CZ253199A3 - Anti-hydration catalyst resistant to sulfur for conversion carbon monooxide with steam and process for preparing thereof - Google Patents

Abstract

The present invention relates to a sulfur resistant catalyst for conversion carbon monooxide with steam containing compounds of cobalt and molybdenum as active components, an alkali metal compound as a promoter, and a carrier. The carrier comprises one or several oxides being selected from the group consisting of TiOi2, Ali2Oi3, and/or MgO, rare earth oxides and/or ZnO, whereby the amount of TiOi2 is in the range of 30 percent by weight to 80 percent by weight, where the percentage is based on the carried total weight. There is also disclosed a process for preparing such catalyst, the process comprises several steps wherein in the first step a) there is mixed an aluminium compound and/or a magnesium compound with one or several compounds being selected from the group consisting of rare earth compounds and zinc compounds functioning as anti-hydration auxiliary compounds, then the resulting mixture is calcined and subsequently the disintegrated solid product is crushed; in the step b) the obtained mixture is mixed in dry state with a titanium compound, subsequently the resulting mixture is extruded to form elongate pieces that are then subjected to calcination in order to obtain a carrier. Subsequently, there is prepared a co-impregnation solution of molybdenum and cobalt compounds as active components of the catalyst and the alkali metal compound. This solution serves for impregnation of the carrier obtained in the step b), and then the impregnated carried is subjected to calcination and disintegration.

Description

Anti-hydration and sulfur-resistant catalyst for the conversion of carbon monoxide by steam and a process for its preparation

Technical field

The present invention relates to a novel sulfur-resistant carbon monoxide conversion catalyst and to a process for the preparation thereof, more particularly to an anti-hydration and sulfur-resistant carbon monoxide rearrangement catalyst and to a process for preparing the catalyst.

BACKGROUND OF THE INVENTION

The conversion of carbon monoxide by steam is known as an important method of producing hydrogen and synthesis gas. A sulfur-resistant catalyst should be used for the starting material having a high sulfur content. At present, sulfur-resistant catalysts which contain rare earth modified Y-Al 2 O 3 or Y-Al 2 O 3 as a carrier are widely used industrially. Chinese patent CN 1018049 discloses a catalyst comprising γ-ΑΙ ₂ Ο ₃ as carrier, Mo and Co as active ingredients and alkali metals as promoters; the catalyst is to be sulfurised at a relatively high temperature prior to use. U.S. Pat. No. 4,153,580 discloses that rare earth oxides have been added to the hydrated alumina and mixed, suitably shaped, and calcined to provide a carrier. The carrier obtained was impregnated with a suitable amount of decomposable cobalt and molybdenum compounds which, after impregnation, were converted to oxides to obtain a sulfur-resistant catalyst. Although it can be easily sulphurized at low temperature, it has little hydration stability, as does the catalyst disclosed in Chinese patent CN 1018049, which occurs when used at high partial pressure. 0 · 0 0000 000 000

0 0 0 0

00 00 0 «steam, to some extent, the hydration reaction, which leads to phase changes and deactivation of the catalyst to stabilize the structure of the catalysts are used in a high partial pressure of water vapor, is used in the carrier composition MgO.AI TiO ₂ O3.a ₂ and rare earth compounds as promoters, as suggested in Chinese patent CN 1096494, which better solved the problem of hydration. This catalyst is one of the sulfur-free alkali metal catalysts for the conversion of carbon monoxide, since alkali metal compounds are not used in its preparation. Unfortunately, the cost of producing this catalyst is relatively high because grinding and kneading is used. Chinese Patent No. 1154271 (Application No. 96100935.7) discloses a cost-effective method consisting of dry blending, kneading, calcination and impregnation. The main carrier components of this catalyst prepared according to this patent are MgO and Al ₂ O ₃ , with a small amount of TiO ₂ .

