WO2006082019A1

WO2006082019A1 - Desulfurization catalyst

Info

Publication number: WO2006082019A1
Application number: PCT/EP2006/000817
Authority: WO
Inventors: Friedrich Schmidt; Franz Grossmann; Richard Fischer; Michael Rau
Original assignee: Süd-Chemie AG
Priority date: 2005-01-31
Filing date: 2006-01-31
Publication date: 2006-08-10
Also published as: DE102005004368A1

Abstract

The invention relates to a desulfurization catalyst comprising a hydrogenation component for hydrogenating organic sulfurous compounds and an absorber component for absorbing hydrogen sulfide. The invention also relates to the use of said desulfurization catalyst for the desulfurization of hydrocarbon flows, especially methane flows. A suitable hydrogenation constituent is formed from copper and molybdenum, and a suitable absorber constituent is zinc oxide.

Description

Patent application

desulfurization

description

The invention relates to a desulfurization catalyst, as used for the desulfurization of hydrocarbon streams.

Most catalysts, especially those containing transition metals, are poisoned by organic sulfur compounds, thereby losing their activity. In many hydrocarbon conversion processes, such as the reforming of methane or other hydrocarbons, for example, in the production of synthesis gas for methanol synthesis or for power generation from methanol or other hydrocarbons in fuel cells, it is necessary to reduce the sulfur content in the hydrocarbon stream to the ppb range lower.

The separation of the organic sulfur compounds from the Hydrocarbon stream generally comprises two steps carried out in two separate reactors. In a first reactor, the organic sulfur compounds are reduced to hydrogen sulfide. For this purpose, the hydrocarbon stream is passed with the addition of a suitable reducing agent, such as gaseous hydrogen, for example, over a catalyst which typically contains cobalt and molybdenum or nickel and molybdenum. In the gas contained sulfur compounds such. B. Thiophenes are thereby reduced to produce hydrogen sulfide.

After the reduction, the gas stream is fed to a second reactor, in which the hydrogen sulfide originally contained in the gas or formed in the reduction of organic sulfur compounds is absorbed at a suitable absorber. Usually, the hydrocarbon stream passes through the bed of a solid absorber, for example a zinc oxide absorbent bed.

EP 1 192 981 A1 describes a process for preparing an agent for desulfurizing hydrocarbon streams, wherein a precipitate is precipitated from a mixture of a copper compound and a zinc compound such as nitrates with the aid of an aqueous solution of an alkaline compound such as sodium carbonate becomes . The precipitate is separated, washed, dried and calcined. ^■ The calcined product is processed into shaped bodies and the shaped bodies are then impregnated with a solution of an iron and / or nickel compound and the shaped bodies are then calcined again. The content of the calcined shaped bodies of iron and / or nickel is preferably 1 to 10 wt. -%.

No. 4,613,724 proposes a process for removing carbonyl sulfide (COS) from hydrocarbon streams, wherein the hydrocarbon stream is passed over an absorber containing zinc oxide and a promoter selected from the group of alumina, aluminum silicates and mixtures thereof. In addition, calcium oxide may also be contained as a promoter. The proportion of the promoter on the absorber material is preferably at most 15 wt. -%. The specific surface area of the absorber material is preferably 20 to 100 m ² / g. The particle size of the absorber material is preferably less than 2 mm, and more preferably between 0.5 and 1.5 mm. Preferably, the absorber material contains 85 to 95 wt. -% zinc oxide, 3 to 10 wt. -% alumina or Aluminum silicates and 0 to 5 wt. -% calcium oxide.

In US 5,348,928 a catalyst for the desulfurization of hydrocarbon streams is described, which as the hydrogenating component 4 to 10 wt. -% of a molybdenum compound, calculated as molybdenum oxide and 0, 5 to 3 wt. % of a cobalt compound calculated as cobalt oxide. Further, the catalyst comprises a carrier component which contains 0, 5 to 50 wt. -% of a magnesium compound and 0, 3 to 10 wt. % of a sodium compound, each calculated as an oxide. The specific surface area of the catalyst is not less than 268 m ² / g and the average pore diameter is not more than 300 Å. The catalyst can be prepared by, for example, impregnating the support with aqueous solutions of the salts of the active metal components.

