the spent catalyst without being required is, the spent catalyst in appropriate solution means to dissolve or melt, as is the case according to the state the technology for the regeneration of only a few catalysts is known.

The method according to the invention has a number of advantages on. So it completely dispenses with the use of strong Ba sen, strong acids or other oxidizing agents, so that al This alone results in an enormous relief for the environment. Also the process according to the invention can be used with such a catalyst Use types that are not cleared according to the state of the art can be processed or for which according to the current status the technology is not economically viable is how this applies to the aforementioned and from the Known prior art copper chromite catalysts meets. Furthermore, the inventive method with a relatively low energy consumption feasible and also leads not to dust emissions. Furthermore, by using the inventive method valuable catalysts, such as for example, those containing precious metals can be easily processed work, so that the corresponding precious metal resources are conserved will. As a particular advantage of the method according to the invention it should be emphasized that the inventive method is characterized by a high level of economy, since it is single for this Lich is necessary, the spent catalyst among the to crush the aforementioned conditions.  

A first embodiment of the method according to the invention, the in particular for the preparation of metal-metal oxide catalyzes catalysts, such as those catalysts, in addition to Copper or nickel, cobalt and / or vanadium still correspond oxides of the aforementioned metals and further oxides contain titanium, chromium, silicon, aluminum and / or zinc, provides that the metal component of the used kata lysators derivatized and that one or simultaneously eats mechanical shredding. After that will then the derivatized metal component of the catalyst in the metal transferred, depending on the type of derivative such a transfer by oxidation and before preferably by reducing the corresponding metal derivatives tes is brought about.

A preferred embodiment of the embodiment described above tion variant of the method according to the invention provides that to derivatize the metal component of the catalyst oxidized before crushing, preferably to carry out tion of this oxidation the spent catalyst is heated and air or in particular oxygen is applied. To the mechanical size reduction of the catalyst energy density between 0.5 kW and 500 kW per liter of reactor volume, preferably with an energy density between 10 kW and 100 kW per liter of reactor volume, then the oxidized and in a grain size smaller than 10 µ of the present catalyst door components reduced so far that the desired metal me talloxide catalyst is present, the microcrystallites then before  preferably a size between 100 angstroms and 300 angstroms point.

Another embodiment of the method according to the invention stipulates that to work up the previously described Me tall metal oxide catalyst deri the metal component such vatized that from this the hydride, carbide, the nitride, the Nitrite, nitrate, carbonate, sulfate or a halide manufactures. After mechanical crushing to a A grain size smaller than 10 µ is then carried out accordingly Reduction of the metal component to the desired metal oxide.

Another, particularly advantageous embodiment of the inventions The method according to the invention provides that the workup of the performs used metal-metal oxide catalyst in such a way that the used catalyst in the presence of such Metal derivatives, their metals or metal oxides the catalyst form, crushed. After crushing, you then run one appropriate chemical reaction to that at the pulping in a solid state reaction to transfer regenerated metal-metal oxide catalyst. Here at the chemical reaction depends on which metal derivative was added to the spent catalyst. Before Appropriate metal oxides are also used as metal derivatives used, in which case the chemical reaction, which is carried out after the crushing, in a reduction consists.  

Above is in connection with the inventive method several times mentioned a reduction. Preferably this Re Production carried out with hydrogen, but also others Reducing agents, in particular also carbon monoxide, are suitable are.

A particularly suitable embodiment of the invention The method provides that the spent catalyst on a Grain size less than 4 microns, preferably to a grain size between between 0.1 µ and 4 µ, is crushed. This will secure represents that the inventive method with a high We Degree of efficiency with regard to the yield of regenerated catalyst expires.

A further increase in efficiency with regard to the yield of regenerated catalyst can be achieved by comminuting the used catalyst in such a way that it is present in a narrow grain size distribution with ad ₅₀ value between 0.1 μ and 1 μ. Here, the d ₅₀ value is defined such that at least 50% of the reactants are smaller than the stated d ₅₀ value, that is, for the case mentioned above, they are smaller than 0.1 μ to 1 μ.

The time required for the method according to the invention for the shredding depends on the regenerate the used catalyst. Usually this time varies between 1 second and 60 minutes, preferably between 5 minutes ten minutes.  

