阅读说明：本技术 一种锰基脱硝催化剂及其生产工艺 (Manganese-based denitration catalyst and production process thereof ) 是由 金猛 王阔 詹晓丹 李浙飞 沈刚峰 陈天德 陈洪锋 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种锰基脱硝催化剂及其生产工艺,该锰基脱硝催化剂包括活性助剂；催化剂活性组分前驱体；催化剂载体；去离子水；所述活性助剂为锰的氧化物,催化剂活性组分前驱体为质量浓度为50%的硝酸锰溶液；且活性助剂和催化剂活性组分前驱体中的锰元素负载量为3.2-12.6%；活性助剂为掺杂元素氧化物,所述掺杂元素包括铈、钴、铁中的一种；催化剂载体为二氧化钛。本发明中的锰基脱硝催化剂具有完整的外形以及优异的低温脱硝作用,且该锰基脱硝催化剂的生产工艺,使制备获得的锰基脱硝催化剂不易碎化且专门针对低温烟气(120-200℃)具有优异的脱硝效果。(The invention discloses a manganese-based denitration catalyst and a production process thereof, wherein the manganese-based denitration catalyst comprises an active auxiliary agent; a catalyst active component precursor; a catalyst support; deionized water; the active auxiliary agent is manganese oxide, and the precursor of the active component of the catalyst is a manganese nitrate solution with the mass concentration of 50%; the manganese element loading amount in the active auxiliary agent and the active component precursor of the catalyst is 3.2-12.6%; the active assistant is a doping element oxide, and the doping element comprises one of cerium, cobalt and iron; the catalyst support is titanium dioxide. The manganese-based denitration catalyst has a complete appearance and an excellent low-temperature denitration effect, and the manganese-based denitration catalyst prepared by the production process is not easy to break and has an excellent denitration effect specially for low-temperature flue gas (120 ℃ C.) (200 ℃ C.).)

1. The manganese-based denitration catalyst is characterized by comprising the following components:

a co-agent;

a catalyst active component precursor;

a catalyst support;

deionized water;

the active auxiliary agent is manganese oxide, and the precursor of the active component of the catalyst is a manganese nitrate solution with the mass concentration of 50%;

the manganese element loading amount in the active auxiliary agent and the active component precursor of the catalyst is 3.2-12.6%;

the active assistant is a doping element oxide, and the doping element comprises one of cerium, cobalt and iron;

the catalyst support is titanium dioxide.

2. The production process of a manganese-based denitration catalyst as set forth in claim 1, characterized by comprising the steps of:

the method comprises the following steps: mixing part of catalyst active component precursors and deionized water, diluting and obtaining an active aqueous solution;

step two: fully mixing a catalyst carrier and the rest of the catalyst active component precursor at the temperature of 60-70 ℃ to obtain a first mixture;

step three: fully mixing the coagent with the first mixture obtained in step two to form a second mixture;

step four: fully mixing the active aqueous solution obtained in the step one with the second mixture obtained in the step three to obtain a third mixture;

step five, kneading, filtering, molding and drying the third mixture obtained in the step four to obtain a primary finished product; then carrying out calcination treatment and cooling treatment, and cooling to 250 ℃ to obtain the manganese-based denitration catalyst;

in the fifth step, the calcination treatment comprises a calcination stage and a heat preservation stage, the calcination stage comprises a first calcination stage, a second calcination stage and a third calcination stage, and the calcination temperatures of the first calcination stage, the second calcination stage and the third calcination stage are gradually increased; the total time of the calcining treatment and the cooling treatment is 30-60 h;

during the calcination treatment, the used equipment is a mesh belt type calcination kiln, and the mesh belt speed is 0.7-1.6 m/h.

3. The production process of the manganese-based denitration catalyst according to claim 2, wherein the temperature of the first calcination stage is 25-150 ℃ for 4-6 h; the temperature of the second calcination stage is 150-250 ℃, and the time is 3-5 h; the temperature of the second calcination stage is 250-450 ℃, and the time is 4-6 h.

4. The production process of the manganese-based denitration catalyst according to claim 3, wherein the temperature rise rate of the first calcination stage is 2.08-4.17 ℃/min; the temperature rise speed of the second calcining stage is 1.67-3.33 ℃/min; the temperature rise speed of the third calcining stage is 3.33-6.67 ℃/min.

