JP5678606B2 - Boiler equipment - Google Patents

Description

  The present invention relates to a boiler apparatus that performs high-temperature air combustion.

  There is a high-temperature air combustion type boiler apparatus (hereinafter referred to as a high-temperature air combustion boiler apparatus) in which high-temperature combustion air is supplied by an air nozzle separated from fuel and the fuel is injected into a furnace in a high-temperature state and burned. In the high-temperature air-fired boiler device, the furnace can be heated to a high temperature, so that the furnace can be downsized, and combustion can be performed in a reducing atmosphere with a low oxygen concentration. There is an advantage that you can.

  On the other hand, since the high temperature air combustion boiler apparatus has a short history, it is desired that the operation from the start of the boiler to the high temperature air combustion be performed more smoothly.

  In addition, as a boiler apparatus which carries out high temperature air combustion, there exists what is shown by patent document 1, and in the boiler apparatus shown by patent document 1, a high temperature air nozzle, a fuel nozzle, and a secondary air nozzle are separately provided from the lower side in the up-down direction. The pulverized coal is ejected from the fuel nozzle, the high-temperature air is injected from the high-temperature air nozzle toward the pulverized coal flow, and the pulverized coal is ignited and combusted, and 2 from the secondary air nozzle above the flame. Next air is ejected and unburned fuel is burned.

JP 2005-265298 A

  In view of such circumstances, the present invention provides a boiler device for high-temperature air combustion that can smoothly perform operations from boiler startup to high-temperature air combustion.

  The present invention includes a pulverized coal burner having an auxiliary combustion burner on a furnace wall of a boiler furnace, an air nozzle that is alternately arranged with the pulverized coal burner and ejects high-temperature combustion air, and a combustion state of the auxiliary combustion burner. A control device that controls the combustion state of the pulverized coal burner and the air ejection state of the air nozzle, and the control device stops the air nozzle when the boiler furnace is at a low temperature, and burns by the auxiliary combustion burner In a state where the boiler furnace temperature is raised to the first set value and the air nozzle is stopped, the auxiliary combustion burner is shifted to pulverized coal combustion by the pulverized coal burner, and the boiler furnace temperature is set to the second temperature. In a state where the set value has been reached, combustion air to the pulverized coal burner is stopped, pulverized coal is ejected from the pulverized coal burner, hot air is ejected from the air nozzle, and high-temperature air combustion is performed. Those of the boiler apparatus to.

  The present invention also relates to a boiler device that interposes the mixed combustion state of the auxiliary combustion burner and the pulverized coal burner in a process in which the control device shifts from combustion by the auxiliary combustion burner to combustion by the pulverized coal burner. is there.

  Further, the present invention relates to a boiler device in which the control device interposes the mixed combustion state at least before or after the high-temperature air combustion is realized.

  Further, in the present invention, when the boiler furnace temperature falls below the second set value, the control device stops jetting of high-temperature air from the air nozzle, and supplies combustion air to the pulverized coal burner, The present invention relates to a boiler device that shifts to combustion by a pulverized coal burner.

  Further, according to the present invention, when the boiler furnace temperature falls below the second set value, the control device stops jetting of high-temperature air from the air nozzle and supplies pulverized coal to the pulverized coal burner. The present invention relates to a boiler device that stops and supplies combustion air to the pulverized coal burner and shifts to combustion by an auxiliary combustion burner.

  The present invention also relates to a boiler apparatus provided with an exhaust gas conduit for connecting a duct for supplying high temperature air to the air nozzle and a boiler flue, and the extracted exhaust gas is mixed with the high temperature air.

  According to the present invention, a pulverized coal burner having an auxiliary combustion burner on the furnace wall of a boiler furnace, an air nozzle that is alternately arranged with the pulverized coal burner and ejects high-temperature combustion air, and combustion of the auxiliary combustion burner And a control device for controlling the combustion state of the pulverized coal burner and the air ejection state of the air nozzle. The control device stops the air nozzle when the boiler furnace is at a low temperature, and the auxiliary combustion burner. When the boiler furnace temperature is raised to the first set value and the air nozzle is stopped, the auxiliary combustion burner is shifted to pulverized coal combustion with the pulverized coal burner, and the boiler furnace temperature is In a state where the second set value has been reached, combustion air to the pulverized coal burner is stopped, pulverized coal is ejected from the pulverized coal burner, hot air is ejected from the air nozzle, Because to realize, smoothly from the boiler start up to the high temperature air combustion, also exhibits an excellent effect of reliably migrated.

