One-pit-three-furnace type urban domestic waste incinerator air and flue gas system

Abstract

The present invention discloses a wind and smoke system for a one-pit three-furnace type municipal domestic waste incinerator, which relates to a waste incineration treatment system and includes a waste storage pit. The waste storage pit is connected through pipelines to a deodorization device I, a deodorization device II, a primary air blower I, a primary air air preheater I, an incineration boiler I, a primary air blower II, a primary air air preheater II, an incineration boiler II, a primary air blower III, a primary air air preheater III, and an incineration boiler III. A fresh air blower device is also connected to the pipeline, and the fresh air blower device is connected to the primary air air preheater I and the primary air air preheater II. Outlet isolation baffles are movably arranged on both the fresh air outlet pipeline I and the fresh air outlet pipeline II; mechanical grates are arranged at the bottoms of the incineration boiler I, the incineration boiler II, and the incineration boiler III, and waste heat boilers are arranged at the tops of the incineration boiler I, the incineration boiler II, and the incineration boiler III. A economizer is arranged at the end of the waste heat boiler, and the outlet of the economizer is connected to a tail gas treatment device, having the advantages of high operating reliability of the primary air system and improved economic benefits.

Description

Technical Field

[0001] The invention relates to a garbage incineration treatment system, in particular to an air and smoke system of a one-pit three-furnace type urban domestic garbage incinerator. Background Art

[0002] The general process flow of the flue gas system of a municipal solid waste incinerator is as follows: the primary fan extracts the odor from the garbage pit, which enters the wind chambers under the grate after being heated by the primary air preheater, and then enters the incinerator through the air holes on the grate. The primary air dries and assists the combustion of the garbage on the grate; the flue gas generated after the garbage is burned enters the flue of the waste heat boiler and is denitrated by the SNCR device; then it flows through other flues of the waste heat boiler and finally enters the deacidification tower from the economizer outlet of the waste heat boiler; the acidic gas in the flue gas is removed by the deacidification tower, and the flue gas passes through the activated carbon injection device arranged in the pipeline between the economizer outlet and the deacidification tower to adsorb dioxins and heavy metals in the flue gas; then the flue gas enters the dust collector for filtration The particulate matter in the flue gas; then the clean flue gas coming out of the dust collector is heated by SGH steam and enters the SCR denitrification device. The clean flue gas that meets the emission standards is discharged into the atmosphere from the chimney through the induced draft fan; however, in the existing flue gas system of domestic waste incinerators, when the boiler is cold started, it is affected by the upper limit temperature of the heat resistance of the grate material. Generally, the flue gas temperature is started before 350℃ and the primary fan is started to cool the grate. Otherwise, the grate will expand unevenly and cause the grate to warp, which will affect the service life of the grate. In severe cases, the furnace will be forced to be stopped for replacement; according to the research of scholars such as Bai Liangcheng, when the flue gas temperature in the furnace reaches 700℃ and stays for 0.5 seconds, the complete decomposition of dioxins and odors can be achieved. Meet the flue gas emission requirements; when the boiler is cold started, start the primary fan before the flue gas temperature reaches 350℃, and draw the odor from the garbage pit into the furnace. According to the furnace start-up temperature table, the furnace temperature rises from 350℃ to 700℃, and each time takes 5-6 hours. The odor entering the boiler during this period is not completely decomposed; the flue gas is only filtered by the dust collector and adsorbed by activated carbon, and then discharged into the atmosphere from the chimney through the induced draft fan, which poses a risk of environmental pollution. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a one-pit, three-furnace urban domestic waste incinerator air and smoke system, which has the advantages of improving the operating reliability of the primary air system, reducing fault downtime, and improving economic benefits.

