METHOD FOR PREPARING HIGH-EFFICIENCY DENITRIFICATION ACTIVITY CATALYST

Abstract

A method for preparing an active catalyst for high-efficiency denitration is disclosed. The method includes: a catalyst raw material is charged into a denitration reactor, NH.sub.3 and an inert gas are introduced and then heating is performed, and the temperature is held and then natural cooling is performed, thereby obtaining the catalyst. The active catalyst can greatly improve the denitration activity in low temperature range, and can not only improve the denitration efficiency under the condition without SO.sub.2 and H.sub.2O, but also can improve the denitration efficiency under the condition with both SO.sub.2 and H.sub.2O. The service life of the catalyst is prolonged under the premise of not changing the existing catalyst preparation process, and the economic benefit is significant. The denitration efficiency of a powder catalyst can be increased by 25%, and the denitration efficiency of a honeycombed catalyst or a corrugated catalyst can be increased by 20%.

Claims

1. A method for preparing an active catalyst for high-efficiency denitration, comprising: charging a catalyst product into a denitration reactor, introducing NH.sub.3 and an inert gas into the denitration reactor, heating the denitration reactor, holding a temperature of the denitration reactor, and cooling the denitration reactor naturally to obtain the active catalyst; wherein an active component of the catalyst product is selected from one or more oxides of Mo, W, Ce, Fe, Co, Ni, Cu, Nb, Sn, Mn or La, and a support is selected from one or more of titanium dioxide, titanium silicon powder, titanium tungsten powder, titanium tungsten silicon powder, silicon dioxide or aluminum oxide; and wherein the temperature is 300° C.-550° C., and a time of holding the temperature of the denitration reactor is 2 h-10 h.

2. (canceled)

3. The method for preparing the active catalyst for high-efficiency denitration according to claim 1, wherein the inert gas is one of helium or argon.

4. (canceled)

5. The method for preparing the active catalyst for high-efficiency denitration according to claim 1, wherein the active catalyst obtained is a powder catalyst, a honeycombed catalyst or a corrugated catalyst.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0011] The following describes the invention with reference to examples. Examples given are merely used for explaining the invention, and do not limit the scope of the invention.

Example 1

[0012] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0013] (1) A CoMnCeTiO.sub.2 honeycombed extruded catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0014] (2) NH.sub.3 and N.sub.2 were introduced, and the heating was started;

[0015] (3) the temperature was held at 300° C.-350° C. for 5 h-6 h;

[0016] (4) natural cooling was performed after the temperature holding was completed;

[0017] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+N.sub.2, GHSV=5000 h.sup.−1.

Example 2

[0018] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0019] (1) A VMoNiTiO.sub.2 honeycombed extruded catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0020] (2) NH.sub.3 and He were introduced, and heating was started;

[0021] (3) the temperature was held at 350° C.-400° C. for 3 h-4 h;

[0022] (4) natural cooling was performed after the temperature holding was completed;

[0023] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppmSO.sub.2+20% H.sub.2O+N.sub.2, GHSV=10000 h.sup.−1.

Example 3

[0024] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0025] (1) A VMoTiO.sub.2 powder catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0026] (2) NH.sub.3 and N.sub.2 were introduced, and the heating was started;

[0027] (3) the temperature was held at 450° C.-500° C. for 1 h-2 h;

[0028] (4) natural cooling was performed after the temperature holding was completed;

[0029] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppmSO.sub.2+20% H.sub.2O+N.sub.2, GHSV=50000 h.sup.−1.

Example 4

[0030] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0031] (1) A VWCeTiO.sub.2 powder catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0032] (2) NH.sub.3 and N.sub.2 were introduced, and the heating was started;

[0033] (3) the temperature was held at 400° C.-450° C. for 7 h-8 h;

[0034] (4) natural cooling was performed after the temperature holding was completed;

[0035] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppmSO.sub.2+20% H.sub.2O+N.sub.2, GHSV=80000 h.sup.−1.

Example 5

[0036] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0037] (1) A MnCeTiO.sub.2 powder catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0038] (2) NH.sub.3 and He were introduced, and heating was started;

[0039] (3) the temperature was held at 300° C.-350° C. for 9 h-10 h;

[0040] (4) natural cooling was performed after the temperature holding was completed;

[0041] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+N.sub.2, GHSV=100000 h.sup.−1.

Example 6

[0042] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0043] (1) A VWTiO.sub.2 honeycombed coated catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0044] (2) NH.sub.3 and N.sub.2 were introduced, and the heating was started;

[0045] (3) the temperature was held at 400° C.-450° C. for 2 h-3 h;

[0046] (4) natural cooling was performed after the temperature holding was completed;

[0047] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppmSO.sub.2+20% H.sub.2O+N.sub.2, GHSV=20000 h.sup.−1.

