阅读说明：本技术 一种硫酸氧钛负载五氧化二铌的高温脱硝催化剂 (High-temperature denitration catalyst of titanyl sulfate-loaded niobium pentoxide ) 是由 王勇 薛薇 王飞 杨杭生 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种硫酸氧钛负载五氧化二铌的高温脱硝催化剂,该高温脱硝催化剂采用硫酸氧钛(TiOSO-(4))作为五氧化二铌(Nb-(2)O-(5))催化剂的载体；利用TiOSO-(4)表面的强酸性保证在高温下仍然能够有效吸附NH-(3),从而有利于高温SCR反应的进行。在此基础上,将五氧化二铌(Nb-(2)O-(5))负载于硫酸氧钛(TiOSO-(4))载体上,利用Nb-(2)O-(5)较弱的氧化能力,在保证有效催化脱硝反应的同时,成功抑制高温下NH-(3)的深度氧化反应,保证了催化剂在300-500℃的高温脱硝活性和优异氮气选择性。(The invention discloses a high-temperature denitration catalyst of titanyl sulfate-loaded niobium pentoxide, which adopts titanyl sulfate (TiOSO) 4 ) As niobium pentoxide (Nb) 2 O 5 ) A support for the catalyst; using TiOSO 4 The strong acidity of the surface ensures that NH can still be effectively adsorbed at high temperature 3 Thereby being beneficial to the high-temperature SCR reaction. On the basis of the above-mentioned material, niobium pentoxide (Nb) 2 O 5 ) Supported on titanyl sulfate (TiOSO) 4 ) On a carrier, using Nb 2 O 5 Weak oxidizing power, in heat preservationWhile proving to effectively catalyze the denitration reaction, successfully inhibit NH at high temperature 3 The deep oxidation reaction ensures the high-temperature denitration activity and excellent nitrogen selectivity of the catalyst at the temperature of 300-500 ℃.)

1. The high-temperature denitration catalyst of titanyl sulfate-loaded niobium pentoxide is characterized in that TiOSO is contained in the catalyst₄The mass percentage content of the components is 0.1-30%; nb₂O₅The mass percentage of the components is 70-99.9%.

2. The high-temperature denitration catalyst of titanyl sulfate-supported niobium pentoxide as claimed in claim 1, wherein the preparation method comprises the following steps:

(1) mixing titanyl sulfate and niobium salt, and putting the mixture into a ball milling tank for mechanical ball milling;

(2) calcining the solid after mechanical ball milling to obtain TiOSO₄Loaded Nb₂O₅The catalyst of (1).

3. The catalyst as claimed in claim 2, wherein the mass ratio of the titanyl sulfate to the niobium salt is 10:1-4: 1.

4. The catalyst as claimed in claim 2, wherein the niobium salt is at least one of niobium oxalate or niobium chloride.

5. The high-temperature denitration catalyst of titanyl sulfate-loaded niobium pentoxide as claimed in claim 2, wherein the ball milling rotation speed is 100r/min-400r/min, and the ball milling time is 30min-180 min.

6. The catalyst as claimed in claim 2, wherein the calcination temperature is 400-600 ℃ and the calcination time is 30-400 min.

Technical Field

The invention belongs to the fields of environmental protection technology and denitration catalysis, and particularly relates to a high-temperature denitration catalyst of titanyl sulfate-loaded niobium pentoxide.

Background

NO_xThe excessive discharge brings a series of environmental problems such as acid rain, photochemical smog, greenhouse effect and the like, and NO simultaneously_XAlso has certain biological toxicity, which is not good for human health. Currently, social development puts higher demands on environmental protection, and emission standards of nitrogen oxides are becoming stricter, so that more advanced nitrogen oxide removal technologies are required. At present, the most widely commercialized technology is SCR denitration technology, and the core of the technology is V₂O₅-WO₃/TiO₂A catalyst having a catalytic performance of approximately 100% at 300 ℃ and 400 ℃. However, the catalyst may cause NH at high temperatures₃Deep oxidation of (2) to produce a large amount of by-product N₂O, lowering denitration performance and lowering N₂Selectivity and V₂O₅Has biological toxicity and is difficult to recover and treat.

