KR20190017898A - A method for reducing the sulfur content of anatase titania and a method for reducing the sulfur content - Google Patents

Abstract

The present invention relates to the field of heterogeneous catalysts. More particularly, the present invention relates to a method for reducing the sulfur content of stabilized titania, the material thus obtained and the use of materials for producing carrier materials of heterogeneous catalysts.

Description

A method for reducing the sulfur content of anatase titania and a method for reducing the sulfur content

The present invention relates to the field of heterogeneous catalysts. More particularly, the present invention relates to a method for reducing the sulfur content of stabilized titania, the material thus obtained and the use of materials for producing carrier materials of heterogeneous catalysts.

Titanium dioxide is a well known material for the production of heterogeneous catalysts. Titanium dioxide has widespread application as a catalytic material (eg Klaus catalyst) or as a catalytic support (eg selective catalytic reduction of nitrogen oxides (SCR) or Fisher-Tropsch) .

In the dominant and, in most cases, preferred polymorph for heterogeneous catalysts is the anatase crystal phase. The production of anatase type TiO ₂ on a large industrial scale depends on the so-called sulphate process. In the sulfuric acid method, titanium-rich raw materials (ilmenite or Ti-slag) are first reacted with concentrated sulfuric acid to form TiOSO ₄ . When hydrolyzed, fine particulate anatase type TiO ₂ having a high water content is obtained (so-called metatitanic acid having the general formula TiO (OH) ₂ ). After the subsequent purification step, which involves a reduction and washing process, pure anatase TiO ₂ can be obtained.

Another procedure for preparing anatase type TiO ₂ is flame hydrolysis of TiCl ₄ , wherein only a mixture of rutile and anatase is obtained.

The performance of heterogeneous catalysts often depends on their purity. Stray ions can affect the overall conversion and / or selectivity of the catalytic process. Typically unwanted impurities are phosphorus, sulfur, heavy metals, alkaline and alkaline earth metals.

For example, syngas, CO and H ₂ (syngas, CO ₂ S _y ) are formed because sulfur reacts with the catalytically active component cobalt to form cobalt sulphate (Co _x S _y ) Fischer-Tropsch synthesis of carbonic acid water from a mixture of sulfuric acid and sulfuric acid is very sensitive to sulfur impurities. The typical sulfur concentration of the FT-catalyst is less than 150 ppm, preferably less than 100 ppm. The major impurities in the anatase TiO ₂ produced in the sulfuric acid process are sulfur produced from adherent sulfuric acid during the manufacturing process. Other stray ion impurities are in the ppm range of 1 digit or lower 2 digits, and are usually uncritical.

The performance of the heterogeneous catalyst also depends on its physical properties. Very uniform dispersion of the catalytically active material on the carrier is often a prerequisite for observing high conversions. In order to ensure maximum dispersion of the catalytic active center, the customarily large specific surface area of the support is important.

In summary, anatase-type TiO ₂ can be used on a large scale for industrial applications, for catalytic applications, which exhibit both i) large specific surface area (BET> 40 m 2 / g) and ii) low sulfur concentration (<150 ppm S) There is a demand for being.

From a manufacturing standpoint, the only industry-wide scale of anatase-type TiO2 is possible, and the cost-effective manufacturing process is a sulfuric acid process. The main problem with this process is that the sulfur content in the final product is high, and sulfur is known to be detrimental to many catalytic applications. Thus, a process that enables the production of anatase type TiO ₂ on a large industrial scale, with a high specific surface area (> 40 m < 2 &gt; / g) and a low sulfur content (&lt; 150 ppm S)

Various techniques have been developed to reduce the concentration of sulfur in anatase type TiO ₂ . The most commonly used technique is washing with water. Typically, the sulfuric acid containing anatase TiO ₂ is suspended in water and washed on a filter medium (e.g., a filter press). The washing process is carried out using cold deionized water or preferably hot deionized water. The minimum concentration of sulfur that can be obtained by this process is in the range of 0.1 - 0.5 wt%.

When the excess sulfuric acid is reacted with an appropriate base (such as NaOH, aqueous ammonia solution) and the salt formed by the excess washing process using demineralized water is removed, the concentration of sulfur can be greatly reduced to a level of 0.03-0.2 wt%. Especially when basic solutions of metals (eg NaOH or KOH) are used, the use of an excess of base to obtain a minimum level of sulfuric acid will not remove the metal ions from the anatase by washing, exist.

