JP6777441B2 - Power generation system - Google Patents

Description

The present invention relates to a power generation system that uses off-gas generated when synthesizing fuel from biomass resources as fuel for a solid oxide fuel cell to generate power.

In recent years, there have been various liquid fuel manufacturing systems that manufacture liquid fuel from biomass resources such as wood and algae (hereinafter also referred to as biomass) with the aim of countering soaring fuel prices, reducing the burden on the global environment, and facilitating fuel security. It has been proposed (eg, Patent Document 1 and Patent Document 2).
Hereinafter, the techniques disclosed in Patent Document 1 and Patent Document 2 will be described, and the reference numerals used in each Patent Document are shown in parentheses for reference.
In the technique disclosed in Patent Document 1, the biomass (11) is dried using the dryer (12), the biomass (11) is crushed by the crusher (13), and the gas is gasified by the gasifier (14). To be. The produced gas 110 generated by gasification is dust-removed and refined, and then supplied to the liquid fuel synthesizer (22) for use in the synthesis of liquid fuel. Since the exhaust gas (24) (off gas) separated from the liquid fuel at that time still has a calorific value, it is burned in the combustion furnace (26), and a part of the combustion furnace exhaust gas (27) is dried. It is supplied to the vessel (12) and used as a heat source for drying the biomass (11). (See paragraphs [0023], [0024] and [0047], and FIG. 1 and the like.)

In the technique disclosed in Patent Document 2, a gasifier (11) that gasifies a raw material (91) to generate a gas (93) containing carbon monoxide and hydrogen, and a gasifier (11) are charged with water vapor. A water vapor supply means (13) to be supplied, and a liquid fuel conversion device (3) for producing a liquid fuel by synthesizing carbon monoxide and hydrogen contained in the gas (93) generated in the gasification furnace (11). , Equipped with a generator (4) that generates power using surplus gas (off gas) generated in the liquid fuel conversion device (3) as fuel, and at least the discharge side of the gasifier (11) is set to a temperature higher than the decomposition temperature of tar such as methane. Control eliminates the need for a gas refiner to remove tar (see patent claims, paragraphs [0019], [0023] and FIG. 3).
The liquid fueling device (3) is composed of water and the surplus gas from the composite of the FT synthesizer (33) that synthesizes carbon monoxide and hydrogen by the FT method (Fischer-Tropsch method) and the FT synthesizer (33). Is provided with a cooling separation unit (35) for extracting light oil (94) as a liquid fuel by cooling separation.
In Patent Document 2, biomass is mentioned as an example of the raw material (91), and a fuel cell is mentioned as an example of the generator (4).

Japanese Patent No. 4658980 Japanese Patent No. 5527743

In each of the techniques disclosed in Patent Document 1 and Patent Document 2, effective use of off-gas is realized by using off-gas generated in the liquid fuel manufacturing apparatus for drying biomass. However, in the liquid fuel manufacturing apparatus, off-gas is realized. It is desired that the product can be used more efficiently and for a wide range of purposes.

Further, in the technique disclosed in Patent Document 2, as described above, the excess gas is cooled and separated from the composite of the FT synthesis unit (33) to separate the light oil (94). In order to cool the surplus gas and separate the light oil (94), it is necessary to cool the surplus gas to the outside air temperature or lower. At the time of this cooling, the water vapor contained in the gas (93) generated in the gasification furnace (11) becomes water (liquid) and is separated from the surplus gas. When such surplus gas is supplied to the fuel cell as fuel, carbon is precipitated at the fuel electrode because the amount of water vapor contained in the surplus gas is small, which may significantly deteriorate the performance of the fuel cell.

In the technique disclosed in Patent Document 2, the gas (93) generated in the gasification furnace (11) is controlled by controlling at least the discharge side of the gasification furnace (11) to be equal to or higher than the decomposition temperature of tar as described above. It suppresses the residual tar in the gas and eliminates the need for a gas purification device. However, even if the gasification furnace (11) is controlled to have a tar decomposition temperature or higher, the gas (93) generated by the gasification furnace (11) contains a small amount of hydrogen sulfide. In the technique disclosed in Patent Document 2, since the gas purification device is not installed, this hydrogen sulfide may be supplied to the fuel cell. It is known that hydrogen sulfide poisons the fuel electrode of a fuel cell even at a small concentration of several ppm and significantly deteriorates the performance of the fuel cell.

