CN100387902C - Arrangement of the secondary burn-off air in the new third area of the wall-type combustion boiler - Google Patents

Abstract

The invention discloses a split arrangement method of a new three-zone burner of a wall-type combustion boiler. The combustion process in the furnace is divided into three zones through the control of the excess air coefficient of the original burner, the stable combustion zone, and the combustion and reduction zone. and burnout zone; through the arrangement of the burnout air on the side wall of the combustion and reduction zone in time to supplement the combustion air in this zone, the deep low-oxygen and low-temperature combustion of the initial pulverized coal flow and the deep fuel staged combustion in the combustion and reduction zone, successfully solved the problem The shortcomings of the existing low NOx combustion technology in denitrification are poor, and the supplementary method of the secondary overburning air (side wall overburning air and top overburning air) greatly reduces the impact of the new third zone secondary overburning air on combustion efficiency , thus successfully solving the problem that the denitrification effect and combustion efficiency of the existing NOx combustion technology cannot be balanced, and it is a burner arrangement method with a better denitrification effect.

Description

Arrangement of the secondary burn-off air in the new third area of the wall-type combustion boiler

technical field

The invention relates to an arrangement method of a combustion system of a boiler, in particular to an arrangement method of the exhaust air of the new third zone (side wall or rear wall+full furnace) of a wall-type combustion boiler.

Background technique

Almost all coal-fired boilers in power stations in China have adopted low-NOx air staged combustion technology, but the application effect is not satisfactory. Among them, the NOx emissions of high-volatility coal-fired boilers can basically be controlled at around 650mg/m ³ or lower. The NOx emissions of low volatile coal-fired boilers are basically still around 1000mg/m ³ or higher. From a technical point of view, this is related to the existing technical measures of low NOx air staged combustion technology. The existing technical measures have failed to effectively control the excess air ratio at the initial stage of combustion, thereby restricting the denitrification effect of the low NOx air staged combustion technology. On the other hand, deepening the air classification depth on the basis of the existing technology will affect the burnout rate of the pulverized coal flow. How to balance this pair of contradictions has become a major issue that determines the development of low NOx air staging combustion technology, and what technical measures to use to deepen the depth of air staging has become a key technical issue that affects the development of low NOx air staging combustion technology.

The experimental research of air staged combustion technology found that effectively reducing the excess air coefficient in the initial stage of combustion of pulverized coal airflow can effectively restrict the formation of NOx in the early stage of combustion, and the burnout of pulverized coal airflow depends on the supplementary timing of exhaustion air. If the overburning air is replenished in time, the impact on the burnout of the pulverized coal airflow is relatively small; if the overburning air is not replenished in time, it will have a greater impact on the burnout of the pulverized coal airflow. It can be seen that effectively reducing the excess air coefficient at the initial stage of combustion and supplementing the burn-off air in time is a very effective technical approach to greatly reduce NOx emissions while having little effect on the burn-out of pulverized coal airflow. However, the current low-NOx combustion technology and burner arrangement are still unable to achieve this. The supplementary combustion air by the top burn-off air is too late to compensate for the impact of the initial combustion excess air coefficient on the combustion efficiency, resulting in low air classification. The inability of NOx combustion technology to take into account both denitrification effect and combustion efficiency has become a fatal flaw in its development, which seriously limits the development of air staged low NOx combustion technology.

The experimental research of fuel staged combustion technology found that: the proportion of fuel and the flue gas atmosphere when the reburning fuel is injected into the furnace have a greater impact on the reburning effect, the injection position of the reburning fuel has a relatively small impact on the denitrification effect, and the burnout of the pulverized coal flow has a greater impact. relatively large impact. It can be seen that increasing the proportion of reburning fuel and reducing the atmosphere injected into the area is a very effective technical way to greatly reduce NOx emissions, but its impact on combustion efficiency must be reduced. The existing fuel staged combustion technology cannot do this, and it is helpless to use about 15% of the fuel volume as the reburning fuel; at the same time, the reburning zone is separated from the main combustion zone by a certain distance, and it is arranged on the top of the burner to face the coal. The burnout effect of the powder air flow is very large. As a result, the fuel staged low NOx combustion technology cannot take into account the denitrification effect and combustion efficiency at the same time, which has become a fatal flaw in its development and severely limits the development of fuel staged low NOx combustion technology.

Contents of the invention

Aiming at the defects or deficiencies in the above-mentioned prior art, the object of the present invention is to provide a new three-zone secondary (side wall or rear wall + full furnace) exhaust air layout of a wall-type combustion boiler, which can effectively Reduce boiler NOx emissions, while having little effect on the burnout of pulverized coal flow.

