CN113969071B

CN113969071B - High-temperature anti-sticking coating capable of catalytically decomposing dioxin

Info

Publication number: CN113969071B
Application number: CN202011142780.5A
Authority: CN
Inventors: 戴雷
Original assignee: Shenzhen Youyi Material Technology Co ltd
Current assignee: Shenzhen Youyi Material Technology Co ltd
Priority date: 2020-10-23
Filing date: 2020-10-23
Publication date: 2022-11-04
Anticipated expiration: 2040-10-23
Also published as: CN113969071A

Abstract

The invention relates to a high-temperature anti-sticking coating capable of catalytically decomposing dioxin, which comprises the following components: 35-70wt% ceramic filler, 15-55wt% binder, 0.5-5wt% yb/Tm co-doped fluoride nanocrystals; in the Yb/Tm co-doped fluoride nano-crystal, the Tm doping amount is 0.1-2mol% and the Yb doping amount is 0.5-5mol% based on 100mol% of fluoride; the average grain diameter of the nano-crystal is 20-100nm, and the nano-crystal can absorb visible light or infrared light and convert the visible light or infrared light into ultraviolet light. The characteristic that Yb/Tm codoped fluoride nanocrystalline absorbs visible light/infrared light to generate up-conversion luminescence is utilized to realize purple light luminescence, so that the photolysis reaction of dioxin is caused, and visible light and infrared radiation generated by incineration of an incinerator are recovered to a certain extent. The fluoride is selected from calcium fluoride, barium fluoride and strontium fluoride, is not only a good luminescent material substrate, but also a good lubricating material, and has a remarkable effect on the anti-bonding performance of the coating.

Description

High-temperature anti-sticking coating capable of catalytically decomposing dioxin

Technical Field

The invention belongs to the field of coatings, and particularly relates to a high-temperature coating which can resist high temperature and prevent bonding and can catalytically decompose dioxin in a high-temperature environment.

Background

Along with the development of economy in China, urban population is rapidly increased, and domestic garbage is continuously increased. Current waste disposal means include landfills and incineration. The landfill inevitably causes secondary pollution, and the garbage is treated by burning in an effective method at present. The problem of corrosion of a boiler in a high-temperature environment is inevitably faced in the waste incineration process, and meanwhile, due to the complex components of the waste, new pollutants are generated in the incineration process, and dioxin is the most concerned pollutant at present.

For the protection of pipelines, boilers and the like in a high-temperature environment, coating a protective coating is an effective method, and if the coating has stronger performances of corrosion resistance and the like at a high temperature, the coating is very important for avoiding the damage of the boiler pipelines and protecting the environment.

At present, research and application coatings can have certain effects, such as certain wear resistance, high-temperature oxidation resistance and the like, but under the application scenes of similar waste incineration, power plants and the like, due to the complex diversity of application environments, the performance of the coatings is reduced under the long-time use, and the coatings fall off due to the local performance reduction, so that the safe operation of the whole equipment is influenced. Therefore, it is critical to develop a coating with durable and excellent properties in high temperature environment.

Dioxin is a typical organic pollutant, brings great threat to an ecological system and human health, is very important to control the emission of the dioxin in the face of increasing garbage treatment amount, and is more strict when the emission standard of the dioxin is more recent, so that the reduction of the emission of the dioxin is also the key point of controlling the pollutants generated by the current garbage incineration.

At present, the whole process control, including three means of source reduction enhancement, process control optimization and terminal treatment improvement, must be implemented on key dioxin pollution sources such as waste incineration and the like.

The source reduction refers to the use of management means and technical means to reduce the content of dioxin precursors in production raw materials and reduce the potential risk of generating dioxin, and mainly controls polychlorinated biphenyl and wastes with high content of organic chlorine (PVC) (such as medical wastes and agricultural mulching films) to enter an incinerator.

