CN211176771U

CN211176771U - Device for using magnesium slag as desulfurizer in fluidized bed boiler

Info

Publication number: CN211176771U
Application number: CN201922204154.3U
Authority: CN
Inventors: 茹宇; 王海涛; 时正海; 高洪培
Original assignee: Huaneng Clean Energy Research Institute
Current assignee: Huaneng Clean Energy Research Institute
Priority date: 2019-12-09
Filing date: 2019-12-09
Publication date: 2020-08-04
Anticipated expiration: 2029-12-09

Abstract

The utility model discloses a device for utilizing magnesium slag as a desulfurizer in a fluidized bed boiler, which comprises a boiler, a magnesium slag bin, a flue gas recirculation fan and a Venturi mixer; the flue set up in the afterbody of boiler, the circulation tuber pipe has been drawn forth in the flue, the circulation tuber pipe communicate in the slag notch of boiler, flue gas recirculation fan set up in on the circulation tuber pipe and be located on the circulation tuber pipe flue gas recirculation fan's low reaches position still is provided with the venturi mixer, the magnesium sediment feed bin communicates in being located through the pipeline the powder entry of venturi mixer throat. By adopting the technical scheme, the recycling of the circulating flue gas in the fluidized bed boiler device can be realized, and the problem of unstable bed temperature caused by too low temperature of the desulfurizer is avoided.

Description

Device for using magnesium slag as desulfurizer in fluidized bed boiler

Technical Field

The utility model relates to an utilize device of magnesium sediment as desulfurizer in fluidized bed boiler stove belongs to fluidized bed boiler technical field.

Background

China is a big coal country, the utilization of coal resources is very common, but along with the increase of environmental protection pressure, the clean and efficient utilization of the coal resources is particularly important. The circulating fluidized bed boiler has the advantages of wide fuel adaptability, good load regulation, high combustion efficiency, capability of realizing high-efficiency comprehensive utilization of resources, low pollutant emission intensity and the like, and is widely applied at home and abroad at present as clean coal combustion equipment. Coal contains sulfur and thus releases SO when burned₂Due to SO₂Venting to the atmosphere is a significant hazard and therefore emission concentrations must be controlled during combustion. The fluidized bed boiler mainly controls SO by adding purchased limestone powder into a conveying and feeding system of a hearth and a method for adding limestone particles into the boiler₂And (5) discharging. In order to ensure the desulfurization efficiency in the operation process of the fluidized bed boiler, the Ca/S ratio is controlled to be more than 1.5-2.0 by the requirement, the amount of limestone actually required after the operation for a long time is large, and the problem of high desulfurization cost exists. Chinese patent document CN101703886A discloses a desulfurization method for a circulating fluidized bed boiler by directly using magnesium slag, which can realize desulfurization in a coal burning process by using the characteristics of magnesium slag and special combustion conditions of the circulating fluidized bed. For another example, chinese patent document CN101791622A discloses a process for converting magnesium metal slag into boiler desulfurizer, which treats the waste slag from magnesium metal smelting into desulfurizer for circulating fluidized bed boiler. However, in the process of using magnesium slag as a boiler desulfurizer in the prior art, an independent magnesium slag feeding system needs to be added, and in addition, the temperature of the magnesium slag added into the boiler is too low, which easily causes unstable bed temperature.

SUMMERY OF THE UTILITY MODEL

Therefore, the utility model aims to solve the technical problem that the temperature of the magnesium slag is too low in adding complicated magnesium slag feeding system and adding the boiler among the prior art, and provide an utilize the device of magnesium slag as desulfurizer in the fluidized bed boiler.

