A high-temperature resistant anti-salting coating for a quenching tower and a preparation method thereof

Abstract

The present invention relates to the field of coating technology, and in particular to a high-temperature, anti-salt-coating coating for quench towers and its preparation method. The high-temperature, anti-salt-coating coating for quench towers comprises the following raw materials in parts by weight: 30-60 parts graphite powder, 5-10 parts tungsten phosphide, 5-10 parts terbium fluoride, 8-15 parts chromium oxide, 3-5 parts antioxidant, 15-20 parts binder, 1-3 parts dispersant, and 3-7 parts deionized water. The high-temperature, anti-salt-coating coating exhibits excellent overall performance, including good hardness, high-temperature resistance, adhesion, salt resistance, and salt spray resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a high-temperature resistant anti-salting coating for a quenching tower and a preparation method thereof. Background Art

[0002] The quench tower is a crucial piece of equipment in hazardous waste incineration systems. Its primary function is to rapidly cool and remove dust from high-temperature flue gases. Passing through the quench tower, the high-temperature flue gas is cooled to 200°C, effectively controlling the re-synthesis of dioxins. It also effectively scrubs and absorbs pollutants such as sulfur dioxide, hydrogen chloride, and small amounts of nitrogen oxides in the acidic gases. However, during quench tower operation, substances such as chlorides, sulfides, and sulfates are inevitably generated, leading to severe salt buildup on the quench tower walls, necessitating shutdowns for salt and ash removal. This not only severely impacts the continuity and stability of the incineration system but also increases operating costs for hazardous waste companies. Effectively addressing the problem of coking on the quench tower walls has become a pressing and practical issue for hazardous waste companies.

[0003] In order to solve the above technical problems, the present invention provides a high-temperature resistant anti-salting coating suitable for the high-temperature environment of a quenching tower, while reducing the formation and accumulation of salt scale on its inner wall. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, one of the objects of the present invention is to provide a high-temperature resistant anti-salt coating for a quenching tower, which has excellent comprehensive performance, good hardness, high temperature resistance, adhesion, salt resistance and salt spray resistance.

[0005] A second object of the present invention is to provide a method for preparing a high-temperature resistant anti-salting coating for a quenching tower, which has simple steps and is easy to operate.

[0006] One of the purposes of the present invention is achieved by the following technical solution:

[0007] A high-temperature resistant and anti-salting coating for a quenching tower comprises the following raw materials in parts by weight: 30-60 parts of graphite powder, 5-10 parts of tungsten phosphide, 5-10 parts of terbium fluoride, 8-15 parts of chromium oxide, 3-5 parts of an antioxidant, 15-20 parts of a binder, 1-3 parts of a dispersant, and 3-7 parts of deionized water.

[0008] Furthermore, the raw materials include the following parts by weight: 45 parts of graphite powder, 8 parts of tungsten phosphide, 6 parts of terbium fluoride, 12 parts of chromium oxide, 4 parts of antioxidant, 19 parts of binder, 2 parts of dispersant, and 5 parts of deionized water.

[0009] Furthermore, the graphite powder consists of graphite powder A and graphite powder B; the mass ratio of the graphite powder A to the graphite powder B is 1:(1-2).

[0010] Furthermore, the average particle size of the graphite powder A is 50 to 80 μm, and the average particle size of the graphite powder B is 5 to 15 μm.

[0011] Furthermore, the antioxidant is silicon powder, the binder is silica sol, and the dispersant is sodium tripolyphosphate.

[0012] Furthermore, the mass concentration of SiO2 in the silica sol is 25-35wt%.

[0013] Furthermore, the particle size of the silicon powder is 1 to 5 μm.

[0014] The second object of the present invention is achieved by adopting the following technical solution:

[0015] The preparation method of the high-temperature resistant anti-salt coating for the quenching tower comprises the following steps:

[0016] (1) weighing the raw materials according to the weight ratio, mixing graphite powder, tungsten phosphide, terbium fluoride, chromium oxide and antioxidant and ball milling to obtain a mixture;

[0017] (2) The mixture of step (1), the binder, the dispersant and the deionized water are mixed and stirred.

[0018] Furthermore, the ball milling time in step (1) is 1 to 3 hours; and the ball-to-material ratio during the ball milling process is (25 to 35):1.