The process control means that the process operation parameters are controlled in the production process, the generation condition of dioxin is avoided, the generation of the dioxin is reduced, a technology of '3T + E' is generally adopted, namely the incineration temperature is higher than 850 ℃, the retention time is 2.0 s, the full gas-solid turbulence degree is kept, and the excessive air amount enables the concentration of O2 in the flue gas to be 6-11%. And a quenching system is arranged to carry out quenching treatment on the high-temperature flue gas generated by incineration, the retention time of the flue gas in the temperature range of 200-500 ℃ is controlled to be less than 1s, the deposition of the fly ash on the inner surface of equipment is reduced, so that a catalyst carrier required by the generation of dioxin is reduced, and the risk of resynthesis of the dioxin is reduced. The continuous time of stable operation of the incineration system is improved as much as possible, the times of starting and stopping the incinerator are reduced, and dioxin generated due to abnormal working conditions is reduced.

The tail end treatment means that a targeted treatment technology is adopted on the basis of a flue gas pollution control measure to control the emission of dioxin to the environment. Activated carbon injection and bag-type dust remover are effective ways for removing dioxin substances in flue gas, and the large domestic waste incineration flue gas purification system in China basically adopts a flue gas combined treatment process of 'deacidification by a semi-dry method, adsorption of dioxin by activated carbon injection and dust removal by the bag-type dust remover'. If a flue gas selective catalytic denitration device is adopted in the flue gas purification system, the emission of NOx is controlled, and simultaneously the emission amount of dioxin in flue gas is further degraded.

At present, the incineration temperature in the garbage incinerator is basically set to be above 850 ℃ so as to realize the effective decomposition of dioxin, a large amount of visible light and infrared light can be simultaneously generated in the incinerator at the temperature, and the energy of the visible light and the infrared light is not fully utilized.

Disclosure of Invention

Dioxins can absorb ultraviolet light or receive energy from excited molecules to put the molecules in an excited state, thereby causing photolytic reactions. However, ultraviolet radiation is not generally generated in a waste incinerator. If ultraviolet light is introduced through equipment such as an ultraviolet lamp tube, under severe conditions in the incinerator, firstly, the ultraviolet lamp tube cannot resist high temperature, and secondly, smoke dust and ash generated by combustion can be quickly bonded on the outer surface of the ultraviolet lamp tube, so that the ultraviolet light transmittance in the lamp tube is greatly reduced. Therefore, it is highly desirable to provide other ways of introducing ultraviolet light, which has both good high temperature resistance and anti-adhesion property, and also has the effect of decomposing dioxin, which is a core improvement of the present invention.

Aiming at the problems of a coating in a high-temperature environment of a garbage incinerator in the prior art and the requirement of dioxin control, the invention provides the coating with good high-temperature resistance and anti-sticking performance in the high-temperature environment, the coating has a good effect on decomposing dioxin, and visible light and infrared light generated by the incineration of garbage in the incinerator can be fully utilized to decompose the dioxin. In order to achieve the purpose, the ultraviolet luminescent nanocrystalline is further introduced into the high-temperature protective coating, can absorb a large amount of visible light and infrared light generated by high-temperature combustion in a furnace to generate an up-conversion effect, and converts the visible light and the infrared light into ultraviolet light, so that the decomposition of dioxin is promoted.

The technical scheme of the invention is as follows.

A high-temperature anti-sticking coating capable of catalytically decomposing dioxin comprises the following components: 35-70wt% filler, 15-55wt% binder, 0.5-5wt% yb/Tm co-doped fluoride nanocrystal; in the Yb/Tm co-doped fluoride nano-crystal, the Tm doping amount is 0.1-2mol% and the Yb doping amount is 0.5-5mol% based on 100mol% of fluoride; the average grain diameter of the nano-crystal is 20-100nm, and the nano-crystal can absorb visible light or infrared light and convert the visible light or infrared light into ultraviolet light.

