Denitration device for waste incineration

Abstract

The utility model provides a denitration device for waste incineration, and relates to the technical field of solid waste treatment. The denitration device for waste incineration comprises a smoke exhaust pipeline and a denitration device, wherein one end of the smoke exhaust pipeline is communicated with the upper part of an incineration boiler; the spraying system comprises a storage container arranged outside the smoke exhaust pipeline, the storage container is communicated with a spraying pump, the spraying pump is communicated with a spraying assembly, and the spraying assembly is arranged on the smoke exhaust pipeline in a penetrating mode; the backflow system comprises a backflow pump arranged outside the smoke exhaust pipeline; the air inlet end of the backflow system communicates with the smoke exhaust pipeline, and the air outlet end of the backflow system communicates with the incineration boiler. Wherein the communicating position of the backflow system and the smoke exhaust pipeline is arranged on the pipe section, behind the injection assembly, of the smoke exhaust pipeline, so that the backflow system can input combusted and denitrated gas into the incineration boiler; according to the utility model, the nitrogen oxide content of the discharged flue gas can be effectively reduced, the use amount of denitration raw materials can be reduced, and the corrosion of the water-cooled wall is slowed down.

Description

TECHNICAL FIELD

[0001] The utility model relates to solid waste treatment technical field, concretely is a kind of denitration device for garbage incineration. BACKGROUND

[0002] Pollutant emission of garbage incineration plant in solid waste treatment technical field has been paid great attention to, and higher requirements are proposed for the pollution emission standard of garbage incineration plant, especially the emission index of NO X (nitrogen oxide).

[0003] The common way of existing treatment of nitrogen oxide used by garbage incineration plant includes: selective catalytic reduction method (SCR), selective non-catalytic reduction method (SNCR) and PNCR polymer denitration technology etc. The design complexity, cost and maintenance difficulty of SCR and PNCR are higher, while SNCR has lower investment, but there are problems of lower denitration efficiency, and ammonia escape increases and boiler water wall corrosion intensifies after increasing the amount of reactant. UTILITY MODEL CONTENT

[0004] The utility model provides a kind of denitration device for garbage incineration, which can effectively reduce the nitrogen oxide content of exhaust gas, and can avoid the problem of significant increase of ammonia escape caused by increasing the amount of urea or ammonia water.

[0005] The technical scheme adopted by the utility model is:

[0006] A kind of denitration device for garbage incineration, comprising:

[0007] Exhaust pipe, one end is communicated with the upper portion of incineration boiler;

[0008] Spraying system, including the storage container being set outside the exhaust pipe, the storage container is communicated with the spraying pump, the spraying pump is communicated with the injection assembly, the injection assembly is set on the exhaust pipe;And

[0009] Backflow system, including the backflow pump being set outside the exhaust pipe;The air inlet of the backflow system is communicated with the exhaust pipe, and the air outlet of the backflow system is communicated with the incineration boiler;

[0010] Among them, the communication place of the backflow system and the exhaust pipe is set on the pipe section after the injection assembly on the exhaust pipe, so that the backflow system can input the gas after combustion and denitration into the incineration boiler.

[0011] Further, the incineration boiler is provided with a plurality of grates, and the communication part of the backflow system with the incineration boiler is arranged above the plurality of grates.

[0012] Further, the plurality of grates comprises a drying grate, a combustion grate and a burnout grate arranged in the incineration boiler from top to bottom.

[0013] Further, the exhaust gas pipeline is divided into a first vertical section, a first horizontal section, a second vertical section and a second horizontal section from the exhaust gas inlet to the exhaust gas outlet.

[0014] Further, the first vertical section and the first horizontal section are internally provided with a baffle at the junction.

[0015] Further, the injection assembly comprises a first injection assembly arranged in the first vertical section, and the gas outlet of the backflow system communicates with the first injection assembly.

[0016] Further, the injection assembly further comprises a second injection assembly and a third injection assembly, wherein the second injection assembly is arranged in the first horizontal section, and the third injection assembly is arranged in the first horizontal section.

[0017] Further, the injection assembly further comprises a fourth injection assembly arranged in the second vertical section, and the second vertical section is internally provided with a catalyst layer.

[0018] Further, the storage container comprises an ammonia water storage container and a dilution liquid storage container, and the spray pump comprises a first spray pump and a second spray pump, wherein the first spray pump communicates with the ammonia water storage container, and the second spray pump communicates with the dilution liquid storage container.

