JP5843394B2 - Method and apparatus for processing lignocellulosic material - Google Patents

Description

  The present invention relates to a method for treating a lignocellulosic material, and more specifically, a method for treating a lignocellulosic material for relatively increasing the content of cellulose by decomposing and removing hemicellulose contained in the material. About.

In recent years, as a resin molded product having a woody texture, a product made of WPC (Wood Plastic Composite) obtained by mixing a thermoplastic resin and a lignocellulosic material has been commercialized.
Here, the lignocellulosic material used as a WPC filler or plasticizer mainly contains cellulose, hemicellulose, and lignin.

Therefore, from the viewpoint of improving the compatibility with the thermoplastic resin or improving the strength of the resulting resin molded product, the lignocellulosic material has a low content of hemicellulose and a cellulose content of High is preferred.
For this reason, a technique for decomposing and removing hemicellulose by heat-treating lignocellulosic material with water vapor has been introduced.

  For example, Patent Document 1 below introduces a method of performing a heat treatment by exposing a lignocellulosic material to water vapor heated to 150 to 230 ° C. under high pressure in a pressure vessel.

Patent Document 2 below introduces a method for heat-treating a lignocellulosic material with superheated steam at 180 to 230 ° C. in a normal pressure atmosphere.
In the heat treatment performed at normal pressure using superheated steam as in the method described in Patent Document 2, the temperature of the material does not exceed 100 ° C. until all the water contained in the lignocellulosic material is evaporated. Hydrolysis hardly occurs (see paragraph number 0022 of the same document).
For this reason, the lignocellulosic material subjected to the heat treatment with superheated steam is usually subjected to a drying treatment as a previous step to reduce the moisture in the material to some extent.

JP 2003-165844 A JP 2011-161835 A

However, since the steam treatment described in Patent Document 1 is performed under high pressure, a large-scale facility including a pressure vessel is required.
On the other hand, since the steam treatment described in Patent Document 2 is performed in an atmospheric pressure atmosphere, it can be performed with relatively simple equipment.

  However, when the heat treatment described in Patent Document 2 is performed at an actual production scale (for example, the processing amount is 1 ton / batch), all moisture contained in the material is evaporated, and the temperature is 100 ° C. It takes a very long time to exceed the above, which not only results in excessive power consumption, but also causes a problem that hemicellulose cannot be sufficiently removed even if such heat treatment is performed. .

In other words, when it is carried out on an actual production scale, not only the water in the material charged in a large amount in the processing container (normally about 20% of water is included even after the drying process), but also overheating. Since a large amount of water generated by the condensation of water vapor (water evaporation and condensation of superheated steam proceed simultaneously during processing) exists in the processing container, all the water in the container is converted to the thermal energy of the superheated steam. Evaporation takes a very long time. For example, even if superheated steam is introduced for more than 10 hours, the water in the processing container may not be completely evaporated. In such a case, the temperature in the processing container (material) cannot be raised to the decomposable temperature of hemicellulose (usually 180 ° C or higher), or it can be decomposed because it took a long time to raise the temperature. Since the reaction time after reaching the temperature cannot be secured sufficiently, hemicellulose cannot be sufficiently decomposed and removed.
In addition, in order to generate superheated steam (generate steam and superheat it), a large amount of energy (electric power) is required, and the cost of introducing such superheated steam over a long period of time is extremely high. It will be expensive.

In the heat treatment of the lignocellulosic material, the decomposition temperature of hemicellulose is usually 180 to 320 ° C. On the other hand, the decomposition temperature of cellulose is set to 240 to 400 ° C.
Therefore, the processing temperature range in which only hemicellulose can be decomposed and removed without decomposing cellulose is relatively narrow at 180 to 240 ° C.

  However, when the heat treatment described in Patent Document 2 is performed on an actual production scale, it is difficult to maintain the temperature of all the materials charged in the processing container in the range of 180 to 240 ° C. For example, even if 180 ° C. superheated steam is introduced into the processing vessel, it is a part of the material disposed near the superheated steam inlet that raises the temperature to 180 ° C. In such a case, Since hemicellulose in the material that has not reached 180 ° C. is not substantially decomposed and removed, hemicellulose cannot be efficiently decomposed and removed as the whole material.

