Method of making molded vanadium-titanium catalyst for purification of gases

 

(57) Abstract:

Usage: the production of elementary sulphur by the method Claus, the oxidation of hydrogen sulfide by molecular oxygen, hydrolysis of oxysulphide and selective reduction of nitric oxide by ammonia or hydrogen sulfide. The inventive mixing titanium dioxide with a binder and a powder or a vanadium salt solution are simultaneously molded, dried at room temperature, and calcined at 450 To 500C, the process is conducted in the following ratio of components, wt: vanadium pentoxide 5 20; binder 2 80; titanium dioxide - the rest. As a binder used calcium sulfate and/or aluminium or a mixture of the sulphates of calcium and magnesium, the above binder receive the in situ interaction of compounds of calcium and magnesium, or aluminum, or calcium and aluminium with the stoichiometric quantity of sulfuric acid. As a binder used aluminum hydroxide with subsequent sulfation calcined catalyst in the apparatus Claus in the presence of oxygen-containing mixture at 250 to 450C or construction gypsum, or calcium sulfate is obtained in the form of waste, for example, in the manufacture of pentaerythritol by neutralizing the sulfonic acids with lime milk, and shall indicate in situ sulphate adding a stoichiometric amount of sulfuric acid, or a mixture of gypsum and nehalennia lime, which gives the calcium sulfate by adding stoichiometric amount of sulfuric acid. Titanium dioxide is used in the form of anatase structure or hydrated forms of titanium dioxide, which gives by heat treatment of Anitas or titanium dioxide, obtained by vapor-phase hydrolysis of titanium tetrachloride or by hydrolysis alkoxyamine of titanium compounds, or thermohydrolysis products hydrometallurgical production of titanium tetrachloride and vanadium oxide or calcined at 111 500C, titanium dioxide, or pre-frozen in the interval (5 To 60C) hydrated titanium dioxide. 10 C. p. F.-ly, 3 tables.

The invention relates to a method for preparing a stable and mechanically strong molded catalysts based on oxides of vanadium and titanium. The catalysts can be used for gas purification, namely to obtain elemental sulfur according to the method Claus, of hydrogen sulfide oxidation by molecular oxygen, as well as for hydrolysis of oxysulphide and selective reduction of nitric oxide by ammonia or hydrogen sulfide.

A review of the scientific and patent literature, known on the active and unstable at high oxygen content in the gas mixture ( 2%) due to progressive sulfate crystallization.

Catalysts based on vanadium oxide with additions of bismuth, copper, or with the prior superorganism media are more stable and active in the specified process.

The most effective and stable oxygen catalysts for Claus process are catalytic systems on the basis of the oxides of titanium and vanadium, with the possible addition of antimony.

The most common method of obtaining a molded vanadium-titanium catalyst is a method of pre-forming of titanium dioxide with subsequent impregnation with salts of vanadium. It is known that obtaining a molded titanium dioxide in its pure form is difficult and in forming TiO2often use the add as a binder metatitanate acid, silica gel, high molecular weight substances, sulfates of alkaline earth metals.

There are ways to increase the durability of the pellets TiO2due to the preliminary application in the form of a suspension or solution of molded ceramic, metal and other media, followed by drying, calcination and impregnation of the second component. A method of obtaining vanadium-titanium-antimony catalysts Claus UB>3SiO2active components or impregnated molded mass of some active ingredients in an aqueous solution of another component, or mixture of active ingredients and the carrier with the subsequent formation [1]

The disadvantage of this method of preparation are high interdiffuse braking in the grain contact, leading to a substantial decrease in activity due to a sharp decrease in the degree of use of the surface in the transition to large grains of the catalyst, as well as insufficient mechanical strength of the calcined catalyst.

The activity of sulfur in the Claus reaction, to understand the degree of conversion of hydrogen sulfide into elemental sulfur (XS,), related to the equilibrium degree of conversion, calculated for the same conditions (XS%). Sample containing 9,95% V2O540% of TiO250% SiO20,05% Sb2O4obtained by mixing powders of titanium dioxide, silica, antimony oxide and sulphate of vanadyl with the subsequent formation, the crop has wilted, drying and calcining step up to 450aboutWith, has a crushing strength by forming Pabout9,2 kg/cm2when the diameter of the shank 4 mm In total ode from grain 1 0.5 mm to 3 mm grain from 97 to 38% Test activity conducted at 250aboutC, flow rate 72000 h-1and the composition of the reaction mixture, about. H2S 2; SO21; O21; H2O 20, the rest is helium. In these conditions, the catalyst according to the proposed method had on the corn 3 mm activity, component 74,5%

Known method of preparing molded vanadium-titanium catalyst to obtain elemental sulfur and hydrogen sulfide-containing gases in the presence of oxygen [2] consisting of a mixture of titanium dioxide in the form of a gel or xerogel with a solution of oxalate vanadyl with spray drying and subsequent mixing with a solution of polyethylene oxide and a binder consisting of Zola SiO2and solution of oxalate vanadyl. The ratio of Si and V in the spanning 6 is a 2.9. Obtained in the mixer pasta molded, dried and calcined at 450 500aboutC. Method of preparation of catalysts can increase the activity of the catalyst in the diffusion region, however, has several significant disadvantages.

