CN201521952U - A multi-stage secondary air supply device sandwiching a partition wall in a circulating fluidized bed - Google Patents

Abstract

The utility model relates to a multi-stage secondary air air supply device sandwiching a partition wall in a circulating fluidized bed. It has a furnace top secondary air box, at least one secondary air pipe and a furnace bottom secondary air box, the secondary air pipe is connected to the furnace top secondary air box and the furnace bottom secondary air box, and the secondary air pipe is arranged in the middle partition of the furnace In the interval of the working medium circulation pipes of the tube panel of the wall, each secondary air pipe has a plurality of secondary air nozzles on both sides of the middle partition wall at different heights of the furnace. The utility model arranges the secondary air pipe in the interval of the working fluid flow pipe of the tube panel of the middle partition wall to supplement and supply the secondary air to the furnace, and the secondary air port can be set up on the secondary air pipe along the height of the furnace according to the need, so as to realize multiple Level air supply, improve the distribution of oxygen concentration field in the furnace combustion center area, and improve the combustion efficiency of the boiler. The utility model directly supplements the secondary air required for combustion from the combustion center area of the boiler furnace, and the effect is direct and reliable. At the same time, it is attached to the middle partition wall, has a simple structure, and is convenient to manufacture and install.

Description

A multi-stage secondary air supply device sandwiching a partition wall in a circulating fluidized bed

technical field

The utility model relates to a multi-stage secondary air air supply device sandwiching a partition wall in a circulating fluidized bed.

Background technique

With the development of circulating fluidized bed technology, the issue of range and diffusion of secondary air in fluidized bed boilers has attracted more and more attention. Especially as the capacity of circulating fluidized bed boilers continues to increase, the cross-section of the furnace continues to increase, and the height of the furnace continues to increase. It is difficult for the secondary air to reach the central area of the furnace, which makes the central area of the furnace in a state of severe hypoxia. Tests have proved that the lack of oxygen in the furnace center is common in large circulating fluidized bed boilers. Due to the lack of oxygen in the large area of the furnace center, fuel combustion is insufficient, especially the boiler fly ash is high in combustibles, which reduces the combustion efficiency of the boiler. Therefore, with the development of large-scale circulating fluidized bed, the key problem that needs to be solved is the lack of secondary air in the combustion center area of the furnace.

The applicant Harbin Institute of Technology proposed a fluidized bed combustion device (patent publication number CN 101196295A) for a wall-center composite supply of secondary air. The counterflow secondary air column combined with air supply extending into the combustion center area of the furnace supplements the air needed for combustion in the central area of the furnace. But this device is not suitable for the structure of large-scale circulating fluidized bed boiler, and the underpants leg structure and the partition wall all hinder the application of this device.

The applicant Xi'an Thermal Engineering Research Institute Co., Ltd. proposed a secondary air supply method and device for an inner concave circulating fluidized bed boiler (patent publication number CN 101225954A). The furnace is recessed so that the secondary air supply nozzle is closer to the center of the furnace to supply air to the furnace, thereby improving the distribution of the oxygen concentration field in the combustion center area of the furnace and eliminating the phenomenon of oxygen deficiency in the center area of the furnace. However, this method has a complicated structure, changes the structure of the furnace, and directly affects the material flow inside the furnace.

The applicant Foster Wade Energy Co., Ltd. proposed a "pants" type furnace layout structure (patent publication number CN 1270664A), which uses the middle partition wall to form a secondary air chamber for air supply, and at the same time forms two combustion chambers at the bottom of the furnace. Chambers and combustion chambers are either independent or connected by passages. This structure is widely used, but it is difficult to replenish the gas volume in the upper part of the furnace, and the structure is relatively complicated.

Contents of the invention

The purpose of this utility model is to provide a partition wall sandwich multi-stage secondary air supply device for circulating fluidized bed boilers in view of the above-mentioned shortcomings in the prior art.

The partition wall sandwich multi-stage secondary air supply device in the circulating fluidized bed boiler has a secondary air box on the furnace top, at least one secondary air pipe and a secondary air box on the furnace bottom. The secondary air pipe is connected to the secondary air box on the furnace top and the furnace Bottom secondary bellows, the furnace is provided with a middle partition wall, and the secondary air pipe is arranged in the interval of the working fluid flow pipe of the tube panel in the middle partition wall of the furnace, and the working fluid in the tube panel working medium flow tube is water, A mixture of steam or soda, each secondary air pipe has multiple secondary air nozzles on both sides of the middle partition wall at different heights of the furnace.

The included angle between the axis of the secondary air nozzle and the horizontal line is within ±45°. The ratio a/A of the air flow area a of the secondary air nozzle to the air flow area A of the secondary air pipe is 1.6×10 ^-3 -3.25. A wind cap is arranged on the secondary air nozzle, and the wind cap is a side arrow type wind cap or a bell type wind cap. The multiple secondary air nozzles on the secondary air pipe can be arranged in parallel or alternately. A refractory and wear-resistant material layer is laid on the secondary air pipe.

