Flue gas purification ultralow emission device for combined boiler

Abstract

The utility model provides a flue gas purification ultralow emission device for a combined boiler, and belongs to the technical field of boiler flue gas purification. The problem that gas pollutant emission of an existing large and medium-sized coal-fired boiler needs to be ultralow is solved. The system comprises a coal-fired boiler, SNCR (selective non-catalytic reduction) denitration equipment, SCR (selective catalytic reduction) denitration equipment, a flue gas cooling dry-type desulfurization reactor, a bag-type dust collector and limestone desulfurization equipment, the SNCR denitration equipment is connected with the interior of the coal-fired boiler, the SCR denitration reactor is connected to the tail of the coal-fired boiler, the SNCR denitration equipment is connected with the inlet end of the SCR denitration reactor, and the inlet end of the SCR denitration reactor is connected with the outlet end of the bag-type dust collector. The outlet end of the SCR denitration reactor is sequentially connected with a flue gas cooling dry-type desulfurization reactor, a bag-type dust collector and limestone desulfurization equipment. The boiler flue gas purifier is mainly used for boiler flue gas purification.

Description

Technical Field

[0001] The utility model belongs to the technical field of boiler flue gas purification, in particular to an ultra-low emission device for flue gas purification of a combined boiler. Background Art

[0002] SO2 emitted by large and medium-sized coal-fired boilers during production 2 、NO X Gaseous pollutants such as smoke and dust will pollute the ambient air and endanger human health. Therefore, gaseous pollutant emissions have always been the core evaluation indicators of the production and operation of large and medium-sized coal-fired boiler enterprises. Gaseous pollutant emissions are directly related to people's livelihood and are a direct display window for the image of large and medium-sized coal-fired boiler enterprises. Therefore, to further improve the environmental protection requirements of cogeneration units and coal-fired boilers, cogeneration units and coal-fired boilers in urban areas must achieve ultra-low emissions. How to achieve ultra-low emissions of large and medium-sized coal-fired boilers in the production process is a technical problem that needs to be solved in the existing gas pollutant emission technology of large and medium-sized coal-fired boilers. Utility Model Content

[0003] In view of this, the utility model aims to propose a combined boiler flue gas purification ultra-low emission device to solve the technical problem of achieving ultra-low emissions of gas pollutants from existing large and medium-sized coal-fired boilers.

[0004] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a combined boiler flue gas purification ultra-low emission device, which includes a coal-fired boiler, an SNCR denitrification device, an SCR denitrification device, a flue gas cooling dry desulfurization reactor, a bag dust collector and a limestone desulfurization device, the SNCR denitrification device is connected to the furnace of the coal-fired boiler, the SCR denitrification reactor is connected to the tail of the coal-fired boiler, the SNCR denitrification device is connected to the inlet end of the SCR denitrification reactor, and the outlet end of the SCR denitrification reactor is connected to the flue gas cooling dry desulfurization reactor, the bag dust collector and the limestone desulfurization equipment in sequence.

[0005] Furthermore, the flue gas cooling dry desulfurization reactor includes a cooling reaction zone, a sedimentation zone and a baking soda desulfurization integrated machine. The sedimentation zone is arranged at the bottom of the cooling reaction zone. A cyclone is arranged inside the cooling reaction zone. The inlet end of the cyclone is connected to the outlet end of the SCR denitrification reactor, and the outlet end of the cyclone is connected to the inlet end of the bag filter. A cold water wall is arranged around the outer side of the cooling reaction zone. The inlet end of the cold water wall is connected to a cooling water inlet pipe, and the outlet end of the cold water wall is connected to the limestone desulfurization equipment, and the outlet end of the baking soda desulfurization integrated machine is connected to the inlet end of the cyclone.

[0006] Furthermore, a slag discharge pipe is connected to the bottom of the settling zone of the flue gas cooling dry desulfurization reactor.

