JP5888726B2 - Solid fuel boiler system and solid fuel burner - Google Patents

Description

  The present invention relates to a boiler that burns solid fuel, particularly low-grade coal with a low fuel ratio such as peat, lignite, subbituminous coal, and the like, which can efficiently burn solid fuel that has a high water content and needs to be dried before combustion. The present invention relates to a solid fuel boiler system and a solid fuel burner mainly used in a thermal power plant.

  Brown coal is an inexpensive fuel with abundant resources, but its moisture content is very high at about 40 to 60% by weight, and it is not suitable for transportation as it is. Accordingly, various techniques for dehydrating and drying lignite have been developed, but they have not been widely used in terms of economy and the like. For this reason, lignite as a fuel for a boiler for a thermal power plant is often supplied directly to the boiler as a fuel without performing a dehydration / drying process in a plant near the coal-producing area. However, in this case, since much of the generated heat is consumed for the evaporation of moisture, it is inevitable that the final power generation efficiency is lowered.

In Patent Document 1 (Japanese Patent Application Laid-Open No. 59-97408), pulverized coal conveyed with an air amount less than the theoretical combustion air amount and coarse pulverized coal conveyed with an air amount greater than the theoretical combustion air amount are not mixed. Inject into the furnace from the same combustion burner to form fine powder flame and coarse powder flame from the fine powder combustion gas and coarse powder combustion gas, respectively, and thoroughly mix the fine powder combustion gas and coarse powder combustion gas in the furnace By reacting NH ₃ and HCN in the fine powder combustion gas with NOx in the coarse powder combustion gas, NOx is reduced to N _2, and unburned content in the fine powder combustion gas is reduced with excess oxygen in the coarse powder combustion gas. It is described that, by reacting, the generation of unburned coal in coal is reduced and the NOx concentration in exhaust gas can also be reduced.

  In Patent Document 2 (JP-A-1-217110), pulverized coal and pulverized coal are transported through a coal transport pipe connected to a burner nozzle, and pulverized coal is removed by a louver type coarse powder separator provided in the coal transport pipe. A configuration is disclosed in which pulverized coal is captured by a flame holder provided on the inner wall side of the outlet portion of the burner nozzle and provided at the outlet portion of the burner nozzle to promote ignition of the pulverized coal.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 5-237413) discloses a rotary classifier at the outlet of a mill when supplying pulverized coal pulverized in a coal pulverizing mill to a burner nozzle from the outlet of the mill. By adjusting the mounting angle of the fixed blades provided in the pulverized coal, it is possible to supply more than a certain amount of pulverized coal to the burner nozzle at a certain amount or more, so that the ignitability and flame holding performance of the coal at the burner nozzle outlet is maintained even at low load. A configuration that can be used is disclosed.

JP 59-97408 A JP-A-1-217110 JP-A-5-237413

  The invention described in the above patent document does not mention the combustibility of low-grade coal such as lignite. Brown coal has a large proportion of wood that is not carbonized, and fibrous wood remains in the pulverizer without being finely pulverized and consumes excessive pulverization power. For this reason, there is a problem that the efficiency as a thermal power plant is lowered.

  The subject of the present invention is a solid fuel boiler that uses high-moisture coal as fuel, such as peat and lignite, to reduce moisture in the fuel efficiently at low cost, and to suppress an increase in equipment costs and grinding power, To provide a solid fuel boiler system that contributes to improving the efficiency (power generation end efficiency) of a thermal power plant and a solid fuel burner that can be used in the system.

The above-mentioned problem of the present invention is solved by the following means.
The invention according to claim 1 is a solid fuel boiler (124) provided with a plurality of burner groups composed of two or more solid fuel burners (15, 15,...), And exhaust gas and combustion from the boiler (124). The solid fuel boiler system has a gas preheater (18) for exchanging heat between the working gas and the carrier gas, and each solid fuel burner (15) has coarse powder and fine powder of solid fuel in separate systems. A coarse powder supply system and a fine powder supply system for introducing and burning are connected, and the coarse powder supply system passes the solid fuel carrier gas through the gas preheater (18) to the solid fuel burner. The first high-temperature carrier gas pipe (105) for coarse powder introduced into (15) and the first high-temperature carrier gas pipe (105) for coarse powder branched from the upstream side of the gas preheater (18). First low-temperature carrier gas distribution for coarse powder (106) and branched from the first coarse powder high temperature carrier gas pipe (105) on the downstream side of the gas preheater (18) to the first coarse powder cold carrier gas pipe (106). The second coarse powder high-temperature carrier gas pipe (109) to be connected and the second coarse powder high-temperature carrier gas pipe (109) were connected to the first coarse powder low-temperature carrier gas pipe (106). A coarse powder mixer (5) for mixing coarse powder of solid fuel provided on the downstream side of the connecting portion, and a coarse powder mixer (5) for supplying coarse powder to the solid fuel burner (15) 3 and 4 high-temperature carrier gas pipes (107, 108) for coarse powder, and the fine powder supply system passes the solid fuel carrier gas to the solid fuel burner (15) via the gas preheater (18). First high-temperature carrier gas pipe (105 ′) for fine powder to be introduced and the upstream side of the gas preheater (18) The first fine powder low-temperature carrier gas pipe (106 ') branched from the first fine powder high-temperature carrier gas pipe (105') and the gas preheater (18) on the downstream side of the first fine powder A second fine powder high temperature carrier gas pipe (109 ') branched from the high temperature carrier gas pipe (105') and connected to the first fine powder low temperature carrier gas pipe (106 '); and the second fine powder The first high-temperature carrier gas pipe (106 ') on the downstream side of the connecting portion where the high-temperature carrier gas pipe (109') is connected to the first low-temperature carrier gas pipe (106 ') for fine powder. The solid fuel coarse powder connected to the carrier gas fan (23) and the first low-temperature carrier gas pipe (106 ′) for the fine powder on the downstream side of the carrier gas fan (23) is finely pulverized to pulverize the solid fuel. A fine pulverizer (24) for generating fine powder and supplying it to the carrier gas stream; And a solid fuel burner (15) Third fine powder for hot carrier gas pipe for supplying fines (107 ') from the coarse powder supply system, the coarse powder mixer (5) of the plurality of burners groups (15, 15,...) Are provided corresponding to each, and the fine powder supply system is configured such that the fine pulverizer (24) has a plurality of burner groups (15, 15,...). It is a solid fuel boiler system provided with at least one machine.

  The invention according to claim 2 is constructed between a set of drive shaft bodies (72, 73) arranged at a predetermined interval and the set of drive shaft bodies (72, 73), A fluidized bed of a transported object provided with a gas jetting part (79) that circulates around the drive shaft (72, 73) to receive and transport the transported object, and jets a drying gas at the bottom thereof. A conveyor device (39) provided with a forming conveying member (75) and provided with an air box (85) for supplying the drying gas from below the conveying member (75) into the conveying member (75). A plurality of coarse powder mixers (5) and pulverized coal machines (24) are provided as conveyor devices for reducing the water content of coarse powder obtained by coarsely pulverizing solid fuel. The solid fuel boiler system according to Item 1.

According to the third aspect of the present invention, the third and fourth high-temperature carrier gas pipes for coarse powder (107, 108) are connected via a hot-air mixer (13). And a fourth coarse powder high-temperature carrier gas pipe (108), and the hot air mixer (13) branches from the second coarse powder high-temperature carrier gas pipe (109) to the fifth coarse powder high-temperature carrier. 2. The solid fuel boiler system according to claim 1, wherein a gas pipe (112) is connected.

The invention according to claim 4 omits the installation of the fine powder supply system and separates the fine powder between the third high-temperature carrier gas pipe for coarse powder (107) and the hot air mixer (13) (41 ), And a fine powder conveying pipe (46) having a fine powder pressure adjusting damper (47) for conveying fine powder separated by the cyclone separator (41) directly to the solid fuel burner (15) is connected to the cyclone separator (41) and the solid fuel burner. The solid fuel boiler system according to claim 3, wherein the solid fuel boiler system is provided between (15).