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a power generation system capable of efficiently and widely using off-gas generated when synthesizing fuel.

(1) In order to achieve the above object, in the power generation system of the present invention, the biomass resource is supplied from the biomass transport path for supplying the biomass resource, the steam supply line for supplying steam, and the biomass transport path. At the same time, a gasification furnace in which at least the steam is supplied as a gasifying agent from the steam supply line to gasify the biomass resource to generate a generated gas, and a fuel synthesis device that synthesizes fuel using the generated gas. The off-gas line that supplies the off-gas separated from the fuel, the solid oxide fuel cell that supplies the off-gas from the off-gas line and generates power using the off-gas, and the steam supply line are branched. At the same time, the off-gas line or the solid oxide fuel cell is connected to the off-gas line, and a part of the water vapor of the water vapor supply line is mixed with the off-gas. The molar ratio (H ₂ O / C) of the steam to the carbon contained in the biomass resource is a lower limit set from the viewpoint of suppressing a decrease in the amount of hydrogen H ₂ produced, and the inside of the gasification furnace. It is characterized in that the gas agent is supplied so as to fall within the range defined by the upper limit value set from the viewpoint of suppressing the temperature drop of .

In the power generation system according to at least one embodiment of the present invention, biomass resources are gasified by a gasifier to generate produced gas, off-gas is separated from the produced gas from the fuel synthesized by the fuel synthesizer, and the off-gas is used as fuel. As a result, power can be generated by a highly efficient solid oxide fuel cell. That is, it is possible to generate electricity with high efficiency by a solid oxide fuel cell using biomass resources.

Further, since the power generation system according to at least one embodiment of the present invention uses water vapor as a gasifying agent, the gas shift reaction of biomass resources is activated in the gasification furnace, and a large amount of hydrogen (for example, water vapor is supplied to the produced gas). It is possible to generate (about twice as much as the case without it). As a result, the off-gas separated / removed from the fuel can be made into a methane-rich gas by synthesizing the fuel using the generated gas containing hydrogen. Therefore, methane-rich off-gas can be used as the fuel gas for the solid oxide fuel cell, and the efficiency at the power generation end can be improved as compared with gas engine power generation using off-gas.
The present invention does not exclude the use of other gasifying agents in addition to water vapor, and of course, only water vapor is used as the gasifying agent, and water vapor and oxygen (including oxygen-enriched air) are used. Both may be used, or both water vapor and air may be used. In this case, a steam supply line or an oxygen supply line (including an air supply line and an oxygen-enriched air supply line) may be connected to a transport path for supplying the gasifying agent to the gasifier, or gas. A steam supply line and an oxygen supply line may be directly connected to the gasifier. Alternatively, a steam supply line is connected to an oxygen supply line directly connected to the gasifier, and a gasifying agent consisting of steam and oxygen (including air and oxygen-enriched air) is gasified from the oxygen supply line. It may be supplied to the furnace. On the contrary, the oxygen supply line may be connected to the steam supply line directly connected to the gasifier, and the gasifying agent composed of steam and oxygen may be supplied to the gasifier from the steam supply line.

Furthermore, since steam is mixed in advance with the off-gas supplied to the solid oxide fuel cell, the molar ratio (S / C) of steam and carbon in the off-gas is adjusted appropriately, and the fuel electrode of the solid oxide fuel cell is used. It is possible to avoid the precipitation of carbon in the fuel cell and to avoid the deterioration of the performance of the fuel cell.