  As described above, when the heat treatment is performed on the actual production scale, the variation in the (material) temperature in the processing container, which was not a problem in the lab scale processing (for example, the processing amount is less than 50 kg / batch), Even if the temperature (inlet temperature) of the superheated steam introduced into the processing container is controlled, sufficient processing (decomposition of hemicellulose) cannot be realized.

The present invention has been made based on the above situation.
An object of the present invention is to provide a method for treating a lignocellulosic material capable of selectively and efficiently decomposing and removing hemicellulose contained in a material even when it is treated on an actual production scale. .
Another object of the present invention is to provide a method for treating a lignocellulosic material that can be processed with less power consumption than conventional methods.
Still another object of the present invention is to provide a lignocellulosic material processing apparatus capable of selectively and efficiently decomposing and removing hemicellulose contained in a charged material even when processing on an actual production scale. Is to provide.

(1) The method for treating a lignocellulosic material of the present invention is a method for treating a lignocellulosic material for decomposing and removing hemicellulose contained in the material,
Charging lignocellulosic material into a processing vessel;
A step (primary heating step) of heating the lignocellulosic material by introducing heated air at 240 to 300 ° C. into the processing vessel;
When the exhaust temperature (T _ex ) from the processing container reaches a temperature (T ₁ ) within the range of 120 to 180 ° C., superheated steam at 240 to 300 ° C. is introduced into the processing container instead of heated air. And a step of further heating the lignocellulosic material (secondary heating step) while controlling the exhaust temperature (T _ex ) from the processing vessel to be 200 to 240 ° C.

  According to such a processing method, the temperature in the processing container (material temperature) can be adjusted even when processing at the actual production scale by performing the heat processing with heated air prior to the heat processing with superheated steam. It can be raised in a short time. Thereby, the reaction time after reaching the decomposable temperature of hemicellulose can be secured sufficiently. Further, since the amount of power required for generating heated air is much lower than the amount of power required for generating superheated steam at the same temperature, the power consumption required for the entire process can be sufficiently reduced.

In the secondary heating process, not the temperature of the superheated steam (inlet temperature) introduced into the processing container but the exhaust temperature (outlet temperature) from the processing container is controlled to 200 to 240 ° C. so that it is charged into the processing container. All the materials can be set to a temperature approximately equal to the exhaust temperature (T _ex ) (a temperature at which hemicellulose can be decomposed and cellulose cannot be decomposed).

Furthermore, when the exhaust temperature (T _ex ) reaches a temperature (T ₁ ) within the range of 120 to 180 ° C., the heat treatment with heated air (primary heating step) to the heat treatment with secondary steam (secondary heating step). For the first time, by selectively and efficiently decomposing and removing the hemicellulose contained in the material charged in the processing vessel (by setting the switching temperature (T ₁ ) in the range of 120 to 180 ° C.). Can do.

(2) In the processing method of this invention, it is preferable that the mass of the material charged into the said processing container is 50 kg or more.

(3) In the treatment method of the present invention, it is preferable that the long lignocellulosic material is arranged vertically while ensuring a gap that becomes a flow path of superheated air and superheated steam from above to below.
Superheated air and superheated steam are usually introduced from below in the processing vessel and discharged from above. In such a processing container, the flow path of superheated air and superheated steam is ensured, whereby variation in (material) temperature in the processing container can be suppressed.

(4) In the processing method of this invention, it is preferable that the said lignocellulosic material consists of raw bamboo.

(5) The processing apparatus of the present invention is a processing apparatus used for carrying out the processing method of the present invention,
A processing container charged with lignocellulosic material;
A superheater that generates heated air and superheated steam to be introduced into the processing vessel;
A compressor for supplying air to the superheater to generate heated air;
A boiler for supplying steam to the superheater to generate superheated steam;
Connected to the compressor via a first flow path, connected to the boiler via a second flow path, connected to the superheater via a common flow path, and either the compressor or the boiler was connected to the boiler A three-way solenoid valve that switches to connect to the superheater,
A temperature sensor for measuring an exhaust temperature (T _ex ) from the processing container;
The superheater is turned on / off according to the exhaust gas temperature (T _ex ) measured by the temperature sensor, and the measured exhaust gas temperature (T _ex ) is within a range of 120 to 180 ° C. When lower than T ₁ ), the first flow path is opened to connect the compressor to the superheater, and after the measured exhaust temperature (T _ex ) reaches the temperature (T ₁ ), the second flow And a control unit that controls the three-way solenoid valve so as to open a path and connect the boiler to the superheater.

