JP2022088272A - Waste treatment system, waste treatment method, and pellets - Google Patents

Abstract

To provide: pellets which are made from organic wastes containing plastics, have a calorific value comparable to coal, hardly contain substances such as chlorine and potassium, but have quality comparable to quality classes according to a total chlorine mass fraction defined for RPF; and a waste treatment system and a waste treatment method that can produce the pellets.SOLUTION: A waste treatment system is provided. The waste treatment system comprises: a subcritical water treatment device to treat organic wastes containing plastics to obtain treated products having lower molecular weight; a gas discharge mechanism to discharge gas components from the subcritical water treatment device; a semi-carbonization device to semi-carbonize pellet ingredients containing the treated products; and a pelletization device to pelletize the pellet ingredients or the semi-carbonized pellet ingredients to obtain pellets.SELECTED DRAWING: Figure 1

Description

The present invention relates to high quality pellets obtained from organic waste containing plastics, a waste treatment system for producing energy (pellets) from the organic waste, and a waste treatment method. In particular, the present invention relates to pellets, which are coal alternative fuels that can be used in a wide variety of fields, waste treatment systems and waste treatment methods capable of producing such pellets.

To date, most of the energy consumed by humankind has been provided by burning fossil fuels. All of these methods release carbon dioxide and combustibles into the environment.

Japan has set a reduction target of 26.0% reduction in greenhouse gas emissions in FY2012 compared to that in FY2013 by reducing domestic greenhouse gas emissions and securing absorption. After that, based on the adoption of the Paris Agreement at COP21, the global warming countermeasure plan was approved by the Cabinet in May 2016.

On the other hand, the Ministry of the Environment announced on January 21, 2016, "Basic policy for comprehensive and systematic promotion of waste reduction and other measures related to proper treatment" based on the Waste Management Law. changed. In this policy, we will set target values from the viewpoint of waste energy utilization, and promote efforts such as effective utilization of waste as an energy source and utilization of waste energy in the region.

However, in small and medium-sized general waste treatment facilities, the current situation is that waste energy is not fully utilized from the viewpoints of not accumulating know-how and high costs. ..

As a method for converting waste into solid fuel, there is a technique for producing solid fuel such as RDF (Refuse Delivered Fuel) and RPF (Refuse Paper & Plastic Fuel) from waste.
RDF is a solid fuel whose main raw material is combustible general waste. The low calorific value is about one-half to two-thirds of that of coal due to the contamination of foreign matter.

On the other hand, RPF is a solid fuel mainly made of used paper and plastic that are separately collected as industrial waste. The lower calorific value of such RPF is also higher than the lower calorific value of RDF, and has the same calorific value as coal. However, low-quality plastics due to severe stains are not suitable for RPF, and the plastics that can be used as materials are limited.

The varieties and grades of RPF are classified into RPF-coque and RPF by the Japan RPF Industry Association, and the RPF grades are further classified into A, B and C.
The quality of RPF is high calorific value 25 MJ / kg or more, the mass fraction of total chlorine content is A category: 0.3% or less, B category: 0.3% or more and 0.6% or less, C category: 0. It is stipulated to be more than 6.6% and 2.0% or less.

In the explanation (January 2020) of the standard calorific value and carbon emission factor (revised in 2018) by energy source of the Ministry of Economy, Trade and Industry and the Agency for Natural Resources and Energy, the total calorific value (high calorific value) of coal (imported anthracite) is , 27.80 MJ / kg.
Here, the high calorific value is the calorific value including the energy of the amount (heat of vaporization) that the generated water vapor changes (condenses) into water after the fuel is burned and the temperature is returned to the temperature before combustion. .. On the other hand, the calorific value obtained by subtracting the latent heat of condensation of water vapor from the higher calorific value is the lower calorific value.

Therefore, it has a stable calorific value equivalent to that of coal from organic waste containing plastics, and has the same quality as the quality classification in the mass fraction of total chlorine defined by RPF, and is hydrophobic and water resistant. In addition, it is necessary to develop technology that can produce solid fuel with excellent safety in preventing spontaneous combustion and good transportation and storage efficiency.

Furthermore, the effects of "population decline" and "declining birthrate and aging population" are also having a great impact on the waste administration of local governments. In other words, it is very difficult to maintain a waste treatment facility of a scale commensurate with the current demographics in the future.

In addition, fiscal tightness has already become apparent in many local governments. The initial costs associated with the necessary renewal of waste treatment facilities, future maintenance costs, and the costs of dismantling and removal are also very high. For this reason, many local governments are putting off problems by preserving aging treatment facilities.

In addition, the waste currently incinerated by the local government contains a large amount of plastic mixtures. When such waste is simply incinerated, the calorific value of the waste and the generation of toxic gas are factors that damage the furnace.
On the other hand, plastic-based industrial waste has been exported to China and other countries, but importing itself has been banned because it causes environmental pollution in the importing countries themselves. However, existing industrial waste treatment facilities in Japan cannot treat the entire amount, which has become a major social issue.