It is a schematic block diagram which shows the boiler apparatus which concerns on the Example of this invention. It is explanatory drawing which shows an example of arrangement | positioning of the pulverized coal burner and combustion air nozzle which are used for this boiler apparatus. It is a schematic sectional drawing which shows an example of the pulverized coal burner used for this boiler apparatus. It is a timing chart which shows the aspect of the 1st combustion of a present Example. It is a timing chart which shows the aspect of the 2nd combustion of a present Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, referring to FIG. 1 and FIG. 2, an outline of the boiler apparatus according to the present embodiment will be described.

  In FIG. 1, 1 is a furnace, 2 is a heat exchanger using the residual heat of exhaust gas as a heat source, 3 is a pulverized coal mill, 4 is a required number of pulverized coal burners provided on the furnace wall, and 5 is provided on the furnace wall 6 is a primary air blower for sending primary air, 7 is a secondary air blower for sending secondary air, 8 is an exhaust gas blower for discharging exhaust gas, and 23 is a control device. . The pulverized coal burners 4 and the combustion air nozzles 5 are alternately arranged at a predetermined pitch in the horizontal direction. Further, the pulverized coal burner 4 and the combustion air nozzle 5 are arranged in a plurality of stages (two stages are illustrated in the drawing), and the pulverized coal burner 4 and the combustion air nozzle 5 are arranged adjacent to each other in the up and down direction. It has become. That is, the pulverized coal burner 4 and the combustion air nozzle 5 are alternately arranged in the horizontal direction and the vertical direction, respectively.

  Note that the pulverized coal burners 4 and the combustion air nozzles 5 arranged alternately may be one stage.

  The primary air blower 6 is connected to the heat exchanger 2 through a primary air blow duct 11, and the primary air blow duct 11 is heated to a predetermined temperature, for example, 200 ° C. by the heat exchanger 2. The primary air is guided to the pulverized coal mill 3. The pulverized coal mill 3 pulverizes massive coal into pulverized coal, uses primary air as a carrier medium, and individually feeds the pulverized coal mixed flow to the pulverized coal burner 4 through the pulverized coal supply pipe 12. Each pulverized coal supply pipe 12 is provided with a cut damper 13, and the cut damper 13 can individually block and open the pulverized coal supply pipe 12. The supply of pulverized coal can be stopped independently.

  Further, the upstream side and the downstream side of the heat exchanger 2 of the primary air blowing duct 11 are connected by a primary air bypass duct 9 so that low-temperature air before heating is mixed with primary air after heating. It is supposed to be done. The primary air bypass duct 9 is provided with a flow rate adjusting valve 10, the amount of low-temperature air mixed is adjusted by the flow rate adjusting valve 10, and the temperature of the primary air supplied to the pulverized coal mill 3 is adjusted. It is like.

  A secondary air blowing duct 14 is connected to the heat exchanger 2, and the secondary air blowing duct 14 is individually connected to the heat exchanger 2, the pulverized coal burner 4, and the combustion air nozzle 5, The secondary air blowing duct 14 a connected to the pulverized coal burner 4 is provided with a first flow rate adjusting damper 17, and the secondary air blowing duct 14 b connected to the combustion air nozzle 5 is provided with a second flow rate adjusting damper 18. Is provided.

  The secondary air sent out from the secondary air blower 7 is heated by the heat exchanger 2 through the secondary air blow duct 14 as combustion air, and further, the secondary air blow duct 14 and the secondary air. It is fed to the pulverized coal burner 4 through the air duct 14a.

  Similarly, the secondary air sent out from the secondary air blower 7 is heated as the combustion air in the heat exchanger 2 through the secondary air blower duct 14, and further, the secondary air blower duct 14, It is fed to the combustion air nozzle 5 through a secondary air blowing duct 14b.

  The flue 16 of the furnace 1 and the secondary air blowing duct 14 are connected by an exhaust gas conduit 15, and an exhaust gas flow rate regulator 20 is provided in the exhaust gas conduit 15. The exhaust gas conduit 15 extracts high-temperature exhaust gas before heat exchange from the flue 16 and mixes it with the secondary air after heat exchange. By mixing the hot exhaust gas with the secondary air, the temperature of the secondary air that is higher than that heated by the heat exchanger 2 can be obtained.

