Circulating fluidized bed boiler and boiler system

Abstract

The invention relates to the technical field of flue gas denitration, in particular to a circulating fluidized bed boiler and a boiler system. The circulating fluidized bed boiler comprises a boiler body, a combustion chamber is arranged in the boiler body, a primary air inlet is formed in the bottom of the boiler body, and the combustion chamber comprises a dense-phase area; the air distribution plate is installed in the boiler body, the air distribution plate is located between the primary air inlet and the dense-phase area, and a plurality of air caps allowing airflow to flow into the combustion chamber from the primary air inlet are arranged on the air distribution plate at intervals; the urea spraying mechanism is mounted on the air distribution plate and vertically faces the central area of the dense-phase area; a spraying hole of the urea spraying mechanism is positioned above the air cap, so that a urea solution can be sprayed to the central area of the dense-phase area; the urea spraying mechanism is further arranged to allow airflow to flow into the combustion chamber from the primary air inlet. The circulating fluidized bed boiler can prevent the nitrogen oxide content of the generated flue gas from increasing when the circulating fluidized bed boiler is in a low-load state.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas denitration, and in particular to a circulating fluidized bed boiler and a boiler system. Background Art

[0002] The flue gas discharged from the circulating fluidized bed boiler contains a large amount of nitrogen oxides. In order to avoid the generated nitrogen oxides from polluting the environment, the flue gas must be denitrated. At present, a nozzle is usually installed at the flue gas inlet of the cyclone separator, and the nozzle sprays urea solution into the smoke inlet channel of the cyclone separator. The urea solution and the nitrogen oxides in the flue gas react rapidly under high temperature conditions to form nitrogen and water, thereby achieving flue gas denitration.

[0003] However, when the operating load of the circulating fluidized bed boiler is reduced, the temperature of the flue gas in the cyclone separator will be lower than the optimal temperature range required for the above-mentioned denitrification reaction, resulting in a decrease in the reaction rate between the urea solution and nitrogen oxides, thereby causing an increase in the content of nitrogen oxides in the flue gas. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem in the prior art that the nitrogen oxide content of the flue gas generated by the circulating fluidized bed boiler increases when the boiler is in a low load state.

[0005] In order to achieve the above-mentioned objectives, the present invention provides a circulating fluidized bed boiler on one hand, which comprises: a boiler body, a combustion chamber is provided inside the boiler body, a smoke outlet connected to the combustion chamber is provided on the top of the boiler body, a primary air inlet is provided on the bottom of the boiler body, the combustion chamber is located between the smoke outlet and the primary air inlet, and the combustion chamber includes a dense phase area; an air distribution plate, the air distribution plate is installed in the boiler body, the air distribution plate is located between the primary air inlet and the dense phase area, and a plurality of wind hoods are arranged on the air distribution plate at intervals to allow airflow to flow from the primary air inlet into the combustion chamber; and a urea spraying mechanism, the urea spraying mechanism is installed on the air distribution plate and vertically faces the central area of ​​the dense phase area; the urea spraying mechanism is used to be connected to a urea solution providing device, and the spray hole of the urea spraying mechanism is located above the wind hood so as to be able to spray urea solution into the central area of ​​the dense phase area; and the urea spraying mechanism is also configured to allow airflow to flow from the primary air inlet into the combustion chamber.

[0006] In some embodiments, the urea spraying mechanism includes a plurality of urea sprayers distributed at intervals, and the urea sprayers can be communicated with the urea solution supply device.

[0007] In some embodiments, the urea sprayer includes an air duct, an air duct cover and a liquid delivery pipe; the air duct seals and passes through an air distribution plate, the top end of the air duct is higher than the top surface of the air distribution plate, the bottom end of the air duct is flush with the bottom surface of the air distribution plate, and the air duct has an air guide channel extending along its axial direction; the air duct cover includes an air duct peripheral plate and an air duct top plate; the air duct peripheral plate is coaxially sleeved on the outside of the air duct, and the inner side surface of the air duct peripheral plate is radially spaced apart from the outer side surface of the air duct; the bottom end of the air duct peripheral plate is sealed and connected to the top surface of the air distribution plate; a plurality of circumferentially spaced first ventilation holes are provided on the air duct peripheral plate, and the first ventilation holes extend obliquely from top to bottom from the air inlet end to the air outlet end; the air hood top plate is sealed and connected to the top end of the air hood peripheral plate, and the air hood top plate is sealed and connected to the air duct The top of the air duct is vertically spaced apart; the liquid delivery pipe passes through the air guide channel of the air guide pipe and the top plate of the wind hood, the axis of the liquid delivery pipe coincides with the axis of the air guide pipe, and the outside of the liquid delivery pipe is sealed and connected to the top plate of the wind hood; the liquid delivery pipe has a liquid channel extending along its axial direction; the top of the liquid delivery pipe is located above the top plate of the wind hood, and the top of the liquid channel is sealed by a sealing member; the liquid delivery pipe is provided with a plurality of spray holes distributed at intervals in the circumference and connected to the liquid channel, the spray holes extend obliquely from the bottom to the top of the liquid inlet end to the liquid outlet end, and the spray holes are located between the top of the liquid delivery pipe and the top plate of the wind hood; the bottom end of the liquid delivery pipe is located below the bottom surface of the air distribution plate, and the bottom end of the liquid delivery pipe can be connected to the urea solution providing device.

