JP2010230230A - Boiler system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dry wood chips by using steam of a boiler device and minimizing its used steam amount, to secure a steam amount to be used as a primary heat source, to improve drying capacity even with use of a small steam amount, and to improve combustibility. <P>SOLUTION: The boiler system includes a drying conveyance device 30 conveying wood chips W supplied a predetermined amount from a supply device 1 while drying, and the boiler device 60 burning the wood chips W from the drying conveyance device 30 and generating steam by heat exchange of combustion gas and water. The drying conveyance device 30 is composed by providing a cylindrical outer shell 33 forming a conveyance space E of the wood chips W by an inner side conveyor, a steam circulation space S is provided in the outer shell 33, a steam feeding pipe line 47 feeding one part of the steam generated by the boiler device 60 is arranged in the steam circulation space S, and an exhaust gas feeding pipe line 50 feeding one part of exhaust gas exhausted from the boiler device 60 is arranged in the conveyance space E of the outer shell 33. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a boiler system that generates steam by burning wood chips such as bark, wood chips and sawdust.

Conventionally, as this type of boiler system, for example, a technique described in JP-A-11-148626 (Patent Document 1) is known.
As shown in FIG. 9, the boiler system includes a silo 200 that stores wood chips W such as wood chips, wood powder, and bark (bark) having different shapes, sizes, physical properties, moisture percentages, and the like. A supply device 201 that supplies a predetermined amount of chips W, a drying and conveying device 203 that includes a shooter that conveys the wood chips W supplied by the supplying device 201 while drying, and a wooden chip W that is conveyed by the drying and conveying device 203 is burned. A boiler device 206 including a boiler 205 that burns in a chamber 204 and generates steam by heat exchange between combustion gas obtained by the combustion and water is provided. The wood chips W accumulated in the silo 200 are supplied to a feeder 209 that controls the supply amount via a supply conveyor 207 and a return conveyor 208 that returns the excess wood chips W to the silo 200.

  Primary air is fed into the combustion chamber 204 of the boiler device 206 from the lower portion of the combustion chamber 204 by the primary blower 210, and secondary air is fed into the combustion chamber 204 by the secondary forced air blower 211. The secondary air is preheated by the heat of the exhaust gas in the air preheater 212. The drying conveyance device 203 blows a part of the preheated secondary air from the upper air blowing port 213 to supply the wood chip W into the combustion chamber 204 while drying it. As a result, the wood chip W is slightly dried by the drying function of the drying transport device 203 to improve the combustion efficiency.

  Conventionally, there are various dry conveying apparatuses for drying an object to be dried. For example, as described in Japanese Patent Application Laid-Open No. 2005-241239 (Patent Document 2), a dry object is contained in a cylinder. In some cases, the cylinder is indirectly heated by steam and / or the steam is fed into the cylinder to directly heat the dried product to dry the dried product. It is also conceivable to incorporate this steam-drying type drying / conveying device into the above boiler system so that the steam of the boiler is used as a steam source.

JP-A-11-148626 JP 2005-241239 A

By the way, in the boiler system using the conventional shooter-type drying and conveying apparatus 203, the wood chip W is slightly dried by the secondary air preheated in the drying and conveying apparatus 203 so as to improve its combustion efficiency. However, since the air for drying is generated in the air preheater 212, the temperature is not so high, and there is a problem that the drying capacity is inferior. In particular, the wood chip W, for example, in the case of bark, which is not dried, has a relatively high moisture content and may be frozen in winter, etc. In such a wood chip that is frozen, The combustion efficiency in the boiler device 206 is significantly reduced.
For this reason, as described above, it is conceivable to change from a shooter type as a drying conveyance device to a steam drying type that uses the steam of the boiler device as a steam source, however, the amount of steam used in the boiler device increases. Therefore, there is a problem that the amount of steam that is desired to be used as the original heat source is reduced.

  The present invention has been made in view of the above-mentioned problems, and makes it possible to dry the wood chip by using the steam of the boiler apparatus as much as possible to use the steam, and to use the steam as an original heat source. It is an object of the present invention to provide a boiler system that can improve the drying ability even when using a small amount of steam and improve the combustibility in the boiler device.

  In order to achieve such an object, the boiler system of the present invention includes a supply device for supplying a predetermined amount of wood chips, a drying transport device for transporting the wood chips supplied by the supply device while drying, and the dry transport A boiler system comprising a boiler device that burns wood chips conveyed by the apparatus, generates steam by heat exchange between combustion gas obtained by the combustion and water, and exhausts the combustion gas after the heat exchange as exhaust gas In the above, the drying conveying device has a receiving port for receiving the wooden chip supplied from the supply device on one end side, a discharge port for discharging the wooden chip on the other end side, and a wooden chip conveying space on the inner side And a conveyor that conveys the wood chip that is provided in the conveyance space formed by the outline toward the discharge port. A conveyor driving unit for driving the conveyor, and the outer shell is provided on a cylindrical outer wall and on the inner side of the outer wall so as to form a steam circulation space through which steam can flow. An inner wall is provided, a steam inlet for allowing steam to flow into the steam circulation space and a steam outlet for allowing steam to flow out are provided in the outer shell, and a part of the steam generated by the boiler device is provided at the steam inlet. A steam feed pipe for feeding into the steam circulation space is provided, and a gas inlet for injecting exhaust gas into the transport space and a gas outlet for discharging the exhaust gas are provided in the outer shell, and the gas inlet has the above-mentioned An exhaust gas supply pipe for supplying a part or all of the exhaust gas exhausted from the boiler device into the transfer space is provided.

  Thus, when the wood chips are quantitatively supplied from the supply device, the wood chips are transported in the dry transport device and reach the boiler device. In the boiler device, this wood chip is burned, steam is generated by heat exchange between the combustion gas obtained by combustion and water, and the combustion gas after the heat exchange is exhausted as exhaust gas. A part of the steam generated in the boiler device is fed to the drying and conveying device through the steam feed pipe, is introduced into the steam circulation space from the steam inlet, and is discharged from the steam outlet. To go. Thereby, the outer wall and inner wall of the outer shell are heated. In addition, a part or all of the exhaust gas from the boiler device is fed to the drying and conveying device through the exhaust gas supply pipe, and flows into the conveying space from the gas inlet and flows out from the gas outlet and exhausted. Go.