  The exhaust gas flow rate regulator 20 has a flow rate adjusting function and an opening / closing function, and is opened when high-temperature air combustion described later is performed. The high-temperature exhaust gas is mixed with the secondary air, It is supplied to the combustion air nozzle 5 as combustion air for high-temperature air combustion.

  Here, the secondary air temperature before the exhaust gas is mixed is 250 ° C. to 300 ° C., and the secondary air temperature after mixing for high temperature air combustion is 550 ° C. to 1350 ° C. In view of the stability of high-temperature air combustion, thermal efficiency, etc., the temperature is preferably 750 ° C. to 850 ° C., for example, about 800 ° C.

  The first flow rate adjusting damper 17 adjusts the flow rate of the secondary air supplied to the pulverized coal burner 4 or cuts off the supply of the secondary air. The second flow rate adjusting damper 18 stops the supply of high-temperature combustion secondary air to the combustion air nozzle 5 and further adjusts the flow rate. The first flow rate adjustment damper 17 and the second flow rate adjustment damper 18 are alternatively opened and closed. When the first flow rate adjustment damper 17 is opened, the second flow rate adjustment damper 18 is fully When the second flow rate adjustment damper 18 is closed and the second flow rate adjustment damper 18 is opened, the first flow rate adjustment damper 17 is fully closed.

  The pulverized coal burner 4 has an air volume adjusting blade (described later) for giving a swirling flow to the secondary air. By adjusting the angle of the air volume adjusting blade, the turning force is adjusted and the secondary air is adjusted. Adjust the air flow rate. Further, the supply of secondary air can be blocked by bringing the air volume adjusting blades into close contact with each other.

  The pulverized coal burner 4 has an auxiliary combustion burner (described later). The auxiliary combustion burner uses oil or gas as fuel, and is capable of self-combustion at a low temperature (for example, room temperature). A fuel supply pipe 19 is connected to the auxiliary combustion burner, and the auxiliary combustion burner is connected to a fuel supply source (not shown) via the fuel supply pipe 19. The fuel supply pipe 19 is provided with an oil flow rate adjusting valve 21, the amount of fuel supplied is adjusted by the oil flow rate adjusting valve 21, and the fuel supply is stopped.

  The flue 16 is provided with a temperature detector 22 for detecting the exhaust gas temperature, and the detection result of the temperature detector 22 is input to the control device 23. Further, the control device 23 receives a combustion control command for performing a comprehensive control of the boiler device body and requesting a combustion state corresponding to the boiler load state from the main control device.

  The control device 23 is based on the temperature detection signal from the temperature detector 22 and a combustion control command, and the pulverized coal mill 3, the flow rate adjustment valve 10, the cut damper 13, the first flow rate adjustment damper 17, The second flow rate adjusting damper 18, the exhaust gas flow rate adjuster 20, and the oil flow rate adjusting valve 21 are driven and opened / closed at required timings, the combustion state of the pulverized coal burner 4, and the hot air from the combustion air nozzle 5 To control the eruption.

  FIG. 3 shows an example of the pulverized coal burner 4 used in this embodiment. The outline of the pulverized coal burner 4 will be described below with reference to FIG.

  A throat 25 is provided on the furnace wall 24 of the furnace 1, a wind box 26 is attached to the counter-fire furnace side of the furnace wall 24, and a pulverized coal burner 4 is provided concentrically with the throat 25 inside the wind box 26. Yes.

  The pulverized coal burner 4 includes a nozzle main body 27 and a secondary air adjusting device 28 provided so as to surround the tip of the nozzle main body 27.

  The nozzle body 27 includes an inner cylinder nozzle 29 provided concentrically with the nozzle body 27, and an oil burner 31 disposed on the center line of the inner cylinder nozzle 29. A fuel conduction space 32 is formed between the nozzle body 27 and the inner cylinder nozzle 29 in a hollow cylindrical space with the furnace 1 side end opened.

  The pulverized coal supply pipe 12 communicates with the base of the nozzle body 27 (the end on the side of the reaction furnace 1), and the pulverized coal mixed flow 33 is tangent to the fuel conduction space 32 via the pulverized coal supply pipe 12. It flows in from the direction, flows toward the tip while turning inside the fuel conduction space 32, and is ejected from the tip.

