CN105618029A

CN105618029A - SCR (Selective Catalytic Reduction) denitration catalyst coated with rare earth and preparation method thereof

Info

Publication number: CN105618029A
Application number: CN201511015674.XA
Authority: CN
Inventors: 宋伟; 高春昱; 王正上; 穆世泉; 王新强; 陈华; 于宁; 王松; 孙静楠; 秦一鸣
Original assignee: QINGDAO HUADIAN ENVIRONMENTAL TECHNOLOGY Co Ltd
Current assignee: QINGDAO HUADIAN ENVIRONMENTAL TECHNOLOGY Co Ltd
Priority date: 2015-12-30
Filing date: 2015-12-30
Publication date: 2016-06-01

Abstract

The invention provides an SCR (Selective Catalytic Reduction) denitration catalyst coated with rare earth and a preparation method thereof. The SCR denitration catalyst coated with rare earth is characterized by consisting of the following components in parts by weight: 85-90 parts of titanium dioxide, 5-10 parts of cerium oxide, 1-4 parts of tungsten trioxide and 0.5-2 parts of lanthanum oxide. The preparation method is capable of reducing the influence of the SCR denitration catalyst coated with rare earth on environment and achieving a green environment-friendly design on the premise of basically keeping the denitration performance, sulfur dioxide oxidization rate and service life unchanged.

Description

The SCR denitration that rare earth is coated and its preparation method

Technical field

The present invention relates to environmental catalysis material, particularly relate to the coated SCR denitration of a kind of rare earth and its preparation method.

Background technology

Oxynitride not only can produce the environmental problem such as acid rain, photo-chemical smog, also HUMAN HEALTH can be caused disadvantageous effect. Therefore, the reduction of discharging of oxynitride is a very urgent problem with administering. With NH₃For the SCR technology (SCR) of reductive agent is the most effective industrial stationary source NOx removal method at present. The SCR denitration adopted at present is main active substances mainly with v element, but v element is dangerous objectionable impurities. Coal-burning power plant scraps the catalyzer got off and contains a large amount of v elements, does not have effective means effectively to be processed by this kind of spent catalyst at present, is main mainly with landfill. This generates soil pollution serious in a large number. The SCR denitration how designing the less environmental protection of a kind of environmental pollution is technical problem to be solved by this invention.

Summary of the invention

The SCR denitration that the present invention provides a kind of rare earth coated and its preparation method, realize when in guarantee denitration performance, oxidation rate of sulfur dioxide, work-ing life when substantially remaining unchanged, reduce the coated SCR denitration of rare earth to the pollution effect of environment, it is achieved environmental protection designs.

The SCR denitration that the present invention provides a kind of rare earth coated, composed of the following components according to parts by weight: titanium dioxide 85 ~ 90 parts; Cerium oxide 5 ~ 10 parts; Tungstic oxide 1 ~ 4 part; Lanthanum trioxide 0.5 ~ 2 part.

Further, composed of the following components according to parts by weight: titanium dioxide 88 parts, cerium oxide 8 parts, Tungsten oxide 99.999 3 parts, lanthanum trioxide 1 part.

The preparation method of the SCR denitration that the present invention also provides a kind of rare earth coated, the SCR denitration adopting above-mentioned rare earth coated, detailed process is:

Step 1, lanthanum nitrate, cerous nitrate and ammonium metawolframate are dissolved in deionized water respectively, obtain lanthanum nitrate hexahydrate, cerous nitrate solution and ammonium metatungstate solution;

Step 2, lanthanum nitrate hexahydrate and cerous nitrate solution are mixed with titanium dioxide;

Step 3, adjusted to ph 8-10, and it is settled out throw out;

Step 4, the throw out filtration in step 3, washing, dry, calcining;

Step 5, the material obtained in step 4 is added carboxymethyl cellulose ammonium mixes;

Step 6, material step 5 obtained are extruded and are formed carrier blank, then, obtain the coated SCR denitration of rare earth by after the drying of carrier blank, roasting.

Further, described step 4 is specially: drying temperature is 100 DEG C ~ 150 DEG C, and time of drying is 24 hours; Calcining temperature is 600 DEG C, and calcination time is 10 ~ 15 hours.

