KR20140002786A - Storage facility for waste-derived solid fuel and storage method therefor - Google Patents

Abstract

Storage facilities and storage to enable storage of solid waste-derived fuels (eg, RDF or biomass waste-derived solid fuels) under physically easy fermentation conditions, even under high temperature and high humidity environments where fermentation is more likely to be facilitated. Suggest a method. The waste-derived solid fuel is anaerobic fermented in the fermentation tank 52, and the biogas produced by the fermentation is introduced into the primary storage tank 53 (biogas storage tank), and then compressed and cooled to form the secondary storage tank 54 (bio). Gas storage tank). The biogas stored in the secondary storage tank 54 is sent to the boiler 61 of the power generation section 6 to be used as fuel or auxiliary fuel. Fermentation residues of the fuel are removed to reuse the fuel as a raw material of the fuel.

Description

STORAGE FACILITY FOR WASTE-DERIVED SOLID FUEL AND STORAGE METHOD THEREFOR}

The present invention is a long-term storage of waste-derived solid fuel (e.g., waste solidification fuel or biomass waste-derived solid fuel) that is easily fermented and decayed, and has a property of generating odor or flammable gas in the process. It relates to a technique for doing.

Urban waste, commonly referred to as 'garbage' (hereafter referred to as 'MSW'), includes solid waste from households, private companies (office buildings, retail stores, wholesalers, restaurants, etc.). ) And solid waste from public facilities (library, school, hospital, prison, etc.). Conventionally, MSW is collected and separated into combustible waste, recycled waste, metal waste, etc., among which combustible waste is incinerated. Recently, from the standpoint of environmental problems such as dioxine produced by burning waste and effective use of waste resources, waste solidification fuels (MSF) from MSW (hereinafter referred to as 'Refuse Derived Fuel') ) 'Is manufactured. RDF is used as an auxiliary fuel for power generation facilities, as a boiler fuel for hot water in an area, and as an auxiliary fuel for heating sources such as heating furnaces used in various factories. In general, RDF is classified into various kinds (seven kinds in ASTM) from its shape and characteristics. Among them, fluff-shaped RDF (hereinafter referred to as "fluff RDF") and pellet-shaped RDF (hereinafter referred to as "pellet RDF") are widely used. ) ').

10A is a diagram illustrating a general manufacturing process of pellet RDF. As shown in this figure, the collected MSW in the production of pellet RDF is first ground in a mill, dried until it is below a predetermined amount of moisture in a drying facility, the non-combustibles are sorted out, and suitable for the molding process in the second mill. To smaller dimensions. In addition, the metals mixed in the MSW and other foreign matters which are not suitable as fuel are selectively removed during the process. In this way, the MSW, which has been reduced to a dimension suitable for molding, is mixed with a fermentation inhibitor mainly composed of alkaline compounds (such as slaked lime) in order to prevent methane gas generation by fermentation, heat generation and fermentation by microorganisms during RDF storage. In order to compression molding in the shape of a pellet machine. The pellet RDF prepared by the above process generally has a rigid cylindrical shape having a diameter of 10 to 50 mm and a length of 10 to 100 mm, a volume specific gravity of about 0.6 ton / m 3, and a low calorific value of about 4,500 kcal / kg.

 (B) is a figure which shows the general manufacturing process of fluff RDF. As shown in the figure, in the manufacture of fluff RDF, the collected MSW is first milled in the mill, and non-combustibles and foreign matter are selectively removed and secondly milled in the mill until a prescribed dimension is obtained. In addition, metals collected in the MSW and other foreign matters that are not suitable as fuels are selectively removed during the process. In addition, if the amount of moisture in the collected MSW is excessive, a drying process is added upstream or downstream of the secondary grinding process. The fluff RDF produced by the above process generally has a flat shape of 50 to 150 mm square, the volume specific gravity varies depending on the amount of water contained, but is about 0.1 to 0.2 ton / m 3, and the lower calorific value is about 3,500 kcal / kg. to be. In the manufacturing process of fluff RDF, each process of a drying process and a molding process is abbreviate | omitted among the manufacturing processes of pellet RDF. For this reason, in the manufacture of fluff RDF, a drying furnace and its fuel, a fermentation inhibitor and a molding machine, and its power are unnecessary. As a result, the manufacturing cost of fluff RDF is cheap compared with pellet RDF. However, fluff RDF is not suitable for long-distance transportation due to its high volume, and omits the adjustment of moisture and the addition of fermentation inhibitors to prevent RDF fermentation during storage. It is an industry recommendation that storage should be avoided.

11 is a conceptual diagram of an overall RDF combustion power generation system from conventional MSW collection to RDF manufacturing and RDF combustion power generation. As shown in the figure, the collected MSW is brought into the RDF manufacturing facility 101, where an RDF is produced from the MSW. The manufactured RDF is carried in the accommodation facility 102 and put into the boiler 61 of the power generation facility 103. In the power generation equipment 103, the boiler 61 burns RDF as fuel or auxiliary fuel, and power generation is performed by rotating the steam turbine power generation equipment 62 with steam of high temperature and high pressure from which the combustion heat is recovered.

In Europe, the main component of the MSW is based on a relatively low average temperature and a dry climate, in addition to a strict collection of mainstream commodities (such as vegetable debris and food residues) and general combustible waste. Is combustible waste such as cloth, plastics and wood. Therefore, the moisture contained in the MSW, which is the raw material of RDF, is less than that of other regions where mixed mussels are mixed. In addition, the RDF manufacturing facility 101, the receiving facility 102, and the power generation facility 103 of the RDF combustion power generation system are adjacent to or close to each other, and the manufactured RDF is immediately stored for a long time without being stored for a long time. Burns). Therefore, long-distance transport and long-term storage of RDF are unnecessary. For this reason, fluff RDF is employed in these areas.

In addition, in Europe, a situation in which the fluff RDF must be stored in the receiving facility 102 for a long time in order to check and maintain the power generation facility 103 may occur. Because fluff RDF has a low volume specific gravity, it requires a vast storage location to store as it is. Thus, by packing the fluff RDF with a vinyl sheet or the like, the fluff RDF is stored in a state of easy storage and transport with a slight increase in bulk specific gravity. However, contact between the RDF and the outside air is inevitable with the packaged vinyl sheet, and organic matter in the RDF may be aerobic fermented inside the package due to the moisture contained in the RDF. Methane and ammonia generated by the fermentation of RDF may cause fire or odor. The side-by-side storage of RDF packaged on a planar open site prevents the retention of methane or ammonia gas, but odor problems around the storage site are inevitable.

In most parts of Japan, separate collection of mainstream compost and combustible waste is not carried out. Therefore, moisture contained in MSW, which is a raw material of RDF, is higher than that of European MSW. In addition, the basic policy of RDF of MSW in Japan is to RDF and localize MSW of local governments scattered in a large area into one place to collectively dispose of waste and to make effective use of energy by heat recovery. Because of this, many RDF manufacturing facilities 101 and receiving facilities 102 are remote, short distance, and require transport of RDF. Moreover, one set of accommodating equipment 102 and the power generating equipment 103 are provided with respect to the some RDF manufacturing equipment 101, and it is transported from the several RDF manufacturing equipment 101 by one accommodation equipment 102. There is a need for long-term storage of the entire RDF. For this reason, pellet RDF suitable for transportation and long-term storage is the mainstream in Japan.

Pellet RDF is suitable for long term storage compared to fluff RDF, but because it is a fuel that easily ferments, a stringent storage method is required to prevent fermentation and ignition of the RDF. Therefore, the technique for long term storage of pellet RDF is proposed conventionally (for example, patent document 1, 2, 3). In patent document 1, the solid fuel storage tank for long term storage of pellet RDF is shown. The solid fuel reservoir is configured to circulate air in the reservoir and to circulate the solid fuel in order to suppress the heat storage in the reservoir to prevent spontaneous ignition. In addition, the reservoir is equipped with a carbon monoxide detector, a temperature sensor and a watering nozzle to detect spontaneous ignition and to extinguish the fire immediately upon ignition.

Patent Literature 2 shows a solid fuel cooling tower configured to fill a pellet RDF in a cooling chamber formed in a vertical hopper shape and flow a cooling gas as if penetrating the RDF packed bed. In addition, Patent Document 3 collects gas from the air gap of the RDF stored in the open pit (open pit), and detects the heat generated by measuring the composition and temperature of the collected gas, the waste configured to inject nitrogen gas into the heat generated portion Solid fuel storage devices are shown.

