JPWO2020166659A1 - Biomass gas production method, hydrogen production method, biomass gas production system and hydrogen production system - Google Patents

Abstract

A biomass gas production method and a hydrogen production method, which comprises a pyrolysis gasification step and a hydrogen production step of obtaining biomass gas by gasification with steam containing a metal component using biomass as a raw material.

Description

The present invention relates to a biomass gas production method, a hydrogen production method, a biomass gas production system and a hydrogen production system. This 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.

So far, woody biomass has been used as a combustion fuel or treated as waste. On the other hand, there are various technologies such as one-stage gasification technology that directly pyrolyzes and gasifies biomass using high-temperature steam, and two-stage gasification technology that pyrolyzes and gasifies the charcoal produced by the biomass carbonization process with high-temperature steam. A form of pyrolysis gasification furnace has been developed so far. Biomass gas (mixed gas containing CO, hydrogen, CO _2, methane, etc.) generated by thermal decomposition gasification is used for power generation in gas engine power generation, and high-purity hydrogen is produced by the reforming reaction of biomass gas as fuel. It is used for batteries and the like (see Non-Patent Documents 1 to 4).

There are various types of thermal decomposition gasification of biomass depending on the method of supplying biomass, reaction conditions and contents such as pressure, temperature and flow rate of oxidant such as steam, heating method, gasification furnace structure and the like.
As the pressure, there is a type in which biomass is pyrolyzed and gasified by normal pressure (0.1 to 0.12 MPa) and pressurization (0.2 to 2 MPa).
As the temperature, there is a form in which biomass is pyrolyzed and gasified at a low temperature (less than 650 ° C.) and a high temperature (650 to 1200 ° C.).
As a gasifying agent, there is a form in which biomass is pyrolyzed and gasified using air, oxygen, and steam.
As a heating method, there are an internal combustion type gasification in which a part of biomass as a gasification raw material is reacted with oxygen and internally combusted, and an external combustion type gasification in which the raw material biomass and steam are heated from the outside.
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.

Biomass gas generated by pyrolysis gasification of biomass can be used for gas engine power generation and hydrogen production by applying a steam reforming reaction. In the development cases so far, a one-stage pyrolysis gasification method that directly gasifies biomass using high-temperature steam, and a carbonized product obtained by carbonizing biomass in a carbonization furnace are gasified using high-temperature steam. A two-stage pyrolysis gasification method is known (see Patent Documents 1 and 2 and Non-Patent Documents 1 to 5).

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

Supervised by Masaru Ichikawa "New Development of Biomass Refinery Catalyst Technology" CMC Publishing (2011) pp70-77, pp99-106 D. Xianwen et al., Energy Fuels 14, 2000, 552 I. D. Barn et al., Energy Fuels 14, 2000, 889 Kenichi Sasauchi, Utilization of power generation by pyrolysis gasification of biomass, Journal of Combustion Society of Japan, Vol. 47, No. 139 (2005), pp. 31-39 Masaru Ichikawa, Life and Environment, Vol. 61, No. 1 (2016) "New Development of Hydrogen Energy Technology Utilizing Biomass Resources"

However, in the conventional technique, the gasification efficiency (biomass heat amount / (biomass heat amount + external heat input heat amount) × 100) in the thermal decomposition gasification of biomass is at most 50 to 65%, and the gasification efficiency is improved and generated. There is a need to increase the amount of gas.
In addition, in the conventional technique, tar, wood vinegar, cork and the like are secondarily produced in pyrolysis gasification. It is required to reduce the processing cost of by-products generated as a by-product and the burden on the local environment. There is a need to improve the use of waste heat from high-temperature thermal decomposition gasification furnaces. In addition, in the hydrogen production method using biomass gas, energy saving and reduction of hydrogen production cost by lowering the temperature of the reaction process, lowering the pressure, and improving the catalytic performance are required.

The present invention is a biomass gas production method, a hydrogen production method, a biomass gas production system, and hydrogen that can reduce by-products such as tar in the thermal decomposition gasification of biomass and improve the gasification efficiency of biomass and the amount of biomass gas produced. The purpose is a manufacturing system.

The present invention has the following aspects.
[1] A biomass gas production method comprising a pyrolysis gasification step of obtaining biomass gas by using biomass as a raw material and gasifying with steam containing a metal component.
[2] The thermal decomposition gasification step includes a combustion operation for burning a part of the biomass and a gasification operation for obtaining the biomass gas from the other 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 according to [1], which comprises a carbonization operation of carbonizing the biomass to obtain carbonized material and a carbonization gasification operation of obtaining the biomass gas from the carbonized material and the water vapor. Biomass gas production method.
[4] The biomass gas production method according to any one of [1] to [3], which comprises a steam heating step of heating the steam using the waste heat generated in the pyrolysis gasification step as a heat source. ..
[5] The metal components of [1] to [4], 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 biomass gas production method according to any one of the above.
[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 10,000 mg with respect to 1 kg of the water vapor. The biomass gas production method 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 generate hydrogen. , A hydrogen production method.
[8] The hydrogen production step uses a composite reforming catalyst containing at least one metal element selected from iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum and neodymium [7]. ] The hydrogen production method described in.

[9] A biomass gas production system having a pyrolysis gasification device that uses biomass as a raw material and gasifies it with steam containing a metal component to obtain biomass gas.
[10] The thermal decomposition gasification apparatus 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, and the heat. The biomass gas production system according to [9], wherein the decomposition gasification apparatus has means for supplying the exhaust heat generated in the combustion furnace to the gasification furnace.
[11] The pyrolysis gasification apparatus according to [9], wherein the pyrolysis gasification apparatus includes a carbonization furnace that carbonizes the biomass to obtain carbonized material, and a carbide gasification furnace that obtains the biomass gas from the carbonized material and the water vapor. Biomass gas production system.
[12] The biomass gas production system according to any one of [9] to [11], which has a steam heating means for heating the steam by using the waste heat generated by 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 apparatus for reforming the biomass gas to generate hydrogen.
[14] The hydrogen production apparatus has a reaction bed filled with a composite reforming catalyst, and the composite reforming catalyst includes iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lantern and the like. The hydrogen production system according to [13], which comprises at least one metallic element selected from neodymium.

According to the biomass gas production method, the hydrogen production method, the biomass gas production system and the hydrogen production system of the present invention, by-products such as tar in the pyrolysis gasification of biomass are reduced, and the efficiency of biomass gasification and the generation of biomass gas are achieved. The amount can be improved.

It is a schematic diagram of the hydrogen production system which concerns on 1st Embodiment of this invention. It is a flowchart of the hydrogen production method which concerns on 1st Embodiment of this invention. It is a schematic diagram of the hydrogen production system which concerns on the 2nd Embodiment of this invention. It is a flowchart of the hydrogen production method which concerns on 2nd Embodiment of this invention.

The present invention is a biomass gas production method characterized in that biomass is pyrolyzed and gasified by utilizing high calorific value steam containing a metal component such as geothermal steam. By the technique shown in this embodiment, it is possible to improve the gasification efficiency of biomass and the amount of biomass gas produced, and in addition, it is possible to remove by-products such as tar as much as possible. The exhaust heat of the pyrolysis gasifier and the exhaust heat of the combustion furnace can be improved by using the steam heat exchange means for geothermal power generation (including binary power generation). This makes it possible to provide a biomass gas production method and a hydrogen production method that 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 crushed and dried biomass produced or discarded in forestry or agriculture. Examples of biomass include deforested timber such as cedar, pine and bamboo, agricultural products and by-products such as rice straw and sugar cane, construction waste, and industrial waste such as cotton and textile products.

[First Embodiment]
The 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 the present embodiment.

The hydrogen production system 100 of FIG. 1 includes a biomass gas production system 60 and a hydrogen production apparatus 16. The biomass gas production system 60 includes a combustion furnace 9, a pyrolysis gasification device 50 (also referred to as a “pyrolysis gasification furnace”), and a steam separator 32.
The combustion furnace 9 is connected to the air blower 30 and the pyrolysis gasification device 50. The steam separator 32 is connected to the geothermal water storage layer 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 generation device 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 a gasification furnace heating unit 8, a gasification reaction tower 10, and a steam heat exchanger 34.
The steam heat exchanger 34 functions as a steam heating means.

The gasification furnace main body 1 has a steam input unit 5 that supplies steam 33 containing a metal component such as geothermal steam to the inside of the furnace.
The gasification furnace heating section 8 is connected to a biomass input section 4 that supplies biomass 3 for pyrolysis gasification to the inside of the furnace from the top of the furnace.
At the lower part of the gasification reaction tower 10, a discharge unit 11 for taking out solid ash and cork generated by pyrolysis gasification is provided. At the upper part of the gasification reaction tower 10, a discharge portion 12 of the generated 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, in the hydrogen production method according to the present embodiment, a biomass gas production step P3 for obtaining biomass gas by gasification with steam containing a metal component using biomass as a raw material and reforming the biomass gas are performed. It has a hydrogen production step P4 for producing hydrogen.

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

Next, the biomass 3 for pyrolysis gasification is charged into the gasification furnace main body 1 from the biomass input unit 4 of the pyrolysis gasification device 50.

In the present embodiment, as the steam 33 containing a metal component, the geothermal steam obtained by separating the gas from the geothermal water pumped from the geothermal water reservoir 31 with the gas-water separator 32 is used.
Examples of the metal component contained in the water vapor 33 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 33 may contain at least one salt selected from the group consisting of carbonates, sulfates, hydrochlorides and silicates.
The salt content is preferably 10 to 10000 mg, more preferably 20 to 1000 mg with respect to 1 kg of water vapor.

The steam 33 is heated by using the waste heat WH generated in the combustion operation S1 in the steam heat exchanger 34 as a heat source (steam heating step P2). The steam 33 is charged into the gasifier main body 1 from the steam input unit 5 at the lower part of the gasifier main body 1. As the steam 33, steam obtained by directly treating tap water or industrial water after softening treatment or by treating with a heavy oil combustion boiler can be used in the same manner.
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 water vapor 33 contains a metal component, 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 to preferably 800 to 1000 ° C. in a high temperature range of 650 to 1200 ° C. and is subjected to the gasification operation S2. The biomass gas obtained in the gasification operation S2 is supplied to the gasification furnace reaction tower 10. Inside the gasification furnace reaction tower 10, pyrolysis gasification by steam 33 is promoted in a high temperature range, and hydrocarbons such as _{CH 4} , C ₂ H ₄ and biomass gas 2 containing _{H 2} , CO, and CO _{2 are contained.} Is generated (pyrolysis gasification step P1).

In the pyrolysis gasification step P1, in general, biomass (C _n H ₂ O _{m : C 1.42} H ₂ O _{0.91 for} cedar, bamboo and grass wood, n and m are positive numbers) is used as a raw material. , Steam (H ₂ O) is used as a gasifying agent, and the pyrolysis gasification reactions of the following formulas (1), (2) and (3) are mainly carried out according to the temperature inside the gasification furnace reaction tower 10.
The temperature inside the gasifier reaction tower 10 is 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 ... Equation (1)
Temperature inside the gasifier 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 ... Equation (2)
The temperature inside the gasifier reaction tower 10 is 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 ... Equation (3)

In order to produce hydrogen using the generated biomass gas, it is necessary to adjust the pyrolysis gasification step P1 so that the reactions of the above formulas (1), (2) and (3) can be smoothly carried out. .. When oxygen or air is mixed with water vapor, the gas calorific value of the biomass gas decreases due to the complete combustion of the biomass, so that the water vapor may be deoxidized.

One of the means for adjusting the pyrolysis gasification step P1 is to control the temperature inside the gasification furnace reaction tower 10 to 800 to 1000 ° C. The temperature inside the gasification furnace reaction tower 10 is controlled by adjusting the supply flow rates of the biomass 3 and the steam 33 supplied to the gasification furnace main body 1 in addition to controlling the temperature and the flow rate of the combustion gas 7. By controlling the temperature inside the gasification furnace reaction tower 10 to 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 (The above is the biomass gas production process P3).

Soot dust such as solid ash and cork contained in the biomass gas 2 is removed by a gas separation / purification processing unit 13 including a cyclone and a bag filter for physically removing 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 one of the gas engine power generation device 15 and the hydrogen production device 16.

In the present embodiment, the biomass charging unit 4 is provided at the top of the furnace, and the steam charging unit 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 gasifier main body 1. The steam 33 may be supplied from the top or side of the gasification furnace main body 1. The biomass and steam supply points may be not limited to one place but may be multiple places.

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

When hydrogen H is produced using the biomass gas 2, the biomass gas 2 is modified to generate hydrogen H in the hydrogen production apparatus 16 having a reaction bed filled with a 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 atm (0.1 to 2 MPa). As a heat source of the hydrogen production apparatus 16, hydrogen can be produced in a predetermined temperature range by using the waste heat of the combustion gas 7 discharged 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. May be good. In the present specification, the "composite type reforming catalyst" is selected from iron, cobalt, platinum, rhodium, molybdenum, zirconium, titanium, cerium, lanthanum and neodymium as a conventional catalyst containing nickel, ruthenium and the like as main components. A catalyst in which at least one kind of metal element is mixed. These catalysts may be porous oxides containing the above metal elements. Porous oxides are metal oxides with a large number of fine pores. Examples of the porous oxide include zirconia and the like. The composite reforming catalyst can be prepared by using an acetone solution of the acetylacetonato complex of the above-mentioned metal-containing substance or an aqueous solution of various salts (nitrate, hydrochloride, etc.) according to the conventional impregnation method. Usually, the prepared catalyst is subjected to a reforming reaction of biomass gas after a reduction treatment using hydrogen gas or a reducing reagent. However, in the present invention, the complex reforming catalyst may be subjected to a reforming reaction of biomass gas without performing a reduction treatment using hydrogen gas or a reducing reagent.

In the hydrogen production step P4 of the present embodiment, hydrogen production is performed 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 (hydrogen having a purity of 99.999% or more). High-purity hydrogen is used for fuel cells in fuel cell vehicles, household power generation and 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 view 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 a gasification furnace heating unit 25, a steam input 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 generation device 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 a 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 carbon dioxide and a carbonization gasification operation S4 for obtaining biomass gas from carbon dioxide and water vapor. It has P3 and a hydrogen production step P4 that reforms biomass gas to generate hydrogen.

First, woody biomass 20 such as cedar, pine, and bamboo is put into the carbonization furnace 21 from the upper opening of the carbonization furnace 21, and while air is supplied into the carbonization furnace 21 by an air blower 30, partial combustion of the woody biomass 20 is performed. 22 is produced in (carbonization operation S3).
The carbide 22 produced in the carbonization furnace 21 is taken out from the lower end portion of the carbonization furnace 21, crushed, and then charged into the carbide gasification furnace 24 from 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 carbonization 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 contain at least one salt selected from the group consisting of carbonates, sulfates, hydrochlorides and silicates.
The salt content is preferably 10 to 10000 mg, more preferably 20 to 1000 mg with respect to 1 kg of water vapor.

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 input unit 26 into the carbide gasification furnace 24. Examples of the predetermined temperature include 650 to 1200 ° C.
Inside the carbide gasification furnace 24, a pyrolysis 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 proceed continuously. (Pyrolysis gasification step P1). As a result, _{biomass gas 28, which is a mixed gas of hydrogen (H 2} ), carbon monoxide (CO), methane (CH ₄ ) and carbon dioxide (CO ₂ ), is produced (carbide gasification operation S4). The generated biomass gas 28 is supplied to the gas separation / purification processing unit 13 (above, biomass gas production step P3).
Since the water vapor 29 contains a metal component, a 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.

The waste heat WH of the combustion gas 23 discharged from the steam heat exchanger 27 is supplied to the heat exchanger 17. The waste heat WH of the biomass gas 28 generated in the carbide gasification furnace 24 is supplied to the heat exchanger 18. The waste 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 as in the first embodiment (steam heating step P2). ). The steam after the heat exchange treatment is put into the turbine generator 19 and used for steam power generation using waste heat.

As in the first embodiment, the biomass gas 28 generated in the charcoal gasification furnace 24 of the present embodiment is separated from tar and cork by the gas separation and purification processing unit 13, and after the purification processing, the heat exchangers 18 and 17 are used. Is stored in the gas holder 14 in order.
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, by contacting the generated biomass gas 28 with the composite reforming catalyst, the pressure is low (for example, 1 MPa or less) and the temperature is low (for example, less than 650 ° C.). ), It is possible to produce hydrogen (hydrogen production step P4). As a heating heat source for the hydrogen production apparatus 16, hydrogen can be produced in a predetermined temperature range by using the exhaust heat of the combustion gas 23 and the biomass gas 28 discharged from the carbonization furnace 21 and the carbonized gasification furnace 24.

Examples of the present invention are shown below, but the following examples are merely examples of 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 a metal component, the geothermal steam obtained by the hydrothermal separator pumped from the geothermal water storage layer was used as the steam for pyrolysis gasification of biomass. Pyrolysis gasification experiment of biomass by putting cedar pellets (15% water content) as biomass into pyrolysis gasification furnace and combustion gas furnace at supply speeds of 100 kg / h for gasification and 50 kg / h for combustion, respectively. Was done. 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) to biomass in the pyrolysis gasification furnace was set to 1.9. When geothermal steam A (150 ° C., 0.3 MPa, flow rate 200 kg / h, calorific value 650 kcal / kg) was used as the steam containing a metal component (Example 1) and when tap water treated with soft water was used (comparative example). Table 1 shows the test results of the pyrolysis gasification reaction regarding the gasification conversion efficiency of the biomass of the pyrolysis gas furnace in 1) and the amount of biomass gas produced. In the table, "fuel gas yield (m ³ / kg)" means the amount of fuel gas (H ₂ + CO + CH ₄ + C ₂ H ₆ + CO ₂ ) produced ^{per 1 kg of biomass (Nm 3} ). In the table, "C _n H _m (vol%)" means the volume% of the volatile long-chain hydrocarbon component having n (n, m is a natural number) of 2 or more. The CO, hydrogen, CO ₂ , CH ₄ and other hydrocarbon concentrations in the outlet gas are determined by a micro gas chromatograph (manufactured by GL Sciences Co., Ltd.) and FID (hydrogen flame ionization detection) filled with gas chromatopack and molecular sieve 13X. Instrument) Measurement was performed using a gas chromatograph analyzer (manufactured by Shimadzu Corporation). 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 low calorific value of biomass gas) / (low calorific value of input biomass) x 100". The production rate of biomass gas was an average value of 2 to 10 hours. The amount of tar and char produced was determined by measuring the weight collected by the filter after stopping the biomass supply. 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 an ion chromatograph method. The metal component and salt component in the steam using tap water after soft water treatment are the concentrations per 1 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 water vapor using tap water after the soft water treatment were measured by ion chromatography and ICP (inductively coupled plasma) emission spectroscopy. From this result, compared with the case of using tap water in a gasification furnace of biomass using geothermal steam containing metal components, the gasification conversion rate, the amount of fuel gas (biomass gas) produced, and the amount of gas calorific value (low gas calorific value) ) Was significantly improved, and the amount of tar produced as a by-product was reduced.

[Examples 2 to 3]
Similar to Example 1, the thermal decomposition gasification reaction of biomass was carried out using high temperature steam B and C containing a 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) to carbon in the pyrolysis gasification furnace was 1.5. Steam B (Example 2: 165 ° C., 0.35 MPa, flow rate 210 kg / h, calorific value 650 kcal / kg) and steam C (Example 3: 180 ° C., 0.5 MPa, flow rate 200 kg / h, calorific value 670 kcal / kg). Table 2 shows the gas component composition, gasification conversion rate, fuel gas yield, etc. of the fuel gas when used. From this result, when steam B and C containing a metal component are used in the thermal decomposition gasification, the gasification conversion rate, the yield of the fuel gas and the gas calorific value (low gas calorific value) are shown in Comparative Example 1 using normal water. It was demonstrated that it increased in comparison. The amount of tar produced was significantly reduced. The metal component contained in water vapor B was Na: 650 mg / kg, Li: 150 mg / kg, Ca: 20 mg / kg, B: 120 mg / kg, Mg: 230 mg / kg in the concentration per 1 kg of water vapor. On the other hand, the concentration of the metal component contained in 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 steam B was measured by the same method as the metal component and salt component in steam using tap water after soft water treatment. The metal component contained in water vapor C was measured by the same method as the metal component contained in geothermal water vapor 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 a composite type reforming catalyst B (2% Fe, 10% ru, 1% Rh, 5% Zr, 2% Mo, 2% La / Al 2 O 3) ( wt%) biomass gas obtained by thermal decomposition gasification of example 1 filled steam reforming reactor 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 biomass gas at the outlet of the pyrolysis gasification furnace was charged into the steam reforming reactor after water cleaning treatment and gas purification. The reaction conditions were reaction temperature: 250 ° C. and pressure: 0.5 MPa. Table 3 shows the results of the hydrogen production test when equipped with a steam reforming reactor for biomass gas obtained by biomass pyrolysis gasification. 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 hydrogen yields obtained by performing the PSA gas purification treatment after gas-liquid separation of the produced hydrogen gas were 690 Nm ³ / h (Example 4) and 645 Nm ³ / h (Example 5). Compared with 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 are used. It was demonstrated that the hydrogen yield and hydrogen conversion rate were increased when B was used.

[Experimental Example 1]
In Example 1, the combustion gas (1000 to 1200 ° C.) and the biomass gas (650 to 800 ° C.) discharged in the thermal decomposition gasification furnace using cedar pellets are connected to the gasification furnace outlet and the furnace heating unit, respectively. In the heat exchanger, additional heating of geothermal steam (flow rate 2 t / h) for steam power generation was carried out. Under the same operating conditions as in Example 1, steam turbo power generation was performed using high calorific value steam obtained by utilizing the exhaust heat of the combustion gas and biomass gas of the pyrolysis gasification furnace (Experimental Example 1). As a result, the power generation efficiencies when the waste heat of the pyrolysis gasification furnace was used and when the waste heat was not used 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 gasification furnace increased the geothermal power generation output by 30%.

[Example 6, Comparative Example 3]
Building waste pellets (15% water content) were used as biomass and charged into a high-temperature carbonization furnace shown in FIG. 3 at a supply rate of 150 kg / h to generate 45 kg / h of carbide with a carbonization recovery rate of 35%. The carbide obtained by mechanically crushing the recovered carbide was charged from the upper part of the pyrolysis gasification furnace. When steam D containing a metal component (Example 6: 150 ° C., 0.35 MPa, flow rate 200 kg / h, calorific value 658 kcal / kg) is put into a pyrolysis gasification furnace and when tap water is used (Comparative Example 3). Table 4 shows the test results of the pyrolysis gasification reaction regarding the gasification conversion rate, the amount of produced gas, and the gas composition of the carbonized material. 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) to carbides in the pyrolysis gasification furnace was 1.2. From this result, when steam containing a metal component is used in a two-stage thermal decomposition gasification furnace for biomass, the gasification conversion rate, fuel gas yield and low gas calorific value are higher than those in Comparative Example 3 using tap water. Demonstrated to increase. 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 higher than that when tap water was used. In addition, the gasification conversion efficiency of biomass has improved to 68%. The concentration of the metal component contained in 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 tap water after the soft water treatment. The concentration of the metal component of the tap water used was Na: 6 mg / kg, K: 2 mg / kg, Ca: 5 mg / kg, Mg: 2 mg / kg, Al: 0.1 mg / kg per 1 kg of steam. The concentration of the metal component of tap water was measured by the same method as that of the metal component contained in the geothermal steam A.

According to the present invention, it has been found that the gasification efficiency of biomass and the yield of fuel gas and hydrogen can be improved by using steam containing a metal component such as geothermal steam in the pyrolysis gasification of biomass such as wood and agricultural waste. rice field. This makes it possible to provide a reduction in environmental load, an economical pyrolysis gasification of biomass, and a 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 body 2 Pyrolysis gas (biomass gas)
3 Biomass for thermal decomposition gasification 4 Biomass input part 5 Steam input part 6 Biomass for fuel 7 Combustion gas 8 Gasification furnace heating part 9 Burning furnace 10 Gasification reaction tower 11 Discharge part 12 Biomass gas discharge part 13 Gas separation Purification 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 Woody biomass 21 Carbonization furnace 22 Carbonated material 23 Combustion gas 24 Carbonized gasification furnace 25 Gasification furnace heating unit 26 Steam input part 27 Steam heat exchanger 28 Biomass gas 29 Steam 30 Air blower 31 Geothermal water reservoir 32 Gas-water separator 33 Steam 34 Steam heat exchanger 50 Thermal decomposition gasifier 52 Thermal decomposition gasifier 60 Biomass gas production System 62 Biomass gas production system 100 Hydrogen production system 200 Hydrogen production system P1 Thermal decomposition gasification process P2 Steam heating process P3 Biomass gas production process P4 Hydrogen production process S1 Burning operation S2 Gasification operation S3 Carbonization operation S4 Carbonized gasification operation WH Exhaust heat

Claims (14)

A biomass gas production method comprising a pyrolysis gasification step of obtaining biomass gas by using biomass as a raw material and gasifying it with steam containing a metal component. 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 the other part of the biomass and the steam.
The biomass gas production method according to claim 1, wherein the gasification operation uses the waste heat generated in the combustion operation as a heat source. The biomass gas production according to claim 1, wherein the pyrolysis gasification step comprises a carbonization operation for carbonizing the biomass to obtain carbonized material and a carbide gasification operation for obtaining the biomass gas from the carbonized material and the steam. Method. The biomass gas production method according to any one of claims 1 to 3, further comprising a steam heating step of heating the steam using the waste heat generated in the pyrolysis gasification step as a heat source. One of claims 1 to 4, wherein the metal component comprises 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 biomass gas according to the above method. Claimed that 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 10,000 mg with respect to 1 kg of the water vapor. Item 6. The biomass gas production method according to any one of Items 1 to 5. The biomass gas production step of obtaining the biomass gas by the biomass gas production method according to any one of claims 1 to 6.
A hydrogen production method comprising a hydrogen production step of reforming the biomass gas to generate hydrogen. The hydrogen production step according to claim 7, wherein 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. Hydrogen production method. A biomass gas production system having a pyrolysis gasification device that uses biomass as a raw material and gasifies it with steam containing metal components to obtain biomass gas. 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 waste heat generated in the combustion furnace to the gasification furnace. The biomass gas production according to claim 9, wherein the pyrolysis gasification apparatus includes a carbonization furnace that carbonizes the biomass to obtain carbonized material, and a carbide gasification furnace that obtains the biomass gas from the carbonized material and the steam. system. The biomass gas production system according to any one of claims 9 to 11, further comprising a steam heating means for heating the steam using the waste heat generated by the pyrolysis gasification device as a heat source. The 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 generate hydrogen. The hydrogen production apparatus has a reaction bed filled with a composite reforming catalyst and has a reaction bed.
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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