JP5943574B2 - Combustion furnace - Google Patents

Description

  The present invention relates to a combustion furnace for burning wood chips and wood pellets.

  2. Description of the Related Art Conventionally, as a combustion furnace that burns wood chips and wood pellets and supplies heat to a boiler or the like, there is one configured to form a swirling flow of combustion air in a cylindrical combustion chamber.

  As shown in FIG. 11, this type of combustion furnace includes an air chamber between a cylindrical inner wall 221 that forms a cylindrical combustion chamber 202 therein and an inner wall 221 that is disposed on the outer peripheral side of the inner wall 221. There are an outer wall 241 that forms 204 and a plurality of air passages 207 that are formed in the circumferential direction on the inner wall 221 and supply combustion air from the air chamber 204 to the combustion chamber 202 (see Patent Document 1). .

  In this combustion furnace 201, a screw conveyor 209 that supplies fuel 210 is installed substantially vertically along the central axis of the combustion chamber 202, and a fuel supply port 291 at the tip of the screw conveyor 209 protrudes from the bottom surface of the combustion chamber 202. Are arranged. The fuel supply port 291 of the screw conveyor 209 is provided with a fuel diffusion rod 293 that is connected to the drive shaft 292 of the screw conveyor 209 and is driven to rotate.

  The air passage 207 formed in the inner wall 221 is inclined with respect to the radial direction of the combustion chamber 202 in a horizontal plane and a vertical plane. Thus, the combustion air is supplied in a direction eccentric with respect to the central axis of the combustion chamber 202, and a swirling flow of the combustion air is formed in the combustion chamber 202. The fuel 210 guided by the screw conveyor 209 is discharged from the fuel supply port 291 at the tip of the screw conveyor 209 and dispersed on the bottom surface of the combustion chamber 202 by the fuel diffusion rod 293. Thus, by supplying the fuel 210 and the combustion air in a rotationally symmetrical manner around the central axis of the combustion chamber 202, the wood chips and the like that are harder to burn than the fossil fuel are burned stably.

JP 2007-341409 A

  However, in the conventional combustion furnace 201, the wood chips and wood pellets of the fuel 210 are formed from thinned wood, construction waste, or the like. Therefore, hard incombustible materials such as sand and building hardware fragments are often mixed in the fuel 210. Hard incombustible material mixed in the fuel 210 is separated as the fuel 210 passes through the screw conveyor 209, stays at the lower end of the screw conveyor 209, and moves on the conveying blades 294 of the screw conveyor 209 and the inner surface of the casing 295. There is an inconvenience of promoting wear.

  In order to eliminate such inconvenience, a screw conveyor 209 for supplying fuel 210 is disposed below the combustion chamber 202 in a state inclined with respect to the central axis of the combustion chamber 202 as in the combustion furnace 211 shown in FIG. A configuration in which the tip of the screw conveyor 209 and the fuel supply port 202a provided on the bottom surface of the combustion chamber 202 are connected by a curved conduit 212 is conceivable. According to this combustion furnace 211, since the incombustible material is difficult to be separated when the fuel 210 passes through the screw conveyor 209, the conveying blades 294 of the screw conveyor 209 and the inner surface of the casing 295 are worn by the hard incombustible material. Can be reduced.

  However, in the combustion furnace 211, when the fuel containing incombustible material passes through the conduit 212, the hard incombustible material rubs against the curved surface of the conduit 212. is there.

  Accordingly, an object of the present invention relates to a combustion furnace that burns plant-based regenerated fuel, and provides a combustion furnace that can prevent deterioration of parts accompanying the supply of fuel and can improve durability. .

In order to solve the above problems, the combustion furnace of the present invention is
A combustion furnace for burning plant regenerated fuel,
A cylindrical combustion chamber;
A fuel supply section for supplying fuel into the combustion chamber from a side surface of the combustion chamber;
A primary air supply for supplying combustion air from the bottom of the combustion chamber;
And a secondary air supply unit for supplying combustion air from a side surface of the combustion chamber.

  According to the above configuration, the fuel is supplied from the side surface of the cylindrical combustion chamber by the fuel supply unit, the combustion air is supplied from the bottom surface of the combustion chamber by the primary air supply unit, and the secondary air supply The combustion air is supplied from the side surface of the combustion chamber by the unit. By the combustion air from the primary air supply unit and the combustion air from the secondary air supply unit, the fuel supplied from the fuel supply unit burns in the combustion chamber without deviation. Since the fuel supply unit supplies fuel from the side surface of the combustion chamber, for example, the fuel supply unit can be configured to directly supply fuel to the combustion chamber from a screw conveyor or the like disposed inclined with respect to the central axis of the combustion chamber. . Therefore, it is possible to prevent a decrease in durability due to the fuel supply path of the fuel supply unit. Specifically, like a conventional combustion furnace that supplies fuel from the bottom of the combustion chamber, hard incombustibles are separated from the fuel and the parts of the screw conveyor are worn out in a screw conveyor arranged vertically. Inconvenience can be prevented. In addition, it is possible to prevent the inconvenience that a hard incombustible material rubs against the inner side surface of the conduit connecting the screw conveyor disposed at an inclination and the fuel discharge port to wear the conduit. As a result, in a combustion furnace that burns plant-based regenerated fuel containing hard incombustibles, it is possible to prevent deterioration of the components and improve the durability of the combustion furnace.

  Here, examples of the plant-based regenerated fuel include those obtained by crushing plant-based materials such as wood chips and those obtained by molding plant-based materials such as wood pellets. Plant-based materials include wood-based materials such as sawdust, wood chips, thinning and pruning materials, agricultural materials such as rice straw, rice husks, weeds and bagasse, waste-based materials such as construction waste, and waste paper And paper-based materials such as waste pulp. Further, the plant-based regenerated fuel may be a fuel partially using a plant-based material, such as RPF (Refuse Paper and Plastic Fuel).

  In the combustion furnace of one embodiment, the fuel supply unit is connected to a screw conveyor disposed to be inclined with respect to the central axis of the combustion chamber, and an end of the screw conveyor is opened to a side surface of the combustion chamber. It has a fuel supply port.