In US 5,800,798 a method of producing fuel gas for fuel cells is described wherein a hydrocarbon stream having a sulfur content of not more than 5 ppm is passed over an absorbent to remove the sulfur. The absorbent comprises a copper-nickel alloy which has a ratio of copper to Nickel between 80:20 and 20:80 and a support material selected from the group of Al ₂ O ₃ , ZnO and MgO. The total content of the absorbent to copper and nickel, calculated as metals, is between 40 and 70 wt. -%. To generate the fuel gas, the purified coal water stream can then be fed to steam reforming. The absorbent for sulfur has a specific surface area in the range of 10 to 400 m ² / g and a pore volume in the range of 0, 1 to 1, 5 ml / g. The adsorbent preferably contains copper in a proportion of 11 to 22% by weight, nickel in a proportion of 21 to 30% by weight, zinc oxide in a proportion of 46 to 50% by weight. -% and alumina in a proportion of 10 to 11 wt. %, the specific surface area being 95 to 98 m ² / g.

In US 5, 302, 470 a system for energy production is described, which comprises a fuel cell. The fuel gas is recovered from a hydrocarbon stream by steam reforming. For desulfurization, the hydrocarbon stream is passed over a catalyst containing copper and zinc which lowers the sulfur content to less than 5 ppb. The catalyst is prepared by coprecipitation of a copper compound and a zinc compound and, if necessary,. made of an aluminum compound.

In order to allow the greatest possible desulfurization of the hydrocarbon stream, the hydrogenation catalysts used in the desulfurization of hydrocarbon streams should have a high hydrogenation activity towards sulfur-containing organic compounds such as thiophenes. The sulfur absorber should on the one hand have a high affinity for sulfur, in order to allow a reduction in the sulfur content to the lowest possible level, and on the other hand, a high sulfur absorption capacity to long service lives to reach the absorber, d. H . the longest possible intervals until replacement with a new, fresh absorber. Furthermore, the hydrogenation catalyst should show as little as possible of its hydrogenation activity over its lifetime.

The degree of desulfurization in hydrodesulfurization depends on the sulfur content of the gas stream to be desulphurized, the temperature at which the process is operated, and the activity of the catalyst. Typical catalysts for hydrodesulfurization are prepared by impregnation of supports such as alumina, with molybdenum or tungsten, which are treated with promoters such as cobalt or nickel. Typical catalysts for the hydrodesulfurization are, for example, mixtures of cobalt and molybdenum on alumina, nickel on alumina, or mixtures of cobalt and molybdenum, which are promoted with nickel and supported on alumina.

The invention was based on the object to provide a desulfurization catalyst for the desulfurization of hydrocarbon streams, with which an inexpensive desulfurization of hydrocarbon streams is made possible, wherein the hydrogenation catalyst has a high activity for the reduction of organic sulfur compounds and the absorber high affinity for sulfur and should have a high absorption capacity, so that a reduction of the sulfur content in the hydrocarbon stream is made possible up to the ppb range.

This object is achieved with a desulfurization catalyst having the features of patent claim 1. Advantageous embodiments of the desulfurization catalyst according to the invention are the subject of the dependent claims. The desulfurization catalyst of the present invention comprises a hydrogenation component for hydrogenating organic sulfur-containing compounds and an absorber component for absorbing hydrogen sulfide.

The catalyst according to the invention can hydrogenate both sulfur-containing organic compounds and also absorb the hydrogen sulfide formed in the hydrogenation. In contrast to the catalysts known from the prior art, the catalyst according to the invention takes on both functions required for the hydrodesulfurization of hydrocarbon streams. Therefore, only one reactor is required for desulfurization of the hydrocarbon stream, which simplifies desulfurization and reduces the cost of the process.

Suitable hydrogenation components are all compounds or metals which can reduce the content of sulfur-containing organic compounds. Suitable examples are the transition metals of the eighth subgroup of the Periodic Table of the Elements. It can be used individual metal compounds, as well as mixtures of metal compounds. Possibly . the desulfurization catalyst according to the invention must be activated at the beginning of the desulfurization, for example by a reductive treatment with hydrogen.

Suitable absorber components are in themselves all compounds which can absorb sulfur, for example transition metal oxides. The compounds are preferably selected so that the reaction of sulfur uptake is on the side of the sulfur compounds, that is, the sulfur uptake under the conditions of hydrodesulfurization is essentially quasi irreversible. Particularly preferred are those absorber components which can only be converted back into an oxide under drastic conditions, for example by a roasting process. The hydrogenation component is preferably present in an amount of less than 20% by weight and the absorber component in a proportion of more than 60% by weight. % in the desulfurization catalyst. The proportion of the hydrogenation component is calculated on the basis of the corresponding oxides, wherein the calculation of the proportion of each of the most stable oxide is used. If no stable oxide exists from the corresponding compound, generally a transition metal compound, the calculation is based on the pure metal.

