DE102009027408A1 - Regeneration of oligomerization catalysts - Google Patents

Abstract

The invention relates to a method for activating a nickel oxide-containing catalyst, wherein the catalyst is calcined in the presence of an oxygen-containing gas in a temperature range of 300 to 750 ° C. The invention is based on the object to reduce the catalyst costs of oligomerization and to avoid environmental pollution. It has been found that used, deactivated nickel-containing oligomerization catalysts can be regenerated with little effort when calcined in the presence of an oxygen-containing gas in the temperature range from 400 to 750 ° C. Thus, the activation according to the invention is a regeneration of the catalyst in the used state.

Description

The present invention relates to a process for activating a nickel oxide-containing catalyst in which the catalyst is calcined in the presence of an oxygen-containing gas in a temperature range of 300 to 750 ° C. Such a method is known US 5,254,783 ,

Nickel-containing solid catalysts are used for the oligomerization of C ₃ to C ₅ olefins, in particular for the oligomerization of linear butenes. In the oligomerization of linear butenes, the catalyst should bring about a high conversion rate, a high selectivity for the dimers and a low degree of branching of the products, in particular the dimers.

Corresponding catalysts have been known for more than 60 years. One of the first descriptions is US 2,581,228 , Based on zeolite X they are z. In DE 3914817 (Hüls AG) or DE 10 2005 060 376 (BASF). DE 199 57173 (BASF) describes catalysts with supports of Al ₂ O ₃ , which are activated by the addition of acidic sulfates, in particular sulfuric acid. The use of supports based on silica-alumina, the known mixed oxide of SiO 2 with defined admixtures of Al 2 O 3, has proved to be particularly advantageous. EP 0734766 (KOA) describes the activation in addition to alumina also of silica-alumina using sulfuric acid compounds In this amorphous material properties such as acidity, BET specific surface area and porosity can be adjusted particularly effectively by targeted control of the synthesis parameters, other additives and by the conditions of activating calcination , Such catalysts are used for example in DE 4339713 (BASF) having compositions of 10-70% NiO, 5-30% TiO ₂ or ZrO ₂ , 20-40% SiO ₂ , 0-20% Al ₂ O ₃ and 0.01 to 1% of an alkali metal oxide.

In EP 0606314 For example, a catalyst is used whose silica alumina even contains less than about 1.0 mole percent Al ₂ O ₃ (based on SiO ₂ ).

US 5,254,783 describes similar catalysts prepared by depositing a monolayer of NiO on silica with additions of aluminum, indium or gallium. For the first activation of this catalyst is calcined in the presence of an oxygen-containing gas in a temperature range of 500 to 700 ° C. After use as an oligomerization catalyst, regeneration into nitrogen takes place.

Alles however, these catalysts are resistant to temperatures of at least 350 ° C, but usually even up to 500 ° C or even up to 700 ° C and more. They will according to the descriptions usually by thermal treatment in air or nitrogen preactivated at least 300 ° C and are usually all suitable for the regeneration process disclosed herein.

While change the use of the catalysts in the reaction Over time, the catalyst properties, with a cause the deposition of organic compounds on the catalyst, another a change of the authoritative ones Structures of the catalyst surface can be. His activity is reduced itself and the turnover speed decreases. The catalyst is taking a used condition. An increase in sales to the initial value by increasing the temperature is limited, because in strongly aged catalysts often with increasing temperature the degree of branching of the products increases. For example, reduced in the oligomerization of linear butenes in the dimer fraction the ratio of linear octenes to branched octenes. Since products with low degrees of branching are desired, can after a certain period of operation a high quality Product economical due to decreasing space-time yield no longer be produced, so the used catalyst must be changed.

The Nickel-containing oligomerization catalysts are expensive. The Disposal of used catalysts also causes costs and pollutes the environment.

Of the Invention is the object of the catalyst costs of a Reduce oligomerization and avoid environmental pollution.

