CN210319998U

CN210319998U - Air return combustion-supporting device of layer combustion boiler

Info

Publication number: CN210319998U
Application number: CN201921212324.6U
Authority: CN
Inventors: 李志宏; 李金泽
Original assignee: Hebei Hongze Boiler Manufacturing Co ltd
Current assignee: Hebei Hongze Boiler Manufacturing Co ltd
Priority date: 2019-07-30
Filing date: 2019-07-30
Publication date: 2020-04-14
Anticipated expiration: 2029-07-30

Abstract

The utility model discloses a layer fires combustion-supporting device of boiler return air belongs to layer and fires boiler technical field for on the layer fires coal fired boiler system, including the return air duct that is used for carrying combustion-supporting return air, the return air induced air mouth of return air duct set up in the exit of boiler system's draught fan, the return air outlet of return air duct set up in the air intake department of boiler system's air-blower, the air-blower is with the combustion-supporting return air of return air duct feed back again the boiler system's layer fires boiler body and participates in the reburning. The utility model discloses the combustion-supporting device of layer combustion boiler return air can reduce boiler excess air coefficient, restraines boiler nitrogen oxide's production, reduces the smoke emission, improves boiler heat production efficiency.

Description

Air return combustion-supporting device of layer combustion boiler

Technical Field

The utility model relates to a layer fires boiler technical field, especially relates to a layer fires combustion-supporting device of boiler return air.

Background

The grate-firing boilers in China mainly use fire coal, wherein the grate-firing boilers account for 93.7 percent of the total number of boilers, and the room-fired boilers and circulating fluidized bed boilers only account for 6.3 percent of the total number of boilers. According to the measured data, the total evaporation capacity of the existing coal-fired grate-fired boiler in China is 250 ten thousand t/h, and accounts for about 85 percent of the total number and the total evaporation capacity of the grate-fired boilers in China. The raw coal is consumed by about 6.9 million t each year, and the emission of nitrogen oxides is 271 million t. The efficiency of the grate-firing boiler is low, and the concentration of NOx discharged by combustion to human health is generally 400-800 mg/m. The combustion conditions, fuels, boiler structures, operation loads, operation conditions and the like of the grate-firing boiler change greatly, and the development difficulty of low-nitrogen combustion technology and equipment is high. At present, the low-nitrogen combustion technology of the boiler is researched later in China, and further pilot-scale test and industrial application experiments are needed. At present, NOx control technology is not adopted in most domestic grate-fired boilers. The load of the grate-firing boiler is unstable, the excess air coefficient is difficult to control, and too much cold air is supplied in the combustion process of the boiler, so that the waste of fuel is caused.

Therefore, it is an urgent technical problem to be solved by those skilled in the art to develop a combustion-supporting device for return air of a layer-combustion boiler to overcome the above-mentioned drawbacks.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a layer combustion boiler return air combustion-supporting device can reduce the boiler excess air coefficient, restraines boiler nitrogen oxide's production, reduces the smoke emission, improves boiler heat production efficiency.

In order to solve the technical problem, the utility model adopts the following technical scheme:

the utility model relates to a layer fires combustion-supporting device of boiler return air for on the layer fires coal fired boiler system, including the return air pipe that is used for carrying combustion-supporting return air, the return air induced air mouth of return air pipe set up in the exit of boiler system's draught fan, the return air outlet of return air pipe set up in the air intake department of boiler system's air-blower, the air-blower is gone into with the combustion-supporting return air that the return air pipe sent back again boiler system's layer fires boiler body and participates in the reburning.

Furthermore, an adjustable windshield for adjusting the combustion-supporting return air quantity is arranged on the return air pipe, and the adjustable windshield is positioned at the return air inlet end of the return air pipe.

Furthermore, a temperature sensor for measuring the temperature of the combustion-supporting return air is arranged on the return air pipe, and the temperature sensor is arranged in the return air pipe and at the air inlet end of the return air.

Furthermore, the outer wall periphery of return air pipe has heat preservation and inoxidizing coating.

Compared with the prior art, the utility model discloses a beneficial technological effect:

the utility model relates to a layer fires boiler return air combustion-supporting device, the boiler flue gas after leading back the dust removal through the return air duct sends into layer and fires boiler body and participates in the reburning, because of the low oxygen content of boiler flue gas and have certain temperature and send to the grate through the air-blower and can play the combustion-supporting role, the low oxygen environment can make the flame temperature more even, has reduced the coal-fired coking, the fuel burning is more abundant; excessive low-temperature air heating is avoided, and fuel is saved; the exhaust emission is reduced, the waste heat of the flue gas is recycled, the heat efficiency of the boiler is improved, and in the process of reburning, because the low-oxygen environment reduces the generation of nitrogen oxides, part of CO2 can be reduced into CO to play a role in supporting combustion, increasing the heat efficiency and reducing the heat loss.

