Exhaust gas processing apparatus and Exhaust gas processing method

Abstract

To solve the aforementioned problem, the present invention provides an exhaust gas treatment device and an exhaust gas treatment method that can be easily installed in existing facilities and enable the cleaning of combustion gas at a low cost. The present invention relates to a gas treatment device for reforming combustion gas generated in a combustion furnace that burns biomass fuel, the gas treatment device comprising a particle supply device that supplies coal combustion material into the combustion gas.

Description

Technology Field

[0001] The present invention relates to an exhaust gas treatment device and an exhaust gas treatment method capable of reforming combustion gas generated in a combustion furnace. Background Technology

[0002] Recently, in order to secure fuel, there is a growing demand for power generation using waste fuels such as waste tires and waste plastics, as well as biomass fuels other than construction waste wood materials and wood materials. For such power generation mechanisms, for example, a technology utilizing a boiler can be cited, which is equipped with a combustion furnace that burns a material to be combusted and generates saturated steam, and which is connected to the combustion furnace and superheats the saturated steam generated in the furnace using the combustion gas generated in the furnace to drive a turbine for power generation. In addition, as an example of such technology, a circulating fluidized bed boiler equipped with a fluidized bed (hereinafter referred to as a "CFB boiler") is used.

[0003] In facilities using boilers, filtration means (dust collection means), such as bag filters, are used to remove harmful substances from the combustion gas when the combustion gas generated in the combustion furnace is discharged out of the facility. Regarding technologies for bag filters, for example, a technology for collecting dust by forming a filter chamber on the surface of a bag filter using zeolite, or a technology for providing a duct section with a throttle section so that dust and the adsorbent in the exhaust gas are uniformly mixed (for example, see Patent Documents 1 and 2 below). Prior art literature

[0004] Patent Document 1: Japanese Published Patent Application No. Hei 06-343821 Patent Document 2: Japanese Published Patent Application No. 2000-262842 The problem to be solved

[0005] A "filter cloth" is installed in the bag filter for dust collection, and as the filter cloth, for example, a material made of polyphenylene sulfide resin (hereinafter referred to as "PPS") or a material made of polytetrafluoroethylene (PTFE) is widely used.

[0006] Meanwhile, when biomass fuel is burned, NO x It is known that this is prone to occurring. In particular, the combustion gases of biomass fuels contain a large amount of NO2. However, sulfur-based materials such as PPS are known as suitable materials for filter cloths due to the balance between running costs and performance. However, since sulfur-based materials such as PPS tend to undergo oxidative degradation when NO2 is present in the combustion gases, various methods are employed to remove NO2 from the combustion gases. For example, techniques to remove NO2 from combustion gases by adding activated carbon or zeolite to the combustion gases are known. However, since activated carbon is easily combusted, it is difficult to blow it into the combustion gases during the process from combustion to the bag filter in a CFB boiler. Furthermore, zeolite requires costs for its manufacturing and procurement, as well as for the equipment to supply it to the combustion furnace.

[0007] The present invention aims to provide an exhaust gas treatment device and an exhaust gas treatment method that can be easily installed in existing facilities and enable the cleaning of combustion gases at low cost, in order to solve the aforementioned problem. means of solving the problem

[0008] That is, the present invention is as follows.

[0009] <1> An exhaust gas treatment device for reforming combustion gas generated in a combustion furnace that completely burns biomass fuel, comprising a particle supply device for supplying coal combustion material (ash) into the combustion gas.

[0010] <2> The above, in which the temperature of the combustion gas exceeds 600℃ <1> Exhaust gas treatment device described in

[0011] <3> The particle supply device above supplies the coal combustion material into the combustion furnace <1> or <2> Exhaust gas treatment device described in

[0012] <4> The particle supply device, in a combustion gas flow path downstream of the combustion furnace, supplies the coal combustion material into the combustion gas. <1> To the above <3> An exhaust gas treatment device described in any one of the following.

