阅读说明：本技术 一种锅炉结构及锅炉炉内脱硫脱硝方法 (Boiler structure and in-boiler desulfurization and denitrification method ) 是由 郭强 于 2019-10-29 设计创作，主要内容包括：本发明涉及锅炉设备技术领域,公开了一种锅炉结构及锅炉炉内脱硫脱硝方法,包括竖直安装的炉膛以及尾部烟道,在所述炉膛的顶部侧壁上间隔设置第一喷嘴和第二喷嘴,所述第一喷嘴用于向所述炉膛内部喷入钙粉,所述第二喷嘴用于向所述炉膛内部喷入氨水或尿素。本发明提供的一种锅炉结构及锅炉炉内脱硫脱硝方法,通过向炉膛适当区域喷入钙粉,钙粉可与烟气中的酸性物质发生反应,通过酸碱中和与氧化还原,可实现炉内脱硫；通过向炉膛适当区域喷入氨水或尿素,可实现炉内SNCR脱硝；该层燃锅炉结构可无需在炉膛外部设置脱硫脱硝装置,可降低环保投入,减小锅炉占地,提高经济性。(The invention relates to the technical field of boiler equipment, and discloses a boiler structure and a desulfurization and denitrification method in a boiler, which comprise a vertically-installed hearth and a tail flue, wherein a first nozzle and a second nozzle are arranged on the side wall of the top of the hearth at intervals, the first nozzle is used for spraying calcium powder into the hearth, and the second nozzle is used for spraying ammonia water or urea into the hearth. According to the boiler structure and the in-boiler desulfurization and denitrification method, calcium powder is sprayed into a proper area of a hearth, the calcium powder can react with acidic substances in flue gas, and the in-boiler desulfurization can be realized through acid-base neutralization and oxidation reduction; the SNCR denitration in the furnace can be realized by spraying ammonia water or urea into a proper area of the hearth; this layer fires boiler structure can need not to set up SOx/NOx control device in the furnace outside, can reduce the environmental protection and drop into, reduces the boiler and takes up an area of, improves economic nature.)

1. A boiler structure comprises a vertically-installed hearth and a tail flue, and is characterized in that a first nozzle and a second nozzle are arranged on the side wall of the top of the hearth at intervals, the first nozzle is used for spraying calcium powder into the hearth, and the second nozzle is used for spraying ammonia water or urea into the hearth; wherein the calcium powder comprises calcium carbonate powder or calcium oxide powder.

2. The boiler structure according to claim 1, wherein the furnace comprises a main furnace and an auxiliary furnace, the auxiliary furnace is arranged at the rear part of the main furnace side by side, the rear part of the auxiliary furnace is provided with convection channels side by side, the top end of the main furnace is communicated with the top end of the auxiliary furnace, the bottom end of the auxiliary furnace is communicated with the bottom end of the convection channel, and the top end of the convection channel is communicated with a tail flue.

3. The boiler structure according to claim 2, wherein the first nozzles are provided at the top of the side wall of the main furnace, and the first nozzles are provided toward the top inlet of the sub-furnace; the second nozzle is arranged at the top of the side wall of the auxiliary hearth and is positioned at a position corresponding to the position of the top inlet of the auxiliary hearth.

4. The boiler structure according to claim 2, wherein a denitration device is provided inside the convection channel at a region where the smoke temperature is 300-350 ℃.

5. The boiler structure according to claim 2, wherein a grate is arranged at the bottom of the main furnace, the grate is covered at the bottom of the main furnace, the cross-sectional areas of the middle part and the top part of the main furnace are smaller than that of the bottom part, the auxiliary furnace is bent, and an adapter part is arranged between the bottom end of the auxiliary furnace and the bottom end of the convection channel.

6. The boiler structure according to claim 2, wherein a convection heating surface is provided inside the convection passage, and an economizer and an air preheater are provided in sequence on the back flue in a flow direction of flue gas.

