Furnace wall for inhibiting coking of garbage incinerator

Abstract

The utility model discloses a furnace wall for inhibiting coking of a garbage incinerator. The furnace wall comprises a water cooling wall, the refractory material layer is laid on the inner wall surface of the water cooling wall and comprises a lower refractory material layer with a relatively high heat conductivity coefficient and an upper refractory material layer with a relatively low heat conductivity coefficient; the air cannon is arranged at an outlet of the incinerator and is used for spraying compressed gas into the incinerator so as to destroy a coking sample; and the peripheral air spraying pipes are arranged at the bottoms of the front arch and the rear arch and used for spraying peripheral air flow into the furnace.

Description

Technical Field

[0001] The utility model relates to a waste incinerator, in particular to a furnace wall for suppressing coking of a waste incinerator, and belongs to the technical field of waste treatment equipment. Background Art

[0002] By using the incineration method to treat domestic waste, the reduction and harmless treatment of urban domestic waste can be realized; at the same time, since the waste heat generated by waste incineration can also be used for power generation, the resource treatment of waste is also realized. However, it is found in actual operation that due to the complexity, variability and particularity of the waste composition, coking often occurs in the waste incinerator, which affects the long-term stable operation of the waste power plant.

[0003] During the waste combustion process, many low-melting inorganic substances, compounds and eutectics will be generated. This part of the substances presents a molten state in the high-temperature furnace, resulting in increased viscosity and enhanced agglomeration. They are adsorbed on the heated wall surface and continuously gather and grow. At the same time, the initial flow state of fly ash particles in the furnace is also destroyed, making the fly ash easier to stay in the low-speed area, and finally leading to the formation of coking.

[0004] Coking will increase the wall thickness of the heated surface and the thermal resistance, resulting in an increase in the local heat load and the wall temperature exceeding the limit; the growth of the coke sample will change the internal structure of the furnace, resulting in uneven distribution of the air flow field in the furnace, causing the flame to deflect and affecting the combustion in the furnace; the large coke sample will reduce the flow area in the furnace, resulting in an increase in the flue gas temperature of the furnace and a decrease in the boiler efficiency. More seriously, the falling of large slag samples may also cause the grate at the bottom of the furnace to be damaged; at the same time, coking will also exacerbate the wall surface wear and corrosion, resulting in a thinner pipe wall. In severe cases, it may cause pipe explosion and abnormal shutdown of the furnace. Content of the Utility Model

[0005] In order to solve the above problems, the utility model provides a furnace wall for suppressing coking of a waste incinerator, so as to avoid affecting the long-term safe and stable operation of the boiler due to coking.

[0006] A furnace wall for suppressing coking of a waste incinerator includes: a water-cooled wall; a refractory material layer laid on the inner wall surface of the water-cooled wall, including a lower refractory material layer with a higher thermal conductivity and an upper refractory material layer with a lower thermal conductivity; an air cannon arranged at the outlet position of the incinerator and used to spray compressed gas into the furnace to break the coke sample; and a perimeter air nozzle arranged at the bottom of the front arch and the rear arch and used to spray perimeter air flow into the furnace.

[0007] The beneficial effects of the technical solution of the utility model are embodied in the following aspects: the utility model proposes a furnace wall for inhibiting coking of a garbage incinerator, and two refractory materials with different thermal conductivity are laid on the inner side of the water-cooled wall. Since the thermal conductivity of the lower castable is relatively high, the temperature of the lower flue gas can be effectively reduced, and the risk of coking in the furnace can be reduced. At the same time, since the garbage incinerator has a standard of 850℃ / 2s (the residence time of the flue gas in the combustion chamber should not be less than 2s under the condition of not less than 850℃), the upper castable adopts a corundum mullite castable with a lower thermal conductivity. The two castables are used in combination to protect the The water-cooled wall tube screen can slow down the coking speed of the incinerator while meeting the 850℃ / 2s standard of the incinerator. After the initial coking layer of the front and rear arches is formed and a large coking sample is produced, an air cannon can be used to eject gas at high speed under the action of pressure difference. The high kinetic energy airflow can destroy the coking sample and avoid the deterioration of wall coking. At the same time, the peripheral wind nozzle is opened for a long time to spray the peripheral wind airflow with a faster speed. The faster airflow has greater rigidity. When the airflow flows on the front and rear arch walls, it can inhibit the formation of the initial coking layer during the garbage coking process and remove the smaller coke samples. In summary, under the joint action of the castables with different thermal conductivity in the upper and lower parts, water-cooled walls, air cannons and peripheral wind nozzles, the coking of the garbage incinerator can be effectively inhibited.