A step of lowering the sulfur concentration can also be carried out by successive washing cycles by excess treatment with strong acid and by successive metal ions removal by an acidic washing process. In this case, it is preferable to use an acid (eg acetic acid) which can be easily removed in the washing step or in the subsequent heating step.

In the process of producing pigmentary grade titanium dioxide, sulfur is removed by thermal decomposition of sulfuric acid. At temperatures above 500 ° C, it is observed that sulfuric acid contamination is greatly reduced, but two processes also occur in this heat treatment process. I) the TiO2 particles undergo grain growth, the specific surface area becomes very large and irreversibly decreases, and ii) at this temperature, a phase transformation from the anatase polymorph to the rutile polymorph occurs. These two processes are preferred for obtaining pigment TiO ₂ with low BET (<20 m 2 / g) and rutile type TiO ₂ , but the anatase TiO ₂ with a large surface area and low sulfur content In relation, such procedures are prohibited from being used.

As a result, there is no process that makes it possible to produce anatase type TiO ₂ with the following characteristics by large-scale industrial production. 1. an ultra low sulfur content (<150 ppm), 2. a BET surface area of greater than 20 m 2 / g, preferably greater than 30 m 2 / g, more preferably greater than 40 m 2 / g, TiO _{2 in the} anatase phase.

There is a need for an anatase type catalyst carrier material that is readily accessible through large industrial production and has a low specific surface area and low sulfur content.

In this connection it has been surprisingly found that surprisingly anatase type titanium dioxide doped with an appropriate amount of silica and / or zirconium oxide and / or aluminum oxide can be treated at a temperature high enough to decompose sulfuric acid, while maintaining a substantially wide specific surface area It was discovered that In this regard, the term " thermal stabilization " refers to the use of anatase type TiO2 in such a way that i) the rutilization temperature is shifted to a higher temperature and ii) the tendency towards BET loss is reduced. ₂ &lt; / RTI &gt; is stabilized.

In a typical experiment according to the present invention, anatase type TiO2 having an SiO ₂ content of 8% by weight was heated for 1 hour at a temperature as high as 1000 ° C for 1 hour. The resulting powder exhibits a BET surface area of about 50-70 m &lt; 2 &gt; / g and residual sulfur contamination of less than 50 ppm. The degree of resistance to thermal aging of anatase largely depends on the amount of silica added. Larger amounts of silica have a strong influence on aging characteristics, while small amounts cause only minor resistance.

In addition to these effects, silica can also affect the catalytic properties of the final catalyst. Silica can change overall performance by altering the preference and / or conversion rate of the catalyst. Depending on the specific application and the specific requirements relating to the BET surface area, SiO2, residual S content, correct material and calcination conditions should be individually adjusted for each intended use. Overall, the high calcination temperature reduces both the residual S concentration and the specific surface area.

Basically, any element capable of stabilizing the anatase polymorph in the context of the present invention may be used. Among the many other common elements associated with catalytic applications are Si, Al, Zr [J Mater Sci (2011) 46: 855-874].

The incorporation of such stabilizing elements can be achieved by various other synthetic approaches. With respect to the materials of the present invention, the following alternative methods are suitable. 1. The precipitation of the SiO ₂ on TiO _2. 2. Co-precipitation or co-hydrolysis of TiO2 and SiO2. 3. Mixture of TiO ₂ sol and SiO ₂ sol. 4. Treatment of TiO ₂ with SiO ₂ sol. 5. Treatment of TiO ₂ with a SiO ₂ precursor followed by hydrolysis and / or oxidation to form SiO ₂ . 6. Mixture of TiO ₂ and SiO ₂ .

Therefore, the present invention is characterized in that the content of at least one compound selected from the oxides of Si, Al and Zr has a content of 2-50% by weight, preferably 2-30% by weight, in terms of oxide, in the total weight of the oxide , An anatase titanium dioxide having a sulfur content of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of the oxide.

The anatase substance of the present invention preferably has an alkali content of less than 200 ppm, preferably less than 100 ppm, such as Na ⁺ , so as to avoid the negative influence of alkali on the stability of the substance in use.