[0019] Further, the exhaust gas pipeline is provided with an air induction assembly at the exhaust gas outlet.

[0020] The beneficial effects of the present application are as follows:

[0021] 1. The exhaust gas pipeline communicated with the incineration boiler is arranged, on one hand, a spray system is arranged on the exhaust gas pipeline to spray ammonia water into the exhaust gas pipeline to treat the generated nitrogen oxides, and on the other hand, a backflow system is arranged between the tail end of the exhaust gas pipeline and the incineration boiler to backflow the treated gas as secondary air, so that the generation of nitrogen oxides is also inhibited, thereby effectively reducing the content of nitrogen oxides in the tail gas generated by the incineration boiler in treating household garbage, and solving the problems of low denitration efficiency of the SNCR denitration technology in the prior art, and easy increase of ammonia escape and corrosion of the boiler water wall after increasing the amount of reactants. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 Structure diagram of the denitration device of the present application embodiment 1;

[0024] Figure 2 Structure diagram of the incineration boiler of the present application embodiment 1;

[0025] Figure 3 Structure diagram of the denitration device of the present application embodiment 2.

[0026] Reference signs: 100-incineration boiler, 110-feed inlet, 120-drying grate, 130-combustion grate, 140-combustion-out grate, 150-slagging outlet, 160-heating assembly, 170-air inlet;

[0027] 200-exhaust pipe, 210-first vertical section, 212-baffle, 220-first horizontal section, 230-second vertical section, 240-second horizontal section, 242-inducing air assembly;

[0028] 300-spraying system, 310-ammonia water storage container, 320-dilution liquid storage container, 330-first spraying pump, 340-second spraying pump, 350-first spraying assembly, 352-first control valve, 360-second spraying assembly, 362-second control valve, 370-third spraying assembly, 372-third control valve, 380-fourth spraying assembly, 382-fourth control valve, 390-catalyst layer;

[0029] 400-backflow system, 410-backflow pump, 420-dust removal and filtration assembly. DETAILED DESCRIPTION

[0030] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0031] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. For simplicity of the present application, the components and settings of specific examples are described in the following. Of course, they are only examples, and the purpose is not to limit the present application.

[0032] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0033] Embodiment 1

[0034] The existing SNCR denitration device is usually provided with a multilayer injection assembly system in the flue gas pipeline, but due to the difference of different heights and positions in the flue gas pipeline, the temperature difference is caused, and the reaction substances such as urea or ammonia water sprayed by the injection assembly are difficult to maintain stable denitration efficiency at different temperatures. Moreover, the standard of nitrogen oxides of environmental protection emission is continuously improved, and only by increasing the amount of urea or ammonia water can the emission requirement be met in the garbage incineration process, but increasing the amount will also cause the ammonia escape to increase to 20-40mg / Nm3, which will greatly increase the risk of boiler water wall corrosion, and is easy to cause shutdown or various safety accidents.

[0035] In order to solve the problem that the denitration efficiency of the SNCR denitration device in the prior art cannot meet the needs, the present embodiment provides a denitration device for garbage incineration, which is used for denitration of flue gas generated in the garbage incineration process. Compared with the existing SNCR denitration device, the denitration device for garbage incineration can effectively reduce the content of nitrogen oxides in the flue gas, and can avoid the significant increase of ammonia escape caused by increasing the amount of urea or ammonia water. Please refer to Figures 1-2 , the denitration device for garbage incineration mainly includes: a flue gas duct 200 and a spraying system 300.

[0036] The flue gas duct 200 is used to guide the flue gas generated in the garbage incineration process to be discharged along a certain path. For example Figure 1 , Figure 2As shown in the figure, the smoke exhaust duct 200 is communicated with the upper end of the incineration boiler 100 for incinerating garbage, and the incineration boiler 100 in the embodiment is a mechanical grate incinerator. The incineration boiler 100 is provided with a feeding port 110 near the top end, a slag discharge port 150 near the bottom end, and an inclined section between the feeding port 110 and the slag discharge port 150. The drying grate 120, the combustion grate 130 and the burnout grate 140 are sequentially arranged on the inclined section from top to bottom, and the heating assembly 160 is arranged on both sides of each grate. After the domestic garbage enters the furnace, the garbage first passes through the drying grate 120 for drying and preheating. At this time, in the high-temperature environment, the water in the garbage gradually evaporates and is taken away by the high-temperature flue gas, and at the same time, the temperature of the garbage is increased. The drying grate 120 can improve the combustion efficiency of the garbage and prepare for the subsequent combustion. After drying and preheating, the garbage enters the combustion grate 130. In the high-temperature environment of the combustion grate 130, the combustible substances in the garbage react with oxygen in the air to produce high-temperature flue gas and ash. The difference in the amount of air supplied during the combustion of the garbage on the combustion grate 130 will affect the complete combustion of the garbage, thereby changing the amount of harmful substances such as nitrogen oxides produced. The ash after combustion gradually cools down and forms clinkers on the burnout grate 140. Through the regular movement or vibration of the grate, the ash is discharged from the slag discharge port 150 outside the furnace. In addition, the air inlet 170 is arranged below the drying grate 120 of the incineration boiler 100 for introducing air as primary air to assist combustion.