[0013] <5> A bag filter is provided downstream of the above combustion furnace, and the particle supply device supplies the coal combustion material into the combustion gas upstream of the bag filter. <1> To the above <4> An exhaust gas treatment device described in any one of the following.

[0014] <6> The above bag filter comprises a filter cloth made of polyphenylene sulfide resin. <5> Exhaust gas treatment device described in

[0015] <7> An exhaust gas treatment method for reforming combustion gas generated in a combustion furnace that burns biomass fuel, comprising a process of supplying coal combustion material to the combustion gas.

[0016] <8> The above, in which the temperature of the combustion gas exceeds 600℃ <7> Exhaust gas treatment method described in

[0017] <9> The above coal combustion material, supplied into the above combustion furnace <7> or the above <8> Exhaust gas treatment method described in

[0018] <10> The above coal combustion material, supplied into the combustion gas downstream of the combustion furnace <7> To the above <9> Exhaust gas treatment method described in any one of the following.

[0019] <11> A bag filter is provided downstream of the above combustion furnace, and the above coal combustion material is supplied to the combustion gas upstream of the bag filter. <7> To the above <10> Exhaust gas treatment method described in any one of the following.

[0020] <12> The above bag filter comprises a filter cloth made of polyphenylene sulfide resin. <11> Exhaust gas treatment method described in Effects of the invention

[0021] According to the present invention, an exhaust gas treatment device and an exhaust gas treatment method can be provided that can be easily installed in existing facilities and enable the cleaning of combustion gases at a low cost. Brief explanation of the drawing

[0022] FIG. 1 is a schematic diagram showing a combustion facility of a first embodiment of the present invention. FIG. 2 is a schematic diagram showing a combustion facility of a second embodiment of the present invention. Figure 3 is a graph showing the relationship between the temperature of the combustion gas into which coal combustion material is introduced and the NO2 removal rate. Specific details for implementing the invention

[0023] Hereinafter, with reference to the drawings, forms for implementing the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. However, the following embodiments are examples for explaining the present invention and are not intended to limit the present invention to the following contents. The present invention may be implemented with appropriate modifications within the scope of its gist. However, identical elements are given the same reference numerals, and redundant descriptions are omitted. Furthermore, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specifically stated. Additionally, the dimensional ratios in the drawings are not limited to the ratios shown.

[0024] (First embodiment)

[0025] A combustion facility equipped with an exhaust gas treatment device of the first embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing a combustion facility of the first embodiment of the present invention.

[0026] As shown in FIG. 1, the combustion facility (10) is equipped with a combustion furnace (20) into which biomass fuel, which is the subject of combustion, is supplied and which completely burns the biomass fuel inside the furnace, and a heat recovery unit (30) that recovers heat from the combustion gas generated in the combustion furnace (20). In addition, the combustion facility (10) is equipped with a bag filter (40) downstream of the combustion furnace (20) and the heat recovery unit (30) to remove harmful substances from the combustion gas discharged from the heat recovery unit (30). Furthermore, the combustion furnace (20) is equipped with a biomass fuel supply device (22) that supplies biomass fuel into the furnace and a particle supply device (50) that supplies coal combustion material into the combustion gas. In this embodiment, the particle supply device (50) serves as an exhaust gas treatment device. However, in FIG. 1, the thick arrow indicates the direction of flow of the combustion gas.

[0027] The combustion facility (10) is not specifically limited, but can be exemplified by a so-called boiler that superheats steam through heat exchange between the combustion gas generated in the combustion furnace (20) and a superheater or economizer installed in the heat recovery unit (30) and uses it for power generation. In addition, the combustion facility (10) is not specifically limited, but can be any of the following: a once-through boiler, a circulation boiler, or a heat recovery boiler mainly used for thermal power generation business, as well as a circulating fluidized bed boiler (CFB) or a fluidized bed boiler (BFB) used for industrial purposes.