(6) In the processing apparatus of the present invention, the control unit outputs an off signal to the power supply of the superheater when the exhaust temperature (T _ex ) measured by the temperature sensor exceeds 240 ° C. It is preferable to output an ON signal to the power supply of the superheater when (T _ex ) becomes less than 200 ° C.

According to the processing method of the present invention, hemicellulose contained in a material can be selectively and efficiently decomposed and removed even when processing on an actual production scale.
Moreover, processing can be performed with less power consumption than conventional methods.
According to the processing apparatus of the present invention, hemicellulose contained in the charged material can be selectively and efficiently decomposed and removed even when processing on an actual production scale.

It is a block diagram which shows one Embodiment of the processing apparatus of this invention. It is a TG-DTA curve measured about the sample (raw bamboo) which is not processed. 3 is a TG-DTA curve measured for a sample treated in Comparative Example 1. 4 is a TG-DTA curve measured for a sample treated in Comparative Example 2. 2 is a TG-DTA curve measured for a sample treated in Example 1. FIG. 3 is a TG-DTA curve measured for a sample treated in Example 2. 3 is a TG-DTA curve measured for a sample treated in Example 3. FIG. 6 is a TG-DTA curve measured for a sample treated in Comparative Example 3. It is a TG-DTA curve measured about the sample processed by comparative example 4. In each of Example 4 and Comparative Example 5, it is a temperature curve showing the exhaust temperature from the processing vessel and the material temperature over time.

Hereinafter, the processing method and the processing apparatus of the present invention will be described in detail.
The method for treating a lignocellulosic material of the present invention is a treatment method for relatively increasing the content ratio of cellulose by decomposing and removing hemicellulose contained in the material. Here, examples of the lignocellulosic material include plants, for example, woods such as conifers and broad-leaved trees, and herbs such as bamboo and rice straw. Of these, raw bamboo is preferably used.

The processing method of the present invention is processed by a processing apparatus having a configuration as shown in FIG.
This processing apparatus includes a processing container 10 in which lignocellulosic material is charged, a superheater (superheater) 20 that generates heated air and superheated steam introduced into the processing container 10, and a superheater that generates heated air. 20 is connected to the compressor 30 via the first flow path 51 and the compressor 30 is supplied to the superheater 20 to generate superheated steam. Connected to the boiler 40, connected to the superheater 20 via the common flow path 53, one of the first flow path 51 and the second flow path 52 is in an “open” state, and the other is in a “closed” state. By doing this, the three-way solenoid valve 50 that switches so that either the compressor 30 or the boiler 40 is connected to the superheater 20, and the temperature at which the exhaust temperature (T _ex ) from the processing vessel 10 is measured. The on / off control of the power source 25 of the superheater 20 is performed according to the temperature sensor 60 and the exhaust temperature (T _ex ) measured by the temperature sensor 60, and the exhaust temperature (T _ex ) is in the range of 120 to 180 ° C. When the temperature is lower than the internal temperature (T ₁ ), the compressor 30 is connected to the superheater 20 with the first flow path 51 being “open” so that heated air is generated by the superheater 20, and the exhaust temperature (T _ex ). After the temperature reaches the temperature (T ₁ ), the three-way solenoid valve 50 is connected so that the boiler 40 is connected to the superheater 20 with the second flow path 52 in an “open” state so that superheated steam is generated by the superheater 20. And a control unit 70 for controlling the above.

  Heated gas (heated air / superheated steam) generated by the superheater 20 is introduced into the processing container 10. The heated fluid introduced into the processing container 10 flows in the processing container 10 from below to above and is discharged from an exhaust port provided in the ceiling.

The superheater 20 heats the air supplied from the compressor 30 by electromagnetic induction to generate heated air, and heats (superheats) the steam supplied from the boiler 40 by electromagnetic induction to generate superheated steam.
The amount of air supplied from the compressor 30 to the superheater 20 (amount of heated air) and the amount of water vapor supplied from the boiler 40 to the superheater 20 (amount of superheated steam) are determined by the amount of lignocellulosic material charged. It can be adjusted accordingly.