The proportion of the hydrogenation component is particularly preferably less than 8% by weight, particularly preferably less than 5% by weight, and / or the proportion of the absorber component is more than 80% by weight, preferably more than 90% by weight, particularly preferably more than 95 wt. %, calculated in each case on the basis of the oxides of the components and based on the weight of the desulfurization catalyst (calcined to constant weight at 600 ^° C.).

Particularly preferably, the absorber component is formed from zinc oxide. Zinc oxide is a low-cost substance. It has a high affinity for hydrogen sulphide, so that the sulfur content in a hydrocarbon stream to be desulphurised can be lowered to values of less than 5 ppm, in particular up to the ppb range. Zinc sulfide gives virtually no sulfur under the conditions of hydrodesulfurization and can only be converted back to the oxide under severe reaction conditions.

The hydrogenation component preferably contains at least one element from the group of copper, molybdenum, tungsten, iron, nickel and cobalt. The hydrogenation component can be formed by only one element of this group, for example molybdenum, or also comprise a plurality of elements of the group, for example cobalt and molybdenum or nickel and tungsten. The elements of the group are present in the desulfurization catalyst generally at least proportionally in the form of their oxides.

According to a further preferred embodiment, the desulfurization catalyst according to the invention contains a binder. Such a binder can be provided, for example, when the catalyst is provided in the form of extrudates to achieve the required lateral compressive strength. The desulfurization catalyst of the present invention may also be provided in the form of tablets. These generally do not require a binder in order to achieve a side pressure resistance required for use in a reactor. Tablet-like desulfurization catalysts in their oxidic form usually contain only small amounts of a lubricant, such as graphite, in addition to the hydrogenation component and the absorber component.

As such, any binder can be present in the desulfurization catalyst according to the invention, provided that it does not interfere with the desulfurization of hydrocarbon streams. Preferably, the binder is selected from alumina, such as pseudoboehmite, aluminum silicates and zirconia. A suitable aluminum silicate is, for example, pseudoboehmite. However, for example, cement is also suitable as a binder.

The proportion of the binder is preferably chosen so high that a sufficient strength of the catalyst body is achieved and, on the other hand, the fraction of the binder is as low as possible, since the binder does not contribute to the catalytic activity of the catalyst or acts as an absorber. The binder is preferably present in an amount of less than 18% by weight, preferably less than 15% by weight, particularly preferably less than 10% by weight. In order to achieve a sufficient strength of the catalyst bodies, in particular if these are produced in the form of extrudates, the proportion of binding agent is preferably more than 5% by weight, in each case based on the weight of the desulfurization catalyst according to the invention (calcined to constant weight at 600 ^° C.).

The hydrogenation component is particularly preferably formed from copper and molybdenum. It has been found that by using copper and molybdenum compounds, a very active desulfurization catalyst can be obtained which enables desulfurization of the hydrocarbon streams down to concentrations of less than 5 ppm.

The copper is preferably contained in an amount of 0.5 to 5% by weight, particularly preferably 1 to 2.5% by weight, calculated as copper oxide and based on the total weight of the desulfurization catalyst.

The molybdenum is preferably in a proportion of 0.5 to 5 wt. %, more preferably 3 to 4, 5 wt .-%, calculated as molybdenum oxide and based on the weight of the desulfurization catalyst.

The catalyst according to the invention in its embodiment with zinc oxide as absorber component and copper and molybdenum compounds as hydrogenation components has very good properties in the desulfurization of hydrocarbon streams. It allows the simultaneous reduction of sulfur-containing organic compounds and the absorption of the resulting hydrogen sulfide. The sulfur is bound by the zinc oxide in close proximity to the hydrogenation-active metal compounds. For the hydrogenation catalytic activity, the molybdenum must be present at least in proportions in the form of the sulfide. If the catalyst is operated for a long time in a hydrocarbon stream which is free of sulfur-containing organic compounds, the molybdenum compound depletes of sulfur and is thus deactivated. There However, in the desulfurization catalyst according to the invention, the sulfur remains bound by the zinc oxide, the sulfur is available, so that the catalyst is immediately active again when again hydrocarbon streams are passed, containing sulfur-containing organic compounds.