It has now been found that used, deactivated nickel containing Oligomerisierungskatalysatoren regenerated with little effort when they are in the presence of an oxygen-containing Gas in the temperature range of 300 to 750 ° C calcined become.

The object is therefore achieved by a method for activating a nickel oxide-containing Ka catalysts in which the catalyst is calcined in the presence of an oxygen-containing gas in a temperature range of 300 to 750 ° C, wherein the activation is a regeneration of the catalyst in the used state. This method is the subject of the invention.

A The basic idea of the invention is not only the catalyst to activate a single time in its manufacture, but one Activation again at a later date, if the catalyst with increasing consumption is no longer the desired Achievement achieves. In the activation according to the invention it is therefore a regeneration with the aim of the original one Restore properties of a spent catalyst.

A Regeneration within the meaning of the invention is understood as activation a catalyst, which occurs only when the to be activated Catalyst used at least once for the oligomerization of olefins was and is used as a result. After regeneration can the catalyst as fresh back into the oligomerization be guided. The regeneration can also be done several times.

at The nickel oxide is preferably heterogeneous, oxidic Nickel.

The inventive method has the following advantages on: The preparation of an active catalyst by regeneration a used catalyst causes lower costs than the Production of a fresh contact. The amount of spent catalyst, which needs to be disposed of decreases. This relieves the burden on the environment.

Of the deactivated catalyst is preferably before being removed from the oligomerization reactor flushed with nitrogen and optionally also with steam, to remove volatile organic compounds. In front The regeneration can be a fine grain fraction, created by the Handling (installation, removal, transport, abrasion during the Oligomerization), separated by sieving.

The Regeneration is done in usual technical ovens for bulk materials such as rotary kiln or Shaft furnaces carried out.

The Regeneration of the catalyst comprises several processes or steps, namely the removal of organic deposits, the Restore the active surface texture as well the restoration of suitable precursors oligomerization active Centers.

It it is expected that the catalyst in the used state deposits having organic substances. Activation is then to be carried out that the deposits are at least partially removed.

The Removal of the organic compounds deposited in the catalyst is preferably done by burning (oxidative). As oxidizing agent be oxygen-containing gas mixtures such as air or other nitrogen / oxygen mixtures used. As oxidation products arise carbon oxides and water.

Added This burn-off step is performed by a pre-activation, the first Line by annealing and above all cooling in a defined Gas atmosphere takes place. Under preactivation here becomes one Treatment of the catalyst, which results in when fed with olefin mixtures a stationary State of high activity is achieved much faster as without such treatment. The pre-activation is expediently carried out immediately following the burning of the last carbon compounds.

Prefers the catalyst becomes a nickel compound prior to preactivation impregnated solution and dried.

The Cooling of the calcined catalyst is preferably carried out in an oxygen-poor atmosphere, because too much oxygen a temporary reduction and reoxidation of the catalyst and thus influence the activity of a freshly regenerated Catalyst can have. The oxygen content of a sufficient oxygen-poor atmosphere is only 200 to 5000 ppmv (part per million volumetric).

The Process is particularly suitable for regeneration of catalysts having the following composition: 5 to 50% by mass of nickel, 5 to 30 Mass% of alumina and 30 to 80 mass% of silicon dioxide contains, wherein the sum of said shares does not exceed 100%.

When Catalysts which have proved to be particularly regenerable have proved to be X-ray amorphous aluminosilicate and 3 to 25 mass% alumina contain. X-ray amorphous is a substance whose range of distances below the coherence length of the X-radiation used lies.

burn:

The Oxidation (burnup of organic deposits) can be, for example in a rotary kiln or shaft furnace continuously or discontinuously be performed. Preferably, the oxidation takes place continuously in a rotary kiln. For this purpose, the granules of deactivated catalyst via a feeder, For example, a vibratory trough, typically about 10 m long rotary tube supplied whose walls on one Temperature of 400 to 600 ° C, in particular from 500 to 600 ° C are kept. The necessary combustion air is supplied via the pipe cross-section in countercurrent. At the same time lances in the moving bed injected additional combustion air to a fast To ensure burnup. Immediately after the entry of the Calcined good in the rotary tube start the volatile organic components to evaporate and be over a ignited by the furnace stroking pilot flame. The temperature within the bed is dipping with Thermocouples measured and by controlling the oven jacket temperature and the air addition to a maximum value of, for example, approx. 670 ° C limited. When entering the cooling zone of the rotary tube, after a residence time of about 15 minutes, has the Residual carbon content of the granules has a value of at most 1.0%, usually even less than 0.5%.

