KR101975653B1 - Method for producing green wood drying-heat treatment using superheated stream - Google Patents

Abstract

The present invention discloses a raw material drying-heat treatment process. The raw material drying-heat treatment process according to an embodiment of the present invention includes preparing and heating a raw material; A first drying-heat treatment step of performing heat treatment to remove free water in the raw material using superheated steam; A secondary drying-heat treatment step of removing the coupling water in the wood by using the superheated water vapor and performing a heat treatment at a higher temperature than the primary drying-heat treatment step; A concentrated heat treatment step of performing heat treatment at a maximum temperature of the internal temperature of the secondary drying-heat-treated wood having reached an equilibrium moisture content using the superheated steam; And a cooling step of cooling the concentrated heat treated wood, wherein the primary drying-heat treatment step, the secondary drying-heat treatment step, and the concentrated heat treatment step have a superheated water vapor temperature of 140 to 260 캜 and a superheated water vapor temperature of 4 to 400 atm And is advanced at superheated water vapor pressure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for producing a high-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw material drying-heat treatment process, and more particularly, to a process of drying-heat-treating a raw material using superheated steam.

The interior of the wood contains a large amount of moisture. These woods have different shrinkage or swelling ratios depending on the longitudinal and transverse directions, and because of the difference in shrinkage or swelling ratio, the drying process of the wood, the heat treatment process, Cracks, twisting or dimensional deformation may occur during use.

Therefore, in order to prevent such cracking, twisting or dimensional instability of the wood, when the wood is processed, the process of drying the wood is carried out before the processing.

In general, when the wood is heat-treated at a temperature at which the main components (cellulose, hemicellulose and lignin) are changed, the shrinking expansion of the wood is reduced and the dimensions are stabilized. The color changes into a dark brown color such as chocolate, There is a characteristic that natural decay of wood is prevented.

When the wood is heat treated, the wood has the advantages of increasing the dimensional stability by decreasing the equilibrium moisture content, improving the internal post-performance and uniformizing the coloration of uneven surface.

The conventional wood heat treatment method uses wood dried at a moisture content of about 10% to 15% in order to prevent deformation such as internal check or distortion which may occur during heat treatment. In this case, since the drying and the heat treatment process are performed by different processes in different apparatuses, it takes a long time to produce the heat-treated wood and there is a drawback that the energy consumption for the heat-treated wood production is large.

In addition, the heat treatment method using heat has a risk of fire due to high temperature heat, and the heat treatment method using other heat bodies other than heat may be costly or accompanied by changes in the physical properties of the wood by the medium. Particularly, since most decomposition products generated from wood by heat treatment at high temperature are burned off on the surface of the heat treatment apparatus, they can not be recovered and can not be reused.

Korean Patent Registration No. 10-1649095, "Integrated Wood Drying and Carbonization Device and Method Using Microwave" Korean Patent Laid-Open Publication No. 10-2015-0120028, " Heat Treatment Method of Wood and Woody Material with Increased Durability &

The present invention provides a raw material drying-heat treatment process using superheated steam.

Since the superheated water vapor is used as a heat transfer medium for heat treatment, drying and heat treatment are performed at the same time. Therefore, compared to the method of treating the drying and the heat treatment by separate processes, the energy consumption is small and the heat treatment is performed in a state in which oxygen is excluded To reduce the risk of fire.

Also, a large amount of decomposition products produced by the heat treatment are present in the superheated steam used as a heat transfer medium, and they are recovered and reused.

The raw material drying-heat treatment process according to an embodiment of the present invention includes preparing and heating a raw material; A first drying-heat treatment step of performing heat treatment to remove free water in the raw material using superheated steam; A secondary drying-heat treatment step of removing the coupling water in the wood by using the superheated water vapor and performing a heat treatment at a higher temperature than the primary drying-heat treatment step; A concentrated heat treatment step of performing heat treatment at a maximum temperature of the internal temperature of the secondary drying-heat-treated wood having reached an equilibrium moisture content using the superheated steam; And a cooling step of cooling the concentrated heat treated wood, wherein the primary drying-heat treatment step, the secondary drying-heat treatment step, and the concentrated heat treatment step have a superheated water vapor temperature of 140 to 260 캜 and a superheated water vapor temperature of 4 to 400 atm It proceeds at superheated water vapor pressure.