  According to the above embodiment, the fuel conveyed by the screw conveyor arranged to be inclined with respect to the central axis of the combustion chamber is burned from the side surface of the combustion chamber through the fuel supply port communicating with the end of the screw conveyor. Supplied indoors. Therefore, fuel can be supplied to the combustion chamber without causing deterioration due to the hard incombustible material contained in the plant-based regenerated fuel.

  The combustion furnace according to an embodiment includes a receiving portion that receives fuel supplied from the fuel supply portion on a bottom surface of the combustion chamber.

  According to the above embodiment, the fuel supplied from the side surface of the combustion chamber is received by the receiving portion on the bottom surface, so that the fuel is stably burned in the combustion chamber.

  In the combustion furnace of one embodiment, the primary air supply unit has a plurality of holes provided in the bottom surface of the combustion chamber.

  According to the said embodiment, combustion air is supplied to a combustion chamber from the bottom face of a combustion chamber through the some hole which a primary air supply part has, and combustion of a fuel is accelerated | stimulated. Here, it is preferable that the plurality of holes of the primary air supply unit are arranged on the outer peripheral side of the receiving unit that receives the fuel on the bottom surface of the combustion chamber.

In the combustion furnace of one embodiment, the secondary air supply unit includes a plurality of combustion air outlets that open to the side surface of the combustion chamber,
A part of the plurality of outlets of the secondary air supply unit is disposed at a position farther from the bottom surface of the combustion chamber than the fuel supply port of the fuel supply unit.

  According to the embodiment, an appropriate amount of combustion air is supplied from the plurality of outlets of the secondary air supply unit to the fuel supplied from the fuel supply port of the fuel supply unit and directed toward the bottom surface. Therefore, it is possible to prevent the disadvantage that the amount of combustion air is excessive and the fuel is melted to cause clinker, and the disadvantage that the amount of combustion air is insufficient and the fuel is incompletely burned can be prevented.

  In the combustion furnace of one embodiment, the secondary air supply unit forms a swirling flow of combustion air in the combustion chamber.

  According to the above-described embodiment, a sufficient amount of combustion air is supplied into the combustion chamber by the swirling flow of the combustion air, and the fuel is stably and completely burned.

  In the combustion furnace of an embodiment, the secondary air supply unit forms a turbulent flow of combustion air in the combustion chamber.

  According to the above embodiment, the turbulent flow of the combustion air promotes the mixing of the combustion components of the fuel and the combustion air, thereby promoting complete combustion of the fuel.

  In the combustion furnace of one embodiment, the secondary air supply unit has an air supply path that faces in a direction inclined with respect to the radial direction of the combustion chamber in a plane perpendicular to the central axis of the combustion chamber.

  According to the embodiment, the combustion air that has passed through the air supply path of the secondary air supply unit is blown out into the combustion chamber in a direction that is eccentric within a plane perpendicular to the central axis of the combustion chamber. Thereby, a swirl flow of combustion air is effectively formed in the combustion chamber.

  In the combustion furnace of an embodiment, the secondary air supply unit has an air supply path that faces in a direction inclined with respect to the radial direction of the combustion chamber in a plane including the central axis of the combustion chamber.

  According to the above-described embodiment, the combustion air that has passed through the air supply path of the secondary air supply unit is inclined toward the bottom surface side or the top surface side of the combustion chamber in a plane including the central axis of the combustion chamber. It is blown out in the direction. By mixing these combustion air with the combustion air flowing in the other direction, a turbulent flow of combustion air is effectively formed in the combustion chamber.

The combustion furnace of an embodiment includes a control unit that controls the fuel supply unit and a blower that supplies combustion air to the combustion chamber,
The control unit controls a fuel supply amount by the fuel supply unit and a blown amount by the blower to adjust a heat amount to be generated in the combustion chamber, a fuel supply amount by the fuel supply unit, and the blower And a standby mode in which the combustion chamber holds the seed fire by controlling the amount of blown air to a smaller amount than in the combustion mode.

  According to the embodiment, the operation of the fuel supply unit that supplies fuel to the combustion chamber and the operation of the blower that supplies combustion air to the combustion chamber are controlled by the control unit. In the combustion mode, the controller controls the amount of fuel supplied by the fuel supply unit and the amount of air blown by the blower to adjust the amount of heat generated in the combustion chamber to a predetermined amount of heat. Thereby, the heat generated in the combustion chamber is adjusted to an amount to be supplied to a thermal device such as a boiler, and the thermal device is appropriately operated. On the other hand, in the standby mode, the control unit controls the amount of fuel supplied by the fuel supply unit and the amount of air blown by the blower to an amount smaller than that in the combustion mode, and holds the seed fire in the combustion chamber. At this time, the supply of heat to the thermal equipment is substantially stopped. In this standby mode, if the amount of combustion air blown into the combustion chamber and the amount of fuel supplied are increased, a predetermined amount of heat can be obtained quickly, so that the combustion mode can be quickly entered. Therefore, a combustion furnace capable of quickly responding to a required change in the amount of heat can be obtained despite the use of plant-based regenerated fuel that is less ignitable than fossil fuel.

It is a mimetic diagram showing a boiler device using a combustion furnace of an embodiment of the present invention. It is a longitudinal section showing a combustion furnace of an embodiment of the present invention. It is a top view which shows an upper air chamber and a lower air chamber. It is a perspective view which shows a bottom plate. It is a perspective view which shows another bottom board. It is sectional drawing which shows the bottom part of the combustion chamber at the time of using another bottom plate. It is a longitudinal cross-sectional view which shows the attachment part to the casing of a screw conveyor. It is a longitudinal cross-sectional view which shows arrangement | positioning of the air supply pipe | tube which forms a secondary air supply part. It is a plane sectional view showing arrangement of the 1st swirl airflow pipe among air supply pipes. It is a plane sectional view showing arrangement of a downdraft pipe among air supply pipes. It is a plane sectional view showing arrangement of the 2nd swirl airflow pipe among air supply pipes. It is a longitudinal cross-sectional view which shows arrangement | positioning of another air supply pipe. It is a schematic diagram which shows the control system of a boiler apparatus. It is a schematic cross section which shows a water heat exchanger. It is sectional drawing which shows the fuel supply part of the conventional combustion furnace. It is sectional drawing which shows a mode that the fuel supply part of the conventional combustion furnace was improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a boiler apparatus configured using a combustion furnace according to an embodiment of the present invention, and FIG. 2 is a diagram showing a combustion furnace used in the boiler apparatus. The combustion furnace 1 used in the boiler apparatus 10 functions as a heat source for the boiler apparatus 10 using wood chips, which are plant-based regenerated fuels, as fuel.