At this time, in the drying and conveying apparatus, the wood chips are received from the outer entrance and conveyed by the conveyor driven by the conveyor driving unit, discharged from the discharge port, and supplied to the boiler device. Since the exhaust gas having a high temperature from the boiler device flows into the transfer space, the wood chip is heated and dried by the exhaust gas, and the moisture content of the wood chip is lowered. The water vapor from the wood chip is mixed in the exhaust gas and flows out from the gas outlet and is exhausted.
In this case, since the outer wall and inner wall of the outer shell are heated by steam, the temperature of the inner wall is also high. Therefore, the wood chip is also indirectly heated by steam through the inner wall to promote drying. The Also, in this case, the outer wall and inner wall of the outer shell are heated by steam to form a heat insulating wall, so that the heat of the exhaust gas in the transfer space is difficult to escape to the outside through the outer shell, so that the wood chip The heat is reliably transferred and drying is promoted. As a result, it becomes possible to dry the wood chip by using the steam of the boiler device as much as possible, and the drying capacity is improved even with the use of a small amount of steam. Combustibility is improved. The steam from the boiler device is used as a heat source, for example for heating, but since the amount of steam used in the drying / conveying device is small, it is possible to ensure the amount of steam that is desired to be used as the original heat source. it can.

  And if necessary, the amount of steam fed through the steam feed conduit is set to 5% or less of the total amount of steam generated by the boiler device. Preferably, it can be made 2% or less. The amount of steam used is surely reduced, and the amount of steam desired to be used as the original heat source can be ensured.

  In this case, it is effective to provide a heat insulating layer on the outer side of the outer wall of the outer shell. Since the outer wall and inner wall of the outer shell are heated by steam, heat tends to escape from the outer wall to the outside, but heat transfer is interrupted by the heat insulating layer, making it difficult for the heat to escape from the outer wall. The heat of the exhaust gas is more difficult to escape to the outside through the outer shell, and the wood chip can be reliably dried in the transfer space.

  Further, if necessary, an exhaust gas temperature adjusting unit for adjusting the temperature of the exhaust gas by introducing outside air into the exhaust gas supply pipe is provided. Since the temperature of the exhaust gas can be adjusted, the drying temperature of the wood chip in the transfer space can be made appropriate.

  Further, if necessary, the outer shell is provided with a cylindrical outer wall and a cylindrical inner wall that is provided inside the outer wall and forms a steam circulation space through which steam can flow. The conveyor Is constituted by a screw conveyor provided with a rotating shaft having an axis in the direction along the center line of the inner wall and a spiral blade provided on the outer periphery of the rotating shaft, and the rotating shaft of the screw conveyor is One end of the rotating shaft is pivotally supported on one end of the outer shell so that the axis is eccentrically positioned below the center line of the inner wall, and the other end of the rotating shaft is pivotally supported on the other end of the outer shell, An extra space is formed above the screw conveyor in the transfer space. Since there is an extra space, the moisture in the wood chip is easily evaporated and mixed in the exhaust gas, and the drying efficiency is improved.

  Furthermore, the gas inlets of the outer shell are provided on both sides on one end side of the outer shell, and the exhaust gas supply pipe is configured to each gas inlet and a straight gas injection pipe having a predetermined length is connected thereto. The gas injection pipe is connected so as to be inclined so that the tip end side in the injection direction of the axis is directed toward the center line of the inner wall and toward the other end side of the outer shell. Exhaust gas injected from the gas injection pipe easily flows along the direction of the center line of the inner wall, so that the exhaust gas is uniformly contacted with the wood chip, and drying is performed reliably.

  In addition, if necessary, the supply device is installed between a pair of endless drive chains, a conveying member that conveys the wood chip on the forward path side above the drive chain, and a pair of drives over which the drive chain is bridged A sprocket and at least one of the drive sprockets, and the feed member configured to move the wood chip along the transport direction toward the receiving port of the drying transport device by the transport member. A thickness regulating mechanism for regulating the carrying thickness of the wood chip carried by the carrying member is provided above the wood chip, and the thickness regulating mechanism is installed between a pair of operating chains and carried by the carrying member. A plurality of ridge members whose leading edges are in contact with each other, a pair of operation sprockets on which the operation chain is bridged, and the ridge members Wood chips being transported by the serial conveying member is constituted by a thickness regulating driving unit for rotating the one operating sprocket least one so as to move in the opposite direction of its conveyance direction. The regulation mechanism leveles the wood chips so that they move in the direction opposite to the conveying direction, so that the thickness regulation of the wood chips is reliably performed, so that the supply amount can be reliably fixed, so that the dry conveying device Can be uniformly performed, and combustion in the boiler device can be reliably performed.

  In this case, the conveying member of the supply device is configured by a large number of buckets arranged in a line between a pair of endless drive chains and opened on the forward path side of the upper side of the drive chain and released on the front side in the conveyance direction. It is effective to provide a support plate for supporting the bucket on the forward path side on the upper side of the drive chain. Since the bucket is supported and moved by the support plate, even if the wood chip is interposed between the buckets, it is supported by the support plate and transported by the movement of the bucket, so the wood chip is reliably transported without falling down Is done.