The SCR denitration that rare earth provided by the invention is coated and its preparation method, the surface of titanium dioxide can be coated on by Ce elements and lanthanum element, significantly increase active sites, simultaneously due to Tungsten oxide 99.999, cerium oxide, lanthanum trioxide coated, in calcination process, the grain growing of titanium dioxide receives effective suppression, make the specific surface area of catalyzer bigger, therefore activity under the same conditions has had compared with traditional catalyst and has improved largely, conversion rate of NOx, oxidation rate of sulfur dioxide all reaches requirement and (350 DEG C ~ 400 DEG C) denitration performance is better than traditional catalyst at a higher temperature, and, cerium oxide is nontoxic because having, the advantages such as the oxidation-reduction quality that reserves are abundant and excellent, and elemental cerium has unique electronic orbit 4f¹5d¹6s², at 5d¹Track only has an electronics, this kind of electronics arrangement causes transfer transport comparatively easy, without the need to adopting v element as active substance, realize when in guarantee denitration performance, oxidation rate of sulfur dioxide, work-ing life when substantially remaining unchanged, reduce the coated SCR denitration of rare earth to the pollution effect of environment, it is achieved environmental protection designs.

Embodiment

Embodiment one

1) cerous nitrate of 15.16kg is dissolved in the deionized water of 100kg; The ammonium metawolframate of 2.7kg is dissolved in the deionized water of 80kg; The lanthanum nitrate of 0.5kg is dissolved in the deionized water of 10kg;

2) joining in stirred pot by each solution dissolved, the titania powder adding 90kg stirs 1 hour;

3) in stirred pot, ammoniacal liquor is added gradually until pH equals 10 puts material and be settled out throw out;

4) throw out is put into whizzer and wash half an hour;

5) material is put into baking oven 110 DEG C of dryings 24 hours;

6) material is put into kiln 600 DEG C calcining 12 hours.

The ingredients weight parts of the SCR denitration that the rare earth that this example prepares is coated is: titanium dioxide 88 parts, cerium oxide 8 parts, Tungsten oxide 99.999 3 parts, lanthanum trioxide 1 part.

Embodiment two

1) cerous nitrate of 18.95kg is dissolved in the deionized water of 100kg; The ammonium metawolframate of 1.8kg is dissolved in the deionized water of 80kg; The lanthanum nitrate of 2kg is dissolved in the deionized water of 5kg;

2) each solution dissolved is joined in stirred pot, add the urea stirring and dissolving of 50kg;

3) titanium dioxide of 86kg is added, while stirring heating for dissolving tank to 80 DEG C;

4) the sulfuric acid adjustment pH to 10 slowly adding 0.5mol/L is put material and is settled out throw out;

5) throw out is put into whizzer and wash half an hour;

6) material is put into baking oven 110 DEG C of dryings 24 hours;

7) material is put into kiln 600 DEG C calcining 15 hours.

The ingredients weight parts of the SCR denitration that the rare earth that this example prepares is coated is: titanium dioxide 86 parts, cerium oxide 10 parts, Tungsten oxide 99.999 2 parts, lanthanum trioxide 2 parts.

Embodiment three

1) 200kg deionized water is joined in stirred pot;

2) add 91kg titanium dioxide in stirred pot, 11.37kg cerous nitrate, 1.8kg ammonium metawolframate, 1kg lanthanum nitrate, 2kg polyvinyl alcohol be stirred to and dissolve completely;

3) think stirred pot slowly to add ammoniacal liquor until pH puts material after equaling 10 is settled out throw out;

4) use deionized water water washing and precipitating thing, with pressure filter, moisture is extruded;

5) material is put into baking oven 110 DEG C of dryings 20 hours;

6) material is put into kiln 600 DEG C calcining 15 hours.

The ingredients weight parts of the SCR denitration that the rare earth that this example prepares is coated is: titanium dioxide 90 parts, cerium oxide 6 parts, Tungsten oxide 99.999 2 parts, lanthanum trioxide 2 parts.

The SCR denitration denitration activity test case that rare earth is coated:

Catalyzer prepared by above-mentioned 3 examples and tradition catalytic component based on vanadium (V₂O₅Content is 0.6 part, and catalyzer is 18 pore catalysts, length 1 meter) carry out test and comparison.

Test use equipment:

Specific surface area: Mike Mo Ruitike TriStar3020.

Catalyst performance is tested: electricity Qingdao green technology company limited of China pilot evaluating device.

Test condition is: temperature of reactor 350 DEG C, and flue gas condition is NO:600ppm, SO₂: 1000ppm, ammonia spraying amount: 600ppm, oxygen: 3%, water vapor: 7%, air speed: 3000, the catalyzer detection number of plies: 2 layers.

Comparative analysis:

1, tradition catalytic component based on vanadium: BET55 (m²/ g), denitration efficiency 98.6%, active 36.1, oxidation rate of sulfur dioxide 0.8%.

2, the catalyzer that embodiment one obtains: BET62 (m²/ g), denitration efficiency 97.2%, active 34.7, oxidation rate of sulfur dioxide 0.62%.

