CS261039B1 - Process for preparing nickel-molybdenum-alumina and cobalt-molybdenum-alumina catalysts - Google Patents

Abstract

A method for preparing catalysts for hydrocarbon processing based on nickel-molybdenum-alumina or cobalt-molybdenum-alumina by carbonization of a shaped, especially extruded support, in which the shaped gamma-alumina, either alone or containing compounds of fluorine, silicon and metals of group VI or VIII of the periodic system, which are introduced into the gamma-alumina before shaping, is saturated with an aqueous solution of molybdate and a salt of cobalt or nickel and orthophosphoric acid containing 200 to 400 g/1 M0O3, 40 to 90 g/1 NiO or CoO and 50 to 170 g/1 P2O5, optionally also 10 to 400 g/1 citric acid or hydrogen peroxide and having a pH of 1.0 to 7.0, after which the catalyst is dried and heat-treated. Before carbonization, the gamma-alumina may contain 0.5 to 5 wt. fluorine and 1 to 15% M0O3, which are introduced into the carrier by coprecipitation, or added to the precipitated suspension or to the alumina hydrogel before drying and shaping or during peptization and extrusion of the carrier. The catalyst achieves good physical properties and high activity in the processing of hydrocarbon fractions.

Description

The subject of the present invention is a method for preparing a hydrotreating catalyst of the Mo-Ni-alumina or Mo-Co-alumina type by carbonation of shaped gamma-alumina, either pure or containing active components or activators, suitable for hydrotreating, hydrogenation or isomerization.

Hydrotreating catalysts containing metals of Group VI of the Periodic Table such as molybdenum or tungsten and metals of Group VIII of the Periodic Table such as nickel or cobalt are used for the denitrogenation and desulfurization of various petroleum fractions.

A number of methods have been developed for the preparation of these catalysts, which consist in various combinations of the support, mainly alumina, with active components, such as co-precipitation, for example, of solutions of aluminum salts and soluble compounds of molybdenum Mo, tungsten W, nickel Ni and cobalt Co or in the addition of these compounds to the alumina hydrogel, or in the addition of catalytic components during peptization and molding to dried alumina, or finally in the impregnation of the heat-treated molded support with solutions of these catalytic components.

In the preparation of catalysts by carbonation of a shaped, e.g. extruded support, mainly alumina or aluminosilicate, aqueous solutions of soluble molybdenum or tungsten compounds and soluble nickel and cobalt compounds are used as impregnation solutions, and the process is carried out in one stage or in two stages, that is, the alumina is first saturated with e.g. ammonium heptamolybdate and then heat-treated and saturated with a solution of soluble cobalt or nickel compounds. Or the process is carried out in one stage by saturating the alumina with an ammoniacal complex solution of molybdenum and nickel or molybdenum and cobalt.

Alumina carbonation can also be carried out from a very dilute aqueous solution containing ammonium molybdate and nickel or cobalt nitrate on the principle of adsorption of these metals onto a carrier, using a large excess of the carbonating solution to the alumina, or increasing the adsorption rate by circulating the carbonating solution. It is also possible to work in such a way that the alumina carrier moves in the carbonating solution, or is firmly embedded in a solid layer through which the solution circulates intensively.

In all these impregnation processes, the stability of the solution, its concentration, pH and other parameters play a significant role, especially in contact with the alumina carrier.

In these catalyst preparation procedures, the texture of the support, its acidity, pore volume, specific surface area, etc. play a significant role.

However, it has now been found that nickel-molybdenum alumina and cobalt-molybdenum alumina can be prepared for the hydrorefining of petroleum fractions, or the isomerization of hydrocarbons or the hydrogenation of alkenes and aromatics by carbonizing a shaped, especially extruded carrier, in a method whose essence lies in the fact that the shaped gamma-alumina is calcined alone or containing compounds of fluorine, silicon and metals VI. or VIII. groups of the periodic system, which are introduced into gamma-alumina before shaping, are saturated with an aqueous solution of ammonium molybdate and a cobalt or nickel salt and orthophosphoric acid, containing 200 to 400 g/l MoO^, 40 to 90 g/l NiO or CoO and 50 to 170 g/l P_0_, optionally also 10 to 400 g/l citric acid or hydrogen peroxide and having a pH of 1.0 to 7.0, after which the catalyst is dried at 100 to 120 C after 1 to 5 hours of aging and calcined at a temperature of 200 to 600 °C.