To this pretreatment, which is primarily the elimination of the inhibitory Deposits, the catalyst can in principle in the second Treatment level to be transferred, in which the Catalyst surface for a fast and thorough Activation is conditioned. A closer look, however, has revealed that a coarsening of the nickel oxide crystallites in the catalyst during this oxidation treatment even with very careful control of the oxidation process can not be completely avoided. These coarsened crystallites react extremely slowly in the subsequent activation, so that Over time, the performance of the regenerated catalyst decreases slightly.

It has therefore proved to be advantageous, previously even by a suitable Addition of a nickel compound, which ultimately increases during calcination highly dispersed nickel oxide decomposes, the concentration on precursors of active centers. In this way, even a catalyst can be prepared which the Starting material in activity and selectivity even better (nickel order described later).

Otherwise The material can be supplied to the pre-activation immediately after burning become.

Pre-activation:

The Pre-activation can be done in various technical apparatuses, such as For example, a shaft furnace or rotary kiln, continuously or discontinuously. Preferably Pre-activation takes place continuously in a shaft furnace. It is made for example in a shaft furnace through the countercurrent calcining gas passed through the bed becomes. The shaft furnace opens below, below the calcination gas inlet, in a strongly tapered cooling tube, the calcining gas opposes a high flow resistance and it so derives upward. From the cooling tube, the granules below deducted by a controllable vibrating trough. additionally The cooling tube is about 50 cm below the taper with another gas (barrier gas) acted upon at a pressure which is equal to or greater than the pressure of the calcining gas. In this way it is ensured that the cooling tube in Essentially with barrier gas is applied and no calcining gas emerges from the cooling tube at the bottom.

The preactivation is carried out, for example, with a residence time in the calcination section of the shaft furnace of about 5 to 60 hours, preferably 20 to 40 hours, a calcination gas flow of about 0.2 to 4 m ³ calcining gas per kg fed granules and hour and an inlet temperature of the calcination gas from 350 to 750 ° C, in particular 600 to 700 ° C made. In addition to this heat introduced via the gas, additional energy can be introduced by active heating of the walls of the shaft furnace. As the calcining gas, for example, air, nitrogen or a mixture of both can be used. In the last zone of calcination, however, it is important to set a very defined atmosphere of the gas and to cool the catalyst therein.

This can be done very easily in the preferred arrangement of a shaft furnace with downstream cooling and discharge pipe. The calcine occurs, for example, in a cooling tube, where it has a Length of a few meters in about one hour to temperatures below 80 ° C is cooled down. It has proved extremely advantageous to keep the oxygen content of the cooling gas in this zone clearly very low, namely at 20 to 10,000, preferably 200-1000 ppmv. Under these conditions, it is believed that the cooling catalyst, more specifically the nickel oxide phase (NiO _x ), gives off minor amounts of oxygen. The practically black catalyst after oxidation becomes light green near x = 1 and then darker again. By means of the nickel oxide NiOx thus formed with a stoichiometric factor ≦ 1, the total system of the catalyst can be activated particularly easily for the oligomerization on exposure to olefins. If it takes several days before reaching about 90% of the stationary activity with black NiO (x> 1), the catalyst will reach this activity after a few hours after this treatment.

Of the so regenerated two-stage catalyst has an activity (defined as sales under standard conditions), which is 70% up 100% of that of a freshly prepared catalyst. In the oligomerization on a regenerated catalyst is the same product spectrum as in the oligomerization on one obtained freshly prepared catalyst.