The main significant drawback of this method is the low mechanical strength of the catalyst after the calcination step in the oxygen. So, for the obtained extrusion ring diameter 15 mm, height 15 mm with a wall thickness of 3 to 4 mm, the crushing strength of posoboe [2] in order to avoid cracking of the pellets. The second significant drawback of this method is not sufficiently high activity of the catalyst, as a binder SiO2and a portion of the catalyst surface, has no catalytic activity in the specified process. In addition, complicated technology that requires special stages of the preparation of silica gel, polyethylene oxide, and joint spray drying of a solution of VOC2O4and hydrated titanium dioxide.

Closest to the proposed method for preparing a vanadium-titanium catalyst is a method [3] in which the catalysts are used for gas purification, namely for complete oxidation of hydrogen sulfide, sulfur and/or organic sulfur compounds in the exhaust gas of the Claus process to sulfur dioxide.

The catalysts contain:

1) titanium dioxide or a mixture of oxides of silicon and zirconium;

2) one sulfate of the alkaline earth metals;

3) at least one of the following elements or their oxides: Cu, Ag, Zn, Cd, Y, the lanthanides, V, Cr, Mo, W, Ni, Mn, Fe, Co, Rh, Ir, Pd, Pt, Sn, Bi.

The content of titanium oxide or mixtures thereof with SiO2or ZrO2is within 60 to 99% and the content of the sulfate of alkaline earth metal (predpochtitelnye active elements to elements in the media, i.e., Ti or (Ti + Si), or K (Ti + Zr) is from 5 to 10-5to 0.1, i.e., in the case of vanadium-titanium catalysts in the calculation of the V2O5in the finished catalyst is limited by the limits of 0.003 to 10.6 wt.

The catalyst of the prototype can be prepared in one of the following ways.

Method 1. Shaped element on the basis of TiO2obtained from a powder laboritories and/or amorphous TiO2with the addition of formative components, is subjected to drying and calcination in the range of 300 to 900aboutC. Then shaped element sequentially impregnated with aqueous solutions of substances containing sulfate ion, and solutions of substances containing alkaline earth cation, so that the inside of the shaped element in situ formed sulfate of alkaline earth metal. As substances containing SO4-2ion, using, for example, ammonium sulfate, hydroxylamine sulphate, sulphuric acid. Compounds that contribute alkaline earth cations, are water-soluble salts, such as nitrates, chlorides, acetates. After drying and calcining should new be impregnated with catalytically active element, for example, aqueous solution of NH4VO3with the new drying and calcining at 300 900aboutC.

4VO3), again dried and calcined. Compounds that contribute alkaline earth cations are the same as in method 1, i.e., are water-soluble salts, such as nitrates, acetates, chlorides. The same applies to compounds of the sources of sulfate anion.

Method 3. Use titanium dioxide, sulfuric acid obtained by the opening of the containing ilmenite and after hydrolysis, filtration and drying of the sulfate anion in the form of H2SO4, titanium sulfate or titanyl and basic salts. In this way it is possible or molding of titanium dioxide with sequential impregnation solutions containing alkaline earth element and vanadium, or a mixture with alkaline earth element, molding, drying, calcination and impregnation compound of vanadium by drying and calcining.

Method 4. The preparation of the catalyst according to the prototype consists in molding paste mixed composition containing TiO2and alkaline earth element, with subsequent drying and sulfation in the gas mixture SO2and O2at 250 550about4VO3), followed by drying and calcining.

The method for preparing a vanadium-titanium catalysts prototype has a number of disadvantages. The most significant disadvantage is the low activity of the resulting catalyst in the Claus reaction. So, at a temperature of 250aboutC and flow rate 72000 h-1the grain diameter of 3 mm, the degree of transformation of H2S to sulfur accounted for 62.4 per cent compared with the activity on the best catalyst of the proposed method, equal 76,0% of the composition of the initial mixture in mapping conditions included, about. H2S 2; SO21; O21, H2O 20, the rest is helium. The catalysts are less active in the recovery reactions of nitric oxide with ammonia and hydrogen sulfide than the catalysts according to the proposed method. So, at a temperature of 250aboutC, flow rate 36000 h-1and the composition of the initial mixture of 0.24% NO, 0,33% NH3, 2% O2the rest helium, the degree of conversion of nitric oxide to nitrogen on the catalyst prototype is 52,8% against 64% for the catalyst of the invention. At a temperature of 250aboutC, flow rate 650000 h-1and the composition of the initial mixture, about. NO 0,3; H2S 0,5; SO20,2; the rest is helium, the degree of conversion of nitric oxide to nitrogen and served method, respectively.

