JP3714674B1 - Modified material such as rice husk and method for producing modified material such as rice husk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use rice husks, rice husks and the like, which have been difficult to reuse, as various high-value-added materials, and particularly suitable as a high-quality moisture adjusting material, snow melting material, etc. Provided is a method for producing a modified material and a modified material such as rice husk.
The rice husk or cocoon is mixed with a calcium hydroxide source, and the husk or cocoon is treated under a predetermined water vapor pressure that does not cause the rice husk or cocoon to burn. In this case, it is desirable to treat rice husks or straws under a water vapor pressure of 1.45 MPa or more.
[Selection] Figure 1

Description

  The present invention relates to rice husks, rice straws, wheat straws and other modified materials whose properties have been changed to reuse them, and a method for producing the same, and in particular, to adjust the moisture content of high-humidity wastes such as marine waste and sewage sludge. The present invention relates to a modified material such as rice husk suitable for use as a moisture adjusting material, a snow melting material, a soil improving material or the like, and a method for producing the same.

  Conventionally, when producing high-humidity waste such as raw garbage, sewage sludge and livestock manure to produce compost etc., moisture content is reduced by using a moisture adjusting material such as sawdust, and the moisture content To be adjusted. For example, Japanese Patent Laid-Open No. 9-85220 proposes an invention in which sawdust is used as a moisture adjusting material when composting raw garbage and the moisture content of the contents in the treatment tank is maintained at a desired value. (Patent Document 1). As described above, sawdust is the most common moisture-adjusting material, but other moisture-adjusting materials have been proposed. For example, JP-A 2001-294498 discloses a gypsum board as a water-adjusting material for cow manure. An invention using paper in waste materials has been proposed (Patent Document 2).

Japanese Patent Laid-Open No. 9-85220 JP 2001-294696 A

  However, it is not easy to separate only paper from gypsum board waste, which is not practical because it is expensive. On the other hand, sawdust is advantageous in that it is easy to use and has a large amount of circulation, but it is not only used as a moisture adjusting material, but also laid in cowsheds and pig houses, and also used as livestock feed. For this reason, there are problems that it is difficult to obtain and the price is rising. In addition, since the utility value of sawdust increases, there is a concern about an increase in environmental load due to destruction of forests to produce sawdust.

  On the other hand, rice husks and straws are known as one of the wastes that are difficult to reuse. Since these rice husks and straws are industrial wastes, they need to be treated properly. However, the rice husks and straws contain a silicic acid component, so they are hard and difficult to reuse, and the processing costs also increase. There is a problem that it ends up. For this reason, it is left as it is, or pollution caused by incineration is regarded as a problem.

  The present invention has been made to solve such problems, and can effectively use rice husks, straws and the like as high-value-added materials in various ways. It is an object of the present invention to provide a modified material such as rice husk suitable as a material and a method for producing a modified material such as rice husk.

  The inventor of the present application has already applied for a patent for an invention for producing a silicic acid-containing powder by subjecting rice husk or rice cake to high-pressure steam treatment in Japanese Patent Application No. 2003-302971. Mixing calcium hydroxide source such as slaked lime or scallop powder and processing under predetermined steam pressure that does not burn the rice husk or cocoon, so that the properties of rice husk and cocoon are soft like cotton fiber and have high water absorption I found a technology to change the properties. Here, the calcium hydroxide source refers to all substances that can become calcium hydroxide in the process of modifying rice husk or straw. Specifically, not only calcium hydroxide (so-called slaked lime) but also calcium oxide (so-called quicklime) that reacts with water to generate calcium hydroxide, and calcium carbonate (the main component of shells) that generates this calcium oxide by thermal decomposition. ) Etc. also fall under this category.

  In the present invention, it is preferable to treat rice husks or straws under a water vapor pressure of 1.45 MPa or more.

  In addition, the method for producing a modified material such as rice husk according to the present invention is characterized by mixing rice husk or rice husk and a calcium hydroxide source in a processing container, and injecting water vapor at a predetermined pressure into the processing container to adjust the internal pressure and temperature. The process is to raise and hold the rice husk or soot under a steam pressure that does not burn.

Moreover, in this invention, when the alkalinity is 65-80%, it is preferable that the said calcium hydroxide source is thrown in in the ratio of 6 weight% or more with respect to rice husk or straw. Here, the alkalinity refers to an alkali component (carbonic acid: H ₂ CO ₃ , carbonate ion: CO ₃ ²⁻ , hydrogen carbonate ion: HCO ₃ ⁻ , hydroxide ion: OH ^−, etc.) contained in water as calcium carbonate. It is the value converted into (CaCO ₃ ).

