Furnace system

Abstract

To provide an efficiently operating furnace system comprising a carbonization furnace and an electric furnace.SOLUTION: A furnace system 1 comprises: a carbonization section 20 for producing carbonized material in a carbonization furnace using biomass as a raw material; and a molten steel section 50 for producing steel in an electric furnace using steel scrap as a raw material, wherein the carbonized material produced in the carbonization section 20 is supplied to the molten steel section 50, and the steel scrap is preheated by heat derived from combustion gas from the carbonization section 20.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a furnace system including a carbonization furnace and an electric furnace for melting iron scrap. [Background technology]

[0002] In recent years, systems that combine a carbonization furnace with other functions have become available. Examples of such prior art include the following:

[0003] First, there is a biomass power generation system that includes a carbonization furnace that carbonizes woody biomass, a pyrolysis furnace that generates pyrolysis gas from the carbonized material and combustion gas obtained in the carbonization furnace, and a power generation device that obtains electricity using water gas obtained by cleaning the pyrolysis gas, and is characterized by having an air supply control unit that controls the amount of air supplied to the carbonization furnace, and supplying combustion gas whose temperature is controlled by the amount of air supplied to the pyrolysis furnace (Patent Document 1).

[0004] Another example is an iron-making apparatus that is equipped with an electric furnace operated by electricity from a fuel cell, in which biomass supplied to the electric furnace is used as a reducing agent, and hydrogen gas derived from the product gas of the biomass is supplied to the fuel cell, which serves as the power source for the electric furnace (Patent Document 2).

[0005] Here, the system described in Patent Document 1 is not intended to be combined with an electric furnace. In addition, the system described in Patent Document 2 uses biomass and auxiliary materials in an electric furnace, but is not intended to be combined with a carbonization furnace.

[0006] Both carbonization furnaces and electric furnaces require high energy and generate combustion heat and by-products. Simply combining these types of equipment results in large losses of energy and by-products. In other words, an efficient furnace system that combines a carbonization furnace and an electric furnace and reduces losses of heat and other waste generated by each furnace is required. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2017-132969 A [Patent Document 2] JP 2023-13386 A Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide an efficient furnace system in which loss of heat and the like generated in each furnace is reduced. [Means for solving the problem]

[0009] A first invention is a furnace system comprising a carbonization section which uses biomass as a raw material to produce char in a carbonization furnace, and a molten steel section which uses iron scrap as a raw material to produce steel in an electric furnace, the furnace system supplies the char produced in the carbonization section to the molten steel section and preheats the iron scrap with heat originating from combustion gas from the carbonization section. A second invention is a furnace system comprising a carbonization section which uses biomass as a raw material to produce char in a carbonization furnace, a pyrolysis section which pyrolyzes the char produced in the carbonization section to produce water gas in a pyrolysis furnace, and a molten steel section which uses iron scrap as a raw material to produce steel in an electric furnace, the furnace system supplies the water gas produced in the pyrolysis section to the molten steel section and preheats the iron scrap with heat originating from combustion gas from the carbonization section. The third invention is a furnace system including a carbonization section that uses biomass as a raw material to generate charcoal in a carbonization furnace, a pyrolysis section that uses a pyrolysis furnace to pyrolyze the charcoal generated in the carbonization section to generate water gas, and a molten steel section that uses scrap iron as a raw material to generate steel in an electric furnace, the furnace system appropriately supplies the charcoal generated in the carbonization section to the pyrolysis section and / or the molten steel section, supplies the water gas generated in the pyrolysis section to the molten steel section when the charcoal is supplied to the pyrolysis section, and preheats the scrap iron with heat originating from the combustion gas from the carbonization section. The fourth invention is the furnace system according to any one of the first to third inventions, which supplies heat originating from the combustion gas from the carbonization section and / or the molten steel section to a desired part in the furnace system. The fifth invention is the furnace system according to the fourth invention, which is provided with a heat circulation path for circulating and utilizing the heat originating from the combustion gas in the furnace system. Effect of the Invention

[0010] In the present invention, by preheating the iron scrap with the combustion gas generated in the carbonization section and supplying the carbide produced in the carbonization section to the molten steel section, heat loss and other losses can be reduced, and the system is expected to become more efficient. In addition, in the present invention, by supplying the carbide produced in the carbonization section to the pyrolysis section and further generating water gas and supplying it to the molten steel section, the system is expected to become more efficient. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a conceptual diagram of a conventional system. [Diagram 2] FIG. 1 is a schematic diagram of a first embodiment of a furnace system according to the present invention. [Diagram 3] 1 is an example of an apparatus according to the present invention in which a molten steel section and a preheating section are integrated. [Figure 4] FIG. 2 is a schematic diagram of a second embodiment of the furnace system according to the present invention. [Diagram 5] FIG. 2 is a schematic diagram of a third embodiment of a furnace system according to the present invention. [Figure 6] FIG. 2 is a schematic diagram of another embodiment of a furnace system according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of a furnace system 1 according to the present invention will be described below.

