1. The utility model provides a two furnace waste incineration device of large capacity high load, includes primary air system (100), overgrate air system (200), charge-in system (300), furnace (400), flue (500) and lime-ash export (600), its characterized in that: the garbage incineration device is symmetrically arranged in the depth direction of a hearth (400) and is of a double-hearth structure, two combustion centers which are symmetrically distributed are formed on a grate at the bottom of the hearth (400), the left side and the right side of the hearth (400) are respectively connected with a front wall (301) and a rear wall (302) of a feeding system (300), the top of the hearth (400) is connected with a flue (500) through a flue inlet (501), the bottom of the hearth (400) is connected with an ash outlet (600), a primary air system (100) is connected with the bottom of the hearth (400), a secondary air system (200) is connected with the top of the hearth (400), and the hearth (400) comprises an arch wall, a side wall (402), a drying grate (410) and a burn-out grate (420); the arch wall is arranged at the upper part of the hearth (400), the side walls (402) are arranged at the left side and the right side of the hearth (400), and the drying grate (410) and the burn-out grate (420) are arranged at the bottom of the hearth (400) to jointly form a combustion space of the hearth (400).

2. A large capacity high load double hearth waste incineration apparatus as claimed in claim 1, wherein said hearth (400) is surrounded by the drying grate (410), the burn-out grate (420), the ash inlet (601) of the ash outlet (600), the side wall (402), the arch wall and the flue inlet (501), and arranged symmetrically, the hearth (400), the flue (500) and the ash outlet (600) are arranged coaxially, the drying grate (410) and the burn-out grate (420) are arranged symmetrically at two sides of the bottom of the hearth (400), and said drying grate (410) is arranged at the upper part of the burn-out grate (420) and connected obliquely.

3. A large capacity high load double hearth refuse incineration plant according to claim 1, characterised in that said arch walls comprise a front arch wall (4011) and a rear arch wall (4012) which reflect the heat released by refuse combustion directly in the form of radiation to the bed of the lower grate, the front arch wall (4011) being located above the drying section (4101) and the burn-out section (4201) adjacent to the front wall (301); the rear arch wall (4012) is located above the drying section (4102) and the burning ember section (4202) close to the rear wall (302).

4. A large capacity high load double hearth refuse incineration plant according to claim 1, characterised in that said primary air system (100) is provided with a primary air inlet one (411) connected to the drying grate (410), the primary air system (100) is provided with a primary air inlet two (421) connected to the burn-out grate (420), the primary air system (100) is provided with a primary air inlet three (602) connected to the ash outlet (600); the primary air inlet I (411), the primary air inlet II (421) and the primary air inlet III (602) respectively pass through different oxidants.

5. A large-capacity high-load double-hearth waste incineration device as claimed in claim 4, characterized in that the oxidant passing through the first primary air inlet (411) is a mixed gas of high-temperature circulating flue gas and high-temperature preheated air, the temperature range of the mixed gas is 350 ℃ -650 ℃, the air rate is 25% -35%, the concentration of oxygen in the mixed gas is 10% -15%, and the source of the mixed gas is flue gas in a high-temperature flue and high-temperature air at the outlet of an air preheater; the oxidant passing through the second primary air inlet (421) is an oxygen-enriched oxidant, and the sources of the oxidant are high-temperature air and high-concentration oxygen at the outlet of the air preheater, wherein the concentration of the oxygen is 25-35%, the air rate is 55-65%, and the temperature range is 150-350 ℃; the oxidant passing through the primary air inlet III (603) is primary preheated air which comes from the outlet of the air preheater, the air rate is 5-10%, and the temperature range is 150-250 ℃.

6. A large capacity high load double hearth waste incineration apparatus as set forth in claim 1, wherein the overfire air blow-out ports (201) of said overfire air system (200) are located at the outlet of the hearth (400), the overfire air blow-out ports (201) are arranged in a multi-layer structure, and the overfire air blow-out ports (202) of the bottom layer are arranged on the arch wall; the secondary air nozzles II (202) outside the bottom layer are uniformly arranged on the vertical flue (500), and the number of the secondary air nozzles II (202) arranged on the flue (500) is not less than 3.

7. A large capacity high load double hearth waste incineration plant as claimed in claim 1, characterised in that said flue (500) is located directly above the fire grate of the combustion section, its vertical projection will cover the whole dry pyrolysis grate and part of the burn-out grate, and the vertical projection coverage area is not larger than 1/4 area of the burn-out grate (420).