According to a fifth aspect of the present invention, a hot air mixing damper (42) is provided in the fifth high-temperature carrier gas pipe (112) for coarse powder, and is connected to the fifth high-temperature carrier gas pipe (112) for coarse powder. The second coarse powder high-temperature carrier gas pipe (109) on the downstream side of the section is provided with a carrier air temperature adjustment damper (8), and connected to the second coarse powder high-temperature carrier gas pipe (109). A carrier air flow rate adjusting damper (7) is provided in the first coarse powder low-temperature carrier gas pipe (106) on the upstream side, and is connected to the second coarse powder high-temperature carrier gas pipe (109). The first coarse powder low temperature carrier gas pipe (106) on the flow side is provided with a carrier air flow meter (9) for measuring the flow rate of the carrier air, and the fifth coarser on the downstream side from the hot air mixing damper (42). Hot air flow rate in the fifth high-temperature carrier gas pipe (112) for coarse powder to the high-temperature carrier gas pipe (112) for powder Coarse powder mixing provided with a hot air flow meter (12) to measure and measuring the coarse powder mixer outlet temperature in the third high-temperature carrier gas pipe (107) for coarse powder on the outlet side of the coarse powder mixer (5) Provided with a burner inlet thermometer (11) for measuring the burner inlet temperature in the fourth high-temperature carrier gas pipe (108) for coarse powder, and the carrier air temperature adjusting damper (8). The opening degree is controlled based on the measured value of the coarse powder mixer outlet thermometer (11), and the opening degree of the hot air mixing damper (42) is set to a deviation value (119) between the coal supply command value and the minimum air flow rate. Based on the hot air flow rate command value (123) calculated based on this and the integrated value (120) of the measured value of the burner inlet thermometer (14), the opening degree of the conveying air flow rate adjustment damper (7) is (i) conveyed. Integrated value of the measured value of the hot air flow meter (12) and the measured value of the air flow meter (9) ( 16) and the command value (118) calculated from the first deviation signal (117) which is a deviation value between the coal supply command value (115) and (b) the measured value of the air flow meter (9) and the lowest based on the command signal value calculated by the second deviation signal which is a deviation of the air flow (119) (118), comprising a control mechanism for controlling such required air amount is obtained a minimum amount of air as the lower limit The solid fuel boiler system according to claim 1.

A sixth aspect of the present invention is a solid fuel burner used in the solid fuel boiler system according to the first aspect, wherein a mixture of coarse coal and primary air flows in a central portion, and the mixed flow is narrowed in an inner wall portion. A primary fuel nozzle (45) having a venturi (29) is provided, and a secondary fuel nozzle (49) through which a mixed flow of pulverized coal and primary air flows is provided on the outer periphery of the primary fuel nozzle (45), and the primary fuel Disposing the tip of the outlet of the secondary fuel nozzle (49) ahead of the tip of the outlet of the nozzle (45), providing a flame holder (35) on the outer periphery of the tip of the outlet of the secondary fuel nozzle (49), The secondary fuel nozzle (49) is provided with a secondary air nozzle (50) having a secondary vane (31) in the outer periphery thereof and a guide sleeve having an outlet portion that sequentially expands. 50) has a tertiary register on the outer periphery That is a solid fuel burner, characterized in that a tertiary air nozzle (51).

(Function)
In the present invention, coal (brown coal) is mainly coarsened to an average particle size of about 2 mm, dried, and supplied to the burner. At that time, in order to continue the combustion of the coal (brown coal), pulverized coal containing several tens of% of 40 μm particles is necessary, and an amount of pulverized coal necessary for continuing combustion is made by a pulverizer and supplied to the burner. Moreover, although the particle size of the coarse powder is large and falls to the bottom of the combustion furnace, the coal is placed and burned at the bottom of the furnace for heat recovery.

  In a lignite coal fired boiler that burns lignite, which is a high-moisture coal, in order to improve efficiency by reducing pulverization power, finely pulverized fine powder and coarsely pulverized coarse powder are guided to one burner and burned by different systems.

  In addition, the amount of high-temperature / low-temperature gas (pre-heated by air preheater (A / H)) in the lignite transport system is adjusted in order to improve the efficiency of lignite-rich lignite without causing spontaneous ignition. Then adjust the temperature separately for fine powder and coarse powder. Here, the mill exit temperature is set to 70 ° C. for fine powder, and the coarse powder is set to 150 ° C. in the mixer (introduction section to the fuel conveyance system) and 250 ° C. in front of the burner.

  In the following description, the case where air is used as the combustion gas and the carrier gas is described. However, the present invention is not limited to only air, but also a combustion exhaust gas of a boiler, an oxygen-rich gas, etc. good. The fuel type is not limited to lignite, but can be widely applied to solid fuels that have a lot of moisture and a large pulverization power.

In order to easily ignite lignite mainly composed of coarse powder coarsely pulverized to an average particle diameter of about 2 mm with a burner, it is necessary to mix about 20% of fine powder with a particle diameter of 40 μm or less.
In the present invention, a part of the coarse powder that has been easily pulverized compared to the state before the drying process is pulverized by a pulverized coal machine (mill) and transferred to the burner with a low-temperature carrier gas. By igniting, the safety against the spontaneous ignition of the fuel on the transport system and the ignitability of the fuel in the burner are ensured.

  In addition, the present invention minimizes equipment and processes for pulverizing coarse particles that require a fine pulverizer that requires a large amount of power, cost, and maintenance costs. The fuel is supplied to the same burner as the main fuel, and the carrier gas temperature is increased immediately before the supply to promote combustion and improve boiler efficiency.

  Usually, it is possible to make coarse particles into coarse powder at 1/2 to 1/10 of the power for finely pulverizing coarse particles (power of fine pulverizer), and if it can be burned efficiently, Power generation efficiency can be improved.

  The coal coarse powder homogenized by squeezing the mixture of coarse coal and primary air with the venturi 29 of the burner for solid fuel of the present invention is supplied to the tip of the burner 15. On the other hand, the mixed flow of fine powder and primary air is supplied to the secondary fuel nozzle 49 provided on the outer peripheral portion of the primary fuel nozzle 45, and the mixed flow of fine powder and primary air at the tip of the burner 15 immediately before the flame holding ring 35. The fine powder is rolled back by the flame holding ring 35 to form a stable flame, and the coarse powder inside the fine powder is steamed and burned, whereby the coarse powder is also gasified and easily burned.

The air supplied to the burner 15 is arranged outside the secondary fuel nozzle 49 and is divided into a secondary air flow 30 flowing in the secondary air nozzle 50 and a tertiary air flow 32 flowing in the tertiary air nozzle 51. The adjustment by the secondary vane 31 in the secondary air nozzle 50 and the tertiary register 33 arranged in the tertiary air nozzle 51 etc. adjust the flame holding property of the fuel in the furnace, the NOx concentration in the combustion exhaust gas, the oxygen distribution, etc. Adjustment is possible.
Since the tip of the burner 15 causes an increase in NOx concentration when air is supplied excessively in the initial stage of combustion, air is suppressed by the guide sleeve 34 from excessive supply of combustion.

  According to the first aspect of the present invention, in the lignite coal fired boiler that burns lignite that is high moisture coal, in order to improve efficiency by reducing pulverization power, finely pulverized fine powder and coarsely pulverized coarse powder are separated from each other. In order to improve the efficiency of lignite with a high volatility, there is no problem of spontaneous ignition and high efficiency, the hot / cold gas of the lignite transport system (preheating by the air preheater) It is possible to adjust the temperature separately for fine powder and coarse powder by adjusting the mixing amount.

  In the present invention, a part of the coarse powder that has been easily pulverized compared to the state before the drying process is pulverized by a pulverized coal machine (mill) and transferred to the burner with a low-temperature carrier gas. By igniting, the safety against the spontaneous ignition of the fuel on the transport system and the ignitability of the fuel in the burner are ensured.

  In addition, the present invention minimizes equipment and processes for pulverizing coarse particles that require a fine pulverizer that requires a large amount of power, cost, and maintenance costs. The fuel is supplied to the same burner as the main fuel, and the carrier gas temperature is increased immediately before the supply, thereby promoting combustion and improving boiler efficiency.

  Usually, it is possible to make coarse particles into coarse powder at 1/2 to 1/10 of the power for finely pulverizing coarse particles (power of fine pulverizer), and if it can be burned efficiently, Power generation efficiency can be improved.