[0004] To achieve the above object, the present invention adopts the following technical solutions: A wind and smoke system for a one-pit-three-furnace type municipal domestic waste incinerator, including a waste storage pit, the waste storage pit is sequentially connected with a primary fan I, a primary air air preheater I, and an incineration boiler I through pipeline I; the waste storage pit is sequentially connected with a primary fan II, a primary air air preheater II, and an incineration boiler II through pipeline II; the waste storage pit is sequentially connected with a primary fan III, a primary air air preheater III, and an incineration boiler III through pipeline III; the waste storage pit is also connected with a deodorization device I and a deodorization device II; the incineration boiler I, incineration boiler II, and incineration boiler III are connected with a tail gas treatment device, an induced draft fan, and a chimney; a fresh air fan device is also connected between pipeline I, pipeline II, and pipeline III, the fresh air fan device includes a fresh air fan, the air inlet end of the fresh air fan is communicated with the outside air through a fresh air inlet pipeline, a filter screen and a muffler are sequentially arranged on the fresh air inlet pipeline along the air flow direction, the air outlet end of the fresh air fan is respectively connected with the primary air air preheater I, the primary air air preheater II, and the primary air air preheater III through a fresh air outlet pipeline I, a fresh air outlet pipeline II, and a fresh air outlet pipeline III, and air outlet isolation baffles are movably arranged on the fresh air outlet pipeline I, the fresh air outlet pipeline II, and the fresh air outlet pipeline III; mechanical grate and slag extractor are arranged at the bottom of the incineration boiler I, incineration boiler II, and incineration boiler III, the top of the incineration boiler I, incineration boiler II, and incineration boiler III is an outlet waste heat boiler, a combined flue is arranged in the outlet waste heat boiler, a economizer is arranged at the end of the outlet waste heat boiler, and the outlet of the economizer is connected with the tail gas treatment device.

[0005] To further optimize the present invention, the following technical solutions can be preferably selected:

[0006] Preferably, the tail gas treatment device includes a deacidification tower, a dust collector, an SGH steam heater, and an SCR flue gas denitration reaction tower connected in sequence.

[0007] Preferably, rubber expansion joints I are respectively arranged on the pipelines at the air inlet end and the air outlet end of the fresh air fan.

[0008] Preferably, electric regulating baffles are arranged at the air inlet end and the air outlet end of the fresh air fan.

[0009] Preferably, the combined flue includes a vertical flue I, a vertical flue II, a vertical flue III, and a horizontal flue connected in sequence, and the vertical flue I, the vertical flue II, and the vertical flue III form an S-shaped flue.

[0010] Preferably, the incineration boilers I, II, and III are also connected to a secondary fan device, which includes a secondary fan. Rubber expansion joints II are respectively arranged on the inlet and outlet pipelines of the secondary fan, and the outlet end of the secondary fan is connected to the incinerator through a primary air air preheater.

[0011] Preferably, ignition fans I, II, an auxiliary combustion fan, and a cooling fan are also arranged in parallel on the incineration boilers I, II, and III. Rubber expansion joints III are arranged at the inlet ends of the ignition fans I, II, the auxiliary combustion fan, and the cooling fan.

[0012] Preferably, the deodorization devices I and II each include a deodorization device inlet filter screen, a deodorization device inlet electric door, an activated carbon adsorption device, and an explosion-proof deodorization fan that are connected in sequence.

[0013] The beneficial effects of the present invention are as follows: The one-pit-to-three-furnace mode of the flue gas system of this waste incinerator is applicable to the situation where 1 waste pit corresponds to 3 waste incinerators; a fresh air fan device is configured in this flue gas system to provide fresh air for boiler combustion during cold start and shutdown of the boiler; it can be used as a standby fan for the primary fan of any incinerator; a filter screen is arranged at the inlet of the fresh air fan to filter impurities in the air, and rubber expansion joints are respectively arranged on the inlet and outlet pipelines of the fresh air fan to compensate for and absorb axial, lateral, and angular thermal deformations of the pipeline; absorb equipment vibration and reduce the impact of equipment vibration on the pipeline; absorb the deformation amount of the pipeline caused by earthquakes and ground subsidence. Outlet isolation baffles are movably arranged on the fresh air outlet pipelines I and II to isolate the fresh air pipeline and the primary air pipeline, ensuring that the odor in the primary air pipeline is isolated after the fresh air fan stops operating, preventing the odor from flowing back into the fresh air fan and thus polluting the atmospheric environment. Description of the Drawings

[0014] Figure 1 It is a structural schematic diagram of a new one-pit-three-furnace incinerator flue gas system;

[0015] Figure 2 It is a structural schematic diagram of the original one-pit-three-furnace incinerator flue gas system:

[0016] Figure 3 It is a structural schematic diagram of the incinerator;

[0017] Figure 4 It is an enlarged schematic diagram of the structure at A;

[0018] Figure 5 It is an enlarged schematic diagram of the structure at B.