[0013] <Terminology> The carbonization section is a part that has the function of burning biomass and the like in a carbonization furnace and carrying out carbonization processing. The molten steel section is a part that has the function of melting scrap iron and the like in an electric furnace and producing steel. The pyrolysis section is a part that has the function of reacting the charcoal obtained in the carbonization section with high-temperature steam (called "superheated steam") in a pyrolysis furnace and pyrolyzing the charcoal into hydrogen, carbon dioxide, and the like. The superheated steam generation section is a part that has the function of steaming water and further raising the temperature to superheated steam that contributes to the above-mentioned pyrolysis.

[0014] <System including conventional carbonization furnace> Fig. 1 is a conceptual diagram of a system including a conventional carbonization furnace. The main components of a system including a conventional carbonization furnace are a drying section 10 that dries biomass, a carbonization section 20 that carbonizes the biomass sent from the drying section 10 by combustion, a pyrolysis section 30 that pyrolyzes the carbonized material sent from the carbonization section 20 with superheated steam, and a superheated steam generation section 40 that generates superheated steam from water and sends it to the pyrolysis section 30.

[0015] In the system according to Fig. 1, the combustion gas in the carbonization section 20 and the like is reused as a heat source. That is, the combustion gas in the carbonization section 20 is sent to the pyrolysis section 30 and used as part of the heat source. In addition, the combustion gas in the pyrolysis section 30 is sent to the superheated steam generation section 40 and used as part of the heat source. In addition, the combustion gas in the superheated steam generation section 40 is sent to the drying section 10 and used as part of the heat source.

[0016] <Technologies used in the furnace system according to the present invention> Fig. 2 is a conceptual diagram of a first embodiment of the furnace system 1 according to the present invention. The pyrolysis section 30 and the superheated steam generation section 40 (both of which are omitted in Fig. 2) according to the present invention may use the devices and methods described in JP 2016-121256 A, JP 2017-132676 A, JP 2017-132969 A, etc., or techniques equivalent thereto.

[0017] Furthermore, the molten steel section 50 according to the present invention may be a general electric furnace or one using technology conforming to JP 2009-46726 A, JP 2011-69606 A, JP 2011-226713 A, JP 2012-37157 A, etc. Furthermore, the heating method of the electric furnace is not limited to a resistance furnace, an arc furnace, an induction furnace, etc.

[0018] In this way, the furnace system 1 of the present invention may be based on the basic technologies of the carbonization furnace, electric furnace, pyrolysis furnace, and superheated steam generation equipment described in the above-mentioned literature, and may be improved, etc., by adding boilers, power generation equipment, oxygen gas generators, belt conveyors, heat exchangers, etc. as necessary so as to have the functions necessary to realize the present invention.

[0019] <Biomass supplied to the furnace system according to the present invention> In the embodiment, the biomass input to the furnace system 1 according to the present invention is wood chips with a size of 50 mm or less derived from construction waste. However, the input to the carbonization section 20 of the present invention is not limited to this, and any material may be input as long as it becomes a carbonized material that can be used in the furnace system 1 by combustion.

[0020] Example 1 A first embodiment of the furnace system 1 according to the present invention will be described with reference to Fig. 2. Note that the moisture content of the biomass, the carbonization temperature, etc. are merely examples of system operation, and the operation of the furnace system 1 according to the present invention is not limited to the ranges shown here. In addition, the furnace system 1 according to the present invention may include devices not shown in the figure.

[0021] First, biomass dried to a moisture content of 15% or less in the drying section 10 (omitted from FIG. 2) is supplied to the carbonization section 20. The carbonization section 20 carbonizes the supplied biomass by combustion. The carbonization is controlled by the residence time and temperature. The carbonization temperature in the carbonization section 20 is 400 to 800°C on average, and preferably 500 to 600°C. In the process of carbonizing the biomass, flammable hydrocarbon gases and the like are generated.

