阅读说明：本技术 一种超临界co2锅炉的分布式风幕装置 (Supercritical CO2Distributed air curtain device of boiler ) 是由 林郁郁 张丰 顾明言 杨莉 徐中文 黄庠永 陈萍 伍佳佳 袁金燕 朱雨涵 阮晨杰 于 2020-11-18 设计创作，主要内容包括：本发明公开了一种超临界CO_2锅炉的分布式风幕装置,属于锅炉燃烧技术领域。本发明包括：引风机构,其包括至少一台高速引风机,所述高速引风机的进口通过管道连接锅炉炉体；所述高速引风机抽取部分省煤器后的烟气；喷气机构,其包括主进风管、气流扁平狭缝喷嘴和分流管,所述主进风管一端连接高速引风机的出口,另一端连接分流管；所述分流管的端部连接气流扁平狭缝喷嘴,所述气流扁平狭缝喷嘴的出口正对燃烧器上部热负荷集中处垂直分布。本发明的超临界CO_2锅炉的分布式风幕装置,出风均匀,防止风膜长期贴附水冷壁墙体会对墙体产生风蚀导致的水冷壁墙体寿命缩短,可用于超临界CO_2锅炉的多种燃烧器布置条件中。(The invention discloses supercritical CO 2 Distributed air curtain device of boiler belongs to boiler combustion technology field. The invention comprises the following steps: the air inducing mechanism comprises at least one high-speed induced draft fan, and the inlet of the high-speed induced draft fan is connected with the boiler body through a pipeline; the high-speed induced draft fan extracts smoke behind part of the coal economizer; the air injection mechanism comprises a main air inlet pipe, an airflow flat slit nozzle and a flow dividing pipe, wherein one end of the main air inlet pipe is connected with an outlet of the high-speed induced draft fan, and the other end of the main air inlet pipe is connected with the flow dividing pipe; the end part of the flow dividing pipe is connected with an airflow flat slit nozzle, and an outlet of the airflow flat slit nozzle is vertically distributed right opposite to the upper heat load concentrated part of the combustor. Supercritical CO of the invention 2 Distributed air curtain device of boiler, air-out is even, prevents that wind film from long-term attached water-cooling wall body can be to wallThe service life of the water wall body is shortened due to wind erosion generated by the body, and the method can be used for supercritical CO 2 Various burner arrangement conditions of the boiler.)

1. Supercritical CO₂The distributed air curtain device of the boiler is arranged at a gap between a boiler wall and a water wall and used for cooling the water wall, and comprises an air inducing mechanism and an air spraying mechanism, wherein the air inducing mechanism comprises a high-speed draught fan (500), and an inlet of the high-speed draught fan (500) is connected with a boiler body (100) through a pipeline; flue gas behind high-speed draught fan (500) extraction part economizer (400), jet-propelled mechanism (300) are including main air-supply line (310) and shunt tubes (320), the export of high-speed draught fan (500) is connected to main air-supply line (310) one end, shunt tubes (320) are connected to the other end, its characterized in that(ii) a The air injection mechanism (300) further comprises an air flow flat slit nozzle (330), the end part of the shunt pipe (320) is connected with the air flow flat slit nozzle (330), and the outlet of the air flow flat slit nozzle (330) is vertically distributed right opposite to the upper heat load concentrated part of the combustor (200).

2. The supercritical CO of claim 1₂Distributed air curtain device of boiler, its characterized in that, boiler furnace body (100) has four sides brickwork, including two relative broadsides and two relative narrow faces, and the flat slit nozzle of air current (330) is equidistant interval distribution on the broadside, distributes side by side on the narrow face, combustor (200) adopt two four corners tangential circle combustors, distributes in the interval department of the flat slit nozzle of broad face brickwork air current (330), the flat slit nozzle of air current (330) satisfies the following relation with the distance of combustor (200): for the nozzles between the burners (200), the distance W1 between the burner (200) and the gas flow flat slit nozzle (330) satisfies the relation W1 ═ L1-L1/2(K1+ K2), wherein L1 is the distance between adjacent burners (200), Q is the circulating flue gas flow rate, K1 is a dimensionless coefficient related to the circulating flue gas flow rate Q, and K2 is a dimensionless coefficient related to the nozzle penetration depth H1 into the hearth; for the wall surface without distributed burners (200), the width W2 of the airflow flat slit nozzle (330) satisfies the relation W2 ═ L2/(K1+ K2+ K3), wherein L2 is the distance between the furnace walls of the non-distributed burners (200), and K3 is a dimensionless parameter related to the vertical distance H2 from the inner wall of the furnace wall of the non-distributed burners (200) to the adjacent burner (200).