  The combustion furnace 1 includes a cylindrical combustion chamber 2, a water jacket 3 formed so as to surround the outside of the combustion chamber 2, and a cylindrical ring disposed at the approximate center in the height direction on the outer peripheral side of the water jacket 3. A shaped upper air chamber 4 is provided. The combustion chamber 2 is surrounded by a cylindrical combustion chamber wall 21 formed using a castable refractory. The combustion chamber wall 21 may be formed using other fire-resistant materials such as refractory bricks. The water jacket 3 outside the combustion chamber 2 is formed between the combustion chamber wall 21 and the upper casing 31.

  A plurality of air supply pipes 71, 72, 73 as a secondary air supply unit for guiding the combustion air of the upper air chamber 4 to the combustion chamber 2 are fixed to the combustion chamber wall 21 and the upper casing 31 so as to penetrate therethrough. The air supply pipes 71, 72, 73 have an air supply path formed therein, and are fixed to be inclined in a predetermined direction with respect to the radial direction of the combustion chamber 2 as will be described in detail later. Combustion air is supplied to the upper air chamber 4 through an upper air supply pipe 42 provided on the air chamber wall 41 as indicated by an arrow A1. The combustion air supplied to the upper air chamber 4 is supplied to the combustion chamber 2 through the air supply pipes 71, 72 and 73. The high-temperature combustion gas generated by burning the fuel F in the combustion chamber 2 is supplied to the water heat exchanger 14 through the exhaust pipe 22 provided on the upper portion of the combustion chamber wall 21.

  On the bottom surface of the combustion chamber 2, a disc-shaped bottom plate 6 fitted to the lower end of the combustion chamber wall 21 is disposed, and the lower air chamber 5 is disposed below the bottom plate 6. The lower air chamber 5 is formed in a cylindrical lower casing 51. In the bottom plate 6, a plurality of through holes 61, 61,... That form primary air supply portions that guide the combustion air from the lower air chamber 5 to the combustion chamber 2 are formed in the outer diameter portion. A receiving portion 62 for receiving the fuel F is formed on the combustion chamber 2 side of the inner diameter portion of the bottom plate 6. Combustion air is supplied to the lower air chamber 5 through a lower air supply pipe 52 provided in the lower casing 51 as indicated by an arrow A2.

  FIG. 3 is a schematic diagram showing the shapes of the upper air chamber 4 and the lower air chamber 5 in a plan view. As shown in FIG. 3, the upper air supply pipe 42 provided on the side surface of the upper air chamber 4 extends in the tangential direction of the side surface of the air chamber 4. By supplying air in the tangential direction to the upper air chamber 4 through the upper air supply pipe 42, it is possible to form an air flow with little deviation in the circumferential direction in the upper air chamber 4 having a cylindrical ring shape. On the other hand, the lower air supply pipe 52 provided on the side surface of the lower air chamber 5 extends in the radial direction of the lower air chamber 5 in plan view. By supplying air in the radial direction to the lower air chamber 5 through the lower air supply pipe 52, an air flow with less bias is formed in the cylindrical lower air chamber 5. Combustion air is supplied to the upper air chamber 4 and the lower air supply pipe 52 by the blower 20 connected to the upstream side of the upper air supply pipe 42 and the lower air supply pipe 52.

  FIG. 4 is a perspective view showing the bottom plate 6. The bottom plate 6 is formed by casting a castable refractory into a disk shape, and a plurality of through holes 61, 61,... Are formed in an annular region of the outer diameter portion in plan view. A receiving portion 62 is provided in an inner diameter portion that is the inner side in the radial direction of the region in which the through holes 61, 61, ... are formed. The receiving portion 62 is formed of a circular shallow recess formed on the surface facing the combustion chamber 2. The receiving portion 62 receives the fuel F supplied from the screw conveyor 9 as a fuel supply portion. The receiving unit 62 holds the fuel F to be burned when the combustion furnace 1 performs a combustion operation for supplying heat to the water heat exchanger 14. On the other hand, when the combustion furnace 1 performs a standby operation in which heat is not supplied to the water heat exchanger 14, the ignited fuel F is held as a seed flame. If the receiving part 62 holds the seed fire during the standby operation, if the supply amount of the fuel F and the combustion air to the combustion chamber 2 increases, the operation can be quickly shifted to the combustion operation. The fuel F may be supported not only by the receiving portion 62 but also by a portion located on the outer diameter side of the receiving portion 62 of the bottom plate 6.

  As shown in FIG. 5A, a bottom plate 106 in which through holes 61, 61,... Are formed on the entire surface in a plan view may be used. When the bottom plate 106 is used, an opening / closing mechanism that opens and closes the through holes 61, 61,... Of the bottom plate 106 is provided at the bottom of the combustion chamber 2. As shown in FIG. 5B, the opening / closing mechanism includes a disc-shaped shielding plate 64 arranged concentrically at the center of the bottom plate 106, and the shielding plate 64 through the lower air chamber 5 side through holes 61, 61. ,...,...,. When the combustion furnace 1 performs a combustion operation for supplying heat to the water heat exchanger 14, the shielding plate 64 is moved away from the bottom plate 106 by the linear actuator 65, and all the through holes 61, 61,. Is brought into communication between the lower air chamber 5 and the combustion chamber 2. Thereby, combustion air is supplied to the combustion chamber 2 through all the through holes 61, 61,. On the other hand, when the combustion furnace 1 performs a standby operation in which heat is not supplied to the water heat exchanger 14, the shielding plate 64 is brought into contact with the bottom plate 106 by the linear actuator 65, and the through holes 61, 61, ... are closed. Thereby, since the blowing of combustion air stops, the center part of the baseplate 106 can hold | maintain the fuel F, and functions as a receiving part. Thereby, the seed fire can be held at the center of the bottom plate 106 during the standby operation. The opening / closing mechanism may be other than the shielding plate 64 and the linear actuator 65, and other mechanisms such as a rotationally driven shutter installed on the front and back surfaces of the bottom plate 106 may be used. It is sufficient that the through holes 61, 61,... At the center of the face plate 106 can be opened and closed.