For example, the power generation efficiency of a 1000 MW plant accounts for 0.5% of the power of the mill (pulverized coal machine) and primary air fan, and the number of mills (pulverized coal machine) and primary air fans can be reduced to about 1/5. Therefore, the ratio of the power of the mill (pulverized coal machine) and the primary air fan to the power generation efficiency is only 0.1%, which is an improvement of 0.4%. Therefore, if the power transmission end efficiency is 40%, the plant is expected to improve efficiency by 1%. In addition, by reducing the number of mills (pulverized coal machines), facilities can be simplified (lower cost) and maintenance costs can be reduced.
In addition, the present invention is not limited to brown coal, and can be widely applied to solid fuels that have a high water content and a high pulverization power.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the wind for supplying the drying gas from below the conveying member for forming the fluidized bed of the conveyed object into the conveying member. By using a conveyor device provided with boxes, the coarse coal can be efficiently and evenly dried by forming a fluidized bed.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, the third high-temperature carrier gas for coarse powder connecting the second high-temperature carrier gas pipe for coarse powder via a hot air mixer. A pipe and a fourth high-temperature carrier gas pipe for coarse powder; and a hot air mixer connected to the fifth high-temperature carrier gas pipe for coarse powder branched from the second high-temperature carrier gas pipe for coarse powder. Thus, the volatile matter in the coarse coal reaching the burner is diffused and becomes easy to burn.

According to invention of Claim 4, when many fine powder is contained in the coarse powder of coal, installation of the said fine powder supply system is abbreviate | omitted, and 3rd high-temperature carrier gas piping for coarse powder (107 ) And a hot air mixer (13), the fine powder is separated by a cyclone separator (41) for separating the fine powder, and the obtained fine powder is directly passed through the fine powder conveyance pipe (46) to the solid fuel burner (15 ).

  According to the invention described in claim 5, in addition to the effect of the invention described in claim 1, the transfer amount in the transfer channel to the burner is set to the transfer gas (air) for each of the coarse coal and pulverized coal. It can be controlled appropriately according to the temperature and the coal supply command value, does not send the amount of carrier gas (air) excessively into the burner, and does not reduce the coal concentration more than necessary. It is possible to secure a minimum flow velocity that does not stagnate.

According to the sixth aspect of the present invention, the fine powder ejected to the tip of the solid fuel burner in the first aspect of the invention is rolled up behind the flame holding ring to form a stable flame, and the coarse powder is inside the fine powder. By steaming and baking, the coarse powder is also gasified and easily burned.

The main block diagram of the whole combustion system which consists of the coarse powder and fine powder of one Example of this invention is shown. The combustion system figure of the coarse powder of one example of the present invention is shown. The combustion system figure of the fine powder of one example of the present invention is shown. The side sectional view of the burner for coarse powder combustion of one example of the present invention is shown. The combustion system figure of the coarse powder of other examples of the present invention is shown. It is a systematic diagram of the whole drying conveyor apparatus which concerns on the Example of this invention. It is a schematic block diagram of the drying conveyor apparatus main body which concerns on the Example of this invention. It is a perspective view of the apron used for the drying conveyor apparatus main body of FIG. It is an expanded sectional view on the AA line of FIG. It is an expanded sectional view on the BB line of FIG. It is a schematic side view which shows the arrangement | positioning state of the apron of FIG.

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

FIG. 1 shows a main configuration diagram of an entire combustion system composed of coarse powder and fine powder according to an embodiment of the present invention.
The lignite under 50 mm in the coal bunker 37 is pulverized to an average particle size of several millimeters (for example, about 2 mm) by a two-stage coarse pulverizer 38 to become coarse powder (see FIG. 6 for details). Then, it is dried until the moisture content becomes 10 to 20% in the dryer 39 and stored in the coarse powder hopper 1.
The coarse powder system includes a rotary valve 2 and a fuel shut-off valve 3 provided in an outlet pipe of the coarse powder hopper 1. The coarse powder that has passed through them is mixed with air by the coarse powder mixer 5 and then sent to the burner 15 of the boiler 124. It is carried.

  On the other hand, instead of the coarse particle mixer 5, a mill 24 is installed, and the pulverized coal pulverized to about 2 mm in the coarse hopper 1 is crushed into pulverized coal by the mill 24, and the rotary valve 2 provided in the mill outlet pipe And there is a fine powder part for sending fine powder to the burner 15 via the fuel shut-off valve 3, and the coarse coal and the fine coal are burned simultaneously in the same burner 15. A spare mill 24 is also provided with the mill 24 as a regular machine.

  Although not shown in FIG. 1, the configuration of the coal bunker 37, the coarse pulverizer 38, and the dryer 39 is provided for each coarse hopper 1. However, the configurations of the coal bunker 37, the coarse pulverizer 38, and the dryer 39 may be shared by the plurality of coarse powder hoppers 1.

  In addition, when trying to burn the coarsely pulverized and dried coarse lignite, the solid fuel burner 15 has low ignitability, it is difficult to continuously burn, and unburned residue is generated. Although there is a problem that the ratio of fuel falling to the furnace bottom of the boiler 124 increases, the present invention can also solve such a problem.

FIG. 2 is a detailed configuration diagram of the coarse powder combustion system shown in FIG. In the boiler 124, the main carrier gas pipe (also referred to as a first high-temperature carrier gas pipe for coarse powder) 105 exiting from the FDF (push-in fan) 6 is used as a gas preheater (boiler exhaust gas, combustion gas, and fuel carrier gas). In general, this is called an air preheater: an air heater.Hereinafter, it may be referred to as an air preheater or AH.) 18 is supplied to the burner 15 of the boiler 124 and the after air port (AAP) 16 via the preheated air. Supplied as coal for combustion. The main carrier gas pipe 105 leading to the burner 15 and the main carrier gas pipe 105 leading to the after air port (AAP) 16 are provided with a burner air proportional control valve 43 and an after air oxygen control valve 44, respectively. The opening degree of the burner air proportional control valve 43 and the oxygen control valve 44 is controlled based on the detected values of the load and the fuel flow rate.

Further, the exhaust gas discharged from the boiler 124 passes through the exhaust gas line 111 and is exchanged with the air from the FDF 6 by the gas preheater 18 and discharged to the outside. The air preheated by the air preheater 18 warms the coal combustion air supplied to the burner 15 and the after-air port (AAP) 16.
Further, the cold air in the main carrier gas pipe 105 at the outlet of the FDF 6 branches before entering the air preheater 18, passes through the first coarse powder low temperature carrier gas pipe 106, and passes through the first coarse powder low temperature carrier gas. Measurement of the hot air flow meter 12 that measures the air flow rate by the transfer air flow meter 9 provided in the pipe 106, and measures the measured value and the hot air flow rate of the fifth coarse powder high-temperature transfer gas pipe 112 described later. The sum of the values is integrated by an integrator 116, and a deviation between the integrated value and the set air flow rate value from the coal supply request value (coal supply command signal) 115 transmitted from the boiler control is calculated by a deviator 117. The high air pressure selector 118 provided in the first coarse powder low temperature carrier gas pipe 106 by the high value selector 118 so that the actual measurement value measured by the carrier air flow meter 9 becomes the set air flow rate value. Adjust 7

On the other hand, a part of the air that has exited from the AH (air preheater) 18 is coarsely powdered by the transfer air temperature adjustment damper 8 provided in the second high-temperature carrier gas pipe 109 for coarse powder branched from the main carrier gas pipe 105. The supply amount is controlled so that the outlet temperature of the mixer 5 becomes constant. The opening degree of the conveying air temperature adjusting damper 8 is controlled based on the outlet temperature of the coarse powder mixer 5 measured by the thermometer 11.

The air in the first coarse powder low-temperature carrier gas pipe 106 passes through the air shutoff valve 10 and enters the coarse powder mixer 5. The outlet of the second high-temperature carrier gas pipe 109 for coarse powder is connected to the first low-temperature carrier gas pipe 106 for coarse powder downstream from the installation portion of the carrier air flow rate adjustment damper 7. Then, the air flow rate downstream of the connecting portion between the second coarse powder high-temperature carrier gas pipe 109 and the first coarse powder low-temperature carrier gas pipe 106 is measured by the carrier air flow meter 9. The first coarse powder low temperature carrier gas pipe 106 on the downstream side of the carrier air flow meter 9 is provided with an air shut-off valve 10 necessary for stopping the supply of air to the burner 15.