[0019] Furthermore, the stirring speed in step (2) is 800-1000 rpm, and the stirring time is 2-3 h.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention provides a high-temperature resistant anti-salt coating for a quenching tower. The coating formula contains ingredients such as tungsten phosphide, terbium fluoride, and graphite powder, and the graphite powder is composed of two graphite powders with different average particle sizes. The synergistic effect of terbium fluoride and tungsten phosphide in the formula can enhance the salt resistance of the coating. Specifically, tungsten phosphide has a low affinity for sulfur atoms, which can reduce the adhesion and accumulation of sulfides, sulfates, etc. on the surface of the coating, thereby enhancing the salt resistance of the coating; terbium fluoride has a high surface energy and thus has low adhesion. This characteristic can promote the shedding of salt residue on the surface of the coating, thereby enhancing the salt resistance of the coating. In addition, the use of two graphite powders with different average particle sizes in the formula can form a graphite powder system with a reasonable particle size distribution, which not only ensures the stability of the coating and the performance of the coating, but also improves the adhesion of the coating.

[0022] 2. The high-temperature resistant and anti-salt coating of the present invention has excellent comprehensive performance, and has good hardness, high-temperature resistance, adhesion, salt resistance and salt spray resistance.

[0023] 3. The present invention provides a method for preparing a high-temperature resistant anti-salting coating for a quenching tower. The preparation method has simple steps and is easy to practice. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific embodiments. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form new embodiments. Specific conditions not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. All reagents or instruments used, unless otherwise specified, are conventional products obtained through commercial channels.

[0025] In the embodiment of the present invention, the average particle size of graphite powder A is 50-80 μm, the average particle size of graphite powder B is 5-15 μm; and the particle size of silicon powder is 1-5 μm.

[0026] Example

[0027] Example 1

[0028] This embodiment provides a high-temperature, anti-salt coating for a quench tower. The coating comprises, in parts by weight, the following raw materials: 45 parts graphite powder, 8 parts tungsten phosphide, 6 parts terbium fluoride, 12 parts chromium oxide, 4 parts silicon powder, 19 parts silica sol, 2 parts sodium tripolyphosphate, and 5 parts deionized water. The graphite powder comprises graphite powder A and graphite powder B in a 1:1 mass ratio; the silica sol has a SiO2 concentration of 30 wt%.

[0029] This embodiment also provides a preparation method of the high-temperature resistant anti-salting coating for the quenching tower, which is as follows:

[0030] (1) Weighing the raw materials according to the above weight ratio, mixing graphite powder, tungsten phosphide, terbium fluoride, chromium oxide and silicon powder, and ball milling for 2 hours at a ball-to-material ratio of 30:1 to obtain a mixture;

[0031] (2) The mixture of step (1), silica sol, sodium tripolyphosphate and deionized water were mixed and stirred at a speed of 900 rpm for 2.5 h.

[0032] Example 2

[0033] This embodiment provides a high-temperature, anti-salt coating for a quench tower. The coating comprises, in parts by weight, the following raw materials: 60 parts graphite powder, 10 parts tungsten phosphide, 10 parts terbium fluoride, 15 parts chromium oxide, 5 parts silicon powder, 20 parts silica sol, 3 parts sodium tripolyphosphate, and 7 parts deionized water. The graphite powder comprises graphite powder A and graphite powder B in a mass ratio of 1:2; the mass concentration of SiO2 in the silica sol is 35 wt%.

[0034] This embodiment also provides a preparation method of the high-temperature resistant anti-salting coating for the quenching tower, which is as follows:

[0035] (1) Weighing the raw materials according to the above weight ratio, mixing graphite powder, tungsten phosphide, terbium fluoride, chromium oxide and silicon powder, and ball milling for 1 hour at a ball-to-material ratio of 35:1 to obtain a mixture;

[0036] (2) The mixture of step (1), silica sol, sodium tripolyphosphate and deionized water were mixed and stirred at a speed of 1000 rpm for 2 h.

[0037] Example 3

[0038] This embodiment provides a high-temperature, anti-salt coating for a quench tower. The coating comprises, in parts by weight, the following raw materials: 30 parts graphite powder, 5 parts tungsten phosphide, 5 parts terbium fluoride, 8 parts chromium oxide, 3 parts silicon powder, 15 parts silica sol, 1 part sodium tripolyphosphate, and 3 parts deionized water. The graphite powder comprises graphite powder A and graphite powder B in a 1:1 mass ratio; the silica sol has a SiO2 concentration of 25 wt%.