5. The production process of the manganese-based denitration catalyst according to claim 4, wherein in the fifth step, the heat preservation stage comprises a first heat preservation stage, a second heat preservation stage and a third heat preservation stage; the first heat preservation stage is positioned between the first calcination stage and the second calcination stage, the second heat preservation stage is positioned between the second calcination stage and the third calcination stage, and the third heat preservation stage is positioned after the third calcination stage; the heat preservation time of the first heat preservation stage, the second heat preservation stage and the third heat preservation stage is 4-6h respectively.

6. The production process of the manganese-based denitration catalyst according to claim 2, wherein the temperature reduction rate of the temperature reduction treatment is 18-24 ℃/h.

7. The production process of the manganese-based denitration catalyst according to claim 2, wherein in the fifth step, the temperature is 40-65 ℃ and the time is 12-16h in the drying process.

8. The production process of the manganese-based denitration catalyst according to claim 2, wherein in the calcination treatment process, the primary product is placed on the mat layer (1) to be calcined, and the mat layer (1) is a ceramic fiber layer.

9. The production process of the manganese-based denitration catalyst according to claim 8, wherein the mat layer (1) comprises a first mat layer (11) and a second mat layer (12), the first mat layer (11) and the second mat layer (12) are both provided with channels, the channels comprise first holes (2) and second holes (3), the maximum width of the second holes (3) is greater than the maximum width of the first holes (2), the second holes (3) on the first mat layer (11) are communicated with the second holes (3) on the second mat layer (12), and the mat layer (1) has a porosity of 45-55%.

10. The production process of the manganese-based denitration catalyst according to claim 8, wherein the surface of the cushion layer (1) in contact with the primary product is provided with an insulating layer, and the coverage rate of the insulating layer on the surface is 55-65%.

Technical Field

The invention relates to the technical field of SCR denitration catalysts, in particular to a manganese-based denitration catalyst and a production process thereof.

Background

The SCR technology is the most widely applied flue gas denitration technology at present, and the core of the SCR technology lies in a denitration catalyst. The existing commercial denitration catalyst mainly takes vanadium base, the using temperature is high, and the good denitration effect can be achieved within the range of 200-420 ℃. Once the temperature is lower than 200 ℃, the denitration effect of the denitration catalyst is poor, and the better denitration effect is difficult to realize. With the gradual increase of the application range of the SCR technology, the temperature of the flue gas in more and more industries is lower than 200 ℃, and for the flue gas with lower temperature (lower than 200 ℃), a catalyst capable of realizing better denitration function at low temperature is needed. Therefore, manganese-based denitration catalysts having excellent denitration performance at low temperatures (120-.

However, although there are many formulations of manganese-based denitration catalysts, the manganese-based denitration catalyst cannot maintain stable quality in the manufacturing process (mainly including the extrusion molding and calcination process), especially in the calcination process, and is prone to be broken, which limits the production and popularization of manganese-based denitration catalysts in practical applications.

Disclosure of Invention

In view of the disadvantages of the prior art, a first object of the present invention is to provide a manganese-based denitration catalyst having advantages of a complete shape and excellent low-temperature denitration.

The second purpose of the invention is to provide a production process of the manganese-based denitration catalyst, which has the advantages that the prepared manganese-based denitration catalyst is not easy to break and has excellent denitration effect specially for low-temperature flue gas.

In order to achieve the first object, the invention provides the following technical scheme:

a manganese-based denitration catalyst comprises the following components:

a co-agent;

a catalyst active component precursor;

a catalyst support;

deionized water;

the active auxiliary agent is manganese oxide, and the precursor of the active component of the catalyst is a manganese nitrate solution with the mass concentration of 50%;

the manganese element loading amount in the active auxiliary agent and the active component precursor of the catalyst is 3.2-12.6%;

the active assistant is a doping element oxide, and the doping element comprises one of cerium, cobalt and iron;

the catalyst support is titanium dioxide.

