CN203222484U - Circulating fluidized bed boiler structure for extracting selenium from stone coal - Google Patents

Abstract

A circulating fluidized bed boiler structure for selenium extraction from stone coal, including a circulating fluidized bed boiler, a connection between the flue gas output of the circulating fluidized bed boiler and the high-temperature dedusting equipment, and the input connection between the high-temperature dedusting equipment and the air preheater , the air inlet of the air preheater is connected to the cold air, the hot air outlet of the air preheater is connected to the air inlet of the circulating fluidized bed boiler, and the flue gas output of the air preheater passes through the low-temperature dust removal equipment and the flue gas subsequent treatment Equipment connection, the connection between the ash outlet of the low-temperature dedusting equipment and the selenium extraction system, the flue gas pipeline between the high-temperature dedusting equipment and the air preheater, or the flue gas pipe between the circulating fluidized bed boiler and the high-temperature dedusting equipment At least one place on the road is equipped with an economizer, the water inlet of the economizer is connected to the boiler feed water, and the water outlet of the economizer is connected to the water inlet of the circulating fluidized bed boiler. This structure greatly increases the selenium content in the fly ash entering the selenium extraction system , reduce the amount of fly ash entering the selenium extraction system, reduce the investment in the selenium extraction system and the cost of selenium extraction.

Description

A circulating fluidized bed boiler structure for selenium extraction from stone coal

technical field

The utility model relates to the technical fields of thermal equipment and metallurgy, in particular to a circulating fluidized bed boiler structure for selenium extraction from stone coal.

Background technique

Stone coal is a kind of polymetallic paragenetic shale mine, which is widely distributed in my country. Stone coal can be used as a low-quality fuel, and a variety of rare metals can also be extracted from it. According to the content of various metals in stone coal in various places, elements such as vanadium and selenium can be extracted. The main associated mineral of stone coal in Enshi, Hubei, my country is selenium, with a content of 0.0275%, which meets the grade requirements for comprehensive utilization of associated mineral resources, and has great value in resource exploitation and utilization.

If selenium is directly extracted from coal-fired flue gas and fly ash, due to the low calorific value of stone coal and high ash content, the amount of flue gas produced by combustion is large, and the amount of ash produced by combustion is large, so that the content of selenium in flue gas and ash is low , so that the follow-up selenium extraction system requires a huge investment.

Contents of the invention

In order to overcome the shortcomings of the above-mentioned prior art, the purpose of this utility model is to provide a circulating fluidized bed boiler structure for selenium extraction from stone coal, which can greatly increase the selenium content in the fly ash entering the selenium extraction system and reduce the amount of selenium entering the selenium extraction system. The amount of fly ash can reduce the investment in selenium extraction system and the cost of selenium extraction.

In order to achieve the above object, the utility model is realized through the following technical solutions:

A circulating fluidized bed boiler structure for selenium extraction from stone coal, comprising a circulating fluidized bed boiler 1, the input of the circulating fluidized bed boiler 1 and the pipe connection for coal feeding, the slag output and the removal of the circulating fluidized bed boiler 1 Slag system 6 connection, flue gas output of circulating fluidized bed boiler 1 and input connection of high temperature dedusting equipment 2, flue gas output of high temperature dedusting equipment 2 and input connection of air preheater 3, ash outlet of high temperature dedusting equipment 2 It is connected to the ash removal system 7, the air inlet of the air preheater 3 is connected to the cold air, the hot air outlet of the air preheater 3 is connected to the air inlet of the circulating fluidized bed boiler 1, and the flue gas of the air preheater 3 The output is connected to the flue gas follow-up processing equipment 5 through the low-temperature dust removal equipment 4, and the ash outlet of the low-temperature dust removal equipment 4 is connected to the selenium extraction system 8;

On the flue gas pipeline between the high-temperature dedusting equipment 2 and the air preheater 3, or at least one of the flue gas pipelines between the circulating fluidized bed boiler 1 and the high-temperature dedusting equipment 2 is provided with an economizer 9, saving The water inlet of the coal device 9 is connected to the boiler feed water, and the water outlet of the economizer 9 is connected to the water inlet of the circulating fluidized bed boiler 1.