Although the local government has no primary responsibility for the treatment of industrial waste, it also has the aspect of being asked for cooperation in the treatment. In addition, the treatment of combustible waste, including plastics, has become a major social problem on a global scale as it promotes increased carbon dioxide emissions.

The above-mentioned industrial waste treatment method is a method of incinerating combustible waste, but instead of this incinerator, subcriticality that reduces the molecular weight and volume of organic waste including plastics. A method using water treatment is known.

Sub-critical water treatment involves contact with gaseous sub-critical water under high temperature and high pressure, which is a high temperature below the critical temperature of water and a high pressure above the saturated steam pressure, thereby solubilizing organic waste. The method. Sub-critical water treatment can also decompose packages and plastic containers that could not be decomposed by conventional low molecular weight treatment. Therefore, even when the packaged food waste or the food waste contained in the plastic container is reduced in molecular weight, it can be solubilized together with the food waste without removing the package or the plastic container. ..

Patent No. 6640268

However, simply solubilizing organic waste by such sub-critical water treatment does not have a high efficiency of energy generation from organic waste, and there still remains a problem in consideration of practicality.

A treatment system is known in which organic waste is treated with sub-critical water and then the obtained treated product is fermented with methane. This processing system has large equipment, storage equipment, and the like. Moreover, since the product (output) is a flammable gas, it is difficult to implement it in society in urban areas under the current regulations such as the Building Standard Law, the City Planning Law, and the Fire Service Law.

Further, a treatment system for producing fuel pellets through a solid-liquid separation device, a drying device, a classification device, and a molding device after treating organic waste with subcritical water is also known (see, for example, Patent Document 1). However, the fuel pellets obtained by the treatment system described in Patent Document 1 do not have a stable calorific value equivalent to that of coal, contain a large amount of substances such as chlorine and potassium, and have a total chlorine content defined by RPF. It does not have the same quality as the quality classification in the mass fraction of.

In addition, the composition of organic waste differs depending on the collection area and time (paper / cloth, vinyl / synthetic resin / rubber / leather, wood / bamboo / straw, kitchen waste, incombustibles, etc.). There is also a problem that the calorific value of the treated product treated with critical water is liable to fluctuate.

In view of the above circumstances, the present invention has a calorific value equivalent to that of coal from organic waste containing plastics, contains almost no substances such as chlorine and potassium, and has a mass fraction of total chlorine content defined by RPF. It was decided to provide pellets having the same quality as the quality classification in the above, a waste treatment system capable of producing such pellets, and a waste treatment method.

According to one aspect of the invention, a waste treatment system is provided. This waste treatment system consists of a subcritical water treatment device that obtains a treated product by reducing the molecular weight of organic waste including plastics, a gas discharge mechanism that discharges gas components in the subcritical water treatment device, and a treated product. It is characterized by having a semi-carbonization device for semi-carbonizing the pellet raw material containing the above, and a pelletization device for pelletizing the pellet raw material or the pellet raw material after semi-carbonization to obtain pellets.

It may be provided in each of the following embodiments.
Further, the waste treatment system having a mixing device for mixing the processed product with woody biomass and obtaining the mixture as the pellet raw material.
The gas discharge mechanism is arranged between a suction device that sucks the gas component in the subcritical water treatment device and the suction device and the subcritical water treatment device, and removes fine particles in the gas component. The waste treatment system including a fine particle removing device.
Further, the waste treatment system having a water treatment device for treating the gas component that has passed through the gas discharge mechanism.
The water treatment device is a waste treatment system that is a device for performing pressure flotation treatment.
Further, the waste treatment system having a foreign matter removing device for removing solid foreign matter from the treated matter discharged from the sub-critical water treatment apparatus.
The semi-carbonization device is a waste treatment system that is a superheated steam generator that supplies superheated steam to the treated material in the sub-critical water treatment device.
Further, the waste treatment system including a decompression device for depressurizing the inside of the sub-critical water treatment device in an open state and a sterility treatment device for sterilizing the gas discharged from the decompression device.
Further, the waste treatment system having a pellet generator that uses the pellets as fuel to generate electricity.
Further, the waste treatment system having a water maker that produces water from air using electricity generated by the pellet generator.
At least one of the elements constituting the waste treatment system is the waste treatment system configured as a movable unit.
The unit is the waste treatment system housed in a container.
A step of reducing the molecular weight of organic waste containing plastics by subcritical water treatment to obtain a treated product, a step of solid-gas separating the treated product and a gas component, and a pellet raw material containing the treated product. A waste treatment method comprising a step of semi-carbonizing and pelletizing to obtain pellets.
Further, the waste treatment method comprising a step of mixing the processed product and woody biomass and obtaining the mixture as the pellet raw material prior to the step of obtaining the pellets.
A pellet obtained by semi-carbonizing and pelletizing a pellet raw material containing a processed product of organic waste containing plastics by sub-critical water treatment, and having a high calorific value of 30 MJ / kg or more.
The pellet having a mass fraction of total chlorine content of 0.3% or less as defined by JISZ7311: 2010.
The pellet raw material is the pellet containing the processed product and woody biomass.
Of course, this is not the case.

According to the present invention, organic waste containing plastics has a calorific value equivalent to that of coal, contains almost no substances such as chlorine and potassium, and has a quality in the mass fraction of total chlorine defined by RPF. It is possible to produce pellets with the same quality as the classification.

It is a conceptual diagram which shows the whole structure of 1st Embodiment of the waste treatment system of this invention. It is a conceptual diagram which shows the whole structure of the 2nd Embodiment of the waste treatment system of this invention. It is a conceptual diagram which shows the whole structure of the 3rd Embodiment of the waste treatment system of this invention. It is a conceptual diagram which shows the whole structure of the 4th Embodiment of the waste treatment system of this invention. It is a conceptual diagram which shows the whole structure of the 5th Embodiment of the waste treatment system of this invention. It is a conceptual diagram which shows the state which unitized the sub-critical water treatment apparatus in the waste treatment system of this invention. It is a conceptual diagram which shows the structure of the water treatment apparatus in the waste treatment system of this invention. It is a conceptual diagram which shows the structure of the pellet generator in the waste treatment system of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments.

<First Embodiment>
First, a first embodiment of the waste treatment system of the present invention will be described.
FIG. 1 is a conceptual diagram showing the overall configuration of the first embodiment of the waste treatment system of the present invention.
The waste treatment system (organic waste treatment system containing plastics) 100 shown in FIG. 1 includes a subcritical water treatment device 2 for treating organic waste 1 containing plastics with subcritical water, and a high-pressure boiler 3. have.

The high-pressure boiler 3 includes a combustion chamber for burning fuel and a heat exchanger arranged in the combustion chamber.
The high-pressure boiler 3 transfers the heat generated by combustion in the combustion chamber to the water passing through the heat exchanger to generate high-temperature and high-pressure steam. Then, the high-pressure boiler 3 supplies this steam to the sub-critical water treatment device 2.
For water supply to the high-pressure boiler 3, not only tap water can be used, but also digestive juice can be reused.

The sub-critical water treatment device 2 includes a pressure vessel and a shaft rotatably arranged in the pressure vessel and to which a stirring blade is attached.
The organic waste 1 in the pressure vessel is agitated while being conveyed toward the outlet of the pressure vessel by rotating the stirring blade as the shaft rotates. At this time, the organic waste 1 is subcritical water treated with steam supplied from the high-pressure boiler 3.

Sub-critical water treatment is low temperature by bringing gaseous sub-critical water into contact with organic waste 1 under high temperature and high pressure, which is high temperature below the critical temperature of water and high pressure above saturated steam pressure. It is a method of molecularization. Due to this low molecular weight, the organic waste 1 is decomposed to obtain a processed product.
The temperature of the gaseous sub-critical water is preferably about 180 to 230 ° C, more preferably about 190 to 220 ° C. The pressure is preferably about 15 to 25 atm, more preferably about 18 to 22 atm.

The specific temperature and pressure of the gaseous sub-critical water is preferably about 200 ° C. and about 20 atm.
The time in the sub-critical water treatment is appropriately set according to the type of the organic waste 1 and the like, and is not particularly limited, but is preferably about 0.1 to 10 hours, preferably about 0.5 to 5 hours. Is more preferable.

This sub-critical water has a dielectric constant of 15 to 45, which is equivalent to the dielectric constant of a low-polarity solvent. Therefore, many organic substances can be dissolved. Further, the subcritical water has an ion product of 1 × 10 ^-12 to 1 × 10 ^-11 mol ² / kg ² , and the ratio of separation into hydrogen ions and hydroxide ions is large, and therefore, a strong hydrolysis action. Is shown.
The dielectric constant of water at room temperature and under atmospheric pressure is about 80, and the ionic product of water at a temperature of about 25 ° C. and under atmospheric pressure is 1 × ^10-14 mol ² / kg ² .

In addition, sub-critical water can also decompose plastics such as polypropylene and polyethylene by the strong hydrolysis action as described above. For this reason, paper, vinyl, plastic, styrofoam, infectious medical waste, clothing containing chemical fibers, waste food as it is packaged, etc., which cannot be hydrolyzed by anaerobic bacteria or aerobic bacteria, are also decomposed. , Can be reduced in molecular weight.

The low molecular weight organic waste 1 (treated product) in the present invention preferably has a solubilization rate of 50% or more, more preferably 70% or more, and more preferably 85% or more. More preferred.
Here, the solubilization ratio is the ratio of the soluble organic matter to the total organic matter before pellet processing, and the higher the value, the lower the molecular weight of the organic matter.

Specific examples of the reduction of molecular weight of the organic waste 1 include decomposition into sugars such as carbohydrates, proteins and fats, amino acids, higher fatty acids and the like.
Further, the sub-critical water treatment in the sub-critical water treatment apparatus 2 is a batch treatment due to its nature, but in the present invention, it can be carried out at a ratio of several batches / day.

A gas discharge mechanism for discharging gas components in the sub-critical water treatment device 2 is connected to the sub-critical water treatment device 2. This gas discharge mechanism is composed of a centrifuge device (fine particle removing device) 9 and a vacuuming device (suction device) 10 arranged in order from the sub-critical water treatment device 2 side.
The evacuation device 10 sucks the gas component in the sub-critical water treatment device 2. This gas component includes a gas such as water vapor, a water-soluble substance associated with water vapor, and the like.

The gas component also contains fine particles, which are gas when passing through the centrifuge device (fine particle removing device) 9 arranged between the evacuation device 10 and the sub-critical water treatment device 2. And solids are separated and removed.
The fine particle removing device may be configured as long as it can be separated into a gas and a solid, and may be composed of, for example, a filter device, a column device, a scrubber device, an adsorption device, or the like, instead of the centrifugal separation device 9.

By sucking the gas component in the sub-critical water treatment device 2, it is possible to reduce the water content of the treated product (pellet raw material) and the water-soluble substances (chlorine, potassium, etc.). Thereby, pellets having the same quality as the quality classification in the mass fraction of the total chlorine content defined by RPF can be obtained.

When contaminated waste, contaminated soil, contaminated forest resources, etc. contaminated with radioactive substances are treated with subcritical water, cesium with a relatively long half-life discharged from the subcritical water treatment device 2 etc. There is also the advantage that radioactive substances can be removed.

A water treatment device 14 is connected to the evacuation device 10. The water treatment device 14 is a device that treats the gas component discharged from the evacuation device 10 with water. That is, the water treatment device 14 treats the gas component that has passed through the gas discharge mechanism with water.
Water treatment methods are roughly classified into physicochemical treatment and biochemical treatment, and the treatment method can be selected according to the purpose and standard of water quality treatment.

As the water treatment device 14, it is preferable to use a device that performs a pressurized flotation treatment.
FIG. 7 is a conceptual diagram showing the configuration of a water treatment device in the waste treatment system of the present invention.
The water treatment device 14 shown in FIG. 7 includes an agglutination reaction tank 60, a levitation tank 61, a circulation pump 62, and a pressurized water tank 63.
The gas component discharged from the sub-critical water treatment device 2 by suction of the vacuuming device 10 is subjected to agglutination treatment by adding a coagulant in the coagulation reaction tank 60.

Next, in the levitation tank 61, a large amount of fine air bubbles generated by the air generated by returning the pressurized water from the pressurized water tank 63 to the atmospheric pressure are generated. Water containing fine bubbles (hereinafter, also referred to as "fine bubble water") and water containing suspended solids are mixed, and the suspended solids are trapped in the fine bubbles. After that, it is floated by utilizing the buoyancy of the bubbles, the floating fine bubbles and suspended solids are removed by mechanical scraping or the like, and clean treated water is discharged from the lower part.

A part of the treated water can be circulated and used as circulating water by the circulation pump 62.
Further, in the pressurized flotation treatment, the fine bubble water is also referred to as fine bubble water. The decontamination effect can be enhanced by treating such fine bubble water with CO ₂ fine bubble water using CO ₂ instead of air and treating the gas component.

A sterilization / deodorization device (sterility treatment device) 22 for sterilizing the gas discharged from the decompression device is connected to the water treatment device 14. The decompression device decompresses the inside of the sub-critical water treatment device 2 in the open state. The sterility / deodorizing device 22 can deodorize the gas component discharged from the sub-critical water treatment device 2 after the water treatment and release it to the atmosphere.
The sterilization / deodorizing device 22 can be configured by, for example, an adsorption filter device or the like.
If necessary, the treated water in which a water-soluble substance or the like is dissolved is diluted and then drained.

Further, a classification device (foreign matter removing device) 8 is connected to the sub-critical water treatment device 2. The classification device 8 removes solid foreign matter from the treated material discharged from the sub-critical water treatment device 2.
Examples of the classification device 8 include a trommel, a sieving device, and the like. Above all, it is preferable to use trommel. By using trommel, not only foreign matter can be removed but also the processed material can be made uniform.

Since the organic waste 1 used in the present invention contains general waste, various foreign substances may be mixed depending on the state of waste collection in each local government or business entity.
Examples of foreign substances include pottery pieces (ceramic pieces), bottle pieces (glass pieces), metal pieces, and the like. By removing such foreign matter, it is possible to prevent non-uniformity of the processed material (pellet raw material) and a decrease in calorific value.

A solidifying device / semi-carbonizing device 4 is connected to the classification device 8. Further, although not shown, the solidification device / semi-carbonization device 4 includes a mixing device that mixes the processed product and the woody biomass 5 to obtain the mixture as a pellet raw material.
The mixture containing the treated product (pellet raw material) may be semi-carbonized by a semi-carbonized device that semi-carbonizes the pellet raw material containing the treated product, and then pelletized by a solidifying device (pelletizing device), and vice versa. You may. Here, the pelletizing device pelletizes the pellet raw material or the pellet raw material after semi-carbonization to obtain pellets.

The composition of waste varies depending on the collection area and time, and the calorific value of the treated product obtained by sub-critical water treatment varies. The woody biomass 5 is mixed with the processed product for the purpose of complementing (adjusting) the fluctuation of the calorific value. As a result, pellets having a stable calorific value equivalent to that of coal and having the same quality as the quality category in the mass fraction of total chlorine defined by RPF (referred to as "solid fuel" in the figure). Can be satisfactorily manufactured in an extremely short time.
Depending on the type of waste and the like, if the pellets having the above quality can be produced by using only the treated product, the mixing of the woody biomass 5 can be omitted.

As the woody biomass 5 that can be used in the present invention, the end portion (so-called “scrap material”) generated when the raw wood (log) cut from the mountain is processed into wood (board material, pillar material, etc.). Examples include crushed materials such as bark of logs and waste paper made from wood.
The obtained pellets generate CO ₂ when burned, but in the case of woody biomass 5, they are carbon-neutral because they only return the CO ₂ absorbed by the trees in the forest to the atmosphere. Therefore, the pellet-like "biomass energy fuel" obtained in the present invention can be said to be an ecological fuel.

The pellets obtained in the present invention are not particularly limited in size, shape and the like as long as they can be suitably used as fuel for a target device (for example, a pellet generator 6 described later).
Further, the pellet obtained by semi-carbonization as in the present invention is composed of highly pure carbide while suppressing the water content and the content of volatile organic components. Therefore, the pellets have an increased calorific value and are excellent in durability and storage stability in a natural environment.

The semi-carbonization treatment by the semi-carbonization device is performed by heat-treating the pellet raw material in an atmosphere having a low oxygen concentration.
The temperature of the heat treatment is preferably about 200 to 700 ° C, more preferably about 200 to 300 ° C. The heat treatment time is preferably about 1 to 24 hours, more preferably about 1 to 3 hours.
By performing the semi-carbonization treatment under such conditions, the pellet raw material can be reliably put into a semi-carbonized state.
Here, the semi-carbonized state means a state in which about half of the pellet raw material is converted into carbide.

As the solidifying device, for example, a strand type extruder, a hot cut type extruder, or the like can be used.

Further, in the present embodiment, at least one of the elements constituting the waste treatment system 100 is configured as a movable unit.
FIG. 6 is a conceptual diagram showing a state in which the sub-critical water treatment apparatus in the waste treatment system of the present invention is unitized.
In FIG. 6, the sub-critical water treatment device 2 is housed in the container 40 and loaded on the large vehicle 41. That is, in the example of FIG. 6, the unit is housed in 40 in the container. In addition, M in the figure represents a motor, and the organic waste 1 is transferred or agitated in the sub-critical water treatment apparatus 2 by the rotational force thereof.

The sub-critical water treatment device 2 housed in the container 40 in this way is separated from the other components of the waste treatment system 100, and can be easily moved together with the container 40.
Further, the other components of the waste treatment system 100 described above and described later can also be housed in the container in the same manner and can be easily moved.
In this case, the waste treatment system 100 can be transported, temporarily assembled and installed according to the area where the organic waste 1 is treated, so that it can be socially implemented in an urban area. Further, after the treatment, the waste treatment system 100 can be disassembled and carried out.

Further, the operation of the sub-critical water treatment apparatus 2 shown in FIG. 6 can be a batch treatment with an operation time of about 2 hours.
For this reason, the sub-critical water treatment device 2 mounted on the vehicle can be patrolled in search of equipment after the solidification device / semi-carbonization device 4 which is almost fixedly arranged at a plurality of places. Contributes to reduction of initial capital investment.

The waste treatment system 100 can be configured to enable AI treatment 15.
The AI treatment 15 collects and accumulates various data (temperature, pressure, flow rate, valve open / close degree, electric energy, water amount, etc.) by installing a sensor in the device group used in the waste treatment system 100. be able to.
Then, the AI process 15 can optimize and improve the operation timing and time of each device group by an integrated algorithm utilizing AI based on the accumulated data.

Next, a method of using the waste treatment system 100 as described above (a waste treatment method of the present invention) will be described.
[1] First, the organic waste 1 containing plastics is put into the sub-critical water treatment apparatus 2 as a material to be treated.
[2] Next, the high-pressure boiler 3 generates high-temperature and high-pressure steam, which is supplied into the sub-critical water treatment device 2.
At this time, in the sub-critical water treatment apparatus 2, the organic waste 1 comes into contact with high-temperature and high-pressure steam (gaseous sub-critical water), and the molecular weight is reduced due to its high hydrolysis action, so that the treated product becomes Generate. That is, in this step, organic waste containing plastics is treated with sub-critical water.

[3] At this time, the gas component in the sub-critical water treatment device 2 is discharged by the vacuuming device 10 (solid air separation from the treated product), and the fine particles contained in the gas component are separated by the centrifuge device 9. Is removed as it passes through. That is, in this step, the processed product and the gas component are separated by solid air.
[4] Next, the gas component discharged from the evacuation device 10 is water-treated by the water treatment device 14.
The gas component discharged from the water treatment device 14 is released to the atmosphere after passing through the sterilization / deodorizing device 22. The treated water is diluted as necessary and then drained.

[5] On the other hand, the processed material in the sub-critical water treatment device 2 is discharged from the outlet and supplied to the classification device 8. The classification device 8 removes solid foreign matter mixed in the processed material.
[6] Next, the processed product is supplied to the solidifying device / semi-carbonizing device 4, and is first mixed with the woody biomass 5 to obtain a mixture (pellet raw material including the processed product). That is, in this step, prior to the step of obtaining pellets, the processed product and woody biomass are mixed to obtain a mixture thereof as a pellet raw material. That is, the pellet raw material includes a processed product and woody biomass.
[7] Next, this mixture is semi-carbonized by a semi-carbonizing device and pelletized by a solidifying device. Through the above steps, pellets (also referred to as "black pellets") are obtained. That is, in this step, the pellet raw material containing the processed product is semi-carbonized and pelletized to obtain pellets.

<Second Embodiment>
Next, a second embodiment of the waste treatment system of the present invention will be described.
Hereinafter, the difference between the waste treatment system of the second embodiment and the waste treatment system of the first embodiment will be described, and the description of the same matters will be omitted.
FIG. 2 is a conceptual diagram showing the overall configuration of the second embodiment of the waste treatment system of the present invention.
In the waste treatment system 200 shown in FIG. 2, a pellet generator 6 that mainly uses pellets as fuel to generate electricity and a water making machine 7 that produces water from air using electricity generated by the pellet generator 6 are added. It is the same as the waste treatment system 100 except that it is done.

In the second embodiment, the pellets (solid fuel) produced by the solidifying device / semi-carbonizing device 4 are used as fuel for power generation in the pellet generator 6.
Here, LP gas may be used as an auxiliary fuel in the pellet generator 6.
The pellet generator 6 has a mechanism using pellets as fuel. FIG. 8 is a conceptual diagram showing the configuration of a pellet generator in the waste treatment system of the present invention.
The pellet generator 6 shown in FIG. 8 is composed of a fuel supply device 81, a gasification device 82, an ash discharge device 83, a gas cooling device 84, a gas filter 85, a gas engine 86, and a generator 87.

In the pellet generator 6, first, the pellets are conveyed into the gasification device 82 by the fuel supply device 81 arranged at the uppermost stream. The gasification device 82 has a vaporization function and vaporizes the conveyed pellets. At this time, the components that have not been vaporized are discharged to the outside by the ash discharge device 83.
Next, the gas component vaporized in the gasifier 82 is transferred to the gas cooling device 84 and cooled.

The cooled gas component removes unnecessary components through the gas filter 85 and is transferred to the gas engine 86 installed on the downstream side. The gas engine 86 operates using the gas component cooled by the gas cooling device 84 as fuel, and the generator 87 is operated by this power.
In this way, electricity is generated in the generator 87. As described above, LP gas may be used as an auxiliary fuel for this power generation.
The electricity may be temporarily charged to a storage battery, a power storage facility, a next-generation vehicle, or the like (not shown).

The obtained electricity can be used in a water maker (water maker that makes water from air) 7 to produce water and can be supplied as a good energy source in the region as a small-scale power generation facility.
For this water maker 7, for example, Japan-Israel Research Institute / product name "Watergen" model number; GEN-350 (capacity: 900L / Day) or model number; GENNY (capacity: 27L / Day), AQUAM, Inc. The model number of the company / product name "Eco-blue"; 30sME / 30JP (capacity: 10 to 15L / Day) or the like can be used.

Further, according to the waste treatment system 200, it is possible to optimize the power supply-demand balance of the local governments and the communities around the enterprises that have introduced the waste treatment system 200.
In particular, the waste treatment system 200 will function as a small-scale power generation facility as a good energy source for the region, and AI treatment (new information technology) 15 will replace large-scale power plants in homes, buildings, and factories. It is also possible to integrate a plurality of small-scale power generation facilities and power storage facilities scattered around such as, and to remotely control them so that they can function as one power plant.

<Third Embodiment>
Next, a third embodiment of the waste treatment system of the present invention will be described.
Hereinafter, the difference between the waste treatment system of the third embodiment and the waste treatment system of the first embodiment will be described, and the description of the same matters will be omitted.
FIG. 3 is a conceptual diagram showing the overall configuration of the third embodiment of the waste treatment system of the present invention.
The waste treatment system 300 shown in FIG. 3 is the same as the waste treatment system 100 except that it can treat infectious waste.

In the waste treatment system 300, a decompression device (not shown) for reducing the pressure inside the open sub-critical water treatment device 2 is provided in the middle of the line connecting the sub-critical water treatment device 2 and the sterilization / deodorization device 22. Have been placed.
Here, medical waste generated by medical practice (“infectious waste” under the Waste Disposal Law) may be in contact with the pathogen of the patient, and is a risk belonging to biological danger. Also have.

According to the waste treatment system 300 of the third embodiment, even when such infectious waste is treated, if the decompression device is operated at the time of putting the infectious waste into the sub-critical water treatment device 2, the pathogen can be treated. It is possible to prevent scattering to the surrounding environment.
Further, the air exposed to the infectious waste in the sub-critical water treatment device 2 is exhausted to the decompression device and then supplied to the sterilization / deodorization device 22 for sterilization treatment.

