Hydrothermal treatment system

Abstract

The hydrothermal treatment system (1) includes: a hydrothermal treatment device (10) which performs a hydrothermal reaction of waste containing organic matter; an adjustment tank (11) which wets a hydrothermal treatment product obtained from the hydrothermal reaction; a first transport device (21) which transports the hydrothermal treatment product which is wetted in the adjustment tank (11); a pressure-separation device (12) which applies pressure to the hydrothermal treatment product transported by the first transport device (21) to separate the transported hydrothermal treatment product into hydrothermal treatment liquid and residue; a solubilization tank (13) which stores and heats up the hydrothermal treatment liquid separated by the pressure-separation device (12); a second transport device (22) which transports the hydrothermal treatment liquid which is heated up and solubilized in the solubilization tank (13) back to the adjustment tank (11); and a gas production device (14) which produces gas by utilizing the hydrothermal treatment liquid stored in the solubilization tank (13). The second transport device (22) transports the hydrothermal treatment liquid to the gas production device (14) when the concentration of organic matter contained in the hydrothermal treatment liquid stored in the solubilization tank (13) is at a predetermined concentration. FIG. 1

Description

Hydrothermal Treatment System

[0001] The present invention relates to a hydrothermal treatment system for producing gas from organic-containing waste.

[0002] Systems have been developed that involve hydrothermally reacting organic matter-containing waste, such as municipal solid waste (food waste), woody waste (paper, plants, etc.), livestock manure, and sludge, with high-temperature, high-pressure steam to solubilize them (hydrothermal treatment), separating a liquid (hydrothermally treated liquid) such as a solution or slurry from the hydrothermally treated organic matter-containing waste (hydrothermally treated product), and using the liquid to generate gas, e.g., methane fermentation, using microorganisms or bacteria (see, for example, Patent Documents 1 and 2). To separate the hydrothermally treated liquid from the hydrothermally treated product, these systems can use, for example, a screen or a screw press as described in Patent Document 3.

[0003] JP 2009-119378 A JP 2019-181397 A JP 2011-200836 A

[0004] Generally, organic-containing waste collected by garbage trucks and organic-containing waste stored in garbage pits at waste incineration plants contains not only organic matter that contributes to gas generation, but also organic matter that does not or does not contribute much to gas generation (e.g., plastics), and inorganic matter such as metal and glass, which are not completely removed and remain. Furthermore, the ratio of organic matter to inorganic matter contained in the collected or stored organic-containing waste, the ratio of kitchen waste to paper even among organic matter, and the ratio of organic matter that contributes to gas generation to organic matter that contributes very little (i.e., the ratio of each of the multiple components in a given amount of organic-containing waste) vary depending on the region, season, and time of day.

[0005] Furthermore, generally, regardless of the ratio of each component in the organic-containing waste, in a hydrothermal treatment device, a predetermined amount of organic-containing waste is hydrothermally treated for a predetermined period of time (predetermined time), and once the predetermined period of time has elapsed, the hydrothermal treatment is terminated and the hydrothermally treated product is removed from the hydrothermal treatment device. Therefore, the properties of the hydrothermally treated product that is removed vary depending on the ratio of each component in the organic-containing waste. For example, a hydrothermally treated product that has little moisture and is sandy or powdery may be obtained, or a hydrothermally treated product that has a lot of moisture and is muddy or liquid may be obtained.

[0006] On the other hand, when using a hydrothermally treated liquid to generate gas using microorganisms or bacteria, for example, to generate methane through methane fermentation, it is desirable for the hydrothermally treated liquid to contain as much fine organic matter as possible. For this reason, as described in Patent Document 3, it is preferable to use a pressurized screw press when separating the hydrothermally treated liquid from the hydrothermally treated product. However, pressing a hydrothermally treated product with a low moisture content (e.g., sand-like) using a screw press is not recommended because it increases power consumption and may cause malfunctions.

[0007] Furthermore, when gas is generated by microorganisms or bacteria using a hydrothermal-treated liquid, the concentration of fine organic matter contained in the hydrothermal-treated liquid is an important factor for increasing the gas generation efficiency. However, since the concentration of the organic matter differs significantly between hydrothermally treated products with high moisture content and those with low moisture content, it has been difficult to stably generate gas in gas generating devices such as methane fermentation devices.

[0008] Therefore, an object of the present invention is to provide a hydrothermal treatment system that can stably generate gas regardless of the ratio of each component contained in organic-matter-containing waste.

