Efficient direct-current burner and turbulent burner collaborative combustion device and collaborative combustion method

Abstract

The invention relates to the technical field of tangential boiler combustion, in particular to a cooperative combustion device and method for an efficient direct-flow combustor and a turbulent-flow combustor, and aims to solve the problem that a corner tangential boiler cannot stably operate under the lower rated load of 15%. Based on the collaborative combustion method of the direct-current combustor and the cyclone combustor, the direct-current primary air speed is increased by introducing an air supplementing system for increasing the air speed and the air temperature of the direct-current combustor and increasing the air temperature of the cyclone combustor, and the direct-current primary air speed is increased by introducing an air supplementing system for increasing the air temperature of the direct-current combustor and the air temperature of the cyclone combustor; therefore, the direct-current primary air injection capacity is improved, the shape and size of a central backflow area are adjusted, and the problem that a nozzle of a direct-current combustor is burnt out due to overheating caused by too low air speed of an air pipe is solved. Meanwhile, the temperature of direct-current primary air and the temperature of primary air of the self-service stable-combustion combustor are increased, the temperature of primary air powder at an inlet of the boiler can be increased, initial ignition and burnout of pulverized coal are enhanced, and the device is mainly used for improving the stable-combustion effect of the boiler under the working condition that the rated power is lower than 15%.

Description

Technical Field

[0001] The invention relates to the technical field of tangential boiler combustion, and in particular to a high-efficiency direct current burner and swirl burner coordinated combustion device and a coordinated combustion method. Background Art

[0002] The proportion of fossil energy in the energy structure is decreasing year by year, while the proportion of new energy power generation in the energy structure is increasing, which is undoubtedly a positive measure to promote environmental protection and sustainable development. However, there are also some shortcomings in new energy power generation, among which the most notable is the intermittent nature of its power generation and the instability affected by the environment. These shortcomings make new energy power generation limited in meeting the power supply demand during the peak load of the power grid. Therefore, it is necessary to carry out flexibility transformation of thermal power units so that they can absorb more clean energy. When the power generation of new energy is unstable, the output of thermal power units is fully utilized, and the power generation is reduced during the low power consumption period or when the new energy is stable, so as to achieve deep peak regulation. In the flexibility transformation to improve the peak regulation capacity of the unit, the most critical issue is to achieve stable operation of the boiler at a low load of 20%-30% or even lower.

[0003] Coal-fired boiler power generation is the main body of my country's current energy structure. The combustion method of coal-fired boilers mainly adopts the arrangement of direct current burners on the four corners or eight corners of the boiler furnace. The coal powder airflow and the secondary air are sprayed into the furnace through the direct current burner jets and merged in the form of a tangent circle. The coal powder airflow is directly hit by the high-temperature flame of the upstream adjacent corner on the side facing the fire and ignited. The four-corner (or eight-corner) tangent pulverized coal combustion boiler is the most widely used and mature furnace type in my country's power plants, accounting for more than 70% of the total installed capacity. At present, the stable combustion load of the four-corner (or eight-corner) tangent pulverized coal boiler of domestic coal-fired power units can reach 30%-40% without oil injection, but it is difficult to achieve a stable combustion effect of 20%-30% of the rated load by relying solely on coal powder combustion, resulting in the four-corner (or eight-corner) tangent pulverized coal boiler being unable to meet the requirements of deep peak regulation.

[0004] At present, four-corner (or octagonal) cut-circle boilers need to use micro-oil or plasma technology to achieve stable combustion when the rated load is 20%-30%. Micro-oil stable combustion technology uses a small amount of oil (oil gun output 0.4t / h-0.6t / h) to ignite coal powder, and strengthens the ignition and stable combustion of coal powder through its own combustion heat release. It has the advantage of strong adaptability to coal types and is applicable to both lignite boilers and anthracite boilers. The disadvantage is that long-term operation has a certain negative impact on the electrostatic precipitator electrode and desulfurization slurry. On the other hand, the annual oil consumption of using oil guns for stable combustion can reach more than 10,000 tons, which is poor in economic efficiency and extremely costly. Plasma stable combustion technology mainly uses a high-power plasma gun to generate a high-temperature arc to strengthen the ignition and stable combustion of coal powder. It has the characteristics of economy and environmental protection, but it has the disadvantages of short cathode working life and poor coal quality adaptability. It is often used in bituminous coal boilers with high volatile matter.

[0005] In the prior art, a DC burner and a swirl burner cooperative combustion device has been developed, in which a self-help stabilizing combustion burner is arranged between the DC primary air and the DC secondary air, and the original DC burner and the self-help stabilizing combustion burner are used for cooperative combustion, so that the four-corner (or eight-corner) cut-circle boiler can operate stably only by coal powder combustion at 20%-30% of the rated load, and the burnout effect is improved at high load. However, actual application shows that after applying the device, it is found that the four-corner cut-circle boiler cannot operate stably at a rated load lower than 15%, and the DC burner may have problems such as nozzle overheating and burning due to too low primary air speed, and pipeline powder blockage. Therefore, in order to solve the above problems, the present invention proposes a high-efficiency DC burner and swirl burner cooperative combustion device and a cooperative combustion method. Summary of the invention

[0006] The present invention aims to solve the problem that the four-corner tangential boiler cannot stably operate at a rated load lower than 15%, and the DC burner may overheat and burn the nozzle due to too low a primary wind speed, and the pipeline may be blocked by powder, and thus provide a high-efficiency DC burner and swirl burner coordinated combustion device and coordinated combustion method;

[0007] A high-efficiency direct current burner and swirl burner cooperative combustion device, the cooperative combustion device comprises a four-corner tangential pulverized coal combustion boiler, a secondary wind box and four direct current pulverized coal burners, the four direct current pulverized coal burners are respectively arranged at the four corners of the four-corner tangential pulverized coal combustion boiler, each direct current pulverized coal burner corresponds to at least one coal mill, the direct current primary air nozzle in the direct current pulverized coal burner is connected to the coal outlet end of the coal mill through a coal supply pipeline, the direct current secondary air nozzle in the direct current pulverized coal burner is connected to the air outlet end of the secondary wind box through an air supply pipeline, each direct current pulverized coal burner is arranged with at least one self-help stabilizing combustion burner, and each self-help stabilizing combustion burner is arranged at Corresponding to the DC primary air nozzle and the DC secondary air nozzle located on the same layer in the DC pulverized coal burner, the self-service stable combustion burner is connected to the coal supply pipeline of the adjacent DC primary air nozzle and the air supply pipeline of the adjacent DC secondary air nozzle through the air-powder system, and the coordinated combustion device also includes an air supply system and a wind temperature and air supply system, the No. 1 air outlet end of the air supply system is connected to the air inlet end of each coal mill, the No. 2 air outlet end of the air supply system is connected to the air inlet end of the secondary air box, the air inlet end of the wind temperature and air supply system is connected to the air supply system, the DC air supply end of the wind temperature and air supply system is connected to the coal supply pipeline, and the swirl air supply end of the wind temperature and air supply system is connected to the air powder system;

[0008] Furthermore, each coal mill is equipped with a corresponding coal feeder, and the coal outlet of each coal feeder is connected to the coal inlet of the corresponding coal mill through a coal drop pipe;

[0009] Further, the coal supply pipeline includes a DC primary air channel, a primary air duct and a No. 1 regulating valve, one end of the DC primary air channel is connected to the corresponding DC primary air nozzle, one end of the primary air duct is connected to the coal outlet end of the corresponding coal mill, the other end of the DC primary air channel is connected to the other end of the primary air duct, and the No. 1 regulating valve is installed at the connection between the DC primary air channel and the primary air duct;

[0010] The coal supply pipeline also includes a No. 2 regulating valve, a No. 3 regulating valve, a No. 1 pulverized coal pipeline and a pulverized coal separation device. The coal inlet end of the pulverized coal separation device is connected to the primary air duct, and the No. 2 regulating valve is connected in series to the primary air duct. The No. 1 coal outlet end of the pulverized coal separation device is connected to the DC primary air channel through the No. 1 pulverized coal pipeline, and the No. 3 regulating valve is connected in series to the No. 1 pulverized coal pipeline.

[0011] Further, the air supply pipeline includes a DC secondary air channel, a secondary air duct and a No. 4 regulating valve, one end of the DC secondary air channel is connected to the corresponding DC secondary air nozzle, one end of the secondary air duct is connected to the air outlet end of the corresponding secondary air box, the other end of the DC secondary air channel is connected to the other end of the secondary air duct, and a No. 4 regulating valve is installed at the connection between the DC secondary air channel and the secondary air duct:

[0012] Furthermore, the self-help combustion stabilizing burner comprises a combustion stabilizing chamber, a secondary air channel in a swirl and a DC primary air channel of the self-help combustion stabilizing burner, the secondary air channel in the swirl is coaxially sleeved on the outside of the DC primary air channel of the self-help combustion stabilizing burner, and one end of the DC primary air channel of the self-help combustion stabilizing burner and one end of the secondary air channel in the swirl are both connected to the combustion stabilizing chamber, the other end of the DC primary air channel of the self-help combustion stabilizing burner is connected to a coal supply pipeline through an air-powder system, and the other end of the secondary air channel in the swirl is connected to an air supply pipeline through an air-powder system, and an axial blade group is provided between the DC primary air channel of the self-help combustion stabilizing burner and the secondary air channel in the swirl, and the axial blade group is arranged close to the combustion stabilizing chamber, the axial blade group comprises a plurality of axial blades, and the plurality of axial blades are equidistantly arranged along the circumferential direction between the DC primary air channel of the self-help combustion stabilizing burner and the secondary air channel in the swirl, and one end of each axial blade is connected to an outer wall of the DC primary air channel of the self-help combustion stabilizing burner, and the other end of each axial blade is connected to an inner wall of the secondary air channel in the swirl;

[0013] Furthermore, the air-powder system includes a DC coal supply pipeline and a swirl air supply pipeline, the coal supply pipeline is connected with the DC primary air channel of the self-help stable combustion burner through the DC coal supply pipeline, and the air supply pipeline is connected with the secondary air channel in the swirl through the swirl air supply pipeline;

[0014] The DC coal supply pipeline includes a DC connecting air duct of the self-service stable combustion burner, a No. 5 regulating valve, a No. 2 pulverized coal channel and a No. 6 regulating valve. The primary air duct is connected with the DC primary air channel of the self-service stable combustion burner through the DC connecting air duct of the self-service stable combustion burner, and the No. 5 regulating valve is connected in series to the DC connecting air duct of the self-service stable combustion burner. The No. 2 coal outlet end of the pulverized coal separation device is connected with the DC primary air channel of the self-service stable combustion burner through the No. 2 pulverized coal channel, and the No. 6 regulating valve is connected in series to the No. 2 pulverized coal channel.