3, the catalyzer that embodiment two obtains: BET73 (m²/ g), denitration efficiency 98.4%, active 35.6, oxidation rate of sulfur dioxide 0.4%.

4, the catalyzer that embodiment two obtains: BET65 (m²/ g), denitration efficiency 97.8%, active 35.2, oxidation rate of sulfur dioxide 0.54%.

The SCR denitration that rare earth of the present invention is coated as can be seen here is under the prerequisite not using objectionable impurities v element, and its performance is basic and traditional catalyst is similar. In addition, the coated SCR denitration of rare earth its oxidation rate of sulfur dioxide compared with tradition vanadium base SCR denitration reduces close to 1 times, this just can alleviate in current power plant actual moving process the monoammonium sulfate phenomenon produced greatly, thus reduces the blocking of the upstream devices such as catalyzer duct and air preheater. Vanadium based denitration catalyst is while catalyzing N O gas and ammonia gas react generate nitrogen, and also the sulfurous gas in catalysis flue gas and oxygen reaction generate sulphur trioxide. The sulphur trioxide generated along with the carrying out of reaction gets more and more, the sulphur trioxide and ammonia and the water vapour that generate react generation monoammonium sulfate further, the viscosity of monoammonium sulfate is very high, attaching to the surface of catalyzer after lower than dew-point temperature, the micropore of blocking catalyst makes the active reduction of catalyzer. Oxidizing sulfur dioxide can be also sulphur trioxide by the coated catalyzer of rare earth, but reaction mechanism is different. Sulfurous gas through the coated catalyzer of rare earth, the Ce of catalyst surface⁴⁺To Ce³⁺Transform, oxidizing sulfur dioxide is become sulphur trioxide. Along with Ce³⁺Occur with the generation of oxygen vacancies, and Ce³⁺Charge unbalance can be caused with the existence of oxygen vacancies and bring out the generation of unsaturated chemical bond, so that rare earth coating layer oxygen defect or oh group increasing number. And chemically adsorbing oxygen for SCR reaction process reactive oxygen species transmission and activation all there is certain promoter action. And reach relatively stable state when the quantity of the oxygen defect in coating layer or hydroxy groups reaches just no longer to increase after to a certain degree, now just can not there is Ce through coating layer in sulfurous gas again⁴⁺To Ce³⁺Conversion, sulfurous gas can not be oxidized to sulphur trioxide and then cannot generate monoammonium sulfate.

Through the out of stock catalyzer of SCR that rare earth is coated, the oxide compound of cerium because the surface being distributed in crystal grain therefore can more fully with Gas phase Smoke mutual effect. Tradition catalytic component based on vanadium oxidation rate of sulfur dioxide is 0.8%, and the coated catalyzer oxidation rate of sulfur dioxide of three example middle-weight rare earths is respectively 0.62%, 0.4%, 0.54%. Detected result is fully demonstrating of above-mentioned reason.

Last it is noted that above embodiment is only in order to illustrate the technical scheme of the present invention, it is not intended to limit; Although with reference to previous embodiment to invention has been detailed description, it will be understood by those within the art that: the technical scheme described in foregoing embodiments still can be modified by it, or wherein part technology feature is carried out equivalent replacement; And these amendments or replacement, do not make the spirit and scope of the essence disengaging various embodiments of the present invention technical scheme of appropriate technical solution.

Claims

1. the SCR denitration that a rare earth is coated, it is characterised in that, composed of the following components according to parts by weight: titanium dioxide 85 ~ 90 parts; Cerium oxide 5 ~ 10 parts; Tungstic oxide 1 ~ 4 part; Lanthanum trioxide 0.5 ~ 2 part.

2. the SCR denitration that rare earth according to claim 1 is coated, it is characterised in that, composed of the following components according to parts by weight: titanium dioxide 88 parts, cerium oxide 8 parts, Tungsten oxide 99.999 3 parts, lanthanum trioxide 1 part.

3. the preparation method of the SCR denitration that a rare earth is coated, it is characterised in that, the SCR denitration adopting rare earth as claimed in claim 1 coated, detailed process is:

Step 3, adjusted to ph 8-10, and it is settled out throw out;

Step 4, the throw out filtration in step 3, washing, dry, calcining;

4. the preparation method of the SCR denitration that rare earth according to claim 3 is coated, it is characterised in that, described step 4 is specially: drying temperature is 100 DEG C ~ 150 DEG C, and time of drying is 24 hours; Calcining temperature is 600 DEG C, and calcination time is 10 ~ 15 hours.