[0009] The hydrothermal treatment system of the present invention comprises a hydrothermal treatment device that hydrothermally reacts organic matter-containing waste, an adjustment tank that humidifies the hydrothermally reacted hydrothermal treatment product, a first transfer device that transfers the hydrothermally treated product humidified in the adjustment tank, a pressure separation device that pressurizes the hydrothermally treated product transferred in the first transfer device to separate it into a hydrothermally treated liquid and a residue, a solubilization tank that stores and heats the hydrothermally treated liquid separated in the pressure separation device, a second transfer device that returns the hydrothermally treated liquid heated and solubilized in the solubilization tank to the adjustment tank, and a gas generator that generates gas using the hydrothermally treated liquid stored in the solubilization tank, wherein the second transfer device returns the hydrothermally treated liquid to the adjustment tank when the concentration of organic matter contained in the hydrothermally treated liquid stored in the solubilization tank is less than a predetermined concentration that is a concentration of organic matter suitable for gas generation by microorganisms or bacteria, and transfers the hydrothermally treated liquid to the gas generator when the concentration of organic matter is equal to or greater than the predetermined concentration.

[0010] According to the present invention, gas can be generated stably regardless of the ratio of each component contained in the organic-substance-containing waste.

[0011] 1 is a schematic diagram showing a hydrothermal treatment system according to an embodiment. FIG. 2 is a schematic diagram showing an example of a second facility of the hydrothermal treatment system according to an embodiment.

[0012] The hydrothermal treatment system of the present invention will be described below with reference to the drawings. The configurations shown below are merely examples and are not intended to exclude various modifications or applications of techniques not explicitly stated. The configurations shown below can be modified in various ways without departing from the essential constituent elements and spirit of the present invention.

[0013] FIG. 1 is a schematic diagram showing a hydrothermal treatment system 1 according to this embodiment. The hydrothermal treatment system 1 solubilizes organic-containing waste by hydrothermal reaction with high-temperature, high-pressure steam (hereinafter referred to as "hydrothermal treatment"), and generates gas using microorganisms or bacteria using a liquid (hereinafter referred to as the "hydrothermally treated liquid") such as a solution, mixed liquid, or slurry separated from the hydrothermally treated organic-containing waste (hereinafter referred to as the "hydrothermally treated product"). The hydrothermal treatment system 1 is configured to include at least a hydrothermal treatment device 10, an adjustment tank 11, a first transfer device 21, a pressure separation device 12, a solubilization tank 13, a second transfer device 22, and a gas generator 14. The entire configuration of the hydrothermal treatment system 1 shown in FIG. 1 will now be described in detail.

[0014] The hydrothermal treatment device 10 is a device that hydrothermally treats organic waste. Examples of organic waste that can be input into the hydrothermal treatment device 10 include household kitchen waste (food waste), woody waste, livestock manure, and sludge. Organic waste collected by garbage trucks or stored in waste pits at waste disposal plants can be input directly into the hydrothermal treatment device 10, or inorganic matter can be removed from the organic waste before input into the hydrothermal treatment device 10. Kitchen waste, paper, and plants containing organic matter suitable for gas generation can be selectively extracted from the organic waste, and the extracted kitchen waste, paper, or plants can be input into the hydrothermal treatment device 10. The hydrothermal treatment device 10 can also hydrothermally treat disposable diapers, which have recently become a problem for disposal in elderly care facilities and the like. As will be made clear later, in the hydrothermal treatment system 1, even if the ratio of each content to a predetermined amount of organic-containing waste handled by the hydrothermal treatment device 10 in one hydrothermal treatment varies greatly for each organic-containing waste handled in each of the multiple hydrothermal treatments performed, gas can be stably generated in the gas generator 14 described below. Hydrothermal treatment is performed for a predetermined time in the hydrothermal treatment device 10, and the hydrothermal treated product discharged from the hydrothermal treatment device 10 is stored in the adjustment tank 11.

[0015] The adjustment tank 11 is a device that humidifies the hydrothermally treated product discharged from the hydrothermal treatment device 10 to adjust the properties of the hydrothermally treated product. Here, "humidifying" the hydrothermally treated product not only means wetting the hydrothermally treated product with water or a liquid, but also means immersing the hydrothermally treated product in water or a liquid. The hydrothermally treated liquid stored in the solubilization tank 13, which will be described later, is poured into the adjustment tank 11, thereby humidifying the hydrothermally treated product stored in the adjustment tank 11. In addition to the hydrothermally treated liquid, tap water (not shown) or recycled water, which will be described later, may be poured into the adjustment tank 11 as appropriate. Furthermore, an agitator may be installed in the adjustment tank 11 to agitate and mix the hydrothermally treated product stored in the adjustment tank 11 with the liquid or water that is poured in. When an agitator is installed, the adjustment tank 11 can adjust the properties of the hydrothermally treated product in a short period of time. For example, if the hydrothermally treated product stored in the adjustment tank 11 is sandy, the hydrothermally treated product can be converted into a slurry in a short time by operating the agitator while performing the above-mentioned liquid or water injection. The agitator may be any device, such as air agitation or mechanical agitation, that is capable of agitating and mixing the hydrothermally treated product stored in the adjustment tank 11 with the liquid or water being injected.