By adopting the technical scheme, the active auxiliary agent, the catalyst active component precursor, the catalyst carrier and the deionized water are matched together, the titanium dioxide has better adhesion, can provide better adhesion for the catalyst carrier, and the manganese element loading amount is 3.2-12.6%, so that the obtained manganese-based denitration catalyst can be suitable for denitration treatment at the temperature lower than 200 ℃.

More preferably: the titanium dioxide is anatase titanium dioxide.

By adopting the technical scheme, the anatase titanium dioxide is non-toxic and odorless, has high melting point, excellent chemical stability, light resistance, heat resistance and adhesion capacity, and is softer than the golden red titanium dioxide, so that better adhesion can be provided for the catalyst by using the anatase titanium dioxide.

In order to achieve the second object, the invention provides the following technical scheme:

a production process of a manganese-based denitration catalyst comprises the following steps:

the method comprises the following steps: mixing part of catalyst active component precursors and deionized water, diluting and obtaining an active aqueous solution;

step two: fully mixing a catalyst carrier and the rest of the catalyst active component precursor at the temperature of 60-70 ℃ to obtain a first mixture;

step three: fully mixing the coagent with the first mixture obtained in step two to form a second mixture;

step four: fully mixing the active aqueous solution obtained in the step one with the second mixture obtained in the step three to obtain a third mixture;

step five, kneading, filtering, molding and drying the third mixture obtained in the step four to obtain a primary finished product; then carrying out calcination treatment and cooling treatment, and cooling to 250 ℃ to obtain the manganese-based denitration catalyst;

in the fifth step, the calcination treatment comprises a calcination stage and a heat preservation stage, the calcination stage comprises a first calcination stage, a second calcination stage and a third calcination stage, and the calcination temperatures of the first calcination stage, the second calcination stage and the third calcination stage are gradually increased; the total time of the calcining treatment and the cooling treatment is 30-60 h;

the treatment speed is 0.7-1.6m/h during the calcination treatment.

By adopting the technical scheme, the calcining treatment comprises a calcining stage and a heat preservation stage, the adopted treatment speed is moderate and is 0.7-1.6m/h, the reaction in each calcining stage and each heat preservation stage is facilitated to be fully carried out, the mechanical strength of a product obtained in the calcining treatment process is not easily influenced, the product is kept to be good in integrity, and the phenomenon of fragmentation is not easily caused.

The holding stage is followed by a temperature reduction treatment, the temperature of which is still high in the preceding stage, in which case the residual manganese nitrate is sufficiently decomposed and the mechanical strength of the product obtained in the calcination stage is further increased. And the time of the temperature reduction treatment and the temperature reduction speed are kept in good balance, so that the situation that the mechanical strength of the product is adversely affected to cause the fragmentation of the molded product is not easy to occur. And the manganese nitrate in the system is just completely decomposed without residue, so that the obtained manganese-based denitration catalyst has excellent denitration performance at low temperature.

More preferably: the temperature of the first calcining stage is 25-150 ℃ and the time is 4-6 h; the temperature of the second calcination stage is 150-250 ℃, and the time is 3-5 h; the temperature of the second calcination stage is 250-450 ℃, and the time is 4-6 h.

Through adopting above-mentioned technical scheme, compare second calcination stage and third calcination stage, the temperature that the first calcination stage adopted is lower, mainly is used for getting rid of the manganese nitrate crystal water and preliminary decomposition manganese nitrate, and the time that the first calcination stage adopted is longer, helps fully getting rid of the manganese nitrate crystal water to also can decompose manganese nitrate better. The temperature in the second calcination stage is further increased in order to remove organic matters in the added components and further decompose manganese nitrate. The third calcining stage is to completely decompose the manganese nitrate and to make the product obtained by calcining in the third calcining stage have certain mechanical strength. The time adopted by the first calcining stage, the second calcining stage and the third calcining stage is more studied, and the data range is obtained according to the research of the applicant for many years, so that the function of each calcining stage can be played greatly.

More preferably: the temperature rise speed of the first calcining stage is 2.08-4.17 ℃/min; the temperature rise speed of the second calcining stage is 1.67-3.33 ℃/min; the temperature rise speed of the third calcining stage is 3.33-6.67 ℃/min.