  On the side surface of the combustion chamber 2, a screw conveyor 9 is installed as a fuel supply unit that supplies the fuel F. The screw conveyor 9 is formed of a cylindrical casing 91, a rotary drive shaft 92 and a conveying screw 93 arranged in the casing 91, and one end thereof is connected to an input pipe 94 for introducing fuel F. The input pipe 94 is connected to the supply conveyor 12 of the fixed-quantity feeder 11 that stores and supplies the fuel F via the shut-off valve 13. At the other end of the screw conveyor 9, a fuel supply port 91 a that opens to the side surface of the combustion chamber 2 is provided. The center of the fuel supply port 91a in the height direction is installed at a position lower than the region where the plurality of air supply pipes 71, 72, 73 are arranged. The center in the height direction of the fuel supply port 91a may be installed at a position lower than the center in the height direction of the region where the plurality of air supply pipes 71, 72, 73 are arranged. Here, the height direction is substantially the same as the extending direction of the central axis of the combustion chamber 2, and the low side is the side close to the bottom surface of the lower casing 51, and the high side is high. The side is the side close to the top surface of the upper casing 31. The screw conveyor 9 is inclined so that its position increases as it goes from one end to the other end. This makes it difficult for hot combustion air to flow back through the screw conveyor 9.

  The screw conveyor 9 has a linear shape and is disposed so as to be inclined with respect to the central axis of the combustion chamber 2 and to open a fuel supply port 91 a on the side surface of the combustion chamber 2. Therefore, the inconvenience that the inside of the vertical screw conveyor 209 in the conventional combustion furnace 201 is worn by the separated hard incombustible material can be prevented. In addition, it is possible to prevent the inconvenience that the conduit 212 connecting the screw conveyor 209 and the fuel supply port 202a disposed at an inclination as in the conventional combustion furnace 211 is worn by a hard incombustible material. Therefore, even if this combustion furnace 1 burns the plant-type regenerated fuel containing a hard incombustible material, there is little deterioration of a component and it has high durability.

  FIG. 6 is a cross-sectional view showing the vicinity of the other end of the screw conveyor 9. As shown in FIG. 6, the other end of the screw conveyor 9 is installed through the water jacket 3, and inside the sheath tube 95 fixed to the combustion chamber wall 21 and the upper casing 31, the screw conveyor 9. Casing 91 is connected. A flange 91b provided on the outer peripheral surface of the casing 91 of the screw conveyor 9 is fixed to a flange 95a provided on the outer end of the upper casing 31 of the sheath tube 95 with a bolt. Thereby, the screw conveyor 9 can be easily attached to and detached from the main body of the combustion furnace 1, and the maintenance inspection of the screw conveyor 9 is easily performed. Further, heat transfer from the water jacket 3 or the combustion chamber 2 into the screw conveyor 9 can be reduced.

  The water jacket 3 heats the water supplied from the hot water storage tank 15, and the water from the hot water storage tank 15 is introduced into the heating feed pipe 33 connected to the lower part of the upper casing 31, as indicated by an arrow W1. Is done. Water heated by receiving heat from the combustion chamber 2 in the water jacket 3 is discharged from the drain pipe 32 connected to the upper portion of the upper casing 31 toward the water heat exchanger 14 as indicated by an arrow W2. .

  FIG. 7A is a longitudinal sectional view showing an arrangement state of a plurality of air supply pipes 71, 72, 73 as a secondary air supply unit. 7A is a cross-sectional view showing a state in which the combustion chamber wall 21 and the upper casing 31 are cut in a plane including the central axis of the combustion chamber 2 at the installation positions of the air supply pipes 71, 72, 73. In addition, in FIG. 7A, the inclination with respect to the radial direction of the air supply pipes 71 and 73 is not expressed. As shown in FIG. 7A, in the combustion furnace 1 of the present embodiment, three stages of air supply pipes 71, 72, 73 are arranged in the extending direction of the central axis of the combustion chamber 2. Among these air supply pipes 71, 72, 73, the air supply pipe located closest to the top surface of the combustion chamber 2 is a first swirling airflow pipe 71 parallel to a plane perpendicular to the central axis of the combustion chamber 2. is there. The first swirl airflow pipe 71 is disposed at an inclination angle α in the clockwise direction with respect to the radial direction when viewed in the central axis direction of the combustion chamber 2 as shown in the plan sectional view of FIG. 7B. Thus, the combustion air guided from the upper air chamber 4 through the first swirling airflow pipe 71 is blown into the combustion chamber 2 in the eccentric direction of the central axis. The air supply pipe located on the bottom surface side of the combustion chamber 2 with respect to the first swirling air flow tube 71 has a side facing the combustion chamber 2 facing the bottom surface of the combustion chamber 2 with respect to a plane perpendicular to the central axis of the combustion chamber 2. And a downward airflow pipe 72 inclined. As shown in the longitudinal sectional view of FIG. 7A, the descending airflow pipe 72 is disposed at an inclination angle θ with respect to the direction perpendicular to the axis of the combustion chamber 2, and as shown in the plan sectional view of FIG. 7C. In addition, the combustion chamber 2 is arranged in the radial direction when viewed from the central axis direction. As a result, the combustion air guided from the upper air chamber 4 through the descending airflow pipe 72 is blown into the combustion chamber 2 toward the bottom surface. The air supply pipe located on the bottom side of the combustion chamber 2 with respect to the downflow pipe 72 is a second swirling airflow pipe 73 parallel to a plane perpendicular to the central axis of the combustion chamber 2. The second swirl airflow pipe 73 is disposed at an inclination angle β counterclockwise with respect to the radial direction when viewed in the central axis direction of the combustion chamber 2 as shown in the plan sectional view of FIG. 7D. . The inclination angle β with respect to the radial direction of the second swirl airflow tube 73 forms an angle opposite to the inclination angle α with respect to the radial direction of the first swirl airflow tube 71 with respect to the radial direction. Thus, the combustion air guided from the upper air chamber 4 through the second swirl airflow tube 73 is blown into the combustion chamber 2 in an eccentric direction opposite to the first swirl airflow tube 71 with respect to the central axis. Combustion air blown in the eccentric direction by the first swirl airflow tube 71, combustion air blown in the bottom direction by the descending airflow tube 72, and combustion air blown in the eccentric direction by the second swirl airflow tube 73 And a turbulent flow of combustion air is formed at the installation positions of the air supply pipes 71, 72, 73 of the combustion chamber 2.