Of course, you can in the inventive method heat up the catalyst during comminution. However, this is in in many cases not necessary because of the size reduction and the De that may take place here and described above rivatization heat is released. However, to unwanted side-freak ions, caused by such an exothermic reaction, to prevent, is preferably the spent catalyst cooled during mechanical grinding.

To perform the heating or cooling described above ren, can be used to carry out the method according to the invention used reactor with appropriate heat exchangers det be.

A particularly suitable embodiment of the invention The process provides that the used catalyst its comminution applied with a fluid. Here can this fluid first for heat transfer, d. H. for heating or Cooling of the catalyst to be crushed can be used. In this case it is advisable to use an inert fluid as the fluid, for example an inert gas or preferably an inert gas Liquid.

On the other hand, it is desirable that the catalyst to be processed should be oxidized or reduced during comminution, so is in a further embodiment of the invention Process used an oxidizing or reducing fluid. With this fluid, which is a gas or preferably  mechanical comminution is a liquid the respective catalyst.

Regarding the procedure according to the invention rens required crushing of the used catalyst there are several options.

So looks a particularly suitable and economically successful che embodiment of the method according to the invention, that here the mechanical comminution by a corresponding mechanical grinding of the catalyst is brought about.

There is also the possibility of the required mechanical Crushing the catalyst and the associated energy Entry into the system by making a Performs ultrasound treatment.

Furthermore, he can in the method according to the invention achieve required comminution of the catalyst, that you accelerated at least two and opposed ge directed flows of catalyst particles collide lets so that the Ver driving energy required to overcome activation energy is provided as kinetic energy. The acceleration of the catalyst particles required for this can then, for example, via appropriate magnetic fields, elec tric fields or via suitable accelerated fluid flows, in which are fed in the catalyst particles will. In the latter case, a fluid is then preferably used  Gas or gas mixture selected, which then, if necessary, is either inert or has an oxidizing or reducing property owns.

The method according to the invention can be used in particular with sol Chen catalysts that, as already be be wrote, pure metal catalysts, metal-metal oxide catalyzes are catalysts or pure metal oxide catalysts. As examples this is what the metallic copper and silicon catalysts are or to name the metallic nickel-silicon catalysts, which are present in particular as an alloy and for hydrogenation or Hardening fats, oils, fatty acids and / or their derivatives be used.

In the oxidic catalysts, according to the invention Processes that can be regenerated are, in particular, the Hy Drier and hardening catalysts based on copper oxide or another metal oxide, preferably nickel oxide, cobalt oxide and / or vanadium oxide, in addition to the aforementioned oxides still titanium oxide, chromium oxide, silicon oxide, aluminum oxide and / or Contain zinc oxide. This can be particularly suitable However, the inventive method also for the regeneration of Copper-alumina catalysts or copper-oxide-titanium dioxide Use catalysts.

Advantageous further developments of the method according to the invention are specified in the subclaims.

The method according to the invention is described below using two Embodiments explained in more detail.

Embodiment 1

A copper oxide-chromium oxide catalyst of the general formula ( 2 Cu) × Cr ₂ O _{3 used} in industrial operation was first washed with methanol in a first processing step, in particular to remove organic compounds adhering to it.

The used copper oxide-chromium oxide catalyst was then oxidized in a first treatment stage with oxygen, so that a product resulted which can be represented by the formula (2 CuO) × Cr ₂ O ₃ .

The catalyst precursor thus oxidized was reduced to a grain size mechanically grind spectrum between 4 µ and 1 µ. Here be the grinding temperature was 50 ° C, the residence time when grinding 10 minutes and the energy density 15 kW per liter Reactor volume.

After grinding, a regenerated copper oxide-chromium oxide catalyst resulted, which had the chemical formula CuO × CuCr ₂ O ₄ on the basis of X-ray structure analyzes. The catalyst was then subjected to a customary hydrogen activation, so that the actually effective catalysts of the formula (2 Cu *) × Cr ₂ O ₃ or low oxidation states of the copper, in particular Cu ₂ O × Cr ₂ O ₃ , or mixtures of metallic Form copper and copper oxide.

This regenerated catalyst had 80 on its surface % By weight of microcrystallites whose crystallite size is between 100 Angstroms and 300 angstroms varied.

