JP5915873B2 - Hot air generator - Google Patents

Description

  The present invention relates to a warm air generator for heating the inside of an agricultural greenhouse, etc., in particular, solidified wood pellets or livestock excreta made by compressing and molding thinned wood or bark. The present invention relates to a hot air generator equipped with a combustion furnace using biomass as fuel.

  In recent years, due to environmental problems such as global warming, from the viewpoint of effective use of biomass resources, for example, heating using pelletized solid fuel (hereinafter simply referred to as wood pellets) obtained by compressing and molding thinned wood Combustion devices such as aircraft have been reviewed.

  Wood pellets are obtained by pulverizing and compressing dry wood. By pelletizing wood, there is an advantage that the shape is fixed and handling as a fuel becomes easy. For example, Patent Document 1 discloses a related art related to a hot air generator using such wood pellets as fuel. In Patent Document 1, in a system for heating a greenhouse for horticulture, a gas generator that carbonizes wood fuel to generate carbon monoxide gas, and a greenhouse using the carbon monoxide gas generated by the gas generator. There has been proposed a heating means that is provided with a heating means and that uses inexpensive wood fuel such as thinned wood to reduce the heating cost.

  However, in the apparatus of Patent Document 1, when burning whole wood pellets or bark-based pellets (hereinafter referred to as bark pellets), the ash generated with the combustion is melted, and unburned matter or vitrified fuel residue (so-called , Clinker) is generated, causing incomplete combustion, and continuous combustion is hindered. In particular, when bark pellets are used, the ash content of the fuel itself is greater than that of the wood part pellets, so it is necessary to more effectively discharge the ash deposited in the combustion chamber.

  Thus, when whole-wood pellets or bark-type pellets are burned in the combustion chamber, the ash generated with the combustion is melted, clinker is generated, incomplete combustion is caused, and continuous combustion is inhibited. In particular, in a pellet containing a lot of bark, clinker formation was inevitable.

  For this reason, a combustion apparatus that combusts solid fuel such as wood pellets on a combustion dish provided in the combustion chamber has been proposed (see, for example, Patent Document 2). In this combustion apparatus, the solid fuel is in the center of the combustion dish. A rotating ring that holds the solid fuel on the outer peripheral portion of the combustion dish is configured such that the solid fuel that is being burned is moved to the outer peripheral side of the combustion dish by the newly supplied solid fuel. Is attached. A gap is formed between the rotating ring and the combustion dish. When the rotating ring rotates with respect to the combustion dish, solid fuel ash and clinker burned on the combustion dish are discharged from the gap. It has become.

  However, when the gap is large, the solid fuel before complete combustion is discharged. On the other hand, when the gap is small, there is a problem that ash and clinker are not discharged well.

  Accordingly, the solid fuel is supplied to the central portion, and the supplied solid fuel is moved to the outer peripheral side, and the supplied solid fuel is burned while being moved to the outer peripheral side, and the outer periphery of the combustion tray A holding member provided with a fuel discharge port in part and an opening / closing means for opening and closing the fuel discharge port, and the fuel discharge port of the holding member provided on the outer peripheral portion of the combustion dish is an opening / closing means The solid fuel moved to the outer periphery of the combustion dish is held by the holding member, burned well on the combustion dish to become ash, and the fuel discharge port of the holding member by the opening / closing means When the is opened, the combustion device (see Patent Document 3), which can discharge solid fuel ash and clinker well from the fuel outlet, periodically balance the fuel supply amount to the rooster and the air supply amount To change By making the upper surface of the rooster into an excess of air at regular intervals, the combustion residue of the wood pellets that became clinker on the upper surface of the rooster is promoted to become ash and suppress the generation of clinker A pellet stove that can be used (wood pellet combustor) has been proposed (see Patent Document 4).

JP 2008-104382 A JP 2004-293828 A JP 2007-107845 A JP 2008-267709 A

  The present inventors have also made the present invention to further improve the combustion efficiency of biomass pellets after intensive studies. That is, the present invention is a temperature that can suppress the accumulation of ash and the generation of clinker on the hearth of a combustion furnace using biomass pellets as fuel and continuously and stably burn the biomass pellets to improve the combustion state. An object is to provide a wind generator.