[0016] The hydrothermal treatment device 10 and the adjustment tank 11 are facilities that hydrothermally treat organic matter-containing waste and humidify and store the hydrothermally treated product obtained by the hydrothermal treatment, and are components of a first facility 2 that performs the first stage of treatment in the hydrothermal treatment system 1. As will be described later, a facility that pressurizes the hydrothermally treated product stored in the first facility 2 to separate the hydrothermally treated liquid (hereinafter referred to as "pressure separation") and solubilizes the hydrothermally treated liquid obtained by the pressure separation is a second facility 3 that performs the second stage of treatment in the hydrothermal treatment system 1. Furthermore, a facility that generates gas using the hydrothermally treated liquid solubilized in the second facility 3 is a third facility 4 that performs the third stage of treatment in the hydrothermal treatment system 1.

[0017] The first transfer device 21 transfers the hydrothermally treated product humidified in the adjustment tank 11 of the first facility 2 to the second facility 3. When the first facility 2 and the second facility 3 are installed close to each other, for example, when the first facility 2 and the second facility 3 are installed on the same or nearby premises and the distance between them is less than approximately 500 m, the first transfer device 21 is preferably a pipeline connected to the adjustment tank 11 of the first facility 2 and the pressure separation device 12 of the second facility 3 and equipped with a fracturing pump that pressure-transfers the hydrothermally treated product whose properties have been adjusted in the adjustment tank 11 to the pressure separation device 12. A pipeline is generally configured by connecting multiple pipes to form a single path. In this case, the hydrothermally treated product stored in the adjustment tank 11 of the first facility 2 is transferred through the pipeline to the pressure separation device 12 of the second facility 3 while being crushed by a fracturing pump. Since the hydrothermally treated product can be finely divided by the fracturing pump during transfer, the load on the pressure separation device 12 (e.g., a screw press) described below can be reduced.

[0018] In the following, when two of the first facility 2, the second facility 3, and the third facility 4 are said to be installed "close to each other," this means that the two facilities are installed on the same or different premises with a distance of less than approximately 500 m between them.

[0019] On the other hand, when the first facility 2 and the second facility 3 are installed far from each other, the first transfer device 21 is preferably a vehicle (e.g., a vacuum truck) equipped with a storage tank or the like. For example, if the first facility 2 and the second facility 3 are installed approximately 500 m or more apart from each other, they can be said to be installed "far from each other," whether they are on the same site or different sites. In this case, the hydrothermally treated product stored in the adjustment tank 11 of the first facility 2 is loaded onto a vehicle and transported to the pressure separation device 12 of the second facility 3, and the transported hydrothermally treated product is introduced into the pressure separation device 12.

[0020] Here, the automobile may be a human-driven automobile, or an autonomous automobile in which operation is controlled not by a human but by a computer such as artificial intelligence (AI). Alternatively, a central control room may be provided in the hydrothermal treatment system 1, and the operation of the automobile may be controlled by a human remotely monitoring the system using surveillance cameras. In this case, if surveillance cameras are installed in the equipment, devices, and facilities included in the hydrothermal treatment system 1, these can be remotely monitored from the central control room, thereby improving the safety of the operation of the hydrothermal treatment system 1. Furthermore, the hydrothermal treatment system 1 can be configured so that the operation of each of the equipment, devices, and facilities included in the hydrothermal treatment system 1 is controlled from the central control room, and the operation of the hydrothermal treatment system 1 can be fully automated by using AI.

[0021] In the following, when two of the first facility 2, second facility 3, and third facility 4 are said to be installed "far away," it means that the two facilities are installed on the same or different premises, with the distance between them being approximately 500 meters or more. Furthermore, in the following, when referring to an "automobile," the automobile may be a human-driven automobile or an autonomous automobile. The automobile may also be a automobile whose driving is remotely monitored and controlled by a human.