  Here, the inclination angle α with respect to the radial direction of the first swirling airflow pipe 71 is greater than 0 ° and 50 ° or less, and preferably 1 ° or more and 30 ° or less. In addition, the inclination angle θ of the descending airflow pipe 72 with respect to the direction perpendicular to the axis is greater than 0 ° and 50 ° or less, and preferably 1 ° or more and 30 ° or less. Moreover, the inclination | tilt angle (beta) with respect to the radial direction of the 2nd turning airflow pipe 73 is larger than 0 degree and 50 degrees or less, Preferably, they are 1 degree or more and 30 degrees or less.

  As shown in the longitudinal sectional view of FIG. 7A, the air supply pipes 71, 72, 73 of the combustion chamber 2 have a first swirling airflow pipe 71 on the top surface side of the combustion chamber 2, and a downflow airflow pipe 72 at the central stage. In addition, the bottom surface side of the combustion chamber 2 is a second swirling airflow tube 73, and the top surface side of the combustion chamber 2 is a descending airflow tube 72 as shown in the longitudinal sectional view of FIG. The airflow pipe 71 and the bottom side of the combustion chamber 2 may be the ascending airflow pipe 74. The ascending air flow pipe 74 is inclined with respect to the plane perpendicular to the central axis of the combustion chamber 2, the side facing the combustion chamber 2 is inclined toward the top surface of the combustion chamber 2, and in the radial direction when viewed from the central axis direction of the combustion chamber 2. Be placed. The updraft pipe 74 blows the combustion air guided from the upper air chamber 4 through the downflow pipe 72 into the combustion chamber 2 in the top surface direction. Further, the number of installation stages of the swirl airflow pipe 71, the downflow airflow pipe 72, and the upflow airflow pipe 73 can be appropriately set according to the flow to be formed in the combustion chamber 2. The number of stages of the entire air supply pipes 71, 72, 73 may be any number other than three. Alternatively, all the stages may be formed by only the first or second swirl airflow pipes 71 and 73, and only the swirl flow may be formed in the combustion chamber 2.

  In addition, the secondary air supply unit may be formed using an air supply pipe whose inside is an air supply path, or may be provided with a through hole in a thick wall to form an air supply path. In this case, the extending direction of the through hole is inclined with respect to a plane perpendicular to the central axis of the combustion chamber 2 or a plane passing through the central axis, or an inclined passage or a swirl passage is formed in the radial direction. May be.

  FIG. 9 is a block diagram showing a control system of the boiler device 10. As shown in FIGS. 1 and 10, the boiler apparatus 10 includes the combustion furnace 1, a water heat exchanger 14 as a thermal device to which combustion gas is supplied from the combustion furnace 1, a water heat exchanger 14, and a combustion furnace. 1, a hot water storage tank 15 for storing high-temperature water heated in 1, a cyclone dust collector 17 that collects exhaust gas guided from the water heat exchanger 14, and an induction fan 18 that is connected to the exhaust port of the cyclone dust collector 17. Is provided.

  In the combustion furnace 1, wood chips as fuel are unwound from the supply conveyor 12 of the metering feeder 11 and supplied to the screw conveyor 9 through a shut-off valve 13 for maintaining the pressure in the combustion chamber 2. In the silo portion of the fixed amount feeder 11, a stirring device 114 is provided in which a plurality of stirring rods extending in the radial direction are fixed to a rotating shaft. The stirring device 114 is rotationally driven by a driving means 115 installed on a side portion of the fixed amount feeder 11 and stirs the fuel F stored in the silo portion of the constant amount feeder 11. The silo portion of the fixed amount feeder 11 is provided with a level sensor L1 for detecting the surface position of the fuel F to be stored and detecting the remaining amount. The screw conveyor 9 is provided with a temperature sensor T1, and based on the temperature detected by the temperature sensor T1, it is monitored whether the fuel F conveyed by the screw conveyor 9 is ignited by the high-temperature air from the combustion chamber 2. Yes. When the temperature sensor T1 detects an abnormal temperature and detects the ignition of the fuel F, the open / close valve V1 of the water supply pipe connected to the screw conveyor 9 is opened to extinguish the fire.

  An exhaust pipe 22 that guides combustion gas from the combustion chamber 2 of the combustion furnace 1 is connected to the water heat exchanger 14 and communicates with the start end of the combustion gas passage of the water heat exchanger 14. The temperature of the combustion gas sent from the combustion chamber 2 to the water heat exchanger 14 is detected by a gas temperature sensor T2 in the combustion chamber 2, and the supply amount of combustion air and fuel F is based on the detected value of the gas temperature sensor T2. Is controlled.