  The secondary air blowing duct 14 communicates with the window box 26, and combustion air flows as secondary combustion air 34 through the secondary air blowing duct 14. Further, a tertiary air introduction pipe 35 that opens to the inside of the window box 26 communicates with the base of the inner cylinder nozzle 29 to take in combustion air supplied to the window box 26 and to assist combustion air, that is, It is led to the inner cylinder nozzle 29 as tertiary combustion air 36.

  The secondary air conditioner 28 includes a secondary air guide duct 37 whose entire circumference is open to the inside of the wind box 26 and has a diameter reduced toward the tip, and a base portion of the secondary air guide duct 37. The air volume adjusting blades 38 are rotatable about a horizontal rotating shaft 39, and all the air volume adjusting blades 38 are synchronously driven by a rotation drive mechanism 41. It is supposed to be done. The secondary air guide duct 37 functions as a secondary air ejection nozzle.

  By maintaining the air volume adjusting blade 38 at a required angle by the rotation drive mechanism 41, a swirling flow is given to the secondary combustion air 34, and the swirling strength is adjusted by the angle of the air volume adjusting blade 38, If the adjacent air volume adjusting blades 38 are brought into close contact with each other, the opening of the base portion of the secondary air guide duct 37 can be fully closed. The tip of the secondary air guide duct 37 is continuous with the throat 25.

  Briefly describing the combustion in the pulverized coal burner, oil is supplied to the oil burner 31 as fuel, the oil is sprayed and ignited, and auxiliary combustion is performed. Auxiliary combustion is continued until the inside of the furnace rises to a predetermined temperature (a preset temperature), the inside of the furnace reaches the predetermined temperature, and the secondary combustion air 34 becomes a temperature sufficient to cause the pulverized coal to self-combust. In this state, a pulverized coal mixed stream 33 is supplied from the pulverized coal supply pipe 12.

  The pulverized coal mixed flow 33 flows while swirling in the fuel conduction space 32, is compressed in the process of passing through the fuel conduction space 32, and is ejected from the tip of the nozzle body 27. Further, the secondary combustion air 34 is fed from the window box 26 to the secondary air adjusting device 28, and the secondary combustion air 34 is swirled by the air volume adjusting blade 38, and the air volume is further adjusted. Then, it is ejected from the throat 25 to the furnace 1 through the secondary air guide duct 37.

  When the mixed combustion state of the auxiliary combustion by the oil burner 31 and the pulverized coal combustion by the pulverized coal burner 4 is continued, and the pulverized coal combustion by the pulverized coal burner 4 becomes a state in which self-combustion (steady combustion) is possible, the oil burner The auxiliary combustion by 31 is stopped, and it shifts to the steady combustion by the pulverized coal burner 4.

  Next, the operation of the boiler device according to this embodiment will be described with reference to FIG. FIG. 4 shows a first mode of high-temperature air combustion, and in the following description, the time lag due to responsiveness is ignored.

  When the temperature in the furnace is low at the start of the boiler (for example, room temperature Ta), the control unit 23 opens the oil flow rate adjusting valve 21 to start the supply of oil and adjust the supply amount. The first flow rate adjusting damper 17 is opened, secondary air is supplied to the pulverized coal burner 4, and auxiliary combustion is performed by an oil burner 31 provided in the pulverized coal burner 4. In the state where auxiliary combustion is performed by the oil burner 31, the second flow rate adjustment damper 18 and the exhaust gas flow rate regulator 20 are closed, and the cut damper 13 is also closed.

  The temperature in the furnace rises due to combustion by the oil burner 31, and the temperature detected by the temperature detector 22 is set to a first preset temperature, for example, 500 ° C., or the load factor of the boiler is, for example, 30%. The pulverized coal mill 3 is started, the cut damper 13 is opened, pulverized coal is supplied to the pulverized coal burner 4, and pulverized coal combustion by the pulverized coal burner 4 is started. In addition, even if the pulverized coal combustion by the pulverized coal burner 4 is started, the combustion by the oil burner 31 is continued, and mixed combustion by the oil burner 31 and the pulverized coal burner 4 is performed. The first set temperature and the load factor of the boiler are appropriately set depending on the capacity of the boiler, the operation state, etc., and are not limited to 500 ° C. or 30%.