The catalyst prepared by this method was sufficiently strong, highly stable and readily regenerable, which may be due to the formation of a spinel structure during the calcination of MgO and ΑΙ ₂ θ3. The addition of alkali metal compounds in this production improves the efficiency of the catalyst at low temperature, but its hydration resistance, or anti-hydratability, is low.

Nowadays, when designing oil substitution by coal for nutrient preparation, large-scale plant fertilizer preparation and re-expansion of medium-sized productions, true coal is often chosen as the starting material and a three-stage 4.0 MPa unit is used, using a durable process against sulfur (serial connection of medium and low temperature conversion) followed by methanation purification. With low-temperature conversion technology, the catalyst must be operated at difficult temperatures. 9 9 9 9 • 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9

9 9 9 9 9

999 9 99 99 99 99 conditions of high water vapor partial pressure and at low temperature, which is usually in the range of 20 ° C from the dew point temperature. That is, the sulfur-resistant conversion catalyst should exhibit not only high activity at low temperature but also good hydration resistance and structural stability.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a catalyst which has good anti-hydratability, low temperature activity and structural stability and is not subject to hydration and phase changes when used under the reaction conditions outlined above.

The sulfur-resistant conversion catalyst of the invention comprises as active ingredients a cobalt and molybdenum compound, as a promoter an alkali metal compound, as a carrier skeleton material a porous aluminum compound and a porous magnesium compound or a combination thereof and one or more compounds selected from the group consisting of rare earth metal compounds, preferably nitrates of these metals, and as anti-hydrating adjuvants zinc compounds, preferably zinc oxide and zinc nitrate in combination with the titanium compound, the titanium compound content of the carrier preferably being adjusted to 30 wt% to 80 wt%. %, calculated as TiO ₂ . The sulfur-resistant CO conversion catalyst thus obtained has surprisingly good anti-hydratability, good low temperature activity and good structural stability.

The content of cobalt and molybdenum compounds as active catalyst components is: MOO3 .... 5 wt. % to 20 wt. % a

CoO ..... 0.5 wt. % to 5 wt.%, and the content of the alkali metal promoter is 0.1 wt. % to 20 wt. %

4 4 4 4 4 4 4 4 4 4 4 444

4 4 44 44 4 · 44 (calculated as oxides). The alkali metal may be potassium or sodium. For the selection of the percentage of active ingredients and the promoter which is the alkali metal compound, see Chinese patents CN 1018049, CN 1042482 and CN 1048989,

Said aluminum compounds used as skeletal materials in the invention may be aluminum hydroxide, pseudobromite, gypsum or alumina, preferably aluminum hydroxide or pseudobromite. The porous magnesium compounds of the invention may be magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium nitrate, with magnesium carbonate and magnesium oxide being preferred. A combination of any of these compounds may also be used as the scaffold material.

The zinc compounds may be zinc oxide or thermally decomposable zinc compounds such as zinc nitrate, zinc carbonate and the like, which may decompose upon heating to form zinc oxide. The anti-hydrating adjuvant used in the invention may be nitrates or lanthanum oxides, cerium nitrates or oxides, zinc nitrate and zinc oxide and the like, or mixtures of two or more of the above compounds, preferably lanthanum nitrate, lanthanum oxide or zinc nitrate.

If at least one rare earth compound is used as an anti-hydrating adjuvant, its content should be 0.01% by weight. % to 10 wt. %, based on the total weight of the carrier, and converted to oxides.

If a zinc compound is used as an anti-hydrating adjuvant, the zinc compound is preferably 0.10 wt. % • 4 • 4 · 4 4 4 · 4 · 4 · · · 4 4 4 4 4 · 4 4 «1 · 4 4444 · · · 444

4 4 4 4 4 4 _ up to 10 wt. % of the total weight of the calcined carrier and calculated as oxides.

The content of the titanium compound, calculated as titanium dioxide, is preferably in the range of 30 wt. % to 80 wt. % of the total weight of the calcined carrier.

The titanium compounds to be used according to the invention may be titanium dioxide, titanium hydroxide, metatitanium acid, titanium dioxide, rutile or anatase, or a mixture of any two or more thereof, preferably metatitanium acid.