[0015] The swirl air supply pipeline includes a swirl connecting air duct of the self-service stabilizing combustion burner and a No. 7 regulating valve. The secondary air duct is connected with the secondary air channel in the swirl through the swirl connecting air duct of the self-service stabilizing combustion burner. The connecting point of the secondary air channel in the swirl and the self-service stabilizing combustion burner connecting air duct is connected in series with the No. 7 regulating valve.

[0016] Furthermore, the air supply system includes an air supply fan, a primary air fan, a secondary air duct, an air preheater, a cold primary air main pipe, a hot primary air main pipe and a hot secondary air duct. The air preheater is installed at the end of the furnace flue. The air outlet of the air supply fan is connected to the No. 1 air inlet of the air preheater through a pipeline. The air outlet of the primary air fan is connected to the No. 2 air inlet of the air preheater through a pipeline. The air inlet end of the cold primary air main pipe is connected to the connecting pipe between the primary air fan and the air preheater. A plurality of primary air sub-ducts are provided, an air inlet end of each primary air sub-duct is connected to an air outlet end of a cold primary air main duct, an air outlet end of each cold primary air sub-duct is connected to an air inlet end of a coal mill, an air inlet end of a hot primary air main duct is connected to an air outlet end No. 1 of an air preheater, an air outlet end of a hot primary air main duct is connected to an air outlet end of a cold primary air main duct, an air inlet end of a hot secondary air duct is connected to an air outlet end No. 2 of an air preheater, and an air outlet end of a hot secondary air duct is connected to an air inlet end of a secondary air box;

[0017] The cold primary air main pipe is connected in series with a coal mill cold air regulating valve;

[0018] The hot primary air main pipe is connected in series with a coal mill hot air regulating valve;

[0019] A shut-off valve is connected in series on the primary air pipe;

[0020] Further, the air temperature supply air system includes a hot primary air supply air main pipe, a cold primary air supply air main pipe, a No. 1 cold primary air supply air duct, a No. 2 cold primary air supply air duct, a No. 1 hot primary air supply air duct and a No. 2 hot primary air supply air duct, the air inlet end of the hot primary air supply air main pipe is connected with the hot primary air main pipe, the No. 1 air outlet end of the hot primary air supply air main pipe is connected with the DC primary air channel through the No. 1 hot primary air supply air duct, the No. 2 air outlet end of the hot primary air supply air main pipe is connected with the DC primary air channel of the self-service stable combustion burner through the No. 2 hot primary air supply air duct, the air inlet end of the cold primary air supply air main pipe is connected with the cold primary air main pipe, the No. 1 air outlet end of the cold primary air supply air main pipe is connected with the No. 1 hot primary air supply air duct through the No. 1 cold primary air supply air duct, and the No. 2 air outlet end of the cold primary air supply air main pipe is connected with the No. 2 hot primary air supply air duct through the No. 2 cold primary air supply air duct;

[0021] A hot primary air regulating valve is connected in series on the hot primary air supply main pipe;

[0022] A cold primary air regulating valve is connected in series on the cold primary air supply main pipe;

[0023] A No. 1 cold primary air supply air regulating door is connected in series to the No. 1 cold primary air supply air duct;

[0024] The No. 2 cold primary air supply air duct is connected in series with a No. 2 cold primary air supply air regulating door;

[0025] The No. 1 hot primary air supply air duct is connected in series with a No. 2 shutoff valve, a No. 1 supply air regulating valve, a No. 1 wind speed measuring device and a No. 1 temperature measuring device in the gas direction, and the No. 2 shutoff valve, the No. 1 supply air regulating valve, the No. 1 wind speed measuring device and the No. 1 temperature measuring device are all located between the No. 1 cold primary air supply air duct and the DC primary air channel;

[0026] The No. 3 shutoff valve, No. 2 supply air regulating valve, No. 2 temperature measuring device and purge valve are connected in series in the No. 2 hot primary air supply air duct along the gas direction, and the No. 3 shutoff valve, No. 2 supply air regulating valve, No. 2 temperature measuring device and purge valve are all located between the No. 2 cold primary air supply air duct and the DC primary air channel of the self-service stable combustion burner;

[0027] The air temperature and air supply system also includes a heat exchanger, which is connected in series to the DC primary air channel of the self-service stable combustion burner. The heat exchange air inlet end of the heat exchanger is connected to the No. 2 hot primary air supply air duct through an induced draft duct, and the induced draft duct is located between the No. 2 temperature measuring device and the purge valve. A heat exchange valve is connected in series on the induced draft duct, and the heat exchange air return end of the heat exchanger is connected to the hot primary air main pipe through a heat exchanger return pipe;

[0028] Furthermore, a heater is connected in series to the hot primary air supply main pipe;

[0029] An efficient co - combustion method for direct - current burners and swirl burners. When the boiler operates under the condition of less than 15% of the rated load, the specific operation is as follows:

[0030] Shut off the first regulating valve and the fifth regulating valve, open the second regulating valve. The pulverized - coal air flow controls the primary air velocity entering the direct - current primary - air channel to u2 = 16 - 18 m / s by changing the opening of the third regulating valve. Without basically changing the original operation mode of the coal mill, the high - temperature and high - pressure hot primary air is provided to the air - temperature compensation air system by adjusting the hot primary - air regulating valve and the cold primary - air regulating valve. Open the second shut - off valve. By adjusting the opening of the first air - supply regulating valve and the first cold - primary - air supply regulating valve, control the hot primary - air volume and air temperature supplied to the direct - current primary - air channel. Among them, the air - supply velocity u1 is 30 - 32 m / s, the air - supply air temperature T1 is 280 - 300 °C. After the air - supply, it merges into the direct - current primary - air channel. At this time, the direct - current primary - air velocity u2 increases to 24 - 27 m / s, and the air - powder flow temperature increases from T3 = 50 - 90 °C to T3 = 180 - 210 °C. Through the above operations, by increasing the direct - current primary - air velocity, a large - range central recirculation zone is formed in the stable - combustion cavity and the furnace. The diameter D of the recirculation zone is 2De < D < 2.5De, and the length L is 4De < L < 4.5De;

[0031] Without changing the original operation mode of the coal mill, the high - temperature and high - pressure hot primary air is provided to the air - temperature compensation air system by adjusting the hot primary - air regulating valve and the cold primary - air regulating valve. Open the third shut - off valve. By adjusting the opening of the second air - supply regulating valve and the second cold - primary - air supply regulating valve, control the air temperature entering the second hot - primary - air supply pipeline. The air - supply air temperature T2 is 280 - 300 °C. Close the purging valve and open the heat - exchange valve to increase the air - powder mixture air temperature in the direct - current primary - air channel of the self - stabilizing combustion burner. The air - supply after heat - exchange then flows back to the hot - primary - air main pipe through the heat - exchanger return pipe. The air - powder flow temperature increases from T3 = 50 - 90 °C to T3 = 180 - 210 °C. Through the above operations, the air - powder flow temperature in the direct - current primary - air channel and the direct - current primary - air channel of the self - stabilizing combustion burner increases to 180 - 210 °C, thus achieving the purpose of increasing the primary air - powder temperature at the inlets of the direct - current burner and the self - stabilizing combustion burner when operating at less than 15% of the rated load.

[0032] The beneficial effects of this application compared with the prior art:

[0033] 1. The co - combustion device and co - combustion method for an efficient direct - current burner and swirl burner provided by the present invention achieve stable combustion of a tangentially - fired boiler with four - corner or eight - corner tangential circles at a super - low load of 15%, improving the deep - peak - shaving ability of the boiler;

[0034] At present, the power plant boiler adopts a coordinated combustion system of direct current burners and swirl burners. The lowest stable combustion load can reach 20%. When the boiler operates at 20% of the rated load, a central recirculation zone with a certain shape and size is generated. The diameter of the recirculation zone is 1.5De < D < 2De, the length is 3.5De < L < 4De, and the maximum flue gas recirculation volume is 7-8 times the primary air volume. It cannot meet the lower load peak shaving requirements. Practice shows that when the boiler operates at ultra-low load, the flue gas temperature in the main combustion zone decreases, and a large-sized recirculation zone is required to entrain more high-temperature flue gas to stabilize pulverized coal combustion. At the same time, increasing the primary air temperature can reduce the heat required for pulverized coal ignition, thereby improving the low-load stable combustion ability of the boiler.

[0035] In the present invention, a system for increasing the wind speed and temperature of the direct current burner and a supplementary air temperature system for the swirl burner are added to the coordinated combustion system of the direct current burner and the swirl burner, so as to increase the direct current primary air speed, thereby improving the entrainment ability of the direct current primary air, promoting more high-temperature flue gas to flow back to the recirculation zone of the self-stabilizing combustion burner, significantly enhancing the recirculation effect, and expanding the range of the recirculation zone. At 15% of the rated load, a large-scale central recirculation zone is formed in the stable combustion cavity and the furnace by increasing the direct current primary air speed. The diameter of the recirculation zone is 2De < D < 2.5De, the length is 4De < L < 4.5De, and the maximum flue gas recirculation volume is 9-10 times the primary air volume. The large-scale recirculation zone can provide a more stable high-temperature environment for combustion, which helps to maintain the stability of the flame. At the same time, by adding a system for increasing the wind speed and temperature of the direct current burner and a supplementary air temperature system for the swirl burner, the primary air-pulverized coal mixture can be increased from the original 50-90°C to 180-210°C significantly, significantly increasing the primary air-pulverized coal temperature at the inlets of the direct current burner and the self-stabilizing combustion burner, reducing the heat required for pulverized coal ignition, and strengthening the initial ignition of pulverized coal. Under the action of the large-scale recirculation zone as a high-temperature heat source and the significant increase in the primary air-pulverized coal temperature at the boiler inlet, the boiler can be ensured to stably burn at 15% of the rated load, and the deep peak shaving ability is improved.