[0039] This embodiment also provides a preparation method of the high-temperature resistant anti-salting coating for the quenching tower, which is as follows:

[0040] (1) Weighing the raw materials according to the above weight ratio, mixing graphite powder, tungsten phosphide, terbium fluoride, chromium oxide and silicon powder, and ball milling for 3 hours at a ball-to-material ratio of 25:1 to obtain a mixture;

[0041] (2) The mixture of step (1), silica sol, sodium tripolyphosphate and deionized water were mixed and stirred at a speed of 800 rpm for 3 h.

[0042] Comparative Example

[0043] Comparative Example 1

[0044] This comparative example provides a coating composed, in parts by weight, of the following raw materials: 45 parts graphite powder, 8 parts tungsten oxide, 6 parts terbium fluoride, 12 parts chromium oxide, 4 parts silicon powder, 19 parts silica sol, 2 parts sodium tripolyphosphate, and 5 parts deionized water. The graphite powder is composed of graphite powder A and graphite powder B in a 1:1 mass ratio; the mass concentration of SiO2 in the silica sol is 30 wt%.

[0045] The specific preparation method of the coating of this comparative example is the same as that of Example 1.

[0046] Comparative Example 2

[0047] This comparative example provides a coating comprising, in parts by weight, the following raw materials: 45 parts graphite powder, 8 parts tungsten phosphide, 6 parts terbium oxide, 12 parts chromium oxide, 4 parts silicon powder, 19 parts silica sol, 2 parts sodium tripolyphosphate, and 5 parts deionized water. The graphite powder comprises graphite powder A and graphite powder B in a 1:1 mass ratio; the mass concentration of SiO2 in the silica sol is 30 wt%.

[0048] The specific preparation method of the coating of this comparative example is the same as that of Example 1.

[0049] Comparative Example 3

[0050] This comparative example provides a coating composed, in parts by weight, of the following raw materials: 45 parts graphite powder, 14 parts terbium fluoride, 12 parts chromium oxide, 4 parts silicon powder, 19 parts silica sol, 2 parts sodium tripolyphosphate, and 5 parts deionized water. The graphite powder is composed of graphite powder A and graphite powder B in a 1:1 mass ratio; the mass concentration of SiO2 in the silica sol is 30 wt%.

[0051] The specific preparation method of the coating of this comparative example is the same as that of Example 1.

[0052] Comparative Example 4

[0053] This comparative example provides a coating composed, in parts by weight, of the following raw materials: 45 parts graphite powder, 14 parts tungsten phosphide, 12 parts chromium oxide, 4 parts silicon powder, 19 parts silica sol, 2 parts sodium tripolyphosphate, and 5 parts deionized water. The graphite powder is composed of graphite powder A and graphite powder B in a 1:1 mass ratio; the mass concentration of SiO2 in the silica sol is 30 wt%.

[0054] The specific preparation method of the coating of this comparative example is the same as that of Example 1.

[0055] Comparative Example 5

[0056] This comparative example provides a coating composed of the following raw materials, in parts by weight: 45 parts graphite powder B, 8 parts tungsten phosphide, 6 parts terbium fluoride, 12 parts chromium oxide, 4 parts silicon powder, 19 parts silica sol, 2 parts sodium tripolyphosphate, and 5 parts deionized water. The silica sol has a mass concentration of 30 wt%.

[0057] The specific preparation method of the coating of this comparative example is the same as that of Example 1.

[0058] Test example

[0059] The properties of the coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were investigated, and the specific indicators and detection methods were as follows:

[0060] ① Pencil hardness: The pencil hardness of the coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was tested in accordance with GB / T 6739-2006. The results are shown in Table 1.

[0061] ② Adhesion: The adhesion of the coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was tested in accordance with GB / T 1720-2020. The results are shown in Table 1.

[0062] ③ Impact strength: The impact strength of the coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was tested in accordance with GB / T 1732-2020. The results are shown in Table 1.

[0063] ④ High temperature resistance: The high temperature resistance of the coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was tested in accordance with GB / T 1735-2009. The temperature was increased at a heating rate of 5°C / min, and the temperature at which cracking and shedding occurred was tested. The results are shown in Table 1.

[0064] ⑤ Salt spray resistance: The salt spray resistance of the coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was tested in accordance with GB / T 1771-2007. The results are shown in Table 1.