According to the present invention, anatase titanium dioxide is preferably obtained by a sulfuric acid process, wherein the anatase titanium dioxide is obtained as their hydrated forms, including titanium dioxide and metatitanic acid. The metatitanic acid and the hydrate form of titania which are used simultaneously in the present specification can be expressed by the formula TiO _(2-x) (OH) _2x (0? X? 1) and also include titania. The metatitanic acid is then further processed to incorporate a stabilizer selected from Si, Zr and / or Al in oxide form or in their hydrate form, followed by treatment with a sulfur-containing compound such as sulfuric acid as the remainder of the sulfuric acid process And calcined to be decomposed. In the calcination process, the hydrate form is converted to an oxide and the content of hydrate is reduced to a zero state, which is clear to the ordinarily skilled artisan.

The term " anatase titanium dioxide or anatase titania " used in accordance with the present invention means that at least 95 wt%, preferably 98 wt%, and most preferably 100% of the titania is present in the anatase form. Generally, the anatase phase has a crystallite size of 5-50 nm. Thus, with respect to the material of the present invention, most of the crystalline phases of the particles are present in the anatase phase, after drying at 105 캜 for at least 120 minutes before the calcining treatment and after the calcining treatment due to stabilization. That is, after subtracting the linear base, the height (reflex (101)) of the largest peak of the anatase structure relative to the height of the highest peak of the rutile structure (reflex (100)) is at least 5: Preferably at least 10: 1. Most preferably, XRD analysis shows only anatase peaks. X-rays are taken with respect to measuring the phase and crystallite size, in particular the phase identification, by Scherrer. In this regard, the intensity of the Bragg condition after diffraction in the lattice plane of the crystalline X-ray is measured relative to the diffraction angle 2 theta. X-ray diffraction is characteristic of the phase.

The drying used in connection with the present invention is drying at a temperature in excess of &lt; RTI ID = 0.0 &gt; 105 C &lt; / RTI &gt; Although all large industrial techniques such as spin-flash or spray drying can be applied, drying is not limited to the techniques mentioned.

The calcination step used in accordance with the present invention is a step of decomposing the remaining sulfur containing compounds such as sulfuric acid to maintain the titania content in the anatase form and to decompose the remaining sulfur containing compounds to less than 150 ppm, Preferably for a period of time sufficient to reduce the sulfur content to a concentration of less than 80 ppm, preferably for a period of from 30 minutes to 1200 minutes, at an elevated temperature of greater than 500 DEG C, preferably from 800 DEG C to 1200 DEG C Quot; means treating the stabilized anatase titania. The calcination step can be performed in a conventional calcination device under atmospheric pressure so that the sulfur-containing components can evaporate from the material.

As used herein, the weight ratio, ppm-value, or percentage refers to the weight of the material after calcination.

Due to the high temperature treatment, harmful agglomeration may occur to the subsequent process for forming the catalyst. Deggglomeration of the calcined material may be required by the milling process. Both wet and dry milling techniques can be applied, and conventional techniques are ball milling or jet milling. An optional sieving step may be followed to confirm that the coarse particles have been removed.

The anatase TiO ₂ thus obtained may function as a catalyst support material. The catalyst support material may be selected from the group consisting of Co, Ni, Fe, W, V, Cr, Mo, Ce, Ag, Au, Pt, Pd, Ru, The catalyst carrier material is further treated with at least one catalytically active metal selected from Rh, Cu, or mixtures thereof, thereby obtaining a loaded metal catalyst carrier material. And a catalyst active metal selected from Co, Ni, Fe, W, V, Cr, Mo, Ce, Ag, Au, Pt, Pd, Ru, Rh, Cu, Precursor compounds may be used. Treatment of the carrier material with one precursor compound of a catalytically active metal or a mixture thereof can be carried out by various techniques. Conventional methods include incipient wetness or an excess solvent method. A deposition reaction such as hydrolysis may also be applied to bring the catalytically active metal or its precursor into contact with the catalyst carrier material. A compound of a catalytically active metal which can be selected from Co, Ni, Fe, W, V, Cr, Mo, Ce, Ag, Au, Pt, Pd, Ru, Rh, Cu, Can be used in an amount to achieve a loading of 1-50 wt%, preferably 5-30 wt%, more preferably 8-20 wt%, in terms of oxides of the total weight of the final catalyst carrier material .