[0036] 2. The coordinated combustion device and coordinated combustion method of the high-efficiency direct current burner and swirl burner provided by the present invention increase the primary air-pulverized coal temperature at the boiler inlet, effectively reduce the exhaust gas temperature, are beneficial to the complete combustion of pulverized coal, and thus improve the boiler efficiency;

[0037] The primary air carries and dries the pulverized coal, and provides an oxidant for the initial combustion of the pulverized coal. However, the internal structure of the coal mill is complex and the pulverized coal is easy to accumulate. In addition, due to the restrictions on the inlet wind temperature and explosion-proof requirements of the coal mill, the coal mill can only operate at a low temperature, and the outlet wind temperature generally does not exceed 100°C. When the total water content of the actual coal type is greater than the designed coal type, the outlet air-powder mixing temperature is lower, which affects the adaptability of the unit to the coal type. An increase in the intake of cold air will lead to an increase in the exhaust temperature. It has been verified that when the outlet air-powder mixing temperature of the coal mill increases from 76°C to 90°C, the exhaust temperature can be reduced by 9.8°C, and the power supply coal consumption can be reduced by about 1.5g / kW·h. In addition, a low pulverized coal mixing temperature will reduce the combustion rate, extend the ignition distance, affect the burnout of pulverized coal, and is not conducive to stable combustion. At the same time, when running at low load, as the amount of coal fed decreases, the heat released by the combustion of pulverized coal decreases, while the furnace volume remains unchanged, and the heating surface in the furnace remains unchanged, resulting in a decrease in the temperature of the furnace burner area. At 15% of the rated load, the temperature of the furnace burner area is lower than 900°C. A lower furnace temperature is not conducive to the combustion of pulverized coal.

[0038] The present invention increases the wind speed and wind temperature of the DC burner and the wind temperature supplement air system of the swirl burner on the coordinated combustion system of the DC burner and the swirl burner. On the basis of ensuring the safe operation of the pulverizing system, the primary air-powder mixture can be greatly increased from the original 50-90°C to 180-210°C, and the primary air-powder temperature at the inlet of the DC burner and the self-help stable combustion burner is significantly increased. The higher air-powder temperature can accelerate the combustion process of the coal powder, so that the combustible components in the coal powder are burned more fully, thereby improving the combustion efficiency. At the same time, the flue gas temperature in the large-scale central recirculation zone can reach more than 1300°C, which increases the temperature of the burner area, helps to reduce the incomplete combustion loss of the boiler, and improves the thermal efficiency of the boiler. At the same time, it can reduce the amount of cold air mixed into the coal mill, thereby reducing the exhaust temperature and improving the efficiency of the boiler.

[0039] 3. The invention provides a high-efficiency DC burner and swirl burner coordinated combustion device and coordinated combustion method, which effectively solves the problems of coal powder pipeline flashback, nozzle burning and coking, and water-cooled wall metal wall temperature overheating caused by low DC primary wind speed;

[0040] As the boiler load decreases, the amount of pulverized coal is gradually reduced and the pulverizer is shut down. The amount of pulverized coal fed into the furnace is greatly reduced, and the output of the pulverizer is greatly reduced, resulting in a decrease in the velocity of the primary air pulverized coal. At the same time, the power station boiler adopts a DC burner and a swirl burner coordinated combustion system, which mainly uses a pulverized coal distributor to take out a portion of the primary air pulverized coal mixture from the primary air duct of the DC burner and provide it to the self-help stable combustion burner. The self-help stable combustion burner needs to be put into operation at high and low loads. In order to prevent the difference in pipeline resistance from being too large, the same pipe diameter is usually used. This results in the original DC burner primary air duct being taken out of a portion of the primary air pulverized coal mixture, resulting in too low wind speed (16-18m / s), weakened rigidity of the pulverized coal airflow, easy to bend and deform, skewed against the wall, poor cutting circle organization, weak disturbance, slow combustion, and then leading to primary air nozzle burning and coking around the DC burner and water-cooled wall metal wall temperature overheating. At the same time, the original DC primary air pulverized coal airflow velocity in the pulverized coal pipeline is reduced, which may cause the mixture to accumulate in the pipeline and reach combustible conditions. When the mixture is ignited, the flame will propagate upstream of the pipeline, causing flashback and burning the pulverized coal pipeline.

[0041] The present invention increases the wind speed and wind temperature of the DC burner and the wind temperature supplement air system of the swirl burner on the DC burner and swirl burner coordinated combustion system, operates at 15% of the rated load of the boiler, and supplements the primary air channel of the DC burner by increasing the wind speed and wind temperature of the DC burner and the wind temperature supplement air system of the swirl burner, thereby eliminating the problem of too low wind speed in the primary air duct of the original DC burner due to the self-help stable combustion burner providing part of the primary air powder mixture. At the same time, the high-speed DC primary wind speed (24-27m / s, an increase of 50%) greatly improves the rigidity of the coal powder airflow, can prevent the coal powder from burning near the nozzle, and effectively solves the problems of DC burner nozzle burning, coking around the burner, and over-temperature of the water-cooled wall metal wall temperature, so as to ensure the safe and stable operation of the system. At the same time, the wind speed and temperature of the DC burner and the wind temperature of the swirl burner are increased. When the DC burner and swirl burner are put into operation and exited, the DC primary air channel and the DC primary air channel of the swirl burner are purged at high speed to avoid the deposition of coal powder in the pipeline, thereby alleviating the pipe blockage phenomenon and preventing the accumulation of air-powder mixture in the pipeline, causing flashback and burning the coal powder pipeline.

[0042] 4. The high-efficiency direct current burner and swirl burner cooperative combustion device and cooperative combustion method provided by the present invention can effectively improve the primary air powder temperature at the boiler inlet without substantially changing the original operation mode of the coal mill, prevent spontaneous combustion in the pipeline, and ensure safety;

[0043] Generally, the internal structure of a coal mill is complex and coal powder is easy to accumulate. In addition, due to the restrictions on the inlet air temperature and explosion-proof requirements of the coal mill, the coal mill can only operate at a low temperature, and the outlet air temperature generally does not exceed 100°C. When the total water content of the actual coal type is greater than the designed coal type, the outlet air-powder mixing temperature is lower, which leads to a low air-powder mixing temperature entering the burner. If the outlet temperature of the coal mill is increased, due to the long distance from the burner outlet, under high temperature conditions, the slow oxidation reaction is long enough and reaches the combustible condition, which is easy to cause spontaneous combustion in the pipeline and burn the coal powder pipeline.

[0044] The present invention adjusts the coal mill air intake volume by switching the door, adjusting the coal mill hot air regulating baffle and the coal mill cold air regulating baffle, and ensures that the original operation mode of the coal mill is basically unchanged by adjusting the hot primary air regulating door and the cold primary air regulating door, and provides high-temperature and high-pressure hot primary air to the DC burner wind speed and wind temperature and the swirl burner wind temperature supply air system. The DC burner wind speed and wind temperature supply air system is installed on the DC burner primary air channel, and the swirl burner wind temperature supply air system is installed on the self-help stable combustion burner DC primary air channel. Basically, it does not affect the coal mill inlet and outlet temperature and wind speed. The high-temperature and high-pressure hot primary air increases the air and powder temperature of the primary powder pipe, that is, under the premise of keeping the coal mill outlet temperature at 50-90°C, the temperature of the primary air and powder mixture entering the burner is as high as 180-210°C. Under the condition of ensuring that no spontaneous combustion occurs in the pipeline, the boiler inlet primary air and powder temperature is effectively improved.

[0045] 5. The invention provides a highly efficient direct current burner and swirl burner coordinated combustion device and coordinated combustion method, which can accurately control the heating temperature according to different types of coal;

[0046] In the pulverizing system, the characteristics of different types of coal vary greatly. The ignition temperature of coal is related to the volatile content. Generally, the ignition temperature of coal decreases with the increase of volatile content. The ignition temperature of lignite is usually 400-600℃, the ignition temperature of lean coal is usually around 700℃, and the ignition temperature of anthracite is usually above 800℃. Therefore, the requirements for heating temperature are different.

[0047] When burning bituminous coal with Vdaf>25%, the temperature of the primary air-powder mixture can reach 90-180℃; when burning lean coal with Vdaf of 10%-25%, the temperature of the primary air-powder mixture can reach 180-210℃; when burning anthracite with Vdaf<10%, the temperature of the primary air-powder mixture can reach 210-350℃. Among them, when a higher temperature cannot be achieved only by hot primary air, a heater can be arranged on the hot primary air supply air mother pipe to increase the temperature of the air supply air system entering the direct current burner wind speed and wind temperature and the swirl burner wind temperature, so that the temperature of the primary air-powder mixture can reach 210-350℃. Among them, the heating device is divided into a steam heater and a flue gas heater: the steam heater is a surface heater, and the heating heat source is taken from the steam at the outlet of the screen superheater, high-temperature superheater or high-temperature reheater. The flue gas heater is a surface heater or a mixed heater, and the heating heat source is taken from the flue gas at the outlet of the high-temperature superheater or high-temperature reheater. Electric heating can also be used. The above three heating methods have high heating efficiency, large temperature rise, flexibility, reliability and wide application range. Through precise control, the pulverizing system can quickly adjust the operating parameters according to the changes in coal types, provide the best pulverizing and combustion conditions for different coal types, and enhance the system's adaptability to coal types.