7. A method for desulfurization and denitrification in a boiler based on the boiler structure according to any one of claims 1 to 6, comprising:

spraying calcium powder into the top end of the interior of the main hearth;

and spraying ammonia water or urea into the top end of the inside of the auxiliary hearth.

8. The method for desulfurization and denitrification in a boiler according to claim 7, wherein the step of injecting calcium powder into the top end of the interior of the main furnace is as follows: calcium powder is sprayed into the areas with the top outlet of the main hearth and the top inlet of the auxiliary hearth and the smoke temperature of 850-950 ℃;

the ammonia water or urea sprayed into the top end of the inner part of the auxiliary hearth is specifically as follows: and ammonia water or urea is sprayed into the region with the smoke temperature of 850-950 ℃ at the inlet of the auxiliary hearth.

9. The method for desulfurization and denitrification in a boiler according to claim 7, wherein calcium powder is injected into the main furnace by compressed air; ammonia water or urea is delivered by a pump and sprayed into the auxiliary hearth in a compressed air atomization mode.

10. The method for desulfurization and denitrification in a boiler according to claim 7, wherein the interval between the injection of calcium powder into the inner top end of the main furnace and the injection of ammonia water or urea into the inner top end of the auxiliary furnace is equal to or longer than a predetermined time; the distance between the spraying area of the calcium powder and the spraying area of the ammonia water or the urea is more than or equal to the preset distance.

Technical Field

The invention relates to the technical field of boiler equipment, in particular to a boiler structure and a desulfurization and denitrification method in a boiler.

Background

China is a developing country taking coal as a main energy source, and the coal resource accounts for about 75% of the total energy production and consumption of China. During the combustion of coal, a large amount of pollutants, among which Nitrogen Oxides (NO), are produced_X) The method has great harm to the environment, and the nitrogen oxide can form photochemical smog to harm human health besides forming acid rain to destroy the ecological environment. High temperature combustion of coal is NO_XOne of the main sources of the coal-fired boiler, and the boiler in China mainly uses the coal as the main source, thereby reducing the NO of the coal-fired boiler_XThe discharge of (b) has important significance.

At present, various technologies and devices have been developed at home and abroad to be applied to desulfurization and denitration of boilers. The denitration technology comprises a low-nitrogen combustion technology, a flue gas denitration (SNCR) technology and the like. The reaction temperature is not controlled in place, and the reaction time is short, so that the reaction amount of nitrogen and carbon particles in the flue gas is small, and the self-separation of nitrogen oxides is not in time, so that the content of nitrogen oxides in the flue gas discharged from the tail part of the boiler is high. Various methods for desulfurizing boilers also have disadvantages.

Most of the currently used coal-fired industrial boilers are provided with desulfurization and denitrification devices, so that the environmental protection investment is large, the occupied area is large, and the economical efficiency is poor.

Disclosure of Invention

Technical problem to be solved

The invention aims to provide a boiler structure and a desulfurization and denitrification method in the boiler, which are used for solving or partially solving the problems that most of the conventional coal-fired industrial boilers are provided with desulfurization and denitrification devices, the environmental protection investment is large, the occupied area is large and the economical efficiency is poor.

(II) technical scheme

In order to solve the technical problems, the invention provides a boiler structure, which comprises a vertically-installed hearth and a tail flue, wherein a first nozzle and a second nozzle are arranged on the side wall of the top of the hearth at intervals, the first nozzle is used for spraying calcium powder into the hearth, and the second nozzle is used for spraying ammonia water or urea into the hearth; wherein the calcium powder comprises calcium carbonate powder or calcium oxide powder.

On the basis of the scheme, the hearth comprises a main hearth and an auxiliary hearth, the auxiliary hearths are arranged at the rear part of the main hearth side by side, convection channels are arranged at the rear part of the auxiliary hearths side by side, the top end of the main hearth is communicated with the top end of the auxiliary hearth, the bottom end of the auxiliary hearth is communicated with the bottom end of the convection channels, and the top end of the convection channels is communicated with a tail flue.