  Note that either one of air and water vapor is supplied to the superheater 20. Therefore, one of heated air and superheated steam is generated from the superheater 20 and introduced into the processing vessel 10. That is, in the three-way solenoid valve 50, when the first flow path 51 is in the “open” state (the second flow path 52 is in the “closed” state), air is supplied to the superheater 20, Heated air from the superheater 20 is introduced. On the other hand, when the second channel 52 is in the “open” state (the first channel 51 is in the “closed” state), water vapor is supplied to the superheater 20, and the processing vessel 10 is overheated from the superheater 20. Steam is introduced. Note that the common flow path 53 connecting the three-way solenoid valve 50 and the superheater 20 is always in the “open” state.

The temperature sensor 60 measures the exhaust temperature (T _ex ) from the processing container 10 and sends information related to the exhaust temperature (T _ex ) to the control unit 70.

When the exhaust gas temperature (T _ex ) is lower than the temperature (T ₁ ) in the range of 120 to 180 ° C., the control unit 70 sets the first flow path 51 to the “open” state and air from the compressor 30 to the superheater 20. After the exhaust gas temperature (T _ex ) reaches (T ₁ ), the second flow path 52 is set to the “open” state, and the boiler 40 is connected to the superheater. The three-way solenoid valve 50 is controlled so as to enable supply of water vapor to 20 (generation of superheated water vapor by the superheater 20).

In addition, when the exhaust temperature (T _ex ) measured by the temperature sensor 60 exceeds 240 ° C., the control unit 70 outputs an off signal to the power supply 25 of the superheater 20 and the exhaust temperature (T _ex ) is less than 200 ° C. When this happens, an ON signal is output to the power supply 25 of the superheater 20 to perform on / off control of the power supply 25 of the superheater 20 in accordance with the exhaust temperature (T _ex ).

In the treatment method of the present invention performed using the above-described treatment apparatus, the step of charging the lignocellulosic material into the treatment vessel 10 and the heating air of 240 to 300 ° C. are introduced into the treatment vessel 10 from the superheater 20 to lignocellulose When the primary heating process for heating the material and the exhaust temperature (T _ex ) from the processing vessel 10 measured by the temperature sensor 60 reach a temperature (T ₁ ) in the range of 120 to 180 ° C., heated air Instead, superheated steam at 240 to 300 ° C. is introduced from the superheater 20 into the processing vessel 10, and the superheater 20 is controlled by the control unit 70 so that the exhaust temperature (T _ex ) from the processing vessel 10 becomes 200 to 240 ° C. A secondary heating step of further heating the lignocellulosic material while controlling the power source 25 of the battery.

  When the lignocellulosic material is charged into the processing vessel 10, a long lignocellulosic material (such as raw bamboo) may be arranged vertically while ensuring a gap that becomes a flow path for superheated air and superheated steam. preferable. Thereby, in the processing container 10, the flow path of the superheated air and superheated water vapor | steam which goes upwards from the downward direction is ensured, and the variation in the material temperature in the processing container 10 can be suppressed.

The amount of lignocellulosic material charged is preferably 50 kg or more, more preferably 100 kg or more, and 300 kg if a suitable example is shown.
The processing method of the present invention is effective in processing on an actual production scale in which a material of 50 kg or more is processed.

The primary heating step is a step of heating the lignocellulosic material by introducing heated air from the superheater 20 into the processing vessel 10.
This heated air is generated by heating the air supplied from the compressor 30 to the superheater 20 with the superheater 20 (electromagnetic induction heating).

In the primary heating step, the temperature of the heated air to be introduced (inlet temperature) is 240 to 300 ° C. When the temperature of the heated air is less than 240 ° C., the temperature raising time cannot be shortened sufficiently.
On the other hand, when the temperature of the heated air exceeds 300 ° C., the temperature of the lignocellulosic material (particularly, the material disposed in the vicinity of the inlet) in the processing container becomes excessive, and the material may be carbonized. .

The introduction amount of heated air, varies depending charge of lignocellulosic materials, e.g., 55m ³ if Shimese preferably 30~200m a ³ / h when the charged amount is 300 kg, a preferable example / H.