Research shows that Yb < 3+ > as a sensitizer is co-doped with Tm < 3+ > and can absorb visible light and infrared light (800 nm and 980 nm) with longer wavelengths and generate upconversion luminescence of visible light (480 nm and 650 nm) and ultraviolet light (300 nm and 360 nm) with shorter wavelengths. The invention utilizes the characteristic of the Yb/Tm codoped fluoride nano-crystal to realize purple light luminescence so as to cause the photolysis reaction of dioxin. The preparation method of the doped fluoride nanocrystal is the prior art, such as a hydrothermal method, a sol-gel method and the like, and is not described herein again.

Further, said high temperature release coating also comprises 0.5-5wt% Er-doped fluoride nanocrystals. In the Er < 3+ > doped fluoride nanocrystalline, the doping amount of Er is 0.2-2mol% based on 100mol% of fluoride; the average grain diameter of the nano-crystal is 20-100nm. As the up-conversion luminescence spectrum of the Yb/Tm co-doped fluoride has more undesirable visible light (480 nm) besides ultraviolet light, and the Er-doped fluoride nanocrystalline can exactly absorb the visible light near 480nm to generate up-conversion ultraviolet luminescence (310 nm, 340nm and 380 nm), the ultraviolet luminescence efficiency of the coating is improved.

Further, the fluoride is at least one of calcium fluoride, barium fluoride and strontium fluoride. The calcium fluoride, the barium fluoride and the strontium fluoride are not only good luminescent material substrates, but also good lubricating materials, and have remarkable effect on the anti-bonding performance of the coating.

Further, the filler comprises 32-60% of alumina, 1-5% of zirconium silicate and 2-10% of zirconium oxide in percentage by mass of the coating; 0.5-2% of mica powder; 1-5% carbon nanotubes; 0.5-2% graphene; 0.1-2% yttria; 0.1-2% cerium oxide; 1-5% palladium oxide; 1-8% V ₂ O ₅ ；1-5%TiO ₂ 。TiO ₂ Is a photocatalyst known to decompose dioxins, however, tiO ₂ The forbidden band width is large (3.2 eV), and the catalytic performance of the catalyst can be maximized under the ultraviolet light. The improvement of the application is that the ultraviolet luminescent material is introduced into the coating, which is beneficial to further improving TiO ₂ Efficiency of photocatalytic decomposition of dioxins.

The high-temperature anti-adhesion coating capable of catalytically decomposing dioxin according to claim 1, characterized in that the particle size of zirconium silicate is 30 to 80nm and the particle size of zirconium oxide is 10 to 30 μm. Preferably, the particle size of zirconium silicate may be 40-60nm, the particle size of zirconium oxide may be 15-20 μm, and the like. The selection of zirconium silicate and zirconium oxide in the above particle size range in the ceramic aggregate is critical to enhance crack resistance and strength. The zirconium silicate and zirconium oxide in the particle size range and other components such as mica powder and the like obviously influence the performance of the coating, and the dosage of the materials is important.

Further, the TiO is ₂ The dosage is 1-3%. In the prior art, tiO ₂ Generally, the amount of the compound is larger than that of the compound V ₂ O ₅ The compatibility of the components achieves certain effect, and in the invention, research finds that TiO is added into the coating layer ₂ The dosage of the catalyst is far less than that in the prior art, and a better catalytic degradation effect can still be achieved.

Further, the coating also comprises 15-55% of a binder and the balance of water.

Further, the binder is one or more of aluminum dihydrogen phosphate, aluminum phosphate or silica sol.

The invention also provides a preparation method of the high-temperature anti-sticking coating capable of catalytically decomposing dioxin, which comprises the following steps:

(1) Mixing and stirring the ceramic filler and the binder uniformly to obtain a mixture; (2) Adding fluoride nanocrystalline into the mixture, and uniformly mixing to obtain the coating; the coating is formed by processing the surface of the target part in a spraying mode.