Japanese Patent Laid-Open No. 2003-206010 Japanese Patent Laid-Open No. 2002-69469 Japanese Patent Laid-Open No. 2007-16174

In recent years, the treatment of MSW has become a major environmental problem in Far East Asia (Korea, China, etc. except Japan) and Southeast Asia. Some of these regions have already begun planning to make use of energy by making MSW into RDF. These areas are common in that the MSWs collected contain a large amount of main streams that are not suitable for fluff RDF, and the weather conditions are high temperature and high humidity due to the incomplete disposal of foods and the food and dietary habits. Even under such conditions, there is a need to establish a system for producing fluff RDF from the collected MSW and generating power from the RDF as a fuel, in view of the RDF manufacturing facility and the RDF manufacturing cost. However, a method of safely and long-term storage of fluff RDF prepared from MSW containing a large amount of moisture and easily fermented mussels in a high temperature and high humidity environment where fermentation is easy to be promoted without adding an alkaline compound that inhibits fermentation It is not established. The packing and storage method of fluff RDF in Europe mentioned above is established under careful supervision in addition to the low moisture content of fluff RDF and relatively dry climate, and the high moisture content and high temperature and high humidity of fluff RDF. It is not proven to hold under conditions. In addition, the storage method of RDF proposed by patent document 1-patent document 3 is all made into pellet RDF.

The problem regarding long term storage, such as fluff RDF, also has a solid fuel derived from biomass wastes produced from biomass wastes. Here, the term "biomass waste-derived solid fuel" means that the biomass waste is made into a form suitable for the requirements of a combustion facility by removing foreign matter, crushing or cutting. Biomass-based wastes also contain large amounts of water and many organic substances suitable for fermentation. The countries that produce large quantities of biomass waste are Southeast Asia under high temperature and high humidity conditions. 10C is a diagram illustrating a general manufacturing process of the solid fuel derived from biomass wastes. As shown in the figure, in the manufacture of biomass waste-derived solid fuels, the collected biomass waste is sorted out of large incombustibles, firstly pulverized in a mill, and small incombustibles are sorted out, and have dimensions suitable for combustion. Secondary grinding. Solid oils derived from biomass wastes, oil palm biomass (oil palm stems, leaves, oil palm husks, etc.), sugar cane biomass (sugarcane residue), coconut biomass (coconut) Manufactured from biomass wastes such as salty residues) and jatropha-based biomass (leaves, shells, etc.) of Jatropha are particularly easy to ferment because they contain large amounts of organic matter and moisture, and are fast to ferment. . Therefore, long-term storage problems such as fluff RDF also occur in power generation facilities using solid fuel derived from biomass waste.

The present invention has been made to solve the above problems, and the fermentation-derived solid fuel (for example, RDF or biomass-based waste-derived solid fuel) under conditions that are easily physically fermented is more easily promoted. An object of the present invention is to propose a storage facility and a storage method for storing under high temperature and high humidity.

The storage facility for waste-derived solid fuel according to the present invention is a storage facility for storing waste-derived solid fuel before combustion in a combustion plant, and a fermentation tank for anaerobic fermentation of the waste-derived solid fuel, and the waste-derived solid. A biogas storage tank for storing biogas generated by anaerobic fermentation of fuel; a first flow path for sending the biogas from the fermentation tank to the biogas storage tank; and supplying the biogas to the combustion facility from the biogas storage tank. It is provided with a supply path.

In addition, the storage method of the waste-derived solid fuel according to the present invention is a method of storing the waste-derived solid fuel easy to ferment before combustion in a combustion facility, the step of anaerobic fermentation of the waste-derived solid fuel in an anaerobic fermenter, and the waste And storing the biogas generated by the anaerobic fermentation of the derived solid fuel in a biogas storage tank.

According to the storage facility and storage method of the waste-derived solid fuel, the waste-derived solid fuel is easily changed into a form of biogas and its fermentation residues to be stored. Since most of the organic matter in the waste-derived solid fuel is changed to biogas due to the fermentation of the waste-derived solid fuel, the amount of solids is reduced by the amount of the fermented organic matter in the waste-derived solid fuel. In short, the fermentation residue is reduced in comparison with the original waste-derived solid fuel, so that the space for solid storage can be reduced. In addition, since most of the organic matter contained in the waste-derived solid fuel is converted into biogas by anaerobic fermentation in the fermentation tank, and the remaining amount of organic matter contained in the fermentation residue is reduced, handling and storage of the fermentation residue are waste-derived solids. Easy to compare with the fuel itself. In addition, since biogas is a gas and does not change with time, it is easy to store compared with the state of waste-derived solid fuel. In addition, the fuel storage facility and the fuel storage method can store the waste-derived solid fuel, which is easy to ferment in a dry environment or a high temperature and high humidity environment, and can stably store the waste-derived solid fuel regardless of the storage environment.

In the waste storage facility of the solid fuel, the biogas storage tank includes a primary storage tank through which the biogas is sent from the fermentation tank through the first flow passage, and a secondary storage tank connected to the primary storage tank and a second flow passage, It is preferable to include a compressor for compressing and sending the biogas from the primary reservoir to the secondary reservoir in the second flow path, and a cooler for cooling the biogas compressed by the compressor in the second flow path. Similarly, in the method for storing the waste-derived solid fuel, the storing of the biogas in the biogas storage tank may include receiving biogas from the fermentation tank in a primary storage tank, and storing the biogas from the primary storage tank in the secondary storage tank. Compressing and sending gas by compressing the gas, cooling the compressed biogas, and storing the compressed biogas in the secondary storage tank.

Since biogas is a gas, unlike a solid waste derived solid fuel, it can be reduced by compression. Therefore, according to the storage facility and storage method of the waste-derived solid fuel, since the biogas is stored in a tank-shaped storage facility in a compressed state, it is possible to reduce the planar area required for storing the biogas. In addition, by adjusting the pressure of the biogas, it is possible to change the size of the space required for storing the same amount of biogas.

The storage facility of the waste-derived solid fuel, comprising: water removal means for removing water contained in the fermentation residue of the waste-derived solid fuel and water contained in the fermentation residue of the waste-derived solid fuel discharged from the fermentation tank. good. Similarly, the method of storing the waste-derived solid fuel, the method comprising the step of removing the water contained in the fermentation residue of the waste-derived solid fuel and the water which is a fermentation complete residue of the waste-derived solid fuel discharged from the fermentation tank. good.

According to the storage facility and storage method of the waste-derived solid fuel, since the fermentation residues are further reduced by the removal of moisture, it is possible to further reduce the space for the storage of the fermentation residues. In addition, by removing moisture from the fermentation residue, the fermentation residue from which the moisture has been removed can be reused as a raw material of the waste-derived solid fuel.

In the storage of the waste-derived solid fuel, the oxygen concentration sensor for detecting the oxygen concentration of the effluent gas flowing out of the fermenter to the first flow path, the methane concentration sensor for detecting the methane concentration of the effluent gas, According to the oxygen concentration and the methane concentration, the oxygen and methane gas mixing ratio of the effluent gas is preferably opened when the first control valve for communicating with the first flow path and the biogas storage tank. Similarly, in the method for storing the waste-derived solid fuel, in the step of storing the biogas in a biogas storage tank, the oxygen concentration and the methane concentration of the effluent gas flowing out of the fermentation tank containing the biogas is sensed, According to the detection result, it is preferable to store in the biogas storage tank that the mixing ratio of the oxygen and methane gas in the effluent gas is outside the combustion range.

According to the fuel storage facility or the fuel storage method, only those suitable for compression in the effluent gas from the fermentation tank are sent to the biogas storage tank as biogas, thereby increasing the safety at the time of biogas storage and the safety at the time of biogas reuse.

In the storage of the waste-derived solid fuel, the oxygen of the effluent gas in accordance with the air discharge passage for communicating the inside of the fermenter and the atmosphere, the oxygen concentration detected by the oxygen concentration detector and the methane concentration detected by the methane concentration detector It is preferred to have an atmospheric release valve which opens when the methane gas mixing ratio is within the combustion range and releases the effluent gas to the atmosphere through the atmospheric release passage. Or, in the storage of the waste-derived solid fuel, the effluent gas according to the preliminary storage tank connected through the fermentation tank and the third flow path, the oxygen concentration detected by the oxygen concentration detector and the methane concentration detected by the methane concentration detector It is preferable to have a second control valve which opens when the oxygen and methane gas mixing ratio is within the combustion range to communicate the third flow path with the preliminary reservoir.

