Low-temperature ammonia selective oxidation catalyst

A catalytic oxidation and catalyst technology, applied in physical/chemical process catalysts, metal/metal oxide/metal hydroxide catalysts, inorganic chemistry, etc., can solve the problems of poor selectivity, low temperature window, high temperature window, etc. Achieve the effect of simple preparation process, convenient operation and stable activity

Active Publication Date: 2009-10-14
RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The temperature window of noble metal catalysts is low, but the preparation cost is high and the selectivity is not good, and it is easy to produce N 2 O by-product
Metal oxide catalysts and ion-exchanged zeolite-type catalysts have relatively good selectivity, but the temperature window is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Take 100 grams of gamma-alumina powder carrier (specific surface area: 250 square meters per gram), and slowly pour it into 500 milliliters of an aqueous solution in which 15.75 grams of silver nitrate and 30.97 grams of cerium nitrate are dissolved under continuous stirring. After stirring for 1 hour, the water was evaporated to dryness with a rotary evaporator, and dried overnight at 120°C. The dried catalyst was heated from room temperature to 600° C. at a rate of 10° C. per minute in an air atmosphere, and calcined at 600° C. for 3 hours. The 20-40 mesh particles were sieved for later use, that is, the catalyst of Example 1 was prepared. The prepared chemical composition is 10%Ag / 10%Ce / Al 2 o 3 oxidation catalyst.

Embodiment 2

[0016] Take 100 grams of gamma-alumina powder carrier (specific surface area: 250 square meters per gram), and slowly pour it into 500 milliliters of an aqueous solution in which 15.75 grams of silver nitrate is dissolved under continuous stirring. After stirring for 1 hour, the water was evaporated to dryness with a rotary evaporator, and dried overnight at 120°C. The dried catalyst was heated from room temperature to 600° C. at a rate of 10° C. per minute in an air atmosphere, and calcined at 600° C. for 3 hours. The granules of 20-40 mesh were sieved for later use, that is, the catalyst of Example 2 was prepared. The prepared chemical composition is 10%Ag / Al 2 o 3 oxidation catalyst.

Embodiment 3

[0018] Weigh 0.2 g of the catalyst of Example 1 and place it in a tubular fixed-bed reactor for reaction.

[0019] The reaction gas is simulated industrial ammonia pollution waste gas. Gas composition: the total flow rate of mixed gas is 200 ml per minute, of which, oxygen is 10%, ammonia is 500 ppm, and nitrogen is the balance gas. The reaction space velocity (GHSV) was 20,000 / hour for the catalyst. The reaction temperature range is from room temperature to 220°C. Ammonia and product concentrations were determined using an infrared gas cell.

[0020] The reaction results show that the conversion rate of ammonia exceeds 80% at 100°C; the conversion rate of ammonia is close to 100% at 120°C; and the conversion rate of ammonia reaches 100% at temperatures above 160°C.

[0021] Table 1 10%Ag / 10%Ce / Al 2 o 3 Catalyst Activity Evaluation Results

[0022]

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PUM

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Abstract

The invention provides a low-temperature ammonia selective oxidation catalyst which is used for eliminating ammonia gas pollution generated in the field of industry, agriculture, traffic, architecture, and the like, and selectively catalyzing and oxidizing the ammonia into pollution-free nitrogen and water under lower temperature. The oxidation catalyst can completely convert the ammonia under the temperature above 160 DEG C, and has the nitrogen selectivity of nearly 80 percent, good low-temperature oxidbillity, high catalytic efficiency and high stability. The oxidation catalyst contains porous inorganic oxide carrier, silver as an active component and cerium as an accessory ingredient, wherein the porous inorganic oxide carrier can be silicon dioxide, aluminium oxide, zirconia, lanthana, zinc oxide or titanium dioxide or the mixture of more than one of the oxide; the active component is formed by loading silver which a metal element with the weight conversion value of 1-15 percent on the inorganic oxide carrier; and the accessory ingredient is formed by simultaneously loading cerium and silver with the metal element weight conversion value of 5-50 percent on the inorganic oxide carrier.

Description

technical field [0001] The invention relates to a catalyst for eliminating ammonia pollution produced in processes such as industry, agriculture, transportation and construction, and selectively catalytically oxidizing ammonia into pollution-free nitrogen and water. When the oxidation catalyst is above 160 DEG C, the conversion rate of ammonia reaches 100%, and the nitrogen selectivity is close to 80%, which can effectively reduce the energy consumption in the process of eliminating ammonia pollution. technical background [0002] Ammonia pollution comes from a wide range of sources, including industrial sources (tail gas emissions during the production of liquid ammonia, ammonia leakage from ammonia selective reduction of nitrogen oxides); agricultural and animal husbandry sources; and concrete admixtures added in construction , wooden boards, interior decoration materials, indoor ammonia pollution caused by human and animal metabolites, etc. A low concentration of ammonia...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/66B01J23/50B01D53/86C01B21/02C01B5/00
Inventor 贺泓张丽张长斌
Owner RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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