Stable combustion type low NOx incinerator

Abstract

This invention discloses a stable combustion low-NOx incinerator, comprising an incinerator body and an incinerator inlet formed thereon for the waste to be treated to enter. A pre-drying channel is connected to the incinerator inlet, and a sealable waste inlet is provided on the pre-drying channel. Inside the pre-drying channel is a conveying mechanism that feeds the waste from the waste inlet into the incinerator inlet. The pre-drying channel is equipped with a flue gas extraction pipe that extracts the combustible gas generated therefrom. The inlet of the flue gas extraction pipe is connected near the waste inlet, and its outlet is connected to the inlet end of the exhaust pipe of the incinerator body. The flue gas extraction pipe is equipped with an air supply mechanism that provides suction power. By setting up a pre-drying channel at the front end of the incinerator body and simultaneously guiding the high-temperature flue gas within the incinerator body, the waste is fully dried, achieving stable combustion within the incinerator body. This technology also exhibits strong low-NOx combustion performance.

Description

Technical Field

[0001] This invention relates to the field of waste incineration technology, and in particular to a stable-burning, low-NOx incinerator. Background Technology

[0002] The combustion process of municipal solid waste unfolds along the length of the grate: (1) Preheating, moisture evaporation, and ignition absorption in the drying and ignition section. (2) Exothermic process, mainly volatile matter combustion, in the combustion section. (3) Exothermic process, mainly fixed carbon complete combustion, in the burnout section. During the drying and ignition process, the waste is first pushed into the incinerator, absorbing the organized radiant heat from the high-temperature flue gas inside the furnace, and preheated by the primary air supplied under the grate, achieving rapid moisture evaporation. The primary air temperature is generally 200℃, and steam heating is used, which wastes high-quality energy.

[0003] In low-NOx combustion, controlled-oxygen combustion in the combustion zone is mostly employed. Numerical simulations show that although the temperature in the combustion zone is high, the oxygen content is low, resulting in less NOx generation. However, between the combustion and drying zones, and between the combustion and burnout zones, the drying and burnout zones have sufficient oxygen supply and higher temperatures, making NOx generation more likely. This is especially true for small incinerators, where in actual operation, dry and wet waste are often mixed together for combustion, resulting in low calorific value waste. Furthermore, the small processing capacity of these incinerators leads to poor combustion stability. Summary of the Invention

[0004] The purpose of this invention is to provide a stable combustion low-NOx incinerator to solve the problems existing in the prior art. A pre-drying channel is set at the front end of the incinerator body, and the waste is fully dried by the high-temperature flue gas in the incinerator body, so as to achieve stable combustion of the incinerator body. At the same time, this technology has a strong low-NOx combustion effect.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a stable combustion low NOx incinerator, including an incinerator body and an incinerator inlet formed thereon for the waste to be treated to enter. The incinerator inlet is connected to a pre-drying channel, and the pre-drying channel has a sealable waste inlet. The pre-drying channel is equipped with a conveying mechanism that sends the waste to be treated from the waste inlet into the incinerator inlet. The pre-drying channel is equipped with a flue gas suction pipe that extracts the combustible gas it generates. The inlet of the flue gas suction pipe is connected near the waste inlet, and its outlet is connected to the inlet end of the flue gas exhaust pipe of the incinerator body. The flue gas suction pipe is equipped with an air supply mechanism that provides suction power.

[0006] Preferably, the air supply mechanism is an ejector, which is divided into a contraction section, a throat and a diffusion section in sequence along the gas flow direction. The contraction section is connected to a blower that supplies hot air to it, and the blower is connected to a hot air supply mechanism. The throat and the diffusion section are connected in sequence to the flue gas extraction pipe along the flow direction of the combustible gas.

[0007] Preferably, the hot air supply mechanism is the smoke exhaust duct, and the inlet of the induced draft fan is connected to the outlet end of the smoke exhaust duct.

[0008] Preferably, the inlet end of the exhaust duct is provided with a plurality of flue gas nozzles at equal intervals along its circumference, and each flue gas nozzle is connected to the flue gas extraction duct.