  For this reason, the present invention arranges a combustion furnace for burning biomass-derived solid fuel and a combustion dish that rotates the combustion furnace in the horizontal direction, and heats the air supplied from the outside in the combustion furnace. In the hot air generator for generating wind, the combustion dish is formed in a truncated cone shape having a high central part and a low outer peripheral part, and an air blowing hole for discharging combustion air penetrates below the combustion dish. It is arranged along the radial direction of the hearth surface of the combustion furnace to which the solid fuel to be supplied is burned by supplying the air discharged outward from the air blowing holes to the combustion dish and the surrounding fuel. The first feature is that a scraper for agitating the solid fuel during combustion and crushing the clinker during production is provided. A second feature of the scraper is that it has a protrusion protruding in a high temperature range of 1100 to 1250 ° C. of the combustion bed. Furthermore, the combustion dish has a third feature in that it includes a hole-shaped opening through which the solid fuel pushed up from the fuel transport section passes. Still further, a fourth feature is that the combustion dish and the scraper rotate relatively.

The device according to the present invention has the following excellent effects.
(1) The supplied solid fuel is uniformly burned on the hearth (fireplate), and the clinker and ash after combustion do not adhere to the hearth (fireplate) and are excellent in combustibility and maintainability.
(2) Since the hearth (fireplate) has a truncated cone shape, the burning pellet fuel is completely burned while falling along an inclined surface forming a grate.
(3) Since the scraper formed so that the protrusion or tongue piece serving as the stirring baffle plate is located in the combustion temperature zone (the highest position of the combustion temperature) where the clinker is easily generated on the hearth (fireplate) The production of clinker can be suppressed.

It is a front view which shows the warm air generator which concerns on this invention. It is a right view of FIG. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is a perspective view around a combustion pan. (A) is a top view of a combustion pan, (b) is CC sectional view taken on the line. It is a side view which shows one Example of a scraper. It is a side view which shows the other Example of a scraper. It is explanatory drawing which shows the combustion temperature zone of a hearth (fireplate). It is a graph which shows the differential thermal analysis result of platinum ash.

  An embodiment of the hot air generator of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1 to FIG. 4, a hot air generator 1 according to the present invention includes a combustion furnace 2 that burns solid fuel P such as wood pellets inside the apparatus body, and is heated by the combustion furnace 2. Air is sent to the heat exchanger 3, and the warm air obtained by heating the outside air sucked into the apparatus main body by the intake fan 4 by the heat exchanger 3 is supplied from the warm air blower port 5 to facilities such as agricultural greenhouses. It is a device to do.

  In the combustion furnace 2 to which the solid fuel P is supplied, a frusto-conical hearth (fireplate) 6 that holds the solid fuel P and maintains a combustion state is mounted. This hearth (fireplate) 6 is pivotally supported so as to be rotatable in the horizontal direction, and is configured to be able to burn while rolling or flowing the solid fuel P on the hearth 6. As a result, wood pellets made from wood or bark are continuously burned over a long period of time to generate stable warm air that can be fed into the desired facility.

  As described above, the hot air generator 1 can be used to heat the inside of a facility such as a greenhouse for plant cultivation such as a greenhouse or a house. The warm air blown by the hot air generator 1 of the present embodiment is not combustion gas but outside air heated by the heat exchanger 3, and therefore does not contain harmful substances such as carbon monoxide, so It can be used for heating of houses and houses.

  Examples of the solid fuel derived from biomass include solid fuels such as wood pellets. These wood-based pellets are fuels made from wood, and are attracting attention as carbon-neutral fuels for global warming countermeasures. There are many types of wood pellets, such as those made from conifers and hardwoods. The whole xylem, such as bark pellets made only from the bark, white pellets made from only the trunk except the bark, and thinned wood. The whole wood pellet etc. which used as a raw material etc. are mentioned, All can be used as a fuel of the warm air generator of this invention. In addition, those obtained by drying and solidifying livestock dung are also included in the biomass fuel. Hereinafter, for convenience, these biomass solid fuels will be simply referred to as “pellet P”.

  The combustion furnace 2 is a cylindrical container that burns the pellets P. The pellet P put into the combustion furnace 2 burns while being placed and held on a frustoconical hearth (fireplate) 6 provided at the top of the combustion furnace 2, and the heated air is transferred to the heat exchanger 3. It is structured to send out. The frusto-conical hearth (fireplate) 6 has a function of continuously maintaining combustion by rotating in the horizontal direction while holding the pellets P charged in the combustion furnace 2.

  The pellets P introduced from the fuel supply hopper 15 are pushed out in the horizontal direction by the screw-type pellet supply conveyor 10 and conveyed into the combustion furnace 2. The combustion furnace 2 includes a cylindrical pellet supply cylinder 8 that is formed upright from the front end side of the pellet supply conveyor 10 and a truncated cone-shaped hearth that is attached to the top of the pellet supply cylinder 8. (Pellet) 6 and the pellet P is extruded from an opening 6a provided in the center of the hearth (fireplate) 6 and blown and supplied to the upper surface of the hearth (fireplate) 6. It is burned continuously while gradually descending the surface. The hearth (fireplate) 6 is provided with a plurality of rooster holes 6b penetrating vertically, supplying combustion air to the pellets P on the hearth (fireplate) 6, and the hearth (fireplate). The combustion ash that burns completely on the 6th surface is dropped and discharged.