[0048] 6. The high-efficiency DC burner and swirl burner cooperative combustion device and cooperative combustion method provided by the present invention can increase the wind speed and temperature of the DC burner and the wind temperature and air supply system of the swirl burner can be switched to meet the different needs of the boiler.

[0049] When the DC burner and swirl burner coordinated combustion system is operating at more than 50% of the rated load, there is no need to increase the DC burner wind speed and wind temperature and the swirl burner wind temperature supplementary air system; when the DC burner and swirl burner coordinated combustion system is operating at 20%-50% of the rated load, it is necessary to increase the swirl burner primary air powder temperature and reduce the ignition heat of the coal powder to cooperate with the central reflow zone, making it easier to ignite the DC burner primary air powder flame. When operating at less than 15% of the rated load, it is necessary to increase the DC burner primary air powder wind speed and wind temperature and the swirl burner primary air powder temperature. At the same time, when the self-service stable combustion burner and the DC pulverized coal burner are withdrawn or put into operation, it is necessary to increase the DC burner wind speed and wind temperature and the swirl burner wind temperature supplementary air system to purge the pipeline.

[0050] The present invention realizes flexible switching operation of the air supply system for increasing the wind speed and wind temperature of the DC burner and the wind temperature of the swirl burner by changing the opening of the regulating door under different boiler requirements. According to the temperature requirement of the DC burner powder tube, the hot primary air regulating door and the cold primary air regulating door, the No. 1 supply air regulating valve, and the No. 1 cold primary air supply air regulating door are opened or reduced to jointly adjust the temperature and air volume of the hot primary air entering the DC primary air channel. The No. 2 shut-off valve realizes the disconnection and connection of the air supply system for increasing the wind speed and wind temperature of the DC burner and the wind temperature of the swirl burner entering the DC primary air channel. According to the temperature requirement of the self-service stable combustion burner powder tube, the No. 2 supply air regulating door and the No. 2 cold primary air supply air regulating door are opened or reduced to jointly adjust the heat exchange amount of the hot primary air entering the DC primary air channel of the self-service stable combustion burner. And by closing the purge valve and opening the heat exchange valve, the primary air in the DC primary air channel of the self-service stable combustion burner is heat exchanged, and the hot primary air after heat exchange is returned to the hot primary air mother pipe through the heat exchanger return pipe. The No. 3 shut-off valve is used to cut off and connect the DC primary air channel of the self-service stabilizing combustion burner, the air supply system for increasing the wind speed and wind temperature of the DC burner, and the air supply system for the swirl burner. The purge steps of the DC primary air channel of the self-service stabilizing combustion burner and the DC primary air channel can be performed by opening the purge door and the No. 2 shut-off valve to prevent the pulverized coal pipeline from being blocked or burned. The various parts of the air supply system for increasing the wind speed and wind temperature of the DC burner and the air supply system for the swirl burner can be adjusted and controlled independently to meet the needs of different locations and links for hot primary air supply and heat exchange. When the system needs to be connected, the regulating door can restore the air supply system for increasing the wind speed and wind temperature of the DC burner and the swirl burner and the burner system into an organic whole, ensuring the reasonable distribution and effective utilization of the hot primary air in the entire system.

[0051] 7. The present invention provides a high-efficiency DC burner and swirl burner cooperative combustion device and a cooperative combustion method, which monitors the temperature and air volume in real time through a temperature sensor and a wind speed measuring device to achieve precise control.

[0052] When only adjusting the opening of the regulating door of each pipeline, it is impossible to accurately grasp the actual situation of the air supply volume and the heat exchange amount. The present invention sets temperature and wind speed measuring points in the hot primary air supply pipeline, and sets temperature measuring points in the hot primary air supply pipeline, and can read the temperature data measured by the temperature sensor through the DSC interface to realize real-time monitoring of the heat exchange temperature. The wind speed data measured by the wind speed measuring device can be read through the DSC interface to realize real-time monitoring of the air supply volume. The opening of the regulating door of each pipeline is coordinated to realize accurate control of the temperature and air volume of the hot primary air that needs to be supplemented and heat exchanged. The temperature and wind speed measuring points are set in the DC primary air channel, and the temperature measuring points are set in the DC primary air channel of the self-service stable combustion burner, and the temperature data measured by the temperature sensor can be read through the DSC interface to realize real-time monitoring of the heat exchange temperature. The wind speed data measured by the wind speed measuring device can be read through the DSC interface to realize real-time monitoring of the air supply volume. The opening of the regulating door of each pipeline is coordinated to realize accurate control of the temperature and air volume of the DC primary air after the air supply is realized and accurate control of the temperature of the primary air of the self-service stable combustion burner after the heat exchange. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a schematic diagram of the four-corner tangential circle ignition principle of the cooperative combustion device described in this application;

[0054] Figure 2 A side view showing the arrangement of the self-help combustion stabilizing burner in the cooperative combustion device described in the present application;

[0055] Figure 3 This is a front view of the arrangement of the self-help combustion stabilizing burner in the cooperative combustion device described in this application;

[0056] Figure 4 This is a schematic diagram of the arrangement of the wind temperature and air supply system in the cooperative combustion device described in this application;

[0057] Figure 5 This is a schematic diagram of the morphology of the combustion chamber and the reflow zone in the furnace of the self-help combustion stabilizing burner of the cooperative combustion device described in this application after air supplementation;

[0058] Figure 6 This is a schematic diagram of the structure of the wind speed measuring device in the cooperative combustion device described in this application;

[0059] Figure 7 This is a schematic diagram of the structure of the temperature sensor in the cooperative combustion device described in this application;

[0060] Figure 8 It is a schematic diagram of the arrangement of the wind temperature replenishment system containing a heater in the cooperative combustion device described in this application;

[0061] Fig. 9 This is a schematic diagram of the arrangement of a wind temperature supplementary air system in the cooperative combustion device described in this application;

[0062] Fig.10 This is a schematic diagram of the arrangement of two wind temperature and air supply systems in the cooperative combustion device described in this application;

[0063] Fig.11 This is a schematic diagram of the layout of three wind temperature replenishment systems in the cooperative combustion device described in this application. DETAILED DESCRIPTION

[0064] Specific implementation method 1: Combination Figures 1 to 11 The present embodiment is described. In the present embodiment, a high-efficiency DC burner and swirl burner cooperative combustion device is provided. The cooperative combustion device includes a four-corner cut pulverized coal combustion boiler 11, a secondary wind box 31 and four DC pulverized coal burners 10. The four DC pulverized coal burners 10 are respectively arranged at the four corners of the four-corner cut pulverized coal combustion boiler 11. Each DC pulverized coal burner 10 corresponds to at least one coal mill 21. The DC primary air nozzle 1 in the DC pulverized coal burner 10 is connected to the coal outlet end of the coal mill 21 through a coal supply pipeline. The DC secondary air nozzle 3 in the DC pulverized coal burner 10 is connected to the air outlet end of the secondary wind box 31 through an air supply pipeline. At least one self-help stabilizing combustion burner 2 is arranged in each DC pulverized coal burner 10, and Each self-help stabilizing combustion burner 2 is arranged between the DC primary air nozzle 1 and the DC secondary air nozzle 3 located on the same layer in the corresponding DC pulverized coal burner 10. The self-help stabilizing combustion burner 2 is connected to the coal supply pipeline of the adjacent DC primary air nozzle 1 and the air supply pipeline of the adjacent DC secondary air nozzle 3 through the air-powder system. The coordinated combustion device also includes an air supply system and a wind temperature and air supply system 63. The No. 1 air outlet end of the air supply system is connected to the air inlet end of each coal mill 21, the No. 2 air outlet end of the air supply system is connected to the air inlet end of the secondary air box 31, the air inlet end of the wind temperature and air supply system 63 is connected to the air supply system, the DC air supply end of the wind temperature and air supply system 63 is connected to the coal supply pipeline, and the swirl air supply end of the wind temperature and air supply system 63 is connected to the air-powder system;

[0065] Each coal mill 21 is equipped with a corresponding coal feeder 19, and the coal outlet of each coal feeder 19 is connected to the coal inlet of the corresponding coal mill 21 through a coal drop pipe 20;

[0066] The coal supply pipeline includes a DC primary air channel 5, a primary air duct 22 and a No. 1 regulating valve 23. One end of the DC primary air channel 5 is connected to the corresponding DC primary air nozzle 1, one end of the primary air duct 22 is connected to the coal outlet end of the corresponding coal mill 21, and the other end of the DC primary air channel 5 is connected to the other end of the primary air duct 22. A No. 1 regulating valve 23 is installed at the connection between the DC primary air channel 5 and the primary air duct 22. A No. 3 temperature measuring device 54 and a No. 3 air volume speed measuring device 55 are sequentially arranged on the DC primary air channel 5 along the air flow direction.

[0067] The coal supply pipeline also includes a No. 2 regulating valve 25, a No. 3 regulating valve 26, a No. 1 pulverized coal pipeline 27 and a pulverized coal separation device 28. The coal inlet end of the pulverized coal separation device 28 is connected to the primary air duct 22, and the No. 2 regulating valve 25 is connected in series to the primary air duct 22. The No. 1 coal outlet end of the pulverized coal separation device 28 is connected to the DC primary air channel 5 through the No. 1 pulverized coal pipeline 27, and the No. 3 regulating valve 26 is connected in series to the No. 1 pulverized coal pipeline 27.

[0068] The air supply pipeline includes a DC secondary air channel 7, a secondary air channel 32 and a No. 4 regulating valve 34. One end of the DC secondary air channel 7 is connected to the corresponding DC secondary air nozzle 3, one end of the secondary air channel 32 is connected to the air outlet end of the corresponding secondary air box 31, and the other end of the DC secondary air channel 7 is connected to the other end of the secondary air channel 32. A No. 4 regulating valve 34 is installed at the connection between the DC secondary air channel 7 and the secondary air channel 32.