(2) it is preferable to pre-liver Le ratio _(H 2 O / C) supplies the gasifying agent to fall within a range of 1.5 to 4.
The power generation system according to at least one embodiment of the present invention supplies a gasifying agent so that the molar ratio (H ₂ O / C) of water vapor to carbon contained in biomass is in the range of 1.5 to 4. As a result, the gas shift reaction is activated, and the off-gas methane richness can be promoted. Here, when the H ₂ O / C exceeds 4, the temperature in the gasification furnace is lowered, and the gas shift reaction is lowered. That is, the amount of generated gas effective for fuel synthesis may decrease, which may hinder the power generation of the solid oxide fuel cell. Further, when H ₂ O / C is less than 1.5, the amount of H ₂ produced decreases, so that the amount of produced gas required for fuel synthesis decreases, and the yield of fuel obtained by synthesis decreases. ..
(3) It is preferable to have a measuring means for measuring the molar ratio (H ₂ O / C) and an on-off valve interposed in the steam mixing line and controlled based on the measurement result of the measuring means. ..

( 4 ) It is preferable that the fuel refiner is provided with a gas refining device for purifying the produced gas produced by the gasifier, and the fuel synthesizer synthesizes fuel using the produced gas purified by the gas refinery. ..
In the power generation system according to at least one embodiment of the present invention, the produced gas produced in the gasifier is purified by the gas purification apparatus to remove hydrogen sulfide. Therefore, hydrogen sulfide is used as the off-gas derived from the produced gas after purification. Is not contained or is hardly contained. Therefore, when off-gas is supplied to the fuel cell as fuel, it is possible to prevent hydrogen sulfide from poisoning the fuel electrode of the fuel cell and deteriorating the performance of the fuel cell.

(5) A dryer for drying the biomass resources before supplying the gas to the gasifier, and a battery exhaust gas line for supplying the battery exhaust gas discharged from the solid oxide fuel cell to the dryer. Is preferable.
( 6 ) It is preferable to include a gas turbine and a generator driven by the gas turbine, and to provide a battery exhaust gas line that supplies the battery exhaust gas discharged from the solid oxide fuel cell as fuel to the gas turbine. ..

In the power generation system according to at least one embodiment of the present invention, the battery exhaust gas discharged from the solid oxide fuel cell is supplied to the gas turbine as fuel, and the gas turbine drives the generator to generate electricity. You can use it to get more power. Moreover, since the battery exhaust gas discharged from the solid oxide fuel cell is heated by the exothermic reaction in the solid oxide fuel cell, the thermal efficiency of the entire system and the power generation efficiency of the entire system can be improved. it can.

( 7 ) The dryer is provided to dry the biomass resources before being supplied to the gasifier, and the battery exhaust gas discharged from the solid oxide fuel cell or the turbine exhaust gas discharged from the gas turbine is dried. It is preferable to provide an exhaust gas line to supply the gas.

In the power generation system according to at least one embodiment of the present invention, the biomass resources containing a large amount of water are dried by a dryer before being supplied to the gasifier, so that the biomass resources can be easily transported to the gasifier and the gasifier. Fuel can be supplied without reducing the thermal efficiency of the system. Further, by removing the water content of the biomass resource, it is possible to facilitate the combustion control in the gasification furnace.

( 8 ) It is preferable that the gasification furnace is a jet bed type gasification furnace.

In the power generation system according to at least one embodiment of the present invention, the temperature of the generated gas can be raised by adopting a jet bed system for the gasification furnace. In other words, in the jet bed type gasification furnace, compared to other types of gasification furnaces such as the fixed bed type and the circulating fluidized bed type, the flow velocity in the furnace is faster, so fewer particles stay in the furnace, and the particles are used from the generated gas. Since the amount of heat absorbed is small, the temperature of the generated gas can be raised. Therefore, it is possible to create an atmosphere inside the furnace in which methane is easily generated. In particular, since water vapor is included in the gasifying agent, the ratio of hydrogen to carbon monoxide can be set to 2: 1 and the optimum produced gas properties for fuel synthesis can be obtained, so that linear carbonization is efficiently performed in the fuel synthesis process. As a result of the generation of hydrogen, a large amount of methane, which is not suitable for jet fuel, is also produced, so that a more methane-rich off-gas suitable for a solid oxide fuel cell can be supplied. Here, methane is produced in the process of gasification of biomass and in the process of synthesis of fuel. Assuming that the amount of methane generated in the gasification furnace is 1, the amount of methane generated by fuel synthesis is 1.2 to 1.5.
Here, the reaction formula of methane produced in the process of gasification of biomass is as shown in the following formula (1).
CO + 3H ₂ → CH ₄ + H ₂ O ... (1)
The reaction formula of methane produced in the process of fuel synthesis (FT synthesis) is as shown in the following formula (2).
nCO + (2n + 1) H ₂ → C _n H _{2n + 2} + H ₂ O ... (2)