3. The supercritical CO of claim 1₂The distributed air curtain device of the boiler is characterized in that the air flow flat slit nozzle (330) consists of a nozzle and a guide plate (340), and the nozzle is in a Tesla valve shape; the guide plates (340) are uniformly arranged at the front ends of the outlets of the nozzles and are parallel to the flow direction of the airflow.

4. The supercritical CO of claim 3₂Distributed air curtain device of boiler, characterized in that, the baffle (340) uses titanium alloy to resist at the pipeline kinkGrinding steel, using common steel for other straight pipe sections, wherein the shape of the guide plate (340) is rectangular, and the section of the guide plate is wedge-shaped.

5. The supercritical CO of claim 3₂The distributed air curtain device of the boiler is characterized in that grooves (341) are formed in the guide plate (340) along the airflow direction, the depth of each groove (341) is 0.2-0.4mm, and WC wear-resistant layers are formed on the inner sides of the grooves (341).

6. The supercritical CO of claim 1₂The distributed air curtain device of the boiler is characterized in that the pipe diameter d of the shunt pipe (320) satisfies the relation: d ═ 4Q/[ rho ])^1/2And Q is the circulating flue gas volume, rho is the circulating flue gas density, u is the flue gas velocity in the shunt tubes (320), the material is wear-resisting high temperature resistant metal, and the outside is wrapped with a heat insulation material which is rock wool or glass wool.

7. The supercritical CO of claim 6₂The distributed air curtain device of the boiler is characterized in that the pipe diameter D of the main air inlet pipe (310) and the pipe diameter D of the shunt pipe (320) satisfy the relation: d ═ 1.2-1.5D, and the material is wear-resistant and high-temperature-resistant metal.

8. The supercritical CO of claim 1₂The distributed air curtain device of the boiler is characterized in that the high-speed induced draft fan (500) is a centrifugal fan, and the number of the induced draft fans is one or more than one.

Technical Field

The invention belongs to the technical field of boiler combustion, and particularly relates to supercritical CO₂Distributed air curtain device of boiler.

Background

At present, due to the limitation of pressure resistance and temperature resistance of materials, the steam temperature and pressure of the traditional steam boiler cannot be improved to a great extent, and the efficiency of the traditional steam boiler is improved to a very slow stage. Supercritical CO₂The boiler has higher cycle efficiency in a medium temperature region compared with a steam Rankine cycle, and a matched turbine has small volume and compact integral structure and is more and more concerned by researchers at home and abroad. However due to supercritical CO₂The physicochemical property of the working medium in the boiler is changed, the heat transfer performance is lower than that of the conventional steam boiler, the average heat absorption temperature is higher than that of the conventional steam boiler, particularly, the temperature of the working medium is high at the inlet of a water-cooled wall, and the phenomenon of overtemperature of the water-cooled wall is easily caused in a hearth heat load concentrated area, so that the water-cooled wall is cracked and even tubes are exploded, and potential safety hazards and economic loss are caused.

In order to solve the above problems, there have been searched, for example, patent application nos.: 201310375338.0, filing date: 26 months 8 in 2013, the name of the invention is: the utility model provides a device of high temperature corrosion coking is prevented to membrane type water-cooled wall boiler, a plurality of hood formula nozzles are evenly arranged to the device in the region that corresponds with furnace main combustion area on the boiler water-cooled wall side wall, set up to the side wall bellows that all hood formula nozzles provided the wind regime on boiler water-cooled wall side wall outer wall, draw forth partly overgrate air from the boiler main air duct and enter into the side wall bellows, and hug closely boiler water-cooled wall side wall inner wall parallel blowout through a plurality of hood formula nozzle, form adherence wind protection film at boiler water-cooled wall side wall inner wall, thereby avoid boiler high temperature corrosion and coking. The device mainly comprises a hood type nozzle arranged on the side wall of the water wall of the boiler, and a plurality of spray nozzles are uniformly designed at one end of the nozzle extending into the boiler along the circumferential direction. The device has the following defects: the wind cap type nozzles are arranged at gaps among the water cooling walls, the air outlet of the nozzles is not uniform enough, and the wind film is attached to the water cooling walls for a long time to generate wind erosion on the walls, so that the service life of the water cooling walls is shortened.