The catalyst according to the method of the prototype 10% V2O59,45% CaSO480,55% TiO2was prepared according to example 12 [3] the Paste of hydrated titanium dioxide (metatitanate acid), sulfuric acid obtained by the opening of ilmenite, contained a sulfate ion in relation to the TiO2equal to 0.08. The paste was mixed with an aqueous solution of calcium nitrate in the ratio of Ca/Ti 0,033 (example 5 prototype). After drying at 150aboutThe powder is mixed with water and molded by extrusion cuttings with a diameter of 4 mm, which are dried at 110aboutC and calcined at 400aboutC. the resulting sample contains at this stage of the preparation of 10.5 wt. aSO4and has a crushing strength by forming 14,0 kg/cm2and a specific surface area of 110 m2/so Next sample according to example 12 of the prototype, is impregnated with the aqueous solution of NH4VO3per 10% V2O5in the finished product, dried 12 h at 110aboutWith and calcined 4 h at 450aboutC. lower the catalyst activity for the prototype than for the proposed method appears to be associated with a low degree of use of surface and inhomogeneous distribution of the active component by impregnation with a solution of NH4VO3compared to the proposed sposobu is a partial cracking of the extrudate in the process of impregnation with a solution of NH4VO3and low mechanical strength obtained by the prototype of the catalyst as compared with the catalyst according to the method of the invention. Thus, the durability of the catalyst of the prototype was to handle 12 kg/cm2when the extrudate 4 mm and 20 kg/cm2when the extrudate 3 mm against maximum strength of 75 kg/cm2at best (for strength) of the catalyst of the invention, when the diameter of the extrudate 4 mm Ring catalyst with a diameter of 15 mm and a height of 15 mm and a wall thickness of 3 to 4 mm according to the method of the prototype cannot be obtained because of low strength. The crushing strength along the specified ring according to the method of the invention is from 5 to 14 kg/cm2.

The third important disadvantage of this method is the difficulty, complexity and power consumption, since all variants of the method require two - or even threefold drying and calcination of the samples, whereas the proposed method of preparation includes only the single stages of wilting, i.e., drying at room temperature, and calcination.

Fourth, a significant shortcoming of the prototype method is the possible presence in the exhaust gases during the drying and calcination of samples toxic products such as nitrogen oxides in iunii chlorides of alkaline earth metals. To create a waste-free technologies on the basis of the method of the prototype required the development of additional methods of purification of exhaust gases, which increases the cost of the technology.

Thus, the known methods for the preparation of vanadium-titanium molded catalysts do not allow to provide simultaneously high activity in the Claus process occurring in the presence of oxygen, and high strength shaped elements after calcination, i.e., do not provide a high quality product. Low mechanical strength and high hydraulic resistance of the catalyst layer, in the form of cuttings or bulbs, complicates the use of the catalyst obtained by the method prototype in the reactor with a fixed bed.

The aim of the invention is to increase activity and mechanical strength vanadium-titanium catalysts, as well as simplification of the method of their preparation.

The catalysts obtained according to the method of the invention contain, by weight. vanadium in the calculation of the V2O55 20; binder (per CaSO4or CaSO4+ MgSO4or CaSO4+ +Al2(SO4)3or Al2(SO4)32 80; titanium dioxide else.

This goal has reached the aqueous and dried powder of titanium dioxide, including hydrated, powder, suspension or aqueous solution of the binder with the addition of powder or aqueous solution of salts of vanadium and the subsequent formation in cuttings, rings, blocks, and other shaped elements, drying at room temperature and calcining in a stream of air at 450 500aboutC for 2 to 4 h with the formation of stable and active vanadium-titanium compounds.

As a binder can be used:

1) powder calcium sulfate, including construction gypsum, as well as powder or aqueous solution of any calcium compounds with a stoichiometric amount of sulfuric acid required for the formation of calcium sulfate;

2) a mixture of a powder of calcium sulfate or gypsum powder or aqueous solution of other calcium compounds with a stoichiometric amount of H2SO4necessary for the formation of these compounds calcium sulphate;

3) a mixture of gypsum and quicklime, which gives calcium sulfate when adding a stoichiometric amount of sulfuric acid;

4) waste of the production of pentaerythritol, which is a product of neutralization of the sulphonic acids with lime milk;

any compounds of calcium and magnesium with the stoichiometric quantity of sulfuric acid, necessary for the formation of sulphates of calcium and magnesium, respectively;

6) aluminum sulphate powder, and the powder or an aqueous solution of any aluminum compounds with a stoichiometric amount of sulfuric acid required to form aluminum sulphate;

7) a mixture of powders of calcium sulfate and aluminum sulfate, and a mixture of powders or aqueous solutions of any of the compounds of calcium or aluminum with a stoichiometric quantity of sulfuric acid required for the formation of calcium sulfate and aluminum sulfate, respectively;

8) aluminum hydroxide, sulfation, which occurs when mixing with compounds of titanium and vanadium, molding, drying and calcining through the reaction mixture, typical Claus process, but additionally containing oxygen at temperatures of 250 to 450aboutC. for Example, Solfatara mixture may contain about. H2S 2; SO21; O21; H2O 20 and the rest nitrogen.