According to the present invention, a biomass resource is gasified by a gasifier to generate a produced gas, off-gas is separated from the produced gas from the fuel synthesized by a fuel synthesizer, and the off-gas is used as a fuel to produce a highly efficient solid. Power can be generated by an oxide fuel cell. That is, it is possible to generate electricity with high efficiency by a solid oxide fuel cell using biomass resources.
Then, since electric power can be extracted from the off-gas generated when fuel is produced from the biomass resource, it can be used for various electric devices rather than using the off-gas as heat energy.
Since water vapor is included in the gasifying agent, the gas shift reaction is actively carried out and a large amount of hydrogen is produced. As a result, the off-gas separated / removed from the fuel can be used as the fuel of the solid oxide fuel cell as a methane-rich gas, so that the solid oxide fuel cell can generate electricity with high efficiency.
Further, since steam is mixed in advance with the off-gas supplied to the solid oxide fuel cell, the molar ratio (S / C) of steam and carbon in the off-gas is adjusted appropriately, and the fuel electrode of the solid oxide fuel cell is used. It is possible to avoid the precipitation of carbon in the fuel cell and to avoid the deterioration of the performance of the fuel cell.
Therefore, the off-gas generated when fuel is produced from biomass resources can be efficiently and widely used.

It is a block diagram which shows the structure of the power generation system which concerns on at least one Embodiment (1st Embodiment) of this invention. It is a block diagram which shows the structure of the power generation system which concerns on at least another 1 Embodiment (2nd Embodiment) of this invention. It is a block diagram which shows the structure of the power generation system which concerns on at least another 1 Embodiment (third Embodiment) of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Each of the embodiments shown below is merely an example, and there is no intention of excluding the application of various modifications and techniques not specified in each of the following embodiments. Each configuration of each of the following embodiments can be variously modified and implemented without departing from the gist thereof, and can be selected as necessary or combined as appropriate.

[1.1 Embodiment (first embodiment)]
Hereinafter, one embodiment will be described with reference to FIG.
FIG. 1 is a block diagram showing a configuration of a power generation system according to at least one embodiment of the present invention.

[1-1. Constitution]
The power generation system 1 shown in FIG. 1 uses off-gas 130 generated when fuel is produced from a biomass resource (hereinafter, also referred to as biomass) 100 to generate power. Specifically, as shown in FIG. 1, the power generation system 1 of the present embodiment includes a dryer 2, a crusher 3, a gasifier 4, a high-temperature heat exchanger 5, a dust remover 6, a low-temperature heat exchanger 7, Gas purification device 8, booster 9, decarburization device 10, liquid fuel synthesizer (fuel synthesizer) 11, gas-liquid separator 12, solid oxide fuel cell (hereinafter referred to as "SOFC") 13 And an air compressor 13a.