The catalyst according to the invention has a multiplicity of defects in the crystal lattice. The inventors believe that the stresses generated thereby in the crystal lattice during the absorption of the sulfur constantly create new fracture surfaces in the zinc oxide, which are then available for a further absorption of hydrogen sulphide. As a result, the desulfurization catalyst according to the invention on the one hand has a very high affinity for hydrogen sulfide and on the other hand a high absorption capacity for hydrogen sulfide, since the zinc oxide can be used to a very high proportion for the absorption of hydrogen sulfide. However, the invention should not be limited by this theory.

The high number of defects in the lattice of the zinc oxide manifests itself in a broadening of the X-ray reflection in the X-ray diffractogram. The most intense reflection of ZnO in the X-ray diffraction preferably has a half-width of at least 2Θ = 0.15 °, preferably at least 2Θ = 0, 3 °, in particular at least 2Θ = 0, 4 °, and very particularly preferably at least 2Θ = 0, 42 ° up. The half width is preferably less than 2Θ = 0, 8 °. A half-width is understood as the width of an X-ray reflex in 50% of the height of the reflex.

The catalyst according to the invention preferably has a high specific surface area, which leads to a high catalytic activity. The catalyst preferably has a specific surface area of more than 5 m ² / g, preferably more than 20 m ² / g, particularly preferably more than 50 m ² / g. The specific surface can be determined with a BET method. A suitable method for determining the specific surface area will be described below.

The catalyst preferably has a total pore volume, as measured by Hg intrusion, of at least 30 mmVg, preferably at least 80 mm ³ / g and more preferably at least 100 mmVg and preferably at most 500 mirVVg, preferably at most 250 mm ³ / g and more preferably of at most 210 mm ³ / g. The fraction of the pore volume of the catalyst, measured by Hg intrusion, in the range of 3.7 to 7 nm is preferably at least 3 mm ³ / g, preferably at least 15 mmVg, more preferably at least 30 mmVg and preferably at most 80 mm ³ / g , preferably at most 70 mm ³ / g and particularly preferably at most 60 mm ³ / g. In contrast, the fraction of large transport pores in the range from 7500 nm to 875 nm, measured by Hg intrusion, preferably has at least a volume of 0.1 mm ³ / g, preferably at least 1.0 mm ³ / g and particularly preferably at least 2, 0 mm ³ / g and at most ^" 10 mm ³ / g. The fraction of the medium transport pores in the range from 875 nm to 40 nm, measured by Hg intrusion, preferably has at least a volume of 2 mm ³ / g, preferably at least 10 mm ³ / g and more preferably at least 20 mm ³ / g and preferably at most 100 mm ³ / g, whereas the fraction of small transport pores is in the range from 40 nm to 7.5 nm, measured by Hg. Intrusion, preferably at least a volume of 80 mm ³ / g, preferably at least 100 mm ³ / g and more preferably at least 150 mm ³ / g and preferably at most 300 mπvVg on.

According to a further embodiment, the desulfurization catalyst according to the invention is constructed from approximately spherical particles, which preferably have a mean diameter D ₅₀ in the range of 0.5 to 50 μm, particularly preferably 1 to 10 μm. A narrow size distribution of the particles will be especially achieved when according to the preferred embodiment described above, the suspension of thermally decomposable copper compound, thermally decomposable molybdenum compound, and solid zinc compound before the thermal decomposition is finely ground and the suspension is dried after thermal decomposition by spray drying.

According to a preferred embodiment, the desulfurization catalyst according to the invention is free of alumina and / or magnesium oxide.

The desulfurization catalyst according to the invention can be prepared by conventional methods. For example, the hydrogenation components can be deposited on the absorber component. Subsequently, it is generally still calcined in order to convert the components of the catalyst into the form of their oxides. But there are also other methods conceivable. For example, the starting components can be kneaded with the addition of water, with compounds selected as starting components which can be converted into the corresponding oxides by calcination, that is, for example, the carbonates or nitrates of the metals contained in the catalyst.

Another object of the invention relates to the use of the above-described desulfurization catalyst for the desulfurization of hydrocarbon streams. The desulfurization is carried out in the usual manner by the hydrocarbon Ström is passed with the addition of a small amount of reducing agent, in particular hydrogen gas, over a bed of the catalyst.

