JP4989287B2 - Wood pellet combustor and operation method thereof - Google Patents

Description

  The present invention relates to a wood pellet combustor and an operation method thereof.

  In a conventional wood fuel heating device (for example, see Patent Document 1), the content rate of bark components used in wood solid fuel (wood pellets) is judged, and the optimum fuel supply amount and air supply amount for combustion are determined. By adjusting, the generation of clinker (solidified combustion residue such as ash and soot) is suppressed.

  However, since the above-described wood fuel heating device requires an optical property measuring device for measuring the optical properties of the surface of the wood solid fuel, the overall configuration of the device is complicated.

  On the other hand, a pellet stove that pulverizes clinker stuck to a combustion dish by rotating blades attached to a combustion dish that burns wood pellets has been devised (see, for example, Patent Document 2).

However, the above-described pellet stove also requires a motor for rotating the blades, so that the overall configuration of the apparatus is complicated.
JP-A-2005-257121 JP 2005-201575 A

  In view of the above facts, an object of the present invention is to obtain a wood pellet combustor capable of suppressing the generation of clinker with a simple configuration and an operating method thereof.

A wood pellet combustor according to the invention described in claim 1 is a combustion section for burning wood pellets, a fuel supply device for supplying wood pellets to the combustion section, a blower for supplying air to the combustion section, controls work movement of the fuel supply device and the blower, the combustion section by reducing the wood pellets supply to the combustion section by the fuel supply device while increasing the amount of air supplied to the combustion unit by the blower It is characterized by having a control unit which Ru is periodically promoting combustion of wood pellets periodically to excess air state.

The “excessive air state” according to claim 1 refers to a state in which a larger amount of air is supplied to the combustion unit than is necessary for optimally burning the wood pellets supplied to the combustion unit. . This also applies to claim 3 described below.

In addition, in the first aspect of the present invention, “periodically setting the excess air state” means that at least one of the time when the air is excessive and the time when the air is not excessive is set in addition to the case where the air is excessive at regular intervals. Including the case where it is not constant (changes periodically). This also applies to claim 3 described below.

In wood pellet combustor according to claim 1, a control device for controlling the work movement of the fuel supply device and the blower, wood pellets to the combustion section by the fuel supply device while increasing the amount of air supplied to the combustion unit by the blower By reducing the supply amount, the combustion section is periodically brought into an excess air state. Thereby, since combustion of the wood pellet in a combustion part is periodically accelerated | stimulated, the combustion residue which became the clinker in the combustion part can be made into ash. Therefore, the generation of clinker can be suppressed with a simple configuration.

A wood pellet combustor according to a second aspect of the present invention is the wood pellet combustor according to the first aspect, wherein the control device includes a cycle setting dial for arbitrarily changing the cycle of the excess air state. the operating time setting dial for arbitrarily changing the duration of the excess air state is characterized that it is connected.

In the operation method of the wood pellet combustor which concerns on invention of Claim 3 , the combustion part which burns a wood pellet, the fuel supply apparatus which supplies a wood pellet to the said combustion part, and the air blower which supplies air to the said combustion part When, a wood pellet burner operating method having a by the fuel supply device and controls the operation of the blower, the fuel supply device while increasing the amount of air supplied to the combustion unit by the blower and to the combustion section periodically to excess air condition characterized by Rukoto combustion periodically to promote the wood pellets by reducing the wood pellets supply to the combustion section.

The wood pellet burner operating method according to claim 3, by controlling the work movement of the fuel supply device and the blower, wood to the combustion section by the fuel supply device while increasing the amount of air supplied to the combustion unit by the blower By reducing the pellet supply amount, the combustion section is periodically brought into an excess air state. Thereby, since combustion of the wood pellet in a combustion part is periodically accelerated | stimulated, the combustion residue which became the clinker in the combustion part can be made into ash. Therefore, the generation of clinker can be suppressed with a simple configuration.

  As described above, in the wood pellet combustor and the operation method thereof according to the present invention, generation of clinker can be suppressed with a simple configuration.

  FIG. 1 is a side sectional view showing a configuration of a pellet stove 10 as a wood pellet combustor according to an embodiment of the present invention. 2 shows a cross-sectional view taken along line 2-2 of FIG.

  The pellet stove 10 includes a housing 12. A hopper 16 serving as a fuel tank is disposed inside the housing 12. Inside the hopper 16 is stored a wood pellet 14 which is a wood solid fuel made by pulverizing and compressing thinned wood. In the present embodiment, the wood pellet 14 is processed and formed into, for example, a cylindrical shape, and has a diameter of about 4 mm to 5 mm and a length of about 5 mm to 6 mm.