[0069] The self-help combustion stabilizing burner 2 comprises a combustion stabilizing chamber 4, a secondary air channel 6 in a swirl flow, and a DC primary air channel 8 of the self-help combustion stabilizing burner. The secondary air channel 6 in a swirl flow is coaxially sleeved on the outside of the DC primary air channel 8 of the self-help combustion stabilizing burner, and one end of the DC primary air channel 8 of the self-help combustion stabilizing burner and one end of the secondary air channel 6 in a swirl flow are both connected to the combustion stabilizing chamber 4, and the other end of the DC primary air channel 8 of the self-help combustion stabilizing burner is connected to the coal supply pipeline through an air-powder system, and the other end of the secondary air channel 6 in a swirl flow is connected to the air supply pipeline through an air-powder system. The pipeline is connected, an axial blade group 9 is provided between the self-service stabilizing combustion burner DC primary air channel 8 and the swirl internal secondary air channel 6, and the axial blade group 9 is arranged close to the stabilizing combustion chamber 4, and the axial blade group 9 includes a plurality of axial blades, and the plurality of axial blades are equidistantly arranged along the circumferential direction between the self-service stabilizing combustion burner DC primary air channel 8 and the swirl internal secondary air channel 6, and one end of each axial blade is connected to the outer wall of the self-service stabilizing combustion burner DC primary air channel 8, and the other end of each axial blade is connected to the inner wall of the swirl internal secondary air channel 6;

[0070] The air-powder system includes a DC coal supply pipeline and a swirl air supply pipeline. The coal supply pipeline is connected to the DC primary air channel 8 of the self-help stable combustion burner through the DC coal supply pipeline, and the air supply pipeline is connected to the secondary air channel 6 in the swirl through the swirl air supply pipeline.

[0071] The DC coal supply pipeline includes a DC connection air duct of the self-service stable combustion burner, a No. 5 regulating valve 24, a No. 2 coal powder channel 29 and a No. 6 regulating valve 30. The primary air duct 22 is connected with the DC primary air channel 8 of the self-service stable combustion burner through the DC connection air duct of the self-service stable combustion burner, and the No. 5 regulating valve 24 is connected in series to the DC connection air duct of the self-service stable combustion burner. The No. 2 coal outlet end of the coal powder separation device 28 is connected with the DC primary air channel 8 of the self-service stable combustion burner through the No. 2 coal powder channel 29, and the No. 6 regulating valve 30 is connected in series to the No. 2 coal powder channel 29;

[0072] The swirl air supply pipeline includes a self-service stabilizing combustion burner swirl connecting air duct and a No. 7 regulating valve 33. The secondary air duct 32 is connected to the secondary air channel 6 in the swirl through the self-service stabilizing combustion burner swirl connecting air duct. The No. 7 regulating valve 33 is connected in series at the connecting point between the secondary air channel 6 in the swirl and the self-service stabilizing combustion burner connecting air duct.

[0073] The air supply system includes a blower 14, a primary blower 15, a secondary air duct 16, an air preheater 17, a cold primary air main pipe 35, a hot primary air main pipe 36 and a hot secondary air duct 37. The air preheater 17 is installed at the end of the furnace flue 18. The air outlet of the blower 14 is connected to the No. 1 air inlet of the air preheater 17 through a pipeline. The air outlet of the primary blower 15 is connected to the No. 2 air inlet of the air preheater 17 through a pipeline. The air inlet of the cold primary air main pipe 35 is connected to the connecting pipe between the primary blower 15 and the air preheater 17. A plurality of primary air sub-tubes are provided on the air outlet end, an air inlet end of each primary air sub-tube is connected to the air outlet end of the cold primary air main tube 35, the air outlet end of each cold primary air sub-tube is connected to the air inlet end of a coal mill 21, the air inlet end of the hot primary air main tube 36 is connected to the No. 1 air outlet end of the air preheater 17, the air outlet end of the hot primary air main tube 36 is connected to the air outlet end of the cold primary air main tube 35, the air inlet end of the hot secondary air duct 37 is connected to the No. 2 air outlet end of the air preheater 17, and the air outlet end of the hot secondary air duct 37 is connected to the air inlet end of the secondary air box 31;

[0074] The cold primary air main pipe 35 is connected in series with a coal mill cold air regulating valve 56;

[0075] The hot primary air main pipe 36 is connected in series with a coal mill hot air regulating valve 57;

[0076] A shut-off valve 58 is connected in series on the primary air pipe;

[0077] The air temperature supply air system 63 includes a hot primary air supply air main pipe 38, a cold primary air supply air main pipe 39, a No. 1 cold primary air supply air duct 40, a No. 2 cold primary air supply air duct 41, a No. 1 hot primary air supply air duct 42 and a No. 2 hot primary air supply air duct 43. The air inlet end of the hot primary air supply air main pipe 38 is connected to the hot primary air main pipe 36, and the No. 1 air outlet end of the hot primary air supply air main pipe 38 is connected to the DC primary air channel 5 through the No. 1 hot primary air supply air duct 42. The No. 2 air outlet end of 8 is connected with the DC primary air channel 8 of the self-help stable combustion burner through the No. 2 hot primary air supply air duct 43, the air inlet end of the cold primary air supply air mother pipe 39 is connected with the cold primary air mother pipe 35, the No. 1 air outlet end of the cold primary air supply air mother pipe 39 is connected with the No. 1 hot primary air supply air duct 42 through the No. 1 cold primary air supply air duct 40, and the No. 2 air outlet end of the cold primary air supply air mother pipe 39 is connected with the No. 2 hot primary air supply air duct 43 through the No. 2 cold primary air supply air duct 41;

[0078] A hot primary air regulating valve 44 is connected in series to the hot primary air supply main pipe 38;

[0079] A cold primary air regulating valve 45 is connected in series to the cold primary air supply air main pipe 39;

[0080] A number one cold primary air supply air regulating door 46 is connected in series to the number one cold primary air supply air duct 40;

[0081] A No. 2 cold primary air supply air regulating door 47 is connected in series to the No. 2 cold primary air supply air duct 41;

[0082] The No. 1 hot primary air supply air duct 42 is connected in series with a No. 2 shutoff valve 59, a No. 1 supply air regulating valve 61, a No. 1 wind speed measuring device 49 and a No. 1 temperature measuring device 48 in sequence along the gas direction, and the No. 2 shutoff valve 59, the No. 1 supply air regulating valve 61, the No. 1 wind speed measuring device 49 and the No. 1 temperature measuring device 48 are all located between the No. 1 cold primary air supply air duct 40 and the DC primary air channel 5;

[0083] The No. 3 shutoff valve 60, the No. 2 supply air regulating valve 62, the No. 2 temperature measuring device 50 and the purge valve 51 are connected in series in the No. 2 hot primary air supply air duct 43 in the gas direction, and the No. 3 shutoff valve 60, the No. 2 supply air regulating valve 62, the No. 2 temperature measuring device 50 and the purge valve 51 are all located between the No. 2 cold primary air supply air duct 41 and the self-help stable combustion burner DC primary air channel 8;

[0084] The air temperature supply air system 63 also includes a heat exchanger 53, which is connected in series to the DC primary air channel 8 of the self-service stable combustion burner. The heat exchange air inlet end of the heat exchanger 53 is connected to the No. 2 hot primary air supply air duct 43 through an induced draft pipe, and the induced draft pipe is located between the No. 2 temperature measuring device 50 and the purge valve 51. A heat exchange valve 66 is connected in series to the induced draft pipe. The heat exchange air return end of the heat exchanger 53 is connected to the hot primary air mother pipe 36 through a heat exchanger return pipe 65.

[0085] A heater 64 is also connected in series to the hot primary air supply main pipe 38.

[0086] In this embodiment, a high-efficiency direct current burner and swirl burner cooperative combustion device is provided, wherein the direct current pulverized coal burner 10 in the four-corner tangential pulverized coal combustion boiler 11 is arranged at the four corners of the furnace, and the outlet of the direct current pulverized coal burner 10 is composed of a group of rectangular nozzles. The primary air pulverized coal airflow and the secondary air required for combustion are sprayed into the furnace in the form of direct current jets by different nozzles, and the direct current primary air nozzle 1 and the direct current secondary air nozzle 3 are arranged alternately. The upstream adjacent corner flame is ignited at the root of the downstream direct current pulverized coal burner 10 to form an actual flame zone 12, and an imaginary tangential circle 13 is formed in the center of the four-corner tangential pulverized coal combustion boiler; four self-help stable combustion burners 2 are arranged at the four corners between the direct current primary air nozzle 1 of the direct current pulverized coal burner 10 and the direct current secondary air nozzle 3 of the direct current pulverized coal burner 10. The self-help combustion stabilizing burner 2 is composed of the self-help combustion stabilizing burner DC primary air channel 8, the swirl internal secondary air channel 6 and the combustion stabilizing chamber 4 from the inside to the outside; the self-help combustion stabilizing burner DC primary air channel 8 and the swirl internal secondary air channel 6 are coaxially arranged and set at the front end of the combustion stabilizing chamber 4, and are flush with the inner wall of the combustion stabilizing chamber 4. The outlet end of the combustion stabilizing chamber 4 is flush with the outlet ends of the DC primary air nozzle 1 and the DC secondary air nozzle 3, and 16 60° axially curved blades 9 are installed in the swirl internal secondary air channel 6; the specific working process of this application is as follows:

[0087] After the primary air is pressurized by the primary fan, it passes through the air preheater 17, the hot primary air main pipe 36, and the coal mill hot air regulating baffle 57 to provide hot air to the coal mill 21 for coal powder drying and transportation. It passes through the cold primary air main pipe 35 and the coal mill cold air regulating valve 56 to provide cold air to the coal mill to adjust the temperature of the hot primary air entering the coal mill. The coal mill air intake is adjusted by adjusting the coal mill hot air regulating valve 57 and the coal mill cold air regulating valve 56, and the path is cut off and connected by the No. 1 shut-off valve 58. In the wind temperature supply air system 63, a part of the hot primary air is drawn out from the hot primary air main pipe 36, passes through the hot primary air regulating door 44 and the hot primary air supply air main pipe 38 in sequence, and is divided into two paths. One path passes through the No. 2 shut-off valve 59, the No. 1 hot primary air supply air pipeline 42, and the No. 1 supply air regulating door 61, and then merges into the DC primary air channel 5 to heat the DC primary air. This working process is to improve the wind speed and wind temperature subsystem of the DC burner. One path passes through the No. 3 shut-off valve 60, the No. 2 hot primary air supply air pipeline 43, and the No. 2 supply air regulating valve 62, and is divided into two paths: one path passes through the heat exchange valve 66, the heat exchanger 53, and the heat exchanger return pipe 65 and then returns to the hot primary air main pipe 36 to heat the DC primary air of the self-service stabilizing combustion burner; one path passes through the purge valve 51 and merges into the DC primary air channel 8 of the self-service stabilizing combustion burner to purge the DC primary air channel 8 of the self-service stabilizing combustion burner. This working process is to improve the wind temperature supply air system of the swirl burner. A part of the cold primary air is drawn out from the cold primary air main pipe 35 and is divided into two paths after passing through the cold primary air regulating valve 45 and the cold primary air supply air main pipe 39 in sequence. One path passes through the No. 1 cold primary air supply air regulating valve 46 and then merges into the No. 1 hot primary air supply air duct 42 to regulate the air temperature in the No. 1 hot primary air supply air duct 42; the other path passes through the No. 2 cold primary air supply air regulating door 47 and then merges into the No. 2 hot primary air supply air duct 43 to regulate the air temperature in the No. 2 hot primary air supply air duct 43.

[0088] After being pressurized by the blower 14, the secondary air passes through the secondary air duct 16, the air preheater 17, the hot secondary air duct 37, and the secondary air box 31 in sequence, and enters the secondary air duct 32. The outlet of the secondary air duct 32 is divided into two paths: one path flows through the regulating door 33 and enters the secondary air channel 6 in the swirl, and then flows through the axially curved blades 9 in the channel and enters the stable combustion chamber 4 in a rotating form; the other path flows through the regulating door 34 and enters the DC secondary air channel 7, and enters the furnace in a DC form.

[0089] After passing through the coal mill 21, the primary air powder enters the primary air main pipe 22 and is divided into three paths: one path enters the DC primary air channel 5 through the No. 1 regulating valve 23, and is mixed with the hot primary air of the No. 1 hot primary air supply air duct 42, and is sprayed into the furnace in a DC form; one path enters the coal powder distributor 28 through the No. 2 regulating valve 25; one path enters the DC primary air channel 8 of the self-service stable combustion burner through the No. 5 regulating valve 24, and is heat-exchanged with the hot primary air of the heat exchanger 53, and is sprayed into the stable combustion chamber 4 in a DC form; the air-powder mixture is divided into two paths after passing through the coal powder distributor 28, one path enters the No. 1 coal powder pipeline 27 through the No. 3 regulating valve 26, and then flows through the DC primary air channel 5, and is mixed with the hot primary air of the No. 1 hot primary air supply air duct 42, and is sprayed into the furnace in a DC form; one path enters the No. 2 coal powder channel 29 through the No. 6 regulating valve 30, and then flows through the DC primary air channel 8 of the self-service stable combustion burner, and is heat-exchanged with the hot primary air of the heat exchanger 53, and is sprayed into the stable combustion chamber 4 in a DC form. Under the action of the secondary air in the swirl and the stable combustion chamber 4, the primary air powder forms a stable reflux zone in the center of the stable combustion chamber and enters the furnace in the form of a reflux zone.

[0090] Among them, the coal mill cold air regulating valve 56 and the coal mill cold air regulating valve 57 jointly regulate the temperature and air volume entering the coal mill. The No. 1 shut-off valve 58 realizes the cutting off and connecting of the air volume entering the coal mill 21. The hot primary air regulating door 44 arranged on the hot primary air supply air main pipe 38 and the cold primary air regulating door 45 arranged on the cold primary air supply air main pipe 39 jointly regulate the air volume and temperature entering the inlet of the supply air system 63 for increasing the wind speed and wind temperature of the DC burner and the wind temperature of the swirl burner. The No. 1 supply air regulating door 61 arranged on the No. 1 hot primary air supply air duct 42 and the No. 1 cold primary air supply air regulating door 46 arranged on the No. 1 cold primary air supply air duct 40 jointly regulate the temperature and air volume of the hot primary air entering the DC primary air channel 5. The No. 2 shut-off valve 59 realizes the cutting off and connecting of the supply air system for increasing the wind speed and wind temperature of the DC burner and the wind temperature of the swirl burner entering the DC primary air channel 5. The No. 2 supply air regulating door 62 arranged on the No. 2 hot primary air supply air duct 43 and the No. 2 cold primary air supply air regulating door 47 arranged on the No. 2 cold primary air supply air duct 41 jointly regulate the air volume and temperature of the supply air system for increasing the wind speed and temperature of the DC burner and the wind temperature of the swirl burner entering the DC primary air channel 8 of the self-service stable combustion burner. Among them, the purge valve 51 is used to adjust the purge step of the DC primary air channel 8 of the self-service stable combustion burner; the heat exchange valve 66 is used to adjust the heat exchange amount of the DC primary air channel 8 of the self-service stable combustion burner. The No. 3 shut-off valve 60 realizes the disconnection and connection of the supply air system for increasing the wind speed and temperature of the DC burner and the wind temperature of the swirl burner entering the DC primary air channel 8 of the self-service stable combustion burner. The No. 1 air supply regulating valve 61 and the No. 1 regulating valve 23 set on the DC primary air channel 5 and the regulating gate 26 set on the No. 1 powder channel 27 jointly regulate the DC primary air speed. The No. 2 air supply regulating valve 62 and the No. 6 regulating valve 30 set on the No. 2 coal powder channel 29 and the No. 5 regulating valve 24 set on the DC primary air channel 8 of the self-service stable combustion burner jointly regulate the DC primary air speed of the self-service stable combustion burner. The No. 7 regulating valve 33 is set on the secondary air channel 6 in the swirl to regulate the secondary air speed in the swirl, and the No. 4 regulating valve 34 is set on the DC secondary air channel 7 to regulate the DC secondary air speed.

[0091] Wind speed measurement: insert the wind speed measuring device vertically into the pipe wall. When the primary wind flows, measure the total pressure on the windward side and the static pressure on the leeward side. Collect the total pressure and static pressure of the airflow and transmit them to the wind speed sensor. Detect the pressure at the +- end of the differential pressure transmitter. Connect it to the DCS industrial control system to display the wind speed and air volume, so as to control the wind speed to achieve the desired purpose. The temperature sensor is fixed through the support tube on the outer wall of the pipeline. Some temperature measuring elements and protective sleeves are extended into the inner wall of the pipeline for temperature measurement. The temperature measuring element can transmit the temperature signal to DSC in real time, and the temperature information in the pipeline is monitored through DSC.

[0092] Specific implementation method 2: Combination Figures 1 to 11This embodiment provides a collaborative combustion method for an efficient direct - current burner and a swirl burner when the boiler operates under a condition of less than 15% of the rated load. The specific operation method is as follows:

[0093] Shut off the first regulating valve 23 and the fifth regulating valve 24, open the second regulating valve 25. The pulverized coal air flow controls the primary air velocity entering the direct - current primary air passage 5 to u2 = 16 - 18 m / s by changing the opening of the third regulating valve 26. By adjusting the hot primary air regulating valve 44 and the cold primary air regulating valve 45, while basically not changing the original operation mode of the coal mill, high - temperature and high - pressure hot primary air is provided to the air temperature compensation system 63. Open the second shut - off valve 59. By adjusting the opening of the first air supply regulating valve 61 and the first cold primary air supply regulating valve 46, control the hot primary air volume and air temperature supplied to the direct - current primary air passage. Among them, the air supply velocity u1 is 30 - 32 m / s, and the air supply temperature T1 is 280 - 300 °C. After air supply, it converges into the direct - current primary air passage 5. At this time, the direct - current primary air velocity u2 increases to 24 - 27 m / s, and the temperature of the air - powder flow increases from T3 = 50 - 90 °C to T3 = 180 - 210 °C. Through the above operations, by increasing the direct - current primary air velocity, a large - range central recirculation zone is formed in the stable combustion chamber 4 and the furnace. The diameter D of the recirculation zone is 2De < D < 2.5De, and the length L is 4De < L < 4.5De;

[0094] By adjusting the hot primary air regulating valve 44 and the cold primary air regulating valve 45, while not changing the original operation mode of the coal mill, high - temperature and high - pressure hot primary air is provided to the air temperature compensation system 63. Open the third shut - off valve 60. By adjusting the opening of the second air supply regulating valve 62 and the second cold primary air supply regulating valve 47, control the air temperature entering the second hot primary air supply pipeline 43. The air supply temperature T2 is 280 - 300 °C. Close the purge valve 51, open the heat exchange valve 66, to increase the air - powder mixture air temperature in the direct - current primary air passage 8 of the self - stabilizing combustion burner. The air supply after heat exchange then flows back to the hot primary air header 36 through the heat exchanger return pipe 65. The air - powder flow temperature increases from T3 = 50 - 90 °C to T3 = 180 - 210 °C. Through the above operations, the air - powder flow temperature in the direct - current primary air passage 5 and the direct - current primary air passage 8 of the self - stabilizing combustion burner increases to 180 - 210 °C, so as to achieve the purpose of increasing the primary air - powder temperature at the inlets of the direct - current burner and the self - stabilizing combustion burner when operating at less than 15% of the rated load.