The addition of orthophosphoric acid or citric acid or hydrogen peroxide converts the molybdenum ions into a complex form. Gamma-alumina before carbonation may contain 0.5 to 5 wt. % fluorine and 1 to 15 » MoO^, which are introduced into the carrier by coprecipitation, or added to the precipitated suspension or to the alumina hydrogel before drying and shaping or during peptization and extrusion of the carrier.

The invention therefore relates to the impregnation of alumina alone or activated with fluorine compounds or silicon or alumina coprecipitated with metals of group VI or VIII of the periodic table of elements with an aqueous solution of ammonium molybdate, converted into a complex compound, and a nickel or cobalt salt. The advantages of this process are that catalysts of higher activity can be obtained than by other processes, and the simplification of the production of these catalysts, since the saturation of the support with a sufficient amount of active components can be carried out in a single step.

In order to be able to work in one stage, that is without another stage of intermediate thermal treatment and repeated saturation, it is necessary that the starting alumina or coprecipitated carrier containing M0O3 or NiO or CoO and fluorine compounds has a suitable porosity and absorbency. It is preferable that the alumina has a bulk density of about 450 to 650 g/l and a absorbency of 55 to 75%, based on the annealed carrier. Another important factor is the heat treatment of the alumina used for impregnation at a temperature of 600 to 650 °C, which achieves an increase in the absorbency and porosity of the carrier.

For the saturation of alumina or alumina containing coprecipitated metals, aqueous solutions of ammonium molybdate and nickel or cobalt nitrate acidified with orthophosphoric acid are used. The amount of acid added is chosen so that sufficient stability of the solution and concentration, or pH of the saturation solution in the range of 1.0-7.0 are achieved.

However, for saturation, an aqueous solution of ammonium molybdate and nickel or cobalt nitrate acidified with citric acid can also be used, which converts molybdenum and nickel or cobalt compounds into complex compounds, and the solutions prepared in this way exhibit high stability.

As carriers, aluminas can be used alone, or activated with fluorine compounds containing 0.5 to 5% by weight, silicon compounds containing 0.1 to 1.5% SiC^. As carriers, aluminas of hydrogel from filter presses containing 20 to 25% A^O^ can also be used, which is whipped into a liquid paste in a homogenizer, to which ammonium molybdate is added and diluted with water to a content of 5 to 15% solids, and then dried in a spray dryer to a powdery mass, which is kneaded and extruded. However, ammonium molybdate can be added to the alumina kneader during peptization in an amount of 1 to 15 wt. %, whereby extrudates containing around 1 to 15% MoO^ after annealing at 450 to 550 °C are obtained by extrusion ^and these ^are then saturated with a solution of ammonium molybdate and nickel nitrate or only nickel nitrate Ni or cobalt nitrate Co. For the incorporation of catalytic components into the carrier, extruded thermally annealed aluminas or aluminas containing smaller amounts of coprecipitated metals such as MoO^ or NiO or CoO in the range of 0.1 to 15 wt. % and further 0.5 to 5 wt. % can also be used. fluorine, which was introduced into the carrier during precipitation by adding fluorine compounds such as AlF4, NH4F, H3SiF4 and the like directly to the suspension or in the form of NH4F or HF during peptization in preparation of the mass for extrusion.

The saturating solution is prepared, for example, by dissolving ammonium heptamolybdate with a content of approximately 80% M0O3, which is dissolved in hot condensate and a measured amount of orthophosphoric acid is added to the undissolved residue until everything is dissolved. Then powdered nickel or cobalt nitrate is added with stirring to completely dissolve everything. The saturating solution prepared in this way is not stored, but used immediately for saturating.

