Premixed low-nitrogen gas boiler

Patent metadata

Field	Value
Publication number	US-11859867-B2
Application number	US-202218053776-A
Country	US
Kind code	B2
Filing date	Nov 9, 2022
Priority date	Apr 29, 2022
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

A premixed low-nitrogen gas boiler is provided, which includes a reversed flow-swirl mixer being opposite mixing of natural gas and air. A flow deflector is arranged at a gas mixture outlet of the reversed flow-swirl mixer. An upper flow equalizing plate and a lower flow equalizing plate are arranged below the flow deflector, the upper flow equalizing plate is positioned above the lower flow equalizing plate, and a channel for enhancing mixing of gas mixture is formed between the upper flow equalizing plate and the lower flow equalizing plate. A comb-shaped water-cooled burner is arranged at the rear end of the lower flow equalizing plate, a combustion chamber is arranged at the rear end of the comb-shaped water-cooled burner, hearth tube bundles are arranged in a ladder-shaped convergent hearth, and the hearth tube bundles form an inner loop with a working medium water-steam mixture in a hearth water tank.

First claim

What is claimed is:

1. A premixed low-nitrogen gas boiler, comprising a reversed flow-swirl mixer ( 1 ), a flow deflector ( 2 ), an upper flow equalizing plate ( 3 ), a lower flow equalizing plate ( 4 ), a comb-shaped water-cooled burner ( 5 ), a combustion chamber ( 6 ), hearth tube bundles ( 7 ), a ladder-shaped convergent hearth ( 8 ), and an exhaust port ( 10 );
the reversed flow-swirl mixer ( 1 ) is capable of opposite mixing of natural gas and air, the flow deflector ( 2 ) is arranged at a gas mixture outlet of the reversed flow-swirl mixer ( 1 ), the upper flow equalizing plate ( 3 ) and the lower flow equalizing plate ( 4 ) are arranged below the flow deflector ( 2 ), the upper flow equalizing plate ( 3 ) is located above the lower flow equalizing plate ( 4 ), and a channel for enhancing mixing of gas mixture is formed between the upper flow equalizing plate ( 3 ) and the lower flow equalizing plate ( 4 ); the comb-shaped water-cooled burner ( 5 ) is arranged at a rear end of the lower flow equalizing plate ( 4 ), the combustion chamber ( 6 ) is arranged at a rear end of the comb-shaped water-cooled burner ( 5 ), the hearth tube bundles ( 7 ) are arranged in the ladder-shaped convergent hearth ( 8 ), and the hearth tube bundles ( 7 ) form an inner loop with a working medium water-steam mixture in a hearth water tank ( 9 ); and
wherein the reversed flow-swirl mixer ( 1 ) comprises inner side convergent air-swirl vanes ( 1 b ) arranged at an air inlet and outer side divergent air-swirl vanes ( 1 a ) which are arranged at the air inlet, and gas swirl vanes ( 1 c ) which are arranged at the gas mixture outlet and is provided with a swirl channel, the opposite mixing of swirls of the natural gas and the air is performed between an air-swirl outlet and a natural gas swirl outlet; and the inner side convergent air-swirl vanes ( 1 b ) are fixed to the reversed flow-swirl mixer ( 1 ) through wrapping and clamping of the outer side divergent air-swirl vanes ( 1 a ).

2. The premixed low-nitrogen gas boiler according to claim 1 , wherein the flow deflector ( 2 ) is of two layer structure and is divided into an inner side portion, a middle side portion and an outer side portion, the inner side portion has a radius of R 1 , the middle side portion has a radius of R 2 , and the outer side portion has a radius of R 3 ; and the flow deflector ( 2 ) that is of two layer structure is coaxially arranged to trisect a flow area of the flow deflector ( 2 ), such that, R 3 =3R 1 and R 2 =2R 1 .

3. The premixed low-nitrogen gas boiler according to claim 1 , wherein the upper flow equalizing plate ( 3 ) and the lower flow equalizing plate ( 4 ) are both provided with circular holes distributed in a staggered manner.

4. The premixed low-nitrogen gas boiler according to claim 1 , wherein the comb-shaped water-cooled burner ( 5 ) comprises a plurality of comb-shaped water-cooling modules ( 5 b ), both sides of each of the comb-shaped water-cooling modules ( 5 b ) are of a comb shape, and each of Y-shaped airflow channels ( 5 c ) is formed by two of the comb-shaped water-cooling modules ( 5 b ) which are dense and parallel.

5. The premixed low-nitrogen gas boiler according to claim 4 , wherein an inlet of each of the Y-shaped airflow channels ( 5 c ) is a flat rectangular, an outlet of each of the Y-shaped airflow channels is a divergent channel, and a spiral ring rib ( 5 d ) is arranged in an outlet elliptical swirl channel; the two of the comb-shaped water-cooling modules ( 5 b ) are connected by means of a flow equalizing partition plate ( 5 e ); and a plurality of rows of the hearth tube bundles ( 7 ) are arranged in the ladder-shaped convergent hearth ( 8 ) at a front end of the exhaust port ( 10 ), and a number of the plurality of rows of the hearth tube bundles ( 7 ) is reduced row by row.

6. The premixed low-nitrogen gas boiler according to claim 4 , wherein an inlet of each of the Y-shaped airflow channel ( 5 c ) is of a flat rectangular, and an outlet of each of the Y-shaped airflow channel is a rectangular channel; the flow equalizing partition plate ( 5 e ) is installed at a front end of an inlet of the comb-shaped water-cooled burner ( 5 ), and the gas mixture is fed into the comb-shaped water-cooled burner ( 5 ) to play a secondary anti-backfire role after being uniformly mixed for a second time.

7. The premixed low-nitrogen gas boiler according to claim 1 , wherein a row of combustion chamber water-cooling tube bundles ( 6 a ) is arranged on a central axial plane of an outlet of the comb-shaped water-cooled burner ( 5 ) to separate the combustion chamber ( 6 ) into double combustion chambers.

8. The premixed low-nitrogen gas boiler according to claim 1 , wherein cooling water from both the comb-shaped water-cooled combustor ( 5 ) and the combustion chamber ( 6 ) is mixed in a water collecting tank ( 11 ) and discharged from an outlet water tank ( 12 ) by means of an outer loop heat exchanger ( 9 a ).

9. The premixed low-nitrogen gas boiler according to claim 1 , wherein a fixed included angle θ is between a wall surface of the ladder-shaped convergent hearth ( 8 ) and a flue gas flowing direction, and the fixed included angle is greater than 0 degrees and less than 90 degrees; and
the hearth tube bundles ( 7 ) in the hearth water tank ( 9 ) is capable of being in a vacuum state, a normal pressure state or a pressure-bearing state.

Assignees

• Univ Xi An Jiaotong
• Henan Yuanda Boiler Corp Ltd

Inventors

• Niu Yanqing
• Tian Mao
• Zhao Jun
• Liu Hongzhong

Classifications

• F24H1/40 Primary

  with water tube or tubes · CPC title

• F23D14/02

  Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone · CPC title

• F23D14/24

  at least one of the fluids being submitted to a swirling motion · CPC title

• F23D14/62

  Mixing devices; Mixing tubes · CPC title

• F23D14/70

  Baffles or like flow-disturbing devices · CPC title