JP3577483B2 - Wood drying equipment and low temperature drying method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wood drying apparatus and a low-temperature drying apparatus for low-temperature drying of larch wood and softwood such as spruce and fir that are piled in a large larch log house having a greenhouse structure by using local energy such as hot spring heat and solar heat in combination. About the method.
[0002]
[Prior art]
Conventionally, for drying of larch wood and softwood such as Scots pine and Abies sachalinen, a rapid drying method of 100 ° C or higher and high temperature by electric dehumidification drying (FIG. 4) or steam heating drying (FIG. 5) is used. In this method, larch wood is particularly vulnerable due to twisting and fine cracking, and has been considered only for low-value uses such as packing materials, pallet materials, and civil engineering materials, and has not been possible to use as building materials.
In order to increase the added value of larch wood as a building material, it is necessary to dry to a moisture content of 50% to 20% or less by low-temperature artificial drying at 80 ° C or less to suppress the occurrence of twisting and cracking.
However, as the time required for drying increases, fuel costs, electricity costs, and personnel costs, which are heat sources, increase, the value of lumber products increases, and it is difficult to compete with external materials.
[0003]
[Problems to be solved by the invention]
Using the abundant hot spring heat and solar heat in the Hokkaido region as a heat source, low-temperature drying of larch wood by combined use of local natural energy, mass-producing low-cost larch dried wood, and trying to utilize it as building material , without discharging the CO _2, and an object thereof is to provide a timber drying apparatus and cold drying method with consideration to the environment.
[0004]
[Means for Solving the Problems]
Therefore, the wood drying apparatus of the present invention builds a large space building using a composite truss material composed of larch logs and steel angles for a frame, and covers the roof and side walls of the building with a transparent sheet, and a larch of greenhouse structure. A log house is constructed, and a large box-shaped bag made of a transparent sheet is hung from the ceiling like a mosquito net inside the house to form a drying room, and a circulation fan is provided on the ceiling and the bottom of the drying room, and the drying room is provided. A fan with a heat exchanger and a floor warming panel.
Further, the low-temperature drying method of the present invention is to produce a large-sized house using a composite truss material composed of a larch log and a steel angle as a frame, and cover the roof and side walls of the house with a transparent sheet, and a larch having a greenhouse structure. A log house is constructed, and a large box-shaped bag made of a transparent sheet is hung from the ceiling like a mosquito net inside the house to form a drying room, and a circulation fan is provided on the ceiling and the bottom of the drying room, and the drying room is provided. A wood drying device with a fan with a heat exchanger and a floor warming panel is formed in it, and larch, spruce, fir and other coniferous wood are piled inside the drying room of the wood drying device, and the heat source is supplied with hot spring heat. the solar heat is obtained by complex use.
Furthermore, the low-temperature drying method of the present invention is based on hot air drying using a fan with a heat exchanger using hot spring heat, radiation drying and convection drying using a floor warm panel, and passive use of solar heat using the greenhouse effect. It is a combination of hot air drying and radiation drying.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a wood drying apparatus according to the present invention will be described with reference to the drawings.
First, as shown in FIG. 1, a large-space house is constructed using a truss structural material composed of a larch log 1 and an angle material 2 as a frame, and is covered with a transparent sheet 3 to construct a greenhouse larch log house. .
Inside the larch log house, a box-shaped bag 4 made of transparent sheet 3 (partially opaque sheet) is suspended from the ceiling of the house like a mosquito net with a hanging rod 11 to form a large drying room 5 and piled in the room. The pile material 6 is arranged at several places.
A floor warm panel 7 is laid on the floor (some walls are used) for radiation drying, a large circulating fan 8 for hot air drying is provided on the ceiling of the drying room 5, a fan 9 with a heat exchanger is provided at an appropriate floor height, A small circulation fan 10 is installed at the bottom of the drying chamber 5.