Similarly, in the method of storing the waste-derived solid fuel, in the step of storing the biogas in a biogas storage tank, the mixing ratio of the oxygen and methane gas in the effluent gas depends on the oxygen concentration and the methane concentration of the effluent gas. It is advisable to release to air what is in the combustion range. Alternatively, in the method of storing the waste-derived solid fuel, in the step of storing the biogas in a biogas storage tank, the mixing ratio of the oxygen and methane gas in the effluent gas is burned according to the oxygen concentration and the methane concentration of the effluent gas. It is better to store the one in the range in a reserve reservoir different from the biogas reservoir.

According to the fuel storage facility or the fuel storage method, if only the embers of the effluent gas from the fermentation tank has the possibility of burning without receiving the combustion oxygen from the outside is stored in the preliminary storage tank not released or compressed biogas storage biogas storage Safety at the time of use and safety at the time of biogas reuse can be improved.

In the storage facility for the waste-derived solid fuel, it is preferable that the supply passage has a path for supplying the biogas stored in the biogas storage tank as the fuel for starting the combustion facility to the combustion facility. Similarly, in the method for storing waste-derived solid fuel, the method may further include supplying the biogas stored in the biogas storage tank as the fuel for starting the combustion facility to the combustion facility.

According to the fuel storage facility or fuel storage method, biogas can be effectively used as fuel or auxiliary fuel of a combustion facility.

In the storage facility of the waste-derived solid fuel, the supply path is a path for supplying the biogas stored in the biogas storage tank to at least one of the primary combustion air supply path and the secondary combustion air supply path of the combustion facility. It is good to have. Here, the supply passage is provided with adjusting means for adjusting the supply amount of the biogas such that the biogas supplied to the combustion facility is mixed with the primary combustion air or secondary combustion air of the combustion facility at a mixing ratio outside the combustion range. It is good.

Similarly, the method for storing waste-derived solid fuel further comprises supplying the biogas stored in the biogas storage tank to at least one of a primary combustion air supply path and a secondary combustion air supply path of the combustion installation. Good to do. Here, it is preferable to adjust the supply amount of the biogas such that the biogas supplied to the combustion facility is mixed with the primary combustion air or secondary combustion air of the combustion facility at a mixing ratio outside the combustion range.

According to the fuel storage facility or the fuel storage method, biogas can be effectively used as fuel.

The waste-derived solid fuel may be a waste solidification fuel produced from general waste. Alternatively, the waste-derived solid fuel may be a biomass waste-derived solid fuel manufactured from biomass-based waste.

According to the present invention, the waste-derived solid fuel is easily changed into a form of biogas that can be applied by compression and the fermentation residue after the organic matter in the waste-derived solid fuel has been gasified by fermentation. Biogas no longer ferments. Organic matter contained in the fermentation residue is significantly reduced compared to the state of the original waste-derived solid fuel, so that it can be stored under high temperature and high humidity conditions where fermentation is more likely to be promoted. Thus, management of storage becomes easy compared with when storing waste-derived solid fuel itself. In addition, since the waste-derived solid fuel is fermented, the amount of solids is reduced and thus the space required for solid storage can be reduced.

1 is an overall conceptual diagram of an RDF combustion power generation system including a fuel storage facility according to an embodiment of the present invention.
2 is a conceptual diagram illustrating a configuration of a fuel manufacturing unit.
3 is a conceptual diagram showing a configuration of an upstream side of the primary storage tank of the fuel long-term storage unit.
4 is a conceptual diagram showing a configuration of a downstream side of the primary storage tank of the fuel long-term storage unit.
5 is a block diagram showing a control configuration of a fuel long-term storage unit.
6 is a view for explaining the combustion range of methane.
It is a flowchart which shows the control flow in the initial stage of RDF input of a fermenter control part.
Fig. 8 is a conceptual diagram showing the configuration on the upstream side of the primary storage tank of the fuel long term storage unit according to the modification. Fig.
9 is a conceptual diagram showing a configuration of a downstream side of the primary storage tank of the fuel long-term storage unit according to the modification.
(A) is a figure which shows the general manufacturing process of pellet RDF, FIG. 10 (b) is a figure which shows the general manufacturing process of fluff RDF, and FIG. 10 (c) is a solid derived from a biomass waste material. It is a figure which shows the general manufacturing process of fuel.
11 is an overall conceptual diagram of an RDF combustion power generation system from conventional MSW collection to buta RDF production and RDF combustion power generation.

The storage facility for waste-derived solid fuels according to the present invention (hereinafter also referred to simply as 'fuel storage facility') includes a large amount of organic-derived waste-derived fuels that are easily fermented (for example, a few). For weeks to months). Hereinafter, an RDF combustion power generation system using a fuel storage system according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 is an overall conceptual diagram of an RDF combustion power generation system including a fuel storage facility according to an embodiment of the present invention, in which arrows indicate the flow of materials. In addition, in the same drawing, the description of the detailed auxiliary apparatus which is not directly related to the invention is omitted.

As shown in FIG. 1, the RDF combustion power generation system 1 mainly consists of the fuel manufacturing part 3, the fuel temporary storage part 4, the fuel long-term storage part 5, and the power generation part 6. As shown in FIG. This RDF combustion power generation system 1 is a waste solidified fuel (hereinafter referred to as 'Refuse Derived Fuel') from urban waste (hereinafter referred to as 'Municipal Solid Waste'), which is a waste discharged from ordinary households. And power generation using heat generated by the RDF combustion. In the RDF combustion power generation system 1, the fuel temporary storage unit 4 and the fuel organ storage unit 5 are adjacent to the power generation unit 6. However, the fuel manufacturing unit 3 may be adjacent to or separated from the power generation unit 6. Moreover, the some fuel manufacturing part 3 may exist with respect to one power generation part 6. Next, each part which comprises the RDF combustion power generation system 1 is demonstrated in detail.

(Fuel manufacturing department (3))

The fuel production section 3 is equipped with equipment for manufacturing fluff RDF (fluff-shaped RDF) from MSW. 2 is a conceptual diagram of the fuel production section 3, and arrows in the figure indicate the flow of materials. As shown in the same figure, the fuel manufacturing part 3 is mainly equipped with the MSW storage pit 31, the primary grinder 32, the sorting machine 33, and the secondary grinder 34. As shown in FIG. The MSW storage pit 31 is for temporarily storing the collected MSW. This MSW storage pit 31 has a capacity to accommodate, for example, MSW for up to 5 days. The primary grinder 32 is to tear plastic bags or cloth-like materials in MSW or to crush large solids in order to remove the foreign matter or non-combustibles from the sorter 33. The sorter 33 is for sorting out and removing incombustibles and the like from the MSW. These incombustibles include pieces of stone or concrete, metals, and the like. The secondary grinder 34 is for pulverizing smaller until the non-combustibles and the like have MSW screened and removed to the required dimensions.

In the fuel manufacturing section 3 of the above configuration, the collected MSW is first loaded into the MSW storage pit 31 and temporarily stored. The MSW stored in the MSW storage pit 31 is sequentially introduced into the primary grinder 32 and roughly ground. In the primary milled MSW, the non-combustibles are sorted out in the sorter 33 and input to the secondary mill 34. The MSW made of combustible material introduced into the secondary mill 34 is crushed smaller in the secondary mill 34 to become fluff RDF (fluff-shaped RDF). The RDF thus produced has a flat plate shape of 50 to 150 mm square.

(Fuel temporary storage (4))

The fuel temporary storage section 4 has a fuel reservoir 36 for storing the RDF. The RDF produced in the fuel production section 3 is carried in the fuel reservoir 36 and is temporarily stored there. The period during which the RDF is stored in the fuel reservoir 36 takes into account the volume of the fuel reservoir 36 and the safety aspects during storage, and is generally several days, or at most seven days. The RDF stored in the fuel reservoir 36 is sent to the power generation unit 6 when the power generation unit 6 is operated. In addition, a period in which the power storage unit 6 can be stored may be stored in the fuel reservoir 36, for example, when the total heat of the manufactured RDF exceeds the heat value of the optimal operation base of the power generation unit 6. When there is a surplus RDF to be stored in excess, the RDF stored in the fuel reservoir 36 corresponding to the surplus is sent to the fuel organ storage unit 5.