If necessary, the above boiler device is surrounded by a furnace wall and combusts wood chips, and heat is exchanged between the combustion gas of the wood chips and water provided above the combustion chamber to generate steam. The heat exchange unit is configured to include a water pipe part to which water is supplied, and the water pipe part is housed and has a gas inlet for exhaust gas from the combustion chamber on the lower side. And a heat insulating wall that forms an exhaust gas space through which the exhaust gas circulates, and the water pipe portion is bent into a substantially rectangular shape with one side and the other side facing the one side. A lower main water pipe having a water supply port for water, and a substantially rectangular shape having one side and the other side opposite to the one side while being arranged on the upper side of the lower main water pipe corresponding to the lower main water pipe An upper main water pipe having a steam outlet, and one side of the lower main water pipe and the upper side. A first installed water pipe having a plurality of branch pipes installed in a row between the other sides of the main water pipe and having adjacent branch pipes connected by a connecting plate, and the other side of the lower main water pipe A second installed water pipe having a plurality of branch pipes installed in a row between the upper main water pipe and one side of the upper main water pipe and having adjacent branch pipes connected by a connecting plate; and the lower main water pipe A third installed water pipe having a plurality of branch pipes installed in a row between one side and one side of the upper main water pipe and having adjacent branch pipes connected by a connecting plate; and the lower main water pipe A fourth installed water pipe having a plurality of branch pipes installed in a row between the other side and the other side of the upper main water pipe and having adjacent branch pipes connected by a connecting plate. And a lower exhaust gas space surrounded by the lower side of the first erection water pipe and the lower side of the second erection water pipe, the upper side of the first erection water pipe and the second erection water pipe A pair of upper exhaust gas space surrounded by the side, the first erection water pipe, the second erection water pipe and the third erection water pipe and surrounded by the first erection water pipe, the second erection water pipe and the fourth erection water pipe The side exhaust gas space is formed, and the exhaust gas space is formed so that the path from the gas inlet to the gas outlet of the exhaust gas from the combustion chamber is in the order of the lower exhaust gas space, the side exhaust gas space, and the upper exhaust gas space. .
In the heat exchange section, the exhaust gas space is formed so that the path from the gas inlet to the gas outlet of the exhaust gas is in the order of the lower exhaust gas space, the side exhaust gas space, and the upper exhaust gas space, so that it becomes a so-called three-path, and heat exchange is ensured. To be done. Moreover, since the 3rd construction water pipe and the 4th construction water pipe were provided, the surface area of heat exchange increases that much, and heat exchange efficiency is improved. As a result, the steam can be generated at a high temperature, and the thermal energy of a part of the steam sent to the drying and conveying device can be increased accordingly. Can be improved.

  According to the boiler system of the present invention, since the exhaust gas having a high temperature from the boiler device flows into the drying conveyance device, the wood chip is heated and dried by the exhaust gas, and the water content of the wood chip is increased. The rate will be lowered. In this case, since the outer wall and inner wall of the outer shell are heated by steam, the wood chip can be heated indirectly by steam through the inner wall to promote drying, and the outer wall and inner wall of the outer shell can be heated by steam. Heating will form a heat insulation wall, which makes it difficult for the heat of the exhaust gas in the transfer space to escape to the outside through the outer shell, so that heat is reliably transmitted to the wood chip and promotes drying be able to. As a result, it becomes possible to dry the wood chip using the steam of the boiler device as much as possible, and improve the drying capacity even with the use of a small amount of steam. The combustibility can be improved, and the amount of steam used in the drying / conveying device can be reduced, so that the amount of steam desired to be used as the original heat source can be ensured.

It is a figure showing a boiler system concerning an embodiment of the invention. The supply apparatus of the boiler system which concerns on embodiment of this invention is shown, (a) is a front view, (b) is a side view. The drying conveyance apparatus of the boiler system which concerns on embodiment of this invention is shown, (a) is side sectional drawing, (b) is a partial top view. It is a cross-sectional view which shows the drying conveyance apparatus of the boiler system which concerns on embodiment of this invention. It is a figure which shows the boiler apparatus of the boiler system which concerns on embodiment of this invention. It is sectional drawing of the boiler apparatus of the boiler system which concerns on embodiment of this invention. It is a perspective view which shows the principal part of a heat exchange part in the boiler apparatus of the boiler system which concerns on embodiment of this invention. The experimental example in the boiler system which concerns on embodiment of this invention is shown, (a) is a figure which shows a measurement item, (b) is a table | surface figure which shows the experimental result regarding the effect of steam insulation, (c) is bark input amount FIG. 6D is a table showing experimental results related to the influence, and FIG. 6D is a table showing experimental results related to the influence of the bark retention time in the tube. It is a figure which shows an example of the conventional boiler system.

Hereinafter, a boiler system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
The boiler system according to the embodiment of the present invention uses wood chips W as fuel as shown in FIGS. In the embodiment, the wood chip W is a raw bark, and is processed into a size of about several centimeters in advance by cutting or pulverizing with a known chipper (processing machine).
As shown in FIG. 1, the basic configuration of this boiler system includes a supply device 1 that supplies a predetermined amount of wood chips W, and a drying transport device 30 that transports the wood chips W supplied by the supply device 1 while drying them. And a boiler device 60 for generating steam by exchanging heat between the combustion gas obtained by combustion of the wood chip W conveyed by the drying conveyance device 30 and water and exhausting the combustion gas after heat exchange as exhaust gas. It is prepared for.

  As shown in FIGS. 1 and 2, the supply device 1 includes a machine base 2 and a hopper 3 provided on the machine base 2. The wood chips W stored in the storage tank 4 are transported to the hopper 3 by the belt conveyor 5 and loaded. The hopper 3 is provided with a level sensor (not shown). Based on the level sensor, the belt conveyor 5 is turned on and off so that the required amount of wood chips W is supplied into the hopper 3. Yes.

  Further, the supply device 1 is provided between a pair of endless drive chains 10 and a transport member 11 that receives and transports the wood chip W from the hopper 3 on the forward path side above the drive chain 10, and is pivotally supported on the machine base 2. A pair of drive sprockets 12 provided for each drive chain 10 and over which the drive chain 10 is bridged, and rotationally driven via the one drive sprocket 12, the wood chip W is dried by the transport member 11, which will be described later. And a supply drive unit 14 including an electric motor that moves along the conveyance direction toward the receiving port 31. The conveying member 11 of the supply device 1 is composed of a large number of buckets 15 arranged in a line between a pair of endless drive chains 10 and opened on the forward path side of the upper side of the drive chain 10 and on the front side in the conveying direction. Yes. Further, the machine base 2 is provided with a support plate 16 that supports the bucket 15 on the forward path side on the upper side of the drive chain 10.

