A protective coating for preventing coking of refractory castable of waste incinerator

Abstract

This utility model discloses a protective coating for preventing slagging of refractory castable in waste incinerators. It comprises a top layer, a middle layer, a base layer, and a refractory castable layer arranged sequentially from the outside in. The base layer is placed on top of the refractory castable layer, the middle layer is placed on top of the base layer, and the top layer adheres to the middle layer. The top layer, middle layer, base layer, and refractory castable layer form a single integral structure. The top layer is a low-temperature hardening, high-temperature oily silicone coating with strong anti-fouling properties. The middle layer is a high-temperature resistant glaze coating that prevents molten ash from adhering to the glaze layer when it transforms into a semi-molten or solid state during diffusion. The base layer is a high-temperature resistant heat-insulating coating that improves the blackness of the wall surface. Spraying this protective coating onto the inner wall of the waste incinerator prevents ash adhesion, thus preventing slagging in that area, extending the maintenance cycle, reducing the need for maintenance personnel, and thereby lowering maintenance costs.

Description

Technical Field

[0001] This utility model relates to a protective coating for preventing coking of refractory castables in waste incinerators, and belongs to the field of waste incinerators. Background Technology

[0002] With the development and advancement of waste incineration technology in my country, waste-to-energy incineration units have been widely adopted throughout the country. According to incomplete statistics, by the end of 2024, there were more than 2,000 large-scale waste incinerators operating daily in China. During the operation of waste incineration boilers, when the furnace temperature reaches or exceeds the melting point of ash, the solid ash will become molten. At this time, the molten and semi-molten particles in the flue gas solidify when in contact with the lower-temperature heating surface, depositing on the boiler's water-cooled wall tubes to form loose ash deposits. If the particles in the flue gas are still in a molten or semi-molten state when in contact with the wall surface, they will adhere to the heating surface, continuously growing and accumulating to form a dense ash layer, which results in coking, seriously affecting the safe operation of waste incineration boilers. Summary of the Invention

[0003] The technical problem this invention aims to solve is: how to prevent particles from the flue gas from adhering to the inner wall of a waste incineration boiler, thus preventing coking.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is to provide a protective coating for preventing coking of refractory castables in waste incinerators. The coating is characterized by comprising, from the outside in, a top layer, a middle layer, a base layer, and a refractory castable layer, arranged sequentially from the outside in. The base layer is disposed on top of the refractory castable layer, the middle layer is disposed on top of the base layer, and the top layer adheres to the middle layer. The top layer, middle layer, base layer, and refractory castable layer form a single integral structure. The top layer is a low-temperature hardening, high-temperature oily silicone coating with strong anti-fouling ability; the middle layer is a high-temperature resistant glaze coating that makes it difficult for molten ash to adhere to the glaze layer when it transforms into a semi-molten or solid state during diffusion; and the base layer is a high-temperature resistant heat-insulating coating that improves the blackness of the wall surface.

[0005] Preferably, the protective coating is applied to the inner wall of the furnace, and the inner wall of the furnace is sequentially provided with a refractory castable layer, a base coating, a middle coating, and a top coating, with the top coating being the surface layer that contacts the ash and slag inside the furnace.

[0006] Preferably, the specific locations of the refractory castable layer within the furnace of the waste incinerator include, but are not limited to, the front arch, rear arch, furnace top, furnace sidewalls, grate support beams, around the manhole, around the observation hole, burner nozzles, the first channel, and flue bends.

[0007] Preferably, the organosilicon high-temperature oily coating is a hydroxyl silicone oil coating.

[0008] Preferably, the high-temperature resistant glaze coating includes silicon carbide with low surface energy, ceramic powder to improve the smoothness of the coating, and sodium fluorosilicate to promote the densification of the coating.

[0009] Preferably, the high-temperature resistant heat-insulating coating comprises carbon black and silicon carbide to enhance blackness.

[0010] The protective coating of this invention is sprayed onto the inner wall of a waste incineration boiler (e.g., the surface of the water-cooled wall tubes of the waste incineration boiler) to prevent the adhesion of ash and slag, thereby preventing coking in that location, extending the maintenance cycle, reducing the need for maintenance personnel, and thus reducing maintenance costs.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. The surface layer has certain hydrophobicity and anti-coking properties, which makes it difficult for molten ash to coke when it comes into contact with the surface, thereby effectively preventing or reducing the occurrence of coking.

