JP2006187674A - Method and system for producing silicic acid-containing powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for producing silicic acid-containing powder, by each of which natural silicic acid-containing powder conveniently usable as a straight fertilizer can be produced by treating rice hulls and straws in a short time at a low cost without decreasing silicic acid. <P>SOLUTION: This method for producing silicic acid-containing powder from rice hulls or straws comprises the steps of injecting high-pressure steam into the rice hulls or straws thrown in a treatment vessel 2 and powdering the contents while maintaining the pressure in the treatment vessel 2 at 1.45 MPa-1.96 MPa. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In order to reuse natural silicic acid contained in rice husk, rice straw, wheat straw, etc., the present invention contains a silicic acid suitable for producing a powder containing natural silicic acid by changing the properties of the rice husk etc. The present invention relates to a powder manufacturing method and a silicic acid-containing powder manufacturing system.

  Conventionally, it is known that silicic acid is effective in strengthening rice and preventing disease. However, in recent years, the content of silicic acid in paddy fields has been on the decline, and it has become necessary to replenish silicic acid separately. At present, the mainstream of silicic acid applied to paddy fields is one that is artificially extracted from mineral materials or that uses burned rice husk charcoal. However, in practice, it is not easy to extract silicic acid. For example, when silicic acid is extracted from a mineral material, there is a problem that the ore cutting and pulverization process and other processes are complicated, which requires labor, time, and cost. In the case of rice husk charcoal, silicic acid disappears depending on the degree of carbonization and the content is considerably reduced. Of course, the processing cost is also high.

  On the other hand, rice husks and rice straw are industrial wastes, so they need to be treated properly. However, because of the cost of processing, they are often left unattended, and there is a risk of spontaneous ignition. It is given as.

  Conventionally, as a technique for effectively reusing silicic acid contained in rice husks, JP-A-8-224488 proposes an invention for pulverizing rice husks (Patent Document 1). The present invention is characterized in that dry rice husk is pulverized by an impact pulverizer, and the pulverized husk-containing composition is granulated by mixing the finely pulverized product with natural aluminosilicate or a chemical treatment product thereof. To manufacture. And silica is reduced to a paddy field by spraying this rice husk containing composition on a paddy field.

JP-A-8-224488

  However, since the invention described in Japanese Patent Laid-Open No. 8-224488 is focused on finely pulverizing processing, it is impossible to efficiently extract only silicic acid. In other words, the purity of silicic acid is low because other compositions contained in the rice husk are also included together. There is also a risk that harmful polymer compounds are contained without being treated. Further, the impact pulverizer is difficult to maintain and has a high cost burden, and the rice husk is small but has high hardness, so that the impact pulverized parts are damaged quickly. On the other hand, according to the conventional invention, a chemical substance such as natural aluminosilicate is mixed and granulated, but there is also a need to avoid giving the paddy field as much chemical substance as possible. After all, with conventional techniques, it was impossible to extract silicic acid effectively from rice husks, so most of the rice husks were incinerated.

  The present invention has been made in order to solve such problems, and is a natural material that can be used as a simple fertilizer by treating rice husks and straws in a short time and at a low cost without annihilating silicic acid. An object of the present invention is to provide a silicic acid-containing powder production method and a silicic acid-containing powder production system capable of producing a silicic acid-containing powder.

  A feature of the method for producing a silicic acid-containing powder according to the present invention is that rice husk or straw is introduced into a processing container, water vapor is injected into this processing container to increase the internal pressure and temperature, and the rice husk or soot does not burn and powder. It is in the point which processes by hold | maintaining under the water vapor | steam pressure which changes. According to such a method, the pressure on the rice husks and straws and the heating and steam hydrolysis accompanying the steam pressure compress the rice husks and straws, and then gradually reduce the pressure in the container. In this case, separation and decomposition of the binding molecules occur, resulting in a change in properties of initial carbonization and refinement of rice husks and straws.

  Moreover, in this invention, it is preferable to hold | maintain the pressure in the said processing container to 1.45 Mpa-1.96 Mpa, and to pulverize.

  Furthermore, in the present invention, in order to produce a silicic acid-containing powder more effectively, it is preferable to perform pulverization by holding the pressure in the processing vessel at 1.65 MPa to 1.85 MPa for 5 minutes to 30 minutes.