By adopting the technical scheme, the temperature rise speed of the first calcining stage is higher, the time required by the temperature rise to reach the highest temperature of the first calcining stage is shortened, the calcining time under the highest temperature condition is longer, the crystal water in the manganese nitrate is removed fully, and the manganese nitrate is decomposed preliminarily. And the temperature rise speed of the second calcining stage tends to be gentle, so that the further decomposition of the manganese nitrate is further improved in the process, the internal structure of the primary finished product is gradually compacted, and the phenomenon of fragmentation is not easy to occur. If the temperature rise rate in the second calcination stage is too fast, the internal structure of the primary product cannot be well connected and is easily broken. The temperature rising speed of the third calcining stage is increased, so that the structure in the primary product calcined in the stage is further compacted, and the integrity is further improved.

More preferably: in the fifth step, the heat preservation stage comprises a first heat preservation stage, a second heat preservation stage and a third heat preservation stage; the first heat preservation stage is positioned between the first calcination stage and the second calcination stage, the second heat preservation stage is positioned between the second calcination stage and the third calcination stage, and the third heat preservation stage is positioned after the third calcination stage; the heat preservation time of the first heat preservation stage, the second heat preservation stage and the third heat preservation stage is 4-6h respectively.

By adopting the technical scheme, the first heat preservation stage, the second heat preservation stage and the third heat preservation stage are respectively matched with the first calcination stage, the second calcination stage and the third calcination stage, the three heat preservation stages respectively continue the highest temperatures of the first calcination stage, the second calcination stage and the third calcination stage, and the heat preservation time is longer than that of the calcination stage, so that the corresponding functions of the three calcination stages can be more fully exerted.

More preferably: the cooling speed of the cooling treatment is 18-24 ℃/h.

By adopting the technical scheme, the cooling speed is relatively slow, and in the cooling process, the initial product after the calcining stage and the heat preservation stage can be further subjected to high-temperature treatment at a higher temperature, so that the compactness among the components in the obtained manganese-based denitration catalyst is further improved.

More preferably: in the fifth step, the temperature is 40-65 ℃ and the time is 12-16h in the drying process.

Through adopting above-mentioned technical scheme, in the drying process, get rid of free water comparatively fully, be favorable to carrying out follow-up operation.

More preferably: in the calcining treatment process, the primary finished product is placed on a cushion layer for calcining, and the cushion layer is a ceramic fiber layer.

By adopting the technical scheme, the primary finished products are placed on the cushion layer to be processed at different temperature stages in the processes of calcining treatment and cooling treatment. The ceramic fiber layer has excellent high temperature resistance and is not easy to react with components in the catalyst. And the catalyst has a good heat-insulating effect, so that the time for the calcination stage and the heat-insulating stage to last the temperature of the corresponding stage is prolonged, and the overall performance of the obtained manganese-based denitration catalyst is further improved.

More preferably: the cushion layer comprises a first cushion layer and a second cushion layer, wherein channels are formed in the first cushion layer and the second cushion layer, each channel comprises a first hole and a second hole, the maximum width of each second hole is larger than that of each first hole, the second holes in the first cushion layer are communicated with the second holes in the second cushion layer, and the cushion layer has a porosity of 45-55%.

Through adopting above-mentioned technical scheme, be the bed course split into bed course and bed course down to stack bed course and bed course down, and the second hole intercommunication on second hole on the first bed course and the second bed course, two-layer stack back, the aperture that forms both ends is little, the big passageway in aperture of middle-end, has increased the inside surface area of passageway to a certain extent, has improved the effect of holding of hole to high temperature air, has also improved the heat preservation ability of bed course simultaneously. In the calcining treatment process, the heat conduction is carried out on the primary finished product contacted with the cushion layer through the heat transfer effect of the cushion layer; the heat preservation effect is realized to the heat preservation, makes the temperature difficult for rising too fast to be difficult for making the temperature in the first hole local too high, thereby to the primary product realization in every stage comparatively mild calcination effect.

The cushion layer contains a certain porosity, and the air with higher temperature passes through a channel formed by the first hole and the second hole in the cushion layer, so that the high-temperature air is not easy to excessively contact the primary finished product, the contact between the high-temperature air and the primary finished product is more uniform and fine, and the calcining effect of the primary finished product is more obvious. Meanwhile, crystal water in the primary finished product can be sufficiently removed, manganese nitrate and organic matters in the primary finished product can be sufficiently decomposed, the components in the primary finished product can be connected more tightly, and the mechanical strength of the obtained manganese-based denitration catalyst is improved to a certain extent.

