CN117584234A - Heat treatment process of wood and wood - Google Patents
Heat treatment process of wood and wood Download PDFInfo
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- CN117584234A CN117584234A CN202311831496.2A CN202311831496A CN117584234A CN 117584234 A CN117584234 A CN 117584234A CN 202311831496 A CN202311831496 A CN 202311831496A CN 117584234 A CN117584234 A CN 117584234A
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- 239000002023 wood Substances 0.000 title claims abstract description 134
- 238000010438 heat treatment Methods 0.000 title claims abstract description 129
- 238000000034 method Methods 0.000 title claims abstract description 38
- 230000008569 process Effects 0.000 title claims abstract description 32
- 238000003763 carbonization Methods 0.000 claims abstract description 145
- 238000001816 cooling Methods 0.000 claims abstract description 36
- 238000010025 steaming Methods 0.000 claims description 49
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 238000007789 sealing Methods 0.000 claims description 2
- 230000000630 rising effect Effects 0.000 claims 6
- 238000010792 warming Methods 0.000 claims 1
- 238000005336 cracking Methods 0.000 abstract description 14
- 230000009286 beneficial effect Effects 0.000 abstract description 4
- 230000001105 regulatory effect Effects 0.000 abstract description 2
- 238000005507 spraying Methods 0.000 description 37
- 230000001276 controlling effect Effects 0.000 description 10
- 230000008859 change Effects 0.000 description 9
- 238000010000 carbonizing Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 5
- 240000002871 Tectona grandis Species 0.000 description 4
- 238000007605 air drying Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000010875 treated wood Substances 0.000 description 3
- 244000166124 Eucalyptus globulus Species 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000002522 swelling effect Effects 0.000 description 2
- 229920002522 Wood fibre Polymers 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000007676 flexural strength test Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 230000007363 regulatory process Effects 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002025 wood fiber Substances 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27M—WORKING OF WOOD NOT PROVIDED FOR IN SUBCLASSES B27B - B27L; MANUFACTURE OF SPECIFIC WOODEN ARTICLES
- B27M1/00—Working of wood not provided for in subclasses B27B - B27L, e.g. by stretching
- B27M1/08—Working of wood not provided for in subclasses B27B - B27L, e.g. by stretching by multi-step processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
- B27K5/0085—Thermal treatments, i.e. involving chemical modification of wood at temperatures well over 100°C
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27M—WORKING OF WOOD NOT PROVIDED FOR IN SUBCLASSES B27B - B27L; MANUFACTURE OF SPECIFIC WOODEN ARTICLES
- B27M1/00—Working of wood not provided for in subclasses B27B - B27L, e.g. by stretching
- B27M1/06—Working of wood not provided for in subclasses B27B - B27L, e.g. by stretching by burning or charring, e.g. cutting with hot wire
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical And Physical Treatments For Wood And The Like (AREA)
Abstract
The invention relates to the technical field of wood processing, and discloses a wood heat treatment process and a wood, which comprise the steps of heating a carbonization kiln to 165-170 ℃ by adopting three-stage heating, keeping the temperature for 4-4.5 h for carrying out micro-carbonization treatment on the wood, cooling the wood after the micro-carbonization treatment, regulating the humidity of the carbonization kiln, and finally reducing the temperature of the wood to room temperature by adopting a natural cooling mode. The gradual heating mode can effectively reduce cracking and deformation caused by heating of the wood at a higher speed, is beneficial to balancing the internal and external temperatures of the wood, and prevents uneven internal and external changes caused by overlarge temperature difference. The content of hydrophilic factors in the wood is reduced through carbonization treatment within a set temperature and time, the hygroscopicity of the wood is reduced, the stress in the wood is released, and the phenomena of wood cracking or tearing are improved. The structure of the wood is stabilized in a gradual cooling mode, so that cracking is further reduced.
Description
Technical Field
The invention relates to the technical field of wood processing, in particular to a heat treatment process of wood and the wood.
Background
When the external damp-heat condition of the wood changes, the wood is easy to shrink, wet and expand, is a material with unstable size, the cut wood has larger water content and higher internal stress, and if the cut wood is directly processed into a plate or other products, the products are easy to sink or crack after the water in the plate is evaporated, or the products are easy to absorb water and swell, so that the products have defects, and the quality of the products is affected.