[0009] Preferably, a material stacking channel is provided above the waste inlet and connected thereto, and the material stacking channel is filled with waste to be processed.

[0010] Preferably, a receiving hopper for storing waste to be processed is provided above the stacking channel, and a feeding valve that is intermittently opened between the receiving hopper and the stacking channel is provided for the waste to be processed to fall into.

[0011] Preferably, the pre-drying channel extends horizontally, and its inner bottom is provided with a first conveying grate for stepping the waste to be processed. The feeding end of the first conveying grate is correspondingly located below the waste inlet, and its discharging end is correspondingly located at the inlet of the incinerator.

[0012] Preferably, the bottom of the incinerator body is provided with a plurality of reciprocating grates that descend in stages. Each stage of the reciprocating grate extends from the incinerator inlet to the residue outlet of the incinerator body. A primary air chamber is provided below the reciprocating grate, and the primary air provided by the primary air chamber passes through the reciprocating grate and enters the incinerator body.

[0013] Preferably, a transition section is provided between the incinerator inlet and the first-stage reciprocating grate, the bottom wall of the transition section has a closed structure, and a second conveying grate for pre-dried waste is provided on the bottom wall of the transition section.

[0014] Preferably, the top of the incinerator body has a tapered structure with a cross-section that gradually decreases from bottom to top, and the flue gas duct is connected to the top of the incinerator body.

[0015] The present invention achieves the following technical effects compared to the prior art:

[0016] First, because the incinerator inlet is connected to a pre-drying channel, the waste to be treated enters the incinerator through the pre-drying channel. By setting up a flue gas extraction pipe and an air supply mechanism, a negative pressure is formed in the pre-drying channel. Under the action of the negative pressure, a portion of the high-temperature flue gas in the incinerator body flows in the opposite direction to the waste transport, thereby drying and pyrolyzing the waste in the pre-drying channel. Then, the pre-dried waste is transported to the incinerator body. The temperature fluctuation in the incinerator body is small, which ensures more stable combustion in the incinerator body. Moreover, the waste in the pre-drying channel is heated by contact with the high-temperature flue gas, and then decomposes into combustible gas. The combustible gas is sent to the exhaust pipe on the incinerator body through the flue gas extraction pipe. Since the combustible gas has a reducing atmosphere, and a large amount of NOx is generated in the incinerator body due to sufficient oxygen, the reducing property of the combustible gas is used to reduce the NOx in the exhaust pipe, thereby achieving the function of reducing NOx.

[0017] Secondly, by setting up an ejector, the induced draft fan delivers the hot air supplied by the hot air supply mechanism through the contraction section to the throat and diffuser section. The flow cross-section from the contraction section to the throat gradually decreases, so the flow velocity of the hot air increases when it flows through the throat, which reduces the air pressure at the throat. The combustible gas generated in the pre-drying channel is introduced into the throat by negative pressure, mixes with the hot air, and then passes through the diffuser section into the exhaust pipe. During the process of the combustible gas being introduced into the throat by negative pressure, it mixes with the hot air flowing into the throat at the same time, so that the combustible gas is fully preheated by the hot air. Then, after entering the exhaust pipe, it can quickly reach the temperature to react with the NOx in the exhaust pipe, so as to fully reduce NOx.

[0018] Third, the hot air supply mechanism is a smoke exhaust duct, and the inlet of the induced draft fan is connected to the outlet end of the smoke exhaust duct, so as to utilize the residual heat of the exhaust gas in the smoke exhaust duct, eliminating the need to install heating mechanisms or other pre-treatment heating of the air, thus significantly reducing energy consumption.