  Furthermore, in the present invention, it is desirable to add slaked lime having an alkalinity of about 65% as the calcium hydroxide source at a ratio of about 10% by weight with respect to rice husk or straw.

  Moreover, in this invention, it is preferable to hold | maintain the pressure in the said processing container to 1.45 Mpa or more.

  According to the present invention, the rice husk or cocoon is subjected to property conversion treatment in a short time and at a low cost without generating harmful substances from the husk or cocoon, and the rice husk or cocoon that has been difficult to reuse is conventionally used as a moisture adjusting material. It can be used as a useful material such as snow melting material.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a modified material for rice husks and the like and a method for producing a modified material for rice husks according to the present invention will be described with reference to the drawings.

  The modified material such as rice husk of the present embodiment is produced by treating rice husk or rice husk with a calcium hydroxide source mixed in the rice husk or rice husk and treating with a predetermined high-pressure steam. As the calcium hydroxide source, slaked lime which is calcium hydroxide may be mixed, or scallop shell pulverized material may be mixed. The required mixing amount of the calcium hydroxide source varies depending on the alkalinity, but if the alkalinity is about 65 to 80%, about 6 to 10% by weight may be mixed with the rice husk or straw. The treatment conditions with high-pressure steam need to be maintained at a pressure that can be changed to a soft property such as cotton without burning rice husks or soot, and it is sufficient to maintain the pressure at about 1.45 MPa or more. If the pressure is maintained at 65 MPa or more, the treatment can be performed in about 5 to 30 minutes.

  Next, a system 1 for producing a modified material such as rice husk of the present embodiment will be described with reference to a schematic diagram shown in FIG. This modified material production system 1 for rice husks and the like includes a processing vessel 2 for containing and processing rice husks or straws, and a stirring means 3 for stirring the rice husks or straws and the calcium hydroxide source charged in the processing vessel 2. A steam injection means 4 for injecting high-pressure steam into a mixture of rice husk or straw and a calcium hydroxide source in the processing container 2, and a pressure adjusting means 5 for adjusting the pressure in the processing container 2. The control means 6 controls the stirring means 3, the water vapor injection means 4 and the pressure adjusting means 5.

  The constituent parts of the rice husk and other modified material manufacturing system 1 will be described in more detail. The processing vessel 2 is constituted by a first-type pressure vessel having pressure resistance, and the upper portion is filled with rice husk or straw. A port 21 is provided, and a discharge port 22 is provided in the lower part. 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. Further, the processing container 2 is provided with an upper temperature sensor 23a, a lower temperature sensor 23b, and a pressure sensor 24, and the temperature and pressure in the processing container 2 are detected.

  The stirring means 3 includes a horizontal rotation shaft 31 that is horizontally supported in the processing container 2 and a stirring blade 32 that is attached to the horizontal rotation shaft 31 so as to be inclined forward. A drive motor 33 that rotates forward and backward is connected to the horizontal rotation shaft 31. The stirring blade 32 is arranged over the entire horizontal rotating shaft 31 for mixing, stirring and transferring the rice husk or straw and the calcium hydroxide source. Further, the drive motor 33 can control the rotation speed and rotation direction by inverter control, and can reciprocate the rice husk or the mixture of rice husk and calcium hydroxide source in the processing vessel 2 as necessary.

  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 to apply high-pressure steam when the mixture of rice husk or cocoon and the calcium hydroxide source in the processing vessel 2 is stirred and floated in the air, and processing unevenness occurs in the deposited rice husk or cocoon. It is to prevent. Thereby, high processing efficiency is 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 the rotation speed of the drive motor 33 to control the time for stirring and transferring the rice husk or straw in the processing container 2. Moreover, in order to process rice husks or cocoons, the pressure in the processing container 2 is maintained at 1.45 MPa to 1.96 MPa based on 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

  Next, a method for producing a modified material such as rice husks in this embodiment using the modified material production system 1 such as rice husk will be described.

  First, rice husks or straws and a calcium hydroxide source are charged into the processing container 2 from the charging port 21. At this time, if the alkalinity of the calcium hydroxide source is 65 to 80%, the calcium hydroxide source is mixed at a ratio of 6 to 10% by weight with respect to the rice husk or straw to be added. This means that if the alkalinity is lower than 65% or the mixing amount is less than 6% by weight, the modified material such as rice husk after the treatment may show acidity. This is because it is necessary to adjust.