[0028] As shown in FIG. 1, the combustion furnace (20) is configured, for example, as a vertically elongated conventional furnace, and burns biomass fuel supplied from a biomass fuel supply unit (22) inside the furnace.

[0029] When the biomass fuel supplied from the biomass fuel supply unit (22) to the combustion furnace (20) is burned, combustion gas is generated inside the furnace. Also, although not explicitly shown, water pipes may be installed on the walls of the combustion furnace (20), and saturated steam may be generated by exposing the water pipes to the combustion gas inside the combustion furnace (20). The combustion gas contains NO, such as NO2, generated by the combustion of the biomass fuel. X (Nitrogen oxides) are included. In addition, the combustion gas contains low-melting point molten salts such as KCl and NaCl generated by the combustion of biomass fuel, and solid particles such as ash generated by combustion. The furnace temperature is not particularly limited, but is approximately 800 to 1000°C. The combustion gas generated in the combustion furnace (20) is supplied to the heat recovery unit (30) while containing these nitrogen oxides, molten salts, and ash.

[0030] As shown in FIG. 1, the combustion facility (10) is equipped with a particle supply device (50) that supplies coal combustion material into the combustion gas. When the coal combustion material is introduced into the combustion gas, NO in the combustion gas x The concentration (especially NO2) can be reduced. As for the coal combustion material, there are no specific restrictions on the method of acquisition, but for example, clinker ash (bottom ash, furnace ash), fly ash, etc. generated from pulverized coal boilers (PC boilers) or other boilers (e.g., fluidized bed boilers, etc.) may be used. However, ash recovered from PC boilers may be referred to as PC ash. The coal combustion material used in this embodiment may be the coal combustion material recovered as waste from PC boilers, etc. outside the system, without special pretreatment.

[0031] As for the coal combustion material, although not specifically limited, it is desirable that the melting point be higher than the temperature of the supplied combustion gas, for example, that the melting point be higher than 800 to 1000°C.

[0032] In addition, it is preferable that the coal combustion material consists of particles with an average particle size of 10 to 20 μm.

[0033] Also, coal combustion material is difficult to combust compared to activated carbon. For this reason, the combustion facility (10) can be configured to be introduced into the combustion gas at any stage in the process from the combustion furnace (20) to the bag filter (40). For example, in FIG. 1, a particle supply device (50) is provided in the combustion furnace (20), but the installation location and number of said device are not limited to this, and it may be installed in any location such as the combustion gas flow path (flue) connecting the combustion furnace (20) and the heat recovery unit (30), a device such as a cyclone described later (the area indicated by arrow A in FIG. 1), the heat recovery unit (30) (for example, the area indicated by arrow B in FIG. 1), and the flue connecting the heat recovery unit (30) and the bag filter (40) (for example, the area indicated by arrow C in FIG. 1). However, in cases where coal combustion ash is introduced into combustion gas exceeding 600℃, the NO of the coal combustion ash x The reduction effect (cleaning effect) of the concentration (especially NO2) is improved. In this regard, although not specifically limited, it is preferable that the coal combustion material be introduced into a part of the combustion facility (10) where the temperature of the combustion gas exceeds 600°C (preferably 610 to 900°C, more preferably 650 to 900°C). Also, as in this embodiment, it is preferable that the particle supply device (50) be installed upstream of the bag filter (40) (in particular, a bag filter equipped with a filter cloth made of PPS).

[0034] In addition, since there are no special restrictions on the means and conditions for introducing coal combustion materials, there is no need to install new special equipment to introduce coal combustion materials. For this reason, for example, in existing equipment, a particle supply device (50) can be installed to supply coal combustion materials from a supply port, such as one provided in the combustion furnace (20) for supplying sand or additives.

[0035] Additionally, the particle supply device (50) can be electrically coupled with a control unit that omits city and configured to control the timing or amount of supply of coal combustion material.

