CN216047699U - Garbage incinerator primary air and flue gas hybrid system - Google Patents

Abstract

The utility model discloses a garbage incinerator primary air and flue gas mixing system, which comprises a garbage incinerator, a primary fan and a flue gas circulating fan, wherein the primary fan is connected with a garbage incinerator pipeline, the flue gas circulating fan is respectively connected with a flue gas outlet of the garbage incinerator and a primary air chamber pipeline, and low-oxygen flue gas is pumped into a primary air chamber to replace part of primary air, so that the primary air consumption can be effectively reduced, the excessive air coefficient of the incinerator is reduced, the temperature distribution in the incinerator is improved, NOx is reduced from the source, and the pressure of tail flue gas denitration treatment is reduced; meanwhile, the consumption of the primary air is reduced, the steam consumption required by heating the primary air is also reduced, the heat efficiency is effectively improved, and the method has better economic and environmental benefits.

Description

Garbage incinerator primary air and flue gas hybrid system

Technical Field

The utility model relates to the technical field of combustion control of a mechanical grate furnace of a garbage incinerator, in particular to a primary air and flue gas mixing system of the garbage incinerator.

Background

Along with the further acceleration of the urbanization process, the quantity of municipal solid waste is increased rapidly, and the municipal solid waste incineration treatment technology is more and more favored by many cities at home and abroad due to the advantages of good harmless effect, high reduction degree, good resource utilization effect and the like.

The main equipment of the waste incineration treatment system is a waste incineration grate furnace, various grate incinerators have different shapes due to different grate structures and movement modes, but the basic combustion principles are approximately the same, the waste is subjected to layered combustion on the grate, and ash residues are discharged out of the furnace after drying, combustion and burning. The waste incineration grate furnace is divided into a drying section, a combustion section and a burning-out section according to different functions, a primary air chamber is arranged below each grate area, and air is supplied in a segmented mode through the primary air chambers. The garbage incinerator is generally provided with primary air and secondary air, wherein the primary air is a primary air chamber at the bottom of a grate and is sent into the incinerator for volatilizing moisture in garbage; the secondary air is pressurized by a secondary fan and then sent into the hearth, so that the flue gas of the hearth generates strong turbulence to disturb airflow to ensure that the combustion is safer, the contact of combustible substances and oxygen is promoted, the heat loss of chemical incomplete combustion is eliminated, and the burning-out of carbon particles in fly ash is facilitated.

The garbage enters an incinerator grate, is firstly dried by primary air in a drying section, part of water is volatilized, then enters a combustion section for combustion, in order to ensure that fuel is fully combusted, air with an excess coefficient of 1.8-2.0 is generally introduced into the incinerator in the combustion process, and finally ash residues are discharged out of the incinerator. In the treatment process, primary air in the drying section is ambient air, the primary air is heated to the air temperature (160-220 ℃) required by the primary air by an air preheater, the primary air does not participate in combustion, but the ambient air contains a large amount of oxygen, and excessive oxygen and volatile nitrogen and coke nitrogen in the combustion section are subjected to oxidation reaction in a high-temperature section of a hearth to generate a large amount of NOx.

With the increasing environmental pollution and the increasing shortage of energy sources, people hope to realize energy conservation and emission reduction through a novel combustion mode, wherein the flue gas recirculation technology refers to a combustion mode that partial flue gas generated by combustion is mixed with an oxidant and then participates in the combustion process again, has the advantages of reducing NOx emission and improving combustion efficiency, and is widely applied to the fields of industrial combustors, boilers, gas turbines, internal combustion engines, Stirling engines and the like. In a waste incinerator, the conventional flue gas recirculation adopts flue gas to replace secondary air, but the fluctuation of waste components is large, so that the combustion working condition has large fluctuation, and after the low-oxygen flue gas is adopted to replace the secondary air, the low-oxygen flue gas is difficult to burn out incompletely combusted fly ash carbon particles in the continuous fluctuation process of the working condition, so that the condition that CO exceeds the standard easily occurs.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical defects, the utility model provides a mixed combustion system of air and flue gas of a garbage incinerator, which replaces part of primary air with the flue gas to adjust the oxygen content of a combustion section, so that not only can the fuel be fully combusted, but also the generation amount of NOx is relatively low, and meanwhile, the consumption amount of the primary air can be effectively reduced.