  In addition, the silicic acid-containing powder production system according to the present invention is characterized by a processing vessel provided with a stirring means, and a steam injection means for injecting pressurized water vapor into the rice husk or straw put into the processing container. And control means for controlling the amount of water vapor injected by the water vapor injecting means so as to maintain a pressure at which the rice husk or the soot in the processing vessel can be powdered without burning. According to such a configuration, the rice husk and the straw are compressed from all directions in the processing container by the action of pressure on the rice husk and the straw, and the heating and steam hydrolysis accompanying the water vapor pressure. When the pressure in the processing container is gradually reduced, the separation and decomposition of the binding molecules are started, and as a result, the property changes of initial carbonization and refinement of rice husks and straws occur.

  Furthermore, in the present invention, the control means preferably controls the amount of water vapor injected by the water vapor injection means so that the pressure in the processing container is maintained at 1.45 MPa to 1.96 MPa. It is more desirable to control so that the internal pressure is maintained at 1.65 MPa to 1.85 MPa for 5 minutes to 30 minutes.

  According to the present invention, a powder containing natural silicic acid that is easy to use as a simple fertilizer by pulverizing rice husk in a short time and at low cost without annihilating the silicic acid component contained in rice husk and straw. Can be manufactured.

  Hereinafter, a suitable embodiment of a silicic acid content powder manufacturing system concerning the present invention is described using a drawing.

  FIG. 1 is a schematic diagram showing a silicic acid-containing powder production system 1 of the present embodiment. The silicic acid-containing powder production system 1 of the present embodiment includes a processing container 2 for storing and processing rice husks and straws, and a stirring means 3 for stirring the rice husks and straws charged into the processing container 2, Steam injecting means 4 for injecting high-pressure steam into rice husks and straws in the processing container 2, pressure adjusting means 5 for adjusting the pressure in the processing container 2, stirring means 3, steam injecting means 4 And a control means 6 for controlling the pressure adjusting means 5.

  If it demonstrates in detail about each structure part of this embodiment, the processing container 2 will be comprised by the 1st type pressure vessel provided with pressure resistance, and the rice husk and straw are processed inside. The processing vessel 2 is provided with a rice husk and straw input port 21 in the upper part and a discharge port 22 in the lower part. The input port 21 and the discharge port 22 have a sealed structure capable of maintaining the pressure in the processing container 2 when processing rice husks and straws. In addition, a sealing mechanism (not shown) is provided for maintaining the sealing performance between the horizontal rotation shaft 31 of the stirring means 3 and the processing container 2 described later. In consideration of safety, the input port 21 and the discharge port 22 are provided with system control in which the opening / closing operation does not react unless the pressure in the processing container 2 reaches 0.015 MPa or less. Furthermore, the processing container 2 is provided with an upper temperature sensor 23a, a lower temperature sensor 23b, and a pressure sensor 24, and detects the temperature and pressure in the processing container 2.

  Next, the stirring means 3 is for pressurizing and heating the whole rice husk and straw. The stirring means 3 is supported by a horizontal rotation shaft 31 in the longitudinal direction in the processing container 2, and a stirring blade 32 inclined forward with respect to a vertical plane is attached to the horizontal rotation shaft 31. Has been. The horizontal rotation shaft 31 is connected to a drive motor 33 that can rotate forward and reverse. The agitating means 3 is configured to gradually transfer the introduced rice husks and straws while stirring, and extends from the inlet 21 to the outlet 22. On the other hand, the drive motor 33 is a motor whose rotation speed and rotation direction can be controlled by inverter control, and is reciprocated in the processing container 2 as needed until the rice husks and straws are pulverized into desired properties.

  Next, the water vapor injection means 4 has a boiler 41 that generates high-pressure water vapor, and an air supply pipe 42 for supplying the water vapor generated from the boiler 41 into the processing vessel 2. The pressure of water vapor generated in the boiler is maintained at a constant value, and the pressure in the processing vessel 2 is adjusted by the injection amount of high-pressure water vapor. Since the temperature is determined in association with the pressure of the high-pressure steam, the inside of the processing container 2 is kept at a high temperature. The air supply pipe 42 is connected to the processing container 2 in a substantially horizontal direction at a position above the horizontal rotation shaft 31. This is optimal when the rice husks and straws in the processing container 2 are deposited and not subjected to pressure, that is, it is agitated and floats in the hollow, and the high pressure steam is applied immediately before the rice husks and straws are covered. This is because the processing efficiency can be obtained.

