CN111068709A

CN111068709A - Preparation method of ferro-manganese catalyst

Info

Publication number: CN111068709A
Application number: CN201811231868.7A
Authority: CN
Inventors: 不公告发明人
Original assignee: Haimen Yuanmei Art Pattern Design Co ltd
Current assignee: Haimen Yuanmei Art Pattern Design Co ltd
Priority date: 2018-10-22
Filing date: 2018-10-22
Publication date: 2020-04-28

Abstract

The invention discloses a preparation method of a ferro-manganese catalyst, which comprises the following steps: adding manganese oxide nanoparticles into deionized water, performing ultrasonic dispersion for 40-50min, adding a ferric nitrate solution, dropwise adding ammonia water under the condition of magnetic stirring until the pH value is 2.4-2.6, transferring the mixed solution into a hydrothermal reaction kettle, placing the hydrothermal reaction kettle in an oven for hydrothermal reaction at 165-175 ℃ for 4-5h, separating and washing, drying the obtained solid at 65-75 ℃ for 23-25h, finally calcining the solid at 380-390 ℃ in an oxygen atmosphere for 4-5h, and cooling to obtain the manganese oxide nanoparticle. The method is simple, convenient, fast and easy to operate, and the prepared ferro-manganese catalyst has high NO catalysis_xThe catalyst has high activity, excellent water and sulfur resistance and may be prepared in large scale.

Description

Preparation method of ferro-manganese catalyst

Technical Field

The invention relates to a preparation method of a ferro-manganese catalyst.

Background

Nitrogen oxides (NO and NO)₂) Mainly from automobile exhaust, fossil fuel combustion and industrial exhaust, which are one of the main pollutants of atmospheric pollution. They cause a series of serious environmental problems such as photochemical smog, acid rain, ozone depletion, greenhouse effect, and the like. NH (NH)₃Selective catalytic reduction of NO (Selective catalytic reduction of NO with NH)₃，NH₃-SCR) technology, with high selectivity and efficiency, most widely used in fixed source flue gas denitration. The SCR catalyst is the core of the technology and is very important for realizing the high-efficiency removal of NOx. V₂O₅-WO₃(MoO₃)/TiO₂The system catalyst is a commercial catalyst commonly used in the industry at present, the reaction temperature is generally about 350-400 ℃, an SCR denitration device is generally arranged in front of a dust removal and desulfurization device, but the catalyst is easily inactivated due to a large amount of dust, trace elements (such As K, Na, Ca, As and the like) and SO2 and other gases contained in the flue gas at the section. When the denitration device is arranged behind the dust removal and desulfurization device, the denitration device can be provided withThe above problems are effectively avoided. However, the denitration activity of the current commercial catalyst is difficult to guarantee under the temperature (< 160 ℃) condition in the area. Therefore, the development of a catalyst having good SCR activity in a low temperature section has been an important research direction in the field of flue gas denitration.

Active components of the low-temperature SCR catalyst researched at present mainly comprise transition metals, mainly comprising V, Ce, Cu, Mn, Fe, Cr and the like. Wherein, Mn/TiO₂、MnOx-CeO₂And Fe-MnO_xNH at low temperature with Mn-based metal oxide catalyst₃Relatively high activity is shown during the SCR reaction. Manganese oxide based catalyst at low temperature NH₃Higher catalytic performance in the SCR reaction, which is probably related to the valence electron structure of manganese, which is 3d⁵4s²I.e. having 7 valence electrons, more variable valence relative to other transition metals, and easy transition between oxidation states at low temperature, resulting in its conversion to NH₃The SCR reaction has stronger low-temperature catalytic activity. Research finds that various factors such as the oxidation state, the crystal structure and the surface structure of the manganese oxide determine the catalytic performance. In addition, a great deal of literature research shows that part of transition metal elements as an auxiliary agent can effectively improve the low-temperature denitration activity of the catalyst. Research shows that Fe₃Mn₃O₈The presence of (b) is one of the reasons why the catalyst has a higher activity. According to literature reports, the ferro-manganese catalyst is mostly prepared by a coprecipitation method and a citric acid method, and the research on the aspect of low-temperature denitration of the ferro-manganese catalyst prepared by a hydrothermal method is only reported.

Disclosure of Invention

The invention aims to provide a preparation method of a ferro-manganese catalyst.

The invention is realized by the following technical scheme:

the preparation method of the ferro-manganese catalyst comprises the following steps: adding 15-25 parts of manganese oxide nanoparticles into 70-80 parts of deionized water, performing ultrasonic dispersion for 40-50min, adding 65-75 parts of 0.1mol/L ferric nitrate solution, dropwise adding ammonia water under the condition of magnetic stirring until the pH value is 2.4-2.6, transferring the mixed solution into a hydrothermal reaction kettle, placing the hydrothermal reaction kettle in an oven for hydrothermal reaction at 165-75 ℃ for 4-5h, separating and washing, drying the obtained solid at 65-75 ℃ for 23-25h, finally calcining at 380-75 ℃ for 4-5h in an oxygen atmosphere at 390 ℃, and cooling to obtain the manganese oxide nanoparticle; the raw materials are in parts by weight.