The utility model is realized by the following technical scheme:

a primary air and flue gas mixing system of a garbage incinerator comprises the garbage incinerator, a primary fan and a flue gas circulating fan, wherein the garbage incinerator comprises a mechanical grate and a plurality of primary air chambers, the mechanical grate is divided into a drying section, a combustion section and a burning section, and the bottom of each grate section is provided with a corresponding primary air chamber; the primary air fans are respectively connected with the primary air chamber pipelines; one end of the smoke circulating fan is communicated with a smoke outlet of the garbage incinerator or a smoke pipeline between the subsequent adjacent sections of the garbage incinerator, and the other end of the smoke circulating fan is connected with a primary air chamber pipeline of the drying section and/or the combustion section so as to pump smoke into the corresponding primary air chamber to replace part of primary air.

Compared with the prior art, the utility model has the following beneficial effects:

according to the utility model, a part of flue gas is extracted from a flue gas outlet of the garbage incinerator through a flue gas circulating fan, is conveyed into a primary air chamber, is mixed with primary air, and then is conveyed into the primary air chamber of a mechanical grate drying section, so that the waste heat of high-temperature flue gas is utilized to heat and dry materials which just enter the mechanical grate drying section; one part of the waste is sent into a primary air chamber of a combustion section of the mechanical grate to be mixed with primary air, so that the waste is ensured to be fully combusted. The treatment process can effectively reduce the consumption of primary air, reduce the excess air coefficient in the incinerator, improve the temperature distribution in the incinerator, reduce the generation amount of NOx from the source and reduce the pressure of tail flue gas denitration treatment; moreover, because the consumption of primary air is reduced, the steam consumption required by heating the primary air is also reduced, and the heat efficiency of the whole plant is effectively improved; meanwhile, the circulating flue gas is recycled in the system, so that the amount of the flue gas directly discharged into the atmospheric environment is effectively reduced, and pollutants discharged into the atmosphere are reduced; has great economic and environmental benefits.

Furthermore, air door baffles are arranged in a pipeline between one end of the flue gas circulating fan and the flue gas outlet or the flue gas pipeline and a pipeline of the primary air chamber of the drying section and/or the combustion section, and are used for adjusting the air volume of the flue gas. The garbage incinerator has larger fluctuation of the combustion working condition due to larger fluctuation of garbage components, and the air quantity of the flue gas recirculation is adjusted through the air door baffle under the condition that the fuel component changes greatly, so that the garbage incinerator is better adapted to the combustion working condition.

Furthermore, the garbage incinerator also comprises a feeding grate and a hearth, wherein the feeding grate is arranged on the outer side of the drying section of the mechanical grate, and an outlet of the feeding grate is tightly connected with the outer side of the drying section; the furnace chamber is arranged above the mechanical grate, and the inlet of the furnace chamber covers all grate sections, so that the flue gas generated by the grate sections completely enters the furnace chamber.

Furthermore, the follow-up working sections of the garbage incinerator comprise a waste heat boiler, a deacidification reaction tower, a bag-type dust remover and an induced draft fan, wherein the waste heat boiler is communicated with the smoke outlet of the hearth, and the working sections are communicated through smoke pipelines.

Further, the system also comprises a secondary air fan which is communicated with the hearth pipeline, so that secondary air is conveyed into the hearth, the flue gas of the hearth generates strong turbulence, the combustion of combustible is accelerated, and the chemical incomplete combustion loss is eliminated.

Furthermore, the flue gas circulating fan adopts a variable frequency circulating fan or a power frequency circulating fan.

Furthermore, the air door baffle plate is selected from a manual air door baffle plate, an electric air door baffle plate or a pneumatic air door baffle plate.

Drawings

FIG. 1 is a schematic diagram of the flue gas recirculation of the present invention.