In addition, through the arrangement of the adjustable windshield, the air return quantity can be controlled according to the load of the boiler and the excess air coefficient of the flue gas of the boiler; the over-temperature sensor is arranged, so that the temperature of the combustion-supporting return air introduced by the return air induction opening can be conveniently monitored, and corresponding adjustment work can be carried out according to a temperature signal; the heat preservation layer and the protective layer can reduce heat dissipation loss when the return air pipe conveys combustion-supporting return air, ensure high-temperature recycling of the combustion-supporting return air, improve heat energy utilization and further improve the efficiency of the layer combustion coal-fired boiler system.

Drawings

The present invention will be further explained with reference to the following description of the drawings.

FIG. 1 is a schematic structural view of the combustion-supporting device of the layer combustion boiler;

FIG. 2 is a schematic view of the top view structure of the air return combustion-supporting device of the grate-fired boiler of the present invention;

description of reference numerals: 1. a blower; 2. a fresh air duct; 3. a grate-fired boiler body; 4. a flue; 5. a coal economizer; 6. a multi-tube dust collector; 7. a bag-type dust collector; 8. an induced draft fan; 9. a desulfurization and denitrification unit; 10. a chimney; 11. an air return air inlet; 12. a return air duct; 13. an air return outlet; 14. an adjustable damper; 15. a temperature sensor.

Detailed Description

The core of the utility model is to provide a layer combustion boiler return air combustion-supporting device can reduce boiler excess air coefficient, restraines boiler nitrogen oxide's production, reduces the smoke emission, improves boiler heat production efficiency.

In the following, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply specific orientations that the designated devices or elements must have and specific orientation configurations, and thus, should not be construed as limiting the present invention.

In a specific embodiment, as shown in fig. 1 and 2, a combustion-supporting device of layer combustion boiler return air for on the layer combustion coal fired boiler system, including the return air pipe 12 that is used for carrying combustion-supporting return air, the return air induced air mouth 11 of return air pipe 12 is seted up in the exit of boiler system's draught fan 8, the return air outlet 13 of return air pipe 12 is seted up in boiler system's air intake department of blower 1, blower 1 is with the combustion-supporting return air that return air pipe 12 sent back to swell again boiler system's layer combustion boiler body 3 participates in the reburning.

Through the reasonable setting of return air pipe 12, combustion-supporting return air is mixed together with the new trend and is gone into layer combustion boiler body 3 through new trend tuber pipe 2 drum by air-blower 1, and the trend of gas loops through wind chamber under the grate in layer combustion boiler body 3, fuel layer surface on the grate, furnace arch export and wing flue, and the flue gas comes out from layer combustion boiler body 3 and gets into economizer 5 through flue 4, then loops through behind multitube dust remover 6, sack cleaner 7, draught fan 8, SOx/NOx control unit 9 and chimney 10 and discharges. Therefore, the boiler flue gas after dust removal is led back through the return air pipe 12 and is sent into the grate-fired boiler body 3 to participate in reburning, and the boiler flue gas has low oxygen content and certain temperature and can play a combustion supporting role after being sent to a fire grate through the blower 1, because the low-oxygen environment can enable the flame temperature to be more uniform, the coal coking is reduced, and the fuel burning is more sufficient; excessive low-temperature air heating is avoided, and fuel is saved; in the reburning process, because the low-oxygen environment reduces the generation of nitrogen oxides, part of CO2 can be reduced into CO to play a role in supporting combustion, increasing the heat efficiency and reducing the heat loss. Therefore, the excess air coefficient of the boiler is reduced, the generation of nitrogen oxides of the boiler is inhibited, the emission of smoke is reduced, and the heat production efficiency of the boiler is improved

In a specific embodiment of the present invention, as shown in fig. 1 and fig. 2, the return air duct 12 is provided with an adjustable damper 14 for adjusting the return air volume of the combustion-supporting return air, the adjustable damper 14 specifically adopts a gate valve, a butterfly valve or a multi-blade adjusting valve, and the adjustable damper 14 is located at the end 11 of the return air inlet of the return air duct 12. Through the arrangement of the adjustable windshield 14, the air return quantity can be controlled according to the boiler load and the excess air coefficient of the boiler flue gas, so that the grate-firing coal-fired boiler system achieves low emission and high efficiency.

