Sewage sludge solid fuel supply equipment and supply method for shaft furnace gasification and melting system

Abstract

To expand usage of biomass and contribute to reduction of CO2 emissions in a shaft furnace type gasification melting system.SOLUTION: A shaft furnace type gasification melting system includes: a shaft furnace type gasification melting furnace A for drying, gasifying, burning and melting waste; a secondary combustion chamber B for burning combustible gas generated in the gasification melting furnace A and combustible dust accompanying the gas; and a boiler installed at a rear stage of the secondary combustion chamber. Sewage sludge solid fuel is input to the gasification melting furnace A, and sewage sludge solid fuel pulverized into fine powder is blown into the secondary combustion chamber B.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a supply system and a supply method for sewage sludge solid fuel in a shaft furnace gasification and melting system. [Background technology]

[0002] In a shaft furnace gasification melting system, waste is fed into the top of the shaft furnace gasification melting furnace along with coke and limestone. After the moisture in the waste evaporates in the drying and preheating zone, the combustible material is pyrolyzed and gasified. The coke is burned with air and oxygen supplied from the tuyere (blowing nozzle) installed at the bottom of the gasification melting furnace, forming a high-temperature molten zone in which the ash is completely melted. The molten material is discharged from the outlet at the bottom of the gasification melting furnace into a water tank, where it is rapidly cooled and becomes granular slag and metal, which are then separated and recovered using a magnetic separator for effective use. Meanwhile, the combustible gas, also known as gasification gas or pyrolysis gas, generated in the gasification melting furnace is introduced into a dust collector, where some of the dust is removed, and then introduced into a secondary combustion chamber along with the combustible dust that passed through the dust collector for complete combustion. The combustion exhaust gas generated in the secondary combustion chamber is introduced into a boiler in the downstream stage for heat recovery. A major feature of the shaft furnace gasification and melting system is that by separating and controlling the gasification and melting furnace and secondary combustion chamber individually, it is possible to achieve both complete melting and complete combustion.

[0003] However, when melting waste in a gasification melting furnace, the amount of combustible gas generated by the gasification melting furnace fluctuates depending on the characteristics of the waste and the furnace conditions, which causes fluctuations in the combustion load in the secondary combustion chamber downstream, leading to fluctuations in the main steam flow rate and power generation.Furthermore, when such phenomena occur, the amount of coke and reheating fuel used increases, which leads to problems such as increased CO2 emissions.

[0004] To address these issues, Patent Document 1 discloses a technology in which combustible dust generated from a gasification and melting furnace is collected and temporarily stored, and then injected into a secondary combustion chamber at a later stage, thereby stabilizing the combustion load in the secondary combustion chamber and the main steam flow rate in the boiler, and ultimately stabilizing the amount of power generation.

[0005] Meanwhile, Patent Document 2 discloses a technology for feeding wood chips, a type of biomass, into a gasification and melting furnace. In recent years, there has been an increasing demand for reducing CO2 emissions, and therefore there is a demand for expanded use of biomass in shaft furnace gasification and melting systems. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 2629117 [Patent Document 2] Patent No. 5601688 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to expand the use of biomass in shaft furnace gasification and melting systems and contribute to reducing CO2 emissions. [Means for solving the problem]

[0008] To solve the above problems, the present inventors focused on sewage sludge solid fuel as a biomass material. Sewage sludge solid fuel is a fuel made from sewage sludge as a primary raw material, solidified by carbonization, drying, etc., and JIS standards have been established. Sewage sludge generated at sewage treatment plants has the advantages of being stable in both quality and quantity, being concentrated, and being generated in cities where there is demand. In addition, sewage sludge solid fuel generally has the advantage of being in the form of granules with a size (maximum particle diameter) of less than several tens of millimeters, making it easy to handle, and has the advantage of having a high yet stable gross calorific value of approximately 14 to 19 MJ / kg. For these reasons, the present inventors focused on sewage sludge solid fuel as a biomass material and conducted extensive testing and investigations to utilize sewage sludge solid fuel in a shaft furnace gasification and melting system. As a result, they discovered that one effective way to utilize sewage sludge solid fuel is to inject pulverized sewage sludge solid fuel into a secondary combustion chamber.