The primary drying-heat treatment step, the secondary drying-heat treatment step and the concentrated heat treatment step may be carried out at a superheated steam temperature of 260 ° C and a superheated steam pressure of 5 atm.

The step of preparing and heating the raw material may proceed until the internal temperature of the raw material reaches the boiling point of water at the target pressure condition.

The primary drying-heat treatment step may be a period in which the internal temperature of the wood maintains the boiling point of water at the target pressure condition.

The secondary drying-heat treatment step may be continued until the internal temperature of the wood starts to rise again from the boiling point of water at the target pressure condition and the internal temperature of the wood approaches the maximum temperature.

The concentrated heat treatment step may be a period in which the internal temperature of the wood maintains a maximum temperature.

Wherein the centralized heat treatment step determines the treatment time according to the use of the dry-heat treated wood, and the treatment time monitors the internal temperature of the wood in real time during the concentrated heat treatment step, Can be determined as the elapsed time from the point of time close to the temperature to the point of time when the lumped heat treatment step ends.

The primary drying-heat treatment step and the secondary drying-heat treatment step may proceed inside a sealed reactor.

The cooling step can be slowly cooled at a rate of -20 ° C / hour or less in the reactor where the process has ended.

According to the embodiment of the present invention, since the superheated water vapor is used as a heat transfer medium for heat treatment, drying and heat treatment are performed at the same time. Therefore, compared to a method of treating drying and heat treatment by separate processes, Since the heat treatment is performed, the risk of fire can be reduced.

According to an embodiment of the present invention, a large amount of decomposition products produced by the heat treatment is present in the superheated steam used as a heat transfer medium, and can be recovered and reused.

According to the embodiment of the present invention, by simultaneously performing the drying treatment and the heat treatment of the raw material, the strength of the wood can be increased and the shrinkage rate can be reduced.

According to the embodiment of the present invention, the drying and the heat treatment of the raw material are performed at the same time, so that it is possible to produce a good quality wood material, and the productivity and work efficiency of the wood can be greatly improved.

According to the embodiment of the present invention, it is possible to suppress the rippling of the wood by drying-heat-treating the wood using superheated water vapor

According to the embodiment of the present invention, it is possible to obtain a wooden material having a desired color tone by drying-heat-treating the wood using superheated water vapor, and also to obtain a rosin removal effect in pine and larch.

FIG. 1 is a flowchart illustrating a raw material drying-heat treatment process according to an embodiment of the present invention.
FIG. 2 is a graph illustrating a process of drying and heating a raw material according to an embodiment of the present invention.
3 is a cross-sectional view of a wood in a raw material state and a wood subjected to a raw material drying-heat treatment process according to Example 1 of the present invention.
4 is a graph showing the equilibrium moisture content of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention.
FIG. 5 is a graph showing the compressive strength parallel to the grain of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention.
FIG. 6 is a graph showing the mass loss rate and deterioration rate of the brown rot fungi of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention depression rate.
FIG. 7 is a graph showing the mass loss rate and deterioration rate of white rot fungi of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention depression rate.
FIG. 8 is a graph showing the total volume shrinkage of wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

As used herein, the terms "embodiment," "example," "side," "example," and the like should be construed as advantageous or advantageous over any other aspect or design It does not.

Also, the term 'or' implies an inclusive or 'inclusive' rather than an exclusive or 'exclusive'. That is, unless expressly stated otherwise or clear from the context, the expression 'x uses a or b' means any of the natural inclusive permutations.

Also, the phrase " a " or " an ", as used in the specification and claims, unless the context clearly dictates otherwise, or to the singular form, .

It will also be understood that when an element such as a film, layer, region, configuration request, etc. is referred to as being "on" or "on" another element, And the like are included.

FIG. 1 is a flowchart illustrating a raw material drying-heat treatment process according to an embodiment of the present invention.

