JPH11276897A - Catalyst for hydrolyzing carbonyl sulfide and hydrolysis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert carbonyl sulfide having numbers of base points into hydrogen sulfide by hydrolysis by adding a metal sulfate or a metal carbonate as a cocatalyst to anatase type titanium. SOLUTION: As a method for highly activating a TiO2 carrier, the addition of a cocatalyst is considered. The addition of a metal sulfate and a metal carbonate as a substance of a stable structure is considered. Besides, conversion into a complex oxide is cited to improve the performance of the TiO2 carrier. In general, by the conversion of a metal oxide into a complex metal oxide, the specific surface area increases, and also the heat resistance is improved. Also, solid base points increase. Although the form of a catalyst used in this reaction is not specified, a honeycomb-shaped catalyst is preferable. This catalyst added with a cocatalyst is prepared by a method in which metatitanic acid or titania, a metal sulfate, and a metal carbonate are added, and the mixture is added with a binder, kneaded, molded into a honeycomb, dried, and baked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalyst and a method for converting carbonyl sulfide (COS) contained in coal gasification gas or the like into hydrogen sulfide by hydrolysis.

[0002]

2. Description of the Related Art Sulfur compounds mixed in various kinds of synthesis gas become catalyst poisoning, equipment corrosion and air pollutants in various processes using the synthesis gas as a raw material. A lot of work has been done. In particular, coal gasification gas contains a large amount of sulfur compounds, and when used as gas turbine fuel, hydrogen sulfide and COS must be removed. Among the sulfur compounds, hydrogen sulfide and sulfur dioxide have been relatively easily removed by an alkaline solution washing method, an amine absorption method, or the like. However, since it is difficult to efficiently remove COS by a wet method, it has been converted to hydrogen sulfide by the following hydrolysis reaction.

## STR1 ## to _{COS + H 2 O → H 2} S + CO 2 This is as a hydrolysis catalyst of COS in the gas alumina support catalyst has been mainly used. However, the alumina-supported catalyst has a problem that the process becomes complicated because the durability of the catalyst is difficult when a coexisting gas such as hydrochloric acid is present, and it is necessary to remove hydrochloric acid with a scrubber or the like in advance. .

[0003]

Since ordinary coal gasification gas contains hydrochloric acid of several tens to several hundreds of ppm, development of a catalyst excellent in hydrochloric acid resistance when used in this atmosphere is awaited. Had been. As a carrier having excellent hydrochloric acid resistance, TiO ₂ can be cited, but it does not always have satisfactory performance. Furthermore, the present inventors have made intensive studies on the mechanism of the COS hydrolysis reaction and found that the reaction proceeds according to the following reaction model. From this model, it was considered that the active point of the catalyst was a base point on the catalyst surface, and that a catalyst having more base points had higher performance.

Embedded image In view of the above technical level, the present invention provides a C-containing compound having a large number of base points.
An object of the present invention is to provide a catalyst for hydrolysis of OS and a method for the hydrolysis.

[0004]

(1) A catalyst for hydrolyzing carbonyl sulfide, wherein an anatase type titanium is added and supported as a co-catalyst with a metal sulfate or a metal carbonate. (2) The metal sulfate as a co-catalyst is selected from the group consisting of barium sulfate, calcium sulfate and magnesium sulfate, and the metal carbonate is calcium carbonate, magnesium carbonate, strontium carbonate, barium carbonate, cobalt carbonate, carbonate The carbonyl sulfide hydrolysis catalyst according to (1) or (2), which is selected from the group consisting of zinc, iron carbonate, copper carbonate, nickel carbonate and manganese carbonate. (3) TiO ₂ · SiO ₂ , TiO ₂ · Al ₂ O ₃ , T
iO ₂ · ZrO ₂ , ZrO ₂ · Al ₂ O ₃ , and SiO
_{2. A} catalyst for hydrolyzing carbonyl sulfide, comprising a composite oxide of the group consisting of 2.Al ₂ O ₃ . (4) In the presence of water, in an atmosphere of a reducing gas, (1) to
(4) A method for hydrolyzing carbonyl sulfide, which comprises hydrolyzing carbonyl sulfide in the presence of any of the catalysts.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Addition of a cocatalyst can be considered as a method for highly activating a TiO ₂ carrier. As shown in the above reaction model, addition of a metal sulfate and a metal carbonate can be given as a substance having a basic site and a more stable structure. Examples of the metal sulfate include barium sulfate, calcium sulfate, and magnesium sulfate. Examples of the metal carbonate include calcium carbonate, magnesium carbonate, strontium carbonate, barium carbonate, cobalt carbonate, zinc carbonate, iron carbonate, and copper carbonate.
Nickel carbonate, manganese carbonate and the like. When the above catalyst is prepared, a metal sulfate or a metal carbonate is generally used as a kneading method on a TiO ₂ carrier, although not particularly limited. The amount of the cocatalyst to be added is 0.5 to 30% by weight, preferably 0.1 to 20% by weight.