  Further, when the temperature in the furnace rises and the temperature detected by the temperature detector 22 reaches a preset second set temperature, for example, 800 ° C., or the load factor of the boiler reaches, for example, 75%, the oil Combustion by the burner 31 is stopped. As the combustion by the oil burner 31 is stopped, the oil flow rate adjustment valve 21 is closed. The closed state of the second flow rate adjustment damper 18 and the exhaust gas flow rate regulator 20 is continued. In the mixed combustion state, a mixed combustion time may be set in advance, and combustion of the oil burner 31 may be stopped when the set mixed combustion time ends. Further, the second set temperature and the boiler load factor are appropriately set according to the capacity of the boiler, the operating state, etc., and are not limited to 800 ° C. or 75%.

  Here, steady combustion is performed by the pulverized coal burner 4. When the combustion mode of the boiler may be steady combustion of the pulverized coal burner 4, or when the required load factor of the boiler is low, the steady combustion of the pulverized coal burner 4 is continued.

  Further, when shifting to high-temperature air combustion, when the exhaust temperature detected by the temperature detector 22 becomes the temperature T1 (second set temperature) at which shifting to high-temperature air combustion, the first flow rate adjustment damper 17 is The secondary air supply is stopped. By stopping the supply of secondary air, pulverized coal combustion of the pulverized coal burner 4 is stopped, but the pulverized coal is continuously injected.

  The exhaust gas flow controller 20 is opened, high temperature exhaust gas is mixed with the secondary air, and the temperature of the secondary air is adjusted to a temperature required for high temperature air combustion. The second flow rate adjustment damper 18 is opened, and hot air is ejected from the combustion air nozzle 5. The pulverized coal ejected from the pulverized coal burner 4 is mixed in contact with the high-temperature air ejected from the adjacent combustion air nozzle 5 and burned.

Therefore, the combustion state of the pulverized coal becomes a gentle combustion without a peak of the combustion temperature, and becomes a combustion in an environment having a low oxygen concentration, and the generation of nitrogen oxides (NO _x ) can be suppressed. When the hot air combustion reaches a steady state, the load factor is 100% or substantially 100%, and the exhaust temperature at this time is Tb.

  When the load of the boiler is reduced and the exhaust gas temperature is lower than the temperature T1, the second flow rate adjustment damper 18 is closed, the ejection of high-temperature air from the combustion air nozzle 5 is stopped, and the first The flow rate adjusting damper 17 is opened, secondary air having a low temperature is supplied to the pulverized coal burner 4 as combustion air, and pulverized coal steady combustion by the pulverized coal burner 4 is performed.

  When the exhaust gas temperature exceeds the temperature T1 again, the first flow rate adjustment damper 17 is closed, the second flow rate adjustment damper 18 and the exhaust gas flow rate regulator 20 are opened, and the pulverized coal burner 4 is opened. , Pulverized coal is ejected from the combustion air nozzle 5, and high-temperature combustion air is ejected from the combustion air nozzle 5.

  That is, the pulverized coal steady combustion and the high-temperature air combustion are switched by switching the opening and closing of the first flow rate adjustment damper 17, the second flow rate adjustment damper 18, and the exhaust gas flow rate regulator 20.

  Actually, even if the load decreases, the furnace temperature does not decrease sensitively. Therefore, when shifting to high-temperature air combustion, high-temperature air combustion continues even when the load fluctuates.

  Next, the operation of the boiler apparatus according to this embodiment will be described with reference to FIG. FIG. 5 shows a second mode of high-temperature air combustion, and in the following description, the time lag due to responsiveness is ignored.

  When the boiler is started, the pulverized coal mill 3 is in a stopped state, the cut damper 13 is closed, the second flow rate adjusting damper 18 and the exhaust gas flow rate regulator 20 are closed, and the control device 23 controls the oil flow rate. The adjustment valve 21 is opened, and the supply of oil is started and the supply amount is adjusted. The first flow rate adjusting damper 17 is opened, secondary air is supplied to the pulverized coal burner 4, and combustion is performed by the oil burner 31 provided in the pulverized coal burner 4.

  When the temperature in the furnace rises due to combustion by the oil burner 31 and the temperature of the exhaust gas detected by the temperature detector 22 reaches the temperature T1, the first flow rate adjustment damper 17 is closed, and the pulverized coal burner 4 The secondary air supply to the engine is stopped, the exhaust gas flow rate regulator 20 and the second flow rate adjustment damper 18 are opened, and high temperature secondary air mixed with the exhaust gas is supplied to the combustion air nozzle 5.

  By stopping the supply of secondary air to the pulverized coal burner 4, combustion of the oil burner 31 is stopped, and only oil is injected from the oil burner 31 into the furnace. Further, high-temperature combustion air is jetted from the adjacent combustion air nozzles 5, and high-temperature air combustion using oil and high-temperature air is performed.