  Next, the pressure adjusting means 5 includes a pressure adjusting valve 51 that can be freely opened and closed by electrical control, and an exhaust pipe 52 for exhausting water vapor in the processing container 2 through the pressure adjusting valve 51. When the pressure in the processing container 2 exceeds a predetermined value, the pressure adjusting valve 51 is opened, and the pressure in the processing container 2 is released and held at a predetermined pressure. In addition, a cooling device 8 is connected to the exhaust pipe 52 via the silencer 7, and the water vapor from the processing container 2 is cooled and liquefied and supplied to the wastewater treatment facility 9. Furthermore, the silencer 7 is designed so that the regulation value of the noise prevention regulations can be cleared and installed in an urban area or the like.

  Next, the control means 6 is electrically connected to the stirring means 3, the water vapor injection means 4, and the pressure adjusting means 5, and controls them. The control means 6 controls the rotation direction and speed of the drive motor 33 to control the time for stirring and transferring rice husks and straws in the processing container 2. The control means 6 controls the amount of water vapor injected by the water vapor injection means 4 so as to maintain a pressure for pulverizing the rice husk or the soot in the processing vessel 2 without burning. In the present embodiment, the pressure in the processing container 2 is maintained at 1.45 MPa to 1.96 MPa based on the experimental results of Examples described later. If the temperature or pressure in the processing container 2 decreases, the amount of high-pressure steam injected from the steam injection means 4 is increased to increase the temperature and pressure. On the contrary, when the temperature or pressure in the processing container 2 rises, the pressure regulating valve 51 of the pressure regulating means 5 is opened to exhaust the high-pressure steam to lower the temperature and pressure. The control means 6 is electrically connected to the temperature sensors 23a and 23b and the pressure sensor 24 in the processing container 2, and the temperature and pressure in the processing container 2 are set to predetermined values based on the detection results. Feedback control is performed so that

  Below, the silicic acid containing powder manufacturing method by the silicic acid containing powder manufacturing system 1 of this embodiment is demonstrated.

  First, rice husks and straws are introduced into the processing container 2 from the inlet 21. At this time, the pressure in the processing container 2 is set to 1.45 MPa to 1.96 MPa in advance with respect to the control means 6, and the time for holding this set pressure, the stirring time, and the inside of the container corresponding to the set pressure are set. Set each temperature. In this case, the pressure holding time is preferably set to a time for the rice husks and straws to start hydrolysis, and the stirring time is preferably set to a time sufficient for the rice husks and straws to be powdered. Further, the temperature in the container is set to a temperature associated with the theoretical pressure of water vapor.

  The rice husk and straw put into the processing container 2 are gradually transferred toward the discharge port 22 while being largely stirred by the stirring blade 32. Depending on the amount of processing, the processing may not be completed by only transferring in one direction. In this case, the drive motor 33 is reversed in the reverse direction and transferred to the input port 21 side to perform reciprocal transfer. Even if the processing container 2 is smaller than this, sufficient stirring time can be obtained.

  During this agitation, high-pressure steam is injected into the processing container 2 from the air supply pipe 42 attached above the horizontal rotation shaft 31. For this reason, when the rice husks and straws are scattered apart above the horizontal rotation shaft 31 by the stirring of the stirring means 3, high-pressure steam is effectively blown. Therefore, heating accompanying steam pressure and hydrolysis of steam are effectively advanced, and rice husks and straws are compressed.

  Further, while the rice husks and straws are being agitated, the control means 6 keeps the temperature in the processing container 2 at the set temperature based on the detection results of the temperature sensors 23 a and 23 b and the pressure sensor 24, and the pressure is 1 The water vapor injection means 4 and the pressure adjustment means 5 are controlled to maintain .45 MPa to 1.96 MPa.

  When the set pressure holding time has elapsed, the control means 6 controls the water vapor injection means 4 to stop the water vapor injection, and also controls the pressure adjustment means 5 to open the pressure adjustment valve 51. Then, the high-pressure steam in the processing container 2 is exhausted to the exhaust pipe 52, and the inside of the processing container 2 is depressurized. As a result, rice husks and straws undergo separation and decomposition of binding molecules, resulting in a change in properties such as initial carbonization and refinement. In this initial carbonization state, the silicic acid contained in the rice husks and cocoons remains with almost no disappearance. The powdered rice husks and straws are transferred to the discharge port 22 and taken out, and the discharged water is supplied to the waste water treatment facility 9 and purified.

  Next, specific examples of the present embodiment will be described. In each of the following examples, an experiment was performed to obtain conditions for obtaining a simple silicic acid fertilizer that can be easily used from rice husks in a short treatment. In this experiment, the processing result of rice husk was observed by changing the pressure in the processing container 2 and the pressure holding time. These experimental conditions and the processing results are shown in FIG. Moreover, the digital photograph image which image | photographed the shape before the process of a rice husk and after a process is shown in FIGS.