[0022] The pressure separation device 12 of the second facility 3 pressurizes the hydrothermally treated product transferred from the adjustment tank 11 of the first facility 2 by the first transfer device 21 to separate it into a hydrothermally treated liquid and a residue (the material remaining after the hydrothermally treated liquid is separated from the hydrothermally treated product). The hydrothermally treated liquid is also referred to as a fermentation-suitable material, and the residue is also referred to as a fermentation-unsuitable material. The pressure separation device 12 may be configured, for example, as shown in FIG. 2 , with a rotary drum screen 12A disposed in the front stage and a screw press 12B disposed in the rear stage. The rotary drum screen 12A may be, for example, a punched metal drum screen device as described in Patent Publication No. 6384015 issued by Mitsubishi Heavy Industries Environmental & Chemical Engineering Co., Ltd. Furthermore, the screw press 12B may be, for example, a dehydration system as described in FIG. 13 of Patent Publication No. 6734496 issued by Mitsubishi Heavy Industries Environmental & Chemical Engineering Co., Ltd. The pressure separation device 12 requires careful consideration of the mesh size, opening ratio, and screw pitch (distance between the screw and the outlet) because the recovery rate of the hydrothermally treated liquid and the removal rate of materials unsuitable for fermentation are affected by the moisture content and viscosity of the hydrothermally treated product. The dehydration system shown in Figure 13 of the registered publication of Japanese Patent No. 6734496 adjusts the mesh size in response to changes in the properties of the hydrothermally treated product, making it suitable for the pressure separation device 12. The pressure within the pressure separation device 12 may be adjusted in response to changes in the properties of the hydrothermally treated product, for example, by increasing or decreasing the size of the outlet. Furthermore, unlike the device shown in Figure 2, the pressure separation device 12 may be configured as a single screw press.

[0023] In the pressure separation device 12 of FIG. 2 , the hydrothermally treated product transferred from the adjustment tank 11 of the first facility 2 by the first transfer device 21 is first introduced into a rotary drum screen 12A. The rotary drum screen 12A then separates a portion of the hydrothermally treated liquid from the hydrothermally treated product. The hydrothermally treated product discharged from the rotary drum screen 12A is then introduced into a screw press 12B. Therefore, compared to a case where the rotary drum screen 12A is not provided in the upstream stage (i.e., the pressure separation device 12 is a single screw press), the screw press 12B in the downstream stage pressurizes the hydrothermally treated product, which is less in volume than the total amount of the hydrothermally treated product transferred by the first transfer device 21, and separates it into the hydrothermally treated liquid and the residue. Therefore, the pressure separation device 12 of FIG. 2 can reduce the power required for the screw press 12B (saving electricity). The part of the hydrothermally treated liquid separated by the rotary drum screen 12A and the part of the hydrothermally treated liquid separated by the screw press 12B are both stored in the solubilization tank 13 of the second equipment 3.

[0024] The solubilization tank 13 of the second facility 3 is a device that stores and heats the hydrothermally treated liquid separated in the pressure separation device 12 to solubilize the hydrothermally treated liquid. The heating temperature can be, for example, approximately 40°C to 60°C. By solubilizing the hydrothermally treated liquid in the solubilization tank 13, insoluble solids (suspended solids, hereinafter referred to as "SS") suspended in the hydrothermally treated liquid are converted to solids (dissolved solids, hereinafter referred to as "DS") dissolved in the hydrothermally treated liquid. As a result, the proportion of SS in the total amount of solids (total solids, hereinafter referred to as "TS"; TS = SS + DS) contained in the hydrothermally treated liquid stored in the solubilization tank 13 decreases. Therefore, the solubilization tank 13 can be considered a device that reduces the amount of SS and increases the amount of DS in the stored hydrothermally treated liquid, thereby promoting acid fermentation. In general, a higher amount of DS of organic matter in the TS is desirable for gas production by microorganisms and bacteria. The TS, SS, or DS of the hydrothermally treated liquid stored in the solubilization tank 13 can be measured using a dedicated measuring device (not shown). Furthermore, similar to the adjustment tank 11, the solubilization tank 13 may be provided with a stirring device to stir the hydrothermally treated liquid stored in the solubilization tank 13 and promote solubilization of the hydrothermally treated liquid.

[0025] The second transfer device 22 is a device that returns the hydrothermally treated liquid from the solubilization tank 13 to the adjustment tank 11 of the first facility 2 when the concentration of organic matter contained in the hydrothermally treated liquid stored in the solubilization tank 13 of the second facility 3 is less than a predetermined concentration (e.g., TS is about 10%, DS is about 6%), and transfers the hydrothermally treated liquid from the solubilization tank 13 to the gas generator 14 of the third facility 4 when the predetermined concentration is reached (including when the concentration is substantially equal to or greater than the predetermined concentration. The predetermined concentration may also be a range, for example, TS is about 10% to 12%, DS is about 6% to 8%). The second transfer device 22 may be configured to automatically select either the adjustment tank 11 or the gas generator 14 as the transfer destination based on the measurement results of the aforementioned measurement device, and transfer the hydrothermally treated liquid stored in the solubilization tank 13 to the selected destination. The predetermined concentration is set to a concentration of organic matter suitable for gas generation by microorganisms or bacteria in the gas generator 14 described below. At the predetermined concentration, the pH value of the hydrothermally treated liquid stored in the solubilization tank 13 is acidic, less than 7, and preferably 5 or less.