  FIG. 10 is a schematic cross-sectional view showing the water heat exchanger 14 in detail. In the water heat exchanger 14, the upper part of the vertically long casing 141 is partitioned by an upper partition plate 142 that also serves as a tube plate and a partition wall 144, and a front smoke chamber 145 and a rear smoke chamber 146 are formed. Further, the lower portion in the casing 141 is partitioned by a lower partition plate 143 that also serves as a tube plate, and an intermediate smoke chamber 147 is formed. A water can 149 is formed between the upper partition plate 142 and the lower partition plate 143 of the casing 141, and a plurality of smoke tubes 148, 148,... Whose ends are welded to the upper partition plate 142 and the lower partition plate 143. .. Are arranged inside the water can 149. In this water heat exchanger 14, the combustion gas that has flowed into the front smoke chamber 145 from the combustion furnace 1 flows into the smoke pipe 148 as indicated by the arrow G, and after exchanging heat with the water in the water can 149, the intermediate smoke chamber It flows to 147. The combustion gas turns back in the intermediate smoke chamber 147, flows into the smoke pipe 148 as indicated by an arrow H, and further exchanges heat with the water in the water can 149, and then flows into the rear smoke chamber 146. The combustion gas in the rear smoke chamber 146 is exhausted through the exhaust pipe 164 as indicated by an arrow I and received by the cyclone dust collector 17 on the downstream side. Water from the water jacket 3 of the combustion furnace 1 flows into the water can 149 as shown by an arrow W2 through a water supply port 160 provided at the lower portion of the casing 141. The water whose temperature has risen due to heat exchange with the combustion gas passing through the smoke pipes 148 and 149 in the water can 149 is provided in a communication pipe 161 communicating with the upper part of the water can 149, and the upper part of the communication pipe 161. The water is discharged through the drain 162 as shown by the arrow W3. At the upper end of the communication pipe 161, an atmospheric release valve 163 is provided for releasing water vapor to the atmosphere when the water vapor in the water can 149 reaches a predetermined pressure.

  The water heat exchanger 14 further heats the water heated by the water jacket 3 of the combustion furnace 1 and supplies it to the hot water storage tank 15. The water can 149 of the water heat exchanger 14 is provided with a water level sensor L3 that detects the amount of water inside. The drain pipe 32 of the water jacket 3 is provided with a temperature sensor T3 that detects the temperature of water. The hot water storage tank 15 is provided with a temperature sensor T4 for detecting the temperature of the stored water and a water level sensor L2 for detecting the amount of water inside.

  The hot water storage tank 15 is connected to a heating return pipe 81 extending from the water heat exchanger 14 and a heating feed pipe 33 interposed in the circulation pump 16 and extending to the water jacket 3 of the combustion furnace 1. The water heat exchanger 14, the water jacket 3 and the hot water storage tank 15 constitute a circulation path. Further, the hot water storage tank 15 includes a hot water storage tank 15, a water heat exchanger 14, a water supply pipe 151 that supplies water according to the water level in the water jacket 3, and hot water as a hot water supply facility as indicated by an arrow D. As shown by the arrow E, the hot water supply pipe 152 for supplying hot water is connected to the hot water supply return pipe 153 from which the hot water returns.

  The cyclone dust collecting device 17 includes a cylindrical portion 171 provided with a combustion gas suction port on a side surface, an inverted conical separating portion 172 that forms a swirling flow inside the cylindrical portion 171, and a cylindrical portion. 171 has an exhaust cylinder 175 that protrudes upward from the inside. A rotary valve 173 is connected to the lower end of the separation part 172, and a dust container 174 is provided via the rotary valve 173. The cyclone dust collector 17 sucks the combustion gas that has been heat exchanged by the water heat exchanger 14 from the suction port of the cylindrical portion 171, and the cylindrical portion 171 and the separation portion 172 cause the combustion gas to flow as indicated by an arrow Y 1. A swirl flow is formed, and dust contained in the combustion gas is separated by the centrifugal force of the swirl flow. The dust separated from the combustion gas is discharged from the rotary valve 173 to the dust container 174, while the combustion gas from which the dust is separated is discharged from the exhaust cylinder 175 as indicated by an arrow Y2. The combustion gas discharged to the exhaust cylinder 175 is sucked into the induction fan 18 through the exhaust pipe 176 connected to the exhaust cylinder 175.

  The induction fan 18 is formed of a centrifugal blower, and a fan casing that houses an intake pipe 181 connected to an exhaust pipe 176 connected from a cyclone dust collector 17 and a rotor blade disposed concentrically with the central axis of the intake pipe 181. 182 and a drive unit 183 that drives the rotor blades in the fan casing 182. A chimney 19 extending in the vertical direction is connected to an exhaust port provided in a side portion of the fan casing 182.

  The boiler device 10 includes a supply conveyor 12, a shutoff valve 13, a screw conveyor 9, based on detection information of the level sensor L1, temperature sensor T1, gas temperature sensor T2, water level sensors L2 and L3, and temperature sensors T3 and T4. A control unit 25 that controls the operation of the opening / closing valve V1, the induction fan 18, the blower 20, and the circulation pump 16 is provided. With this control unit 25, the amount of heat generated in the combustion chamber 2, the water jacket 3 and the water heat exchanger 14 so that the temperature of the hot water storage tank 15 becomes a predetermined temperature and the water level of the hot water storage tank 15 becomes a predetermined water level. And the circulation amount of water in the hot water storage tank 15 is controlled.

  The combustion furnace 1 and the boiler device 10 having the above-described configuration operate as follows. First, the water level in the water heat exchanger 14 and the hot water storage tank 15 is confirmed based on the detection information of the water level sensors L2 and L3. When the water level in the water heat exchanger 14 and the hot water storage tank 15 is lower than the reference value, water is supplied to the hot water storage tank 15 through the water supply pipe 151 as indicated by an arrow C. Note that the amount of water supplied to the hot water storage tank 15 through the water supply pipe 151 may be adjusted by a ball tap having a floating ball. When the water levels in the water heat exchanger 14 and the hot water storage tank 15 satisfy the reference values, the induction fan 18 and the blower 20 are started, and the shutoff valve 13 is opened to start the supply conveyor 12 and the screw conveyor 9. The blower 20 is activated to supply combustion air to the upper air chamber 4 through the upper air supply pipe 42 and supply combustion air to the lower air chamber 5 through the lower air supply pipe 52. The shutoff valve 13 is opened, the feed conveyor 12 and the screw conveyor 9 are started, the wood chips of the fuel F are unwound from the fixed quantity feeder 11 by the feed conveyor 12, and pass through the shutoff valve 13 to the combustion chamber 2 by the screw conveyor 9. Fuel F is charged.