The inlet of the dryer 2 is connected to a biomass storage facility (not shown) by a biomass supply path L1 (for example, a conveyor, a screw feeder, a pipe), and the dryer 2 is connected to the dryer 2 from the storage facility via the biomass supply path L1. Biomass resources 100 containing a large amount of water such as wood (firewood, charcoal, chips, pellets, etc.) are supplied. The dryer 2 dries the biomass 100 to obtain a dry biomass 100A. The outlet of the dryer 2 is also connected to the inlet of the crusher 3 by a biomass transfer path L2 (for example, a conveyor, a screw feeder, a pipe), and the dried biomass 100A passes through the biomass transfer path L2 from the dryer 2. It is supplied to the crusher 3 via. The heat source for drying the biomass 100A in the dryer 2 will be described later.
The crusher 3 crushes the dry biomass 100A to obtain biomass 100B having a particle size suitable for gasification. The outlet of the crusher 3 is connected to the biomass supply section of the gasification furnace 4 by a biomass transfer path L3 (for example, a conveyor, a screw feeder, a pipe), and is crushed from the crusher 3 to a particle size suitable for gasification. The biomass 100B is supplied to the gasifier 4 via the biomass transfer path L3.

The gasification furnace 4 gasifies the crushed biomass 100B to generate a gas (hereinafter referred to as a production gas) 110 which is a raw material for the fuel to be produced.
The gasifier 4 is of a jet bed type in which biomass 100B is ejected together with the gasifying agent 50 by a burner (not shown), and oxygen 50A is supplied from the oxygen pipe (oxygen supply line) L53 as the gasifying agent 50. At the same time, steam 50B is supplied from the steam pipe (steam supply line) L52. Therefore, the produced gas 110 becomes a methane-rich gas.
This is because (1) since the gasifying agent 50 contains water vapor 50B, the gas shift reaction (CO + H ₂ O → CO ₂ + H ₂ ) is actively carried out in the gasifier 4, and the produced gas 110 contains a large amount of hydrogen. Point, (2) Since the gasification furnace 4 is a jet bed type, compared to other types of gasification furnaces such as fixed bed type and fluidized layer type, the flow velocity in the furnace is faster, so fewer particles stay in the furnace and particles are present. This is because the atmosphere in which methane (CH ₄ ) is easily generated is synergistically created from the two points that the amount of heat absorbed from the produced gas is reduced and the temperature of the produced gas 110 in the furnace is increased.
Although the temperature of the produced gas 110 in the furnace is high, the time for the produced gas 110 to stay in the furnace is short because the flow velocity in the furnace is high. Therefore, unlike the fuel generation system (100) disclosed in Patent Document 2, methane (CH ₄ ) is not completely decomposed in the gasification furnace (11).
Here, it is preferable to supply the gasifying agent 50 so that the molar ratio (H ₂ O / C) of the water vapor 50B and the carbon contained in the biomass 100B is in the range of 1.5 to 4. As a result, the gas shift reaction is activated, so that the off-gas 130 of the liquid fuel synthesizer 11 can be enriched with methane, as will be described later.

Here, if the molar ratio (S / C) of water vapor (S: Steam) and carbon (C) in the off-gas 130 is low, carbon precipitation occurs in the cell (fuel electrode) of SOFC13 and the performance of SOFC13 deteriorates. There is a risk. When naphtha, which is a light fuel, is distilled in the gas-liquid separator 12, it is generally cooled to around 35 ° C., and when the hydrocarbon fuel 120 and the off-gas 130 are separated, the water vapor becomes water and off-gas. Separated from 130. Therefore, the amount of water vapor contained in the off-gas 130 may be insufficient. Therefore, the carbon precipitation can be avoided by extracting a part of the steam 50B of the gasifying agent 50 supplied to the gasifier 4 and mixing it into the off-gas 130 so that the molar ratio (S / C) is not insufficient. It has a structure. As a result, it is possible to suppress a deterioration in the performance of the SOFC 13 due to carbon precipitation at the fuel electrode of the SOFC 13.

As a specific configuration, as shown in FIG. 1, a bypass line (water vapor mixing line) L52'and a gas transport path (hereinafter, also referred to as "off gas line") L13 for supplying the off-gas 130 to the SOFC 13 described later are interposed. A measuring means (not shown) that measures the molar ratio (S / C) of the off-gas 130 mounted and an on-off valve (for example, an electromagnetic valve) that is interposed in the bypass line L52'and controlled based on the measurement result of the measuring means. 20 and are provided.

