RU2748990C1 - Catalyst, its preparation method, and process of ammonia oxidation - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a catalyst of a block cellular structure for the oxidation of ammonia to nitric oxide (II), which is a mixed oxide of the general formula (MeO)_x(Mg_2-yMp_yAl₄Si₅O₁₈)_1-x, where x=0.01-0.2, y=0.05-0.2, MeO is the active component of the catalyst, Me is Mn, Fe, Co, Ni, Cu, Cr, V and/or their mixtures, Mr is the promoter, which is a mixture of Fe, K, Na, Li, Ca, Ti, and Mg_2-yMp_yAl₄Si₅O₁₈ is the forming component of the catalyst, which has the cordierite structure. The invention also relates to a method for preparing a catalyst of a block cellular structure for the oxidation of ammonia to nitric oxide (II) and to the process of oxidation of ammonia to nitric oxide (II).

EFFECT: an increase in the activity and strength of the catalyst, an increase in the run time of the catalyst grids as part of a two-stage catalytic system.

4 cl, 2 tbl, 11 ex

Description

The invention relates to catalysts for the oxidation of ammonia to nitric oxide (II) in the production of weak nitric acid.

The main industrial catalysts for the oxidation of ammonia are currently networks of platinum and its alloys with palladium and rhodium. In the context of the high cost of platinum group metals, the task of reducing financial costs and material losses of platinoids is still urgent. Currently, this problem in industry is being solved by implementing the oxidation process on a 2-stage catalytic system, in which an incomplete set of platinoid grids is used as the first stage, and a layer of an oxide catalyst as the second stage.

Various oxide catalysts for the oxidation of ammonia are known, in which the active component is oxides of iron, chromium, cobalt, bismuth, oxides with the structure of perovskite, hexaaluminate, and others.

Known oxide catalyst obtained by mixing oxides of aluminum, iron, calcium and chromium, followed by tableting and calcination at 875-900 ° C [SU 641985, B01J37 / 04, S01B1 / 00, 15.01.1979].

Known catalyst for the oxidation of ammonia, containing 90-95 wt.% Iron oxide and 5-10 wt.% Chromium oxide, obtained by mixing iron and chromium nitrates, holding at 315 ° C, cooling, mixing with graphite, followed by tableting and calcining at 560- 650 ° C [FR 2119121, B01J23 / 89, C01B21 / 26, 08/04/1972].

Known oxide catalyst in the form of tablets, consisting of iron oxide and aluminum oxide [SU 1220193, B01J37 / 08, S01B21 / 26, 15.11.1994]. The method for preparing the catalyst consists in mixing iron oxide and aluminum hydroxide in an acidic medium, followed by thermal decomposition of the catalyst mass at 600-700 ° C, grinding, tableting and sintering the finished tablets. Pilot tests have shown its performance at the second stage of ammonia oxidation.

The disadvantages of such catalysts include significant gas-dynamic resistance of the pelleted catalyst bed, changes in the phase composition during operation, the presence of ammonia in the gas flow after the catalyst bed, the need to make special baskets for loading the catalyst into the reactor, and catalyst spills during its operation.

These disadvantages are eliminated by the use of massive block oxide catalysts based on simple and complex oxides [RU 2117528, B01J23 / 83, 20.08.1998; RU 2100068, B01J23 / 78, 27.12.1997].