The process for preparing the support for the catalyst of the invention is illustrated below. Said porous aluminum compounds and porous magnesium compounds are mixed with at least one anti-hydrating adjuvant selected from the group consisting of rare earth metal compounds, preferably nitrates and said zinc compounds, in particular zinc oxide and zinc nitrate, after which the resulting mixture is decomposed by calcination and crush; thereafter the regrind obtained is dry blended with the titanium compound and the resulting mixture extruded and calcined to obtain a catalyst support; By mixing the molybdenum and cobalt compounds as active ingredients and the alkali metal compound, a co-impregnation solution is prepared, and the obtained carrier is saturated with the prepared co-impregnation solution, then the impregnated carrier is calcined and decomposed to the anti-hydration and sulfur-resistant conversion catalyst of the invention.

When mixing the above mixture with the titanium compound, a peptizer may be added. The peptizer may be nitric acid, aqueous alkaline earth nitrate solution, aqueous flfl · ·

9 9 flflflfl flflflfl fl fl flll fll flll flll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll fll of these substances, in particular nitric acid or potassium nitrate solution. The peptizer may also be a solid peptizer, such as alkaline earth metal oxides, alkaline earth metal hydroxides or alkaline earth metal sulfides.

When the catalyst of the invention is used for sulfur-resistant water vapor conversion under severe conditions of 20 ° C below the dew point, there is no hydration or catalyst change, demonstrating high anti-hydratability and structural stability of the catalyst, but using a commercial catalyst for low temperature conversions, eg C25-20-02, QCS-02 and EB-m4 and the like under the same conditions, all are subject to phase changes (see Fig. 1 attached). Further, the process for preparing the catalyst of the invention is simple, since grinding and kneading is not performed, which greatly reduces production costs.

The following are illustrations and examples which are illustrative only and do not limit the scope of the invention.

Brief overview of the drawings

Giant. 1. is a diagram of phase changes before and after hydrothermal treatment of the CT-4 catalyst according to the invention, the meaning of the symbols being:

and .... prior to hydrothermal treatment; b .... after hydrothermal treatment.

• 9 · 9 · 9 · 999 999 ··· ♦ ··

9 9 9 · y _ ··· * ·· ·· · ♦ ··

Fig. 2 is a diagram of phase changes before and after hydrothermal treatment of several commercial and conventional catalysts, wherein:

and .... fresh commercial catalyst ED-4; b .... fresh commercial catalyst QCS-02; c .... fresh commercial catalyst C25-2-02; d .... commercial catalyst EB-4 after hydrothermal treatment;

e .... commercial catalyst QCS-02 after hydrothermal treatment;

f .... commercial catalyst C25-2-02 after hydrothermal treatment.

Fig. 3 shows the phase spectrum after hydrothermal treatment of a catalyst according to the invention, wherein:

and .... CT-1 after hydrothermal treatment; b .... CT-2 after hydrothermal treatment; c .... CT-3 after hydrothermal treatment; d .... CT-4 after hydrothermal treatment.

DETAILED DESCRIPTION OF THE INVENTION

Example 1; Catalyst Preparation (1) Carrier Preparation

Carrier Z-1

A solution of 10g of La2O3 was prepared, and this solution was mixed with 200g of Al (OH) 3 and 100g of MgCO3. The resulting mixture was calcined at 700 ° C for 2 hours and the calcined product was crushed. To this crushed product was then added 400g of metatitanium acid, then 10% nitric acid and the resulting mixture

Μ ··

- 7 - ···

00 ·· * 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0

00 ·· · · was kneaded and extruded. The extruded pieces were calcined at 500 ° C. The catalyst support thus obtained was designated as Z-1 support. Its composition is shown in Table 1.

Carrier Z-2

The preparation was the same as the preparation of the Z-1 carrier in the general steps except that the aqueous solution used contained 30g of zinc nitrate instead of La2O3. The catalyst support thus obtained was designated as Z-2 support. Its composition is shown in Table 1.