On the other hand, TiO_TwoComplex acid as high performance carrier
Materialization is mentioned. Generally, metal oxides are mixed metal oxides
When it is made into a material, the specific surface area increases and the heat resistance also improves. Sa
In addition, it has the feature that the solid base point also increases. For example, T
iO_TwoTiO 2 based composite oxides_Two・ SiO_Two, T
iO_Two・ Al_TwoO_Three, TiO_Two・ ZrO_TwoIs raised
You. Further Al_TwoO_Three・ ZrO_TwoAnd SiO_Two・ Al_TwoO
_ThreeAnd other composite oxides have improved hydrochloric acid resistance, specific surface area, and heat resistance.
Carbonyl sulfide is also hydrolyzed due to increased acidity and base point
High performance can be achieved as a catalyst. TiO_Two・ S
iO_Two, TiO_Two・ Al_TwoO_Three, TiO_Two・ ZrO_Two,
Al_TwoO_Three・ ZrO_TwoAnd SiO_Two・ Al _TwoO_ThreeCompound of
The composite ratio of the oxides is in the range of 99: 1 to 1:99, respectively.
You.

The shape of the catalyst applied to the COS hydrolysis reaction is not particularly limited, but a honeycomb-shaped catalyst is preferred. The reason is that when foreign substances such as dust are present, clogging of the catalyst and pressure loss can be prevented.

[0008] With regard to the method of preparing the catalyst, the catalyst of the present invention of the cocatalyst added type is as follows. Methanetitanic acid or titania and the aforementioned metal sulfates,
A method of adding a metal carbonate, adding a binder, kneading, forming a honeycomb, drying and firing. A method of impregnating a slurry solution of a metal sulfate and a metal carbonate into titania formed in a honeycomb shape in advance, followed by drying and firing. The catalyst of the present invention of the composite oxide type may be prepared by adding a binder to a previously prepared composite oxide, kneading the mixture, forming a honeycomb, drying and firing. in this case,
In general, a composite oxide is prepared by adding an alkaline solution such as ammonia to an aqueous solution of a metal salt such as a metal nitrate, chloride, or sulfate of Ti, Si, Al, or Zr and coprecipitating to form a composite hydroxide. In addition, washing, drying and baking can be performed. In this case, the mixing ratio of two kinds of oxides of various composite oxides of Ti, Si, Al and Zr is 99: 1 to 1
It can be in the range of 1:99.

[0009]

EXAMPLES Hereinafter, preparation examples of various carbonyl sulfide hydrolysis catalysts of the present invention will be described, and the catalytic effects of the obtained catalysts will be clarified.

(Example 1) Titania powder (CSP manufactured by Catalyst Chemicals Co., Ltd.)
-003): 4 parts by weight of barium sulfate was added to 100 parts by weight, and ammonia water was added, followed by heating and kneading. Next, 3 parts by weight of glass fiber, 5 parts by weight of kaolin, 5 parts by weight of cellulose acetate as an organic plasticizer, and ammonia water were added to the kneaded material and kneaded. The kneaded material was extruded and formed into a mixture of 5.0
An integral honeycomb molded product having a mm pitch (wall thickness: 1.0 mm) was obtained. The formed article was dried and calcined at 500 ° C. for 5 hours to remove the organic plasticizer, whereby the honeycomb catalyst 1 was dried.
I got

In the method for preparing the above-mentioned honeycomb catalyst 1, in place of barium sulfate, calcium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, strontium carbonate, barium carbonate, cobalt carbonate, zinc carbonate, iron carbonate, copper carbonate, carbonate carbonate 4 parts by weight of nickel and 4 parts by weight of manganese carbonate were added, and honeycomb catalysts 2 to 13 were obtained by the same preparation method as for honeycomb catalyst 1.

(Example 2) An aqueous solution of colloidal silica was added to an aqueous solution of titanyl sulfate (TiOSO ₄ ) at a weight ratio of TiO ₂ to SiO ₂ of 90:10. Next, after heating this solution to 70 ° C., the aqueous ammonia solution was brought to pH =
The mixture was added dropwise with stirring until the mixture became 7, thereby obtaining a coprecipitate slurry. The slurry was stirred and aged at 70 ° C. for 2 hours, and then filtered and washed to obtain a cake. Dry this cake,
Calcination was performed at 500 ° C. for 5 hours to obtain a TiO ₂ .SiO ₂ composite oxide. This composite oxide is referred to as composite oxide 1. 3 parts by weight of glass fiber, 5 parts by weight of kaolin, 5 parts by weight of cellulose acetate, and ammonia water were added to 100 parts by weight of this composite oxide 1 as a binder and kneaded. This kneaded material was formed into a honeycomb in the same manner as in Example 1, and dried and fired to obtain a honeycomb catalyst 14.