[0019] Fourth, the inlet end of the exhaust duct is provided with several flue gas nozzles at equal intervals along its circumference. Each flue gas nozzle is connected to the flue gas extraction duct. By setting multiple flue gas nozzles, the mixture of hot air and combustible gas is fully dispersed in the exhaust duct, so that it can fully contact the NOx in the exhaust duct and ensure the effectiveness of NOx reduction. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1This is a schematic diagram of the overall structure of the present invention;

[0022] Among them, 1-garbage inlet, 2-flue gas suction pipe, 3-recirculating flue gas pipe, 4-ejector, 5-flue gas nozzle, 6-exhaust pipe, 7-incinerator body, 8-residue outlet, 9-reciprocating grate, 10-incinerator inlet, 11-pre-drying channel, 12-conveying grate. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The purpose of this invention is to provide a stable combustion low-NOx incinerator to solve the problems existing in the prior art. A pre-drying channel is set at the front end of the incinerator body, and the waste is fully dried by the high-temperature flue gas in the incinerator body, so as to achieve stable combustion of the incinerator body. At the same time, this technology has a strong low-NOx combustion effect.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1As shown, this embodiment provides a stable combustion low-NOx incinerator, including an incinerator body 7 and an incinerator inlet 10 formed thereon for the waste to be treated to enter. A pre-drying channel 11 is connected to the incinerator inlet 10. A sealable waste inlet 1 is formed on the pre-drying channel 11, and a conveying mechanism is provided inside to feed the waste to be treated from the waste inlet 1 into the incinerator inlet 10. The conveying mechanism can use a telescopic drive rod with a push plate, so that after the waste to be treated is fully dried and pyrolyzed, the telescopic drive rod pushes the push plate to push the waste into the incinerator inlet 10. Alternatively, a conveying grate 12 can be used to progressively advance the waste. The conveying grate 12 is located inside the pre-drying channel 11 to avoid the waste being transported in stages. The gaps in the grate 12 introduce outside air, affecting the drying and preheating of the waste. The pre-drying channel 11 is equipped with a flue gas extraction pipe 2 that extracts the combustible gas it generates. The inlet of the flue gas extraction pipe 2 is connected to a position near the waste inlet 1, and its outlet is connected to the inlet end of the exhaust pipe 6 of the incinerator body 7. This utilizes the high temperature atmosphere and strong gas turbulence at the inlet end. The temperature at the inlet end of the exhaust pipe is sufficient to promote the reaction between combustible gas and NOx, while ensuring that the temperature is not too high to avoid coking and other phenomena. The inlet end temperature is preferably 800℃ to 1000℃. The flue gas extraction pipe 2 is equipped with an air supply mechanism that provides suction power. The air supply mechanism can be a blower or the like. Because the incinerator inlet 10 is connected to a pre-drying channel 11, the waste to be treated enters the incinerator through the pre-drying channel 11. By setting up a flue gas extraction pipe 2 and an air supply mechanism, a negative pressure is formed in the pre-drying channel 11. Under the action of the negative pressure, a part of the high-temperature flue gas in the incinerator body 7 flows in the opposite direction to the waste transport, thereby drying and pyrolyzing the waste in the pre-drying channel 11. Then, the pre-dried waste is transported into the incinerator body 7. The temperature fluctuation in the incinerator body 7 is small, so as to ensure more stable combustion in the incinerator body 7. Moreover, the waste in the pre-drying channel 11 is heated by contact with the high-temperature flue gas, and then decomposes into combustible gases, such as methane and CO. The combustible gases are sent into the exhaust pipe 6 on the incinerator body 7 through the flue gas extraction pipe 2. Since the combustible gases have a reducing atmosphere, and a large amount of NOx is generated in the incinerator body 7 due to sufficient oxygen, the reducing properties of the combustible gases are used to reduce the NOx in the exhaust pipe, thereby achieving the function of reducing NOx.

[0027] In a preferred embodiment of the present invention, the air supply mechanism is an ejector 4. The ejector 4 is divided into a contraction section, a throat, and a diffuser section in sequence along the gas flow direction. The flow cross section gradually decreases from the contraction section to the throat and gradually increases from the throat to the diffuser section. The contraction section is connected to an induced draft fan that supplies hot air to it. The induced draft fan is connected to a hot air supply mechanism that provides hot air. The hot air is accelerated by the induced draft fan and sent into the contraction section. The throat and the diffuser section are connected in sequence to the flue gas extraction pipe 2 along the flow direction of the combustible gas. By setting the ejector 4, the induced draft fan sends the hot air supplied by the hot air supply mechanism through the contraction section to the throat and diffuser section. The flow cross-section from the contraction section to the throat gradually decreases, so the flow velocity of the hot air increases when it flows through the throat, which reduces the air pressure at the throat. The combustible gas generated in the pre-drying channel 11 is introduced into the throat by negative pressure, mixes with the hot air, and then passes through the diffuser section into the exhaust pipe 6. During the process of the combustible gas being introduced into the throat by negative pressure, it mixes with the hot air flowing into the throat at the same time, so that the combustible gas is fully preheated by the hot air. Then, after entering the exhaust pipe 6, it can quickly reach the temperature to react with the NOx in the exhaust pipe, so as to fully reduce NOx.