In order to achieve the above tasks, the present invention is achieved through the following technical solutions:

A new three-zone secondary burn-off air layout method for a wall-type combustion boiler, which is characterized in that by controlling the excess air coefficient of the pulverized coal flow at the outlet of the burner originally arranged on the front and rear walls or the front wall, the furnace The combustion process is divided into three areas according to the height of the furnace. The lower part is a stable combustion area, the middle part is a deep low-oxygen combustion and reduction area, and the upper part is a two-phase burnout area, and a certain amount of burnout air is arranged on the side wall or rear wall. spout;

In the stable combustion zone at the lower part of the furnace, 1-2 layer burners are selected as the burners in this zone according to the original burner arrangement, and the excess air coefficient of the burners is controlled at 0.9-1.2. The combustion of these burners is based on conventional Stable combustion is the main method;

In the deep low-oxygen combustion and reduction zone in the middle, 1-3 layers of burner nozzles are arranged as the burners in this zone, and the corresponding side wall burnout air outlets (hereinafter referred to as side wall burnout air) are arranged;

In the upper two-phase burnout area, 1-2 layers of top burnout air nozzles (hereinafter referred to as top burnout air) are arranged. The arrangement of these burnout air nozzles in the height direction is compact or remote or compact and Combination of distance type arrangement.

The present invention has the following technical characteristics:

1. The present invention divides the combustion process of the pulverized coal airflow in the furnace into three areas by using the excess air coefficient control of the burner and the setting of the side wall burn-out air and the top burn-off air. In the stable burner, about 25% to 75% % of the fuel is supplied from this zone, which is characterized by conventional combustion and stable combustion. In the combustion and reduction zone, 75% to 25% of the fuel is fed into the furnace from this zone. In this zone, the air staged combustion and fuel staged combustion are the main features, and the initial deep low-oxygen combustion of the pulverized coal flow is combined with the whole area. The NOx reduction reaction is the main feature. In this area, through the control of the excess air coefficient of the burner, the excess air coefficient at the outlet of the burner is in the range of 0.5-0.8, so as to realize the ultra-low oxygen combustion in the initial stage of pulverized coal airflow combustion, and effectively suppress NOx generation. At the same time, the fuel sent into the furnace from this area is equivalent to the reburning fuel in the stable combustion area. Through this super fuel staged combustion method and the deep reducing atmosphere in this area, the NOx generated in the stable combustion area can be reduced, thereby reducing boiler NOx. emissions purposes. In addition, due to the arrangement of the overburning air on the side wall to supplement the combustion-supporting air in the later stage of the pulverized coal flow after ignition, the uneven temperature distribution of the flame along the way has been improved, and the local high temperature at the initial stage of combustion has been reduced, thus realizing the Low-temperature low-oxygen combustion reduces thermal NOx. This arrangement successfully solves the disadvantages of the existing low NOx combustion technology that cannot effectively reduce the excess air coefficient at the initial stage of pulverized coal airflow combustion and cannot increase the proportion of reburning fuel, etc., and successfully solves the problem of poor denitrification effect of the existing low NOx combustion technology question. This arrangement includes conventional combustion, air staged combustion, fuel staged combustion and low-temperature low-oxygen combustion concepts, which are organically combined.

2. This arrangement adopts a two-stage way to supplement the combustion air. First, the side wall burn-off air is injected into the pulverized coal airflow from somewhere in the horizontal direction of the furnace, so as to timely supplement the oxygen in the pulverized coal airflow combustion process, which greatly reduces Influence of ultra-low oxygen combustion mode on the burnout process of pulverized coal flow in the initial stage of small pulverized coal flow. Secondly, in the burnout zone, about 20% of the combustion air is sprayed into the furnace from this zone to replenish the oxygen in the burnout process of the pulverized coal flow, so that the pulverized coal flow can burn completely. This method greatly reduces the excess air coefficient in the early stage of combustion without reducing the excess air coefficient in the main burner area (including the stable combustion zone and the combustion and reduction zone). The amount of oxygen needed for the pulverized coal airflow burnout process is replenished in time, and the ideal denitrification effect is achieved without reducing the combustion efficiency.

3. This arrangement has wide adaptability to coal types, and does not make any changes to the position of the original burner, compared with the original combustion system. Only side or rear wall burnout and top burnout are added. The layout is simple, the system is simple, it is very easy to implement, and the appearance of the boiler itself does not change.