  A fuel supply device 18 (fuel transfer device) is provided below the hopper 16. The fuel supply device 18 has an upper screw 20 and a lower screw 22 that are arranged in two different levels. The upper screw 20 and the lower screw 22 are rotated by the power of the motor 24. The motor 24 is connected to the control device 38 via a wiring (not shown) disposed in the pellet stove 10.

  Further, a fuel lowering port 26 is formed in the lower part of the hopper 16, and the wood pellets 14 put into the hopper 16 are scraped out from the fuel lowering port 26 by the upper screw 20 and conveyed to the chute 28. Fall. The wood pellets 14 that have fallen from the chute 28 are pushed out toward the combustion chamber 30 by the lower screw 22 disposed in the lower stage of the fuel supply device 18. The combustion chamber 30 is provided with a flat plate-like rooster 32 as a combustion shelf constituting a combustion section, and the wood pellets 14 pushed out toward the combustion chamber 30 are supplied to the upper surface of the rooster 32 (FIG. 1). Arrow A).

  As shown in FIG. 3, a rod-shaped ignition heater 34 is provided below the rooster 32. The ignition heater 34 is a so-called “ceramic heater” and is arranged in a state inclined at a predetermined angle with respect to the plate surface of the rooster 32. The ignition heater 34 is fixed to the lower surface of the rooster 32 with a stay 35 fixed to the lower surface of the rooster 32 with screws and a nut 37.

  The tip of the ignition heater 34 is inserted through a through hole 36 formed in the rooster 32 and protrudes from the upper surface of the rooster 32 by a predetermined amount. For this reason, when the wood pellet 14 is supplied to the upper surface of the rooster 32 as described above, the tip of the ignition heater 34 is covered with the wood pellet 14. The ignition heater 34 is connected to a control device 38 via a wiring (not shown) disposed in the pellet stove 10.

  On the other hand, a plurality of vent holes 40 are formed in the rooster 32, and travels in the direction of arrow B in FIG. 1 from the blower 42 installed below the fuel supply device 18 and is sent to the air intake chamber 44. The air (primary air) passes through the vent hole 40 and is supplied (blowed) to the upper side of the rooster 32. The blower 42 is connected to the control device 38 via a wiring (not shown) disposed in the pellet stove 10.

  Further, the air sent from the blower 42 also flows into the air passage 46 (see arrow C in FIG. 1), and is ejected from the air hole 50 formed in the partition plate 48 into the combustion chamber 30 (2 Next air). Further, the air that has flowed into the air passage 46 also flows into the air return passage 52 branched to the fuel supply device 18 side, and is ejected from above the chute 28 of the fuel supply device 18.

  Here, in the present pellet stove 10, the motor 24, the ignition heater 34, and the blower 42 of the fuel supply device 18 described above are centrally controlled by the control device 38. The control device 38 includes a CPU and a driver. When a power switch (not shown) mounted on the pellet stove 10 is turned “ON”, the motor 24 and the blower 42 of the fuel supply device 18 are operated. The ignition heater 34 is energized for a predetermined time.

   When the ignition heater 34 generates heat by energization, the wood pellet 14 covering the tip of the ignition heater 34 is heated and ignited. At this time, as described above, the primary air (see arrow B in FIG. 1) sent from the blower 42 to the air intake chamber 44 passes through the vent hole 40 of the rooster 32 and is ventilated to the combustion chamber 30. The wood pellet 14 supplied (conveyed) to the upper surface of 32 is burned. When the wood pellets 14 on the upper surface of the rooster 32 are burning, the wood pellets 14 in the hopper 16 are replenished and burned on the rooster 32 sequentially by the upper screw 20 and the lower screw 22 of the fuel supply device 18.

  On the opposite side of the rooster 32 from the fuel supply device 18, a large ash tray 58 is disposed, and the burned residue (ash) of the burned wood pellet 14 is newly lost by the upper screw 20 and the lower screw 22. It is pushed out by the wood pellets 14 that are replenished on 32 and falls into the ash tray 58.

  It should be noted that the wood pellet 14 does not become a powder form even if burned out, and becomes ash with a little of the original shape, so that a little ash falls from the vent hole 40 of the rooster 32 but the air below the rooster 32 The intake chamber 44 is provided with an ash tray small 60, and the ash of the wood pellet 14 that has fallen into the air intake chamber 44 from the vent hole 40 of the rooster 32 falls into the ash tray small 60. Yes.

  On the other hand, the combustion of the wood pellets 14 may cause the combustion chamber 30 to be filled with combustible gas and inhibit the combustion of the wood pellets 14, but the air is supplied from the blower 42, and from the air hole 50 of the partition plate 48. Combustion of the dry-distillable combustible gas is promoted by the above-described secondary air ejected into the combustion chamber 30.