8. A large capacity high load double hearth refuse burning installation according to claim 1, wherein said ash outlet (600) is a throat structure (603), and a primary air nozzle (611) and a baffle structure (610) are provided on the throat structure (603).

9. A large capacity high load double hearth refuse incineration plant according to claim 1, characterised in that the arch wall, the side walls (402) and the flue (500) are constructed in the form of water cooled walls.

10. The large-capacity high-load double-hearth waste incineration device as claimed in claim 1, wherein the temperature of the flue gas above the drying grate (410) is 900-1100 ℃, the temperature of the flue gas above the burn-out grate (420) is 1200-1400 ℃, and the temperature of the flue gas at the ash outlet (600) is 250-350 ℃.

Background

The waste incineration power generation technology can realize reduction, harmlessness and reclamation of the waste. With the continuous development of the technology, people pay attention to the waste incineration technology in three aspects of waste treatment capacity, energy recovery rate and pollutant emission. The optimization improvement of the three aspects is based on good hearth structure and optimized combustion control strategy. At present, the treatment capacity of waste incineration reaches the scale of 1000t/D, and the width of the incinerator reaches 12 m. The continuous increase of the width of the hearth to improve the garbage treatment capacity has difficulty in the structural design of a single hearth and the arrangement of subsequent heating surfaces. The increase of the width of the hearth does not obviously improve the heat load of unit volume in the hearth, does not bring about the increase of characteristic values such as main steam parameters of a unit, and can not improve the heat efficiency of the unit and the heat exchange efficiency in the hearth. And the diversity characteristic of the rubbish in the aspect of composition and calorific value is obvious, and the increase of furnace width can aggravate the hot deviation of flue gas and heated surface in the furnace.

Therefore, designing an incineration device with large capacity and high load has important propulsion function for garbage treatment and energy recovery.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the utility model provides a two furnace waste incineration grate boilers of large capacity high load, improves the burning velocity of waste fuel in the furnace and the heat load in the unit volume through brand-new furnace structure and the burning organization mode in order to realize the purpose of large capacity high load.

In order to solve the technical problems, the technical scheme of the invention is to provide a large-capacity high-load double-hearth waste incineration device, which comprises a primary air system, a secondary air system, a feeding system, a hearth, a flue and an ash residue outlet, and is characterized in that: the garbage incineration device is symmetrically arranged in the depth direction of the hearth and is of a double-hearth structure, two combustion centers which are symmetrically distributed are formed on a grate at the bottom of the hearth, the left side and the right side of the hearth are respectively connected with a front wall and a rear wall of a feeding system, the top of the hearth is connected with a flue through a flue inlet, the bottom of the hearth is connected with an ash outlet, a primary air system is connected with the bottom of the hearth, a secondary air system is connected with the top of the hearth, and the hearth comprises an arch wall, a side wall, a drying grate and an exhaust combustion grate; the arch wall is arranged on the upper part of the hearth, the side walls are arranged on the left side and the right side of the hearth, and the drying grate and the burn-out grate are arranged at the bottom of the hearth to jointly form a combustion space of the hearth.

Preferably, the hearth is surrounded by a drying grate, a burn-out grate, an ash inlet of an ash outlet, a side wall, an arch wall and a flue inlet, and is symmetrically arranged, the hearth, the flue and the ash outlet are coaxially arranged, the drying grate and the burn-out grate are symmetrically arranged at two sides of the bottom of the hearth, and the drying grate is arranged at the upper part of the burn-out grate and is obliquely connected with the burn-out grate; the drying grate and the burn-out grate respectively correspond to two independent processes of pyrolysis and combustion reaction of the garbage in the material layer.

Preferably, the arch walls comprise a front arch wall and a rear arch wall which can directly reflect heat released by garbage combustion to a material layer of the lower grate in a radiation mode, and the front arch wall is positioned above the drying section and the combustion burning-out section which are close to the front wall; the rear arch wall is positioned above the drying section and the burning and burning-out section which are close to the rear wall.

Preferably, the primary air system is provided with a primary air inlet I connected with the drying grate, the primary air system is provided with a primary air inlet II connected with the burn-out grate, and the primary air system is provided with a primary air inlet III connected with the ash outlet; the primary air inlet I, the primary air inlet II and the primary air inlet III respectively pass through different oxidants.