On the basis of the scheme, the first nozzle is arranged at the top of the side wall of the main hearth and faces the top inlet of the auxiliary hearth; the second nozzle is arranged at the top of the side wall of the auxiliary hearth and is positioned at a position corresponding to the position of the top inlet of the auxiliary hearth.

On the basis of the scheme, a denitration device is arranged in the convection channel and in the area with the smoke temperature of 300-350 ℃.

On the basis of the scheme, the fire grate is arranged at the bottom of the main hearth, the bottom of the main hearth covers the fire grate, the cross-sectional areas of the middle part and the top of the main hearth are smaller than that of the bottom of the main hearth, the auxiliary hearth is bent, and a switching part is arranged between the bottom end of the auxiliary hearth and the bottom end of the convection channel.

On the basis of the scheme, a convection heating surface is arranged inside the convection channel, and an economizer and an air preheater are sequentially arranged on the tail flue along the flowing direction of flue gas.

In a second aspect of the present invention, a method for removing sulfur and nitrogen in a boiler based on the above boiler structure is provided, which includes: spraying calcium powder into the top end of the interior of the main hearth; and spraying ammonia water or urea into the top end of the inside of the auxiliary hearth.

On the basis of the scheme, the step of spraying calcium powder to the top end inside the main hearth specifically comprises the following steps: calcium powder is sprayed into the areas with the top outlet of the main hearth and the top inlet of the auxiliary hearth and the smoke temperature of 850-950 ℃; the ammonia water or urea sprayed into the top end of the inner part of the auxiliary hearth is specifically as follows: and ammonia water or urea is sprayed into the region with the smoke temperature of 850-950 ℃ at the inlet of the auxiliary hearth.

On the basis of the scheme, the calcium powder is injected into the main hearth by adopting compressed air; ammonia water or urea is delivered by a pump and sprayed into the auxiliary hearth in a compressed air atomization mode.

On the basis of the scheme, the interval time between the spraying of the calcium powder to the top end inside the main hearth and the spraying of the ammonia water or the urea to the top end inside the auxiliary hearth is more than or equal to the preset time; the distance between the spraying area of the calcium powder and the spraying area of the ammonia water or the urea is more than or equal to the preset distance.

(III) advantageous effects

According to the boiler structure and the in-boiler desulfurization and denitrification method, calcium powder is sprayed into a proper area of a hearth, the calcium powder can react with acidic substances in flue gas, and the in-boiler desulfurization can be realized through acid-base neutralization and oxidation reduction; the SNCR denitration in the furnace can be realized by spraying ammonia water or urea into a proper area of the hearth; this layer fires boiler structure can need not to set up SOx/NOx control device in the furnace outside, can reduce the environmental protection and drop into, reduces the boiler and takes up an area of, improves economic nature.

Drawings

FIG. 1 is a first schematic view of a boiler configuration according to an embodiment of the present invention;

fig. 2 is a second schematic view of a boiler structure according to an embodiment of the present invention.

Description of reference numerals:

1-a drum;	2-main furnace chamber;	3, a grate;
			4, an auxiliary hearth;	5-convection heating surface;	6-tail flue;
7-a coal economizer;	8-air preheater;	9 — a first nozzle;
			10-a second nozzle;	11-a denitrator;	12-a convection channel;
13-a transfer section.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The embodiment of the invention provides a boiler structure, and with reference to fig. 1, the boiler structure comprises a vertically-installed hearth and a tail flue 6, wherein a first nozzle 9 and a second nozzle 10 are arranged on the side wall of the top of the hearth at intervals, the first nozzle 9 is used for spraying calcium oxide powder or calcium carbonate powder into the hearth, and the second nozzle 10 is used for spraying ammonia water or urea into the hearth.