[0006]
Next, the operation of the wood drying apparatus of the present invention will be described with reference to FIG. Normally, the air in the drying room 5 is blown out toward the ceiling of the larch log house by the large circulation fan 8 (forward rotation) on the ceiling of the drying room 5, and the air that has fallen down the back of the cabin is discharged between the house and the drying room 5. It is sent to the bottom of the drying chamber 5 through both sides, and is again taken into the drying chamber 5 by the small circulating fan 10 to form a circulating flow of warm air and perform low-temperature hot-air drying.
During the daytime sunshine, the hot air heated by the solar heat on the back of the larch log house is drawn directly into the room from the ceiling of the drying room 5 by the large circulation fan 8 (reverse rotation) and sprayed onto the pile material 6, and at the same time heat exchanger With the fan 9 attached, air is blown to the pile material 6 in the drying chamber 5 to perform medium-temperature hot-air drying.
At this time, the small circulation fan 10 at the bottom of the drying chamber 5 is stopped, and the air in the drying chamber 5 is sent out from the lower end of the bottom to both sides of the house to form a reverse circulation flow of warm air.
A ventilation port (not shown) is provided at an appropriate place of the larch log house in the circulation path of these air, and the hot air that has become wet air by dehumidifying and drying the pile material 6 is partially discharged to the outside. Introduce fresh dry air.
The hot spring heat is exchanged for antifreeze and sent to the floor warm panel 7 and the fan 9 with the heat exchanger, and radiation drying and convection drying by the floor warm panel 7 and hot air drying by the fan 9 with the heat exchanger are always performed. The whole equipment is called larch log drying plant).
The principle of drying is to provide a large larch log house with a greenhouse structure in the shed of the drying room 5 based on passive use of solar heat, and to use low-temperature heat together with this to promote low-temperature drying.
[0007]
【Example】
(Example 1)
Example 1 of a larch drying plant using larch test materials will be described in detail (see FIG. 1).
(1) Larch log house; size (width 14.4m, depth 18.0m, eave height 5.0m (building height 8.5m)), roof and side walls covered with transparent sheet 3 to form a greenhouse structure and keep airtight . (Ventilation vents in place for dehumidification ventilation).
(2) Drying room 5: Transparent sheet (partially opaque) structure of size (10.0 mW x 14.0 mL x 5.0 mH) and suspended from ceiling on ceiling hanging rod 11 like a mosquito net.
(3) Heat collecting area: Same as 140 m ² (= 10.0 mx 14.0 m) in 5 drying rooms.
(4) Radiation panel; a hot water floor warm panel 7 having a drying room 5 floor area of 120 m ² (= 10.0 mx 12.0 m) is laid (it can be attached to the inside of the side wall).
(5) Large heat exchanger; two heat exchangers from hot spring heat to antifreeze hot water.
(6) Blowers (fans): Fans 9 (10 units) with heat exchangers, large circulation fans 8 (5 units), and small circulation fans 10 (10 units).
(7) Measuring instruments: pyranometer, thermometer, (including air temperature and room temperature), calorimeter, air flow meter, hygrometer, etc., and a set of data capture processor.
(8) Complete system control device.
(9) Floor warm panel 7, circulating pump, piping and valves.
(10) Floor and side walls; made of concrete or asphalt and heat-insulated.
In the larch test material, six larch piles 6 (bulk volume 3.0 mW x 4.0 mL x 3.0 mH) are arranged inside the drying room 5, and the period required for drying by a drying plant of this scale is as follows. It is about 7 to 10 days in summer and about 10 to 15 days in winter.
[0008]
Hot spring heat source: An example of a system flow design using a hot spring with a flow rate of 100 L / min and a temperature of 53 ° C. as a heat source of the present system.
1. DC system flow; loss is not taken into account in the temperature display of FIG.
2. Split system flow; loss is not considered in the temperature display of FIG.
An example of a thermal calculation simulation of the above system is shown below, divided into a DC type and a shunt type.
[0009]
(Example 2)
A second embodiment in which a hot spring heat source is piped in series with a front heat exchanger and a rear heat exchanger will be described in detail (see FIG. 2).