Further, an emergency purge steam supply pipe 110 having an emergency purge steam cutoff valve 22 for stopping air supply in an emergency is connected to the first coarse powder low temperature carrier gas pipe 106 on the downstream side of the air cutoff valve 10. ing. The coarse powder mixer 5 is disposed in the downstream portion from the connection portion of the first coarse powder low-temperature carrier gas pipe 106 with the emergency purge steam supply pipe 110, and the third coarse powder mixer 5 is disposed on the downstream side of the third coarse powder mixer 5. coarse powder for hot carrier gas pipe 107 is provided with, the coarse powder for high temperature carrier gas pipe 107 of the third to about 0.99 ° C. air flow supplied to the hot air mixer 13. The air heated to about 250 ° C. by the hot air mixer 13 passes through the fourth high-temperature carrier gas pipe 108 for coarse powder, and is supplied to the burner 15 together with the coarse coal.
The coarse powder is supplied from the coarse powder hopper 1 via the rotary valve 2 and the fuel cutoff valve 3 to the coarse powder mixer 5 as described with reference to FIG.

Also, a fifth coarse powder high temperature carrier gas pipe 112 branched from the second coarse powder high temperature carrier gas pipe 109 on the upstream side from the installation portion of the carrier air temperature adjustment damper 8 is connected to the hot air mixer 13. since it is, toward the hot air mixer 13 from the fifth coarse powder for high temperature carrier gas pipe 112, the opening degree of the hot-air mixing damper 42 provided in the coarse powder for high temperature carrier gas pipe 112 of the fifth control The high temperature carrier gas (air) is sent. The opening degree of the hot air mixing damper 42 is determined by the measured value of the hot air temperature measured by the burner inlet thermometer 14 provided in the fourth high-temperature carrier gas pipe 108 for coarse powder and the hot air amount command by the hot air amount commander 123. Control is based on the signal. Further, a deviation between a minimum air flow signal calculated by a deviation calculator 119 (to be described later) and a measured value of the carrier air flow meter 9 is also transmitted to the hot air flow command unit 123 to be used for calculation of the hot air flow command signal.

  Here, the air shut-off valve 10 disposed in the first coarse powder low-temperature carrier gas pipe 106 closes quickly when the plant trips due to MFT (main fuel cut-off), and the coarse powder mixer 5 and the burner 15 are closed. The emergency purge steam shut-off valve 22 is opened and the emergency purge steam 21 is sent into the furnace of the boiler 124 to purge the inside of the furnace with the emergency purge steam 21 and, in the unlikely event, the coarse powder remaining between Even if there is coal remaining between the powder mixer 5 and the burner 15, the ignition of the coal is suppressed by reducing the oxygen concentration with steam.

  Coarse coal stored in the coarse powder hopper 1 is supplied to the coarse powder mixer 5 via the rotary valve 2 and the fuel cutoff valve 3 provided in the coarse powder supply pipe 114. Then, the supply amount is controlled by the rotational speed of the rotary valve 2 that matches the amount of coal supply required by the boiler 124. The fuel cutoff valve 3 is closed when MFT occurs to shut off the fuel. On the other hand, the hot air in the coarse powder mixer 5 rises upward by the amount of coal falling into the coarse powder mixer 5, and the temperature of the rotary valve 2 and the like rises, which may cause the coal to ignite. Air 4 is introduced into the coarse powder supply pipe 114 to suppress the rise of warm air. Since the amount of volatile matter in lignite is about 180 ° C. and the amount of emission rapidly increases, the temperature of the seal air 4 is set to about 150 ° C., for example, in order to keep it lower than this.

The coarse powder and hot air that have exited the coarse powder mixer 5 enter the hot air mixer 13 via the third high-temperature carrier gas pipe 107 for coarse powder, and the temperature further rises. Further, air is conveyed from the hot air mixer 13 to the burner 15 via the fourth coarse powder high-temperature carrier gas pipe 108.

In the hot air mixer 13, the opening degree of the hot air mixing damper 42 in which the outlet air of the air preheater 18 sent from the second high-temperature carrier gas pipe 109 for coarse powder is provided in the fifth high-temperature carrier gas pipe 112 for coarse powder. Control the flow. At this time, the temperature of the carrier air conveyed from the hot air mixer 13 to the burner 15 measured by the burner inlet temperature measuring device 14 provided in the fourth coarse powder high-temperature carrier gas pipe 108 and the hot air amount command signal 123 The accumulated value is accumulated by the accumulator 120, the opening degree of the hot air mixing damper 42 is controlled, and the fifth high-temperature conveying for coarse powder is performed so that the burner inlet temperature measured by the burner inlet temperature measuring device 14 becomes the specified temperature. The branch air flow rate in the gas pipe 112 is controlled. Note that a signal from a deviation calculator 119 for calculating a deviation between the minimum air flow signal and the measured value of the carrier air flow meter 9 is sent to the hot air flow command device 123. For example, the length of the pipe 108 to the extent that the hot air at 250 ° C. in the fourth high-temperature carrier gas pipe 108 for coarse powder reaches the burner 15 in 1 to 2 seconds is set to 15 to 30 m, for example, in lignite The volatile matter is just released and becomes easy to burn.

  Further, the carrier air flow rate adjustment damper 7 in the first coarse powder low-temperature carrier gas pipe 106 is configured so that the amount of air supplied to the hot air mixer 13 and the air entering the coarse powder mixer 5 with respect to the required amount of coal supply. However, even if the amount of air entering the hot air mixer 13 becomes large, the temperature of the conveying air at the outlet of the coarse powder mixer 5 is set so that the air necessary for conveying the coarse powder is secured at a minimum. Based on the result, the opening degree of the carrier air temperature adjusting damper 8 is controlled, and the flow rate of the low-temperature carrier gas (air) for coarse powder flowing into the coarse powder mixer 5 is controlled.

Further, when the actual air amount approaches the minimum air amount necessary for the coarse powder conveyance, the set temperature of the burner inlet thermometer 14 is lowered so that the opening degree of the hot air mixing damper 42 is lowered, and the coal concentration of the burner 15 is required. Control so as not to decrease any more.
That is, when the amount of coal to be transported decreases, the air also correspondingly decreases. However, in order to prevent stagnation of the coal in the transport piping, it is necessary to introduce air at the minimum flow rate. In this case, if the air temperature setting before entering the burner 15 remains high, more air is supplied from the mixer 13, and the ratio of air to coal increases, resulting in a decrease (thinning) in the coal concentration. In order to prevent this from occurring due to misfire, the temperature setting is lowered and the amount of hot air supplied to the hot air mixer 13 is limited.

  The coarse powder charged into the burner 15 is gasified at a high temperature and is easily combusted, but some of the particles having a large particle size (several millimeters) fall to the furnace bottom of the boiler 124. The coal that has fallen to the bottom of the furnace is carried out of the system together with the ash while being burned on the flame-fired conveyor 17.

  The coarse powder particles that enter the furnace of the boiler 124 are completely combusted by the AAP 16 and heat exchanged in the boiler 124, and then pass through the air preheater 18 and the electric dust collector 19, and a chimney (not shown) by the IDF (attracting fan) 20. ).

FIG. 3 shows a combustion system diagram of fine powder.
2 differs from the coarse powder combustion system of FIG. 2 described above in that instead of the coarse powder mixer 5 of FIG. first to set up a primary air fan 23 in the upstream side of the 'air shutoff valve 10' finely powdered low-temperature carrier gas pipe 106, and a hot air mixer 13 of FIG. 2 in order to compensate for the pressure loss in the It is not installed, and the fifth high-temperature carrier gas pipe 112 for coarse powder that sends hot air to the hot air mixer 13 and related equipment are not installed.
The reason why the hot air mixer 13 of FIG. 2 is not installed in the combustion system diagram of the fine powder of FIG. 3 is that the pulverized coal is obtained by the mill 24, so that the flame holding property of the burner 15 can be improved without installing the heat mixer 13. This is because there is no problem.

The carrier gas piping in the combustion system diagram of fine powder in FIG. 3 corresponding to the carrier gas piping in the combustion system diagram of coarse powder in FIG. . For example, a first coarse powder for the low-temperature carrier gas pipe 106 or the main carrier gas pipe 105 similar to that Figure 3 of the first fine powder for the low-temperature carrier gas pipe 106 'or the main carrier gas combustion system diagram of fines FIG Piping (also referred to as the first high-temperature carrier gas piping for fine powder) 105 'is given a dash symbol.
The coarse powder is supplied for each burner 15, while the fine powder can be supplied to all the burners 15 by one mill 24. However, a spare mill 24 may be installed, and two mills 24 may be combined.