[0008] In some embodiments, the multiple spray holes include multiple first spray holes, multiple second spray holes and multiple third spray holes, the multiple first spray holes are circumferentially spaced at the same height, the multiple second spray holes are circumferentially spaced at the same height, the multiple third spray holes are circumferentially spaced at the same height, the distribution position of the first spray holes is higher than the distribution position of the second spray holes, and the distribution position of the second spray holes is higher than the distribution position of the third spray holes.

[0009] In some embodiments, the distance between the liquid inlet end of the third spray hole and the top surface of the air hood top plate is in the range of 700 mm to 900 mm.

[0010] In some embodiments, the sealing member includes a counterweight block, a connecting rod and a blocking block; the counterweight block is provided with a slot, the slot is recessed from the bottom surface of the counterweight block to the top surface of the counterweight block; the top end of the liquid delivery tube is movably inserted into the slot; the connecting rod is located in the slot, the top end of the connecting rod is fixedly connected to the slot top surface, the bottom end of the connecting rod is movably inserted into the top end of the liquid channel, and the axis of the connecting rod coincides with the axis of the liquid channel; the blocking block is fixedly connected to the bottom end of the connecting rod, the blocking block is located in the top end of the liquid channel and the top end of the liquid channel is Sealing; a first limit block and a second limit block fixedly connected to the liquid delivery pipe are provided in the liquid channel, the first limit block is located above the blocking block, and the second limit block is located between the spray hole and the wind hood top plate; the blocking block can move vertically between the first limit block and the second limit block along the liquid channel; when the blocking block contacts the first limit block, the first spray hole, the second spray hole and the third spray hole are connected to the liquid channel; when the blocking block contacts the second limit block, the first spray hole, the second spray hole and the third spray hole are blocked by the blocking block.

[0011] In some embodiments, the first limit block and the second limit block are arranged in a ring shape, the inner diameter of the first limit block is smaller than the diameter of the blocking block and larger than the diameter of the connecting rod, and the inner diameter of the second limit block is smaller than the diameter of the blocking block.

[0012] In some embodiments, the hood includes an air pipe and an air guide cover, the air pipe is sealed and passes through an air distribution plate, the top end of the air pipe is higher than the top surface of the air distribution plate, the bottom end of the air pipe is flush with the bottom surface of the air distribution plate, and the air pipe has an air delivery channel extending along its axial direction; the air guide cover includes a cover body peripheral plate and a cover body top plate; the cover body peripheral plate is coaxially sleeved on the outside of the air pipe, and the inner side surface of the cover body peripheral plate is spaced apart from the outer side surface of the air pipe; the bottom end of the cover body peripheral plate is sealed and connected to the top surface of the air distribution plate; a plurality of circumferentially spaced second ventilation holes are provided on the cover body peripheral plate, and the second ventilation holes extend obliquely from top to bottom from the air inlet end to the air outlet end; the cover body top plate is sealed and connected to the top end of the cover body peripheral plate, and the cover body top plate is spaced apart from the top end of the air pipe.

[0013] In some embodiments, the ratio of the inner diameter of the wind shield peripheral plate to the inner diameter of the shield body peripheral plate is equal to the ratio of the diameter of the air guide channel to the diameter of the air delivery channel.

[0014] The present invention also provides a boiler system, which includes a urea solution providing device and the circulating fluidized bed boiler of the above embodiment, wherein the urea solution providing device is located outside the boiler body and is connected to the urea spraying mechanism.

[0015] The technical solution of the present invention has the following beneficial effects:

[0016] The airflow can enter the combustion chamber through the primary air inlet and the wind cap on the air distribution plate in turn, and the airflow can also enter the combustion chamber through the primary air inlet and the urea spray mechanism in turn, thereby providing oxygen for the combustion of the coal particles in the combustion chamber. The urea spray mechanism is installed on the air distribution plate and vertically faces the central area of ​​the dense phase zone, and the spray hole of the urea spray mechanism is located above the wind cap, so the distance between the spray hole of the urea spray mechanism and the central area of ​​the dense phase zone is relatively close, and the urea spray mechanism can directly spray urea solution to the central area of ​​the dense phase zone. The central area of ​​the dense phase zone is a high-temperature and low-oxygen environment. Even if the circulating fluidized bed boiler is operated under a low-load state, the temperature of the central area of ​​the dense phase zone can reach more than 800°C. The urea solution sprayed to the central area of ​​the dense phase zone can fully react with the nitrogen oxides generated by the combustion of the coal particles in the combustion chamber under a high-temperature and low-oxygen environment, and fully remove the nitrogen oxides in the flue gas, thereby preventing the nitrogen oxide content in the flue gas from increasing when the circulating fluidized bed boiler is in a low-load state. Therefore, the circulating fluidized bed boiler of the present invention can avoid an increase in the nitrogen oxide content of the flue gas generated when the circulating fluidized bed boiler is in a low-load state. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a circulating fluidized bed boiler in one embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of the installation of a urea sprayer in one embodiment of the present invention;

[0019] Figure 3 yes Figure 2 A partial enlarged schematic diagram of part A;

[0020] Figure 4 This is a schematic diagram of the installation of the hood.