Again as in patent application No.: 202010238298.5, filing date: 3, 20 days in 2020, the name of the invention is: a high-efficiency wall-attached air system and a method for preventing high-temperature corrosion of a water cooling wall of a front-wall and rear-wall opposed firing boiler comprise a hot secondary air pipeline, a booster fan, a plurality of wall-attached air bellows, a plurality of wall-attached air branch pipes and a plurality of wall-attached air nozzles; one adherence wind bellows corresponds an adherence wind branch pipe and an adherence wind nozzle, and hot overgrate air pipeline is linked together through booster fan and the entry of each adherence wind bellows, and the export of each adherence wind bellows is linked together through the adherence wind branch pipe that corresponds and the adherence wind nozzle that corresponds on the boiler side wall, and all adherence wind nozzles divide into two sets ofly, and one of them group adherence wind nozzle is located the left side wall of boiler, and another group adherence wind nozzle is located the right side wall of boiler, is provided with the governing valve on the adherence wind branch pipe. The disadvantages of the system are: the application range is not wide only for the boiler with the opposed burners; the nozzle arrangement only has a left wall and a right wall, and all water-cooled walls cannot be protected.

In summary, how to address supercritical CO₂The boiler designs a system which has even air outlet and prevents the air film from attaching to the water cooling wall body for a long time to cause the shortening of the service life of the water cooling wall body caused by wind erosion on the wall body, and is a problem to be solved urgently.

Disclosure of Invention

1. Technical problem to be solved by the invention

Aiming at the technical problems of nonuniform air outlet of a nozzle and wind erosion of a wall body caused by parallel air flow and a water wall in a water wall overtemperature system, the invention provides supercritical CO₂The distributed air curtain device of the boiler has uniform air outlet, and prevents the air film from attaching to the water cooling wall body for a long time, so that the service life of the water cooling wall body is shortened due to wind erosion generated on the wall body.

2. Technical scheme

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

the invention relates to supercritical CO₂The distributed air curtain device of the boiler is arranged at a gap between a boiler wall and a water wall and used for cooling the water wall, and comprises an air inducing mechanism and an air spraying mechanism, wherein the air inducing mechanism comprises a high-speed induced draft fan, and the inlet of the high-speed induced draft fan is connected with a boiler body through a pipeline; flue gas behind the high-speed draught fan extraction part economizer, jet-propelled mechanism includes main air-supply line and shunt tubes, the export of high-speed draught fan is connected to main air-supply line one end, and the shunt tubes is connected to the other end, jet-propelled mechanism still includes the flat slit nozzle of air current, the flat slit nozzle of end connection air current of shunt tubes, the export of the flat slit nozzle of air current is just to the perpendicular distribution of the concentrated department of combustor upper portion heat load.

The distributed air curtain device realizes the control of air inlet by utilizing the power supply, the valve switches of the smoke pipeline and the main air inlet pipeline; meanwhile, the high-speed induced draft fan is adjustable, so that the wind speed can be controlled.

Furthermore, the boiler body is provided with four furnace walls which comprise two opposite wide surfaces and two opposite narrow surfaces, the airflow flat slit nozzles are distributed on the wide surfaces at equal intervals and are distributed on the narrow surfaces side by side, the combustor adopts a double-four-corner tangential circle combustor and is distributed at the intervals of the airflow flat slit nozzles on the wide furnace walls, and the distances between the airflow flat slit nozzles and the combustor meet the following relations: for the nozzles between the burners, the distance W1 between the burners and the gas flow flat slit nozzle satisfies the relation W1 ═ L1-L1/2(K1+ K2), wherein L1 is the distance between adjacent burners, Q is the circulating flue gas flow rate, K1 is a dimensionless coefficient related to the circulating flue gas flow rate Q, and K2 is a dimensionless coefficient related to the depth H1 of the nozzle extending into the hearth; for the wall surface without distributed burners, the width W2 of the airflow flat slit nozzle satisfies the relation W2 ═ L2/(K1+ K2+ K3), wherein L2 is the distance between the furnace walls of the non-distributed burners, and K3 is a dimensionless parameter related to the vertical distance H2 between the inner wall of the furnace wall of the non-distributed burners and the adjacent burners.