Gas preheater (AH) 18 inlet of supply branches 'part of the air in the first fine powder for the low-temperature carrier gas pipe 106 as conveying air for the pulverized coal' main carrier gas pipe 105 to the, transport The air flow adjustment damper 7 ′ controls the value of the primary air flow meter 9 ′ to be an air amount commensurate with the coal supply command. That actually measured air flow rate by the first 'conveying air flow control damper 7 provided in the' fine flour for the low-temperature carrier gas pipe 106 and conveying air flow meter 9 ', is transmitted from the measured value and the boiler control Deviation of the set air flow rate value from the requested coal feed amount (coal feed amount command signal) 115 ′ is calculated by the deviator 117 ′ and conveyed by the high value selector 118 ′ so that the measured value becomes the set air flow rate value. Adjust the air flow adjusting damper 7 '.

On the other hand, the first fine powder from and a second fine powder for high temperature carrier gas pipe 109 which is provided 'branch' hot air main carrier gas pipe 105 'in the main carrier gas pipe 105 at the outlet of the gas preheater 18 Although via the use cold carrier gas pipe 106 'is supplied to the mill 24, so the outlet temperature measured at an outlet temperature gauge 27 of mill 24 is the set value, the hot conveying gas piping for a second fine powder controlling the air (warm air) of the second in the fine powder for high temperature carrier gas pipe 109 '' conveying air temperature control damper 8 of the '109. Although the first air temperature during the fine powder for the low-temperature carrier gas pipe 106 'of the mill 24 the inlet is measured by a temperature gauge 28, so that the air temperature at the inlet of the mill 24 is not higher than necessary, the temperature gauge 28 It has a function of biasing the control temperature with the mill inlet temperature measured in (1).
That is, if the inlet temperature of the mill 24 is too high, the volatile matter in the coal is gasified and becomes a flammable gas, which is in a dangerous state. Therefore, if the inlet temperature exceeds 150 ° C, a bias is provided at the mill outlet temperature. Do not exceed 150 ° C.

Air This first fine powder for the low-temperature carrier gas pipe 106 of the upstream side of the first fine powder for the low-temperature carrier gas pipe 106 'of the air shutoff valve 10' of the upstream primary disposed on the side of the air fan 23 ' The temperature is measured by the mill inlet thermometer 28, and the total value of the command value of the temperature setting command device 121 and the measured value of the mill outlet thermometer 27 when the measured value of the mill inlet temperature is 150 ° C. or less is calculated by the integrator 122. The opening degree of the carrier air temperature adjustment damper 8 'is controlled.
The conveying air in the first in the fine powder for the low-temperature carrier gas pipe 106 'enters the primary air fan 23, is supplied to the mill 24 is boosted after passage of air shutoff valve 10.

Coarse coal supplied into the mill 24 by the rotation control of the rotary valve 2 disposed in the coarse powder supply pipe 114 from the coarse powder hopper 1 in an amount corresponding to the required amount is pulverized by the pulverization unit of the mill 24 and third. It is supplied to each burner 15 via the fine powder for high temperature carrier gas pipe 107 'of. Mill outlet damper 40 is installed in the third fine powder for high temperature carrier gas pipe 107 'immediately before the burner 15 at each stage, allowing the on / off each burner stage.

Third fine powder for high temperature carrier gas pipe 107 'fines present in up to the burner 15 from the time of closure of the mill outlet damper 40 provided in the first fine powder for the low-temperature carrier gas pipe 106' branches cold conveyance branched from The purge valve 26 provided in the gas pipe 113 supplies and purges the cold air on the upstream side of the air preheater 18. In addition, as shown in an enlarged view, a part of the junction between the third high-temperature carrier gas pipe 107 ′ for fine powder and the branch low-temperature carrier gas pipe 113 in front of the burner 15 is shown in an enlarged view in the round frame of FIG. A flow path configuration is provided in which the low temperature carrier gas (cold air) in the carrier gas pipe 113 can be introduced into the high temperature gas in the third high temperature carrier gas pipe 107 ′ for fine powder.

FIG. 4 is a burner cross-sectional view showing an example of a coarse powder combustion burner.
A mixed flow of coarse powder and primary air (carrier air) enters the primary fuel nozzle 45 in the center of the burner 15, and the coarse coal powder homogenized by constricting the mixed flow with the venturi 29 is fed to the tip of the burner 15. Supplied. On the other hand, the mixed flow of fine powder and primary air is supplied to the secondary fuel nozzle 49 provided on the outer peripheral portion of the primary fuel nozzle 45 and is jetted to the tip of the burner 15 immediately before the flame holding ring 35. The fine powder is rolled back behind the flame-holding ring 35 to form a stable flame, and the coarse powder inside the fine powder is steamed and burned, whereby the coarse powder is also gasified and easily burned.

The air supplied to the burner 15 flows in the secondary air flow 30 flowing in the secondary air nozzle 50 disposed outside the secondary fuel nozzle 49 and in the tertiary air nozzle 51 disposed outside the secondary air nozzle 50. It is divided into the tertiary air flow 32 and adjusted by the secondary vane 31 in the secondary air nozzle 50 and the tertiary register 33 arranged in the tertiary air nozzle 51, and the like, the flame holding property of the fuel in the furnace, the combustion exhaust gas It is possible to adjust the NOx concentration and oxygen distribution in the inside.
If air is excessively supplied at the initial stage of combustion, the NOx concentration is increased. Therefore, the tip of the burner 15 is provided with a guide sleeve 34 for enlarging and flowing combustion air outward, so that the air is burned during solid fuel combustion. Suppressing excessive supply.
An oil burner 36 for starting and emergency can be installed in the center of the burner 15.

Incidentally, a cold carrier gas piping for coarse powder first coarse powder for the low-temperature carrier gas pipe 106 and the first fine powder for the low-temperature carrier gas pipe 106 is cold carrier gas piping for fines' are each crude It may be common to any part before the powder mixer 5 and the primary air fan 23. Similarly, the third high-temperature carrier gas pipe 107 for coarse powder and the third high-temperature carrier gas pipe 107 ′ for fine powder until they are connected to the fourth high-temperature carrier gas pipe for coarse powder 108 are used for coarse powder and fine powder. You may share.

In short, in the carrier gas system for fine powder (fine powder supply system), the gas temperature after the fine powder is introduced into the system from the third high-temperature carrier gas pipe 107 'for fine powder prevents spontaneous combustion of lignite with a high volatile content. For example, from the viewpoint of safely carrying the air current, the upper limit may be controlled, for example, at about 70 ° C.

Similarly, in the carrier gas system for coarse powder, the gas temperature immediately after the coarse powder is introduced into the system from the third high-temperature carrier gas pipe 107 for coarse powder is suppressed to, for example, 150 ° C. from the same viewpoint. The boiler efficiency can be increased while ensuring safety by raising the temperature to 250 ° C. immediately before the burner 15 to be burned.

FIG. 5 shows a combustion system diagram applicable when coarse powder contains a lot of fine powder.
If the coarse powder contains a lot of fine powder, the fine powder separated by the cyclone separator 41 may be used by omitting the installation of the pulverized coal machine 24 arranged in the fine powder combustion system.

Coarse powder and air discharged from the coarse powder mixer 5 are separated by the cyclone separator 41, and the light fine powder moves to the upper part of the cyclone separator 41, and the fine powder pressure adjusting damper 47 provided in the fine powder conveyance pipe 46 is also finely conveyed. The opening degree is adjusted based on the pressure measured by the fine powder pressure gauge 48 provided on the downstream side of the fine powder pressure adjusting damper 47 of the pipe 46. Further, a necessary amount is taken out by the fine powder pressure adjusting damper 42 and sent to the vicinity of the flame holding ring 35 (FIG. 4) via a pipe (not shown).
On the other hand, the coarse powder is extracted from the lower part of the cyclone separator 41 and sent to the hot air mixer 13.