The high-temperature dust removal equipment 2 adopts a high-temperature electric dust collector 10 and a high-temperature cyclone dust collector 11, and is arranged in a high-temperature area where the flue gas temperature is higher than 315°C, so that the fly ash separated by the high-temperature dust collector does not contain selenium dioxide.

The low-temperature dust removal equipment 4 adopts an electric dust collector 12 , a bag filter 13 or an electric bag dust collector 14 , and the selenium dioxide desublimates in the fly ash separated in the low-temperature dust removal equipment 4 .

The utility model mainly utilizes the principle of sublimation of selenium dioxide at 315 DEG C to increase the selenium content in the fly ash entering the selenium extraction system. The specific process is as follows. After the burning of selenium-containing stone coal, a large amount of flue gas is produced, and selenium is oxidized into selenium dioxide. When the flue gas temperature is higher than 315°C, the selenium dioxide in the flue gas is in a gaseous state. In this state, the flue gas is subjected to high-temperature dust removal, and the fly ash removed by the high-temperature dust removal equipment does not contain selenium dioxide. Then arrange the heating surface in the downstream flue to cool the flue gas. When the temperature of the flue gas is lower than 315°C, selenium dioxide desublimes on the low-temperature fly ash. The low-temperature dust removal equipment is used to separate the fly ash in the flue gas, and the separated low-temperature fly ash with high selenium content enters the selenium extraction system to extract selenium.

The concentration of selenium in low temperature fly ash is related to the efficiency of high temperature dust removal equipment. The higher the efficiency of the high-temperature dust removal equipment, the less the amount of fly ash in the flue gas after dust removal. While the content of selenium dioxide in flue gas remains unchanged at high temperature, these selenium dioxide sublimes in a small amount of fly ash at low temperature, thus increasing the selenium content of fly ash entering the selenium extraction system.

The utility model also combines the feature that the circulating fluidized bed boiler can burn low calorific value stone coal with the selenium extraction system of the stone coal. It can not only utilize the heat of stone coal, but also efficiently extract selenium from stone coal. The ash under high temperature dust removal can also be used as building materials, realizing the comprehensive utilization of stone coal resources.

The utility model can also determine the quality of the fuel coal entering the boiler according to the calorific value of the stone coal. For stone coal with too low calorific value, fuel with higher calorific value can be blended, and for stone coal with higher calorific value, it can be fed into the boiler separately.

The utility model utilizes the characteristic that selenium dioxide in the high-temperature flue gas is in a gaseous state, and pre-dedusts the flue gas at a high temperature, so that the ash removed in the high-temperature state does not contain selenium, and the selenium dioxide is sublimated and enriched at high temperature. In the fly ash separated by the low-temperature dust collector downstream of the dust collector, the enrichment concentration of selenium dioxide in the fly ash is greatly increased, and the cost of selenium extraction is significantly reduced. The concentration of selenium in the fly ash separated by the low temperature dust collector is related to the dust removal efficiency of the high temperature dust collector. If the dust collector efficiency of the high temperature dust collector reaches 90%, the selenium content of the fly ash separated from the low temperature dust collector will increase by 10 times, and the cost of the selenium extraction system will be reduced by more than 50%. When the efficiency of the high-temperature dust collector reaches 99.9%, the concentration of selenium in the fly ash separated from the low-temperature dust collector will increase by 100 times, and the cost of the selenium extraction system will be reduced by more than 90%.

Description of drawings

Fig. 1 is the structural representation of embodiment 1.

Fig. 2 is the structural representation of embodiment 2.

Figure 3 is a schematic structural view of Embodiment 3.