Accordingly, the present invention encompasses the following.

- calculated as oxides, the content of at least one compound selected from oxides of Si, Al and Zr in an amount of 2-50% by weight, preferably 2-30% by weight, based on the total weight of the oxide Anatase titanium dioxide having a sulfur content of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of said oxide;

- the content of at least one compound selected from oxides of Si, Al and Zr in terms of oxides has an amount of 3-20% by weight, preferably 4-12% by weight, based on the total weight of the oxide, Anatase titanium dioxide having a sulfur content of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, by weight;

In terms of oxides, the content of SiO ₂ is in the range of 2-30% by weight, preferably 3-20% by weight, more preferably 4-12% by weight, based on the total weight of the oxide, Anatase titanium dioxide having a sulfur content of less than 100 ppm, preferably less than 80 ppm;

- calculated as oxides, the content of at least one compound selected from oxides of Si, Al and Zr is 2-50% by weight, preferably 2-30% by weight, more preferably 2-50% by weight, Has a quantity of from 3 to 20% by weight, most preferably from 4 to 12% by weight and a sulfur content of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of said oxide A method for preparing the anatase titanium dioxide of the invention is characterized in that in the aqueous medium a titanium compound selected from metatitanic acid or titanium sulphate is selected from oxides and / or hydroxides of Si, Al and Zr or their precursors And precipitates at least one compound selected from oxides and / or hydroxides of Si, Al and Zr, and - at least one compound selected from the group consisting of Treating the obtained product so as to reduce the content of alkali to a level of up to 200 ppm when the content of the alkali exceeds 200 ppm, and the product is selectively filtered, optionally washed with water, and optionally dried, For a time sufficient to decompose the residual sulfur-containing compound such as sulfuric acid to a level of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, relative to the total weight of the oxide, preferably from 0.5 to 12 For a period of time, the product is calcined at a temperature above 500 ° C, preferably between 800 ° C and 1200 ° C;

As a method for producing anatase titanium dioxide of the present invention, there is a method in which metatitanic acid is mixed with a SiO ₂ precursor compound, at least one of the oxides and / or hydroxides of Si is precipitated, When the content exceeds 200 ppm, the obtained product is treated so as to reduce the content of alkali to a maximum of 200 ppm, and the obtained product is selectively filtered, selectively washed, selectively dried, For a time sufficient to decompose the residual sulfur-containing compound, such as sulfuric acid, to a level of less than 100 ppm, preferably less than 80 ppm, based on the total weight of the oxide, preferably 0.5 to 12 hours, Lt; 0 &gt; C, preferably 800 &lt; 0 &gt; C to 1200 &lt; 0 &gt;C;

A method for preparing anatase titanium dioxide comprising the steps of: mixing a titanium compound selected from TiO ₂ sol (sol) with a SiO ₂ sol, adjusting the pH to obtain a precipitate and adjusting the content of alkali Exceeds 200 ppm, the resulting precipitate is treated so as to reduce the content of alkali to a level of up to 200 ppm, and the obtained product is selectively filtered, selectively washed, selectively dried, and the obtained product is washed with sulfuric acid For a time sufficient to decompose to a level of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of the oxide, preferably from 0.5 to 12 hours Gt; 500 C &lt; / RTI &gt; and preferably 800 &lt; 0 &gt; C to 1200 &lt; 0 &gt;C;

Anatase titania having a content of a stabilizing agent can be produced by reacting a residual sulfur containing compound such as sulfuric acid with a reducing agent containing 150 to 150 g of the total weight of the oxide, for a time sufficient to decompose to a level of less than 100 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, preferably at least 30 minutes, at a temperature above 500 ° C, preferably between 800 ° C and 1200 ° C Wherein the stabilizer is selected from oxides of Si, Al and Zr and the calculated amount of stabilizer is in the range of 2-50% by weight of the total weight of the oxide, By weight to 2 - 30% by weight;

- stabilized anatase titania having an amount of at least one compound selected from oxides of Si, Al and Zr, in terms of oxide, of 2-50% by weight, preferably 2-30% by weight, based on the total weight of the oxide The use of a calcining treatment at temperatures above 500 DEG C to reduce the sulfur content of the oxide to less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of the oxide;

Catalytic reactions, in particular gaseous liquids such as Fisher-Tropsch catalysts, selective catalytic reduction (SCR), oxidation catalysts, photocatalysts, hydrotreating catalysts, Klaus catalysts, phthalic acid catalysts The use of anatase titanium dioxide according to the invention, obtainable according to the process of the invention, for use as a catalyst or catalyst support in gas to liquid reactions.