[0009] That is, according to one aspect of the present invention, a shaft furnace gasification and melting system has a shaft furnace gasification and melting furnace that dries, gasifies, burns, and melts waste, a secondary combustion chamber that burns combustible gas generated in the gasification and melting furnace and combustible dust accompanying the gas, and a boiler installed downstream of the secondary combustion chamber, and is equipped with a system (hereinafter referred to as the "first system") for injecting pulverized sewage sludge solid fuel into the secondary combustion chamber. In addition, a system (hereinafter referred to as the "second system") is provided for feeding sewage sludge solid fuel into the gasification and melting furnace. , and a sewage sludge solid fuel supply facility will be provided.

[0010] According to another aspect of the present invention, there is provided a shaft furnace type gasification and melting system having a shaft furnace type gasification and melting furnace for drying, gasifying, burning and melting waste, a secondary combustion chamber for burning combustible gas generated in the gasification and melting furnace and combustible dust accompanying the gas, and a boiler installed downstream of the secondary combustion chamber, The sewage sludge solid fuel is fed into the gasification and melting furnace, A method for supplying sewage sludge solid fuel, comprising injecting pulverized sewage sludge solid fuel into a secondary combustion chamber. [Effects of the Invention]

[0011] According to the present invention, it is possible to expand the use of biomass in a shaft furnace gasification and melting system, thereby contributing to a reduction in CO2 emissions. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a conceptual diagram of a shaft furnace gasification and melting system that applies a sewage sludge solid fuel supply facility according to one embodiment of the present invention. [Figure 2]Schematic diagram of the gasification and melting furnace in a shaft furnace gasification and melting system. [Figure 3] Graph showing the results of a combustion test of sewage sludge solid fuel in a small tubular furnace. [Figure 4A] Graph showing the effect of reducing coke consumption by using sewage sludge solid fuel. [Figure 4B] A graph showing the effect of reducing city gas consumption using sewage sludge solid fuel. [Figure 4C] Graph showing the effect of improving power generation using sewage sludge solid fuel. DETAILED DESCRIPTION OF THE INVENTION

[0013] FIG. 1 conceptually shows a shaft furnace gasification and melting system to which a sewage sludge solid fuel supply facility according to one embodiment of the present invention is applied. As described above, in the shaft furnace gasification and melting system, waste is fed into the top of shaft furnace gasification and melting furnace A along with coke and limestone. After the moisture in the waste evaporates in the drying and preheating zone, the combustible material is pyrolyzed and gasified. The coke is burned with air and oxygen supplied from tuyere (blower nozzle) A1 installed at the bottom of the gasification and melting furnace, forming a high-temperature molten zone in which the ash is completely melted. The molten material is discharged from the outlet at the bottom of the gasification and melting furnace into a water tank, where it is rapidly cooled and becomes granular slag and metal, which are then separated and recovered using a magnetic separator for effective use. Meanwhile, the combustible gas generated in the gasification and melting furnace is partially removed from the dust by a dust collector (not shown), and then introduced into the downstream secondary combustion chamber B together with the combustible dust that passed through the dust collector for complete combustion. The combustion exhaust gas generated in the secondary combustion chamber B is introduced into the downstream boiler for heat recovery. In the following explanation, "waste" will be written as "garbage."

[0014] In this embodiment, the main purpose of this shaft furnace gasification and melting system is to expand the use of biomass and contribute to reducing CO2 emissions, and the system is equipped with a system (hereinafter referred to as the "first system") 1 for injecting pulverized sewage sludge solid fuel into the secondary combustion chamber B, and a system (hereinafter referred to as the "second system") 2 for feeding the sewage sludge solid fuel into the gasification and melting furnace A. Here, "sewage sludge solid fuel" refers to a fuel that meets the requirements of JIS Z 7312:2014, and will be referred to as "sludge fuel" in the following explanation.

