Waste incineration flue gas purification and waste heat utilization device

Abstract

The utility model relates to the technical field of flue gas purification, in particular to a waste incineration flue gas purification and waste heat utilization device which comprises a grate furnace, a deacidification reaction tower, a denitration and dust removal integrated dust remover, a heat exchanger and a chimney which are sequentially connected through pipelines. The deacidification reaction tower is U-shaped, one side of the deacidification reaction tower is a descending section, and the other side of the deacidification reaction tower is an ascending section; a flue gas inlet is formed in the top of the descending section; a sodium bicarbonate injection opening and a calcium hydroxide injection opening are formed in the side wall of the upper part of the descending section; a flue gas outlet is formed in the top of the ascending section, and an activated carbon injection port and an ammonia water injection port are formed in the side wall of the upper part of the ascending section; a heat exchange outlet of the heat exchanger is connected with an inlet of the primary air pre-heater, an outlet of the primary air pre-heater is connected with an inlet of the circulating water pump, and an outlet of the circulating water pump is connected with a heat exchange inlet of the heat exchanger. According to the device, the flue gas purification efficiency is improved; and meanwhile, waste heat in the flue gas is recycled, so that the heat loss of the boiler is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of flue gas purification, particularly relates to a waste incineration flue gas purification and waste heat utilization device. BACKGROUND

[0002] The main pollutants of waste incineration flue gas are NOx, HCl, SO2, dust, Hg, dioxin and heavy metal. The conventional flue gas purification device includes a deacidification tower (for removing HCl and SOx), a bag filter (for removing dust, Hg, dioxin and heavy metal), and a denitration reaction tower (for removing NOx), which can meet the existing flue gas pollutant concentration emission standard. However, with the increasing environmental protection pressure and the improvement of pollutant emission standard, as well as the diversification of waste incineration species, the conventional flue gas purification device cannot meet the current environmental protection demand.

[0003] The problems faced by the conventional flue gas purification device include:

[0004] (1) The deacidifying agent used in the conventional deacidification tower is Ca(OH)2, which has a high efficiency in removing HCl. However, with the mixed burning of industrial waste, the concentration of SO2 increases significantly and is unstable. Meanwhile, after the concentration of HCl emission is upgraded, the existing device cannot meet the stable deacidification efficiency, so that HCl and SO2 can stably meet the emission standard.

[0005] (2) The conventional flue gas denitration adopts the SNCR+SCR mode, ammonia water is injected into the horizontal flue of the grate furnace to participate in the SNCR reaction, and a denitration reactor is arranged in the tail flue gas purification system to participate in the SCR reaction. A heat exchanger is usually arranged in the front part of the SCR reactor, and steam is used to heat the flue gas temperature to 280℃ to meet the reaction temperature window of the denitration catalyst. This mode consumes a large amount of steam and reduces the thermal efficiency of the boiler system.

[0006] (3) The exhaust gas temperature of the conventional flue gas purification device is 140-150℃, and the flue gas heat loss is large. INVENTION CONTENTS

[0007] The technical problem to be solved by the utility model is to provide a waste incineration flue gas purification and waste heat utilization device.

[0008] In order to solve the above technical problem, the present application provides the following technical scheme:

[0009] A waste incineration flue gas purification and waste heat utilization device, comprising a grate furnace, a deacidification reaction tower, a denitration and dust removal integrated dust remover, a heat exchanger and a chimney connected in sequence through pipelines.

[0010] The deacidification reaction tower is in the shape of "U", one side is a descending section, and the other side is an ascending section; the top of the descending section is a flue gas inlet, sodium bicarbonate spraying inlets and calcium hydroxide spraying inlets are arranged on the upper side wall of the descending section; the top of the ascending section is a flue gas outlet, activated carbon spraying inlets and ammonia water spraying inlets are arranged on the upper side wall of the ascending section;

[0011] The heat exchange outlet of the heat exchanger is connected with the inlet of the primary air air preheater, the outlet of the primary air air preheater is connected with the inlet of the circulating water pump, and the outlet of the circulating water pump is connected with the heat exchange inlet of the heat exchanger.

[0012] The sodium bicarbonate spraying inlets are arranged above the calcium hydroxide spraying inlets.

[0013] The lower side wall of the descending section is provided with ash removal holes.

[0014] The bottom of the deacidification reaction tower is provided with ash removal holes.

[0015] The activated carbon spraying inlets are arranged below the ammonia water spraying inlets.

[0016] The horizontal flue of the grate furnace is provided with an ammonia water inlet.

[0017] The flue gas temperature at the outlet of the grate furnace is 220 DEG C.

[0018] The flue gas temperature at the flue gas outlet is 210 DEG C.