The desulfurization is carried out under normal conditions. For example, the reaction may suitably be in a temperature range of 260 to 550 ^° C, a hydrogen partial pressure from 0, 3 to 4 barg and a LHSV (liquid hourly space velocity) in the range of 0, 1 to 20 are performed. The desulfurization catalyst can be in the form of shaped articles, for example tablets or extrudates, or else in the form of granules. The diameter of the shaped bodies or granules is preferably selected in the range of 3 to 10 mm.

The catalyst of the invention is particularly suitable for the desulfurization of hydrocarbon streams having a sulfur content of less than 500 ppm, more preferably less than 400 ppm. Such hydrocarbon streams are formed, for example, by natural gas or associated gas in the crude oil production.

The invention will be further elucidated with reference to examples and with reference to the accompanying figures. Showing:

Fig. FIG. 1: an electron micrograph of a spray-dried catalyst before shaping and calcining, and

2 shows a laser granulometric analysis of the particle size distribution.

Determination Methods:

The following methods were used to determine the physical parameters:

Surface area / pore volume:

The surface was coated according to DIN 66131 on a fully automatic nitrogen porosimeter from Micromeritics, type ASAP 2010, Right . The pore volume was determined using the BJH method (E, P. Barrett, L, G. Joyner, P, P. Haienda, J. Am., Chem. Soc. 73 (1951) 373). Pore volumes of certain pore size ranges are determined by summing up incremental pore volumes, which are obtained from the evaluation of the adsorption isotherm according to BJH. The total pore volume according to the BJH method refers to pores with a diameter of 1.7 to 300 nm.

Pore volume (mercury porosimetry)

The pore volume and the pore radius distribution was determined according to DIN 66133.

Loss on ignition:

The loss on ignition was determined according to DIN ISO 803/806.

Bulk density:

The bulk density was determined according to DIN ISO 903.

sulfur uptake

A known amount of the sample to be measured was weighed in a ceramic boat and the sample was then placed in a heatable tube through which a stream of hydrogen sulfide (100%) was passed. The sample was left at 350 ^° C. under the hydrogen sulfide stream for 6 hours. The sample was then removed from the tube and cooled to room temperature with exclusion of air and moisture. The sample was weighed again and the sulfur uptake calculated from the weight difference.

Example 1 :

To 528 g of an ammonium bicarbonate solution (8, 3% CO ₂ , 12, 4% NH ₃ ) and 427 g of a solution of Cu (NH ₃ ) ₄ CO ₃ (Cu content: 40 g) were added. the 2637 g ZnO and 158 g (NH ₄ ) OMo ₇ O ₂₄ x 4 H ₂ O was added and the mixture with stirring for 30 minutes from 25 to 50 ⁰ C heated. The mixture was subsequently stirred at 50 ^° C. for a further 60 minutes. To decompose the copper and molybdenum compounds, steam was then introduced into the mixture for 90 minutes, during which the temperature of the mixture increased from 50 ^° C. to 103 ^° C. The steam supply was then turned off, and the resulting suspension was cooled from 103 ⁰ C to 35 ⁰ C for 14 hours. The supernatant clear solution was decanted off. The decanted solution still contained 0, 06 Gew. -% NH ₃ and 0, 5 ppm copper. The remaining suspension was dried by spray drying in countercurrent. The inlet temperature of the heated air was 330 ⁰ C to 350 ⁰ C. The temperature at the outlet of the dryer was 110 ⁰ C to 120 ⁰ C. In the exhaust air of the dryer, only traces of ammonia and carbon dioxide could be detected. The resulting powder was mixed with 2% graphite as a lubricant and then formed into tablets on a tablet press. The tablets were subsequently calcined. For this purpose, the tablets were heated with a temperature gradient of 2 ° C / min to 380 ⁰ C and this temperature is then maintained for a further 2 hours.

The physical data of the obtained catalyst are summarized in Table 1.

Example 2:

Example 1 was repeated except that the suspension was kept at 50 ° C. for 240 minutes prior to thermal decomposition. Table 1: physical characterization of the catalysts from Examples 1 and 2

Determined on a calcined at 900 ⁰ C ² powder determined according to DIN EN 1094-5

The catalysts obtained in Examples 1 and 2 do not differ significantly in their physical properties. In Example 2, a lower pore volume was measured. This decrease is attributed to the longer aging time of the suspension, through which the specific surface area decreased. The cat lysator from Example 2 shows the higher absorption capacity for sulfur.