Description of drawings

Fig. 1 is the front view of the furnace side of embodiment 1,5;

Fig. 2 is the front view of the furnace side of embodiment 2,6;

Fig. 3 is the front view of the furnace side of embodiment 3,7;

Fig. 4 is the front view of the furnace side of embodiment 4,8;

Fig. 5 is the A-A direction view of Fig. 1-4;

Fig. 6 is the A-A direction view of Fig. 1-4, 7-10, 11-14, 15-16, 17-20;

Fig. 7 is the front view of the furnace side of embodiment 9;

Fig. 8 is the front view of the furnace side of embodiment 10;

Fig. 9 is the front view of the furnace side of embodiment 11;

Fig. 10 is the front view of the furnace side of embodiment 12;

Fig. 11 is the front view of the furnace side of embodiment 13;

Fig. 12 is the front view of the furnace side of embodiment 14;

Fig. 13 is the front view of the furnace side of embodiment 15;

Fig. 14 is the front view of the furnace side of embodiment 16;

Fig. 15 is the front view of the furnace side of embodiment 17;

Fig. 16 is the front view of the furnace side of embodiment 18;

Fig. 17 is the front view of the furnace side of embodiment 19;

Fig. 18 is the front view of the furnace side of embodiment 20;

Fig. 19 is the front view of the furnace side of embodiment 21;

Fig. 20 is the front view of the furnace side of embodiment 22;

Fig. 21 is the front view of the furnace side of embodiment 23;

Fig. 22 is the front view of the furnace side of embodiment 24;

Fig. 23 is the front view of the furnace side of embodiment 25;

Fig. 24 is the front view of the furnace side of embodiment 26;

Fig. 25 is the A-A direction view of Fig. 21-24;

In the figure, 1- is the burner of the wall-type combustion boiler, 2- is the side wall or rear wall burn-out air nozzle, 3- is the top burn-off air nozzle, 4- is the exhaust gas or tertiary air of the wall-type combustion boiler spout

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Detailed ways

In the new three-zone secondary burn-off air arrangement of the wall-type combustion boiler of the present invention, the combustion process in the furnace is divided into three zones through the control of the excess air coefficient of the pulverized coal flow at the outlet of the burner in different layers in the direction of the height of the burner furnace. The lower part is the stable combustion zone (hereinafter referred to as the stable combustion zone), the middle part is the deep low-oxygen combustion and reduction zone (hereinafter referred to as the combustion and reduction zone), and the upper part is the two-phase burnout zone (hereinafter referred to as the burnout zone).

In the lower stable combustion zone, the 1-2 layer burners are selected as the burners in the stable combustion zone according to the burner arrangement of the wall-fired boiler, and the excess air coefficient is controlled according to the characteristics of coal combustion to ensure stable combustion. The value is around 1.0;

In the combustion and reduction area in the middle, arrange 1-3 layers of burners, and arrange 1-3 layers of side walls or rear walls to burn out the wind. The excess air coefficient at the outlet of the burner in this zone is controlled within the range of 0.5-0.8 according to the type of coal. The purpose is to form deep low-oxygen combustion in the early stage of combustion, suppress the formation of NOx, and reduce the NOx generated by the stable burner at the same time. The burn-out air nozzles on the side wall are arranged on the two side walls of the wall-type combustion boiler to supplement the combustion-supporting air in the later stage of the pulverized coal airflow after ignition. The installation elevation corresponds to the elevation of the burner nozzle in the middle combustion and reduction zone.

In the upper two-phase burnout area, 1-2 layers of top burnout air nozzles are arranged, and the burnout air nozzles can be arranged in a compact or remote type or a combination of compact and remote types in the height direction.

The following are examples given by the inventors.

Example 1:

Referring to Fig. 1 and Fig. 5, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 4 layers, and each wall has 3 burner nozzles on each layer. The lowest layer of burners is a stable combustion zone. The outlet excess air coefficient of the 6 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzles on the upper 3 floors are deep low-oxygen combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 3 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 3-layer burner nozzles, so as to ensure that the center of the overfire air and the combustion airflow center of the upper 3-layer burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange two layers of top burn-off air nozzles above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact or remote or a combination of compact and remote. Way.

Example 2:

Referring to Fig. 2 and Fig. 5, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 4 layers, and each wall has 3 burner nozzles on each layer. The lowest layer of burners is a stable combustion zone. The outlet excess air coefficient of the 6 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzles on the upper 3 floors are deep low-oxygen combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 3 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 3-layer burner nozzles, so as to ensure that the center of the overfire air and the combustion airflow center of the upper 3-layer burners are on the same elevation. Two side wall overburning air nozzles are symmetrically arranged on each side wall and each layer, so that after the airflow from the two overburning air nozzles is mixed in the center of the furnace, its synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the coal of the two burners in the middle. Combustion air for powder airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 3:

Referring to Fig. 3 and Fig. 5, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler against each other in 4 layers, and each wall has 3 burner nozzles on each layer. The bottom 2 burners are the stable combustion zone. The excess air coefficient at the outlet of the 12 burners in the 2 floors is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of the pulverized coal flow. The burner nozzles on the upper 2 floors are deep hypoxic combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 2 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 2 layers of burner nozzles, so as to ensure that the center energy of the overfire air and the combustion air flow center of the upper 2 layers of burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 4:

Referring to Fig. 4 and Fig. 5, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler against each other in 4 layers, and each wall has 3 burner nozzles on each layer. The bottom 2 burners are the stable combustion zone. The excess air coefficient at the outlet of the 12 burners in the 2 floors is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of the pulverized coal flow. The burner nozzles on the upper 2 floors are deep hypoxic combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 2 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 2 layers of burner nozzles, so as to ensure that the center energy of the overfire air and the combustion air flow center of the upper 2 layers of burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 5:

Referring to Fig. 1 and Fig. 6, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 4 layers, and each wall has 4 burner nozzles on each layer. The lowest layer of burners is a stable combustion zone. The excess air coefficient of the 8 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal flow. The burner nozzles on the upper 3 floors are deep low-oxygen combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 3 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 3-layer burner nozzles, so as to ensure that the center of the overfire air and the combustion airflow center of the upper 3-layer burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 5:

Referring to Fig. 2 and Fig. 6, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 4 layers, and each wall has 4 burner nozzles on each layer. The lowest layer of burners is a stable combustion zone. The excess air coefficient of the 8 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal flow. The burner nozzles on the upper 3 floors are deep low-oxygen combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 3 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 3-layer burner nozzles, so as to ensure that the center of the overfire air and the combustion airflow center of the upper 3-layer burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Embodiment 7:

Referring to Fig. 3 and Fig. 6, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 4 layers, and each wall has 4 burner nozzles on each layer. The bottom two layers of burners are stable combustion zones. The outlet excess air coefficient of the 16 burners in the two layers is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzles on the upper 2 floors are deep hypoxic combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 2 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 2 layers of burner nozzles, so as to ensure that the center energy of the overfire air and the combustion air flow center of the upper 2 layers of burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Embodiment 8:

Referring to Fig. 4 and Fig. 6, there are 4 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 4 layers, and each wall has 4 burner nozzles on each layer. The bottom two layers of burners are stable combustion zones. The outlet excess air coefficient of the 16 burners in the two layers is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzles on the upper 2 floors are deep hypoxic combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 2 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 2 layers of burner nozzles, so as to ensure that the center energy of the overfire air and the combustion air flow center of the upper 2 layers of burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or remote.

Embodiment 9:

Referring to Fig. 7 and Fig. 6, there are 3 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 3 layers, and each wall has 4 burner nozzles on each layer. The lowest layer of burners is a stable combustion zone. The excess air coefficient of the 8 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal flow. The burner nozzles on the upper 2 floors are deep hypoxic combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 2 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 2 layers of burner nozzles, so as to ensure that the center energy of the overfire air and the combustion air flow center of the upper 2 layers of burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 10:

Referring to Fig. 8 and Fig. 6, there are 3 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler against each other in 3 layers, and each wall has 4 burner nozzles on each layer. The lowest layer of burners is a stable combustion zone. The excess air coefficient of the 8 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal flow. The burner nozzles on the upper 2 floors are deep hypoxic combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 2 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 2 layers of burner nozzles, so as to ensure that the center energy of the overfire air and the combustion air flow center of the upper 2 layers of burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or remote.

Example 11:

Referring to Fig. 9 and Fig. 6, there are 3 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 3 layers, and each wall has 4 burner nozzles on each layer. The bottom two layers of burners are stable combustion zones. The outlet excess air coefficient of the 16 burners in the two layers is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzle on the upper layer is a deep low-oxygen combustion and reduction zone, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8, and a layer of side wall burnout air nozzles is arranged on the 2 side walls of this area. The elevation is slightly higher than the nozzle of the upper burner, so as to ensure that the center of the overfire air and the center of the combustion air flow of the upper burner are on the same elevation. Two side wall overburning air nozzles are symmetrically arranged on each side wall and each layer, so that after the airflow from the two overburning air nozzles is mixed in the center of the furnace, its synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the coal of the two burners in the middle. Combustion air for powder airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 12:

Referring to Fig. 10 and Fig. 6, there are 3 layers of burner nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in 3 layers, and each wall has 4 burner nozzles on each layer. The bottom two layers of burners are stable combustion zones. The outlet excess air coefficient of the 16 burners in the two layers is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzle on the upper layer is a deep low-oxygen combustion and reduction zone, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8, and a layer of side wall burnout air nozzles is arranged on the 2 side walls of this area. The elevation is slightly higher than the nozzle of the upper burner, so as to ensure that the center of the overfire air and the center of the combustion air flow of the upper burner are on the same elevation. Two side wall overburning air nozzles are symmetrically arranged on each side wall and each layer, so that after the airflow from the two overburning air nozzles is mixed in the center of the furnace, its synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the coal of the two burners in the middle. Combustion air for powder airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 13:

Referring to Fig. 11 and Fig. 6, there are three layers of burner nozzles on the front and rear walls of this embodiment, the elevation of the burners on the three layers of the rear wall is lower than that of the corresponding three layers on the front wall, and there are four burner nozzles on each layer of each wall . The burners at the bottom of the front and rear walls are the stable combustion zone. The excess air coefficient of the 8 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of the pulverized coal flow. The two layers of burner nozzles on the front and rear walls are deep low-oxygen combustion and reduction zones, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8. Two layers of side wall burnout air nozzles are arranged on the two side walls of this area. The elevation of the 2-layer nozzle is slightly higher than that of the upper 2-layer burner nozzle, so as to ensure that the center energy of the overfired air is on the same elevation as the combustion air flow center of the upper 2-layer burner. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 14:

Referring to Fig. 12 and Fig. 6, there are three layers of burner nozzles on the front and rear walls of this embodiment, the elevation of the burners on the three layers of the rear wall is lower than that of the corresponding three layers on the front wall, and there are four burner nozzles on each layer of each wall . The burners at the bottom of the front and rear walls are the stable combustion zone. The excess air coefficient of the 8 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of the pulverized coal flow. The burner nozzles on the upper 2 floors are deep hypoxic combustion and reduction zones, and the excess air coefficient at the outlet of the burners is controlled within the range of 0.5 to 0.8, and 2 layers of side wall burnout air nozzles are arranged on the 2 side walls of this area. The elevation of the layer nozzle is slightly higher than that of the upper 2 layers of burner nozzles, so as to ensure that the center energy of the overfire air and the combustion air flow center of the upper 2 layers of burners are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 15:

Referring to Fig. 13 and Fig. 6, there are 3 layers of burner nozzles on the front and rear walls of this embodiment, the elevation of the 3 layers of burners on the rear wall is lower than that of the corresponding 3 layers of burners on the front wall, and there are 4 burner nozzles on each layer of each wall . The burners on the lower two floors of the front and rear walls are stable combustion zones. The excess air coefficient at the exit of the 16 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzle on the upper layer of the front and rear walls is a deep low-oxygen combustion and reduction zone, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8, and a layer of side wall burnout air nozzle is arranged on the 2 side walls of this area. The elevation of the nozzle is slightly higher than the nozzle of the upper burner, so as to ensure that the center of the overfire air and the center of the combustion air flow of the upper burner are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 16:

Referring to Fig. 14 and Fig. 6, there are three layers of burner nozzles on the front and rear walls of this embodiment, the elevation of the burners on the three layers of the rear wall is lower than that of the corresponding three layers on the front wall, and there are four burner nozzles on each layer of each wall . The burners on the lower two floors of the front and rear walls are stable combustion zones. The excess air coefficient at the exit of the 16 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The burner nozzle on the upper layer is a deep low-oxygen combustion and reduction zone, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8, and a layer of side wall burnout air nozzles is arranged on the 2 side walls of this area. The elevation is slightly higher than the nozzle of the upper burner, so as to ensure that the center of the overfire air and the center of the combustion air flow of the upper burner are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 17:

Referring to Fig. 15 and Fig. 6, there are 2 layers of burner nozzles and 1 layer of exhaust air nozzles in this embodiment, which are arranged in 3 layers on the front and rear walls of the wall-type combustion boiler, and each wall has 4 burner nozzles per layer. The lowest layer of burners is a stable combustion zone. The excess air coefficient of the 8 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal flow. The burner nozzle on the upper layer is a deep low-oxygen combustion and reduction zone, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8, and the burn-out air nozzle on the side wall of the first layer is arranged on the second side wall of this area. The elevation of the nozzle is slightly higher than the nozzle of the upper burner, so as to ensure that the center of the overfire air and the center of the combustion air flow of the upper burner are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 18:

Referring to Fig. 16 and Fig. 6, there are 2 layers of burner nozzles and 1 layer of exhaust air nozzles in this embodiment, which are arranged on the front and rear walls of the wall-type combustion boiler in three layers, and each wall has 4 burner nozzles per layer. The lowest layer of burners is a stable combustion zone. The excess air coefficient of the 8 burners in this layer is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal flow. The burner nozzle on the upper layer is a deep low-oxygen combustion and reduction zone, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8, and a layer of side wall burnout air nozzles is arranged on the 2 side walls of this area. The elevation is slightly higher than the nozzle of the upper burner, so as to ensure that the center of the overfire air and the center of the combustion air flow of the upper burner are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 19:

Referring to Fig. 17 and Fig. 6, there are 3 layers of burner spouts on the front wall of the present embodiment, and the rear wall is 2 layers of burner spouts, and each wall has 4 burner spouts on every layer. The burners at the bottom of the front and rear walls are the stable combustion zone. The excess air coefficient of the 8 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of the pulverized coal flow. The burner nozzles on the 2nd layer on the front wall and the upper layer on the rear wall are deep low-oxygen combustion and reduction zones, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8. The air exhaust nozzle, the elevation of the 2-layer nozzle is slightly higher than that of the upper 2-layer burner nozzle, so as to ensure that the center of the exhaust air and the combustion airflow center of the upper 2-layer burner are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 20:

Referring to Fig. 18 and Fig. 6, there are 3 layers of burner spouts on the front wall of the present embodiment, and the rear wall is 2 layers of burner spouts, and each wall has 4 burner spouts on every layer. The burners at the bottom of the front and rear walls are the stable combustion zone. The excess air coefficient of the 8 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of the pulverized coal flow. The burner nozzles on the second floor on the front wall and the upper floor on the rear wall are deep low-oxygen combustion and reduction zones. The excess air coefficient at the burner outlet in this zone is controlled within the range of 0.5 to 0.8. The burnout air nozzle on the wall, the elevation of the nozzle on the 2nd floor is slightly higher than that of the burner nozzle on the upper 2nd floor, so as to ensure that the center of the burnout air is at the same elevation as the combustion airflow center of the burner on the upper 2nd floor. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 21:

Referring to Fig. 19 and Fig. 6, there are 3 layers of burner spouts on the front wall of the present embodiment, and the back wall is 2 layers of burner spouts, and each wall has 4 burner spouts on every layer. The burners on the lower 2 floors of the front wall and the lowest floor of the rear wall are stable combustion zones. The excess air coefficient at the outlet of the 12 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly based on the stable combustion of pulverized coal airflow feature. The burner nozzles on the 2nd layer on the front wall and the upper layer on the rear wall are deep low-oxygen combustion and reduction zones, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8. The air exhaust nozzle, the elevation of the nozzle of this layer is slightly higher than that of the burner nozzle of the upper layer, so as to ensure that the center of the exhaust air is at the same elevation as the center of the combustion airflow of the upper 2 burners. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Two layers of top burn-off air nozzles are arranged above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact, remote or a combination of compact and remote. Way.

Example 22:

Referring to Fig. 20 and Fig. 6, there are 3 layers of burner spouts on the front wall of the present embodiment, and the rear wall is 2 layers of burner spouts, and each wall has 4 burner spouts on every layer. The burners on the lower 2 floors of the front wall and the lowest floor of the rear wall are stable combustion zones. The excess air coefficient at the outlet of the 12 burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly based on the stable combustion of pulverized coal airflow feature. The burner nozzles on the upper layer of the front wall and the upper layer of the rear wall are deep low-oxygen combustion and reduction areas. The excess air coefficient of the burner outlet in this area is controlled within the range of 0.5 to 0.8, and a layer of side wall combustion is arranged on the 2 side walls of this area. The air exhaust nozzle, the elevation of the nozzle of this layer is slightly higher than the nozzle of the upper burner, so as to ensure that the center of the exhaust air and the center of the combustion air flow of the upper burner are on the same elevation. Each side wall and each layer are symmetrically arranged with 2 side wall overburning air nozzles, so that after the two overburning air flows are mixed in the center of the furnace, their synthesis speed points to the center of the furnace and flows to the center of the furnace to supplement the pulverized coal of the two burners in the middle Combustion air for airflow burnout process. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or distant.

Example 23:

Referring to Fig. 21 and Fig. 25, the present embodiment only has 4 layers of burner spouts on the front wall, no burner spouts on the back wall, and 4 burner spouts on every layer of the front wall. The burners at the bottom of the front wall are stable combustion zones. The excess air coefficient of the four burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The 3-layer burner nozzle on the front wall is a deep low-oxygen combustion and reduction zone, the excess air coefficient of the burner outlet is controlled within the range of 0.5 to 0.8, and the 2-layer rear wall burnout air nozzle is arranged on the rear wall of this area. The elevation of the nozzle on the second layer is slightly higher than that of the burner nozzle on the second layer and the third layer, so as to ensure that the center energy of the overfire air and the center of the combustion air flow of the corresponding layer burner are on the same elevation. Each floor of the rear wall is correspondingly arranged with 4 rear wall burnout air nozzles, and the nozzles are in the form of swirl nozzles. To supplement the combustion air in this area. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange two layers of top burn-off air nozzles above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact or remote or a combination of compact and remote. Way.

