CN-122006704-A - Water-resistant manganese-based ultralow-temperature particle denitration catalyst based on hydrophobic flaky substrate and preparation method thereof

CN122006704ACN 122006704 ACN122006704 ACN 122006704ACN-122006704-A

Abstract

The invention discloses a hydrophobic flaky substrate-based water-resistant manganese-based ultralow-temperature particle denitration catalyst and a preparation method thereof, wherein the preparation method comprises the steps of ball-milling, mixing, drying and grinding a hydrophobic agent and manganese-based catalyst powder to obtain hydrophobic composite powder; extruding the prepared hydrophobic composite powder into slices by an internal mixer and/or a high-temperature roller press to form a slice-shaped catalyst base material, adding a forming auxiliary agent into the prepared slice-shaped catalyst base material, uniformly mixing by adopting mechanical stirring equipment, extruding and tabletting the prepared mixture by a high-pressure granule tablet press to form the water-resistant manganese-based ultra-low-temperature granule denitration catalyst granules with the structural characteristics of the slice-shaped base material. According to the preparation method of the water-resistant manganese-based ultralow-temperature particle denitration catalyst based on the hydrophobic sheet-shaped substrate, the water-resistant manganese-based ultralow-temperature particle denitration catalyst prepared by the preparation method is high in water resistance, high in sulfur resistance and high in mechanical strength.

Inventors

XU YUN
ZHANG CHUNLEI
ZHUANG KE
ZHANG QIAN
ZHOU KAI
ZHOU PING
Peng Weini
LI CHANGMING
YU JIAN

Assignees

国家能源集团科学技术研究院有限公司
中国科学院过程工程研究所

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (10)

1. The preparation method of the water-resistant manganese-based ultralow-temperature particle denitration catalyst based on the hydrophobic flaky substrate is characterized by comprising the following steps of: Step (1), preparing hydrophobic composite powder, namely ball-milling and mixing a hydrophobic agent and manganese-based catalyst powder, drying and grinding to obtain the hydrophobic composite powder; Step (2), preparing a flaky catalyst substrate, namely extruding the hydrophobic composite powder prepared in the step (1) into a tablet through an internal mixer and/or a high-temperature roller press to form the flaky catalyst substrate; Step (3) of preparing a mixture body, namely adding a forming auxiliary agent into the flaky catalyst base material prepared in the step (2), and uniformly mixing by adopting mechanical stirring equipment; and (4) preparing the water-resistant manganese-based ultralow-temperature particle denitration catalyst, namely extruding and tabletting the mixture prepared in the step (3) by a high-pressure particle tablet press to form the water-resistant manganese-based ultralow-temperature particle denitration catalyst particles with the structural characteristics of the flaky substrate.
2. The preparation method of claim 1, wherein the hydrophobizing agent in the step (1) comprises at least one of fluorinated polymer, silane coupling agent, two-dimensional lamellar carbon material, graphite and carbon nano tube, wherein the fluorinated polymer is polytetrafluoroethylene or polyvinylidene fluoride, the two-dimensional lamellar carbon material is graphene or graphene oxide, and the mass ratio of the hydrophobizing agent in the hydrophobic composite powder is 2% -15%.
3. The preparation method of claim 1, wherein the manganese-based catalyst powder in the step (1) is obtained by taking manganese cerium or manganese samarium as a raw material and roasting and crushing, and the mass ratio of the manganese-based catalyst powder in the hydrophobic composite powder is 85% -98%.
4. The method according to claim 1, wherein in the grinding treatment of step (1), a sand mill or a high-energy nano-mill is used, the grinding medium is zirconia microbeads, and the particle size D50 of the obtained composite powder is 1-10 μm.
5. The method according to claim 1, wherein in the extrusion sheet of step (2), the hydrophobic composite powder is extruded by an internal mixer and/or a high Wen Yagun machine into the sheet-shaped catalyst base material having a thickness of 0.1 to 2mm, a length of 5 to 20mm, and a width of 5 to 20mm at a temperature of 25 to 450 ℃ at a rotation speed of 50 to 100rpm and a pressure of 5 to 60 MPa.
6. The method of claim 1, wherein the forming aid in step (3) comprises glass fibers comprising at least one of chopped glass fibers, glass fiber powder, and glass mat, and/or clay comprising at least one of bentonite, kaolin, and montmorillonite.
7. The method according to claim 1, wherein in the step (3), the mass ratio of the molding aid in the mixture is 1% -10%, and the minimum size of the sheet structure of the mixed material is not less than 2 mm.
8. The preparation method according to claim 1, wherein the uniform mixing process in the step (3) is performed by mechanochemical compounding treatment in a ball mill under the protection of inert atmosphere, wherein the ball milling speed is 300-500 rpm, the mass ratio of grinding balls to materials is (6-15): 1, and the treatment time is 2-6 h.
9. The method according to claim 1, wherein the tabletting in the step (4) is to extrude the mixture under a pressure of 10-200 MPa to obtain the water-resistant manganese-based ultra-low temperature particle denitration catalyst with a diameter of 5-9 mm, a length of 8-12 mm and a compressive strength of not less than 60N/particle.
10. A hydrophobic sheet substrate-based water-resistant manganese-based ultra-low temperature particulate denitration catalyst, characterized in that the hydrophobic sheet substrate-based water-resistant manganese-based ultra-low temperature particulate denitration catalyst is prepared by the preparation method according to any one of claims 1 to 9.

