JP2871525B2 - Dehydration and drying method of wood using carbon dioxide gas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a can effectively dewatering the free water contained in the wood without using rather, yet heating device to cause surface cracks on wood carbonate
The present invention relates to a method for dehydrating and drying wood using gas .

[0002]

2. Description of the Related Art Wood is a resource that is regenerated year by year, and the stock of planted forests planted after the war is increasing, but low-quality timber and thinned timber are not always fully utilized. The fact is that 60% relies on imports from overseas.
As a result, many issues such as global environmental destruction, national land preservation, and water resources cultivation have been raised, and the development of effective utilization technology is desired.

Conventionally, as a method of drying wood or improving the permeability of a chemical solution, first, a chemical solution such as an organic solvent is used as a chemical treatment means to extract a substance deposited in a hole in a wall, There is an attempt to disassemble the hole.

[0004] Secondly, there is a means for utilizing the permeability from the cut edge by mechanically creating a puncture on the material surface by a needle, laser light or high-pressure injection of liquid or the like. Thirdly, there is an attempt to use steaming treatment, which is well-known as a pretreatment for wood drying, to improve permeability, and is generally known as a physical treatment method such as steaming, steam treatment, low-pressure steam explosion treatment, and heat treatment. I have. In each of these methods, the basic principle is that wood is heated by pressurized steam to soften and destroy the wall holes.

[0005] The core and sapwood of the cedar wood will now be described. In the cross section of the cedar wood 16 shown in Fig. 3, A is the sapwood and B is the core. When the stem of the cedar wood 16 is cut toward the center of the tree, there are shades of color to distinguish between the edge and the center of the wood at the edge of the wood. Material B is dark.

Generally, as shown in FIG. 4, the trunk of a tree is composed of a bark 21, a cambium 22, a sapwood A, a core B, and a pith 23, and water 24 and nutrients 25 sucked from the roots are sapwood A.
As a result, photosynthesis occurs by receiving carbon dioxide 26 and light 27 from the outside, and the solution of the photosynthetic substance descends through the phloem of the bark 21 and is distributed to each part and grows. At the time of the young tree, everything is sapwood A. When the tree grows to a certain size, a conical core B is formed at the center of the trunk from the lower part to the upper part, and the sapwood A surrounds the core. It becomes a wrapping shape.

Normally, the diameter of the core material B increases as the diameter of the stem increases, but the ratio of the core material B is low during active periods of hypertrophy.
In old-aged large-diameter trees, the width of the sapwood A is narrow. Sapwood A
In the area of, there is conduction of moisture and storage of nutrients,
In the large-diameter tree, the living cells in the portion of the core material B disappear, and the parenchyma cells that have been storing nutrients also stop their activities.

[0008]

Among the above-mentioned various methods known as a conventional method for drying wood or a method for improving chemical liquid permeability, a chemical liquid such as an organic solvent is used as a first chemical treatment means. The method of extracting substances deposited in the wall hole and decomposing the wall hole has disadvantages in operation, such as the expensive organic solvent used and long processing time. There is a problem that it takes extra.

In the second method, a method of mechanically creating a puncture on a material surface with a needle, a laser or a high-pressure liquid jet, the processing time is short, but the processing apparatus is large, and the appearance of the obtained wood is poor. Or the strength is reduced. Further, the physical means using the third steaming treatment is a method in which wood is heated by pressurized steam to soften and destroy wall holes. In the wood-related industry, a permanent boiler can be used and a chemical solution after drying is used. Although there is an advantage that the autoclave can be shared by injection etc., there is a possibility that the steaming and steam treatment may cause a change in the color of the wood or a decrease in the strength, and the heat treatment in the low pressure steam explosion treatment is effective at the part close to the tree core However, there is a problem that the apparatus becomes large-scale and cannot be recognized.

[0010] Usually, the factor that governs the drying property and chemical permeability of wood is the wall hole in each cell tissue, and in conifers, the bounded wall hole is the passage. In the sapwood A part, the holes are open, so that the passages are for water or nutrients. However, in the core material B, these holes are closed, so that it is difficult to permeate or permeate a liquid or gas. Generally, this is referred to as closing of the wall hole. However, due to the closing of the wall hole, the above-described problem that the core material B is dried slowly and the injectability of the chemical solution is poor.