[0021] Description of Reference Numerals

[0022] 1. Boiler body; 11. Combustion chamber; 111. Dense phase area; 12. Smoke outlet; 13. Primary air inlet;

[0023] 2. air distribution plate; 21. wind cap; 211. air delivery pipe; 2111. air delivery channel; 212. air guide cover; 2121. cover body peripheral plate; 2122. cover body top plate; 213. second ventilation hole;

[0024] 3. Urea spraying mechanism; 31. Urea sprayer; 311. Air guide pipe; 3111. Air guide channel; 312. Air guide cover; 3121. Wind cover peripheral plate; 3122. Wind cover top plate; 3123. First ventilation hole; 313. Liquid delivery pipe; 3131. Liquid channel; 3132. Spray hole; 3133. First spray hole; 3134. Second spray hole; 3135. Third spray hole; 3136. First limit block; 3137. Second limit block; 314. Sealing element; 3141. Counterweight block; 3142. Connecting rod; 3143. Blocking block; 3144. Slot; 32. Electric regulating valve; 33. Flow meter;

[0025] 4. Cyclone separator. DETAILED DESCRIPTION

[0026] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention, rather than to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0027] The temperature required for rapid pyrolysis of urea solution is about 800℃ or above, and the temperature of the dense phase zone of the combustion chamber of the circulating fluidized bed boiler is about 850℃-950℃ under normal circumstances. However, when the circulating fluidized bed boiler is running at low load, the temperature at the flue gas inlet of the cyclone separator is lower than 800℃, but the temperature of the dense phase zone can also reach 800℃-900℃. Moreover, in the entire dense phase zone, the temperature of the central area of ​​the dense phase zone is the highest, and the central area of ​​the dense phase zone is a high-temperature and low-oxygen environment. Ammonia will preferentially react with nitrogen oxides in the flue gas to denitrify in a low-oxygen state to generate non-toxic and harmless nitrogen and water. Therefore, it is feasible to use the high-temperature and low-oxygen environment in the central area of ​​the dense phase zone to achieve rapid pyrolysis of urea solution when the circulating fluidized bed boiler is running at low load, thereby creating a favorable denitrification environment.

[0028] like Figure 1 to Figure 2As shown, based on the above technical ideas, the present invention provides a circulating fluidized bed boiler. The circulating fluidized bed boiler includes a boiler body 1, an air distribution plate 2 and a urea spraying mechanism 3. The boiler body 1 has a combustion chamber 11 inside, a smoke outlet 12 connected to the combustion chamber 11 is provided at the top of the boiler body 1, a primary air inlet 13 is provided at the bottom of the boiler body 1, the combustion chamber 11 is located between the smoke outlet 12 and the primary air inlet 13, and the combustion chamber 11 includes a dense phase area 111. The air distribution plate 2 is installed in the boiler body 1, the air distribution plate 2 is located between the primary air inlet 13 and the dense phase area 111, and a plurality of air hoods 21 are provided on the air distribution plate 2 to allow airflow to flow from the primary air inlet 13 into the combustion chamber 11. The urea spray mechanism 3 is installed on the air distribution plate 2 and vertically faces the central area of ​​the dense phase area 111; the urea spray mechanism 3 is used to communicate with the urea solution providing device, and the spray hole 3132 of the urea spray mechanism 3 is located above the wind cap 21, so as to be able to spray the urea solution to the central area of ​​the dense phase area 111. And the urea spray mechanism 3 is also configured to allow airflow to flow from the primary air inlet 13 into the combustion chamber 11. Of course, the combustion chamber 11 and the dense phase area 111 are located between the air distribution plate 2 and the smoke outlet 12.