A catalyst or catalyst carrier containing anatase titanium dioxide which can be obtained according to the invention or the process of the invention.

The present invention is further illustrated by the following examples and comparative examples.

Experimental part

Analysis method

TiO ₂  Measurement of polymorph

To determine the TiO ₂ polymorph, X-ray diffraction (XRD) analysis is applied. This is done for a diffraction angle 2 theta in a conventional XRD instrument (set-up) where the intensity of the diffracted X-ray is measured. The evaluation of the obtained XRD pattern is carried out using a JCPDS-database. The usual conditions of analysis are as follows. 2 Theta = 10 [deg.] To 70 [deg.]; 2 Theta's incremental step = 0.02 °, measurement time per incremental angle = 1.2 s.

SiO ₂  Content measurement

The material is digested in H ₂ SO ₄ / (NH ₄ ) ₂ SO ₄ and diluted with deionized water. The residue and determination of the filter cake after being washed with sulfuric acid and calcination treatment, the SiO ₂ content is obtained.

TiO ₂  Content measurement

Degradation (digestion) of the material is performed using a _{H2SO4 / (NH 4) 2 SO} 4 and KHSO _4. The reduction of Ti ⁴⁺ to Ti ²⁺ is then carried out and finally the TiO ₂ content is obtained by titration using ammonia iron (III) sulphate (NH ₄ SCN as indicator).

Measurement of S-content

The S-content is obtained by the elemental analyzer Euro EA (Hekatech). The sample is continued in an oxygen environment and the gas is analyzed by gas chromatography. The S-content is calculated from the area of the chromatogram.

Measurement of specific surface area

The specific surface area is measured by the nitrogen adsorption technique (BET method) according to DIN ISO 9277. Five points between 0.1 and 0.3 p / p _o are evaluated. The equipment used was Autosorb 6 or 6B (Quantachrome GmbH).

Example 1

SiO ₂ (13.1 wt.%) Was introduced by co-precipitation of TiO ₂ and SiO ₂ from solutions containing TiOSO ₄ and Na ₂ SiO ₃ . 352 L of a Na ₂ SiO ₃ solution (94 g / L SiO ₂ ) and 2220 L of a TiOSO ₄ solution (103 g / L TiO ₂ ) were simultaneously pumped over a period of 270 minutes into a stirred reaction vessel containing 960 L water (pumped over). In the course of the reaction, the pH was maintained at 5 using ammonia solution. After the addition was complete, the reaction was heated to 75 &lt; 0 &gt; C for 1 hour to complete the reaction. Hydrothermal aging was then carried out for 4 hours at 9.5-10 bar, 170-180 &lt; 0 &gt; C. Finally, the resulting reaction mixture was filtered and washed with deionized water. The product was obtained after spray drying at 350 ° C. BET was 100 m &lt; 2 &gt; / g, and S content was 4000 ppm.

Example 2

On the basis of the meta-titanic acid and Na ₂ SiO _3, the SiO SiO ₂ / TiO ₂ powder content is ₂ 8.5% by weight have been manufactured, and then pH- adjusting step, washing with deionized water to a final filtration, and thus obtained material The steps followed. The SiO ₂ / TiO ₂ powder obtained after drying has a BET of 334 m 2 / g and a sulfur content of 1100 mg / kg.