Preferably, in the preparation method, ultrasonic dispersion is carried out for 45 min.

Preferably, in the preparation method, ammonia water is dropwise added to the pH value of 2.5 under the condition of magnetic stirring.

Preferably, in the preparation method, the hydrothermal reaction is carried out for 4.5h at 170 ℃ in an oven.

Preferably, in the preparation method, the obtained solid is dried for 24 hours at 70 ℃.

Preferably, in the preparation method, the calcination is carried out for 4.5h at 385 ℃ in an oxygen atmosphere.

The invention has the technical effects that:

the method is simple, convenient, fast and easy to operate, and the prepared ferro-manganese catalyst has high NO catalysis_xThe catalyst has high activity, excellent water and sulfur resistance and may be prepared in large scale.

Detailed Description

The following describes the substance of the present invention with reference to the examples.

Example 1

The preparation method of the ferro-manganese catalyst comprises the following steps: adding 20 parts of manganese oxide nanoparticles into 75 parts of deionized water, performing ultrasonic dispersion for 45min, adding 70 parts of 0.1mol/L ferric nitrate solution, dropwise adding ammonia water under the condition of magnetic stirring until the pH value is 2.5, transferring the mixed solution into a hydrothermal reaction kettle, placing the hydrothermal reaction kettle in an oven for hydrothermal reaction at 170 ℃ for 4.5h, separating and washing, drying the obtained solid at 70 ℃ for 24h, finally calcining at 385 ℃ for 4.5h in an oxygen atmosphere, and cooling to obtain the manganese oxide nanoparticle; the raw materials are in parts by weight.

Example 2

The preparation method of the ferro-manganese catalyst comprises the following steps: adding 15 parts of manganese oxide nanoparticles into 70 parts of deionized water, performing ultrasonic dispersion for 40min, adding 65 parts of ferric nitrate solution with the concentration of 0.1mol/L, dropwise adding ammonia water under the condition of magnetic stirring until the pH value is 2.4, transferring the mixed solution into a hydrothermal reaction kettle, placing the hydrothermal reaction kettle in a drying oven at 165 ℃ for hydrothermal reaction for 4h, separating and washing, drying the obtained solid at 65 ℃ for 23h, finally calcining at 380 ℃ for 4h in an oxygen atmosphere, and cooling to obtain the manganese oxide nanoparticle; the raw materials are in parts by weight.

Example 3

The preparation method of the ferro-manganese catalyst comprises the following steps: adding 25 parts of manganese oxide nanoparticles into 80 parts of deionized water, performing ultrasonic dispersion for 50min, adding 75 parts of 0.1mol/L ferric nitrate solution, dropwise adding ammonia water under the condition of magnetic stirring until the pH value is 2.6, transferring the mixed solution into a hydrothermal reaction kettle, placing the hydrothermal reaction kettle in a drying oven at 175 ℃ for 5h, performing separation and washing, drying the obtained solid at 75 ℃ for 25h, finally calcining at 390 ℃ for 5h in an oxygen atmosphere, and cooling to obtain the manganese oxide nanoparticle; the raw materials are in parts by weight.

Claims

1. The preparation method of the ferro-manganese catalyst is characterized by comprising the following steps: adding 15-25 parts of manganese oxide nanoparticles into 70-80 parts of deionized water, performing ultrasonic dispersion for 40-50min, adding 65-75 parts of 0.1mol/L ferric nitrate solution, dropwise adding ammonia water under the condition of magnetic stirring until the pH value is 2.4-2.6, transferring the mixed solution into a hydrothermal reaction kettle, placing the hydrothermal reaction kettle in an oven for hydrothermal reaction at 165-75 ℃ for 4-5h, separating and washing, drying the obtained solid at 65-75 ℃ for 23-25h, finally calcining at 380-75 ℃ for 4-5h in an oxygen atmosphere at 390 ℃, and cooling to obtain the manganese oxide nanoparticle; the raw materials are in parts by weight.

2. The method of claim 1, wherein: and ultrasonically dispersing for 45 min.

3. The method of claim 1, wherein: ammonia water was added dropwise with magnetic stirring to a pH of 2.5.

4. The method of claim 1, wherein: placing the mixture in an oven for hydrothermal reaction at 170 ℃ for 4.5 h.

5. The method of claim 1, wherein: the resulting solid was dried at 70 ℃ for 24 h.

6. The method of claim 1, wherein: calcining at 385 ℃ for 4.5h in an oxygen atmosphere.