[0007] Furthermore, the limestone desulfurization equipment includes a limestone silo, a desulfurizer dissolving tank and a desulfurization reaction tower. The discharge port of the limestone silo is connected to the feed port of the desulfurizer dissolving tank, the outlet end of the desulfurizer dissolving tank is connected to the feed port of the desulfurization reaction tower, the outlet end of the cold water wall is connected to the water inlet of the desulfurizer dissolving tank, and the outlet end of the bag dust collector is connected to the air inlet of the desulfurization reaction tower.

[0008] Furthermore, the combined boiler flue gas purification ultra-low emission device also includes an air compressor unit, and the air compressor unit is respectively connected to the coal-fired boiler, the SCR denitrification reactor and the bag filter.

[0009] Furthermore, an induced draft unit is arranged between the outlet end of the bag filter and the air inlet of the desulfurization reaction tower, and the outlet end of the induced draft unit is respectively connected to the air inlet of the desulfurization reaction tower and the air inlet of the baking soda desulfurization integrated machine.

[0010] Furthermore, the outlet end of the desulfurization reaction tower is connected to the chimney.

[0011] Compared with the prior art, the beneficial effects of the utility model are:

[0012] 1. The utility model combines the flue gas cooling dry desulfurization reactor and the bag filter to achieve the secondary treatment of the smoke particles in the gas pollution emissions. The content of smoke particles in the treated gas pollution emissions is less than 10mg / Nm 3 Within 100000 square meters, ultra-low emission of soot particles in gaseous pollution emissions was achieved;

[0013] 2. The utility model combines the flue gas cooling dry desulfurization reactor and the limestone desulfurization equipment to achieve the desulfurization of sulfur dioxide SO in gaseous pollution emissions. 2 After secondary treatment, sulfur dioxide SO in the treated gaseous pollutant emissions 2 The content is 35mg / Nm 3 Within 100%, sulfur dioxide SO in gaseous pollution emissions was reduced to 2 Ultra-low emissions;

[0014] 3. The utility model realizes the removal of nitrogen oxides NO in gaseous pollutant emissions by combining SNCR denitrification equipment and SCR denitrification equipment. X After secondary treatment, nitrogen oxides NO in the treated gaseous pollutant emissions X The content is 50mg / Nm 3 Within 100%, the nitrogen oxides NO in gaseous pollution emissions were reduced to X Ultra-low emissions;

[0015] 4. The utility model is provided with a flue gas cooling dry desulfurization reactor. By respectively arranging cyclones and cooling cold water walls inside and outside the cooling reaction zone of the flue gas cooling dry desulfurization reactor, the gaseous pollutant emissions are separated from the gas and smoke particles under the action of the cyclone, while the cooling of the flue gas is accelerated. The cooling cold water wall is used for heat exchange, which effectively reduces the temperature of the flue gas and prevents the flue gas temperature from being too high to damage the dust bags in the next-stage bag filter, thereby affecting the service life and dust removal efficiency of the dust bags.

[0016] 5. The utility model has a simple structure, is easy to use, easy to maintain and has low operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0018] Figure 1 It is a schematic diagram of the overall structure of a combined boiler flue gas purification ultra-low emission device described in the utility model.

[0019] 1-coal-fired boiler, 2-SNCR denitrification equipment, 3-SCR denitrification equipment, 4-SCR denitrification reactor, 5-flue gas cooling dry desulfurization reactor, 6-bag dust collector, 7-baking soda desulfurization integrated machine, 8-air compressor unit equipment, 9-limestone silo, 10-desulfurizer dissolving tank, 11-desulfurization reaction tower, 12-induced draft unit, 13-cooling reaction zone, 14-sedimentation zone, 15-chimney. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely explain the technical solutions in the embodiments of the utility model. It should be noted that the embodiments and features in the embodiments of the utility model can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the utility model, not all of the embodiments.

