Comprehensive treatment method for preventing coking in garbage incinerator

Abstract

The invention provides a comprehensive treatment method for preventing coking in a garbage incinerator. The comprehensive treatment method comprises the steps that fireproof hanging bricks are arranged on the side wall in the incinerator of a water-cooling furnace wall; or holes are formed in the side wall in the incinerator of the air cooling furnace wall, and smoke flows back. Coking is prevented by means of flue gas backflow on the air-cooled furnace wall or brick hanging on the water-cooled furnace wall, meanwhile, the anti-coking coatings are sprayed to the front arch and the rear arch of the throat, the service life of refractory materials in the incinerator is prolonged, the anti-coking corrosion resistance of the refractory materials in the incinerator is improved, and long-period stable operation of the boiler is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of incinerator coking, and particularly relates to a comprehensive treatment method for preventing coking in a waste incinerator. BACKGROUND

[0002] The garbage in China has the characteristics of high moisture, high kitchen waste and high chlorine, and the coking rate is relatively high. With the promotion of the policy of collaborative disposal of industrial solid waste through garbage classification, the calorific value of the garbage entering the garbage incinerator in different urban areas is different. The combustion of high-calorific-value garbage causes the problem of overheating in the furnace, which easily causes the coking of the incinerator and brings challenges to the clean and stable operation of the garbage incinerator. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a comprehensive treatment method for preventing coking in a waste incinerator, which can reduce the coking in the incinerator.

[0004] The present application provides a comprehensive treatment method for preventing coking in a waste incinerator, which comprises arranging refractory hanging bricks in the side wall of the incinerator of a water-cooled furnace wall; or opening holes for flue gas backflow in the side wall of the incinerator of an air-cooled furnace wall.

[0005] A coking-resistant coating is sprayed on the arches before and after the throat of the incinerator.

[0006] Preferably, the composition of the refractory hanging bricks comprises silicon carbide, silicon nitride, silicon dioxide, rare earth oxide and aluminum oxide.

[0007] Preferably, the composition of the refractory hanging bricks comprises silicon carbide 75wt%, silicon nitride 14wt%, silicon dioxide 3wt%, rare earth oxide 2wt% and the balance of aluminum oxide.

[0008] Preferably, the coking-resistant coating comprises silicon carbide, zirconium oxide, yttrium oxide, chromium oxide and aluminum oxide.

[0009] Preferably, the thickness of the coking-resistant coating is 1-2mm.

[0010] Preferably, the coking-resistant coating comprises silicon carbide, zirconium oxide, yttrium oxide, chromium oxide and aluminum oxide.

[0011] Preferably, the coking-resistant coating comprises silicon carbide 48wt%, zirconium oxide 15wt%, yttrium oxide 7wt%, chromium oxide 25wt% and the balance of aluminum oxide.

[0012] Preferably, a refractory material pouring layer is arranged on the radiant heating surface of the incinerator; and the thickness of the refractory material pouring layer is 30-50mm.

[0013] Preferably, the refractory material pouring layer comprises silicon carbide, silicon oxide, aluminum oxide and yttrium oxide.

[0014] Preferably, the refractory material casting layer comprises 50wt% silicon carbide, 30wt% silicon oxide, 12wt% aluminum oxide and 8% yttrium oxide.

[0015] Preferably, the thickness of the refractory hanging brick is 40-80mm.

[0016] The present application provides a comprehensive anti-coking method for a waste incinerator, comprising: arranging a refractory hanging brick on the side wall of the incinerator with a water-cooled furnace wall; or opening a hole for flue gas backflow on the side wall of the incinerator with an air-cooled furnace wall. The present application prevents coking by using flue gas backflow for the air-cooled furnace wall or hanging bricks for the water-cooled furnace wall, and simultaneously spraying an anti-coking coating on the front and rear arches of the throat to improve the service life and anti-coking and corrosion resistance of the refractory material in the incinerator, thereby ensuring long-term stable operation of the boiler. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Figure 1 is a schematic diagram of part of the structure of the waste incinerator in the present application;

[0018] Figure 2 Figure 2 is a schematic diagram of the anti-coking treatment method of Example 1 of the present application;

[0019] Figure 3 Figure 3 is a schematic diagram of the anti-coking treatment method of Example 2 of the present application. DETAILED DESCRIPTION

[0020] The present application provides a comprehensive anti-coking method for a waste incinerator, comprising arranging a refractory hanging brick on the side wall of the incinerator with a water-cooled furnace wall; or opening a hole for flue gas backflow on the side wall of the incinerator with an air-cooled furnace wall.