[0029] Specifically, the airflow can enter the combustion chamber 11 through the primary air inlet 13 and the wind cap 21 on the air distribution plate 2 in sequence, and the airflow can also enter the combustion chamber 11 through the primary air inlet 13 and the urea spraying mechanism 3 in sequence, thereby providing oxygen for the combustion of coal particles in the combustion chamber 11. The urea spraying mechanism 3 is installed on the air distribution plate 2 and vertically faces the central area of ​​the dense phase area 111, and the spray hole 3132 of the urea spraying mechanism 3 is located above the wind cap 21, so the spray hole 3132 of the urea spraying mechanism 3 is close to the central area of ​​the dense phase area 111, and the urea spraying mechanism 3 can directly spray urea solution to the central area of ​​the dense phase area 111. The central area of ​​the dense phase area 111 is a high-temperature, low-oxygen environment. Even if the circulating fluidized bed boiler is running at a low load, the temperature of the central area of ​​the dense phase area 111 can reach above 800°C. The urea solution sprayed into the central area of ​​the dense phase area 111 can fully react with the nitrogen oxides generated by the combustion of coal particles in the combustion chamber 11 under a high-temperature, low-oxygen environment, and fully remove the nitrogen oxides in the flue gas, thereby preventing the nitrogen oxide content in the flue gas from increasing when the circulating fluidized bed boiler is at a low load. Therefore, the circulating fluidized bed boiler of the present invention can avoid the increase of the nitrogen oxide content in the flue gas generated when it is at a low load.

[0030] In addition, the coal particles burn in the combustion chamber 11 and generate flue gas, and the urea spraying mechanism 3 delivers the urea solution into the central area of ​​the dense phase zone 111, so the ammonia generated by the pyrolysis of the urea solution and the flue gas begin to fully mix and undergo a denitration reaction in the lower part of the combustion chamber 11, so the entire combustion chamber 11 can be used for the denitration reaction, providing a huge reaction space and sufficient reaction time for the reduction reaction between ammonia and nitrogen oxides. Therefore, compared with applying the urea solution at the flue gas inlet of the cyclone separator 4, the present invention fully utilizes the high temperature environment of the combustion chamber 11 for the denitration reaction, which can greatly increase the time and space required for the reaction, thereby greatly improving the reaction efficiency.

[0031] In addition, those skilled in the art can understand that when using urea solution for denitration, it is usually necessary to first pyrolyze the urea solution to generate ammonia, and the methods usually used in this pyrolysis process are auxiliary steam heating, electric heating, diesel heating and flue gas heating. These pyrolysis methods not only lead to energy loss, but also require the addition of corresponding heating equipment, which ultimately leads to high pyrolysis costs. The circulating fluidized bed boiler of the present invention does not need to add any additional equipment, does not need to consume other forms of energy, and can achieve zero-cost pyrolysis of urea solution by only using the high temperature environment of the dense phase zone 111 of the combustion chamber 11, so it has great advantages in economy.

[0032] like Figure 1 As shown, in some embodiments of the present invention, the urea spraying mechanism 3 includes a plurality of urea sprayers 31 distributed at intervals, and the urea sprayers 31 can be connected to a urea solution providing device.

[0033] Specifically, each urea sprayer 31 is located directly below the central area of ​​the dense phase zone 111, so these urea sprayers 31 can spray urea solution to the central area of ​​the dense phase zone 111, so that a sufficient amount of urea solution can be used for denitration reaction in the central area of ​​the dense phase zone 111. In the denitration method of the present invention, the low oxygen environment in the central area of ​​the dense phase zone 111 is fully utilized, and the advantage that the temperature of the dense phase zone 111 is still relatively high when the circulating fluidized bed boiler is in low-load operation is utilized, so that nitrogen oxides in the flue gas can be removed efficiently, so that the circulating fluidized bed boiler can still meet the emission requirements when it is in low-load operation.

[0034] In some embodiments, the number of urea sprayers 31 is 3-5. On the one hand, it can ensure that the amount of urea solution applied is sufficient; on the other hand, it can reduce the difficulty of modifying the air distribution plate 2.

[0035] like Figure 2 and Figure 3As shown, in some embodiments of the present invention, the urea sprayer 31 includes an air guide pipe 311, an air guide cover 312 and a liquid delivery pipe 313. The air guide pipe 311 passes through the air distribution plate 2 in a sealed manner, the top end of the air guide pipe 311 is higher than the top surface of the air distribution plate 2, the bottom end of the air guide pipe 311 is flush with the bottom surface of the air distribution plate 2, and the air guide pipe 311 has an air guide channel 3111 extending along its axial direction. The wind guide hood 312 includes a wind guide hood peripheral plate 3121 and a wind guide top plate 3122; the wind guide hood peripheral plate 3121 is coaxially sleeved on the outside of the air guide duct 311, and the inner side surface of the wind guide hood peripheral plate 3121 is radially spaced apart from the outer side surface of the air guide duct 311; the bottom end of the wind guide hood peripheral plate 3121 is sealedly connected to the top surface of the air distribution plate 2; the wind guide hood peripheral plate 3121 is provided with a plurality of circumferentially spaced first ventilation holes 3123, and the first ventilation holes 3123 extend obliquely from the air inlet end to the air outlet end thereof from top to bottom; the wind guide top plate 3122 is sealedly connected to the top end of the wind guide hood peripheral plate 3121, and the wind guide top plate 3122 is vertically spaced apart from the top end of the air guide duct 311. The liquid delivery pipe 313 passes through the air guide channel 3111 of the air guide pipe 311 and the wind shield top plate 3122. The axis of the liquid delivery pipe 313 coincides with the axis of the air guide pipe 311. The outside of the liquid delivery pipe 313 is sealed to the wind shield top plate 3122. The liquid delivery pipe 313 has a liquid channel 3131 extending along its axial direction. The top end of the liquid delivery pipe 313 is located above the wind shield top plate 3122. The top end of the liquid channel 3131 is sealed by a sealing member. 314 seal; the liquid delivery pipe 313 is provided with a plurality of spray holes 3132 which are circumferentially spaced and connected to the liquid channel 3131, the spray holes 3132 extend obliquely from the liquid inlet end to the liquid outlet end from the bottom to the top, and the spray holes 3132 are located between the top end of the liquid delivery pipe 313 and the wind hood top plate 3122; the bottom end of the liquid delivery pipe 313 is located below the bottom surface of the air distribution plate 2, and the bottom end of the liquid delivery pipe 313 can be connected to the urea solution providing device.