Example 7

[0048] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0049] (1) A VMoWTiO.sub.2 honeycombed coated catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0050] (2) NH.sub.3 and Ar were introduced, and heating was started;

[0051] (3) the temperature was held at 450° C.-500° C. for 8 h-9 h;

[0052] (4) natural cooling was performed after the temperature holding was completed;

[0053] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppmSO.sub.2+20% H.sub.2O+N.sub.2, GHSV=30000 h.sup.−1.

Example 8

[0054] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0055] (1) A VMoCeTiO.sub.2 corrugated catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0056] (2) NH.sub.3 and He were introduced, and heating was started;

[0057] (3) the temperature was held at 500° C.-550° C. for 4 h-6 h;

[0058] (4) natural cooling was performed after the temperature holding was completed;

[0059] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppmSO.sub.2+20% H.sub.2O+N.sub.2, GHSV=30000 h.sup.−1.

Example 9

[0060] A method for preparing an active catalyst for high-efficiency denitration, comprising the following steps:

[0061] (1) A VWCoTiO.sub.2 corrugated catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0062] (2) NH.sub.3 and N.sub.2 were introduced, and the heating was started;

[0063] (3) the temperature was held at 450° C.-500° C. for 1 h-2 h;

[0064] (4) natural cooling was performed after the temperature holding was completed;

[0065] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppmSO.sub.2+20% H.sub.2O+N.sub.2, GHSV=20000 h.sup.−1.

Comparative Example 1

[0066] A method for preparing a denitration catalyst, comprising the following steps:

[0067] (1) A TiO.sub.2 honeycombed coated catalyst was charged into a denitration reactor to test the denitration performance of a fresh sample;

[0068] (2) NH.sub.3 and N.sub.2 were introduced, and the heating was started;

[0069] (3) the temperature was held at 400° C.-450° C. for 2 h-3 h;

[0070] (4) natural cooling was performed after the temperature holding was completed;

[0071] (5) an activated sample was tested for denitration performance with the test conditions below: 500 ppmNO.sub.x+500 ppmNH.sub.3+10% O.sub.2+500 ppm SO.sub.2+20% H.sub.2O+N.sub.2, GHSV=20000 h.sup.−1.

[0072] The catalysts obtained in Examples 1-9 and Comparative Example 1 were tested for catalytic denitration effects at different temperatures, and the denitration efficiencies are shown in Table 1.

TABLE-US-00001 TABLE 1 Denitration efficiency at different temperatures Catalyst Denitration efficiency (%) Temperature (° C.) 180 200 250 300 350 400 Remark Example 1 55.6 68.7 76.5 84.3 90.6 87.1 Fresh sample 77.5 86.0 92.1 96.6 98.9 93.2 Activated sample Example 2 38.7 53.8 66.7 78.8 89.4 93.5 Fresh sample 63.7 74.0 84.4 92.5 97.1 99.0 Activated sample Example 3 33.9 57.7 73.7 87.2 95.9 98.9 Fresh sample 56.8 79.8 91.3 97.5 99.2 99.8 Activated sample Example 4 27.7 42.3 53.8 66.7 78.8 89.4 Fresh sample 55.4 68.6 79.4 88.8 94.9 98.1 Activated sample Example 5 49.3 68.2 82.1 92.6 98.1 93.5 Fresh sample 71.3 89.0 95.2 98.2 99.6 94.3 Activated sample Example 6 52.6 68.7 76.5 84.3 90.6 93.6 Fresh sample 69.8 85.9 93.8 95.6 96.8 97.0 Activated sample Example 7 40.2 58.5 73.3 81.9 88.5 92.1 Fresh sample 64.5 80.8 92.7 94.5 95.1 97.1 Activated sample Example 8 39.6 56.3 68.3 80.0 87.7 92.3 Fresh sample 58.6 73.9 85.6 91.5 94.7 95.6 Activated sample Example 9 46.3 65.9 78.9 84.0 91.1 92.7 Fresh sample 65.6 79.9 88.3 92.7 96.3 97.2 Activated sample Comparative 3.0 3.5 3.9 3.9 4.1 4.3 Fresh example 1 sample 3.2 3.6 3.8 4.0 4.2 4.4 Activated sample

[0073] It can be seen from the test results in Table 1 that the denitration efficiencies of all the catalysts of Examples 1-9 are increased after calcination and activation, and that with the increase of the test temperature, the differences between the activated samples and the fresh samples are reduced, and when the test temperature is 180° C., the differences between the two are the largest (15%-30%), indicating that the method provided by the invention can greatly improve the denitration activity of the catalyst in low temperature range.

[0074] Comparative Example 1 has no active component with TiO.sub.2 as the support, the fresh sample and the activated sample have similar denitration efficiencies, and the denitration efficiencies at 180° C.-400° C. are less than 5%, indicating that the method provided by the invention cannot improve the denitration activity of the support.

[0075] The above-mentioned descriptions are merely preferred embodiments of the invention but not intended to limit the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the invention should be included within the scope of protection of the present solution.