The heated air introduced into the processing container 10 is provided on the ceiling by heating the material by flowing upward from below along the long lignocellulosic material arranged vertically. It is discharged from the exhaust port.
Here, the exhaust temperature (T _ex ) from the processing container 10 is measured by the temperature sensor 60, and information related to the exhaust temperature is sent from the temperature sensor 60 to the control unit 70.

When the exhaust temperature (T _ex ) measured by the temperature sensor 60 reaches a temperature (T ₁ ) within the range of 120 to 180 ° C., the secondary heating process is performed.
This secondary heating step is a step of further heating the lignocellulosic material by introducing superheated steam from the superheater 20 into the processing vessel 10.
The superheated steam is generated by heating the steam supplied from the boiler 40 to the superheater 20 with the superheater 20 (electromagnetic induction heating).

In the secondary heating step, the temperature of the superheated steam to be introduced (inlet temperature) is 240 to 300 ° C. When the temperature of the superheated steam is less than 240 ° C., depending on the amount of lignocellulosic material charged, it becomes difficult to raise the temperature of all the materials arranged in the processing container to a temperature at which hemicellulose can be decomposed. .
On the other hand, when the temperature of the heated air exceeds 300 ° C., the temperature of the lignocellulosic material in the processing container (particularly, the material disposed in the vicinity of the inlet) becomes excessive, and the cellulose raw material contained in the material There is a risk of decomposition or carbonization of the material.

  The amount of superheated steam introduced varies depending on the amount of lignocellulosic material charged. For example, when the amount charged is 300 kg, it is preferably 30 to 150 kg / h, and a suitable example is 130 kg / h. It is.

In the secondary heating step, the lignocellulosic material is further heated while controlling the power supply 25 of the superheater 20 by the control unit 70 so that the exhaust temperature (T _ex ) from the processing vessel 10 becomes 200 to 240 ° C.
By heating while controlling the exhaust temperature (T _ex ) from the processing container 10, all the materials charged in the processing container 10 can be decomposed to a temperature (hemicellulose can be decomposed) substantially equal to the exhaust temperature (T _ex ). And the temperature at which the cellulose does not decompose).

When the exhaust temperature in the secondary heating step is less than 200 ° C., depending on the amount of lignocellulosic material charged, all the materials placed in the processing vessel may be heated to a temperature at which hemicellulose can be decomposed. It becomes difficult.
On the other hand, when the exhaust gas temperature exceeds 240 ° C., cellulose contained in the material may be decomposed.

In the present invention, the exhaust temperature (T _ex ) [switching temperature (T ₁ )] when switching from heat treatment with heated air (primary heating step) to heat treatment with superheated steam (secondary heating step) is 120 to 180. ℃.
When the exhaust temperature when switching to the heat treatment with superheated steam is less than 120 ° C., it is not possible to sufficiently shorten the heating time and reduce the power consumption, and hemicellulose contained in the material Cannot be sufficiently decomposed and removed (see Comparative Example 2 described later).
On the other hand, when the exhaust temperature when switching to heat treatment with superheated steam exceeds 180 ° C., there is a possibility that a decomposition reaction of cellulose occurs (see Comparative Example 3 described later).

According to the treatment method of the present invention, even if the treatment is performed on an actual production scale by performing the heat treatment (primary heating step) using heated air prior to the heat treatment using the superheated steam (secondary heating step). The temperature (material temperature) in the processing container can be increased to a temperature exceeding 100 ° C. in a short time.
That is, by performing heat treatment with heated air in the primary heating step, moisture in the material can be efficiently evaporated, and when the material is heated with heated air, it occurs when heated with superheated steam. Since no condensed water is generated, the water present in the processing vessel 10 can be evaporated in a short time.
Thus, according to the manufacturing method of the present invention in which heat treatment with heated air (primary heating step) is performed, the temperature (material temperature) in the processing vessel 10 is compared with the case of performing heat treatment with superheated steam from the beginning. The reaction time after reaching the decomposable temperature of hemicellulose can be sufficiently secured by shortening the temperature raising time.
Further, it is not necessary to dry the lignocellulosic material prior to the primary heating step. Furthermore, the amount of power required to generate heated air is much lower than the amount of power required to generate superheated steam at the same temperature, and coupled with the shortening of the heating time, the entire process (primary heating step / secondary heating step) ) Can be sufficiently reduced in power consumption.