  When a predetermined time elapses after the oil enters a high-temperature air combustion state, the pulverized coal mill 3 is operated, the cut damper 13 is opened, pulverized coal is supplied to the pulverized coal burner 4, and the pulverized coal burner 4 As the oil is ejected, pulverized coal is ejected, resulting in high-temperature air combustion in a mixed combustion state of oil and pulverized coal. When the co-firing state has passed a preset time, the oil flow rate adjusting valve 21 is closed and the pulverized coal burner 4 shifts to high-temperature air combustion only by pulverized coal combustion.

After realizing high-temperature air combustion by oil combustion by the oil burner 31, when shifting to pulverized coal combustion by the pulverized coal burner 4, high-temperature air combustion is reached in a short time and until the high-temperature air combustion is reached, the sulfur content Because it is an oil combustion with a small amount of oil and shifts to a pulverized coal combustion in a high-temperature air combustion state, the pulverized coal combustion becomes a high-temperature combustion from the beginning and burns in a reducing atmosphere, maximizing the generation of nitrogen oxides (NO _x ). Can be suppressed. That is, by realizing high temperature air combustion by oil combustion by the oil burner 31, nitrogen oxides generated from the start of the boiler to the high temperature air combustion can be greatly reduced.

  When information on a decrease in the operating load of the boiler is input from the control device of the boiler device to the control device 23, the oil flow rate adjustment valve 21 is opened and oil combustion by the oil burner 31 is performed. In a state where high-temperature air combustion is maintained by oil combustion of the oil burner 31, the cut damper 13 is closed, supply of pulverized coal to the pulverized coal burner 4 is stopped, and oil combustion of the oil burner 31 alone Hot air combustion at is maintained. In this state, when the boiler load further decreases and the exhaust gas temperature becomes lower than the temperature T1, the first flow rate adjustment damper 17 is opened, and the second flow rate adjustment damper 18 and the exhaust gas flow rate regulator 20 are closed. Then, the supply of high-temperature air to the combustion air nozzle 5 is stopped, and the routine shifts to a steady combustion operation by the oil burner 31.

  Even when the load decreases and the high temperature air combustion shifts to the steady combustion, the pulverized coal combustion in the pulverized coal burner 4 is stopped while the high temperature air combustion is maintained. Combustion occurs only in the combustion state, and the generation of nitrogen oxides can be suppressed.

  Next, when the boiler load rises and the exhaust gas temperature exceeds T1, the first flow rate adjustment damper 17 is closed, the second flow rate adjustment damper 18 and the exhaust gas flow rate regulator 20 are opened, and high-temperature air is discharged. It is supplied to the combustion air nozzle 5. In this case, as described above, after the high-temperature air combustion is realized by the oil combustion by the oil burner 31, the pulverized coal combustion by the pulverized coal burner 4 may be started. The case where high temperature air combustion is maintained by oil combustion alone is shown.

  In the present embodiment, it is possible to appropriately select whether to maintain high-temperature air combustion by pulverized coal combustion or oil combustion. In the above embodiment, the fuel of the auxiliary burner has been described as oil, but the fuel may be gas.

DESCRIPTION OF SYMBOLS 1 Furnace 2 Heat exchanger 3 Pulverized coal mill 4 Pulverized coal burner 5 Combustion air nozzle 9 Primary air bypass duct 11 Primary air ventilation duct 12 Pulverized coal supply pipe 13 Cut damper 14 Secondary air ventilation duct 15 Exhaust gas conduit 17 1st Flow rate adjusting damper 18 Second flow rate adjusting damper 19 Fuel supply pipe 20 Exhaust gas flow rate regulator 21 Oil flow rate regulating valve 22 Temperature detector 23 Controller 27 Nozzle body 29 Inner cylinder nozzle 31 Oil burner 33 Pulverized coal mixed flow 34 For secondary combustion Air 36 Air for tertiary combustion 38 Air volume adjusting blade 41 Rotation drive mechanism

Claims (8)