Known is a block catalyst for the oxidation of ammonia, which is a mixed oxide of the general formula (A _x B _y O _3z ) _k (Me _m O _n ) _f , where: A is the cation of Ca, Sr, Ba, Mg, Be, Ln or mixtures thereof, B - cation Mn, Fe, Ni, Co, Cr, Cu, V or mixtures thereof, x = 0-2, y = 1-2, z = 0.8-1.7, Me _m O _n - aluminum oxide and / or silicon oxide , zirconium, chromium, aluminosilicates, oxides of rare earth elements (REE) or mixtures thereof, m = 1-3, n = 1-2, k and f - wt.%, with a ratio f / k = 0.01-1 [US 6489264, B01J21 / 04, 03.12.2002]. The catalyst is obtained by extrusion molding of catalyst pastes through specially designed dies. Pastes are prepared by mixing the oxide powder A _x B _y O _3z (iron oxide or oxide with a perovskite structure), _{active in the reaction of ammonia oxidation, with structure-forming and heat-stabilizing components Me m} O _n after the introduction of an electrolyte and other additives that provide the necessary rheological properties of pastes, sufficient mechanical strength and thermal stability of blocks, as well as their resistance to thermal cycles. Massive block catalysts contain more than 50 wt% active oxide and are in the form of square or hexagonal prisms with a side size of 45-80 mm, with channels of a square or triangular cross-section and minimum dimensions of the wall and side thickness of the channel of 1.6 mm and 3.2 mm, respectively. The use of these catalysts in UKL-7 units as the 2nd stage makes it possible, without reducing the yield of nitrogen oxides, to increase the mileage of platinoid nets by 20-30%, to reduce the loading and losses of platinoids, to reduce the gas-dynamic resistance of the catalyst bed by a factor of 2-3 as compared to the pelleted oxide catalyst. and, consequently, the energy consumption for supplying gas to the reactor. The process becomes more stable, there is no ammonia breakthrough at all, which increases its safety [Chernyshev V.I., Brushtein E.A. // Catalysis in industry. 2001, No. 3, S. 30].

Known catalyst comprising as an active component oxides of Co, Fe, Bi, Cr, Mn and mixtures thereof, which may have an additive from the group including Zn, Ce, Cd and Li, and a heat-resistant support of a monolithic structure. The support materials can be titanium, zirconium and silicon dioxides, oxides of aluminum, cerium, magnesium, alkaline earth metals, lanthanum, as well as mullite, silicates and thin foils from an alloy based on iron oxides. The content of the active component in such a catalyst is 15-25 wt%. The carrier has channels with a hydraulic diameter of 0.8-30 mm and a void volume of 60-85%. The method of preparing such a catalyst consists in spreading the active component from salt suspensions [RU 2106908, B01J23 / 78, С01В21 / 6, 03/20/1998]. The disadvantage of this catalyst is a rather low yield of nitrogen oxides, which is apparently due to the low selectivity of the catalyst, possibly due to the interaction of the active component and the carrier at the stage of catalyst preparation, as well as the low strength of the coating applied from suspensions.

Known is a block catalyst for the oxidation of ammonia, which is a mixed oxide of the general formula (A _x B _y O _3z ) _k (M _m O _n ) _f (N _w P _g O _v ) _r , where: A is the cation of Ca, Sr, Ba, Mg, Be, Ln or their mixtures, B - cation Mn, Fe, Ni, Co, Cr, Cu, V, Al or their mixtures, x = 0-2, y = 1-2, z = 0.8-1 , 7, M is Al, Si, Zr, Cr, Ln, Mn, Fe, Co, Cu, V, Ca, Sr, Ba, Mg, Be or their mixtures, m = 1-3, n = 1-2 ; N is Ti, Al, Si, Zr, Ca, Mg, Ln, W, Mo or mixtures thereof, P is phosphorus, O is oxygen; w = 0-2, g = 0-2, v = 1-3; k, f and r - wt%, with the ratio (k + f) / r = 0-1, f / r = 0-1, k / f = 0-100 [RU 2251452, B01J23 / 78, С01В21 / 26 , 10.05.2005]. The catalyst is obtained by applying an active component to a previously prepared support, which is used, for example, titanium dioxide, aluminosilicates, cordierite, mullite, corundum and other thermostable materials with low values of the coefficient of thermal expansion (CTE ~ 10 ^-6 ). The main difficulties in the development of such catalysts are the interaction of the active component and the support, which reduces the activity of the catalyst and the selectivity of the process, as well as the low strength of the coating of the active component, which is destroyed during operation. To reduce the interaction of the active component and the carrier, as well as to increase the adhesion strength of the active component and the carrier, a thermal stabilizing component of the catalyst (secondary carrier) is applied to the surface of the block carrier by the method of impregnation from viscous polymer-salt compositions. Testing the stability of these catalysts to long-term operation in industrial conditions for 3 months shows that the catalyst retains high strength, but the level of activity and selectivity decreases slightly [Isupova LA, Sutormina EF, Kulikovskaya NA, Plyasova LM, Rudina NA, Ovsyannikova IA, Zolotarskii IA , Sadykov VA // Catalysis Today, 2005. V.105, P.429].