[0019] The flue gas temperature at the outlet of the denitration and dust removal integrated dust remover is 200 DEG C.

[0020] The flue gas temperature at the outlet of the heat exchanger is 90-100 DEG C.

[0021] Compared with the prior art, the waste incineration flue gas purification and waste heat utilization device has at least the following beneficial effects:

[0022] The waste incineration flue gas purification and waste heat utilization device improves the flue gas purification efficiency; meanwhile, the waste heat in the flue gas is recycled and utilized, and the boiler heat loss is reduced.

[0023] A U-shaped deacidification tower is provided in this device. The inlet section of the deacidification tower is provided with NaHCO3 and Ca(OH)2 injection inlets, and NaHCO3 and Ca(OH)2 are used to jointly remove HCl and SO2 from the flue gas. At the same time, ammonia and activated carbon injection ports are provided at the outlet of the deacidification tower, where the activated carbon can capture dioxins and heavy metals in the dust collector. In addition, denitrification adopts the SNCR+ dust removal and denitrification method. The filter bag in the dust collector adopts a ceramic filter cartridge with a denitrification catalyst attached to the outer wall of the filter cartridge. Dust removal and denitrification are achieved simultaneously in the dust collector, and the denitrification reaction temperature is between 180-200℃. A heat exchanger for waste heat recovery is also provided to improve the thermal efficiency of the boiler.

[0024] The following is a further description of the waste incineration flue gas purification and waste heat utilization device of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Fig. 1 This is a schematic diagram of the utility model of the waste incineration flue gas purification and waste heat utilization device.

[0026] Fig. 2 Schematic diagram of the structure of the deacidification reaction tower.

[0027] Among them, 1-grate furnace; 2-deacidification reaction tower; 3-denitrification and dust removal integrated dust collector; 4-heat exchanger; 5-chimney; 6-primary air preheater; 7-circulating water pump; 21-flue gas inlet; 22-flue gas outlet; 23-sodium bicarbonate injection inlet; 24-calcium hydroxide injection inlet; 25-ash cleaning hole; 26-ash discharge hole; 27-activated carbon injection inlet; 28-ammonia injection inlet. DETAILED DESCRIPTION

[0028] like Figs. 1-2 As shown, a waste incineration flue gas purification and waste heat utilization device includes a grate furnace 1, a deacidification reaction tower 2, a denitrification and dust removal integrated dust collector 3, a heat exchanger 4 and a chimney 5 connected in sequence through pipelines;

[0029] The deacidification reaction tower 2 is U-shaped, with one side being a descending section and the other side being an ascending section. The top of the descending section is provided with a flue gas inlet 21, and the upper side wall of the descending section is provided with a sodium bicarbonate injection port 23 and a calcium hydroxide injection port 24. The top of the ascending section is provided with a flue gas outlet 22, and the upper side wall of the ascending section is provided with an activated carbon injection port 27 and an ammonia injection port 28.

[0030] The heat exchange outlet of the heat exchanger 4 is connected to the inlet of the primary air preheater 6 , the outlet of the primary air preheater 6 is connected to the inlet of the circulating water pump 7 , and the outlet of the circulating water pump 7 is connected to the heat exchange inlet of the heat exchanger 4 .

[0031] The sodium bicarbonate injection port 23 is located above the calcium hydroxide injection port 24. The lower part of the side wall of the descending section is provided with a dust removal hole 25, and the bottom of the deacidification reaction tower 2 is provided with a dust removal hole 26. The activated carbon injection port 27 is located below the ammonia water injection port 28.

[0032] The horizontal flue of the grate furnace 1 is provided with an ammonia water inlet. The flue gas temperature at the outlet of the grate furnace 1 is 220℃. The flue gas temperature at the flue gas outlet 22 is 210℃. The flue gas temperature at the outlet of the denitration and dust removal integrated dust remover 3 is 200℃. The flue gas temperature at the outlet of the heat exchanger 4 is 90-100℃.

[0033] The filter bag in the denitration and dust removal integrated dust remover 3 uses a ceramic filter cartridge (for example, a ceramic filter cartridge produced by Bidafo Environmental Technology Co., Ltd. or Shanghai Lingqiao Environmental Protection Equipment Factory Co., Ltd. can be used), and the outer wall of the filter cartridge is attached with a denitration catalyst.

