JP2011072948A - Waste treatment method and waste treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste treatment method and a waste treatment apparatus, which can suppress a remaining of a water-soluble chemical substance in a treated material after an organic waste containing the water-soluble chemical substance is treated. <P>SOLUTION: The waste treatment method includes contacting the organic waste having the water-soluble chemical substance with saturated steam of 150°C or higher in a sealed reactor to decompose the organic waste. While condensate water formed by a condensation of the saturated steam on the surface of the organic waste is separated from the organic waste, the organic waste is decomposed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a waste treatment method and a waste treatment apparatus for treating organic waste with water vapor.

  In recent years, from the viewpoint of environmental protection and effective use of resources, attempts have been made to treat waste (industrial waste, general waste, etc.) by an appropriate method, and use the obtained treatment for various purposes. Yes. For example, organic waste consisting of garbage, food residues, livestock manure, etc. is decomposed by contacting with high-temperature saturated steam, and then the decomposed organic waste is heated and dried to adhere to saturated steam Attempts have been made to evaporate the condensed water and use the dried processed product as fuel (see Patent Document 1).

  According to the treatment method as described above, the organic waste is heated and hydrolyzed by high-temperature saturated steam in a sealed reaction vessel, so that a finely ground treatment product can be obtained, Since the organic waste is not burned, the organic waste can be made fine without reducing the amount of heat originally held by the organic waste. For this reason, the obtained processed material can be used as a high-quality fuel, for example, it can be used as a fuel for combustion equipment such as a firing furnace or various boilers used when producing cement.

JP 2007-136312 A

  However, in the method as described above, since the water-soluble chemical substance contained in the organic waste is dissolved in the condensed water adhering to the treated product, the water-soluble chemical substance is dissolved by drying the treated product. The chemical substance is concentrated and remains in the processed material at a high concentration.

  When such a processed product is used as a fuel, deterioration of the combustion facility may be accelerated or damaged due to the influence of the remaining chemical substances. In particular, organic waste consisting of food residues and the like contains many chlorine compounds, so in the above method, the chlorine component is concentrated in the treated product and remains at a high concentration. The combustion equipment may be corroded.

  Further, when used as a fuel for a firing furnace, residual chemical substances may be contained in the cement, which may cause a deterioration in the quality of the cement.

  Therefore, the present invention has been made in view of such problems of the prior art, and the water-soluble chemical substance is contained in a treated product after treating an organic waste containing a water-soluble chemical substance. An object of the present invention is to provide a waste treatment method and a waste treatment apparatus that can suppress the remaining of the waste.

  The waste treatment method according to the present invention is a waste treatment method in which an organic waste containing a water-soluble chemical substance is brought into contact with saturated steam at 150 ° C. or higher in a sealed reaction vessel to decompose the organic waste. The method is characterized in that the organic waste is decomposed while separating the condensed water formed by condensation of saturated water vapor on the surface of the organic waste from the organic waste.

  According to the waste treatment method having such a configuration, the organic waste is hydrolyzed and finely divided by the contact between the saturated water vapor at the temperature and the organic waste, and the surface of the organic waste In this, condensed water of saturated water vapor is formed. In such condensed water, water-soluble chemical substances in the organic waste are eluted, so by separating the condensed water from the organic waste, The water-soluble chemical substance can be prevented from remaining in the treated product).

  The waste treatment apparatus according to the present invention is a waste treatment method in which an organic waste containing a water-soluble chemical substance is brought into contact with saturated steam at 150 ° C. or higher in a sealed reaction vessel to decompose the organic waste. In the reaction vessel, a condensed water recovery space for recovering condensed water of saturated water vapor condensed on the surface of the organic waste is formed in a lower region of the organic waste disposed therein. And a waste supporting means for supporting organic waste.

  According to such a configuration, the reaction container includes the waste support means, and the condensed water recovery space is formed in the lower region of the organic waste by the waste support means, so that the condensed water is contained in the condensed water recovery space. Can be recovered by dropping, and the treated product and condensed water can be easily separated. Thereby, a contact with a processed material and condensed water is prevented, and it can suppress that a water-soluble chemical substance remains in a processed material.

  In the waste treatment apparatus according to the present invention, the waste support means includes a placement portion configured to be capable of placing organic waste, and the placement portion communicates with the condensed water recovery space. It is preferable that a through hole is formed.