Carrier Z-3

The preparation was in the general steps the same as the preparation of the Z-1 support, except that 200g of metatitanic acid was used instead of 400g of metatitanic acid and the weight of MgCO 3 used was Og instead of 100g. The catalyst support thus obtained was designated as Z-3 support. Its composition is shown in Table 1.

Carrier Z-4

The preparation was in the general steps the same as the preparation of the Z-2 support, except that 200g of metatitanium acid was used instead of 400g of metatitanium acid. The catalyst support thus obtained was designated as Z-4 support. Its composition is shown in Table 1.

Carrier Z-5

The preparation in the general steps was the same as far Z-1 Carrier, except that 36g of La ₂ O3 was used instead of 10g of La ₂ O3, the weight of Al (OH) 3 used was Og instead of 200g and 400g metatitanium acid as As used in Z-1, 200 g of titanium hydroxide and 200 g of metatitanium acid were used. Carrier * and * 9 · 9 · 9 · · ·

9 · · ···· ♦ ···

And aaa and aaaa a and aaa and aa a * aa ·· of the catalyst thus obtained was designated as Z-5 support. Its composition is shown in Table 1.

Carrier Z-6

The preparation in the general steps was the same as the preparation of Z-2, except that the weight of zinc nitrate was 90g, instead of 100g of MgCO3, 100g of MgO was used, and the weight of the metatitanium acid used was 200g. The catalyst support thus obtained was designated as Z-6 Support. Its composition is shown in Table 1.

Carrier Z-7

The preparation was generally the same as the preparation of the Z-7 support, except that the weight of La ₂ O ₃ used was 0.05g. The catalyst support obtained was designated as Z-7 support. Its composition is shown in Table 1.

Carrier Z-8

The preparation was generally the same as the preparation of the Z-2 carrier, except that the weight of the zinc nitrate was 1g. The catalyst support obtained was designated as Z-8 Support. Its composition is shown in Table 1.

(2) Preparation of the catalyst

First, a co-impregnation was prepared from 55 g of ammonium molybdate, 5.0 g of cobalt nitrate and 50 g of potassium carbonate. 50 g aliquots of each test carrier obtained as described above were soaked with this solution. Thereafter, the impregnated supports were calcined and decomposed at 400 ° C to obtain catalysts which are designated as:

··· ♦

- 10 tet tet tet tet tet tet tet tet tet tet tet tet tet * tet tet tet * tet * * * * * * tet * * ·· ·· ··

CT-1, CT-2, CT-3, CT-4, CT-5, CT-6, CT-7 and CT-8, which corresponds to the designations used hereinafter in the description and in the table.

Example 2 Catalyst efficiency test

In a pressurized standard apparatus, filled sequentially with the original catalyst grains, the catalysts of the invention and commercial catalysts, the mixture of hydrogen and steam was hydrothermally treated at a temperature of 18 to 20 ° C from the dew point (i.e., pressure: 4). MPa, temperature: 220 ° C-222 ° C, space velocity: 2000 h-1 and water / gas ratio: 0.7) for 72 hours, and then changes in the catalyst phase were determined.

The results are shown in Figures 1, 2 and 3. It can be seen from Figures 1 and 2 that substantially no changes were detected on the CT-4 catalyst of the invention after hydrothermal treatment and no hydration peaks occurred. This indicates that no hydroxide was formed in the hydrothermal treatment, while all commercial catalysts C25-2-02, QC-02 and EB-4 showed hydration peaks after hydrothermal treatment (these are peaks seen between 10 and 20). ), which indicates that these catalysts are hydrated. It can be seen from Figure 3 that after hydrothermal treatment, none of the inventive CT-1, CT-2, CT-3 and T-4 catalysts exhibited any hydration and in these cases no hydration peak was formed. Further, the strength of each fresh sample, the cooked sample and the hydrothermally treated sample of the inventive catalyst and commercial catalysts was measured. The data obtained are shown in Table 1, from which it can be seen that not all catalysts of the invention have not only better strength than the commercial C25-2-02 catalyst, but also

9 9 ·· · ♦ 98

9 9 9 9 9 9 9 9 9 9 9 9 9 9

999,999 9,999,999

9

Higher retention ratio after cooking or hydrothermal treatment, indicating that the catalysts of the invention have an extremely high stability.