[0037] The smoke exhaust duct 200 is sequentially divided into a first vertical section 210, a first horizontal section 220, a second vertical section 230 and a second horizontal section 240 between the end communicated with the upper end of the incineration boiler 100 and the end discharging flue gas. The first vertical section 210 is used for upwardly guiding the flue gas, the first horizontal section 220 guides the flue gas to the position for emission treatment, the second vertical section 230 guides the flue gas to flow downwardly so as to be discharged from the second horizontal section 240, and the tail of the second horizontal section 240 is provided with the air induction assembly 242 for providing power for the outward flow of the flue gas. In addition, the baffle 212 is arranged inside the junction of the first vertical section 210 and the first horizontal section 220. The baffle 212 is arranged obliquely in the smoke exhaust duct 200. The baffle 212 can adjust the slight negative pressure inside the furnace of the incineration boiler 100 and control the extraction of the flue gas, so as to make the work of the heating device in the heating furnace more stable and indirectly improve the furnace temperature and reduce unnecessary heat loss.

[0038] The spraying system 300 is used for spraying ammonia water solution to remove nitrogen oxides. The spraying system 300 mainly comprises a storage container and a spraying pump arranged outside the flue gas duct 200, a spraying assembly arranged on the flue gas duct 200, and a connecting pipeline between the storage container and the spraying pump. The storage container comprises an ammonia water storage container 310 and a dilution liquid storage container 320. The ammonia water storage container 310 is used to provide ammonia water which mainly reacts with nitrogen oxides. The dilution liquid storage container 320 is used to provide dilution water to adjust the concentration of ammonia water sprayed into the flue. The spraying pump comprises a first spraying pump 330 and a second spraying pump 340. The first spraying pump 330 is connected with the ammonia water storage container 310 and used to draw ammonia water into the pipeline. The second spraying pump 340 is connected with the dilution liquid storage container 320 and used to draw dilution liquid into the pipeline. In this embodiment, the ratio of ammonia water and dilution liquid can be controlled by adjusting the power of the first spraying pump 330 and the second spraying pump 340, so as to control the concentration of ammonia water sprayed into the flue gas duct 200. The spraying assembly of the spraying system 300 comprises a first spraying assembly 350, a second spraying assembly 360 and a third spraying assembly 370. The first spraying assembly 350 penetrates into the first vertical section 210 of the flue gas duct 200 and is located near the flue gas outlet of the incineration boiler 100. The second spraying assembly 360 and the third spraying assembly 370 both penetrate into the first horizontal section 220 of the flue gas duct 200. The second spraying assembly 360 is located near the front end of the pipeline, and the third spraying assembly 370 is located near the rear end of the pipeline. The first spraying assembly 350, the second spraying assembly 360 and the third spraying assembly 370 are connected with the first spraying pump 330 and the second spraying pump 340. Each spraying assembly is provided with a mixing pipeline to uniformly mix the two liquids, and then the mixed ammonia water solution is sprayed from the head of each spraying assembly penetrating into the flue gas duct 200 to fully contact with the flue gas.