[0036] Combustion gas discharged from the combustion furnace (20) is supplied to the heat recovery unit (30). A flue serving as a flow path for the combustion gas is provided within the heat recovery unit (30), and the heat recovery unit (30) is configured to recover heat from the combustion gas passing through the flue. Additionally, a superheater, an economizer, a gas air heater, etc., may be installed within the flue, and steam pipes, which are not shown, are installed in these superheaters or economizers. Saturated steam generated by the heat of the combustion furnace (20) flows through the steam pipes, and the saturated steam is superheated through heat exchange between the combustion gas passing through the flue and the superheater, etc. The combustion gas discharged from the heat recovery unit (30) is discharged to a bag filter (40) installed downstream of the heat recovery unit (30). In addition, the saturated steam superheated by the heat recovery unit (30) can be used, for example, to drive a power generation turbine.

[0037] The bag filter (40) is a device that collects and purifies molten salt or solid particles in the combustion gas before discharging the combustion gas out of the combustion facility (10). A filter cloth is installed inside the bag filter (40) as a dust collection means. As for the filter cloth, materials made of PSS or PTFE can be used as described above, but from the perspective of balancing running cost and performance, it is preferable to use a filter cloth made of sulfur-based materials such as PSS. Known materials can be appropriately selected and used for the bag filter and the filter cloth.

[0038] The combustion gas discharged from the bag filter is sent to a downstream device as exhaust gas as needed, and then discharged outside the facility.

[0039] As described above, in this embodiment, the biomass fuel is burned in a combustion furnace (20) that burns the biomass fuel completely, and by supplying a coal combustion material to the combustion gas generated by the combustion of the biomass fuel, the combustion gas is reformed (NO x The concentration can be reduced, thereby allowing the combustion gas to be cleaned. In addition, the coal combustion material used in this embodiment can be utilized as is, recovered as waste from PC boilers, etc., without undergoing special pretreatment. Therefore, raw material costs can be kept low.

[0040] In addition, as described above, the coal combustion material in this embodiment has no particular restrictions on the means and conditions for introduction, so, for example, a particle supply device (50) can be installed using each supply port that is already installed in existing facilities. Because of this, there is no need to install new special facilities, so the facility cost (e.g., initial introduction cost of facilities) can be kept low.

[0041] In this embodiment, the coal combustion material can be configured to be supplied to combustion gas exceeding 600°C. If the temperature of the combustion gas to which the coal combustion material is supplied exceeds 600°C, compared to the case where the coal combustion material is supplied to combustion gas at 600°C or lower, NO produced by the coal combustion material x The removal effect can be improved.

[0042] In addition, when the particle supply device (50) is installed to supply coal combustion material into the combustion furnace (20), typically, since the temperature of the combustion gas inside the combustion furnace (20) exceeds 600℃, there is no need to introduce special equipment to raise the temperature of the combustion gas to exceed 600℃. For this reason, the combustion equipment (10) [produces] NO from the coal combustion material x The concentration reduction effect can be effectively improved.

[0043] In addition, although the present embodiment is shown as being supplied with coal combustion material within the combustion furnace (20), the present embodiment is not limited to such an embodiment. As described above, a particle supply device (50) may be installed to supply coal combustion material into the combustion gas in a part other than the combustion furnace (20) (a combustion gas path downstream of the combustion furnace) instead of or in addition to the combustion furnace (20). For example, if a particle supply device (50) is installed to supply coal combustion material to the combustion gas path (the part indicated by arrows A to C in Fig. 1) until the combustion gas discharged from the combustion furnace (20) reaches the bag filter, for example, the coal combustion material can be supplied to the combustion gas without hindering the combustion of biomass fuel in the combustion furnace (20). In addition, in areas other than the combustion furnace (20), since the pressure in the combustion gas flow path is lower than in the furnace, the coal combustion material can be supplied to the combustion gas more easily than when introduced into the combustion furnace (20).