In the secondary heating step, the exhaust temperature (T _ex ) (outlet temperature) from the processing container 10 is controlled to 200 to 240 ° C., so that all materials charged in the processing container The temperature can be approximately equal to (T _ex ) (temperature at which hemicellulose can be decomposed and cellulose is not decomposed).

Furthermore, when the exhaust temperature (T _ex ) reaches a temperature (T ₁ ) within the range of 120 to 180 ° C., the heat treatment with heated air (primary heating step) to the heat treatment with secondary steam (secondary heating step). ) (The switching temperature (T ₁ ) is set in the range of 120 to 180 ° C.), so that the hemicellulose is decomposed and removed without decomposing the cellulose contained in the material, that is, the hemicellulose is selectively used. And can be efficiently decomposed and removed.

<Example 1>
Using a processing apparatus as shown in FIG. 1, 300 kg of lignocellulosic material made of raw bamboo is placed in a processing vessel 10 (indoor dimensions: 1220 mm × 2440 mm × 1220 mmH) and a flow path of superheated air and superheated steam. It was placed vertically so that a gap could be secured.
Next, as a primary heating step, the lignocellulosic material was heated by introducing heated air of 240 to 300 ° C. into the processing vessel 10. In this Example 1 and the following Examples and Comparative Examples, the amount of heated air introduced was 55 m ³ / h.
At the time when 1 hour has passed since the start of heating (at this time, the exhaust temperature (T _ex ) measured by the temperature sensor 60 was 120 ° C.), as a secondary heating step, 240-200 instead of heated air was used. Lignocellulose is introduced while controlling the power supply 25 of the superheater 20 by the control unit 70 so that superheated steam at 300 ° C. is introduced into the processing vessel 10 and the exhaust temperature (T _ex ) from the processing vessel 10 becomes 200 to 240 ° C. The system material was heated for an additional 5 hours to complete the process. In this Example 1 and the following Examples and Comparative Examples, the amount of superheated steam introduced was 130 kg / h.
For each of the material treated and the untreated material according to Example 1, a differential thermal-thermogravimetric analysis (TG-DTA) was performed, and a DTG curve and a mass reduction rate curve were measured. The results for the untreated material are shown in FIG. 2, and the results for the treated material are shown in FIG.

<Example 2>
In the same manner as in Example 1, 300 kg of lignocellulosic material was charged into the processing vessel 10 and, according to the conditions shown in Table 1 below, heated air at 240 to 300 ° C. was introduced into the processing vessel 10 as a primary heating step. The lignocellulosic material is heated by the second heating step at the time when 3 hours have passed since the heating was started (at this time, the exhaust temperature (T _ex ) measured by the temperature sensor 60 was 150 ° C.). As described above, superheated steam of 240 to 300 ° C. is introduced into the processing container 10 instead of heated air, and the superheater 20 is controlled by the control unit 70 so that the exhaust temperature (T _ex ) from the processing container 10 becomes 200 to 240 ° C. The lignocellulosic material was further heated for 3 hours while controlling the power source 25 of the battery to complete the treatment.
With respect to the material treated according to Example 2, a DTG curve and a mass decrease rate curve were measured. The results are shown in FIG.

<Example 3>
In the same manner as in Example 1, 300 kg of lignocellulosic material was charged into the processing vessel 10 and, according to the conditions shown in Table 1 below, heated air at 240 to 300 ° C. was introduced into the processing vessel 10 as a primary heating step. The lignocellulosic material is heated by the secondary heating process at the time when 4 hours have passed since the heating was started (at this time, the exhaust temperature (T _ex ) measured by the temperature sensor 60 was 180 ° C.). As described above, superheated steam of 240 to 300 ° C. is introduced into the processing container 10 instead of heated air, and the superheater 20 is controlled by the control unit 70 so that the exhaust temperature (T _ex ) from the processing container 10 becomes 200 to 240 ° C. The lignocellulosic material was further heated for 2 hours while controlling the power supply 25 of the battery to complete the treatment.
For the material treated according to Example 3, the DTG curve and the mass loss rate curve were measured. The results are shown in FIG.

