DE3029266C2 - Catalyst for the one-stage hydrogenation of heteroatom compounds and aromatic hydrocarbon mixtures - Google Patents

Description

The invention relates to a catalyst for the one-stage hydrogenation of hydrocarbon mixtures, especially for the perhydration of unrefined diesel fuel and vacuum distillate fractions.

For the hydrogenation of hydrocarbon fractions with the aim of largely removing Noble metal or nickel metal is used for unsaturated components and / or aromatic structures containing catalysts. As soon as the hydrocarbon fractions, however, sulfur and nitrogen compounds contain, deactivate these catalysts very quickly.

Therefore, for the hydrogenation of sulfur- and nitrogen-containing hydrocarbon fractions, preference is given to using Mo- and W-containing catalysts, which are usually promoted with Ni and sulfided with H ₂ S or organic sulfur compounds to increase the activity and stability. However, these types of catalyst, in particular those which are combined with a support such as Al ₂ O ₃ or aluminosilicate, do not have the hydrogenation strength or activity of the noble metal catalysts. As a result, some of the aromatics in the hydrocarbon fractions are not hydrogenated to naphthenes. The carrier-free types (e.g. NiO - WO ₃ ) are more effective in the hydrogenation of aromatic structures than those combined with Al ₂ O ₃ or aluminosilicate, but the low strength, which in operation after the absorption of the sulfur with the formation of the Metal sulfides of Ni and W are observed to be a critical deficiency. As a result of the swelling that occurs, the shaped catalyst piece becomes soft, partly destroyed and thus technically unusable (cf., for example, BAG Martynenko in Chim. Techn. Topliv masel 1975, 4, 19-22).

This deficiency has been circumvented earlier by using Ni-W sulfide catalysts. This has been abandoned, however, since difficulties arise when installing the catalyst in the reactor due to the _{release of H 2} S and the prevention of effectiveness due to the influence of O2 from the air. The activity stability of such types is

not very satisfactory (see e.g. Günther, G, Chem. Techn. 13 [196Ij, 427 and Münzing, E, Acta Chim. acad. scL hung. 36 [1963], 279-287). The pure WSr catalyst Although it is very active in hydrogenation and works in a stable manner, it also promotes the cleavage of C-C bonds and delivers hence undesirable by-products.

The aim of the invention is to propose an improved catalyst for single-stage hydrogenation purposes.

The technical task is to create a catalyst find which has the following properties:

a) insensitive to sulfur, oxygen and nitrogen compounds,

b) high hydrogenation performance (similar to noble metal catalysts) and low cleavage effect,

c) mechanically stable,

d) stable long-term behavior.

The technical problem is achieved by a catalyst for the one-stage hydrogenation of heteroatom compounds and aromatic hydrocarbon mixtures at hydrogen pressures of 5 to 30MPa, obtained by impregnating an X-ray amorphous aluminosilicate with an SiO ₂ content of 5 to 50 mass% and an Al ₂ O ₃ - Content of 50 to 95% by mass with a nickel and a tungsten compound and subsequent annealing at 673 to 873 ° K, the NiO content being 2 to 5% by mass and the W0 ₃ content being 15 to 30% by mass, solved by, according to the invention, the X-ray amorphous aluminosilicate thus obtained in powder form is intensively mixed with a second powdery component in a ratio of 4: 1 to 1: 4, which contains 30 to 70% by mass of NiO and 70 to 30% _{by mass of WO 3} , and by mixing of basic nickel carbonate and tungsten (VI) oxide, molding and subsequent annealing at 673 to 873 ° K, and that the mixture of the two components is then shaped.
The bulk catalyst density is advantageously 1.3 kg / l. In the single-stage hydrogenation treatment of unrefined hydrocarbon mixtures (such as diesel fuel and vacuum distillate fractions), the proposed catalyst shows a higher hydrogenation effect than that of the individual components, which was not to be expected. The hydrogenation performance can be compared with that of the noble metal catalysts. The presence of sulfur, oxygen and nitrogen compounds, which have a highly damaging influence on metal catalysts, has no disadvantageous consequences for the catalyst according to the invention. The high strength and the good activity time behavior are also advantageous.

The catalyst of the present invention

is particularly suitable for. extensive or complete hydrogenation (perhydration) of hydrocarbons, which contain unsaturated compounds and aromatics. At the same time, the catalyst is in capable of organic heteroatom compounds of sulfur, oxygen, nitrogen and certain heavy metal compounds (Nickel, iron, vanadium, copper in traces).