  Further, a thickness regulating mechanism 20 that regulates the carrying thickness of the wood chip W carried by the carrying member 11 is provided above the carrying member 11. The thickness regulating mechanism 20 is pivotally supported by the machine base 2 and a large number of plate-like ridge members 22 whose tip edges come into contact with the wood chips W that are installed between the pair of operating chains 21 and are conveyed by the conveying member 11. A pair of actuating sprockets 23 provided for each actuating chain 21 and spanning the actuating chain 21 and a wood chip W conveyed by the conveying member 11 by the ridge member 22 move in a direction opposite to the conveying direction. A thickness regulating drive unit 25 made of an electric motor that rotationally drives at least one of the operating sprockets 23 via a chain transmission mechanism 24 is provided. That is, the thickness regulating mechanism 20 has a structure in which a large number of protruding members 22 are provided on the belt conveyor, and the protruding members 22 on the one side of the operating sprocket 23 are close to the conveying member 11 side and the interval therebetween. It is installed in the machine base 2 so that the angle θ of the axis connecting the centers of the pair of operating sprockets 23 can be varied so that h can be adjusted. Thereby, the conveyance amount is regulated so that the height (h) of the wood chip W conveyed by the conveyance member 11 with respect to the conveyance member 11 becomes constant.

  As shown in FIGS. 1, 3 and 4, the drying / conveying device 30 has a receiving port 31 for receiving the wood chip W supplied from the supply device 1 on one end side, and the wood chip W on the other end side. A cylindrical outer shell 33 having a discharge port 32 for discharging and forming a conveying space E for the wooden chip W inside, and a wooden chip W provided in the conveying space E formed by the outer shell 33 and received by the receiving port 31. Is provided with a screw conveyor 40 as a conveyor that conveys the toner toward the discharge port 32, and a conveyor driving unit 43 that drives the screw conveyor 40.

  The outer shell 33 is formed of a cylindrical metal that forms an outer wall 34 formed of a cylindrical metal tube and a steam circulation space S that is provided inside the outer wall 34 and is a closed space in which steam can flow between the outer wall 34. An inner wall 35 made of a tube is provided. The inner wall 35 protrudes from both ends of the outer wall 34, and both ends thereof are closed by end face plates 36 and 37. Further, a heat insulating layer 38 in which a heat insulating material such as glass wool is covered with a sheet material is provided outside the outer wall 34 of the outer shell 33.

  The screw conveyor 40 includes a rotary shaft 41 having an axis Q in a direction along the center line P of the inner wall 35, and a spiral blade 42 provided on the outer periphery of the rotary shaft 41. The rotary shaft 41 of the screw conveyor 40 is pivotally supported at one end of the rotary shaft 41 by the end face plate 36 at one end of the outer shell 33 so that the axis Q is eccentrically positioned below the center line P of the inner wall 35. The other end of the shaft 41 is pivotally supported by an end face plate 37 at the other end of the outer shell 33, whereby an extra space Ea is formed above the screw conveyor 40 in the transport space E. The conveyor drive unit 43 is configured by an electric motor that rotationally drives the other end side of the rotary shaft 41 via a chain transmission mechanism 44.

  The outer wall 34 of the outer shell 33 is provided with a steam inlet 45 through which steam flows into the steam circulation space S and a steam outlet 46 through which steam flows out. The steam inlet 45 is provided with a steam supply pipe 47 for feeding a part of the steam generated by the boiler device 60 into the steam circulation space S. The steam supply pipe 47 is branched and connected to a steam outlet 92 a described later of the boiler device 60. The connecting portion of the steam outlet 92a is provided with an adjusting valve 48 (FIG. 1) for adjusting the amount of steam supplied to the steam supply pipe 47. By adjusting the adjusting valve 48, the steam supply pipe is adjusted. The amount of steam supplied through the passage 47 is set to be 5% or less, preferably 2% or less of the total amount of steam generated by the boiler device 60. In the embodiment, it is 1.4%.

  In addition, a gas inlet 51 through which exhaust gas flows into the transfer space E is provided on one end side of the outer shell 33, and a gas outlet 52 through which exhaust gas flows out is provided on the other end side of the outer shell 33. Yes. The gas inlet 51 is provided with an exhaust gas supply conduit 50 that supplies a part or all of the exhaust gas exhausted from the boiler device 60 (part in the embodiment) into the transfer space E. . As shown in FIG. 3B, the gas inlet 51 of the outer shell 33 is provided on both sides on one end side of the outer shell 33, and each gas inlet 51 includes an exhaust gas supply conduit 50. A straight gas injection pipe 53 having a predetermined length is connected to one end of the exhaust gas supply pipe 50. The gas injection pipe 53 is connected so as to be inclined such that the tip end side in the injection direction of the axis R is directed toward the center line P of the inner wall 35 and toward the other end side of the outer shell 33.

As shown in FIG. 1, the other end of the exhaust gas supply pipe 50 is branched and connected to a gas outlet 82 described later of the boiler device 60. A gas adjusting valve (not shown) for adjusting the amount of exhaust gas supplied to the exhaust gas supply pipe 50 is provided at the connection portion of the gas outlet 82. The exhaust gas supply pipe 50 is provided with a suction blower 54 that sucks exhaust gas from the boiler device 60. The suction blower 54 is provided with an exhaust gas temperature adjusting unit 55 that introduces outside air into the exhaust gas supply pipe 50 to adjust the temperature of the exhaust gas. In the embodiment, for example, the exhaust gas at 400 ° C. is adjusted to 200 ° C. by introducing the outside air into the exhaust gas temperature adjusting unit 55.
Further, the gas outlet 52 is provided with a discharge pipe 56 for discharging the exhaust gas flowing out from the transfer space E of the outer shell 33 to the outside air. The exhaust pipe 56 is provided with an exhaust blower 57 that sucks and exhausts exhaust gas from the transfer space E.