[0044] In this embodiment, a bag filter (40) is provided downstream of the combustion furnace (20). In addition, in this embodiment, a particle supply device (50) is installed to supply coal fuel into the combustion gas in a combustion gas path upstream of the bag filter (40). Accordingly, the combustion gas supplied to the bag filter (40) contains NO in the gas due to the coal combustion material. x Since the concentration is sufficiently reduced, a filter cloth made of PPS (polyphenylene sulfide resin), which is prone to oxidative degradation with respect to NO2 in the combustion gas, can be used as a bag filter (40). Sulfur-based materials such as PPS have an excellent balance of running cost and performance among filter cloth materials. Therefore, by using a filter cloth made of PPS as a bag filter (40), the running cost of the combustion equipment (10) can be reduced while maintaining exhaust gas cleaning performance.

[0045] (Second embodiment)

[0046] A combustion facility equipped with an exhaust gas treatment device according to a second embodiment will be described with reference to FIG. 2. FIG. 2 is a schematic diagram showing a combustion facility according to a second embodiment of the present invention. In this embodiment, a combustion facility equipped with a circulating fluidized bed boiler (CFB) as a combustion furnace will be described as an example.

[0047] As shown in FIG. 2, the combustion facility (100) is equipped with a combustion furnace (120) into which biomass fuel is supplied and which completely burns the biomass fuel inside the furnace, a cyclone (125) that separates solids from the combustion gas from which the biomass fuel is burned, and a heat recovery unit (130) that recovers heat from the combustion gas. In addition, the combustion facility (100) is equipped with a bag filter (140) downstream of the combustion furnace (120) and the heat recovery unit (130) to remove harmful substances in the combustion gas discharged from the heat recovery unit (130). Furthermore, the combustion furnace (120) is equipped with a fuel supply device (122) that supplies biomass fuel into the furnace and a particle supply device (150) that supplies coal combustion material into the furnace. In this embodiment, the particle supply device (150) serves as an exhaust gas treatment device.

[0048] The combustion furnace (120) is configured as a vertically elongated conventional furnace and burns biomass fuel supplied from a fuel supply unit (122) inside the furnace. The combustion furnace (120) is a fluidized bed furnace that burns biomass fuel while flowing it in a fluidized bed (120A). In addition, the combustion furnace (120) is a circulating fluidized bed furnace in which solid matter of a predetermined particle size or larger is returned by a cyclone (125) as described later. The temperature inside the combustion furnace (120) is not particularly limited, but the temperature of the combustion gas can be set to approximately 800 to 1000°C.

[0049] When the biomass fuel supplied from the fuel supply unit (122) to the combustion furnace (120) is burned, combustion gas is generated. As described above, the combustion gas contains solid particles such as low-melting point molten salt or ash generated by combustion, and the combustion gas generated in the combustion furnace (120) is sent to the cyclone (125) while containing these molten salts and ash.

[0050] As shown in FIG. 2, the combustion furnace (120) is equipped with a particle supply device (150) that supplies coal combustion material into the combustion gas. As coal combustion material, PC material recovered from an external PC boiler may be used. In this embodiment, the particle supply device (150) is installed to supply coal combustion material from a supply port through which sand or additives used in the fluidized bed (120A) are supplied. In addition, the particle supply device (150) is electrically coupled with a control unit (not shown) and the timing and amount of supply of coal combustion material are controlled. NO in the combustion gas due to the supply of coal combustion material x The concentration of is reduced.

[0051] The cyclone (125) is a solid gas separation device that separates solid particles with a particle size greater than a predetermined size discharged from the combustion furnace (120) from the combustion gas and returns them to the combustion furnace (120). The cyclone (125) separates solid particles with a particle size greater than a predetermined size from the combustion gas and returns them to the combustion furnace (120), and also sends the combustion gas from which these solid particles have been separated to the downstream heat recovery unit (130). The particle size of the solid particles separated by the cyclone (125) is not particularly limited, but can be set to, for example, about 20 μm. The coal combustion material supplied into the combustion furnace (120) by the particle supply device (150) is discharged together with the combustion gas to the downstream heat recovery unit (130).