Example 24:

Referring to Fig. 22 and Fig. 25, the present embodiment only has 4 layers of burner spouts on the front wall, no burner spouts on the back wall, and 4 burner spouts on every layer of the front wall. The burners at the bottom of the front wall are stable combustion zones. The excess air coefficient of the four burners in this zone is controlled within the range of 0.9-1.2. The combustion in this zone is mainly characterized by the stable combustion of pulverized coal airflow. The 3-layer burner nozzle on the front wall is a deep low-oxygen combustion and reduction zone, the excess air coefficient of the burner outlet is controlled within the range of 0.5 to 0.8, and the 2-layer rear wall burnout air nozzle is arranged on the rear wall of this area. The elevation of the nozzle on the second layer is slightly higher than that of the burner nozzle on the second layer and the third layer, so as to ensure that the center energy of the overfire air and the center of the combustion air flow of the corresponding layer burner are on the same elevation. Each floor of the rear wall is correspondingly arranged with 4 rear wall burnout air nozzles, and the nozzles are in the form of swirl nozzles. To supplement the combustion air in this area. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or remote.

Example 25:

Referring to Fig. 23 and Fig. 25, the present embodiment only has 4 layers of burner spouts on the front wall, no burner spouts on the back wall, and 4 burner spouts on every layer of the front wall. The burners on the bottom 2 floors of the front wall are stable combustion areas. The excess air coefficient of the 8 burners in this area is controlled within the range of 0.9-1.2. The combustion in this area is mainly characterized by the stable combustion of pulverized coal airflow. The two-layer burner nozzles on the front wall are deep low-oxygen combustion and reduction areas, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8. The two-layer rear wall burnout air nozzles are arranged on the rear wall of this area. The elevation of the nozzles on the second floor is slightly higher than that of the burners on the upper two floors, so as to ensure that the center energy of the overfire air and the combustion airflow center of the corresponding layer burners are on the same elevation. Each layer of the back wall corresponds to the front wall burner and arranges 4 rear wall burnout air nozzles, and the nozzles are in the form of swirl nozzles. To supplement the combustion air in this area. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange two layers of top burn-off air nozzles above the burner, and their horizontal positions correspond to the arrangement of the burners one by one. The arrangement in the height direction can be compact or remote or a combination of compact and remote. Way.

Example 26:

Referring to 24 and Fig. 25, only the front wall has 4 layers of burner spouts in the present embodiment, the back wall has no burner spouts, and each layer of the front wall has 4 burner spouts. The burners on the bottom 2 floors of the front wall are stable combustion areas. The excess air coefficient of the 8 burners in this area is controlled within the range of 0.9-1.2. The combustion in this area is mainly characterized by the stable combustion of pulverized coal airflow. The two-layer burner nozzles on the front wall are deep low-oxygen combustion and reduction areas, and the excess air coefficient at the burner outlet is controlled within the range of 0.5 to 0.8. The two-layer rear wall burnout air nozzles are arranged on the rear wall of this area. The elevation of the nozzles on the second floor is slightly higher than that of the burners on the upper two floors, so as to ensure that the center energy of the overfire air and the combustion airflow center of the corresponding layer burners are on the same elevation. Each layer of the back wall corresponds to the front wall burner and arranges 4 rear wall burnout air nozzles, and the nozzles are in the form of swirl nozzles. To supplement the combustion air in this area. The total excess air coefficient in this area is controlled within the range of 0.8-1.0 according to the characteristics of the coal type.

Arrange a layer of top burn-off air nozzles above the burners, and their horizontal positions correspond to the arrangement of the burners one by one, and the arrangement in the height direction can be compact or remote.

The working principle of the present invention is as follows:

The layout of the new three zones of the wall-type combustion boiler with the same secondary burn-off air is based on the principles of conventional combustion, air staged combustion, fuel staged combustion, and low-temperature low-oxygen combustion, successfully solving the problem that the existing low-NOx combustion technology cannot effectively reduce the pulverized coal flow. The disadvantages of excess air ratio in the initial stage of combustion and increasing the proportion of reburning fuel can greatly reduce the excess air ratio in the initial combustion of pulverized coal flow in the combustion and reduction zone without reducing the excess air ratio in the main combustion area. About 75% of boiler NOx emissions are generated in the early stage of combustion, and the generated amount is directly proportional to the excess air coefficient. It can be seen that controlling the excess air coefficient of the pulverized coal flow at the outlet of the burner in the combustion and reduction zone can greatly inhibit the pulverized coal flow in this area. NOx formation from combustion processes. At the same time, the disadvantage that the existing low NOx combustion technology cannot increase the share of reburned fuel is successfully solved. The amount of 30-75% fuel sprayed into the furnace from the combustion and reduction zone is equivalent to the reburning fuel of the combustion product in the stable combustion zone. The large amount of reburning fuel and the reducing atmosphere in this zone can reduce the NOx generated in the stable combustion zone Exhausted. In addition, the side wall burnout air makes the temperature distribution of the furnace flame tend to be uniform, and the local high temperature decreases, which has a certain low-temperature combustion effect. To sum up, the layout of the new three-zone wall-type combustion boiler with the second-level burn-off air rationally and comprehensively applies the concepts of air staged combustion, fuel staged combustion and low-temperature low-oxygen combustion, which can make the denitrification of coal-fired boilers The effect is very obvious, surpassing the existing low NOx combustion technology, that is to say, the comprehensive effect of the above three can greatly reduce the NOx emission of coal-fired boilers at the current level.