  The boiler device 60 has basically the same configuration as, for example, the boiler device disclosed in Japanese Patent Application Laid-Open No. 2006-207865, and as shown in FIGS. 1 and 5 to 7, a furnace made of a refractory material. A combustion furnace 62 having a combustion chamber 61 surrounded by a wall and burning wood chips W, and a wood chip W provided in the combustion chamber 61 to move in one direction from the front end side to the rear end side of the combustion furnace 62 A grate table 63 having a mounting surface to be mounted, an ignition burner 63a for igniting the wood chip W on the grate table 63, and a fuel supply for supplying the wood chip W to the upstream side of the grate table 63 , A moving mechanism 65 for moving the wood chip W supplied to the upstream side of the grate table 63 toward the downstream side, a combustion air supply unit 66 for supplying combustion air into the combustion chamber 61, and a combustion chamber The combustion gas of the wood chip W provided on the upper side of 61 Performing heat exchange between water and a boiler 80 as a heat exchange unit is constructed with.

In the combustion furnace 62, as shown in FIG. 6, in the combustion chamber 61, a partition between the grate base 63 and the boiler 80 serving as a heat exchanging portion is partitioned, and a passage port for the combustion gas to the boiler 80 side upstream. An arch-shaped partition wall 67 forming 67a is provided.
The fuel supply unit 64 is constituted by a screw conveyor that receives and transports the heated and dried wood chip W discharged from the discharge port 32 of the drying and conveying device 30 and supplies it into the combustion chamber 61 from the supply port 68. . Below the supply port 68, there is provided an inclined table 69 that slides the wooden chip W to the upstream side of the grate table 63 and drops it.

The moving mechanism 65 is provided so as to be movable back and forth along the mounting surface of the grate table 63 and pushes and moves the wood chip W dropped from the tilting table 69 at the time of advancement, and air for moving the pusher 70 forward and backward. Or it is comprised with the cylinder apparatus 71 of a hydraulic drive.
The combustion air supply unit 66 is combusted from a primary air supply unit 73 that blows combustion air from a blower outlet 72 provided on the mounting surface of the grate table 63 by a blower, and a jettage 74 provided on the furnace wall of the combustion furnace 62. The secondary air supply part 75 which ejects air with an air blower is comprised.

  A boiler 80 as a heat exchanging unit includes a water pipe unit 90 to which water is supplied, a water pipe unit 90, a gas inlet 81 for exhaust gas from the combustion chamber 61 on the lower side, and a gas outlet 82 on the upper side. The heat insulation wall 83 which forms the exhaust gas space F through which the exhaust gas which it has distribute | circulates is provided. The heat insulating wall 83 is formed of a refractory material and is integrally formed with the furnace wall of the combustion furnace 62. As shown in FIG. 5, a chimney device T having a chimney 84 is installed at a location appropriately separated from the combustion furnace 62, and a duct 85 communicating with the chimney of the chimney device T is connected to the gas outlet 82. ing. The chimney 85 is provided with an exhaust fan 86 that induces combustion exhaust gas from the gas outlet 82 to the chimney and is inverter-controlled.

  As shown in FIGS. 6 and 7, the water pipe portion 90 includes a lower main water pipe 91 having one side and the other side opposite to the one side and bent into a substantially rectangular shape and having a water supply port 91a. The upper side disposed on the upper side of the lower main water pipe 91 corresponding to the lower main water pipe 91 and having one side and the other side opposed to the one side and bent into a substantially rectangular shape and having a steam outlet 92a for steam. The main water pipe 92, a plurality of branch pipes 93a arranged in a row between one side of the lower main water pipe 91 and the other side of the upper main water pipe 92, and adjacent branch pipes 93a are connected to each other by a connecting plate 93b. Adjacent first branch water pipes 93, a plurality of branch pipes 94a installed in a row between the other side of the lower main water pipe 91 and one side of the upper main water pipe 92. 94a is connected with a connecting plate 94b, the second erected water pipe 94, one side of the lower main water pipe 91 and the upper main water A third erection water pipe 95 having a plurality of branch pipes 95a arranged in a row with one side of 92 and having adjacent branch pipes 95a connected by a connecting plate 95b, and a lower main water pipe 91 A fourth installed water pipe 96 having a plurality of branch pipes 96a arranged in a row between the other side and the other side of the upper main water pipe 92 and having adjacent branch pipes 96a connected by a connecting plate 96b; It is configured with.

  Accordingly, the lower exhaust gas space Fa surrounded by the lower side of the first erection water pipe 93 and the lower side of the second erection water pipe 94, and the upper exhaust gas surrounded by the upper side of the first erection water pipe 93 and the upper side of the second erection water pipe 94. A pair of sides surrounded by the space Fb, the first erection water pipe 93, the second erection water pipe 94, and the third erection water pipe 95 and by the first erection water pipe 93, the second erection water pipe 94, and the fourth erection water pipe 96 The exhaust gas space F is formed so that the path from the gas inlet 81 to the gas outlet 82 of the exhaust gas from the combustion chamber 61 is in the order of the lower exhaust gas space Fa, the side exhaust gas space Fc, and the upper exhaust gas space Fb. Forming.

Therefore, when the steam generated by burning the wood chip W by the boiler system according to the present embodiment, the operation is as follows.
When the wood chips W are quantitatively supplied from the supply device 1, the wood chips W are transported by the drying transport device 30 and reach the boiler device 60. In the boiler device 60, the wood chip W is burned, and steam is generated by heat exchange between the combustion gas obtained by combustion in the boiler 80 as a heat exchange unit and water, and the combustion gas after the heat exchange is exhaust gas. As exhausted.