Calcium oxide powder or calcium carbonate powder is sprayed into a proper area of a hearth, the calcium powder can react with acidic substances in smoke, and the in-furnace desulfurization can be realized through acid-base neutralization and oxidation reduction. By spraying ammonia water or urea into a proper area of the hearth, SNCR denitration in the furnace can be realized. This layer fires boiler structure can need not to set up SOx/NOx control device 11 in the furnace outside, can reduce the environmental protection and drop into, reduces the boiler and takes up an area of, improves economic nature.

Further, the boiler structure is applicable to both the grate-fired boiler shown in fig. 1 and the chain grate boiler shown in fig. 2.

On the basis of the above embodiment, further, furnace includes main furnace 2 and vice furnace 4, vice furnace 4 sets up side by side the rear portion of main furnace 2, the rear portion of vice furnace 4 is equipped with convection current passageway 12 side by side, the top of main furnace 2 with the top of vice furnace 4 is linked together, the bottom of vice furnace 4 with the bottom of convection current passageway 12 is linked together, the top and the afterbody flue 6 of convection current passageway 12 are linked together.

The rear part of the main hearth 2 is the rear side in the flow direction of the flue gas, i.e. the part to which the flue gas flows backwards. The auxiliary furnace 4 and the convection channel 12 are also vertically arranged and are connected with the main furnace 2 in sequence side by side. The layer combustion boiler is additionally provided with an auxiliary hearth 4 and a convection channel 12 at the rear side of a main hearth 2. Flue gas generated by combustion of fuel inside the main furnace 2 flows into the auxiliary furnace 4 through a top outlet, then flows from the top to the bottom of the auxiliary furnace 4 into the convection channel 12, and then flows into the tail flue 6.

According to the layer combustion boiler structure, the auxiliary hearth 4 and the convection channel 12 are sequentially arranged behind the main hearth 2 side by side, the top of the main hearth 2 is communicated with the auxiliary hearth 4, and the bottom of the auxiliary hearth 4 is communicated with the convection channel 12, so that the main hearth 2, the auxiliary hearth 4 and the convection channel 12 form an S-shaped three-return-stroke flue gas channel, the flow distance of flue gas can be effectively increased, the combustion time of fuel, namely pulverized coal, in a boiler is increased, and the combustion efficiency is improved; the products which are not fully combusted in the flue gas are reduced, the emission of sulfur oxides is favorably reduced, the environmental protection investment is reduced, and the economical efficiency is improved.

Furthermore, membrane type water-cooled walls are attached to the peripheral side walls of the main hearth 2 and the auxiliary hearth 4; the side wall of the convection channel 12 is also provided with a membrane water-cooling wall, and a convection heating surface 5 is arranged in the convection channel 12 to improve the use efficiency of heat. The membrane water-cooled wall is communicated with a downcomer which is connected with the boiler barrel 1.

On the basis of the above embodiment, further, the first nozzles 9 are arranged at the top of the side wall of the main furnace 2, and the first nozzles 9 are arranged towards the top inlet of the auxiliary furnace 4; the second nozzles 10 are arranged at the top of the side wall of the auxiliary hearth 4 and are positioned at the position corresponding to the inlet position at the top of the auxiliary hearth 4.

The present embodiment proposes that calcium oxide powder can be injected at the outlet of the main furnace 2 and at the inlet of the auxiliary furnace 4. For the grate-fired boiler, the smoke temperature at the outlet of the main furnace 2 and the inlet of the auxiliary furnace 4 is generally 850-:

CaO+SO₂+1/2O₂→CaSO₄；

CaO＋SO₃→CaSO₄；

furthermore, the calcium oxide powder can be ground to 200 meshes and sprayed into the hearth, which is beneficial to improving the reaction efficiency. The calcium oxide powder can be placed in the storage box, the storage box is connected with the nozzle, and a certain amount of calcium oxide powder is conveyed to the nozzle each time and enters the hearth through air flow injection.

The second nozzle 10 can be arranged towards the central part of the auxiliary hearth 4 and is positioned at the same height with the top inlet of the auxiliary hearth 4, so that the flue gas entering the auxiliary hearth 4 is fully mixed and reacted with ammonia water or urea.