[0036] Specifically, the air duct 311 passes through the air distribution plate 2 and is sealed therebetween, so that the airflow can flow in the air duct channel 3111 of the air duct 311. The wind shield peripheral plate 3121 circumferentially surrounds the outside of the air duct 311, and the inner side surface of the wind shield peripheral plate 3121 is radially spaced from the outer side surface of the air duct 311, so that the airflow can flow between the air duct 311 and the wind shield peripheral plate 3121.

[0037] In this embodiment, the urea solution providing device can be connected to the bottom end of the liquid delivery pipe 313, so the urea solution providing device can deliver urea solution to the liquid channel 3131, and the urea solution flows from the bottom end of the liquid channel 3131 to the top end of the liquid channel 3131. When the urea solution flows to the spray hole 3132, since the spray hole 3132 extends obliquely upward, the urea solution can be sprayed from the spray hole 3132 to the central area of ​​the dense phase zone 111. Moreover, the airflow entering from the primary air inlet 13 can enter the air guide cover 312 along the air guide channel 3111 of the air guide pipe 311, and then flow to the first ventilation hole 3123 along the channel between the wind cover peripheral plate 3121 and the air guide pipe 311. Since the first ventilation hole 3123 extends obliquely downward, the airflow can flow obliquely downward along the first ventilation hole 3123, so that the coal particles in the combustion chamber 11 are fluidized evenly. In addition, when the airflow flows along the air guide channel 3111 , the liquid delivery pipe 313 can be cooled, which helps prevent the heat of the combustion chamber 11 from being transferred to the urea solution providing device, thereby preventing the urea solution from being decomposed by heat before entering the liquid delivery pipe 313 .

[0038] like Figure 2 and Figure 3 As shown, in some embodiments of the present invention, the plurality of spray holes 3132 include a plurality of first spray holes 3133, a plurality of second spray holes 3134 and a plurality of third spray holes 3135, the plurality of first spray holes 3133 are circumferentially spaced at the same height, the plurality of second spray holes 3134 are circumferentially spaced at the same height, the plurality of third spray holes 3135 are circumferentially spaced at the same height, the distribution position of the first spray holes 3133 is higher than the distribution position of the second spray holes 3134, and the distribution position of the second spray holes 3134 is higher than the distribution position of the third spray holes 3135.

[0039] Specifically, the first spray hole 3133, the second spray hole 3134 and the third spray hole 3135 can spray urea solution to the central area of ​​the dense phase zone 111 at different heights, thereby helping to increase the spray range and enable the flue gas to fully undergo a denitration reaction.

[0040] In some embodiments of the present invention, the distance between the liquid inlet end of the third spray hole 3135 and the top surface of the wind hood top plate 3122 is in the range of 700 mm to 900 mm.

[0041] Specifically, the height of the third spray hole 3135 is relatively high, so the distance between the third spray hole 3135 and the central area of ​​the dense phase area 111 is relatively small, which facilitates the third spray hole 3135 to spray the urea solution to the central area of ​​the dense phase area 111. Of course, the distance between the first spray hole 3133 and the second spray hole 3134 and the distance between the third spray hole 3135 and the central area of ​​the dense phase area 111 is smaller, which also facilitates the spraying of the urea solution to the central area of ​​the dense phase area 111.