Referring to FIG. 1, a raw material drying-heat treatment process according to an embodiment of the present invention includes preparing and heating a raw material (S110), performing a primary drying-heat treatment to remove free water in the raw material using superheated steam (S130) for removing the coupling water in the wood by using superheated steam, performing a second drying-heat treatment step (S130) for performing heat treatment at a higher temperature than the first drying-heat treatment step (S130) Secondary drying - a concentrated heat treatment step (S140) for heat treating at the highest temperature of the internal temperature of the heat treated wood and a cooling step (S150) for cooling the concentrated heat treated wood.

Also, the first drying-heat treatment step S120, the second drying-heat treatment step S130 and the concentrated heat treatment step S140 of the raw material drying-heat treatment step according to the embodiment of the present invention are performed at a temperature of 140 ° C. to 260 ° C., Temperature and superheated water vapor pressure of 4 atm to 400 atm.

In addition, the first drying-heat treatment step (S120), the second drying-heat treatment step (S130), and the concentrated heat treatment step (S140) may be heat-treated using superheated water vapor.

Superheated water vapor used in wood heat treatment (primary drying-heat treatment (S120), secondary drying-heat treatment (S130) and concentrated heat treatment (S140)) refers to water vapor having a temperature higher than the boiling point. The process has many advantages such as high energy efficiency, fast drying speed, low risk of fire, and easy combination with other drying processes.

Drying using superheated water vapor - The heat treatment process has various advantages because it uses air that has been excluded from the air as a drying medium and proceeds in a closed space.

The most important advantage is that it can be used for electric power generation by using discharged steam or energy efficiency can be improved by recycling waste steam as it is. Since the discharged water vapor has a low specific enthalpy, it is possible to recycle most of the latent heat supplied to the superheated water vapor if the waste water vapor is mechanically or thermally-compressed to increase the boiling water vapor .

In addition, since the resistance of moisture evaporated from the raw material to diffusion into water vapor is much smaller than that of kiln drying, the drying speed at the surface can be greatly improved above the inversion temperature. In addition, in the drying-heat treatment process using the superheated water vapor, surface hardening phenomenon does not occur due to the rapid drying of the surface due to the absence of an outer layer which is difficult to permeate moisture.

Therefore, the occurrence of dry defects such as segregation occurring during drying or heat treatment is reduced, and oxidation and combustion reaction are not caused because oxygen is not present in the reactor, thereby suppressing the deformation of the raw wood by oxidation And there is no risk of fire or explosion.

In addition, since there is no oxygen in the reactor, it can exhibit a germicidal effect against aerobic bacteria that deterioration of wood.

When the microorganisms in the wood add the wood, the physical and mechanical properties of the wood are changed accordingly. Changes in properties include not only strength but also density, hygroscopicity, conductivity, acoustics, calorie, and dimensions.

In other words, microorganisms (rot fungi) decompose certain components of the wood cell wall, so that the weight of the wood which is suffering from the boiling is reduced. These rotting fungi include brown rot fungi and white rot fungi.

That is, the wood-drying-heat-treated wood according to the embodiment of the present invention reduces the mass reduction rate of the brown rot fungi or the white rot fungi, thereby preventing the degradation of strength during use of the wood.

Further, in the raw material drying-heat treatment process according to the embodiment of the present invention, the compressive strength parallel to the grain of the raw wood can be improved by using superheated water vapor.

'Raw material' means wood that maintains a water content above the fiber saturation point without any treatment (drying, heat treatment or chemical treatment). However, in order to explain the various physical properties of wood (shrinkage, strength, resistance to rot fungi and coloration) in the case of processed raw materials such as drying, heat treatment or chemical treatment, the word 'raw material' Is used.

First, the preparation and heating of the raw material are performed (S110).

The raw material can be cedar, pine, lily, palm, lizard, pine, pine or larch.

In the step of preparing and heating the raw material (S110), when the prepared raw material is heated, the internal temperature of the wood is increased to the boiling point of the water at the target pressure of the superheated steam.

That is, the step of preparing and heating the raw material (S110) may be determined from the time when the raw material is prepared and the heating is started until the internal temperature of the wood reaches the boiling point of water at the target pressure condition.

At this time, the boiling point of water may be 140 to 260 캜, and the target pressure may be 4 to 400 atm.

Thus, the internal temperature of the wood may be 140 ° C to 260 ° C.

For example, the step of preparing and heating the raw material (S110) may be determined up to a point at which the boiling point of water at 5 atm reaches a range of 150 to 160 캜, when the target pressure is 5 atm.