[0021] See also Figure 1The present embodiment is described as a combined boiler flue gas purification ultra-low emission device, which includes a coal-fired boiler 1, an SNCR denitration device 2, an SCR denitration device 3, a flue gas cooling dry desulfurization reactor 5, a bag filter 6 and a limestone desulfurization device. The SNCR denitration device 2 is connected to the furnace of the coal-fired boiler 1, and the SCR denitration reactor 4 is connected to the furnace tail of the coal-fired boiler 1. The SNCR denitration device 2 is connected to the inlet end of the SCR denitration reactor 4, and the outlet end of the SCR denitration reactor 4 is sequentially connected to the flue gas cooling dry desulfurization reactor 5, the bag filter 6 and the limestone desulfurization device. In this embodiment, the flue gas cooling dry desulfurization reactor 5 and the bag filter 6 are combined to achieve secondary treatment of the smoke particles in the gaseous pollution emissions. The content of the smoke particles in the treated gaseous pollution emissions is less than 10 mg / Nm 3 The ultra-low emission of soot particles in gaseous pollution emissions is achieved within 50000 square meters. The combination of flue gas cooling dry desulfurization reactor 5 and limestone desulfurization equipment is used to achieve the reduction of sulfur dioxide SO in gaseous pollution emissions. 2 After secondary treatment, sulfur dioxide SO in the treated gaseous pollutant emissions 2 The content is 35mg / Nm 3 Within 100%, sulfur dioxide SO in gaseous pollution emissions was reduced to 2 Ultra-low emissions, and through the combination of SNCR denitrification equipment 2 and SCR denitrification equipment 3, the nitrogen oxides NO in the gaseous pollution emissions are reduced. X After secondary treatment, nitrogen oxides NO in the treated gaseous pollutant emissions X The content is 50mg / Nm 3 Within 100%, the nitrogen oxides NO in gaseous pollution emissions were reduced to X The ultra-low emission makes the gaseous pollution emissions of boiler flue gas meet the ultra-low emission requirements under the action of the ultra-low emission device for flue gas purification of combined boilers.

[0022] In this embodiment, the SNCR denitrification equipment 2 is used to transport urea into the coal-fired boiler 1 to achieve denitrification treatment, and the SCR denitrification equipment 3 is used to transport urea to the SCR denitrification reactor 4 at the tail of the coal-fired boiler 1 to achieve secondary denitrification treatment of flue gas. The structures and denitrification principles of the SNCR denitrification equipment 2, the SCR denitrification equipment 3 and the SNCR denitrification equipment 2 are all existing technologies and will not be elaborated here.

[0023] The flue gas cooling dry desulfurization reactor 5 in this embodiment includes a cooling reaction zone 13, a sedimentation zone 14 and a baking soda desulfurization integrated machine 7, the sedimentation zone 14 is arranged at the bottom of the cooling reaction zone 13, a cyclone is arranged inside the cooling reaction zone 13, the inlet end of the cyclone is connected to the outlet end of the SCR denitration reactor 4, the outlet end of the cyclone is connected to the inlet end of the bag filter 6, the outer side of the cooling reaction zone 13 is surrounded by a cold water wall, the inlet end of the cold water wall is connected to a cooling water inlet pipe, the outlet end of the cold water wall is connected to the limestone desulfurization equipment, the outlet end of the baking soda desulfurization integrated machine 7 is connected to the inlet end of the cyclone, the bottom of the sedimentation zone 14 of the flue gas cooling dry desulfurization reactor 5 in this embodiment is connected to a slag discharge pipe, the cyclone can make the flue gas entering the cooling reaction zone 13 produce a swirl, the flue gas in the cooling reaction zone 13 is separated from the smoke particles and gas under the action of centrifugal force, and the separated smoke particles The particles fall into the settling area 14 under the action of gravity and are discharged through the slag discharge pipe. Under the action of the cyclone, the gas and smoke particles are separated, and the cooling of the flue gas is accelerated. The process cooling water in the cooling water wall is used to exchange heat with the flue gas, which effectively reduces the temperature of the flue gas and prevents the flue gas from being too hot and causing damage to the dust bags in the next-level bag filter, thereby affecting the service life and dust removal efficiency of the dust bags. The heat exchange water can be continuously supplied to the limestone desulfurization equipment through the process water pump for continued use. A baking soda desulfurization integrated machine 7 is installed at the inlet of the flue gas cooling dry desulfurization reactor 5, so that the desulfurizer, that is, the baking soda ultrafine powder, is sprayed into the reactor through the pneumatic conveying injector, and is evenly mixed with the flue gas through the cyclone to increase the reaction time. The baking soda ultrafine powder is designed to stay for more than two seconds in the flue gas cooling dry desulfurization reactor 5 and the bag filter 6, achieving a high-efficiency desulfurization effect while reducing the temperature of the flue gas entering the bag filter 6.

