CN1768928A - Sulfur-containing gas catalytic incineration catalyst, preparation method and application - Google Patents

Abstract

The invention discloses a sulfur-bearing gas burning catalyst and its preparation process, wherein the catalyst carrier is silicon dioxde, the active component is the oxide compound of vanadium and titanium. Calculated by weight ratio of the catalyst, the content of silicon dioxide 65-95%, the content of vanadium oxide is 0.5-15%, the content of titanium oxide is 0.5-20%.

Description

Sulfur-containing gas catalytic incineration catalyst, preparation method and application

technical field

The invention relates to a sulfur-containing gas incineration catalyst and its preparation method and application. It is suitable for the treatment of waste gas containing various compounds such as hydrogen sulfide, carbon disulfide and carbonyl sulfide, and can convert the above-mentioned sulfides into sulfur dioxide with low odor and toxicity. It is especially suitable for catalytic incineration treatment of sulfur recovery Claus process tail gas and geothermal power plant waste gas.

Background technique

Hydrogen sulfide and organic sulfides (such as carbon disulfide, carbonyl sulfide) are a class of odorous pollutants with varying degrees of toxicity to the human body, mainly from industrial exhaust gases such as oil refining, natural gas, chemical industry, sewage treatment, and geothermal power generation. Taking the refinery as an example, the sulfur recovery tail gas contains a certain amount of hydrogen sulfide and organic sulfide. In order to meet the emission standards of odor pollutants, it must be incinerated before it can be discharged. Since the combustible components in the tail gas (such as hydrogen sulfide, carbonyl sulfide, carbon monoxide, carbon disulfide, hydrogen, elemental sulfur and a small amount of oil and gas) are often less than 3% of the total tail gas, fuel must be supplemented to completely burn and oxidize the sulfide for sulfur dioxide. There are two types of tail gas incineration processes: thermal incineration and catalytic incineration. The thermal incineration method is usually carried out with excess oxygen and 700-820°C. Because it is difficult to precisely control the operating conditions such as incineration temperature, in practice, the incinerator is often deformed, which reduces the service life of the incinerator. Under the action of a catalyst, catalytic incineration can oxidize hydrogen sulfide, carbon disulfide and carbonyl sulfide in the tail gas to sulfur dioxide at a relatively low temperature (such as 300-400 ° C). The investment of catalytic incineration is about 10% higher than that of thermal incineration, and energy consumption and operating costs can be saved by nearly 50%. The actual benefit of catalytic incineration is related to the scale of the device. A 100t/d sulfur recovery device can save 1000m ³ /d of gas, and the fuel cost saved during the service life of the catalyst is more than 10 times the cost of the catalyst consumed. Therefore, catalytic incineration can meet the needs of environmental protection and energy saving at the same time.

Catalyst is an important part of sulfur-containing gas catalytic incineration technology. The key to the performance of this type of catalyst is how to overcome the sulfation of the active center of the catalyst and maintain the stability and activity of the catalyst for long-term operation. CN1049299A discloses a sulfur-containing organic waste gas incineration catalyst and its preparation method. The catalyst uses natural mordenite modified by sulfuric acid treatment as the _carrier , _V2O5 as the main active component, and a small amount of precious metals such as platinum and palladium as the auxiliary activity Components, the content of V ₂ O ₅ is 0.4% to 0.7% (mass percentage, the same below), the content of platinum is 0.01% to 0.02%, the content of palladium is 0.02% to 0.03%, and it can also contain 0.01% to 0.07% of cobalt One or more of manganese, molybdenum, nickel, potassium, and sodium oxides. When the reaction temperature is 320-380°C, the space velocity is 4800-10000h ^-1 , and the organic sulfur concentration is 800-10000 mg/l, the conversion rate is ≥99%. This kind of catalyst supports noble metals, which has high cost and limited resistance to sulfur poisoning. CN1410149A discloses a catalyst for incineration of hydrogen sulfide in gas and its preparation and use method. The carrier of the catalyst is silicon oxide, and the active components are oxides of iron and vanadium. The invention is applicable to hydrogen sulfide, the oxidation activity of organic sulfur is unknown.

