WO2020166659A1 - Method for producing biomass gas, method for producing hydrogen, system for producing biomass gas, and system for producing hydrogen - Google Patents

Abstract

Provided are a method for producing biomass gas and a method for producing hydrogen that include: a pyrolytic gasification step in which a biomass gas is obtained by using biomass as a starting material and performing gasification by water vapor containing a metal component; and a hydrogen production step.

Description

Biomass gas production method, hydrogen production method, biomass gas production system and hydrogen production system

The present invention relates to a biomass gas production method, a hydrogen production method, a biomass gas production system, and a hydrogen production system. The present application claims priority based on Japanese Patent Application No. 2019-26012 filed in Japan on February 15, 2019, the contents of which are incorporated herein by reference.

To date, woody biomass has been used as a combustion fuel or treated as waste. On the other hand, there are various one-stage gasification technologies such as one-stage gasification technology that directly pyrolyzes biomass using high-temperature steam, and two-stage gasification technology that pyrolyzes and decomposes the carbides produced by carbonization of biomass with high-temperature steam. Forms of pyrolysis gasifiers have been developed so far. Biomass gas (mixed gas containing CO, hydrogen, CO ₂ and methane, etc.) generated by pyrolysis gasification is used as electric power in gas engine power generation, and high-purity hydrogen is produced by reforming reaction of biomass gas to produce fuel. It is used for batteries and the like (see Non-Patent Documents 1 to 4).

Pyrolysis gasification of biomass has various forms depending on the method of supplying biomass, the reaction conditions and content such as pressure, temperature and flow rate of oxidizer such as steam, heating method, gasification furnace structure and the like.
As for the pressure, there is a mode in which atmospheric pressure (0.1 to 0.12 MPa) and pressurization (0.2 to 2 MPa) are used to pyrolyze and gasify biomass.
As for the temperature, there is a form in which biomass is pyrolyzed and gasified at low temperature (less than 650° C.) and high temperature (650 to 1200° C.).
As a gasifying agent, there is a type in which air, oxygen, and steam are used to pyrolyze and gasify biomass.
As a heating method, there are an internal combustion gasification in which a part of biomass as a gasification raw material is reacted with oxygen to internally burn, and an external combustion gasification in which biomass as a raw material and steam are externally heated.
Examples of the gasification furnace type include a fixed bed, a fluidized bed, a moving bed, a stirring bed, and a rotary kiln type.
Pyrolysis gasification of biomass is classified according to these types and their combinations.

As a method of using the biomass gas generated by pyrolysis and gasification of biomass, there are gas engine power generation and hydrogen production using steam reforming reaction. In the case of development so far, one-stage pyrolysis gasification method in which high temperature steam is directly used to gasify biomass, and high temperature steam is used to gasify the carbide obtained by carbonizing biomass in a carbonization furnace. A two-stage pyrolysis gasification method is known (see Patent Documents 1 and 2 and Non-Patent Documents 1 to 5).

Japanese Patent Laid-Open No. 2008-88434 Japanese Patent No. 5342264

However, in the conventional technique, the gasification efficiency (heat quantity of biomass gas/(heat quantity of biomass + heat quantity of external heat input)×100) in pyrolysis gasification of biomass is at most 50 to 65%, and improvement and generation of gasification efficiency It is required to increase the amount of gas.
In addition, in the conventional technique, tar, wood vinegar, coke, etc. are secondarily produced in the pyrolysis gasification. It is required to reduce the processing cost of by-products generated as a by-product and reduce the burden on the local environment. It is required to improve the utilization of exhaust heat from the high temperature pyrolysis gasifier. In addition, in a hydrogen production method using biomass gas, there is a demand for energy saving and hydrogen production cost reduction by lowering the reaction process temperature, lowering the pressure, and improving catalyst performance.

The present invention reduces a by-product such as tar in the pyrolysis gasification of biomass and improves the gasification efficiency of biomass and the amount of biomass gas produced, a method for producing hydrogen, a method for producing hydrogen, a system for producing biomass gas, and hydrogen. Intended for manufacturing systems.

The present invention has the following aspects.
[1] A method for producing a biomass gas, which comprises a pyrolysis gasification step of obtaining a biomass gas by using biomass as a raw material and gasifying with steam containing a metal component.
[2] The pyrolysis gasification step includes a combustion operation for burning a part of the biomass, and a gasification operation for obtaining the biomass gas from another part of the biomass and the steam. The biomass gas production method according to [1], wherein the gasification operation uses the exhaust heat generated in the combustion operation as a heat source.
[3] The pyrolysis gasification step has a carbonization operation for carbonizing the biomass to obtain a carbide, and a carbide gasification operation for obtaining the biomass gas from the carbide and the steam. Biomass gas production method.
[4] The method for producing a biomass gas according to any one of [1] to [3], which has a steam heating step of heating the steam by using exhaust heat generated in the pyrolysis gasification step as a heat source. ..
[5] In [1] to [4], the metal component contains at least one element selected from the group consisting of sodium, potassium, lithium, calcium, magnesium, strontium, barium, boron, aluminum and gallium. The method for producing a biomass gas according to any one of claims.
[6] The metal component contains at least one salt selected from the group consisting of carbonates, sulfates, hydrochlorides and silicates, and the content of the salt is 10 to 10000 mg per 1 kg of the steam. The method for producing biomass gas according to any one of [1] to [5].

[7] A biomass gas production step of obtaining the biomass gas by the biomass gas production method according to any one of [1] to [6], and a hydrogen production step of reforming the biomass gas to produce hydrogen. A method for producing hydrogen, comprising:
[8] In the hydrogen production step, a composite reforming catalyst containing at least one metal element selected from iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum and neodymium is used [7 ] The hydrogen production method of description.

[9] A biomass gas production system having a pyrolysis gasification apparatus that obtains biomass gas by gasifying biomass with steam as a raw material and steam containing metal components.
[10] The pyrolysis gasification apparatus has a combustion furnace that burns a part of the biomass, and a gasification furnace that obtains the biomass gas from another part of the biomass and the steam, The biomass gas production system according to [9], wherein the cracking gasifier has means for supplying the exhaust heat generated in the combustion furnace to the gasification furnace.
[11] The pyrolysis gasifier has a carbonization furnace for carbonizing the biomass to obtain a carbide, and a carbide gasification furnace for obtaining the biomass gas from the carbide and the steam. Biomass gas production system.
[12] The biomass gas production system according to any one of [9] to [11], which has steam heating means for heating the steam by using exhaust heat generated in the pyrolysis gasification device as a heat source. ..

[13] A hydrogen production system comprising: the biomass gas production system according to any one of [9] to [12]; and a hydrogen production device that reforms the biomass gas to produce hydrogen.
[14] The hydrogen production device has a reaction bed filled with a composite reforming catalyst, and the composite reforming catalyst includes iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum and The hydrogen production system according to [13], which contains at least one metal element selected from neodymium.

According to the biomass gas production method, hydrogen production method, biomass gas production system and hydrogen production system of the present invention, byproducts such as tar in the pyrolysis gasification of biomass are reduced, and the gasification efficiency of biomass and the production of biomass gas are reduced. The quantity can be improved.

It is a schematic diagram of a hydrogen production system concerning a first embodiment of the present invention. It is a flowchart of the hydrogen production method which concerns on 1st embodiment of this invention. It is a schematic diagram of a hydrogen production system concerning a second embodiment of the present invention. It is a flowchart of the hydrogen production method which concerns on 2nd embodiment of this invention.

The present invention is a method for producing a biomass gas, which is characterized in that biomass is pyrolyzed and gasified using high calorific value steam containing a metal component such as geothermal steam. By the technique shown in the present embodiment, the gasification efficiency of biomass and the amount of biomass gas produced can be improved, and in addition, by-products such as tar can be removed without limit. The exhaust heat of the pyrolysis gasifier and the exhaust heat of the combustion furnace can be improved by using steam heat exchanging means for geothermal power generation (including binary power generation). This makes it possible to provide a method for producing a biomass gas and a method for producing hydrogen, which are excellent in terms of environment and economy.

In the present invention, as the biomass used as a raw material, it is preferable to use pulverized and dried biomass produced or discarded in forestry or agriculture. Examples of biomass include deforested materials such as cedar, pine and bamboo, agricultural products and by-products such as rice straw and sugar cane, industrial waste materials such as construction waste materials, cotton and textile products.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of a hydrogen production system according to this embodiment.

The hydrogen production system 100 of FIG. 1 includes a biomass gas production system 60 and a hydrogen production device 16. The biomass gas production system 60 includes a combustion furnace 9, a pyrolysis gasification device 50 (also referred to as “pyrolysis gasification furnace”), and a steam separator 32.
The combustion furnace 9 is connected to an air blower 30 and a pyrolysis gasification device 50. The steam separator 32 is connected to the geothermal water reservoir 31 and the pyrolysis gasification device 50. The pyrolysis gasification device 50 is connected to the heat exchanger 18 via the gas separation/purification processing unit 13. The heat exchanger 18 is connected to the turbine generator 19, the gas holder 14, and the heat exchanger 17. The gas holder 14 is connected to the gas engine power generator 15. The heat exchanger 17 is connected to the steam separator 32.
In the present embodiment, the pyrolysis gasification device 50 includes a gasification furnace main body 1, a gasification furnace heating unit 8, a gasification reaction tower 10, and a steam heat exchanger 34. The gasification furnace main body 1 is connected to the gasification furnace heating unit 8, the gasification reaction tower 10, and the steam heat exchanger 34.
The steam heat exchanger 34 functions as steam heating means.

The gasification furnace main body 1 has a steam inlet 5 for supplying steam 33 containing a metal component such as geothermal steam into the furnace.
The gasification furnace heating unit 8 is connected to the biomass charging unit 4 that supplies the biomass 3 for pyrolysis gasification from the furnace top to the inside of the furnace.
At the lower part of the gasification reaction tower 10, a discharge part 11 for taking out solid ash and coke produced by pyrolysis gasification is provided. Above the gasification reaction tower 10, a discharge part 12 for the produced biomass gas 2 is provided.

Next, an example of a hydrogen production method using the hydrogen production system 100 will be described with reference to FIGS. 1 and 2.
As shown in FIG. 2, the hydrogen production method according to the present embodiment uses biomass as a raw material, a biomass gas production step P3 for obtaining a biomass gas by gasification with steam containing a metal component, and reforming the biomass gas. And a hydrogen production process P4 for producing hydrogen.

First, the biomass 6 for fuel is charged into the combustion furnace 9 through the upper opening of the combustion furnace 9, and while supplying air into the combustion furnace 9 with the air blower 30, a part of the biomass 6 is burned to generate combustion gas. 7 is generated (combustion operation S1).
The combustion gas 7 generated in the combustion furnace 9 is supplied to the gasification furnace heating unit 8 of the pyrolysis gasification device 50.

Next, the biomass 3 for pyrolysis and gasification is introduced into the gasification furnace main body 1 from the biomass introduction part 4 of the pyrolysis and gasification device 50.

In the present embodiment, as the steam 33 containing a metal component, the geothermal steam obtained by separating the geothermal water pumped from the geothermal water reservoir 31 into a gas by the steam separator 32 is used.
The metal component contained in the water vapor 33 includes at least one element selected from the group consisting of sodium, potassium, lithium, calcium, magnesium, strontium, barium, boron, aluminum and gallium.
The metal component contained in the water vapor 33 may include at least one salt selected from the group consisting of carbonates, sulfates, hydrochlorides and silicates.
The content of the salt is preferably 10 to 10000 mg, more preferably 20 to 1000 mg, relative to 1 kg of steam.

The steam 33 is heated in the steam heat exchanger 34 using the exhaust heat WH generated in the combustion operation S1 as a heat source (steam heating step P2). The steam 33 is introduced into the gasification furnace main body 1 from the steam injection unit 5 below the gasification furnace main body 1. As the steam 33, steam obtained directly from tap water or industrial water after soft water treatment or from heavy oil combustion boiler treatment can be similarly used.
In the gasification furnace main body 1, the charged biomass 3 and the high-temperature steam 33 are mixed and convected and uniformly heated to obtain the biomass gas 2 (gasification operation S2).
Since the steam 33 contains a metal component, the biomass gas 2 with reduced by-products such as tar can be obtained.

The steam 33 supplied into the gasification furnace main body 1 is heated in a high temperature range of 650 to 1200° C., preferably 800 to 1000° C., and supplied to the gasification operation S2. The biomass gas obtained in the gasification operation S2 is supplied to the gasification furnace reaction tower 10. In the interior of the gasification furnace reaction tower 10, is promoted pyrolysis gasification with steam 33 at a high temperature _region, the biomass gas 2 containing CH _4, C 2 hydrocarbons and _H 2 of the _{H 4} and the like, CO, CO ₂ Are produced (pyrolysis gasification step P1).

In the pyrolysis gasification step P1, generally, biomass (C _n H ₂ O _m : C _1.42 H ₂ O _{0.91 in} the case of cedar, bamboo and grass wood, n and m are positive numbers) is used as a raw material. Using steam (H ₂ O) as a gasifying agent, the pyrolysis gasification reaction represented by the following formulas (1), (2), and (3) is mainly used depending on the temperature inside the gasification furnace reaction tower 10.
Internal temperature of the gasification reactor reaction tower 10 800° C.:
C _1.42 H ₂ O _0.91 +0.38H ₂ O=0.74H ₂ +0.75CO+0.24CH ₄ +0.24C ₂ H ₄ +0.28CO ₂ ... Formula (1)
Internal temperature of gasification reactor reaction tower 10 900° C.:
C _1.42 H ₂ O _0.91 +0.71H ₂ O=1.27H ₂ +0.76CO+0.21CH ₄ +0.02C ₂ H ₄ +0.41CO ₂ ... Formula (2)
Internal temperature of the gasification reactor reaction tower 10 1000° C.:
C _1.42 H ₂ O _0.91 +0.89H ₂ O=1.59H ₂ +0.76CO+0.15CH ₄ +0.51CO ₂ ... Formula (3)

In order to produce hydrogen using the produced biomass gas, it is necessary to adjust the pyrolysis gasification step P1 so that the reactions of the above formulas (1), (2) and (3) are smoothly performed. .. When oxygen and air are mixed in the water vapor, the gas heat quantity of the biomass gas decreases due to complete combustion of the biomass, so the water vapor may be deoxygenated.

One of the means for adjusting the pyrolysis gasification step P1 is to control the internal temperature of the gasification furnace reaction tower 10 to 800 to 1000°C. The temperature inside the gasification furnace reaction tower 10 is controlled by controlling the temperature and flow rate of the combustion gas 7 and adjusting the supply flow rates of the biomass 3 and the steam 33 supplied to the gasification furnace main body 1. By controlling the temperature inside the gasification reactor reaction tower 10 at 800 to 1000° C., the pyrolysis gasification reactions (1) to (3) of the biomass 3 proceed at a preferable gasification conversion rate and the biomass gas 2 Is obtained (the above is the biomass gas production process P3).

The solid ash and dust such as coke contained in the biomass gas 2 are removed by the gas separation/purification processing unit 13 that includes a cyclone and a bag filter that physically removes tar generated as a by-product. The biomass gas 2 is stored in the gas holder 14 via the gas separation/purification processing unit 13. The biomass gas 2 is supplied to both or either of the gas engine power generation device 15 and the hydrogen production device 16.

In the present embodiment, the biomass input part 4 is provided at the top of the furnace, and the steam input part 5 is provided at the bottom of the gasification furnace main body 1. However, the present invention is not limited to this, and the biomass 3 may be supplied from below or from the side of the gasification furnace main body 1. The steam 33 may be supplied from the furnace top or the side of the gasification furnace body 1. The supply place of biomass and steam is not limited to one place, but may be plural places.

In the present embodiment, the exhaust heat WH of the combustion gas 7 generated in the combustion operation S1 is supplied to the heat exchanger 17. Exhaust heat WH of the biomass gas 2 generated in the pyrolysis gasification step P1 is supplied to the heat exchanger 18. The exhaust heat WH supplied to the heat exchanger 17 or the heat exchanger 18 is used as an additional heat source of geothermal steam (steam heating step P2). The steam after the heat exchange treatment is supplied to the turbine generator 19 to be used for steam power generation using the exhaust heat.

When hydrogen H is produced using the biomass gas 2, the biomass gas 2 is reformed to produce hydrogen H in the hydrogen production apparatus 16 having the reaction bed filled with the composite reforming catalyst (hydrogen production step. P4). The hydrogen production device 16 may include a booster that pressurizes the gas pressure to a predetermined pressure, and a gas-liquid separation device that separates the generated hydrogen H. Examples of the predetermined pressure include 1 to 20 atmospheric pressure (0.1 to 2 MPa). As the heat source of the hydrogen production device 16, it is also possible to produce hydrogen in a predetermined temperature range by using the exhaust heat of the combustion gas 7 exhausted from the heat exchanger 17. Examples of the predetermined temperature range include 250° C. to 600° C.

In the hydrogen production step P4 of the present embodiment, a composite reforming catalyst containing at least one metal element selected from iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum and neodymium is used. Good. In the present specification, the "composite reforming catalyst" is a conventional catalyst containing nickel, ruthenium or the like as a main component, and selected from iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum and neodymium. The catalyst is a mixture of at least one metal element. These catalysts may be porous oxides containing the above metal elements. The porous oxide is a metal oxide having a large number of fine pores. Examples of the porous oxide include zirconia and the like. The composite reforming catalyst can be prepared according to a conventional impregnation method using an acetone solution of an acetylacetonato complex of a substance containing the above metal element or an aqueous solution of various salts (nitrate, hydrochloride, etc.). Usually, the prepared catalyst is subjected to a reduction treatment using hydrogen gas or a reducing reagent and then subjected to a reforming reaction of biomass gas. However, in the present invention, the composite reforming catalyst may be subjected to the reforming reaction of the biomass gas without performing the reduction treatment using hydrogen gas or a reducing reagent.

In the hydrogen production process P4 of this embodiment, hydrogen is produced by the reforming reaction of the biomass gas 2. In the reforming reaction of the biomass gas 2, the reaction temperature is preferably 250° C. to 600° C., more preferably 350° C. to 450° C. from the viewpoint of reactivity and thermal efficiency. The reaction pressure is preferably 1 to 20 atm (0.1 to 2 MPa), more preferably 5 to 10 atm (0.5 to 1 MPa).

In the present embodiment, the generated hydrogen H is gas-purified by a PSA (Pressure Swing Adsorption) gas separator to obtain high-purity hydrogen (purity of 99.999% or more). High-purity hydrogen is used for fuel cells of fuel cell vehicles, home power generation, and fuel cells for uninterruptible power supply (UPS).

[Second embodiment]
The second embodiment of the present invention will be described with reference to FIG.
FIG. 3 shows a schematic diagram of the hydrogen production system according to the second embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The hydrogen production system 200 of FIG. 3 has a biomass gas production system 62 and a hydrogen production apparatus 16. The biomass gas production system 62 includes a carbonization furnace 21, a carbide gasification furnace 24, and a steam heat exchanger 27.
The carbonization furnace 21 is connected to an air blower 30 and a gasification furnace heating unit 25 provided in the carbide gasification furnace 24. The steam heat exchanger 27 is connected to the gasification furnace heating unit 25, the steam injection unit 26 of the carbide gasification furnace 24, and a supply source of steam 29. The carbide gasification furnace 24 is connected to the heat exchanger 18 via the gas separation/purification processing unit 13. The heat exchanger 18 is connected to the turbine generator 19, the gas holder 14, and the heat exchanger 17. The gas holder 14 is connected to the gas engine power generator 15. The heat exchanger 17 is connected to the steam heat exchanger 27.
In the present embodiment, the pyrolysis gasification device 52 includes a carbonization furnace 21 and a carbide gasification furnace 24.
The steam heat exchanger 27 functions as steam heating means.

Next, an example of a hydrogen production method using the hydrogen production system 200 will be described with reference to FIGS. 3 and 4.
As shown in FIG. 4, the hydrogen production method of the present embodiment has a biomass gas production step including a carbonization operation S3 for carbonizing biomass to obtain a carbide and a carbide gasification operation S4 for obtaining a biomass gas from the carbide and steam. P3 and the hydrogen production process P4 which reforms biomass gas and produces|generates hydrogen.

First, wood biomass 20, such as cedar, pine, and bamboo, is put into the carbonization furnace 21 through the upper opening of the carbonization furnace 21, and the air blower 30 supplies air into the carbonization furnace 21 while partially burning the wood biomass 20. To generate the carbide 22 (carbonization operation S3).
The carbide 22 generated in the carbonization furnace 21 is taken out from the lower end of the carbonization furnace 21, crushed, and then charged into the carbide gasification furnace 24 through the upper opening or the middle opening.
The combustion gas 23 generated in the carbonization furnace 21 is supplied to the gasification furnace heating unit 25 through the upper opening, and heats the inner wall of the carbide gasification furnace 24 to a predetermined temperature. The combustion gas 23 is supplied to the steam heat exchanger 27 via the gasification furnace heating unit 25.

The water vapor 29 contains a metal component.
Examples of the metal component contained in the water vapor 29 include at least one element selected from the group consisting of sodium, potassium, lithium, calcium, magnesium, strontium, barium, boron, aluminum and gallium.
The metal component contained in the water vapor 29 may include at least one salt selected from the group consisting of carbonates, sulfates, hydrochlorides and silicates.
The content of the salt is preferably 10 to 10000 mg, more preferably 20 to 1000 mg, relative to 1 kg of steam.

The steam 29 is heated to a predetermined temperature by the steam heat exchanger 27, and then a part of the steam 29 is supplied from the steam charging unit 26 into the carbide gasification furnace 24. Examples of the predetermined temperature include 650 to 1200°C.
In the carbide gasification furnace 24, a thermal decomposition gasification reaction (C+H ₂ O=CO+H ₂ ) and a CO shift reaction (CO+H ₂ O=CO ₂ +H ₂ ) between the steam 29 and the carbide 22 continuously proceed. (Pyrolysis gasification step P1). As a result, the biomass gas 28, which is a mixed gas of hydrogen (H ₂ ), carbon monoxide (CO), methane (CH ₄ ) and carbon dioxide (CO ₂ ) is generated (carbide gasification operation S4). The generated biomass gas 28 is supplied to the gas separation/purification processing unit 13 (the above is the biomass gas manufacturing process P3).
Since the water vapor 29 contains a metal component, the biomass gas 28 with reduced by-products such as tar can be obtained.
The biomass gas 28 that has passed through the gas separation/purification processing unit 13 is supplied to the heat exchanger 18.

A part of the steam 29 heated by the steam heat exchanger 27 is supplied to the turbine generator 19 via the heat exchangers 17 and 18.

Exhaust heat WH of the combustion gas 23 discharged from the steam heat exchanger 27 is supplied to the heat exchanger 17. Exhaust heat WH of the biomass gas 28 generated in the carbide gasification furnace 24 is supplied to the heat exchanger 18. The exhaust heat WH supplied to the heat exchanger 17 or the heat exchanger 18 is used as an additional heat source for steam such as geothermal steam in the heat exchangers 17 and 18 (steam heating step P2) as in the first embodiment. ). The steam after the heat exchange treatment is supplied to the turbine generator 19 to be used for steam power generation using the exhaust heat.

The biomass gas 28 generated in the carbide gasification furnace 24 of the present embodiment has the tar and coke separated in the gas separation/purification processing unit 13 as in the first embodiment, and the heat exchangers 18, 17 after the purification processing. Are sequentially stored in the gas holder 14.
The biomass gas 28 in the gas holder 14 is supplied to the gas engine power generation device 15 or the hydrogen production device 16 and used for gas power generation and hydrogen production.

In the present embodiment, as in the first embodiment, the produced biomass gas 28 is brought into contact with the composite reforming catalyst, so that the pressure is low (for example, 1 MPa or less) and in a low temperature range (for example, less than 650° C.). It is possible to perform hydrogen production in () (hydrogen production process P4). It is also possible to use the exhaust heat of the combustion gas 23 and the biomass gas 28 discharged from the carbonization furnace 21 and the carbide gasification furnace 24 as the heating heat source of the hydrogen production apparatus 16 to perform hydrogen production in a predetermined temperature range.

Examples of the present invention will be shown below, but the following examples merely illustrate the invention, and the content of the present invention is not limited by the following examples.

[Example 1, Comparative Example 1]
As the steam containing metal components, the geothermal steam obtained by the steam separator of the geothermal water pumped from the geothermal water storage layer was used as the steam for the pyrolysis gasification of biomass. Pyrolysis gasification experiment of biomass by pouring cedar pellets (15% water content) as biomass into the pyrolysis gasification furnace and combustion gas furnace at supply rates of 100 kg/h for gasification and 50 kg/h for combustion, respectively I went. The temperature of the pyrolysis gasification furnace was 900° C., and the pressure was 1.2 atm (0.12 MPa). The weight ratio (S/C [kg]/[kg]) of steam (steam) and biomass in the pyrolysis gasification furnace was set to 1.9. Geothermal steam A (150° C., 0.3 MPa, flow rate 200 kg/h, calorific value 650 kcal/kg) was used as water vapor containing a metal component (Example 1) and soft water treated tap water was used (Comparative Example). Table 1 compares the gasification conversion efficiency of biomass in the pyrolysis gas furnace in 1) and the amount of biomass gas produced, and the test results of the pyrolysis gasification reaction. In the table, “fuel gas yield (m ³ /kg)” means the production amount (Nm ³ ) of fuel gas (H ₂ +CO+CH ₄ +C ₂ H ₆ +CO ₂ ) per 1 kg of biomass. In the table, “C _n H _m (vol %)” means the volume% of the volatile long chain hydrocarbon component in which n (n and m are natural numbers) is 2 or more. The concentrations of CO, hydrogen, CO ₂ , CH ₄ and other hydrocarbons in the outlet gas are determined by FID (hydrogen flame ionization detection) with a micro gas chromatographic analyzer (GL Science Co., Ltd.) which is filled with a gas chroma pack (Gaskuropack) and a molecular sieve 13X. Instrument) Gas chromatographic analyzer (manufactured by Shimadzu Corporation) was used for measurement. The flow rate of the exhaust gas was measured by a wet gas flow meter. The production rate of the produced gas was calculated from the GC (gas chromatography) analysis of the outflow gas. The gasification conversion rate was calculated from the formula “(total lower heating value of biomass gas)/(lower heating value of input biomass)×100”. The biomass gas generation rate was an average value for 2 to 10 hours. The amount of tar and char produced was determined by measuring the weight of the collected filter after stopping the supply of biomass. The metal components contained in the geothermal steam A were Na: 600 mg/kg, K: 95 mg/kg, Mg: 35 mg/kg, Ca: 65 mg/kg, and Sr: 15 mg/kg. The metal component contained in the geothermal steam A was measured by the ion chromatography method. The metal component and the salt component in the steam using the tap water after the soft water treatment are the concentrations per kg of steam, Na: 8 mg/kg, K: 3 mg/kg, Ca: 6 mg/kg, Mg: 3 mg/kg, Al. : 0.2 mg/kg, B: 0.5 mg/kg. The metal component and salt component in the steam using the tap water after the soft water treatment were measured by the ion chromatograph method and the ICP (inductively coupled plasma) emission spectroscopy. From these results, the gasification conversion rate, the amount of fuel gas (biomass gas) generated, and the gas calorific value (lower gas calorific value) compared to the case of using tap water in a biomass gasification furnace that uses geothermal steam containing metal components ) Was significantly improved, and tar generated as a by-product was reduced.

[Examples 2 to 3]
In the same manner as in Example 1, the pyrolysis gasification reaction of biomass was performed using the high temperature steams B and C containing the metal component. The temperature of the pyrolysis gasification furnace was 1000° C., and the pressure was 1 atm (0.1 MPa). The molar ratio (S/C) of steam (steam) and carbon in the pyrolysis gasification furnace was set to 1.5. Steam B (Example 2: 165° C., 0.35 MPa, flow rate 210 kg/h, heat amount 650 kcal/kg) and steam C (Example 3: 180° C., 0.5 MPa, flow rate 200 kg/h, heat amount 670 kcal/kg) Table 2 shows the gas component composition of the fuel gas, the gasification conversion rate, the fuel gas yield, etc. From these results, when steam B and C containing a metal component were used in the pyrolysis gasification, the gasification conversion rate, the fuel gas yield and the gas calorific value (lower gas calorific value) were the same as those in Comparative Example 1 using water. It was proved to increase compared with the above. The amount of tar produced was significantly reduced. The metal component of the steam B was Na: 650 mg/kg, Li: 150 mg/kg, Ca: 20 mg/kg, B: 120 mg/kg, Mg: 230 mg/kg in terms of concentration per kg of steam. On the other hand, the concentration of the metal component of the water vapor C was Na: 380 mg/kg, K: 120 mg/kg, Mg: 85 mg/kg, Al: 130 mg/kg, Ba: 78 mg/kg per 1 kg of water vapor. The metal component contained in the water vapor B was measured by the same method as the metal component and the salt component in the water vapor using the tap water after the soft water treatment. The metal component contained in the steam C was measured by the same method as the metal component contained in the geothermal steam A.

[Examples 4 to 5, Comparative Example 2]
Composite reforming catalyst A (8%Ni, 10%Ru, 1%Pt, 5%Ce, 1%Ti, 2%Co/Al ₂ O ₃ ) or composite reforming catalyst B (2%Fe, 10%) Biomass gas obtained by pyrolysis gasification of Example 1 in a steam reforming reactor filled with Ru, 1% Rh, 5% Zr, 2% Mo, 2% La/Al ₂ O ₃ ) (wt %) The reforming reaction was carried out using (45% H ₂ , 8% CH ₄ , 25% CO, 21% CO ₂ , 1% C ₂ H ₆ ) (Examples 4 and 5). The exit biomass gas of the pyrolysis gasification furnace was introduced into the steam reforming reactor after water washing treatment and gas purification. The reaction conditions were reaction temperature: 250° C. and pressure: 0.5 MPa. Table 3 shows the hydrogen production test results when a steam reforming reactor for biomass gas obtained by biomass pyrolysis gasification was provided. In the table, “hydrogen yield (Nm ³ /h)” represents the amount of hydrogen having a purity of 99.999% or more. As shown in Table 3, the yields of hydrogen after the gas-liquid separation of the produced hydrogen gas and the PSA gas purification treatment were 690 Nm ³ /h (Example 4) and 645 Nm ³ /h (Example 5). Compared to the case of using the commercially available catalyst (25% Ni, 5% Ru/Al ₂ O ₃ ) shown in Comparative Example 2 (540 Nm ³ /h), the catalyst A of Example 4 and the catalyst of Example 5 were compared. It was demonstrated that the hydrogen yield and hydrogen conversion rate with B were increased.

[Experimental Example 1]
In Example 1, the combustion gas (1000 to 1200° C.) and the biomass gas (650 to 800° C.) discharged from the pyrolysis gasification furnace using cedar pellets are connected to the gasification furnace outlet and the furnace heating part, respectively. In the heat exchanger, additional heating of geothermal steam for steam power generation (flow rate 2 t/h) was performed. Under the same operating conditions as in Example 1, steam turbo power generation was performed using high calorific steam obtained by utilizing exhaust heat of combustion gas and biomass gas of a pyrolysis gasification furnace (Experimental Example 1). As a result, the power generation efficiencies with and without the use of the exhaust heat of the pyrolysis gasification furnace were 16% and 15%, and the power transmission end outputs were 273kWe and 213kWe. It was found that the use of waste heat from the biomass gasifier increases the geothermal power output by 30%.

[Example 6, Comparative Example 3]
Using construction waste material pellets (15% water content) as biomass, it was charged into the high-temperature carbonization furnace shown in FIG. 3 at a supply rate of 150 kg/h to generate 45 kg/h of carbide at a carbide recovery rate of 35%. Carbide obtained by mechanically crushing the recovered carbide was charged from the upper part of the pyrolysis gasification furnace. Water vapor D containing a metal component (Example 6: 150° C., 0.35 MPa, flow rate 200 kg/h, calorific value 658 kcal/kg) was charged into the pyrolysis gasification furnace and tap water was used (Comparative Example 3). Table 4 shows the test results of the pyrolysis gasification reaction with respect to the gasification conversion rate, the amount of produced gas, and the gas composition of the above-mentioned carbides. The temperature of the pyrolysis gasification furnace was 950° C., and the pressure was 1.2 atm (0.12 MPa). The molar ratio (S/C) of steam (steam) and carbide in the pyrolysis gasification furnace was 1.2. From these results, the gasification conversion rate, the fuel gas yield and the lower gas calorific value in the case of using the steam containing the metal component in the two-stage pyrolysis gasification furnace of biomass are higher than those of Comparative Example 3 using tap water. It was proved that it increased. The H ₂ /CO molar ratio of the produced gas was 4.3 when steam D was used, and the hydrogen produced molar ratio was increased compared to 2.5 when tap water was used. In addition, the gasification and conversion efficiency of biomass was improved to 68%. The concentration of the metal component contained in the water vapor D was Na: 600 mg/kg, Li: 80 mg/kg, Sr: 15 mg/kg, Ga: 20 mg/kg, B: 12 mg/kg per 1 kg of water vapor. The concentration of the metal component contained in the water vapor D was measured by the same method as the metal component and the salt component in the water vapor using the tap water after the soft water treatment. The concentrations of metal components in the tap water used were Na: 6 mg/kg, K: 2 mg/kg, Ca: 5 mg/kg, Mg: 2 mg/kg, and Al: 0.1 mg/kg per 1 kg of steam. The concentration of metal components in tap water was measured by the same method as the metal components contained in geothermal steam A.