Furthermore, the airflow flat slit nozzle consists of a nozzle and a guide plate, and the nozzle is in a Tesla valve shape; the guide plate is uniformly arranged at the front end of the outlet of the nozzle and is parallel to the flow direction of the airflow.

Furthermore, the flow guide plate is made of titanium alloy wear-resistant steel at the bent part of the pipeline, the other straight pipe sections are made of common steel, the flow guide plate is rectangular, and the section of the flow guide plate is wedge-shaped.

Furthermore, grooves are formed in the guide plate along the airflow direction, the depth of each groove is 0.2-0.4mm, and WC wear-resistant layers are formed on the inner sides of the grooves.

Further, the pipe diameter d of the shunt pipe satisfies the relation: d ═ 4Q/[ rho ])^1/2And Q is the circulating flue gas volume, rho is the circulating flue gas density, u is the flue gas velocity in the shunt tubes, the material is wear-resisting high temperature resistant metal, and the outside is wrapped with a heat insulation material which is rock wool or glass wool.

Furthermore, the pipe diameter D of the main air inlet pipe and the pipe diameter D of the shunt pipe (320) satisfy the relation: d ═ 1.2-1.5D, and the material is wear-resistant and high-temperature-resistant metal.

Furthermore, the high-speed induced draft fan is a centrifugal fan, and is one or more than one.

3. Advantageous effects

Compared with the prior art, the technical scheme provided by the invention has the following remarkable effects:

(1) supercritical CO of the invention₂The distributed air curtain device of the boiler has a certain distance between the air flow slit nozzle and the water wall, the air outlet is uniform, the air outlet direction is vertical to the water wall, and the air outlet is prevented from being blockedThe long-term adhesion of the wind-stop film to the water-cooled wall body can shorten the service life of the water-cooled wall body caused by wind erosion generated on the wall body, and can be used for supercritical CO₂Various burner arrangement conditions of the boiler;

(2) supercritical CO of the invention₂The distributed air curtain device of the boiler adopts a distributed air curtain and can be flexibly distributed under the condition of not influencing the normal combustion of a combustor according to a specific hearth structure. Under the conditions that the heat load area of the wall surface of the hearth is large and the combustion environment in the furnace is allowed (namely the normal combustion environment is not influenced), the multistage arrangement can be adopted, and the hearth is regulated and controlled together to avoid overtemperature;

(3) supercritical CO of the invention₂The distributed air curtain device of the boiler utilizes a high-speed draught fan to lead out flue gas to be sprayed out from a high-speed airflow flat slit nozzle, an air curtain is formed on a water-cooled wall, and the heat can be effectively blocked or delayed to be transferred to the water-cooled wall by adjusting the air speed of the nozzle, so that the overtemperature of the water-cooled wall is avoided;

(4) supercritical CO of the invention₂The distributed air curtain device of the boiler has a larger heat load concentration area when the boiler with a larger boiler body burns, and a plurality of nozzles can be arranged at different positions in the vertical direction of the boiler body, so that the air flow speed and the blocking effect of the heat load concentration area are ensured;

(5) supercritical CO of the invention₂In the distributed air curtain device of the boiler, when high-speed airflow flows at a position with higher heat load, partial surrounding airflow can be driven, so that the retention time of partial fuel in a high-temperature area is reduced, and the generation of thermal NOx is favorably reduced; at the position where the flow velocity of the air flow is small, the flowing air flow can disturb the surrounding thermal force field, so that the heat transfer is enhanced;

(6) supercritical CO of the invention₂The distributed air curtain device of the boiler can roll and carry heat at the part of the heat load concentration position of the hearth around the sprayed air flow, and the heat load of the hearth can be uniform.