[0042] like Figure 2 As shown, in some embodiments of the present invention, the sealing member 314 includes a counterweight block 3141, a connecting rod 3142 and a blocking block 3143; the counterweight block 3141 is provided with a slot 3144, and the slot 3144 is recessed from the bottom surface of the counterweight block 3141 to the top surface of the counterweight block 3141; the top end of the liquid delivery pipe 313 is movably inserted into the slot 3144; the connecting rod 3142 is located in the slot 3144, the top end of the connecting rod 3142 is fixedly connected to the top surface of the slot 3144, the bottom end of the connecting rod 3142 is movably inserted into the top end of the liquid channel 3131, and the axis of the connecting rod 3142 is aligned with the axis of the liquid channel 3131 The axes coincide; the blocking block 3143 is fixedly connected to the bottom end of the connecting rod 3142, the blocking block 3143 is located in the top end of the liquid channel 3131 and seals the top end of the liquid channel 3131; the liquid channel 3131 is provided with a first limit block 3136 and a second limit block 3137 fixedly connected to the liquid delivery pipe 313, the first limit block 3136 is located above the blocking block 3143, and the second limit block 3137 is located between the spray hole 3132 and the wind hood top plate 3122; the blocking block 3143 can move vertically between the first limit block 3136 and the second limit block 3137 along the liquid channel 3131. When the blocking block 3143 contacts the first limiting block 3136, the first spray hole 3133, the second spray hole 3134 and the third spray hole 3135 are connected to the liquid channel 3131; when the blocking block 3143 contacts the second limiting block 3137, the first spray hole 3133, the second spray hole 3134 and the third spray hole 3135 are blocked by the blocking block 3143.

[0043] Specifically, when the demand for urea solution is small, the urea solution supply device will reduce the supply of urea solution, and the pressure of the urea solution in the liquid channel 3131 will decrease. Based on the gravity of the counterweight 3141 itself, the position of the counterweight 3141 drops, and at this time, the counterweight 3141 and the blocking block 3143 can block the first spray hole 3133, so that the urea solution can only be sprayed from the second spray hole 3134 and the third spray hole 3135, and the spray range of the second spray hole 3134 and the third spray hole 3135 remains basically unchanged; or, the counterweight 3141 and the blocking block 3143 can block the first spray hole 3133 and the second spray hole 3134, so that the urea solution can only be sprayed from the third spray hole 3135, and the spray range of the third spray hole 3135 remains basically unchanged. Of course, when the blocking block 3143 contacts the second limiting block 3137, the first spray hole 3133, the second spray hole 3134 and the third spray hole 3135 are blocked by the blocking block 3143. In addition, when the demand for urea solution is large, the urea solution supply device will increase the supply of urea solution, the pressure of the urea solution in the liquid channel 3131 will increase, the position of the counterweight block 3141 will increase, and the first spray hole 3133, the second spray hole 3134 and the third spray hole 3135 can all be put into use. Therefore, the seal 314 can flexibly adjust the number of spray holes 3132 without affecting the spray range, so as to meet the denitration requirements of different working conditions.

[0044] like Figure 2 As shown, in some embodiments of the present invention, the first limit block 3136 and the second limit block 3137 are arranged in a ring shape, the inner diameter of the first limit block 3136 is smaller than the diameter of the blocking block 3143 and larger than the diameter of the connecting rod 3142, and the inner diameter of the second limit block 3137 is smaller than the diameter of the blocking block 3143.

[0045] Specifically, the first limiting block 3136 and the second limiting block 3137 are set to be ring-shaped, which can fully limit the blocking block 3143 and prevent the blocking block 3143 from being blocked by the first limiting block 3136 or the second limiting block 3137.

[0046] like Figure 4As shown, in some embodiments of the present invention, the hood 21 includes an air supply pipe 211 and a guide cover 212. The air supply pipe 211 passes through the air distribution plate 2 in a sealed manner, the top end of the air supply pipe 211 is higher than the top surface of the air distribution plate 2, the bottom end of the air supply pipe 211 is flush with the bottom surface of the air distribution plate 2, and the air supply pipe 211 has an air supply channel 2111 extending along its axial direction. The air deflector 212 includes a hood peripheral plate 2121 and a hood top plate 2122; the hood peripheral plate 2121 is coaxially sleeved on the outside of the air pipe 211, and the inner side surface of the hood peripheral plate 2121 is spaced apart from the outer side surface of the air pipe 211; the bottom end of the hood peripheral plate 2121 is sealedly connected to the top surface of the air distribution plate 2; a plurality of circumferentially spaced second ventilation holes 213 are provided on the hood peripheral plate 2121, and the second ventilation holes 213 extend obliquely from top to bottom from the air inlet end to the air outlet end thereof; the hood top plate 2122 is sealedly connected to the top end of the hood peripheral plate 2121, and the hood top plate 2122 is spaced apart from the top end of the air pipe 211.

[0047] Specifically, the airflow entering from the primary air inlet 13 can enter the guide cover 212 along the air delivery channel 2111 of the air delivery pipe 211, and then flow to the second ventilation hole 213 along the channel between the cover body peripheral plate 2121 and the air delivery pipe 211. Since the second ventilation hole 213 extends downwardly, the airflow can flow downwardly along the second ventilation hole 213, so that the coal particles in the combustion chamber 11 are fluidized evenly.

[0048] In some embodiments of the present invention, the ratio of the inner diameter of the wind shield peripheral plate 3121 to the inner diameter of the shield body peripheral plate 2121 is equal to the ratio of the diameter of the air guide channel 3111 to the diameter of the air delivery channel 2111 .