The utility model has the following beneficial effects: the utility model is a multi-stage secondary air supply device sandwiching a partition wall in a circulating fluidized bed boiler. The utility model utilizes the middle partition wall existing in the furnace of a large-scale circulating fluidized bed boiler to supplement and supply the secondary air by arranging a secondary air pipe in the middle partition wall tube panel working medium circulation pipe interval, and at the same time, on the secondary air pipe Secondary air outlets can be opened as needed to realize multi-stage air supply along the height of the furnace. Through this sandwich-type multi-stage air supply system in the middle partition wall, the air required for combustion at different heights in the combustion center area of the boiler furnace is supplemented, improving the The distribution of oxygen concentration field in the combustion area solves the phenomenon of oxygen deficiency in the hearth center of large circulating fluidized bed boilers with increasing furnace area and height, promotes the full mixing and reaction of gas-solid two-phase in the boiler, and improves the combustion efficiency of the boiler. At the same time, the air supply method and device of the utility model have simple structure and obvious effect, and can meet the requirements of large circulating fluidized bed.

Description of drawings

Figure 1 is a structural schematic diagram of a multi-stage secondary air supply device with a partition wall sandwiched in a single furnace circulating fluidized bed boiler;

Fig. 2 is a structural schematic diagram of a partition wall sandwich multi-stage secondary air supply device in a pant-type furnace circulating fluidized bed boiler;

Fig. 3 is the structural schematic view of A to the embodiment 1 of the utility model;

Fig. 4 is the structural schematic diagram of A to the embodiment 2 of the utility model;

Fig. 5 is a structural schematic view of A direction of Embodiment 3 of the present utility model;

Fig. 6 is a structural schematic diagram of A direction of Embodiment 4 of the present utility model;

Fig. 7 is a structural schematic diagram of A direction of Embodiment 5 of the present utility model;

In the figure, the furnace top secondary air box 1, the secondary air pipe 2, the furnace bottom secondary air box 3, the furnace 4, the middle partition wall 5, the tube panel, the working fluid flow pipe 6, and the secondary air nozzle 7.

Detailed ways

As shown in Figures 1 and 2, the partition wall sandwich multi-stage secondary air supply device in the circulating fluidized bed boiler has a furnace top secondary air box 1, at least one secondary air pipe 2 and a furnace bottom secondary air box 3, two The secondary air duct 2 is connected to the secondary air box 1 on the top of the furnace and the secondary air box 3 at the bottom of the furnace. The furnace 4 is provided with a middle partition wall 5, and the secondary air pipe 2 is arranged in the tube panel working medium circulation pipe of the middle partition wall 5 In the interval of 6, the working medium in the working medium circulation pipe of the tube panel is a mixture of water, steam or soda water, and each secondary air pipe 2 is opened with multiple secondary air pipes 2 at different heights of the furnace toward the two sides of the middle partition wall. Wind spout7.

The secondary air pipe 2 can be sandwiched by selecting several intervals between the tube panel working fluid flow pipes 6 according to the structure of the partition wall 5 and the air supply requirements. The included angle between the axis of the secondary air nozzle 7 and the horizontal line is within ±45°. The ratio a/A of the air flow area a of the secondary air nozzle 7 to the air flow area A of the secondary air pipe 2 is 1.6×10 ⁻³ to 3.25. A wind cap is arranged on the secondary air nozzle 7, and the wind cap is a side arrow type wind cap or a bell type wind cap. The multiple secondary air nozzles 7 on the secondary air pipe 2 can be arranged in parallel or staggered. A fire-resistant and wear-resistant material layer is laid on the secondary air duct 2 .

Embodiment 1: As shown in Figure 3, the partition wall sandwich multi-stage secondary air supply device in the circulating fluidized bed boiler has a furnace top secondary air box 1, at least one secondary air pipe 2 and a furnace bottom secondary air box 3 , the secondary air duct 2 is connected to the furnace top secondary air box 1 and the furnace bottom secondary air box 3, the furnace 4 is provided with a middle partition wall 5, and the secondary air pipe 2 is arranged on the tube screen working medium of the middle partition wall 5 In the interval of the circulation pipe 6, the working medium in the working medium circulation pipe of the tube panel is a mixture of water, steam or soda water, and each secondary air pipe 2 is opened with a plurality of secondary air pipes at a suitable height toward both sides of the middle partition wall. Secondary air nozzle 7. The included angle between the axis of the secondary air nozzle 7 and the horizontal line is within ±45°. The ratio a/A of the air flow area a of the secondary air nozzle 7 to the air flow area A of the secondary air pipe 2 is 1.6×10 ⁻³ to 3.25. The multiple secondary air nozzles 7 on the secondary air pipe 2 can be arranged in parallel or staggered. A fire-resistant and wear-resistant material layer is laid on the secondary air duct 2 .