  According to such a configuration, the waste support means includes the mounting portion on which the organic waste is placed, and the through-hole is formed in the placing portion, so that the organic waste can be reliably seen from below. And the condensed water can be reliably sent to the condensed water recovery space through the through hole. Moreover, since a mounting part exists between the collect | recovered condensed water and a processed material, condensed water and a processed material can be isolate | separated reliably.

  As mentioned above, according to this invention, it can suppress that the said water-soluble chemical substance remains in the processed material after processing the organic waste containing a water-soluble chemical substance.

(A) is a fragmentary sectional view at the time of seeing the waste disposal apparatus concerning this embodiment from the side, (b) is XX sectional drawing of (a). The figure which showed the inside of the pressure vessel at the time of processing organic waste in an Example.

  Hereinafter, an embodiment according to the present invention will be described with reference to FIG.

  The waste treatment apparatus 1 according to this embodiment is used for the treatment of organic waste A. Specifically, the waste treatment apparatus 1 is intended for treating organic waste A composed of raw garbage, food residues, livestock manure, plastic, organic sludge, and the like. Specifically, the waste treatment apparatus 1 decomposes the organic waste A by bringing it into contact with saturated steam under high temperature and high pressure.

  The waste treatment apparatus 1 includes a reaction vessel 2 configured to be able to arrange organic waste A therein, a water vapor supply means 3 for supplying water vapor into the reaction vessel 2, Stirring means 4 for stirring the organic waste A is provided.

  The reaction vessel 2 is configured to be hermetically sealed and configured to be able to maintain a state in which the inside is at a high pressure. Moreover, the reaction container 2 is comprised from the container main body 2a formed in the cylinder shape (this embodiment cylindrical shape), and the obstruction | occlusion lid 2b which obstruct | occludes the edge part of this container main body 2a. In the present embodiment, the container body 2a is configured such that one end is closed and the other end is closed by the closing lid 2b.

  The closing lid 2b is configured to be detachable from the container main body 2a or to be opened and closed. The other end of the container main body 2a is removed by removing the closing lid 2b from the container main body 2a or opening the closing lid 2b. Can be opened. Further, the stirring means 4 is attached to one end of the container body 2a that is closed so as to penetrate the inside and outside of the container body 2a. Moreover, in this embodiment, the reaction container 2 is arrange | positioned so that the axis | shaft of the cylindrical container main body 2a may become substantially horizontal. In the following description, “upper” and “lower” of the reaction vessel 2 mean “upper” and “lower” when the axis is substantially horizontal.

  In addition, the reaction vessel 2 (specifically, the vessel body 2a) discharges the condensed water B in which the saturated water vapor is condensed and the supply unit 2c for supplying the organic waste A to the inside of the reaction vessel 2 to the outside. And a discharge part 2d. The supply part 2c is formed so as to be positioned above the reaction container 2 (specifically, the container body 2a). On the other hand, the discharge part 2d is formed to be positioned below the reaction vessel 2 (specifically, the vessel body 2a).

  The reaction vessel 2 is configured such that a condensed water recovery space 2f for recovering the condensed water B is formed in a lower region of the organic waste A disposed inside. Specifically, the reaction container 2 includes a waste support means 2e that supports the organic waste A so that a condensed water recovery space 2f is formed in a lower region of the organic waste A disposed inside. I have. In the present embodiment, the waste support means 2e includes a mounting portion 2e configured to be capable of mounting the organic waste A, and the mounting portion 2e has a through hole communicating with the condensed water recovery space 2f. Is formed.

  Specifically, the placing portion 2e has a mesh shape in which a plurality of through holes are formed, and is configured so that the organic waste A does not fall out from the through holes. In the present embodiment, the placement portion 2e is formed using a net-like metal material (punching metal). Further, in the present embodiment, the mounting portion 2e is formed such that the punching metal is formed into a planar shape, and the container main body 2a is located below the inside of the reaction vessel 2, specifically, below the stirring means 4. It is arranged with a space between. Thereby, the condensed water collection | recovery space 2f is formed between the container main body 2a and the mounting part 2e. The condensed water recovery space 2 f is formed between one end and the other end of the container body 2 a along the axis of the reaction container 2. The condensed water recovery space 2f is formed so as to communicate with the discharge part 2d.

  The steam supply means 3 is configured to supply steam at a predetermined temperature into the reaction vessel 2 so that the pressure in the reaction vessel 2 becomes a saturated water vapor pressure. The temperature of the saturated water vapor in the reaction vessel 2 is 150 ° C. or higher, preferably 200 to 235 ° C. At this time, the pressure in the reaction vessel 2 (saturated water vapor pressure) is preferably 1.65 to 3.29 MPa (15 to 33 atm).