CN1163785A discloses a catalytic incineration process of hydrogen sulfide in gas, which is suitable for treating Claus tail gas, uses activated carbon as a catalyst, and catalyzes the oxidation of hydrogen sulfide to sulfur dioxide at a temperature of 200-400°C. The content of hydrogen sulfide is 0.5%-4% (v/v), the content of water vapor is 4%-30% (v/v), the space velocity is 3000-10000h ^-1 , the conversion rate of hydrogen sulfide is 100%, and the production rate of sulfur dioxide is 90%. ~99%. USP4576184, 4444908, 4528277, 4444741, 4444742, and 4314983 disclose a class of hydrogen sulfide oxidation catalysts and processes. The active components of the catalyst include vanadium and bismuth, and can also be composed of vanadium and tin or antimony. The carrier is a porous high-temperature-resistant oxide , consisting of one or more of alumina, silica-alumina, silica, titania, zirconia, silica-titania, silica-zirconia, silica-zirconia-titania , can oxidize hydrogen sulfide to sulfur or sulfur dioxide, and is characterized by high activity and stability in the presence of water vapor. For example, for a catalyst with an active component of 11.6% Bi ₂ O ₃ +8.6% V ₂ O ₅ , at a reaction temperature of 240°C and a space velocity of 2000h ^-1 , 2717ppm of hydrogen sulfide is completely converted into sulfur dioxide, and hydrogen and methane are not oxidized. USP4427576, 4937058 discloses a kind of catalyst that oxidizes hydrogen sulfide or organic sulfur into sulfur dioxide and its preparation process. The carrier of the catalyst is titanium dioxide, or a mixture of titanium dioxide and zirconia or silicon dioxide, and the active component Sulfate with at least one of the following metals: copper, silver, zinc, cadmium, yttrium, lanthanum, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, rhodium, iridium, nickel, palladium, platinum, tin, and bismuth , the content of the carrier is 60%-99%, the content of alkaline earth metal sulfate is 1%-40%, and the specific surface of the catalyst is 20-500m ² /g. The reaction temperature is 380°C, the space velocity is 1800h ^-1 , the feed gas contains 800ppm hydrogen sulfide, 100ppm carbonyl sulfide, 500ppm carbon disulfide, 400ppm sulfur dioxide, 2% oxygen, 30% water vapor, 67.82% nitrogen, and the catalytic conversion rate of hydrogen sulfide is >99% , the catalytic conversion rate of carbon disulfide is 61% to 98%, and the catalytic conversion rate of carbonyl sulfide is 52% to 94%. USP4148760 discloses a sulfur-containing compound oxidation catalyst, the carrier of which is high-alumina cement, and the active components are V ₂ O ₅ and Fe ₂ O ₃ , which may also contain titanium and silver oxides. The catalyst can oxidize hydrogen sulfide, carbonyl sulfide and carbon disulfide in the Claus tail gas into sulfur dioxide. USP4197277 discloses a sulfur-containing compound oxidation catalyst, the carrier of which is alumina, and the active components are V ₂ O ₅ and Fe ₂ O ₃ , which may also contain oxides of titanium and silver. The catalyst can oxidize hydrogen sulfide, carbonyl sulfide and carbon disulfide in the Claus tail gas into sulfur dioxide.

USP5278123 discloses a catalyst capable of oxidizing sulfur-containing compounds to sulfur dioxide, the carrier is titanium dioxide, and the active components are iron and platinum. USP6019953 discloses a gas incineration process suitable for catalytic incineration of sulfide-containing gas. The first metal component of the catalyst is bismuth, molybdenum or chromium, the second metal component is one or more of Group IIA metals, the carrier is a high temperature resistant oxide, and the carrier cannot contain aluminum and phosphorus at the same time. The complete oxidation temperature of hydrogen sulfide given in the example is 500°C. USP4169136, 4092404, 4171347, 4088743 disclose the catalytic incineration process of hydrogen sulfide in a class of gas, this process can oxidize hydrogen sulfide to sulfur dioxide, the operating temperature is 150 ~ 480 ℃, the active component of the catalyst is the oxide of vanadium and/or Or vanadium sulfide, the carrier is non-alkaline porous refractory oxide. A good catalyst is 5%-15% V ₂ O ₅ /hydrogenated mordenite or alumina. Hydrogen, carbon monoxide, light hydrocarbons and ammonia in the feed gas are not oxidized, and the patent has been used in the treatment of waste gas from geothermal power plants. USP4399112 discloses a sulfur-containing waste gas catalytic incineration process, which can be used for the treatment of Claus tail gas. The process consists of two stages. First, carbon disulfide, carbonyl sulfide, mercaptan and other sulfides are hydrogenated and reduced to hydrogen sulfide, and then Hydrogen sulfide is catalytically oxidized to sulfur dioxide, and the catalyst in the oxidation stage is iron sulfate/titanium dioxide.