[0052] As described above, the combustion gas discharged from the cyclone (125) is sent to the heat recovery unit (130). In the heat recovery unit (130), as in the first embodiment, a flue (not shown) serving as the flow path for the combustion gas, a superheater, an economizer, a gas air heater, etc. are installed, and the unit is configured to recover heat from the combustion gas passing through the flue. Likewise, a steam pipe (not shown) is installed in the superheater or the economizer. Saturated steam generated by the heat of the combustion furnace (120) flows through the steam pipe, and the saturated steam is superheated by heat exchange between the combustion gas and the superheater, etc. The combustion gas discharged from the heat recovery unit (130) is discharged to a bag filter (140) installed downstream of the heat recovery unit (130). In addition, the saturated steam superheated by the heat recovery unit (130) can be used, for example, to drive a power generation turbine.

[0053] The bag filter (140) is a device that collects and purifies molten salt or solid particles in the combustion gas before discharging the combustion gas out of the combustion facility (100). A filter cloth made of PSS is installed inside the bag filter (40) as a dust collection means. In this embodiment, NO in the combustion gas supplied to the bag filter (140) x Since the concentration is sufficiently reduced, oxidative deterioration of the PPS filter cloth can be suppressed.

[0054] The combustion gas discharged from the bag filter is sent to a downstream device as exhaust gas as needed, and then discharged outside the facility.

[0055] As described above, in this embodiment, the biomass fuel is burned in a combustion furnace (120) that burns the biomass fuel completely, and by supplying a coal combustion material to the combustion gas generated by the combustion of the biomass fuel, the combustion gas is reformed (NO xThe concentration can be reduced, thereby allowing the combustion gas to be cleaned. In addition, the coal combustion material used in this embodiment can be used as is, recovered as waste from PC boilers, without special pretreatment, so raw material costs can be kept low. Furthermore, the combustion furnace in this embodiment is a circulating fluidized bed boiler, and the exhaust gas treatment device (particle supply device (150)) of this embodiment is installed so that the coal combustion material can be supplied from a supply port through which sand or additives used in the fluidized bed (120A) are supplied. Therefore, there is no need to install new special equipment, so equipment costs can be kept low.

[0056] Also, in this embodiment, since coal combustion material is supplied to a combustion furnace (120) in which the temperature of the combustion gas exceeds 600℃, particularly NO x The concentration reduction effect is excellent. In addition, in this embodiment, a bag filter (140) using a filter cloth made of PPS is provided. The combustion gas supplied to the bag filter (140) is NO caused by the coal combustion material supplied to the combustion furnace (120). x Since the concentration is sufficiently reduced, in this embodiment, the filter cloth made of PPS is less likely to oxidize and deteriorate, so the running cost of the combustion facility (10) is excellent.

[0057] However, in this embodiment, a particle supply device (150) is installed to supply coal combustion material into the combustion furnace (120) from a supply port through which sand or additives used in the fluidized bed (120A) are supplied. However, as described above, the supply location of the coal combustion material is not limited to the said location. For example, a new supply port may be provided at the connection part (flue) between the cyclone (125) and the combustion furnace (120), and the coal combustion material may be supplied from said supply port. Alternatively, a supply port may be provided at the cyclone (125), the heat recovery part (130), or the connection part between these devices, and the particle supply device (150) may be installed to supply the coal combustion material from said supply port.

[0058] The embodiments described through the embodiments of the invention described above may be utilized by appropriately combining, modifying, or improving them according to the intended use. Furthermore, the present invention is not limited to the descriptions of the embodiments described above.