When preparing aqueous solutions of ammonium molybdate and nickel or cobalt nitrate, citric acid can be used, which is added to the solution in technical crystalline form, thereby increasing the solubility of these components due to the formation of complex compounds and increasing the stability of the solution.

In addition to the above molybdenum compounds, e.g. ammonium phosphomolybdate, ammonium dimolybdate, etc. can be used. As a second component, in addition to Ni or Co nitrate, nickel acetate, nickel citrate, nickel formate, nickel or cobalt chloride, etc. can be used. For example, nickel or cobalt carbonate can be used, which is converted into nickel or cobalt citrate by heating in an aqueous solution with citric acid, which is very advantageous for preparing a saturating solution.

The stability of the saturating solution depends on the amount of phosphoric or citric acid added. Too much of these acids in the solution is also not beneficial, as it causes

AND

261039 4 adversely affects the heat treatment of the saturated catalyst or reduces the activity of the produced catalysts.

It is necessary to choose the addition of acids to the saturating solution so that its pH is in the range of 0.5 to 7.0, preferably 1 to 4.5. As for extruded gamma-alumina, various types of alumina can be used, i.e. prepared, for example, by the aluminate process, alkoxide alumina, the so-called Ziegler alumina waste from the production of higher alcohols, chloride alumina prepared from wastewater, for example, from ethylbenzene, etc.

The actual carbonization of the alumina carrier can be carried out by various methods, such as spraying the carbonizing solution in a rotating drum using a small excess of the solution, filling the pores of the alumina with the carbonizing solution and leaving it to stand for a certain period of time, e.g. 1 to 2 hours, so that the catalytic substances are perfectly dispersed in the pores of the carrier.

Alumina can be saturated by immersion in a solution that is in excess of the carrier, whereby the saturation occurs by adsorption of metal substances from the solution, the amount of adsorbed components being increased by circulation of the solution through the firmly attached alumina carrier. During saturation, vacuum can be used to remove air from the pores and work under reduced pressure, etc.

For the saturation, both alumina and coprecipitated carriers containing MoO3 or NiO or CoO and saturation solutions of various concentrations can be used. When using the splash saturation method, solutions with a higher _MoO3 content in the range of 10 to 30 wt. % and NiO or CoO in the range of 1 to 10 wt. % are used.

However, it is also possible to work with very low concentration saturating solutions of around 2 to 9% MoO^ and 1 to 10% NiO or CoO, while the degree of adsorption can be increased by increasing the ratio of the saturating solution to alumina or to the precipitated carrier in the range of approximately 4 to 10:1, or by treating the saturating solution with a larger addition of inorganic or organic acid such as HNO^, H^PO^, CH^COOH, citric acid, hydrogen peroxide, etc.

The pH of the solution can also be adjusted by adding, for example, NH^OII, NH^NO^ and acid so that the solution contains the optimal amount of ammonium ions.

The invention is further illustrated in the following examples.

Example

The catalyst was prepared by carbonization of thermally activated gamma-alumina at a temperature of 600 to 650 °C for about 8 h in the form of extrudates of about 2 mm diameter, prepared by precipitation of sodium aluminate with nitric acid with the addition of AlF^ to the precipitated suspension. After washing with alkali condensate on filter presses and drying, dried alumina was obtained, which, after grinding in a jet mill to a fine powder containing about 75% below 0.06 mm, was /eptized in a kneader with water and acetic acid and extruded into noodles, which after heat treatment gave gamma-alumina spec.

with a surface area of 220 m/g.

The preparation of the saturating solution consisted of dissolving 30 g of ammonium heptamolybdate (NH^)6 Mo.y024 . 4 HjO in 50 ml of hot condensate with intensive stirring, after which 7 ml of H^PO^ ^approx . 85% was added to the undissolved residue until everything was dissolved. This produced about 63 ml of solution, to which 25 g of nickel nitrate in the form of crystalline wet: powder Ni(NO ₃ >2 · 6 I^O was added. The total amount of solution was about 75 ml and the pH of the solution was 1.5. The solution thus prepared was immediately used for saturating.