Example 3 Catalyst test in the reaction

The evaluation of the CT-4 catalyst according to the invention under simulated conditions was performed under the conditions indicated, including the results of this evaluation in Table 3.

The conditions under which the catalyst was evaluated were as follows: the amount of catalytic charge was 50 ml and the supported catalyst was diluted with α-Al 2 O 3 beads to a total volume of 100 ml with a 1: 1 volume ratio of Al 2 O 3 bead / catalyst.

The catalyst sulfurization conditions were: Pressure: 1.5 MPa, Temperature: 260 ° C, Spatial velocity: 1000 h ^-1 Sulfurization time: 20 h.

Table 1.

Carrier C. TiO ₂ wt. % La ₂ O ₃ wt. % ZnO wt. % MgO % by weight Al ₂ O ₃ wt. % Z-1 63.3 1.9 9.3 25.4 Z-2 62.9 2.5 9.3 25.3 Z-3 53.4 3.3 43.3 Z-4 45.7 3.6 13.6 37.1 Z-5 78.2 9.4 12.4 Z-6 37.4 9.0 23.2 30.4 Z-7 64.3 0.01 9.6 26.1 Z-8 64.31 0.09 9.6 26.1

♦ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ

Table 2

Batch Catalyst Catalyst strength according to the invention N / cm commercial catalyst (N / cm) CT-1 CT-2 CT-3 CT-4 C 25-2-02 Fresh catalyst 126 129 134 136 86 Boiled Strength 108 116 119 120 64 catalyst Retention ratio% 85.7 89.9 88.8 88.2 74.4 Hydrothermally Strength 114 112 118 116 67 processed catalyst Retention ratio% 90.5 85.7 88.1 85.3 77.9

Table 3

Pressure (MPa) Spatial speed (h->) Ratio water/ gas Tvstup (° C) WHAT (% by volume) Conversion WHAT (%) input exit 1.5 1000 1.0 260.6 5.89 0.47 91.58 3.8 3000 0.76 260.0 5.49 0.36 93.11 3.8 2000 0.76 260.1 5.41 0.27 94.75 3.8 2000 0.63 260.0 5.41 0.30 94.16 3.8 2000 0.63 220 5.20 0.34 93.14 3.8 2000 0.63 215 5.29 0.30 94.04 3.8 2000 0.63 210 5.16 0.28 94.31 3.8 2000 0.63 210 3.77 0.20 94.51 3.8 2000 0.63 210 1.67 0.10 94.52 3.8 2000 0.63 205 3.44 0.21 93.69

99 * 9

Claims (20)