It can be seen that there is a need for improvements and improvements in the art.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide a heat treatment process for wood and the wood, which aims to reduce hygroscopicity and internal stress of the wood and avoid phenomena of cracking or tearing of the wood when the wood is placed for a long time.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a process for heat treatment of wood, comprising the steps of:
s1, heating and raising the temperature: placing the wood stacked on the frame body into a carbonization kiln, and heating the carbonization kiln at room temperature once until the temperature is 60-70 ℃ and the heating speed is 5-10 ℃/h; carrying out secondary heating on the carbonization kiln until the temperature is 125-135 ℃ and the heating speed is 5-10 ℃/h; heating the carbonization kiln for three times until the temperature is 165-170 ℃ and the heating speed is 5-10 ℃/h;
s2, carbonization treatment: maintaining the temperature in the carbonization kiln at 165-170 ℃ for 4-4.5 h;
s3, cooling and humidifying: stopping heating the carbonization kiln, and steaming the carbonization kiln when the temperature of the carbonization kiln is above 100 ℃; when the temperature of the carbonization kiln is below 100 ℃, adding cold water to regulate humidity and cool, and stopping the machine for kiln sealing;
s4, cooling balance: and (5) when the temperature in the carbonization kiln is reduced to below 60 ℃, taking the wood out of the kiln and cooling to room temperature.
In the heat treatment process of the wood, in the heating and temperature raising process, the carbonization kiln is required to be steamed every 60min, the steaming time is 0.5-1.0 min, and the humidity in the carbonization kiln is controlled to be 80-95%.
The heat treatment process of the wood comprises the steps of heating the wood for 0.5min by spraying, heating the wood for 0.7min by spraying, and heating the wood for three times for 1.0min.
In the heat treatment process of the wood, in the carbonization treatment process, the carbonization kiln is required to be steamed every 60min, the steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-95%.
In the heat treatment process of the wood, in the cooling and humidity regulating process, every 45min needs to be sprayed and steamed to a carbonization kiln, the spraying and steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-95%.
The target temperature of primary heating is 65 ℃, the target temperature of secondary heating is 130 ℃, and the target temperature of tertiary heating is 170 ℃.
The heat treatment process of the wood comprises the steps of heating at a primary heating rate of 8 ℃/h, heating at a secondary heating rate of 5 ℃/h and heating at a tertiary heating rate of 6 ℃/h.
The heat treatment process of the wood comprises the step of naturally airing the wood in advance until the water content is 26-32% before the wood enters a carbonization kiln.
A wood is prepared by the heat treatment process of the wood.
The beneficial effects are that:
the invention provides a heat treatment process for wood and the wood, which can effectively reduce cracking and deformation caused by heating the wood at a higher speed by adopting a three-stage gradual heating method, protect the integrity of raw materials, facilitate the balance of the internal and external temperatures of the wood, gradually release the internal stress of the wood, prevent the uneven change of the internal and external caused by overlarge temperature difference, better control the reaction process and facilitate the production of carbonized wood with higher quality. The temperature and time of carbonization treatment are controlled, so that the content of hydrophilic factors in the wood can be reduced, the hygroscopicity of the wood is reduced, the stress in the wood is released, the phenomena of wood cracking or tearing are improved, the structure of the wood is stabilized, the biological durability is improved, and the mechanical properties such as the hardness, the strength and the elastic modulus of the wood can be properly increased. The two-stage cooling mode is adopted, so that the performance of the wood is stabilized, the wood is prevented from cracking due to the change of internal stress caused by the rapid change of the ambient temperature, and the production efficiency is improved. And then the wood in a relatively stable state is cooled to room temperature by adopting a natural cooling mode, so that the heat treatment efficiency is further improved.
Drawings
Fig. 1 is a flow chart of a heat treatment process of wood provided by the invention.
Fig. 2 is a schematic view of wood before entering a carbonization kiln.
Fig. 3 is a schematic view of wood in a carbonized state.
Fig. 4 is a schematic view of wood before and after heat treatment, wherein the left view is wood before heat treatment and the right view is wood after heat treatment.