[0026] Like the first transfer device 21, when the first facility 2 and the second facility 3 are installed close to each other, the second transfer device 22 is preferably a pipeline connected to the adjustment tank 11 of the first facility 2 and the solubilization tank 13 of the second facility 3 and equipped with a pump that pressure-feeds the hydrothermally treated liquid from the solubilization tank 13 to the adjustment tank 11. On the other hand, when the first facility 2 and the second facility 3 are installed far from each other, the second transfer device 22 is preferably a vehicle (e.g., a vacuum truck) equipped with a storage tank or the like. In this case, the hydrothermally treated liquid is transported from the solubilization tank 13 to the adjustment tank 11 by vehicle. In either case, the hydrothermally treated liquid is circulated between the first facility 2 and the second facility 3 by the second transfer device 22.

[0027] Furthermore, when the second equipment 3 and the third equipment 4 are installed close to each other, the second transfer device 22 is preferably a pipeline connected to the solubilization tank 13 of the second equipment 3 and the gas generator 14 of the third equipment 4 and equipped with a pump that pressure-feeds the hydrothermally treated liquid from the solubilization tank 13 to the inlet of the gas generator 14.

[0028] In addition, when the first facility 2, the second facility 3, and the third facility 4 are installed close to each other, the second transfer device 22 may be configured, for example, to include a switching device in the pipeline connecting the solubilization tank 13 of the second facility 3 and the adjustment tank 11 of the first facility 2, and to connect another pipeline branching off from the pipeline to the switching device and the inlet of the gas generator 14 of the third facility 4. As described above, depending on the concentration of organic matter contained in the hydrothermally treated liquid stored in the solubilization tank 13 of the second facility 3, the second transfer device 22 can alternatively select, using the switching device, either the pipeline connecting the solubilization tank 13 of the second facility 3 and the adjustment tank 11 of the first facility 2 or the other pipeline so as to transfer the hydrothermally treated liquid stored in the solubilization tank 13.

[0029] On the other hand, when the second facility 3 and the third facility 4 are installed far from each other, the second transfer device 22 is preferably a vehicle (e.g., a vacuum truck) equipped with a storage tank or the like. In this case, the hydrothermally treated liquid is transported from the solubilization tank 13 to the gas generator 14 by vehicle, and the hydrothermally treated liquid is introduced into the inlet of the gas generator 14. When the first facility 2 and the second facility 3 are installed close to each other and the second facility 3 and the third facility 4 are installed far from each other, the second transfer device 22 may be a pipeline for transferring the hydrothermally treated liquid between the first facility 2 and the second facility 3, or a vehicle for transferring the hydrothermally treated liquid between the second facility 3 and the third facility 4. In other words, the second transfer device 22 may combine the functions of both a pipeline and a vehicle. Similarly, if the first equipment 2 and the second equipment 3 are installed far away from each other and the second equipment 3 and the third equipment 4 are installed close to each other, the second transfer device 22 may be a vehicle for transferring the hydrothermal treatment liquid between the first equipment 2 and the second equipment 3, and a pipeline for transferring the hydrothermal treatment liquid between the second equipment 3 and the third equipment 4.

[0030] The second transfer device 22 returns the hydrothermally treated liquid stored in the solubilization tank 13 of the second facility 3 to the adjustment tank 11 of the first facility 2 until the concentration of organic matter contained in the hydrothermally treated liquid reaches the above-mentioned predetermined concentration. Therefore, the hydrothermally treated product stored in the adjustment tank 11 of the first facility 2 can be humidified, which makes it easier to transfer the hydrothermally treated product by the first transfer device 21 and reduces the power required for the pressure separation device 12 of the second facility 3.

[0031] Furthermore, the hydrothermally treated liquid returned from the solubilization tank 13 of the second facility 3 to the adjustment tank 11 of the first facility 2 has been heated in the solubilization tank 13, and therefore can be poured into the adjustment tank 11 at the heated temperature or while maintaining a temperature higher than room temperature even if it has been cooled slightly by natural heat release or the like. In this case, the returned hydrothermally treated liquid can contribute to adjusting the properties of the hydrothermally treated product by, for example, promoting the solubilization of at least a portion of the hydrothermally treated product stored in the adjustment tank 11.