With the emergence of the porous ceramic-based high-temperature dust removal and denitration integrated technology, the working temperature of dust removal can overcome the defect that the conventional cloth bag cannot resist high temperature and is close to 500 ℃, so that a novel catalyst at the temperature of 400-500 ℃ needs to be developed to meet the application requirement of the denitration and dust removal integrated technology.

Disclosure of Invention

The invention aims to provide high-stability NH suitable for the high-temperature smoke temperature range of 400-500 DEG C₃-an SCR denitration catalyst. At present, studies have shown that TiO treated with sulfuric acid₂The carrier can enhance the adsorption of NH on the surface of the catalyst₃However, the method is not only complex in preparation method, but also has limited improvement on surface acidity. In order to overcome the defects of the existing high-temperature denitration catalyst technology, the invention innovatively adopts TiOSO₄AsNb₂O₅The high-temperature denitration catalyst is prepared by a simple mechanical ball milling method through a carrier of the base catalyst.

The invention is realized by adopting the following technical scheme:

TiOSO in high-temperature denitration catalyst of titanyl sulfate-loaded niobium pentoxide₄The mass percentage content of the components is 0.1-30%; nb₂O₅The mass percentage of the components is 70-99.9%.

The preparation method of the catalyst comprises the following steps:

(1) mixing titanyl sulfate and niobium salt in a proper mass ratio, and putting the mixture into a ball milling tank for mechanical ball milling;

(2) calcining the solid after mechanical ball milling at high temperature to obtain TiOSO₄Loaded Nb₂O₅The catalyst of (1).

The high-temperature denitration catalyst of titanyl sulfate-loaded niobium pentoxide also comprises the following preferable scheme.

In a preferred embodiment of the present invention, the mass ratio of the titanyl sulfate to the niobium salt used in step (1) is 10:1 to 4:1, and the niobium salt is at least one of niobium oxalate or niobium chloride.

In the preferable scheme of the invention, the ball milling speed in the step (2) is 100r/min-400r/min, and the ball milling time is 30min-180 min.

In a preferred embodiment of the present invention, the calcination temperature in step (3) is 400-600 ℃, and the calcination time is 30-400 min.

The denitration principle of the catalyst provided by the invention is as follows:

using TiOSO₄Strongly acidic at high temperature to adsorb NH₃Using Nb₂O₅In the case of activated NH₃While effectively inhibiting NH₃Deep oxidation of (2). Ensures that excellent N is maintained while the denitration reaction is effectively catalyzed at the high temperature of 300-500-₂And (4) selectivity.

Compared with the prior art, the invention has the beneficial effects that:

TiOSO is used as the catalyst₄As a carrier, with Nb₂O₅As an active component, the high-temperature SCR denitration catalyst suitable for 300-500 ℃ is prepared by adopting a mechanical ball milling method. The method is mainly realized by the following two aspects:

(1)NH₃adsorption and activation of acid sites on the surface of the catalyst are important steps in the SCR reaction, while NH is present at high temperatures₃And the catalyst is difficult to adsorb on the surface of the catalyst, so that the improvement of the surface acidity is important for the high-temperature denitration catalyst. Based on this, the invention adopts TiOSO₄As a carrier, the prepared catalyst has a large number of acid sites, thereby showing excellent denitration activity.

(2) The oxidation capability of the metal oxide catalyst at high temperatures readily leads to NH₃Deep oxidation of Nb₂O₅Has a weak oxidizing power, and the use of the catalyst as an active component can suitably reduce the oxidizing power of the catalyst and suppress NH₃Thereby further improving the denitration activity and the nitrogen selectivity of the catalyst.