In particular, conventionally, conifers are said to be poor in both dryness and impregnation with chemicals, and poor dryness leads to an increase in the weight of wood after logging, resulting in overloading during transportation by vehicle. Spots may occur.

Therefore, the present invention solves the problems of the conventional method for drying wood, and effectively removes free water contained in the wood without causing surface cracks in the wood. Wood using carbon dioxide that can be dehydrated
It is an object of the present invention to provide a dehydration / drying method .

[0013]

According to the present invention, in order to achieve the above object, wood and high-pressure carbon dioxide gas are sealed in a sealed pressure-resistant container, and after holding for a certain period of time, the sealed pressure-resistant container is opened. Dehydration of wood using carbon dioxide, which forcibly dehydrates the free water contained in it with carbon dioxide
Provides water and drying methods .

Furthermore, <br/> by to hold a certain time by pressing the high-pressure carbon dioxide in the wood that is enclosed in the closed pressure vessel is, carbon dioxide gas was once dissolved in water in the timber, then The free water contained in the wood is forcibly dehydrated by releasing the carbon dioxide gas dissolved in the water in the wood by releasing the pressure to the outside of the wood with the moisture.
A method for dehydrating and drying wood using carbon dioxide gas is provided.

[0015]

[Function] Dehydration and drying of wood using carbon dioxide gas of the above configuration
According to the drying method , carbon dioxide gas is injected into wood sealed in a sealed pressure-resistant container , so that the injected carbon dioxide gas dissolves in moisture in the wood, and the temperature, volume, and pressure in the sealed pressure-resistant container depend on the temperature, volume, and pressure. To produce a saturated solution with the moisture in the wood. After a certain time, when the high pressure state of the sealed pressure-resistant container is released , the sealed pressure-resistant container is released.
Since the pressure in the pressure vessel decreases, the carbon dioxide dissolved in the water in the wood is released while pushing out the water in the wood from the inside of the wood to the outside. By repeating this operation a predetermined number of times according to the dimensions of the wood, the moisture in the wood is gradually released, and drying is promoted. In addition, since these treatments can be easily performed at the logging site in the mountains if there is only a sealed pressure-resistant container, the weight of wood shipped from the site can be reduced. The problem is solved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, in order to prevent surface cracking in a drying process, carbon dioxide gas is once dissolved in water in wood by press-injecting carbon dioxide gas into wood at a high pressure without using a heating device. Ri by that then pressed open, the open pressure time volume
Dehydration and drying of the wood is performed by increasing the amount of expansion to release carbon dioxide dissolved in the water in the wood to the outside of the wood with the water .

Hereinafter, the carbon dioxide gas according to the present invention is used.
A description will be given based on specific examples of a method of dehydrating and drying wood . Figure 1 is a overview diagram for carrying out the present invention, 1 in the figure is an autoclave as a closed pressure vessel 2 jig for not to contact the timber with the inner wall of the autoclave 1,
Reference numeral 3 denotes a wood test material for processing purposes, 4 denotes an upper cover of the autoclave 1, 5 denotes a common valve for pressurizing and depressurizing high-pressure carbon dioxide gas , and 6 denotes a pressure sensor for detecting the internal pressure of the autoclave 1.

Example 1 As raw wood, cedar wood from Reihoku, Kochi Prefecture was cut into sapwood and heartwood immediately after cutting, and the fiber direction was 1
The material 3 was taken as a test material 3 after logging in a 00 mm, 30 mm in the radial direction, and 30 mm in the tangential direction and storing it in water. These test materials 3 were taken out of the water immediately before the treatment, and after removing water adhering to the surface, the weight was measured, and the test materials 3 were placed in the autoclave 1 so as not to come into contact with the inside of the autoclave 1 and sealed. Immediately afterwards, the pressurized / depressurized shared valve 5
Then, carbon dioxide was sealed at a pressure of 5 kgf / cm ² according to the instructions of a pressure gauge installed in the autoclave 1. Part 3
After 0 minute, the carbon dioxide gas is released at once from the pressurized / depressurized shared valve 5, and when the indication of the pressure gauge becomes equal to the atmospheric pressure, the test material 3 is taken out of the autoclave 1 and water adhering to the surface is removed. The weight was measured.