[0095] The collaborative combustion method provided in this embodiment is for use when the boiler operates under a condition of less than 15% of the rated load. The attached drawings Figure 4A schematic diagram of the morphology of the combustion stabilizing chamber and the recirculation zone in the furnace of the self-help combustion stabilizing burner after air supply in the present invention; in the figure, T1 is the wind temperature measured by the No. 1 temperature measuring device 48 arranged on the No. 1 hot primary air supply air duct 42; T2 is the wind temperature measured by the No. 2 temperature sensor 50 arranged on the No. 2 hot primary air supply air duct 43; T3 is the wind temperature measured by the No. 3 temperature sensor 54 arranged on the DC primary air channel 5; T4 is the wind temperature measured by the No. 4 temperature sensor 52 arranged on the DC primary air channel 8 of the self-help combustion stabilizing burner; u1 is the wind speed measured by the No. 1 wind speed measuring device 49 arranged on the No. 1 hot primary air supply air duct 42; u2 is the wind speed measured by the No. 2 wind speed measuring device 55 arranged on the DC primary air channel 5; De is the inner secondary air diameter; L is the recirculation zone length; D is the recirculation zone diameter. Among them, under 15% rated load, the DC primary air velocity u2 in the DC primary air channel 5 after air supply is in the range of 24-27m / s, the swirl secondary air velocity in the swirl secondary air channel 6 is in the range of 35-40m / s, and the DC secondary air velocity in the DC secondary air duct 32 is in the range of 30-35m / s. The DC primary air temperature T3 in the DC primary air channel 5 after air supply is in the range of 180-210℃, and the DC primary air temperature T4 in the DC primary air channel 8 of the self-help stable combustion burner after air supply is in the range of 180-210℃.

[0096] The present application can also realize high-temperature and high-pressure purging of the DC primary air channel 8 and the DC primary air channel 5 of the self-service stabilizing combustion burner by introducing the wind temperature and air supply system 63 to prevent the coal powder pipeline from being blocked or burned. The specific operation is: when the self-service stabilizing combustion burner 2 and the DC burner 10 are withdrawn or put into operation, the purging steps of the DC primary air channel 8 and the DC primary air channel 5 of the self-service stabilizing combustion burner can be performed by opening the No. 3 shut-off valve 60, opening the purge valve 51, closing the heat exchange valve 66 and opening the No. 2 shut-off door 59 respectively. The monitoring personnel should pay attention to monitoring the wind speed of each powder pipe (>18m / s). If the wind speed continues to drop below 18m / s, the burner system is cut off, and the air supply system for increasing the wind speed and wind temperature of the DC burner and the wind temperature of the swirl burner is opened for purging (the purge wind speed is generally above 20m / s). After 10 minutes of purging, the air supply system for increasing the wind speed and wind temperature of the DC burner and the wind temperature of the swirl burner is closed. When the self-stable combustion burner 2 and the DC burner 10 are withdrawn or put into operation, the air supply system for increasing the wind speed and temperature of the DC burner and the wind temperature of the swirl burner is opened for purging. The powder pipes are purged one by one. When purging, pay attention to the wind speed and keep it above 25m / s. The purging time is increased to 20min. This is to prevent the coal powder pipeline from being blocked or burned. It is to prevent the accumulation of air-powder mixture in the pipeline, causing flashback and burning the coal powder pipeline.

[0097] The present invention has been disclosed as above with preferred implementation cases, but it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above implementation cases based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention. Specific embodiment:

[0099] This technology has been applied to a 600MW subcritical pressure drum boiler, which adopts a four-corner tangential combustion method. Four self-help stable combustion burners are arranged at the four corners between the DC primary air nozzle and the DC secondary air nozzle of the second-layer DC pulverized coal burner. Powder is taken from the branch pipe of the third-layer pulverizing system, and air is taken from the secondary wind box. Before the burner modification, the minimum non-oil stable combustion load of the boiler is 20%. The air and powder temperature at the outlet of the coal mill is 65℃, the inlet temperature of the burner is 63℃, and the inlet air temperature of the coal mill is about 240℃. There is a problem of powder blocking in the DC primary air duct, which affects the stability of boiler combustion, reduces the output of the unit, and even causes fire extinguishing. In severe cases, it causes coal powder to spontaneously ignite and burn the air duct. The cost caused by pipeline burning is about more than 1 million yuan. When the boiler was shut down for maintenance after one year of stable operation, it was found that there were partial burning and slagging problems at the nozzles of the DC burner and the self-help stable combustion burner.

[0100] By adopting the device and method involved in the present invention, after adding a DC burner and swirl burner coordinated combustion system to increase the wind speed and wind temperature of the DC burner and the wind temperature supplement air system 63 of the swirl burner, the minimum load of the boiler without oil injection and stable combustion can reach 15%. When operating at 15% of the rated load, the hot primary air and cold primary air supplement air heat exchange technology is adopted to increase the primary wind speed of the DC burner, thereby improving the DC wind injection capacity. After air supplement, the DC primary wind speed in the DC primary air channel 5 can reach 24-27m / s, and the DC primary air temperature range in the DC primary air channel 5 after air supplement is 180-210℃. After heat exchange, the DC primary air temperature in the DC primary air channel 8 of the self-help stable combustion burner is 180-210℃. The carbon content of the fly ash of the boiler is reduced from 6% before the transformation to 4.4%, and the boiler efficiency is increased from 92.9% before the transformation to 94.1%. The problem of pipeline blockage and powder blockage is completely solved, and the loss is reduced. The above saves a total of 2 million yuan.

[0101] Under the requirement of "giving full play to the emergency peak-shaving capacity of existing coal-fired power units", the deep regulation load of thermal power units will be further reduced, and the deep regulation time will be greatly increased. In order to encourage thermal power units to reduce the deep regulation load to below 30% of the rated load, various regions have adopted a step-by-step quotation incentive policy, and set a higher quotation ceiling for the load rate of units below 30%. Taking the incentive policy of Heilongjiang Province as an example, when the load rate reaches below 25%, the price can be declared at 0.7-1 yuan / kwh. The use of the present invention "a method and device for improving the coordinated combustion capacity of direct current burners and swirl burners" can achieve stable combustion at 15% of the rated load. It can be comprehensively obtained that the deep regulation of the burner after the transformation can generate 80-85 million yuan more income than before the transformation.

Claims

1. A high-efficiency direct current burner and swirl burner coordinated combustion device, the coordinated combustion device comprising a four-corner tangential pulverized coal combustion boiler (11), a secondary wind box (31) and four direct current pulverized coal burners (10), the four direct current pulverized coal burners (10) are respectively arranged at the four corners of the four-corner tangential pulverized coal combustion boiler (11), each direct current pulverized coal burner (10) corresponds to at least one coal mill (21), and the direct current primary air nozzle (1) in the direct current pulverized coal burner (10) is supplied with coal. The pipeline is connected to the coal outlet end of the coal mill (21), the DC secondary air nozzle (3) in the DC pulverized coal burner (10) is connected to the air outlet end of the secondary air box (31) through the air supply pipeline, each DC pulverized coal burner (10) is arranged with at least one self-help combustion stabilizing burner (2), and each self-help combustion stabilizing burner (2) is arranged between the DC primary air nozzle (1) and the DC secondary air nozzle (3) located on the same layer in the corresponding DC pulverized coal burner (10), characterized in that: The self-help stable combustion burner (2) is connected to the coal supply pipeline adjacent to the DC primary air nozzle (1) and the air supply pipeline adjacent to the DC secondary air nozzle (3) through the air-powder system. The coordinated combustion device also includes an air supply system and an air temperature supply air system (63). The No. 1 air outlet end of the air supply system is connected to the air inlet end of each coal mill (21), the No. 2 air outlet end of the air supply system is connected to the air inlet end of the secondary air box (31), the air inlet end of the air temperature supply air system (63) is connected to the air supply system, the DC supply air end of the air temperature supply air system (63) is connected to the coal supply pipeline, and the swirl supply air end of the air temperature supply air system (63) is connected to the air-powder system.

2. A high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 1, characterized in that: Each coal mill (21) is correspondingly equipped with a coal feeder (19), and the coal outlet end of each coal feeder (19) is connected to the coal inlet end of the corresponding coal mill (21) through a coal drop pipe (20).

3. The high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 2, characterized in that: The coal supply pipeline comprises a DC primary air channel (5), a primary air duct (22) and a first regulating valve (23); one end of the DC primary air channel (5) is connected to a corresponding DC primary air nozzle (1); one end of the primary air duct (22) is connected to a coal outlet end of a corresponding coal mill (21); the other end of the DC primary air channel (5) is connected to the other end of the primary air duct (22); and the first regulating valve (23) is installed at the connection point between the DC primary air channel (5) and the primary air duct (22); The coal supply pipeline further comprises a No. 2 regulating valve (25), a No. 3 regulating valve (26), a No. 1 pulverized coal pipeline (27) and a pulverized coal separation device (28); the coal inlet end of the pulverized coal separation device (28) is connected to the primary air duct (22), and the No. 2 regulating valve (25) is connected in series to the primary air duct (22); the No. 1 coal outlet end of the pulverized coal separation device (28) is connected to the DC primary air channel (5) through the No. 1 pulverized coal pipeline (27), and the No. 3 regulating valve (26) is connected in series to the No. 1 pulverized coal pipeline (27).

4. The high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 3, characterized in that: The air supply pipeline comprises a DC secondary air channel (7), a secondary air channel (32) and a No. 4 regulating valve (34); one end of the DC secondary air channel (7) is connected to the corresponding DC secondary air nozzle (3); one end of the secondary air channel (32) is connected to the air outlet end of the corresponding secondary air box (31); the other end of the DC secondary air channel (7) is connected to the other end of the secondary air channel (32); and the No. 4 regulating valve (34) is installed at the connection between the DC secondary air channel (7) and the secondary air channel (32).