The first nozzle 9 is arranged in the main hearth 2, and the second nozzle 10 is arranged in the auxiliary hearth 4, so that calcium oxide powder and ammonia water or urea react with flue gas in different areas, and the mutual influence of the calcium oxide powder and the ammonia water or the urea can be avoided to reduce the desulfurization and denitrification efficiency; and the smoke passes through the calcium oxide powder and then passes through the ammonia water or the urea, so that the calcium oxide powder can be prevented from moisture absorption and inactivation and corrosion.

On the basis of the above embodiment, further, a denitration device 11 is disposed in the convection channel 12 at the area where the smoke temperature is 300-350 ℃. In the convection channel 12, in the area where the smoke temperature is 300-. The denitration device 11 may be a denitration catalyst (SCR module).

On the basis of the above embodiment, further, the bottom of the main furnace 2 is provided with the grate 3, the bottom of the main furnace 2 covers the grate 3, the cross-sectional areas of the middle part and the top of the main furnace 2 are smaller than the cross-sectional area of the bottom, the auxiliary furnace 4 is bent, and a transition part 13 is arranged between the bottom end of the auxiliary furnace 4 and the bottom end of the convection channel 12.

That is, the fire grate 3 is completely positioned in the main hearth 2, the fire grate 3 has an unchanged structure compared with the original single hearth, the cross sections of the middle part and the top part of the main hearth 2 are reduced so as to reduce the occupied width of the main hearth 2, and the auxiliary hearth 4 and the convection passage 12 are arranged side by side.

The auxiliary hearth 4 and the convection channel 12 are arranged side by side with the top and the middle of the main hearth 2, and the bottom of the auxiliary hearth 4 can be bent to enable the outlet to face one side above the fire grate 3; the convection channel 12 can be arranged with the auxiliary hearth 4 at the top and the middle part, and the bottom can be bent to enable the outlet to face to one side; the outlet at the bottom of the convection channel 12 can be located above the outlet at the bottom of the secondary hearth 4. In order to facilitate the communication between the bottom of the auxiliary hearth 4 and the bottom of the convection channel 12, the adapter part 13 can be arranged to be communicated with the auxiliary hearth and the convection channel 12 respectively, and the flue gas turns at the adapter part 13 and flows into the convection channel 12.

The structure of the arrangement structure can reduce the structural change of the existing boiler grate 3, the auxiliary hearth 4 and the convection channel 12 can be additionally arranged on the basis of the arrangement of the existing grate 3, the combustion efficiency can be improved on the basis of the original fuel combustion amount, and the pollutant emission can be reduced.

Further, the bottom and middle of the main hearth 2 may be bent.

On the basis of the above embodiment, further, a convection heating surface 5 is arranged inside the convection passage 12, and an economizer 7 and an air preheater 8 are sequentially arranged on the tail flue 6 along the flow direction of the flue gas. The heat use efficiency is improved.

On the basis of the foregoing embodiments, further, the present embodiment provides a method for removing sulfur and nitrogen from a boiler based on the structure of the grate-fired boiler described in any of the foregoing embodiments, including: spraying calcium oxide powder into the top end inside the main hearth 2; and ammonia water or urea is sprayed into the top end inside the auxiliary hearth 4.

Calcium oxide powder is sprayed into the hearth, so that in-furnace desulfurization can be realized through acid-base neutralization and redox reaction, the operation is simple and convenient, the environmental protection investment is small, and the economical efficiency is high. By spraying ammonia water or urea into the hearth, denitration in the furnace can be realized.

Because the calcium oxide powder has hygroscopicity, reacts with water to generate alkali, is corrosive and is accompanied with a large amount of heat generation, the calcium oxide powder is firstly sprayed for desulfurization, and then ammonia water or urea is sprayed for denitration, so that the smooth proceeding of desulfurization and denitration is ensured.