(Generation part 6)

The power generation unit 6 is a power generation equipment group for generating power by burning RDF. The power generation unit 6 is mainly included in the boiler 61 which is a combustion facility of RDF, the steam turbine power generation facility 62 to which high-pressure, high-temperature steam is supplied from the boiler 61, and the exhaust gas from the boiler 61. An exhaust gas treatment facility 63 for removing the harmful substances is provided. In addition, although the boiler 61 of the power generation part 6 which concerns on a present Example is an RDF combustion boiler, it may be a coal-fired boiler instead. In this case, RDF is used as an auxiliary fuel of the coal boiler.

The RDF stored in the fuel storage 36 of the fuel temporary storage part 4 is injected into the combustion chamber 61a of the boiler 61. In the combustion chamber 61a of the boiler 61, the heat generated by the combustion of the RDF is recovered by the heat recovery water and the superheated steam flowing through the heat recovery unit 61b. The heat recovery unit 61b and the steam turbine power generation facility 62 are connected to a steam discharge path 68 formed of a pipe or the like. The steam which has recovered the heat of combustion of the RDF and has become high temperature and high pressure is sent to the steam turbine power generation facility 62 through the steam discharge path 68. In the steam turbine power generation facility 62, power generation is performed by a generator that rotates a turbine with steam and converts the rotational force into electric power.

The primary combustion air supply path 65, the secondary combustion air supply path 66, the starting fuel supply path 67, and the exhaust path 69 are connected to the combustion chamber 61a of the boiler 61. The primary combustion air supply path 65 is composed of a pipe and a blower that connect the combustion chamber 61a of the boiler 61 to the primary combustion air source (external), and the primary combustion air supply path 65 through the primary combustion air supply path 65. Primary combustion air for combustion is supplied from the air source to the combustion chamber 61a of the boiler 61. The secondary combustion air supply path 66 is composed of a pipe and a blower connecting the inside of the combustion chamber of the boiler 61 and the secondary combustion air source (external), and the secondary combustion air supply path 66 of the boiler 61 through the secondary combustion air supply path 66. Secondary combustion air for combustion is supplied to the combustion chamber 61a. The starting fuel supply passage 67 is composed of a pipe connecting the inside of the combustion chamber of the boiler 61 and a starting fuel source, and at the start of the boiler 61, the starting fuel supply passage 67 is connected to the boiler ( The fuel for starting a boiler is supplied to the combustion chamber 61a of 61. The exhaust passage 69 is constituted by a pipe connecting the combustion chamber 61a of the boiler 61 and the exhaust gas treatment facility 63, and the like. The exhaust gas generated in the combustion chamber 61a of the boiler 61 is sent to the waste gas processing facility 63 through the exhaust path 69. In the exhaust gas treatment facility 63, the harmful substances contained in the exhaust gas of the boiler 61 are removed and then discharged to the outside through the chimney.

(Fuel long-term storage part (5))

Next, the fuel organ storage unit 5 will be described in detail. The fuel long-term storage unit 5 is a group of equipment for storing the RDF beyond the storage period in the fuel temporary storage unit 4. In the fuel long-term storage unit 5, the RDF is stored in a reduced and reduced state of biogas and fermentation residue. 3 is a conceptual diagram showing a configuration of an upstream side of the primary storage tank of the fuel long-term storage unit, and FIG. 4 is a conceptual diagram illustrating a configuration of a downstream side of the primary storage tank of the fuel long-term storage unit. In Figures 3 and 4 the flow of material is indicated by arrows. 5 is a block diagram showing a control configuration of the fuel organ storage unit 5. As shown in FIG. 3, FIG. 4, the fuel long-term storage part 5 mainly contains the input apparatus 51, the fermentation tank 52, the primary storage tank 53, the secondary storage tank 54, and the residue discharge apparatus 55. As shown in FIG. ), A compressor 57, and a biogas supply facility 59.

The input device 51 is for injecting RDF into the fermentation tank 52 from the fuel reservoir 36 of the fuel temporary storage part 4. The input device 51 includes a fuel input tank 11 provided between the fuel reservoir 36 and the input port 18 of the fermentation tank 52. The fuel reservoir 36 and the fuel injection tank 11 and between the fuel injection tank 11 and the fermentation tank 52 are connected through various conveyors or piping. Between the fuel reservoir 36 and the fuel injection tank 11, the 1st injection valve 12 which divides this space and regulates the RDF movement from the fuel reservoir 36 to the fuel injection tank 11 is provided. . Between the fuel injection tank 11 and the fermentation tank 52, the 2nd injection valve 13 which divides this space and regulates the RDF movement from the fuel injection tank 11 to the fermentation tank 52 is provided. In addition, an inert gas supply path 15 for supplying an inert gas from the inert gas source 14 to the fuel input tank 11 is connected to the fuel input tank 11, and to the inert gas supply path 15. An assist gas supply valve 16a is provided. In addition, an inert gas discharge passage 11a for discharging the inert gas as the assist gas from the fuel injection tank 11 is provided in the fuel injection tank 11, and the assist gas discharge path 11a is discharged. The valve 16b is provided. As shown in FIG. 5, opening / closing operations of the first input valve 12, the second input valve 13, the assist gas supply valve 16a, and the assist gas discharge valve 16b are performed by the input device controller 17. It is controlled.

Next, operation | movement of the input device 51 of the said structure is demonstrated. The input device control unit 17 receives an input instruction including an RDF input amount input through an operation panel (not shown), and opens the first input valve 12 by a time corresponding to the RDF input amount. The RDF then moves from the fuel reservoir 36 to the fuel injection tank 11. Subsequently, the input device control unit 17 opens the second input valve 13. As a result, the RDF in the fuel injection tank 11 falls to the fermentation tank 52 at its own weight. Here, the input device control unit 17 opens the assist gas supply valve 16a and the assist gas discharge valve 16b and supplies the RDF by the inert gas supplied to the fuel injection tank 11 through the inert gas supply passage 15. It may be controlled to forcibly push the fermenter 52. When the input of the RDF into the fermentation tank 52 is completed, the input device control unit 17 closes the second input valve 13, the assist gas supply valve 16a, and the assist gas discharge valve 16b. According to the operation | movement of the above-mentioned input device 51, the RDF of the indicated RDF input amount is thrown into the fermentation tank 52, and the fuel injection tank 11 after RDF addition is almost closed.

Fermenter 52 is an anaerobic fermenter that anaerobes the RDF over about 15-20 days in an anaerobic atmosphere. The fermentation tank 52 is provided with a moving device 20 for moving the RDF from the input side 52a with the inlet 18 to the discharge side 52b with the outlet 19. The moving device 20 does not matter in shape as long as it can move the RDF from the input side 52a to the discharge side 52b, but FIG. 3 illustrates the moving device 20 with the rotary vanes. The moving device 20 includes a plurality of rotary vanes arranged in the conveying direction of the RDF from the input side 52a to the discharge side 52b and a rotary vane driving unit for rotating the rotary vane. When the rotary vane rotates in accordance with the driving of the rotary vane drive unit, the RDF dropped to the injection side 52a of the fermentation tank 52 is sequentially sent to the discharge side 52b by a plurality of rotating rotary vanes. The moving speed and the moving amount of the RDF can be controlled by adjusting the rotating speed and the rotating frequency of the rotary vane.

In addition, the biogas discharge port 21 is opened in the upper part of the discharge side 52b of the fermentation tank 52. The biogas discharge port 21 is connected to the primary storage tank 53 through the biogas first flow path 22. The biogas first flow passage 22 includes a pressure sensor 71 for detecting the pressure of the biogas passing through the biogas first flow passage 22, and an oxygen concentration detector 78 for detecting the oxygen concentration, as well as methane concentration. A methane concentration detector 79 for sensing is installed. Further, a first inflow control valve 23 for opening and closing the biogas first flow passage 22 is provided on the downstream side of the detectors 71, 78, and 79 of the biogas first flow passage 22. In accordance with the opening and closing of the first inflow control valve 23, the communication and blocking of the fermentation tank 52 and the primary storage tank 53 are switched.