More preferably: and the surface of the cushion layer, which is in contact with the primary finished product, is provided with a heat-insulating layer, and the coverage rate of the heat-insulating layer on the surface is 55-65%.

By adopting the technical scheme, the covering probability of the heat-insulating layer on the surface of the contact between the cushion layer and the primary finished product is 55-65%, wherein the pores are completely communicated or partially communicated or not communicated with the channels in the cushion layer, so that the heat of the heat-insulating layer is gradually transferred to the primary finished product through the heat-insulating layer to a certain extent, and meanwhile, the heat on the heat-insulating layer is also gradually transferred to the primary finished product. The arrangement of the heat-insulating layer is beneficial to improving the uniformity of the primary product during the calcination stage; in the heat preservation stage, the organic matter and the crystal water in the primary finished product can be further removed, and the manganese nitrate can be further decomposed. In the cooling treatment process, due to the heat preservation effect of the heat preservation layer, the temperature of the cushion layer is not easy to reduce too fast, but the required cooling speed can be kept.

In conclusion, the invention has the following beneficial effects:

firstly, in the application, the calcining treatment of the first calcining stage, the first heat preservation stage, the second calcining stage, the second heat preservation stage, the third calcining stage and the third heat preservation stage is adopted in sequence, the adopted treatment speed is moderate and is 0.7-1.6m/h, the full reaction in each calcining stage and each heat preservation stage is facilitated, the mechanical strength of a product obtained in the calcining treatment process is not easily influenced, the good integrity of the product is kept, and the fragmentation phenomenon is not easily caused.

Secondly, in the calcining stage, the temperature rising speed of the first calcining stage is higher, which is beneficial to shortening the time required by the temperature rising to be higher than the highest temperature of the stage, so that the calcining time under the highest temperature condition is longer, which is beneficial to fully removing crystal water in the manganese nitrate and carrying out primary decomposition on the manganese nitrate; the temperature rise speed of the second calcining stage tends to be relatively gentle, and in the process, the further decomposition of the manganese nitrate is further improved, so that the internal structure of the primary finished product becomes compact gradually, and the phenomenon of fragmentation is not easy to occur; the temperature rising speed of the third calcining stage is increased, so that the structure in the primary product calcined in the stage is further compacted, and the integrity is further improved.

Thirdly, the mild cooling speed is not easy to cause bad influence on the mechanical strength of the calcined primary product, and the removal of residual organic matters and manganese nitrate in the calcined primary product can be further promoted. The overall time of the calcination treatment and the temperature reduction treatment is shortened to a certain extent, the control effect is good, the quality and the mechanical strength of the obtained manganese-based denitration catalyst can be fully improved, the energy consumption can be effectively saved, and the sustainable development is facilitated.

Fourthly, in the processes of calcining and cooling, the primary finished product is placed on the cushion layer, which is beneficial to ensuring that the calcining effect of the primary finished product is more sufficient.

Fifthly, furtherly, with the bed course split into bed course and bed course down to stack bed course and bed course down, and the second hole intercommunication on second hole on the second bed course on the first bed course, two-layer stack back, the big passageway in aperture that the aperture of aperture that forms both ends is little, the middle-end has increased the inside surface area of passageway to a certain extent, has improved the effect of holding of hole to high temperature air, has also improved the heat preservation ability of bed course simultaneously. In the calcining treatment process, the heat conduction is carried out on the primary finished product contacted with the cushion layer through the heat transfer effect of the cushion layer; the heat preservation effect is realized to the heat preservation, makes the temperature difficult for rising too fast to be difficult for making the temperature in the first hole local too high, thereby to the primary product realization in every stage comparatively mild calcination effect.

Drawings

Fig. 1 is a schematic view of the structure of a mat layer employed in the present invention.

In the figure, 1, a cushion layer; 11. a first cushion layer; 12. a second cushion layer; 2. a first hole; 3. a second aperture.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples.