Fuel gas generating device and fuel gas generating method

Abstract

To provide a fuel gas generation device that can reduce the risk that normal operation will be disturbed due to blockage of a gas distribution nozzle.SOLUTION: There is provided a fuel gas generating device, comprising: a gasification furnace (1-b) for performing thermal decomposition of a raw material; a reforming furnace (1-a) for reforming a pyrolysis gas produced in the gasification furnace (1-b) to generate a fuel gas; and a combustion furnace (1-c) for combusting a pyrolysis residue transferred from the gasification furnace (1-b), wherein the reforming furnace (1-a) is installed above the gasification furnace (1-b), a gas distribution nozzle (1-h) for transferring the pyrolysis gas to the reforming furnace (1-a) is provided between the reforming furnace (1-a) and the gasification furnace (1-b), and the gasification furnace (1-b) is equipped with a fluidized sand bed (1-e) therein, and a raw material supply port (1-d) for supplying the raw material into the fluidized sand bed (1-e).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a fuel gas generating apparatus and a fuel gas generating method, and more particularly to a fuel gas generating apparatus for generating fuel gas from a raw material such as sewage sludge and recovering energy (e.g., electricity) from the fuel gas, and a fuel gas generating method carried out using the fuel gas generating apparatus. [Background technology]

[0002] Currently, the mainstream method for treating sewage sludge generated in Japan is to dehydrate the sewage sludge, convert the dehydrated sludge obtained by dehydrating the sewage sludge into incineration ash, and dispose of the incineration ash in a landfill. As an apparatus for incinerating the dehydrated sludge, an apparatus including a fluidized incinerator is generally used. Conventional incineration of dehydrated sludge is carried out by incinerating dehydrated sludge with a moisture content of 70 to 80% by weight under conditions of about 800 to 850°C using a fluidized incinerator in which, for example, silica sand is used as a fluidizing medium and combustion air is supplied as a fluidizing gas from the bottom of the fluidized bed.

[0003] In recent years, from the perspective of reducing greenhouse gas emissions, etc., plants have been put into practical use that have improved the efficiency of the method of supplying combustion air to fluidized incinerators, as well as plants that recover energy from sewage sludge by generating electricity by combining reducing the moisture content of the dewatered sludge to be incinerated with recovering boiler heat from the combustion exhaust gas.

[0004] Various methods and devices have been developed as methods and devices for burning sewage sludge and the like. For example, Patent Document 4 discloses a raw material supply device for a two-tower gasifier, which includes a combustion furnace for fluidizing and heating a fluidized medium, a fluidized bed gasifier in which the fluidized medium heated in the combustion furnace is separated from the combustion exhaust gas and introduced, and a solid raw material is introduced, a fluidized bed is formed with steam supplied from the lower part of the dispersion plate to gasify the solid raw material, and the gasification gas is taken out from a freeboard above the fluidized bed, and the unburned solid content in the fluidized bed gasifier is returned to the combustion furnace together with the fluidized medium to be burned, and the raw material supply device for a two-tower gasifier is characterized by having a two-shaft screw feeder that supplies solid raw materials to the inside of the fluidized bed of the fluidized bed gasifier. The two-tower gasifier described in Patent Document 4 is a facility that burns solid raw materials such as water-containing waste corresponding to sewage sludge and dewatered sludge to generate gasification gas (fuel gas). Patent Document 4 also lists coal, biomass, and waste plastic as the solid raw materials, in addition to water-containing waste.

[0005] Also, as the solid raw material, high-heat-generating sludge is known, which is obtained by replacing the moisture contained in sludge discharged from a sewage treatment device or the like with oil to increase the heat generation. The high-heat-generating sludge has low moisture and high heat generation, but may contain fine powder components such as fibrous materials. Patent Document 5 discloses a technique for avoiding a decrease in combustion efficiency due to the fine powder components when burning high-heat-generating sludge to generate fuel gas using a fluidized sand bed type sludge combustion furnace equipped with a fluidized sand bed inside. Specifically, Patent Document 5 discloses a technique for feeding the fine powder components of high-heat-generating sludge directly into the fluidized sand bed in a fluidized sand bed type sludge combustion furnace, and feeding aggregates, which are components other than the fine powder components of high-heat-generating sludge, from the top of the fluidized sand bed type sludge combustion furnace.

[0006] Patent Document 6 discloses a gasification method and a gasification apparatus that includes a gasification furnace that gasifies a raw material in the presence of circulating particles and a gasifying agent, a combustion furnace that introduces and burns char generated during gasification in the gasification furnace to heat the circulating particles, and a combustion gas from the combustion furnace is introduced into a separator to separate the exhaust gas and circulating particles, and the circulating particles are returned to the gasification furnace. The gasification method and the gasification apparatus are characterized in that the raw material is pyrolyzed by moving the circulating particles separated in the separator while mixing the raw material, and pyrolysis gas is extracted, and the pyrolysis residue is supplied to the gasification furnace to generate a reformed gasification gas by reforming gasification. The gasification method and the gasification apparatus described in Patent Document 6 are gasification methods and gasification apparatuses that use various organic raw materials such as biomass, coal, waste, petroleum residue, and heavy oil as raw materials. In short, in the gasification method and the gasification apparatus described in Patent Document 6, the residue obtained by pyrolyzing the raw material and extracting the pyrolysis gas is reformed and gasified in the gasification furnace to generate a reformed gasification gas (fuel gas).

[0007] Non-Patent Document 4 discloses a method for producing fuel gas from a raw material by using a chemical looping method comprising two reactors, a fuel reactor and an air reactor, in which biomass is used as a raw material, the raw material is oxidized (burned) in the presence of a metal oxide in the fuel reactor, and the metal oxide is reduced to obtain a metal, which is introduced into the air reactor, in which the metal is oxidized in the presence of air in the air reactor to obtain a metal oxide, and the metal oxide is introduced into the fuel reactor. The chemical looping method is a method in which a metal oxide and a metal are used as oxygen carriers and circulated through the fuel reactor and the air reactor.

[0008] Furthermore, in recent years, dewatered sludge has been dried to produce dried sludge with a moisture content of about 20% by weight, and the dried sludge is pyrolyzed and gasified in a low-oxygen atmosphere using the above-mentioned conventional method and apparatus for burning sewage sludge, etc., to produce CO, H 2 , C.H. 4Plants equipped with a system for producing fuel gas components such as sludge, coal, waste, petroleum residue, heavy oil, and other organic materials as raw materials instead of dewatered sludge, and for supplying the fuel gas components to a gas engine to generate power have also been put to practical use.

[0009] However, in the above system, the N from the air is added to the fuel gas. 2 Furthermore, in the above-mentioned system, at the outlet of furnaces such as fluidized bed gasifiers, fluidized sand bed sludge combustion furnaces, gasifiers and fuel reactors that produce gas from raw materials, the fuel gas condenses due to cooling, producing tar components that have a detrimental effect on gas engines, and this makes it necessary to treat the tar components by burning them at a high temperature of about 1000°C to decompose them. For these reasons, the above-mentioned system is designed to operate with a fuel gas with a calorific value of 4 MJ / m 3 However, due to the low energy recovery rate and the low power generation rate, there is still room for technological improvement in this system.

[0010] As an invention aimed at improving the above technology, for example, Patent Document 1 describes an apparatus including a three-tower circulating fluidized bed furnace and a gasification method using said apparatus as an invention for recovering energy from biomass with high efficiency. The apparatus described in Patent Document 1 is composed of a gasification furnace, a reformer furnace, a combustion furnace, and a riser. The gasification furnace gasifies the biomass raw material and produces "H 2 , CO, CO 2 and C.H. 4 The reforming furnace converts the fuel gas into "fuel gas containing tar and other main components such as coal, coal-fired coal, etc.," and "char (thermal cracking residue)." The reforming furnace reforms the tar in the fuel gas by the reforming function of the bed material, and further converts the tar in the fuel gas into H. 2 The combustion furnace is a furnace that burns char with air to generate a heat source, and heats a fluidized medium with the heat source. In the device and gasification method described in Patent Document 1, H in the fuel gas is converted into H, CO, etc., thereby increasing the amount of gas components produced in the fuel gas.2 Higher concentrations of CO 2 CaO is used as a fluidized medium for the main purpose of separation and recovery. Patent Document 3 discloses a tar reforming device and a tar reforming method capable of efficiently reforming tar only in one tower, i.e., in the reforming furnace, without circulating CaO, in order to solve the problem that in a normal three-tower circulating fluidized bed furnace as described in Patent Document 1, CaO, which functions as a catalyst in the reforming furnace, is degraded by circulating it through the other furnaces, that is, the gasification furnace and the combustion furnace. Specifically, Patent Document 3 discloses a tar reforming apparatus and a tar reforming method, the apparatus and method comprising: a reformer main body into which the pyrolysis gas from the pyrolysis furnace is introduced; a CaO particle storage section for storing calcium oxide particles that are not in contact with the pyrolysis gas; a particle introduction section for introducing the calcium oxide particles from the CaO particle storage section into the reformer main body; a fluidized bed containing the calcium oxide particles arranged in the reformer main body; and a gas introduction section for simultaneously or individually introducing the pyrolysis gas containing the tar and steam into the fluidized bed, the calcium oxide in the fluidized bed being heated to 850 to 950°C by the temperature of the pyrolysis gas of 800°C or higher and / or directly by a heating means provided in the reformer main body, and the tar contained in the pyrolysis gas is reformed by the steam at a temperature of 850 to 950°C in the fluidized bed due to the catalytic action of the calcium oxide particles.

[0011] Regarding the method of supplying the raw material, in general sewage sludge fluidized incinerators including a three-tower circulating fluidized bed incinerator, for example, as shown in Non-Patent Document 1, a method of supplying dewatered sludge from the top of the fluidized sand layer (top feed) is common. In addition, Non-Patent Document 2 and Patent Document 2 describe a method of supplying raw material sludge from above the seal pot section or loop seal section in a circulating fluidized incinerator, with the aim of improving the contact efficiency between the raw material sludge and the fluidized bed, thereby raising the temperature of the raw material sludge, and promoting the combustion reaction, and burning the raw material sludge while passing the raw material sludge through the inside of the fluidized bed or fluidized sand layer present in the seal pot section or loop seal section. In addition, Patent Document 1 illustrates the supply of raw material to a gasifier in a three-tower circulating fluidized bed incinerator, but does not clearly show the supply position of the raw material.

[0012] Furthermore, Non-Patent Document 3 describes a three-column circulating fluidized bed device that uses ilmenite as a fluidizing medium, and produces high-concentration CO from coal through the oxidation-reduction reaction of the Fe component contained in the ilmenite. 2 On the other hand, in the method described in Non-Patent Document 3, coal as a raw material is supplied to a fuel reactor at the lower stage. In addition, in the method described in Non-Patent Document 3, in order to promote the reaction between ilmenite and coal in the reactor, the raw material coal is fed by a carrier gas, and CO 2 gas is fed as a carrier gas at a supply flow rate of 7.6 m / s from a position 200 mm above a gas dispersion plate installed at the bottom of the fuel reactor using a screw feeder. 2 Together with this, it is fed to the ilmenite fluidized bed. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] JP 2014-240472 A [Patent Document 2] JP 2001-235128 A [Patent Document 3] JP 2019-196414 A [Patent Document 4] JP 2009-215426 A [Patent Document 5] Japanese Patent Application Publication No. 62-284117 [Patent Document 6] JP 2011-026413 A [Non-patent literature]

[0014] [Non-Patent Document 1] Fluidized Incineration System | Solutions | Metawater Co., Ltd. (metawater.co.jp), Internet<URL:hhttps: / / www.metawater.co.jp / solution / product / sewer / flow_furnace / > [Non-Patent Document 2] Hiroshi Miyamoto and 5 others, "Development of Circulating Fluidized Bed Incinerator for Sewage Sludge", Kobe Steel Technical Review, vol. 51 No. 2 (Sep. 2001) [Non-Patent Document 3] Andreas Thon et al., "Operational experience with a system of coupled fluidized beds for chemical looping combustion of solid fuels using ilmenite as oxygen carrier", Applied Energy, 118. (2014), pp.309-317 [Non-Patent Document 4] Ivan Gogolev et al., "Commissioning, performance benchmarking, and investigation of alkali emissions in a 10 kWth solid fuel chemical looping combustion pilot", Fuel, 287, (2021), 119530 Summary of the Invention [Problem to be solved by the invention]

[0015] The fuel gas generating apparatus and method using the above-mentioned conventional three-tower circulating fluidized bed furnace had a problem that it may not be able to operate normally after long-term operation. The following reasons are considered to be the causes of this problem.

[0016] Using a conventional three-tower circulating fluidized bed furnace, 2 In the method for producing fuel gas mainly composed of CO, CO, etc., as described above, the raw material is generally supplied from the top of the fluidized sand layer (top feed) in the gasification furnace. Here, as the raw material for the conventional method for producing fuel gas, a raw material having a high volatile content such as sewage sludge or a raw material having a very fast gasification reaction rate such as biomass fuel is generally used. In this case, since the raw material is top-fed in the conventional method for producing fuel gas, the gasification reaction of the raw material proceeds before the raw material is mixed with the fluidized sand layer, and a "fuel gas containing a large amount of tar" and "char" are generated from the raw material. In the method for producing fuel gas using a three-tower circulating fluidized bed furnace, one of the features is that the char generated in the gasification furnace is taken into the fluidized sand layer of the gasification furnace and discharged to the combustion furnace, and used as a combustion heat source. However, when the raw material is supplied to the gasification furnace by top feed, the char is not taken into the fluidized sand layer, and the amount of char scattered upward by the fluidized gas and pyrolysis gas increases. As a result, char adheres to the gas dispersion nozzle of the reformer installed above the gasifier, obstructing the gas flow and preventing normal operation.

[0017] In addition, in a typical fluidized incinerator for sewage sludge, such as the fluidized incinerator described in Non-Patent Document 1, a freeboard section is provided above the sand layer, so that scattering of incineration ash and the like can be minimized. However, in an apparatus equipped with a three-tower circulating fluidized bed furnace, since the reformer furnace is installed above the gasifier, if the length of the freeboard section is increased to reduce char scattering in the gasifier, the apparatus will become larger. Here, there is a practical limit to how large the apparatus can be. Therefore, in a method for producing fuel gas using an apparatus equipped with a three-tower circulating fluidized bed furnace, it is considered difficult to solve the problem of normal operation being impossible due to clogging of the gas dispersion nozzle by providing the freeboard section.

[0018] In addition, in the method described in Non-Patent Document 3, the carrier gas is supplied to the gasification furnace using a screw feeder at a supply flow rate of 7.6 m / s, so that a large amount of carrier gas is supplied to the gasification furnace together with the raw material. However, when the supply flow rate of the carrier gas is high, the scattering of particles of char and bed material from the furnace increases, so that the freeboard height needs to be increased and the size of the device needs to be increased. In this case, there is a possibility that disadvantages will occur in terms of thermal efficiency, such as an increase in the size of the device and an increase in the amount of heat dissipation. In order to reduce the size of the device and avoid the above disadvantages, it is necessary to reduce the amount of carrier gas as much as possible. In other words, the method described in Non-Patent Document 3 has a problem that the supply flow rate of the carrier gas is high, which may cause disadvantages in terms of thermal efficiency.

[0019] An object of the present disclosure is to provide a fuel gas generation apparatus and a fuel gas generation method that can reduce the possibility that normal operation will be hindered due to clogging of the gas dispersion nozzle. [Means for solving the problem]

[0020] A fuel gas generation apparatus according to one embodiment of the present disclosure is a fuel gas generation apparatus comprising a gasification furnace for pyrolyzing a feedstock, a reforming furnace for reforming the pyrolysis gas produced in the gasification furnace to generate fuel gas, and a combustion furnace for burning the pyrolysis residue transferred from the gasification furnace, wherein the reforming furnace is installed above the gasification furnace, and a gas dispersion nozzle for transferring the pyrolysis gas to the reforming furnace is provided between the reforming furnace and the gasification furnace, and the gasification furnace has a fluidized sand layer therein and a feedstock supply port for supplying the feedstock into the fluidized sand layer.

[0021] A fuel gas generation method according to one embodiment of the present disclosure is a fuel gas generation method carried out using a fuel gas generation apparatus according to one embodiment of the present disclosure, and includes a raw material supplying process of supplying the raw material into the fluidized sand bed through the raw material supply port, a pyrolysis gas generation process of causing pyrolysis of the raw material inside the fluidized sand bed to proceed, and a reforming process of supplying the pyrolysis gas obtained in the pyrolysis gas generation process to the reforming furnace and reforming the pyrolysis gas to generate fuel gas. Effect of the Invention

[0022] According to an embodiment of the present disclosure, it is possible to provide a fuel gas generation apparatus and a fuel gas generation method that can reduce the possibility that normal operation will be hindered due to clogging of the gas dispersion nozzle. [Brief description of the drawings]

[0023] [Figure 1] 1 is a diagram illustrating a configuration of a fuel gas generating device according to an embodiment of the present disclosure. [Diagram 2] 1 is a diagram showing the structure of a gasification furnace and a reformer furnace in a fuel gas generation device according to an embodiment of the present disclosure. [Diagram 3] FIG. 13 is a diagram showing the structure of a gasification furnace and a reformer furnace in a fuel gas generation device according to another embodiment of the present disclosure. [Figure 4] FIG. 2 is a diagram showing the structure of a standpipe and a gas distribution plate of a reformer in a fuel gas generating apparatus according to an embodiment of the present disclosure. [Diagram 5] 1 is a graph showing the measurement results of reformer differential pressure in Example 1-1 and Comparative Example 1. [Figure 6] 4 is a graph showing the measurement results of the reformer differential pressure in Example 1-2. [Figure 7] 1 is an image of the gas dispersion plate of the reformer after the test in Comparative Example 1, taken from below the gas dispersion plate. [Figure 8] 4 is an image of the gas dispersion plate of the reformer after the test in Example 1, taken from below the gas dispersion plate. [Figure 9] 11 is a graph showing the change over time in the CO2 concentration in the fuel gas and the reformer differential pressure in Example 2. [Figure 10] FIG. 1 is a diagram illustrating a configuration of a fuel gas generating method according to an embodiment (embodiment 1-1) of the present disclosure. [Figure 11] FIG. 1 is a diagram illustrating a configuration of a fuel gas generating method according to an embodiment (embodiment 1-2) of the present disclosure. [Figure 12] FIG. 1 is a diagram illustrating a configuration of a fuel gas generating method according to an embodiment (embodiment 1 to embodiment 3) of the present disclosure. [Figure 13] FIG. 4 is a diagram illustrating a configuration of a fuel gas generating method according to an embodiment (embodiment 2) of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an example of an embodiment of the present disclosure will be described in detail, but the present disclosure is not limited thereto. The contents described in each of the following items can be appropriately applied to other items. The present disclosure is not limited to the following embodiments, and various modifications are possible within the scope of the claims. Therefore, an embodiment obtained by appropriately combining the technical means disclosed in each of the different embodiments is also included in the technical scope of the present disclosure.

[0025] Unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more, B or less." All academic and patent documents described in this specification are incorporated herein by reference.

[0026] [Embodiment A: Fuel gas generating device] A fuel gas generation apparatus according to one embodiment of the present disclosure (hereinafter referred to as "the fuel gas generation apparatus of the present disclosure") is a fuel gas generation apparatus comprising a gasification furnace for pyrolyzing a raw material, a reforming furnace for reforming the pyrolysis gas produced in the gasification furnace to generate fuel gas, and a combustion furnace for burning the pyrolysis residue transferred from the gasification furnace, wherein the reforming furnace is installed above the gasification furnace, and a gas dispersion nozzle for transferring the pyrolysis gas to the reforming furnace is provided between the reforming furnace and the gasification furnace, and the gasification furnace has a fluidized sand layer therein and a raw material supply port for supplying the raw material into the fluidized sand layer.

[0027] The fuel gas generating apparatus of the present disclosure may be an apparatus including a three-tower circulating fluidized bed furnace. For example, as shown in FIG. 1, the fuel gas generating apparatus of the present disclosure further includes a gasifier 1-b, a reformer 1-a installed above the gasifier 1-b, a combustion furnace 1-c, a gas dispersion nozzle 1-h connecting the gasifier 1-b and the reformer 1-a, a device 1-m for supplying (circulating) fluidized sand (fluidized medium) from the gasifier to the combustion furnace, a device 1-n for supplying fluidized sand from the combustion furnace to the reformer, and a standpipe 1-f for supplying fluidized sand from the reformer to the gasifier. Also, as shown in FIG. 1, the gasifier 1-b in the fuel gas generating apparatus of the present disclosure includes a fluidized sand layer 1-e therein and a raw material supply port 1-d for supplying the raw material to the inside of the fluidized sand layer. Furthermore, as shown in FIG. 1, a raw material insertion pipe 1-o may be connected to the raw material supply port 1-d. In addition, as shown in FIG. 1, the reformer 1-a and the combustion furnace 1-c in the fuel gas generation apparatus of the present disclosure may also be provided with a fluidized sand layer 1-e therein.

[0028] The fuel gas generating apparatus of the present disclosure further includes a configuration in which the reformer and the combustion furnace are connected via an upper loop seal (hereinafter, "loop seal" will be referred to as "LS"), the gasification furnace and the combustion furnace are connected via a lower LS, and a mechanism for supplying gas to the upper LS and the lower LS is provided. Specifically, in the fuel gas generating apparatus of the present disclosure, for example, as shown in FIG. 1, a device 1-n for supplying fluidized sand from the combustion furnace to the reformer includes the upper LS1-i, and a device 1-m for supplying fluidized sand from the gasification furnace to the combustion furnace includes the lower LS1-j. The upper LS and the lower LS are provided with a mechanism for supplying gas therein, and have a function for reducing the possibility of fluidized sand or the like flowing backward by supplying gas therein. Therefore, by providing the upper LS and the lower LS, the possibility of fluidized sand or the like flowing backward can be reduced and fluidized sand can be suitably circulated inside the apparatus in the fuel gas generating method using the fuel gas generating apparatus of the present disclosure. In addition, by providing the upper portion LS, in the fuel gas generation method using the fuel gas generation apparatus of the present disclosure, the generated fuel gas and the combustion exhaust gas can be suitably separated and recovered. The gas is not particularly limited as long as it does not affect the fluidized sand and the char, and examples thereof include nitrogen (N 2 ) gas, water vapor, a mixture of water vapor and a part of the obtained fuel gas, and a part of the obtained fuel gas. The gas supply method may be, for example, a method of supplying gas from two places in each of the upper LS1-i and the lower LS1-j, as shown in gas (a) and gas (b) in FIG. 1. The mechanism for supplying gas to the inside of the upper LS and the lower LS is not particularly limited, and a known mechanism can be adopted. When water vapor is used as the gas, the obtained fuel gas may be mixed with water vapor. In that case, only the water vapor can be condensed and collected by cooling the obtained fuel gas and water vapor, and a decrease in the calorific value of the fuel gas due to the mixing of water vapor can be prevented.

[0029] In the fuel gas generating apparatus of the present disclosure, as shown in FIG. 1, a char outlet 1-r in the gasification furnace 1-b described later and a char supply port in the combustion furnace 1-c described later are connected via a device 1-m for supplying fluidized sand from the gasification furnace to the combustion furnace. Thus, through the device 1-m for supplying fluidized sand from the gasification furnace to the combustion furnace, the fluidized sand flows in the gasification furnace 1-b together with the char generated in the gasification furnace 1-b, and the fluidized sand that overflows from the gasification furnace 1-b is supplied to the combustion furnace 1-c. In addition, through a device 1-n for supplying fluidized sand from the combustion furnace to the reformer, a discharge port for the fluidized sand and combustion exhaust gas in the combustion furnace 1-c described later and a fluidized sand supply port in the reformer 1-a described later are connected. Thus, through the device 1-n for connecting the combustion furnace and the reformer, the fluidized sand that flows in the combustion furnace 1-c and overflows from the combustion furnace 1-c is supplied to the reformer 1-a. Furthermore, the fluidized sand that has flowed within the reformer 1-a and overflowed from the reformer 1-a is supplied to the gasifier 1-b through a standpipe 1-f, which is a device for supplying fluidized sand from the reformer to the gasifier. From the above, when fuel gas is generated using the fuel gas generation device disclosed herein, the fluidized sand circulates through the gasifier, the reformer, and the combustion furnace.

[0030] As shown in FIG. 1, the device 1-m for supplying fluidized sand from the gasifier 1-b to the combustion furnace 1-c may be provided with a device for supplying gas (lower intermediate gas) from the gasifier to the combustion furnace. Similarly, the device 1-n for connecting the combustion furnace and the reformer may be provided with a device for supplying gas (upper intermediate gas) from the combustion furnace 1-c to the reformer 1-a. The gas functions as a carrier gas for supplying the fluidized sand. Therefore, by providing the device for supplying the gas, the fluidized sand can be circulated more suitably. The gas is not particularly limited as long as it does not affect the fluidized sand and char, and for example, the same gas as that supplied to the lower LS and the upper LS can be used.

[0031] The portion other than the lower portion LS and the upper portion LS in the device for supplying fluidized sand from the gasifier to the combustion furnace and the device for supplying fluidized sand from the combustion furnace to the reformer may be, for example, a pipe (piping). The device for supplying fluidized sand from the gasifier to the combustion furnace may also be a device for supplying char from the gasifier to the combustion furnace. As shown in FIG. 1, the device for supplying fluidized sand from the combustion furnace 1-c to the reformer 1-a may include a riser 1-k and a cyclone 1-l. The device for supplying fluidized sand from the reformer to the gasifier is not particularly limited, and may be, for example, a standpipe 1-f shown in FIG. 1. The standpipe 1-f may be provided on a gas distribution plate 1-g installed between the top of the gasifier 1-b and the bottom of the reformer 1-a together with a gas distribution nozzle 1-h, as shown in FIGS. 1 to 4.

[0032] The fuel gas generation apparatus of the present disclosure may include a device for recovering the combustion exhaust gas, and as shown in Fig. 1, the device for recovering the combustion exhaust gas 15 may be connected to the cyclone 1-1. Furthermore, the fuel gas generation apparatus of the present disclosure may appropriately include a heating device for adjusting the internal temperature of each component. Examples of the heating device include a heater.

[0033] <Gasification furnace> The gasification furnace is a furnace for pyrolyzing a raw material, and is provided with a fluidized sand bed therein and a raw material supply port for supplying the raw material into the fluidized sand bed. Here, the raw material is not particularly limited as long as it is a material that can be used as a raw material for fuel gas, and is, for example, various organic raw materials such as sewage sludge (dewatered sludge, dried sludge), biomass, coal, waste, petroleum residue, and heavy oil. In addition, the fluidized sand (fluidizing medium) constituting the fluidized sand bed is not particularly limited, and may be a material used as a fluidizing medium in an apparatus for generating combustion gas from the raw material. The fluidized sand bed may include, for example, one or more types selected from the group consisting of olivine, alumina, and calcined lime. The fluidized sand functions, for example, as a fluidizing medium such as a medium for fluidizing char from a gasification furnace to a combustion furnace, and as a catalyst for a reaction for further decomposing tar generated by pyrolysis of the raw material to generate combustion gas.

[0034] The structure of the gasifier may have, for example, the structure shown in the gasifier 1-b (lower furnace) in FIG. 2. The fluidized sand circulates through the gasifier 1-b, the reformer 1-a, and the combustion furnace, as shown by the dashed lines and arrows in FIG. 2. In detail, the fluidized sand overflowing from the fluidized sand layer 1-e in the gasifier 1-b moves (circulates) to the combustion furnace through the lower LS1-j. Then, the fluidized sand moving from the combustion furnace moves (circulates) to the reformer 1-a through the upper LS1-i, and joins the fluidized sand layer 1-e in the reformer 1-a. Then, the fluidized sand overflowing from the fluidized sand layer 1-e in the reformer 1-a moves (circulates) to the gasifier 1-b through the standpipe 1-f, and joins the fluidized sand layer 1-e in the gasifier 1-b. Therefore, the same fluidized sand as that in the gasifier 1-b may be used for the fluidized sand in the reformer 1-a and the combustion furnace. Here, olivine is a natural ore whose main components are magnesium, silica, iron, etc. The iron contained in olivine is reduced by the fuel gas generated in the gasifier and the reformer, and is converted into reduced iron having a tar reforming function. The reduced iron then reforms the tar components in the fuel gas to produce H. 2 , CO, etc., thereby increasing the amount of fuel gas produced. Furthermore, when the reduced olivine is oxidized in the combustion furnace, the heat of the oxidation reaction can be used to combust char. Furthermore, a portion of the fluidized sand can be discharged after being mixed with the combustion residue (incineration ash) produced in the combustion furnace. In view of this, it is preferable that the fluidized sand is inexpensive. Furthermore, natural minerals such as olivine are inexpensive compared to artificial catalysts. For these reasons, it is preferable to use olivine as the fluidized sand.

[0035] The gasification furnace is connected to a fluidizing gas supply unit for the gasification furnace, and fluidizing gas is supplied into the fluidized sand bed. In addition, as a thermal decomposition reaction in the gasification furnace, water vapor (H 2The reaction utilizes a reaction in which the raw material is pyrolyzed in the presence of nitrogen (N O). Therefore, the fluidizing gas may usually be steam for gasification 8 as shown in FIG. 1. The fluidizing gas may also be a gas containing steam, for example, nitrogen (N 2 ) and steam. The fluidizing gas is supplied from the bottom of the gasification furnace 1-b, which is a position different from the raw material supply port 1-d, as shown in FIG. 1, so as not to interfere with the supply of the raw material. As the fluidizing gas supply unit for the gasification furnace, a fluidizing gas supply unit that can be generally used as a fluidizing gas supply unit in a fuel gas generation device can be adopted.

[0036] In the gasification furnace, pyrolysis is carried out according to the following reaction, and a combustible gas (pyrolysis gas) is generated. Here, since the raw material is an organic matter, it may contain carbon (C), hydrogen (H), oxygen (O), nitrogen (N), etc. That is, the raw material is pyrolyzed in the presence of water vapor according to the reaction shown in the following formula (1), and is converted into pyrolysis gas and pyrolysis residue (char). The pyrolysis gas contains hydrogen "H 2 ", carbon monoxide "CO", carbon dioxide "CO 2 ", and ammonia "NH 3 " and methane "CH 4 ", and hydrocarbon gases and tar-containing hydrocarbon gases "C m H n The pyrolysis residue contains charcoal and ash.

[0037] Raw materials (C,H,O,N)+H 2 O → pyrolysis gas (H 2 ,CO,CO 2 ,C m H n ,NH 3 )+C(charcoal)+ash content…(1) Here, the ash content is a compound containing P, Si, Al, Fe, Mg, Ca, Na, K, etc., derived from impurities in the raw material.

[0038] In addition, a portion of the charcoal reacts with water vapor and is converted into carbon dioxide and hydrogen, as shown in the following formula (2).

[0039] C(charcoal)+2H 2 O→CO 2 +2H 2 …(2) Furthermore, the carbon monoxide contained in the pyrolysis gas reacts with water vapor and is converted into carbon dioxide, as shown in the following formula (3).

[0040] CO+H 2 O→CO 2 +H 2 …(3) Here, in the fuel gas generating apparatus of the present disclosure, the gasification furnace is provided with a raw material supply port for supplying the raw material into the inside of the fluidized sand bed, and the raw material is supplied into the inside of the fluidized sand bed, and the thermal decomposition reaction of the raw material proceeds inside the fluidized sand bed. Therefore, the generated char is taken into the fluidized sand bed without scattering upward, and is discharged to the combustion furnace. In addition, the fuel gas generating apparatus of the present disclosure is provided with a raw material supply port for supplying the raw material into the inside of the fluidized sand bed, so that the raw material can be supplied to the gasification furnace even when the supply amount of the carrier gas is reduced compared to the conventional fuel gas generating method. Therefore, it is possible to reduce the need to increase the size of the apparatus due to the supply of a large amount of carrier gas to the gasification furnace. From the above, the fuel gas generating apparatus of the present disclosure has an effect of reducing the possibility that normal operation is hindered due to the clogging of the gas dispersion nozzle. In addition, the fuel gas generating apparatus of the present disclosure also has an effect of enabling the apparatus to be made smaller.

[0041] Here, providing a raw material supply port for supplying the raw material into the fluidized sand bed means providing a raw material supply port 1-d at a location on the side of the gasifier 1-b where the fluidized sand bed 1-e filled inside the gasifier 1-b is present (for example, at a location in contact with the fluidized sand bed filled inside the gasifier) ​​as shown in Fig. 2. When the height of the fluidized sand bed when the fluidized sand bed is filled in the gasifier is taken as 100%, the raw material supply port is preferably provided at a position 30% to 70% from the top of the fluidized sand bed. This specifically means that the ratio calculated by the following formula using the height of the fluidized sand bed: H0 and the distance from the top of the fluidized sand bed to the position (height) where the raw material supply port is provided: H1, as shown in Fig. 2, is preferably 30% to 70%. (H1 / H0) x 100 (unit: %) The height H0 of the fluidized sand bed is determined by the height of the char discharge port 1-r, which discharges pyrolysis residue from the gasifier 1-b in the direction of the combustion furnace 1-c in Fig. 2. Therefore, H0 can also be defined as the height from the bottom surface of the gasifier 1-b to the char discharge port 1-r.

[0042] The raw material supply inlet is located at a position that is 30% to 70% from the top of the fluidized sand bed, in other words, the raw material supply inlet is located at a position that is 30% to 70% from the char discharge outlet 1-r toward the bottom of the gasification furnace 1-b, which makes it easier for the generated char to be incorporated into the fluidized sand bed and suppresses the char from scattering upward.

[0043] The form of supplying the raw material from the raw material supply port to the inside of the fluidized sand bed is not particularly limited, and for example, a form in which a device for transporting the raw material is connected to the raw material supply port can be mentioned. Examples of the device for transporting the raw material include a raw material insertion pipe and a belt conveyor, and preferably a raw material insertion pipe. In addition, as shown by the arrow in FIG. 2, a form in which the raw material 13 is introduced from the raw material supply feeder 1-p through the raw material supply valve 1-q into the raw material insertion pipe 1-o, passes through the raw material insertion pipe 1-o, and is supplied to the inside of the fluidized sand bed 1-e in the gasification furnace 1-b through the raw material supply port 1-d connected to the raw material insertion pipe 1-o can be mentioned.

[0044] When a raw material insertion pipe is connected to the raw material supply port, the raw material insertion pipe is installed in the gasification furnace at an angle of preferably 30° or more, more preferably 35° or more, and even more preferably 40° or more with respect to the horizontal direction. By installing the raw material insertion pipe in the gasification furnace at an angle of 30° or more with respect to the horizontal direction, the possibility of a raw material supply failure caused by accumulation of raw material inside the raw material insertion pipe can be suitably reduced. In addition, the raw material insertion pipe is installed in the gasification furnace at an angle of preferably 60° or less, more preferably 55° or less, and even more preferably 50° or less with respect to the horizontal direction. By installing the raw material insertion pipe in the gasification furnace at an angle of 60° or less with respect to the horizontal direction, the horizontal distance between the raw material supply unit and the gasification furnace is increased, so that the possibility of a decrease in safety due to a temperature rise of a raw material supply hopper constituting the raw material supply unit and / or a decrease in workability during maintenance and inspection due to the installation space can be suitably reduced. Furthermore, from the viewpoint of reducing the possibility of the occurrence of the above-mentioned malfunction of the raw material supply, the deterioration of safety, and the deterioration of the workability during maintenance and inspection, it is most preferable that the raw material insertion pipe is installed in the gasification furnace at an angle of 45° with respect to the horizontal direction. Specifically, the angle of the raw material insertion pipe with respect to the horizontal direction is the angle represented by "θ" in FIG. 2.

[0045] In the fuel gas generating apparatus of the present disclosure, the raw material supplying unit may be a raw material supplying unit that can be generally used as a raw material supplying unit in a fuel gas generating apparatus. Examples of the raw material supplying unit include a raw material supply feeder 1-p and a raw material supply valve 1-q as shown in FIG. 2. The raw material supplying unit may be directly connected to the raw material supplying port, or, when a device for transporting raw material is connected to the raw material supplying port, may be connected to the opposite side of the raw material supplying port of the device for transporting raw material. The raw material supplied from the raw material supplying port is supplied directly to the raw material supplying port, or is supplied to the raw material supplying port through the device for transporting the raw material.

[0046] The gasifier may include a char outlet connected to a device for supplying fluidized sand from the gasifier to a combustion furnace. Char is discharged from the char outlet together with fluidized sand that has fluidized and overflowed from the gasifier to the combustion furnace. Specifically, as shown in FIG. 2, the char outlet 1-r is an outlet shown to be connected to the lower portion LS1-j.

[0047] The gasification furnace may be provided with a fluidized sand supply port connected to a device for supplying new fluidized sand. By providing the fluidized sand supply port, fluidized sand can be appropriately supplied to the gasification furnace before, during, and / or after the fuel gas production method using the fuel gas production apparatus of the present disclosure is carried out.

[0048] <Reforming furnace> The reformer is disposed above the gasifier, and is a furnace for reforming the pyrolysis gas produced in the gasifier to produce fuel gas.

[0049] The reaction for reforming the pyrolysis gas is usually steam reforming. Here, the fluidizing gas supplied to the gasification furnace may contain steam. Therefore, in the fuel gas generation method using the fuel gas generation apparatus of the present disclosure, the pyrolysis gas supplied from the gasification furnace to the reforming furnace contains unreacted steam, and the pyrolysis gas functions as a fluidizing gas to fluidize the fluidized sand in the reforming furnace. The reforming furnace may be connected to a supply unit that supplies another fluidizing gas containing steam to the reforming furnace. The fluidizing gas supply unit that supplies the other fluidizing gas is not particularly limited, and a fluidizing gas supply unit that can be generally used as a fluidizing gas supply unit in a fuel gas generation apparatus may be adopted.

[0050] Specifically, in the reformer, methane (CH 4 ", and hydrocarbon gases and tar-containing hydrocarbon gases "C m H n " is reformed into hydrogen and carbon dioxide. Thus, the fuel gas generated in the reformer contains hydrogen, carbon monoxide, carbon dioxide, and methane contained in the pyrolysis gas, as well as hydrogen and carbon dioxide generated by the reforming, and nitrogen and water vapor constituting the fluidizing gas. C m H n +H 2 O→H 2 +CO 2 …(4) The structure of the reformer may be, for example, the structure shown in reformer 1-a (upper furnace) in Fig. 2. As shown in Fig. 2, the reformer 1-a includes a fluidized sand layer 1-e, similar to the gasifier 1-b. The fluidized sand (fluidized medium) constituting the fluidized sand layer 1-e functions as a reaction catalyst for the reforming.

[0051] The reformer may have a fuel gas outlet for discharging the generated fuel gas. Since the generated fuel gas usually moves upward in the reformer, the position where the fuel gas outlet is provided is the upper part of the reformer, more preferably the top part. The fuel gas outlet may be connected to a tank for recovering and storing the fuel gas, and a gas engine generator for generating electricity using the fuel gas. A gas purification facility may be provided between the reformer and the tank and the gas engine generator. When the fuel gas outlet is connected to the tank, the generated fuel gas can be stored in the tank and used at a later date in the fuel gas generation method using the combustion gas generation device of the present disclosure. When the fuel gas outlet is connected to the gas engine generator, the generated fuel gas can be used to operate the gas engine generator to generate electricity in the fuel gas generation method using the combustion gas generation device of the present disclosure.

[0052] The gas purification facility may, for example, convert CO contained in the fuel gas into CO 2 a conversion section for converting the converted gas into H 2 and CO 2 and C.H. 4 The gas purification equipment may include an off-gas separation unit that separates the fuel gas from the purified hydrogen and the off-gas (CH 4 and CO 2The gas purification equipment may be connected to a combustion furnace and / or a carrier gas supply unit described later. Specifically, the combustion gas generation apparatus of the present disclosure may include a supply pipe to an off-gas carrier gas supply unit that supplies a part of the off-gas to the carrier gas supply unit described later as at least a part of the carrier gas, and / or a supply pipe to an off-gas combustion furnace that supplies another part of the off-gas to the combustion furnace. When the combustion gas generation apparatus of the present disclosure includes a supply pipe to the off-gas carrier gas supply unit, in the fuel gas generation method using the combustion gas generation apparatus of the present disclosure, a part of the off-gas is supplied to the carrier gas supply unit and used as at least a part of the carrier gas. In addition, a part of the off-gas may be supplied to the combustion furnace as a heat source. In addition, when the combustion gas generation apparatus of the present disclosure includes a supply pipe to the off-gas combustion furnace, in the fuel gas generation method using the combustion gas generation apparatus of the present disclosure, another part of the off-gas is supplied to the combustion furnace as a heat source. As a result, when fuel gas is generated using the combustion gas generation device disclosed herein, the amount of carrier gas supplied from the outside and the amount of heat supplied from the outside are reduced, and as a result, the energy required for fuel gas generation can be reduced.

[0053] The reformer includes a fluidized sand supply port connected to a device that supplies fluidized sand from the combustion furnace to the reformer. The fluidized sand supply port is, for example, a port shown to be connected to the upper portion LS1-i in FIG. 2. Thus, fluidized sand is supplied to the reformer from the combustion furnace. The fluidized sand supply port may also be separately connected to a device that supplies new fluidized sand separate from the fluidized sand supplied from the combustion furnace. In this case, new fluidized sand can be supplied to the reformer as appropriate before, during, and / or after the fuel gas generation method using the fuel gas generation apparatus of the present disclosure is performed.

[0054] <Gas dispersion nozzle> The gas dispersion nozzle is a nozzle provided between the reformer and the gasifier for dispersing the pyrolysis gas and transferring it from the gasifier to the reformer. The form of the gas dispersion nozzle is not particularly limited as long as it can disperse the pyrolysis gas and transfer it from the gasifier to the reformer. As an example of the form of the gas dispersion nozzle, as shown in Figs. 1 to 4, a gas dispersion plate 1-g is provided between the top of the gasifier 1-b and the bottom of the reformer 1-a, and is provided with a standpipe 1-f as a device for supplying fluidized sand from the reformer 1-a to the gasifier 1-b, and a plurality of gas dispersion nozzles 1-h are provided on the gas dispersion plate 1-g. The pyrolysis gas is supplied from the gasifier 1-b to the reformer 1-a through each of the plurality of gas dispersion nozzles 1-h by the gas dispersion plate 1-g.

[0055] As shown in Fig. 2, the standpipe 1-f is preferably a pipe having one end located inside the fluidized sand layer 1-e in the gasifier 1-b and the other end located above the fluidized sand layer 1-e in the reformer 1-a. As a result, before and after the fuel gas generation method using the fuel gas generation apparatus of the present disclosure is performed, the fluidized medium (fluidized sand) constituting the fluidized sand layer 1-e in the reformer 1-a does not enter the standpipe 1-f. On the other hand, during the fuel gas generation method, the fluidized medium that has flowed and overflowed from the reformer 1-a is preferably supplied to the fluidized sand layer 1-e in the gasifier 1-b through the standpipe 1-f.

[0056] <Combustion furnace> The combustion furnace is a furnace for combusting the pyrolysis residue (char) transferred from the gasification furnace. In the combustion furnace, the char supplied together with the fluidized sand from the gasification furnace is combusted to generate combustion exhaust gas. The combustion furnace is provided with a char supply port through which the char is supplied.

[0057] The combustion furnace is usually connected to a fluidizing gas supply unit for the combustion furnace, and an oxygen-containing gas (e.g., air) is supplied as the fluidizing gas. As the fluidizing gas supply unit for the combustion furnace, a fluidizing gas supply unit that can be generally used as a fluidizing gas supply unit in a fuel gas generating device can be adopted. For example, as shown in FIG. 1, in the combustion furnace 1-c, the oxygen-containing gas 7 is supplied from the bottom of the combustion furnace 1-c.

[0058] The fluidized gas supply unit for the combustion furnace is connected to the outside of the fuel gas generating apparatus of the present disclosure, and a gas containing oxygen is supplied to the combustion furnace from the outside. In addition, the combustion furnace may be supplied with a combustion gas serving as a heat source. The combustion gas may be supplied from the outside, or a part of the fuel gas or the off-gas may be supplied to the combustion furnace as the combustion gas. As a device for supplying the combustion gas from the outside, a device generally used as a device for taking in air from the outside can be used. As a device for supplying a part of the fuel gas or the off-gas as the combustion gas, for example, the above-mentioned off-gas supply pipe to the combustion furnace and a pipe for supplying a part of the fuel gas to the combustion furnace may be used.

[0059] Specifically, in the combustion furnace, char is burned mainly by the reaction shown in the following formula (5) to generate a combustion exhaust gas. That is, charcoal contained in the pyrolysis solid product is burned by air or an oxygen-containing gas to produce carbon dioxide. Therefore, the combustion exhaust gas may contain, in addition to carbon dioxide, oxygen originating from the fluidizing gas in the combustion furnace and nitrogen originating from the fluidizing gas in the gasification furnace.

[0060] C(charcoal)+O 2 →CO 2 …(5) The combustion furnace may be provided with an auxiliary fuel supply port for supplying auxiliary fuel to the combustion furnace. The form of the auxiliary fuel supply port is not particularly limited as long as the auxiliary fuel can be supplied to the combustion furnace, and for example, an embodiment disclosed in JP 2020-128325 A in which dried sludge is supplied as auxiliary fuel from a drying device to a fuel device (combustion furnace) through a heat source dried sludge supply path can be mentioned. Among the fuel gas generation devices disclosed herein, a fuel gas generation method using a device including a combustion furnace equipped with the auxiliary fuel supply port may include an auxiliary fuel supply step of supplying the auxiliary fuel to the combustion furnace.

[0061] The combustion furnace may have a combustion exhaust gas outlet for discharging the combustion exhaust gas. Since the generated fuel gas usually moves upward in the reformer, the position where the combustion exhaust gas outlet is provided is at the top of the reformer, more preferably at the top. Specifically, for example, as shown in FIG. 1, the combustion exhaust gas outlet is an opening located at the top of the combustion furnace 1-c and connected to a riser 1-k in the combustion furnace 1-c.

[0062] Residues may be generated when the char is combusted in the combustion furnace. Therefore, the combustion furnace may be provided with a disposal port for disposing of the residues. When disposing of the residues, the fluidized sand may be disposed of together.

[0063] The char supply port of the combustion furnace may be connected to a device for supplying new fluidized sand separate from the fluidized sand supplied from the gasification furnace. In this case, new fluidized sand can be appropriately supplied to the combustion furnace before, during, and / or after the fuel gas production method using the fuel gas production apparatus of the present disclosure is carried out.

[0064] <Carrier gas supply unit> The fuel gas generating apparatus of the present disclosure may include a carrier gas supplying unit that supplies a carrier gas to the raw material supplied to the inside of the fluidized sand layer in the gasification furnace. The carrier gas supplying unit is connected to the raw material supply port or a device that transports raw material to the raw material supply port, and has a function of supplying the carrier gas together with the raw material to the gasification furnace. The carrier gas supplying unit is not particularly limited as long as it has the above function, and a carrier gas supplying unit that is generally used in fuel gas generating apparatuses can be adopted. The carrier gas supplying unit eliminates the difficulty of the raw material entering the inside of the fluidized sand layer in the gasification furnace, and the raw material can be suitably supplied to the inside of the fluidized sand layer in the gasification furnace.

[0065] The carrier gas is not particularly limited as long as it does not adversely affect the raw material and the fuel gas generating apparatus of the present disclosure, and examples thereof include carbon dioxide and nitrogen. When the carrier gas is a gas containing oxygen (e.g., air), combustible components (e.g., hydrogen, etc.) contained in the generated pyrolysis gas and fuel gas are burned, and the amount of the combustible components generated is reduced. In addition, the combustible components are components that are useful as fuel gas. Therefore, it is preferable that the carrier gas is, for example, a gas with a low oxygen content.

[0066] The combustion gas generation apparatus of the present disclosure may include a fuel gas supply pipe that supplies a portion of the fuel gas to the carrier gas supply unit as at least a portion of the carrier gas. In this case, the carrier gas supply unit is connected to the fuel gas supply pipe and supplies a portion of the fuel gas to the gasifier as at least a portion of the carrier gas. With this configuration, the amount of carrier gas supplied from the outside is reduced, and as a result, the energy required for fuel gas generation can be reduced.

[0067] The combustion gas generating device of the present disclosure is configured to generate CO from the combustion exhaust gas discharged from the combustion furnace. 2 Separating CO 2 A separation unit, and the CO 2 CO separated in the separation section 2is supplied to the carrier gas supply unit as at least a part of the carrier gas; 2 In this case, the carrier gas supply unit may include the above-mentioned CO 2 The CO 2 CO separated in the separation section 2 is supplied to the gasification furnace as at least a part of the carrier gas. With this configuration, the amount of carrier gas supplied from the outside is reduced, and as a result, the energy required for fuel gas generation can be reduced. 2 The separation section separates the CO 2 As long as the separator has a function of separating the above, it is not particularly limited, and examples thereof include a PSA type separator.

[0068] The combustion gas generating apparatus of the present disclosure may include a moisture content adjusting unit that adjusts the moisture content of the raw material supplied to the fluidized sand layer in the gasification furnace. The moisture content adjusting unit is not particularly limited as long as it has a function of adjusting the moisture content of the raw material supplied, and may be, for example, a mechanism (part) consisting of a dehydrator, a dryer, and a dryer bypass disclosed in JP 2020-128325 A.

[0069] The combustion gas generating apparatus of the present disclosure may include an oxygen concentration adjusting unit that adjusts the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace. According to the oxygen concentration adjusting unit, when the gas dispersion nozzle is clogged by char during fuel gas generation using the combustion gas generating apparatus of the present disclosure, the char can be burned by increasing the oxygen concentration of the fluidizing gas supplied to the gasification furnace. As a result, it is possible to resolve the interruption of fuel gas generation caused by the clogging of the gas dispersion nozzle and resume the generation of fuel gas. The oxygen concentration adjusting unit is not particularly limited as long as it can adjust the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace, and examples of the oxygen concentration adjusting unit include a mechanism that switches the fluidizing gas supplied to the gasification furnace from a gas containing water vapor, such as a mixed gas of water vapor and nitrogen, to an oxygen-containing gas (e.g., air) containing oxygen. Examples of the mechanism include a mechanism that uses a valve that adjusts the amount of mixed gas discharged from a tank (A) that stores mixed gas and the amount of oxygen-containing gas discharged from a tank (B) that stores oxygen-containing gas. After the blockage of the gas dispersion nozzle is cleared by the combustion of the char, the oxygen concentration of the fluidizing gas may be reduced by, for example, switching the fluidizing gas supplied to the gasification furnace to a mixed gas of steam and nitrogen. This allows the generation of fuel gas to be resumed. The oxygen concentration adjustment unit may be a mechanism for supplying a gas containing oxygen to the gasification furnace, more specifically, a mechanism for stopping the supply of a gas containing steam to the gasification furnace and then supplying a gas containing oxygen to the gasification furnace. The combustion gas generation device of the present invention may also include a mechanism for supplying a gas containing oxygen to the gasification furnace other than the oxygen concentration adjustment unit, instead of the oxygen concentration adjustment unit.

[0070] When the combustion gas generation device of the present disclosure includes the oxygen concentration adjusting unit, it is preferable that the combustion gas generation device includes a device for determining when to perform the operation for adjusting (increasing or returning) the oxygen concentration. Examples of the device for determining when to perform the operation for adjusting the oxygen concentration include a mechanism for measuring the pressure difference between the bottom and top of the gasification furnace and the reformer by installing a pressure sensor in each of the gasification furnace and the reformer, and a gas analyzer for measuring the concentration of carbon dioxide in the fuel gas discharged from the reformer.

[0071] [Fuel gas generating device according to another embodiment] A fuel gas generation apparatus according to another embodiment of the present disclosure (hereinafter referred to as "another fuel gas generation apparatus of the present disclosure") may be a fuel gas generation apparatus including a gasification furnace that pyrolyzes a raw material, a reforming furnace that reforms the pyrolysis gas produced in the gasification furnace to generate fuel gas, and a combustion furnace that combusts the pyrolysis residue transferred from the gasification furnace, wherein the reforming furnace is installed above the gasification furnace, and a gas dispersion nozzle for transferring the pyrolysis gas to the reforming furnace is provided between the reforming furnace and the gasification furnace, and the gasification furnace has a fluidized sand layer therein and a raw material supply port for supplying the raw material from above the fluidized sand layer, and an oxygen concentration adjustment unit that adjusts the oxygen concentration contained in the fluidized gas supplied to the gasification furnace.

[0072] In other words, the fuel gas generation apparatus according to another embodiment of the present disclosure is a fuel gas generation apparatus in which (a) the gasification furnace is provided with a raw material supply port (hereinafter also referred to as "another raw material supply port") that supplies the raw material from above the fluidized sand bed, instead of a raw material supply port that supplies the raw material into the inside of the fluidized sand bed, and (b) an oxygen concentration adjustment unit that adjusts the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace is essentially provided. With regard to each member constituting the other fuel gas generation apparatus of the present disclosure, the above descriptions regarding each member constituting the fuel gas generation apparatus of the present disclosure are cited, except for the description regarding the position of the raw material supply port constituting the fuel gas generation apparatus of the present disclosure.

[0073] Specifically, the structure of the gasifier in another fuel gas generation apparatus of the present disclosure may include, for example, the structure shown in gasifier 1-b (lower furnace) shown in Fig. 3. Providing another raw material supply port for supplying the raw material from above the fluidized sand layer means that, as shown in Fig. 3, another raw material supply port 1-d is provided on the side of gasifier 1-b at a location where there is no fluidized sand layer 1-e filled inside gasifier 1-b and where the raw material supply port 1-d is higher than the top of the fluidized sand layer (for example, a location not in contact with the fluidized sand layer filled inside the gasifier and above the position in contact with the top of the fluidized sand layer) where the fluidized sand layer is not present on the side of gasifier 1-b.

[0074] Another combustion gas generating apparatus of the present disclosure includes an oxygen concentration adjusting unit that adjusts the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace. When the gas dispersion nozzle is clogged by char when fuel gas is generated using another combustion gas generating apparatus of the present disclosure, the oxygen concentration adjusting unit can increase the oxygen concentration of the fluidizing gas supplied to the gasification furnace, thereby burning the char. As a result, it is possible to resolve the interruption of fuel gas generation caused by the clogging of the gas dispersion nozzle and resume the generation of fuel gas. The oxygen concentration adjusting unit can be the same as the oxygen concentration adjusting unit in the combustion gas generating apparatus of the present disclosure. As in the combustion gas generating apparatus of the present disclosure, after the clogging of the gas dispersion nozzle is resolved by the combustion of char, the oxygen concentration of the fluidizing gas can be reduced by switching the fluidizing gas supplied to the gasification furnace to, for example, a mixed gas of steam and nitrogen. This allows the generation of fuel gas to be resumed.

[0075] [Embodiment B: Fuel gas generation method] A fuel gas generation method according to one embodiment of the present disclosure (hereinafter referred to as the "fuel gas generation method of the present disclosure") is a fuel gas generation method carried out using the fuel gas generation apparatus of the present disclosure, and includes a raw material supplying process of supplying the raw material into the fluidized sand bed through the raw material supply port, a pyrolysis gas generation process of causing pyrolysis of the raw material inside the fluidized sand bed to proceed, and a reforming process of supplying the pyrolysis gas obtained in the pyrolysis gas generation process to the reforming furnace and reforming the pyrolysis gas to generate fuel gas.

[0076] The matters relating to the fuel gas generation method using the fuel gas generation apparatus of the present disclosure, described above in the section "Embodiment A: Fuel Gas Generation Apparatus", are incorporated by reference in the fuel gas generation method of the present disclosure. In addition, the descriptions in the section "Embodiment A: Fuel Gas Generation Apparatus" above are incorporated by reference for configurations common to the configurations of the fuel gas generation method of the present disclosure and the fuel gas generation apparatus of the present disclosure.

[0077] <Raw material supply process> The raw material supply step is a step of supplying the raw material to the inside of the fluidized sand bed through the raw material supply port. As described above, in the raw material supply step, the raw material is supplied to the inside of the fluidized sand bed, and the pyrolysis reaction of the raw material proceeds inside the fluidized sand bed. Therefore, the generated char is taken into the fluidized sand bed without scattering upward, and is discharged to the combustion furnace. Therefore, the fuel gas generation method of the present disclosure can reduce the above-mentioned upward scattering of char. In addition, by including the raw material supply step, the fuel gas generation method of the present disclosure can supply the raw material to the gasification furnace even if it does not include a carrier gas supply step described later, or if it includes the carrier gas supply step but the flow rate (amount) of the carrier gas supplied is smaller than that of the conventional fuel gas generation method. Therefore, it is also possible to reduce the upward scattering of char caused by the supply of a large amount of carrier gas to the gasification furnace. From the above, the fuel gas generation method of the present disclosure has an effect of reducing the possibility that normal operation is hindered due to clogging of the gas dispersion nozzle.

[0078] The fuel gas generation method of the present disclosure preferably further includes a carrier gas supplying step of supplying a carrier gas to the raw material supplied to the inside of the fluidized sand bed using the carrier gas supplying unit among the fuel gas generation devices of the present disclosure in addition to the raw material supplying step. In this case, the raw material can be suitably supplied to the inside of the fluidized sand bed of the gasification furnace. In addition, the flow rate of the carrier gas in the carrier gas supplying step is preferably 1.5 m / s or more, more preferably 2.0 m / s or more, and most preferably 2.5 m / s or more. By having the flow rate of the carrier gas be 1.5 m / s or more, the raw material can be more suitably supplied to the inside of the fluidized sand bed of the gasification furnace. The flow rate of the carrier gas in the carrier gas supplying step is preferably 5.0 m / s or less, more preferably 4.5 m / s or less, and most preferably 4.0 m / s or less. By setting the flow velocity of the carrier gas to 5.0 m / s or less, it is possible to more suitably reduce the upward scattering of char caused by the supply of a large amount of carrier gas to the gasification furnace.

[0079] The moisture content, particle size, bulk density, and other shapes of the raw material supplied in the raw material supplying step can be adjusted before the raw material supplying step. For example, a method of controlling the moisture content of the raw material can be a method of using the fuel gas generating apparatus of the present disclosure that includes the moisture content adjusting unit to appropriately adjust the moisture content of the raw material supplied to the inside of the fluidized sand layer by the moisture content adjusting unit. In addition, a method of adjusting the particle size, bulk density, and other shapes of the raw material can be a method of sieving the raw material before supplying it.

[0080] The moisture content of the raw material is preferably 0% by weight or more and 40% by weight or less, and more preferably 10% by weight or more and 30% by weight or less, when the weight of the entire raw material is taken as 100% by weight. The particle size of the raw material is preferably 0.5 mm or more and 10 mm or less, and particularly preferably 1 mm or more and 4 mm or less. The bulk density of the raw material is 300 kg / m3 More than 700kg / m 3 It is preferable that the thickness is less than 400 kg / m 3 More than 600kg / m 3 It is more preferable that the moisture content, particle size and bulk density of the raw material are within the above-mentioned preferred ranges, the handleability of the raw material is improved, and the raw material can be more suitably supplied to the inside of the fluidized sand layer in the gasification furnace. In addition, among the above-mentioned characteristics of the raw material, the moisture content has a large effect on the production amount and composition of the fuel gas generated by the fuel gas generation method of the present disclosure. Here, by controlling the moisture content of the raw material within the above-mentioned preferred ranges, the production amount of the fuel gas is suitably increased, and the proportion of the components that function as fuel (e.g., hydrogen) in the entire fuel gas is increased, and as a result, a fuel gas with excellent function as a fuel gas can be generated. In addition, the fuel gas generation method of the present disclosure supplies the raw material to the inside of the fluidized sand layer. Therefore, even if the difference between the bulk density of the raw material and the bulk density of the fluidized medium is large, the raw material can be kept inside the fluidized sand layer, and as a result, the pyrolysis gas can be suitably generated.

[0081] <Pyrolysis gas generation process> The pyrolysis gas generation step is a step of obtaining pyrolysis gas by advancing pyrolysis of the raw material inside the fluidized sand bed. The reaction conditions in the pyrolysis gas generation step are not particularly limited as long as the raw material can be pyrolyzed to obtain pyrolysis gas. The reaction conditions in the pyrolysis gas generation step can be, for example, heating the raw material in the presence of steam at 600°C to 900°C, more preferably 700°C to 850°C, while retaining the raw material in the gasification furnace (more specifically, inside the fluidized sand bed in the gasification furnace) for 0.1 to 1 hour, more preferably 0.2 to 0.4 hours. The above temperature means the temperature inside the gasification furnace, particularly inside the fluidized sand bed in the gasification furnace. In addition, the amount of fluidizing gas supplied to the gasification furnace in the pyrolysis gas generation process is not particularly limited as long as it can fluidize the fluidized sand in the gasification furnace and pyrolyze the raw material, and can be, for example, nitrogen gas: 9.9 L / min, water vapor: 4.0 g / min, and nitrogen gas supplied as a carrier for water vapor: 1.0 L / min.

[0082] <Modification process> The reforming step is a step of supplying the pyrolysis gas obtained in the pyrolysis gas generation step to the reforming furnace and reforming the pyrolysis gas to generate a fuel gas. The reaction conditions in the reforming step are not particularly limited as long as the pyrolysis gas can be reformed to generate a fuel gas. The reaction conditions in the reforming step can be, for example, heating the pyrolysis gas in the presence of steam at 800°C to 1000°C, more preferably 850°C to 900°C, while retaining the pyrolysis gas in the reforming furnace (more specifically, inside the fluidized sand layer in the reforming furnace) for 0.5s to 3s, more preferably 1s to 2.5s. The above temperature means the temperature inside the reforming furnace, particularly the temperature inside the fluidized sand layer in the reforming furnace. In addition, in the reforming step, it is preferable to use only the pyrolysis gas supplied from the gasification furnace as the fluidizing gas without supplying the other fluidizing gas. In that case, the amount of fluidizing gas supplied from the outside can be reduced, and the energy required for fuel gas generation can be suitably reduced.

[0083] <Combustion in a Combustion Furnace> In the fuel gas generation method of the present disclosure, the char generated in the pyrolysis gas generation step and the dried sludge optionally supplied as auxiliary fuel are supplied to the combustion furnace and combusted in the combustion furnace. The conditions for burning the char in the combustion furnace are not particularly limited as long as the char can be burned. The conditions for burning the char can be, for example, heating the char and the dried sludge optionally supplied as auxiliary fuel at 800°C to 1100°C, more preferably 850°C to 1000°C, and even more preferably 900°C to 950°C while retaining them in the combustion furnace (more specifically, inside the fluidized sand layer in the combustion furnace) for 1 second to 15 minutes, more preferably 3 seconds to 10 minutes. The fluidizing gas supplied to the combustion furnace can be, for example, air, and the supply amount is not particularly limited as long as the fluidizing sand in the combustion furnace can be fluidized and the char can be burned to generate a combustion exhaust gas.

[0084] The auxiliary fuel may be a biomass raw material such as woody biomass other than dried sludge.

[0085] <Oxygen concentration adjustment process> The fuel gas generation method of the present disclosure may include an oxygen concentration adjustment step of adjusting the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace by using the fuel gas generation device of the present disclosure that includes the oxygen concentration adjustment unit. As described above, when the gas dispersion nozzle is clogged by char and the pyrolysis gas generation step is interrupted, the oxygen concentration adjustment step is performed to increase the oxygen concentration of the fluidizing gas supplied to the gasification furnace, thereby burning the char and eliminating the blockage. Then, the oxygen concentration of the fluidizing gas supplied to the gasification furnace is reduced and returned to the original concentration, thereby restarting the pyrolysis gas generation step. In addition, in the oxygen concentration adjustment step, it is preferable to increase the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace when the value of the differential pressure of the reformer / differential pressure of the gasification furnace exceeds a predetermined reference value. Here, the differential pressure of the reformer means the pressure difference between the bottom and top of the reformer, and the differential pressure of the gasification furnace means the pressure difference between the bottom and top of the gasification furnace. The case where the value of the differential pressure in the reformer / the differential pressure in the gasifier exceeds a predetermined reference value indicates a case where the gas dispersion nozzle is clogged by char and the pyrolysis gas generation process cannot be performed. Therefore, in this case, by increasing the oxygen concentration contained in the fluidizing gas supplied to the gasifier, the interruption of the fuel gas generation caused by the clog of the gas dispersion nozzle can be preferably eliminated. In addition, by not increasing the oxygen concentration contained in the fluidizing gas supplied to the gasifier until the gas dispersion nozzle is clogged, a decrease in the amount of fuel gas generated by the combustion of the pyrolysis gas can be avoided. The oxygen concentration adjustment process may be a cleaning process in which, when the value of the differential pressure in the reformer / the differential pressure in the gasifier exceeds a predetermined reference value, the supply of the raw material to the gasifier and the supply of a gas containing water vapor for pyrolyzing the raw material are stopped to stop the pyrolysis gas generation process, and subsequently, a gas containing oxygen is supplied to the gasifier to reduce the value of the differential pressure in the reformer / the differential pressure in the gasifier.Furthermore, when the fuel gas generation method of the present disclosure is carried out using a fuel gas generation apparatus of the present disclosure that does not include the oxygen concentration adjustment unit and that includes a mechanism for supplying oxygen-containing gas to the gasification furnace other than the oxygen concentration adjustment unit, in the fuel gas generation method of the present disclosure, instead of the oxygen concentration adjustment process, when the value of the differential pressure in the reformer furnace / differential pressure in the gasification furnace exceeds a predetermined standard value, the supply of the raw material to the gasification furnace and the supply of gas containing water vapor for pyrolyzing the raw material are stopped to stop the pyrolysis gas generation process, and then a cleaning process may be carried out in which an oxygen-containing gas is supplied to the gasification furnace using a mechanism for supplying oxygen-containing gas to the gasification furnace to lower the value of the differential pressure in the reformer furnace / differential pressure in the gasification furnace. That is, the fuel gas generating method of the present disclosure may further include a cleaning step in which, when the value of the differential pressure in the reformer / the differential pressure in the gasifier exceeds a predetermined reference value, the supply of the raw material to the gasifier and the supply of the gas containing water vapor for pyrolyzing the raw material are stopped to stop the pyrolysis gas generating step, and then, a mechanism for supplying a gas containing oxygen to the gasifier is used to supply a gas containing oxygen to the gasifier to reduce the value of the differential pressure in the reformer / the differential pressure in the gasifier. By carrying out the cleaning step, it is possible to preferably eliminate the interruption of the generation of the fuel gas due to the clogging of the gas dispersion nozzle, as in the case of carrying out the oxygen concentration adjustment step. In the fuel gas generating method of the present disclosure, the predetermined reference value can be set appropriately, and a preferable predetermined reference value may be, for example, 0.6.

[0086] <Gas supply to upper LS and lower LS> In the fuel gas generation method of the present disclosure, gas is supplied to the inside of the lower LS and the inside of the upper LS. This can reduce the possibility of backflow of the fluidized sand circulating in the device. As a result, when the fuel gas generation method of the present disclosure is carried out, the fluidized sand can be suitably circulated inside the fuel gas generation device of the present disclosure. In addition, by supplying gas to the inside of the LS, the generated fuel gas and the combustion exhaust gas can be suitably separated and recovered.

[0087] [Fuel gas generating method according to another embodiment] A fuel gas generation method according to another embodiment of the present disclosure (hereinafter referred to as "another fuel gas generation method of the present disclosure") may be a fuel gas generation method carried out using another fuel gas generation apparatus of the present disclosure, and may include a raw material supplying step of supplying the raw material above the fluidized sand bed via the raw material supply port, a pyrolysis gas generation step of proceeding with pyrolysis of the raw material in the fluidized sand bed to obtain a pyrolysis gas, a reforming step of supplying the pyrolysis gas obtained in the pyrolysis gas generation step to the reforming furnace and reforming the pyrolysis gas to generate a fuel gas, and an oxygen concentration adjustment step of adjusting the oxygen concentration contained in the fluidized gas supplied to the gasification furnace using the oxygen concentration adjustment unit.

[0088] In other words, a fuel gas generation method according to another embodiment of the present disclosure is a fuel gas generation method in which (a) instead of the fuel gas generation apparatus of the present disclosure, another fuel gas generation apparatus of the present disclosure is used; (b) instead of the raw material supply step of supplying the raw material into the inside of the fluidized sand bed through the raw material supply port, a raw material supply step (hereinafter also referred to as "another raw material supply step") is performed in which the raw material is supplied from above the fluidized sand bed through the another raw material supply port; (c) instead of the pyrolysis gas generation step of causing pyrolysis of the raw material to proceed inside the fluidized sand bed to obtain pyrolysis gas, a pyrolysis gas generation step (hereinafter also referred to as "another pyrolysis gas generation step") is performed in which the raw material in the pyrolysis gas generation step is caused to proceed in the fluidized sand bed to obtain pyrolysis gas; and (d) the oxygen concentration adjustment step is performed as an essential step. With respect to each step constituting the fuel gas generation method of the present disclosure, the above description of each step constituting the fuel gas generation method of the present disclosure, other than the step of supplying the raw material and the step of pyrolyzing the raw material, is cited. In the separate pyrolysis gas generation step, the raw material supplied in the separate raw material supply step is pyrolyzed, for example, on the surface and inside of a fluidized sand layer in a gasification furnace to obtain a pyrolysis gas.

[0089] Another combustion gas generation method of the present disclosure may include an oxygen concentration adjustment step of adjusting the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace by the oxygen concentration adjustment unit using another fuel gas generation device of the present disclosure. As described above, when the gas dispersion nozzle is clogged by char and the pyrolysis gas generation step is interrupted, the oxygen concentration adjustment step is performed to increase the oxygen concentration of the fluidizing gas supplied to the gasification furnace, thereby burning the char and eliminating the blockage. Then, the oxygen concentration of the fluidizing gas supplied to the gasification furnace is reduced and returned to the original concentration, thereby restarting the pyrolysis gas generation step. In addition, in the oxygen concentration adjustment step, it is preferable to increase the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace when the value of the differential pressure of the reformer furnace / the differential pressure of the gasification furnace exceeds a predetermined reference value. The case where the value of the differential pressure of the reformer furnace / the differential pressure of the gasification furnace exceeds a predetermined reference value refers to the case where the gas dispersion nozzle is clogged by char and the pyrolysis gas generation step cannot be performed. Therefore, in this case, by increasing the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace, the interruption of fuel gas generation due to the blockage of the gas dispersion nozzle can be preferably eliminated. Also, by not increasing the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace until the gas dispersion nozzle is blocked, a decrease in the amount of fuel gas generated due to the combustion of pyrolysis gas can be avoided. Note that, in another fuel gas generation method disclosed herein, the oxygen concentration adjustment step may also be a cleaning step in which, when the differential pressure of the reformer / differential pressure in the gasification furnace exceeds a predetermined reference value, the supply of the raw material to the gasification furnace and the supply of a gas containing water vapor for pyrolyzing the raw material are stopped to stop the pyrolysis gas generation step, and then a gas containing oxygen is supplied to the gasification furnace to reduce the differential pressure of the reformer / differential pressure in the gasification furnace.Furthermore, when another fuel gas generation method of the present disclosure is carried out using another fuel gas generation apparatus of the present disclosure that does not have the oxygen concentration adjustment unit and that has a mechanism for supplying oxygen-containing gas to the gasification furnace other than the oxygen concentration adjustment unit, in the other fuel gas generation method of the present disclosure, instead of the oxygen concentration adjustment process, when the value of the differential pressure in the reformer furnace / differential pressure in the gasification furnace exceeds a predetermined standard value, the supply of the raw material to the gasification furnace and the supply of gas containing water vapor for pyrolyzing the raw material are stopped to stop the pyrolysis gas generation process, and then a cleaning process may be carried out in which an oxygen-containing gas is supplied to the gasification furnace using a mechanism for supplying oxygen-containing gas to the gasification furnace to lower the value of the differential pressure in the reformer furnace / differential pressure in the gasification furnace. That is, the fuel gas generating method of the present disclosure may further include a cleaning step in which, when the value of the pressure difference in the reformer / pressure difference in the gasifier exceeds a predetermined reference value, the supply of the raw material to the gasifier and the supply of a gas containing water vapor for pyrolyzing the raw material are stopped to stop the pyrolysis gas generating step, and then, a mechanism for supplying a gas containing oxygen to the gasifier is used to supply a gas containing oxygen to the gasifier to reduce the value of the pressure difference in the reformer / pressure difference in the gasifier. By carrying out the cleaning step, it is possible to preferably eliminate the interruption of the generation of the fuel gas due to the clogging of the gas dispersion nozzle, as in the case of carrying out the oxygen concentration adjustment step. In the fuel gas generating method of the present disclosure, the predetermined reference value can be set appropriately, and a preferable predetermined reference value may be, for example, 0.6.

[0090] [Example] <Embodiment 1> As examples of the fuel gas generation method of the present disclosure, fuel gas generation methods according to Embodiment 1-1 of the present disclosure, Embodiment 1-2 of the present disclosure, and Embodiment 1-3 of the present disclosure will be described with reference to Figs. 10 to 12.

[0091] The fuel gas generating apparatuses of the present disclosure used in the fuel gas generating methods according to embodiment 1-1, embodiment 1-2, and embodiment 1-3 of the present disclosure have a common structure. Specifically, the fuel gas generating apparatuses include an apparatus generally called a "triple-tower circulating fluidized bed apparatus" and in particular have the following features (a1) to (d1).

[0092] (a1) A reformer 1-a equipped with a gas distribution plate is installed on top of a gasifier 1-b that constitutes a three-tower circulating fluidized bed apparatus 1. The gasifier 1-b and the reformer 1-a are connected by a gas distribution plate equipped with a standpipe, and the gasifier 1-b is equipped with a raw material insertion pipe for supplying raw material.

[0093] (b1) The raw material insertion pipe is installed at a position 150 to 350 mm (30 to 70%) into the sand layer from the top surface of the fluidized sand layer of the gasifier 1-b, at an angle of 30 to 60° to the horizontal. The length of the fluidized sand layer in the gasifier in the height direction is 500 mm (100%).

[0094] (c1) The raw material insertion tube is equipped with a nozzle for supplying a carrier gas, and the carrier gas can be supplied at a flow rate of 1.5 to 5 m / s. This reduces the possibility that the raw material will flow back from the gasification furnace 1-b to the raw material insertion tube due to the internal pressure of the gasification furnace 1-b, and that the raw material will accumulate in the raw material insertion tube.

[0095] (d1) The system includes a drying device 2 connected to the gasification furnace 1-b for drying the raw material to be supplied, a combustion exhaust gas recovery device 4 connected to the combustion furnace 1-c for recovering the heat of the combustion exhaust gas, a fuel gas recovery device 5 connected to the reformer 1-a for recovering the heat of the fuel gas, and a gas refining equipment (for producing purified hydrogen) 3 for refining the fuel gas connected to the fuel gas recovery device 5, or a gas refining equipment (for gas engine power generation) 25 and a gas engine generator 6 connected to the gas refining equipment (for gas engine power generation) 25. The gas refining equipment (for producing purified hydrogen) 3 is composed of a scrubber cooling device, a CO shift reactor, an activated carbon adsorption tower, a PSA type separation device, etc., and is a facility for increasing the hydrogen concentration of the fuel gas by refining. The gas refining equipment (for gas engine power generation) 25 is composed of a scrubber cooling device, an activated carbon adsorption tower, etc., and is a facility for purifying the fuel gas by cleaning it.

[0096] (Embodiment 1-1) Fig. 10 is a schematic diagram showing the configuration of a fuel gas generation method according to embodiment 1-1 of the present disclosure. As shown in Fig. 10, the fuel gas generation method according to embodiment 1-1 of the present disclosure is a method including the following steps (1) to (4).

[0097] (1) The dewatered sludge 9 as the raw material is fed into the dryer 2 together with the dryer air carrier 10 and dried to obtain dried sludge. A part of the exhaust gas obtained at this time is discharged through the dryer exhaust gas drain 19, while another part of the exhaust gas, the dryer exhaust gas 20, is supplied to the combustion furnace 1-c as part of the air 7 for the combustion furnace.

[0098] (2) A part of the dried sludge obtained in step (1) is supplied as dried sludge (for fuel gas production) 13 to the gasification furnace 1-b as a raw material, and the raw material supplying step, the pyrolysis gas production step, and the reforming step are carried out to produce fuel gas from the reformer 1-a. Another part of the dried sludge is supplied as dried sludge (for auxiliary fuel) 11 to the combustion furnace 1-c as auxiliary fuel. When the pyrolysis gas production step is carried out, gasification steam 8 is supplied to the gasification furnace 1-b as a fluidizing gas. At that time, combustion exhaust gas 15 is discharged from the combustion furnace 1-c. The fuel gas is H 2 , CO, CO 2 , C.H. 4 The main ingredients are:

[0099] (3) The fuel gas generated in step (2) is introduced into a gas purification facility (for producing purified hydrogen) 3 and purified to produce purified hydrogen 14 and CH 4 , CO 2 and a fuel gas refinery off-gas 12 containing the above-mentioned components, and the purified hydrogen 14 and the fuel gas refinery off-gas 12 are separated.

[0100] (4) A portion of the fuel gas refinery off-gas 12 obtained in step (3) is supplied to the combustion furnace 1-c and used as a heat source, and another portion of the fuel gas refinery off-gas 12 is supplied to the gasification furnace 1-b and used as a carrier gas for supplying raw sludge.

[0101] (Embodiment 1-2) Fig. 11 is a schematic diagram showing the configuration of a fuel gas generation method according to embodiment 1-2 of the present disclosure. As shown in Fig. 11, the fuel gas generation method according to embodiment 1-2 of the present disclosure is a method including the following steps (1') to (3').

[0102] (1') The same steps as steps (1) and (2) in the fuel gas production method according to embodiment 1-1 of the present disclosure are carried out.

[0103] (2') The fuel gas generated in step (1') is introduced into a gas purification facility (for gas engine power generation) 25, where it is cleaned and purified. After that, a portion of the purified fuel gas is supplied to a gas engine generator 6 to generate electricity, obtaining electricity 18. In addition, another portion of the purified fuel gas is further split into two. Note that the gas engine combustion exhaust gas 16 discharged from the gas engine generator 6 is discharged to the outside together with the combustion exhaust gas 15.

[0104] (3') One of the fuel gases split in step (2') is supplied to the combustion furnace 1-c as fuel gas (combustion furnace auxiliary fuel) 17 and used as a heat source, and the other of the fuel gases is supplied to the gasification furnace 1-b and used as a carrier gas for supplying the raw sludge.

[0105] (Embodiments 1-3) Fig. 12 is a schematic diagram showing the configuration of a fuel gas generation method according to embodiment 1-3 of the present disclosure. As shown in Fig. 12, the fuel gas generation method according to embodiment 1-3 of the present disclosure is a method including the following steps (1'') to (3'').

[0106] (1″) The same steps as steps (1′) to (3′) in the fuel gas production method according to embodiment 1-2 of the present disclosure are carried out.

[0107] (2'') Step (1''), specifically, the combustion exhaust gas 15 generated in the same step as step (2) in the fuel gas generation method according to embodiment 1-1 of the present disclosure, is introduced into a gas separator such as a PSA type separation device to separate CO from the combustion exhaust gas 15. 2 and separate the off-gas 24 and high-concentration CO 2 Gas (for raw sludge carrier) 23 is obtained.

[0108] (3´´) High-concentration CO obtained in step (2´´) 2 Gas (for raw sludge carrier) 23 is supplied to the gasification furnace 1-b and used as a carrier gas for supplying raw sludge.

[0109] In the fuel gas generation method, when a gas containing oxygen such as air is used as a carrier gas supplied to the gasification furnace, H contained in the pyrolysis gas generated in the gasification furnace and the fuel gas generated from the pyrolysis gas in the reformer is 2 , CO, C.H. 4 The calorific value of the fuel gas produced is reduced because components such as nitrogen (N 2 gas) and carbon dioxide (CO 2 When a carrier gas that does not combust the components, such as ethanol, is supplied from the outside and used, supply costs and generation energy are required, and the energy required for fuel gas generation increases. On the other hand, the fuel gas generation methods according to embodiments 1-1 to 1-3 of the present disclosure commonly use a carrier gas that does not combust the components, and reduce the amount of the carrier gas supplied from the outside. Therefore, the fuel gas generation methods according to embodiments 1-1 to 1-3 of the present disclosure have the effect of reducing the possibility of a decrease in the calorific value of the fuel gas and generating fuel gas without the supply of additional energy by producing a carrier gas from the outside.

[0110] <Embodiment 2> As an example of the fuel gas generation method of the present disclosure, a fuel gas generation method according to a second embodiment of the present disclosure will be described with reference to FIG.

[0111] 13 is a schematic diagram showing the configuration of a fuel gas generation method according to embodiment 2 of the present disclosure. The fuel gas generation apparatus of the present disclosure used in the fuel gas generation method according to embodiment 2 of the present disclosure is a fuel gas generation apparatus including an apparatus generally called a "triple-tower circulating fluidized bed apparatus", and in particular has the following characteristics (a2) to (d2).

[0112] (a2) Having the same characteristics as (a1) to (c1) above.

[0113] (b2) A pressure sensor is installed in each of the gasifier 1-b and the reformer 1-a. Specifically, a differential pressure gauge 27 is installed in the gasifier 1-b, and a differential pressure gauge 28 is installed in the reformer 1-a. The pressure generated by the differential pressure gauge 27 is the pressure difference (differential pressure) between the bottom and top of the gasifier 1-b, and its value is taken as "P1." The pressure generated by the differential pressure gauge 28 is the pressure difference (differential pressure) between the bottom and top of the reformer 1-a, and its value is taken as "P2." In the following, the differential pressure of the reformer is also referred to as the "reformer differential pressure."

[0114] (c2) An air supply valve (gasification furnace) 21 for supplying air to the gasification furnace 1-b, an air supply valve (raw material insertion pipe) 22 for supplying air to the raw material insertion pipe, a steam supply valve 29 for adjusting the amount of steam for gasification 8 supplied to the gasification furnace 1-b, and a CO 2 Gas analyzer for measuring the concentration of CO 2 The gasification furnace 1-c is equipped with an oxygen concentration control unit 30 that controls the amount of carrier gas supplied to the raw material insertion tube, and a carrier gas supply valve 31 that controls the amount of carrier gas supplied to the raw material insertion tube. In FIG. 13, the air supply valve (gasification furnace) 21 and the steam supply valve 29 correspond to the oxygen concentration adjustment unit 32. Both the air supply valve (gasification furnace) 21 and the air supply valve (raw material insertion tube) 22 are connected to a device that supplies combustion furnace air 7 to the combustion furnace 1-c. Therefore, by using the air supply valve (gasification furnace) 21 and the air supply valve (raw material insertion tube) 22, a portion of the combustion furnace air 7 can be supplied to the gasification furnace 1-b and the raw material insertion tube.

[0115] (d2) The fuel gas generating apparatus used in the fuel gas generating methods according to the embodiments 1-1 to 1-3 of the present disclosure includes a mechanism that prepares the raw material to be introduced into the gasifier 1-b.

[0116] As shown in FIG. 13, the fuel gas production method according to the second embodiment of the present disclosure is a method including the following steps (1''') to (4''').

[0117] (1″″) The same steps as steps (1) and (2) in the fuel gas production method according to embodiment 1-1 are carried out.

[0118] (2´´´) While carrying out step (1´´´), the value of the differential pressure "P2" of the reformer 1-a / the differential pressure "P1" of the gasifier 1-b is measured, and if the value exceeds 0.6, the following operations (i) to (iii) are carried out.

[0119] (i) The raw sludge supply is stopped.

[0120] (ii) The fluidizing gas to the gasification furnace is switched from steam to air by closing the steam supply valve 29 and the carrier gas supply valve 31 and opening the air supply valve (gasification furnace) 21 and the air supply valve (raw material insertion pipe) 22. As a result, the char adhering to the gas dispersion nozzle is combusted, and the differential pressure in the reformer (reformer differential pressure) is reduced.

[0121] (iii) Gas analyzer (CO 2 Using the concentration measurement 30, CO generated by char combustion was measured. 2 While measuring the concentration, 2 The concentration of CO from char combustion decreases. 2 It is confirmed that discharge has ended. At the same time, it is confirmed that the value of "P2" / "P1" is 0.6 or less. When both are confirmed, the supply of raw sludge is resumed, the steam supply valve 29 and the carrier gas supply valve 31 are opened, and the air supply valve (gasification furnace) 21 and the air supply valve (raw material insertion pipe) 22 are closed, thereby changing the gas supplied to the gasification furnace back to steam. As a result, the generation of fuel gas is resumed.

[0122] The fuel gas generation method according to the first to third embodiments of the present disclosure has an advantage that the interruption of fuel gas generation caused by the clogging of the gas dispersion nozzle can be preferably eliminated, and the oxygen concentration in the fluidizing gas supplied to the gasifier is not increased until the gas dispersion nozzle is clogged, thereby preventing a decrease in the amount of fuel gas generated by the combustion of pyrolysis gas.

[0123] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure.

[0124] The present disclosure includes the following inventions [1] to

[13] . [1] A gasification furnace for pyrolyzing the raw material; a reformer for reforming the pyrolysis gas produced in the gasification furnace to generate a fuel gas; A fuel gas generating apparatus comprising: a combustion furnace that combusts the pyrolysis residue transferred from the gasification furnace, The reformer is installed above the gasifier, a gas dispersion nozzle for transferring the pyrolysis gas to the reforming furnace is provided between the reforming furnace and the gasification furnace; The gasification furnace has a fluidized sand bed therein and a raw material supply port for supplying the raw material into the fluidized sand bed. [2] The fuel gas generation apparatus described in [1], wherein when the height of a char discharge port, which discharges the pyrolysis residue from the gasification furnace to the combustion furnace, from the bottom of the gasification furnace is taken as 100%, the raw material supply port is located at a position that is 30% to 70% away from the char discharge port toward the bottom of the gasification furnace. [3] A raw material insertion pipe for transporting the raw material is connected to the raw material supply port, The fuel gas generation apparatus according to [1] or [2], wherein the raw material insertion pipe is installed at an angle of 30° to 60° with respect to the horizontal direction with respect to the gasification furnace. [4] The fuel gas generation apparatus according to any one of [1] to [3], further comprising a carrier gas supplying unit that supplies a carrier gas to the raw material supplied into the fluidized sand bed. [5] The fuel gas generation apparatus according to any one of [1] to [4], wherein the fluidized sand layer contains one or more selected from the group consisting of olivine, alumina, and calcined lime. [6] The fuel gas generating apparatus according to [4], further comprising a fuel gas supply pipe that supplies a portion of the fuel gas to the carrier gas supply section as at least a portion of the carrier gas. [7] The CO contained in the fuel gas is converted to CO 2 a conversion section for converting the gas into a converted gas; From the converted gas, H 2 and CO 2 and C.H. 4 and an off-gas separation unit for separating the off-gas from the off-gas, a supply pipe for supplying a portion of the off-gas to the carrier gas supply unit as at least a portion of the carrier gas to the carrier gas supply unit; and The fuel gas generating apparatus according to [4] or [6], further comprising an off-gas supply pipe to the combustion furnace, which supplies another portion of the off-gas to the combustion furnace. [8] CO from the flue gas discharged from the combustion furnace 2 Separating CO 2 A separation section, and CO 2 CO separated in the separation section 2 is supplied to the carrier gas supply unit as at least a part of the carrier gas; 2 The fuel gas generating apparatus according to any one of [4], [6] and [7], further comprising a supply pipe. [9] The fuel gas generation apparatus according to any one of [1] to [8], further comprising an oxygen concentration adjusting unit that adjusts the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace.

[10] A fuel gas generation method carried out using the fuel gas generation apparatus according to any one of [1] to [9], A raw material supplying step of supplying the raw material into the fluidized sand bed through the raw material supply port; a pyrolysis gas generating step of causing pyrolysis of the raw material to proceed inside the fluidized sand bed to obtain a pyrolysis gas; and A fuel gas generating method comprising: a reforming step of supplying the pyrolysis gas obtained in the pyrolysis gas generating step to the reforming furnace and reforming the pyrolysis gas to generate a fuel gas.

[11] A fuel gas generation method carried out using the fuel gas generation apparatus according to any one of [4] and [6] to [8], The fuel gas generation method according to

[10] , further comprising a carrier gas supplying step of using the carrier gas supplying unit to supply a carrier gas having a flow rate of 1.5 m / s or more and 5.0 m / s or less to the raw material being supplied inside the fluidized sand bed.

[12] [9] A method for generating fuel gas, which is carried out using the fuel gas generating apparatus described in the above, an oxygen concentration adjusting step of adjusting the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace by using the oxygen concentration adjusting unit; The fuel gas generation method described in

[10] or

[11] , wherein, in the oxygen concentration adjustment process, when the value of the differential pressure of the reformer / the difference of the gasification furnace exceeds a predetermined standard value, the oxygen concentration contained in the flowing gas supplied to the gasification furnace is increased.

[13] The fuel gas generation method described in any one of

[10] to

[12] , further comprising a cleaning process in which, when the pressure difference in the reformer / pressure difference inside the gasification furnace exceeds a predetermined standard value, the supply of the raw material to the gasification furnace and the supply of gas containing water vapor for pyrolyzing the raw material are stopped to stop the pyrolysis gas generation process, and then a gas containing oxygen is supplied to the gasification furnace to reduce the pressure difference in the reformer / pressure difference inside the gasification furnace. EXAMPLES

[0125] Hereinafter, an embodiment using the fuel gas generating device and the fuel gas generating method described above will be described.

[0126] [Examples 1-1, 1-2 and Comparative Example 1] 1. Test Method (1) Test sample In Examples 1-1 and 1-2 and Comparative Example 1, olivine was used as the fluidizing medium (fluidizing sand). Specifically, it was commercially available No. 7 olivine (Toho Olivine Manufacturing Co., Ltd.), whose bulk density was 1660 kg / m 3 The average particle size was about 150 μm.

[0127] In Examples 1-1 and 1-2 and Comparative Example 1, raw material sludge prepared by the method described below was used as the raw material. Granular dried sludge with a moisture content of 20-30% by weight discharged from a sludge dryer at a sewage treatment plant was sieved and the particle size was adjusted to be within the range of 1-4 mm. Next, using a small dryer for experimental research (manufacturer: Yamato Scientific Co., Ltd., product name: F0410), the granular dried sludge after sieving was re-dried at a temperature of 105°C for one day and night to prepare raw sludge. The moisture content of the raw sludge was less than 1% by weight, and the bulk density was 570 kg / m 3 It was.

[0128] (2) Test equipment and test method <Test Equipment> In Examples 1-1 and 1-2 and Comparative Example 1, a three-tower circulating fluidized bed test apparatus (hereinafter, simply referred to as the "test apparatus") shown in FIG. 1 was used. The test apparatus was mainly composed of a gasifier, a reformer, a combustion furnace, a riser, an upper LS, a lower LS, and a cyclone. The combustion furnace had an inner diameter of φ200 mm and a height of 1000 mm, and was filled with fluidized medium up to a height of about 700 mm from the bottom. The riser had an inner diameter of φ40 mm, and the height of the top of the riser was about 6 m from the ground level. An external heater was installed in the part other than the riser. This made it possible to maintain the temperature of the part other than the riser at a predetermined temperature. A thermocouple was installed in the fluidized sand layer of each furnace, the gasifier, the reformer, and the combustion furnace. Therefore, by adjusting the heater output of the thermocouple, the temperature of the fluidized sand layer of each furnace could be adjusted to a desired temperature. In addition, a differential pressure gauge was installed in each furnace. This allows the pressure loss of each furnace fluidized sand layer (including the gas dispersion plate) to be measured. Furthermore, the gasifier and reformer are equipped with standpipes, and the circulating medium flows from the upper LS into the reformer, and if it overflows in the reformer, it falls through the standpipe into the gasifier and is discharged to the lower LS.

[0129] In the test equipment of Examples 1-1 and 1-2 and Comparative Example 1, the gasification furnace and tower diameter were an inner diameter of φ150 mm, and the stand pipe installed inside was an outer diameter of φ40 mm. In the test equipment of Examples 1-1 and 1-2 and Comparative Example 1, the gasification furnace was connected to the lower LS, and the bed material was filled up to the outlet pipe for overflowing the bed material, and the height of the outlet pipe was 500 mm.

[0130] In the test equipment of Examples 1-1 and 1-2, a raw material insertion tube with an inner diameter of φ14 mm was installed at a position 250 mm from the bottom of the gasifier and 250 mm from the top of the fluidized sand bed. The installation angle was 45° with respect to the horizontal direction. On the other hand, in the test equipment of Comparative Example 1, the raw material insertion tube was installed at a position 400 mm from the top of the fluidized sand bed of the gasifier and 100 mm from the reformer gas dispersion plate.

[0131] Specifically, the structure of the gas dispersion plate used in Examples 1-1 and 1-2 and Comparative Example 1 was as shown in Figure 4. The structures of the gasifier and reformer used in Examples 1-1 and 1-2 were as shown in Figure 2. The structures of the gasifier and reformer used in Comparative Example 1 were as shown in Figure 3.

[0132] <Test Method> In Examples 1-1 and 1-2 and Comparative Example 1, steam and N were used as fluidizing gas in the gasification furnace. 2 The mixed gas of H is supplied to the bed material to fluidize it and gasify the sewage sludge. 2 , CO, CO 2 , C.H. 4 Fuel gas, the main component of which was sewage sludge, and char were produced. Air was supplied to the combustion furnace as the fluidizing gas, and the char generated by the gasification of sewage sludge in the gasification furnace was burned, while the fluidizing medium was sprayed up into the riser section and circulated to the upper LS and reformer. Measurement seats were installed 100 mm below the reformer gas dispersion plate and at the top of the reformer (fuel gas outlet), and the differential pressure of the reformer fluidized sand layer (including the gas dispersion nozzle, etc.) was measured.

[0133] In Examples 1-1 and 1-2, N was used as the carrier gas.2 The sludge raw material was fed into the fluidized sand bed by adjusting the amount of carrier gas so that the gas flow rate in the raw material insertion tube was 2.2 to 3.8 m / s (bottom feed). More specifically, as shown in Table 1 below, the amount of carrier gas fed in Example 1-1 was 25 to 30 L / min (gas flow rate: 2.7 to 3.2 m / s), and the amount of carrier gas fed in Example 1-2 was 20 L / min (gas flow rate: 2.2 m / s).

[0134] On the other hand, in Comparative Example 1, similar to Example 1, the carrier gas was adjusted so that the gas flow velocity in the raw material insertion tube was 1.7 m / s (carrier gas supply rate: 10 L / min), and the raw material sludge was supplied by dropping it from the top of the fluidized sand bed (top feed).

[0135] The detailed conditions in Examples 1-1 and 1-2 and Comparative Example 1 were adjusted to the conditions shown in Table 1 below.

[0136] [Table 1]

[0137] 2. Test Results FIG. 5 shows the change in reformer differential pressure over time in Example 1-1 and Comparative Example 1. In Comparative Example 1 (top feed), the reformer differential pressure tended to rise sharply about 4 hours after the start of the supply of raw sludge. In a three-tower circulating fluidized bed apparatus like the above-mentioned test apparatus, when the differential pressure in the reformer becomes equal to or greater than the differential pressure between the "upper surface of the fluidized sand layer of the gasifier and the end of the gasifier standpipe" (about 6 kPa or more in the case of Example 1-1 and Comparative Example 1), the fluidizing gas supplied to the gasifier and the fuel gas generated by the gasification of the raw sludge cannot pass from the reformer gas dispersion nozzle to the reformer, flow from the end of the standpipe into the inside of the standpipe, and are discharged to the reformer outlet without passing through the reformer fluidized sand layer. In that case, the fluidizing medium circulation of the entire circulating fluidized bed stops, and as a result, fuel gas containing a high concentration of tar is generated. Therefore, the test was stopped at about 6 hours in Comparative Example 1.

[0138] After Comparative Example 1 was carried out, the test equipment was cooled, and the gasification furnace and reformer were dismantled to check the inside. The resulting photograph of the gas dispersion plate of the reformer taken from the underside of the gas dispersion plate is shown in FIG. 7. As can be seen from FIG. 7, black powder was attached to the gas dispersion nozzle of the reformer after Comparative Example 1 was carried out. Then, as a result of carrying out industrial analysis (CHNS + ash) of the black powder and XRF analysis of the ash, about 98% by weight of the black powder was olivine component, which is a fluid medium, but the remaining about 2% by weight was char component (a mixture of sludge ash mainly composed of carbon and phosphorus) generated by thermal decomposition of the sludge raw material. The industrial analysis was carried out using a CHN coder (manufacturer: Yanaco Technical Services Co., Ltd., product name: JM11), and the XRF analysis was carried out using an energy dispersive X-ray fluorescence analyzer (manufacturer: Shimadzu Corporation, product name: EDX-8000). Analysis of the black powder showed that it was approximately 98% by weight of olivine, which may lead to the misunderstanding that olivine is the cause of the blockage of the gas dispersion nozzle. However, when a separate experiment was conducted in which a dummy raw material that did not generate char was supplied, it was confirmed that olivine alone did not cause the blockage of the gas dispersion nozzle. From this, it is presumed that the blockage of the gas dispersion nozzle occurs due to the addition of char components to the black powder generated by the fuel gas generation method.

[0139] On the other hand, in Example 1-1, a method was attempted in which the sewage sludge raw material was fed (bottom feed) into the fluidized sand bed of the gasifier, the pyrolysis reaction of the sewage sludge raw material was allowed to proceed inside the fluidized sand bed, and the generated char was discharged to the lower LS while being taken into the fluidized sand. As a result, as shown in FIG. 5, it was found that the reformer differential pressure was kept constant between 4 and 5 kPa for 72 hours. Therefore, in Example 1-1, the operation of the fuel gas generation device could be stably continued even after 72 hours had passed, and the operation could be stopped as planned. In addition, after carrying out Example 1-1 in the same manner as Comparative Example 1, the test device was cooled, and then the gasifier and reformer were disassembled to check the inside. A photograph of the gas dispersion plate of the reformer obtained as a result, taken from the underside of the gas dispersion plate, is shown in FIG. 8. As can be seen from FIG. 8, no accumulation of deposits was observed on the gas dispersion nozzle of the reforming furnace after carrying out Example 1-1, unlike FIG. 7 (gas dispersion nozzle of the reforming furnace after carrying out Comparative Example 1).

[0140] Figure 6 shows the change over time in the reformer differential pressure in Example 1-2. As shown in Figure 6, it was confirmed that in Example 1-2, even when the carrier gas supply amount was reduced to 20 L / min (gas flow rate: 2.2 m / s) compared to Example 1-1, normal raw material supply and furnace operation were possible. Therefore, it was found that the fuel gas generation device and fuel gas generation method disclosed herein reduce the need to increase the carrier gas supply amount and enlarge the device, and thus provide the effect of enabling the device to be made smaller.

[0141] As described above, in Examples 1-1 and 1-2, the raw material is supplied by bottom feeding, and therefore the fuel gas generating apparatus and the fuel gas generating method described in Examples 1-1 and 1-2 correspond to the fuel gas generating apparatus and the fuel gas generating method of the present disclosure. Furthermore, by comparing Examples 1-1 and 1-2 with Comparative Example 1, the fuel gas generating apparatus and the fuel gas generating method of the present disclosure reduce the amount of char scattering in the gasification furnace, and reduce the possibility of the gas dispersion plate of the reformer being clogged by char. As a result, it was found that both the fuel gas generating apparatus and the fuel gas generating method of the present disclosure have the effect of reducing the possibility of normal operation being hindered due to clogging of the gas dispersion nozzle.

[0142] [Example 2: Method for clearing blockage of reformer gas dispersion nozzle] In Example 2, a fuel gas generating apparatus used in the fuel gas generating method according to the second embodiment shown in FIG. 13 was used. Under the same conditions and in the same manner (top feed) as in Comparative Example 1, raw sludge was supplied to the gasification furnace to carry out the fuel gas generating method. As a result, the gas dispersion nozzle of the reformer was clogged. At that time, the supply of raw sludge was stopped. Next, the fluidizing gas was changed to "steam + N 2 " to "air" to combust the char in the nozzle blockage.

[0143] FIG. 9 shows the reformer differential pressure and the CO concentration in the fuel gas in Example 2. 2 As shown in FIG. 9, in Example 2, from the start of the supply of raw sludge to 180 min, H 2 , CO, C.H. 4 At the same time, CO 2 The feed of raw sludge was stopped about 180 minutes after an increase in the differential pressure in the reformer was confirmed about 120 minutes after the start of the feed of raw sludge. Then, about 210 minutes after the start of the feed of raw sludge, the feed gas (fluidizing gas) to the gasifier was changed to "steam + N 2 " to "air." As a result, the CO in the fuel gas 2The concentration increased, and after about 15 minutes had passed since the air supply started, the CO 2 As the generation of the gasification gas stopped, the reformer differential pressure was restored to the baseline, i.e., the level before the supply of the raw sludge. In Example 2, when the supply of the raw sludge was stopped and the supply gas (fluidizing gas) to the gasification furnace was switched to "air", the value of the reformer differential pressure / gasification furnace differential pressure was 5.8 kPa, exceeding 0.6.

[0144] In Example 2, in a fuel gas production method carried out using a triple-tower circulating fluidized bed apparatus, it is shown that as a method for resolving blockage of the gas dispersion nozzle, the fluidizing gas supplied to the gasifier is temporarily switched to air, i.e., the oxygen concentration of the fluidizing gas is increased, thereby resolving blockage of the gas dispersion nozzle due to char and enabling the restart of fuel gas production. From this, it was found that another fuel gas production apparatus and another fuel gas production method disclosed herein have the effect of reducing the possibility that normal operation will be hindered due to blockage of the gas dispersion nozzle.

[0145] Moreover, in the fuel gas generation method of the present disclosure, which is a fuel gas generation method carried out using a triple-tower circulating fluidized bed apparatus, it is clear that the clogging of the gas dispersion nozzle by char is eliminated by increasing the oxygen concentration of the fluidizing gas supplied to the gasification furnace. Therefore, it has been found that an apparatus that corresponds to the fuel gas generation apparatus of the present disclosure and includes an oxygen concentration adjusting unit that adjusts the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace has the effect of eliminating the interruption of fuel gas generation caused by the clogging of the gas dispersion nozzle and making it possible to resume fuel gas generation.

[0146] It has been found that a method which corresponds to the fuel gas generation method disclosed herein and which includes an oxygen concentration adjustment step of adjusting the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace using the oxygen concentration adjustment unit, in which the oxygen concentration adjustment step includes increasing the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace when the value of the differential pressure of the reformer / the differential pressure of the gasification furnace exceeds 0.6, has the effect of being able to preferably resolve interruption of fuel gas generation due to clogging of the gas dispersion nozzle, and also has the effect of being able to avoid a decrease in the amount of fuel gas generated due to combustion of pyrolysis gas by not increasing the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace until the gas dispersion nozzle becomes clogged. [Industrial Applicability]

[0147] A fuel gas generation apparatus and a fuel gas generation method according to one embodiment of the present disclosure are suitable for use in producing fuel gas using various organic raw materials such as sewage sludge (dewatered sludge, dried sludge), biomass, coal, waste, petroleum residues, and heavy oil. [Explanation of symbols]

[0148] 1 Tower circulating fluidized bed equipment 1-a Reformer 1-b Gasifier 1-c Combustion furnace 1-d Raw material supply port, another raw material supply port 1-e Fluid sand layer 1-f Standpipe 1-g Gas distribution plate 1-h Gas dispersion nozzle 1-i Upper Loop Seal (LS) 1-j Lower Loop Seal (LS) 1-k riser 1-l Cyclone 1-m Equipment for supplying fluidized sand from the gasifier to the combustion furnace 1-n Equipment for supplying fluidized sand from the combustion furnace to the reformer 1-o Raw material insertion tube 1-p Raw material supply feeder 1-q Raw material supply valve 1-r Char outlet 2 Drying equipment 3 Gas purification equipment (for producing purified hydrogen) 4. Combustion exhaust gas heat recovery equipment 5. Fuel gas heat recovery equipment 6 Gas engine generator 7 Air for combustion furnace 8. Steam for gasification 9. Dewatered sludge 10 Drying device carrier air 11 Dried sludge (for auxiliary combustion) 12 Fuel gas refinery off-gas 13 Dried sludge (for fuel gas production) 14 Refined Hydrogen 15 Combustion exhaust gas 16 Gas engine combustion exhaust gas 17 Fuel gas (furnace auxiliary fuel) 18 Electricity 19 Dry exhaust gas drain 20 Drying equipment exhaust gas 21 Air supply valve (gasifier) 22 Air supply valve (raw material insertion tube) 23 High concentration CO 2 Gas (for raw sludge carrier) 24 Gas separation off-gas 25 Gas purification equipment (for gas engine power generation) 26 Raw material insertion tube carrier gas 27 Differential pressure gauge 28 Differential pressure gauge 29 Steam supply valve 30 Gas analyzer (CO 2 concentration measurement) 31 Carrier gas supply valve 32 Oxygen concentration adjustment unit

Claims

1. a gasification furnace for pyrolyzing the raw material; a reformer for reforming the pyrolysis gas produced in the gasification furnace to generate a fuel gas; A fuel gas generating apparatus comprising: a combustion furnace that combusts the pyrolysis residue transferred from the gasification furnace, The reformer is installed above the gasifier, a gas dispersion nozzle for transferring the pyrolysis gas to the reforming furnace is provided between the reforming furnace and the gasification furnace; The gasification furnace has a fluidized sand bed therein and a raw material supply port for supplying the raw material into the fluidized sand bed.

2. The fuel gas generation apparatus of claim 1, wherein when the height of a char discharge port, which discharges the pyrolysis residue from the gasification furnace to the combustion furnace, from the bottom surface of the gasification furnace is taken as 100%, the raw material supply port is provided at a position that is 30% to 70% away from the char discharge port toward the bottom surface of the gasification furnace.

3. a raw material insertion pipe for transporting the raw material is connected to the raw material supply port; 2. The fuel gas generation apparatus according to claim 1, wherein the raw material insertion pipe is disposed in the gasification furnace at an angle of 30 degrees or more and 60 degrees or less with respect to the horizontal direction.

4. The fuel gas generation apparatus according to claim 1 , further comprising a carrier gas supplying unit that supplies a carrier gas to the raw material supplied into the fluidized sand bed.

5. 2. The fuel gas generation apparatus of claim 1, wherein the fluidized sand bed comprises one or more of the group consisting of olivine, alumina, and calcined lime.

6. The fuel gas generation apparatus according to claim 4 , further comprising a fuel gas supply pipe that supplies a portion of the fuel gas as at least a portion of the carrier gas to the carrier gas supply section.

7. The CO contained in the fuel gas is ２ a conversion section for converting the gas into a converted gas; From the conversion gas, H ２ And, ２ and C.H. ４ and an off-gas separation unit for separating the off-gas from the off-gas, a supply pipe for supplying a portion of the off-gas to the carrier gas supply unit as at least a portion of the carrier gas to the carrier gas supply unit; and The fuel gas generating apparatus according to claim 4 , further comprising an off-gas supply pipe for supplying another portion of the off-gas to the combustion furnace.

8. The combustion exhaust gas discharged from the combustion furnace is used to ２ Separating CO ２ A separation section, and The CO ２ CO separated in the separation section ２ is supplied to the carrier gas supply unit as at least a part of the carrier gas; ２ The fuel gas generator of claim 4 comprising a supply pipe.

9. The fuel gas generation device according to claim 1 , further comprising an oxygen concentration adjusting unit that adjusts the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace.

10. A method for generating fuel gas, which is carried out using the fuel gas generating apparatus according to any one of claims 1 to 9, A raw material supplying step of supplying the raw material into the fluidized sand bed through the raw material supply port; a pyrolysis gas generating step of causing pyrolysis of the raw material to proceed inside the fluidized sand bed to obtain a pyrolysis gas; and A fuel gas generating method comprising: a reforming step of supplying the pyrolysis gas obtained in the pyrolysis gas generating step to the reforming furnace and reforming the pyrolysis gas to generate a fuel gas.

11. A method for generating fuel gas, which is carried out using the fuel gas generating apparatus according to claim 4, comprising: The fuel gas generation method according to claim 10, further comprising a carrier gas supplying step of supplying a carrier gas having a flow velocity of 1.5 m / s or more and 5.0 m / s or less to the raw material supplied to the inside of the fluidized sand bed using the carrier gas supplying unit.

12. A method for generating fuel gas, which is carried out using the fuel gas generating apparatus according to claim 9, comprising: an oxygen concentration adjusting step of adjusting the oxygen concentration contained in the fluidizing gas supplied to the gasification furnace by using the oxygen concentration adjusting unit; The fuel gas generation method according to claim 10, wherein in the oxygen concentration adjustment process, when the value of the differential pressure of the reformer furnace / the differential pressure of the gasification furnace exceeds a predetermined standard value, the oxygen concentration contained in the flowing gas supplied to the gasification furnace is increased.

13. The fuel gas generation method according to claim 10, further comprising a cleaning process for stopping the supply of the raw material to the gasification furnace and the supply of gas containing water vapor for pyrolyzing the raw material to the gasification furnace when the value of the differential pressure in the reformer furnace / the differential pressure in the gasification furnace exceeds a predetermined standard value, thereby stopping the pyrolysis gas generation process, and then supplying a gas containing oxygen to the gasification furnace to reduce the value of the differential pressure in the reformer furnace / the differential pressure in the gasification furnace.

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