  The stirring means 4 includes a stirring blade 4a for stirring the organic waste A, and a rotating shaft 4b to which the stirring blade 4a is connected. A plurality of the stirring blades 4a are connected to the rotating shaft 4b. Moreover, the rotating shaft 4b is arrange | positioned so that the reaction container 2 may be penetrated. Specifically, the rotation shaft 4b is arranged along the axis of the reaction vessel 2 (substantially horizontally in the present embodiment) so as to penetrate the closed one end portion of the vessel body 2a. A rotating means 4c for rotating the rotating shaft 4b around its longitudinal direction is attached to one end of the rotating shaft 4b (specifically, the end located outside the reaction vessel 2). Then, by rotating the rotating shaft 4b, the plurality of stirring blades 4a come into contact with the organic waste A to stir the organic waste A, and the organic waste A is uniform with the saturated water vapor in the reaction vessel 2. It is comprised so that it may contact.

  Next, a mechanism in which the waste treatment apparatus 1 decomposes the organic waste A will be described. The organic waste A supplied from the supply unit 2c into the reaction vessel 2 is stirred by the stirring means 4 (specifically, the stirring blade 4a) and comes into contact with saturated water vapor in the reaction vessel 2. The inside of the reaction vessel 2 is filled with saturated steam at the above temperature and is at the pressure, and the organic waste A is hydrolyzed and finely divided by contact with saturated steam. At this time, saturated water vapor condenses and the condensed water B adheres to the organic waste A. Specifically, when the organic waste A is heated by the saturated water vapor, the saturated water vapor is deprived of heat, so that the saturated water vapor condenses and adheres to the organic waste A. In the condensed water B, water-soluble chemical substances (for example, chlorides) are eluted from the finely divided organic waste A.

  The condensed water B in which the chemical substance is dissolved is dropped and recovered through the through hole of the waste support means 2e (punching metal) into the condensed water recovery space 2f. At this time, since the amount of water vapor in the reaction vessel 2 decreases, water vapor is supplied from the water vapor supply means 3 to maintain the pressure in the reaction vessel 2. In this state, vapor-liquid equilibrium is maintained between the saturated water vapor and the condensed water B in the reaction vessel 2. Then, after the organic waste A is sufficiently finely divided, the condensed water B is discharged from the discharge portion 2d, and the finely divided organic waste A is cooled and dried. Thereby, it becomes a processed material with little content of a water-soluble chemical substance.

  As described above, according to the waste treatment apparatus 1 according to the present embodiment, the water-soluble chemical substance remains in the treated product after treating the organic waste A containing the water-soluble chemical substance. Can be suppressed.

  That is, the water-soluble chemical substance in the organic waste A elutes into the condensed water B condensed on the surface of the organic waste A by the contact of the saturated water vapor with the temperature and the organic waste A, and the condensed water By separating and recovering B from the organic waste A, it is possible to suppress the remaining water-soluble chemical substance in the finely divided organic waste A (processed product). Thereby, a processed material can be utilized as a fuel, without performing the process of removing a water-soluble chemical substance.

  Further, by forming the condensed water recovery space 2f, the condensed water B can be dropped and recovered in the condensed water recovery space 2f, and the processed product and the condensed water B can be easily separated. Thereby, a contact with a processed material and the condensed water B is prevented, and it can suppress that a water-soluble chemical substance remains in a processed material.

  In addition, since the through-hole is formed in the mounting portion (waste support means) 2e, the organic waste A can be treated in a state of being reliably supported from below, and the condensed water B is passed through the through-hole. Can be reliably sent to the condensed water recovery space 2f. Moreover, since the mounting part 2e exists between the collect | recovered condensed water B and a processed material, the condensed water B and a processed material can be isolate | separated reliably.

  Examples of the present invention will be described below.

<Processing device>
As shown in FIG. 2, a 200 mL pressure vessel 20 was used as a reaction vessel, and 15 g of water C was introduced therein. In addition, a metal container 20e formed entirely of a 1 mm mesh metal material is disposed inside the pressure container 20 as waste support means. The metal container 20e is configured such that the sample A can be placed at a position away from the water surface of the water C.