Preferably, the oxidant passing through the first primary air inlet is a mixed gas of high-temperature circulating flue gas and high-temperature preheated air, the temperature range of the mixed gas is 350-650 ℃, the air rate is 25-35%, the concentration of oxygen in the mixed gas is 10-15%, and the source of the mixed gas is flue gas in a high-temperature flue and high-temperature air at the outlet of an air preheater; the oxidant passing through the primary air inlet II is an oxygen-enriched oxidant, and the sources of the oxidant are high-temperature air at the outlet of the air preheater and high-concentration oxygen, wherein the concentration of the oxygen is 25-35%, the air rate is 55-65%, and the temperature range is 150-350 ℃; the oxidant passing through the primary air inlet III is primary preheated air which comes from the outlet of the air preheater, the air rate is 5-10%, and the temperature range is 150-250 ℃.

Preferably, the secondary air nozzles of the secondary air system are positioned at the outlet of the hearth, the primary air nozzles are arranged in a multilayer structure, and the secondary air nozzles at the bottom layer are arranged on the arch wall; and the secondary air nozzles II outside the bottom layer are uniformly arranged on the vertical flue, and the number of the secondary air nozzles II arranged on the flue is not less than 3.

Preferably, the flue is positioned right above the combustion section grate, the vertical projection of the flue covers the whole dry pyrolysis grate and part of the burn-out grate, and the vertical projection covers the area which is not larger than 1/4 of the burn-out grate.

Preferably, the ash outlet is a throat structure, and a primary air nozzle and a baffle structure are arranged on the throat structure.

Preferably, the arch wall, the side wall and the flue all adopt a water-cooled wall structure, no air-cooled wall is arranged, and the fire facing surface of the arch wall, the side wall and the flue is laid by SiC type refractory materials.

Preferably, the temperature of the flue gas above the drying grate is 900-1100 ℃, the temperature of the flue gas above the burning-out grate is 1200-1400 ℃, and the temperature of the flue gas at the ash residue outlet is 250-350 ℃.

Preferably, the flue is surrounded by membrane water-cooled walls, the fire side is laid by SiC type refractory materials, and the flue is connected with water-cooled wall outlets of the arch wall and the side wall in a header mode.

Preferably, the secondary air enters the hearth through secondary air nozzles, and the secondary air nozzles are arranged in a plurality of rows along the width direction of the hearth and are sourced from conventional air.

Preferably, the CaO powder enters through a secondary air nozzle arranged on the arch wall, enters the hearth under the wrapping of gravity and fluid, and reacts with the acid gas in the flue gas.

Preferably, the source of the high-temperature flue gas selects the position of a flue without a heating surface, and the selected circulating flue gas fan adopts a variable frequency design to adjust the flow and the speed of the circulating flue gas.

The invention has the characteristics that:

1. the double-hearth waste incineration boiler with large capacity and high load has the advantages of large waste treatment capacity, high unit heat load and flue gas temperature of the hearths, high system heat efficiency and capability of effectively reducing the emission of pollutants such as dioxin. The improvement of the unit heat load of the hearth makes the structure of the hearth more compact, and provides possibility for adopting high parameters for a subsequent evaporation system.

2. Compared with the existing combustion structure with a single hearth, the flow field and the temperature field which are symmetrically arranged in the double hearths are more uniformly distributed, and particularly the flow field and the temperature field in the outlet flue are more uniform.

3. The fire grate is divided into two parts of drying and burning embers, independent control strategies are adopted respectively, different oxidant combinations are adopted in different stages, the temperature and the flow of the oxidant are adjusted according to the heat value of the fuel, the parameters of entering high-temperature flue gas are effectively adjusted and controlled, and the adaptability of the unit to load change, unstable burning and fuel diversity is improved.

4. The ash outlet design can well ensure and maintain the negative pressure in the hearth, and the problem of large fluctuation of the pressure in the hearth caused by the discharge of the slag is reduced.

Drawings

FIG. 1 is a schematic view of a large capacity high load double hearth waste incineration plant;

FIG. 2 is a schematic top view of a furnace;

FIG. 3 is a schematic diagram of the arrangement of secondary air nozzles;

fig. 4 is a schematic view of the ash outlet.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.