5. The high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 4, characterized in that: The self-help combustion stabilizing burner (2) comprises a combustion stabilizing chamber (4), a secondary air channel (6) in a swirl flow, and a DC primary air channel (8) of the self-help combustion stabilizing burner. The secondary air channel (6) in a swirl flow is coaxially sleeved outside the DC primary air channel (8) of the self-help combustion stabilizing burner, and one end of the DC primary air channel (8) of the self-help combustion stabilizing burner and one end of the secondary air channel (6) in a swirl flow are both connected to the combustion stabilizing chamber (4), and the other end of the DC primary air channel (8) of the self-help combustion stabilizing burner is connected to a coal supply pipeline through an air powder system, and the other end of the secondary air channel (6) in a swirl flow is connected to a coal supply pipeline through an air powder system. The air duct is connected, an axial blade group (9) is provided between the DC primary air channel (8) of the self-service combustion stabilizing burner and the secondary air channel (6) in the swirl, and the axial blade group (9) is arranged close to the combustion stabilizing chamber (4), the axial blade group (9) includes a plurality of axial blades, and the plurality of axial blades are arranged equidistantly along the circumferential direction between the DC primary air channel (8) of the self-service combustion stabilizing burner and the secondary air channel (6) in the swirl, and one end of each axial blade is connected to the outer wall of the DC primary air channel (8) of the self-service combustion stabilizing burner, and the other end of each axial blade is connected to the inner wall of the secondary air channel (6) in the swirl.

6. The high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 5, characterized in that: The air-powder system comprises a DC coal supply pipeline and a swirl air supply pipeline, wherein the coal supply pipeline is connected to a DC primary air channel (8) of a self-help stable combustion burner through the DC coal supply pipeline, and the air supply pipeline is connected to a secondary air channel (6) in the swirl through the swirl air supply pipeline; The DC coal supply pipeline comprises a DC connecting air duct of a self-help combustion stabilizing burner, a No. 5 regulating valve (24), a No. 2 coal powder channel (29) and a No. 6 regulating valve (30); the primary air duct (22) is connected to the DC primary air channel (8) of the self-help combustion stabilizing burner through the DC connecting air duct of the self-help combustion stabilizing burner, and the No. 5 regulating valve (24) is connected in series to the DC connecting air duct of the self-help combustion stabilizing burner; the No. 2 coal outlet of the coal powder separation device (28) is connected to the DC primary air channel (8) of the self-help combustion stabilizing burner through the No. 2 coal powder channel (29), and the No. 6 regulating valve (30) is connected in series to the No. 2 coal powder channel (29); The swirl air supply pipeline comprises a swirl connecting air duct of a self-service stabilizing combustion burner and a No. 7 regulating valve (33); the secondary air duct (32) is connected to the secondary air channel (6) in the swirl through the swirl connecting air duct of the self-service stabilizing combustion burner; the No. 7 regulating valve (33) is connected in series at the connection point between the secondary air channel (6) in the swirl and the connecting air duct of the self-service stabilizing combustion burner.

7. The high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 6, characterized in that: The air supply system comprises an air supply fan (14), a primary air fan (15), a secondary air duct (16), an air preheater (17), a cold primary air main duct (35), a hot primary air main duct (36) and a hot secondary air duct (37). The air preheater (17) is installed at the end of the furnace (18). The air outlet of the air supply fan (14) is connected to the first air inlet of the air preheater (17) through a pipeline. The air outlet of the primary air fan (15) is connected to the second air inlet of the air preheater (17) through a pipeline. The air inlet of the cold primary air main duct (35) is connected to the connecting duct between the primary air fan (15) and the air preheater (17). A plurality of primary air sub-tubes are arranged on the air outlet end of the pipe (35); an air inlet end of each primary air sub-tube is connected to the air outlet end of the cold primary air main pipe (35); the air outlet end of each cold primary air sub-tube is connected to the air inlet end of a coal mill (21); the air inlet end of the hot primary air main pipe (36) is connected to the No. 1 air outlet end of the air preheater (17); the air outlet end of the hot primary air main pipe (36) is connected to the air outlet end of the cold primary air main pipe (35); the air inlet end of the hot secondary air pipe (37) is connected to the No. 2 air outlet end of the air preheater (17); and the air outlet end of the hot secondary air pipe (37) is connected to the air inlet end of the secondary air box (31); A coal mill cold air regulating valve (56) is connected in series to the cold primary air main pipe (35); A coal mill hot air regulating valve (57) is connected in series to the hot primary air main pipe (36); A shut-off valve (58) is connected in series on the primary air pipe.

8. The high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 7, characterized in that: The air temperature supply air system (63) comprises a hot primary air supply air main pipe (38), a cold primary air supply air main pipe (39), a No. 1 cold primary air supply air duct (40), a No. 2 cold primary air supply air duct (41), a No. 1 hot primary air supply air duct (42) and a No. 2 hot primary air supply air duct (43). The air inlet end of the hot primary air supply air main pipe (38) is connected to the hot primary air main pipe (36). The No. 1 air outlet end of the hot primary air supply air main pipe (38) is connected to the DC primary air channel (5) through the No. 1 hot primary air supply air duct (42). The second air outlet end of the (38) is connected to the DC primary air channel (8) of the self-sustaining combustion burner through the second hot primary air supply pipe (43), the air inlet end of the cold primary air supply main pipe (39) is connected to the cold primary air supply main pipe (35), the first air outlet end of the cold primary air supply main pipe (39) is connected to the first hot primary air supply pipe (42) through the first cold primary air supply pipe (40), and the second air outlet end of the cold primary air supply main pipe (39) is connected to the second hot primary air supply pipe (43) through the second cold primary air supply pipe (41); A hot primary air regulating valve (44) is connected in series to the hot primary air supply main pipe (38); A cold primary air regulating valve (45) is connected in series to the cold primary air supply air main pipe (39); A first cold primary air supply air regulating door (46) is connected in series to the first cold primary air supply air duct (40); A second cold primary air make-up air duct (41) is connected in series with a second cold primary air make-up air regulating valve (47); A first hot primary air make-up air duct (42) is successively connected in series with a second shut-off valve (59), a first make-up air regulating valve (61), a first air velocity measuring device (49), and a first temperature measuring device (48) along the gas direction. Moreover, the second shut-off valve (59), the first make-up air regulating valve (61), the first air velocity measuring device (49), and the first temperature measuring device (48) are all located between the first cold primary air make-up air duct (40) and the direct current primary air passage (5); A second hot primary air make-up air duct (43) is successively connected in series with a third shut-off valve (60), a second make-up air regulating valve (62), a second temperature measuring device (50), and a purging valve (51) along the gas direction. Moreover, the third shut-off valve (60), the second make-up air regulating valve (62), the second temperature measuring device (50), and the purging valve (51) are all located between the second cold primary air make-up air duct (41) and the direct current primary air passage (8) of the self-stabilizing combustion burner; The air temperature make-up air system (63) further includes a heat exchanger (53). The heat exchanger (53) is connected in series on the direct current primary air passage (8) of the self-stabilizing combustion burner. The heat exchange air inlet end of the heat exchanger (53) is communicated with the second hot primary air make-up air duct (43) through an induced air duct. The induced air duct is located between the second temperature measuring device (50) and the purging valve (51). A heat exchange valve (66) is connected in series on the induced air duct. The heat exchange air return end of the heat exchanger (53) is communicated with the hot primary air main pipe (36) through a heat exchanger return pipe (65); 9. The high-efficiency direct current burner and swirl burner cooperative combustion device according to claim 8, characterized in that: A heater (64) is also connected in series on the hot primary air make-up air main pipe (38); 10. A coordinated combustion method using a high-efficiency direct current burner and a swirl burner coordinated combustion device according to any one of claims 1 to 9 when the boiler is operating at a load condition lower than 15% of the rated load, characterized in that: The specific operation of the co-combustion method is as follows: Close the first regulating valve (23) and the fifth regulating valve (24), open the second regulating valve (25). The pulverized coal air flow controls the primary air velocity entering the direct current primary air passage (5) to u2 = 16 - 18 m / s by changing the opening degree of the third regulating valve (26). By adjusting the hot primary air regulating valve (44) and the cold primary air regulating valve (45), while basically not changing the original operation mode of the coal mill, high-temperature and high-pressure hot primary air is provided to the air temperature make-up air system (63). Open the second shut-off valve (59). By adjusting the opening degrees of the first make-up air regulating valve (61) and the first cold primary air make-up air regulating valve (46), control the hot primary air volume and air temperature supplemented into the direct current primary air passage. Among them, the make-up air velocity u1 is 30 - 32 m / s, the make-up air temperature T1 is 280 - 300 °C. After supplementation, it converges into the direct current primary air passage (5). At this time, the direct current primary air velocity u2 is increased to 24 - 27 m / s, and the air-powder flow temperature is increased from T3 = 50 - 90 °C to T3 = 180 - 210 °C. Through the above operations, by increasing the direct current primary air velocity, a large-scale central recirculation zone is formed in the stable combustion cavity (4) and the furnace. The diameter D of the recirculation zone is 2De < D < 2.5De, and the length L is 4De < L < 4.5De; By adjusting the hot primary air regulating valve (44) and the cold primary air regulating valve (45), it is ensured that the hot primary air with high temperature and high pressure is provided to the air temperature supply air system (63) without changing the original operation mode of the coal mill. The No. 3 shut-off valve (60) is opened. By adjusting the opening of the No. 2 supply air regulating valve (62) and the No. 2 cold primary air supply air regulating valve (47), the air temperature entering the No. 2 hot primary air supply air duct (43) is controlled. The supply air temperature T2 is 280-300°C. The purge valve (51) is closed and the heat exchange valve (66) is opened to achieve self-stable combustion. The temperature of the primary air-powder mixture in the DC primary air channel (8) of the burner is increased, and the supplementary air after heat exchange flows back to the primary air main pipe (36) through the heat exchanger return pipe (65), and the air-powder air flow temperature is increased from T3 = 50-90°C to T3 = 180-210°C. After the above operation, the air-powder air flow temperature in the DC primary air channel (5) and the self-service stabilizing burner DC primary air channel (8) is increased to 180-210°C, thereby achieving the purpose of increasing the primary air-powder temperature at the inlet of the DC burner and the self-service stabilizing burner when operating at less than 15% of the rated load.

Images