[0015] In this embodiment, to prevent the dispersion of dust and odors during transportation, the sludge fuel is transported to the sludge fuel supply facility by a jet pack vehicle 3 as shown in Figure 1. The transported sludge fuel is air-transported to a storage hopper 5 by a receiving blower 4 and stored in the storage hopper 5. The sludge fuel in the storage hopper 5 is divided into two systems, the first system 1 and the second system 2, and introduced into the secondary combustion chamber B and the gasification and melting furnace A.

[0016] In this embodiment, the first system 1 is equipped with a pulverizer 11 capable of pulverizing sludge fuel. Specifically, in this embodiment, sludge fuel discharged from the first constant-amount dispensing device 51 at the bottom of the storage hopper 5 to the first system 1 is transported to the pulverizer 11 by a transfer conveyor (not shown). The pulverized sludge fuel passes through the pulverizer 12, the pulverized material storage hopper 13, and the pulverized material injection hopper 14, and is then injected into the secondary combustion chamber B by the injection blower 15. In this embodiment, the provision of the first system 1 for injecting the pulverized sludge fuel into the secondary combustion chamber B allows for expanded use of sludge fuel, i.e., biomass, in the shaft furnace gasification and melting system, contributing to a reduction in CO2 emissions.

[0017] In this embodiment, a fixed quantity feed device 141 is provided at the bottom of the pulverized material injection hopper 14, and the amount of sludge fuel injected into the secondary combustion chamber B can be controlled by controlling the amount of sludge fuel fed by this fixed quantity feed device 141. Specifically, in this embodiment, the amount of sludge fuel injected into the secondary combustion chamber B is controlled according to at least one of the main steam flow rate in the boiler and the secondary combustion chamber temperature. More specifically, for example, if the main steam flow rate in the boiler is lower than a specified amount, the amount of sludge fuel injected into the secondary combustion chamber B is increased, and conversely, if the main steam flow rate is higher, the amount of sludge fuel injected into the secondary combustion chamber B is decreased. Also, for example, if the secondary combustion chamber temperature is lower than a specified temperature, the amount of sludge fuel injected into the secondary combustion chamber B is increased, and conversely, if the secondary combustion chamber temperature is higher, the amount of sludge fuel injected into the secondary combustion chamber B is decreased. In this way, by providing a mechanism for controlling the amount of sludge fuel injected into the secondary combustion chamber B according to at least one of the main steam flow rate in the boiler and the temperature of the secondary combustion chamber, it is possible to suppress fluctuations in the combustion load in the secondary combustion chamber B, and as a result, it is possible to suppress fluctuations in the main steam flow rate and the amount of power generation. This makes it possible to reduce the amount of coke used and the amount of reheating fuel used.

[0018] Meanwhile, in the second system 2, the sludge fuel discharged from the second constant volume discharge device 52 at the bottom of the storage hopper 5 is air-transported by the conveying blower 21 to the feeding hopper 22, and then fed from this feeding hopper 22 into the gasification and melting furnace A. As described above, in this embodiment, in addition to the above-mentioned first system 1, the second system 2 for feeding the sludge fuel into the gasification and melting furnace A is provided, which allows for further expansion of the use of sludge fuel, i.e., biomass, in the shaft furnace gasification and melting system, and contributes to further reductions in CO2 emissions.