  In the combustion furnace 1, the combustion air supplied to the upper air chamber 4 is supplied to the combustion chamber through the air supply pipes 71, 72 and 73. At this time, the combustion air blown out from the first swirl airflow pipe 71 in the eccentric direction of the central axis of the combustion chamber 2, the combustion air blown out from the downflow airflow pipe 72 to the bottom surface side, and the center of the combustion chamber 2 from the second swirl airflow pipe 73. Combustion air blown in the eccentric direction opposite to the first swirling airflow pipe 71 is mixed in the eccentric direction of the shaft, and a turbulent flow of combustion air is generated in the lower portion of the combustion chamber 2. From the fuel supply port 91a located at the lower part of the region where the turbulent flow is formed, the fuel F supplied by the screw conveyor 9 is input into the combustion chamber 2 as indicated by an arrow F1, and the injected fuel F is It is held on the bottom plate 6 of the combustion chamber 2.

  The fuel F held on the bottom plate 6 is ignited by a burner (not shown) that operates with petroleum fuel, and is supplied from the lower air chamber 5 through the through holes 61, 61,. Combustion is started by receiving air and secondary combustion air supplied from the upper air chamber 4 through the air supply pipes 71, 72 and 73. The combustion gas generated with the combustion of the fuel F flows in a swirling manner above the region in the combustion chamber 2 where the turbulent flow is generated. The fuel F is sufficiently supplied with combustion air through the through holes 61 and the air supply pipes 71, 72, 73 in the process in which the combustion gas accompanying combustion flows in the combustion chamber 2 while forming a turbulent flow and a swirling flow, Moreover, since it is heated over a relatively long time, complete combustion is performed. Accordingly, a stable amount of heat can be obtained while using the fuel F, which is a plant-based regenerated fuel. Combustion gas generated by combustion in the combustion chamber 2 is sent to the water heat exchanger 14 through the exhaust pipe 22.

  The combustion gas sent to the water heat exchanger 14 is introduced into the front smoke chamber 145 of the water heat exchanger 14 through the exhaust pipe 22 and exchanges heat with the water in the water can 149 while passing through the smoke pipes 148 and 149. . The combustion gas that has reached the rear smoke chamber 146 is guided to the cyclone dust collector 17. In the cyclone dust collecting device 17, the combustion gas flowing in from the suction port of the cylindrical portion 171 is guided to the separation portion 172, and dust is separated by centrifugal force when flowing in the separation portion 172 in a swirling manner. The dust separated from the combustion gas is collected in a dust container 174 below the cyclone dust collector 17. The combustion gas from which the dust has been separated passes through the exhaust pipe 175, is sucked into the induction fan 18 through the exhaust pipe 176 connected to the exhaust tower 175, and is exhausted through the chimney 19. A bag filter for removing fine particles contained in the combustion gas may be connected to the downstream side of the attracting fan 18.

  The water in the hot water storage tank 15 is sent to the water jacket 3 of the combustion furnace 1 through the heating feed pipe 33 by the circulation pump 16. The water heated by receiving heat transmitted from the combustion chamber 2 in the water jacket 3 is guided to the water can 149 of the water heat exchanger 14 through the drain pipe 32 and exchanges heat with the combustion gas in the water heat exchanger 14. And then heated further. The water heated by the water heat exchanger 14 is returned to the hot water storage tank 15 through the heating return pipe 81.

  The control unit 25 controls the operation of the supply conveyor 12, the shutoff valve 13 and the screw conveyor 9 based on the temperature of the water in the hot water storage tank 15 detected by the temperature sensor T4, and the amount of fuel F supplied to the combustion chamber 2 And the operations of the induction fan 18 and the blower 20 are controlled to control the amount of combustion air supplied to the combustion chamber 2. When the water temperature of the hot water storage tank 15 is lowered due to the addition of the low temperature water from the water supply pipe 151 as the water of the hot water storage tank 15 is consumed by the use facility, the control unit 25 increases the temperature of the water of the hot water storage tank 15. Control the combustion mode. That is, the shutoff valve 13 is opened, the supply amount of the fuel F by the supply conveyor 12 and the screw conveyor 9 is increased, and the supply amount of the combustion air to the combustion chamber 2 is increased by increasing the supply amount of the blower 20. In addition, the suction amount of the attracting fan 18 is increased to increase the amount of combustion gas sucked from the water heat exchanger 14 of the cyclone dust collector 17. Furthermore, the amount of water sent to the circulation pump 16 is increased, and the amount of water sent to the water jacket 3 and the water heat exchanger 14 is increased. As a result, the amount of heat generated by burning the fuel F in the combustion chamber 2 increases, the amount of water heated by the water jacket 3 and the water heat exchanger 14 increases, and the water temperature of the hot water storage tank 15 rises. When the water in the hot water storage tank 15 reaches a predetermined temperature, the control unit 25 reduces the amount of fuel F supplied by the supply conveyor 12 and the screw conveyor 9 and decreases the amount of air blown by the blower 20 to burn into the combustion chamber 2. The supply amount of air is decreased, the suction amount of the induction fan 18 is decreased, the amount of combustion gas sucked from the water heat exchanger 14 is decreased, and the water supply amount of the circulation pump 16 is decreased. When the supply of the fuel F from the supply conveyor 12 to the screw conveyor 9 is stopped, the shutoff valve 13 is closed to prevent the backflow of combustion gas and combustion air from the combustion chamber 2.

