After-air nozzle for two-stage combustion boiler, and a two-stage combustion boiler, boiler and combustion method using the same
IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
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출원번호 |
UP-0263035
(2005-11-01)
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등록번호 |
US-7681508
(2010-04-21)
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우선권정보 |
JP-2004-318996(2004-11-02); JP-2004-356394(2004-12-09) |
발명자
/ 주소 |
- Taniguchi, Masayuki
- Yamamoto, Kenji
- Okazaki, Hirofumi
- Yasuda, Kazumi
- Kiyama, Kenji
- Yano, Takanori
- Baba, Akira
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
2 인용 특허 :
2 |
초록
▼
An after-air nozzle capable of reducing NOx and CO and a boiler equipped with such a nozzle are provided The after-air nozzle has a vena contracta such that an outside diameter of a flow passage diminishes towards the air-jetting port which supplies air to a boiler, and a changing apparatus changes
An after-air nozzle capable of reducing NOx and CO and a boiler equipped with such a nozzle are provided The after-air nozzle has a vena contracta such that an outside diameter of a flow passage diminishes towards the air-jetting port which supplies air to a boiler, and a changing apparatus changes a flow passage cross-sectional area of the vena contracta. A method of use of such an after-air nozzle and a boiler so equipped is also provided.
대표청구항
▼
What is claimed is: 1. An after-air nozzle for a two-stage combustion boiler, comprising: a windbox outer casing for surrounding an outside of an after-air nozzle, an opening of the windbox provided on the windbox outer casing to flow air for combustion into the after-air nozzle; a vena contracta a
What is claimed is: 1. An after-air nozzle for a two-stage combustion boiler, comprising: a windbox outer casing for surrounding an outside of an after-air nozzle, an opening of the windbox provided on the windbox outer casing to flow air for combustion into the after-air nozzle; a vena contracta adapted such that an outside diameter of a flow passage diminishes towards an air-jetting port which supplies air to the boiler; and a changing apparatus of a flow passage cross-sectional area of the vena contracta, wherein air for combustion flows into the after-air nozzle from the opening of the window, streams through the changing apparatus of the flow passage cross-sectional area and jets into the boiler from the air-jetting port, the changing apparatus of the flow passage cross-section area is provided with a member which defines a minimum flow passage area of the vena contracta in the after-air nozzle, the after-air nozzle further comprising a first slide member for moving the changing apparatus of the flow passage cross-sectional area in a direction of a flow passage so that the flow passage area of the vena contracta can be changed, and a second slide member provided on the windbox outer casing for changing an area of the opening of the windbox for air flowing into the after-air nozzle. 2. The after-air nozzle according to claim 1, wherein the member defining a minimum flow passage area of the vena contracta is adapted to progressively diminish in outside diameter towards the air-jetting port. 3. The after-air nozzle according to claim 1, wherein, when a flow direction of the air that flows inside the after-air nozzle is taken as a reference, a moving range of the member defining a minimum flow passage area of the vena contracta begins at the place where a front end of the member is positioned closer to an upstream side of the flow direction than to a starting position of the vena contracta, and ends at the place where the front end of the member is positioned closer to a downstream side of the flow direction than to the starting position of the vena contracta. 4. A two-stage combustion boiler, comprising; a furnace for generating a steam by thermal energy of a combustion gas by burning a fuel and air; a burner provided upstream with respect to a flow direction of the gas in the furnace, wherein the burner burns the fuel under conditions short of air; and an after-air nozzle provided downstream with respect to the flow direction of the gas in the furnace, and downstream with respect to the burner, wherein the nozzle supplies the air required for achieving a complete combustion of the combustion gas; wherein the after-air nozzle according to claim 1 having is disposed at a plurality of positions in the furnace. 5. A boiler adapted to achieve two-stage combustion by equipping a furnace wall with a burner which burns a fuel in a state of air shortage, and with an after-air nozzle by which a complete combustion of the combustion gas generated by the burner is conducted downstream with respect to a flow direction of the combustion gas, the boiler further comprising: a main after-air nozzle formed at the uppermost stream end and a subsidiary after-air nozzle formed at the downstream with the after-air nozzle disposed in a plural-stage form in the flow direction of the combustion gas, wherein the main after-air nozzle and the subsidiary after-air nozzle are used as the after-air nozzle according to claim 1. 