CN102553572A - Selective catalytic reduction (SCR) catalyst of wide active temperature window and preparation method thereof - Google Patents

Abstract

The invention provides a selective catalytic reduction (SCR) catalyst of a wide active temperature window, which is used for removing nitre for a fixed source and a moving source. The invention further provides a preparation method of the catalyst. The catalyst adopts anatase type titanium dioxide to serve as a carrier and adopts cerium oxide and manganese oxide as active components, the content of the cerium oxide counts for 1-20% of the content of the catalyst by mass percentage, and the content of the manganese oxide counts for 1-20% of the content of the catalyst by mass percentage. The SCR catalyst of the wide active temperature window adopts the anatase type titanium dioxide to serve as the carrier, adopts the oxide of cerium and manganese to serve as the active components, does not adopt an active component of vanadium pentoxide (V2O5) with toxicity so as to reduce pollution to the environment, has the performance for catalysis and purificatioin of nitric oxide with high efficiency in the wide active temperature window, and meets the requirements of strict emission regulations. In a range from 200 DEG C to 500 DEG C, the removing rate of the nitric oxide can reach 90% above. The catalyst can be used for purifying and treating the nitric oxide in waste gas discharged by the fixed source and the moving source and can be used for treating diesel vehicle tail gas nitric oxide (NOx) and used in a nitre-removing device for removing the nitre in a fixed source coal-fired power plant.

Description

A kind of SCR Catalysts and its preparation method of wide active temperature windows

Technical field

The present invention relates to catalyst technical field, relate in particular to a kind of SCR Catalysts and its preparation method of wide active temperature windows, specifically is that the cerium manganese titanium of wide active temperature windows is the SCR catalyst.

Technical background

Along with the increase day by day of development of modern industry and automobile quantity, the human NOx that in atmosphere, discharges is more and more, and NOx pollutes has become a serious day by day global problem.NOx comprises NO, NO as one of atmosphere major pollutants ₂, N ₂O, N ₂O ₃And N ₂O ₄Deng, mainly with NO and NO ₂Form exist, wherein NO accounts for 95% of NOx total amount.The whole world enters the combustion process that derives from fossil fuels such as coal, oil, natural gas more than 90% among the NOx of atmosphere every year.It can cause greenhouse effects, depletion of the ozone layer and acid rain to form.

The NOx emission control is divided into stationary source denitrating flue gas and moving source NOx emission control.China is maximum in the world coal production and consumption state, also is that a few is one of country of main energy sources (coal accounts for more than 70% of primary energy) with coal in the world.Expectation is in 50 years from now on, and China is that main energy resource structure marked change can not take place with coal.The primary energy structures shape of this uniqueness coal-fired thermal power generation at the medium-term and long-term dominate of China power industry, this has just determined the coal-burning power plant is that main stationary source NOx emission control is still the main aspect that China administers NOx.In addition, the fast development of China's automotive industry has in recent years also brought the tail gas pollution of motor-driven vehicle problem that becomes increasingly conspicuous, and diesel vehicle NOx emission control also will be one of Future in China NOx emission control key content.

At present, (Selective Catalytic Reduction SCR) is regarded as NOx catalytic purification one of effective method the most to the SCR technology.Its principle is under the effect of catalyst, through adding the N that appropriate reductant optionally is reduced to NOx nonhazardous ₂, realize the NOx catalytic eliminating, wherein the SCR of ammonia is to use gas denitrifying technology the most widely, and is regarded as and is hopeful to be applied to one of large diesel engine tail gas NOx purification techniques most.

The core of SCR technology is the catalyst that exploitation has high activity, thermally-stabilised and good durability, and being studied maximum is noble metal, metal oxide and molecular sieve catalyst, wherein, and with V ₂O ₅For the catalytic component based on vanadium of active component demonstrates catalytic performance preferably, and successfully drop into commercial application, this catalyst has advantages of high catalytic activity at 300-400 ℃, and has anti-preferably H ₂O and SO ₂Poisoning performance.But also there is certain problem in this catalyst: the one, and temperature window is narrow, only in 300-400 ℃ of scope, has greater activity, and low temperature active is poor; The 2nd, high-temperature selective and poor heat stability, accessory substance N during high temperature ₂O growing amount showed increased; The 3rd, a large amount of uses of vanadium are all unfavorable to health and environment.

Summary of the invention

In order to overcome the problems referred to above that exist in the prior art; The SCR catalyst that the purpose of this invention is to provide a kind of wide active temperature windows; Be used for fixing source and moving source denitration; Have the wide characteristics of avirulence and active temperature windows, it can realize that efficient catalytic removes nitrogen oxide in 200-500 ℃ of temperature range.