Under gidratirovannym titanium dioxide hereinafter mean compounds with the General formula Ti(OH)yOxwhere x + y/2 2, including ortho - and metatitanate acid.

The main characteristics of the catalysts, prigotovlenn is the Claus reaction and the oxidation of hydrogen sulfide by molecular oxygen, activity oxysulphide in the hydrolysis of COS and the activity in the reaction of selective reduction of nitric oxide by ammonia or hydrogen sulfide. The duration of the catalysts was 24 hours are Given in table. 1 the values of the activity and selectivity of sulfur represent the observed values for the equilibrium. For all of the catalysts was determined mechanical strength cuttings, rings or blocks to crushing along generatrix (Pokg/cm2). The measurements were carried out on the instrument PPS-3.

The essence of this method of preparing vanadium-titanium catalyst is as follows. Suspension, paste or powder of titanium dioxide, including hydrated produced by liquid-phase or vapor-phase hydrolysis of TiCl4by hydrolysis alkoxylated type connection TiCl4-n(OR)nwhere n is 0-4, alkyl radical, by means of sulphuric opening of ilmenite, as well as by thermal hydrolysis of such waste vanadium production such as raffinate or secondary distillate. Before drying the slurry of hydrated titanium dioxide can be frozen at temperatures in the range of (5 to 60)aboutC. titanium Dioxide su is th moisture content. Possible heat treatment of titanium dioxide in the range of 111 500aboutC. calcium Sulfate, building plaster, waste of the production of pentaerythritol, and a mixture of the sulphates of calcium and magnesium or calcium, and aluminum or aluminum sulfate, or insoluble compounds of these metals (oxides, hydroxides), dried if necessary, at a temperature of 110 200aboutFrom and after grinding in a ball or disk mill is mixed with titanium dioxide in a kneading machine for 30 minutes Then kneading machine gradually added under stirring a powder or an aqueous solution of salt of vanadium (for example, VOSO4, VOC2O4). If necessary, the introduction of sulfate ion in an aqueous solution of salts of vanadium add sulfuric acid in stoichiometric amounts to form sulfates of calcium, magnesium or aluminum, respectively. In the case of water-soluble compounds of calcium, magnesium or aluminum (such as nitrates, chlorides, acetates) titanium dioxide in the kneading machine is mixed with an aqueous solution of the corresponding salt, and the stoichiometric quantity of sulfuric acid required to form the corresponding sulfate. If necessary, the mixture is dried and mixed in a kneading machine with a water solution is e Supplement, such as, for example, polyethylene oxide, cellulose. The resulting mixture was continued to stir for 10 to 30 minutes, and then formed into pellets with a diameter of 4 mm, ring diameter and a height of 15 to 13 mm with a wall thickness of 3 to 4 mm or in the form of other elements. The formed elements provalivajut at room temperature for 10 to 15 h, and then calcined in a stream of air in a muffle furnace for 2 4 h at 450 500aboutC. Selection as a binder calcium sulphate, a mixture of sulfates of magnesium and calcium or aluminum sulfate or a mixture of the sulphates of calcium and aluminum due to their chemical and thermal stability under the conditions of catalysis, inertness and low coefficient of linear expansion, which simplifies the technology of preparation, allowing ignited the air dry samples immediately at 450 500aboutC.

The binder content in the calcined catalyst may vary within wide limits from 2 to 80 wt. as shown in the examples. A lower binder content leads to loss of strength of the formed elements, while a higher binder content leads to the loss of the ability of the catalyst to effectively hydrolyze the oxysulphide. Selects the content of the active component V2O5in the catalyst. the usage of the content of V2O5more than 20 wt. irrational due to the appreciation of the catalyst. The choice of sulfation temperature of the catalyst in the reaction mixture (250 450about(C) when used as a binder of aluminum hydroxide is determined by the maximum speed of this process in these conditions, as well as the possibility of sulfation directly in the apparatus Claus in the presence of O2in process conditions. The minimum temperature calcination of titanium dioxide is limited by the drying temperature of 110aboutS, and the maximum resistance of the titanium dioxide to the transition of anatase to rutile. It is shown that the presence of 10 wt. rutile mixed with anatase in vanadium-titanium catalyst leads to a rapid loss of activity in the Claus reaction. So, if 250aboutWith in the mix, vol. H2S 2; SO21; O21; H2O 20; the rest is helium, for 12 h activity decline from 37 to 27% of pre-freezing Temperature of hydrated titanium dioxide determined by the actual conditions of winter transportation and storage of the paste. It is known that when peregorazhivanie hydrated titanium dioxide irreversible changes hydroxyl coverage, as well as udaleniya catalysts according to the method of [2] pre-freezing paste of titanium dioxide to (5 of 60)aboutWith results in fragile extrudate, scattered on the stage of drying. In a method prototype [3] using previously subjected to freezing paste of titanium dioxide leads to a significant decrease in strength of the final product up to 8 to 10 kg/cm2.

Thus, the important features of the proposed method from the prototype are:

a) use of the method of preparing a vanadium-titanium catalysts, consisting in the simultaneous mixing the components using as a binder calcium sulphate, a mixture of sulfates of calcium and magnesium, aluminum sulfate or a mixture of the sulphates of calcium and aluminum, entered directly or formed in situ;

b) preparation of catalysts in a wide range of concentrations of the components (5 of 20 wt. V2O5, 2 to 80 wt. binder, the rest is titanium dioxide), using the minimum number of stages: mixing, molding, drying, calcination;

C) use as raw materials of hydrated titanium dioxide, pre-frozen at a temperature (5 to 60)aboutWith or calcined in the range of 111 500aboutC;

d) sulfation of the catalyst directly in approachesto binder of aluminum hydroxide.

The production of elementary sulphur by oxidation of hydrogen sulfide with sulfur dioxide, oxygen, or their mixture is carried out in temperature-controlled flow-through installation with a fixed bed of catalyst at atmospheric pressure in the temperature range of 200 350aboutC. Similarly conducted testing of the catalyst in the hydrolysis CS simultaneous presence in a mixture of H2S, H2O, O2, CO2. In the tests varied the composition of the mixture, bulk velocity and temperature. The composition of the source and destination of the mixture was monitored by gas chromatography. Comparison of catalysts prepared by the proposed method with the catalyst according to the method prototype was performed in the same conditions.

The degree of conversion of sulfur compounds into elemental sulfur (XS) was determined by the formula:

Xs100% where CcosoC, C initial andcostoC, C finite volume concentration of these gases.

The degree of transformation of therookie carbon (Xos) by the reaction of hydrolysis was determined by the formula:

Xcos100% Degree of conversion of hydrogen sulfide in the presence of cos was calculated by the formula:

X 100% and the selectivity for the sulfur was determined by the relation

Cs100%

Restore oxide ammonia in oxygen-containing mixtures or hydrogen sulfide in the presence of sulfur dioxide was performed in a durable glass reactor with an inner diameter of 6 mm and a fixed layer of vanadium-titanium catalyst at atmospheric pressure and a temperature of 250aboutC. the Composition of the initial and the final mixture was analyzed by gas chromatography. All gas feeding system was thermostated at 130aboutC.

The degree of conversion of nitrogen oxide in a reduction reaction of ammonia was determined by the formula:

XNOwhere C is the final concentration of NH3in the experiment with a mixture containing NH3and O2; C final concentration of NH3in the experiment with a mixture containing NH3, NO, and O2. Concentrations of NH3and O2in both experiments the same. WITHNOothe initial NO concentration, about.

The degree of conversion of nitric oxide and hydrogen sulfide in the sulfur reduction reaction of NO with hydrogen sulfide were determined respectively according to the formula:

XNO100%

X= 100% where CNOoC starting WITHNOtoC final concentration of NO and H2S, respectively.

The essence of izaberete the spine of sulphur and activity by hydrolysis oS for catalysts, prepared according to the method prototype and the proposed method. Mapping activity in the processes Claus and oxidation of hydrogen sulfide with oxygen and a mixture of SO2and O2spent catalyst grain 3 mm at a flow rate of the mixture 72000 h-1. Mapping in the conditions of hydrolysis CS carried out on the catalyst grain 3 mm at a flow rate of 3600 h-1.

In table. 2 in the same conditions associated with the activity of vanadium-titanium catalysts prepared according to the prototype method and the proposed method in the reduction reaction of nitrogen oxide with ammonia in the presence of oxygen, sulfur dioxide and water vapor. The volumetric rate of the reaction mixture was 360000 h-1when the grain size of the catalyst is 0.5 to 0.25 mm

In table. 3 also in the same conditions associated with the activity of vanadium-titanium catalyst obtained by the method of the invention and the method prototype in the reduction reaction of nitric oxide with hydrogen sulfide. The volumetric rate in these experiments was 650000 h-1when the grain size of the catalyst is 0.5 to 0.25 mm

P R I m e R 1. To prepare 100 g of a catalyst consisting of 5% V2O5; 30% CaSO4and 65% of TiO2take 159,6 g paste metatitanate 60% Paste is dried at a temperature of 110aboutWith a spray drier, "Anhydro". The moisture content of the paste and powder determine soaking the sample in a drying Cabinet at 110aboutC for 12 hours To the resulting powder in a kneading machine, add 30 g of calcium sulfate produced as a waste of pentaerythritol by neutralizing the sulfonic acids with a solution of calcium hydroxide and dried at 140 to 160aboutC. In the kneading machine add 5,97 g of sulfate of vanadyl VOSO43H2O mark H. D. and. and components of the mixture stirred for 30 min, then added 58 ml of distilled water and continue to mix for another 15 minutes the resulting paste is transferred into a metal syringe and molded cuttings with a diameter of 4 mm, the Extrudate is dried at room temperature to air-dry for 12 to 15 hours and calcined in the muffle in a stream of air at 450 500aboutC for 2 h

As shown in the table. 1, the resulting catalyst has a higher crushing strength along generatrix (24,5 kg/cm2and activity in the Claus reaction in the presence of water vapor in complex mode (2% H2S, 1% SO2, 1% O2, 20% H2O, the rest is helium) than the catalyst according to the method prototype.

P R I m m e R 2. To prepare 100 g of the catalyst SOS is/SUB>) obtained by hydrolysis of titanium tetrachloride at pH 7 and a temperature of 70aboutIn the presence of NH4OH and dried after filtration at 110aboutC. titanium Dioxide are mixed in a kneading machine with 1.1 g of calcium hydroxide mark H. D. and mix powders for 30 min, then gradually add the water solution containing 1.45 g of concentrated sulfuric acid (calculated on anhydrous) and 34 g of the oxalate vanadyl. The oxalate vanadyl get interaction 20 g of vanadium pentoxide mark "h" with a water solution containing 41,6 g H2C2O42H2O mark "h", when the 40aboutC. After stirring for 15 20 min pasta shaped in the form of cuttings with a diameter of 4 mm, provalivajut in the air and 4 hours and calcined at 450 500aboutC. In the table. 1 shows that the calcined sample has a strength of 15.0 kg/cm2and activity in the oxidation of hydrogen sulphide and mixed mode is superior to the catalyst of the prototype.

P R I m e R 3. To prepare 100 g of the catalyst composition of 10% V2O580% of CaSO410% of TiO contribute in a kneading machine 80 g calcium sulfate brands including D. A. after proper drying and 12.3 g of hydrated titanium dioxide. Hydrated titanium dioxide was Paul who tion dried at 110aboutC.

Powders stirred for 30 min, and then kneading machine gradually introduce an aqueous solution containing 11,94 Mr. VOSO43H2O mark H. D. a. Continue mixing for another 15 to 20 minutes and then extrusion molded cuttings 4 mm, ring diameter of 15 mm and cell blocks of size 24 x 24 x 40 mm with a wall thickness of 3 mm. After wilting and calcining at 450 500aboutSince, as can be seen from the table. 1, the catalyst in the form of cuttings, rings and blocks has the strength of 30, 9.5 and 12 kg/cm2accordingly, the activity in the oxidation of hydrogen sulfide with oxygen in the presence of water vapor, as well as in hard mode, exceeding the activity of the catalyst of the prototype.

P R I m e R 4. Similar to examples 1 to 3. The difference is that the catalyst composition of 15% V2O5, 27% CaSO4, 3% MgSO4, 55% TiO get, using as raw materials for titanium dioxide product vapor-phase hydrolysis of TiCl4at 450aboutC. as a binder used in the mixture of powdered oxides of magnesium and calcium in a mass ratio of 1 11. After mixing the powders for 30 min in a kneading machine contribute gradually aqueous solution containing 16,06 g of the oxalate vanadyl and 21.8 g H2SO4(calculated as anhydrous). To kneading machinetalker has a maximum strength in the range of catalysts for the proposed method, component 75 kg/cm2. The activity of this catalyst in the Claus reaction, the complex mode and the hydrolysis of therookie carbon exceeds the activity of the catalyst of the prototype.

P R I m e R 5. The catalyst composition of 15% V2O530% of the CaSO4, 55% of TiO2get analogously to example 1. The difference is in the use as a binder gypsum brand G-6. As a solution of the active component in a kneading machine make a solution of oxalate vanadyl obtained according to example 2 containing 0.2% of a polyethylene oxide calculated on the total weight of the mixture. The finished catalyst has a strength of 27 kg/cm2and activity in mixed mode, exceeding the activity of the catalyst of the prototype.

P R I m e R 6. To prepare 100 g of the catalyst composition of 15% V2O55% of Al2(SO4)3, 80% TiO take 98 g metatitanate acid, sulfuric acid obtained by the opening of ilmenite and pre-dried at 110about(See example 1). As a binder in a kneading machine introduced 5 g of aluminium sulphate brands including D. A. calculated on the anhydrous and after stirring for 30 min, gradually pour in water solution containing 25,5 g VOC2O4. The way to obtain the oxalate water, as can be seen from example 6, PL. 1, has a high strength of 37 kg/cm2and activity in mixed mode (250aboutC, 2% H2S, 1% SO2, 1% O2, 20% H2O) exceeding the activity of the catalyst of the prototype.

P R I m e R 7. Obtaining a catalyst composition 10% C2O530% of Al2(SO4)360% of TiO2analogously to example 6. The difference lies in the fact that the binder used aluminium hydroxide AlOOH. After molding, wilting and calcining at 450 500aboutWith the catalyst loaded into the reactor of the Claus process and in a mixture containing 2% H2S, 1% SO2, 1% O2, 20% H2O, the rest is helium, gradually increasing the temperature from 250 to 450aboutC for 12 h, the Strength of the finished catalyst is of 37.9 kg/cm2. The activity in the complex mode is higher than the activity of the catalyst of the prototype.

P R I m e R 8. The catalyst composition of 15% V2O510% of Al2(SO4)310% of CaSO4, 65% of TiO2is obtained analogously to example 6. The difference is that as a binder make a mixture of calcium sulfate and aluminum hydroxide. Compound of vanadium sulfate of vanadyl) is injected in the form of an aqueous solution containing 8.6 g H2SO4in the calculation natica water cooling. The finished catalyst after calcination has the strength of 53 kg/cm2and superior in activity in complex mode, the catalyst of the prototype.

Below are examples of the preparation of the catalysts, the compositions of which are outside of the concentrations of the proposed method.

P R I m e R 9. The catalyst composition of 4% V2O530% of the CaSO466% of TiO2was obtained analogously to example 1. The difference was in the use of fewer sulphate vanadyl (4.8 g). As can be seen from the table. 1, a finished catalyst containing 4 wt. V2O5had lower activity in the complex mode Claus process than the catalyst of the prototype.

P R I m e R 10. The catalyst composition of 15% V2O5, 1% CaSO4, 84% of TiO2is obtained analogously to example 1. The difference lies in the use of a small amount of binding CaSO4obtained by mixing calcium hydroxide and sulfuric acid. The finished catalyst has activity in complex mode Claus process is more than the catalyst for the prototype, but the strength of the obtained catalyst is unsatisfactory.

P R I m e R 11. The catalyst composition of 15% V2O5, 81% CaSO44% of TiO2get the mixture of powders is added an aqueous solution of sulfate of vanadia. The finished catalyst after molding, wilting and calcining at 450 500aboutWith had a high strength and activity in complex mode, however, the activity of the hydrolysis reaction oS on this catalyst were lower than the catalyst of the prototype.

Below are examples of the preparation of the catalysts of the proposed method with using them in the recovery processes of nitric oxide by ammonia and hydrogen sulfide.

P R I m e R 12. The catalyst composition of 15% V2O530% of the CaSO4, 55% of TiO2obtained by blending powders previously frozen metatitanate acid, gypsum and calcium oxide in the form of quicklime with the addition of sulfuric acid. Paste metatitanate acid, sulfuric acid obtained by the opening of ilmenite, frozen at -35aboutC and maintained for 2 days. Then the paste is dried using a spray dryer "Anhydro" at 110aboutWith and in the number of 67.4 g is placed in a kneading machine. At the same time there is added 15 g of gypsum G-6 and 6,18 g quicklime and powders stirred for 30 minutes In a kneading machine add an aqueous solution containing of 25.5 g of the oxalate vanadyl and 10.8 g H2SO4calculated on the anhydrous and continue lane is rosalki at 450 500aboutWith the current air catalyst has the strength of 44 kg/cm2and activity in the recovery of nitric oxide with ammonia in the presence of oxygen, and SO2and water vapor is higher than the catalyst of the prototype (table. 2).

The mapping is carried out at a temperature of 250aboutC, flow rate of the mixture 360000 h-1at a fraction of the catalyst is 0.5 to 0.25 mm

P R I m e p 13. The catalyst composition of 15% V2O530% of the CaSO4, 55% of TiO2get analogously to example 12. The differences consist in the fact that the hydrated titanium dioxide obtained by the sulfuric acid opening of ilmenite, dried at 110aboutC and calcined at 500aboutC for 4 h as a binder a mixture of calcium sulfate (15 g) and calcium oxide with the introduction into the solution of oxalate vanadyl 10.8 g H2SO4calculated on the anhydrous. The finished catalyst has a strength of 30.6 kg/cm2and superior in activity in the reduction reaction of nitric oxide with hydrogen sulfide the catalyst prototype (PL. 3). The mapping is carried out at a temperature of 250aboutC and flow rate of the mixture 650000 h-1on the catalyst grain 0,5 0,25 mm

P R I m e R 14. The catalyst composition of 15% V2O530% of the CaSO4, 65% hydrolysis of waste hydrometallurgical production of titanium tetrachloride and vanadium oxide. Secondary distillate and a raffinate containing titanium tetrachloride are mixed in the ratio of 1 to 30 and after thermal hydrolysis, neutralization with calcium hydroxide, washing and filtration, dried at 110aboutWith in an oven for 12 hours 106 g of dried powder containing 9% nuclear calcium are mixed in a kneading machine with a water solution containing of 25.5 g of the oxalate vanadyl and 21.6 g H2SO4calculated on the anhydrous. After 15 to 20 minutes stirring the paste is formed into the form of an extrudate with a diameter of 4 mm and a tube outer diameter of 13 mm, a height of 13 mm and a thickness of 3 to 4 mm, the strength of the extrudate and tube crush strength by forming accounted for provyalennuyu and calcined at 450 500aboutC, respectively, 33 and 14 kg/cm2. The activity of the catalyst in the reduction reaction of nitrogen oxides with hydrogen sulfide exceeds the activity of the catalyst of the prototype.

As seen from the above examples, the proposed method for the preparation of molded kislorodozavisimogo vanadium-titanium catalyst containing as a binder calcium sulphate, calcium and magnesium, aluminum, or calcium, and aluminum, can significantly increase the strength and activity of sulphur and hydrolysis oS catalysts in the process of polyolene of nitric oxide by ammonia or hydrogen sulfide. In addition, the proposed method allows the preparation to obtain catalysts, which have a number of useful properties, which are achieved in the preparation of catalysts other methods, namely:

high mechanical strength of the catalysts, allowing to make the proposed method, various shaped items;

high thermal stability of the catalysts, allowing calcined catalysts immediately at 450 500aboutWith not using stepwise temperature rise;

high and stable catalytic activity in the presence of oxygen in the Claus reaction and in the presence of SO2in the reduction reaction of NO with ammonia;

high performance catalysts in diffusive communication with the optimal porous structure;

the suitability of the proposed method for preparation of the catalyst in the case of low specific surface source of titanium dioxide, especially in the case of pre-frozen or calcined to 500aboutWith varieties of raw materials;

the simplicity and efficiency of the proposed method, requiring only a single calcination of the catalyst and using such a cheap raw material, such as waste pentericci-titanium catalyst environmentally friendly method when using as vanadium raw materials oxalate vanadyl, giving when the calcining only carbon dioxide;

the suitability of the method for preparation of catalysts for different gas purification processes, such as the Claus process, the oxidation of hydrogen sulfide, CoS hydrolysis, the recovery of nitric oxide by ammonia or hydrogen sulfide.

1. METHOD of MAKING MOLDED VANADIUM-TITANIUM CATALYST FOR the PURIFICATION of GASES, including the interaction of titanium dioxide, a compound of vanadium and binding calcium sulfate or any calcium, giving sulfate when interacting with sulfuric acid in situ, drying, annealing, characterized in that, in order to obtain a catalyst with increased activity, mechanical strength and simplifying the technology, interaction perform simultaneous mixing titanium dioxide with a binder and a powder or a solution of salt of vanadium, followed by molding, drying at room temperature and calcining at 450 500oAnd the process is conducted at a ratio of components that provide the following content in the catalyst, wt.

The vanadium pentoxide 5 20

Binder 2 80

Titanium dioxide Else

2. The method according to p. 1, characterized in that the binder used calcium sulfate and/or aluminum, obtained in situ by the interaction of compounds of calcium and magnesium or aluminum, or calcium and aluminium with the stoichiometric quantity of sulfuric acid.

4. The method according to p. 1, characterized in that the binder used aluminum hydroxide with subsequent sulfation calcined catalyst in the apparatus Claus in the presence of oxygen-containing mixture at 250 450oC.

5. The method according to p. 1, characterized in that the binder used construction gypsum or calcium sulphate obtained in the form of waste, for example, in the manufacture of pentaerythritol by neutralizing the sulfonic acids with lime milk.

6. The method according to PP. 1 to 3, characterized in that the binder is a mixture of the corresponding sulphate compounds of calcium or calcium and magnesium, or aluminum, or calcium and aluminum, which provide in situ sulphate adding a stoichiometric amount of sulfuric acid.

7. The method according to p. 1, characterized in that as a binder a mixture of gypsum and quicklime, which gives the calcium sulfate by adding stoichiometric amount of sulfuric acid.

8. The method according to PP. 1 to 7, characterized in that use is ode anatase.

9. The method according to p. 8, characterized in that the titanium dioxide receive a vapor-phase hydrolysis of titanium tetrachloride, or by hydrolysis alkoxyamine of titanium compounds, or thermohydrolysis products hydrometallurgical production of titanium tetrachloride and vanadium oxide.

10. The method according to PP. 1 to 8, characterized in that use calcined at 111 500oWith titanium dioxide.

11. The method according to PP. 1 to 8, characterized in that use pre-frozen in the range of 5 to 60oWith hydrated titanium dioxide.

 

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