At a saturation pressure of 400atm, which is a saturation pressure of 4atm to 260C.

(S130) for removing the free water in the raw material and performing heat treatment at a low temperature (S120) and a secondary drying-heat treatment step (S130) for removing bonding water in the wood and performing heat treatment at a higher temperature than the primary drying- ).

The raw material drying-heat treatment process according to an embodiment of the present invention is divided into a first drying-heat treatment step (S120), a second drying-heat treatment step (S130), and a concentrated heat treatment step (S140) in which drying and heat treatment are simultaneously performed This is not arbitrarily adjusted, but is formed naturally in the process of drying the wood.

First, the same components of the primary drying-heat treatment step (S120), the secondary drying-heat treatment step (S130) and the concentrated heat treatment step (S140) will be described first, and then each step will be separately described below .

The first drying-heat treatment step S120, the second drying-heat treatment step S130 and the concentrated heat treatment step S140 may be performed at a superheated water vapor temperature of 140 ° C to 260 ° C, If the temperature of the superheated steam is less than 140 ° C in the secondary drying-heat treatment step (S130) and the concentrated heat treatment step (S140), heat treatment is not performed because there is no change in the main component of the wood. When the temperature exceeds 260 ° C, cellulose decomposes, There is a problem that the strength can not be maintained.

The primary drying-heat treatment step (S120), the secondary drying-heat treatment step (S130), and the concentrated heat treatment step (S140) may proceed in the saturation pressure range of the superheated steam. That is, at a saturation pressure of 400atm, which is a saturated pressure of 4atm to 260C, which is a saturation pressure of 140C.

Preferably, the primary drying-heat treatment step (S120), the secondary drying-heat treatment step (S130) and the concentrated heat treatment step (S140) can proceed at a superheated steam temperature of 260 ° C and superheated steam pressure of 5 atm, The maximum temperature inside the wood is 220 ° C.

In addition, the pressure in the first drying-heat treatment step (S120), the second drying-heat treatment step (S130), and the concentrated heat treatment step (S140) may be increased as the moisture introduced into the reactor evaporates.

The first drying-heat treatment step S120, the second drying-heat treatment step S130, and the concentrated heat treatment step S140 can perform constant rate period of drying and reuse of water vapor depending on the pressure of the superheated steam. It becomes.

In addition, the conditions of the pressure to be considered according to the purpose of the drying-heat treatment can be classified into atmospheric pressure, atmospheric pressure, and subatmospheric pressure. Pressure above atmospheric pressure may be used if energy recovery is important, and subatmospheric pressure may be used if the product is sensitive to temperature. Preferably, the drying-heat treatment with superheated steam may proceed above ambient pressure.

The primary drying-heat treatment step (S120), the secondary drying-heat treatment step (S130) and the concentrated heat treatment step (S140) may proceed inside the sealed reactor.

That is, in the first drying-heat treatment step (S120), the second drying-heat treatment step (S130) and the concentrated heat treatment step (S140), superheated water vapor is used as a heat transfer medium of the raw material so that the environment inside the reactor is oxygen- .

The primary drying-heat treatment step S120, the secondary drying-heat treatment step S130 and the concentrated heat treatment step S140 can maintain the temperature and pressure of the superheated steam at a constant level during the heat treatment, It is possible to suppress the occurrence of the splitting on the surface and inside of the wood material in the step S120, the secondary drying-heat treatment step S130 and the concentrated heat treatment step S140.

The raw material drying-heat treatment process according to the embodiment of the present invention can increase the strength of the wood and reduce the shrinkage rate by simultaneously performing the drying treatment and the heat treatment of the raw material.

When heat is applied at a high temperature (160 ° C to 260 ° C), thermochemical changes in the wood reduce the number of hydrophilic functional groups (-OH groups) in the main constituents (cellulose, hemicellulose and lignin) constituting the wood. As a result, the thermally treated wood has increased hydrophobicity compared to the untreated material, and the water content change due to changes in the environmental conditions (temperature and relative humidity) is reduced. Therefore, the shrinkage rate and the expansion rate decrease with the change of moisture.