When the sterilization / deodorizing device 22 is composed of an adsorption filter, it is preferably heated to about 150 to 250 ° C. in order to sufficiently enhance the sterilization effect.
With the above configuration, it is possible to smoothly put the infectious waste into the sub-critical water treatment device 2 while reducing the risk of infection by the worker.

In addition, it has become difficult to use conventional small-sized incineration equipment for infectious wastes due to the tightening of regulations on tyoxins.
In principle, infectious waste should be treated in facilities such as medical organizations, and ideally, it should be treated promptly at the place where infectious waste is generated.
According to the waste treatment system 300 of the third embodiment, the above requirements can be satisfied, which is preferable.

<Fourth Embodiment>
Next, a fourth embodiment of the waste treatment system of the present invention will be described.
Hereinafter, the difference between the waste treatment system of the fourth embodiment and the waste treatment system of the first embodiment will be described, and the description of the same matters will be omitted.
FIG. 4 is a conceptual diagram showing the overall configuration of the fourth embodiment of the waste treatment system of the present invention.
The waste treatment system 400 shown in FIG. 4 is the same as the waste treatment system 100 except that the configuration of the semi-carbonization device is different.

In the present embodiment, the semi-carbonization device is composed of a superheated steam generator 20 that supplies superheated steam to the processed material in the sub-critical water treatment device. Specifically, the semi-carbonization device is connected to a high-pressure boiler 3 and is composed of a superheated steam generator 20 that generates high-temperature steam (superheated steam) at a relatively low pressure.
Therefore, in the present embodiment, instead of the solidifying device / semi-carbonizing device 4, the solidifying device 21 connected to the classifying device 8 is provided.
The steam from the high-pressure boiler 3 is converted into superheated steam by the superheated steam generator 20 and supplied into the sub-critical water treatment device 2. As a result, the charged organic waste 1 can be semi-carbonized while being contained in the sub-critical water treatment device 2. Therefore, it is possible to simplify the process of the treatment process and downsize the waste treatment system 400.

The temperature of the superheated steam is preferably about 200 to 800 ° C, more preferably about 500 to 700 ° C. Further, the pressure of the superheated steam is more preferably about atmospheric pressure.
The treatment time with superheated steam is preferably about 1 to 24 hours, more preferably about 1 to 3 hours.
By performing the semi-carbonization treatment under the above conditions, the pellet raw material can be reliably put into a semi-carbonized state.
The superheated steam generator 20 may be arranged inside the sub-critical water treatment device 2 or outside the sub-critical water treatment device 2.

<Fifth Embodiment>
Next, a fifth embodiment of the waste treatment system of the present invention will be described.
Hereinafter, the difference between the waste treatment system of the fifth embodiment and the waste treatment system of the first embodiment will be described, and the description of the same matters will be omitted.
FIG. 5 is a conceptual diagram showing the overall configuration of the fifth embodiment of the waste treatment system of the present invention.
The waste treatment system 500 shown in FIG. 5 is the same as the waste treatment system 100 except that the low pressure boiler 31 and the steam compressor 30 are used instead of the high pressure boiler 3.

The low-pressure boiler 31 converts the supplied water into steam, pressurizes it via the steam compressor 30, and can supply it into the sub-critical water treatment device 2 in this state.
According to such a configuration, it is possible to reduce high-pressure and high-temperature parts in the entire waste treatment system 500, and it is possible to reduce the size of the waste treatment system 500.
In particular, the low-pressure boiler 31 can be designed to have a lower height than the high-pressure boiler 3, and is therefore suitable for in-vehicle use.

The pellet of the present invention is made by semi-carbonizing and pelletizing a pellet raw material containing a processed product of organic waste containing plastics by sub-critical water treatment. The pellet raw material contains a processed product and woody biomass depending on the quality of the target pellet.
The high calorific value of such pellets is 25 MJ / kg or more, and preferably 27 MJ / kg or more. The upper limit of the high calorific value of the pellet is usually 40 MJ / kg. The calorific value of the pellets can be adjusted by changing the amount of woody biomass added.
Further, the pellets preferably have a mass fraction of total chlorine content of 0.3% or less, and more preferably 0.1% or less, as defined by JIS Z 7311: 2010. The lower limit of the mass fraction of total chlorine is usually 0.01%.
Pellets satisfying such conditions can be considered to have a calorific value equivalent to that of coal and to have a high quality equivalent to the quality classification in the mass fraction of total chlorine defined by RPF.

Although the waste treatment system, the waste treatment method and the pellets of the present invention have been described above, the present invention is not limited to the configuration of the above-described embodiment.
For example, the waste treatment system and pellets of the present invention may be added to any other configuration or have been replaced with any configuration that performs the same function, respectively, in the configuration of the above-described embodiment. good.
Further, the waste treatment method of the present invention may be added to any other step or may be replaced with any step exhibiting the same function in the configuration of the above-described embodiment.
Further, the waste treatment system and the waste treatment method of the present invention may be combined with any configuration of the above-mentioned first to fifth embodiments, respectively.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
1. 1. Production of pellets (Example 1)
The waste treatment system shown in FIG. 1 was used to produce pellets from organic waste containing plastics.
In the sub-critical water treatment, the temperature of the sub-critical water was set to about 200 ° C., the pressure was set to about 20 atm, and the treatment time was set to 2 hours.