Drawings

FIG. 1 is a graph showing the denitration activity and nitrogen selectivity test of catalysts prepared in examples 1 to 3; (a) NO conversion and (b) N₂Selectivity;

FIG. 2 is a graph showing stability tests of the catalyst prepared in example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A titanyl sulfate-loaded niobium pentoxide high-temperature denitration catalyst and a preparation method thereof comprise the following implementation steps: (1) 10g of TiOSO are first introduced₄·2H₂O with 2.47g of C₁₀H₅NbO₂₀Mixing, putting into a ball milling tank, and preparing tungsten carbide grinding balls with different quantities and sizes; (2) setting the rotating speed of the ball mill to be 300r/min, and carrying out ball milling for 120 minutes; (3) calcining the ball-milled mixture in air atmosphere for 30min to obtain TiOSO₄Loaded Nb₂O₅The catalyst of (1).

Example 2

(1) 10g of TiOSO are first introduced₄·2H₂O and 7.41g of C₁₀H₅NbO₂₀Mixing, putting into a ball milling tank, and preparing tungsten carbide grinding balls with different quantities and sizes; (2) setting the rotating speed of the ball mill to be 300r/min, and carrying out ball milling for 120 minutes; (3) calcining the ball-milled mixture for 5 hours in air atmosphere to obtain TiOSO₄Loaded Nb₂O₅The catalyst of (1).

Example 3

(1) 10g of TiOSO are first introduced₄·2H₂O with 1.235g of C₁₀H₅NbO₂₀Mixing, putting into a ball milling tank, and preparing tungsten carbide grinding balls with different quantities and sizes; (2) setting the rotating speed of the ball mill to be 300r/min, and carrying out ball milling for 120 minutes; (3) calcining the ball-milled mixture for 5 hours in air atmosphere to obtain TiOSO₄Loaded Nb₂O₅The catalyst of (1).

The denitration activity test of the catalyst prepared in the embodiment 1-3 specifically comprises the following steps: (1) weighing the prepared 40-60 mesh (0.5g) catalyst, and putting the catalyst into a fixed bed quartz reaction tube; (2) the composition of the gas at the inlet of the reaction tube was 500ppm NO, 500ppm NH₃、5vol％O₂，N₂As carrier gas, the total flow rate of the gas is 600sccm, and the volume space velocity of the catalyst is 72000h^-1The reaction temperature is 300-500 ℃. The denitration activity and nitrogen selectivity test results of the catalysts prepared in examples 1 to 3 are shown in fig. 1. It can be seen from fig. 1a that the denitration efficiency of the catalyst prepared in example 1 at 300-500 ℃ is always higher than that of the catalysts prepared in examples 2 and 3. As can be seen from FIG. 1b, the catalyst prepared by the method of the present invention has 100% nitrogen selectivity at 500 ℃ under 300 ℃ without generating N as a by-product₂O。

The catalyst prepared in example 1 was subjected to a high temperature stability test, which specifically comprises the following steps: (1) weighing the prepared 40-60 mesh (0.5g) catalyst, and putting the catalyst into a quartz reaction tube of a fixed bed; (2) the composition of the gas at the inlet of the reaction tube was 500ppm NO, 500ppm NH₃、5vol％O₂，N₂As carrier gas, the total flow rate of the gas is 600sccm, and the volume space velocity of the catalyst is 72000h^-1The reaction temperature was 500 ℃. The results of the high temperature stability test of the catalyst prepared in example 1 are shown in fig. 2. As can be seen from fig. 2, the catalyst prepared in example 1 of the present invention has excellent high temperature stability at 500 ℃.

In summary, TiOSO is used in the invention₄As a carrier, with Nb₂O₅The high-temperature SCR denitration catalyst prepared by adopting a mechanical ball milling method has excellent high-temperature denitration activity and nitrogen selectivity and can be used for industrial high-temperature denitration.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.