Drawings

FIG. 1 shows supercritical CO of the present invention₂The structure of the distributed air curtain device of the boiler is schematic;

FIG. 2 is a top view of the overall structure of the high velocity gas flow flat slit nozzle of the present invention;

FIG. 3 is a cross-sectional view of the furnace inner portion of the present invention taken along section A-A;

fig. 4 is a schematic view of the structure of the baffle of the present invention.

The notation in the figure is:

100. a boiler body;

200. a burner;

300. an air injection mechanism; 310. a main air inlet pipe; 320. a shunt tube; 330. an air flow flat slit nozzle; 340. a baffle; 341. A groove;

400. a coal economizer;

500. a high-speed induced draft fan;

600. an air intake control valve.

Detailed Description

For a further understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings and examples.

Example 1

As shown in fig. 1 to 4, the arrows in the drawings indicate the traveling direction of the flue gas, and the supercritical CO of the embodiment₂The distributed air curtain device of the boiler, set up in the interval department between furnace wall and water wall and be used for cooling the water wall, include: the induced draft mechanism comprises at least one high-speed induced draft fan 500, the inlet of the high-speed induced draft fan 500 is connected with the boiler body 100 through a pipeline, and an air inlet control valve 600 is arranged on the pipeline; the high-speed induced draft fan 500 extracts part of the flue gas after the economizer 400; the air injection mechanism 300 comprises a main air inlet pipe 310, an airflow flat slit nozzle 330 and a flow dividing pipe 320, wherein one end of the main air inlet pipe 310 is connected with the outlet of the high-speed induced draft fan 500, and the other end of the main air inlet pipe is connected with the flow dividing pipe 320; the end of the shunt tube 320 is connected to the flat slot nozzle 330, and the outlet of the flat slot nozzle 330 is vertically distributed to the upper part of the burner 200 where the heat load is concentrated. The flue gas pipeline behind the economizer 400 is used for inducing air, the flue gas has a certain temperature, the heat loss of the hearth can be reduced after the flue gas is introduced into the hearth, and the flue gas required by partial flue gas circulation can be provided.

As shown in FIG. 2, the arrows in the figure indicate the traveling direction of the flue gas, and the supercritical CO of the embodiment₂Distributed air curtain device for boiler, basic structure thereofThe structure lies in, the combustor 200 adopts two four corners tangential circle combustors, main air inlet pipe 310 is connected to shunt tubes 320 one end, and the flat slit nozzle 330 of air current is connected to the other end, boiler body 100 has four sides brickwork, including two relative broad face and two relative narrow face, and the difference with prior art lies in, the flat slit nozzle 330 of air current is at equidistance interval distribution on the broad face, distributes side by side on the narrow face. The burners 200 are distributed at intervals of the gas flow flat slit nozzle 330 on the wide surface of the furnace wall, and the distance between the gas flow flat slit nozzle 330 and the burners 200 satisfies the following relation: for the flat slit nozzle 330 between the burners 200, the distance W1 between the burners 200 and the flat slit nozzle 330 satisfies the relation W1 ═ L1-L1/2(K1+ K2), wherein L1 is the distance between adjacent burners 200, Q is the recycled flue gas flow rate, K1 is a dimensionless coefficient related to the recycled flue gas flow rate Q, and K2 is a dimensionless coefficient related to the port penetration depth H1; for the wall surface of the non-distributed burner 200, the width W2 of the flat air slit nozzle 330 satisfies the relation W2 ═ L2/(K1+ K2+ K3), where L2 is the distance between the furnace walls of the non-distributed burner 200, and K3 is a dimensionless parameter related to the vertical distance H2 from the inner wall of the furnace wall of the non-distributed burner 200 to the adjacent burner 200. The air curtain airflow flat slit nozzle 330 keeps a certain distance from the combustor 200, so that the phenomena of great influence on the normal combustion of the combustor 200 and the harmful phenomena of slag bonding or flameout and the like of the combustor caused by low-temperature smoke of the air curtain are avoided, and the distributed air curtain can be flexibly distributed according to a specific hearth structure under the condition of not influencing the normal combustion of the combustor 200. Under the condition that the heat load area of the wall surface of the hearth is large and the combustion environment in the furnace is allowed (namely the normal combustion environment is not influenced), the multistage arrangement can be adopted, and the hearth can be regulated and controlled together to avoid overtemperature.