The beneficial effects of the invention include:

(1) The invention has the first improvement point that purple light luminescence is realized by utilizing the characteristic that Yb/Tm codoped fluoride nanocrystalline absorbs visible light/infrared light to generate up-conversion luminescence, so that the photolysis reaction of dioxin is caused, and visible light and infrared radiation generated by incineration of an incinerator are recovered to a certain extent. The fluoride is selected from calcium fluoride, barium fluoride and strontium fluoride, is not only a good luminescent material substrate, but also a good lubricating material, and has a remarkable effect on the anti-bonding performance of the coating.

(2) The second improvement point of the invention is that the upconversion luminescent spectrum of the Yb/Tm codoped fluoride has more undesirable visible light (480 nm) besides ultraviolet light, and the Er-doped fluoride nanocrystalline is further added to absorb the visible light near 480nm to generate upconversion ultraviolet luminescence (310 nm, 340nm and 380 nm), so that the ultraviolet luminescent efficiency of the coating is improved.

(3) The third improvement point of the invention is that the ultraviolet light generated by the ultraviolet luminescent nanocrystalline can further improve TiO ₂ Efficiency of photocatalytic decomposition of dioxins.

(4) Although the direct photolysis of dioxin by ultraviolet light is considered to be low in efficiency or incomplete in photolysis, the scheme of the invention surprisingly discovers that the method is favorable for enabling dioxin to be in an activated state due to the combination of ultraviolet light photolysis, photocatalytic decomposition and a high-temperature decomposition means in the furnace, the decomposition efficiency is greatly improved, the working temperature in the furnace can be reduced by 50-100 ℃ from the existing temperature of more than 850 ℃, the energy consumption is favorably reduced, and the service life of equipment is prolonged.

In addition, the coating has good compatibility through reasonable matching of raw materials, shows good strength, hardness, corrosion resistance and other properties in a high-temperature complex environment, can not fall off or crack after long-time use, and effectively protects a boiler or a pipeline from being corroded; the invention can achieve better effect of catalyzing and decomposing dioxin through the selection of components. And the coating can enable heat transfer of a boiler and a pipeline to be more uniform, and the performance of the coating is improved, and simultaneously dioxin can be further catalytically degraded.

Detailed Description

The coating according to the invention is further illustrated by the following embodiments. In particular, the coating disclosed by the invention is suitable for high-temperature and complex environments such as power plants, waste incineration plants and the like.

Example 1

A high-temperature anti-sticking coating capable of catalytically decomposing dioxin comprises the following components: 55wt% ceramic filler, 35wt% binder, 1.2wt% yb/Tm co-doped fluoride nanocrystals, balance water; in the Yb/Tm co-doped fluoride nano crystal, the Tm doping amount is 0.5mol% and the Yb doping amount is 2mol% based on 100mol% of fluoride; the average grain diameter of the nano-crystal is 70nm.

Wherein the filler comprises the following components: 50% of alumina, 2% of zirconium silicate and 3% of zirconium oxide; 1% of mica powder; 2% carbon nanotubes; 0.8% graphene; 0.3% yttria; 0.4% cerium oxide; 2% palladium oxide; 2% V ₂ O ₅ ；1%TiO ₂ Wherein the particle size of the zirconium silicate is 45nm, and the particle size of the zirconium oxide is 20 microns.

The preparation method of the coating comprises the following steps:

(1) Mixing and stirring the ceramic filler, the binder and water uniformly to obtain a mixture; (2) Adding fluoride nanocrystalline into the mixture, and uniformly mixing to obtain the coating; the coating is sprayed on the surface of the target part to form a coating.

Example 2

Compared to example 1, 1wt% er-doped fluoride nanocrystals were also added. In the Er-doped fluoride nanocrystalline, the doping amount of Er is 0.3mol% based on 100mol% of fluoride; the average grain diameter of the nano-crystal is 55nm. The rest is the same as in example 1.