Another object of the present invention provides above-mentioned wide active temperature windows SCR Preparation of catalysts method.

The SCR catalyst of wide active temperature windows of the present invention; With the anatase titanium dioxide is that carrier, cerium oxide and manganese oxide are active component; Wherein cerium oxide and manganese oxide account for the 1-20% of catalyst quality respectively, and all the other 60-98% are the carrier anatase titanium dioxide.

Said cerium oxide adds with the form of the water-soluble salt of cerium, and manganese oxide adds with the water-soluble salt form of manganese.Preferably: said cerium oxide adds with the form of cerous nitrate or cerous acetate, and said manganese oxide adds with the form of manganese nitrate or manganese acetate.

Preparation of catalysts method of the present invention is carried out according to the following steps:

1) respectively cerium salt and manganese salt are dissolved in the deionized water, wherein cerium salt calculates the 1-20% that accounts for the catalyst gross mass with cerium oxide, and manganese salt calculates the 1-20% that accounts for the catalyst gross mass with manganese oxide, then both is mixed;

2) with Detitanium-ore-type TiO ₂Powder impregnation is in above-mentioned cerium manganese mixed solution, and it accounts for the 60-98% of catalyst gross mass;

3) stir 0.5-2h, 70-90 ℃ is stirred evaporate to dryness down then, places 100 ℃ of baking ovens oven dry to spend the night, roasting 3-5h in the 400-600 ℃ of air, after the grinding the SCR catalyst of wide active temperature windows.

Described cerium salt is selected from cerous nitrate or cerous acetate, and manganese salt is selected from manganese nitrate or manganese acetate.

Catalyst of the present invention is carrier with the anatase titanium dioxide, is active component with the cerium Mn oxide, does not adopt virose active component V ₂O ₅, alleviated pollution to environment, possessed the performance of efficient catalytic purifying nitrogen oxide in than wide active temperature windows, adapt to stricter emission regulation demands, in 200-500 ℃ of scope, removal efficiency of nitrogen oxides reaches more than 90%.This catalyst can be used for the nitrogen oxide in purified treatment stationary source and the moving source exhaust gas discharged, like the denitrification apparatus of exhaust gas from diesel vehicle NOx processing and stationary source coal-burning power plant.

Description of drawings

Fig. 1 adopts catalyst of the present invention that the typical component mist is carried out catalytic reduction graph of a relation between removal of nitrogen oxide rate and the temperature when handling.

The specific embodiment

Below in conjunction with embodiment the present invention is further specified:

The titanium dioxide that the present invention uses is homemade anatase titanium dioxide.The cerium salt that uses is cerous nitrate or cerous acetate, and the manganese salt that uses is manganese nitrate or manganese acetate.

Embodiment one

2.5227g six water cerous nitrates are dissolved in the 500ml deionized water, again 2.8191g four water acetic acid manganese are dissolved in the 500ml deionized water, two parts of solution stirring are mixed obtain solution A then.Take by weighing the 98g anatase titanium dioxide then and impregnated in the solution A, stir 2h.Stir down evaporates to dryness at 80 ℃ then, and in 100 ℃ of baking ovens dried overnight.500 ℃ of roasting 5h in Muffle furnace then, after the grinding cerium manganese content is respectively the SCR catalyst of 1% wide active temperature windows.

Embodiment two

25.2272g six water cerous nitrates are dissolved in the 500ml deionized water, again 28.1905g four water acetic acid manganese are dissolved in the 500ml deionized water, two parts of solution stirring are mixed obtain solution A then.Take by weighing the 80g anatase titanium dioxide then and impregnated in the solution A, stir 2h.Stir down evaporates to dryness at 80 ℃ then, and in 100 ℃ of baking ovens dried overnight.500 ℃ of roasting 5h in Muffle furnace then, after the grinding cerium manganese content is respectively the SCR catalyst of 10% wide active temperature windows.

Embodiment three

50.4544g six water cerous nitrates are dissolved in the 500ml deionized water, again 56.3810g four water acetic acid manganese are dissolved in the 500ml deionized water, two parts of solution stirring are mixed obtain solution A then.Take by weighing the 60g anatase titanium dioxide then and impregnated in the solution A, stir 2h.Stir down evaporates to dryness at 80 ℃ then, and in 100 ℃ of baking ovens dried overnight.500 ℃ of roasting 5h in Muffle furnace then, after the grinding cerium manganese content is respectively the SCR catalyst of 20% wide active temperature windows.