Detailed Description
The invention provides a wood heat treatment process and wood, which are used for making the purposes, technical schemes and effects of the invention clearer and more definite, and the invention is further described in detail below by referring to the attached drawings and examples. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1-3, the present invention provides a heat treatment process for wood, comprising the following steps:
(1) Heating and heating: wood stacked on a frame body (before entering a carbonization kiln, the wood is naturally dried in advance until the water content is 26-32%, the saturation point range of wood fiber is 26-32% according to different tree species, the heat treatment period can be shortened, and the energy consumption can be reduced) is put into the carbonization kiln, the frame body is conveyed into the carbonization kiln by adopting a conveying platform, the carbonization kiln at room temperature is heated once until the temperature is 60-70 ℃, the heating speed is 5-10 ℃/h, the carbonization kiln needs to be steamed at intervals of 60 minutes, the steaming time is 0.5-1.0 min, and the humidity in the carbonization kiln is controlled to be 80-95%. And (3) carrying out secondary heating on the carbonization kiln until the temperature is 125-135 ℃, wherein the heating speed is 5-10 ℃/h, spraying and steaming are carried out on the carbonization kiln every 60min, the spraying and steaming time is 0.5-1.0 min, and the humidity in the carbonization kiln is controlled to be 80-95%. Heating the carbonization kiln for three times until the temperature is 165-170 ℃, the heating speed is 5-10 ℃/h, the carbonization kiln is required to be steamed every 60min, the steaming time is 0.5-1.0 min, and the humidity in the carbonization kiln is controlled to be 80-95%.
The three-section gradual heating mode is adopted to reach carbonization temperature, so that cracking and deformation caused by heating of wood at a high speed can be effectively reduced, the integrity of raw materials is protected, the balance of the internal and external temperatures of the wood is facilitated, the internal stress of the wood is gradually released, the uneven change of the internal and external caused by overlarge temperature difference is prevented, the reaction process can be better controlled, and the production of carbonized wood with higher quality is facilitated. Through intermittently spout steaming to the carbide kiln in, humidity in the carbide kiln is controlled, can prevent that timber surface from dewatering too fast in order to ensure that timber drying process is more even, when the temperature in the carbide kiln risees, if when the dehydration rate difference of timber surface and inside is too big, probably can lead to timber to crack or warp, through spouting steaming and controlling the humidity in the kiln, can slow down the difference of timber surface and inside dehydration rate, prevent timber to crack or warp, in addition the humidity of control each stage helps guaranteeing that the processing timber in the kiln keeps suitable state in whole intensification process, be favorable to quality and the specification of final product to reach the production requirement.
(2) Carbonizing: maintaining the temperature in the carbonization kiln at 165-170 ℃ for 4-4.5 h, spraying and steaming the carbonization kiln every 60min, wherein the spraying and steaming time is 1.0min, and controlling the humidity in the carbonization kiln to be 80-95%. Heating to the temperature and carbonizing the wood in the time range, wherein the carbonizing in the temperature range and the time range can reduce the content of hydrophilic factors in the wood, reduce the hygroscopicity of the wood, release the stress in the wood, improve the phenomena of wood cracking or tearing, stabilize the structure of the wood, improve the biological durability, increase the corrosion resistance and durability of the wood, enable the wood to be suitable for manufacturing furniture products, volatilize substances in the wood in the temperature range, increase the density of the wood, properly increase the mechanical properties such as the hardness, the strength and the elastic modulus of the wood, improve the fireproof performance of the wood to a certain extent through carbonizing at the temperature, and the carbonized wood has uniform high-grade natural color (see figure 4), thereby being a green and environment-friendly wood modification method.
(3) Cooling and humidifying: stopping heating the carbonization kiln, and when the temperature of the carbonization kiln is above 100 ℃, spraying and steaming the carbonization kiln every 45min, wherein the spraying and steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-95%. When the temperature of the carbonization kiln is below 100 ℃, adding cold water into the water tank for humidifying and cooling, and stopping the machine for 24 hours after the fan operates for three hours. The carbonization treatment can cause physical and chemical changes in the wood, residual moisture in the wood is evaporated at high temperature, and the intermittent steam spraying mode is adopted to cool and regulate humidity when the temperature in the kiln is above 100 ℃ in a cooling stage, so that the cooling mode of steam spraying is consistent with the mode of regulating the humidity in the kiln through steam spraying when the heating temperature is raised, the stability of the wood is influenced due to rapid change of the environment in the kiln, and the cracking probability of the wood is greatly reduced. And then the relatively stable wood is subjected to cold water humidifying, and is cooled in a shutdown kiln closing mode, so that the cooling rate of the wood can be accelerated, and the production efficiency of the wood heat treatment is improved. By adopting the two-stage cooling mode, the performance of the wood is stabilized, the wood is prevented from cracking due to the change of internal stress caused by the rapid change of the ambient temperature, and the production efficiency is improved.