A. DC type system (considering loss in Fig. 2)
1. Hot spring heat radiation (flow rate x temperature difference)
(1) Fan 9 with heat exchanger (hot air drying)
Primary heat exchanger primary side; hot spring flow rate G ₁ = 100 L / min, 53 ° C. → 48 ° C., ΔT ₁ = 5 ° C., η _F1 = 0.9
Secondary heat exchanger side; antifreeze liquid flow rate G ₂ = 50 L / min, 52 ° C. → 42 ° C., ΔT ₂ = 10 ° C., η _F2 = 0.81
_{Q F1 = η F1 · c ·} G 1 · ΔT 1 = 0.9 × 1.0 × 100 × 5 = 450kcal / min = 648Mcal / day _{Q F2 = η F2 · c ·} G 2 · ΔT 2 = 0.81 × 1.0 × 50 × 10 = 405 kcal / min = 583 Mcal / pre-stage heat exchanger efficiency Q _F2 / Q _F1 = 583/648 = 0.90
(2) Floor warm panel 7 (radiation drying + convection drying)
On the downstream side of the primary heat exchanger; hot spring flow rate G ₁ ′ = 100 L / min, 48 ° C. → 43 ° C., ΔT ₁ ′ = 5 ° C., η _p1 = 0.9
Secondary heat exchanger secondary side; antifreeze liquid flow rate G ₂ ′ = 50 L / min, 47 ° C. → 37 ° C., ΔT ₂ ′ = 10 ° C., η _p2 = 0.77
Q _p1 = η _p1 · G · ₁ ′ · ΔT ₁ ′ = 0.9 × 1.0 × 100 × 5 = 450 kcal / min = 648 Mcal / day Q _p2 = η _p2 · c · G ₂ ′ · ΔT ₂ ′ = 0.77 × 1.0 × 50 × 10 = 385 kcal / min = 554 Mcal / day post-stage heat exchanger efficiency Q _p2 / Q _p1 = 554/648 = 0.85
2. Floor warming panel 7 Heat radiation (1) Radiation radiation (radiation drying)
Panel area _AP = 120 m ² , T ₁ = 47 ° C., T ₂ = 37 ° C., T _m = 42 ° C.
Q _R12 = 4.88 {[(273 + 42) / 100] ⁴ -[(273 + 32) / 100] ⁴ } × 1.0 × 120 = 585.6 × (98.5-86.5) = 7027 kcal / hour = 169 Mcal / day (2) Convection heat release (convection drying)
Floor warm panel 7 total heat dissipation Q _pT = Q _p2 = 554 kcal / day floor warm panel 7 convection heat dissipation Q _pC = Q _p2 -Q _R12 = 554-169 = 385 Mcal / day convection heat dissipation Q _pC / Q _PT = 385 / 554 = 0.70
Radiation radiation rate Q _R12 / Q _PT = 0.30
3. Annual average solar radiation in the solar hot Ashoro-cho J = 3.38 kWh / m ² d = 2907 kcal / m ² d
Solar heat collection area A _C (= 5 drying rooms) = 140m ²
Sheet transmittance τ _S = 0.8
Frame material porosity τ _w = 0.8
Incident solar radiation _{Q S = J · τ S ·} τ w · A C = 2907 × 0.8 × 0.8 × 140 = 260Mcal / day Onsen heat radiation amount (= secondary total heat radiation _{amount) Q F2 + Q P2 = 583} + 554 = solar percentage 1137Mcal / day Onsen heat discharge _{Q S / (Q F2 + Q} P2) = 260/1137 = 0.229 ≒ 1 / 4.4
4. Total calorific value of hot spring calorie + solar calorie = 1137 + 260 = 1397 Mcal / day
(Example 3)
Example 3 in which a hot spring heat source is piped in parallel to the first heat exchanger and the second heat exchanger will be described in detail (see FIG. 3).