Example 3

943 g of metatitanic acid (29.2 wt.% Of TiO ₂ ) was diluted with deionized water to 150 g / L. 78.5 g of ZrOCl ₂ x ₈ H ₂ O was added and the temperature was raised to 50 ° C. Then, 68 mL (358 g / L SiO ₂ ) of sodium silicate (Na ₂ SiO ₃ ) was added. After the addition was complete, aqueous NaOH (50 wt% NaOH) was added at 50 캜 until the pH reached 5.25. The white precipitate was filtered and washed with deionized water until the conductivity of the filtrate was less than 100 μS / cm. The remaining filter cake was dried at 105 占 폚. The product had a BET surface area of 329 m &lt; 2 &gt; / g and an S content of &gt; 1000 ppm. The contents of SiO ₂ and ZrO ₂ were 7.7% by weight and 10.8% by weight, respectively.

Example 4

Example 4 was carried out in the same manner as in Example 3, except that the order of addition of ZrOCl ₂ x ₈ H ₂ O and sodium silicate was changed. With respect to Example 4, a Na ₂ SiO ₃ solution was added first, followed by ZrOCl ₂ x ₈ H ₂ O. The contents of SiO ₂ and ZrO ₂ were 6.8 wt% and 10.4 wt%, respectively. The BET surface area was 302 m &lt; 2 &gt; / g and the S-content was 3300 ppm.

Comparative Example 1

Hombikat 8602 (commercial product). The BET surface area was 321 m &lt; 2 &gt; / g and the S content was 4700 ppm.

Comparative Example 2

Neutralized using NaOH, and washed with deionized water to purify commercially available Hombikat 8602. As a result of the purification, the sulfur content before calcination was 0.2 wt% (2000 ppm) and the BET surface area was 351 m 2 / g.

Comparative Example 3

A rutile suspension was prepared according to Example 1a of DE 10333029A1. To prepare the rutile suspension, NaOH was added at pH 6.0, 6.2 at 60 캜, the solid was filtered and washed with deionized water until the conductivity of the filtrate was less than 100 μS / cm. The resulting filter cake was re-slurried and spray dried. The BET surface area was 105 m &lt; 2 &gt; / g and the S-content was 70 ppm.

Comparative Example 4

As received, commercially available Aerosil P25 (from Evonik). The BET surface area was 55 m 2 / g and S <30 ppm.

Comparative Example 5

Titanium oxychloride (Titaniumoxychloride) 300 mL (145 g / L TiO 2) was diluted to 3 L with deionized water. Then 4 g of oxalic acid dihydrate was added and a 15% aqueous solution of NaOH was treated to the reaction mixture while the temperature was kept below 20 ° C to precipitate a white solid. The final pH was 6.2. After filtration, the white solid was washed with deionized water to give a filtrate conductivity <100 μS / cm. Re-slurry and spray drying were performed to obtain a final product having a BET of 359 m < 2 &gt; / g and S &lt; 30 ppm.

calcination

All calcination was carried out in a muffle kiln. The material was placed inside a ceramic seggars (corundum) and heated at 1000 占 폚 for 1 hour. Prior to XRD, BET and SO ₄ analysis, the resulting powder was carefully milled and homogenized. Various SiO ₂ before and after aging for one hour at 1000 ℃ - BET surface area and a sulfur content of the treated TiO ₂ anatase support is shown in Table 1.

Fischer-Tropsch synthesis (FTS)

The FTS test was performed using a 32-fold parallel reactor. The powder was crushed after being compressed. The samples were treated with Co (NO ₃ ) ₂ through impregnation so that the final Co loading could be 10 wt% based on the total weight of the dried and reduced catalyst. With respect to the catalyst test, a fraction of 125-160 mu m was used, and each catalyst unit was charged with the amount of catalyst capable of achieving a 40 mg Co-metal loading. Before performing the catalytic test, the catalyst was activated with H ₂ (25% in Ar) was diluted in 350 ℃ (1K / min heating lamp). Catalyst testing was then carried out at 20 bar, feeding at 1.56 L / h per reactor. The H ₂ / CO ratio was 2 (10% Ar in the feed) and the temperature of the catalyst test was 220 ° C.

In the Fischer-Tropsch synthesis, CO and H ₂ were contacted at elevated pressure and temperature to react and produce hydrocarbons. Evonik P25 is a known TiO ₂ -based catalyst carrier for this application. In order to have an economical FTS process as a whole, the catalyst should meet the following characteristics. 1. High CO conversion (X _co ,%). 2. High C ₅₊ productivity (productivity, Pc5 +, g _{C5 +} / (g _co h)). 3. Low methane selectivity (S _CH4 ,%). 4. Low CO ₂ selectivity (S _co2 ,%).