[0065] ⑥ Salt resistance: According to the conventional method, the coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were used to prepare coatings on the heated surface of a quenching tower. The coating thickness was 150 μm. The salt formation of the coatings was tested after one month of service in the quenching tower. The results are shown in Table 1.

[0066] Table 1

[0067]

[0068]

[0069] As can be seen from Table 1, the coatings prepared in Examples 1 to 3 of the present invention have high hardness, good adsorption capacity, high impact strength, and excellent salt spray resistance and salt accumulation resistance under high temperature service of 1900-2000°C.

[0070] Compared with Examples 1 to 3, the salt resistance of the coatings obtained in Comparative Examples 1 to 4 is significantly reduced. Analysis shows that Comparative Example 1 uses tungsten oxide instead of tungsten phosphide; Comparative Example 2 uses terbium oxide instead of terbium fluoride; Comparative Example 3 omits tungsten phosphide and increases the amount of terbium fluoride; Comparative Example 4 omits terbium fluoride and increases the amount of tungsten phosphide, and the salt resistance of the coating obtained is significantly reduced. The above results show that the synergistic effect of terbium fluoride and tungsten phosphide can enhance the salt resistance of the coating. Further analysis shows that tungsten phosphide has a low affinity for sulfur atoms, which can reduce the adhesion and accumulation of sulfides, sulfates, etc. on the surface of the coating, thereby enhancing the salt resistance of the coating; terbium fluoride has a high surface energy and therefore has low adhesion. This characteristic can promote the shedding of salt residue on the surface of the coating, thereby enhancing the salt resistance of the coating.

[0071] Compared with Examples 1 to 3, the adhesion of the coating obtained in Comparative Example 5 is reduced. Analysis shows that Comparative Example 5 only uses graphite powder B with an average particle size of 5 to 15 μm. The above results show that the combination of two graphite powders with different average particle sizes can form a graphite powder system with a reasonable particle size distribution, which not only ensures the stability of the coating and the performance of the coating, but also improves the adhesion of the coating. In summary, the high-temperature resistant and anti-salting coating of the present invention has excellent comprehensive performance, and has good hardness, high temperature resistance, adhesion, salt resistance, and salt spray resistance.

[0072] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A high temperature resistant anti-salting coating for a quenching tower, characterized in that: The method comprises the following raw materials in parts by weight: 30-60 parts of graphite powder, 5-10 parts of tungsten phosphide, 5-10 parts of terbium fluoride, 8-15 parts of chromium oxide, 3-5 parts of antioxidant, 15-20 parts of binder, 1-3 parts of dispersant, and 3-7 parts of deionized water; The graphite powder consists of graphite powder A and graphite powder B; the mass ratio of the graphite powder A to the graphite powder B is 1:(1-2); the average particle size of the graphite powder A is 50-80 μm, and the average particle size of the graphite powder B is 5-15 μm.

2. The high temperature resistant anti-salt coating for a quenching tower according to claim 1, characterized in that The method comprises the following raw materials in parts by weight: 45 parts of graphite powder, 8 parts of tungsten phosphide, 6 parts of terbium fluoride, 12 parts of chromium oxide, 4 parts of antioxidant, 19 parts of binder, 2 parts of dispersant and 5 parts of deionized water.

3. The high temperature resistant anti-salt coating for a quenching tower according to claim 2, characterized in that The antioxidant is silicon powder, the binder is silica sol, and the dispersant is sodium tripolyphosphate.

4. The high temperature resistant anti-salt coating for a quenching tower according to claim 3, characterized in that The mass concentration of SiO2 in the silica sol is 25-35wt%.

5. The method for preparing the high-temperature resistant anti-salting coating for a quenching tower according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) weighing the raw materials according to the weight ratio, mixing graphite powder, tungsten phosphide, terbium fluoride, chromium oxide and antioxidant and ball milling to obtain a mixture; (2) The mixture of step (1), the binder, the dispersant and the deionized water are mixed and stirred.

6. The method for preparing the high-temperature resistant anti-salt coating for a quenching tower according to claim 5, wherein: The ball milling time in step (1) is 1 to 3 hours; the ball-to-material ratio during the ball milling process is (25 to 35):

1.

7. The method for preparing the high-temperature resistant anti-salt coating for a quenching tower according to claim 5, wherein: The stirring speed in step (2) is 800-1000 rpm, and the stirring time is 2-3 h.

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