[0019] In this embodiment, a fixed-volume feeder 221 is provided at the bottom of the feed hopper 22. The amount of sludge fuel fed into the gasification and melting furnace A can be controlled by controlling the amount of sludge fuel fed by this fixed-volume feeder 221. Specifically, in this embodiment, the amount of sludge fuel fed into the gasification and melting furnace A is controlled according to the furnace top gas temperature and the pressure difference within the furnace. This is to prevent the occurrence of a blow-by phenomenon, in which gas flows through a specific path in a low-airflow-resistance portion of the packed waste bed in the furnace due to fluctuations in the waste quality, particularly the waste calorie content, fed from the top during operation of the gasification and melting furnace A. Specifically, when a blow-by phenomenon occurs, high-temperature combustion gas (hot air) generated by the combustion of coke and pyrolysis residue with air and oxygen in the lower part of the furnace flows directly toward the top of the furnace without exchanging heat with the waste. This significantly reduces the heat exchange efficiency within the furnace, resulting in a significant fluctuation (decrease) in the amount of combustible gas generated from the gasification and melting furnace. This blow-by phenomenon will be explained in more detail with reference to FIG.

[0020] As shown in Figure 2, waste is fed into the top of the gasification and melting furnace A to form a packed bed, and hot air is fed into the packed bed from the bottom of the furnace to exchange heat, drying and pyrolyzing the waste. As shown in Table 1, the lower the waste calorie (the more moisture there is in the waste), the higher the furnace top gas temperature T and the lower the furnace pressure difference ΔP = P2 - P1. This is because the hot air from the bottom of the furnace blows through to the top of the furnace without exchanging heat with the waste.

[0021] [Table 1]

[0022] On the other hand, as shown in Table 2, the more the sludge fuel input ratio is increased, the more the sludge fuel fills the gaps in the packed bed of waste, increasing the pressure difference ΔP inside the furnace and promoting heat exchange between the hot air and the waste, which in turn reduces the furnace top gas temperature T.

[0023] [Table 2]

[0024] In this way, by increasing or decreasing the sludge fuel input ratio in response to fluctuations in waste calorie content, the blow-by phenomenon, which occurs due to fluctuations in waste quality, can be controlled. In other words, by controlling the amount of sludge fuel input to the gasification and melting furnace A in response to the furnace top gas temperature T and the furnace pressure difference ΔP of the gasification and melting furnace A, the occurrence of the blow-by phenomenon can be suppressed. Specifically, for example, if the furnace top gas temperature T of the gasification and melting furnace A is higher than a specified temperature, the amount of sludge fuel input to the gasification and melting furnace A is increased; conversely, if it is lower, the amount of sludge fuel input to the gasification and melting furnace A is decreased. Furthermore, for example, if the furnace pressure difference ΔP of the gasification and melting furnace A is lower than a specified value, the amount of sludge fuel input to the gasification and melting furnace A is increased; conversely, if it is higher, the amount of sludge fuel input to the gasification and melting furnace A is decreased. In this way, by providing a mechanism to control the amount of sludge fuel fed into the gasification and melting furnace A according to the furnace top gas temperature and the pressure difference inside the furnace, it is possible to prevent the occurrence of blow-by in the gasification and melting furnace A, and as a result, it is possible to prevent fluctuations (reductions) in the amount of combustible gas generated from the gasification and melting furnace A. This makes it possible to reduce the amount of coke used and the amount of reheating fuel used.

[0025] Next, the sludge fuel used in the present invention will be described. As mentioned above, the sludge fuel is a fuel that satisfies the requirements of JIS Z 7312:2014. The JIS standard stipulates that the mass fraction (%) of total moisture must be 20 or less, and therefore the present invention also uses sludge fuel whose mass fraction (%) of total moisture is 20 or less. From the viewpoint of the handleability and calorific value of the sludge fuel, it is preferable that the mass fraction (%) of total moisture is 10 or less.

[0026] On the other hand, the JIS standard does not specify the size of the sludge fuel, and the size of the sludge fuel is not particularly limited in the present invention either. However, taking into consideration ease of handling, etc., it is preferable to use granular sludge fuel with a maximum particle diameter of less than 31.5 mm, and more preferably, to use granular sludge fuel with a particle diameter of 1.0 mm or more but less than 5.6 mm. The particle size of sludge fuel is determined by whether it passes through the sieve in Table 1 of "5.1 Sieve mesh openings and wire diameter" in JIS Z 8801-1:2019. For example, sludge fuel with a maximum particle size of less than 31.5 mm is sludge fuel that passes through a sieve with a nominal mesh size of 31.5 mm. Also, sludge fuel with a particle size of 1.0 mm or more but less than 5.6 mm is sludge fuel that passes through a sieve with a nominal mesh size of 5.6 mm, but does not pass through a sieve with a nominal mesh size of 1.0 mm.