6. The boiler according to claim 5, wherein the main after-air nozzle includes a primary nozzle, a secondary nozzle provided externally thereto, and a tertiary nozzle provided further externally thereto, and wherein the tertiary nozzle is oriented towards a nozzle central axis, and an air stream jetted from the tertiary nozzle has a center-directional velocity component. 7. The boiler according to claim 6, wherein the primary nozzle and the secondary nozzle each supplies a rectilinear stream or swirling stream of air. 8. The boiler according to claim 5, further including: an air volume controller to control the total amount of air supplied to the main after-air nozzle and the subsidiary after-air nozzle; and an air ratio controller to control a ratio between the amount of air supplied to the main after-air nozzle and the amount of air supplied to the other subsidiary after-air nozzles. 9. The boiler according to claim 5, wherein the after-air nozzle is provided in a two-stage form. 10. The boiler according to claim 5, wherein the main after-air nozzle and the subsidiary after-air nozzle are each arranged at plural positions opposed to a furnace front wall and a furnace rear wall. 11. The boiler according to claim 10, wherein each of the subsidiary after-air nozzles is arranged directly above each of the main after-air nozzles. 12. The boiler according to claim 10, wherein each of the subsidiary after-air nozzles is arranged downstream between the main after-air nozzles. 13. The boiler according to claim 10, wherein the subsidiary after-air nozzles are each arranged at sidewalls of the boiler. 14. A method of combustion in a boiler adapted to achieve two-stage combustion by equipping a furnace wall with a burner to burn a fuel in a state of air shortage, and with an after-air nozzle having a main after-air nozzle and a subsidiary after-air nozzle to burn a complete combustion of the combustion gas generated by the burner is conducted downstream with respect to a flow direction of the combustion gas, the main after-air nozzle comprising a windbox outer casing for surrounding an outside of an after-air nozzle, an opening of the windbox provided on the windbox outer casing to flow air for combustion into the after-air nozzle, a vena contracta adapted such that an outside diameter of a flow passage diminishes towards an air-jetting port which supplies air to the boiler, a changing apparatus of a flow passage cross-sectional area of the vena contracta provided with a member which defines a minimum flow passage area of the vena contracta in the after-air nozzle, and the after-air nozzle further comprising a first slide member for moving the changing apparatus of the flow passage cross-sectional area in a direction of a flow passage, and a second slide member provided on the windbox outer casing for changing an area of the opening of the windbox, wherein air for combustion flows into the after-air nozzle from the opening of the windbox, streams through the changing apparatus of the flow passage cross-sectional area and jets into the boiler from the air-jetting port, the combustion method comprising the steps of: adjusting an amount of air flowing into the main after-air nozzle formed at the uppermost stream end with the after-air nozzle and conducting a two-stage combustion of the fuel in the boiler having the vena contracta formed in the main after-air nozzle by moving the first slide member to move the changing apparatus of a flow passage cross-sectional area in the main after-air nozzle so that the flow passage area of the vena contracta can be changed; and adjusting an area of the opening of the windbox for air flowing into the main after-air nozzle by moving the second slide member, so that a total amount of air flowing into the main after-air nozzle can be maintained constant during the two-stage combustion.
이 특허에 인용된 특허 (2)
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McCartney Michael S. (Bloomfield CT) Chadshay Roman (Windsor CT) Erlacher Richard F. (Simsbury CT), Nozzle tip for pulverized coal burner.
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Garcia-Mallol Juan Antonio, Over-fire air control system for a pulverized solid fuel furnace.
이 특허를 인용한 특허 (2)
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Cheng, Changye; Yang, Jiaju; Li, Yi; Cui, Xingyuan; Zhang, Chaoqun; Gong, Zeru; Zhang, Guangquan; Zhang, Yubin; Liu, Peng, Pulverized coal concentrator and pulverized coal burner including the concentrator.
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Kamikawa, Yuki; Taniguchi, Masayuki; Orita, Hisayuki; Kobayashi, Hironobu; Baba, Akira; Mine, Toshihiko; Nomura, Shinichirou; Ooyatsu, Noriyuki; Tadakuma, Satoshi; Yoshizako, Hidehisa; Kanemoto, Hiroaki; Kuramashi, Kouji; Orii, Akihito; Tsuda, Shinji; Okazaki, Hirofumi; Yano, Takanori; Shimohira, Katsumi, Pulverized coal-fired boiler and pulverized coal burning method.
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