[0028] Furthermore, the hot air supply mechanism is a flue gas duct, and the inlet of the induced draft fan is connected to the outlet end of the flue gas duct 6. It is also connected to the converging section of the ejector 4 through the recirculated flue gas duct 3, so as to utilize the residual heat of the exhaust gas in the flue gas duct 6, eliminating the need for pre-heating of the air by heating mechanisms, thus significantly reducing energy consumption. In a preferred embodiment of the present invention, the induced draft fan is a variable frequency fan, and a NOx detector is provided at the outlet of the flue gas duct to detect the emitted NOx, thereby adjusting the induced draft fan in real time to regulate the airflow of combustible gas and recirculated flue gas entering the flue gas duct, achieving real-time adjustment of NOx treatment.

[0029] Furthermore, the inlet end of the exhaust duct 6 is provided with several flue gas nozzles 5 at equal intervals along its circumference. Each flue gas nozzle 5 is connected to the flue gas extraction duct 2. By setting multiple flue gas nozzles 5, the mixture of hot air and combustible gas is fully dispersed in the exhaust duct 6, thereby ensuring sufficient contact with NOx in the exhaust duct 6 and guaranteeing the effectiveness of NOx reduction. Preferably, the flow cross-section of the flue gas nozzles 5 gradually decreases along the gas flow direction to accelerate the flow of combustible gas and increase the turbulence intensity at the exhaust duct 6.

[0030] In a preferred embodiment of the present invention, a stacking channel is provided above the garbage inlet 1 and is connected to it. The stacking channel is filled with garbage to be processed. That is, the stacking channel is located in front of the inlet of the flue gas extraction pipe 2. By accumulating garbage to be processed in the stacking channel, the front end of the garbage inlet 1 is blocked by the garbage to be processed, so as to avoid the risk of easy leakage of combustible gas when garbage is filled again.

[0031] To further reduce the risk of connection between the pre-drying channel 11 and the outside world, a receiving hopper for storing waste to be processed is provided above the stacking channel. A feed valve that opens intermittently between the receiving hopper and the stacking channel allows waste to be processed to fall into the channel. The feed valve is opened when refilling to facilitate the introduction of waste. When pyrolyzing the waste in the pre-drying channel 11, the waste inlet 1 is sealed to prevent outside air from entering the pre-drying channel 11 through the waste inlet 1 and affecting the pyrolysis effect of the waste.

[0032] When installing the conveying mechanism in the pre-drying channel 11, the push plate and telescopic drive rod mechanism can easily cause the waste to get stuck. Moreover, if the processed waste is pushed into the incinerator body 7 in a timed and quantitative manner, too much waste can be fed into the incinerator at one time, which can easily affect the incineration of waste. Therefore, the pre-drying channel 11 is preferably horizontally extended, and its inner bottom is provided with a first conveying grate 12 for stepping the waste to be processed. The feed end of the first conveying grate 12 is located below the waste inlet 1, and its discharge end is located at the incinerator inlet 10. The first conveying grate 12 is a reciprocating conveying grate 12, and its reciprocating drive mechanism is located below the first conveying grate 12 to achieve slow stepping of the waste. This not only ensures that the waste to be processed is fully dried and pyrolyzed, but also gradually fills the incinerator body 7 with waste, ensuring the combustion effect in the incinerator body 7.