As shown in fig. 1 to 4, the garbage incineration device with large capacity and high load comprises a primary air system 100, a secondary air system 200, a feeding system 300, a hearth 400, a flue 500 and an ash outlet 600, wherein the garbage incineration device is symmetrically arranged along the depth direction of the hearth 400 and has a double-hearth structure, and two combustion centers are symmetrically distributed on a grate at the bottom of the hearth 400. The left side and the right side of a hearth 400 are respectively connected with a front wall 301 and a rear wall 302 of a feeding system 300 up and down, the top of the hearth 400 is connected with a flue 500 through a flue inlet 501, the bottom of the hearth 400 is connected with an ash outlet 600, a primary air system 100 is connected with the bottom of the hearth 400, a secondary air system 200 is connected with the top of the hearth 400, and the hearth 400 comprises an arch wall, a side wall 402, a drying grate 410 and an exhaust combustion grate 420; the arch wall is arranged at the upper part of the hearth 400, the side walls 402 are arranged at the left side and the right side of the hearth 400, the drying grate 410 and the burn-out grate 420 are arranged at the bottom of the hearth 400 to jointly form a combustion space of the hearth, the hearth 400 is surrounded by the drying grate 410, the burn-out grate 420, an ash inlet 601 of the ash outlet 600, the side walls 402, the arch wall and a flue inlet 501 and is symmetrically arranged, the hearth 400, the flue 500 and the ash outlet 600 are coaxially arranged, the drying grate 410 and the burn-out grate 420 are symmetrically arranged at the two sides of the bottom of the hearth 400, the drying grate 410 is arranged at the upper part of the burn-out grate 420 and is obliquely connected with the drying grate 410 and the burn-out grate 420, the arch wall comprises a front arch wall 4011 and a rear arch wall 4012, the front arch wall 4011 is positioned above a drying section 4101 and a burn-out section 4201 which are close to the front wall 301, the heat released by the combustion of the garbage can be directly reflected to the material layer of the lower grate in a radiation mode; the rear arch wall 4012 is positioned above the drying section 4102 and the burning and burning section 4202 close to the rear wall 302, and can directly reflect heat released by burning garbage to a material layer of a grate below, the range of the included angle alpha is 15-35 degrees, the primary air system 100 is provided with a primary air inlet I411 connected with the drying grate 410, the primary air system 100 is provided with a primary air inlet II 421 connected with the burning and burning grate 420, and the primary air system 100 is provided with a primary air inlet III 602 connected with the ash residue outlet 600; the primary air system 100 adopts different control strategies for different air inlets, uses oxidants with different parameters, the oxidant passing through the primary air inlet I411 is a mixed gas of high-temperature circulating flue gas and high-temperature preheated air, the temperature range of the mixed gas is 350-650 ℃, the air rate is 25-35%, the concentration of oxygen in the mixed gas is 10-15%, and the source of the mixed gas is flue gas in a high-temperature flue and high-temperature air at the outlet of an air preheater; the oxidant passing through the second primary air inlet 421 is an oxygen-enriched oxidant 101, the sources are high-temperature air at the outlet of the air preheater and high-concentration oxygen, the concentration of the oxygen in the mixed gas is 25% -35%, the air rate is 55% -65%, and the temperature range is 150 ℃ -350 ℃; the oxidant passing through the primary air inlet III 603 is conventional primary preheated air and comes from the outlet of the air preheater, the air rate is 5% -10%, the temperature range is 150 ℃ -250 ℃, the secondary air nozzle I201 of the secondary air system 200 is positioned at the outlet of the hearth 400 and is arranged in multiple layers, the secondary air nozzle II 202 arranged at the bottom layer is arranged on the arch wall and used for adjusting the temperature and components of flue gas in the hearth 400 and preventing the problems of high-temperature coking and the like, other layers are arranged on the vertical flue, and the number of the arranged secondary air nozzle II 202 is not less than 3. The flue 500 comprises a flue inlet 501, a flue water wall 502 and a flue outlet 503, the flue 500 is positioned right above the fire grate of the combustion section, the projection in the vertical direction of the flue 500 can cover part of the burn-off grate 420, the vertical projection coverage area is not more than the 1/4 area of the burn-off grate 420, the ash outlet 600 adopts a throat structure 603, a primary air nozzle 611 and a baffle structure 610 are arranged on the throat structure 603, and the inclination angle beta of the throat structure 603 ranges from 30 degrees to 50 degrees.