(4) Cooling balance: and (5) when the temperature in the carbonization kiln is reduced to below 60 ℃, taking the wood out of the kiln and cooling to room temperature. The wood at the temperature has lower water content, complete release of internal stress and stable state, and can be discharged from the kiln and cooled to room temperature by natural cooling.
To further illustrate a wood heat treatment process and wood provided by the present invention, the following examples are provided.
Example 1
(1) Heating and heating: and (3) placing eucalyptus wood stacked on the frame body into a carbonization kiln, conveying the frame body into the carbonization kiln by adopting a conveying platform, heating the carbonization kiln at room temperature for one time until the temperature is 60 ℃, wherein the heating speed is 10 ℃/h, spraying and steaming the carbonization kiln at intervals of 60min for 0.7min, and controlling the humidity in the carbonization kiln to be 80-85%. And (3) carrying out secondary heating on the carbonization kiln until the temperature is 125 ℃, wherein the heating speed is 8 ℃/h, spraying and steaming are carried out on the carbonization kiln every 60min, the spraying and steaming time is 0.5min, and the humidity in the carbonization kiln is controlled to be 85-90%. Heating the carbonization kiln for three times until the temperature is 165 ℃, the heating speed is 5 ℃/h, spraying and steaming the carbonization kiln every 60min, the spraying and steaming time is 0.8min, and the humidity in the carbonization kiln is controlled to be 80-85%.
(2) Carbonizing: maintaining the temperature in the carbonization kiln at 165 ℃ for 4.5 hours, spraying and steaming the carbonization kiln at intervals of 60 minutes for 1.0min, and controlling the humidity in the carbonization kiln to be 80-85%.
(3) Cooling and humidifying: stopping heating the carbonization kiln, and when the temperature of the carbonization kiln is above 100 ℃, spraying and steaming the carbonization kiln every 45min, wherein the spraying and steaming time is 1.0min, and controlling the humidity in the carbonization kiln to be 80-85%.
(4) Cooling balance: and (5) when the temperature in the carbonization kiln is reduced to below 60 ℃, taking eucalyptus out of the kiln and cooling to room temperature.
Example 2
(1) Heating and heating: the teak stacked on the frame body is placed into a carbonization kiln, the frame body is sent into the carbonization kiln by adopting a conveying platform, the temperature of the carbonization kiln at room temperature is raised once until the temperature is 65 ℃, the temperature raising speed is 8 ℃/h, the carbonization kiln is required to be steamed at intervals of 60 minutes, the steaming time is 0.5min, and the humidity in the carbonization kiln is controlled to be 80-85%. And (3) carrying out secondary heating on the carbonization kiln until the temperature is 130 ℃, wherein the heating speed is 5 ℃/h, spraying and steaming are carried out on the carbonization kiln every 60min, the spraying and steaming time is 0.7min, and the humidity in the carbonization kiln is controlled to be 85-90%. Heating the carbonization kiln for three times until the temperature is 170 ℃, the heating speed is 6 ℃/h, the carbonization kiln needs to be steamed every 60min, the steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-85%.
(2) Carbonizing: maintaining the temperature in the carbonization kiln at 170 ℃ for 4 hours, spraying and steaming the carbonization kiln every 60 minutes, wherein the spraying and steaming time is 1.0min, and controlling the humidity in the carbonization kiln to be 83-88%.
(3) Cooling and humidifying: stopping heating the carbonization kiln, and when the temperature of the carbonization kiln is above 100 ℃, spraying and steaming the carbonization kiln every 45min, wherein the spraying and steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 83-88%.
(4) Cooling balance: and (5) cooling teak to room temperature after the temperature in the carbonization kiln is reduced to below 60 ℃.
Example 3
(1) Heating and heating: oak stacked on the frame body is placed into a carbonization kiln, the frame body is sent into the carbonization kiln by adopting a conveying platform, the temperature of the carbonization kiln at room temperature is raised once until the temperature is 65 ℃, the temperature raising speed is 5 ℃/h, the carbonization kiln is required to be steamed at intervals of 60 minutes, the steaming time is 0.7min, and the humidity in the carbonization kiln is controlled to be 80-85%. And (3) carrying out secondary heating on the carbonization kiln until the temperature is 135 ℃, wherein the heating speed is 7 ℃/h, spraying and steaming are carried out on the carbonization kiln every 60min, the spraying and steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 85-90%. Heating the carbonization kiln for three times until the temperature is 165 ℃, the heating speed is 10 ℃/h, the carbonization kiln needs to be steamed every 60min, the steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-85%.