[0032] Furthermore, in the hydrothermal treatment system 1, multiple hydrothermal treatments are performed sequentially over time. However, even if the proportion of each component in the organic-containing waste hydrothermally treated by the hydrothermal treatment device 10 of the first facility 2 varies significantly with each hydrothermal treatment, resulting in significant variations in the concentration of organic matter contained in the hydrothermally treated liquid obtained from each hydrothermal treatment, the return circulation of the hydrothermally treated liquid between the first facility 2 and the second facility 3 can average the concentration of organic matter contained in the hydrothermally treated liquid stored in the solubilization tank 13. When the concentration of organic matter contained in the hydrothermally treated liquid stored in the solubilization tank 13 reaches a predetermined concentration, the hydrothermally treated liquid of the predetermined concentration is transferred to the gas generator 14 by the second transfer device 22. Therefore, the concentration of organic matter contained in the hydrothermally treated liquid input to the gas generator 14 is substantially constant and has little variation, and the hydrothermally treated liquid contains a large amount of organic matter that contributes to gas generation. Therefore, the gas generator 14 can stably generate gas.

[0033] In a typical gas generator that uses microorganisms or bacteria to generate gas from a hydrothermally treated liquid as a raw material, solubilization and acid fermentation must be performed within the device. However, in the hydrothermal treatment system 1, when the concentration of organic matter contained in the hydrothermally treated liquid stored in the solubilization tank 13 reaches the predetermined concentration, solubilization and acid fermentation in the solubilization tank 13 are already in a state suitable for gas generation. Therefore, the gas generator 14 can omit the solubilization and acid fermentation performed by a typical gas generator, and can generate gas more quickly than the typical gas generator.

[0034] The gas generator 14 of the third facility 4 is a device that generates gas using microorganisms or bacteria using the hydrothermal treatment liquid stored in the solubilization tank 13 of the second facility 3. The gas generator 14 may be any device that generates gas using microorganisms or bacteria using the hydrothermal treatment liquid as a raw material, and may be a methane fermentation device that generates methane gas by methane fermentation, or a device that generates gas such as hydrogen. The gas generator 14 generates gas by heating the hydrothermal treatment liquid.

[0035] The above describes at least the configuration of the hydrothermal treatment system 1. However, the hydrothermal treatment system 1 may further include the following devices and facilities, as shown in FIG.

[0036] The waste liquid treatment device 15 is a device that purifies waste liquid (e.g., digestion liquid) discharged when gas is generated in the gas generator 14 to produce recycled water. The waste liquid treatment device 15 is, for example, a device that performs nitrification and denitrification treatment on the waste liquid, i.e., biological treatment. The recycled water produced by purifying the waste liquid from the gas generator 14 in the waste liquid treatment device 15 can be supplied to the adjustment tank 11 of the first facility 2 through a supply path 19 formed by a pipeline. Immediately after the start of operation of the hydrothermal treatment system 1, no hydrothermally treated liquid is stored in the solubilization tank 13 of the second facility 3, so the hydrothermal treatment system 1 cannot return the hydrothermally treated liquid to the adjustment tank 11, and therefore cannot humidify the hydrothermally treated product stored in the adjustment tank 11 with the hydrothermally treated liquid. Therefore, in this case, the hydrothermal treatment system 1 can humidify the hydrothermally treated product stored in the adjustment tank 11 by supplying recycled water from the waste liquid treatment device 15 to the adjustment tank 11, allowing the first transfer device 21 to smoothly transfer the hydrothermally treated product and the pressurized separation device 12 of the second facility 3 to operate smoothly immediately after the start of operation of the hydrothermal treatment system 1. If the above-mentioned return is not possible, the hydrothermal treatment system 1 can also inject tap water into the adjustment tank 11 to humidify the hydrothermally treated product. However, to improve the cost performance of the hydrothermal treatment system 1, it is desirable to use recycled water rather than tap water.

[0037] The third transfer device 23 is a device that transfers the gas generated in the gas generator 14 of the third equipment 4 to the gas utilization facility 16 described below. When the gas generator 14 and the gas utilization facility 16 are installed close to each other, the third transfer device 23 is preferably a pipeline that connects the gas generator 14 to the gas utilization facility 16 and transfers the gas generated in the gas generator 14 to the gas utilization facility 16. On the other hand, when the gas generator 14 and the gas utilization facility 16 are installed far from each other, the third transfer device 23 is preferably a vehicle (truck) with a bed for carrying gas cylinders or a vehicle equipped with a gas tank. In this case, the gas generated in the gas generator 14 can be filled into a gas cylinder or gas tank and loaded or carried on the vehicle for transportation to the gas utilization facility 16.