The invention relates to a large-capacity high-load double-hearth waste incineration boiler which comprises a primary air system 100, a secondary air system 200, a fuel feeding system 300, a hearth 400, a segmented incinerator grate, a flue 500 and an ash outlet 600. The household garbage enters the hearth 400 through the feeding system 300, the garbage is dried and pyrolyzed through the pusher and the drying grate 410 of the grate, and along with the completion of pyrolysis, the garbage enters the combustion exhaust grate 420 for combustion reaction until the combustion process is finished and enters the ash inlet 601 under the operation of the grate. The flue gas generated after the garbage is combusted enters the flue 500 at the outlet of the hearth 400 upwards along the structure of the hearth 400 and is exhausted from the flue outlet 503. The hearth 400 and the flue 500 are surrounded by a water-cooled wall structure, the inlet 501 of the flue is connected with the outlet of the hearth 400, and the inner wall of the flue is coated with refractory materials to ensure the safety of the water-cooled wall.

The whole combustion process is divided into two independent processes of drying pyrolysis and combustion burnout, and different oxidants and control strategies are adopted respectively. The primary air system 100 is connected with the primary air mixer I103 and the primary air mixer II 104, and oxidants required in the combustion process respectively enter different fire grates through primary air inlets arranged on the slag leakage hopper. Wherein, in order to improve the garbage drying process of the drying grate 410, the drying grate 410 adopts the combined action of high-temperature circulating flue gas convection and arch wall radiation heat exchange. High temperature flue gas recirculation can also improve CO in the furnace 400₂The concentration of the nitrogen oxides in the hearth 400 is adjusted, the staged combustion is realized, and the generation amount of the nitrogen oxides is reduced. The source of the oxidant in the drying section is a mixed gas of high-temperature circulating flue gas and primary air from an air preheater, the concentration of oxygen in the mixed gas is 10-15%, and the range of the high-temperature flue gas is 450-650 ℃. The main combustion process occurs in the combustion and burnout section, the oxidant passing through the second primary air inlet 421 is the oxygen-enriched oxidant 101, the concentration of oxygen in the mixed gas is 25% -35%, and the temperature range is 150 ℃ -350 ℃. The increase of the oxygen concentration can obviously enhance the combustion intensity and improve the combustion temperature and the heat load in the hearth. The increase in oxygen concentration also significantly reduces the combustion time and increases the waste throughput. The burned garbage enters the ash outlet 600 under the action of the fire grate, and the discharge amount of the ash is controlled by the baffle structure 610. Through the primary air inlet III602, the flow of ash can be improved, and the distribution of the flow field and the temperature field of the flue gas in the center of the hearth 400 can be adjusted. The baffle structure 610 can effectively improve the sealing performance of the hearth 400, reduce the strong impact of a large amount of steam generated after ash enters the slag pusher on the pressure and the smoke components of the hearth 400, and solve the problem of large pressure fluctuation in the hearth 400. Meanwhile, the increase of the oxygen concentration in the primary air of the drying grate 410 can strengthen the combustion process, improve the temperature of the combustion center, reduce hydrocarbon (CmHn) generated due to insufficient oxygen, insufficient mixing or low temperature and the like, completely decompose the hydrocarbon into carbon dioxide and water, and reduce the formation of dioxin or a precursor thereof by combining the carbon dioxide and chloride in garbage, so as to realize the purpose of controlling the generation of the dioxin in the combustion process.

Besides, the combustion temperature of the center of the hearth is controlled by using the high-temperature circulating flue gas and the oxygen concentration, the radiant heat exchange is enhanced through the arch wall, the drying and combustion processes of the fuel are enhanced, and the burnout rate is improved.

The secondary air system 200 is connected with a secondary air box 204, CaO powder 203 enters a hearth 400 through a primary secondary air nozzle 201 and a secondary air nozzle 202 arranged at the bottom layer of the arch wall, enters the hearth area of the hearth 400, forms a W-shaped motion track, and enters a subsequent flow from an outlet of a flue 500. The addition of the CaO powder 203 can control the content of acid gas in the flue gas in the combustion process, and prevent the water-cooled wall and the subsequent high-temperature heating surface from being corroded by the acid gas. The method provides possibility for subsequently arranging high-temperature heating surfaces such as a superheater and a reheater and improving steam parameters of the system.

The fan used by the circulating flue gas system 102 is designed in a variable frequency manner, and the flow and speed of the circulating flue gas can be adjusted.