Contents of the invention

The invention provides a sulfur-containing gas incineration catalyst with high activity and good stability, a preparation method thereof and an application of the catalyst.

The sulfur-containing gas incineration catalyst of the present invention uses silicon dioxide as a carrier and oxides of vanadium and titanium as active components. In terms of catalyst weight: the content of silicon dioxide is 65% to 95%, the oxide content of vanadium is 0.5% to 15%, preferably 2% to 8%, and the oxide content of titanium is 0.5% to 20%, preferably 2% to 15%. The specific surface area of the catalyst is 200-350m ² /g, and the pore volume is 0.3-0.8ml/g.

The catalyst of the invention can be used for incineration treatment of one or several sulfur-containing compounds in hydrogen sulfide, carbon disulfide and carbonyl sulfide in gas, and oxidizes the above-mentioned sulfur-containing compounds into sulfur dioxide, carbon dioxide and water.

The phase of the silica carrier is an amorphous phase, and water-resistant coarse-porous spherical silica gel can be used, with a specific surface area of 200-400m ² /g and a pore volume of 0.4-0.9ml/g. The oxide of vanadium is V ₂ O ₅ , and the oxide of titanium is TiO ₂ .

The best shape of catalyst of the present invention is 4～6mm spherical, can adopt impregnation method to prepare, has two kinds of preparation procedures, as follows:

(1) First use organic titanium compounds (such as isopropyl titanate Ti(OCH(CH ₃ ) ₂ ) ₄ , butyl titanate Ti(OC ₄ H ₉ ) ₄ , ethyl titanate Ti(OC ₂ H ₅ ) ₄ , etc.) in an organic solution (such as toluene, ethanol or isopropanol, etc.) or an ethanol solution of titanium trichloride impregnated with a silica carrier (dried at 120°C), evaporated the organic solvent to dryness in vacuo, and dried and roasted the obtained sample After that, it is impregnated with the oxalic acid solution of the water-soluble compound of vanadium, then dried and roasted, the titanium compound is decomposed into TiO ₂ by roasting, and the water-soluble compound of vanadium is decomposed into V ₂ O ₅ by roasting. The water-soluble compound of vanadium is preferably ammonium metavanadate, and the water-soluble compound of vanadium is dissolved in 1.0-2.0 mol/L oxalic acid solution. The water-soluble compound of titanium is preferably butyl titanate.

(2) First impregnate the silica carrier with an oxalic acid solution of a water-soluble compound of vanadium (such as ammonium metavanadate) (dried at 120°C), dry and roast, and then use an organic titanium compound (such as isopropyl titanate) Organic solutions of Ti(OCH(CH ₃ ) ₂ ) ₄ , butyl titanate Ti(OC ₄ H ₉ ) ₄ , ethyl titanate Ti(OC ₂ H ₅ ) _{4 ,} etc.) (such as toluene, ethanol or isopropanol etc.) or ethanol solution of titanium trichloride impregnated, the organic solvent was evaporated to dryness in vacuum, then dried and roasted. The titanium compound is decomposed into TiO ₂ after roasting, and the water-soluble compound of vanadium is decomposed into V ₂ O ₅ after roasting.

In the above preparation process, the drying temperature is generally 110-150°C, the drying time is 2-12 hours, the calcination temperature is 450-550°C, and the calcination time is 4-5 hours.