As a prototype of a block honeycomb catalyst for the oxidation of ammonia to nitrogen oxides, a catalyst was chosen, which is a mixed oxide of the general formula: ((2-x) MgO xMeO) (2-y) Al ₂ O ₃ (5 + y + (2-x)) SiO ₂ , where: x = 0-2; y = 0-0.5; Me is Mn, Fe, Co, Ni, Cu, Cr, V or their mixtures, which form the framework structure of cordierite [RU 2234977, B01J23 / 78 C01B21 / 66, 27.08.2004]. The catalyst is characterized by a coefficient of thermal expansion of 10 ^-7 -10 ^-5 K ^-1 in the temperature range up to 900 ° C, rather high activity and selectivity, and resistance to thermal cycles. The prototype catalyst is prepared using natural materials - talc Onotsky (composition 52% SiO ₂ , 30% MgO, 3% Al ₂ O _{3, the} rest is magnesite, dolomite, chlorite) and Ob clay (composition 43% SiO ₂ , 38% Al ₂ O ₃ , 4% other oxides, 15% water) as well as MeO oxides. A mixture of reagents in the required proportion is subjected to mechanical activation, then mixed with solutions of surfactants (surfactants) to form a plastic paste and molded by extrusion in the form of blocks with unidirectional channels.

The disadvantage of this catalyst is that the active component MeO is almost completely included in the structure of cordierite, which leads to a decrease in the activity and selectivity of the catalyst, as well as to a decrease in the strength of the catalyst due to the formation of defective (with a lack of MeO) cordierite. In addition, the use of refractory clay leads to a significant increase in the catalyst calcination temperature to obtain the cordierite phase.

The invention solves the problem of developing an effective catalyst for the oxidation of ammonia to nitric oxide (II) in the production of weak nitric acid.

The technical result is a high activity and strength of the claimed catalyst due to the optimization of its composition and the proposed preparation method, as well as an increase in the duration of the run of the catalyst gauzes as part of a two-stage catalytic system during the oxidation of ammonia to nitric oxide (II).

The problem is solved by a catalyst of a block honeycomb structure for the oxidation of ammonia to nitric oxide (II) based on mixed oxides of the general formula: (МеО) _x (Mg _2-y Mp _y Al ₄ Si ₅ O ₁₈ ) _1-x , where x = 0.01 -0.2; y = 0.05-0.2; MeO is the active component of the catalyst, Me is Mn, Fe, Co, Ni, Cu, Cr, V and / or mixtures thereof; Mp - promoter - Fe, K, Na, Li, Ca, Ti or mixtures thereof, and Mg _2-y Mp _y Al ₄ Si ₅ O ₁₈ is a form-forming component of the catalyst having a cordierite structure.

The problem is also solved by the method of preparing a catalyst of a block honeycomb structure for the conversion of ammonia into nitric oxide (II), which consists in mixing the active component and the precursor of the forming component of the catalyst - cordierite Mg_2-yMp_yAl_fourSi_fiveO_eighteen... As a precursor of cordierite, a mechanically activated mixture of bentonite, technical hydrate of alumina and talc is used in the required proportion, which together with MeO in the presence of surfactant solutions, they are mixed until a plastic paste is formed, followed by its extrusion molding in the form of honeycomb blocks - rectangular or hexagonal prisms with unidirectional rectangular, or triangular, or round channels with an open contact surface from 15 to 70% - by drying them and calcining. The resulting catalyst has the following composition: (MeO)_x(Mg_2-yMp_yAl_fourSi_fiveO_eighteen)_1-xwhere x = 0.01-0.2; y = 0.05-0.2; MeO is the active component of the catalyst, Me is Mn, Fe, Co, Ni, Cu, Cr, V and / or their mixtures, Mp is the promoter - Fe, K, Na, Li, Ca, Ti or their mixtures, Mg_2-yMp_yAl_fourSi_fiveO_eighteen - a shape-generating component of the catalyst having a cordierite structure.