In a specific embodiment of the present invention, as shown in fig. 1 and 2, the return air pipe 12 is provided with a temperature sensor 15 for measuring the temperature of the combustion-supporting return air, and the temperature sensor 15 is installed inside the return air pipe 12 and at the end of the return air inlet 11. Through the arrangement of the temperature sensor 15, the temperature of the return air introduced by the return air induced draft port 11 can be monitored conveniently, corresponding adjustment work is carried out, and the efficient operation of the improved layer combustion coal-fired boiler system is achieved.

In a specific embodiment of the present invention, as shown in fig. 1 and 2, the outer wall of the return air pipe 12 is coated with a heat insulating layer and a protective layer. The heat preservation can adopt insulation materials such as polyurethane expanded material or rock wool, the inoxidizing coating specifically adopts the sheet steel edge rolling to cup joint and lays, prevents that the heat preservation from receiving the damage. Meanwhile, a corresponding waterproof layer can be arranged to prevent moisture from permeating and reducing the heat preservation effect of the heat preservation layer. When the combustion-supporting return air is conveyed by the return air pipe 12, the heat dissipation loss is reduced, the high-temperature recycling of the combustion-supporting return air is ensured, the heat energy utilization is improved, and the efficiency of the layer combustion coal-fired boiler system is further improved.

The utility model discloses a combustion-supporting device of layer combustion boiler return air, the boiler flue gas after leading back the dust removal through return air pipe 12 sends into layer combustion boiler body 3 and participates in the reburning, because of the low oxygen content of boiler flue gas and have certain temperature to send to the grate through air-blower 1 and can play the combustion-supporting effect, the low oxygen environment can make flame temperature more even, has reduced the coal-fired coking, the fuel burning is more abundant; excessive low-temperature air heating is avoided, and fuel is saved; in the reburning process, because the low-oxygen environment reduces the generation of nitrogen oxides, part of CO2 can be reduced into CO to play a role in supporting combustion, increasing the heat efficiency and reducing the heat loss. In addition, through the arrangement of the adjustable windshield 14, the air return quantity can be controlled according to the boiler load and the excess air coefficient of the boiler flue gas, so that the grate-fired coal-fired boiler system achieves low emission and high efficiency; the over-temperature sensor 15 is arranged, so that the temperature of the return air introduced by the return air induction port 11 can be conveniently monitored, corresponding adjustment work is carried out, and the high-efficiency operation of the improved layer combustion coal-fired boiler system is achieved; the heat preservation and the protective layer can reduce heat dissipation loss when the return air pipe 12 conveys the combustion-supporting return air, ensure high-temperature recycling of the combustion-supporting return air, improve heat energy utilization and further improve the efficiency of the layer combustion coal-fired boiler system.

The above-mentioned embodiments are only intended to describe the preferred embodiments of the present invention, but not to limit the scope of the present invention, and those skilled in the art should also be able to make various modifications and improvements to the technical solution of the present invention without departing from the spirit of the present invention, and all such modifications and improvements are intended to fall within the scope of the present invention as defined in the appended claims.

Claims

1. The utility model provides a combustion-supporting device of layer combustion boiler return air for on layer combustion coal fired boiler system, its characterized in that: including return air pipe (12) that are used for carrying combustion-supporting return air, return air inlet (11) of return air pipe (12) set up in the exit of boiler system's draught fan (8), return air outlet (13) of return air pipe (12) set up in the air intake department of boiler system's air-blower (1), air-blower (1) is with the combustion-supporting return air that return air pipe (12) sent back and is bloated again boiler system's layer fires boiler body (3) and participates in the reburning.

2. The layered combustion boiler return air combustion supporting device of claim 1, characterized in that: the air return pipe (12) is provided with an adjustable damper (14) for adjusting the return air quantity of the combustion-supporting return air, and the adjustable damper (14) is positioned at the end of the return air inlet (11) of the air return pipe (12).

3. The layered combustion boiler return air combustion supporting device of claim 1, characterized in that: and a temperature sensor (15) for measuring the temperature of the combustion-supporting return air is arranged on the return air pipe (12), and the temperature sensor (15) is arranged in the return air pipe (12) and at the end of the return air suction opening (11).

4. The layered combustion boiler return air combustion supporting device of claim 1, characterized in that: and the periphery of the outer wall of the air return pipe (12) is coated with a heat preservation layer and a protective layer.