(2) Carbonizing: maintaining the temperature in the carbonization kiln at 165 ℃ for 4.5 hours, spraying and steaming the carbonization kiln at intervals of 60 minutes for 1.0min, and controlling the humidity in the carbonization kiln to be 85-90%.
(3) Cooling and humidifying: stopping heating the carbonization kiln, and when the temperature of the carbonization kiln is above 100 ℃, spraying and steaming the carbonization kiln every 45min, wherein the spraying and steaming time is 1.0min, and controlling the humidity in the carbonization kiln to be 85-90%.
(4) Cooling balance: and after the temperature in the carbonization kiln is reduced to below 60 ℃, taking oak out of the kiln and cooling to room temperature.
Example 4
(1) Heating and heating: the teak stacked on the frame body is placed into a carbonization kiln, the frame body is sent into the carbonization kiln by adopting a conveying platform, the temperature of the carbonization kiln at room temperature is raised once until the temperature is 70 ℃, the temperature raising speed is 8 ℃/h, the carbonization kiln is required to be steamed at intervals of 60 minutes, the steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-85%. And (3) carrying out secondary heating on the carbonization kiln until the temperature is 135 ℃, wherein the heating speed is 10 ℃/h, spraying and steaming are carried out on the carbonization kiln every 60min, the spraying and steaming time is 0.7min, and the humidity in the carbonization kiln is controlled to be 85-90%. Heating the carbonization kiln for three times until the temperature is 170 ℃, the heating speed is 8 ℃/h, the carbonization kiln needs to be steamed every 60min, the steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-85%.
(2) Carbonizing: maintaining the temperature in the carbonization kiln at 170 ℃ for 4 hours, spraying and steaming the carbonization kiln every 60 minutes, wherein the spraying and steaming time is 1.0min, and controlling the humidity in the carbonization kiln to be 80-85%.
(3) Cooling and humidifying: stopping heating the carbonization kiln, and when the temperature of the carbonization kiln is above 100 ℃, spraying and steaming the carbonization kiln every 45min, wherein the spraying and steaming time is 1.0min, and controlling the humidity in the carbonization kiln to be 80-85%.
(4) Cooling balance: and (5) cooling teak to room temperature after the temperature in the carbonization kiln is reduced to below 60 ℃.
Performance testing
According to the standard: according to GB 1931-2009 method for measuring moisture content of Wood, the moisture content of the thermally treated wood of examples 1-4 was measured. The flexural strength of the heat-treated wood of examples 1 to 4 was measured according to GB/T1936.1-2009 method for flexural Strength test of wood. According to GB 1932-2009 method for measuring the dry shrinkage of Wood, the dry shrinkage of Wood after heat treatment of examples 1 to 4 was measured. According to GB 1934.2-2009 method for determining moisture swelling properties of Wood, the moisture swelling properties of the thermally treated wood of examples 1-4 were tested and the results were as follows.
Example 1: water content: 7.1%. Residual stress (tine test): 1.8%. Flexural strength: 94.2MPa (before heat treatment), 108.3MPa (after heat treatment). Air drying shrinkage: radial dry shrinkage: 0.20%, chordwise dry shrinkage: 0.65%. Air-dry rate of rise: radial wet rise rate: 0.35%, chordwise wet rise: 1.78%.
Example 2: water content: 7.4%. Residual stress (tine test): 2.7%. Flexural strength: 103.1MPa (before heat treatment), 111.3MPa (after heat treatment). Air drying shrinkage: radial dry shrinkage: 0.19%, chordwise dry shrinkage: 0.78%. Air-dry rate of rise: radial wet rise rate: 0.34%, chordwise wet rise: 1.15%.
Example 3: water content: 6.6%. Residual stress (tine test): 2.1%. Flexural strength: 110.5MPa (before heat treatment), 121.6MPa (after heat treatment). Air drying shrinkage: radial dry shrinkage: 0.14%, chordwise dry shrinkage: 0.57%. Air-dry rate of rise: radial wet rise rate: 0.26%, chordwise wet rise: 0.85%.