  On the other hand, if the alkalinity is high, the amount of mixing can be reduced, so that for example, 10% by weight of the calcium hydroxide source is sufficient. If the calcium hydroxide source is mixed excessively, it causes a failure of the processing apparatus and is wasteful in terms of cost.

  It is also affected by the humidity where the rice husks or straws were stored. For example, when stored indoors, it is relatively dry and has a moisture content compared to that stored outdoors. Because of its small size, it exhibits the desired properties with a smaller amount (about 6% by weight) of calcium hydroxide source. Therefore, it is preferable to appropriately adjust the amount and alkalinity of the calcium hydroxide source to be mixed according to the amount of rice husk or straw to be treated and the moisture content.

  In addition, the control unit 6 is set in advance so that the pressure in the processing container 2 is 1.45 MPa or more, and the time for holding the set pressure, the stirring time, and the temperature in the container corresponding to the set pressure are set. Keep it. In this case, the pressure holding time is preferably set to a time when the rice husk or cocoon starts hydrolysis, and the stirring time is preferably set to a time at which the properties of the rice husk or cocoon can be suitably changed. Further, the temperature in the container is set to a temperature associated with the theoretical pressure of water vapor.

  The rice husk or straw and the calcium hydroxide source charged into the processing container 2 are gradually transferred toward the outlet 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 husk or straw and the calcium hydroxide source are scattered apart above the horizontal rotation shaft 31 by the stirring of the stirring means 3, high-pressure steam is effectively sprayed. Therefore, the heating accompanying the water vapor pressure and the hydrolysis of the water vapor proceed effectively.

  Further, while the rice husk or straw and the calcium hydroxide source are being stirred, the control means 6 maintains the set temperature of the temperature in the processing container 2 based on the detection results of the temperature sensors 23a and 23b and the pressure sensor 24. At the same time, the water vapor injection means 4 and the pressure adjustment means 5 are controlled so that the pressure is maintained at 1.45 MPa or more.

  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 so that the high pressure water vapor is exhausted from the exhaust pipe. The inside of the processing container 2 is depressurized by exhausting to 52.

  By the above treatment, the rice husk or cocoon is separated and decomposed by the binding molecules, and further, a material that is soft and changed into a fiber like cotton can be obtained by the action of the calcium hydroxide source. In addition, harmful substances and odors contained in rice husk or straw are almost eliminated and water absorption is improved.

  Next, specific examples of the present embodiment will be described. In this example, slaked lime having an alkalinity of 65% was mixed with 25 kg (10% by weight) of 250 kg of rice husk. The processing vessel 2 has a capacity of 3000 liters, and the pressure in the processing vessel 2 is 1.45 MPa to 1. .5 which is appropriate according to the above-mentioned patent application of the present inventor (Japanese Patent Application No. 2003-302971). 96 MPa, particularly 1.65 to 1.85 MPa is preferable in consideration of processing time and cost. Therefore, in this example, the processing was performed at 1.85 MPa. In the present embodiment, the maximum pressure is set to 1.96 MPa, but the same effect can be obtained even with a pressure value higher than that and the processing speed can be further shortened.

  Further, the container temperature was maintained around 200 ° C., which is a temperature associated with the theoretical pressure of water vapor, and rice husk and slaked lime were filled so that the filling rate was 65% to 95%. Further, in order to stir the rice husk and slaked lime uniformly, the stirring speed is set to 2 to 18 rpm until the value of the lower temperature sensor 23b matches the value of the upper temperature sensor 23a, and the pressure is reduced to 0.15 MPa from the time of matching. Up to 5-15 rpm. On the other hand, as a comparative example with respect to the present example, the slaked lime was not mixed, and the treatment was performed under the same conditions using only rice husk. The processing results of these examples and comparative examples are shown in FIG. Moreover, the digital photograph image which image | photographed the shape before the process of a chaff was shown in FIG. 3, the chaff state after the process by a present Example is shown in FIG. 4, and the chaff state after the process by a comparative example is shown in FIG.

  As a result of this example, both the example and the comparative example were completed in a short time of about 5 to 10 minutes. On the other hand, when comparing the properties, the rice husk treated without mixing slaked lime in the comparative example was a fine powder and hard like sand, but the rice husk treated by mixing slaked lime according to this example was It became soft like cotton and changed to completely different properties.