 In the case of the raw material drying-heat treatment process according to the embodiment of the present invention, the thermal hydrolysis of the wood is promoted by a large amount of water vapor, and the heat treatment effect is higher. Therefore, heat (high temperature air containing nitrogen and oxygen It is possible to further reduce the shrinkage rate and the expansion ratio.

Also, when heat treating the wood, if it is desired to have high strength performance of the wood, the wood should be subjected to heat treatment at a low temperature, and if the strength performance of the wood is not important, it is desirable to heat the wood at a higher temperature.

The primary drying-heat treatment step S120, the secondary drying-heat treatment step S130 and the concentrated heat treatment step S140 can be classified according to the internal temperature change of the wood during the superheated steam drying-heat treatment process, The internal temperature change can be confirmed by monitoring the real-time temperature change through a temperature sensor inserted inside the wood.

The primary drying-heat treatment step (S120) can be determined as the interval during which the freezing water in the wood is removed and the internal temperature of the wood maintains the boiling point of water at the target pressure condition.

At this time, the boiling point of water may be 140 to 260 캜, and the target pressure may be 4 to 400 atm.

Preferably, in the raw material drying-heat treatment process according to the embodiment of the present invention, since the target temperature of the steam and the target pressure of the steam are set at 260 ° C. and 5 atm simultaneously with the start of the process, S120), the internal temperature of the wood is evaporated until the free water in the wood evaporates (i.e., the water content of the wood becomes less than the fiber saturation point) at a boiling point of water at a boiling point of 150 캜 to 160 캜 at 5 atm It is kept constant by the latent heat.

This is the principle that when water is boiled at atmospheric pressure, the temperature of the water is kept constant at 100 ° C at which water begins to boil. Accordingly, the first heat treatment step (S130) is a section in which the internal temperature of the wood maintains the boiling point of water under the pressure of the superheated water vapor set.

After the primary drying-heat treatment step (S120), the temperature of the wood is raised again (secondary drying-heat treatment step (S130)) since the thermal energy used as the latent heat of vaporization is used to heat the wood since there is no free water in the wood. . That is, the first drying-heat treatment step (S120) and the second drying-heat treatment step (S130) can be determined depending on the presence or absence of free water, and the heat treatment temperature is changed accordingly.

That is, in the primary drying-heat treatment step (S120), the temperature of the wood is kept constant at the boiling point of water (superheated water vapor), free water in the raw material is removed and heat treatment of the wood proceeds . At this time, the free water means liquid water flowing freely between the cell walls. That is, water that does not interact with the solute.

The secondary drying-heat treatment step (S130) may proceed to the point where the internal temperature of the wood begins to rise again from the boiling point of water at the target pressure condition and the internal temperature of the wood approaches the maximum temperature.

At this time, the temperature of the water may be 140 to 260 캜, and the target pressure may be 4 to 400 atm.

Thus, the maximum temperature of the internal temperature of the wood may be 140 ° C to 260 ° C.

For example, the secondary drying-heat treatment step (S130) begins to rise again from the range of 150 ° C to 160 ° C, which is the boiling point of water at 5atm, when the target pressure is 5atm, It may proceed to the point of time when it approaches.

Specifically, the second drying-heat treatment step (S130) removes the free water in the wood, removes the coupling water in the wood, and starts to increase the temperature of the wood to the temperature above the boiling point of water at the target pressure condition. Up to a point in time when the internal temperature of the heat exchanger 1 approaches the maximum temperature.

In the secondary drying-heat treatment step (S130), there is no free water in the wood, and only the number of bonds is present. While this combined water is removed, the wood interior temperature rises above the boiling point of water at the target pressure condition and reaches the final target temperature (maximum temperature).

When the internal temperature of the wood reaches the final temperature (maximum temperature), the water content of the wood reaches the equilibrium moisture content and no further drying occurs. That is, only the heat treatment is performed, and this period becomes the concentrated heat treatment step (S140).

That is, in the first drying-heat treatment step (S120) and the second drying-heat treatment step (S130), drying and heat treatment are simultaneously performed, but only the heat treatment is performed in the concentrated heat treatment step (S140).

The concentrated heat treatment step (S140) may be determined as a period in which the internal temperature of the wood maintains the maximum temperature.