[0034] The working method of the garbage incineration flue gas purification and waste heat utilization device is as follows:

[0035] (1) Ammonia water is injected in front of the horizontal flue of the grate furnace, and SNCR reaction occurs in the range of 800-1000℃ to remove NOx in the flue gas;

[0036] (2) The flue gas enters the deacidification reaction tower inlet from the horizontal flue outlet, and the flue gas temperature is 220℃. NaHCO3 and Ca(OH)2 are injected in sequence at the inlet of the descending section of the reaction tower to remove HCl and SO2 in the flue gas;

[0037] (3) Activated carbon and ammonia water are injected in sequence before the outlet of the ascending section of the deacidification reaction tower, and the ammonia water is vaporized into ammonia gas under the high-temperature flue gas of 210℃;

[0038] (4) After the flue gas passes through the deacidification tower, the temperature decreases to 210℃, and the flue gas enters the denitration and dust removal integrated dust remover, where the activated carbon on the wall of the ceramic filter cartridge adsorbs heavy metals and dioxins in the flue gas and is attached to the cartridge wall. At the same time, due to the fact that the ceramic filter cartridge wall surface is also attached with a low-temperature catalyst, in the range of 180-220℃, the NOx in the flue gas reacts with ammonia gas to further remove NOx through SCR reaction;

[0039] (5) After the flue gas passes through the dust remover, the temperature decreases to 200℃, and then enters the heat exchanger, where it is indirectly heated with water. The flue gas temperature decreases from 200℃ to 90-100℃, and finally the flue gas is discharged into the atmosphere through the chimney;

[0040] (6) The desalted water is used in the heat exchanger to exchange heat with the flue gas. The water is transported into the heat exchanger by a circulating water pump. After heat exchange, the water temperature increases by 10-12℃. The heated water enters the primary air preheater to heat the cold air, reducing the energy consumption of the primary air preheater cold air heating and improving the utilization rate of flue gas waste heat.

[0041] Compared with the traditional flue gas purification device, the advantages of the device mainly include:

[0042] (1) NaHCO3 and Ca(OH)2 are used for deacidification, which improves the deacidification efficiency, meets the demand after the current emission standard is improved, and can realize stable standard reaching of HCl and SO2;

[0043] (2) A deacidification reaction tower is arranged, including a descending section and an ascending section, NaHCO3 and Ca(OH)2 are sprayed at the entrance of the deacidification tower, i.e. the entrance of the descending section, and the deacidification reaction is completed when the flue gas passes through the descending section and the ascending section; ammonia water and activated carbon are sprayed at the outlet of the deacidification tower, i.e. the ascending section, the ammonia water is vaporized into ammonia gas, and they are introduced into the dust remover to remove dioxin, heavy metal and NOx.

[0044] (3) The SNCR+SCR method is still used for denitration, but the SCR reaction tower is cancelled, the low-temperature denitration catalyst is attached in the ceramic filter cartridge of the dust remover, the denitration SCR reaction is carried out while dust removal, and the steam energy consumption required by the original SCR reaction is reduced.

[0045] The above-described embodiments are only used to describe the preferred embodiments of the present application, and do not limit the scope of the present application, and various deformations and improvements of the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope determined by the claims of the present application.

Claims

1. A waste incineration flue gas purification and waste heat utilization device, characterized by: The furnace (1), the deacidification reaction tower (2), the denitration and dust removal integrated dust remover (3), the heat exchanger (4) and the chimney (5) are sequentially connected by pipelines; The deacidification reaction tower (2) is in a "U" shape, one side of which is a descending section and the other side of which is an ascending section; the top of the descending section is a flue gas inlet (21), and the upper side wall of the descending section is provided with a sodium bicarbonate spraying inlet (23) and a calcium hydroxide spraying inlet (24); the top of the ascending section is provided with a flue gas outlet (22), and the upper side wall of the ascending section is provided with an activated carbon spraying inlet (27) and an ammonia water spraying inlet (28); The heat exchange outlet of the heat exchanger (4) is connected with the inlet of the primary air air preheater (6), the outlet of the primary air air preheater (6) is connected with the inlet of the circulating water pump (7), and the outlet of the circulating water pump (7) is connected with the heat exchange inlet of the heat exchanger (4).

2. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The sodium bicarbonate spraying inlet (23) is located above the calcium hydroxide spraying inlet (24).

3. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The lower side wall of the descending section is provided with a dust cleaning hole (25).

4. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The bottom of the deacidification reaction tower (2) is provided with an ash discharge hole (26).

5. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The activated carbon spraying inlet (27) is located below the ammonia water spraying inlet (28).

6. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The horizontal flue of the furnace (1) is provided with an ammonia water inlet.

7. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The flue gas temperature at the outlet of the furnace (1) is 220 DEG C.

8. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The flue gas temperature at the flue gas outlet (22) is 210 DEG C.

9. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The flue gas temperature at the outlet of the denitration and dust removal integrated dust remover (3) is 200 DEG C.

10. The waste incineration flue gas cleaning and waste heat utilization device according to claim 1, characterized in that: The flue gas temperature at the outlet of the heat exchanger (4) is 90-100 DEG C.

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