In the method for preparing the composite oxide 1,
Aluminum sulphate or ox instead of colloidal silica
Zirconium chloride is weight ratio of TiO2_Two: Al
_TwoO _Three= 90: 10, TiO_Two: ZrO_Two= 90: 10
In the same manner as in the case of the composite oxide 1,
iO_Two・ Al_TwoO_ThreeComposite oxide and TiO_Two・ ZrO_TwoDuplicate
A composite oxide was obtained. This composite oxide is referred to as composite oxides 2 and 3.
You.

Further, in the method for preparing the composite oxide 1, aluminum sulfate is used in place of titanyl sulfate,
Zirconium oxychloride is used instead of colloidal silica aqueous solution or colloidal silica in a weight ratio of Al ₂ O
₃ : SiO ₂ = 10: 90, Al ₂ O ₃ : ZrO ₂ = 9
Al ₂ O ₃ .SiO ₂ composite oxide, Al ₂ O _3.
A ZrO ₂ composite oxide was obtained. This composite oxide is referred to as composite oxides 4 and 5. Using the composite oxides 2 to 5, the honeycomb was formed by the same preparation method as the honeycomb catalyst 14 to obtain honeycomb catalysts 15 to 18.

Comparative Example 1 A honeycomb catalyst was prepared in the same manner as in Example 1 except that barium sulfate was not added in the method for preparing the honeycomb catalyst 1 of Example 1. This catalyst is referred to as “honeycomb comparative catalyst 1”.

(Example 3) A hydrolysis reaction of carbonyl sulfide was carried out using honeycomb catalysts 1 to 18 and comparative catalyst 1. The test conditions are described below.

[Table 1] The COS conversion was determined by the following equation. COS conversion rate (%) = (1-outlet COS concentration / inlet CO
S concentration) x 100

Table 2 shows the results of activity evaluation (evaluated by COS conversion rate). From these results, it was confirmed that all of the developed honeycomb catalysts 1 to 18 had higher performance than the honeycomb comparative catalyst 1 in each temperature range.

[Table 2]

(Example 4) Since a large amount of hydrochloric acid coexists in the coal gasification gas, the hydrochloric acid resistance of the developed honeycomb catalyst was evaluated. The newly developed honeycomb catalyst (1, 2, 4, 5, 1
Hydrochloric acid gas (hydrochloric acid 3000 ppm / nitrogen base, 300 ° C.) was supplied to (4, 15), and after the supply, the activity was evaluated under the COS hydrolysis test conditions shown in Example 3 to examine changes in activity. The activity evaluation results are shown in Table 3.

[Table 3] It was confirmed that the catalyst developed according to the present invention was excellent in hydrochloric acid resistance and had stable activity.

[0019]

As described above, by using the developed catalyst, carbonyl sulfide, which is difficult to remove, can be easily converted to hydrogen sulfide, and the process for removing sulfur compounds in gas is greatly simplified. This is now possible.

Claims (4)

[Claims] 1. A catalyst for hydrolyzing carbonyl sulfide, wherein an anatase type titanium is added and supported as a cocatalyst with a metal sulfate or a metal carbonate. 2. The metal sulphate as a co-catalyst is selected from the group consisting of barium sulphate, calcium sulphate and magnesium sulphate, and the metal carbonate is calcium carbonate,
3. The carbonyl sulfide according to claim 1, wherein the carbonyl sulfide is selected from the group consisting of magnesium carbonate, strontium carbonate, barium carbonate, cobalt carbonate, zinc carbonate, iron carbonate, copper carbonate, nickel carbonate and manganese carbonate. Hydrolysis catalyst. 3. TiO ₂ .SiO ₂ , TiO ₂ .Al ₂
A catalyst for hydrolyzing carbonyl sulfide, comprising a composite oxide of the group consisting of O ₃ , TiO ₂ .ZrO ₂ , ZrO ₂ .Al ₂ O ₃ , and SiO ₂ .Al ₂ O ₃ . 4. A method for hydrolyzing carbonyl sulfide, which comprises hydrolyzing carbonyl sulfide in the presence of water in the presence of a reducing gas in the presence of a catalyst according to any one of claims 1 to 4.