(Example 2)
Using the waste treatment system shown in FIG. 4, pellets were produced from organic waste containing plastics having the same composition as in Example 1 in the same manner as in Example 1.
(Example 3)
Using the waste treatment system shown in FIG. 5, pellets were produced from organic waste containing plastics having the same composition as in Example 1 in the same manner as in Example 1.
(Example 4)
Pellets were produced in the same manner as in Example 1 from the organic waste containing plastics having the same composition as in Example 1 except that the mixing of woody biomass was omitted.

(Comparative Example 1)
Using the waste treatment system shown in FIG. 1 omitting the semi-carbonization device, pellets were produced from organic waste containing plastics having the same composition as in Example 1 in the same manner as in Example 1.
(Comparative Example 2)
Using the waste treatment system shown in FIG. 1, omitting the centrifuge and evacuation device, pellets were made from organic waste containing plastics having the same composition as in Example 1 in the same manner as in Example 1. Manufactured.

2. 2. Measurement Examples and Comparative Examples For the obtained pellets, the high calorific value and the mass fraction of total chlorine content are obtained according to the method specified in JIS Z 7311: 2010 “Waste-derived solidified fuel (RPF) such as paper and plastic”. The rate was measured.
The results are shown in Table 1 below.

1: Organic waste 2: Subcritical water treatment equipment 3: High-pressure boiler 4: Semi-carbonization equipment 5: Woody biomass 6: Pellet generator 7: Water making machine 8: Classification device 9: Centrifugal separation device 10: Vacuum pumping device 14: Water treatment device 15: AI treatment 20: Superheated steam generator 21: Solidification device 22: Deodorization device 30: Steam compressor 31: Low pressure boiler 40: Container 41: Large vehicle 60: Aggregation reaction tank 61: Floating tank 62: Circulation Pump 63: Pressurized water tank 81: Fuel supply device 82: Gasification device 83: Ash discharge device 84: Gas cooling device 85: Gas filter 86: Gas engine 87: Generator 100: Waste treatment system 200: Waste treatment system 300 : Waste treatment system 400: Waste treatment system 500: Waste treatment system

Claims (17)

Sub-critical water treatment equipment that obtains treated products by reducing the molecular weight of organic waste containing plastics,
A gas discharge mechanism that discharges gas components in the sub-critical water treatment device,
A semi-carbonization device that semi-carbonizes the pellet raw material containing the processed material,
A waste treatment system comprising a pelletizing apparatus for pelletizing the pellet raw material or the pellet raw material after semi-carbonization to obtain pellets. The waste treatment system according to claim 1, further comprising a mixing device for mixing the processed product with woody biomass and obtaining the mixture as the pellet raw material. The gas discharge mechanism is arranged between a suction device that sucks the gas component in the subcritical water treatment device and the suction device and the subcritical water treatment device, and removes fine particles in the gas component. The waste treatment system according to claim 1 or 2, further comprising a fine particle removing device. The waste treatment system according to any one of claims 1 to 3, further comprising a water treatment device for treating the gas component that has passed through the gas discharge mechanism. The waste treatment system according to claim 4, wherein the water treatment device is a device for performing pressure flotation treatment. The waste treatment system according to any one of claims 1 to 5, further comprising a foreign matter removing device for removing solid foreign matter from the treated matter discharged from the sub-critical water treatment apparatus. The waste treatment system according to any one of claims 1 to 6, wherein the semi-carbonization device is a superheated steam generator that supplies superheated steam to the treated material in the sub-critical water treatment device. Further, a decompression device for depressurizing the inside of the sub-critical water treatment device in an open state, and a decompression device.
The waste treatment system according to any one of claims 1 to 7, further comprising a sterilization treatment device for sterilizing the gas discharged from the decompression device. The waste treatment system according to any one of claims 1 to 8, further comprising a pellet generator that uses the pellets as fuel to generate electricity. The waste treatment system according to any one of claims 1 to 9, further comprising a water maker that produces water from air using electricity generated by the pellet generator. The waste treatment system according to any one of claims 1 to 10, wherein at least one of the elements constituting the waste treatment system is configured as a movable unit. The waste treatment system according to claim 11, wherein the unit is housed in a container. A process of reducing the molecular weight of organic waste containing plastics by subcritical water treatment to obtain a processed product, and
The step of solidly separating the processed product and the gas component, and
A waste treatment method comprising a step of semi-carbonizing a pellet raw material containing the treated product and pelletizing the pellet raw material to obtain pellets. The waste treatment method according to claim 13, further comprising a step of mixing the processed product and woody biomass and obtaining the mixture as the pellet raw material prior to the step of obtaining the pellets. A pellet made by semi-carbonizing and pelletizing a pellet raw material containing a processed product of organic waste containing plastics by sub-critical water treatment, and having a high calorific value of 25 MJ / kg or more. The pellet according to claim 15, wherein the mass fraction of total chlorine content specified in JIS Z 7311: 2010 is 0.3% or less. The pellet according to claim 15 or 16, wherein the pellet raw material contains the processed product and woody biomass.

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