The catalyst of the invention is used for catalytic burning of sulfur-containing gas (such as hydrogen sulfide, carbon disulfide, carbonyl sulfide, etc.), and is especially suitable for catalytic burning of tail gas of Claus sulfur recovery process in oil refinery. The process is: mix sulfur-containing gas with excess air, after preheating, pass through the catalytic incinerator at a space velocity of 2000-10000h ^-1 , and at a reaction temperature of 200-400°C, hydrogen sulfide, carbon disulfide and carbonyl sulfide are catalyzed Oxidized to sulfur dioxide, carbon dioxide and water.

Due to the interaction between the various components of the catalyst, different components have different performances. The characteristics of the catalyst of the present invention are: high catalytic activity, under optimal conditions, the oxidation rate of hydrogen sulfide is higher than 99%, the oxidation rate of carbon disulfide and carbonyl sulfide is higher than 85%, and the generation rate of sulfur dioxide is higher than 96%; Long, the carrier and active components are resistant to sulfation; the operating temperature is 200-400°C, and the space velocity can reach 10000h ^-1 .

Detailed ways

Example 1

Weigh 18.4g of isopropyl titanate [Ti(OCH(CH ₃ ) ₂ ) ₄ ] and dissolve it in 100ml of toluene, soak 100g of 4-6mm water-resistant coarse-porous spherical silica gel dried at 120°C for 2 hours in it and stir evenly. Let it stand for 12 hours, then evaporate the solvent to dryness with a rotary evaporator at 60°C, dry at 120°C for 6h, and roast at 500°C in air for 4h, and then soak it with 7.1g ammonium metavanadate, 25.2g oxalic acid (C ₂ H ₂ O ₄ ·2H ₂ O) and 100ml of distilled water, after stirring at 30°C, let it stand for 12h, then evaporate the water to dryness with a rotary evaporator at 50°C, dry at 120°C for 6h, and then Calcined at 500°C for 4 hours in air to obtain catalyst samples. The composition of the catalyst is: silicon dioxide 90%, V ₂ O ₅ 5%, TiO ₂ 5%. The catalyst was evaluated on a small-scale catalytic incineration test device. The feed composition was hydrogen sulfide 1% (v/v), carbon disulfide 0.1% (v/v), carbonyl sulfide 0.1% (v/v), water vapor 30% (v/v), reaction temperature 300°C, space velocity 5000h ^-1 . The evaluation results are shown in Table 1.

Table 1 Conversion rate of sulfide and generation rate of sulfur dioxide hydrogen sulfide carbon disulfide carbonyl sulfide Conversion rate,% 100 85 88 Sulfur dioxide formation rate, % 100 96 98

Example 2

The catalyst composition is: silicon dioxide 85%, V ₂ O ₅ 5%, TiO ₂ 10%. The feed composition is hydrogen sulfide 1% (v/v), carbon disulfide 0.1% (v/v), carbonyl sulfide 0.1% (v/v), water vapor 30% (v/v). The reaction temperature is 300°C and the space velocity is 5000h ^-1 . See Table 2 for the evaluation results.

Table 2 Conversion rate of sulfide and generation rate of sulfur dioxide hydrogen sulfide carbon disulfide carbonyl sulfide Conversion rate,% 100 88 90 Sulfur dioxide formation rate, % 100 98 99

Example 3

The composition of the catalyst is: 90% of silicon dioxide, 5% of V ₂ O ₅ , and 5% of TiO ₂ . The feed composition is hydrogen sulfide 1% (v/v), carbon disulfide 0.1% (v/v), carbonyl sulfide 0.1% (v/v), water vapor 30% (v/v). The reaction temperature is 300°C and the space velocity is 10000h ^-1 . The evaluation results are shown in Table 3.

Table 3 Conversion rate of sulfide and generation rate of sulfur dioxide hydrogen sulfide carbon disulfide carbonyl sulfide Conversion rate,% 99 75 80 Sulfur dioxide formation rate, % 100 95 96

Example 4

The composition of the catalyst is: 90% of silicon dioxide, 5% of V ₂ O ₅ , and 5% of TiO ₂ . The feed composition is hydrogen sulfide 1% (v/v), carbon disulfide 0.1% (v/v), carbonyl sulfide 0.1% (v/v), water vapor 30% (v/v). The reaction temperature is 350°C and the space velocity is 5000h ^-1 . The evaluation results are shown in Table 4.