[0027] Sludge fuel with a particle size of 1.0 mm or more but less than 5.6 mm can be produced, for example, by the Jay Combi System ("Jay Combi" is a registered trademark; the same applies below), a granulation and drying method using a twin-shaft mixer and a drying drum. Sludge fuel produced by the Jay Combi System is equivalent to a granulated dried material, and is characterized by a very high volatile content and a fast combustion rate compared to coal. It also has the same ash content as coal, and is characterized by the amount of ash generated per calorific value being less than low-temperature charcoal.

[0028] In this embodiment, the second system 2 uses the received sludge fuel as is, but the first system 1 uses sludge fuel that has been pulverized into fine powder. This is to improve combustibility in the secondary combustion chamber B. From the viewpoint of improving combustibility in the secondary combustion chamber B, it is preferable that the sludge fuel in the first system 1 be pulverized to an average particle diameter of 750 μm or less and injected into the secondary combustion chamber B, and more preferably, the sludge fuel be pulverized to an average particle diameter of 200 μm or less and injected into the secondary combustion chamber B. That is, in this embodiment, the pulverizer 11 is preferably capable of pulverizing the sludge fuel to an average particle diameter of 750 μm or less and more preferably, capable of pulverizing the sludge fuel to an average particle diameter of 200 μm or less. Here, the average particle size is the weighted volume average particle size (volume average diameter) defined by the formula 5.2(15) of JIS Z 8819-2.

[0029] Figure 3 shows the results of a combustion test conducted using a small drop-tube furnace to understand the relationship between sludge fuel particle size and combustibility. The oxygen concentration in the furnace was 8% and the temperature was 1000°C. In Figure 3, "J-Combi 150-250 μm" refers to sludge fuel produced by the above-mentioned J-Combi system, which has been crushed and sieved using a sieve specified in JIS Z 8801-1:2019 to have a particle size of 150 μm or more and less than 250 μm, with an average particle size of approximately 200 μm. "J-Combi 500-1000 μm" refers to sludge fuel produced by the above-mentioned J-Combi system, which has been crushed and sieved using a sieve specified in JIS Z 8801-1:2019 to have a particle size of 500 μm or more and less than 1000 μm, with an average particle size of approximately 750 μm. "Char" refers to combustible dust generated in the gasification and melting furnace. Figure 3 plots the combustion test results for these three types of fuel (samples), and also plots the combustion test results for "J-Combi 500-1000μm" corrected to take into account the falling speed due to gravity as "J-Combi 500-1000μm (gravity taken into account)." To add a bit more about taking gravity and drop speed into account, in the combustion test, the sample is dropped from the top of a small tubular furnace, and the unburned carbon rate is calculated by comparing the unburned carbon rate of the sample as it falls from height Z1 to height Z2. The residence time is calculated from the air flow velocity constantly flowing through the small tubular furnace and the distance the sample falls. Therefore, when sample acceleration due to gravity is taken into account, the actual residence time in the small tubular furnace is likely to be shorter than this combustion test result. Therefore, in Figure 3, since the effect of acceleration due to gravity is greater with weight, the combustion test results for the larger particle size "J-Combi 500-1000μm" are plotted as "J-Combi 500-1000μm (gravity considered)," corrected to take into account the drop speed due to gravity.