[0049] Specifically, through the above-mentioned setting method, it is equivalent to proportionally enlarging the air guide cover 312 and the air guide pipe 311 relative to the air guide cover 212 and the air supply pipe 211, ensuring that the wind cap 21 and the urea sprayer 31 have the same gas flow area, so the flow rate and wind speed of the air flow will not be changed, thereby ensuring the original flue gas flow field.

[0050] like Figure 1 As shown, the present invention further provides a boiler system, which includes a urea solution providing device and the above-mentioned circulating fluidized bed boiler, the urea solution providing device is located outside the boiler body 1, and the urea solution providing device is connected to the urea spraying mechanism 3.

[0051] Specifically, the urea solution providing device is connected to the urea spraying mechanism 3 through a urea delivery pipe. A flow meter 33 and an electric regulating valve 32 may be provided on the urea delivery pipe. The electric regulating valve 32 can adjust the flow of the urea solution in the urea delivery pipe.

[0052] In this embodiment, the boiler system adopts the circulating fluidized bed boiler of the above embodiment, so the above technical effects can also be achieved.

[0053] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above are only preferred implementation methods of the present invention. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of the present invention, they can make several improvements, modifications or changes, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the present invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A circulating fluidized bed boiler, characterized in that: include: A boiler body (1), wherein the boiler body (1) has a combustion chamber (11) inside, a smoke outlet (12) communicating with the combustion chamber (11) is provided at the top of the boiler body (1), a primary air inlet (13) is provided at the bottom of the boiler body (1), the combustion chamber (11) is located between the smoke outlet (12) and the primary air inlet (13), and the combustion chamber (11) includes a dense phase zone (111); an air distribution plate (2), the air distribution plate (2) being installed in the boiler body (1), the air distribution plate (2) being located between the primary air inlet (13) and the dense phase zone (111), and the air distribution plate (2) being provided with a plurality of air caps (21) at intervals for allowing airflow to flow from the primary air inlet (13) into the combustion chamber (11); and A urea spraying mechanism (3), the urea spraying mechanism (3) being mounted on the air distribution plate (2) and vertically facing the central area of ​​the dense phase zone (111); the urea spraying mechanism (3) being used to communicate with a urea solution supply device, and a spraying hole (3132) of the urea spraying mechanism (3) being located above the wind cap (21) so as to be able to spray urea solution into the central area of ​​the dense phase zone (111); and the urea spraying mechanism (3) is also configured to allow airflow to flow from the primary air inlet (13) into the combustion chamber (11).

2. The circulating fluidized bed boiler according to claim 1, characterized in that: The urea spraying mechanism (3) comprises a plurality of urea sprayers (31) distributed at intervals, and the urea sprayers (31) can be connected to the urea solution supply device.

3. The circulating fluidized bed boiler according to claim 2, characterized in that: The urea sprayer (31) comprises an air guide pipe (311), an air guide cover (312) and a liquid delivery pipe (313); The air guide tube (311) is sealed and passes through the air distribution plate (2); the top end of the air guide tube (311) is higher than the top surface of the air distribution plate (2); the bottom end of the air guide tube (311) is flush with the bottom surface of the air distribution plate (2); and the air guide tube (311) has an air guide channel (3111) extending along its axial direction; The wind guide cover (312) comprises a wind cover peripheral plate (3121) and a wind cover top plate (3122); the wind cover peripheral plate (3121) is coaxially sleeved on the outside of the air guide tube (311), and the inner side surface of the wind cover peripheral plate (3121) is radially spaced apart from the outer side surface of the air guide tube (311); the bottom end of the wind cover peripheral plate (3121) is sealedly connected to the top surface of the air distribution plate (2); the wind cover peripheral plate (3121) is provided with a plurality of circumferentially spaced first ventilation holes (3123), and the first ventilation holes (3123) extend obliquely from the air inlet end to the air outlet end thereof from top to bottom; the wind cover top plate (3122) is sealedly connected to the top end of the wind cover peripheral plate (3121), and the wind cover top plate (3122) is vertically spaced apart from the top end of the air guide tube (311); The liquid delivery pipe (313) passes through the air guide channel (3111) of the air guide pipe (311) and the wind shield top plate (3122); the axis of the liquid delivery pipe (313) coincides with the axis of the air guide pipe (311); the outside of the liquid delivery pipe (313) is sealedly connected to the wind shield top plate (3122); the liquid delivery pipe (313) has a liquid channel (3131) extending along its axial direction; the top end of the liquid delivery pipe (313) is located above the wind shield top plate (3122); the top end of the liquid channel (3131) is sealed by a sealing member. The liquid delivery pipe (313) is sealed by a sealing member (314); the liquid delivery pipe (313) is provided with a plurality of spray holes (3132) which are circumferentially spaced and connected to the liquid channel (3131); the spray holes (3132) extend obliquely from the bottom to the top of the liquid inlet end to the liquid outlet end; the spray holes (3132) are located between the top of the liquid delivery pipe (313) and the top plate (3122) of the wind hood; the bottom end of the liquid delivery pipe (313) is located below the bottom surface of the wind distribution plate (2); the bottom end of the liquid delivery pipe (313) can be connected to the urea solution providing device.