Nickel job:

If it is desired, the used and to be regenerated Catalyst, as already mentioned, by additional Nickel deposition, which occurs in the sequence between burnup and pre-activation is worked up to a catalyst at the same permanent selectivity even higher activity as a freshly prepared catalyst. This can be, for example then be meaningful if the activity of merely using Burning and preactivation regenerated catalyst too low should be (for example, less than 90% of a freshly prepared Catalyst). Of course, an already can preactivated catalyst, for example, should be its performance unexpectedly prove unsatisfactory, also the Nachimprägnierung be subjected to nickel. It goes without saying that He then again a calcination and a renewed pre-activation must be subjected.

• a) oxidative Entfernung von organischen Ablagerungen vom gebrauchten Katalysator (Abbrand wie beschrieben);
• b) Inkontaktbringen der im Schritt a) erhaltenen Katalysatorvorstufe mit mindestens einer Nickelverbindung enthaltenen Lösung (Nickelauftrag);
• c) Trocknen;
• d) Kalzinieren und Voraktivieren der durch Nickelauftrag und Trocknung erhaltenen Masse wie beschrieben.

The optimal regeneration of a used catalyst comprises the following steps:

• a) oxidative removal of organic deposits from spent catalyst (burnup as described);
• b) bringing the catalyst precursor obtained in step a) into contact with at least one nickel compound (nickel coating);
• c) drying;
• d) calcining and preactivation of the composition obtained by nickel deposition and drying as described.

Of the Nickel application can be analogous to the production of fresh catalysts done, but with the difference that a smaller amount is applied to nickel compounds based on the solid. It depends on it, so nickel from a soluble Phase, that an extra amount of nickel oxide with a particularly large surface on the Catalyst is deposited. In principle, every soluble one can do this Nickel compound such as nickel nitrate, nickel acetate or nickel acetylacetonate used become. However, the use has proven to be particularly advantageous of those compounds which under the conditions of impregnation, Drying and calcining particularly poorly soluble and finely crystalline Precipitations result. That's why everyone appears those salts of nickel less suitable when drying Salt hydrates may result in their own Melt water of crystallization, such as. B. nickel nitrate. That way relatively large salt crystals form relatively when calcined large NiO crystallites with relatively low specificity Surface off.

When The use of nickelammine carbonate solutions has proven particularly advantageous proved simply by dissolving finely divided Nickel carbonate or nickel hydroxide carbonate in concentrated ammonia solutions are available with the addition of ammonium carbonate. such Solutions are with nickel contents of 0.5 to 14 mass%, in particular from 0.5 to 5% by mass, especially from 0.5 to 1.5 mass% used for the impregnation.

For nickel deposition, the spent catalyst is impregnated with, for example, about 1 percent nickelammine carbonate solution until the pores are saturated. The impregnation can be carried out by a method familiar to the person skilled in the art, such as, for example, a vacuum impregnation or by spraying until the permanent appearance of a liquid film on the surface (incipient wetness). If the solution uptake about 1 g of solution per g of catalyst, one achieves the deposition of about 0.5% additional nickel in the form of a basic carbonate. This addition has in practice at ge has been found to be absolutely sufficient for optimized after-treatment, pre-activation and activation to increase the activity of the catalyst to at least 100% of the original value of the fresh catalyst.

Naturally In this way, the nickel content of the catalyst is replaced by regeneration to increase regeneration a little, so you do not get it endless can often regenerate. In practice, however, reach the fresh and the regenerated catalyst in the reactor latencies between one and more than 4 years. Considering that the catalyst comes to be regenerated at least 5 times in this way on a total useful life of a material batch of more than 10, possibly even more than 20 years. At a productivity of at least about 0.4 kg of product / kg of catalyst / hour becomes Catalyst throughout its life cycle per kg So produce at least 30,000 kg of products. In practice this will be Value even exceeded. The amortization of the Catalyst is therefore particularly good by this method.