[0030] As shown in Figure 3, "J-Combi 500-1000 μm (taking gravity into consideration)" has better combustibility than "char," which is an established technology and is practically injected into the secondary combustion chamber, and therefore there is no problem with burnout in the secondary combustion chamber. Therefore, as described above, in this embodiment, it is preferable to inject pulverized sludge fuel having an average particle size of 750 μm or less into the secondary combustion chamber B in the first system 1. Furthermore, as shown in Figure 3, "J-Combi 150-250 μm" has even better combustibility than "J-Combi 500-1000 μm (taking gravity into consideration)," and therefore it is more preferable to inject pulverized sludge fuel having an average particle size of 200 μm or less into the secondary combustion chamber B in the first system 1 in this embodiment.

[0031] Although this embodiment includes a second system 2 in addition to the first system 1, the second system 2 can be omitted. The first system 1 alone can solve the problem of expanding biomass utilization and contributing to reducing CO2 emissions in a shaft furnace gasification and melting system. However, to smoothly coordinate the receiving schedule with the fuel production facility that produces sludge fuel, the equipment must be able to use the entire amount of sludge fuel received each day. In this case, it is preferable to provide an additional system as a buffer rather than just one system as in this embodiment. Furthermore, when two systems, the first system 1 and the second system 2, are provided, branching them into two systems from a single storage hopper 5, as in this embodiment, is preferable from the perspective of simplifying the equipment configuration and saving space. Furthermore, in this embodiment, the pulverizer 11 is provided within the first system 1, but it is also possible to provide a pulverizer outside the first system 1 and supply sludge fuel that has been pulverized into fine powder in advance to the first system 1. However, in order to branch into two systems from one storage hopper 5 as in this embodiment, it is preferable to provide the pulverizer 11 within the first system 1. [Example]

[0032] Operational data was collected for a shaft furnace gasification and melting system using the supply equipment shown in Figure 1, with and without the use of sludge fuel. Granular sludge fuel with a particle size of 1.0 mm or more and less than 5.6 mm, produced by the Jay Combi system described above, was used as the sludge fuel. In the first system 1, the sludge was crushed using a crusher 11 to an average particle size of 200 μm or less. Table 3 shows the operational data, and the confirmed effects are described below. The shaft furnace gasification and melting system for which operational data was collected has two systems, each with a gasification and melting capacity of 330 t / day.

[0033] [Table 3]

[0034] <Coke consumption> It was confirmed that the coke consumption ratio could be reduced as the amount of sludge fuel used increased. As mentioned above, the rectification effect of the hot air in the gasification and melting furnace increased the heat exchange efficiency between the hot air and the waste in the packed bed, enabling more efficient drying and pyrolysis of the waste, and the fixed carbon contained in the sludge fuel functioned as a heat source. These effects are thought to have reduced the heat generated by the coke in the lower part of the furnace. As shown in Figure 4A, a coke reduction effect of approximately 0.10 kg was achieved per 1 kg of sludge fuel.

[0035] <City gas consumption> City gas is used as burner fuel for the pilot light in the secondary combustion chamber and as a calorific value supplement (reheat fuel) when the waste quality fluctuates. As mentioned above, pulverized sludge fuel has high combustibility and can be used to instantaneously supplement calorific value, and the more sludge fuel is used, the less city gas is used. As shown in Figure 4B, the calorific value is approximately 0.011 Nm per kg of sludge fuel. 3 This resulted in a reduction in city gas consumption.

[0036] <Power generation amount> The sludge fuel fed into the gasification melting furnace and secondary combustion chamber is burned and recovered as energy in a boiler and steam turbine. As shown in Figure 4C, an improvement in power generation of approximately 1.28 kWh was achieved per kg of sludge fuel.

[0037] <Exhaust gas composition> As shown at the bottom of Table 1, it was confirmed that the composition of the stack exhaust gas was well below the regulatory value even when sludge fuel was added.