Atmosphere discharge downstream of the detectors 71, 78, 79 of the biogas first flow passage 22 and upstream of the first inlet control valve 23 to communicate the inside and outside (atmosphere) of the fermentation tank 52. The furnace 24 branches off from the biogas first flow passage 22. The air discharge valve 24 is provided with an air discharge valve 25. In accordance with the opening and closing of the atmospheric release valve 25 and the opening and closing of the first inflow control valve 23, communication and interruption between the inside and the outside of the fermentation tank 52 through the atmospheric release passage 24 are switched.

In addition, an inert gas supply port 26 is provided on the injection side 52a of the fermentation tank 52. The inert gas supply port 26 is connected through the inert gas source 14 and the inert gas supply path 15. An inert gas master valve 27 is provided in the inert gas supply passage 15. The inert gas master valve 27 is opened together with the atmospheric release valve 25 when the air in the fermentation tank 52 is replaced with an inert gas. Accordingly, the inert gas is supplied into the fermentation tank 52 through the inert gas supply port 26 and the air in the fermentation tank 52 is discharged through the air discharge passage 24, whereby the air in the fermentation tank 52 is inert gas. Is replaced by. In addition, a water supply device 29 for supplying water to the fermentation tank 52 is provided on the input side 52a of the fermentation tank 52 to make the amount of water of the RDF injected into the fermentation tank 52 suitable for anaerobic fermentation. have. The water supply device 29 is provided with a water supply pipe 29b connecting the water source 29a and the fermentation tank 52, and a water supply control valve installed in the water supply pipe 29b to adjust the amount of water supplied to the fermentation tank 52. 29c is provided.

The operation of the fermentation tank 52 and the atmosphere discharge valve 25, the first inflow control valve 23, the inert gas master valve 27, and the moving device 20 installed around the fermenter 52 is detected by the fermentation tank controller 28. Control signals according to the detection signals of (71, 78, 79). In addition, the operation of the water supply control valve 29c of the water supply device 29 is such that the RDF in the fermentation tank 52 is anaerobic fermentation according to the amount of RDF-containing water measured during the RDF manufacturing process and the amount of RDF input from the fuel injection tank 11. The fermentation tank control unit 28 is controlled so that the amount of water suitable for.

In the fermentation tank 52 of the above structure, the RDF injected into the fermentation tank 52 through the injection port 18 by the injection equipment 51 falls to the injection side 52a of the moving device 20. As the RDF of the fermentation tank 52 is sequentially transported downstream by the moving device 20, it moves from the input side 52a to the discharge side 52b over a predetermined fermentation period (here about 15 to 20 days). During this migration, anaerobic fermentation of organics contained in the RDF proceeds, biogas is produced, and the RDF is reduced and reduced. The composition of biogas generated by the fermentation of RDF is approximately 60% methane gas and 40% carbon dioxide. However, the amount and composition of biogas vary depending on the amount and type of organic matter contained in the RDF, and the amount of biogas also changes depending on the progress of fermentation.

When the RDF has moved to the discharge side 52b of the fermentation tank 52 while fermenting, most of the organic matter in the RDF is decomposed to become biogas, and the rest is fermentation residue. The fermentation residue of the RDF is composed of an unfermented component of a volatile component and a component that is not fermented of an RDF in the solid portion of the RDF, and includes organic residues, wood residues, and residues such as vinyl. In addition, when the fermentation period in the fermentation tank 52 is short, unfermented and the fermentation intermediate RDF may be mixed in fermentation residue, but these are also called fermentation residue. The fermentation residue is sent to the outlet 19 by the moving device 20 and discharged out of the fermentation tank 52 at the outlet 19. Fermentation residue is greatly reduced compared to the original RDF.

The residue discharge device 55 recovers the fermentation residue of the fermentation tank 52 to dehydrate and remove the digestion liquid and the digestion liquid contained in the fermentation residue. The residue discharge device 55 mainly includes a residue storage tank 41 connected to the discharge port 19 of the fermentation tank 52, and a digestion liquid dehydration removal device 43 connected through the residue storage tank 41 and the residue supply path 42. And a drainage pit 46 for storing the extinguishing liquid recovered from the residue in the residue storage tank 41 and the extinguishing liquid dehydration removal device 43. Between the discharge port 19 of the fermentation tank 52 and the residue storage tank 41, the 1st residue discharge valve 44 which divides these and controls the movement to the residue feed path 41 of the fermentation residue is provided. Between the residue storage tank 41 and the residue supply path 42, the 2nd residue discharge valve 45 which divides these and regulates the movement to the residue supply path 42 of a fermentation residue is provided. The operation of the first residue discharge valve 44, the second residue discharge valve 45, and the digestion liquid dehydration removal device 43 is controlled by the residue discharge device control unit 47.

The operation | movement of the residue discharge apparatus 55 of the said structure is demonstrated. The residue discharge device control unit 47 receives the fermentation residue discharge instruction input through a control panel (not shown), and opens the first residue discharge valve 44 by a predetermined first discharge time. The first discharge time is set according to the moving speed of the substance in the fermentation tank 52 by the moving device 20 and the amount of the fermentation residue. When the first residue discharge valve 44 is opened, the fermentation residue of the fermentation tank 52 is introduced into the residue storage tank 41 by the moving device 20 through the discharge port 19. In the residue storage tank 41, the digestion liquid is separated from the fermentation residue, and the digestion liquid separated from the fermentation residue is drained to the drain pit 46. In this manner, in the state where the extinguishing liquid of the fermentation residue is removed to some extent, the residue discharge device control unit 47 opens the second residue discharge valve 45 by a predetermined second discharge time. The second discharge time is set in accordance with the amount of fermentation residue. When the second residue discharge valve 45 is opened, the residue storage tank 41 is sent to the extinguishing liquid dehydration removal device 43 through the residue supply path 42. The fermentation residue sent to the digestion liquid dehydration removal device 43 is further dewatered here, and the digestion liquid separated from the fermentation residue is drained to the drain pit 46. In the residue discharge device 55 as described above, the fermented residue that has been reduced, reduced and dehydrated is conveyed from the digestion liquid dehydration removal device 43 to the MSW storage pit 31 of the fuel production unit 30 and reused as a raw material of the RDF. . In addition, when there exist a plurality of fuel manufacturing units 3, the fermentation residues are returned to the MSW storage pit 31 of the fuel manufacturing unit 3 which is closest to the fuel organ storage unit 5.

Here, it returns to the flow of the biogas which generate | occur | produced in the fermentation tank 52, and demonstrates. At the beginning of the RDF input, a large part of the fermenter 52 is 'empty', and the part is filled with air. Therefore, the gas which flows out from the fermentation tank 52 into the biogas first flow path 22 at the initial stage of RDF injection becomes a mixed gas of biogas generated by the fermentation of RDF and air remaining in the fermentation tank 52. Methane gas, the main component of biogas produced by anaerobic fermentation, is a combustible gas, and according to the mixing ratio of methane gas and oxygen in biogas, if the biogas contains embers, it may be exploded without being supplied with combustion oxygen from the outside. There is. Thus, the fermentation tank control unit 28 detects the composition of the outflow gas flowing out from the fermentation tank 52 to the biogas first flow path 22 using the sensors 71, 78, and 79, and mixes oxygen and methane gas in the outflow gas. Is considered to be 'compressible' when it is within the combustion range, and 'compressible' when it is outside the combustion range. When the mixing ratio of oxygen and methane gas in the outflow gas from the fermentation tank 52 is outside the combustion range, the fermentation tank control unit 28 opens the first inflow control valve 23 to primaryly discharge the outflow gas from the fermentation tank 52. The first inflow control valve 23 is controlled to be sent to the storage tank 53. In addition, the phenomenon in which the mixing ratio of oxygen and methane gas in the outflow gas from the fermentation tank 52 falls within the combustion range is remarkable when the RDF starts to be introduced into the fermentation tank 52. It is preferable to replace the air in the fermentation tank 52 with an inert gas before adding it to 52).