[0021] Spraying an anti-coking coating on the front and rear arches of the throat of the incinerator.

[0022] The prior art is prone to coking in the high-temperature area of the left and right side walls and the front and rear arches of the throat of the combustion section of the incinerator. The present application prevents coking by using flue gas backflow for the air-cooled furnace wall or hanging bricks for the water-cooled furnace wall, and simultaneously spraying an anti-coking coating on the front and rear arches of the throat to improve the service life and anti-coking and corrosion resistance of the refractory material in the incinerator, thereby ensuring long-term stable operation of the boiler.

[0023] The incinerator in the present application is a device for incinerating waste, which is composed of a grate and a hearth. The water-cooled wall in the incinerator refers to a vertical boiler heating surface laid on the inner wall of the furnace wall, which is mainly used to absorb the radiation heat emitted by the flame and high-temperature flue gas in the furnace. It is the main type of boiler evaporation heating surface and is a basic component in the boiler water circulation loop, which has the functions of cooling and protecting the furnace wall.

[0024] This invention targets waste incinerators with air-cooled furnace walls on the left and right sides. The left and right sides use a flue gas recirculation method to prevent coking, combined with anti-coking coatings sprayed on the front and rear arches of the throat. Flue gas recirculation refers to a combustion method in which part of the flue gas generated during combustion is mixed with the oxidant and then participates in the combustion process again. A fan is used to extract the tail flue gas and reinject it into the furnace, which is a low-NOx combustion technology.

[0025] The waste incinerator in this invention is a commercially available boiler manufactured by Nantong Wanda Boiler Factory. Figure 1 This is a schematic diagram of the internal structure of the waste incinerator in this invention, wherein 1 is the front arch, 2 is the rear arch, 3 is the incinerator throat, 4 is the lower part of the first flue, 5 is the upper part of the first flue, 6 is the upper part of the second flue, 7 is the lower part of the second flue, and 8 is the third flue.

[0026] In the waste incinerator of the present invention, the first flue, the second flue and the third flue are arranged in parallel. The walls of them are the radiant heating surfaces of the incinerator, such as the front arch, the rear arch and the throat of the incinerator, and are basically covered with a refractory material casting layer.

[0027] The refractory bricks described in this invention comprise silicon carbide, silicon nitride, silicon dioxide, rare earth oxides, and alumina. In a specific embodiment, the refractory bricks comprise 75 wt% silicon carbide, 14 wt% silicon nitride, 3 wt% silicon dioxide, 2 wt% yttrium oxide, and the balance alumina. The thickness of the refractory bricks described in this invention is 40-80 mm; in a specific embodiment, the thickness is 50 mm.

[0028] This invention involves spraying an anti-coking coating onto the front and rear arches of the throat of an incinerator; the thickness of the anti-coking coating is 1-2 mm; in a specific embodiment, the thickness is 1 mm. The anti-coking coating comprises silicon carbide, zirconium oxide, yttrium oxide, chromium oxide, and aluminum oxide. In a specific embodiment, the anti-coking coating comprises 48% silicon carbide, 15% zirconium oxide, 7% yttrium oxide, 25% chromium oxide, with the balance being aluminum oxide.

[0029] Preferably, a refractory material casting layer is provided on the radiant heating surface of the incinerator in this invention; the aforementioned anti-coking coating and refractory bricks are both provided on the refractory material casting layer. The thickness of the refractory material casting layer is 30-50 mm. The refractory material casting layer comprises silicon carbide, silicon oxide, alumina, and yttrium oxide; in a specific embodiment, the refractory material casting layer contains 50 wt% silicon carbide, 30 wt% silicon oxide, 12 wt% alumina, and 8% yttrium oxide.

[0030] Currently, there are few methods for preventing coking in incinerators, and their effectiveness is not good. This invention proposes to prevent coking by using flue gas recirculation in the high-temperature zone of the incinerator in air-cooled furnace walls, and to prevent coking by using brick hanging in water-cooled furnace walls. At the same time, anti-coking coatings are sprayed on the front and rear arches of the throat, providing a complete and comprehensive treatment method for the incinerator.