A saturating solution was added to 100 g of gamma-alumina extrudates with a bulk density of approximately 520 g/l while the mixture was in motion using a spray device. The actual saturating process took about 30 min, after which the remainder of the saturating solution was separated by dripping, but practically all of the solution was sucked into the pores of the alumina. The saturated catalyst was left to stand for about 1 to 2 h at laboratory temperature in a moist state so that the catalytic substances would be perfectly dispersed in the pores of the catalyst, and then it was dried at a temperature of

105 to 120 °C for about 24 h and then annealed at a temperature of up to 450 °C for about 7 h. The finished catalyst showed the following values:

extrudate d 1.8 mm, length 5-10 mm bulk density 680 g/1 spec. surface 153 m /g

Mo0 ₃ 17.9% by weight NiO 4.7% by weight Si°2 0.6% by weight On ₂ 0 0.09% by weight F 2.8% by weight P 2.1% by weight Loss on ignition at 600 °C 2.0% by weight

AljOj rest up to 100%

Example 2

The catalyst was prepared from a coprecipitated mass containing 10% MoO^, which was peptized with the addition of acetic and hydrofluoric acids and formed by extrusion into noodles, which after heat treatment at 450 to 600 °C had a bulk density of 590 g/l.

100 g of the thus prepared extrudates were saturated with 65 ml of a solution prepared by dissolving 25 g of ammonium molybdate in 40 ml of condensate and 5 ml of H2PO4 85% until everything was dissolved, then 25 g of nickel nitrate was added.

The thus prepared saturating solution was used to saturate the support containing about 10 wt. % MoO^ and 2 wt. % F for about 1 h. The saturated catalyst was left to stand for about 1 h at laboratory temperature and then dried at 105 to 120 °C and then annealed at 450 °C.

The finished catalyst contained 23.5% MoO2, 4.20% NiO, 2% F, 2.0% Pa and had a bulk density of 750 g/l.

Example3

The catalyst was prepared by carbonizing extruded alumina brand Condea with a bulk density of 570 g/l with a solution prepared by dissolving 35 g of ammonium molybdate in 45 ml of condensate and 10 g of citric acid. To this solution was added a solution of nickel(II) oirate prepared by dissolving nickel(II) carbonate in citric acid. The total amount of the carbonizing solution was 75 ml and had a pH = 1.0.

100 g of extruded alumina brand Condea was saturated with this solution for about 1 h, after draining the remaining solution after saturation, the catalyst was dried at 120 °C and annealed at 450 °C. The finished catalyst had the following values:

bulk weight

Mo0 ₃

NiO SiO ₂

At ₂ O lost antlers.

710 g/l 18.4% wt.

4.2% by weight 0.02% by weight 0.01% by weight 3.1% by weight

Example 4

The Co-Mo-alumina catalyst was prepared from extruded aluminate alumina with a content of 1.0% F, bulk density of 520 g/l. The saturating solution was prepared by dissolving 23 g of ammonium molybdate in 50 ml of water, to which 5 ml of 85% H ₃ PO ₄ was added. After complete dissolution, 20 g of cobalt nitrate was added. The total saturating solution was 75 ml.

100 g of extruded gamma-alumina thermally annealed at a temperature of 450 to 650 °C, spec. surface 2

220 m/g was saturated with this solution for about 1 h. The saturated catalyst was left to stand for about 1 h, then dried at 120 °C and annealed at 500 °C. The finished catalyst had the following values:

extrudate 0 1.5mm bulk weight 650g/1 special surface 170 ^m2 /g Mo0 ₃ 13.5% by weight CoO 3.5% by weight SiO ₂ 0.5% by weight

Na ₃ O 0.02 wt. %

F 1.0% wt.

P 1.8% wt.

loss of hardness at 600 °C 3.1 wt. %

Example 5

The catalyst was prepared from alumina-filter cake hydrogels containing 25% Al ₂ O ₃ , which was beaten into a liquid paste in a homogenizer, to which ammonium molybdate dissolved in water was added and diluted with water to a content of approximately 8% solids and dried in a spray dryer.