[0024] In this embodiment, the flue gas cooling dry desulfurization reactor 5 uses baking soda NaHCO 3 As a desulfurizer, it is activated by high-temperature flue gas at 140-160℃, and a microporous structure is formed on the surface. The flue gas in the flue fully contacts with the activated desulfurizer to react chemically, and the SO in the flue gas is reduced. 2 And other acidic media are absorbed and purified, absorbed and dried sodium sulfate Na 2 SO 4 The solid by-products are collected in the bag filter 6 along with the air flow.

[0025] The flue gas cooling dry desulfurization reactor 5 described in this embodiment can cool the flue gas after the boiler by 5-20°C, the flue gas desulfurization efficiency can reach more than 70%, the particulate dust reduction efficiency can reach more than 50%, and the equipment resistance is designed to be less than 700Pa.

[0026] The limestone desulfurization equipment in this embodiment includes a limestone silo 9, a desulfurizer dissolving tank 10 and a desulfurization reaction tower 11. The discharge port of the limestone silo 9 is connected to the feed port of the desulfurizer dissolving tank 10, the outlet end of the desulfurizer dissolving tank 10 is connected to the feed port of the desulfurization reaction tower 11, the outlet end of the cold water wall is connected to the water inlet of the desulfurizer dissolving tank 10, the outlet end of the bag filter 6 is connected to the air inlet of the desulfurization reaction tower 11, the limestone silo 9 is used to provide limestone to the desulfurizer dissolving tank 10, the heat exchange water in the flue gas cooling dry desulfurization reactor 5 enters the desulfurizer dissolving tank 10 and mixes with the limestone to form a limestone desulfurizer solution, and the limestone desulfurizer solution is transported to the desulfurization reaction tower 11 to mix with sulfur dioxide SO in the flue gas. 2 The reaction is carried out to achieve further desulfurization of the flue gas.

[0027] The combined boiler flue gas purification ultra-low emission device described in this embodiment also includes an air compressor unit 8, which is respectively connected to the coal-fired boiler 1, the SCR denitration reactor 4 and the bag-type dust collector 6. The air compressor unit 8 is used to provide power to the smoke in the coal-fired boiler 1, the SCR denitration reactor 4 and the bag-type dust collector 6 to ensure that the smoke flows smoothly to the next-level equipment.

[0028] In this embodiment, an induced draft unit 12 is arranged between the outlet end of the bag-type dust collector 6 and the air inlet of the desulfurization reaction tower 11. The outlet end of the induced draft unit 12 is respectively connected to the air inlet of the desulfurization reaction tower 11 and the air inlet of the baking soda desulfurization integrated machine 7. The induced draft unit 12 is used to lead the flue gas in the bag-type dust collector 6 to the desulfurization reaction tower 11 for desulfurization treatment.

[0029] The outlet end of the desulfurization reaction tower 11 in this embodiment is connected to the chimney 15 . After the flue gas is desulfurized by the desulfurization reaction tower 11 , the purified flue gas is discharged from the chimney 15 .

[0030] This embodiment has a simple structure, is easy to use, easy to maintain and has low operating costs.