B. Split-flow system (considering loss in Fig. 3)
1. Hot spring heat release (flow rate x temperature difference)
(1) Fan 9 with heat exchanger (hot air drying)
No. 1 heat exchanger primary side; hot spring flow rate G ₁ = 50 L / min, 53 ° C. → 43 ° C., ΔT ₁ = 10 ° C., η _F1 = 0.9
No. 1 heat exchanger secondary side; antifreeze liquid flow rate G ₂ = 50 L / min, 52 ° C. → 42 ° C., ΔT ₂ = 10 ° C., η _F1 = 0.81
Q _F1 = η _F1 · c · G ₁ · ΔT ₁ = 0.9 × 1.0 × 50 × 10 = 450 kcal / min = 648 Mcal / day Q _F2 = η _F2 · c · G ₂ · ΔT ₂ = 0.81 × 1.0 × 50 × 10 = 405 kcal / min = 583 Mcal / day No. 1 heat exchanger efficiency Q _F2 / Q _F1 = 583/648 = 0.90
(2) Floor warm panel 7 (radiation drying + convection drying)
No. 2 heat exchanger primary side; hot spring flow rate G ₁ ′ = 50 L / min, 43 ° C. → 43 ° C., ΔT ₁ ′ = 10 ° C., η _p1 = 0.9
No. 2 heat exchanger secondary side; antifreeze flow rate G ₂ ′ = 50 L / min, 47 ° C. → 37 ° C., ΔT ₂ ′ = 10 ° C., η _p2 = 0.77
Q _p1 = η _p1 · c · G ₁ ′ · ΔT ₁ ′ = 0.9 × 1.0 × 50 × 10 = 450 kcal / min = 648 Mcal / day Q _p2 = η _p2 · c · G ₂ ′ · ΔT ₂ ′ = 0.77 × 1.0 × 50 × 10 = 385 kcal / min = 554 Mcal / day No.2 heat exchanger efficiency Q _p2 / Q _p1 = 554/648 = 0.85
2. Floor warming panel 7 Heat radiation (1) Radiation radiation (radiation drying)
Panel area A _P = 120 m ² , T ₁ = 52 ° C., T ₂ = 42 ° C., T _m = 47 ° C.
Q _R12 = 4.88 {[(273 + 47) / 100] ⁴ -[(273 + 37) / 100] ⁴ } × 1.0 × 120 = 585.6 × (105−92) = 7613 kcal / hour = 183 Mcal / day ( 2) Convection heat dissipation (convection drying)
Floor warm panel 7 total heat dissipation Q _pT = Q _p2 = 554 kcal / day floor warm panel 7 convection heat dissipation Q _pC = Q _p2 -Q _R12 = 554-183 = 371 Mcal / day convection heat dissipation rate Q _pC / Q _PT = 371 / 554 = 0.67
Radiation radiation rate Q _R12 / Q _PT = 0.33
3. Annual average solar radiation in the solar hot Ashoro-cho J = 3.38 kWh / m ² d = 2907 kcal / m ² d
Solar heat collection area A _C (= 5 drying rooms) = 140m ²
Sheet transmittance τ _S = 0.8
Frame material porosity τ _w = 0.8
Incident solar radiation _{Q S = J · τ S ·} τ w · A C = 2907 × 0.8 × 0.8 × 140 = 260Mcal / day Onsen heat radiation amount (= secondary total heat radiation _{amount) Q F2 + Q P2 = 583} + 554 = solar percentage 1137Mcal / day Onsen heat discharge _{Q S / (Q F2 + Q} P2) = 260/1137 = 0.229 ≒ 1 / 4.4
4. As a result of the thermal design of the total calorific value of hot spring calorific value + solar calorific value = 1137 + 260 = 1397 Mcal / day or more, there is no difference between the direct current type and the split flow type. The higher the heat and the higher the amount of radiation heat, it was found that good conditions for drying were created.
Therefore, the split flow type is slightly more advantageous.
[0011]
Next, the amount of heat required to dry the larch wood (from 50% to 20%) is calculated.