  Note that the air supplied from the blower 42 and ejected from above the chute 28 of the fuel supply device 18 through the air passage 46 and the air return passage 52 is the exhaust gas generated in the combustion chamber 30 and the fuel supply device 18. Prevent backflow to the side.

  A cylindrical flue 62 is provided on the upper surface of the housing 12 above the combustion chamber 30, and a baffle plate 64 is disposed inside the combustion chamber 30 below the flue 62. It is fixed to the wall. A plurality of ventilation holes 66 are formed in the baffle plate 64, and the exhaust gas generated in the combustion chamber 30 by the combustion of the wood pellets 14 is in the cylinders of the ventilation holes 66 and the flue 62 of the baffle plate 64. And is discharged from the exhaust pipe (not shown) connected to the flue 62 to the outside of the pellet stove 10 (see arrow D in FIG. 1).

  On the other hand, a thermostat 56 for detecting the temperature in the combustion chamber 30 is fixed to the partition plate 54 between the air passage 46 and the hopper 16. The thermostat 56 is connected to the control device 38 via a wiring (not shown) disposed on the pellet stove 10. The control device 38 detects the temperature of the combustion chamber 30 based on the detection result of the thermostat 56 and controls the operation of the fuel supply device 18 and the blower 42 based on the detection result.

  Further, the control device 38 controls the rooster 32 by the fuel supply device 18 in accordance with the operation state of a temperature control switch (not shown) mounted on the pellet stove 10 (for example, any one of weak, medium and strong is selected). The supply amount of wood pellets 14 (hereinafter referred to as fuel supply amount) is increased or decreased, and the supply amount of primary air (combustion air) to the rooster 32 by the blower 42 is increased or decreased according to the fuel supply amount. . Thereby, the control apparatus 38 supplies the optimal quantity of air to the upper surface side of the rooster 32 in order to burn the wood pellet 14 supplied to the upper surface of the rooster 32 at the time of normal driving | operation.

  Further, during the normal operation as described above, the control device 38 periodically changes the balance between the fuel supply amount and the air supply amount to the rooster 32 so that the upper surface side of the rooster 32 is periodically in an excessive air state ( In this state, a larger amount of air than the amount of air necessary for optimally burning the wood pellets 14 supplied to the upper surface of the rooster 32 is supplied to the upper surface side of the rooster 32.

  Note that a cycle setting dial (not shown) mounted on the pellet stove 10 is electrically connected to the control device 38, and by operating the cycle setting dial, the above-described cycle (hereinafter referred to as set time 1). Can be changed arbitrarily. In addition, an operating time setting dial (not shown) mounted on the pellet stove 10 is electrically connected to the control device 38. By operating the operating time setting dial, the duration time of the above-described excessive air state (hereinafter referred to as the “air excessive state”) , Set time 2) can be arbitrarily changed.

  Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG.

  In the pellet stove 10 configured as described above, the control device 38 starts normal operation when a power switch (not shown) mounted on the pellet stove 10 is operated to “ON” (step 100). In this step 100, the control device 38 ignites the wood pellets 14 on the upper surface of the rooster 32 by the ignition heater 34 and controls the operation of the fuel supply device 18 and the blower 42 to burn the wood pellets 14 in an optimum state. . When the processing at step 100 is completed, the routine proceeds to step 102.

  In step 102, the control device 38 determines whether or not a predetermined set time 1 (for example, 2 hours) has elapsed since the start of normal operation. If the determination in step 102 is negative, the control device 38 returns to step 100 and continues normal operation.

  On the other hand, if the determination in step 102 is affirmed, the process proceeds to step 104. In step 104, the control device 38 increases the amount of air supplied to the rooster 32 by the blower 42 and decreases the amount of fuel supplied to the rooster 32 by the fuel supply device 18. For this reason, the upper surface side of the rooster 32 becomes an air excess state, and combustion of the wood pellet 14 is accelerated | stimulated. In this case, the control device 38 adjusts the air volume of the blower 42 so that the wood pellet 14 does not disappear due to an excessive air supply amount. When the processing in step 104 is completed, the routine proceeds to step 106.

  In step 106, the control device 38 determines whether or not a predetermined set time 2 (for example, 20 minutes to 30 minutes) has elapsed since the processing in step 104 was started. If the determination in step 106 is negative, the control device 38 returns to step 104 and maintains the excess air state.

  On the other hand, if the determination in step 106 is affirmed, the control device 38 returns to step 100 and repeats the processing as described above.

  Thus, in this pellet stove 10, the control apparatus 38 makes the upper surface side of the rooster 32 (combustion part) an excess air state for every fixed time, and promotes the combustion of the wood pellet 14. FIG. For this reason, generation of clinker on the upper surface of the rooster 32 is suppressed.