Example 4: water content: 6.9%. Residual stress (tine test): 2.3%. Flexural strength: 106.8MPa (before heat treatment), 117.5MPa (after heat treatment). Air drying shrinkage: radial dry shrinkage: 0.12%, chordwise dry shrinkage: 0.61%. Air-dry rate of rise: radial wet rise rate: 0.31%, chordwise wet rise rate: 1.05%.
In summary, the three-stage gradual heating method can effectively reduce cracking and deformation of the wood caused by heating at a higher speed, protect the integrity of raw materials, is beneficial to balancing the internal and external temperatures of the wood, gradually releases the internal stress of the wood, prevents uneven changes of the internal and external parts caused by overlarge temperature difference, can better control the reaction process, and is beneficial to producing carbonized wood with higher quality. The temperature and time of carbonization treatment are controlled, so that the content of hydrophilic factors in the wood can be reduced, the hygroscopicity of the wood is reduced, the stress in the wood is released, the phenomena of wood cracking or tearing are improved, the structure of the wood is stabilized, the biological durability is improved, and the mechanical properties such as the hardness, the strength and the elastic modulus of the wood can be properly increased. The two-stage cooling mode is adopted, so that the performance of the wood is stabilized, the wood is prevented from cracking due to the change of internal stress caused by the rapid change of the ambient temperature, and the production efficiency is improved. And then the wood in a relatively stable state is cooled to room temperature by adopting a natural cooling mode, so that the heat treatment efficiency is further improved.
It will be understood that equivalents and modifications will occur to those skilled in the art based on the present invention and its spirit, and all such modifications and substitutions are intended to be included within the scope of the present invention.
Claims (9)
1. A process for the heat treatment of wood, comprising the steps of:
s1, heating and raising the temperature: placing the wood stacked on the frame body into a carbonization kiln, and heating the carbonization kiln at room temperature once until the temperature is 60-70 ℃ and the heating speed is 5-10 ℃/h; carrying out secondary heating on the carbonization kiln until the temperature is 125-135 ℃ and the heating speed is 5-10 ℃/h; heating the carbonization kiln for three times until the temperature is 165-170 ℃ and the heating speed is 5-10 ℃/h;
s2, carbonization treatment: maintaining the temperature in the carbonization kiln at 165-170 ℃ for 4-4.5 h;
s3, cooling and humidifying: stopping heating the carbonization kiln, and steaming the carbonization kiln when the temperature of the carbonization kiln is above 100 ℃; when the temperature of the carbonization kiln is below 100 ℃, adding cold water to regulate humidity and cool, and stopping the machine for kiln sealing;
s4, cooling balance: and (5) when the temperature in the carbonization kiln is reduced to below 60 ℃, taking the wood out of the kiln and cooling to room temperature.
2. The process for heat treatment of wood according to claim 1, wherein in the heating and warming process, the carbonization kiln is steamed every 60min, the steaming time is 0.5-1.0 min, and the humidity in the carbonization kiln is controlled to be 80-95%.
3. The heat treatment process of wood according to claim 2, wherein the primary heating is performed for 0.5min, the secondary heating is performed for 0.7min, and the tertiary heating is performed for 1.0min.
4. The heat treatment process of wood according to claim 1, wherein in the carbonization treatment, the carbonization kiln is steamed every 60min, the steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-95%.
5. The heat treatment process of wood according to claim 1, wherein in the cooling and humidifying process, every 45min of the carbonization kiln is required to be steamed, the steaming time is 1.0min, and the humidity in the carbonization kiln is controlled to be 80-95%.
6. The heat treatment process of wood according to claim 1, wherein the target temperature of the primary heating is 65 ℃, the target temperature of the secondary heating is 130 ℃, and the target temperature of the tertiary heating is 170 ℃.
7. The heat treatment process of wood according to claim 6, wherein the temperature rising rate of the primary temperature rising is 8 ℃/h, the temperature rising rate of the secondary temperature rising is 5 ℃/h, and the temperature rising rate of the tertiary temperature rising is 6 ℃/h.
8. The process for heat treatment of wood according to claim 1, wherein the wood is naturally dried in advance to a water content of 26 to 32% before entering the carbonization kiln.
9. Wood, characterized in that it is obtained after treatment by the heat treatment process of wood according to any one of claims 1-8.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311831496.2A CN117584234A (en) | 2023-12-27 | 2023-12-27 | Heat treatment process of wood and wood |
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| CN202311831496.2A CN117584234A (en) | 2023-12-27 | 2023-12-27 | Heat treatment process of wood and wood |
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