[0033] Furthermore, the bottom of the incinerator body 7 is provided with several progressively descending reciprocating grates 9. Each level of the reciprocating grate 9 extends from the incinerator inlet 10 to the residue outlet 8 of the incinerator body 7. A primary air chamber is provided below the reciprocating grate 9. The primary air provided by the primary air chamber passes through the reciprocating grate 9 and enters the incinerator body 7. The waste is stepped by the reciprocating grate 9, and the waste is burned and completely burned on the reciprocating grate 9 to achieve complete combustion and degradation of the waste.

[0034] Furthermore, a transition section is provided between the incinerator inlet 10 and the first-stage reciprocating grate 9. The bottom wall of the transition section has a closed structure, and a second conveying grate 12 for pre-dried waste is provided on the bottom wall of the transition section. By setting the transition section, the distance between the reciprocating grate 9 and the incinerator inlet 10 is increased, avoiding the situation where the distance is too small, which could easily cause a large amount of primary air to enter the pre-drying channel 11 through the incinerator inlet 10, affecting the pre-treatment of waste.

[0035] Preferably, the top of the incinerator body 7 has a tapered structure with a cross-section that gradually decreases from bottom to top, and the flue gas duct 6 is connected to the top of the incinerator body 7. By setting the top of the incinerator to a tapered structure, the remaining flue gas in the incinerator can quickly accumulate at its top and then flow into the flue gas duct 6, thereby achieving full degradation of NOx.

[0036] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0037] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0038] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A stable combustion type low NOx incinerator, characterized by, The incinerator includes an incinerator body and an incinerator inlet formed thereon for the waste to be processed to enter. The incinerator inlet is connected to a pre-drying channel. The pre-drying channel has a sealable waste inlet and is equipped with a conveying mechanism inside to send the waste to be processed from the waste inlet into the incinerator inlet. The pre-drying channel is equipped with a flue gas suction pipe that extracts the combustible gas it generates. The inlet of the flue gas suction pipe is connected to a position near the waste inlet, and its outlet is connected to the inlet end of the flue gas exhaust pipe of the incinerator body. The flue gas suction pipe is equipped with an air supply mechanism that provides suction power. The air supply mechanism is an ejector, which is divided into a contraction section, a throat, and a diffuser section along the gas flow direction. The contraction section is connected to an induced draft fan that supplies hot air to it. The induced draft fan is connected to a hot air supply mechanism. The throat and the diffuser section are connected to the flue gas extraction pipe along the flow direction of the combustible gas. The hot air supply mechanism is the exhaust pipe, and the inlet of the induced draft fan is connected to the outlet end of the exhaust pipe. Above the waste inlet is a material stacking channel connected to it, and the material stacking channel is filled with waste to be processed.

2. The stable combustion type low NOx incinerator according to claim 1, characterized by The inlet end of the exhaust duct is provided with a number of flue gas nozzles at equal intervals along its circumference, and each of the flue gas nozzles is connected to the flue gas extraction duct.

3. The stable combustion type low NOx incinerator according to claim 2, characterized by Above the material stacking channel is a receiving hopper for storing waste to be processed, and between the receiving hopper and the material stacking channel is a feeding valve that opens intermittently to allow waste to be processed to fall.

4. The stable combustion type low NOx incinerator according to claim 3, characterized by The pre-drying channel extends horizontally, and its inner bottom is provided with a first conveying grate for stepping the waste to be processed. The feeding end of the first conveying grate is located below the waste inlet, and its discharging end is located at the inlet of the incinerator.

5. The stable combustion type low NOx incinerator according to claim 4, characterized by The bottom of the incinerator body is provided with several reciprocating grates that descend in stages. Each stage of the reciprocating grate extends from the incinerator inlet to the slag outlet of the incinerator body. A primary air chamber is provided below the reciprocating grate, and the primary air provided by the primary air chamber passes through the reciprocating grate and enters the incinerator body.

6. The stable combustion type low NOx incinerator according to claim 5, characterized by A transition section is provided between the incinerator inlet and the first-stage reciprocating grate. The bottom wall of the transition section has a closed structure, and a second conveying grate for pre-dried waste is provided on the bottom wall of the transition section.

7. The stable combustion type low NOx incinerator according to claim 6, characterized by The top of the incinerator body has a tapered structure with a cross-section that gradually decreases from bottom to top, and the exhaust pipe is connected to the top of the incinerator body.

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