  Here, the pellet supply conveyor 10 includes a shaft 10b including screw blades 10c along the axis of the cylindrical pipe 10a, and includes a drive unit such as an electric motor 11 that drives the shaft 10b. The fuel supply hopper 15 is connected to the base end side of the cylindrical pipe 10a.

  Thus, the pellet P passing through the pellet supply opening 6a of the hearth (fireplate) 6 by supplying the pellet P to the upper surface of the hearth 6 while ejecting the pellet P from the lower surface side of the hearth (fireplate) 6. As a result of this flow, ash, unburned matter, clinker, and the like are not attached and blocked on the edge of the opening 6a, and the combustion state can be kept constant at all times. The hearth (fireplate) 6 is provided so as to be rotatable by a geared motor (not shown) or the like in the horizontal direction, and is provided at a position where the pellet P at the center of the hearth 6 is lifted by a screw feeder. The pellet P once ignited by a coiled electric heater or the like (not shown) is sequentially burned successively.

  Further, a scraper 7 is attached to the hearth (fireplate) 6. The scraper 7 includes protrusions or projecting pieces 7a that swivel with a predetermined gap along the radial direction of the leg 7c and the hearth (fired floor) 6 fixed to the outer peripheral surface of the cylinder 2a of the combustion furnace 2. It is a substantially L-shaped member such as made of heat-resistant steel or wear-resistant steel. As shown in FIG. 7, the scraper 7 has a 6c rib on the periphery of the rooster when the tilt angle of the rooster is large (for example, an inclination angle of 5 degrees or more). It is recommended that you fry in. The scraper 7 according to the present embodiment has two protrusions 7a and 7b, which branch in a direction perpendicular to the scraper 7 at a predetermined interval, and are deposited on the protrusion 7a as a baffle plate and the periphery of the hearth 6 A protruding piece 7b for removing the burning ash which tends to be present is provided. Then, by rotating the hearth (fireplate) 6, the pellet P burning on the hearth (fireplate) 6 is agitated or unburned material is crushed, and combustion ash is removed from the hearth (fireplate) 6. It can be efficiently dropped and discharged out of the combustion furnace from the rooster hole 6b.

  The scraper 7 extends in the radial direction so as to follow the upper surface inclination of the inclination angle (for example, 3 to 10 degrees) of the hearth (fireplate) 6, and a protrusion or protruding piece 7 a protruding downward in the middle is provided. One or a plurality are integrally formed. The protrusions or projecting pieces 7a are disposed on the hearth (fireplate) 6 so as to be positioned in a combustion temperature zone where clinker is likely to be generated (a zone where the combustion temperature is highest), and the pellet P during combustion is stirred or The action of a baffle plate that crushes the unburned matter that has been generated on the clinker can be exhibited, and the generation of clinker can be suppressed. In addition, it is preferable to arrange | position the lower end of this processus | protrusion or the protrusion piece 7a with a slight gap | interval of the hearth (fireplate) 6 upper surface and a play extent, and can suppress clinker production | generation effectively.

  As shown in FIG. 8, if the inclination angle of the rooster is horizontal or small (for example, less than 5 degrees), the peripheral wall (rib) 6c at the periphery of the rooster is not necessary, and the scraper 7 has only one protrusion 7a. May be provided. The scraper 7 according to the present embodiment has two protrusions 7a and 7b, which branch in a direction perpendicular to the scraper 7 at a predetermined interval, and are deposited on the protrusion 7a as a baffle plate and the periphery of the hearth 6 A protruding piece 7b for removing the burning ash which tends to be present is provided. Then, by rotating the hearth (fireplate) 6, the pellets P burning on the hearth 6 are agitated or unburned material is crushed, and the combustion ash is lost in the rooster hole 6 b of the hearth (fireplate) 6. Can be efficiently dropped to the outside of the combustion furnace.