Next, an embodiment used in the above-described embodiment of the present invention will be described with reference to the drawings. First, the configuration of the drying conveyor device will be described.
(Configuration of drying conveyor)
FIG. 6 is a system diagram of the entire drying conveyor apparatus according to the embodiment of the present invention.
As shown in the figure, the drying conveyor device includes a drying conveyor device main body 39, and coarse particle supply means 53 for supplying undried coarse particles 52 such as coal (brown coal) to the drying conveyor device main body 39; It mainly comprises a hot air supply means 54 for supplying hot air for drying to the drying conveyor apparatus main body 39 and a scattered particle collecting means 55 for collecting the scattered and dried fine particles.
The configuration of the drying conveyor device main body 39 will be described later.

  The coarse particle supply means 53 includes a raw material silo 37 for storing the raw material 56 before being pulverized into the coarse particles 52, a pulverizer 38 provided under the raw material silo 37, and pulverizing the raw material 56 into a predetermined size. The pre-drying hopper 59 for storing the coarse particles 52 produced in this manner, the first gate valve 60 provided thereunder, the second gate valve 61 provided therebelow, and the first gate valve 60 And a measuring pipe portion 62 (see FIG. 7) provided between the second gate valve 61 and the second gate valve 61.

  As shown in FIG. 7, the first gate valve 60 and the second gate valve 61 can be individually driven by a cylinder 63. Moreover, the lower end part of the said measuring pipe part 62 is inserted in the drying conveyor apparatus main body 39 (housing 70 mentioned later) (refer FIG. 7).

The hot air supply means 54 includes a suction damper 64, a blower 65, and a heat exchanger 66, and the air supplied to the heat exchanger 66 is heated by, for example, steam extracted from a steam turbine (not shown). .
The scattered particle collecting means 55 has a cyclone separator 68 and a rotary seal 69 provided therebelow.

  7 is a schematic configuration diagram of the drying conveyor apparatus main body 39, FIG. 8 is a perspective view of an apron used in the drying conveyor apparatus main body 39, FIG. 9 is an enlarged cross-sectional view taken along line AA in FIG. 7, and FIG. FIG. 11 is an enlarged cross-sectional view taken along line B-B of FIG.

  In the drying conveyor device main body 39, an apron conveyor 71 is disposed at a substantially intermediate position in the height direction inside the housing 70 extending along the conveying direction of the coarse particles 52. The housing 70 stores an apron conveyor 71 and is cut off from outside air. The apron conveyor 71 is stretched between a driving pulley 72 and a tension pulley (driven pulley) 73 arranged at a predetermined interval. The tension of the apron conveyor 71 can be set by a tension setting device 74 attached to the tension pulley 73, whereby the apron conveyor 71 can be adjusted in elongation and meandering.

  The apron conveyor 71 is composed of a chain conveyor, on which a large number of aprons 75 are aligned and rotatably mounted. As shown in FIG. 8, the apron 75 includes a bottom plate 76, a back plate 77 erected from the downstream end of the apron 75 in the moving direction of the apron 75, and the bottom plate 76 and the back plate 77 for both sides. Reinforcing plates 78a and 78b having side surfaces connected to each other having a substantially triangular shape are provided.

  The upstream side of the apron 75 in the moving direction, most of the left and right side surfaces, and the upper side are released. As shown in FIGS. 8 to 11, the upstream side of the apron 75 in the moving direction is closed by the back plate 77 of the adjacent apron 75 adjacent to the apron 75. The left and right side surfaces of the apron 75 are covered with plate-shaped blow-off preventing members 91a and 91b provided in the housing 70 so as to correspond to the left and right side surfaces. As shown in FIGS. 7 and 11, the blow-by preventing member 91 extends substantially the same length as the distance between the drive pulley 72 and the tension pulley 73. In addition, in FIG. 8, since drawing becomes complicated, illustration of the blow-out prevention member 91b on the near side is omitted.

  Coarse particles 52 are accommodated inside the apron 75 by the bottom plate 76, the back plate 77 standing from the bottom plate 76, the back plate 77 of the adjacent apron 75, and the blow-off preventing members 91a and 91b. A storage space 82 (FIG. 9) is formed. As shown in FIGS. 9 and 10, the upper end portions of the blow-by prevention members 91a and 91b are in an open state.

  A large number of hot air blowing holes 79 are formed in the bottom plate 76. In this embodiment, a punching plate in which a large number of hot air blowing holes 79 are formed is used as the bottom plate 76, but a metal mesh or the like may be used. Further, as shown in FIG. 9, a detected portion 81 for detecting the arrival of the apron 75 is provided near the lower end portion of the left reinforcing plate 78a of each apron 75. Further, a position sensor 93 for detecting that the apron 75 has come under the measuring pipe portion 62 is fixed near the apron 75 (detected portion 81).

  In the present embodiment, the side on which the tension pulley 73 is disposed is the coarse particle 52 supply side, and the side on which the drive pulley 72 is disposed is the coarse particle 52 discharge side. It is intermittently conveyed in the direction of the drive pulley 72, and an arrow X indicates the conveying direction.

  Therefore, as shown in FIG. 7, in the housing portion above the tension pulley 73, the lower end portion of the measuring tube portion 62 of the coarse particle supply means 53 passes through and extends to the vicinity of the apron 75. On the other hand, a discharge port 83 for dried coarse particles 52 is formed in the housing portion below the drive pulley 72.

  As will be described later, when the coarse particles 52 are dropped from the lower end portion of the metering tube portion 62 and are accommodated in the accommodating space 82 of the apron 75, a part of the coarse particles 52 is passed through the hot air blowing holes 79 of the apron 75. It may fall into the conveyor 71. In order to prevent this, as shown in FIGS. 7 and 9, a supply side blocking plate 84 a for closing the hot air blowing hole 79 of the apron 75 that has come to the lower side of the measuring pipe portion 62 is provided below the apron 75. is set up. A discharge side blocking plate 84 b for preventing the coarse particles 52 from falling from the hot air blowing holes 79 is also installed in the vicinity of the drive pulley 72.

  As shown in FIG. 7, a plurality of wind boxes 85 are continuously installed below the apron 75 along the conveying direction X of the coarse particles 52 between the supply-side blocking plate 84 a and the discharge-side blocking plate 84 b. Has been. As shown in FIG. 10, the wind box 85 has a bottom plate 86 that is inclined downward toward one end, both side plates 87 a and 87 b erected from the bottom plate 86, and hot air introduced to the shorter side plate 87 a. A tube 88 is provided, and the upper opening of the wind box 85 faces the bottom plate 76 of the apron 75.

  Falling particle discharge holes 89 are provided in the vicinity of the lower end of the longer side plate 87 b opposite to the shorter side plate 87 a having the hot air introduction pipe 88 or at the lower end of the bottom plate 86. Further, as shown in FIG. 6, hot air supply pipes 90 extending from the hot air supply means 54 are connected to the hot air introduction pipes 88 of the respective wind boxes 85.

  Further, on the inner bottom surface of the housing 70, a cleaning chain conveyor 94 is disposed along the longitudinal direction of the housing 70. The cleaning chain conveyor 94 is driven to rotate in the direction of the arrow Y by a driving pulley 95 and a driven pulley 96 at all times or at predetermined time intervals so as to sweep the inner bottom surface of the housing 70.

  In the present embodiment, the inner bottom surface of the housing 70 is in a horizontal state. However, if the inner bottom surface of the housing 70 is inclined slightly toward the discharge port 83 side, the cleaning efficiency by the cleaning chain conveyor 94 is improved. Will be better.

  As shown in FIG. 7, a fine particle collecting pipe 97 extending to the cyclone separator 68 side is connected to the upper surface portion of the housing 70. On the other hand, the particulate feed pipe 98 extending from the rotary seal 69 extends from the outside of the housing 70 to the discharge port 83 side.

Next, operation | movement of this drying conveyor apparatus is demonstrated.
(Operation of drying conveyor)
As shown in FIG. 6, a raw material 56 made of lignite having a water content of about 40 to 50% by weight, for example, stored in the raw material silo 37 is pulverized by a pulverizer 38, and the particle size is about 1 mm. The particles 52 are stored in the hopper 59 before drying. When the upper first gate valve 60 is opened with the lower second gate valve 61 closed, a part of the coarse particles 52 in the pre-drying hopper 59 passes through the first gate valve 60, The measuring tube portion 62 (see FIG. 7) is filled, and the coarse particles 52 corresponding to the volume of the measuring tube portion 62 are measured. After the coarse particle 52 is filled in the measuring pipe portion 62, the first gate valve 60 is closed. The gate valves 60 and 61 are opened and closed by cylinders 63 (see FIG. 7) provided separately.