[0031] To further illustrate the present invention, the following detailed description of a comprehensive method for preventing coking inside a waste incinerator provided by the present invention is provided in conjunction with embodiments, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0032] Example 1

[0033] Figure 2 This is a schematic diagram of the anti-coking treatment method in Embodiment 1 of the present invention;

[0034] A refractory casting layer is arranged on the surface of the front and rear arches (red area), and an anti-coking ceramic coating is arranged on the surface of the refractory casting layer; bricks are arranged on the left and right side walls (green area) inside the incinerator. The average temperature inside the furnace is about 1200℃, and the front and rear arches at the throat are about 1100℃, which are high-temperature areas prone to coking.

[0035] Table 1 Experimental conditions and test results in Example 1

[0036]

[0037] Example 2

[0038] Figure 3 This is a schematic diagram of the anti-coking treatment method in Embodiment 2 of the present invention;

[0039] A refractory casting layer is arranged on the surface of the front and rear arches (red area), and an anti-coking ceramic coating is arranged on the surface of the refractory casting layer. The refractory casting layer includes 50wt% silicon carbide, 30wt% silicon oxide, 12wt% alumina, and 8% yttrium oxide. Flue gas recirculation nozzles (orange nozzles) are arranged on the left and right side walls of the incinerator. The nozzles have an orifice size of 108mm in diameter, with 4 nozzles on each side. The average temperature in the furnace is about 1200℃, and the temperature at the front and rear arches of the throat is about 1100℃, which is a high-temperature area prone to coking.

[0040] Table 2 Experimental conditions and test results in Example 2

[0041]

[0042] As can be seen from the above embodiments, the present invention provides a comprehensive method for preventing coking in a waste incinerator, including: arranging refractory bricks on the side walls of an incinerator with water-cooled furnace walls; or opening holes in the side walls of an incinerator with air-cooled furnace walls for flue gas recirculation. The present invention prevents coking by using flue gas recirculation in air-cooled furnace walls or using bricks on water-cooled furnace walls, while simultaneously spraying an anti-coking coating at the front and rear arches of the throat, thereby improving the lifespan and anti-coking and corrosion-resistant properties of the refractory materials inside the incinerator, ensuring long-term stable operation of the boiler.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A comprehensive method for preventing coking inside a waste incinerator, comprising: Refractory bricks are arranged on the side walls of the incinerator with water-cooled furnace walls; Alternatively, openings can be made in the side walls of an incinerator with air-cooled furnace walls for flue gas recirculation; Apply an anti-coking coating to the front and rear arches of the incinerator throat.

2. The comprehensive management method according to claim 1, characterized in that, The refractory bricks are composed of silicon carbide, silicon nitride, silicon dioxide, rare earth oxides, and aluminum oxide.

3. The comprehensive management method according to claim 2, characterized in that, The composition consists of 75 wt% silicon carbide, 14 wt% silicon nitride, 3 wt% silicon dioxide, 2 wt% rare earth oxides, and the balance being aluminum oxide.

4. The comprehensive management method according to claim 1, characterized in that, The thickness of the anti-coking coating is 1~2mm.

5. The comprehensive management method according to claim 1, characterized in that, The anti-coking coating comprises silicon carbide, zirconium oxide, yttrium oxide, chromium oxide, and aluminum oxide.

6. The comprehensive management method according to claim 5, characterized in that, 48 wt% silicon carbide, 15 wt% zirconium oxide, 7 wt% yttrium oxide, 25 wt% chromium oxide and balance aluminum oxide.

7. The comprehensive management method according to claim 1, characterized in that, A refractory material casting layer is provided on the radiant heating surface of the incinerator; the thickness of the refractory material casting layer is 30~50mm.

8. The comprehensive management method according to claim 7, characterized in that, The refractory casting layer includes silicon carbide, silicon oxide, aluminum oxide, and yttrium oxide.

9. The comprehensive management method according to claim 8, characterized in that, The refractory casting layer contains 50 wt% silicon carbide, 30 wt% silicon oxide, 12 wt% aluminum oxide, and 8 wt% yttrium oxide.

10. The comprehensive management method according to claim 1, characterized in that, The thickness of the refractory bricks is 40~80mm.

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