The conversion rate of table 4 sulfide and the generation rate of sulfur dioxide hydrogen sulfide carbon disulfide carbonyl sulfide Conversion rate,% 100 88 92 Sulfur dioxide formation rate, % 100 98 99

Example 5

The catalyst composition is: silicon dioxide 80%, V ₂ O ₅ 10%, TiO ₂ 10%.

Example 6

The catalyst composition is: silicon dioxide 85%, V ₂ O ₅ 10%, TiO ₂ 5%.

Example 7

The catalyst composition is: silicon dioxide 93%, V ₂ O ₅ 2%, TiO ₂ 5%.

The catalysts described in Examples 5-7 are used for catalytic incineration treatment of sulfur-containing waste gas. The feed composition is hydrogen sulfide 1% (v/v), carbon disulfide 0.1% (v/v), carbonyl sulfide 0.1% (v/v), water vapor 30% (v/v). The reaction temperature is 350°C and the space velocity is 5000h ^-1 . The evaluation results are shown in Table 5.

Table 5 Embodiment 5～7 catalyst application result Conversion rate, %/Sulfur dioxide generation rate, % hydrogen sulfide carbon disulfide carbonyl sulfide Example 5 100/100 89/99 93/99 Example 6 100/100 88/98 92/99 Example 7 99/99 83/96 85/98

comparative example

Catalyst A prepared by CN1410149A embodiment 1 was evaluated according to the evaluation method of embodiment 1 of the present invention, and the results are shown in Table 6.

Table 6 Comparative Example Catalyst Experimental Results hydrogen sulfide carbon disulfide carbonyl sulfide Conversion rate,% 100 55 70 Sulfur dioxide formation rate, % 99 85 90

Claims (10)

1, a kind of sulfurous gas catalytic incineration catalyst, it is characterized in that with silica being carrier, with vanadium and titanyl compound is active component, in catalyst weight: the content of silica is 65%～95%, the oxide content of vanadium is 0.5%～15%, and titanyl compound content is 0.5%～20%.

2, according to the described catalyst of claim 1, the oxide content that it is characterized in that described vanadium is 1%～8%, and titanyl compound content is 2%～10%.

3, according to claim 1 or 2 described catalyst, the specific area that it is characterized in that described catalyst is 200～350m ²/ g, pore volume are 0.3～0.8ml/g.

4, according to the described catalyst of claim 1, it is characterized in that described silica supports is an amorphous phase, its specific area is 200～400m ²/ g, pore volume are 0.4～0.9ml/g; The oxide of vanadium is V ₂O ₅, titanyl compound is TiO ₂

5, according to the described arbitrary Preparation of catalysts method of claim 1 to 4, it is characterized in that adopting immersion process for preparing.With the organic solution impregnation of silica carrier of titaniferous compound,, after gained sample drying, the roasting, use the oxalic acid solution dipping of the water soluble compound of vanadium again, dry then, roasting earlier with the organic solvent evaporated in vacuo.Or use the oxalic acid solution of the water soluble compound of vanadium to flood earlier, after gained sample drying, the roasting, use the organic solution impregnation of silica carrier of titaniferous compound again, with organic solvent evaporated in vacuo, roasting then.

6, in accordance with the method for claim 5, it is characterized in that the baking temperature in the catalyst preparation process is 110～150 ℃, be 2～12h drying time, and sintering temperature is 450～550 ℃, and roasting time is 4～5h.

7, in accordance with the method for claim 5, the water soluble compound that it is characterized in that described vanadium is one or more in ammonium metavanadate, vanadic sulfate, the vanadium oxalate etc.; Titanium compound is one or more in titanium trichloride, isopropyl titanate, butyl titanate, the tetraethyl titanate etc.

8, the application of the arbitrary catalyst of a kind of claim 1 to 4 in the sulfurous gas catalytic burning.

9,, it is characterized in that in described sulfurous gas sulfide hydrogen, carbon disulfide and the cos one or more according to the described application of claim 8.

10,, it is characterized in that the catalytic burning air speed is 2000～10000h according to the described application of claim 8 ^-1, temperature is 200～400 ℃.