  When the water heating operation by the water heat exchanger 14 is stopped due to the stop of the use of hot water or the like, the control unit 25 stops the control of the combustion mode and controls the standby mode. That is, the fuel supply amount by the supply conveyor 12 and the screw conveyor 9 is made smaller than that in the combustion mode, and the suction amount of the attracting fan 18 and the blower 20 are made smaller than those in the combustion mode. Further, water supply to the water heat exchanger 14 by the circulation pump 16 is stopped. As a result, in the state where the supply of heat to the water heat exchanger 14 is substantially stopped, the combustion chamber 2 holds the seed fire. In this way, the minimum amount of fuel F is held in the receiving portion 62 of the bottom plate 6 facing the combustion chamber 2, and the use of warm water is resumed by leaving the fuel F to leave a seed flame. If the amount of fuel supplied by the supply conveyor 12 and the screw conveyor 9 and the amount of air blown from the blower 20 are increased when operation is required, the amount of heat generated in the combustion chamber 2 can be quickly recovered by quickly igniting the fuel F. can do. That is, it is possible to quickly move from the standby mode to the combustion mode, and to quickly respond to the demand for hot water. In the standby mode, the supply of the fuel F by the supply conveyor 12 and the screw conveyor 9 may be performed continuously or intermittently. In short, it suffices if fuel F can be supplied to the extent that it can hold the seed fire.

  In the above embodiment, the fuel F made of wood chips is used as the plant-based regenerated fuel. However, a regenerated fuel obtained by molding a plant-based material, such as a wood pellet, may be used. Plant-based materials include wood-based materials such as sawdust, wood chips, thinning and pruning materials, agricultural materials such as rice straw, rice husks, weeds and bagasse, waste-based materials such as construction waste, and waste paper And paper-based materials such as waste pulp. Further, the plant-based regenerated fuel may be a fuel partially using a plant-based material, for example, RPF.

  Moreover, in the said embodiment, although the combustion furnace 1 supplied heat to the water heat exchanger 14 as a thermal equipment, you may supply heat to another thermal equipment. Further, the combustion furnace 1 includes the water jacket 3 on the outer peripheral side of the combustion chamber 2, but the water jacket 3 may not be provided.

DESCRIPTION OF SYMBOLS 1 Combustion furnace 2 Combustion chamber 6 Bottom plate 7 Air supply pipe 9 Screw conveyor 61 Through-hole 62 Receiving part F Fuel

Claims (7)

A combustion furnace for burning plant regenerated fuel,
A cylindrical combustion chamber;
A fuel supply section for supplying fuel into the combustion chamber from a side surface of the combustion chamber;
A primary air supply for supplying combustion air from the bottom of the combustion chamber;
A secondary air supply for supplying combustion air from the side of the combustion chamber;
A receiving portion provided on a bottom surface of the combustion chamber and receiving fuel supplied from the fuel supply portion;
The primary air supply unit has a plurality of holes provided in the bottom surface of the combustion chamber,
The secondary air supply unit is formed in a plane including the center axis of the upper Symbol combustion chamber, a first air supply passage facing direction inclined to the radial direction of the combustion chamber, a central axis perpendicular to the combustion chamber A second air supply path parallel to the surface, and forms a swirling flow of combustion air in the combustion chamber, and blows out from the first air supply path in a direction inclined to the bottom surface side or the top surface side of the combustion chamber. A combustion furnace characterized in that a turbulent flow is formed by mixing the generated combustion air with the combustion air flowing in the other direction. A combustion furnace for burning plant regenerated fuel,
A cylindrical combustion chamber;
A fuel supply section for supplying fuel into the combustion chamber from a side surface of the combustion chamber;
A primary air supply for supplying combustion air from the bottom of the combustion chamber;
A secondary air supply for supplying combustion air from the side of the combustion chamber;
A receiving portion provided on a bottom surface of the combustion chamber and receiving fuel supplied from the fuel supply portion;
The primary air supply unit has a plurality of holes provided in the bottom surface of the combustion chamber,
The secondary air supply unit has a first air supply path facing in a direction inclined with respect to the radial direction of the combustion chamber in a plane including the central axis of the combustion chamber, and the swirl flow of the combustion air in the combustion chamber And form turbulent flow,
A combustion furnace comprising a bottom plate having the hole formed in the entire surface in a plan view on a bottom surface of the combustion chamber, and an opening / closing mechanism for opening and closing the hole in a central portion of the bottom plate. In the combustion furnace according to claim 1 or 2,
The fuel supply unit includes a screw conveyor disposed to be inclined with respect to the central axis of the combustion chamber, and a fuel supply port that communicates with an end of the screw conveyor and opens to a side surface of the combustion chamber. Combustion furnace. In the combustion furnace according to claim 3,
The secondary air supply unit has a plurality of combustion air outlets that open to the side of the combustion chamber,
A combustion furnace characterized in that at least a part of the plurality of outlets of the secondary air supply unit is disposed farther from the bottom surface of the combustion chamber than the fuel supply port of the fuel supply unit. In the combustion furnace according to claim 1 or 2,
The combustion furnace according to claim 1, wherein the secondary air supply section includes a third air supply path that faces in a direction inclined with respect to a radial direction of the combustion chamber in a plane perpendicular to the central axis of the combustion chamber. In the combustion furnace according to claim 1 or 2,
A control unit that controls the fuel supply unit and a blower that supplies combustion air to the combustion chamber;
The control unit controls a fuel supply amount by the fuel supply unit and a blown amount by the blower to adjust a heat amount to be generated in the combustion chamber, a fuel supply amount by the fuel supply unit, and the blower A combustion furnace characterized by having a standby mode in which the amount of air blown by is controlled to a smaller amount than in the combustion mode, and a seed fire is held in the combustion chamber. The combustion furnace according to claim 2,
A control unit for controlling the fuel supply unit, a blower for supplying combustion air to the combustion chamber, and the opening and closing mechanism;
The control unit controls the fuel supply amount by the fuel supply unit, the air supply amount by the blower, and the opening / closing state of the hole in the bottom plate by the opening / closing mechanism,
A combustion mode for adjusting the amount of heat to be generated in the combustion chamber with all the holes in the bottom plate opened,
With the hole at the center of the bottom plate closed, the amount of fuel supplied by the fuel supply unit and the amount of air blown by the blower are controlled to be less than in the combustion mode, and seeds are placed at the center of the bottom plate. And a standby mode for holding a fire.

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