  In the case of the treatment according to the comparative example, the water absorption was low in the case of the treatment according to the comparative example. However, in the case of the treatment according to the present example, the water absorption rate was considerably high, and properties suitable for the moisture adjusting material were recognized. As for the pH value, in the case of the treatment according to the comparative example, acidity of pH 4.3 was shown and an acetic acid-based odor was generated, whereas in the case of the treatment according to this example, the pH value was 7.02. It shows the nature and has almost no odor, and it is extremely easy to handle as a moisture adjusting material or compost.

  Furthermore, the moisture content of the rice husk before the treatment was 19% and the retained heat amount was 11.24 kJ, but the moisture content of the rice husk after the treatment according to this example was 11% and the retained heat amount was 12.15 kJ. there were. Normally, the moisture content in the air increases due to the passage of time, and the moisture content increases. However, the rice husk after the treatment according to this example retains a low moisture content even after the lapse of 24 hours. It can be said that it is highly practical as a material. In addition, since it retains a high amount of heat it can be used as a fuel resource.

  The experiment was conducted by changing the amount of slaked lime with reference to the above example. As long as the rice husk was dried according to storage conditions such as indoor storage, the amount of slaked lime was about 15 kg with respect to 250 kg of rice husk. Results close to those of the examples are obtained. Moreover, if the alkalinity of slaked lime is high, for example, if the alkalinity is about 80%, a result close to the present example can be obtained even with 18 kg of slaked lime with respect to 250 kg of rice husk.

  As mentioned above, the processing conditions for converting rice husk into a useful property as a moisture adjusting material are slaked lime having an alkalinity of 65 to 80%, a ratio of 6% by weight or more, preferably 6 to 10% by weight with respect to rice husk. More preferably, slaked lime having an alkalinity of about 65% is added at a ratio of about 10% by weight to the rice husk. Moreover, it is preferable to hold | maintain the pressure in the processing container 2 at 1.45 MPa or more for 5 minutes-90 minutes, More preferably, it is preferable to hold | maintain at 1.65-1.85 MPa for 5 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 moisture and water vapor contained in the rice husk are cooled, and the condensed moisture is diffused out of the container with a change in state from pressure to no pressure, adjusted to an appropriate moisture content, The properties are converted as follows.

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

  For example, in the above-described embodiment, the material is converted into a property useful as a moisture adjusting material, but the modified material such as rice husk after the processing has properties suitable for a snow melting material, a soil improvement material, a fertilizer, and the like. .

It is a mimetic diagram showing one embodiment of a system which manufactures modification materials, such as a rice husk concerning the present invention. It is a table | surface which shows the process result of the Example in this embodiment, and a comparative example. It is a digital photograph image which shows the chaff before processing in a present Example. It is a digital photograph image which shows the chaff after processing by a present Example. It is a digital photograph image which shows the chaff after processing by a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Modified material production system, such as rice husk 2 Processing container 3 Stirring means 4 Steam injection means 5 Pressure adjusting means 6 Control means 7 Silencer 8 Cooling device 9 Waste water treatment equipment 21 Input port 22 Outlet port 23a Upper temperature sensor 23b Lower temperature sensor 24 Pressure sensor 31 Horizontal rotation shaft 32 Stirrer blade 33 Drive motor 41 Boiler 42 Air supply pipe 51 Pressure adjustment valve 52 Exhaust pipe

Claims (6)

  A modified material for rice husks or the like, wherein the rice husk or cocoon is mixed with a calcium hydroxide source and treated under a predetermined water vapor pressure that does not burn the rice husk or cocoon.   The modified material for rice husks or the like according to claim 1, wherein the rice husks or cocoons are treated under a water vapor pressure of 1.45 MPa or more.   A rice husk or cocoon and a calcium hydroxide source are mixed in the processing container, and a predetermined pressure of water vapor is injected into the processing container to increase the internal pressure and temperature, and the husk or cocoon is maintained at a water vapor pressure at which the rice husk or cocoon does not burn. And a method for producing a modified material such as rice husk.   4. The method for producing a modified material for rice husks or the like according to claim 3, wherein the calcium hydroxide source is added at a ratio of 6% by weight or more with respect to rice husk or rice husk when the alkalinity is 65 to 80%. .   5. The method for producing a modified material such as rice husk according to claim 4, wherein slaked lime having an alkalinity of about 65% is added as the calcium hydroxide source at a ratio of about 10% by weight to rice husk or rice husk. 6. The method for producing a modified material such as rice husk according to claim 3, wherein the pressure in the processing container is maintained at 1.45 MPa or more.