The goal of the FTS is to produce long chain hydrocarbons. In particular, hydrocarbons having more than 5 carbon atoms serve more than 5 carbon atoms, for example as a feedstock in connection with high quality diesel, kerosene or long chain waxes. Chlorohydrocarbons are of interest. Syngas (H ₂ / CO-mixture) is often produced from methane by reacting methane with H ₂ O (steam reforming) to obtain CO and H ₂ . Due to the adverse reaction, the amount of CO and H _{2 that} can be used in connection with FTS synthesis will decrease. High methane (CH ₄ ) selectivity in FTS indicates a high conversion of CO and H ₂ to CH ₄ , and vice versa. Therefore, CH ₄ selectivity is to be maintained at the lowest possible level. Furthermore, under reaction conditions, CO must react with H ₂ O to form CO ₂ and H ₂ (water gas shift reaction). This will result in a reduction in the concentration of carbon atoms that can be used in connection with FTS. High CO ₂ selectivity indicates a high conversion of CO to CO ₂ , and vice versa. Therefore, the CO ₂ selectivity should be low in relation to the FTS catalyst.

In addition, the CO conversion (amount of converted CO) must be high, and moreover, the amount of hydrocarbons having more than 5 carbon atoms must also be high. The latter parameter is indicated by the amount of hydrocarbons having more than 5 carbon atoms generated within one hour for one gram of metal cobalt.

In connection with all four of these parameters, Table 3 clearly shows that the product according to the invention exerts excellent properties when used as a catalyst carrier in FTS.

Raw materials and physical properties used Sample Calcination After calcination at 1000 ° C for 1 hour BET, m &lt; 2 &gt; / g S, mg / kg TiO ₂ polymorph BET, m &lt; 2 &gt; / g S, mg / kg TiO ₂ polymorph Example 1 100 4000 Anatase 60 40 Anatase Example 2 334 1100 Anatase 70 <30 Anatase Example 3 329 > 1000 Anatase 77 <30 Anatase Example 4 302 3300 Anatase 52 <30 Anatase Comparative Example 1 321 4700 Anatase 3 <30 Rutile Comparative Example 2 351 2000 Anatase 3 <30 Rutile

An overview of the carrier materials used for FTS Sample BET, m &lt; 2 &gt; / g S, mg / kg TiO ₂ , polymorph Example 1 (after 1 hour at 1000 占 폚) 70 <30 Anatase Example 2 (after 1 hour at 1000 占 폚) 77 <30 Anatase Example 3 (after 1 hour at 1000 占 폚) 52 <30 Anatase Comparative Example 3 105 70 Rutile Comparative Example 4 55 <30 Anatase / Rutile Comparative Example 5 359 <30 Anatase

Example Fischer-Tropsch synthesis data of light comparative example Sample X _co (%) S _CH4 (%) P _{c5 +} g _{C5 +} / (g _Co h) S _co (%) Example 2 54 7.2 3.46 0.6 Example 3 55.2 7.8 3.35 0.7 Example 4 52.9 7.7 3.3 0.6 Comparative Example 3 12.6 9.4 0.74 n.d. Comparative Example 4 20.6 9.5 1.18 n.d. Comparative Example 5 0.5 31.3 0.02 n.d. n.d. = CO conversion is too low to be measured (not determined).

The above results according to the catalyst test and the examples and comparative examples of the present invention show that the combination of the characteristics of the material of the present invention, that is, the high specific surface area and the anatase content, and the low sulfur content, Show.