  In the experiment of this example, the processing vessel 2 having a volume of 3000 liters is used, the temperature in the vessel is maintained at around 200 ° C., which is a temperature associated with the theoretical pressure of water vapor, and the filling rate of the rice husk is 65% to 95%. % To be filled. Further, in order to stir the rice husk more uniformly, the stirring speed is 2 to 18 rpm until the value of the lower temperature sensor 23b matches the value of the upper temperature sensor 23a, and until the pressure is reduced to 0.15 MPa from the time of matching. Was 5-15 rpm.

  In Example 1, the processing was performed while the processing pressure in the processing container 2 was kept below 1.0 MPa. FIG. 4 is a rice husk treated according to the first embodiment. As a result, the shape did not change even after treatment for 10 minutes to 90 minutes, and the color was slightly changed to dark brown, and could not be processed substantially.

  Next, in Example 2, processing was performed while the processing pressure in the processing container 2 was maintained at 1.45 MPa. FIG. 5 shows the rice husk after processing. As a result, the pressure holding time was 10 to 90 minutes, and the treatment could be performed until the volume was reduced to about half. When the form of the treated rice husks was observed, it turned black, but it did not become powdered, and each rice husk was in a wrinkled state. Moreover, the moisture content of the rice husk after a process is 5.8%, showing a favorable value, and residual silicon is a sufficient content of 14.25%, and can be used as a single fertilizer.

  In Example 3, the treatment was performed while the treatment pressure in the treatment container 2 was maintained at 1.65 MPa. FIG. 6 shows the chaff after processing. As a result, the powder could be pulverized in a short time of 10 to 30 minutes. Moreover, the moisture content of the rice husk after a process is 43.5%, 11.96% of residual silicon is detected, and it has the favorable property as a simple fertilizer. By being powdered, the solubility increases and the usability as a fertilizer is improved.

  In Example 4, the processing was performed while the processing pressure in the processing container 2 was maintained at 1.85 MPa. FIG. 7 shows the chaff after processing. As a result, it was possible to process to a fine powder in an extremely short time of 5 to 10 minutes. In addition, the moisture content of the rice husk after the treatment was as low as 25.5%, and 9.56% of residual silicon was detected, indicating that the fertilizer had good properties as a single fertilizer.

  In Example 5, the process was performed while injecting water vapor to maintain the pressure in the processing container 2 at 1.96 MPa. FIG. 7 shows the chaff after processing. As a result, it was possible to process into a fine powder in a pressure holding time of 5 to 15 minutes. In addition, the moisture content of the rice husk after the treatment was 25.0%, and 9.0% of residual silicon was detected, indicating that it can be used as a single fertilizer. However, there is a decrease in residual silicon due to initial carbonization. Further, although the pressure holding time is short, it takes time to increase the pressure to this pressure, which is slightly impractical.

  Examining the experimental results of the above examples, processing conditions for containing natural silicic acid that can be realized in a short time without annihilating silicic acid to treat rice husks and easy to use as simple fertilizer It is preferable to maintain the pressure in the container 2 at 1.45 MPa or more and 1.96 MPa or less, and more preferably hold the pressure at 1.65 MPa or more and 1.85 MPa or less for 5 minutes to 30 minutes. The purpose of holding at high temperature and high pressure for a certain period of time is to add a margin condition for decomposing the rice husk. The timing for the decomposition of rice husk begins as slowly as possible, and the decomposition proceeds along the curve simultaneously with the start of the subsequent decompression. At this time, the water and water vapor contained in the rice husk are cooled, and the condensed water is diffused out of the container with the change of state from pressure to pressure, and the property is converted into a substance having an appropriate moisture content. .

  Normally, when a plant is decomposed by microorganisms in nature, it takes 6 to 36 months to reach the state of compost. According to the system of this embodiment, it can be composted in an extremely short time of about 60 to 90 minutes including the pressurization time, and can be safely processed in a sterile state.

  In addition, each structure of this embodiment is not restricted to what was mentioned above, It can change suitably.