In order to realize the aim, the device for utilizing the magnesium slag as the desulfurizer in the fluidized bed boiler comprises a boiler, a magnesium slag bin, a flue gas recirculation fan and a venturi mixer; the flue set up in the afterbody of boiler, the circulation tuber pipe has been drawn forth in the flue, the circulation tuber pipe communicate in the slag notch of boiler, flue gas recirculation fan set up in on the circulation tuber pipe and be located on the circulation tuber pipe flue gas recirculation fan's low reaches position still is provided with the venturi mixer, the magnesium sediment feed bin communicates in being located through the pipeline the powder entry of venturi mixer throat.

And a powder feeder is also arranged on a pipeline of the magnesium slag bin communicated with the Venturi mixer.

The slag spout is arranged 3-4 m above an air distribution plate of the boiler.

And a pressure regulating valve is arranged in front of a gas inlet of the Venturi mixer.

And the outlet of the air preheater is communicated with an air distribution plate at the bottom of the boiler.

And an air preheater is arranged in the flue and connected to the primary cooling fan for preheating primary cooling air blown by the primary cooling fan.

Adopt above-mentioned technical scheme, the utility model discloses an utilize device of magnesium sediment as desulfurizer in fluidized bed boiler stove, compare with prior art, have following beneficial effect:

1. by specifically designing a spraying port of the magnesium-containing waste residue additive in the fluidized bed boiler, the magnesium-containing waste residue is used for replacing limestone powder to carry out desulfurization in the fluidized bed boiler, so that the consumption of the limestone is reduced, and the desulfurization cost is saved for a power plant;

2. the circulating air pipe led out from the boiler tail flue is directly utilized, the flue gas recirculation fan and the Venturi mixer are arranged, and the circulating flue gas of the tail flue is used as power to realize effective injection of magnesium-containing waste residues, so that the recycling of the circulating flue gas in the fluidized bed boiler device is realized, and the problem of unstable bed temperature caused by too low temperature of a desulfurizer is solved; the whole device does not need to greatly change the structure of the original boiler, has low cost and is easy for industrialized production.

Drawings

FIG. 1 is a schematic structural view of the device for using magnesium slag as a desulfurizing agent in a fluidized bed boiler of the present invention.

In the figure: 1. a boiler; 2. a magnesium slag bin; 3. a circulating air duct; 4. a flue gas recirculation fan; 5. a venturi mixer; 6. a powder feeder; 7. a pressure regulating valve; 8. a slag spraying port; 9. a wind distribution plate; 10. a separator; 11. a material returning device; 12. a flue; 13. a dust removal device; 14. a chimney; 15. a coal hopper; 16. a coal feeder; 17. a coal crusher; 18. an air preheater; 19. a primary cooling fan.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, the utility model provides an utilize device of magnesium sediment as desulfurizer in fluidized bed boiler 1 stove sets gradually flue 12, dust collecting equipment 13 and chimney 14 at boiler 1's afterbody, circulation tuber pipe 3 has been drawn forth in the flue 12, circulation tuber pipe 3 communicate in boiler 1's slag spout 8, slag spout 8 sets up in 3 ~ 4m departments in boiler 1's grid 9 top. A flue gas recirculation fan 4 and a venturi mixer 5 are sequentially arranged on the circulating air pipe 3.

Magnesium-containing waste residues are arranged in the magnesium residue bin 2, the mass fraction of magnesium oxide in the magnesium-containing waste residues is more than or equal to 55%, the particle sizes of carbide residues and magnesium-containing waste residue particles are 100-150 meshes, and the magnesium-containing waste residues can be ethyl maltol magnesium-containing waste residues as the optimization. The magnesium slag bin 2 is communicated with a powder inlet at the throat part of the Venturi mixer 5 through a pipeline.

An air preheater 18 is arranged in the flue 12 and used for exchanging heat between the pumped cold air and the high-temperature flue gas, a primary cold air fan 19 is arranged at a cooling air inlet of the air preheater 18, and the air heated by the high-temperature flue gas is introduced into the boiler 1 from the air distribution plate 9 and used for preheating the primary cold air fed into the boiler 1. Raw coal is fed into the boiler 1 from a coal hopper 15 through a coal feeder 16 and a coal breaker 17 for combustion; a dust remover and a chimney 14 are arranged behind a tail flue 12 of the boiler 1 and used for discharging low-temperature flue gas after dust removal.