Comparative example 1

The same as example 1 was repeated except that no fluoride nanocrystal was added as compared with example 1.

Comparative example 2

Replacing 1.2wt% yb/Tm co-doped fluoride nanocrystals with 1.2wt% yb/Tm co-doped yttria nanoparticles as compared to example 1 without adding any fluoride nanocrystals; in the Yb/Tm co-doped yttrium oxide nano-particles, the doping amount of Tm is 0.5mol% and the doping amount of Yb is 2mol% based on 100mol% of yttrium oxide; the average particle size of the nanoparticles is 70nm. The rest is the same as in example 1.

The rest is the same as in example 1.

The effect on the catalytic degradation of dioxins was determined with the examples and comparative examples, the test method being carried out with reference to the general methods of the prior art: and (3) introducing the dioxin into a sealed furnace with preset high temperature for testing, covering the furnace wall by a sample with a coating, and detecting the content of the dioxin in the exhaust port every 1s, wherein the test result is as follows.

The bonding test is carried out in a real garbage incinerator, different samples with coatings are arranged in the same position in a hearth, and the bonding condition of the surfaces of the coatings is checked after the furnace is operated for one week.

According to the embodiment and the comparative example, the catalyst has good effect of catalyzing and degrading the dioxin, can quickly decompose the dioxin even if the furnace temperature is reduced by 50-100 ℃ due to high decomposition efficiency, and is not easy to adhere in a long-time running state.

The above examples are merely illustrative for clearly illustrating the present invention and are not intended to limit the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any obvious variations or modifications which come within the spirit and scope of the invention are desired to be protected by the following claims.

Claims

1. The high-temperature anti-sticking coating capable of catalytically decomposing dioxin is characterized by comprising the following components: 35-70wt% filler, 15-55wt% binder, 0.5-5wt% yb/Tm co-doped fluoride nanocrystals, and the balance water; in the Yb/Tm co-doped fluoride nano-crystal, the Tm doping amount is 0.1-2mol% and the Yb doping amount is 0.5-5mol% based on 100mol% of fluoride; the average grain size of the nano-crystal is 20-100nm, and the nano-crystal can absorb visible light or infrared light and convert the visible light or infrared light into ultraviolet light;

said high temperature anti-sticking coating further comprising 0.5-5wt% of Er-doped fluoride nanocrystals, wherein the Er-doped fluoride nanocrystals have an Er doping amount of 0.2-2mol% based on 100mol% of fluoride; the average grain diameter of the nano-crystal is 20-100nm;

the filler comprises 32-60% of alumina, 1-5% of zirconium silicate and 2-10% of zirconium oxide in percentage by mass of the coating; 0.5-2% of mica powder; 1-5% carbon nanotubes; 0.5-2% graphene; 0.1-2% yttria; 0.1-2% cerium oxide; 1-5% palladium oxide; 1-8% of V ₂ O ₅ ；1-5%TiO ₂ ；

The particle size of the zirconium silicate is 30-80nm, and the particle size of the zirconium oxide is 10-30 mu m.

2. The high-temperature anti-adhesion coating capable of catalyzing decomposition of dioxin according to claim 1, wherein the fluoride is at least one of calcium fluoride, barium fluoride and strontium fluoride.

3. The high-temperature anti-adhesion coating capable of catalyzing decomposition of dioxin according to claim 1, characterized in that the binder is one or more of aluminum dihydrogen phosphate, aluminum phosphate and silica sol.

4. The method of claim 1 for preparing a high temperature release coating from a high temperature release coating which can catalyze the decomposition of dioxin, comprising the steps of:

(1) Mixing and stirring the filler and the binder uniformly to obtain a mixture;

(2) Adding fluoride nano-crystals into the mixture, and uniformly mixing to obtain a coating; the coating is formed by processing the surface of the target part in a spraying mode.