  In the supply device 1, the wood chips W stored in the storage tank 4 are transported by the belt conveyor 5 and put into the hopper 3. The hopper 3 is provided with a level sensor (not shown). Based on the level sensor, the belt conveyor 5 is turned on and off so that the required amount of wood chips W is supplied into the hopper 3. Yes. As shown in FIG. 2, the wood chip W from the hopper 3 is received by the bucket 15 of the transport member 11, and the bucket 15 is supported by the support plate 16 and moves to receive the wood chip W at the receiving port of the drying transport device 30. Transport toward 31. In this case, since the bucket 15 is supported and moved by the support plate 16, the wood chip W is supported by the support plate 16 and conveyed by the movement of the bucket 15 even if the wood chip W is interposed between the buckets 15. W is reliably conveyed without falling down. Further, above the conveying member 11, the protrusion member 22 of the thickness regulating mechanism 20 moves endlessly, and the conveyed wood chip W is conveyed in the conveying direction by the protruding member 22 of the thickness regulating mechanism 20. The upper surface is leveled so that it moves in the opposite direction. Therefore, the thickness regulation of the wood chip W is surely performed, and the supply amount is reliably made constant.

  Further, in the drying and conveying apparatus 30, as shown in FIGS. 1, 3 and 4, the screw driven by the conveyor driving unit 43 by receiving the wood chip W received from the receiving port 31 from the receiving port 31 of the outer shell 33. It is conveyed by the conveyor 40, discharged from the discharge port 32, and supplied to the boiler device 60. In this state, a part of the steam generated by the boiler device 60 is fed through the steam feed pipe 47 and is introduced into the steam circulation space S from the steam inlet 45 and then the steam outlet 46. It will flow out of the water and be discharged. Thereby, the outer wall 34 and the inner wall 35 of the outer shell 33 are heated. In addition, a part of the exhaust gas from the boiler device 60 is supplied to the drying transfer device 30 through the exhaust gas supply pipe 50, is introduced into the transfer space E from the gas inlet 51, and flows out from the gas outlet 52. And exhausted. For this reason, since the exhaust gas having a high temperature from the boiler device 60 flows into the transport space E of the wood chip W, the wood chip W is heated and dried by the exhaust gas, and the water content of the wood chip W is increased. The rate will be lowered. The water vapor from the wood chip W is mixed into the exhaust gas and flows out from the gas outlet 52 and is exhausted. In this case, in the exhaust gas supply conduit 50, the exhaust gas temperature adjustment unit 55 introduces outside air to adjust the temperature of the exhaust gas, so that the drying temperature of the wood chip W in the transfer space E is set appropriately. Can be a thing.

  Further, in this case, since the outer wall 34 and the inner wall 35 of the outer shell 33 are heated by the steam, the temperature of the inner wall 35 is also high. Therefore, the wood chip W is indirectly heated by the steam through the inner wall 35. Drying is also promoted. Further, the outer wall 34 and the inner wall 35 of the outer shell 33 are heated by steam to form a heat insulating wall. Therefore, the heat of the exhaust gas in the transfer space E is difficult to escape to the outside through the outer shell 33, and the wood Heat is reliably transmitted to the chip W, and drying is promoted. In particular, since the heat insulating layer 38 is provided on the outer side of the outer wall 34 of the outer shell 33, heat transfer is blocked by the heat insulating layer 38 even if heat escapes from the outer wall 34 to the outside. It becomes more difficult to escape to the outside through 33, and the wood chip W can be reliably dried in the transfer space E.

  Furthermore, since the supply amount of the wood chips W from the supply device 1 is fixed, the speed of the screw conveyor 40 can be adjusted as appropriate to uniformly dry the wood chips W, and the subsequent boiler device 60 It is possible to make sure that combustion is performed. Furthermore, since the screw conveyor 40 is located eccentrically with respect to the center line of the inner wall 35 and forms a surplus space Ea above the screw conveyor 40 in the conveying space E, the surplus space Ea causes the inside of the wood chip W. Moisture is easily evaporated and mixed into the exhaust gas, and drying efficiency is improved. Further, as shown in FIG. 3B, the gas injection pipe 53 is connected so as to be inclined so that the tip end side in the injection direction of the axis R is directed toward the center line P of the inner wall 35 and toward the other end side of the outer shell 33. Therefore, the exhaust gas injected from the gas injection pipe 53 is likely to flow along the direction of the center line P of the inner wall 35, so that the exhaust gas is uniformly contacted with the wood chip W, and also in this respect, drying is surely performed. Is called.

  And in the dry conveyance apparatus 30, the vapor | steam amount supplied with the vapor | steam supply pipe line 47 is 5% or less of the total vapor amount produced | generated with the boiler apparatus 60, and is 1.4% in embodiment. Therefore, the amount of steam used is extremely small. As a result, the wood chip W can be dried by using the steam of the boiler device 60 as much as possible, and the drying ability can be improved even when the steam amount is small.

  In the boiler device 60, the wood chip W is supplied from the fuel supply unit 64 to the upstream side of the grate table 63, and the wood chip W is moved downstream by the moving mechanism 65. W burns in the combustion chamber 61 in the order in which it is moved downstream. In this combustion, ignition control of the ignition burner 63a, supply amount control of the wood chip W of the supply device 1, control of the movement amount of the moving mechanism 65, and control of the air amount of the combustion air supply unit 66 are performed. The wood chip W can be smoothly burned according to the water content of W. In this case, since the moisture content of the wood chip W is reduced in the drying conveyance device 30, the combustion efficiency in the boiler device 60 is improved, and combustion can be performed reliably.

  The combustion gas generated in the combustion chamber 61 rises and reaches the gas outlet 82 from the gas inlet 81 of the boiler 80 as a heat exchanging portion. In the process, heat is exchanged between the combustion gas and water. At this time, as shown in FIGS. 6 and 7, the path from the gas inlet 81 to the gas outlet 82 of the exhaust gas in the exhaust gas space F is in the order of the lower exhaust gas space Fa, the side exhaust gas space Fc, and the upper exhaust gas space Fb. Thus, a so-called three-pass is formed, and heat exchange between the water flowing through the first erection water pipe 93, the second erection water pipe 94, the third erection water pipe 95, and the fourth erection water pipe 96 and the exhaust gas is reliably performed. Further, since the third erection water pipe 95 and the fourth erection water pipe 96 are provided in addition to the first erection water pipe 93 and the second erection water pipe 94, the surface area of the heat exchange is increased accordingly, and the heat exchange efficiency is improved. As a result, the steam can be generated at a high temperature, and the thermal energy of a part of the steam fed to the drying transport device 30 can be increased. Can be improved. Further, the steam from the boiler device 60 is used as a heat source, for example, for heating. However, since the amount of steam used in the drying / conveying device 30 is small, the amount of steam desired to be used as the original heat source can be ensured. Can be secured.