[0022] The carbide produced in the carbonization section 20 is supplied to the molten steel section 50 as a recarburizer, with the amount appropriately adjusted. On the other hand, outside air (air) is supplied to the combustible gas, etc., and combusted up to a predetermined temperature. The combustion temperature of the combustible gas, etc. is 900 to 1300°C. The combustion gas produced by burning the combustible gas is supplied to the preheating section 60 to preheat the raw material (scrap iron) to be supplied to the molten steel section 50.

[0023] The combustion gas may be mixed with outside air (air) to adjust the temperature as necessary, or may be passed through another device (not shown) to adjust the temperature. The combustion gas is supplied to the preheating section 60 and preheats the iron scrap in the preheating section 60. The preheated iron scrap is supplied to the molten steel section 50.

[0024] In Fig. 2, the preheating section 60 and the molten steel section 50 are shown in a separate form, but they may be integrated as shown in Fig. 3 in which the respective functions are included in one device. Also, as shown in Fig. 3, the combustion gas may be supplied to the preheating section (upper region of the device in Fig. 3) via the molten steel section (lower region of the device in Fig. 3). The combustion gas used to preheat the iron scrap may be utilized as heat in a desired part of the furnace system 1, or may be discharged to the atmosphere.

[0025] In the molten steel section 50, the preheated iron scrap is melted in an electric furnace using the carbide from the carbonization section 20 as a recarburizing agent to produce iron. The combustion gas from the molten steel section 50 may be utilized as heat in a desired part of the furnace system 1 or may be released into the atmosphere.

[0026] As described above, the furnace system 1 of the present invention has two paths from the carbonization section 20 to the molten steel section 50: a carbide supply path and a heat supply path via the preheating section 60.

[0027] In addition, the biomass-derived combustion gas according to the present invention contains impurities such as SiO2 and CaO. These are substances that are useful as secondary materials in the molten steel process. In other words, by using the system configuration of the present invention, the heat supply path also serves as a supply path for secondary materials, in which the substances in the combustion gas are trapped in the iron scrap and supplied to the molten steel section 50 together with the iron scrap.

[0028] Example 2 A second embodiment of the furnace system 1 according to the present invention will now be described.

[0029] 4 is a conceptual diagram of a second embodiment of the furnace system 1 according to the present invention. This embodiment differs from the first embodiment of the first embodiment in the presence or absence of a pyrolysis section 30 and in the transport path of the carbide. That is, in the second embodiment, the carbide generated in the carbonization section 20 is supplied to the pyrolysis section 30, and the water gas (described later) generated in the pyrolysis section 30 is supplied to the molten steel section 50. Other than this difference, the basic configuration is the same as that of the first embodiment.

[0030] The carbide supplied to the pyrolysis section 30 reacts (water-gasification reaction, oxidation reaction) with superheated steam (high-temperature water vapor) and oxidant (high-concentration oxygen, oxygen in the air, etc.) supplied from the superheated steam generation section 40 (omitted in FIG. 4). Here, the temperature of the superheated steam generated in the superheated steam generation section 40 is around 800°C, and the water-gasification reaction in the pyrolysis section 30 is 900 to 1200°C. The water-gasification reaction is a reaction in which the carbide (C) reacts with water (H2O) to generate water gas consisting of hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), etc. The water gas is supplied to the molten steel section 50 as an auxiliary fuel.

[0031] New carbides are generated as residues of the water-gasification reaction from the pyrolysis section 30. Although a transport path for the generated carbides is omitted in Fig. 4, the carbides may be supplied to the molten steel section 50 as a recarburizer as necessary.

[0032] In the molten steel section 50, the iron scrap preheated by the electric furnace is melted in the above-mentioned water gas atmosphere to produce iron. The combustion gas in the molten steel section 50 may be utilized as heat in a desired part of the furnace system 1 or may be released to the atmosphere.

[0033] Example 3 A third embodiment of the furnace system 1 according to the present invention will now be described.

[0034] 5 is a conceptual diagram of a third embodiment of the furnace system 1 according to the present invention. It differs from the second embodiment of the second embodiment in the transport path of the char generated in the carbonization section 20. That is, in the third embodiment, the char generated in the carbonization section 20 is supplied to either the pyrolysis section 30 or the melting section 50 as appropriate, or is supplied to both the pyrolysis section and the melting section. The basic configuration other than this difference is the same as that of the second embodiment.