[0039] The waste incineration denitration device of the embodiment further has a backflow system 400 for supplementing gas into the incineration boiler 100 and adjusting the gas composition in the incineration boiler 100. The backflow system 400 mainly comprises a backflow pump 410, a dust removal and filtration assembly 420 and a connecting pipeline. The backflow pump 410 is arranged outside the flue gas pipeline 200, and the gas inlet end of the backflow pump 410 is connected with the second horizontal section 240 of the flue gas pipeline 200, i.e. the connection between the gas inlet end of the backflow pump 410 and the flue gas pipeline 200 is located on the pipeline section of the flue gas pipeline 200 after the penetration of each injection assembly, so that the gas with low nitrogen oxide and oxygen contents after the combustion and ammonia water treatment can be extracted as secondary air gas and returned into the incineration boiler 100. The gas outlet end of the backflow pump 410 is connected with the upper part of the incineration boiler 100, and the dust removal and filtration assembly 420 is arranged on the connecting pipeline between the two, for reducing the dust content and avoiding the blockage of the small-diameter return pipeline. By returning the gas with low nitrogen oxide and oxygen contents into the incineration boiler 100 as the secondary air instead of the original air secondary air, on the one hand, the utilization rate of the flue gas waste heat is improved; on the other hand, in the embodiment, the connection between the gas outlet end of the backflow pump 410 and the incineration boiler 100 is located on the upper part of the grate of the incineration boiler 100, so that a turbulent flow zone can be formed on the upper part of the grate of the incineration boiler, the mixing of the flue gas in the furnace of the incineration boiler 100 is improved, the control of the combustion temperature and the nitrogen oxide concentration is realized, the flue gas temperature and the oxygen content in the local area are reduced, the formation of nitrogen oxides is inhibited, the nitrogen oxide content of the flue gas entering the flue gas pipeline 200 is lower, and the nitrogen oxide content of the flue gas discharged is also reduced, so that the more stringent environmental protection standard requirements can be met.

[0040] A specific working mode of the embodiment is as follows:

[0041] The living waste to be treated is put into the incineration boiler 100 from the feeding port 110, and the three grates and the heating assembly 160 of the incineration boiler 100 are started; the living waste is combusted in the incineration boiler 100 to generate ash and flue gas, the ash is discharged through the ash discharge port 150, and the flue gas is discharged through the flue gas pipeline 200 above; the flue gas is sprayed with ammonia water three times by the spraying system 300 in the flue gas pipeline 200, and then discharged from the second horizontal section 240 after the reduction of the nitrogen oxide content; meanwhile, part of the treated gas in the second horizontal section 240 is returned into the incineration boiler 100 through the backflow system 400, so as to inhibit the generation of nitrogen oxides in the incineration boiler 100.

[0042] In the present embodiment, the denitration device for waste incineration is provided with the flue gas discharge pipeline 200 communicated with the incineration boiler 100. On one hand, the spraying system 300 is arranged on the flue gas discharge pipeline 200 to spray the ammonia water into the flue gas discharge pipeline 200 to treat the generated nitrogen oxides. On the other hand, the backflow system 400 is arranged between the tail end of the flue gas discharge pipeline 200 and the incineration boiler 100 to discharge the treated gas as the secondary air, so that the generation of the nitrogen oxides is also inhibited, thereby effectively reducing the content of the nitrogen oxides in the tail gas generated by the incineration boiler 100 in treating the domestic waste, and solving the problems of the low denitration efficiency of the SNCR denitration technology in the prior art and the increase of the ammonia escape and the corrosion of the boiler water cooling wall after increasing the amount of the reactants.

[0043] In the present embodiment, the furnace wall of the incineration boiler 100 and the pipe wall of the flue gas discharge pipeline 200 are both provided with the water cooling wall. Because part of the heat is transferred to the furnace wall and the pipe wall through the ash and the air in the whole process, the conditions for heat recovery are provided. The water cooling wall is communicated with the waste heat power generation equipment (not shown in the figure), so that the heat generated by the waste combustion is fully utilized.

[0044] In addition, the first spraying assembly 350, the second spraying assembly 360 and the third spraying assembly 370 in the present embodiment all include 8 spray gun heads, and the 8 spray gun heads of each spraying assembly are arranged around the pipe wall of the flue gas discharge pipeline 200, so as to increase the contact area of the ammonia water solution and the flue gas, and further improve the denitration efficiency of the denitration device of the present embodiment. In the present embodiment, the first control valve 352, the second control valve 362 and the third control valve 372 are respectively arranged on the first spraying assembly 350, the second spraying assembly 360 and the third spraying assembly 370. When the desulfurization device works, the spraying amount of the second spraying assembly 360 and the third spraying assembly 370 can be reduced through the adjustment of each control valve, so as to avoid the formation of residual crystals in the pipeline due to the incomplete reaction of the ammonia water solution at the first horizontal section because of the low temperature, and cause the corrosion of the water cooling wall of the pipeline. In the present embodiment, the backflow pump 410 is also communicated with the first spraying assembly 350 through the dust removal and filtration assembly 420. Because the temperature of the flue gas at the first spraying assembly 350 is high, the atomization reaction efficiency of the sprayed ammonia water solution is low, and the denitration effect is poor. The spraying rate can be improved, the reaction area can be increased, and the gas temperature at the first spraying assembly 350 can be reduced by supplementing the secondary air through the backflow pump 410, so as to comprehensively strengthen the denitration effect.