A nozzle body, a secondary air adjusting device provided so as to surround the tip of the nozzle body, an inner cylinder nozzle provided concentrically with the nozzle body, and a center line of the inner cylinder nozzle A pulverized coal burner which has an auxiliary combustion burner, ejects combustion air from the periphery of the nozzle body, and ejects pulverized coal from a fuel conduction space between the nozzle body and the inner cylinder nozzle, and a furnace of a boiler furnace An air nozzle that is alternately disposed on the wall with the pulverized coal burner and that ejects high-temperature combustion air; a combustion state of the auxiliary combustion burner; a combustion state of the pulverized coal burner; and an air ejection state of the air nozzle and a control device, the control device, the boiler furnace stops the air nozzle at a low temperature state, the pulverized coal burner performs combustion by the auxiliary combustion burner, boiler furnace temperature rises to a first predetermined value In a state, and a state where the air nozzle is stopped, the with the secondary air adjusting device for supplying combustion air ejected pulverized coal from the fuel flow space, burning the pulverized coal burner according to the auxiliary combustion burner from then proceeds to pulverized coal combustion, in a state in which the boiler furnace temperature reaches the second set value, the pulverized coal burner stops combustion air, is ejected pulverized coal from the fine coal burner, hot from the air nozzle A boiler apparatus characterized by jetting air and mixing and contacting high temperature air and pulverized coal inside the boiler furnace to realize high temperature air combustion.   2. The boiler apparatus according to claim 1, wherein the control device interposes a mixed combustion state of the auxiliary combustion burner and the pulverized coal burner in a process of shifting from combustion by the auxiliary combustion burner to combustion by the pulverized coal burner.   The boiler apparatus according to claim 2, wherein the control device interposes the mixed combustion state at least before or after the high-temperature air combustion is realized. Wherein the control device, when the boiler furnace temperature drops below the second set value, the stop ejection of hot air from the air nozzle, the combustion air supplied to the pulverized coal burner, according to the pulverized coal burner The boiler apparatus of Claim 1 which transfers to combustion. When the boiler furnace temperature falls below the second set value, the control device stops jetting of high-temperature air from the air nozzle, stops supplying pulverized coal to the pulverized coal burner, and supplying combustion air to the coal burners, boiler apparatus according to claim 1, the process proceeds to combustion by the auxiliary combustion burner.   6. The boiler according to claim 1, 4 or 5, wherein an exhaust gas conduit connecting a duct for supplying high temperature air to the air nozzle and a boiler flue is provided, and the extracted exhaust gas is mixed with the high temperature air. apparatus.   A pulverized coal burner having an auxiliary combustion burner on the furnace wall of a boiler furnace, an air nozzle that is alternately arranged with the pulverized coal burner and ejects high-temperature combustion air, a combustion state of the auxiliary combustion burner, and the pulverized coal burner A control device for controlling the combustion state of the air nozzle and the air ejection state of the air nozzle, the control device stops the air nozzle when the boiler furnace is in a low temperature state, performs combustion by the auxiliary combustion burner, With the furnace temperature raised to the first set value and the air nozzle stopped, the auxiliary combustion burner is shifted to pulverized coal combustion with the pulverized coal burner, and the boiler furnace temperature reaches the second set value. In this state, the combustion air to the pulverized coal burner is stopped, pulverized coal is ejected from the pulverized coal burner, hot air is ejected from the air nozzle, and high-temperature air combustion is realized. When the boiler furnace temperature falls below the second set value, the injection of high-temperature air from the air nozzle is stopped, the combustion air is supplied to the pulverized coal burner, and the process shifts to combustion by the pulverized coal burner. Boiler device characterized.   A pulverized coal burner having an auxiliary combustion burner on the furnace wall of a boiler furnace, an air nozzle that is alternately arranged with the pulverized coal burner and ejects high-temperature combustion air, a combustion state of the auxiliary combustion burner, and the pulverized coal burner A control device for controlling the combustion state of the air nozzle and the air ejection state of the air nozzle, the control device stops the air nozzle when the boiler furnace is in a low temperature state, performs combustion by the auxiliary combustion burner, With the furnace temperature raised to the first set value and the air nozzle stopped, the auxiliary combustion burner is shifted to pulverized coal combustion with the pulverized coal burner, and the boiler furnace temperature reaches the second set value. In this state, the combustion air to the pulverized coal burner is stopped, pulverized coal is ejected from the pulverized coal burner, hot air is ejected from the air nozzle, and high-temperature air combustion is realized. When the boiler furnace temperature falls below the second set value, the ejection of high-temperature air from the air nozzle is stopped, the supply of pulverized coal to the pulverized coal burner is stopped, and the combustion air to the pulverized coal burner , And the boiler device shifts to combustion by the auxiliary combustion burner.

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