FIG. 4 is a schematic structural view of Embodiment 4.

Figure 5 is a schematic structural view of Embodiment 5.

Detailed ways

The utility model is described in detail below in conjunction with the embodiments, and the following examples are used to illustrate the utility model, but those skilled in the art understand that all embodiments are not intended to limit the utility model. Any improvements or changes made within the scope of the utility model are within the protection scope of the utility model.

Example 1

As shown in Figure 1, a circulating fluidized bed boiler structure for selenium extraction from stone coal, including circulating fluidized bed boiler 1, the input of circulating fluidized bed boiler 1 and the pipeline connection of coal feeding, circulating fluidized bed boiler The slag output of 1 is connected to the slag removal system 6, the flue gas output of the circulating fluidized bed boiler 1 is connected to the input of the high-temperature dust removal equipment 2, the flue gas output of the high-temperature dust removal equipment 2 is connected to the input of the air preheater 3, and the high-temperature dust removal The ash outlet of the equipment 2 is connected to the ash removal system 7, the air inlet of the air preheater 3 is connected to the cold air, the hot air outlet of the air preheater 3 is connected to the air inlet of the circulating fluidized bed boiler 1, and the air preheater The flue gas output of the heater 3 is connected to the flue gas subsequent processing equipment 5 through the low-temperature dust removal device 4, and the ash outlet of the low-temperature dust removal device 4 is connected to the selenium extraction system 8;

An economizer 9 is arranged on the flue gas pipeline between the high temperature dedusting equipment 2 and the air preheater 3, the water inlet of the economizer 9 is connected to the boiler feed water, the water outlet of the economizer 9 is connected to the circulating fluidized bed boiler 1 water inlet connection.

The working principle of this embodiment is:

Stone coal fuel enters the circulating fluidized bed boiler 1 as coal feed for combustion, and the large particle bottom slag produced by the combustion is discharged through the slag removal system 6 matched with the boiler; the flue gas produced by combustion enters the high-temperature dust removal equipment 2, and the separation of the high-temperature dust removal equipment 2 The fly ash that comes down enters the ash removal system 7, and the flue gas cools down through the heating surface of the economizer 9 arranged in the flue. The cooling medium in the heating surface of the economizer 9 is boiler feed water, and the heated feed water enters the circulating fluidization Bed Boiler1. The flue gas cooled by the economizer 9 enters the air preheater 3, and the air in the air preheater 3 is used for boiler combustion. The air is heated by the flue gas and enters the circulating fluidized bed boiler 1, and the flue gas is preheated by the air. After the device 3 is cooled, it enters the low-temperature dedusting equipment 4, and the fly ash separated by the low-temperature dedusting equipment 4 enters the selenium extraction system 8, and the flue gas passing through the low-temperature dedusting equipment 4 enters the subsequent processing equipment 5.

Example 2

As shown in Figure 2, on the basis of Example 1, the high-temperature dust removal equipment 2 adopts a high-temperature electric precipitator 10, and is arranged in a high-temperature area where the flue gas temperature is higher than 315°C, so that the high temperature is not enough for the fly ash separated by the dust collector. Contains selenium dioxide; the low-temperature dust removal equipment 4 uses an electric dust collector 12, and the selenium dioxide desublimates in the fly ash separated in the electric dust collector 12.

Example 3

As shown in Figure 3, on the basis of Example 1, an economizer 9 is provided on the flue gas pipeline between the circulating fluidized bed boiler 1 and the high-temperature dedusting equipment 2, and the water inlet of the economizer 9 is connected to the boiler feed water , the water outlet of the economizer 9 is connected to the water inlet of the circulating fluidized bed boiler 1; the high-temperature dust removal equipment 2 adopts a high-temperature electrostatic precipitator 10, and is arranged in a high-temperature area where the flue gas temperature is higher than 315°C, so that the high temperature is separated by the dust collector The fly ash under the dust does not contain selenium dioxide; the low temperature dust removal equipment 4 adopts the bag filter 13, and the selenium dioxide desublimates in the fly ash separated in the bag filter 13.