[0008] Furthermore, the water-cooled wall is a membrane water-cooled wall.

[0009] Furthermore, the lower refractory material layer is located from the incinerator throat area to a first preset height, and the upper refractory material layer is located from the first preset height to the flue outlet. Furthermore, the first preset height is 20.8 meters above the incinerator.

[0010] Furthermore, the lower refractory material layer is made of silicon carbide castable, and the upper refractory material layer is made of corundum mullite castable. Furthermore, the silicon carbide castable is laid with a thickness of 10mm-100mm, and the corundum mullite castable is laid with a thickness of 10mm-100mm.

[0011] Furthermore, one air cannon is provided on each side of the incinerator outlet; the air cannon comprises: a gas storage tank fixed to the outside of the furnace wall, an air jet pipe connected to the gas storage tank and extending into the furnace, an electromagnetic quick-closing valve provided on the pipeline of the air jet pipe, and a controller; the gas storage tank is used to store compressed gas, and the controller is used to control the opening / closing of the electromagnetic quick-closing valve. Furthermore, the portion of the air jet pipe in the furnace is an elbow, with the bending direction facing downward.

[0012] Further, a first perimeter air injection pipe is arranged at the bottom of the front arch, and a second perimeter air injection pipe is arranged at the bottom of the rear arch. The first perimeter air injection pipe bends upward near the inner wall of the front arch inside the furnace, and the second perimeter air injection pipe bends upward near the inner wall of the rear arch inside the furnace.

[0013] Further, the furnace wall further includes: a leachate spraying device, which is arranged at the tail of the water-cooled wall on the rear arch side and is used to spray leachate of garbage onto the grate in the incinerator to reduce the internal temperature of the furnace chamber. Through this further technical solution, when the internal temperature of the furnace chamber exceeds 1250 °C, the leachate spraying device is turned on to spray leachate of garbage onto the grate, slow down the garbage combustion rate, reduce the internal temperature of the furnace chamber, and inhibit the formation of coke samples under high-temperature conditions. Description of the Drawings

[0014] Figure 1 It is a schematic diagram of the furnace wall layout for suppressing coking of a garbage incinerator according to an embodiment of the present invention.

[0015] Description of the reference numerals: 1 - membrane water-cooled wall; 2 - upper refractory layer (corundum-mullite castable); 3 - lower refractory layer (silicon carbide castable); 4 - air cannon; 5 - perimeter air injection pipe; 6 - leachate spraying device. Detailed Embodiments

[0016] The present invention will be further described below in conjunction with the drawings, specific embodiments, and examples. The purpose of providing the examples is only for illustration and not for any limitation. In addition, for the spatial orientation terms such as "upper", "lower", "left", "right", "top", and "bottom" used in the description of the technical solution of the present invention, they are convenient for describing the relative positional relationship between the components of the product, and do not represent that the product has only the orientation shown in the figure. During the actual use process, as the orientation of the product changes, the spatial-related descriptions used to describe its orientation should also be explained in a similar way. In addition, terms such as "first" and "second" are only used to distinguish components, and it should be understood that these components should not be limited by such terms. They do not inherently mean that these elements have the aforementioned ordinal numbers, nor do they represent the arrangement order of one component and another component or the order in the manufacturing method.