The problem is also solved by the process of catalytic conversion of ammonia, including passing the reaction gas mixture containing ammonia and oxygen-containing gas through a two-stage catalytic system formed by various methods, including complete with trapping palladium grids and / or inert grids at the 1st stage and additional nozzles in the second stage, characterized in that the catalyst described above is used in the second stage.

The fundamental difference between the proposed catalyst and the prototype [RU 2234977 B01J23 / 78, C01B21 / 66, 27.08.2004] is that the active component in the proposed the catalyst is practically not included in the structure of cordierite, which provides a higher catalytic activity of such systems. This result is achieved by the stoichiometric composition of the initial charge and the conditions for preparing the catalyst. The starting reagents, with the exception of the active component, taken in the required ratio for the formation of a structure characteristic of a mixed oxide with a cordierite structure (Mg₂Al_fourSi_fiveO_eighteen = 2MgO * 2Al₂O₃* 5SiO₂), subjected to mechanochemical activation. A precursor of the active component MeO and a surfactant solution are added to the resulting activated product at the stage of mixing (preparation of a moldable paste). The resulting plastic mass is extruded into blocks of different geometry. At the stage of heat treatment of the formed air-dry blocks, cordierite Mg is formed from the activated raw materials.₂Al_fourSi_fiveO_eighteen. The promoters included in the composition provide high strength and thermal stability of the blocks at a lower catalyst calcination temperature, and the active component, evenly distributed in the surface layer of the catalyst, provides a higher activity and selectivity of the catalyst.

Process the catalytic conversion of ammonia includes passing a reaction gas mixture containing ammonia and an oxygen-containing gas through a 2-stage catalytic system formed by various methods, including complete with collecting palladium and / or inert grids at the 1st stage. The block catalyst layer (2nd stage) is placed after (along the gas flow) of the 1st stage mesh stack.

The catalyst preparation method consists of the following stages.

1) Preparation of the charge. After determining its chemical composition, the initial raw material required to obtain the aluminosilicate framework of the catalyst is mixed in the required proportion and subjected to mechanical treatment in a turbo mixer for 5 minutes to ensure effective mixing, activated (in a planetary mill or vibratory ball mill or disintegrator) for a period of 1 from up to 10 minutes depending on the method. As a raw material, bentotite is used, for example, from the 10 Khutor deposit (composition 59% SiO ₂ , 19% Al ₂ O ₃ , 17% promoters, 5% water), talc Onotsky (composition 52% SiO ₂ , 30% MgO, 3% Al ₂ O ₃ , the rest is magnesite, dolomite, chlorite) and gibbsite - Al (OH) _3.

2) Preparation of paste and extrusion molding of catalyst blocks. A mixture of raw materials subjected to mechanical treatment according to claim 1 with aqueous solutions of surfactants and a precursor of the active component MeO is placed in a Z-shaped mixer and mixed until a plastic paste is formed. As MeO, any of the oxides of manganese, copper, cobalt, iron, nickel, chromium, vanadium, or a mixture thereof is used. To improve the rheological characteristics of the paste, surfactant burnout agents are added to the composition - ethylene glycol, polyethylene oxide, carboxymethylcellulose, methylcellulose, polyvinyl alcohol, glycerin, etc. Additional solid burnout additives, such as graphite, wood flour, etc., can be added to the paste. others to control the sintering stage. The resulting paste is extruded into blocks of a honeycomb structure. The shaped catalyst is a rectangular or inclined (up to 45 ° C) prisms, at the base of which there is a square or a hexagon. The prisms are pierced with unidirectional channels of square, triangular, or circular cross-section. The size of the side of the channel varies from 10 to 1.5 mm, and the size of the walls - from 1.2 to 0.2 mm. The tilt of the prism is set by the block cut angle. Other shapes can also be obtained.

3) Heat treatment of the catalyst. The molded blocks are dried in air, then dried at 400 ° C and calcined at temperatures of 1000-1300 ° C.