4. The circulating fluidized bed boiler according to claim 3, characterized in that: The multiple spray holes (3132) include multiple first spray holes (3133), multiple second spray holes (3134) and multiple third spray holes (3135); the multiple first spray holes (3133) are circumferentially spaced at the same height; the multiple second spray holes (3134) are circumferentially spaced at the same height; the multiple third spray holes (3135) are circumferentially spaced at the same height; the distribution position of the first spray holes (3133) is higher than the distribution position of the second spray holes (3134); the distribution position of the second spray holes (3134) is higher than the distribution position of the third spray holes (3135).

5. The circulating fluidized bed boiler according to claim 4, characterized in that: The distance between the liquid inlet end of the third spray hole (3135) and the top surface of the wind hood top plate (3122) is in the range of 700mm-900mm.

6. The circulating fluidized bed boiler according to claim 4, characterized in that: The sealing member (314) comprises a counterweight block (3141), a connecting rod (3142) and a blocking block (3143); The counterweight block (3141) is provided with a slot (3144), and the slot (3144) is recessed from the bottom surface of the counterweight block (3141) to the top surface of the counterweight block (3141); the top end of the liquid delivery pipe (313) is movably inserted into the slot (3144); The connecting rod (3142) is located in the slot (3144), the top end of the connecting rod (3142) is fixedly connected to the top surface of the slot (3144), the bottom end of the connecting rod (3142) is movably inserted into the top end of the liquid channel (3131), and the axis of the connecting rod (3142) coincides with the axis of the liquid channel (3131); the blocking block (3143) is fixedly connected to the bottom end of the connecting rod (3142), the blocking block (3143) is located in the top end of the liquid channel (3131) and blocks the liquid channel (3131). 31); a first limit block (3136) and a second limit block (3137) fixedly connected to the liquid delivery pipe (313) are provided in the liquid channel (3131); the first limit block (3136) is located above the blocking block (3143), and the second limit block (3137) is located between the spray hole (3132) and the wind shield top plate (3122); the blocking block (3143) can move vertically between the first limit block (3136) and the second limit block (3137) along the liquid channel (3131); When the blocking block (3143) contacts the first limiting block (3136), the first spray hole (3133), the second spray hole (3134) and the third spray hole (3135) are connected to the liquid channel (3131); when the blocking block (3143) contacts the second limiting block (3137), the first spray hole (3133), the second spray hole (3134) and the third spray hole (3135) are blocked by the blocking block (3143).

7. The circulating fluidized bed boiler according to claim 6, characterized in that: The first limiting block (3136) and the second limiting block (3137) are arranged in a ring shape, the inner diameter of the first limiting block (3136) is smaller than the diameter of the blocking block (3143) and larger than the diameter of the connecting rod (3142), and the inner diameter of the second limiting block (3137) is smaller than the diameter of the blocking block (3143).

8. The circulating fluidized bed boiler according to claim 3, characterized in that: The wind cap (21) comprises an air delivery pipe (211) and a flow guide cover (212). The air delivery pipe (211) passes through the air distribution plate (2) in a sealed manner, the top end of the air delivery pipe (211) is higher than the top surface of the air distribution plate (2), the bottom end of the air delivery pipe (211) is flush with the bottom surface of the air distribution plate (2), and the air delivery pipe (211) has an air delivery channel (2111) extending along its axial direction; The air deflector (212) comprises a hood peripheral plate (2121) and a hood top plate (2122); the hood peripheral plate (2121) is coaxially sleeved on the outside of the air supply pipe (211), and the inner side surface of the hood peripheral plate (2121) is spaced apart from the outer side surface of the air supply pipe (211); the bottom end of the hood peripheral plate (2121) is sealedly connected to the top surface of the air distribution plate (2); the hood peripheral plate (2121) is provided with a plurality of circumferentially spaced second ventilation holes (213), and the second ventilation holes (213) extend obliquely from the air inlet end to the air outlet end thereof from top to bottom; the hood top plate (2122) is sealedly connected to the top end of the hood peripheral plate (2121), and the hood top plate (2122) is spaced apart from the top end of the air supply pipe (211).

9. The circulating fluidized bed boiler according to claim 8, characterized in that: The ratio of the inner diameter of the wind shield peripheral plate (3121) to the inner diameter of the shield body peripheral plate (2121) is equal to the ratio of the diameter of the air guide channel (3111) to the diameter of the air delivery channel (2111).

10. A boiler system, characterized in that: It comprises a urea solution providing device and a circulating fluidized bed boiler according to any one of claims 1 to 9, wherein the urea solution providing device is located outside the boiler body (1), and the urea solution providing device is connected to the urea spraying mechanism (3).

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