Fig. 6A is a graph showing the upper limit and the lower limit of the combustion of the mixed gas of natural gas and air, the vertical axis indicating the concentration of natural gas in the air, and the horizontal axis indicating the pressure of the natural gas. As shown in the same figure, the upper limit of combustion at atmospheric pressure of natural gas is 15.0 [volume in air], and the lower limit of combustion is 5.0 [volume in air]. In other words, the combustion range at atmospheric pressure of natural gas is 5.0 to 15.0 [% by volume of air]. 6B converts the upper and lower combustion limits of the mixed gas of natural gas and air shown in FIG. 6A into the relationship between the oxygen concentration and the natural gas pressure. The main component of natural gas is methane (about 85-95%). On the other hand, the composition of biogas is approximately 60% methane and 40% carbon dioxide. Natural gas is strictly different from methane gas, but safety is ensured even when the combustion range of natural gas is used as the value of the combustion range of methane gas when examining the combustion range of the outflow gas from the fermentation tank 52. . Therefore, below, when examining the combustion range (especially the lower limit of combustion value) of the outflow gas from the fermentation tank 52, it replaces the natural gas in FIG.6 (a) and FIG.6 (b) with methane gas, and shows in the same figure. The displayed data will be used.

When examining the combustion range of the outflow gas from the fermentation tank 52, it is assumed that the discharge pressure of the compressor 57 mentioned later is 5 Mpa and the temperature of the biogas after compression is 300 degreeC, for example. Here, referring to FIG. 6 (b), the lower limit of oxygen concentration when the pressure of methane gas is 5 MPa and the temperature is 300 ° C. is 8 to 9%. Therefore, if the oxygen concentration in the effluent gas from the fermentation tank 52 is 8% or less and is sent to the primary storage tank 53 as a biogas with the safety factor added, the oxygen and methane gas may be The mixing ratio is outside the combustion range. On the other hand, the upper limit of the oxygen concentration when the pressure of methane gas is 5 MPa and the temperature is 300 ° C. is about 20%. However, since the oxygen concentration in the air is about 21%, it is safe not to compress the effluent gas that exceeds the upper limit of the oxygen concentration by adding a safety factor. As described above, when the discharge pressure of the compressor 57 is 5 MPa and the temperature of the compressed biogas is 300 ° C., according to the data of FIGS. 6A and 6B, the outflow gas from the fermentation tank 52 is used. Those with a heavy oxygen concentration exceeding 8% are assumed to be within the combustion range, and likewise, those with 8% or less are assumed to be outside the combustion range.

7 is a flowchart showing the control flow of the RDF inputting initial stage of the fermenter control unit 28. When starting the fermentation of the newly introduced RDF into the fermentation tank 52, the first inflow control valve 23 and the atmospheric release valve 25 are closed, and the fermentation tank 52 is filled with initial air so that it is aerobic. . Therefore, in the fermentation tank 52, the aerobic fermentation is performed for a while after the start of the fermentation, but when the aerobic fermentation proceeds, oxygen in the fermentation tank 52 is consumed, so that the inside of the fermentation tank 52 becomes anaerobic and is transferred to anaerobic fermentation. As shown in FIG. 7, the fermentation tank controller 28 detects that biogas has been generated according to the pressure in the fermentation tank 52 detected by the pressure sensor 71 (YES in step S1), and the atmospheric release valve 25. ) Is opened (step S3). In the initial stage of the RDF input, the amount of biogas generated from the RDF is small while the amount of air remaining in the fermentation tank 52 is large. Therefore, the outflow gas from the fermentation tank 52 is a composition of 0% of methane gas and 100% of air volume initially, and the mixing ratio of oxygen and methane gas in an outflow gas exists in a combustion range (here below an upper combustion limit). With the opening of the atmospheric release valve 25, unsuitable for compression in the effluent gas from the fermentation tank 52 (that is, the mixing ratio of oxygen and methane gas is in the combustion range) causes the atmospheric release passage 24 to be opened. Through the atmosphere.

As the amount of biogas generated by the addition of RDF and the promotion of fermentation increases, the amount of remaining oxygen decreases, so that the amount of methane gas in the outflow gas from the fermentation tank 52 increases and the amount of air (oxygen) decreases. Then, the mixing ratio of oxygen and methane gas in the outflow gas from the fermentation tank 52 will be out of a combustion range (in this case, a combustion upper limit or more). The fermentor control unit 28 has a mixed ratio of oxygen and methane gas in the outflow gas from the fermentation tank 52 according to the detection values of the oxygen concentration detector 78, the methane concentration detector 79, and the pressure sensor 71. When it is finished (YES in step S2), the air inlet valve 25 is closed and the first inflow control valve 23 is opened (step S4). In this state, most of the outflow gas from the fermentation tank 52 is biogas. As the first inflow control valve 23 opens, the fermentation tank 52 and the primary storage tank 53 communicate with each other through the biogas first flow path 22, and the biomass is transferred from the fermentation tank 52 to the primary storage tank 53. Gas enters.

By the control of the fermentation tank control part 28 mentioned above, only the biogas of the compressible composition is sent to the primary storage tank 53 among the outflow gas which flowed out from the fermentation tank 52 to the biogas 1st flow path 22, Compositions that are not suitable for compression are released to the atmosphere through the atmospheric release furnace 24. In addition, although the air discharge path 24 branches in the biogas first flow path 22 in the above embodiment, it may be connected to the primary storage tank 53.

The primary storage tank 53 is a biogas storage tank for receiving biogas sent from the fermentation tank 52 through the biogas first flow passage 22. The amount of biogas sent from the fermentation tank 52 to the primary storage tank 53 varies depending on the RDF input amount into the fermentation tank 52 and the fermentation state after the input. The primary storage tank 53 is a buffer tank for storing the biogas discharged from the fermentation tank 52 and preventing abnormal rise in pressure in the fermentation tank 52. In addition, the primary storage tank 53 is also a buffer tank that buffers an imbalance between the suction flow rate of the compressor 57 and the amount of biogas generated in the fermentation tank 52. For this purpose, the primary storage tank 53 preferably has a sufficient capacity.

The primary storage tank 53 is connected to one or a plurality of secondary storage tanks 54 through a pipe forming the biogas second flow path 56. The biogas second flow path 56 is provided with a compressor 57, a cooler 83, and a second inflow control valve 80 in the secondary storage tank 54 in order from the upstream side. In addition, the primary storage tank 53 is provided with a pressure sensor 72 for sensing the pressure in the primary storage tank 53, the primary storage tank (upstream side than the compressor 57 of the biogas second flow path 56) 53, an oxygen concentration detector 73 for detecting the oxygen concentration of the biogas inside is provided. The compressor control unit 60 receives the detection signals from the pressure sensor 72 and the oxygen concentration sensor 73, and the biogas of the primary storage tank 53 is properly compressed by the compressor 57 to the secondary storage tank 54. The compressor 57 and the second inflow control valve 80 are controlled to be sent so that the pressure in the primary storage tank 53 does not become a negative pressure. The oxygen concentration detector 73 detects the oxygen concentration in the compressed biogas, and the compressor controller 60 determines whether the biogas can be compressed according to the detection result.

In the present embodiment, the primary storage tank 53 is connected to two secondary storage tanks 54, but the head of the secondary storage tank 54 is not limited thereto. The head, capacity and internal pressure of the secondary storage tank 54 are determined according to the amount of RDF to be processed and the amount of biogas generated during the storage period. However, it is preferable that the pressure of the biogas in the secondary storage tank 54 is 2-5 Mpa from a construction cost of the secondary storage tank 54 or the general purpose of the compressor 57. When the pressure of the biogas is higher than this, it is preferable to increase the base of the secondary storage tank 54. In addition, when the installation space of the secondary storage tank 54 is restricted, the pressure of the biogas in the secondary storage tank 54 may be 2-5 Mpa or more.

As described above, the biogas generated by the anaerobic fermentation of the RDF is balanced with the pressure in the fermentation tank 52 in the primary storage tank 53, compressed in the compressor 57, cooled in the cooler 83, Stored in secondary storage tank 54. Since the biogas stored in the secondary storage tank 54 is reduced by compression, the space for storing the biogas can be reduced. In addition, since the biogas is a gas, the state is easier to manage as compared with the case where the RDF which is easy to ferment is stored as it is, and handling at the time of storage is easy.