[0059] Examples

[0060] Hereinafter, using the examples, the cleaning effect (NO x The concentration reduction effect is explained. However, the embodiments of the present invention are not limited to the following examples.

[0061] Combustion experiments of biomass fuel were conducted using a CFB boiler, and the NO of the combustion gas was measured with and without the input of coal combustion material. x The concentrations of , NO, and NO2 were measured. The measured values ​​are shown in the table below. PKS (imported coconut shells) was used as the biomass fuel, and PC ash recovered from a PC boiler was used as the coal combustion material. The coal combustion material was 2 g / m³ relative to the combustion gas. 3 It was added to such an extent. Also, the temperature of the combustion gas was 160℃. As shown in the table below, it can be seen that when coal combustion material is added, NO2 in NOX is reduced compared to the case where coal combustion material is not added.

[0062] [Table 1]

[0063]

[0064] In addition, the relationship between the temperature of the combustion gas into which coal combustion material is introduced and the NO2 removal rate is shown in Figure 3.

[0065] FIG. 3 shows the NO2 removal rate when PC material (50g) is supplied into the combustion gas inside the furnace for combustion furnaces with furnace temperatures of 149°C, 610°C, and 850°C, respectively. The NO2 removal rate was calculated by also taking into account the NO2 removal rate when PC material is not supplied, which was calculated from the results of the blank test. As a result, the NO2 removal rate was 40% for furnace temperature 149°C, 42% for furnace temperature 610°C, and 91% for furnace temperature 850°C. However, in this test, the furnace temperature can be considered as the temperature of the combustion gas.

[0066] As shown in Figure 3, it can be seen that the NO2 removal rate of the sample at a furnace temperature of 850°C is significantly improved compared to the sample at a furnace temperature of 600°C or lower. Explanation of the symbols

[0067] 10, 100… Combustion equipment 20, 120… combustion furnace 22, 122… Biomass fuel supply 30, 130… Heat recovery unit 40, 140… bag filter 50, 150… particle supply device 125… Cyclone

Claims

Claim 1 An exhaust gas treatment device for reforming combustion gas generated in a combustion furnace that burns biomass fuel, comprising a particle supply device that supplies coal combustion material into the combustion gas, wherein the temperature of the combustion gas to which the coal combustion material is supplied is 610°C or higher and 900°C or lower, wherein the particle supply device is provided in a combustion gas flow path downstream of the combustion furnace and supplies the coal combustion material into the combustion gas downstream of the combustion furnace, and further wherein a bag filter is provided downstream of the combustion furnace and the particle supply device supplies the coal combustion material into the combustion gas upstream of the bag filter, thereby reforming the combustion gas to suppress oxidative deterioration of sulfur-based materials. Claim 2 In claim 1, the exhaust gas treatment device wherein the bag filter comprises a filter cloth made of polyphenylene sulfide resin. Claim 3 A method for treating exhaust gas by reforming combustion gas generated in a combustion furnace that burns biomass fuel, comprising a process of supplying a coal combustion material into the combustion gas, wherein the temperature of the combustion gas into which the coal combustion material is supplied is 610°C or higher and 900°C or lower, wherein the coal combustion material is supplied into the combustion gas downstream of the combustion furnace, and further wherein a bag filter is provided downstream of the combustion furnace, and the coal combustion material is supplied into the combustion gas upstream of the bag filter, thereby reforming the combustion gas to suppress oxidative deterioration of sulfur-based materials. Claim 4 In paragraph 3, the exhaust gas treatment method wherein the bag filter comprises a filter cloth made of polyphenylene sulfide resin. Claim 5 In paragraph 1 or 2, the combustion furnace is an exhaust gas treatment device in which the combustion furnace is a circulating fluidized bed boiler. Claim 6 In paragraph 1 or 2, the combustion furnace is an exhaust gas treatment device in which the combustion furnace is a bubbling fluidized bed boiler. Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete

Images