  Here, as a rotation mechanism of the hearth (bakeware) 6, for example, a plurality of gear teeth 9 are arranged at equal intervals on the lower circumferential portion of the hearth (bakeware) 6, and at the front end side of the pellet feed shaft 11 b. It is possible to employ a pinion rack type rotation mechanism in which the rotating blades 11a that can be sequentially engaged with the gear teeth 9 are fixed coaxially, and are rotated by pressing the gear teeth 9 in synchronization with the rotation of the pellet feed shaft 11b. it can. In this case, the rotation speed of the hearth (fireplate) 6 is preferably, for example, in the range of 0.5 to 0.15 rpm. If it is faster than this, it is unburned, and if it is slow, it has been found that clinker is likely to be generated. . In this embodiment, the hearth (fireplate) 6 is rotated and the scraper 7 is fixed. However, the reverse configuration may be used, and either the hearth (fireplate) 6 or the scraper 7 is in relation to the other. Any configuration that relatively rotates can be used.

Combustion ash can be discharged to the outside by driving an ash removal feeder 13 provided below the combustion furnace 2 with an ash removal feeder motor 14. The ash removal feeder 13 is a screw conveyor having the same specifications as the pellet supply conveyor 10.

  In addition, as shown in FIG. 9, the present inventors have a flame temperature of the hearth (fireplate) 6 of 850 to 900 ° C., and a high temperature zone of 1100 to 1250 ° C. from the center of the hearth (fireplate) 6. Appearing in the shape of a concentric ring, it was learned that clinker was formed in this annular part. That is, it has been found that the combustion temperature is lowered by collapsing the pellet P in the high temperature range of 1100 to 1250 ° C., and the generation of clinker can be prevented. Moreover, as shown in the graph of FIG. 10, when the clinker by platinum ash was subjected to differential thermal analysis, it was found that the endothermic point, that is, the freezing point was about 1250 ° C. Therefore, theoretically, the combustion of pellets P in the temperature range below 1250 ° C. where clinker is generated can be prevented by generating and pulverizing with a scraper 7, but in order to ensure certainty, The desired effect can be obtained by projecting the scraper 7 into a high temperature range of 1100 to 1250 ° C. of the hearth 6.

  In the hot air generator 1 of this embodiment, the rotational speed adjustment of the hearth 6 and the warm air blowing operation are controlled based on the temperature measurement values measured by the temperature sensor that detects the temperature in the combustion furnace 2. It is also possible to provide a control unit. Moreover, the supply amount of the pellet P to the hearth (fireplate) 6 can also be adjusted based on the temperature measurement value measured by the temperature sensor.

  In addition to various sensors such as a temperature sensor and a hot air sensor, such a control unit is electrically connected to a conveyor, a driving motor, an intake / exhaust fan, a combustion air pushing fan, etc., and is preset by an operation program. The combustion state of the combustion furnace 2 can be determined based on the measured temperature data and the like, and the hearth rotation speed, the amount of pellets P supplied, the amount of outside air and warm air can be controlled appropriately. Thus, by controlling the combustion state of the pellets P, it is possible to send out hot air stably over a long period of time.

  The hot air generator of the present invention can provide stable hot air while using biomass pellets as fuel, and can send out stable hot air over a long period of time. Extremely expensive.

DESCRIPTION OF SYMBOLS 1 Hot air generator 2 Combustion furnace 2a Hearth holding cylinder 3 Heat exchanger 4 Intake fan (atmosphere)
5 Warm air vent 6 Hearth (fireplate)
6a Pellet supply port 6b Rooster hole 6c Peripheral guide (peripheral wall)
7 Scraper 7a Protrusion 8 Pellet supply tube (support shaft)
9 Gear teeth 10 Pellet feed conveyor 10a Cylindrical pipe 10b Pellet feed shaft 10c Screw blade 11 Pellet feed conveyor motor 11a Rotating blade 11b Pellet feed shaft 12 Combustion air pushing fan 13 Ashing feeder 14 Ashing feeder motor 15 Pellet feeding hopper P pellet (solid fuel)

Claims (3)

A hot air which arranges a combustion furnace which burns biomass-derived solid fuel and a combustion dish which rotates this combustion furnace in a horizontal direction inside, and heats air supplied from the outside in the combustion furnace to generate hot air In the generator, the combustion dish is formed in a truncated cone shape having a high center part and a low outer peripheral part, and an air blowing hole for discharging combustion air is penetrated below the combustion dish. Arranged along the radial direction of the hearth surface of the combustion furnace to which the solid fuel to be supplied is burned by supplying the air discharged outward from the blow hole to the combustion dish and the surrounding fuel, and burning the solid A hot air generator comprising a scraper that stirs fuel and pulverizes a clinker that is being produced , and has a protrusion protruding in a high temperature zone of 1100 to 1250 ° C. of the combustion dish . The hot air generator according to claim 1 , wherein the combustion dish includes a hole-shaped opening through which the solid fuel pushed up from the fuel conveyance unit passes . The hot air generator according to claim 1 or 2 , wherein the combustion dish and the scraper rotate relatively .