Ammonia-coal co-combustion turbulent burner for pulverized coal fired boiler

Abstract

The invention relates to the technical field of turbulent combustors, and discloses a pulverized coal fired boiler ammonia-coal co-combustion turbulent combustor which comprises an outer secondary air channel, an inner secondary air channel, a primary air channel and a center air channel which are sequentially arranged from outside to inside, and a pulverized coal concentrator arranged on the periphery of the center air channel in a sleeving mode is arranged in the primary air channel. An ammonia spray gun is further arranged in the primary air channel. Ammonia-doped combustion can be carried out, mixed combustion of ammonia gas and pulverized coal is achieved, ammonia combustion does not generate carbon dioxide, ammonia gas serves as an energy source to replace part of pulverized coal for combustion, carbon dioxide generated by a coal-fired power plant can be effectively reduced, thermal power carbon reduction is facilitated, and safe and stable combustion is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of swirl burners, and more particularly to a swirl burner for a pulverized coal boiler for mixed combustion of ammonia and coal. Background Art

[0002] The combustion of coal will produce a large amount of harmful gases and particulate matter such as carbon dioxide, sulfur oxides, nitrogen oxides and particulate matter, which will have a serious impact on the environment and human health, and aggravate the global climate change and air pollution problems. As a major carbon emitter, thermal power units are facing great pressure to reduce carbon emissions. In order to solve these problems, people began to look for cleaner and more efficient combustion technologies and fuel alternatives. Ammonia has the advantages of high energy density, low liquefaction pressure, and low storage and transportation costs. At the same time, the source of ammonia can be produced by catalytic reaction of nitrogen and hydrogen under high temperature and high pressure conditions. Ammonia coal combustion technology is one of the innovative technologies. It uses ammonia as a fuel to replace traditional coal. The main by-products produced during the combustion process are nitrogen and water vapor. Harmful substances such as carbon dioxide in the emitted gas are greatly reduced, with lower carbon emissions and higher combustion efficiency.

[0003] In the context of flexible peak regulation of coal-fired power units, it is very important to safely and effectively organize the combustion of ammonia and pulverized coal, better realize the ammonia-blended combustion of coal-fired power plants, and develop an ammonia-coal-gas-solid two-phase fuel burner. Summary of the invention

[0004] In view of this, the present invention provides a swirl burner for ammonia-coal mixed combustion in a pulverized coal boiler, which can organize the combustion of ammonia and coal powder to achieve ammonia-mixed combustion in a coal-fired power plant.

[0005] To achieve the above-mentioned purpose, the swirl burner for ammonia-coal mixed combustion in a pulverized coal boiler provided by the present invention comprises an outer secondary air channel, an inner secondary air channel, a primary air channel and a central air channel which are arranged in sequence from the outside to the inside, a pulverized coal concentrator which is sleeved on the outer periphery of the central air channel is provided in the primary air channel, and an ammonia spray gun is also provided in the primary air channel.

[0006] Preferably, the ammonia spray gun is inserted from the rear end of the primary air channel and extends to the rear end of the coal powder concentrator.

[0007] Preferably, the outer secondary air channel is provided with tangential swirl blades, the inner secondary air channel is provided with axial swirl blades, and an inner secondary air expansion port is installed at the outlet of the inner secondary air channel.

[0008] Preferably, a flame stabilizing tooth is provided at the outlet of the primary air channel.

[0009] Preferably, an inner secondary air regulating baffle is provided on the inner secondary air channel, an outer secondary air regulating baffle is provided on the outer secondary air channel, and an ammonia flow valve is provided on the ammonia spray gun.

[0010] Preferably, the number of the ammonia spray guns is one or more, and the multiple ammonia spray guns are arranged along the circumference of the primary air channel.

[0011] Preferably, a replaceable ammonia nozzle is provided at the front end of the ammonia spray gun.

[0012] It can be known from the above technical scheme that, compared with the prior art, the swirl burner for ammonia-coal mixed combustion of a pulverized coal boiler disclosed in the present invention can perform ammonia-mixed combustion to achieve mixed combustion of ammonia and pulverized coal. Ammonia combustion does not produce carbon dioxide. Ammonia is used as an energy source to replace part of the pulverized coal for combustion, which can effectively reduce the carbon dioxide produced by coal-fired power plants, help reduce carbon emissions in thermal power plants, and achieve safe and stable combustion. Among them, ammonia comes out of the nozzle and mixes with pulverized coal in the primary air duct, so that an ammonia-rich combustion zone is formed at the primary air outlet, and the internal secondary air of the swirl forms a recirculation zone, which sucks in high-temperature flue gas, heats pulverized coal and ammonia fuel, and helps ignition and combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0014] Figure 1 It is an axial cross-sectional perspective view of a swirl burner of the present invention; Figure 2 It is an axial cross-sectional plan view of the swirl burner of the present invention.

[0015] Explanation of the reference numerals: central air channel -1, ammonia spray gun -2, primary air channel -3, ammonia nozzle -4, inner secondary air regulating baffle -5, coal powder concentrator -6, axial swirl blade -7, inner secondary air channel -8, outer secondary air regulating baffle -9, tangential swirl blade -10, outer secondary air channel -11, combustion stabilizing tooth -12. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of an exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Please see attached Figure 1-2 , which is a swirl burner for ammonia-coal mixed combustion in a pulverized coal boiler disclosed by the present invention.