To the impregnation, the catalyst in a suitable Apparatus, for example a belt dryer with air flow or also a conical dryer, at temperatures between 100 and 200 ° C, in particular between 150 and 200 ° C and normal pressure or also dried in vacuo. This is the largest part of the bound ammonia particularly effectively aborted, the one unfavorable effect on the formation of dispersity of the nickel oxide.

Of the so dried, post-impregnated catalyst can directly, without further treatment in the pre-activation already described be used.

to Regeneration according to the specified method are all catalysts, whose oxide structure is stable under the conditions mentioned. Not accordingly suitable are heterogenized organometallic complex catalysts, only limited suitable catalysts on - optionally hydrous - phyllosilicates.

For the regeneration are therefore most suitable catalysts described in the literature suitable, the z. B. be described in US 2581228 . DE 3914817 (Hüls AG), DE 10 2005 060 376 (BASF), DE 199 57173 (BASF), EP 0734766 (KOA) DE 4339713 (BASF) or EP 0606314 , With regard to the content of individual components, they are initially not subject to any restrictions with respect to the regeneration process.

Preferably be with the aid of the method according to the invention oxidic oligomerization catalysts regenerating 1 to 60% by mass, in particular 10 to 30% by mass of nickel, 3 to 88% by mass, in particular 10 to 30 mass% of alumina and 10 to 88 mass%, in particular 40 to 80% by mass of silicon dioxide.

All catalysts are particularly preferably regenerated, which consist of a X-ray amorphous aluminosilicate with formal 10 to 16 mass% Alumina can be produced.

Of the regenerated catalyst can be used for the oligomerization an olefin or olefin mixture for which the consumed Catalyst was used, or for the oligomerization another olefin or olefin mixture can be used.

The regenerated catalysts can be used for the oligomerization of C ₂ to C ₁₀ , preferably C ₃ to C _6, olefins or olefin mixtures which contain virtually no further unsaturated compounds and polyunsaturated compounds such as dienes or acetylene derivatives. Preferably, olefin mixtures are used which contain less than 5% by mass, in particular less than 1% by mass, of branched olefins, based on the olefin content.

Propylene is produced industrially by cracking naphtha and is a basic chemical that is readily available. C ₆ olefins are contained in light benzine fractions from refineries or crackers. Technical blends containing linear C ₄ olefins are refinery minced petroleum fractions, C ₄ fractions from FC or steam crackers, mixtures of Fischer-Tropsch syntheses, mixtures of dehydrogenation of butanes, mixtures formed by metathesis, or other engineering processes.

For example, for the oligomerization using a catalyst regenerated according to the invention, suitable mixtures of linear butenes can be obtained from the C4 fraction of a steam cracker. In the process, butadiene is removed in the first step. This is done either by extraction or extrak distillation of the butadiene or its selective hydrogenation. In both cases, a virtually butadiene-free C _{4 cut is} obtained, the raffinate I. In the second step isobutene is removed from the C ₄ stream, z. B. by preparation of methyl tert-butyl ether (MTBE) by reaction with methanol. Other possibilities are the conversion of the isobutene from the raffinate I with water to tert-butanol or the acid-catalyzed oligomerization of the isobutene to diisobutene. The now isobutene-free C _{4 cut} , the raffinate II, contains, as desired, the linear butenes and optionally butanes. Optionally, the 1-butene can be separated by distillation. Both fractions, but-1-ene or but-2-ene, can be, after suitable pretreatment, in particular the removal of the last traces of butadiene, alcohol and water, which can cause a strong inhibition of these catalyst systems using the inventively regenerated Catalyst are oligomerized.

A Another possibility of producing a suitable educt It is similar to raffinate I, raffinate II or similar composite hydrocarbon mixture in a reactive column to hydroisomerize. It can u. a. to get a mixture, from 2-butenes, small amounts of 1-butene and optionally n-butane and isobutane and isobutene.