The biogas stored in the secondary storage tank 54 is supplied to the boiler 61 of the power generation part 6 by the biogas supply facility 59. The secondary storage tank 54 is connected to a biogas supply path 58 for supplying biogas to the boiler 61. The biogas supply path 58 is provided in the order of the tank opening / closing valve 81, the methane concentration sensor 75 for detecting the methane concentration of the biogas, and the biogas supply master valve 77 from the upstream side. The biogas supply passage 58 branches in two directions on the downstream side of the methane concentration sensor 75, and from the bifurcated branch downstream, the primary combustion air supply passage 65 and the secondary combustion air supply passage 66 to the boiler 61. Are each connected to). A flow regulating valve 85 for regulating the amount of biogas supply to each of the supply passages 65 and 66 between the bifurcation branch and the primary combustion air supply passage 65 and between the bifurcation branch and the secondary combustion air supply passage 66. 86) is installed. The biogas supply control unit 70 may include a pressure sensor 76 of the secondary storage tank 54, a detection signal of the methane concentration sensor 75, a primary combustion air amount or a secondary combustion air amount to the boiler 61, and a boiler 61. The operation of the tank opening / closing valve 81, the biogas supply master valve 77, and the flow regulating valves 85, 86 is controlled in accordance with the combustion load information.

Depending on the structure of the boiler 61, it is sometimes desirable to prioritize the mixing of secondary combustion air and biogas over the mixing of primary combustion air and biogas, so that the biogas stored in the secondary storage tank 54 is generally The furnace is sent to the secondary combustion air supply path 66 and supplied to the combustion chamber 61a of the boiler 61 instead of secondary combustion air or as a mixer with secondary combustion air. To this end, the biogas supply control unit 70 opens the tank opening / closing valve 81 and the biogas supply master valve 77, and adjusts the flow rate of the biogas in the flow rate adjusting valve 86. When mixing biogas and secondary combustion air, the flow rate of biogas is adjusted by the flow regulating valve 86. Here, the flow rate of the biogas is a mixture ratio of air and methane gas in the secondary combustion air and the mixed air of biogas in order to prevent abnormal combustion in the supply flow path of the mixed gas of air and biogas (Fig. 6 ( and a mixing ratio below the lower combustion limit shown in a). To this end, the biogas supply control unit 70 controls the opening and closing of the flow regulating valve 86 according to the secondary combustion air amount to the boiler 61, the methane concentration of the biogas, and the combustion load information of the boiler 61.

As described above, biogas is generally the only one sent to secondary combustion air supply path 66. However, when the boiler load increase command is issued according to the combustion load information of the boiler 61, it is difficult to increase the RDF input amount, and when the amount of biogas mixture into the secondary combustion air is limited by the lower combustion limit, the biogas is the primary combustion air. It is also sent to the supply path 65. To this end, the biogas supply control unit 70 adjusts the opening degree of the flow rate control valve 85. Here again, the amount of primary combustion air to the boiler 61 is set so that the mixing ratio of air and methane gas in the mixer of primary combustion air and biogas is outside the combustion range (mixing ratio below the lower combustion limit shown in Fig. 6A). The opening / closing and opening degree of the flow regulating valve 85 are adjusted to adjust the biogas supply amount to the primary combustion air supply passage 65 according to the methane concentration of the biogas and the combustion load information of the boiler 61.

In addition, when the calorie of the biogas stored in the secondary storage tank 54 is high enough to be used as a starting fuel of the boiler 61, the biogas is used as the starting fuel of the boiler 61 or its auxiliary fuel. Can be. In this case, as shown by the dashed-dotted line in FIG. 4, the flow path connected to the starting fuel supply path 67 in parallel with the passage connected to the primary combustion air supply path 65 and the secondary combustion air supply path 66. And a flow rate adjusting valve 87 in this flow path. The biogas supply control unit 70 opens the tank opening / closing valve 81 and the biogas supply master valve 77 at the time of starting the boiler 61 and adjusts the opening degree of the flow regulating valve 87 to control the biogas. It supplies to the starting fuel supply path 67 of the boiler 61. When the biogas is used as fuel for starting the boiler 61, the biogas pressure in the secondary storage tank 54 is set to a pressure required by the burner for starting the boiler 61, It is preferable that the pressure can be maintained even after.

Here, the flow from the recovery of MSW to the power generation using RDF fuel in the RDF combustion power generation system 1 having the above configuration will be described. First, an RDF is manufactured from the MSW recovered by the fuel manufacturing unit 3. The manufactured RDF is temporarily stored in the fuel reservoir 36 of the fuel temporary storage section 4. When the boiler 61 of the power generation unit 6 is operating, the RDF stored in the fuel reservoir 36 is supplied to the boiler 61 as fuel. In the power generation section 6, the RDF is burned in the boiler 61, and the heat is recovered to generate high temperature and high pressure steam, thereby generating power by rotating the turbine of the steam turbine power generation facility 62. On the other hand, when the boiler 61 of the power generation unit 6 is stopped or when long-term storage of the RDF (for example, one week or longer) is required, the RDF stored in the fuel reservoir 36 is first fueled. From the one stored in the reservoir 36, it is in turn sent to the fuel organ storage 5.

In the fermentation tank 52 of the fuel long-term storage unit 5, RDF is anaerobic fermented to generate biogas and fermentation residue. The fermentation residue generated by the anaerobic fermentation of the RDF is discharged from the fermentation tank 52 to remove moisture, and then returned to the fuel production section 3 to be used as a raw material of the RDF. On the other hand, the biogas generated by the anaerobic fermentation of RDF is sent to the primary storage tank 53, compressed by the compressor 57, cooled by the cooler 83, and then sent to the secondary storage tank 54 for storage. The biogas stored in the secondary storage tank 54 is supplied to the boiler 61 at the time of the operation | movement of the power generation part 6, and used as fuel or auxiliary fuel. For this reason, the boiler 61 immediately after starting becomes a mixed combustion operation of RDF and biogas. When all of the biogas generated by the fermentation of the RDF in the fuel long-term storage unit 5 is exhausted, the boiler 61 becomes an RDF combustion operation.

In addition, although the RDF is not sent from the fuel temporary storage part 4 to the fuel long-term storage part 5 at the time of the operation | movement of the power generation part 6 in the above, the fuel temporary storage part 4 also when the power generation part 6 is operated. RDF may be sent from the fuel organ storage unit 5 to the fuel organ storage unit 5. For example, in order to balance the RDF supply amount and the demand quantity of the power generation section 6 to the boiler 61, the fuel long-term storage section 5 while supplying the RDF from the fuel temporary storage section 4 to the power generation section 6. You can store RDF In this way, a space for storing the RDF including the fuel temporary storage unit 4 and the fuel organ storage unit 5 can be further reduced. In addition, it becomes possible to balance the supply and demand of the RDF produced from the MSW and the RDF consumed in the boiler 61.

As described above, the RDF combustion power generation system 1 stores the surplus RDF in the form of biogas and fermentation residue. Since biogas is a gas, it is easier to manage long-term storage and long-term storage in an enclosed space as compared with the case of storing a solid RDF in a conventional RDF reservoir. In addition, gas can be easily reduced by compression, and the biogas is stored in a compressed state so that the space for storage can be hidden. In addition, since the fermentation residue is dehydrated, reduced and reduced, it is possible to reduce the space for storing the solids as compared with the case of storing the RDF, so that it is easy to manage the storage. In short, according to the fuel long-term storage part 5 of the RDF combustion power generation system 1, it is possible to realize the reduction of the space for storing the RDF and the prevention of the methane gas fire generated by the aerobic fermentation during the long-term storage of the RDF. . In addition, the RDF changes form into biogas and fermentation residue, but since the biogas is reused as fuel in the boiler 61 and the fermentation residue is used as a raw material of the RDF, the RDF energy is utilized without exception. In addition, in the fuel long-term storage section 5 of the RDF combustion power generation system 1, it is possible to store RDF that is easy to ferment in a dry environment or even under a high temperature and high humidity environment. Can be stored reliably.

While a preferred embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, but various design changes can be made within the scope of the claims.