Through the structure, the magnesium slag bin 2 is communicated with the venturi mixer 5, and a powder feeder 6 is further arranged on the pipeline. Magnesium sediment feed bin 2 is connected to 5 powder entrances of venturi mixer through powder feeder 6, 5 gas entrances of venturi mixer link to each other with 4 air outlet pipeline of flue gas recirculation fan, magnesium-containing waste residue powder mixes the powder air current in venturi mixer 5 from the recirculated flue gas that magnesium sediment feed bin 2 carried through powder feeder 6 and flue gas recirculation fan 4, discharge and spout into boiler 1 through spouting sediment mouth 8 from 5 discharge ports of venturi mixer, the speed of spouting of magnesium-containing waste residue sets up to 20 ~ 30 m/s.

A pressure regulating valve 7 is arranged in front of a gas inlet of the Venturi mixer 5 and used for regulating the pressure of recirculated flue gas conveyed by the flue gas recirculation fan 4 to 2-3 KPa, and then the recirculated flue gas is mixed with magnesium-containing waste residue powder, the temperature of hot flue gas is above 150 ℃, waste residue heating is facilitated, and unstable temperature of a hearth caused by too low temperature after entering the hearth is prevented; the temperature of the cold primary air is 20-30 ℃, and the low-temperature air is favorable for preventing the magnesium-containing waste residue from sintering; meanwhile, the slag spout 8 is positioned in a relatively lower area of the boiler 1, SO that the waste slag can stay in the boiler for a longer time, and the magnesium-containing waste slag enters the boiler 1 and then reacts with SO in the flue gas₂Fully react to form magnesium sulfate and other substances, and reduce SO in flue gas₂And (4) concentration.

The reaction mechanism of the magnesium-containing waste residue with the main component of magnesium oxide to carry out desulfurization at high temperature is as follows:

2MgO+2SO₂+O₂→2MgSO₄

it should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications can be made without departing from the scope of the invention.

Claims

1. A device for using magnesium slag as desulfurizer in a fluidized bed boiler is characterized in that: comprises a boiler, a magnesium slag bin, a flue gas recirculation fan and a Venturi mixer; the flue set up in the afterbody of boiler, the circulation tuber pipe has been drawn forth in the flue, the circulation tuber pipe communicate in the slag notch of boiler, flue gas recirculation fan set up in on the circulation tuber pipe and be located on the circulation tuber pipe flue gas recirculation fan's low reaches position still is provided with the venturi mixer, the magnesium sediment feed bin communicates in being located through the pipeline the powder entry of venturi mixer throat.

2. The apparatus for using magnesium slag as desulfurizing agent in a fluidized bed boiler according to claim 1, wherein: and a powder feeder is also arranged on a pipeline of the magnesium slag bin communicated with the Venturi mixer.

3. The apparatus for using magnesium slag as desulfurizing agent in a fluidized bed boiler according to claim 1, wherein: the slag spout is arranged 3-4 m above an air distribution plate of the boiler.

4. The apparatus for using magnesium slag as desulfurizing agent in a fluidized bed boiler according to claim 1, wherein: and a pressure regulating valve is arranged in front of a gas inlet of the Venturi mixer.

5. The apparatus for using magnesium slag as desulfurizing agent in a fluidized bed boiler according to claim 1, wherein: and an air preheater is arranged in the flue and connected to the primary cooling fan for preheating the primary cooling air blown by the primary cooling fan.

6. The apparatus for using magnesium slag as desulfurizing agent in a fluidized bed boiler as defined in claim 5, wherein: the outlet of the air preheater is communicated with an air distribution plate at the bottom of the boiler.