Comparative were regenerated with that previously described Copper oxide-chromium oxide catalyst and a new one Copper oxide-chromium oxide catalyst hydrogenations of lauric acid methyl ester performed. Here, the temperature was at Hydrogenation 300 ° C and the pressure in the hydrogenation 280 bar. The Residence times were 60 minutes in both cases.

The comparison of the hydrogenation showed that between the two Ka no differences in the hydrogenation yield and in the Hydrogen selectivity passed. In both cases the hy The yield is 90% lauryl alcohol (% by weight) and 1.5% of one is not by-product identified in more detail. The so made Lauryl alcohol was colorless in both cases.

Embodiment 2

A copper-titanium oxide catalyst of the general formula CuTiO ₃ consumed from industrial hydrogenation reactions was first oxidized by oxygen. Then the oxidized state of the catalyst was ground, the grinding time being 8 minutes and the energy density during grinding being 22 kW per liter of reactor volume. The grain size after grinding was between 8 µ and 4 µ.

The oxidic catalyst precursor described above was activated in a conventional manner with hydrogen, so that a catalyst of the general formula CuO × TiO ₂ resulted.

With this catalyst were compared to a new one Catalyst hydrogenation attempts of methyl laurate to Lau ryl alcohol performed. The temperature here was 250 ° C. the pressure 330 bar and the hydrogenation time 55 minutes.

In both cases the hydrogenation yield of lauryl alcohol was 90%. In addition to the lauryl alcohol, a single side pro could product (1.5%) can be detected, but this is not identi was infected. The hydrogenated lauryl alcohol was in both cases colorless.

Long-term trials have shown that the after Examples 1 and 2 regenerated catalysts in their service life does not differ from that of new catalytic converters were gates.

The new catalysts were produced by one process as in the patent application filed on the same day extension (attorney file 2021) by the same applicant.

Claims (14)

1. A process for working up used catalysts, in particular used metal, metal oxide or metal-metal oxide catalysts, characterized in that the spent catalyst is mechanically comminuted to a particle size of less than 10 μ me, the catalyst being comminuted Mechanical energy with an energy density between 0.5 kW and 500 kW per liter reactor volume, preferably an energy density between 10 kW and 100 kW per liter reactor volume. 2. The method according to claim 1 for the treatment of metal or Metal oxide catalysts, characterized in that the Metal component of the spent catalyst derivatized, that at the same time or afterwards the mechanical chopping and that the derivatized Me tall component of the catalyst converted into the metal.   3. The method according to claim 2, characterized in that one the metal component of the catalyst for derivatization oxidized after crushing and a reduction after crushing carries out. 4. The method according to claim 2, characterized in that one the corresponding for derivatization from the metal component Hydride, carbide, nitride, nitrite, nitrate, carbonate, sulfate or Halide produces and that one after the crushing Reduction. 5. The method according to any one of the preceding claims riding of used metal or metal-metal oxide catalyst catalysts, characterized in that the catalyst in Ge present of such metal derivatives, their metal or metal oxide form the catalyst, crushed and that you then ß implementation of the resulting product carries out the generated catalyst. 6. The method according to any one of claims 3 to 5, characterized records that one carries out the reduction with hydrogen. 7. The method according to any one of the preceding claims, characterized ge indicates that the spent catalyst on a Grain size less than 4 microns, preferably to a grain size between 0.1 µ and 4 µ, crushed. 8. The method according to claim 7, characterized in that the spent catalyst is comminuted such that it is present in a narrow grain size distribution with ad ₅₀ value between 0.1 µ and 1 µ. 9. The method according to any one of the preceding claims, characterized ge indicates that the catalyst is between 1 second and 60 Minutes, preferably between 5 minutes and 15 minutes, mecha niche crushed. 10. The method according to any one of the preceding claims, characterized characterized in that the catalyst during grinding tion cools. 11. The method according to any one of the preceding claims, characterized characterized in that the catalyst during comminution acted upon with a fluid. 12. The method according to claim 11, characterized in that one the catalyst with an oxidizing or reducing fluid acted upon. 13. The method according to claim 11 or 12, characterized in that that a liquid is used as the fluid. 14. The method according to any one of the preceding claims, characterized characterized in that the catalyst for mechanical Zer reduction grinded.