[0031] The coal-fired boiler flue gas treatment process of this embodiment is as follows:

[0032] The flue gas generated by the coal-fired boiler 1 is subjected to primary denitrification treatment by the SNCR denitrification equipment 2 in the furnace of the coal-fired boiler 1, and is subjected to secondary denitrification treatment by the combined medium-temperature SCR denitrification reactor 4 at the tail of the furnace. The flue gas then enters the flue gas cooling dry desulfurization reactor 5 for primary baking soda desulfurization treatment, primary dust removal treatment and cooling. The cooled flue gas enters the bag filter 6 for secondary dust removal treatment, and then the flue gas enters the desulfurization reaction tower 11 under the action of the induced draft unit 12 for secondary limestone-gypsum desulfurization treatment. The treated flue gas meets the ultra-low emission standard, and the flue gas that finally meets the ultra-low emission standard is discharged from the chimney 15.

[0033] The embodiments of the utility model disclosed above are only used to help explain the utility model. The embodiments do not describe all the details in detail, nor do they limit the utility model to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the utility model, so that technicians in the relevant technical field can well understand and use the utility model.

Claims

1. A combined boiler flue gas purification ultra-low emission device, characterized in that: The invention comprises a coal-fired boiler (1), a SNCR denitration device (2), an SCR denitration device (3), a flue gas cooling dry desulfurization reactor (5), a bag filter (6) and a limestone desulfurization device. The SNCR denitration device (2) is connected to the furnace of the coal-fired boiler (1). The furnace tail of the coal-fired boiler (1) is connected to an SCR denitration reactor (4). The SNCR denitration device (2) is connected to the inlet end of the SCR denitration reactor (4). The outlet end of the SCR denitration reactor (4) is connected to the flue gas cooling dry desulfurization reactor (5), the bag filter (6) and the limestone desulfurization device in sequence.

2. The ultra-low emission device for flue gas purification for a combined boiler according to claim 1, characterized in that: The flue gas cooling dry desulfurization reactor (5) comprises a cooling reaction zone (13), a settling zone (14) and a baking soda desulfurization integrated machine (7), wherein the settling zone (14) is arranged at the bottom of the cooling reaction zone (13), a cyclone is arranged inside the cooling reaction zone (13), the inlet end of the cyclone is connected to the outlet end of the SCR denitration reactor (4), the outlet end of the cyclone is connected to the inlet end of the bag filter (6), a cold water wall is arranged around the outer side of the cooling reaction zone (13), the inlet end of the cold water wall is connected to a cooling water inlet pipe, the outlet end of the cold water wall is connected to a limestone desulfurization device, and the outlet end of the baking soda desulfurization integrated machine (7) is connected to the inlet end of the cyclone.

3. The ultra-low emission device for flue gas purification for a combined boiler according to claim 2, characterized in that: The bottom of the settling area (14) of the flue gas cooling dry desulfurization reactor (5) is connected to a slag discharge pipeline.

4. The ultra-low emission device for flue gas purification for a combined boiler according to claim 2, characterized in that: The limestone desulfurization equipment comprises a limestone silo (9), a desulfurization agent dissolving tank (10) and a desulfurization reaction tower (11); the discharge port of the limestone silo (9) is connected to the feed port of the desulfurization agent dissolving tank (10); the outlet end of the desulfurization agent dissolving tank (10) is connected to the feed port of the desulfurization reaction tower (11); the outlet end of the cold water wall is connected to the water inlet of the desulfurization agent dissolving tank (10); and the outlet end of the bag filter (6) is connected to the air inlet of the desulfurization reaction tower (11).

5. The ultra-low emission device for flue gas purification for a combined boiler according to claim 1, characterized in that: The combined boiler flue gas purification ultra-low emission device also includes an air compressor unit (8), and the air compressor unit (8) is respectively connected to the coal-fired boiler (1), the SCR denitration reactor (4) and the bag filter (6).

6. The ultra-low emission device for flue gas purification for a combined boiler according to claim 4, characterized in that: An induced draft unit (12) is provided between the outlet end of the bag filter (6) and the air inlet of the desulfurization reaction tower (11), and the outlet end of the induced draft unit (12) is respectively connected to the air inlet of the desulfurization reaction tower (11) and the air inlet of the baking soda desulfurization integrated machine (7).

7. The ultra-low emission device for flue gas purification for a combined boiler according to claim 4, characterized in that: The outlet end of the desulfurization reaction tower (11) is connected to a chimney (15).

Images