Wherein, 1-a garbage incinerator; 2-a waste heat boiler; 3-deacidifying reaction tower; 4-bag dust collector; 5-a draught fan; 6-primary air blower; 7-a secondary air fan; 8-a flue gas circulating fan; 9-an air preheater; 10-damper flap; 11-a mechanical grate; 12-a feed grate; 13-a hearth; 14-a grate drying section air chamber; 15-a grate combustion section air chamber; 16-a furnace grate burnout section air chamber.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the specification, but the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and the scope of the present invention is not limited thereto.

Referring to fig. 1, in the prior art, a waste incineration system generally includes a plurality of devices, such as a waste incinerator 1, a waste heat boiler 2, a deacidification reaction tower 3, a bag-type dust collector 4, a primary air fan 6, a secondary air fan 7, an induced draft fan 5, and the like; the garbage incinerator 1 is a key device of the garbage incineration processing system, it includes feeding grate 12, mechanical grate 11 and burner hearth 13, wherein the mechanical grate 11 is divided into grate drying section, grate burning section according to the function difference, there are primary wind chambers in each grate section inferior part, namely grate drying section wind chamber 14, grate burning section wind chamber 15 and grate burning section wind chamber 16, the primary air blower is supplied air sectionally through the wind chamber, the primary air blower 6 is installed near every primary wind chamber, the pipeline is connected to every primary wind chamber, send into the primary air chamber to every primary wind chamber, the primary air that sends into the primary wind chamber is hot-blast generally, and the primary air is taken from the ambient wind, so mount the primary air preheater 9 on the pipeline between primary air blower 6 and primary wind chamber, heat the primary air to the necessary inlet wind temperature; the secondary air fan 7 is arranged near the hearth 13 and is communicated with the hearth 13 through a pipeline, and secondary air is pressurized by the secondary air fan 7 and then is sent to the upper part of the hearth 13, so that flue gas in the hearth 13 generates strong turbulence, the contact of combustible materials and oxygen is promoted, and the heat loss of chemical incomplete combustion is eliminated; the waste heat boiler 2 is arranged at a flue gas outlet of the hearth 13, the deacidification reaction tower 3 and the bag-type dust collector 4 are sequentially arranged behind the waste heat boiler 2, and all devices are communicated by flue gas pipelines to treat flue gas; the draught fan 5 is connected to the bag-type dust collector 4 through a pipeline and used for extracting smoke to a chimney for discharging.

The primary air and flue gas mixing system of the garbage incinerator is arranged in the garbage incineration treatment system to treat flue gas discharged from a hearth 13, the treatment process is mainly completed by a flue gas circulating fan 8, one end of the flue gas circulating fan 8 is communicated with a flue gas pipeline between a bag-type dust collector 4 and an induced draft fan 5, and the other end of the flue gas circulating fan is connected with one or more primary air chamber pipelines, so that part of the flue gas is pumped into the corresponding primary air chamber and mixed with primary air to enter the hearth 13, and the cyclic utilization of the flue gas is completed.

The flue gas circulating fan 8 is connected with the primary air chamber, and one end of the flue gas circulating fan is provided with two branch pipes which are respectively connected to the grate drying section air chamber 14 and the grate combustion section air chamber 15, in the grate drying section air chamber 14, the waste heat of high-temperature flue gas is fully utilized to dry the garbage which just enters the grate drying section, and meanwhile, the total amount of primary air can be reduced, and the steam consumption of the primary air heated by the air preheater is reduced; in the grate combustion section air chamber 15, flue gas and primary air are mixed and then enter the hearth 13, the oxygen content of the grate combustion section is adjusted, the fuel is ensured to be fully combusted, excessive oxygen in the hearth 13 is reduced, the generation of NOx is reduced, and the operation and maintenance cost of a subsequent denitration system is reduced.

In one embodiment, the flue gas circulating fan 8 is connected with a flue gas outlet pipeline of the waste heat boiler 4 to extract flue gas in the garbage incinerator 1. In other embodiments, the flue gas circulating fan 8 may be connected to the flue gas pipeline between the exhaust-heat boiler 2 and the denitration reaction tower 3, or connected to the flue gas pipeline between the denitration reaction tower 3 and the bag-type dust collector 4 or the flue gas pipeline behind the induced draft fan 5.