[0017] Please refer to Figure 1, an embodiment of the present utility model provides a furnace wall for suppressing coking in a waste incinerator. The furnace wall includes: a membrane water wall 1, an upper refractory layer 2 and a lower refractory layer 3 laid on the inner side surface of the membrane water wall 1, an air cannon 4, a perimeter air nozzle 5, and a leachate spraying device 6. Among them, the lower refractory layer 3 has a relatively high thermal conductivity, while the upper refractory layer 2 has a relatively low thermal conductivity. Specifically, from above the throat area of the incinerator to an elevation of 20.8 meters, it is a silicon carbide corrosion-resistant castable with good thermal conductivity, and from an elevation of 20.8 meters upwards to the flue outlet, it is a corundum-mullite wear-resistant castable with relatively weak thermal conductivity. The air cannon 4 is arranged at the outlet position of the incinerator, and an air cannon is respectively arranged at the connection of the flue with the front arch and the rear arch. The function of the air cannon is to generate a strong high-speed jet of air along the wall surface to break the coking sample when a relatively large coking sample is formed after the initial coking layer is formed on the front and rear arches, so as to avoid the deterioration of wall coking. There are also two perimeter air nozzles 5, namely: a first perimeter air nozzle arranged at the bottom of the front arch and a second perimeter air nozzle arranged at the bottom of the rear arch. The first perimeter air nozzle bends upwards near the inner wall of the front arch in the furnace, and the second perimeter air nozzle bends upwards near the inner wall of the rear arch in the furnace. The perimeter air nozzle 5 is always open, and its function is to respectively spray a relatively fast perimeter air flow towards the front and rear arch wall surfaces. The relatively fast air flow has greater rigidity, and when the air flow flows on the front and rear arch wall surfaces, it can inhibit the formation of the initial coking layer during the waste coking process and remove relatively small coking samples. The leachate spraying device 6 is arranged at the tail of the water wall on the side of the rear arch, and the spraying medium is the leachate collected during the waste fermentation process. The spraying direction is towards the grate in the incinerator. When the internal temperature of the furnace exceeds 1250 °C, the leachate spraying device is turned on to spray the leachate on the grate, slow down the waste combustion rate, reduce the internal temperature of the furnace, and inhibit the formation of coking samples at high temperatures.

[0018] In some specific embodiments, the air cannon 4 includes a gas storage tank, a spray pipe, an electromagnetic quick shut-off valve, and a controller; the gas storage tank is used to store compressed gas and can be fixed on the outer side of the furnace wall; one end of the spray pipe is connected to the gas storage tank and the other end extends into the furnace, and the part extending into the furnace is an elbow with a downward bending direction; the electromagnetic quick shut-off valve is arranged on the pipeline of the spray pipe, and the opening / closing of the electromagnetic quick shut-off valve is controlled by the controller to control the operation of the air cannon. When the air cannon needs to work, the electromagnetic quick shut-off valve is controlled to open, and the compressed gas in the gas storage tank forms a strong high-speed jet of air under the action of the pressure difference. The high-kinetic-energy air can break the coking sample and avoid the deterioration of wall coking. When the air cannon does not need to work, the electromagnetic quick shut-off valve is controlled to close.