The two-stage overburning air compensation method and the setting of the overburning air on the side wall or the rear wall conform to the conventional combustion concept. 1) The air in the pulverized coal airflow combustion process is replenished in time, which greatly reduces the impact of the initial deep low oxygen combustion mode on the pulverized coal airflow burnout process. 2) The pulverized coal flow in the stable combustion zone is arranged according to the conventional combustion method, and its burnout process is basically not affected. Favorable for the burnout process. Because of this, this arrangement has less impact on combustion efficiency than air staged combustion techniques.

Compared with the existing air staged combustion technology, this arrangement only adds side wall burn-out air on the two side walls of the wall-type combustion boiler; compared with the fuel staged combustion technology, there is no need to add a reburning system, and the construction is very simple. Moreover, the appearance of the boiler body does not need to be changed, and there is almost no additional investment for new boilers. When it is used for the transformation of boilers that have already been put into operation, there is no need to add any equipment to the original combustion system, and the air and powder supply system does not need to be modified. It is very easy to implement. .

The layout of the new three-zone secondary burn-off air of the wall-type combustion boiler of the present invention is suitable for wall-type combustion boilers of various capacities.

Claims (6)

1. A new three-zone secondary burn-off air layout method for wall-type combustion boilers, characterized in that, by controlling the excess air coefficient of the pulverized coal flow at the outlet of the burner originally arranged on the front and rear walls or the front wall, the The combustion process in the furnace is divided into three areas according to the height of the furnace, the lowest part is the stable combustion area, the middle part is the deep low-oxygen combustion and reduction area, and the upper part is the two-phase burnout area, and the burnout air is arranged on the side wall or the rear wall. spout; In the stable combustion zone at the lower part of the furnace, 1-2 layer burners are selected as the burners in this zone according to the layout of the original burners, and the combustion of these burners is mainly based on the conventional stable combustion method; In the deep low-oxygen combustion and reduction zone in the middle, arrange 1-3 layers of burner nozzles as the burners in this zone, and arrange the corresponding side wall burnout tuyere; In the upper two-phase burnout area, 1-2 layers of top burn-off air nozzles are arranged. The horizontal positions of these top burn-off air nozzles correspond to the arrangement of the burners one by one, and the height direction and the arrangement position of the burners are compact. type or remote type or a combination of compact type and remote type. 2. The arrangement according to claim 1, characterized in that the excess air ratio in the stable combustion zone is controlled at 0.9-1.2. 3. The arrangement according to claim 1, characterized in that, the excess air ratio of the burner outlet of the deep hypoxic combustion and reduction zone is controlled between 0.5-0.8; at the same time, the arrangement and The corresponding overburning air nozzle; the number of layers, quantity and installation elevation of the overburning air nozzle is the same as or less than the number of burner nozzle layers in the deep low-oxygen combustion and reduction zone in the middle, and the number is the same or less than one layer. , corresponding to the elevation. 4. The arrangement according to claim 1, characterized in that, the arrangement of the burn-out air nozzles on the side walls of the deep hypoxic combustion and reduction zone is as follows: 2 burn-out air nozzles are arranged on each side wall of each floor, The two overburning air nozzles are sprayed into the furnace at an oblique angle in the horizontal direction. The overburning air nozzles are in the form of straight-flow nozzles or swirl nozzles, and the number of layers is the same as or less than the number of burner layers in this area. 5. The arrangement according to claim 1, characterized in that the top burn-off air nozzles of the two-phase burn-out zone are 1-2 layers, arranged on the front and rear walls, and the way is compact or remote or The combination of compact type and remote type is arranged. The overfire air nozzle is in the form of a straight nozzle or a swirl nozzle, which can shield the updraft in the entire furnace and mix well with it. 6. The arrangement according to claim 4, characterized in that, when the original burners in the deep hypoxic combustion and reduction zone are arranged on the front wall, the arrangement of the burn-out air nozzles on the back wall is 4 per floor Burn-out air nozzles, these burn-out air nozzles are swirl nozzles, and the number of layers is the same as or less than the number of burner layers in the combustion and reduction area of the front wall.

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