[0018] like Figure 1-2 As shown, the swirl burner for ammonia-coal mixed combustion in a pulverized coal boiler provided by the present invention has a layered surrounding structure, including a central air channel 1, an ammonia spray gun 2, a primary air channel 3, an inner secondary air channel 8, and an outer secondary air channel 11.

[0019] The outer secondary air channel 11, the inner secondary air channel 8, the primary air channel 3 and the central air channel 1 are surrounded and arranged in sequence from the outside to the inside. The outer secondary air channel 8 is provided with a tangential swirl blade 10, the inner secondary air channel 8 is provided with an axial swirl blade 7, the inner secondary air channel 8 is provided with an inner secondary air expansion port, the outlet of the primary air channel 3 is provided with a combustion stabilizing tooth 12, the inner secondary air channel 8 is provided with an inner secondary air regulating baffle 5, the outer secondary air channel 11 is provided with an outer secondary air regulating baffle 9, the primary air channel 3 is provided with a coal powder concentrator 6, and the outer coal powder concentrator 6 is sleeved on the outer periphery of the central air channel 1.

[0020] In order to further optimize the above technical solution, at least one ammonia spray gun 2 is provided in the primary air channel 3, and an ammonia flow valve is provided on the ammonia spray gun 2. The ammonia spray gun 2 passes through the flange and is inserted from the rear end of the primary air channel 3 and extends to the rear end of the pulverized coal concentrator 6. A replaceable ammonia nozzle 4 is installed at the front end of the ammonia spray gun 2.

[0021] The number of ammonia spray guns 2 in this embodiment is 3. Those skilled in the art will appreciate that ammonia can be supplied by a corresponding number of spray guns according to the amount of fuel. The ammonia spray guns 2 are arranged circumferentially in the primary air channel 3 along the primary air direction.

[0022] When this embodiment is used, the primary air carries the coal powder into the primary channel 3, and the ammonia enters the primary channel 3 through the ammonia spray gun 2. During this process, the flow rate of ammonia can be controlled by a flow valve, thereby controlling the ammonia-coal equivalence ratio. The ammonia is atomized in the ammonia nozzle 4 through the ammonia spray gun 2, and the ammonia is mixed with the primary air powder. The primary air powder / ammonia mixture passes through the coal powder concentrator 6 in the primary air channel 3 to achieve a radial thick and thin separation effect of the coal powder. The primary air powder / ammonia mixture forms an ammonia rich combustion zone at the primary air outlet, and the internal secondary air of the swirl forms a recirculation zone, which draws in high-temperature flue gas, heats the coal powder and ammonia fuel, and helps ignition and combustion.

[0023] In this embodiment, a central wind is provided in the central wind channel 1, and the distance between the ignition point and the burner nozzle is adjusted by adjusting the wind speed of the central wind.

[0024] In this embodiment, the inlet of the inner secondary air and the outer secondary air is provided with an air inlet adjustment baffle, which can realize air volume adjustment. The axial swirl blades 7 are arranged in the inner secondary air channel 8, and the tangential swirl blades 10 are arranged in the outer secondary air channel 11, which can improve the swirl intensity of the secondary air. In some embodiments, the shape and number of the swirl blades in the cyclone can be changed according to actual needs to improve the swirl effect. The inner secondary air and the outer secondary air rotate into the furnace, and the radial thick and thin separation of the coal powder at the primary air outlet realizes graded combustion, which is conducive to reducing the emission of nitrogen oxides.

[0025] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A swirl burner for ammonia-coal mixed combustion in a pulverized coal boiler, with a layered surrounding structure, characterized in that: The invention comprises an outer secondary air channel (11), an inner secondary air channel (8), a primary air channel (3) and a central air channel (1) which are arranged in sequence from the outside to the inside. A pulverized coal concentrator (6) which is sleeved on the outer periphery of the central air channel (1) is arranged in the primary air channel (3). An ammonia spray gun (2) is also arranged in the primary air channel (3).

2. The swirl burner for ammonia-coal mixed combustion of pulverized coal boiler according to claim 1, characterized in that: The ammonia spray gun (2) is inserted from the rear end of the primary air channel (3) and extends to the rear end of the pulverized coal concentrator (6).

3. The swirl burner for ammonia-coal mixed combustion of pulverized coal boiler according to claim 1, characterized in that: The outer secondary air channel (11) is provided with a tangential swirl blade (10), the inner secondary air channel (8) is provided with an axial swirl blade (7), and an inner secondary air expansion port is installed at the outlet of the inner secondary air channel (8).

4. The swirl burner for ammonia-coal mixed combustion of pulverized coal boiler according to claim 1, characterized in that: A flame stabilizing tooth (12) is provided at the outlet of the primary air channel (3).

5. The swirl burner for ammonia-coal mixed combustion of pulverized coal boiler according to claim 1, characterized in that: The inner secondary air passage (8) is provided with an inner secondary air regulating baffle (5), the outer secondary air passage (11) is provided with an outer secondary air regulating baffle (9), and the ammonia spray gun (2) is provided with an ammonia flow valve.

6. The swirl burner for ammonia-coal mixed combustion in a pulverized coal boiler according to claim 1, characterized in that: The number of the ammonia spray guns (2) is one or more, and the plurality of ammonia spray guns (2) are arranged along the circumference of the primary air channel (3).

7. The swirl burner for ammonia-coal mixed combustion in a pulverized coal boiler according to claim 1, characterized in that: A replaceable ammonia nozzle (4) is provided at the front end of the ammonia spray gun (2).

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