[0038] <CO2 emission reduction effect of sludge fuel> Based on the above results, the CO2 emission reduction effect of sludge fuel was calculated, and the results are shown in Table 4. The CO2 emission reduction per ton of sludge fuel used was estimated to be -0.317t from the reduction in coke consumption, -0.0246t from the reduction in city gas consumption, and -0.767t from the improvement in power generation, totaling -1.11t. When the sludge fuel usage ratio is 50kg / ton of waste, the CO2 emission reduction per ton of waste incinerated was estimated to be -55.4kg. Note that this time the CO2 emission reduction was calculated from the actual increase in power generation, but if the CO2 emission reduction per ton of sludge fuel used is estimated based on the actual increase in main steam generation and including heat use, it is expected that it could be improved to around -1.4t.

[0039] [Table 4] [Explanation of symbols]

[0040] A Gasification and Melting Furnace A1 tuyere B Secondary combustion chamber 1. The First Lineage 11 Crusher 12 Crushing hopper 13 Crushed material storage hopper 14 Crushed material blowing hopper 141 Quantitative cutting device 15 Intake blower 2. Second lineage 21 Conveyor blower 22 Feeding hopper 221 Quantitative cutting device 3 Jetpack Car 4 Receiving blower 5 Storage hopper 51 First fixed quantity dispensing device 52 Second fixed quantity dispensing device

Claims

1. A shaft furnace gasification and melting system having a shaft furnace gasification and melting furnace that dries, gasifies, burns and melts waste, a secondary combustion chamber that burns the combustible gas generated in the gasification and melting furnace and the combustible dust accompanying the gas, and a boiler installed downstream of the secondary combustion chamber, the system comprising a system (hereinafter referred to as the "first system") for injecting pulverized sewage sludge solid fuel into the secondary combustion chamber, and a system (hereinafter referred to as the "second system") for feeding the sewage sludge solid fuel into the gasification and melting furnace.

2. 2. The sewage sludge solid fuel supply system according to claim 1, wherein the first system injects pulverized sewage sludge solid fuel having an average particle size of 750 μm or less into the secondary combustion chamber.

3. 2. The sewage sludge solid fuel supply system according to claim 1, wherein the first system injects pulverized sewage sludge solid fuel having an average particle size of 200 μm or less into the secondary combustion chamber.

4. 4. The sewage sludge solid fuel supply facility according to claim 1, wherein the first system includes a pulverizer capable of pulverizing the sewage sludge solid fuel.

5. 2. The sewage sludge solid fuel supply system according to claim 1, wherein the second system feeds granular sewage sludge solid fuel having a maximum particle size of less than 31.5 mm into the gasification and melting furnace.

6. 6. The sewage sludge solid fuel supply system according to claim 5, wherein the second system feeds granular sewage sludge solid fuel having a particle size of 1.0 mm or more and less than 5.6 mm into the gasification and melting furnace.

7. 7. The sewage sludge solid fuel supply system according to claim 1, claim 5 or claim 6, wherein in the second system, sewage sludge solid fuel having a total moisture mass fraction (%) of 10 or less is fed into a gasification and melting furnace.

8. 8. The sewage sludge solid fuel supply facility according to claim 1, claim 5, claim 6 or claim 7, further comprising a mechanism for controlling the amount of sewage sludge solid fuel fed into the gasification melting furnace according to the furnace top gas temperature and furnace pressure difference of the gasification melting furnace.

9. 9. The sewage sludge solid fuel supply facility according to claim 1, further comprising a mechanism for controlling the amount of sewage sludge solid fuel injected into the secondary combustion chamber in accordance with at least one of the conditions of the main steam flow rate in the boiler and the temperature of the secondary combustion chamber.

10. A shaft furnace-type gasification and melting furnace system has a shaft furnace-type gasification and melting furnace that dries, gasifies, burns, and melts waste, a secondary combustion chamber that burns the combustible gas generated in the gasification and melting furnace and the combustible dust accompanying the gas, and a boiler installed downstream of the secondary combustion chamber, and a method for supplying sewage sludge solid fuel, characterized by feeding sewage sludge solid fuel into the gasification and melting furnace and injecting sewage sludge solid fuel that has been pulverized into fine powder into the secondary combustion chamber.

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