Chemical analysis of catalysts is carried out by flame photometry, phase analysis by X-ray methods, specific surface area is determined by BET. The determination of the compressive strength of the block is carried out by placing it on the side face between two parallel surfaces of the press and applying a compressive force until fracture. Resistance to thermal shocks is determined by the number of heat cycles maintained by the block without violating its integrity, that is, through destruction, leading to disintegration into 2 or more fragments. For one heat shift, a heating cycle of the unit is taken from room temperature to (700 ± 10) ° С for 15 minutes, followed by cooling for 15 minutes in air.

The catalytic activity of the bulk catalyst samples is tested in a pilot plant at 2.6 bar (g) and 0.89 m3 gas flow.³/ h as part of a two-stage system "platinoid grids + a fragment of a block catalyst". The temperature of the gas mixture in the reactor is controlled by thermocouples located at three points: 1) 1 mm along the flow after the platinoid nets, 2) 1-2 mm along the flow after blocky catalyst, 3) on the outside of the reactor at a height approximately corresponding to half the height of the block fragment. To reduce heat removal through the walls of the reactor, the latter is additionally heated at a length section corresponding to the location of the test block. As a rule, the temperature and composition of the gases supplied to the block catalyst (2nd stage) is determined by the composition of the platinoid gauze package installed immediately before the test sample, as well as by the initial concentration of ammonia. For a 2-stage system, a package of 5 knitted platinoid nets is installed, or a package of platinoid and trapping nets, for example, Pd / Ni-5 nets, which is placed between two Megapure-type nets. With an inlet ammonia concentration of about 10 vol.%, The temperature downstream of the meshes is in the range 855-865 ° C. The experiments are carried out in such a way that the difference between the temperatures after the meshes, after the block catalyst and on the reactor wall does not exceed 10 ° C.

The composition of the gas mixture at the inlet and outlet of the reactor is determined by IR spectroscopy and gas chromatography. In all experiments, an artificial mixture (Ar + 21% O ₂ ) is used instead of air. As a diluent gas, argon is chosen in order to measure the concentration of not only nitrogen oxides, but also nitrogen formed during the reaction, which makes it possible to reduce the nitrogen balance and evaluate the correctness of the results obtained. Determine the conversion of ammonia (X _NH3 ,%), the yield of NO (X _NO ,%) and selectivity for NO (α NO,%). "Balance by N (%)" is defined as the ratio of Σ _N (vol.%) To the concentration of ammonia in the initial mixture (NH ₃ ⁰ ) supplied to the reactor

N (%) = Σ _N / NH ₃ ⁰ * 100.

A deviation of ± 5% from the value of 100% is considered acceptable.

Calculation of selectivity for NO is carried out according to the formula:

α NO (%) = (NO + NO ₂ ) / Σ _N * 100,

where Σ _N (vol.%) = (NH ₃ + NO + NO ₂ + 2N ₂ ) is the sum of the concentrations of nitrogen-containing compounds at the reactor outlet.

The activity of the two-stage system is compared with the activity of a package of 5 platinoid networks.

The invention is illustrated by the following examples of the preparation of catalysts and the results of their characterization and testing during the oxidation of ammonia, shown in Tables 1, 2. Data on the catalytic activity in the oxidation of ammonia were obtained for a two-stage system consisting of 5 platinoid grids and a fragment of a block catalyst with square channels. section and open surface 50%. For comparison, data from tests with a prototype and a single-stage system (only platinoid grids) are shown.

Example 1 (prototype).

The turbomixer is charged with 31.76 weight parts (wp) of talc from the Onotsky deposit (composition 52% SiO ₂ , 30% MgO, 3% Al ₂ O _{3, the} rest is magnesite, dolomite, chlorite), 40.42 wp. Obskoy clay (composition 43% SiO ₂ , 38% Al ₂ O ₃ , 4% promoters, 15% water), 14.82 wt. Gibbsitt, 10 v.ch. cordierite powder, 3 v.h. manganese dioxide and stirred for 5 minutes. The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of methylcellulose (MC), 1 g of wood flour is added and mixed for 30-40 minutes until a homogeneous plastic mass is formed with a moisture content of 24-26% ... The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1000-1100-1200 ° C for 4 hours.