At this time, the maximum temperature of the internal temperature of the wood may be 140 캜 to 260 캜.

For example, in the concentrated heat treatment step (S140), when the target pressure is 5 atm, the internal temperature of the wood can be determined as a period of maintaining the maximum temperature of 220 캜.

Specifically, the concentrated heat treatment step (S140) can be determined from the time when the internal temperature of the wood starts to approach the maximum temperature to the time when the heater ends the operation.

Since the heat treated wood shows different degrees of heat treatment depending on the maximum temperature inside the wood during the heat treatment and the concentrated heat treatment time, the 'heat treatment degree', which is the index indicating the degree of heat treatment, is the highest temperature that the internal temperature of the wood reaches during the heat treatment, Time. ≪ / RTI >

The concentrated heat treatment step (S140) according to the embodiment of the present invention is a period from the time when the water content of the wood reaches the equilibrium moisture content to the end of the process, and the processing time is changed according to the end use of the dry- You can decide.

The processing time is the elapsed time from the point when the temperature inside the wood reaches the maximum temperature to the point at which the entire process ends, while monitoring the internal temperature of the wood in real time during the concentrated heat treatment step (S140).

Thus, the time at which the internal temperature of the wood maintains its maximum temperature should be determined by the end use of the dry-heat treated wood, which can be determined by monitoring the internal temperature change of the wood in real time.

Wood can be used for various purposes such as building furniture, interior and exterior materials, flooring, building materials, woodcarving, desks, chairs, bookshelves, household goods and the like.

For example, in the case of wood requiring high strength performance such as building materials, the processing time of the concentrated heat treatment step (S140) is reduced, and in the case of wood in which relative strength performance such as household goods is not important, The processing time of the heat treatment step S140 can be further increased.

In addition, if color soft wood is required, the processing time of the concentrated heat treatment step (S140) is reduced, and the processing time of the concentrated heat treatment step (S140) can be further increased if thick colored wood is required.

If the treatment time in the concentrated heat treatment step (S140) is short, the heat treatment effect is not sufficiently manifested, and if it is long, the heat treatment is excessively performed, and the strength is reduced.

The cooling step (S150) for cooling the concentrated heat-treated wood is performed.

The cooling step (S150) is a step of completing the dry-heat treatment of the raw material by cooling the internal temperature of the reactor, and the cooling step (S150) is a step of cooling the internal temperature of the reactor at a rate of -20 ° C / hour or less .

The cooling step (S150) can slowly cool the wood in the reactor where the process has ended.

Wood can be controlled for the occurrence of defects depending on the cooling rate. Since wood has a property of shrinking or expanding not only by moisture change but also by temperature change, it is necessary to slow down the occurrence of defects in order to suppress drying defects due to rapid temperature changes.

That is, when the wood is cooled at a low temperature or at a normal temperature, a large temperature gradient occurs between the surface and the inside of the wood to increase the possibility of occurrence of defects. However, if the wood is cooled slowly at a high temperature, It is possible to reduce the possibility of occurrence.

Since the raw material drying-heat treatment process according to the embodiment of the present invention is performed simultaneously with the drying and heat treatment of the raw materials, energy consumption, reheat energy consumption, and time can be saved as compared with the case where the drying and the heat treatment proceed to separate processes.

In addition, since the drying and heat treatment of the raw materials are performed at the same time, the balance moisture content of the wood is reduced, thereby improving the dimensional stability, improving the post-internal performance, Can be improved.

In addition, the raw material drying-heat treatment process according to the embodiment of the present invention enables the production of high-quality wood materials, and the productivity and work efficiency of the wood can be greatly improved by simultaneously performing the drying treatment and the heat treatment of the raw materials.

In addition, the raw material drying-heat treatment process according to the embodiment of the present invention can suppress the segregation by drying or heat treatment by drying-heat-treating the wood using superheated water vapor

In addition, in the raw material drying-heat treatment process according to the embodiment of the present invention, the wood material with desired color tone can be obtained by drying-heat-treating the wood using the superheated steam, and the rosin removal effect in the pine and larch can be obtained have.

FIG. 2 is a graph illustrating a process of drying and heating a raw material according to an embodiment of the present invention.