According to the present invention, it was found that the gasification efficiency of biomass and the yield of fuel gas and hydrogen can be improved by utilizing steam containing metal components such as geothermal steam in the pyrolysis gasification of biomass such as wood and agricultural waste. It was As a result, it is possible to provide a method for reducing the environmental load and an economical biomass pyrolysis gasification and hydrogen production method.

According to the present invention, by-products such as tar in the pyrolysis gasification of biomass can be reduced and the gasification efficiency of biomass and the amount of biomass gas produced can be improved.

1 Gasification furnace main body 2 Pyrolysis gas (biomass gas)
3 Biomass for pyrolysis gasification 4 Biomass input part 5 Steam input part 6 Biomass for fuel 7 Combustion gas 8 Gasification furnace heating part 9 Combustion furnace 10 Gasification reaction tower 11 Discharge part 12 Biomass gas discharge part 13 Gas separation Refining processing unit 14 Gas holder 15 Gas engine power generation device 16 Hydrogen production device 17 Heat exchanger 18 Heat exchanger 19 Turbine generator 20 Wood biomass 21 Carbonization furnace 22 Carbide 23 Combustion gas 24 Carbide gasification furnace 25 Gasification furnace heating part 26 Steam input unit 27 Steam heat exchanger 28 Biomass gas 29 Steam 30 Air blower 31 Geothermal water reservoir 32 Steam separator 33 Steam 34 Steam heat exchanger 50 Pyrolysis gasifier 52 Pyrolysis gasifier 60 Biomass gas production System 62 Biomass gas production system 100 Hydrogen production system 200 Hydrogen production system P1 Pyrolysis gasification process P2 Steam heating process P3 Biomass gas production process P4 Hydrogen production process S1 Combustion operation S2 Gasification operation S3 Carbonization operation S4 Carbide gasification operation WH Emission heat

Claims (14)

1. A method for producing biomass gas, which has a pyrolysis gasification process in which biomass gas is gasified by steam containing metal components to obtain biomass gas.
2. The pyrolysis gasification step has a combustion operation of burning a part of the biomass, a gasification operation of obtaining the biomass gas from the other part of the biomass and the steam,
   The biomass gas production method according to claim 1, wherein in the gasification operation, exhaust heat generated in the combustion operation is used as a heat source.
3. The biomass gas production according to claim 1, wherein the pyrolysis gasification step includes a carbonization operation for carbonizing the biomass to obtain a carbide and a carbide gasification operation for obtaining the biomass gas from the carbide and the steam. Method.
4. The method for producing a biomass gas according to any one of claims 1 to 3, further comprising a steam heating step of heating the steam by using exhaust heat generated in the pyrolysis gasification step as a heat source.
5. 5. The metal component according to claim 1, wherein the metal component contains at least one element selected from the group consisting of sodium, potassium, lithium, calcium, magnesium, strontium, barium, boron, aluminum and gallium. The method for producing a biomass gas described.
6. The metal component includes at least one salt selected from the group consisting of carbonates, sulfates, hydrochlorides and silicates, and the content of the salt is 10 to 10000 mg with respect to 1 kg of the steam. Item 6. The method for producing a biomass gas according to any one of Items 1 to 5.
7. A biomass gas production step of obtaining the biomass gas by the method for producing biomass gas according to any one of claims 1 to 6,
   A hydrogen production step of reforming the biomass gas to produce hydrogen.
8. The said hydrogen production process uses the composite reforming catalyst containing at least 1 sort(s) of metal element selected from iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum, and neodymium. Hydrogen production method.
9. A biomass gas production system that has a pyrolysis gasifier that uses biomass as a raw material to produce biomass gas by gasification with steam containing metal components.
10. The pyrolysis gasifier has a combustion furnace that burns a part of the biomass, and a gasification furnace that obtains the biomass gas from the other part of the biomass and the steam,
    The biomass gas production system according to claim 9, wherein the pyrolysis gasification device has means for supplying the exhaust heat generated in the combustion furnace to the gasification furnace.
11. The biomass gas production according to claim 9, wherein the pyrolysis gasifier has a carbonization furnace that carbonizes the biomass to obtain a carbide, and a carbide gasification furnace that obtains the biomass gas from the carbide and the steam. system.
12. The biomass gas production system according to any one of claims 9 to 11, further comprising steam heating means for heating the steam by using exhaust heat generated by the pyrolysis gasification device as a heat source.
13. A biomass gas production system according to any one of claims 9 to 12,
    A hydrogen production system comprising: a hydrogen production apparatus that reforms the biomass gas to produce hydrogen.
14. The hydrogen generator has a reaction bed filled with a composite reforming catalyst,
    The hydrogen production system according to claim 13, wherein the composite reforming catalyst contains at least one metal element selected from iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum and neodymium.

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