The bypass line L52'connects a steam pipe (steam supply line) L52, which will be described later to supply steam 50B to the gasifier 4, and an off-gas line L13, and partially extracts steam 50B from the steam pipe L52, and extracts the steam pipe L52. This is for mixing the steam 50B into the off-gas 130 flowing through the off-gas line 13 by bypassing the gasification furnace 4.
Further, when the molar ratio (S / C) of the off-gas 130 measured by the measuring means is lower than a predetermined threshold value (for example, 2.0 to 5.0), the on-off valve 20 is controlled to open. When the molar ratio (S / C) of the off-gas 130 measured by the measuring means exceeds a predetermined threshold value, the on-off valve 20 is controlled to close.
Since the steam 50B used as the gasifying agent is in excess, even if a part of the steam 50B is extracted by the bypass line L52', the steam used as the gasifying agent in the gasifier 4 is not insufficient, and the steam 50B is 500. Since the temperature is as high as about ° C., it can be supplied to SOFC 13 having a high operating temperature without heating by the bypass line L52'.

A part of the water vapor 50B of the gasifying agent 50 may be constantly extracted from the bypass line 52'and mixed into the off-gas 130. In this case, the measuring means for measuring the molar ratio (S / C) and the on-off valve 20 can be omitted.

The gas outlet of the gasification furnace 4 is connected to the gas side inlet of the high temperature heat exchanger 5 by a gas transport path (for example, a duct or a pipe) L4, and the produced gas 110 generated by the gasification furnace 4 is gasified. It is supplied from the furnace 4 to the gas side inlet of the high temperature heat exchanger 5 via the gas transfer path L4. The gas side outlet of the high temperature heat exchanger 5 is connected to the inlet of the dust removing device 6 by a gas transport path (for example, a duct or a pipe) L5, and the generated gas 110 is passed from the high temperature heat exchanger 5 via the gas transfer path L5. Is supplied to the dust remover 6. The dust removing device 6 removes the generated gas 110 to obtain the generated gas 110A from which soot and dust have been removed. The outlet of the dust remover 6 is connected to the gas side inlet of the low temperature heat exchanger 7 by a gas transport path (for example, a duct or a pipe) L6, and the generated gas 110A is low temperature from the dust remover 6 via the gas transport path L6. It is supplied to the heat exchanger 7.

Further, the steam side inlet of the low temperature heat exchanger 7 is connected to a steam source (for example, a steam boiler) (not shown) by a steam pipe L50, and the steam 50B is used as a heating medium from this steam source via the steam pipe L50. Is supplied to the low temperature heat exchanger 7. Further, the steam side outlet of the low temperature heat exchanger 7 is connected to the steam side inlet of the high temperature heat exchanger 5 by the steam pipe L51, and the steam 50B is high from the low temperature heat exchanger 7 via the steam pipe L51. It is supplied to the heat exchanger 5. The steam side outlet of the high temperature heat exchanger 5 is connected to the gasifier 4 by a steam pipe L52, and steam 50B is supplied from the high temperature heat exchanger 5 to the gasifier 4 via the steam pipe L52.

With such a configuration, the high temperature heat exchanger 5 and the low temperature heat exchanger 7 exchange heat between the generated gas 110 generated in the gasifier 4 and the steam 50B to raise the steam 50B constituting the gasifying agent. Warm up. The heated steam 50B is supplied to the gasification furnace 4.

The gas side outlet of the low temperature heat exchanger 7 is connected to the inlet of the gas purification device 8 by a gas transport path (for example, a duct or a pipe) L7, and the low temperature is low from the low temperature heat exchanger 7 via the gas transport path 7. The generated gas 110A that has passed through the heat exchanger 6 and has soot and dust removed by the dust removing device 6 is supplied to the gas refining device 8. The gas purification apparatus 8 purifies the produced gas 110A by removing unnecessary components such as hydrogen sulfide contained in a trace amount.