[0045] Embodiment 2

[0046] On the basis of the above-mentioned embodiments, the spraying system 300 is deformed, and the second embodiment is provided as follows.

[0047] Please refer to Figure 3The second embodiment provides another denitration device for waste incineration, the spraying system 300 in the second embodiment is not provided with the second spraying assembly 360 and the third spraying assembly 370, but is provided with a fourth spraying assembly 380. The fourth spraying assembly 380 is also connected with the first spraying pump 330 and the second spraying pump 340, and is provided with a fourth control valve 382 on the connecting pipeline. Meanwhile, the fourth spraying assembly 380 penetrates into the second vertical section 230 and is located near the upper end of the second vertical section 230, and a catalyst layer 390 is arranged below the nozzle of the fourth spraying assembly 380 in the second vertical section 230, and the denitration efficiency and stability can be improved by cooperating with the sprayed ammonia water through the catalyst layer 390.

[0048] The basic principle, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A denitrification device for waste incineration, characterized in that, Include: The flue gas duct (200) is connected at one end to the upper part of the incineration boiler (100); A spray system (300) includes a storage container disposed outside the exhaust duct (200), the storage container being connected to a spray pump, the spray pump being connected to a spray assembly, the spray assembly being inserted into the exhaust duct (200); and The backflow system (400) includes a backflow pump (410) disposed outside the flue gas duct (200); the inlet of the backflow system (400) is connected to the flue gas duct (200), and the outlet of the backflow system (400) is connected to the incinerator (100); The connection between the backflow system (400) and the flue gas duct (200) is located on the pipe section after the injection assembly on the flue gas duct (200), so that the backflow system (400) can input the gas after combustion and denitrification into the incinerator (100).

2. The denitrification device for waste incineration as described in claim 1, characterized in that, The incineration boiler (100) is provided with several grates, and the connection between the reflux system (400) and the incineration boiler (100) is located above the several grates.

3. The denitrification device for waste incineration as described in claim 2, characterized in that, The plurality of grates include a drying grate (120), a combustion grate (130) and a burnout grate (140) arranged sequentially from top to bottom within the incineration boiler (100).

4. The denitrification device for waste incineration as described in claim 1, characterized in that, The exhaust duct (200) is divided into a first vertical section (210), a first horizontal section (220), a second vertical section (230) and a second horizontal section (240) from the flue gas inlet to the flue gas outlet.

5. The denitrification device for waste incineration as described in claim 4, characterized in that, A baffle (212) is provided inside the junction of the first vertical segment (210) and the first horizontal segment (220).

6. The denitrification device for waste incineration as described in claim 4, characterized in that, The injection assembly includes a first injection assembly (350), which is inserted into the first vertical section (210); the outlet of the return flow system (400) is connected to the first injection assembly (350).

7. The denitrification device for waste incineration as described in claim 6, characterized in that, The spraying assembly further includes a second spraying assembly (360) and a third spraying assembly (370); the second spraying assembly (360) is inserted into the first horizontal section (220); the third spraying assembly (370) is inserted into the first horizontal section (220).

8. The denitrification device for waste incineration as described in claim 6, characterized in that, The injection assembly further includes a fourth injection assembly (380); the fourth injection assembly (380) is inserted into the second vertical section (230), and a catalyst layer (390) is provided inside the second vertical section (230).

9. The denitrification device for waste incineration as described in claim 1, characterized in that, The storage container includes an ammonia storage container (310) and a diluent storage container (320); the spray pump includes a first spray pump (330) and a second spray pump (340), the first spray pump (330) being connected to the ammonia storage container (310) and the second spray pump (340) being connected to the diluent storage container (320).

10. The denitrification device for waste incineration as described in any one of claims 1-9, characterized in that, An exhaust fan assembly (242) is provided at the flue gas outlet of the exhaust duct (200).

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