<Experimental example>
Next, an experimental example is shown. This is because bark is used as the wood chip W, and as shown in FIG. 8A, the temperature of the wood chip W received at the receiving port 31 of the drying conveyance device 30 is Tbi, the moisture content is MCi, and the input exhaust gas The following experiment was performed with the temperature Tgi, the temperature of the wood chip W discharged from the discharge port of the drying conveyance device 30 as Tbo, the moisture content as MCo, and the temperature of the exhaust gas exhausted as Tgo. The steam temperature was 105-108 ° C.

(Experimental Example 1) Effect of Steam Insulation and Steam Consumption Under the conditions shown in FIG. 8 (b), 10 kg (2 kg / min) of bark was charged for 5 minutes and measured. As a result, it was found that when the steam was circulated through the outer shell 33 and heated, the degree of drying was improved and the heating effect of the wood chip W was increased.
As for the steam consumption, when the drain amount for 5 minutes was measured (three times), the average value was 225 g (2.7 kg / h), and the steam production amount of the boiler 80 was 200 kg / h. The rate is as low as 1.4%. Further, the measured value of the inner tube surface temperature was 102 ° C., and it was also found that the vapor was difficult to condense.

(Experimental example 2) Effect of bark input (dry load)
Under the conditions shown in FIG. 8 (c), measurement was carried out for 5 minutes each with three levels of bark input. As a result, even when the input amount of the wood chip W increased by 2 times or 3 times, the water evaporation amount did not increase in proportion thereto. However, the heating effect was almost constant. Therefore, in order to promote the fall of a moisture content, it turned out that adjustment by exhaust gas temperature and the conveyance time (in-pipe residence time) in the screw conveyor 40 is needed.

(Experimental Example 3) Influence of Bark Residence Time in Pipe As shown in FIG. 8D, it was found that an increase in residence time promotes a reduction in moisture content. However, even when 1.5 times from 2 minutes to 3 minutes, the ultimate moisture content was found to be a difference of about 3%. However, the warming effect was enhanced.

  In the above embodiment, an example in which bark is used as the wood chip W has been described. However, the present invention is not necessarily limited to this, and is a wood chip W such as a piece of wood, wood chips, sawdust, etc. Of course, it is also good.

In recent years, there is no demand for coniferous bark discharged from wood processing facilities such as sawmills as compost, and incineration is difficult due to stricter dioxin regulations. For this reason, the disposal costs of bark and sawn timber are increasing and the management of the wood processing industry is under pressure. The woody biomass with a high water content that appears in the wood processing site such as bark has a low bulk specific gravity and therefore has a high transportation cost. Therefore, it is necessary to use it with as little transportation cost as possible. Therefore, it is considered most effective to use it as a fuel for drying wood in wood processing facilities, but in order to burn the bark, in addition to its high water content, combustion ash is produced more than 10 times the wood. Especially in the case of cedar bark, there are many problems such as long fibers and not easy to crush. According to the present invention, since a boiler system using a bark that can be burned by reducing moisture content even with a high moisture content chip can be realized, effective utilization of the bark in a wood processing facility can be realized. It can be used as a technology for using wood chips of any moisture condition as fuel. Consequently, the compression of the improvement and bark waste processing costs of wood utilization yield, improved management of forestry and wood industry by reducing the drying cost, or, and reducing CO ₂ emissions by promoting wood biomass energy use geographically distributed Can contribute.

W Wood chip 1 Feeder 2 Machine stand 3 Hopper
DESCRIPTION OF SYMBOLS 10 Drive chain 11 Conveying member 12 Drive sprocket 14 Supply drive part 15 Bucket 16 Support plate 20 Thickness control mechanism 21 Actuation chain 22 Projection member 23 Actuation sprocket 25 Thickness regulation drive part 30 Drying conveyance apparatus 31 Receiving port 32 Ejection port 33 Outer 34 Outer wall 35 Inner wall S Steam distribution space 38 Heat insulation layer 40 Screw conveyor 41 Rotating shaft P Inner wall center line Q Rotating shaft axis 42 Blade E Transport space Ea Extra space 43 Conveyor drive 45 Steam inlet 46 Steam outlet 47 Steam Supply pipe 48 Adjustment valve 50 Exhaust gas supply pipe 51 Gas inlet 52 Gas outlet 53 Gas injection pipe R Gas injection pipe axis 54 Suction blower 55 Exhaust gas temperature adjustment section 56 Exhaust pipe
57 Exhaust blower 60 Boiler device 61 Combustion chamber 62 Combustion furnace 63 Grate base 63a Ignition burner 64 Fuel supply part 65 Movement mechanism 66 Combustion air supply part 67 Partition wall 68 Supply port 69 Inclined base 80 Boiler (heat exchange part)
81 Gas inlet 82 Gas outlet 83 Heat insulation wall T Chimney device 90 Water pipe portion 91 Lower main water pipe 92 Upper main water pipe 93 First installation water pipe 94 Second installation water pipe 95 Third installation water pipe 96 Fourth installation water pipe F Exhaust space Fa Lower exhaust gas Space Fb Upper exhaust gas space Fc Side exhaust gas space

Claims (9)