Further, the flat slit nozzle 330 for airflow is composed of a nozzle and a guide plate 340, the nozzle is in a tesla valve shape, and the airflow can further increase the flow speed at the nozzle; the guide plate 340 is uniformly arranged at the front end of the outlet of the nozzle and is parallel to the flow direction of the airflow.

In this embodiment, the flow guide plate 340 is made of titanium alloy wear-resistant steel at the bent portion of the pipeline, the remaining straight pipe sections are made of common steel, the flow guide plate is rectangular, and the cross section of the flow guide plate is wedge-shaped.

In addition, the high-speed induced draft fan 500 is a centrifugal fan, and the whole airflow speed is increased.

In the present invention, the pipe diameter of the shunt pipe 320 is important, and directly affects the cooling of the boiler, and the pipe diameter d of the shunt pipe satisfies the relation: d ═ 4Q/[ rho ])^1/2And Q is the circulating flue gas volume, rho is the circulating flue gas density, u is the flue gas velocity in the shunt tubes 320, and the material is wear-resisting high temperature resistant metal, and the outside is wrapped with a heat insulation material which is rock wool or glass wool.

In this embodiment, the pipe diameter D of the main air inlet pipe 310 and the pipe diameter D of the shunt pipe 320 satisfy the following relation: d ═ 1.2-1.5D, and the material is wear-resistant and high-temperature-resistant metal. For example, in the present embodiment, it is preferable that the diameter D of the main air inlet duct 310 be 1.2D.

During normal use, the inventor finds that the surface of the deflector 340 is worn seriously, and a small amount of smoke contained in the smoke flushes the outer surface of the wedge-shaped head of the deflector 340, so as to accelerate the wear of the deflector 340, so the inventor tries several ways, such as directly spraying a WC wear-resistant layer on the surface of the deflector 340, but the effect is not as good as possible. Through a large number of tests and analyses, the inventor combines the content of fluid mechanics, the guide plate 340 is provided with the grooves 341 along the airflow direction, the depth of the grooves 341 is 0.2-0.4mm, the WC wear-resistant layer is formed on the inner side of the grooves 341, the thickness of the WC wear-resistant layer is 0.1mm, and electrostatic spraying is adopted, so that after a period of use, the effect of abrasion of the guide plate 340 is better than that of direct spraying of the wear-resistant layer in the same time. The inventor analyzes that the possible reason is that under the action of the nozzle in the shape of a Tesla valve and the guide plate 340 designs the groove 341, smoke can form local vortex, the smoke vortex meets the groove 341 in the process of traveling, the groove 341 is arranged to enable most of moving smoke particles to be accumulated inside the groove 341 and move along the inside of the groove 341, and because a WC wear-resistant layer is formed inside the groove 341, the wear is relatively small, and the head of the guide plate 340 at the part other than the groove 341 only passes through the smoke and is also small, so that the wear of the guide plate 340 can be effectively reduced.

It should be noted that the baffle 340 and the shunt 320 are used to make the air from the nozzle uniform, and the slit nozzle is used to eject high-speed air. The high-speed induced draft fan 500 extracts 5% -10% of the main air inlet pipe 310 and fixes on the furnace wall, when the main air inlet pipe 310 divides into a plurality of shunt pipes 320 to the nozzle after the furnace wall inner wall, the flue gas enters the furnace wall through the main air inlet pipe 310, because the water-cooling wall has different heat loads at different positions of the horizontal section, firstly the flue gas is distributed once through the shunt pipes 320, when the air current reaches the nozzle, the air outlet of the nozzle is uniform through the guide plate 340. The high-speed air flow flat slit nozzle 330 is arranged at the upper part of the combustor 200 where the heat load is concentrated, the high-speed draught fan 500 forms an air curtain from the high-speed air flow flat slit nozzle 330 after extracting part of the flue gas of the economizer 400, the heat of the heat load concentrated area is blocked or delayed to be transferred to the water-cooled wall, the overtemperature of the water-cooled wall is avoided, and after the air flow flows through the position with higher heat load of the hearth, the speed is reduced, so that the heat of the hearth is not blocked to be transferred to the.

The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.