[0038] The gas utilization facility 16 is a facility that utilizes the gas generated by the gas generator 14 of the third facility 4. The gas utilization facility 16 is, for example, a power generation plant that generates electricity by generating steam using the heat generated by burning the gas in a boiler and using this steam to turn a steam turbine. The gas utilization facility 16 may be a power generation plant equipped with a gas turbine, a gas engine, or a fuel cell, or a facility that reforms the gas to generate city gas, etc. If the gas utilization facility 16 is a power generation plant equipped with a gas engine, it is generally equipped with a heat recovery device for exhaust gas generated by the gas engine. The heat recovery device can generate hot water from the exhaust gas.

[0039] When the gas utilization facility 16 is a power generation plant that generates power using a steam turbine, and when at least one of the first facility 2 and the second facility 3 and the gas utilization facility 16 are installed adjacent to each other, waste steam, which is high-temperature steam after being used for power generation by the steam turbine of the gas utilization facility 16, can be utilized in the adjacent first facility 2 or second facility 3. For example, when the gas utilization facility 16 equipped with a steam turbine is installed adjacent to the first facility 2, the gas utilization facility 16 and the first facility 2 can be connected by a pipeline, and the waste steam can be transported via the pipeline to the hydrothermal treatment device 10 of the first facility 2 and utilized as the high-temperature, high-pressure steam used by the hydrothermal treatment device 10, or as a part thereof. Furthermore, when the gas utilization facility 16 equipped with a steam turbine is installed adjacent to the second facility 3, the gas utilization facility 16 and the second facility 3 can be connected by a pipeline, and the waste steam can be transported via the pipeline to the solubilization tank 13 of the second facility 3 and utilized to heat the hydrothermally treated liquid stored in the solubilization tank 13. Furthermore, if a gas utilization facility 16 equipped with a steam turbine is installed close to the third equipment 4, the gas utilization facility 16 and the third equipment 4 can be connected by a pipeline, and the wastewater steam can be transported via the pipeline to the gas generation device 14 of the third equipment 4 and used to heat the hydrothermal treatment liquid stored in the gas generation device 14.

[0040] Furthermore, if a gas utilization facility 16 equipped with a gas engine is installed close to the second facility 3, the gas utilization facility 16 and the second facility 3 can be connected by a pipeline, and the hot water generated in the heat recovery device can be transferred via the pipeline to the solubilization tank 13 of the second facility 3 and used to heat the hydrothermally treated liquid stored in the solubilization tank 13. Also, if the gas utilization facility 16 and the third facility 4 are connected by a pipeline, the hot water can be transferred via the pipeline to the gas generator 14 of the third facility 4 and used to heat the hydrothermally treated liquid stored in the gas generator 14.

[0041] In this way, if the gas utilization facility 16 is equipped with a steam turbine, the waste steam discharged from the steam turbine can be used as a heat source within the hydrothermal treatment system 1, and if the gas utilization facility 16 is equipped with a gas engine, the hot water generated by the heat recovery device can be used as a heat source within the hydrothermal treatment system 1, thereby further improving the cost performance of the hydrothermal treatment system 1.

[0042] The fourth transfer device 24 is a device that transfers the residue separated by the pressurized separator 12 of the second facility 3 to the waste incineration facility 17 described below. When the second facility 3 and the waste incineration facility 17 are installed close to each other, the fourth transfer device 24 is preferably a conveyor that connects the residue discharge outlet of the pressurized separator 12 to the waste pit of the waste incineration facility 17 and transfers the residue discharged from the pressurized separator 12 to the waste pit. On the other hand, when the second facility 3 and the waste incineration facility 17 are installed far from each other, the fourth transfer device 24 is preferably a vehicle such as a truck or garbage truck. In this case, the residue discharged from the pressurized separator 12 can be loaded or stored in the bed of the truck or garbage truck and transported to the waste incineration facility 17.

[0043] The waste incineration facility 17 is a facility that incinerates waste in an incinerator and can also incinerate the residue discharged from the pressurized separation device 12 of the second facility 3. The waste incineration facility 17 generates high-temperature, high-pressure steam in a boiler using heat generated in the incinerator, and generates electricity by using this high-temperature, high-pressure steam to turn a steam turbine. If at least one of the first facility 2 and the second facility 3 and the waste incineration facility 17 are installed adjacent to each other, the high-temperature waste steam, which is the high-temperature steam after being used to generate electricity in the steam turbine of the waste incineration facility 17, can be used in the adjacent first facility 2 or second facility 3. For example, if the waste incineration facility 17 is installed adjacent to the first facility 2, the waste incineration facility 17 and the first facility 2 can be connected by a pipeline, and the waste steam can be transported via the pipeline to the hydrothermal treatment device 10 of the first facility 2 and used as or as part of the high-temperature, high-pressure steam used by the hydrothermal treatment device 10. Furthermore, if the waste incineration facility 17 is installed close to the second facility 3, the waste incineration facility 17 and the second facility 3 can be connected by a pipeline, and the wastewater steam can be transferred via the pipeline to the solubilization tank 13 of the second facility 3 and used to heat the hydrothermal treatment liquid stored in the solubilization tank 13. In this way, the wastewater steam from the waste incineration facility 17 can be effectively used as a heat source within the hydrothermal treatment system 1, further improving the cost performance of the hydrothermal treatment system 1.