Example 4

Referring to Fig. 4, on the basis of embodiment 1, the economizer 9 on the flue gas pipeline between the high-temperature dedusting equipment 2 and the air preheater 3 is removed, and the circulating fluidized bed boiler 1 and the high-temperature dedusting equipment 2 There is an economizer 9 on the flue gas pipeline between them, the water inlet of the economizer 9 is connected to the boiler feed water, the water outlet of the economizer 9 is connected to the water inlet of the circulating fluidized bed boiler 1; the high temperature dust removal equipment 2 adopts a high temperature electric The dust collector 10 is arranged in a high-temperature area where the flue gas temperature is higher than 315°C, so that the fly ash separated by the dust collector at high temperature does not contain selenium dioxide; the low-temperature dust removal equipment 4 uses an electric bag filter 14, and the selenium dioxide desublimates In the fly ash separated in the electric bag filter 14.

Example 5

Referring to Figure 5, on the basis of Example 1, an economizer 9 is provided on the flue gas pipeline between the circulating fluidized bed boiler 1 and the high-temperature dedusting equipment 2, and the water inlet of the economizer 9 is connected to the boiler feed water , the water outlet of the economizer 9 is connected to the water inlet of the circulating fluidized bed boiler 1; the high-temperature dust removal equipment 2 adopts a high-temperature cyclone dust collector 11, and is arranged in a high-temperature area where the flue gas temperature is higher than 315°C, so that the high temperature is separated by the dust collector The fly ash under the dust does not contain selenium dioxide; the low temperature dust removal equipment 4 adopts the bag filter 13, and the selenium dioxide desublimates in the fly ash separated in the bag filter 13.

Claims (3)

1. A circulating fluidized bed boiler structure for selenium extraction from stone coal, comprising a circulating fluidized bed boiler (1), characterized in that: the input of the circulating fluidized bed boiler (1) is connected to the coal feeding pipeline, and the circulation The slag output of the fluidized bed boiler (1) is connected to the slag removal system (6), the flue gas output of the circulating fluidized bed boiler (1) is connected to the input of the high temperature dust removal equipment (2), and the flue gas output of the high temperature dust removal equipment (2) The air output is connected to the input of the air preheater (3), the ash outlet of the high temperature dust removal equipment (2) is connected to the ash removal system (7), the air inlet of the air preheater (3) is connected to the cold air, and the air preheater The hot air outlet of the heater (3) is connected to the air inlet of the circulating fluidized bed boiler (1), and the flue gas output of the air preheater (3) passes through the low-temperature dust removal equipment (4) and the flue gas subsequent treatment equipment (5 ) connection, the ash outlet of the low temperature dust removal equipment (4) is connected to the selenium extraction system (8); On the flue gas pipeline between the high temperature dedusting equipment (2) and the air preheater (3), or at least one place on the flue gas pipeline between the circulating fluidized bed boiler (1) and the high temperature dedusting equipment (2) An economizer (9) is provided, the water inlet of the economizer (9) is connected to the boiler feed water, and the water outlet of the economizer (9) is connected to the water inlet of the circulating fluidized bed boiler (1). 2. The structure according to claim 1, characterized in that: the high-temperature dust removal equipment (2) adopts a high-temperature electrostatic precipitator (10) or a high-temperature cyclone dust collector (11), and is arranged where the flue gas temperature is higher than 315°C The high temperature area, so that the fly ash separated by the high temperature does not contain selenium dioxide. 3. The structure according to claim 1, characterized in that: the low-temperature dust removal equipment (4) adopts an electric dust collector (12), a bag filter (13) or an electric bag filter (14), and selenium dioxide Desublimation is in the fly ash separated in the low temperature dedusting equipment (4).

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