For example, in the fuel long-term storage unit 5 according to the above embodiment, the mixture of oxygen and methane gas in the effluent gas from the fermentation tank 52 in the combustion range is released to the atmosphere because it cannot be compressed and stored. The effluent gas may be used as energy without being collected and compressed. FIG. 8 is a conceptual diagram showing a configuration of an upstream side of the primary storage tank of the fuel long-term storage unit according to the modification, and FIG. 9 is a conceptual diagram illustrating a configuration of a downstream side of the primary storage tank of the fuel long-term storage unit according to the modification. The modified example of the fuel organ storage part 5 shown in such a figure is the preliminary storage tank 92 connected to the fermentation tank 52 via the biogas third flow path 91 compared with the fuel organ storage part 5 shown in FIG. It differs in the point provided. The third inflow control valve 93, which is opened and closed by the fermentation tank control unit 28, is provided in the biogas third flow path 91. The preliminary storage tank 92 is provided with an air discharge path 24 and an air discharge valve 25. The preliminary storage tank 92 is connected to the primary combustion air supply passage 65 and the secondary combustion air supply passage 66 of the boiler 61 through the second biogas supply passage 95. The second biogas supply passage 95 includes a low pressure blower 96 for sending biogas in the preliminary storage tank 92, a methane concentration detector 84, and respective combustion air supply passages 65, 66. Flow regulating valves 97 and 98 are provided for regulating the flow rate of the biogas to be supplied. In the fuel long-term storage unit 5 of the above-described configuration, the fermentation tank control unit 28 mixes oxygen and methane gas of the effluent gas from the fermentation tank 52 according to the detection values of the concentration detector 78 and the methane concentration sensor 79. Is within the combustion range, the third inlet control valve 93 is opened. Accordingly, the mixing ratio of methane gas and oxygen is in the combustion range, and the effluent gas (mixture of biogas and air) which is not suitable for compression is sent to the preliminary storage tank 92 and stored in the preliminary storage tank 92. The biogas stored in the preliminary storage tank 92 without being compressed is supplied to the primary combustion air supply passage 65 through the second biogas supply passage 95 by the low pressure blower 96 when the power generation unit 6 is operated. And at least one of the secondary combustion air supply paths 66 to be used as fuel of the boiler 61.

Further, for example, the RDF combustion power generation system 1 according to the above embodiment is a system for generating RDF produced from MSW as a fuel, but using the solid fuel derived from biomass waste produced from biomass waste as fuel. It can also be applied to developing systems. In this case, in the above embodiment, when the MSW is replaced with the biomass waste and the RDF with the solid fuel derived from the biomass waste, the embodiment to which the present invention is applied to the RDF combustion power generation system 1 of the biomass waste. This can be explained.

The present invention is useful for long-term storage of waste-derived solid fuels, such as fluff RDF and biomass-based solid fuels, which are easily fermented, in a stable state.

1: RDF combustion power generation system
3: fuel manufacturing department
4: fuel temporary storage
5: fuel long term storage
6: power generation
20: conveying device
22: first biogas flow path
23: first inflow control valve
25: atmospheric release valve
31: MSW storage feet
36: fuel reservoir
51: input device
52: fermenter
53: primary storage tank (biogas storage)
54: secondary storage tank (biogas storage)
55: residue discharge device
56: second biogas
57: compressor
58: biogas supply
59: biogas supply system
61: boiler
62: steam turbine power plant
63: exhaust gas treatment plant
65: primary combustion air supply
66: secondary combustion air supply
92: reserve storage tank

Claims (22)

It is a storage facility for storing waste-derived solid fuel, which is easy to ferment, before burning in a combustion plant,
A fermentation tank for anaerobic fermentation of the waste-derived solid fuel,
A biogas storage tank for storing biogas generated by anaerobic fermentation of the waste-derived solid fuel;
A first flow path for sending the biogas from the fermentation tank to the biogas storage tank,
And a supply passage for supplying the biogas from the biogas storage tank to the fuel equipment. The method of claim 1,
The biogas storage tank includes a primary storage tank through which the biogas is sent from the fermentation tank through the first flow passage, and a secondary storage tank connected to the primary storage tank and a second flow passage,
A compressor for compressing and sending the biogas from the primary reservoir to the secondary reservoir in the second flow path;
And a cooler for cooling the biogas compressed by the compressor in the second flow path. 3. The method according to claim 1 or 2,
And water removal means for removing water contained in the fermentation residue of the waste-derived solid fuel and water contained in the fermentation residue of the waste-derived solid fuel discharged from the fermentation tank. The method according to any one of claims 1 to 3,
An oxygen concentration detector for detecting an oxygen concentration of the effluent gas flowing out of the fermenter into the first flow path;
A methane concentration detector for detecting methane concentration of the effluent gas;
And a first control valve which opens when the oxygen and methane gas mixing ratio of the effluent gas is outside the combustion range according to the sensed oxygen concentration and the methane concentration to communicate the first flow path with the biogas storage tank. Storage facility for derived solid fuels. 5. The method of claim 4,
An air discharge furnace communicating the inside of the fermentation tank with the atmosphere;
According to the oxygen concentration detected by the oxygen concentration detector and the methane concentration detected by the methane concentration detector, the oxygen and methane gas mixture ratio of the effluent gas is opened when it is within a combustion range to release the effluent gas to the atmosphere through the atmospheric discharge path. And an atmospheric release valve for storing waste-derived solid fuel. 5. The method of claim 4,
A preliminary storage tank connected with the fermentation tank through a third flow path,
An oxygen and methane gas mixing ratio of the effluent gas is opened to communicate the third flow path with the preliminary storage tank according to the oxygen concentration detected by the oxygen concentration detector and the methane concentration detected by the methane concentration detector. 2. A storage facility for waste-derived solid fuel, comprising two control valves. 7. The method according to any one of claims 1 to 6,
The supply path has a path for supplying the biogas stored in the biogas storage tank to the combustion facility as a starting fuel of the combustion facility, wherein the waste-derived solid fuel storage facility. The method according to any one of claims 1 to 7,
The supply passage has a path for supplying the biogas stored in the biogas storage tank to at least one of the primary combustion air supply path and the secondary combustion air supply path of the combustion facility. Storage equipment. The method of claim 8,
The supply passage is provided with adjusting means for adjusting the supply amount of the biogas such that the biogas supplied to the combustion facility is mixed with the primary combustion air or the secondary combustion air of the combustion facility at a mixing ratio outside the combustion range. Storage equipment for waste-derived solid fuel. 10. The method according to any one of claims 1 to 9,
And said waste-derived solid fuel is a waste solidification fuel produced from general waste. 10. The method according to any one of claims 1 to 9,
And said waste-derived solid fuel is a biomass waste-derived solid fuel produced from biomass-based waste. A method of storing waste-derived solid fuel, which is easy to ferment, before burning in a combustion plant,
Anaerobic fermentation of the waste-derived solid fuel in an anaerobic fermenter;
And storing the biogas generated by anaerobic fermentation of the waste-derived solid fuel in a biogas storage tank. 13. The method of claim 12,
The step of storing the biogas in a biogas storage tank
Receiving biogas from the fermenter in a primary reservoir,
Compressing and sending the biogas from the primary reservoir to the secondary reservoir by compressing the biogas;
Cooling the compressed biogas;
Storing the compressed biogas in the secondary storage tank. The method according to claim 12 or 13,
And removing water contained in the fermentation residue of the waste-derived solid fuel and water contained in the fermentation residue of the waste-derived solid fuel discharged from the fermentation tank. 15. The method according to any one of claims 12 to 14,
In the step of storing the biogas in a biogas storage tank,
The oxygen concentration and the methane concentration of the effluent gas flowing out from the fermentation tank containing the biogas is sensed, and according to the detection result, the mixing ratio of the oxygen and methane gas in the effluent gas is outside the combustion range. How to store waste-derived solid fuel. The method of claim 15,
In the step of storing the biogas in a biogas storage tank,
And a method of storing the waste-derived solid fuel according to the oxygen concentration and the methane concentration of the effluent gas. The method of claim 15,
In the step of storing the biogas in a biogas storage tank,
Storage of the waste-derived solid fuel, characterized in that the mixing ratio of the oxygen and methane gas in the effluent gas in the combustion range according to the oxygen concentration and the methane concentration of the effluent gas is stored in a preparatory tank different from the biogas storage tank. Way. 18. The method according to any one of claims 12 to 17,
And storing the biogas stored in the biogas storage tank as the fuel for starting the combustion plant, to the combustion plant. 19. The method according to any one of claims 12 to 18,
And supplying the biogas stored in the biogas storage tank to at least one of a primary combustion air supply path and a secondary combustion air supply path of the combustion facility. . The method of claim 19,
And adjusting the supply amount of the biogas so that the biogas supplied to the combustion facility is mixed with the primary combustion air or the secondary combustion air of the combustion facility at a mixing ratio outside the combustion range. 21. The method according to any one of claims 12 to 20,
And said waste-derived solid fuel is a waste solidification fuel produced from general waste. 21. The method according to any one of claims 12 to 20,
And said waste-derived solid fuel is a biomass waste solid fuel produced from biomass-based waste.

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