The finished catalyst meets the formula

1.97MgO 0.03MnO 1.99Al ₂ O ₃ 5.015SiO ₂ (or Mg _1.97 Mn _0.03 Al _3.98 Si _5.01 O _18-0.01 ).

Example 2.

The turbomixer is charged with 32.86 v.h. talcum of the Onotsky deposit, 41.82 wt. bentonite of the 10 khutor deposit (composition 59% SiO ₂ , 19% Al ₂ O ₃ , 17% promoters, 5% water), 15.32 wt. Gibbsitt, 10 v.ch. cordierite powder and stirred for 5 minutes. The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of MC, 1 g of wood flour and 3 g of manganese ore is added, mixed for 30-40 minutes until a homogeneous plastic mass with a moisture content of 24 26%. The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm, with an open contact surface of 50%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1000-1100-1200 ° C for 4 hours.

The finished catalyst meets the formula

(MnO) _0.03 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.97, where: Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 3.

The paste is prepared analogously to example 2. The paste is used to form blocks of a honeycomb structure in the form of a square with a side of 30 mm and square channels with a side of 3 mm and a wall thickness of 0.6 mm, with an open contact surface of 70%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(MnO) _0.03 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.97, where: Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 4.

The paste is prepared analogously to example 2. The paste is used to form blocks of a honeycomb structure in the form of a square with a side of 30 mm and round channels with a diameter of 1.7 mm and a wall thickness of 2.0 mm, with an open contact surface of 15%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(MnO) _0.03 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.97, where: Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 5.

The turbomixer is charged with 32.86 v.h. talcum of the Onotsky deposit, 41.82 wt. bentonite of the 10 khutor deposit, 15.32 wt. gibbsite, 10 v.ch. cordierite powder and stirred for 5 minutes. The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of MC, 1 g of wood flour and 10 g of iron (III) oxide is added, stirred for 30-40 minutes until a homogeneous plastic mass is formed with humidity 24-26%. The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm, with an open contact surface of 50%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(Fe ₂ O ₃ ) _0.1 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.9, where Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 6.

The turbomixer is charged with 32.86 v.h. talcum of the Onotsky deposit, 41.82 wt. bentonite of the 10 khutor deposit, 15.32 wt. gibbsite, 10 v.ch. cordierite powder and stirred for 5 minutes. The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of MC, 1 g of wood flour, 10 g of vanadium (V) oxide and 10 g of iron (III) oxide is added, stirred for 30- 40 minutes until a homogeneous plastic mass with a moisture content of 24-26% is formed. The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm, with an open contact surface of 50%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(Fe ₂ O ₃ ⋅V ₂ O ₅ ) _0.2 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.8, where Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 7.

The paste is prepared analogously to example 6. Instead of vanadium (V) oxide, chromium (III) oxide is used.

The finished catalyst meets the formula

(Fe ₂ O ₃ ⋅Cr ₂ O ₃ ) _0.2 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.8, where Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 8.

The turbomixer is charged with 32.86 v.h. talcum of the Onotsky deposit, 41.82 wt. bentonite of the 10 khutor deposit, 15.32 wt. gibbsite, 10 v.ch. cordierite powder and stirred for 5 minutes. The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of MC, 1 g of wood flour and 1.5 g of copper (I) oxide is added, stirred for 30-40 minutes until a homogeneous plastic mass is formed with humidity 24-26%. The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm, with an open contact surface of 50%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(Cu ₂ O) _0.01 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.99, where Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 9.

The turbomixer is charged with 32.86 v.h. talcum of the Onotsky deposit, 41.82 wt. bentonite of the 10 khutor deposit, 15.32 wt. gibbsite, 10 v.ch. cordierite powder and stirred for 5 minutes. The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of MC, 1 g of wood flour and 10 g of cobalt (III) oxide is added, stirred for 30-40 minutes until a homogeneous plastic mass is formed with humidity 24-26%. The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm, with an open contact surface of 50%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(Co ₃ O ₄ ) _0.1 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.9, where Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 10.