  That is, when the amount of ash on the upper surface of the rooster 32 is increased by burning the wood pellets 14 for a long time, the silicon oxide component contained in the ash may be transformed into a glassy substance called clinker. In particular, the wood pellets 14 using the bark of the tree contain more ash components than the wood pellets 14 using the core of the tree, so that the amount of ash produced when burned increases, and the amount of clinker generated. Will also increase. Such a clinker induces ash accumulation on the rooster 32 and may block the supply of combustion air by closing the vent hole 40, which makes long-term stable combustion difficult.

  In this respect, in the present pellet stove 10, the upper surface side of the rooster 32 is brought into an air excess state every predetermined time as described above, so that the combustion residue of the wood pellet 14 that has become a clinker on the upper surface of the rooster 32 promotes combustion. To become ash. Therefore, generation | occurrence | production of a clinker can be suppressed, and even when a clinker generate | occur | produces, it can prevent that this clinker enlarges.

  In addition, in the pellet stove 10, when the control device 38 places the upper surface side of the rooster 32 in an excess air state, the air supply amount (air blowing amount) to the rooster 32 is increased. For this reason, since the ash on the upper surface of the rooster 32 is blown away, the ash is suppressed from staying on the upper surface of the rooster 32. Therefore, the occurrence of clinker can be suppressed also by this, and the combustion state of the wood pellet 14 can be stabilized by cleaning the upper surface of the rooster 32.

  Furthermore, in this pellet stove 10, when the control device 38 makes the upper surface side of the rooster 32 in an excess air state, the amount of fuel supplied to the rooster 32 is reduced. For this reason, it can suppress that the temperature (combustion chamber 30 temperature) of a combustion part becomes high too much because the wood pellet 14 is accelerated | stimulated combustion.

  As described above, in the pellet stove 10 according to the present embodiment, the generation of clinker is suppressed by a simple control method (operation method) that only periodically causes the upper surface side of the rooster 32 to be in an excess air state. For this reason, generation | occurrence | production of a clinker can be suppressed with a simple and cheap structure, and the whole structure of an apparatus does not enlarge.

  As described above, the wood pellet 14 using the bark of the tree has a larger amount of ash generated (amount of clinker generated), so the set time 2 in step 106 is set longer (for example, about 30 minutes). It is preferable to do. Moreover, since the wood pellet 14 using the core part of a tree has little generation | occurrence | production of ash, it is preferable to set the setting time 2 in step 106 short (for example, about 20 minutes).

  Furthermore, in the said embodiment, although the rooster 32 as a combustion part was made into the structure formed in flat form, this invention is not restricted to this, The shape of a combustion part can be set and changed suitably, for example, You may make it the structure by which the combustion part was formed in dish shape.

  Moreover, although the said embodiment demonstrated the case where this invention was applied with respect to the pellet stove which uses a wood pellet as a fuel, this invention can be applied also to the boiler etc. which use a wood pellet as a fuel. it can.

It is a sectional side view which shows the structure of the pellet stove concerning embodiment of this invention. FIG. 2 is a sectional view taken along line 2-2 of FIG. It is the expanded sectional view which expanded a part of FIG. It is a flowchart which shows the control procedure of the control apparatus which comprises the pellet stove which concerns on embodiment of this invention.

Explanation of symbols

10 Pellet stove (wood pellet combustor)
18 Fuel supply system 32 Rooster (combustion part)
42 Blower

Claims (3)

A combustion section for burning wood pellets;
A fuel supply device for supplying wood pellets to the combustion section;
A blower for supplying air to the combustion section;
The combustion by the fuel supply system and controls the work movement of the blower reduces the wood pellets supply to the combustion section by the fuel supply device while increasing the amount of air supplied to the combustion unit by the blower a controller Ru is periodically promoting combustion of wood pellets in the periodic excess air state section,
With wood pellet combustor. The said control device, and the cycle setting dial for arbitrarily changing the period of the excess air state, and operation time setting dial for arbitrarily changing the duration of the excess air state that it is connected The wood pellet combustor according to claim 1, wherein A combustion section for burning wood pellets;
A fuel supply device for supplying wood pellets to the combustion section;
A blower for supplying air to the combustion section;
A method for operating a wood pellet combustor comprising:
Controlling the operation of the fuel supply device and the blower, and reducing the amount of wood pellets supplied to the combustion portion by the fuel supply device while increasing the amount of air supply to the combustion portion by the blower. A method of operating a wood pellet combustor, wherein the combustion of wood pellets is periodically promoted by periodically making the air excessive.

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