The powdered dried mass containing 15 wt.% Mo0 ₃ and 2% F was peptized with acetic acid in a kneader and extruded into noodles with a diameter of about 1.5 mm and heat-treated in a drying oven at 120 °C and annealed at 450 to 600 °C.

The thus prepared extrudates containing 15% MoO and 2% F were saturated with a solution of cobalt nitrate, ammonium molybdate and citric acid.

100 g of extrudates were saturated with a solution prepared by dissolving 25 g of cobalt nitrate hexahydrate in 50 ml of condensate and 1 g of ammonium molybdenum and 1 g of citric acid. The total amount of the saturating solution was 60 ml. The saturating time was 1 h, then left to stand for about 1 h, dried at 120 °C and annealed at 450 to 550 °C.

The finished catalyst had the following values:

extrudate 0 1.5mm bulk weight 750g/1 special surface 185 ^m2 /g moo ₃ 14.% by weight CoO 3.5% by weight SiO ₂ 0.7% by weight At ₂ ° 0.03% by weight F 1.5% by weight loss on ignition at 600 °C 2.5% by weight

The catalysts mentioned are suitable for hydrorefining various petroleum fractions containing organonitrogen and organosulfur compounds, as well as for hydrogenation of aromatic hydrocarbons, hydrogenation of alkenes, and also exhibit isomerization properties.

Example 6

The catalyst was prepared from gamma-alumina, which was obtained by precipitating the aluminum chloride solution from the production of ethylbenzene with ammonium carbonate, and the resulting aluminum hydroxide was filtered off, washed, dried, peptized and extruded, after which the obtained extrudates were calcined at 650 °C. 100 g of this support was immersed in a solution obtained by dissolving 24 g of ammonium heptamolybdate in 65 ml of deionized water, to which was added 3.3 ml of 85% Η^ΡΟ^ and subsequently adding 15 ml of a nickel nitrate solution containing 13.45 g of nickel nitrate hexahydrate. After half an hour of stirring in a rotating vessel, all the liquid was absorbed. The impregnated extrudates were dried at 120 °C and calcined in a stream of air

550 °C for 2 hours. The resulting catalyst showed the following values: extrudate, 0 mra, length 4-12 mm NiO 3.0 wt.% bulk weight 660g/1 _P2O5 2.7% _by weight. specific surface 182 ^m2 /g A1 ₂ Tiller remainder to 100% Mo0 ₃ 15.4% by weight In case the addition of orthophosphoric acid was only 1.7 ml, it was excluded from the saturating

solution after 18 h a small amount of precipitate formed. This phenomenon was prevented by the addition of 1.5 ml of 40% hydrogen peroxide. The resulting catalyst then had the following composition:

Mo0 ₃ NiO 15.5% by weight 3.0% by weight ^S 2°5 1.4% by weight Al 2^3 remaining up to 100%

SUBJECT OF THE INVENTION

Claims (2)

SUBJECT OF THE INVENTION Process for the preparation of nickel-molybdenum-alumina and cobalt-molybdenum-alumina catalysts for hydrotreating petroleum fractions, optionally for isomerization of hydrocarbons or hydrogenation of alkenes and romates by saturating a shaped, in particular extruded support, characterized in that the shaped gamma-alumina is either alone or containing fluorine compounds , silicon and metals VI. or VIII. groups of the periodic system which are introduced into the gamma-alumina prior to shaping are saturated with an aqueous solution of ammonium molybdate and a cobalt or nickel salt and orthophosphoric acid containing 200 to 400 g / l MOO3, 40 to 90 g / l NiO or CoO and 50 to 170 g / 1 P ₂ Og or P ° ^{and <IE} for 10- 400 g / l of citric acid or hydrogen peroxide and having a pH of 1.0 to 7.0, after which the catalyst is dried at 100 to 120 ° C for 1 to 5 hours and calcined at 200 to 600 ° C. 2. A process according to claim 1 wherein the gamma-alumina comprises 0.5 to 5 wt. fluorine and 1 to 15% MoO 2, which are incorporated into the carrier by co-precipitation, optionally added to the precipitated suspension or to the hydrogel of alumina prior to drying and molding, or during peptization and extrusion of the carrier.