Example 3

Example 1 was repeated, but after decomposition, the obtained suspension was aged for one week at room temperature.

Example 4

Example 1 was repeated, but after decomposition, the obtained suspension was aged for 24 hours at room temperature.

Example 5

Example 1 was repeated, but before the decomposition, the mixture was ground with an annular gap mill (FRYMA MS-32, Fryma-Koruma GmbH, DE, 79395 Neuchâtel). The mixture had a solids content of 25%. The grinding chamber was filled with 2, 4 1 ZrÜ ₂ ~ balls. The grinding gap was 7 mm. The speed of the mill was 645 rpm. The mixture was pumped through the mill at a rate of 3 l / min. For grinding, the suspension was passed once through the annular gap mill. Before spray-drying, the suspension was aged for 24 hours at room temperature.

Example 6

Example 5 was repeated, but before the decomposition, the suspension was ground five times with an annular gap mill. For this purpose, the suspension was passed through the annular gap mill five times. After decomposition, the suspension was aged at room temperature for 72 hours.

The physical data of the catalysts prepared in Examples 3 to 6 are summarized in Table 2. Table 2: physical characterization of the catalysts from Examples 3 to 5

: Determined on a powder calcined at 600 ° C

Due to the longer aging time in Example 3, the specific surface area decreased from 47 to 34 m ² / g and the pore volume decreased from 210 to 170 mrrvVg. By grinding in Examples 5 and 6, the specific surface area increased significantly as compared to samples that were not ground. Furthermore, the pore volume increased in the range of 3, 7 to 7 nm.

Fig. 1 shows an electron micrograph of the catalyst obtained in Example 6, recognizing the approximately spherical shape of the particles.

In Fig. Figure 2 shows the particle size distribution of the catalyst obtained in Example 5. The D ₅₀ value is 2.36 μm.

Claims

claims

A desulfurization catalyst comprising a hydrogenation component for hydrogenating organic sulfur-containing compounds and an absorber component for absorbing hydrogen sulfide.

The desulfurization catalyst according to claim 1, wherein the hydrogenation component is contained in a proportion of less than 20% by weight and the absorber component in an amount of more than 60% by weight in the desulfurization catalyst.

3. desulfurization catalyst according to any one of the preceding claims, wherein the absorber component is formed from zinc oxide.

4. desulfurization catalyst according to any one of the preceding claims, wherein the hydrogenation component contains at least one element selected from the group consisting of copper, molybdenum, tungsten, iron, nickel and cobalt.

5. desulfurization catalyst according to any one of the preceding claims, wherein the desulfurization catalyst comprises a binder.

The desulfurization catalyst of claim 5, wherein the binder is selected from alumina, aluminum silicates and zirconia.

7. desulfurization catalyst according to claim 5 or 6, wherein the binder in a proportion of less than 18 wt. -% is included.

8. desulfurization catalyst according to any one of the preceding claims, wherein the hydrogenation component is formed of copper and molybdenum.

9. desulfurization catalyst according to claim 8, wherein the copper in a proportion of 0, 5 to 5 wt. -%, calculated as copper oxide and based on the total weight of the desulfurization catalyst is included.

10. Desulfurization catalyst according to claim 8 or 9, wherein the molybdenum in an amount of 0, 5 to 5 wt -.%, Calculated as molybdenum oxide and based on the weight of the desulfurization catalyst is included.

11. desulfurization catalyst according to any one of the preceding claims, wherein the most intense reflection of ZnO in the X-ray diffractogram has a half-width of at least 2Θ = 0, 15 °.

12. desulfurization catalyst according to any one of the preceding claims, wherein the catalyst has a specific surface area of more than 5 m ² / g, preferably more than 20 m ² / g, particularly preferably more than 50 m ² / g.

A desulfurization catalyst according to any one of the preceding claims wherein the desulfurization catalyst is free of alumina and / or magnesia.

14. Use of the catalyst according to any one of claims 1 to 13 for the desulfurization of hydrocarbon streams.

Use according to claim 14, wherein the hydrocarbon stream contains less than 500 ppm of sulfur-containing organic compounds.

16. Use according to claim 14 or 15, wherein the hydrocarbon stream is formed substantially from methane.