The Oligomerization with the inventively regenerated Catalyst may be in different, batch or preferably continuous working reactors, commonly used in solid / liquid contact reactions be used to be performed. When using operated by continuously operating flow reactors you usually, but not exclusively, a fixed bed. If a fixed-bed flow reactor is used, the Flow liquid upwards or downwards. Mostly becomes a downward flow of the liquid prefers. Furthermore, it is possible, the reactor under Product return (loop method) or im to operate straight passage.

at The use of tubular reactors can reduce the ratio of Length to diameter of the catalyst bed be varied, either by the geometric dimensions of the reactor or by its degree of filling. For the same amount of contact and load (LHSV) can thus different Leerrohrgeschwindigkeiten be achieved. Reactors in which a part of the reaction mixture can be recycled, with empty tube speeds be operated from 1 to 50 m / h. In the reactors, in the straight Passage can be passed, the Leerrohrgeschwindigkeiten in the range of 0.4 to 30 m / h.

The Catalyst load (LHSV) is typical of the reactors net 0.8 to 8 kg fresh feed / kg catalyst / h; that achieved Turnover per round is then 30-60% on the n-butenes.

There with increasing conversion, the concentrations of n-butenes continue to increase decreases and an additional dilution through the formed products takes place, a preferred variant of the method is the reactors with recycling of the starting olefins to operate. In the process, of the reaction discharges first the oligomers separated and the remaining residues partially attributed to the feeds of the corresponding reactors or forwarded to the following reaction stages.

In the rule contains the used olefin stream namely still saturated hydrocarbons of the same boiling range, d. H. inert substances, so that with increasing olefin conversion always diluted feed streams available stand. It is advisable in this case, several stages of oligomerization in a row to switch, where each operated with reaction conditions may be adapted to the reduced olefin concentration.

The Oligomerization can also be carried out in several process stages become. The number of reaction stages is between 1 and 10, preferably between 1 and 4. Optionally, an intermediate separation and recycling the inert components of the reaction product and / or unreacted olefins. The inventive Oligomerization of the olefins is preferred up to a setting the content of oligomers in the reaction product between 5 and 50, preferably between 5 and 45, in particular between 5 and 35 mass% performed in each stage. That way you can for technical mixtures used before the first oligomerization stage contain about 20% inert ingredients, over 80% of the Eduktstrom existing olefins are oligomerized. A residual current with less than 25% content of olefins can not usually economically be used more and is z. B. as LPG or Light petrol reused.

Everyone These reactors can be essentially adiabatic, polytropic or essentially isothermal, d. h., with a rise in temperature below 10 ° C, operated.

The Temperatures at which the reactors are operated, lie between 20 and 200 ° C, preferably between 70 and 160 ° C, especially between 70 and 130 ° C, especially between 80 and 120 ° C. With increasing temperature is a higher Selectivity of the reaction to higher n-octene levels to observe, unless the catalysts are too high a concentration contained at acidic centers and thus at least partially like the known acidic oligomerization catalysts work.

The Reaction can be at a pressure equal to or above the vapor pressure the feed hydrocarbon mixture at the respective reaction temperature be performed, preferably at a pressure below 40 bar. In order to avoid evaporation problems in the reactors, should the pressure 2 to 4 bar higher than the vapor pressure of the reaction mixture be at the highest temperature in the reactor.

Of the Total turnover of olefins depends on the type and amount of used catalyst, the reaction conditions set and number of reaction stages. Because of economical reasons is about all stages of olefin sales in the range of 50 to 95%, preferably held between 80 and 90%. About that In addition, it makes sense to obtain a high space-time yield, Hydrocarbons not containing linear olefins 60, preferably not less than 80% use.

It is advantageous for increasing the selectivities the content of oligomers in the reaction product between 5 and 45 mass%, preferably between 5 and 35% by mass by separation of the reaction products (Oligomers and other high boilers) of unreacted olefins and inert components of the reaction product (eg aliphatic) adjust.