[0035] The transport of the charcoal generated in the carbonization section 20 may be controlled by any means. For example, route control by a belt conveyor that supplies the charcoal, manual route selection, etc. Transporting the charcoal in this manner allows the furnace system 1 to operate according to the purpose.

[0036] Example 4 Another embodiment that the furnace system 1 can take will be described below as a fourth embodiment based on the first to third embodiments.

[0037] Fig. 6 shows an example of the use of heat originating from combustion gas. A specific combustion gas is heat exchanged with water in a boiler 70. The steam generated in this way is supplied to a power generation device 80 and converted into electricity, which drives an oxygen gas generation device (oxygen generation section 90 in Fig. 6) of the PSA type or the like. The oxygen gas generated in the oxygen generation section 90 is supplied to the molten steel section 50 as auxiliary fuel.

[0038] The combustion gas that exchanges heat with the water in the boiler 70 may be the combustion gas from the preheating section 60 or the combustion gas from the molten steel section 50, or may be the combustion gas that is branched and supplied in the path from the carbonization section 20 to the preheating section 60. In this way, the combustion gas from a desired part in the furnace system 1 may be used.

[0039] Also, the combustion gas from the preheating section 60 may be supplied to the drying section 10 (omitted in FIG. 6) for drying the biomass. This forms a heat circulation system including the carbonization section 20 and the preheating section 60 in the furnace system 1, enabling cyclical use of heat. Instead of the combustion gas from the preheating section 60, the combustion gas from the molten steel section 50 may be used to dry the biomass.

[0040] In this manner, a heat circulation path originating from the combustion gas may be constructed between the carbonization section 20 or the molten steel section 50 and a desired part as necessary in the furnace system 1. For example, a heat circulation path including the superheated steam generation section 40 (omitted in FIG. 6) or other devices may be constructed, or a heat circulation path may be constructed via a heat exchange device.

[0041] As described above, the present invention is a furnace system including a carbonization furnace for carbonizing biomass and an electric furnace for molten steel processing of iron scrap, and realizes efficiency as a furnace system. The present invention should not be interpreted based on the name of the device, etc., but should be interpreted flexibly based on the essential functions that constitute the invention. [Industrial Applicability]

[0042] According to the present invention, an efficient furnace system can be constructed by combining a carbonization furnace and an electric furnace. In addition, the thermal energy generated in the furnace system can be combined with devices outside the system or with other systems, enabling further heat utilization. [Explanation of symbols]

[0043] 1. Furnace System 20 Carbonization section 30 Pyrolysis section 50 Molten Steel Section

Claims

1. 1. A furnace system comprising: a carbonization unit that generates carbonized material using biomass as a raw material in a carbonization furnace; A molten steel section that uses scrap iron as raw material to produce steel in an electric furnace; Equipped with supplying carbide produced in the carbonization section to the molten steel section; A furnace system for preheating the iron scrap with heat originating from combustion gases from the carbonization section.

2. 1. A furnace system comprising: a carbonization unit that generates carbonized material using biomass as a raw material in a carbonization furnace; a pyrolysis section for pyrolyzing the carbonized material produced in the carbonization section in a pyrolysis furnace to produce water gas; A molten steel section that uses scrap iron as raw material to produce steel in an electric furnace; Equipped with supplying the water gas produced in the thermal decomposition section to the molten steel section; A furnace system for preheating the iron scrap with heat originating from combustion gases from the carbonization section.

3. 1. A furnace system comprising: a carbonization unit that generates carbonized material using biomass as a raw material in a carbonization furnace; a pyrolysis section for pyrolyzing the carbonized material produced in the carbonization section in a pyrolysis furnace to produce water gas; A molten steel section that uses scrap iron as raw material to produce steel in an electric furnace; Equipped with supplying the carbide produced in the carbonization section to the pyrolysis section and / or the molten steel section as appropriate; When the carbide is supplied to the thermal decomposition section, water gas generated in the thermal decomposition section is supplied to the molten steel section; A furnace system for preheating the iron scrap with heat originating from combustion gases from the carbonization section.

4. The furnace system according to any one of claims 1 to 3, wherein heat originating from combustion gas from the carbonization section and / or the molten steel section is supplied to a desired part in the furnace system.

5. 5. The furnace system according to claim 4, further comprising a heat circulation path for circulating heat originating from the combustion gas within the furnace system.

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