  As shown in FIG. 7, the apron conveyor 71 moves intermittently or continuously in the conveying direction X, and as shown in FIG. 9, the apron 75 has arrived at the lower side of the measuring pipe portion 62. Detected by the joint action of the detected portion 81 attached to 75 and the position sensor 93. When the apron 75 comes to the lower side of the measuring pipe portion 62, all the hot air blowing holes 79 of the apron 75 are closed by the supply side blocking plate 84 as shown in FIG.

  When the second gate valve 61 is opened in this state, the coarse particles 52 stored in the measuring pipe portion 62 fall into the accommodating space 82 of the apron 75. After the coarse particles 62 fall, the second gate valve 61 automatically closes and is ready for the next metering. As described above, since the hot air blowing hole 79 of the apron 75 is blocked by the closing plate 84, the charged coarse particles 52 do not fall from the hot air blowing hole 79, and the measurement amount is properly maintained. Yes.

  FIG. 9 shows a state in which the coarse particles 52 thus weighed and cut out are accommodated in the apron 75. At this time, since the hot air 99 described later is not blown into the apron 75, the coarse particles 52 are coarse. The layer formed by the particles 52 is a stationary layer, and a sufficient space portion 100 remains in the upper portion of the accommodation space 82.

As shown in FIGS. 6 and 10, the hot air 99 generated and supplied by the hot air supply means 54 (see FIG. 6) is blown into each wind box 85 (see FIG. 10). On the other hand, when the hot air blowing hole 79 formed in the bottom plate 76 of the apron 75 passes through the closing plate 84 with the movement of the apron 75, the hot air blowing hole 79 is opened in the wind box 85, and the wind box 85 is opened. The introduced warm air 99 blows in from the bottom of the apron 75, and the coarse particles 52 begin to be in a fluidized state (referred to as arrow 101). If only the warm air 99 passes between the coarse particles 52, only one surface of the coarse particles 52 is dried, but the coarse particles 52 are floated and fluidized in a non-directional and irregular manner as in this embodiment ( By using the arrow 101), the entire surface of the coarse particles 52 can be dried uniformly and rapidly.
The blow-through preventing members 91a and 91b are provided so that the coarse particles 52 that have been fluidized and blown up are not blown out from the apron 75.

  Since the specific gravity of the coarse particles 52 gradually decreases during the drying process, the wind box 85 is divided into a plurality of portions along the conveying direction X of the coarse particles 52 as shown in FIG. The air volume of warm air 99 has been adjusted accordingly. If the warm air 99 is not adjusted, a part of the coarse particles 52 blows out of the wind box 85 and falls or is spontaneously ignited during drying, which is not preferable.

  The coarse particles 52 are dried to a desired moisture content (in the case of lignite according to the present embodiment, about 5 to 10% by weight) by passing over a plurality of wind boxes 85, and as shown in FIG. Since 75 is automatically tilted when turning around the drive pulley 72 from the upper side to the lower side, and finally becomes an upside down state, the dried coarse particles 52 fall to the discharge port 83 side, It is taken out from the housing 70.

  As shown in FIG. 7, a plurality of air ejection nozzles 92 for forcibly blowing coarse particles 52 remaining in the apron 75 are provided obliquely below the drive pulley 72. The inverted apron 75 passes under the air ejection nozzle 92, and the air jetted from the air ejection nozzle 92 is a hot air blowing hole formed in the bottom plate 76 of the apron 75. Through 79, the coarse particles 52 adhering in the apron 75 are blown off. This high-speed jet of air also serves to clean the hot air blowing hole 79 and the inner surface of the apron 75, so that the proper fluidized state of the coarse particles 52 in the apron 75 can always be maintained.

  The coarse particles 52 that have fallen to the bottom surface of the housing 70 in this way, or the coarse particles 52 that have fallen to the bottom surface of the housing 70 from the falling particle discharge hole 89 of the wind box 85 are swept to the discharge port 83 side by the cleaning chain conveyor 94. Is issued. Since the coarse particles 52 falling to the bottom surface of the housing 70 from the falling particle discharge hole 89 of the wind box 85 are also sufficiently in contact with the hot air 99 and dried, the coarse particles 52 are discharged from the discharge port 83 together with other dry coarse particles 52. It can be discharged.

  On the other hand, the fine particles soared by the hot air 99 are collected by the cyclone separator 68 through the fine particle collecting pipe 97, passed through the rotary seal 69, and sent to the discharge port 83 side of the housing 70 by the fine particle feed pipe 98. Since the fine particles soared by the hot air 99 have a faster drying time than the coarse particles 52, the drying is completed in the process of being conveyed to the cyclone separator 68. There is no problem even if it is mixed with the dried coarse particles 52.

  As shown in FIG. 7, it is structurally difficult to place the final wind box 85 (the rightmost wind box 85 in FIG. 7) adjacent to the drive pulley 72. Gaps are created. Therefore, in the present embodiment, the discharge side blocking plate 84b is installed between the final wind box 85 and the drive pulley 72, and the hot air blowing holes 79 of the apron 75 passing there between are closed, thereby drying the coarse particles 52 dried. Is prevented from falling near the drive pulley 72.

DESCRIPTION OF SYMBOLS 1 Coarse grain hopper 2 Rotary valve 3 Fuel shut-off valve 4 Seal air 5 Coarse powder mixer 6 FDF (push-in fan)
7, 7 'Conveyance air flow rate adjustment damper 8, 8' Conveyance air temperature adjustment damper 9, 9 'Conveyance air flow rate 10, 10' Air shut-off valve 11 Mixer outlet temperature 12 Hot air flow meter 13 Hot air mixer 14 Burner inlet temperature 15 Burner 16 AAP (After Airport)
17 Conveyor for open flame combustion 18 Gas preheater (Air heater; AH)
19 EP (electric dust collector) 20 IDF (attracting blower)
21 Emergency purge steam 22 Emergency purge steam cutoff valve
23 Primary air fan 24 mil (fine grinding machine)
26 Purge valve 27 Mill outlet temperature 28 Mill inlet temperature 29 Venturi 30 Secondary air 31 Secondary vane 32 Tertiary air 33 Tertiary resistor 34 Guide sleeve 35 Flame holding ring 36 Oil burner 37 Coal bunker 38 Coarse grinder 39 Dryer 40 Mill outlet Damper 41 Cyclone Separator 42 Hot Air Mixing Damper 43 Burner Air Proportional Control Valve 44 Oxygen Control Valve 45 Primary Fuel Nozzle 46 Fine Powder Transfer Piping 47 Fine Powder Pressure Adjustment Damper 48 Fine Powder Pressure Gauge 49 Secondary Fuel Nozzle 50 Secondary Air Nozzle 51 Secondary Air Nozzle 52 Coarse particles 53 Coarse particle supply means 54 Hot air supply means 55 Scattered particle collection means 56 Raw material 59 Pre-drying hopper 60 First gate valve 61 Second gate valve 62 Metering pipe section 63 Cylinder 64 Suction damper 65 Blower 66 Heat exchange 68 cyclone separator 69 b -Tally seal 70 Housing 71 Apron conveyor 72 Drive pulley 73 Tension pulley (driven pulley) 74 Setting device 75 Apron 76 Bottom plate 77 Back plate 78a, 78b Reinforcement plate 79 Hot air blowing hole 81 Detected portion 82 Storage space 83 Discharge port 84a Supply side blockage Plate 84b Discharge side blocking plates 85, 85a, 85b, 85c, 85d Wind box 86 Bottom plate 87a, 87b Side plate 88 Hot air introduction pipe 89 Falling particle discharge hole 90 Hot air supply pipe 91a, 91b Blow-through prevention member 92 Air jet nozzle 93 Position Sensor 94 Cleaning chain conveyor 95 Drive pulley 96 Driven pulley 97 Particulate collection pipe 98 Particulate return pipe 99 Hot air 100 Space
105, 105 'main carrier gas piping (first coarse powder, high temperature carrier gas piping for fine powder)
106, 106 ′ first coarse powder , fine powder low temperature carrier gas pipe 107, 107 ′ third coarse powder , fine powder high temperature carrier gas pipe 108 fourth coarse powder high temperature carrier gas pipe 109, 109 ′ second Coarse and fine high-temperature carrier gas piping 110, 110 'Emergency purge steam piping 111, 111' Exhaust gas line 112 Fifth coarse powder high-temperature carrier gas piping 113 Branched low-temperature carrier gas piping 114 Coarse powder supply piping 115, 115 ' Coal amount request value (coal supply command signal)
116 Accumulator 117, 117 ′ Deviation device 118, 118 ′ High value selector or its signal 119, 119 ′ Deviation calculator 120 Accumulator 121 Temperature setting command device 122 Accumulator 123 Hot air flow command device 124 Boiler