Of the Oligomerenanteil in the discharge of the respective reaction stage preferably in the range of 10 to 35% by mass. The limitation of Concentration of oligomers can be determined by choice of operating parameters, such as Temperature or residence time.

A Another possibility is to increase the concentration Euctolefin at the reactor inlet by addition of a diluent below 80% by mass, in particular below 60% by mass. It is useful used a diluent, which is present in the starting material is and after partial or practically complete implementation of Eduktolefins recovered from the reaction mixture becomes. A preferred embodiment of the method is therefore, the reactor exit mixture into a fraction containing the oligomers and a second containing the diluent (s), contains the aliphatics and optionally unreacted olefin, to separate. The diluent with the contained therein Olefin is partly in the same reactor or one before switched back and the other part and passed into a downstream reactor or worked up. With several successive reactors can also more as an oligomeric partition.

The separated oligomers (from one or more separation units) be in a further distillation into dimers, trimers and higher Oligomers separated.

The oligomers prepared using a regenerated catalyst according to the invention are used, inter alia, for the preparation of aldehydes, alcohols and carboxylic acids. For example, the dimer of linear butenes by hydroformylation gives a nonanal mixture. This provides either by oxidation the ensprechenden carboxylic acids or by hydrogenation a C ₉ -alcohol mixture. The C ₉ acid mixture can be used to prepare lubricants, esters, metal soaps or salts. The C ₉ -alcohol mixture is a precursor for the preparation of plasticizers, in particular nonyl phthalates. The corresponding trimer is a precursor for isotridecanol which is, inter alia, a precursor for surfactants.

The The following examples are intended to explain the invention further, but not limit its scope of application itself from the description and the claims.

Example 1: Preparation of a fresh oligomerization

600 g of a substantially X-ray amorphous aluminosilicate having formally 13% by mass of aluminum oxide and a BET surface area of 400 m ² / g were mixed with 530 g of nickel carbonate paste (content: 50.5% NiO), 650 g of a nickel hexammine carbonate solution (content: 14 , 9% NiO), 16 g of ethylene glycol and 390 g of water mixed in a kneader to a well-mixed, earth-moist mass. This was extruded into strands of 2 mm diameter and 3-10 mm length and dried. Subsequently, the material was calcined at 600 ° C for 2 hours in the air stream, then switched to nitrogen flow and cooled.

Example 2: Oligomerization of linear Butenes on a freshly prepared catalyst

600 ml of catalyst, prepared on an industrial scale analogous to Example 1, was filled in a tempered with water outside tubular reactor of 2 m in length and 2 cm in diameter. Subsequently, a mixture of 20% by mass of 1-butene, 60% by mass of 2-butenes and 20% by mass of n-butane was run at a flow rate of 1 kg / h at a tube jacket temperature of 80 ° C. The pressure was kept constant at 30 bar. After a time of 40 h, a state was reached in which the turnover did not change. The results are summarized in Table 1. For further analysis, the product fraction was separated from the n-butane-butene fraction by evaporation of the low boilers and injected into a hydrogenating gas chromatograph. The hydrogenated C ₈ fraction compositions are also summarized in Table 1.

Of the Catalyst under laboratory conditions was exactly identical to the Conditions in a parallel technical shell and tube reactor operated, with integral sales and integral activity were identical in both. After 1200 hours, the temperature was of the mantle increased to 90 ° C, after another 3400 Hours at 100 ° C. The catalyst was among those mentioned Conditions operated for 9300 hours. The results are in table 1 summarized.

Example 3: Inventive Regeneration of the catalyst by oxidation and preactivation

The Granules of used catalyst from the large-scale Reactor became typical via a vibratory trough supplied to about 10 m long rotary kiln, whose walls kept at a temperature of 565 ° C. The combustion air is supplied via the pipe cross-section in countercurrent. At the same time lances in the moving bed injected additional combustion air. The fleeting ones Organic components evaporated and were ignited by a pilot flame inflamed. The temperature within the bed was measured with immersive thermocouples and by control the furnace jacket temperature and the air addition to a maximum value limited by about 670 ° C. The granules had to one at most 0.4%.

