Preparation method of low-temperature selective catalytic reduction (SCR) catalyst by removing NOx from flue gas

An SCR catalyst and catalyst technology, applied in chemical instruments and methods, physical/chemical process catalysts, separation methods, etc., can solve the problems of catalyst alkali metal poisoning, space behind the furnace, dust blockage, etc., to improve the degree of dispersion and combination. Strength, high NO removal rate, effect of reducing operating temperature

Active Publication Date: 2011-04-13
GUODIAN SCI & TECH RES INST +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The catalyst used is mainly V 2 o 5 /TiO 2 series, it has very high catalytic activity, but it mainly has the following disadvantages in domestic applications: First, the reaction temperature is relatively high, and the general operating temperature is about 350 ° C. In order to meet the temperature requirements, the catalytic bed is generally arranged in the dust collector before, but on the one hand this arrangement will cause the SO of the catalyst 2 and alkali metal poisoning, as well as dust blockage, on the other hand, a larger space behind the furnace is required; second, the vanadium V in the active component is poisonous, which is harmful to the ecological environment and human health

Method used

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  • Preparation method of low-temperature selective catalytic reduction (SCR) catalyst by removing NOx from flue gas
  • Preparation method of low-temperature selective catalytic reduction (SCR) catalyst by removing NOx from flue gas

Examples

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Embodiment 1

[0033] Dissolve titanium sulfate in water, add 30% ammonia water drop by drop to get white Ti(OH) 4 Precipitation, after the precipitation is complete, filter and wash to remove sulfate ions. Dissolve the white precipitate completely with nitric acid with a concentration of 20%, add manganese nitrate and cerium nitrate to the solution, and then gradually add ammonia water with a concentration of 30% to obtain the precipitate, filter, wash, dry at 120°C, and then Calcined at 450°C for 6h to obtain Mn-Ce / TiO 2 catalyst. Wherein the molar ratio is: Mn:Ce:Ti=0.4:0.05:1.

[0034] Prepared Mn-Ce / TiO 2 Catalyst XRD see figure 1 , A in the figure represents anatase, and B represents brookite. It can be seen from the peak characteristics of XRD that only two peaks of anatase and brookite appear, and no peaks related to Mn and Ce appear, that is, no crystal phase containing Mn is detected. It shows that the dispersion of Mn and Ce oxides in the catalyst is better, so that the cata...

Embodiment 2

[0037] Dissolve titanyl sulfate in water, and add ammonia water with a concentration of 30% dropwise to obtain white Ti(OH) 4 Precipitation, after the precipitation is complete, filter and wash to remove sulfate ions. Dissolve the white precipitate completely with nitric acid with a concentration of 20%, add manganese nitrate and cerium nitrate to the solution, and then gradually add ammonia water with a concentration of 30% to obtain a precipitate, filter, wash, dry at 120°C, and then Calcined at 450°C for 6h to obtain Mn-Ce / TiO 2 catalyst. Wherein the molar ratio is: Mn:Ce:Ti=0.3:0.1:1.

[0038] The catalyst is used for SCR denitrification of flue gas, flue gas GHSV (gas space velocity per hour) = 30000h -1 , O 2 Volume concentration 3%, denitration agent NH 3 Press NO: NH 3 =1 (molar ratio) is added, and when the reaction temperature is 100° C., the catalytic efficiency is about 85%. Add 150ppm SO in the flue gas 2 and 8% H 2 After O, the catalytic efficiency was 8...

Embodiment 3

[0040] Dissolve titanium tetrachloride in water (ice-water bath), add 10% ammonia water drop by drop to obtain white Ti(OH) 4 Precipitation, after the precipitation is complete, filter and wash to remove chloride ions. Dissolve the white precipitate completely with 20% nitric acid, add manganese nitrate and cerium nitrate to the solution, and then gradually drop in 10% ammonia water to obtain the precipitate, filter, wash, dry at 120°C, and then Calcined at 500°C for 6h to obtain Mn-Ce / TiO 2 catalyst. Wherein the molar ratio is: Mn:Ce:Ti=0.4:0.05:1.

[0041] The catalyst is used for SCR denitrification of flue gas, flue gas GHSV (gas space velocity per hour) = 30000h -1 , O 2 Volume concentration 3%, denitration agent NH 3 Press NO: NH 3 =1 (molar ratio) is added, and when the reaction temperature is 120° C., the catalytic efficiency is about 94%. Add 150ppm SO in the flue gas 2 and 8% H 2 After O, the catalytic efficiency was 88%.

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Abstract

The invention provides a preparation method of a selective catalytic reduction (SCR) catalyst Mn-Ce-M/TiO2 by removing NOx from flue gas, wherein M represents one or more of composite oxides, namely Fe, Co, Cu, Cr, Zr and Al, the molar ratio of the elements is Ti: Mn: Ce: M =1:(0.005-1):(0.005-1):(0-1). In the invention, an improved coprecipitation method is adopted, and an intermediate compound, namely titanium nitrate Ti(NO3)4 is taken as a precursor of TiO2, thus the influence of the other impurities in the precipitation process is overcome; by changing the dispersing homogeneous degree of MnOx and CeO2 on the surface of a carrier TiO2, the activity of the catalyst is improved and the temperature of the SCR reaction is reduced; by adjusting the preparation condition of the TiO2 precursor, the sulfur resistance and water resistance of the catalyst are improved completely; and by adding the elements, such as Fe, Co, Cu, Cr, Zr and Al and the like, the activity and resistance of the catalyst are further modified.

Description

technical field [0001] The invention relates to a method for preparing a low-temperature SCR catalyst for flue gas removal of NOx, especially a Mn-Ce / TiO-based catalyst with anti-sulfur dioxide and water performance 2 The preparation method of the low-temperature SCR catalyst of the system. Background technique [0002] Currently, using ammonia NH 3 As a reducing agent, selective catalytic reduction (SCR) NOx removal technology is the most widely used flue gas denitrification technology. NH 3 , NO and O 2 Oxidation-reduction reactions occur under the action of catalysts to generate N 2 and H 2 O. The catalyst used is mainly V 2 o 5 / TiO 2 series, it has very high catalytic activity, but it mainly has the following disadvantages in domestic applications: First, the reaction temperature is relatively high, and the general operating temperature is about 350 ° C. In order to meet the temperature requirements, the catalytic bed is generally arranged in the dust collector...

Claims

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Application Information

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IPC IPC(8): B01J23/34B01J23/889B01D53/90B01D53/56
CPCY02C20/10
Inventor 王忠渠刘健民曹沂胡宇峰王小明薛建明盛重义
Owner GUODIAN SCI & TECH RES INST
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