CN-122006690-A - Composite pore-forming agent of denitration catalyst and application thereof

CN122006690ACN 122006690 ACN122006690 ACN 122006690ACN-122006690-A

Abstract

The invention discloses a composite pore-forming agent of a denitration catalyst, which consists of finished methyl cellulose and polystyrene. Meanwhile, the invention also discloses a method for preparing the titanium dioxide porous ceramic carrier with high specific surface area by adopting the composite pore-forming agent. The invention utilizes the difference of two materials of finished methyl cellulose (CMC) and Polystyrene (PS) in corresponding proportion in the composite catalyst in temperature response and physical state, realizes the decomposition in a stepped way, completes the construction of a multistage pore structure, and remarkably improves the catalytic efficiency of the carrier.

Inventors

TENG YE
LI DINGHUI
WU YANJUAN
WU YANBIN

Assignees

福建钒钛科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260320

Claims (6)

1. A composite pore-forming agent of a denitration catalyst is characterized by comprising finished methyl cellulose and polystyrene.
2. A composite pore-forming agent for a denitration catalyst as claimed in claim 1, wherein the mass ratio of the finished methylcellulose to the polystyrene is 1:2 to 1:5.
3. A method for preparing a titanium dioxide porous ceramic carrier with high specific surface area by adopting the composite pore-forming agent as claimed in claim 1, which is characterized by comprising the following specific steps: Firstly, batching, namely screening titanium dioxide and composite pore-forming agent powder through a 200-mesh screen respectively to obtain a batching for preparation; adding a pore-forming agent, taking the titanium dioxide powder screened in the step one as a base material, and then adding the pore-forming agent powder screened in the step one into the titanium dioxide powder for uniform mixing, wherein the mass ratio of the pore-forming agent powder to the titanium dioxide powder is 1:2-1:5, so as to obtain a mixed ingredient; Step three, kneading and mixing, namely putting the mixed ingredients obtained in the step two into a kneader, adding distilled water, and kneading and mixing for 5 hours to obtain evenly mixed pug; step four, filling a sealed tank for aging, and putting the pug obtained in the step three into the sealed tank for aging for 24 hours; step five, molding the green blank, taking out the aged pug, then putting the pug into a ceramic tube extruder, controlling the extrusion pressure to be 10MPa, and extruding to obtain the green blank; step six, drying the green embryo, namely putting the formed green embryo into an electric heating drying oven for drying, and taking out the dried green embryo after the drying is finished to obtain a dried green embryo; And seventhly, calcining and decomposing, namely placing the dried green blank obtained in the step six into an electric furnace, and continuously calcining for 8 hours to obtain the titanium dioxide porous ceramic carrier with the pore structure.
4. A method for preparing a porous titanium dioxide ceramic carrier with a high specific surface area according to claim 3, wherein the sixth step comprises the specific steps of firstly adjusting the temperature of an electric heating drying oven to 40 ℃, drying for 120 hours, then raising the temperature of the electric heating drying oven to 50 ℃, continuing to dry for 120 hours, raising the temperature of the electric heating drying oven to 60 ℃ again after 120 hours, and continuing to dry for 72 hours to obtain a dried green body.
5. A method for producing a titania porous ceramic support having a high specific surface area according to claim 3, wherein in the seventh step, the electric furnace is raised to 600℃at a temperature raising rate of 5℃per minute, and calcination is carried out continuously for 8 hours.
6. The method of claim 3, wherein in the fifth step, a single cylindrical structure with an outer diameter of 3mm and a length of 1cm is obtained by extrusion.

Description

Composite pore-forming agent of denitration catalyst and application thereof Technical Field The invention relates to the field of denitration catalyst materials, in particular to a composite pore-forming agent of a denitration catalyst and application thereof. Background With the rapid development of industrial economy, nitrogen oxides (NOx) are one of the main atmospheric pollutants, causing serious harm to the ecological environment and human health. The Selective Catalytic Reduction (SCR) technology is the most widely used and most efficient flue gas denitration technology at present, and the core of the technology is the performance of a denitration catalyst. Among the denitration catalyst systems, the vanadium-tungsten-titanium (V 2O5-WO3/TiO2) catalyst using TiO 2 as a carrier has become the most widely used denitration catalyst in commerce due to the advantages of high activity, good selectivity, strong anti-middle toxicity and the like. TiO 2 is used as a novel functional material, and the catalyst using the novel functional material as a carrier has the advantages of adjustable surface acidity, good low-temperature activity, high-temperature reducibility and the like. However, the conventional vanadium-tungsten-titanium catalyst still has a plurality of technical bottlenecks in practical application, namely, on one hand, anatase type TiO 2 is easy to convert to a rutile crystal form at a high temperature (450 ℃) to cause the catalyst to be sintered and deactivated and the specific surface area to be reduced, and on the other hand, the pore structure of the catalyst directly influences the diffusion efficiency of reaction gas and the loading amount of active components. Therefore, how to increase the specific surface area of the TiO 2 carrier and optimize the pore structure of the TiO 2 carrier becomes a key technical problem for improving the comprehensive performance of the denitration catalyst. China patent publication No. CN115739071B describes that in the preparation of the denitration catalyst, the porosity and specific surface area of the material are increased by using a pore-forming agent, and the scheme adopts conventional organic pore-forming agents such as starch, activated carbon powder, polymethyl methacrylate and the like. However, the prior pore-forming agent still has the following technical defects: The method has the defects that the decomposition temperature range of the conventional single pore-forming agent (such as starch and activated carbon powder) is relatively concentrated, so that gas is easily released in a concentrated manner, and a blank body is cracked or the pore structure is uneven; The method has the defects that the general composite pore-forming agent suitable for vanadium-titanium catalyst carriers is lacked, and the method is particularly suitable for vanadium-titanium denitration catalysts, can improve the specific surface area of the carriers through fractional decomposition and cooperative pore-forming, and has important industrial application value. Disclosure of Invention The invention discloses a composite pore-forming agent of a denitration catalyst and application thereof, and mainly aims to overcome the defects and the shortcomings in the prior art. The technical scheme adopted by the invention is as follows: A composite pore-forming agent of a denitration catalyst comprises finished methyl cellulose and polystyrene. Still further, the mass ratio of the as-built methylcellulose to the polystyrene is from 1:2 to 1:5. A method for preparing a titanium dioxide porous ceramic carrier with high specific surface area by adopting the composite pore-forming agent comprises the following specific steps: Firstly, batching, namely screening titanium dioxide and composite pore-forming agent powder through a 200-mesh screen respectively to obtain a batching for preparation; adding a pore-forming agent, taking the titanium dioxide powder screened in the step one as a base material, and then adding the pore-forming agent powder screened in the step one into the titanium dioxide powder for uniform mixing, wherein the mass ratio of the pore-forming agent powder to the titanium dioxide powder is 1:2-1:5, so as to obtain a mixed ingredient; Step three, kneading and mixing, namely putting the mixed ingredients obtained in the step two into a kneader, adding distilled water, and kneading and mixing for 5 hours to obtain evenly mixed pug; step four, filling a sealed tank for aging, and putting the pug obtained in the step three into the sealed tank for aging for 24 hours; step five, molding the green blank, taking out the aged pug, then putting the pug into a ceramic tube extruder, controlling the extrusion pressure to be 10MPa, and extruding to obtain the green blank; step six, drying the green embryo, namely putting the formed green embryo into an electric heating drying oven for drying, and taking out the dried green embryo after the drying is finished to obtain a dried