<Example 1>
After 3 to 5 g of sample A was collected from the organic waste derived from food and placed on the metal container 20e, the pressure container 20 was sealed. Then, the pressure vessel 20 was placed in an electric furnace, heated up for about 1 hour until the temperature in the pressure vessel 20 reached 150 ° C., and held for 10 minutes. At this time, the inside of the pressure vessel 20 is saturated with water vapor at 150 ° C., and the saturated water vapor pressure is 0.49 MPa (about 4.8 atm).

  Thereafter, the pressure vessel 20 was taken out from the electric furnace, immediately after removing water vapor and air-cooled to 100 ° C., sample A was taken out and dried at 105 ° C. to obtain a processed product.

  The treatment by the above method was performed on three samples A, and the content of the water-soluble chemical substance (measurement of chlorine concentration) was measured for the obtained processed product. About a measurement result, it shows in following Table 1 only about a maximum value, a minimum value, and an average value. The chlorine concentration was measured based on the chemical analysis method of JIS R5202 Portland cement (21. Chlorine determination method, 21.2. Potentiometric titration method).

<Example 2>
After collecting 3 to 5 g of sample A from food-derived organic waste different from Example 1 and placing it on the metal container 20e, the pressure container 20 was sealed. Then, the pressure vessel 20 was placed in an electric furnace, heated up for about 1 hour until the temperature in the pressure vessel 20 reached 235 ° C., and held for 10 minutes. At this time, the inside of the pressure vessel 20 is saturated by steam at 235 ° C., and the saturated steam pressure is 3.04 MPa (about 30 atm).

  Thereafter, the pressure vessel 20 was taken out from the electric furnace, immediately after removing water vapor and air-cooled to 100 ° C., sample A was taken out and dried at 105 ° C. to obtain a processed product.

  The treatment by the above method was performed on five samples A, and the content of the water-soluble chemical substance (measurement of chlorine concentration) was measured in the same manner as in Example 1 for the obtained processed product. The measurement results are shown in Table 1 below.

<Comparative Example 1>
Two 3 to 5 g samples were collected from the same organic waste as in Example 1, and the content of water-soluble chemical substances was measured under the same conditions as in Example 1 without treatment. The measurement results are shown in Table 1 below.

<Comparative Example 2>
Three 3 to 5 g samples were collected from the same organic waste as in Example 2, and the content of water-soluble chemical substances was measured under the same conditions as in Example 1 without treatment. The measurement results are shown in Table 1 below.

<Summary>
When comparing the example and the comparative example, it is recognized that the chlorine concentration in the example is lower. This is because the chlorine component in the organic waste is eluted in the saturated water vapor condensed water adhering to the surface of the organic waste by treating the organic waste by the above method, and the condensed water becomes the chlorine component. At the same time, it is dropped and recovered below the organic waste through the metal container 20e, so that the condensed water containing chlorine can be separated from the organic waste.
As described above, when treating organic waste with high-temperature saturated steam, the condensed water condensed on the surface of the organic waste is treated while being separated from the organic waste. It is possible to suppress chlorine (water-soluble chemical substance) from remaining in the waste.

  DESCRIPTION OF SYMBOLS 1 ... Waste processing apparatus, 2 ... Reaction container, 2a ... Container main body, 2b ... Closure lid, 2c ... Supply part, 2d ... Discharge part, 2e ... Waste support means, mounting part, 2f ... Condensate recovery space, DESCRIPTION OF SYMBOLS 3 ... Steam supply means, 4 ... Agitation means, 4a ... Agitation blade, 4b ... Rotating shaft, 4c ... Rotation means, 20 ... Pressure vessel, 20e ... Metal container, A ... Organic waste, B ... Condensed water, C ... water

Claims (3)

A waste treatment method for decomposing organic waste by bringing organic waste containing a water-soluble chemical substance into contact with saturated steam at 150 ° C. or higher in a sealed reaction vessel,
A waste treatment method comprising decomposing an organic waste while separating condensed water formed by condensation of saturated water vapor on the surface of the organic waste from the organic waste. A waste treatment apparatus for decomposing organic waste by bringing organic waste containing a water-soluble chemical substance into contact with saturated steam at 150 ° C. or higher in a sealed reaction vessel,
The organic waste is formed so that a condensed water recovery space for recovering condensed water of saturated water vapor condensed on the surface of the organic waste is formed in a lower region of the organic waste disposed therein. A waste treatment apparatus comprising waste support means for supporting the waste.   The waste support means includes a mounting portion configured to be capable of mounting organic waste, and the mounting portion is formed with a through hole communicating with the condensed water recovery space. The waste disposal apparatus according to claim 2.

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