[Example 2] As raw wood, cedar wood from Reihoku, Kochi Prefecture is divided into sapwood and heartwood immediately after cutting, and fiber direction 1
The material 3 was taken as a test material 3 after logging in a 00 mm, 30 mm in the radial direction, and 30 mm in the tangential direction and storing it in water. These test materials 3 were taken out of the water immediately before the treatment, and after removing water adhering to the surface, the weight was measured, and the test materials 3 were placed in the autoclave 1 so as not to come into contact with the inside of the autoclave 1 and sealed. Immediately afterwards, the pressurized / depressurized shared valve 5
Then, carbon dioxide was sealed at a pressure of 10 kgf / cm ² according to the instructions of a pressure gauge installed in the autoclave 1. Thirty minutes later, carbon dioxide gas is released at once from the pressurized / depressurized shared valve 5, and when the indication of the pressure gauge becomes equal to the atmospheric pressure, the test material 3 is taken out of the autoclave 1 and water adhering to the surface is removed. And the weight was measured.

Example 3 As raw wood, cedar wood from Reihoku, Kochi Prefecture was cut into sapwood and heartwood immediately after cutting, and the fiber direction was 1
The material 3 was taken as a test material 3 after logging in a 00 mm, 30 mm in the radial direction, and 30 mm in the tangential direction and storing it in water. These test materials 3 were taken out of the water immediately before the treatment, and after removing water adhering to the surface, the weight was measured, and the test materials 3 were placed in the autoclave 1 so as not to come into contact with the inside of the autoclave 1 and sealed. Immediately afterwards, the pressurized / depressurized shared valve 5
Then, carbon dioxide was sealed at a pressure of 15 kgf / cm ² according to the instructions of a pressure gauge installed in the autoclave 1. Thirty minutes later, carbon dioxide gas is released at once from the pressurized / depressurized shared valve 5, and when the indication of the pressure gauge becomes equal to the atmospheric pressure, the test material 3 is taken out of the autoclave 1 and water adhering to the surface is removed. And the weight was measured.

[Example 4] As raw wood, cedar wood from Reihoku, Kochi prefecture is divided into sapwood and heartwood immediately after cutting, and the fiber direction is 1
The material 3 was taken as a test material 3 after logging in a 00 mm, 30 mm in the radial direction, and 30 mm in the tangential direction and storing it in water. These test materials 3 were taken out of the water immediately before the treatment, and after removing water adhering to the surface, the weight was measured, and the test materials 3 were placed in the autoclave 1 so as not to come into contact with the inside of the autoclave 1 and sealed. Immediately afterwards, the pressurized / depressurized shared valve 5
Then, carbon dioxide was sealed at a pressure of 10 kgf / cm ² according to the instructions of a pressure gauge installed in the autoclave 1. Thirty minutes later, the carbon dioxide gas is released at once from the pressurized / depressurized shared valve 5, and when the indication of the pressure gauge becomes equal to the atmospheric pressure, the operation of terminating the release is performed five times.
From the sample material, remove water adhering to the surface,
The weight was measured.

Example 5 As raw wood, cedar wood from Reihoku, Kochi Prefecture was cut into sapwood and heartwood immediately after cutting, and the fiber direction was 1
The material 3 was taken as a test material 3 after logging in a 00 mm, 30 mm in the radial direction, and 30 mm in the tangential direction and storing it in water. These test materials 3 were taken out of the water immediately before the treatment, and after removing water adhering to the surface, the weight was measured, and the test materials 3 were placed in the autoclave 1 so as not to come into contact with the inside of the autoclave 1 and sealed. Immediately afterwards, the pressurized / depressurized shared valve 5
Then, carbon dioxide was sealed at a pressure of 10 kgf / cm ² according to the instructions of a pressure gauge installed in the autoclave 1. Thirty minutes later, the carbon dioxide gas is released at once from the pressurized / depressurized shared valve 5, and when the pressure gauge indication becomes equal to the atmospheric pressure, the operation of terminating the release is performed 10 times. The test material 3 was taken out, water adhering to the surface was removed, and the weight was measured.