Catalyst for the conversion of carbon monoxide by water vapor resistant to sulfur, comprising cobalt and molybdenum compounds as active ingredient, alkali metal compound as promoter, porous aluminum compound and porous magnesium compound, or a combination thereof as a catalyst support skeletal material, one or more compounds selected from the group of rare-earth metal compounds, zinc compounds as an anti-hydrating adjuvant, and a titanium compound, the titanium compound being in the range of 30 wt. % to 80 wt. %, these percentages being calculated on the total weight of the calcined carrier and the titanium compound being calculated as titanium dioxide. Catalyst according to claim 1, characterized in that the content of cobalt compounds and the content of molybdenum compound as active components of the catalyst are: MOO 3: 5 wt% to 20 wt%, CoO: 0.5 wt% to 5 wt% these percentages being calculated on the total weight of the catalyst. Catalyst according to claim 1, characterized in that the content of said alkali metal promoter is 0.1% to 20% by weight, the percentages being calculated on the total weight of the catalyst, the content of the alkali metal compounds being calculated as if they were present in the form of oxides and said alkali metal may be potassium or sodium. Catalyst according to any one of claims 1-3, characterized in that the content of said noble metal compounds is 44%. 4 4 · 4 * 4 «· 4 · 4 4 4 4« 444 444 444 444 444 4 4 4 4 4 4 The soils are 0.01 wt% to 10 wt% of the total weight of the calcined carrier, calculated as oxide. Catalyst according to any one of claims 1-3, characterized in that said anti-hydration adjuvant is one or more compounds selected from nitrates or oxides of lanthanum and nitrates or oxides of cerium. Catalyst according to any one of claims 1-3, characterized in that said anti-hydrating auxiliary is nitrate or lanthanum oxide. Catalyst according to claim 6, characterized in that the content of said nitrates or lanthanum oxides is 0.01% to 10% by weight of the total weight of the calcined carrier, calculated as oxide. Catalyst according to any one of claims 1-3, characterized in that said zinc compound is one or more compounds selected from zinc oxides and thermally decomposable zinc compounds which can decompose into zinc oxide when heated. Catalyst according to any one of claims 1-3, characterized in that said anti-hydrating auxiliary is zinc nitrate or zinc oxide. Catalyst according to any one of claims 1-3, characterized in that the content of zinc compounds is 0.10% to 10% by weight of the total weight of the calcined support, calculated as oxide. * ·· · -15 ´ · * «» · 9 999 9 9 9 9 99 9 * 99 99 9 9 9 999 999 9 9 99 99 The catalyst of any one of claims 1-3, wherein said titanium compound is one or more selected from the group consisting of titanium dioxide, titanium hydroxide, metatitanium acid, titanium dioxide, rutile or anatase. A process for the preparation of a water-resistant carbon monoxide-converting carbon monoxide conversion catalyst according to any one of claims 1-11, comprising the following steps: a) mixing the porous aluminum compound and / or the porous magnesium compound with one or more compounds selected from noble metal compounds and zinc compounds as anti-hydration auxiliary compounds and calcining the resulting mixture and then crushing the decomposed solid product; b) mixing the mixture obtained in step a) in the dry state with the titanium compound, subsequently extruding the resulting mixture into pieces and calcining the extruded pieces of the catalyst support; and c) preparing a co-impregnating solution from the molybdenum and cobalt compounds as catalyst and alkali compound active ingredients, impregnating the support obtained in step b) with this solution, then calcining and decomposing the impregnated support. The method of claim 12, wherein said porous aluminum compounds and the magnesium compounds are one or more compounds selected from the group consisting of aluminum hydroxide, pseudobohmite, gypsum, alumina, magnesium hydroxide, magnesium carbonate, magnesium oxide, and magnesium oxide. alike. 0 0 • 0 0000 16 · - 00 00 0 0 0 0 0 0 0 0 0 0 000 0 0 0 0 00 00 0 0 0 0 0 · 0 0 000 000 0 0 14. The method of claim 12, wherein said anti-hydration adjuvant is one or more compounds selected from the group consisting of nitrates or oxides of lanthanum and nitrates or oxides of cerium. 15. The method of claim 12 wherein said titanium compound is one or more selected from the group consisting of titanium dioxide, titanium hydroxide, metatitanium acid, titanium dioxide, rutile, and anatase. The method of claim 12, wherein the content of the rare earth metal compound is 0.01 wt% to 10 wt% of the total weight of the calcined carrier (calculated as oxide). The method of claim 12, wherein the zinc compound content is 0.1 wt% to 10 wt% of the total weight of the calcined carrier (calculated as oxide). The method of claim 17, wherein said zinc compound is one or more compounds selected from the group consisting of zinc oxide and thermally decomposable zinc compounds that are degradable to zinc oxide when heated. 19. The method of claim 17 wherein said zinc compound is zinc nitrate or zinc oxide. 20. The process of claim 12 wherein said rare earth metal compounds are lanthanum nitrates or oxides.