FIG. 2 shows a raw material drying-heat treatment process according to a preferred embodiment, but is not limited thereto.

Referring to FIG. 2, the temperature of the steam (blue line) and the pressure (green line) are measured from the initial temperature of 20 占 폚 and the initial pressure of vacuum (0 atm from the air in the reactor) And reaches the target temperature and target pressures of 260 캜 and 5 atm in about 4 hours, and is maintained until the process is terminated.

The internal temperature of the wood (brown line) increased relatively slowly to reach the boiling point of water at 5 atm after about 4 hours at 150 < 0 > C, and then a first drying-heat treatment step was carried out with a constant temperature for about 4 hours . The constant temperature of the wood is the section where the free water is evaporated in the form of liquid in the inside of the wood, and the temperature of the wood is maintained because heat energy is used for the latent heat of evaporation necessary for vaporization of liquid water vapor.

At the point when the temperature of the wood rises again, there is no free water in the wood and the fiber saturation point at which only the bonding number exists is reached. After the free water in the wood is removed, the temperature of the wood is raised to remove the bonding water in the wood, and the secondary drying-heat treatment proceeds at a high temperature.

When the temperature of the wood approaches the peak, the water content of the wood becomes the equilibrium moisture content, no further drying occurs, and a concentrated heat treatment step is carried out in which only the heat treatment is performed. The intensive heat treatment step was carried out for about 2 hours and the maximum temperature of the internal temperature of the wood was 220 ° C.

The intensively heat treated wood was slowly cooled at a rate of -20 ° C / hour inside the reactor.

Manufacturing example

[Comparative Example 1]

Larch larvae were cut, processed and stored in a cold storage warehouse at 4 ° C.

[Comparative Example 2]

The larch of [Comparative Example 1] was heat-dried for 60 hours at a temperature range of 80 to 100 캜.

[Comparative Example 3]

The heat-dried larch of Comparative Example 2 was gradually heated for 30 hours so that the internal temperature of the wood reached 190 占 폚 and then the high heat-treated wood of 190 占 폚 maintained for 2 hours was prepared.

[Comparative Example 4]

A high heat-treated wood at 210 占 폚 was prepared in the same manner as in [Example 3] except that the temperature was increased to 210 占 폚 in [Comparative Example 3].

[Example 1]

After cutting the larch (raw material), drying-heat treatment was carried out using superheated steam at a temperature of 260 캜 and a pressure of 5 atm in a reactor in which air was removed and a certain amount of water was introduced. Four hours after the start of the process, the wood reached a boiling point of 150 ° C at 5 atm, followed by a primary drying-heat treatment in which free water was removed in the raw material for about 4 hours and heat treated at a relatively low temperature. After the free water in the raw material was removed, the temperature of the wood rose again and the combined water was removed until it reached the maximum temperature, and the secondary drying-heat treatment proceeded at a temperature higher than the primary drying-heat treatment. After the internal temperature of the wood reached the maximum temperature, the intensive heat treatment proceeded for about 2 hours (the maximum temperature of the internal temperature of the wood was 220 ° C.) until the process was finished, and after the process was finished, Cooled.

3 is a cross-sectional view of a wood in a raw material state and a wood subjected to a raw material drying-heat treatment process according to Example 1 of the present invention.

Referring to FIG. 3, it can be seen that the wood subjected to the drying-heat-treating process according to the embodiment of the present invention is not split.

Hereinafter, characteristics of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention will be described with reference to FIG. 4 to FIG.

4 to 8 are Comparative Examples 1 and 2, Comparative Example 2 is a hot-air drying material, Comparative Example 3 is a 190 ° C heat treatment material, Comparative Example 4 is a 210 ° C heat treatment material, 5atm & 220 ℃ Superheated steam drying - It is heat treated material.

4 is a graph showing the equilibrium moisture content of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention.

4, the equilibrium moisture content of the raw material-dried and heat-treated wood according to Example 1 of the present invention was lower than that of Comparative Examples 1 to 4. That is, it can be seen that the dimensional stability of the raw material-heat-treated wood according to Example 1 of the present invention is improved by decreasing the equilibrium moisture content, and the post-internal performance is improved.

FIG. 5 is a graph showing the compressive strength parallel to the grain of the raw material wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention.