Comparative Example 1 As raw wood, cedar wood from Reihoku, Kochi Prefecture was cut into sapwood and heartwood immediately after cutting.
The material 3 was taken as a test material 3 after logging in a 00 mm, 30 mm in the radial direction, and 30 mm in the tangential direction and storing it in water. These test materials 3 were taken out of the water immediately before the treatment, and after removing water adhering to the surface, the weight was measured, and the test materials 3 were placed in the autoclave 1 so as not to come into contact with the inside of the autoclave 1 and sealed. Immediately afterwards, the pressurized / depressurized shared valve 5
Then, nitrogen gas was sealed at a pressure of 10 kgf / cm ² according to the instructions of a pressure gauge installed in the autoclave 1. Thirty minutes later, the nitrogen gas is released from the pressurized / depressurized shared valve 5 at a stroke, and when the indication of the pressure gauge becomes equal to the atmospheric pressure, the test material 3 is taken out of the autoclave 1 to remove water adhering to the surface. And the weight was measured.

Comparative Example 2 As raw wood, cedar wood from Reihoku, Kochi Prefecture was divided into sapwood and heartwood immediately after cutting, and the fiber direction was 1
The material 3 was taken as a test material 3 after logging in a 00 mm, 30 mm in the radial direction, and 30 mm in the tangential direction and storing it in water. These test materials 3 were taken out of the water immediately before the treatment, and after removing water adhering to the surface, the weight was measured, and the test materials 3 were placed in the autoclave 1 so as not to come into contact with the inside of the autoclave 1 and sealed. Immediately afterwards, the pressurized / depressurized shared valve 5
Then, nitrogen gas was sealed at a pressure of 10 kgf / cm ² according to the instructions of a pressure gauge installed in the autoclave 1. Thirty minutes later, nitrogen gas was released at once from the pressurized / depressurized shared valve 5, and the operation of terminating the release was performed five times when the indication of the pressure gauge became equal to the atmospheric pressure.
From the sample material, remove water adhering to the surface,
The weight was measured.

The dried wood obtained in the above Examples 1 to 5 and Comparative Examples 1 and 2 is dried in a dryer at 110 ° C. to a completely dry state, and the water content before and after the treatment is determined from the absolute dry weight. The percentage was calculated, and the moisture content after the treatment when the moisture content before the treatment was set to 1 is shown in FIG.

As shown in FIG. 2, it was confirmed that the gas species used for drying wood was carbon dioxide gas superior to nitrogen gas, and that the number of treatments had a greater effect on the drying effect than the treatment pressure. .

[0027]

As described [Effect Invention above in detail, according to the dehydration and drying method of the wood using a carbon dioxide gas according to the present invention it was forcibly dissolved at high pressure moisture in the wood carbonate
Since the gas is forcibly dehydrated as the volume expansion at the time of opening pressure increases, the initial moisture content of the wood can be significantly reduced. Also, appearance as a method for drying treatment of wood, Ri by the fact that using a high pressure of carbon dioxide gas in place of the method using a conventional heat source, thereby preventing drying cracks of wood
It is possible to maintain high strength and effectively
Dehydration and drying can be performed .

Further, by performing the above-described processing at the time of logging in the mountains, the weight of dewatering of free water in the temporary pipe is reduced, and the problem of overloading during transportation by vehicle can be dealt with. Further, the drying time of the wood is shortened, and the drying cost is reduced.

[Brief description of the drawings]

FIG. 1 shows dehydration of wood using carbon dioxide gas according to the present invention.
· Outline diagram showing a drying process.

FIG. 2 is a graph showing changes in the water content of Examples of the present invention and Comparative Examples.

FIG. 3 is a cross-sectional view of a cedar material as an example of wood.

FIG. 4 is a schematic diagram showing the trunk structure of a tree and the process of growth.

──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Kensuke Yamazaki 3992 Fushida, Kochi City, Kochi Prefecture Kochi Prefectural Industrial Technology Center (56) References JP-A-59-101311 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) B27K 5/00

Claims (2)

(57) [Claims] 1. A sealed pressure-resistant container is filled with wood and high-pressure carbon dioxide gas, and after holding for a certain period of time, the sealed pressure-resistant container is opened to convert free water contained in the wood into carbon dioxide gas . <br/> Both use carbon dioxide, which is characterized by forced dehydration.
Dehydration and drying method of used wood . Wherein Ri by a carbon dioxide gas to a predetermined time held pressed at high pressure in sealed in a sealed pressure vessel timber,
The carbon dioxide gas was once dissolved in water in the timber, then the carbon dioxide dissolved in the water in the timber by pressure open to release with a water to wood outside, the free water contained in the wood Characterized by forced dehydration
A method for dehydrating and drying wood using carbon dioxide .