<Comparative Example 1>
In the same manner as in Example 1, 300 kg of lignocellulosic material was charged into the processing vessel 10, and superheated steam at 240 to 300 ° C. was introduced into the processing vessel 10 according to the conditions shown in Table 1 below. The treatment was completed by heating for 6 hours.
The comparative example 1 is a comparative example in which the heat treatment with heated air (primary heating step) was not performed. With respect to the material treated according to Comparative Example 1, a DTG curve and a mass reduction rate curve were measured. The results are shown in FIG.

<Comparative Example 2>
In the same manner as in Example 1, 300 kg of lignocellulosic material was charged into the processing vessel 10, and heated air at 240 to 300 ° C. was introduced into the processing vessel 10 according to the conditions shown in Table 1 below. At the time when 30 minutes have passed since the heating was started (at this time, the exhaust temperature (T _ex ) measured by the temperature sensor 60 was 105 ° C.), the heating air was replaced by 240 to 300 ° C. The superheated steam was introduced into the processing vessel 10 and the lignocellulosic material was further heated for 5 hours 30 minutes to complete the processing.
The comparative example 2 is a comparative example in which the heat treatment with heated air is switched to the heat treatment with superheated steam at a stage where the exhaust temperature (T _ex ) does not reach 120 ° C. With respect to the material treated according to Comparative Example 2, a DTG curve and a mass reduction rate curve were measured. The results are shown in FIG.

<Comparative Example 3>
In the same manner as in Example 1, 300 kg of lignocellulosic material was charged into the processing vessel 10, and heated air at 240 to 300 ° C. was introduced into the processing vessel 10 according to the conditions shown in Table 1 below. At the time when 5 hours have passed since the heating was started (at this time, the exhaust temperature (T _ex ) measured by the temperature sensor 60 was 200 ° C.), the heating air was replaced by 240 to 300 ° C. Of superheated steam is introduced into the processing vessel 10 and the control unit 70 controls the power supply 25 of the superheater 20 so that the exhaust temperature (T _ex ) from the processing vessel 10 is 200 to 240 ° C. Was heated for an additional hour to complete the treatment.
In this comparative example 3, after the exhaust temperature (T _ex ) exceeds 180 ° C., the heat treatment with heated air is switched to the heat treatment with superheated steam. With respect to the material treated according to Comparative Example 3, a DTG curve and a mass reduction rate curve were measured. The results are shown in FIG.

<Comparative Example 4>
In the same manner as in Example 1, 300 kg of lignocellulosic material was charged into the processing container 10, and heated air at 240 to 300 ° C. was introduced into the processing container 10 according to the conditions shown in Table 1 below. The lignocellulosic material was heated for 6 hours while controlling the power source 25 of the superheater 20 by the controller 70 so that the exhaust temperature (T _ex ) was 200 to 240 ° C., and the treatment was completed.
The comparative example 4 is a comparative example in which only the heat treatment with heated air is performed and the heat treatment with superheated steam is not performed. With respect to the material treated according to Comparative Example 4, a DTG curve and a mass reduction rate curve were measured. The results are shown in FIG.

<Example 4>
In accordance with the requirements shown in Table 1 below, the lignocellulosic material was treated in the same manner as in Example 2 except that the heating time in the secondary heating step was changed to 4 hours.
FIG. 10 shows temporal changes in the exhaust temperature (T _ex ) from the processing container 10 and the material temperature (temperature measured by a temperature sensor attached to the lignocellulosic material disposed in the processing container 10) in Example 4. .
As shown in FIG. 10, the exhaust temperature (T _ex ) and the material temperature in the secondary heating step are very close to each other, and this is the same for the temperature of the material arranged at any position in the processing vessel 10. Met.

<Comparative Example 5>
In accordance with the requirements shown in Table 1 below, the lignocellulosic material was treated in the same manner as in Comparative Example 1 except that the heat treatment time with superheated steam was changed to 7 hours.
In this comparative example 5, the time-dependent change of the material temperature in the processing container 10 is combined with FIG. As shown in FIG. 10, the material temperature was maintained at 100 ° C. for 7 hours.