Embodiment four

2.3652g five water acetic acid ceriums are dissolved in the 500ml deionized water, again 2.8871g four water manganese nitrates are dissolved in the 500ml deionized water, two parts of solution stirring are mixed obtain solution A then.Take by weighing the 98g anatase titanium dioxide then and impregnated in the solution A, stir 2h.Stir down evaporates to dryness at 80 ℃ then, and in 100 ℃ of baking ovens dried overnight.500 ℃ of roasting 5h in Muffle furnace then, after the grinding cerium manganese content is respectively the SCR catalyst of 1% wide active temperature windows.

Embodiment five

23.6516g five water acetic acid ceriums are dissolved in the 500ml deionized water, again 28.8714 4 water manganese nitrates are dissolved in the 500ml deionized water, two parts of solution stirring are mixed obtain solution A then.Take by weighing the 80g anatase titanium dioxide then and impregnated in the solution A, stir 2h.Stir down evaporates to dryness at 80 ℃ then, and in 100 ℃ of baking ovens dried overnight.500 ℃ of roasting 5h in Muffle furnace then, after the grinding cerium manganese content is respectively the SCR catalyst of 10% wide active temperature windows.

Embodiment six

47.3032g five water acetic acid ceriums are dissolved in the 500ml deionized water, again 57.7428g four water manganese nitrates are dissolved in the 500ml deionized water, two parts of solution stirring are mixed obtain solution A then.Take by weighing the 60g anatase titanium dioxide then and impregnated in the solution A, stir 2h.Stir down evaporates to dryness at 80 ℃ then, and in 100 ℃ of baking ovens dried overnight.500 ℃ of roasting 5h in Muffle furnace then, after the grinding cerium manganese content is respectively the SCR catalyst of 20% wide active temperature windows.

Catalytic activity detects

The 1ml catalyst sample of in fixed bed reactors, packing into, and reactor put into heating furnace; Feed the NOx of 1000ppm, the NH of 1000ppm ₃And 5%O ₂, nitrogen is as balance gas, and air speed is 48000h ^-1, purge under the room temperature and stablize 1h.Be warming up to the design temperature point, behind the stable reaction 1h, through flue gas analyzer, gather concentration data, and calculate at the NOx of this temperature spot conversion ratio.In 150-500 ℃ of (50 ℃ are the interval) temperature range, catalyst is carried out activity rating.The removal of nitrogen oxide rate of typical catalyst sample and the relation of temperature are as shown in Figure 1.As can beappreciated from fig. 1, in 250-450 ℃ of temperature range, the removal efficiency of NOx can reach more than 90%, and 300-400 ℃ temperature window than traditional catalyst has lifting by a relatively large margin, can better satisfy the needs of practical application.

Claims (5)

1. the SCR catalyst of a wide active temperature windows; It is characterized in that; This catalyst is carrier with the anatase titanium dioxide; Cerium oxide and manganese oxide are active component, and cerium oxide content is the 1-20% of catalyst quality percentage composition, and manganese oxide content is the 1-20% of catalyst quality percentage composition.

2. the SCR catalyst of wide active temperature windows as claimed in claim 1 is characterized in that, said cerium oxide adds with the form of the water-soluble salt of cerium, and manganese oxide adds with the water-soluble salt form of manganese.

3. according to claim 1 or claim 2 the SCR catalyst of wide active temperature windows is characterized in that said cerium oxide adds with the form of cerous nitrate or cerous acetate, and said manganese oxide adds with the form of manganese nitrate or manganese acetate.

4. the SCR Preparation of catalysts method of the described wide active temperature windows of claim 1 is characterized in that this method is carried out according to the following steps:

1) respectively cerium salt and manganese salt are dissolved in the deionized water, wherein cerium salt calculates the 1-20% that accounts for the catalyst gross mass with cerium oxide, and manganese salt calculates the 1-20% that accounts for the catalyst gross mass with manganese oxide, then both is mixed;

2) with Detitanium-ore-type TiO ₂Powder impregnation is in above-mentioned cerium manganese mixed solution, and it accounts for the 60-98% of catalyst gross mass;

3) stir 0.5-2h, 70-90 ℃ is stirred evaporate to dryness down then, places 100 ℃ of baking ovens oven dry to spend the night, roasting 3-5h in the 400-600 ℃ of air, after the grinding the SCR catalyst of wide active temperature windows.

5. preparation method according to claim 4 is characterized in that described cerium salt is selected from cerous nitrate or cerous acetate, and manganese salt is selected from manganese nitrate or manganese acetate.

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