Referring to FIG. 5, the wood-based dry-heat treated wood according to Example 1 of the present invention had an improved overall compressive strength as compared with Comparative Examples 1 to 4.

FIG. 6 is a graph showing the mass loss rate and deterioration rate of the brown rot fungi of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention depression rate.

Referring to FIG. 6, the mass reduction rate of the brown rot fungus was decreased in the raw material-heat-treated wood according to Example 1 of the present invention, as compared with Comparative Examples 1 to 4, thereby increasing the suppression rate of rot.

FIG. 7 is a graph showing the mass loss rate and deterioration rate of white rot fungi of the wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention depression rate.

7, as compared with Comparative Examples 1 to 4, the mass reduction rate by the white rot fungus was decreased in the raw material-heat treated wood according to Example 1 of the present invention, thereby increasing the suppression rate of the rot fungus.

FIG. 8 is a graph showing the total volume shrinkage of wood subjected to the raw material drying-heat treatment process according to Comparative Examples 1 to 4 and Example 1 of the present invention.

Referring to FIG. 8, the total volume contraction ratio of the raw material-dried and heat-treated wood according to Example 1 of the present invention was lower than that of Comparative Examples 1 to 4. In particular, it can be seen that the total volume shrinkage (2%) of the raw material-dried and heat-treated raw wood according to Example 1 of the present invention is reduced by 8% p compared to the untreated Comparative Example 1 (10%).

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (9)

Preparing and heating the raw material;
A first drying-heat treatment step of performing heat treatment to remove free water in the raw material using superheated steam;
A secondary drying-heat treatment step of removing the coupling water in the wood by using the superheated water vapor and performing a heat treatment at a higher temperature than the primary drying-heat treatment step;
A concentrated heat treatment step of performing heat treatment at a maximum temperature of the internal temperature of the secondary drying-heat-treated wood which has reached equilibrium moisture content using the superheated water vapor; And
A cooling step for cooling the concentrated heat-treated wood
Lt; / RTI >
In the first drying-heat treatment step, the second drying-heat treatment step and the concentrated heat treatment step, drying and heat treatment are performed in the same apparatus,
Wherein the primary drying-heat treating step, the secondary drying-heat treating step and the concentrated heat treating step are carried out at a superheated steam temperature of 140 ° C to 260 ° C and superheated steam pressure of 4atm to 400atm,
Wherein the degree of heat treatment of the dry-heat treated wood is determined by multiplying the maximum temperature inside the wood during the concentrated heat treatment and the concentrated heat treatment time.
The method according to claim 1,
Wherein the primary drying-heat treatment step, the secondary drying-heat treatment step, and the concentrated heat treatment step are carried out at a superheated water vapor temperature of 260 ° C and a superheated water vapor pressure of 5atm.
The method according to claim 1,
The step of preparing and heating the raw material includes:
Wherein the raw material internal temperature is maintained until the boiling point of the water reaches the target pressure condition.
The method according to claim 1,
Wherein the primary drying-heat treating step comprises:
Wherein the internal temperature of the wood is a zone where the boiling point of water is maintained under the target pressure condition.
The method according to claim 1,
Wherein the secondary drying-heat treatment step comprises:
Wherein the internal temperature of the wood starts to rise again from the boiling point of water at the target pressure condition and progresses to the point where the internal temperature of the wood approaches the maximum temperature.
The method according to claim 1,
Wherein the concentration heat treatment step comprises:
A section where the internal temperature of the wood maintains the maximum temperature
A raw material drying-heat treatment step
The method according to claim 1,
Wherein the concentration heat treatment step comprises:
The treatment time is determined according to the use of the dry-heat treated wood,
The processing time is determined as an elapsed time from a time point at which the internal temperature of the wood is close to the maximum temperature to a point at which the centralized heat treatment step ends, while the internal temperature of the wood is monitored in real time during the centralized heat treatment step A raw material drying-heat treatment process.
The method according to claim 1,
Wherein the first drying-heat-treating step and the second drying-heat-treating step are carried out in a closed reactor.
The method according to claim 1,
Wherein the cooling step is carried out by slowly cooling the raw material at a rate of -20 DEG C / hour or less in the reactor in which the process is completed.

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