Subsequently the catalyst was in a shaft furnace with a diameter of about 30 cm and a length of about 6 m with a mass flow preactivated at 15 kg / h at a gas inlet temperature of 650 ° C. In countercurrent, a flow of about 40 Nm3 / h of air as calcining gas passed through the bed. The shaft furnace flowed down into a highly tapered cooling tube, from the the granules are pulled down by a controllable vibrating trough has been. In addition, the cooling tube was as above described, about 50 cm below the rejuvenation with nitrogen with an oxygen content of about 200 ppmv as a barrier gas, so that no calcining gas escapes from the bottom of the cooling tube. The exiting catalyst had a bright olive green color and quickly dimmed in the air.

Of the thus regenerated catalyst was under the specified in Example 2 Conditions tested in the specified pilot reactor for about 1000 h. The results are shown in Table 1.

Example 4: Inventive Regeneration by oxidation, application of nickel compounds and preactivate

Of the used catalyst was burned as in Example 3, then by impregnation with a dilute nickelammine carbonate solution with about 0.5 wt .-% nickel (as oxide) nachbeschegt, at 170 ° C. dried in a belt dryer and then, as described in Example 3, Calcined in the shaft furnace and preactivated.

The thus regenerated catalyst was also tested under the conditions given in Example 2 in the specified pilot reactor for about 1000 h. The results are shown in Table 1. Table 1: Summary of the results of the oligomerization experiments example catalyst temperature WHSV sales Selectivities (hydrogenated dimer) selectivity ° C Kg feed / l cat / h dimethylhexane methylheptane n-octane C8 2 fresh catalyst 80 1.7 47% 21% 62.5% 16.5% 87% 2 fresh catalyst 90 1.7 51% 20% 63.0% 17.0% 85% 3 regenerated catalyst 80 1.7 43% 22% 61.5% 16.5% 86% 3 regenerated catalyst 90 1.7 48% 21% 62.5% 16.5% 85% 4 regenerated catalyst 80 1.7 54% 16% 65% 19% 84% 4 regenerated catalyst 90 1.7 56% 15% 65% 20% 83%

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 5254783 [0001, 0005]
• - US 2581228 [0003, 0043]
• - DE 3914817 [0003, 0043]
• - DE 102005060376 [0003, 0043]
• - DE 19957173 [0003, 0043]
• - EP 0734766 [0003, 0043]
• - DE 4339713 [0003, 0043]
• EP 0606314 [0004, 0043]

Claims (8)

A method for activating a nickel oxide-containing catalyst, wherein the catalyst is calcined in the presence of an oxygen-containing gas in a temperature range of 300 to 750 ° C, characterized in that the activation is a regeneration of the catalyst in the used state. Method according to claim 1, characterized in that that the activation of the catalyst is carried out after in the presence of the catalyst to be calcined olefins were oligomerized. Method according to claim 1 or 2, characterized that the catalyst in the used state deposits organic Has substances which by activation at least partially be removed. Method according to claim 3, characterized that the removal of the deposits takes place by burning, and that then carried out a pre-activation becomes. Method according to claim 4, characterized in that that the catalyst after burning of the deposits and pre-activation impregnated with a solution containing a nickel compound and dried. Method according to one of claims 1 to 5, characterized in that the catalyst after calcination is cooled, the cooling in an atmosphere takes place, the oxygen content is between 200 and 5000 ppmv. Method according to one of claims 1 to 6, characterized in that the catalyst 5 to 50% by mass Nickel, 5 to 30% by mass of alumina and 30 to 80% by mass Contains silicon dioxide, the sum of said proportions Does not exceed 100%. Method according to one of claims 1 to 7, characterized in that the catalyst X-ray amorphous Alumosilikat with 3 to 25% by mass of alumina content.