JP2009067882A - Classification method and reutilization method of catalyst particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decomposition method of organic substances, decomposing the organic substances to be a gas by bringing the organic substances into contact with catalyst particles, wherein the catalyst particles of the decomposition residue is separated from the inorganic substances, and the recovered catalyst particles are reused for the decomposition of the organic substances. <P>SOLUTION: The classification method comprising a crushing step (S101) for crushing a mixture of the organic substances and the inorganic substances, a first separating step (S102) for separating into a large diameter mixture having a larger particle diameter than the predetermined valuer and a small diameter mixture having a particle diameter less than the predetermined valuer, based on the each crushed mixture particle diameter represented by the maximum diameter thereof, a decomposition step (S103) for introducing the large diameter mixture into a decomposition device filled with the catalyst particles, bringing the organic substances in the large diameter mixture into contact with the catalyst particles to decompose to be the gas and to make the inorganic substances and the catalyst particles to be the decomposition residue, and a second separating step (S104) for separating the decomposition residue remaining in the decomposition device into the inorganic substances and the catalyst particles. The separated catalyst particles are recovered and reused as the catalyst particles for decomposing organic substances. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for decomposing an organic substance using a catalyst to separate an organic substance from an inorganic substance and a method for reusing catalyst particles in a decomposition process for a product.

  In recent years, various recycling efforts have been made to tackle environmental problems, but recycling of organic materials such as plastics is extremely difficult, and most of them are currently disposed of in landfills or incineration. It has been broken.

  As an example of the incineration treatment currently used, a treatment method using a kiln type gasification furnace can be cited. In the kiln type gasification furnace, waste is indirectly heated to thermally decompose organic matter in the waste, and divided into pyrolysis gas and pyrolysis residue. In many incineration facilities, generated pyrolysis gas and pyrolysis residue are used as fuel for power generation by a gas turbine and indirect heating of waste.

  However, landfill sites are becoming scarce for landfill disposal, and the incineration process has problems such as the risk of generating toxic gases and dioxins.

  On the other hand, as a method for treating an organic substance that can suppress the generation of toxic gas and dioxin, a method is proposed in which the organic substance is brought into contact with heated titanium oxide particles and can be easily decomposed at a low temperature (for example, Patent Documents 1 and 2). ).

  FIG. 9 is a perspective view showing a part of the organic substance decomposition apparatus used in the organic substance decomposition method described in Patent Document 1, and FIG. 10 shows an organic substance decomposition method using the organic substance decomposition apparatus shown in FIG. It is a flowchart for demonstrating.

  The decomposition apparatus 1 shown in FIG. 9 has an air introduction apparatus 2, an organic substance introduction unit 3, and a heating apparatus 4, and titanium oxide particles 5 are filled in the lower part of the decomposition apparatus 1. Has been heated.

  Then, as shown in FIG. 10, when an organic substance is introduced into the decomposition apparatus 1 from the organic substance introduction unit 3 in the decomposition step (S1001) and stirred with the titanium oxide particles 5 at a predetermined temperature, the organic substance is titanium oxide. It is decomposed by the catalytic effect of the particles 5 to become gas (decomposed gas). In this example, since stirring is performed by air ejected from the air introduction device 2, no special stirring device is provided.

The gas generated by the decomposition of the organic matter and the air remaining without being used for the decomposition of the organic matter are discharged from the discharge port 6 together with a part of the titanium oxide particles 5. In order to supplement the titanium oxide particles 5 discharged from the discharge port 6, the decomposition apparatus 1 is provided with a supply tool 7 for supplying the titanium oxide particles 5.
JP-A-2005-48160 JP 2005-169293 A

  However, usually, organic substances are rarely discharged as waste alone, and are almost always discharged as a mixture with inorganic substances such as metals. However, there is a problem that the amount of inorganic substances accumulated in the decomposition apparatus 1 increases and the decomposition efficiency of organic substances decreases.

  FIG. 11 is a flowchart for explaining the waste treatment using the organic matter decomposing apparatus shown in FIG. 9. In the decomposition step (S1101), after the decomposition process similar to the flow shown in FIG. 10 is performed. The catalyst (titanium oxide particles) that has finally been decomposed of the organic substance is mixed with an inorganic substance as a decomposition residue. In order to reuse this catalyst for the decomposition of the organic substance again, the catalyst particles and the inorganic substance are separated from the decomposition residue. Need to be separated.

  However, it is difficult to separate and recover all inorganic substances using existing technologies such as sieve sorting and magnetic sorting alone, and as a result, they cannot be reused for decomposition of organic substances, and both catalyst particles and inorganic substances are discarded. The disposal was done.

  The present invention solves the above-mentioned problems in the prior art, and separates the catalyst particles that have become decomposition residues from the inorganic substances, and enables the recovered catalyst particles to be reused for the decomposition of organic substances, It is another object of the present invention to provide a method for recycling catalyst particles.

  In order to achieve the above object, the separation method according to the present invention includes a crushing step of crushing a mixture composed of an organic substance and an inorganic substance, and selecting the particle size of the crushed mixture in two large and small groups by comparing with a predetermined value. And a separation step of bringing the catalyst particles into contact with the selected mixture of large groups and taking out the inorganic substances.

  In the above method, the first sorting step is intended to remove those that are difficult to sort with the catalyst particles, and those that are introduced into the decomposition apparatus are classified into inorganic substances and organic substances that are easy to sort with the catalyst particles. By limiting, it is possible to selectively collect catalyst particles and inorganic substances from the decomposition residue.

  In the fractionation method according to the present invention, it is preferable that the particle size of the crushed mixture indicates the maximum dimension of each of the crushed mixtures.

  Preferably, the separation step of bringing the catalyst particles into contact with the selected mixture having a large particle size and taking out the inorganic substance decomposes by bringing the catalyst particles into contact with the organic matter in the large particle mixture having a large particle size, The method includes a decomposition step in which a mixture of the inorganic substance and the catalyst particles in the large particle mixture is used as a decomposition residue, and a second selection step in which the decomposition residue is selected into the inorganic substance and the catalyst particles.

  Preferably, the catalyst particles selected by the second selection step are taken out.

  Preferably, both the first sorting step and the second sorting step are sieve sorting.

  Preferably, the sieve used in the first sorting step and the second sorting step is a sieve having a mesh with an equal diameter.

  Preferably, the first selection step has a mesh larger than d + 3σ, where d is the average particle diameter of the catalyst particles before the decomposition of the organic matter and the standard deviation of the particle size distribution is σ. Desirably, the second sorting step is a sieve sorting having a mesh larger than d + 3σ and not larger than the mesh size of the first sorting step.

  Preferably, the catalyst particles are titanium oxide particles.

  The method for reusing catalyst particles according to the present invention is characterized in that the catalyst particles taken out by the fractionation method according to the present invention are used for fractionation of another mixture.

  As described above, according to the present invention, the mixture of organic and inorganic substances in the waste is pulverized, and the mixture having a particle size larger than the predetermined value is selected and introduced into the decomposition apparatus in the first selection step. Thus, it becomes possible to easily select the catalyst particles that have become decomposition residues and the inorganic substances in the mixture. Therefore, the catalyst particles can be easily selected and recovered, and can be reused.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a flowchart relating to a fractionation method and a catalyst reuse method which are preferred embodiments of the present invention.

  First, waste such as waste home appliances consisting of a mixture of organic materials such as plastic and inorganic materials such as metals is crushed in the dismantling, crushing and sorting step (S101), wind sorting, specific gravity sorting, magnetic sorting, and Using a sorting technique such as eddy current sorting, a portion of the inorganic material such as iron, aluminum, and copper is recovered from the waste. Most of the inorganic substances collected here are metals, and material recycling is performed.

  On the other hand, the remaining waste is an organic waste mainly composed of organic matter, and this includes inorganic matter that could not be recovered in the dismantling / crushing / sorting step (S101). .

  Next, the organic waste is passed through a first sorting step (S102). The first sorting step S102 is composed of a sieve having a 4 mm square mesh, which will be described later. When the maximum diameter of each particle of organic waste is the particle diameter of the particle, the particle diameter is on the sieve. Large organic waste (large particle size mixture) larger than 4 mm remains, and small organic waste (small particle size mixture) having a particle size of 4 mm or less mainly falls under the sieve.

  Here, both large organic waste and small organic waste contain inorganic substances, but it is difficult to recover inorganic substances from small organic wastes. And only the large organic waste is passed through the next decomposition step (S103).

  The decomposition step (S103) includes a decomposition device having a heating device, an air introduction device, and a stirring device, and the decomposition device is filled with titanium oxide catalyst particles having a particle size of 4 mm or less. It is heated to a temperature of

  The large organic waste that has passed through this decomposition step (S103) is uniformly stirred by the stirring device together with the titanium oxide catalyst particles heated in the decomposition device and the air introduced from the air introducing device. Organic matter such as plastic in the waste is decomposed into a gas and released as a decomposition gas.

  On the other hand, the inorganic substance contained in the large organic waste remains in the decomposition apparatus as a decomposition residue together with the titanium oxide catalyst particles.

  In the present embodiment, only air is introduced from the air introduction device, but a gas having a larger proportion of oxygen necessary for decomposition of the resin may be used, or oxygen gas may be used as it is.

  Next, the decomposition residue remaining in the decomposition apparatus is collected and passed to the second sorting step (S104).

  The decomposition residue is composed of an inorganic substance contained in a large organic waste having a particle size larger than 4 mm and titanium oxide catalyst particles having a particle size of 4 mm or less. The second sorting step (S104) Like the sorting step (S102), it is composed of a sieve with a 4mm square mesh, so the inorganic substances contained in the large organic waste remain on the sieve, and below the sieve are titanium oxide catalyst particles. Falls.

  Here, the inorganic substance remaining on the sieve is collected and recycled.

  Further, the titanium oxide catalyst particles dropped under the sieve are collected and returned to the decomposition apparatus in the decomposition step (S103), and reused again as the decomposition catalyst.

  In this embodiment, a sieve having a 4 mm square mesh is used in the first sorting step (S102) and the second sorting step (S104), but in the first sorting step (S102), the size of the mesh is used. If the average particle diameter of the titanium oxide catalyst particles packed in the decomposition apparatus is d and the standard deviation of the particle size distribution is σ, a sieve having a mesh of any size can be used as long as it is larger than d + 3σ. Well, in the second sorting step (S104), the size of the sieve having any mesh size is similarly larger than d + 3σ and smaller than the size of the mesh of the sieve used in the first sorting step (S102). But you can. Here, d + 3σ represents the maximum value of the particle diameter of the titanium oxide catalyst particles.

  However, in the first sorting step (S102), the larger the mesh size of the sieve, the larger the amount of small organic waste that falls under the sieve and is disposed of, and the maximum particle size of the titanium oxide catalyst particles. It is not recommended to use a sieve with a mesh whose size is far from the value.

  Moreover, in this embodiment, although the decomposition | disassembly process (S103) is performed by batch processing, you may perform continuously to a 2nd selection process (S104) and collection | recovery and reuse of a titanium oxide catalyst particle.

  Next, the sorting method of the present invention will be described more specifically with reference to the recycling of the washing machine shown in FIG.

  FIG. 2 is a flowchart relating to the recycling process of the washing machine according to the embodiment of the present invention.

  First, in the dismantling step (S201), the drainage hose attached to the outside of the washing machine and a concrete weight such as a weight that adversely affects crushing are removed, and the remaining washing machine body is pressed in the pressing step (S202), Remove salt water, etc., provided as a balancer in the washing tub.

  Next, in the crushing / sorting step (S203), the pressed washing machine body is crushed and separated into large metals and mixed waste through various sorters such as a specific gravity sorter and a magnetic sorter. Collect and recycle.

  The mixed waste includes organic substances such as PP (polypropylene), PS (polystyrene), rubber, and non-woven fabric, as well as metals such as copper wires and harnesses.

  Next, the mixed waste is passed through the water specific gravity sorting step (S204), and sorted into three types of light specific gravity mixture, medium specific gravity mixture, and heavy specific gravity mixture using the specific gravity difference.

  The light specific gravity mixture of this example composed of PP is recovered and recycled.

  The material composition ratio of the medium specific gravity mixture in this example is shown in FIG. 3, and the material composition ratio of the heavy specific gravity mixture is shown in FIG.

  The medium specific gravity mixture is mostly composed of PP and PS and does not contain metal, whereas the heavy specific gravity mixture is almost composed of metal such as copper wire and harness.

  Therefore, the heavy specific gravity mixture is passed through the first sorting step (S205).

  The first sorting step (S205) includes a special sieve having a four-layer structure shown in FIGS. FIG. 5 is a perspective view of a sieve used in the first sorting step, and FIG. 6 is a front view of the sieve shown in FIG.

  5 and 6, the first sieve layer 9, the second sieve layer 10, the third sieve layer 11, and the fourth sieve layer 12 are arranged in order from the top on the sieve 8, and the gap between the layers is 4 mm. They are separated one by one. Moreover, the 1st sieve layer 9-the 4th sieve layer 12 are all comprised with the sieve which has a 4 mm square mesh, and are arrange | positioned so that the position of each mesh may differ.

  The top views of the first sieve layer 9 to the fourth sieve layer 12 are shown in FIGS. The first sieve layer 9 has the structure shown in FIG. 7A, the second sieve layer 10 has the structure shown in FIG. 7B, the third sieve layer 11 has the structure shown in FIG. 7C, and the fourth sieve layer 12 Each has a structure shown in FIG.

  Therefore, the planar state of the sieve 8 in which only the first sieve layer 9 and the second sieve layer 10 are arranged is as shown in FIG. 8A, and when the third sieve layer 11 is additionally arranged, FIG. When the fourth sieve layer 12 is finally arranged as shown in FIG. 8C, the result is as shown in FIG.

  The specific gravity mixture passed through the first sorting step (S205) is classified into a large particle size specific gravity mixture having a particle size larger than 4 mm and a small particle size specific gravity mixture having a particle size of 4 mm or less. Since it is difficult to further sort the mixture of specific gravity and specific gravity, it is disposed of.

  Here, in the first sorting step (S205), by using a special four-layered sieve such as the sieve 8, the copper wires and harnesses occupying most of the metal contained in the heavy specific gravity mixture are made of the sieve. It can be prevented from being discarded with the small particle size specific gravity mixture that remains on top and falls under the sieve.

  The collected large particle size specific gravity mixture is passed to the drying step (S206) together with the medium specific gravity mixture separately collected in the water specific gravity selection step (S204), and the contained water is evaporated.

  Since the heavy specific gravity mixture and the medium specific gravity mixture pass through the water specific gravity sorting step (S204) and contain a large amount of moisture, there is a possibility that the decomposition will be adversely affected in the subsequent decomposition step (S207). Since it is preferable to remove in advance, a drying step (S206) is provided before the decomposition step (S207).

  However, if sufficient energy can be applied in the decomposition step (S207), the drying step (S206) may not be passed.

  In this example, the medium specific gravity mixture and the large particle size specific gravity mixture are passed through the same drying step (S206), but may be passed through different drying steps. In addition, after passing the heavy specific gravity mixture through the first sorting step (S205), it passes through the drying step (S206), but after passing through the drying step (S206), it passes through the first sorting step (S205). Good. However, by arranging the drying step (S206) immediately before the decomposition step (S207), the heat of drying can also be used as preheating for decomposition, so the arrangement of this embodiment is more desirable.

  Next, the medium specific gravity mixture and the large particle size specific gravity mixture that have passed through the drying step (S206) are passed to the decomposition step (S207).

  The decomposition step (S207) includes a decomposition device having a heating device, an air introduction device, and a stirring device, and the decomposition device is filled with titanium oxide catalyst particles having a particle size of 4 mm or less. It is heated to around ℃.

  The medium specific gravity mixture and large particle specific gravity mixture passed through the decomposition step (S207) are uniformly stirred by the stirring device together with the titanium oxide catalyst particles heated in the decomposition device and the air introduced from the air introducing device. The organic matter in the medium specific gravity mixture and the large particle size specific gravity mixture is decomposed into a gas and released as a decomposition gas.

  On the other hand, the inorganic substance contained in the large particle size specific gravity mixture remains in the decomposition apparatus as a decomposition residue together with the titanium oxide catalyst particles.

  In the present embodiment, only air is introduced from the air introduction device, but a gas with an increased ratio of oxygen necessary for the decomposition of the resin may be used, or oxygen gas may be used as it is.

  Next, the decomposition residue remaining in the decomposition apparatus is collected and passed to the second sorting step (S208).

  The decomposition residue is composed of an inorganic substance contained in a large particle size specific gravity mixture having a particle size larger than 4 mm, and titanium oxide catalyst particles having a particle size of 4 mm or less. In the second sorting step (S208), Because it is composed of a sieve having the same structure as the sieve 8 used in the first sorting step (S205), the inorganic substances contained in the large particle size specific gravity mixture remain on the sieve, and below the sieve Titanium oxide catalyst particles fall.

  Here, the inorganic substance remaining on the sieve is collected and recycled. Further, the titanium oxide catalyst particles dropped under the sieve are recovered and returned to the decomposition apparatus in the decomposition step (S207), and reused again as a decomposition catalyst.

  In this embodiment, the first sorting step (S205) and the second sorting step (S208) use a four-layer sieve 8 in which four sieves having a 4 mm square mesh are arranged at intervals of 4 mm. However, in the first sorting step (S205), the mesh size is expressed as follows: d + 3σ, where d is the average particle diameter of the titanium oxide catalyst particles packed in the decomposition apparatus, and d is the standard deviation of the particle size distribution. Can be combined with sieves having any mesh size, and sieves with different mesh sizes can be combined. If the interval between the sieve layers is larger than d + 3σ, a wider interval can be used. May be opened.

  Also, in the second sorting step (S208), any size can be used as long as the mesh size is larger than the above d + 3σ and is not more than the minimum value of the mesh size of the sieve used in the first sorting step (S205). Sieves having different mesh sizes may be combined, sieves having different mesh sizes may be combined, and the intervals between the sieve layers are larger than d + 3σ, and the sieve layers arranged in the first sorting step (S205) As long as it is less than or equal to the minimum value of the interval, any interval may be provided.

  However, in the first sorting step (S205), the larger the mesh size of the sieve, the larger the amount of the small particle size specific gravity mixture that falls under the sieve and is disposed of, so that there is too much space between each sieve layer. Since metals such as copper wires and harnesses contained in the heavy specific gravity mixture easily fall under the screen, the amount discarded as a small particle heavy specific gravity mixture increases, so it is not recommended.

  In this embodiment, the decomposition step (S207) is performed by batch processing, but the second selection step (S208) and the recovery and reuse of the titanium oxide catalyst particles may be performed continuously.

  The separation method of the present invention is applied to the separation of organic materials and inorganic materials of various waste products, and in particular, in the recycling process of electrical and electronic equipment, processing of waste plastic mixed with metal and mounting of metal parts. This is useful as a method for reusing catalyst particles when a printed circuit board is processed.

The flowchart which concerns on the fractionation method which is a suitable embodiment of this invention, and the reuse method of a catalyst The flowchart which concerns on the recycling process of the washing machine which is an Example of this invention The figure which shows the raw material composition ratio of the medium specific gravity mixture used in the present Example. The figure which shows the raw material composition ratio of the heavy specific gravity mixture used in the present Example. The perspective view which shows the whole sieve in a present Example Front view of sieve in this example (A)-(d) is a top view of each sieve layer which comprises the sieve in a present Example. (A)-(c) is a top view which shows each sieve layer and arrangement | positioning structure in a present Example The perspective view which shows the decomposition apparatus currently used with the conventional organic substance decomposition | disassembly method partially fractured | ruptured FIG. 9 is a flowchart when only organic substances are processed by the organic substance decomposition method using the apparatus shown in FIG. Flow chart when waste is processed by the organic matter decomposition method using the apparatus shown in FIG.

Explanation of symbols

8 Sieve 9 1st Sieve Layer 10 2nd Sieve Layer 11 3rd Sieve Layer 12 4th Sieve Layer S101 Dismantling / Crushing / Sorting Step S102 First Sorting Step S103 Decomposing Step S104 Second Sorting Step S201 Dismantling Step S202 Pressing Step S203 Crushing Sorting step S204 Water specific gravity sorting step S205 First sorting step S206 Drying step S207 Decomposing step S208 Second sorting step

Claims (9)

A crushing step of crushing a mixture of organic and inorganic materials,
A first sorting step in which the particle size of the crushed mixture is compared with a predetermined value and divided into two large and small groups;
A separation step of bringing the catalyst particles into contact with the selected mixture of large groups and taking out inorganic substances.   The method according to claim 1, wherein the particle size of the crushed mixture indicates the maximum dimension of each of the crushed mixtures. The separation step of bringing the catalyst particles into contact with the selected mixture having a large particle size and taking out the inorganic material is decomposed by bringing the catalyst particles into contact with the organic material in the large particle mixture having a large particle size, and the inorganic material in the large particle mixture is decomposed. And a decomposition step using a mixture of the catalyst particles as a decomposition residue;
The separation method according to claim 1, further comprising a second sorting step of sorting the decomposition residue into the inorganic substance and the catalyst particles.   The separation method according to claim 3, wherein the catalyst particles selected in the second selection step are taken out.   The sorting method according to claim 1, 3 or 4, wherein the first sorting step and the second sorting step are both sieve sorting.   The classification method according to any one of claims 1 to 3, wherein the sieve used in the first sorting step and the second sorting step is a sieve having a mesh with an equal diameter.   When the average particle diameter of the catalyst particles before the decomposition of the organic substance is d and the standard deviation of the particle size distribution is σ, the first selection step is sieve selection having a mesh larger than d + 3σ, 7. The screen according to claim 1, wherein the second sorting step is a sieve sorting having a mesh larger than d + 3σ and having a mesh size equal to or smaller than the mesh size of the sieve of the first sorting step. Sorting method.   The separation method according to claim 1, 3, 4, or 7, wherein the catalyst particles are titanium oxide particles.   A method for reusing catalyst particles, wherein the catalyst particles taken out by the fractionation method according to claim 3 or 4 are used for fractionation of another mixture.

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