Claims (10)

The calculated amount of at least one compound selected from oxides of Si, Al and Zr has a content of 2-50% by weight, preferably 2-30% by weight, based on the total weight of the oxide , An anatase titanium dioxide having a sulfur content of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of the oxide.
The method according to claim 1,
The content of at least one compound selected from oxides of Si, Al and Zr in terms of oxides has an amount of 3 to 20% by weight, preferably 4 to 12% by weight, based on the total weight of the oxide, An anatase titanium dioxide having a sulfur content of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm.
The method according to claim 1,
In terms of oxides, has a content of SiO _{2 in} an amount of 2-30 wt%, preferably 3-20 wt%, more preferably 4-12 wt%, based on the total weight of the oxide, An anatase titanium dioxide having a sulfur content of less than 100 ppm, preferably less than 80 ppm.
The calculated amount of at least one compound selected from oxides of Si, Al and Zr is 2-50% by weight, preferably 2-30% by weight, more preferably 2-30% by weight, based on the total weight of the oxide, Preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of said oxide, of an amount of from 3 to 20% by weight, most preferably from 4 to 12% A method for producing anatase titanium dioxide,
- in an aqueous medium, a titanium compound selected from metatitanic acid or titanium sulfate is mixed with at least one compound selected from oxides and / or hydroxides of Si, Al and Zr or their precursors,
- precipitating at least one compound selected from oxides and / or hydroxides of Si, Al and Zr,
Treating the obtained product so as to reduce the content of alkali to a level of up to 200 ppm if the content of alkali exceeds 200 ppm based on the total weight of said oxide,
The product is optionally filtered, optionally washed with water, and optionally dried,
Then for a time sufficient to decompose the residual sulfur-containing compound such as sulfuric acid to a level of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, relative to the total weight of the oxide, Wherein the product is calcined at a temperature above 500 ° C, preferably between 800 ° C and 1200 ° C, for a period of from 0.5 to 12 hours.
A method for producing the anatase titanium dioxide according to claim 3,
Meta-titanic acid is mixed with the SiO ₂ precursor compound, to precipitate at least one of an oxide and / or hydroxide of Si, when it exceeds the amount of the alkali-200 ppm, based on the total weight of the oxide, up to 200 ppm level, the content of the alkali , The resulting product is selectively filtered, optionally washed, the product obtained is selectively dried, and then the residual sulfur-containing compound, such as sulfuric acid, is added to the total weight of the oxide For a time sufficient to decompose to a level of less than 100 ppm, preferably less than 80 ppm, preferably 0.5 to 12 hours, the product is calcined at a temperature above 500 ° C, preferably between 800 ° C and 1200 ° C How it is processed.
A method for producing the anatase titanium dioxide according to claim 3,
The titanium compound selected from the TiO ₂ sol is mixed with the SiO ₂ sol and the pH is adjusted so as to obtain a precipitate. If the content of the alkali exceeds 200 ppm based on the total weight of the oxide, The resulting product is selectively filtered, optionally washed, selectively dried, and the obtained product is treated with a residual sulfur-containing compound, such as sulfuric acid, in an amount sufficient to reduce the concentration of said oxide For a time sufficient to decompose to a level of less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight, preferably 0.5 to 12 hours, RTI ID = 0.0 &gt; 1200 C. &lt; / RTI &gt;
As a method for reducing the sulfur content of stabilized anatase titania,
An anatase titania having a content of a stabilizing agent may be prepared by reacting a residual sulfur containing compound such as sulfuric acid with less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, calcined at a temperature above 500 ° C, preferably between 800 ° C and 1200 ° C, for a time sufficient to decompose to a level of less than 1 ppm, preferably at least 30 minutes,
Wherein the stabilizer is selected from oxides of Si, Al and Zr,
Wherein the amount of stabilizer is in the range of 2-50 wt.%, Preferably 2-30 wt.%, Of the total weight of the oxide, calculated as oxides.
Use of the calcination treatment at temperatures above 500 ° C to reduce the sulfur content in the stabilized anatase titania to less than 150 ppm, preferably less than 100 ppm, more preferably less than 80 ppm, based on the total weight of the oxide.
Catalyzed reactions, especially of gases such as Fischer-Tropsch catalysts, selective catalytic reduction (SCR), oxidation catalysts, photocatalysts, hydrotreating catalysts, Klaus catalysts, phthalic acid catalysts A process as claimed in any one of claims 1 to 3 for use as a catalyst or catalyst support in gas to liquid reactions or in any one of claims 4 to 7 The use of anatase titanium dioxide which can be obtained according to the process described.
A catalyst or catalyst carrier containing anatase titanium dioxide which can be obtained according to the process as claimed in any one of claims 1 to 3 or according to the process as claimed in any one of claims 4 to 7.