[0019] Among them, 1 - garbage storage pit, 2 - primary air fan I, 3 - incineration boiler I, 4 - acid removal tower, 5 - dust collector, 6 - SGHe steam heater, 7 - SCR flue gas denitrification equipment, 8 - induced draft fan, 9 - vertical flue I, 10 - vertical flue II, 11 - vertical flue III, 12 - horizontal flue, 13 - economizer, 14 - ignition fan I, 15 - auxiliary combustion fan, 16 - cooling fan, 17 - mechanical grate, 18 - secondary air fan, 19 - ignition fan II, 20 - fresh air fan, 21 - filter screen, 22 - silencer, 23 - electric regulating baffle, 24 - outlet isolation baffle, 25 - primary air preheater I, 26 - incineration boiler II, 27 - fresh air outlet duct I, 28 - fresh air outlet duct II, 29 - primary air fan II, 30 - duct I, 31 - duct II, 32 - incineration boiler III, 33 - duct III, 34 - fresh air outlet duct III, 35 - primary air fan III, 36 - electric door at the inlet of the deodorization device, 37 - activated carbon adsorption device, 38 - explosion-proof deodorization fan, 39 - filter screen at the inlet of the deodorization device, 40 - SNCR denitrification device. Detailed implementation manners

[0020] Problems existing in the original design of the primary air system of existing urban domestic waste incinerators

[0021] 1. When the boiler is started in cold state in the original design, affected by the heat-resistant upper limit temperature of the grate bar material, the primary air fan ② is generally started when the flue gas temperature is before 350°C to cool the grate bar. Otherwise, the grate bar will expand unevenly, causing the grate bar to warp, affecting the service life of the grate, and in severe cases, forced to stop the furnace for replacement; According to the research of scholars such as Bai Liangcheng, when the flue gas temperature in the furnace reaches 700°C and stays for 0.5 seconds, the complete decomposition of dioxins and odors can be achieved to meet the flue gas emission requirements; When the boiler is started in cold state, the primary air fan ② is started before the flue gas temperature reaches 350°C, and the odor is drawn from the garbage pit into the furnace. According to the furnace start-up temperature rise table, during the process of the furnace temperature rising from 350°C to 700°C, each time it takes up to 5 - 6 hours, and the odor entering the boiler during this time period is not completely decomposed; The flue gas is only filtered by the dust collector and adsorbed by activated carbon, and then discharged into the atmosphere from the chimney through the induced draft fan, posing a potential environmental pollution hazard.

[0022] 2. For the original designed boiler, shutdown maintenance or grate maintenance requires boiler shutdown. During the shutdown process, before the garbage is completely burned out, it is required to maintain the furnace temperature above 850 °C to meet the requirement for dioxin decomposition. When the garbage on the grate becomes less, the oil gun must be started to maintain the furnace temperature at 850 °C. Only after the garbage is completely burned out can the furnace be shut down and cooled down. During the shutdown process, the temperature of the grate bars is relatively high, and the primary air fan must be kept running to cool the grate bars. The primary air fan extracts the odor from the garbage pit and continuously enters the furnace until the furnace temperature drops below 300 °C. During this process, there is a hidden danger that the odor is not completely burned and decomposed, causing environmental pollution. Moreover, after the boiler is shut down and the furnace meets the maintenance conditions, when the manhole for grate furnace maintenance is opened for ventilation, the odor is relatively strong, the working environment inside the furnace for maintenance is poor, and it pollutes the working environment of the boiler room.

[0023] 3. When the original designed boiler is operating normally, if the primary air fan has a serious fault due to its own reasons and cannot be started in a short time, and there is no standby primary air fan, it is easy to cause the flue gas index to exceed the standard, and the boiler can only be forced to shut down for maintenance. Shutting down and starting up the boiler will affect the service life of the boiler and cause economic losses to the enterprise.

[0024] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] Embodiment 1:

[0027] As Figures 1 to 5As shown in the figure, a flue gas system for a one-pit three-furnace municipal domestic waste incinerator includes a waste storage pit 1. The waste storage pit 1 is sequentially connected to a primary air blower I 2, a primary air air preheater I 25, and an incineration boiler I 3 through a pipeline I 30; the waste storage pit is sequentially connected to a primary air blower II, a primary air air preheater II, and an incineration boiler II 26 through a pipeline II 31; the waste storage pit 1 is also connected to a deodorization device I and a deodorization device II. Both the deodorization device I and the deodorization device II include a deodorization device inlet filter screen 39, a deodorization device inlet electric door 36, an activated carbon absorption device 37, and an explosion-proof deodorization blower 38 connected in sequence. The deodorization device I and the deodorization device II are installed on both sides of the waste storage pit 1. Its function is to start the deodorization blower device when all the waste pit incinerators are shut down, maintain the negative pressure in the waste pit, and prevent the odor in the waste pit from overflowing; the waste storage pit is sequentially connected to a primary air blower III 35, a primary air air preheater III, and an incineration boiler III 32 through a pipeline III 33; the incineration boiler I 3, the incineration boiler II 26, and the incineration boiler III 32 are connected to a tail gas treatment device, an induced draft fan 8, and a chimney. A fresh air blower device is also connected between the pipeline I 30, the pipeline II 31, and the pipeline III 33 to provide fresh air for boiler combustion during cold start and shutdown of the boiler; as a standby fan for the primary air blower; the fresh air blower device includes a fresh air blower. The air inlet end of the fresh air blower is connected to the outside air through a fresh air inlet pipeline. A filter screen 21 and a muffler 22 are sequentially installed on the fresh air inlet pipeline along the air flow direction. The muffler can reduce the fluid noise during the operation of the blower, and the filter screen pre-treats the air of the fresh air blower to filter impurities in the air; the air outlet end of the fresh air blower 20 is respectively connected to the primary air air preheater I 25, the primary air air preheater II, and the primary air air preheater III through a fresh air outlet pipeline I 27, a fresh air outlet pipeline II 28, and a fresh air outlet pipeline III 35. Air outlet isolation baffles 24 are movably arranged on the fresh air outlet pipeline I, the fresh air outlet pipeline II, and the fresh air outlet pipeline III 35; isolate the fresh air pipeline and the primary air pipeline; after the fresh air blower is shut down, isolate the odor in the primary air pipeline to prevent the odor from flowing back into the fresh air blower and further polluting the atmospheric environment. Rubber expansion joints I are respectively installed on the pipelines at the air inlet end and the air outlet end of the fresh air blower to compensate for and absorb the axial, lateral, and angular thermal deformations of the pipeline; absorb equipment vibration and reduce the influence of equipment vibration on the pipeline; absorb the deformation amount of the pipeline caused by earthquakes and ground subsidence; electric regulating baffles 23 are installed at both the air inlet end and the air outlet end of the fresh air blower to adjust the fluid flow rates at the inlet and outlet of the fresh air blower.The incineration boiler I3, incineration boiler II26, and mechanical grate 17 are installed at the bottom. A combined flue is installed at the top of the incineration boiler. The combined flue includes a vertical flue I9, a vertical flue II10, a vertical flue III11, and a horizontal flue 12 that are connected in sequence. An SNCR denitration device 40 is installed in the vertical flue I. The vertical flue I, vertical flue II, and vertical flue III form an S-shaped flue. An economizer 13 is installed at the end of the combined flue. The outlet of the economizer is connected to a tail gas treatment device. The tail gas treatment device includes a deacidification tower 4, a dust collector 5, an SGH steam heater 6, and an SCR flue gas denitration equipment 7 that are connected in sequence. The incineration boiler is equipped with a start-up blower I, a start-up blower II, an auxiliary combustion blower 15, and a cooling blower 16. Rubber expansion joints III are installed at the air inlet ends of the start-up blower I14, start-up blower II19, auxiliary combustion blower, and cooling blower. The incineration boiler I3, incineration boiler II26, and incineration boiler III32 are also connected to a secondary blower device. The secondary blower device includes a secondary blower 18. Rubber expansion joints II are installed on the air inlet and outlet pipelines of the secondary blower. The outlet of the secondary blower is connected to the incinerator through a primary air preheater.

[0028] The air and flue gas system of this waste incinerator has the following advantages compared with the original air and flue gas system:

[0029] 1. After the system is optimized, the odor overflow is reduced; when the boiler is started in the cold state, the inlet and outlet baffles of the primary blower are closed to prevent the odor from the garbage pit side from entering, and at the same time prevent the primary blower from rotating in reverse after the fresh air blower is started; after the induced draft fan is started, then start the fresh air blower. When the furnace temperature reaches 850 °C, the supply of primary air by the fresh air blower is switched to the operation of the primary blower; through system optimization, the grate bars can be synchronously cooled from room temperature to the hot state of the boiler, and the expansion is more uniform, solving the problem of the grate bars warping due to uneven expansion; during the process of the boiler heating up from normal temperature to 850 °C, air is provided by the fresh air blower, directly taking air from the atmosphere, and there is no odor problem; after the furnace temperature reaches 850 °C, it is switched to the operation of the primary blower to meet the negative pressure operation of the garbage pit, ensuring that the odor from the garbage pit can be completely burned after entering the furnace, and meeting the high-standard requirements for flue gas emissions;

[0030] 2. After the system is optimized, the maintenance of the furnace and the working environment of the boiler room are improved; every time the boiler needs to be shut down, before the garbage in the boiler is completely burned out, when the furnace temperature is guaranteed to be 850 °C and the auxiliary oil gun has been put into operation, the operation of the primary blower is switched to the operation of the fresh air blower to burn the odor in the furnace to the greatest extent, reducing the odor concentration in the furnace, facilitating the reduction of the odor during ventilation during shutdown maintenance, and improving the maintenance in the boiler and the working environment of the boiler room.