Description

Water-resistant manganese-based ultralow-temperature particle denitration catalyst based on hydrophobic flaky substrate and preparation method thereof Technical Field The invention relates to the technical field of flue gas denitration catalytic materials, in particular to a water-resistant manganese-based ultralow-temperature particle denitration catalyst based on a hydrophobic flaky substrate and a preparation method thereof. Background Nitrogen oxides (NO x) are one of the main sources of atmospheric pollution, and emission control has become an important point for environmental protection. Selective Catalytic Reduction (SCR) technology is the most widely used and most mature flue gas denitration means at present, and its technical economy is highly dependent on catalyst performance. In recent years, manganese-based catalysts are recognized as the most potential low-temperature SCR replacement system due to the rich variable valence of manganese oxide, excellent low-temperature redox capability and rich surface oxygen vacancies. The existing researches show that the Mn-based catalyst such as MnO x, mn-Ce, mn-Sm and the like can realize the NO x removal efficiency of more than 90% in a low temperature region. However, manganese-based catalysts face three common bottlenecks in facing industrial applications, namely poor water resistance, poor sulfur resistance, and low mechanical strength. Particularly, in ultralow-temperature and high-humidity flue gas (H 2 O content is often 8% -30%), water molecules, NH 3 and NO are subjected to strong competitive adsorption at active sites, SO that the activity cliff type is reduced, SO 2 reacts with active components to generate MnSO 4 with extremely high thermal stability to cause irreversible inactivation, and reacts with NH 3 to generate ammonium bisulfate to cover the surface of a catalyst and block pore channels, the compressive strength of the traditional powder or granular catalyst is generally lower than 40N/granule, and the traditional powder or granular catalyst is easy to crush and pulverize under high-speed flue gas flushing, SO that the requirements of the ultralow-temperature and high-humidity working condition long-period stable operation of industrial devices are difficult to be met. Therefore, the manganese-based catalyst in the related art has problems of poor water resistance, weak sulfur resistance, and low mechanical strength, and needs to be improved. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, one purpose of the invention is to provide a preparation method of the water-resistant manganese-based ultralow-temperature particle denitration catalyst based on the hydrophobic flaky substrate, wherein the water-resistant manganese-based ultralow-temperature particle denitration catalyst prepared by the preparation method has strong water resistance, strong sulfur resistance and high mechanical strength. The invention also provides a water-resistant manganese-based ultralow-temperature particle denitration catalyst based on the hydrophobic flaky substrate, which is prepared by the preparation method. According to an embodiment of the invention, the preparation method of the hydrophobic flaky substrate-based water-resistant manganese-based ultralow-temperature particle denitration catalyst is characterized by comprising the following steps of: Step (1), preparing hydrophobic composite powder, namely ball-milling and mixing a hydrophobic agent and manganese-based catalyst powder, drying and grinding to obtain the hydrophobic composite powder; Step (2), preparing a flaky catalyst substrate, namely extruding the hydrophobic composite powder prepared in the step (1) into a tablet through an internal mixer and/or a high-temperature roller press to form the flaky catalyst substrate; Step (3) of preparing a mixture body, namely adding a forming auxiliary agent into the flaky catalyst base material prepared in the step (2), and uniformly mixing by adopting mechanical stirring equipment; and (4) preparing the water-resistant manganese-based ultralow-temperature particle denitration catalyst, namely extruding and tabletting the mixture prepared in the step (3) by a high-pressure particle tablet press to form the water-resistant manganese-based ultralow-temperature particle denitration catalyst particles with the structural characteristics of the flaky substrate. According to the preparation method of the water-resistant manganese-based ultralow-temperature particle denitration catalyst based on the hydrophobic flaky substrate, continuous three-dimensional hydrophobic networks are built on the surface and inside of the catalyst through the combination of the hydrophobic agent and the manganese-based catalyst powder, the crossing of the manganese-based catalyst from 'surface layer hydrophobicity' to 'integral hydrophobicity' is realized, the durability of the water resistance