The turbomixer is charged with 32.86 v.h. talcum of the Onotsky deposit, 41.82 wt. bentonite of the 10 khutor deposit, 15.32 wt. gibbsite, 10 v.ch. cordierite powder and stirred for 5 minutes. The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of MC, 1 g of wood flour and 10 g of nickel (II) oxide is added, stirred for 30-40 minutes until a homogeneous plastic mass is formed with humidity 24-26%. The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm, with an open contact surface of 50%. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(NiO) _0.1 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.9, where Mp is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

Example 11.

The turbomixer is charged with 40.25 v.h. talcum powder of the Onotsky deposit, 36.86 wt. Obskoy clay (composition 43% SiO ₂ , 38% Al ₂ O ₃ , 4% promoters, 15% water), 12.89 p.h. gibbsite, 10 v.ch. cordierite powder and stirred for 5 minutes.

The prepared mixture in the required amount of 100-110 g is loaded into a planetary mill and subjected to activation at an acceleration of 20 g for 5 minutes. 100 g of the activated mixture is loaded into a Z-shaped mixer with a capacity of 0.5 l, a 0.5% solution of MC, 1 g of wood flour, 3 g of manganese dioxide is mixed for 30-40 minutes until a homogeneous plastic mass with a moisture content of 24-26% is formed. The paste is used to form blocks of a honeycomb structure in the form of a hexagon with a side of 20 mm and triangular channels with a side of 2 mm and a wall thickness of 0.6 mm. The blocks are dried to an air-dry state, dried at 400 ° C for 4 hours with a temperature rise rate of an average of 30 ° C / h. Then it is calcined at 1100 ° С for 4 h.

The finished catalyst meets the formula

(MnO) _0.03 (Mg _1.98 Mp _0.02 Al ₄ Si ₅ O ₁₈ ) _0.97, where Me is a mixture of Fe, K, Na, Li, Mg, Ca, Ti.

As can be seen from the above examples (Tables 1-2), the strength, thermal stability and selectivity of the new catalysts exceed the characteristics of the prototype even at lower calcination temperatures.

Thus, the invention solves the problem of developing a catalyst for the oxidation of ammonia, characterized by a higher activity, strength and thermal stability in comparison with the prototype by optimizing the composition of the catalyst, the optimal method of introducing the active component into the catalyst and the raw materials used.

Table 1 - Physicochemical properties of catalysts.

Example # Chemical composition Calcination temperature, ° С Strength N / product Thermal shock open contact 1 prototype 1.97MgO 0.03MnO 1.99Al ₂ O ₃ 5.015SiO ₂
(or Mg _1.97 Mn _0.03 Al _3.98 Si _5.01 O _18-0.01 ) 1000 7000 nine fifty 1100 8000 10 1200 10000 12 2 (MnO) _0.03 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.97 1000 9000 12 fifty 1100 11000 12 1200 13000 12 3 (MnO) _0.03 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.97 1100 8500 12 70 four (MnO) _0.03 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.97 1100 21000 12 fifteen five (Fe ₂ O ₃ ) _0.1 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.9 1100 11000 12 fifty 6 (Fe ₂ O ₃ ⋅V ₂ O ₅ ) _0.2 (Mg _1.94 Mp _0.06 ) Al ₄ Si ₅ O ₁₈ ) _0.8 1100 10000 12 fifty 7 (Fe ₂ O ₃ ⋅Cr ₂ O ₃ ) _0.2 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.8 1100 12000 12 fifty eight (Cu ₂ O) _0.01 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.99 1100 11000 12 fifty nine (Co ₃ O ₄ ) _0.1 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.9 1100 11000 12 fifty 10 (NiO) _0.1 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.9 1100 11000 12 fifty eleven (MnO) _0.03 (Mg _1.98 Mp _0.02 Al ₄ Si ₅ O ₁₈ ) _0.97 1100 8000 eleven fifty

Table 2 - Data on the catalytic activity of two-stage systems in the reaction of ammonia oxidation (* - data on the activity of only platinoid networks - 1st stage are given).

Example No. Catalyst composition X (NH ₃ ) X (NO) α (NO) 1 prototype 1.97MgO 0.03MnO 1.99Al ₂ O ₃ 5.015SiO ₂
(Mg _1.94 Mn _0.06 Al ₄ Si ₅ O ₁₈ ) 100.0 91.3 / 92.6 91.3 / 92.6 2 (MnO) _0.03 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.97 100.0 92.1 / 93.5 92.1 / 93.5 five (Fe ₂ O ₃ ) _0.1 (Mg _1.94 Mp _0.06 ) Al ₄ Si ₅ O ₁₈ ) _0.9 100.0 92.5 92.5 6 (Fe ₂ O ₃ ⋅V ₂ O ₅ ) _0.2 (Mg _1.94 Mp _0.06 ) Al ₄ Si ₅ O ₁₈ ) _0.8 100.0 92.9 92.9 7 (Fe ₂ O ₃ ⋅Cr ₂ O ₃ ) _0.2 (Mg _1.94 Mp _0.06 ) Al ₄ Si ₅ O ₁₈ ) _0.8 100.0 92.0 92.0 eight (Cu ₂ O) _0.01 (Mg _1.94 Mp _0.06 Al ₄ Si ₅ O ₁₈ ) _0.99 100.0 93.4 93.4 nine (Co ₃ O ₄ ) _0.1 (Mg _1.94 Mp _0.06 ) Al ₄ Si ₅ O ₁₈ ) _0.9 100.0 92.5 92.5 10 (NiO) _0.1 (Mg _1.94 Mp _0.06 ) Al ₄ Si ₅ O ₁₈ ) _0.9 100.0 92.7 92.7 eleven (MnO) _0.03 (Mg _1.98 Mp _0.02 Al ₄ Si ₅ O ₁₈ ) _0.97 100.0 92.0 / 92.8 92.0 / 92.8 * 5 platinoid meshes 99.8 88.0 89.7

Claims (4)

1. A catalyst of a block honeycomb structure for the oxidation of ammonia to nitric oxide (II), which is a mixed oxide of the general formula (MeO) _x (Mg _2-y Mр _y Al ₄ Si ₅ O ₁₈ ) _1-x , where x = 0.01 -0.2, y = 0.05-0.2, MeO is the active component of the catalyst, Me is Mn, Fe, Co, Ni, Cu, Cr, V and / or mixtures thereof, Mp is a promoter that is a mixture Fe, K, Na, Li, Ca, Ti, Mg _2-y Mр _y Al ₄ Si ₅ O ₁₈ is a shape-generating component of the catalyst having a cordierite structure. 2. A method of preparing a catalyst of a block honeycomb structure for the oxidation of ammonia to nitric oxide (II), which consists in mixing the precursor of the forming component of the catalyst - cordierite Mg _2-y Mр _y Al ₄ Si ₅ O ₁₈ , where a mechanically activated mixture of bentonite, technical hydrate of alumina and talc, and the active component MeO in the presence of a solution of surfactants to form a plastic paste, followed by its extrusion molding in the form of honeycomb blocks, drying and calcining them, so that the resulting catalyst has the composition (MeO) _x (Mg _{2- y} Mр _y Al ₄ Si ₅ O ₁₈ ) _1-x , where x = 0.01-0.2, y = 0.05-0.2, MeO is the active component of the catalyst, Me is Mn, Fe, Co, Ni, Cu, Cr, V and / or their mixtures, Мp is a promoter that is a mixture of Fe, K, Na, Li, Ca, Ti, Mg _2-y Mр _y Al ₄ Si ₅ O ₁₈ is a form-forming component of the catalyst having structure of cordierite. 3. A method according to claim 2, characterized in that the catalyst is formed in the form of rectangular or hexagonal prisms with unidirectional channels of a rectangular, or triangular, or circular shape with an open contact surface from 15 to 70%. 4. The process of oxidation of ammonia to nitric oxide (II), including passing a reaction gas mixture containing ammonia and an oxygen-containing gas through a two-stage catalytic system formed by various methods from catalyst, trapping and inert nets at the 1st stage and a block catalyst layer at the 2nd, which differs the fact that in the 2nd stage use a catalyst according to claim 1 or prepared according to claims. 2, 3.