The general working parameters of the catalytic converter preferably include the following limit values:

H ₂ pressure

temperature

load

Gas: product ratio

5-30 MPa
473-723 ° K
0.2-2 v / vh
200-2000: 1 Nl / 1

During the treatment of unrefined raw materials

the catalyst absorbs up to 30% by mass of sulfur. In the case of NiO-WO ₃ catalysts, the uptake of sulfur in this amount normally has the consequence that the moldings lose their mechanical stability. Surprisingly, it has been found that the catalyst of the present invention has sufficient mechanical strength despite the uptake of large amounts of sulfur during the working period

In addition to good mechanical strength, the catalyst also has excellent activity-time behavior, so that it can also be used with advantage large-scale conditions can be used.

The hydrogenation products are particularly suitable as base oils for lubricants or as feedstock for technical cracks.

The catalyst is produced as follows:.

One component can be produced, for example, by mixing basic nickel carbonate and WoIfram (VI) oxide, both in powder form, preforming them on a tablet machine and calcining them at 673-873 ° K (NiO content: 30-70 mass -%, WO ₃ content: 30-70% by mass).

The other component is advantageously generated, by an X-ray amorphous aluminosilicate having a SiO ₂ content of 10-50% by mass of Ni (NO ₃ impregnated J ₂ and (NH ₄ J ₂ WO _4, and then annealed at 673-873 ⁰ K (NiO content: 2-5% by mass, WOr content: 15-30% by mass).

The two components are brought to a fineness of grinding <0.1 mm, mixed intensively with one another in a ratio of 4: 1 to 1: 4 and advantageously shaped into cylinder moldings The catalyst is heated up to approx. 673 ° K in an H ₂ S-free or low-H ₂ gas stream. This combination contradicts previous experience, according to which the best effectiveness of the S-insensitive Ni-W catalysts was achieved if the catalyst was previously sulphurized. Contrary to expectations, the catalyst according to the invention is more effective when it is used without sulfur.

45

example Production of component a)

Mixing 56.2 kg powdery NiCO ₃ and 65 kg powdery WO ₃ .

Subsequently Verpülung to 10 mm compacts and annealing at 450 ⁰ C remilling.

Production of component b)

Precipitation of an aluminosilicate with 20% SiO ₂ by continuously bringing together a solution of aluminum nitrate / water glass and an ammonia solution. The further work steps are aging, filtering, washing, drying, soaking with a solution of nickel nitrate and ammonium tungstate, evaporation of the excess liquid, drying and grinding. Components a) and b) are mixed in a mass ratio of 4: 1 (or 1: 4) and pelletized to give 5 mm pellets. The bulk density is 13 kg / 1.

The catalyst produced is used in the perhydrogenation of a diesel oil fraction. For comparison Catalysts were used in the same dimensions as those from component a) and the Component b), each alone, passed.

Diesel fuel parameters:

density

Boiling range

Base number

Sulfur content

Aromatics

at 293 ° K 0.830 493-623 ° C 33 mg NH _3/1 0.85% by mass of 25.0 vol .-%

The hydrogenation was carried out under the following conditions:

pressure

temperature

load

Gas: product ratio

19.0 MPa + 663 ° K l, 5v / vh 1000: 1 Nl / 1

Under these conditions were with the catalysts a) and b) and with the invention Catalyst determined the following residual aromatic contents:

Component a Component b Catalyst combination

2.8 vol% aromatics

10.5% by volume aromatics

0.5 vol% aromatics

After removal of the catalysts (after 600 hours), the catalyst of component a) only showed still low strength, which practically rules out industrial use, while the catalyst according to the invention showed no abrasion and possessed a technically useful strength.

Claims (1)

Claim: Catalyst for the one-stage hydrogenation of hydrocarbon mixtures containing heteroatom compounds and aromatics at hydrogen pressures of 5 to 30 MPa, obtained by impregnating an X-ray amorphous aluminosilicate with an SiO ₂ content of 5 to 50% by mass and an AJ ₂ O ₃ gel of 50 to 95 % By mass with a nickel and a tungsten compound and subsequent annealing at 673 to 873 ⁰ K, the NiO content being 2 to 5% by mass and the WO ₃ content being 15 to 30% by mass, characterized in that the so X-ray amorphous aluminosilicate obtained in powder form is intensively mixed with a second powdery component in a ratio of 4: 1 to 1: 4, which contains 30 to 70% by mass of NiO and 70 to 30% _{by mass of WO 3} and by mixing basic nickel carbonate and tungsten ( VI) oxide, molding and subsequent annealing at 673 to 873 ° K was produced, and that the mixture of the two components is then shaped.