In one embodiment, an air door baffle plate 10 is arranged in a pipeline connecting the flue gas circulating fan 8 with the grate drying section air chamber 14 or the grate combustion section air chamber 15 and a pipeline for flue gas entering the flue gas circulating fan 8, and the air quantity of flue gas recirculation is adjusted according to the combustion working condition, so that the heat efficiency is improved.

In one embodiment, the damper 10 is a shut-off damper or a regulating damper, or a manual damper, an electric damper or a pneumatic damper according to the driving method.

In one embodiment, the flue gas recirculation fan 8 is a variable frequency recirculation fan or a power frequency recirculation fan.

The working principle of the utility model is as follows: according to the combustion principle of the garbage incinerator and the subsection of the grate function, the grate drying section which needs less oxygen is dried by using the waste heat of the flue gas; the oxygen content of the air in the combustion section is adjusted by using the low-oxygen flue gas in the combustion section of the grate, the steam required for heating the air is effectively reduced, and meanwhile, the low-oxygen flue gas replaces part of primary air, so that the oxygen content of the combustion section of the grate is reduced, the generation of NOx is reduced, the heat utilization efficiency is improved, and the aims of reducing pollutant emission and saving energy are fulfilled.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The present invention is not limited to the above-described embodiments, and various changes and modifications of the present invention are intended to be included within the scope of the claims and the equivalent technology of the present invention if they do not depart from the spirit and scope of the present invention.

Claims (7)

1. A primary air and flue gas mixing system of a garbage incinerator is characterized by comprising the garbage incinerator, a primary fan and a flue gas circulating fan, wherein the garbage incinerator comprises a mechanical grate and a plurality of primary air chambers, the mechanical grate is divided into a drying section, a combustion section and a burning section, and the bottom of each grate section is provided with a corresponding primary air chamber; the primary air fans are respectively connected with the primary air chamber pipelines; one end of the smoke circulating fan is communicated with a smoke outlet of the garbage incinerator or a smoke pipeline between the subsequent adjacent sections of the garbage incinerator, and the other end of the smoke circulating fan is connected with a primary air chamber pipeline of the drying section and/or the combustion section so as to pump smoke into the corresponding primary air chamber to replace part of primary air.

2. The garbage incinerator primary air and flue gas mixing system as claimed in claim 1, wherein air door baffles are arranged in the pipeline between one end of the flue gas circulating fan and the flue gas outlet or flue gas pipeline and in the pipeline between one end of the flue gas circulating fan and the primary air chamber of the drying section and/or the combustion section for adjusting the air volume of the flue gas.

3. The primary air and flue gas mixing system of the garbage incinerator according to claim 1, wherein the garbage incinerator further comprises a feeding grate and a hearth, the feeding grate is arranged outside the drying section of the mechanical grate, and the outlet of the feeding grate is tightly connected with the outside of the drying section; the furnace chamber is arranged above the mechanical grate, and the inlet of the furnace chamber covers all grate sections.

4. The primary air and flue gas mixing system of the garbage incinerator according to claim 3, wherein the subsequent sections of the garbage incinerator comprise a waste heat boiler, a deacidification reaction tower, a bag-type dust collector and an induced draft fan, the waste heat boiler is communicated with the flue gas outlet of the hearth, and the sections are communicated with each other through flue gas pipelines.

5. The waste incinerator primary air and flue gas mixing system of claim 3, further comprising a secondary air fan, said secondary air fan being in communication with said furnace duct.

6. The garbage incinerator primary air and flue gas mixing system as claimed in claim 1, wherein said flue gas circulating fan is a variable frequency circulating fan or a power frequency circulating fan.

7. The primary air and flue gas mixing system of the garbage incinerator according to claim 2, wherein said damper baffle is selected from a manual damper baffle, an electric damper baffle or a pneumatic damper baffle.

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