On the basis of the above embodiment, further, the step of injecting calcium oxide powder into the top end of the interior of the main hearth 2 specifically includes: calcium oxide powder is sprayed into the areas with the top outlet of the main hearth 2 and the top inlet of the auxiliary hearth 4 and the smoke temperature of 850-950 ℃; the temperature of the area is proper, the mixing reaction of calcium oxide powder is facilitated, and sulfur oxides in the flue gas at the temperature are more, so that the desulfurization effect is improved. Furthermore, the calcium oxide powder can be ground to 200 meshes and injected into the hearth, so that the mixing reaction efficiency can be improved.

The ammonia water or urea sprayed into the top end inside the auxiliary hearth 4 is specifically as follows: and ammonia water or urea is sprayed into the area at the inlet of the auxiliary hearth 4 and with the smoke temperature of 850-950 ℃. The temperature of the area is proper, so that the denitration reaction is favorably carried out.

On the basis of the above embodiment, further, the calcium oxide powder is injected into the main furnace 2 by using compressed air; the ammonia water or urea is delivered by a pump and sprayed into the auxiliary hearth 4 in a compressed air atomization mode. The flow rate of the compressed air for injecting the calcium oxide powder is determined according to the weight of the calcium oxide powder and the type of the pneumatic conveying device for injecting the compressed air; the weight of the calcium oxide powder is determined according to the desulfurization requirement of the boiler. Similarly, the flow rate of the compressed air for injecting the ammonia water or the urea is determined according to the weight of the ammonia water or the urea and the type of the pneumatic conveying device; the weight of the ammonia water or the urea is determined according to the denitration requirement of the boiler.

On the basis of the embodiment, the interval time between the spraying of the calcium oxide powder to the top end inside the main hearth 2 and the spraying of the ammonia water or the urea to the top end inside the auxiliary hearth 4 is longer than or equal to the preset time; the distance between the spraying area of the calcium oxide powder and the spraying area of the ammonia water or the urea is more than or equal to the preset distance. So as to prevent the calcium oxide powder from contacting ammonia water and reacting with the water to generate alkali, so that the nozzle is corroded and the normal desulfurization and denitrification are influenced.

Further, the boiler desulfurization and denitrification method specifically comprises the following steps: CaO powder ground to 200 meshes is sprayed into the areas with the smoke temperature of 850-950 ℃ at the outlet of the main hearth 2 and the inlet of the auxiliary hearth 4 to realize the desulfurization in the furnace. The CaO powder is injected into the hearth by adopting compressed air, so that the full mixing reaction in the hearth is facilitated. And ammonia water (or urea) is sprayed into the region with the smoke temperature of 850-.

In the convection heating surface 5 and the area with the smoke temperature of 300-. The ammonia water (or urea) adopts a pump conveyer and a compressed air atomization mode, so that the ammonia water (or urea) is quickly gasified and mixed in a hearth for reaction, and the reaction is ensured to be full.

It is noted that CaO powder is hygroscopic, reacts with water to form alkali, is corrosive, and is accompanied by a large amount of heat generation, and the reaction formula is: CaO + H₂O→Ca(OH)₂. Therefore, the CaO powder is sprayed before the ammonia water (or urea) is sprayed, and a certain safety distance is kept between the CaO powder and the ammonia water (or urea) to prevent the spray nozzle from being corroded by alkali.

In the layer-combustion boiler structure and the boiler desulfurization and denitration method provided by the embodiments, calcium oxide powder and ammonia water (or urea) are sprayed into a proper region of a hearth, and a denitration catalyst installation space is reserved in a proper region of a convection heating surface 5, so that desulfurization and denitration in a boiler are realized. Solves the problem of controlling SO in the combustion process of the coal-fired industrial boiler₂、NO_xThe generation problem of the boiler reduces the treatment intensity of pollutants at the tail of the boiler; the structure of the boiler system is simplified. The environment-friendly emission requirement is met, the investment of environment-friendly equipment and the running cost of the environment-friendly equipment are reduced, and a placing space is reserved for other equipment; has better economic benefit and social benefit.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.