[0013] 2. The intermediate coating further reduces the adhesion of molten ash and significantly improves the overall anti-coking performance of the coating;

[0014] 3. The base coating can improve the blackness of the wall surface, moderately increase the heat absorption, reduce the temperature of the flue gas near the wall, enhance the cooling effect on the molten ash, and further improve the overall anti-coking performance of the coating. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a protective coating used to prevent coking of refractory castables in waste incinerators. Detailed Implementation

[0016] To make this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0017] This invention provides a protective coating for preventing coking of refractory castables in waste incinerators, such as... Figure 1 As shown, it includes a top layer 1, a middle layer 2, a base layer 3, and a refractory castable layer 4 arranged sequentially from the outside to the inside. The base layer 3 is adhered to the top of the refractory castable layer 4, the middle layer 2 is adhered to the top of the base layer 3, and the top layer 1 is adhered to the top of the middle layer 2. The top layer 1, middle layer 2, base layer 3, and refractory castable layer 4 form an integral structure. In this embodiment, each top layer is the outer side; the inner side from the outside to the inside is the direction closer to the inner wall of the furnace, and the outer side is the direction away from the inner wall of the furnace. The protective coating of this utility model is provided on the inner wall of the furnace, that is, the refractory castable layer 4, the base layer 3, the middle layer 2, and the top layer 1 are arranged sequentially on the inner wall of the furnace. Among them, the top layer 1 is the surface layer that contacts the ash and slag in the furnace.

[0018] Topcoat 1 is a high-temperature, oil-based silicone coating. It hardens at low temperatures and has strong anti-fouling properties, allowing the coating to maintain certain hydrophobic and anti-coking properties during the low-temperature phase of the heating process. This prevents molten ash from easily coking into coke upon contact with the surface, effectively preventing or reducing coking. Specifically, the low surface tension of the hydroxyl silicone oil in topcoat 1 enhances its anti-coking properties, and the hydrophobicity of the methyl groups in the hydroxyl silicone oil further reduces coking.

[0019] The intermediate coating 2 is a high-temperature resistant glaze coating. It makes it difficult for molten slag to adhere to the glaze layer when it transforms into a semi-molten or solid state during diffusion, thus reducing the adhesion of the slag and significantly improving the overall anti-coking performance of the coating. Specifically, the intermediate coating 2 contains silicon carbide, ceramic powder, sodium fluorosilicate, etc. Silicon carbide has a low surface energy, which reduces the adhesion of coking particles; ceramic powder improves the smoothness of the coating and reduces the adhesion of coking particles; sodium fluorosilicate promotes coating densification and reduces the deposition of coking particles in pores. Together, they significantly improve the overall anti-coking performance of the coating.

[0020] The base coating 3 is a high-temperature resistant and heat-insulating coating. It can improve the blackness of the wall surface, appropriately increase the heat absorption of the refractory castable layer, reduce the temperature of the flue gas near the furnace wall, and enhance its ability to cool molten ash, that is, enhance the cooling effect on molten ash, which can further improve the overall anti-coking performance of the coating. The base coating 3 contains carbon black and silicon carbide, both of which have a strong effect on enhancing blackness.

[0021] The specific locations of the refractory castable layer 4 in the waste incinerator include, but are not limited to, the front arch, rear arch, furnace top, furnace side wall (above the grate), grate support beam, around the manhole, around the observation hole, burner nozzle, first passage, flue bend, and other locations where the refractory castable layer needs to be cast.

Claims

1. A protective coating for preventing coking of refractory castables in waste incinerators, characterized in that, It includes a top layer (1), a middle layer (2), a base layer (3) and a refractory castable layer (4) arranged sequentially from the outside to the inside. The base layer (3) is set on the refractory castable layer (4), the middle layer (2) is set on the base layer (3), and the top layer (1) is adhered to the middle layer (2). The top layer (1), the middle layer (2), the base layer (3) and the refractory castable layer (4) are an integral structure. The top layer (1) is a low-temperature hardening, high-temperature oily silicone coating with high stain resistance. The middle layer (2) is a high-temperature resistant glaze coating that makes it difficult for molten ash to adhere to the glaze layer when it is transformed into a semi-molten state or solid state during the diffusion process. The base layer (3) is a high-temperature resistant heat insulation coating that improves the blackness of the wall surface.

2. The protective coating for preventing coking of refractory castables in waste incinerators as described in claim 1, characterized in that, The protective coating is provided on the inner wall of the furnace. The inner wall of the furnace is provided with a refractory castable layer (4), a base layer (3), a middle layer (2), and a top layer (1) in sequence. The top layer (1) is the surface layer that contacts the ash and slag in the furnace.

3. A protective coating for preventing coking of refractory castables in waste incinerators as described in claim 2, characterized in that, The specific locations of the refractory castable layer (4) in the furnace of the waste incinerator include, but are not limited to, the front arch, the rear arch, the furnace top, the furnace side wall, the grate support beam, the area around the manhole, the area around the observation hole, the burner nozzle, the first channel, and the flue bend.

4. The protective coating for preventing coking of refractory castables in waste incinerators as described in claim 1, characterized in that, The aforementioned high-temperature oily silicone coating is a hydroxyl silicone oil coating.

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