Embodiment 2: As shown in FIG. 4 , each secondary air duct 2 is provided with multiple secondary air nozzles 7 at several different heights toward both sides of the middle partition wall according to the air supply requirements. The included angle between the axis of the secondary air nozzle 7 and the horizontal line is within ±45°. The ratio a/A of the air flow area a of the secondary air nozzle 7 to the air flow area A of the secondary air pipe 2 is 1.6×10 ⁻³ to 3.25. The multiple secondary air nozzles 7 on the secondary air pipe 2 can be arranged in parallel or staggered. A fire-resistant and wear-resistant material layer is laid on the secondary air duct 2 .

Embodiment 3: As shown in FIG. 5 , each secondary air duct 2 is provided with a plurality of secondary air nozzles 7 on both sides of the middle partition wall at a suitable height. The included angle between the axis of the secondary air nozzle 7 and the horizontal line is within ±45°. The ratio a/A of the air flow area a of the secondary air nozzle 7 to the air flow area A of the secondary air pipe 2 is 1.6×10 ⁻³ to 3.25. A wind cap is arranged on the secondary air nozzle 7, and the wind cap is a side arrow type wind cap. The multiple secondary air nozzles 7 on the secondary air pipe 2 can be arranged in parallel or staggered. A fire-resistant and wear-resistant material layer is laid on the secondary air duct 2 .

Embodiment 4: As shown in FIG. 6 , each secondary air duct 2 is provided with a plurality of secondary air nozzles 7 on both sides of the middle partition wall at a suitable height. The included angle between the axis of the secondary air nozzle 7 and the horizontal line is within ±45°. The ratio a/A of the air flow area a of the secondary air nozzle 7 to the air flow area A of the secondary air pipe 2 is 1.6×10 ⁻³ to 3.25. A wind cap is arranged on the secondary air nozzle 7, and the wind cap is a side bell type wind cap. The multiple secondary air nozzles 7 on the secondary air pipe 2 can be arranged in parallel or staggered. A fire-resistant and wear-resistant material layer is laid on the secondary air duct 2 .

Embodiment 5: Each secondary air pipe 2 is provided with a plurality of secondary air nozzles 7 at a suitable height toward both sides of the middle partition wall. The secondary air pipe 2 can be sandwiched by selecting several intervals between the tube panel working fluid flow pipes 6 according to the structure of the partition wall 5 and the air supply requirements. The included angle between the axis of the secondary air nozzle 7 and the horizontal line is within ±45°. The ratio a/A of the air flow area a of the secondary air nozzle 7 to the air flow area A of the secondary air pipe 2 is 1.6×10 ⁻³ to 3.25. The multiple secondary air nozzles 7 on the secondary air pipe 2 can be arranged in parallel or staggered. A fire-resistant and wear-resistant material layer is laid on the secondary air duct 2 .

Claims (6)

1. A partition wall sandwich multi-stage secondary air supply device for a circulating fluidized bed boiler, characterized in that it has a furnace top secondary air box (1), at least one secondary air pipe (2) and furnace bottom two The secondary air box (3), the secondary air pipe (2) is connected to the furnace top secondary air box (1) and the furnace bottom secondary air box (3), the furnace (4) is provided with a middle partition wall (5), and the secondary The air pipes (2) are arranged in the interval of the tube panel working medium circulation tubes (6) of the middle partition wall (5), and the working medium in the tube panel working medium circulation tubes is a mixture of water, steam or steam water, each two The secondary air pipe (2) is provided with a plurality of secondary air spouts (7) at different heights of the furnace towards both sides of the middle partition wall. 2. The partition wall sandwich multi-stage secondary air supply device according to claim 1, characterized in that the angle between the axis of the secondary air nozzle (7) and the horizontal line is within ±45°. 3. The intermediate partition wall sandwich multi-stage secondary air supply device according to claim 1, characterized in that the air flow area a of the secondary air nozzle (7) communicates with the secondary air pipe (2) The ratio a/A of the area A is 1.6×10 ^-3 to 3.25. 4. The intermediate partition wall sandwich multi-stage secondary air supply device according to claim 1, characterized in that a hood is arranged on the secondary air nozzle (7), and the hood is a side arrow type hood or bell type hood. 5. The intermediate partition wall sandwich multi-stage secondary air supply device according to claim 1, characterized in that a plurality of secondary air nozzles (7) on the secondary air pipe (2) can be parallel or Staggered arrangement. 6. The partition wall sandwich multi-stage secondary air supply device according to claim 1, characterized in that a fire-resistant and wear-resistant material layer is laid on the secondary air pipe (2).

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