[0031] 3. After the system optimization, the reliability of the primary air system operation is improved, the boiler shutdown time due to faults is reduced, and the economic benefits are increased. When the boiler is operating normally, due to the reasons of the primary air fan itself, a serious fault occurs and it cannot be started in a short time. The fresh air fan can be used as the standby fan of the primary air fan, so that the boiler can continue to operate without shutdown while the faulty primary air fan is being repaired, and at the same time, the flue gas index can be ensured to be normal; environmental protection accidents can be avoided, the annual operating hours of the boiler are increased, the annual garbage treatment volume is increased, and finally the economic benefits of the company are improved.

[0032] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. One-pit-three-furnace urban domestic waste incinerator flue gas system, including a waste storage pit, Characterized in that: The waste storage pit is sequentially connected with a primary fan I, a primary air preheater I, and an incineration boiler I through pipeline I. The waste storage pit is also connected with a deodorization device I and a deodorization device II; the waste storage pit is sequentially connected with a primary fan II, a primary air preheater II, and an incineration boiler II through pipeline II; the waste storage pit is sequentially connected with a primary fan III, a primary air preheater III, and an incineration boiler III through pipeline III; the incineration boiler I, incineration boiler II, and incineration boiler III are connected with a tail gas treatment device, an induced draft fan, and a chimney; a fresh air fan device is also connected between pipeline I, pipeline II, and pipeline III. The fresh air fan device includes a fresh air fan. The air inlet end of the fresh air fan is communicated with the outside air through a fresh air inlet pipeline. A filter screen and a muffler are sequentially arranged on the fresh air inlet pipeline along the air flow direction. The air outlet end of the fresh air fan is respectively connected with the primary air preheater I, primary air preheater II, and primary air preheater III through a fresh air outlet pipeline I, fresh air outlet pipeline II, and fresh air outlet pipeline III. Outlet isolation baffles are movably arranged on the fresh air outlet pipeline I, fresh air outlet pipeline II, and fresh air outlet pipeline III; Mechanical grate and slag extractor are arranged at the bottom of the incineration boiler I, incineration boiler II, and incineration boiler III. The top of the incineration boiler I, incineration boiler II, and incineration boiler III is an outlet waste heat boiler. A combined flue is arranged in the outlet waste heat boiler. A economizer is arranged at the end of the outlet waste heat boiler. The outlet of the economizer is connected with the tail gas treatment device.

2. The one-pit-three-furnace urban domestic waste incinerator flue gas system according to claim 1, Characterized in that: The tail gas treatment device includes a deacidification tower, a dust collector, an SGH steam heater, and an SCR flue gas denitration reaction tower connected in sequence.

3. The one-pit-three-furnace urban domestic waste incinerator flue gas system according to claim 1, Characterized in that: Rubber expansion joints I are respectively arranged on the pipelines at the air inlet end and air outlet end of the fresh air fan.

4. The one-pit-three-furnace urban domestic waste incinerator flue gas system according to claim 1, Characterized in that: Electric regulating baffles are arranged at the air inlet end and air outlet end of the fresh air fan.

5. The one-pit-three-furnace urban domestic waste incinerator flue gas system according to claim 1, Characterized in that: The combined flue includes a vertical flue I, a vertical flue II, a vertical flue III, and a horizontal flue connected in sequence. The vertical flue I, vertical flue II, and vertical flue III form an S-shaped flue.

6. The one-pit-three-furnace urban domestic waste incinerator flue gas system according to claim 1, Characterized in that: The incineration boilers I, II, and III are also connected to a secondary fan device. The secondary fan device includes a secondary fan. Rubber expansion joints II are respectively arranged on the inlet and outlet pipelines of the secondary fan. The outlet of the secondary fan is connected to the incinerator through a primary air preheater.

7. According to the wind and smoke system of the one-pit-three-furnace urban domestic waste incinerator described in claim 1, It is characterized in that: The incineration boilers I, II, and III are equipped with an ignition fan I, an ignition fan II, an auxiliary combustion fan, and a cooling fan. Rubber expansion joints III are arranged at the inlet ends of the ignition fan I, ignition fan II, auxiliary combustion fan, and cooling fan.

8. According to the wind and smoke system of the one-pit-three-furnace urban domestic waste incinerator described in claim 1, It is characterized in that: The deodorization devices I and II each include a deodorization device inlet filter screen, a deodorization device inlet electric door, an activated carbon adsorption device, and an explosion-proof deodorization fan that are connected in sequence.

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