  The DTG curves (FIGS. 5 to 7) relating to the materials treated according to Examples 1 to 3 all have low DTG values at 180 to 240 ° C., which is the decomposition temperature of hemicellulose, and the decomposition temperature of cellulose. A large peak is observed at a certain 240 to 400 ° C. Thus, according to the processing methods according to Examples 1 to 3, hemicellulose could be selectively and efficiently decomposed and removed.

  On the other hand, the DTG curve (FIG. 3) concerning the material processed by the comparative example 1 which did not perform the heat processing by heated air, It switched to the heat processing by superheated steam in the stage where exhaust temperature has not reached 120 degreeC. The DTG curve (FIG. 4) concerning the material processed by the comparative example 2 compares the value of DTG in 180-240 degreeC which is the decomposition temperature of hemicellulose with the DTG curve shown in FIGS. The hemicellulose contained in the material could not be sufficiently decomposed by the treatment methods according to Comparative Examples 1 and 2.

  Further, after the exhaust gas temperature exceeded 180 ° C., the DTG curve (FIG. 8) relating to the material treated in Comparative Example 3 switched to the heat treatment with superheated steam, the treatment in Comparative Example 4 in which only the heat treatment with heated air was performed. The DTG curve (FIG. 9) relating to the material made has a low peak at 240 to 400 ° C., which is the decomposition temperature of cellulose, and depending on the treatment method according to Comparative Examples 3 to 4, it is decomposed to cellulose, The hemicellulose contained in the material could not be selectively decomposed.

DESCRIPTION OF SYMBOLS 10 Processing container 20 Superheater 30 Compressor 40 Boiler 50 Three-way solenoid valve 51 1st flow path 52 2nd flow path 53 Common flow path 60 Temperature sensor 70 Control part

Claims (6)

A method for treating a lignocellulosic material for decomposing and removing hemicellulose contained in a material,
Charging lignocellulosic material into a processing vessel;
Heating the lignocellulosic material by introducing heated air at 240 to 300 ° C. into the processing vessel;
When the exhaust temperature (T _ex ) from the processing container reaches a temperature (T ₁ ) within the range of 120 to 180 ° C., superheated steam at 240 to 300 ° C. is introduced into the processing container instead of heated air. And a step of further heating the lignocellulosic material while controlling the exhaust temperature (T _ex ) from the processing vessel to be 200 to 240 ° C.   The method for treating a lignocellulosic material according to claim 1, wherein the mass of the material charged in the treatment container is 50 kg or more.   3. The lignocellulose according to claim 1 or 2, wherein a long lignocellulosic material is arranged vertically while ensuring a gap that becomes a flow path of superheated air and superheated steam from above to below. Method of processing system material.   The method for treating a lignocellulosic material according to any one of claims 1 to 3, wherein the lignocellulosic material comprises raw bamboo. A processing apparatus used for carrying out the processing method according to claim 1, comprising:
A processing container charged with lignocellulosic material;
A superheater that generates heated air and superheated steam to be introduced into the processing vessel;
A compressor for supplying air to the superheater to generate heated air;
A boiler for supplying steam to the superheater to generate superheated steam;
Connected to the compressor via a first flow path, connected to the boiler via a second flow path, connected to the superheater via a common flow path, and either the compressor or the boiler was connected to the boiler A three-way solenoid valve that switches to connect to the superheater,
A temperature sensor for measuring an exhaust temperature (T _ex ) from the processing container;
The superheater is turned on / off according to the exhaust gas temperature (T _ex ) measured by the temperature sensor, and the measured exhaust gas temperature (T _ex ) is within a range of 120 to 180 ° C. When lower than T ₁ ), the first flow path is opened to connect the compressor to the superheater, and after the measured exhaust temperature (T _ex ) reaches the temperature (T ₁ ), the second flow A controller that controls the three-way solenoid valve to open a path and connect the boiler to the superheater;
An apparatus for processing a lignocellulosic material, comprising: The controller outputs an off signal to the power supply of the superheater when the exhaust temperature (T _ex ) measured by the temperature sensor exceeds 240 ° C., and the exhaust temperature (T _ex ) becomes less than 200 ° C. 6. The apparatus for treating a lignocellulosic material according to claim 5, wherein an on signal is output to a power source of the superheater at a time.

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