[0019] In a specific embodiment, taking the 400-ton-per-day incinerator of a waste power plant as an example, the incinerator has a water-cooled furnace chamber. To ensure the safe operation of the water-cooled wall, corundum-mullite castable 2 and silicon carbide castable 3 are laid on the surface. The two are combined and rationally distributed to form a structure for suppressing coking in the 400-ton-per-day waste incinerator. Important parameters such as ash softening temperature are obtained through chemical analysis to define the temperature range in which coking occurs in the incinerator. The thickness and area of the two castables are calculated based on their physical and chemical properties. In this example, the laying thickness of both castables is in the range of 10 mm - 100 mm, and the laying area is in the range of 10 m 2 - 100 m 2 2. Controlling the area and thickness of the surface castable can keep the temperature range of the lower vertical flue below the coking temperature range and meet the standard of 850 °C / 2 s for flue gas indicators at the same time. In this example, by the cooperation of two castables with different thermal conductivities, the temperature of the vertical flue can be controlled to meet the flue gas temperatures under different working conditions of boilers with different capacities, so that the flue gas temperature operates in a reasonable range. At the same time, when a large coking sample is generated after the initial coking layer is formed on the front and rear arches, the air cannon 4 can use the air cannon device to make the compressed air in the air storage tank form a strong airflow with high speed under the action of pressure difference. The high-kinetic-energy air can destroy the coking sample and prevent the deterioration of wall coking. The perimeter air nozzle 5 is arranged at the bottom of the front and rear arches, using the airflow with higher speed and greater rigidity to inhibit the formation of the initial coking layer during the waste coking process and remove the coking samples with smaller volume; the leachate spraying device 6 is arranged at the tail of the membrane water-cooled wall, and the spraying medium is the leachate collected during the waste fermentation process. The spraying direction is the grate in the incinerator. When the temperature inside the furnace chamber exceeds 1250 °C, the leachate spraying device is turned on to spray the leachate on the grate, slowing down the waste combustion rate and reducing the temperature inside the furnace chamber.

[0020] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those skilled in the technical field to which the present invention belongs, without departing from the concept of the present invention, several equivalent substitutions or obvious modifications can be made, and as long as the performance or use is the same, they should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A furnace wall for inhibiting coking of a garbage incinerator, characterized in that: include: Water wall; A refractory material layer is applied on the inner wall surface of the water-cooled wall, comprising a lower refractory material layer with a higher thermal conductivity and an upper refractory material layer with a lower thermal conductivity; Air cannon, installed at the incinerator outlet, is used to spray compressed gas into the furnace to destroy the coke sample; as well as The peripheral air nozzle is arranged at the bottom of the front arch and the rear arch, and is used to spray the peripheral air flow into the furnace.

2. The furnace wall according to claim 1, characterized in that: The water-cooled wall is a membrane-type water-cooled wall.

3. The furnace wall according to claim 1, characterized in that: The lower refractory material layer is located from the throat area of ​​the incinerator to a first preset height, and the upper refractory material layer is located from the first preset height to the flue outlet.

4. The furnace wall according to claim 3, characterized in that: The first preset height is 20.8 meters above the incinerator.

5. The furnace wall according to any one of claims 1 to 4, characterized in that: The lower refractory material layer is made of silicon carbide castable material, and the upper refractory material layer is made of corundum mullite castable material.

6. The furnace wall according to claim 5, characterized in that: The silicon carbide castable is laid with a thickness of 10 mm to 100 mm, and the corundum mullite castable is laid with a thickness of 10 mm to 100 mm.

7. The furnace wall according to claim 1, characterized in that: An air cannon is arranged on each side of the incinerator outlet; the air cannon comprises: a gas storage tank fixed on the outer side of the furnace wall, an injection pipe connected to the gas storage tank and extending into the furnace, an electromagnetic quick-closing valve arranged on the pipeline of the injection pipe, and a controller; the gas storage tank is used to store compressed gas, and the controller is used to control the opening / closing of the electromagnetic quick-closing valve.

8. The furnace wall according to claim 7, characterized in that: The portion of the gas injection pipe in the furnace is an elbow, and the bending direction is downward.

9. The furnace wall according to claim 1, characterized in that: A first peripheral air nozzle is arranged at the bottom of the front arch, and a second peripheral air nozzle is arranged at the bottom of the rear arch. The first peripheral air nozzle is bent upward near the inner wall of the front arch in the furnace, and the second peripheral air nozzle is bent upward near the inner wall of the rear arch in the furnace.

10. The furnace wall according to claim 1, characterized in that: Also includes: The leachate spraying device is arranged at the tail end of the water-cooled wall on the rear arch side and is used to spray garbage leachate onto the combustion grate in the incinerator to reduce the internal temperature of the furnace.

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