A supply device for supplying a predetermined amount of wood chips, a drying transport device for transporting the wood chips supplied by the supply device while drying, and a combustion obtained by burning the wood chips transported by the dry transport device and resulting from the combustion In a boiler system comprising a boiler device that generates steam by heat exchange between gas and water and exhausts the combustion gas after the heat exchange as exhaust gas,
The drying conveyance device has a receiving port for receiving the wood chips supplied from the supply device on one end side, a discharge port for discharging the wood chips on the other end side, and forms a wood chip conveyance space on the inside A cylindrical outer shell, a conveyor that is provided in a transport space formed by the outer shell and transports the wood chips received at the receiving port toward the discharge port, and a conveyor driving unit that drives the conveyor And
The outer shell is provided with a cylindrical outer wall and a cylindrical inner wall that is provided inside the outer wall and forms a steam flow space through which steam can flow. The steam is placed in the steam flow space in the outer shell. A steam inlet for injecting steam and a steam outlet for letting out steam are provided, and a steam supply pipe for feeding a part of the steam generated by the boiler device into the steam circulation space is connected to the steam inlet. The outer shell is provided with a gas inlet for flowing exhaust gas into the transfer space and a gas outlet for discharging exhaust gas, and a part or all of the exhaust gas exhausted from the boiler device is transferred to the gas inlet. A boiler system characterized in that an exhaust gas supply pipe for feeding into a transfer space is provided.   The boiler system according to claim 1, wherein the amount of steam supplied through the steam supply pipeline is 5% or less of the total amount of steam generated by the boiler device.   The boiler system according to claim 2, wherein a heat insulating layer is provided outside the outer wall of the outer shell.   The boiler system according to any one of claims 1 to 3, further comprising an exhaust gas temperature adjusting unit that adjusts the temperature of the exhaust gas by introducing outside air into the exhaust gas supply pipe.   The outer shell is provided with a cylindrical outer wall and a cylindrical inner wall that is provided inside the outer wall and forms a steam flow space through which steam can flow, and the conveyor is formed at the center of the inner wall. A screw conveyor comprising a rotating shaft having an axis in a direction along the line and a spiral blade provided on the outer periphery of the rotating shaft, and the axis of the rotating shaft of the screw conveyor is the center of the inner wall One end of the rotating shaft is pivotally supported on one end of the outer shell and the other end of the rotating shaft is pivotally supported on the other end of the outer shell so as to be eccentrically positioned below the line, and the screw in the conveying space The boiler system according to any one of claims 1 to 4, wherein an extra space is formed in an upper part of the conveyor.   The outer gas inlets are provided on both sides of one end of the outer shell, the exhaust gas supply pipes are configured to the gas inlets, and a straight gas injection pipe having a predetermined length is connected to the gas inlets. The boiler system according to claim 5, wherein the injection pipe is connected so as to be inclined such that a front end side in an injection direction of an axis thereof is directed toward a center line of the inner wall and toward the other end portion side of the outer shell. At least one of a conveying member that is installed between a pair of endless drive chains and conveys a wood chip on the forward path side above the drive chain, and a pair of drive sprockets that span the drive chain A drive drive unit that rotationally drives the drive sprocket and moves the wood chip along the transfer direction toward the receiving port of the dry transfer device by the transfer member,
A thickness regulating mechanism is provided above the carrying member to regulate the carrying thickness of the wood chips carried by the carrying member, and the thickness regulating mechanism is installed between a pair of operating chains and carried by the carrying member. A large number of ridge members whose leading edges abut against the wooden chips, a pair of operating sprockets over which the operating chain is bridged, and the wooden chips conveyed by the conveying members by the ridge members are opposite to the conveying direction. The boiler system according to any one of claims 1 to 6, further comprising a thickness regulating drive unit that rotationally drives at least one of the operating sprockets so as to move in a direction.   The conveying member of the supply device is constituted by a large number of buckets arranged in a line between a pair of endless drive chains and opened on the forward path side of the upper side of the drive chain and released on the front side in the conveyance direction. The boiler system according to claim 7, wherein a support plate for supporting the bucket is provided on an upper outgoing path side.   A combustion chamber that is surrounded by a furnace wall and burns wood chips, and a heat exchange section that is provided above the combustion chamber and that generates steam by exchanging heat between the combustion gas of the wood chips and water. The heat exchanging part is provided with a water pipe part to which water is supplied, and the water pipe part is accommodated and has a gas inlet for exhaust gas from the combustion chamber on the lower side and a gas outlet on the upper side. And a heat insulating wall that forms an exhaust gas space through which the exhaust gas circulates, and the water pipe portion is bent into a substantially rectangular shape with one side and the other side facing the one side, and a water supply port for water is provided. A lower main water pipe having an upper side of the lower main water pipe corresponding to the lower main water pipe, and having a side and another side opposite to the side and bent into a substantially rectangular shape. An upper main water pipe having a steam outlet, and one side of the lower main water pipe and the other side of the upper main water pipe A first erected water pipe having a plurality of branch pipes that are installed in a row and connected to each other by a connecting plate, the other side of the lower main water pipe, and one side of the upper main water pipe A second erected water pipe having a plurality of branch pipes installed in a row in between and adjacent branch pipes connected by a connecting plate, one side of the lower main water pipe, and one side of the upper main water pipe A third installed water pipe having a plurality of branch pipes installed in a row between them and adjacent branch pipes connected by a connecting plate, the other side of the lower main water pipe, and the upper main water pipe A plurality of branch pipes arranged in a row with the other side and having a plurality of branch pipes connected to each other by a connecting plate, the first installation water pipe The lower exhaust gas space surrounded by the lower side of the first and the second installed water pipe, the upper side surrounded by the upper side of the first installed water pipe and the upper side of the second installed water pipe A pair of side exhaust gas spaces surrounded by the exhaust gas space, the first erection water pipe, the second erection water pipe and the third erection water pipe and surrounded by the first erection water pipe, the second erection water pipe and the fourth erection water pipe are formed. The exhaust gas space is formed so that the path from the gas inlet to the gas outlet of the exhaust gas from the combustion chamber is in the order of the lower exhaust gas space, the side exhaust gas space, and the upper exhaust gas space. 8. The boiler system according to any one of the above.

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