  For example, in the present embodiment described above, the air supply pipe 42 and the exhaust pipe 52 have a separate and independent configuration, but a part of the common pipe may be used. This is because when the treated rice husk changes to a powder form, when the inside of the processing container 2 is decompressed, the powder is transmitted along with the water vapor through the exhaust pipe 52 and clogs the valve. For this reason, by using a common water vapor injection path and exhaust path, a cleaning process for removing the processing powder clogged in the valve at the time of water vapor injection is also performed. That is, as shown in FIG. 9, two routes are used for injecting water vapor from the boiler 41 into the processing container 2, and the exhaust route is also reversely sent through the two routes. A route branching to the exhaust pipe 52 is provided in the middle. An air supply valve 43 and an exhaust valve 53 are attached to the air supply pipe 42 and the exhaust pipe 52, respectively. A check valve 10 is provided in front of the boiler 41. Further, a control valve 11 for adjusting the flow rate of water vapor is provided in the common path. A switching valve 12 is provided in a path from the exhaust pipe 52 to the air supply pipe 42, and switching between steam injection and decompression exhaust is performed by the switching valve 12. That is, at the time of water vapor injection, the switching valve 12 is opened and the exhaust valve 53 of the exhaust pipe 52 is closed, so that two paths from the boiler 41 to the processing container 2 are opened. On the other hand, at the time of evacuation, the exhaust valve 53 is opened and the air supply valve 43 and the switching valve 12 are closed, so that the water vapor is exhausted from the two pipes connected to the processing container 2 and becomes one path on the way. The exhaust pipe 52 is exhausted. At this time, the processing powder may be clogged in the valve on the way, but since water vapor flows again in the direction of the processing container 2 at the next water vapor injection, cleaning is performed so as to remove the powder clogged in each valve at the same time.

It is a mimetic diagram showing an embodiment of a silicic acid content powder manufacturing system concerning the present invention. It is a table | surface which shows the process conditions and the process result of Example 1 in Example 5 in this embodiment. It is a digital photograph image which shows the rice husk before processing in each example. It is a digital photograph image which shows the rice husk after processing on the processing conditions of Example 1. FIG. It is a digital photograph image which shows the rice husk after processing by the processing conditions of Example 2. It is a digital photograph image which shows the rice husk after processing by the processing conditions of Example 3. It is a digital photograph image which shows the rice husk after processing by the processing conditions of Example 4. 10 is a digital photographic image showing rice husks processed according to the processing conditions of Example 5. It is a schematic diagram which shows the valve opening / closing system at the time of pressure increase and pressure reduction of the silicic acid-containing powder production system according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicic acid containing powder manufacturing system 2 Processing container 3 Stirring means 4 Water vapor | steam injection means 5 Pressure adjusting means 6 Control means 7 Silencer 8 Cooling device 9 Wastewater treatment equipment 10 Check valve 11 Control valve 12 Switching valve 21 Input port 22 Outlet port 23a Upper temperature sensor 23b Lower temperature sensor 24 Pressure sensor 31 Horizontal rotating shaft 32 Stirring blade 33 Drive motor 41 Boiler 42 Air supply pipe 43 Air supply valve 51 Pressure adjustment valve 52 Exhaust pipe 53 Exhaust valve

Claims (6)

  The rice husk or cocoon is put into a processing vessel, steam is injected into the processing vessel to increase the internal pressure and temperature, and the husk or cocoon is kept under the steam pressure where it is powdered without burning. A method for producing a silicic acid-containing powder. A method for producing a silicic acid-containing powder for producing a powder containing silicic acid from rice husk or straw,
Injecting pressurized water vapor into the rice husk or cocoon charged into the processing container, and maintaining the pressure in the processing container at 1.45 MPa to 1.96 MPa for pulverization Acid-containing powder production method.   3. The method for producing a silicic acid-containing powder according to claim 2, wherein the powder in the processing container is pulverized by holding the pressure in the processing container at 1.65 MPa to 1.85 MPa for 5 minutes to 30 minutes.   A processing vessel provided with stirring means, a water vapor injection means for injecting pressurized water vapor into the rice husk or straw put into the processing vessel, and the rice husk or straw in the processing vessel is pulverized without burning. And a control means for controlling the amount of water vapor injected by the water vapor injection means so as to maintain the obtained pressure.   A processing vessel provided with a stirring means, a water vapor injection means for injecting pressurized water vapor into the rice husk or straw put in the processing vessel, and an amount of water vapor injected by the water vapor injection means in the processing vessel A silicic acid-containing powder production system, characterized in that it has a control means for controlling the pressure of 1.45 MPa to 1.96 MPa.   6. The control means according to claim 5, wherein the control means controls the amount of steam injected by the steam injection means so that the pressure in the processing vessel is maintained at 1.65 MPa to 1.85 MPa for 5 minutes to 30 minutes. Silicic acid-containing powder production system.