Claims (6)

The solid fuel boiler (124) having a plurality of burner groups each including two or more solid fuel burners (15, 15,...), And the exhaust gas, combustion gas, and carrier gas from the boiler (124) are heated. A solid fuel boiler system having a gas preheater (18) to be replaced,
Each solid fuel burner (15) is connected with a coarse powder supply system and a fine powder supply system for introducing and burning solid fuel coarse powder and fine powder in separate systems.
The coarse powder supply system is
A first coarse powder high-temperature carrier gas pipe (105) for introducing a solid fuel carrier gas into the solid fuel burner (15) via the gas preheater (18);
A first coarse powder low temperature carrier gas pipe (106) branched from the first coarse powder high temperature carrier gas pipe (105) on the upstream side of the gas preheater (18);
A second branch branched from the first coarse powder high temperature carrier gas pipe (105) on the downstream side of the gas preheater (18) and connected to the first coarse powder cold carrier gas pipe (106). High-temperature carrier gas pipe (109) for coarse powder,
In order to mix the coarse powder of solid fuel provided on the downstream side of the connecting portion where the second coarse powder high temperature carrier gas pipe (109) is connected to the first coarse powder low temperature carrier gas pipe (106). Coarse powder mixer (5),
Third and fourth coarse powder high-temperature carrier gas pipes (107, 108) for supplying coarse powder from the coarse powder mixer (5) to the solid fuel burner (15),
The fine powder supply system is
A first high-temperature carrier gas pipe for fine powder (105 ′) for introducing a solid fuel carrier gas into the solid fuel burner (15) via the gas preheater (18);
A first fine powder low temperature carrier gas pipe (106 ′) branched from the first fine powder high temperature carrier gas pipe (105 ′) on the upstream side of the gas preheater (18);
A second branch branched from the first high-temperature carrier gas pipe (105 ′) for fine powder and connected to the first low-temperature carrier gas pipe (106 ′) for fine powder on the downstream side of the gas preheater (18). High-temperature carrier gas pipe (109 ') for fine powder,
The first low-temperature carrier gas pipe for the fine powder (106 on the downstream side of the connecting portion where the second high-temperature carrier gas pipe for the fine powder (109 ′) is connected to the first low-temperature carrier gas pipe (106 ′) for the fine powder. A carrier gas fan (23) provided in ');
The solid fuel coarse powder connected to the first low-temperature carrier gas pipe (106 ′) for the fine powder on the downstream side of the carrier gas fan (23) is finely pulverized to produce the fine powder of the solid fuel. A fine pulverizer (24) to be supplied to
A third high-temperature carrier gas pipe (107 ′) for supplying fine powder from the fine grinder (24) to the solid fuel burner (15),
The coarse powder supply system includes a plurality of the coarse powder mixers (5) corresponding to the plurality of burner groups (15, 15,...), And the fine powder supply system includes the fine pulverizer. (24) is provided with at least one unit for the plurality of burner groups (15, 15,...).   A set of drive shafts (72, 73) arranged at a predetermined interval and a set of drive shafts (72, 73) are installed between the set of drive shafts (72, 73). 73) A transport member (75) for forming a fluidized bed of a transported object provided with a gas jetting part (79) that circulates around and accommodates and transports the transported object, and jets a drying gas at the bottom thereof. A conveyor device (39) provided with an air box (85) for supplying the drying gas from below the conveying member (75) into the conveying member (75) by roughly pulverizing solid fuel 2. The solid fuel boiler system according to claim 1, wherein each of the plurality of coarse powder mixers (5) and the pulverized coal machine (24) is provided as a conveyor device for reducing the moisture content of the coarse powder obtained. . The third and fourth high-temperature carrier gas pipes (107, 108) for coarse powder are connected to the third high-temperature carrier gas pipe (107) for coarse powder and the fourth high-temperature for coarse powder connected via a hot air mixer (13). The hot gas mixer (13) is composed of a carrier gas pipe (108), and a fifth coarse powder high temperature carrier gas pipe (112) branched from the second coarse powder high temperature carrier gas pipe (109) is connected to the hot air mixer (13). The solid fuel boiler system according to claim 1, wherein: The installation of the fine powder supply system is omitted, and a cyclone separator (41) for separating fine powder is provided between the third coarse powder high-temperature carrier gas pipe (107) and the hot air mixer (13), and a cyclone separator (41 ) A fine powder transfer pipe (46) having a fine powder pressure adjusting damper (47) for directly transferring the fine powder separated in step) to the solid fuel burner (15) is provided between the cyclone separator (41) and the solid fuel burner (15). The solid fuel boiler system according to claim 3. The fifth coarse powder high-temperature carrier gas pipe (112) is provided with a hot-air mixing damper (42), and is connected to the second coarse powder high-temperature carrier gas pipe (112) at the second downstream side. The coarse air high-temperature carrier gas pipe (109) is provided with a carrier air temperature adjusting damper (8), and the first upstream side of the first coarse powder carrier gas pipe (109) is connected to the first upstream side. A low-temperature carrier gas pipe (106) for coarse powder is provided with a carrier air flow rate adjustment damper (7),
A carrier air flow meter (9) for measuring the carrier air flow rate to the first coarse powder low-temperature carrier gas pipe (106) downstream from the connecting portion with the second coarse powder high-temperature carrier gas pipe (109). )
The hot air flow rate for measuring the flow rate of hot air in the fifth high-temperature carrier gas pipe (112) for coarse powder to the fifth high-temperature carrier gas pipe (112) for coarse powder downstream from the hot air mixing damper (42) A total (12) is provided,
A coarse powder mixer outlet thermometer (11) for measuring the coarse powder mixer outlet temperature is provided in the third high-temperature carrier gas pipe (107) for coarse powder on the outlet side of the coarse powder mixer (5),
The fourth coarse powder high-temperature carrier gas pipe (108) is provided with a burner inlet thermometer (14) for measuring the burner inlet temperature,
Controlling the opening of the carrier air temperature adjusting damper (8) based on the measured value of the coarse powder mixer outlet thermometer (11),
The hot air mixing damper (42) opening degree is calculated based on a deviation value (119) between the coal supply command value and the minimum air flow rate and measured by the hot air command value (123) and the burner inlet thermometer (14). Control based on the integrated value (120),
The opening degree of the carrier air flow rate adjustment damper (7) is set to (i) the measured value of the carrier hot air flow meter (12), the integrated value (116) of the measured value of the air flow meter (9), and the coal supply command value (115 ) And a command signal value (118) calculated by a first deviation signal (117) which is a deviation value from (2) and a second value which is a deviation between the measured value of the air flow meter (9) and the minimum air flow rate. The solid according to claim 1, further comprising a control mechanism for controlling so that a required air amount can be obtained with a minimum air amount as a lower limit based on a command signal value (118) calculated from the deviation signal (119). Fuel boiler system. A burner for solid fuel used in the solid fuel boiler system according to claim 1,
A primary fuel nozzle (45) having a venturi (29) for allowing the mixture of coarse pulverized coal and primary air to flow in the central portion and constricting the mixed flow to the inner wall portion is provided,
A secondary fuel nozzle (49) through which a mixed flow of pulverized coal and primary air flows is provided on the outer periphery of the primary fuel nozzle (45),
Disposing the front end of the outlet of the secondary fuel nozzle (49) ahead of the front end of the outlet of the primary fuel nozzle (45),
A flame holder (35) is provided on the outer periphery of the tip of the outlet of the secondary fuel nozzle (49),
A secondary air nozzle (50) having a secondary vane (31) in the outer periphery of the secondary fuel nozzle (49) and having a guide sleeve in which an outlet portion sequentially expands is provided,
A solid fuel burner characterized in that a tertiary air nozzle (51) having a tertiary resistor is provided on the outer periphery of the secondary air nozzle (50).

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