1) Heat of vaporization of water (heat of evaporation)
582.8 kcal / kg @ 583 kcal / kg at 25 ° C
539.8 kcal / kg @ 540 kcal / kg at 100 ° C
Average 562kcal / kg
2) bulk volume of the volume-weight桟積seen material Yaku material = 3.0 × 4.0 × 3.0 = 36m 3
Actual volume = bulk volume × 0.6 = 36 × 0.6 = 21.6 m ³
Test material density: The density of the larch raw material is assumed to be 600 kg / m ³ by estimating from the values of pine (377 kg / m ³ ) and cedar (341 kg / m ³ ) of the dried material (30 ° C.).
Mass of one pile material = actual volume × density = 21.6 m ³ × 600 kg / m ³ ≒ 13000 kg / loading water removal amount = 13000 kg × (0.5−0.2) = 3900 kg / loading heat of evaporation = 3900 kg × 562 kcal / kg = 2192 Mcal / total heat required for product drying (latent heat of evaporation) = 2192 Mcal × 6 ≒ 13150 Mcal / 6 The required heat per day assuming that the product is dried in an average of 10 days = 1315 Mcal / day The above Examples 2 and Examples 3, the total amount of heat that can be obtained by the wood drying device is 1397 Mcal / day, while the amount of heat required for drying is 1315 Mcal / day. Therefore, the larch is dried using the wood drying device for a predetermined period (an average of 10 days per year). Is possible.
[0012]
【The invention's effect】
In this manner, the wood drying apparatus of the present invention performs low-temperature drying of larch wood using combined use of local natural energy, using abundant hot spring heat and solar heat as a heat source in the Hokkaido region, and provides low-cost larch drying at low cost. Materials can be mass-produced and used as building materials.
Furthermore, low temperature drying process of the present invention, spruce not limited to larch, can be applied to softwood, such as fir, also without the use of fossil fuels as a side effect, therefore without discharging the CO _2, the environmental It has been considered.
By using solid larch obtained by low-temperature drying for building materials, it is possible to solve the sick house problem caused by the use of new building materials.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a wood drying device of the present invention.
FIG. 2 is a DC system flow chart.
FIG. 3 is a flow diagram of a split flow system.
FIG. 4 is a schematic configuration diagram of a conventional electric dehumidifier dryer.
FIG. 5 is a schematic configuration diagram of a conventional steam heating type drying apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Larch log 2 Angle material 3 Transparent sheet 4 Box-shaped bag 5 Drying room 6 Piling material 7 Floor warm panel 8 Large circulation fan 9 Fan with heat exchanger 10 Small circulation fan 11 Ceiling hanging rod 12 Wind direction guide

Claims (3)

Building a large space house using a composite truss material consisting of larch logs and steel angles for the frame, building a larch log house with a greenhouse structure by covering the roof and side walls of the house with transparent sheets, and inside the house A large box-shaped bag made of a transparent sheet is hung from the ceiling like a mosquito net to form a drying room, a circulation fan is provided on the ceiling and hem of the drying room, and a fan with a heat exchanger and a floor warm panel are provided in the drying room. A wood drying device, which is arranged. Building a large space house using a composite truss material consisting of larch logs and steel angles for the frame, and covering the roof and side walls of the house with transparent sheets to build a larch log house with a greenhouse structure, and the interior of the house A large box-shaped bag made of a transparent sheet is hung from the ceiling like a mosquito net to form a drying room, a circulation fan is provided on the ceiling and hem of the drying room, and a fan with a heat exchanger and a floor warm panel are provided in the drying room. the forming a timber drying apparatus disposed, the wood drying apparatus larch and spruce in the drying chamber, sewing machine桟積softwood material such as fir, low temperature drying method that combines use of hot springs and the sun heat to a heat source. Combined use of hot-air drying using a fan with a heat exchanger using hot spring heat, radiation drying and convection drying using a floor warm panel, and hot-air drying and radiation drying using passive solar heat using the greenhouse effect. The low-temperature drying method according to claim 2.

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