[0044] The hydrothermal treatment system 1 may be a system that does not include any of the three: (1) waste liquid treatment device 15, (2) third transfer device 23 and gas utilization facility 16, or (3) fourth transfer device 24 and waste incineration facility 17, or a system that includes only one or two of them, or a system that includes all three.

[0045] REFERENCE SIGNS LIST 1 Hydrothermal treatment system 2 First equipment 3 Second equipment 4 Third equipment 10 Hydrothermal treatment device 11 Adjustment tank 12 Pressure separation device 12A Rotary drum screen 12B Screw press 13 Solubilization tank 14 Gas generation device 15 Waste liquid treatment device 16 Gas utilization facility 17 Waste incineration facility 19 Supply line 21 First transfer device 22 Second transfer device 23 Third transfer device 24 Fourth transfer device

Claims

1. A hydrothermal treatment system comprising: a hydrothermal treatment apparatus for hydrothermally reacting organic-containing waste; an adjustment tank for humidifying the hydrothermally reacted hydrothermal treated product; a first transfer device for transferring the hydrothermally treated product humidified in the adjustment tank; a pressure separation device for pressurizing the hydrothermally treated product transferred in the first transfer device to separate it into a hydrothermally treated liquid and a residue; a solubilization tank for storing and heating the hydrothermally treated liquid separated in the pressure separation device; a second transfer device for returning the hydrothermally treated liquid heated and solubilized in the solubilization tank to the adjustment tank; and a gas generator for generating gas using the hydrothermally treated liquid stored in the solubilization tank, wherein the second transfer device returns the hydrothermally treated liquid to the adjustment tank when the concentration of organic matter contained in the hydrothermally treated liquid stored in the solubilization tank is less than a predetermined concentration that is a concentration of organic matter suitable for gas generation by microorganisms or bacteria, and transfers the hydrothermally treated liquid to the gas generator when the concentration of the organic matter is equal to or greater than the predetermined concentration.

2. The hydrothermal treatment system according to claim 1, further comprising a waste liquid treatment device that produces recycled water from the waste liquid discharged by the gas generation device, and supplies the recycled water produced by the waste liquid treatment device to the adjustment tank.

3. The hydrothermal treatment system according to claim 2, further comprising: a third transfer device that transfers the gas generated by the gas generator; and a gas utilization facility that utilizes the gas transferred by the third transfer device.

4. The hydrothermal treatment system according to claim 3, further comprising: a fourth transfer device for transferring the residue separated by the pressurized separation device; and a waste incineration facility for incinerating the residue transferred by the fourth transfer device.

5. A hydrothermal treatment system as described in claim 4, wherein at least one of the gas utilization facility and the waste incineration facility is equipped with a steam turbine, and the steam used for power generation in the steam turbine is supplied to at least one of the hydrothermal treatment device and the solubilization tank.

6. The hydrothermal treatment system described in claim 5, wherein when the hydrothermal treatment device and the adjustment tank, and the pressurized separation device and the solubilization tank are installed close to each other, the first transfer device is a pipeline equipped with a fracturing pump, and the second transfer device is a pipeline equipped with a pump; and when the hydrothermal treatment device and the adjustment tank, and the pressurized separation device and the solubilization tank are installed far from each other, the first transfer device and the second transfer device are both automobiles.

7. The hydrothermal treatment system described in claim 6, wherein the third transfer device is a pipeline when the gas generation device and the gas utilization facility are installed close to each other, the third transfer device is a vehicle when the gas generation device and the gas utilization facility are installed far from each other, the fourth transfer device is a conveyor when the waste incineration facility, the pressurized separation device and the solubilization tank are installed close to each other, and the fourth transfer device is a vehicle when the waste incineration facility, the pressurized separation device and the solubilization tank are installed far from each other.

8. A hydrothermal treatment system according to any one of claims 1 to 7, wherein the pressurized separation device is provided with a rotary drum screen in the front stage and a screw press in the rear stage, and the hydrothermal treatment liquid separated by the rotary drum screen and the hydrothermal treatment liquid separated by the screw press are stored in the solubilization tank.