The outlet of the gas purification device 8 is connected to the inlet of the booster 9 by a gas transfer path (for example, a duct or a pipe) L8, and is purified by the gas purification device 8 from the gas purification device 8 via the gas transfer path L8. The generated gas 110B is supplied to the booster 9. The booster 9 boosts the refined produced gas 110B for the production of liquid fuel.
The outlet of the booster 9 is connected to the inlet of the decarburization device 10 by a gas transport path (for example, a duct or a pipe) L9, and is boosted by the booster 9 from the booster 9 via the gas transport path L9. The generated gas 110B is supplied to the decarburization device 10.
The decarburization device 10 removes the carbonic acid component from the boosted product gas 110B. As a result, the efficiency of liquid fuel synthesis by the liquid fuel synthesis device 11 in the subsequent stage is improved.

The outlet of the decarburization device 10 is connected to the inlet of the liquid fuel synthesis device 11 by a gas transport path (for example, a duct or a pipe) L10, and the generated gas 110C from which the carbon dioxide component has been removed by the decarburization device 10 is gas transport. It is supplied to the liquid fuel synthesizer 11 via the passage L10.
The liquid fuel synthesizer 11 synthesizes the hydrocarbon fuel 120 using the Fischer-Tropsch (FT) method. That is, the hydrocarbon fuel 120 is synthesized from carbon monoxide and hydrogen in the produced gas 110C from which the carbonic acid component has been removed by using a catalytic reaction. Here, by the FT method, a plurality of types of hydrocarbon gases (CnH ₂ n, n are 1 or more and 100 or less) are synthesized as the hydrocarbon fuel 120 in a mixed state, and gasoline, light oil, kerosene, jet fuel, wax, etc. Can be obtained.

The outlet of the liquid fuel synthesizer 11 is connected to the inlet of the gas-liquid separator 12 by a gas transport path (for example, a duct or a pipe) L11, and the hydrocarbon fuel 120 synthesized by the liquid fuel synthesizer 11 is gas transport. It is supplied to the gas-liquid separator 12 via the passage L11.
The gas-liquid separator 12 cools and separates the hydrocarbon fuel 120 synthesized by the liquid fuel synthesizer 11, and removes the off-gas 130 and the off-gas 130, which are by-products (light hydrocarbon gas such as methane). Fractional distillation is performed with the completed liquid fuel, hydrocarbon fuel 120A (hereinafter, also referred to as liquid fuel 120A).
The off-gas outlet of the gas-liquid separator 12 is connected to the off-gas inlet of the SOFC 13 by a gas transport path (for example, a duct or a pipe) L13, and the off-gas 130 separated by the gas-liquid separator 12 passes through the gas transport path L13. Then, it is supplied as fuel gas to the fuel electrode of SOFC13.
Further, the hydrocarbon fuel outlet of the gas-liquid separator 12 is connected to the inlet of a recovery facility (not shown) by a pipe L12, and the hydrocarbon fuel 120A is recovered to the recovery facility via the pipe L12.

なお、ＳＯＦＣ１３は、イオン伝導率を高めるために作動温度が約７００〜１０００℃程度と高いため、オフガス１３０をＳＯＦＣ１３に燃料として供給する前に予熱するのが好ましい。予熱の態様としては何ら限定されないが、上述したように、ガス化剤として使用される水蒸気５０Ｂの一部をオフガス１３０に混入してもよい。或いは、ＳＯＦＣ１３の作動温度が高いため、燃料極から排出されるオフガス（電池排ガス）１３０Ａも高温であることから、これらの高温のオフガス１３０Ａを用いて気液分離器１２出口のオフガス１３０を予熱するようにしてもよい。具体的な構成としては、例えば、オフガス１３０Ａが流通する配管（電池排ガスライン）Ｌ１４に分岐管を設け、この分岐管と熱交換する熱交換器をオフガスラインＬ１３に介装する構成が考えられる。 SOFC13 is known as a highly efficient high-temperature fuel cell having a high operating temperature of about 700 to 1000 ° C. in order to increase ionic conductivity. In SOFC13, ceramics such as zirconia ceramics are used as the electrolyte, and hydrocarbon-based gases such as hydrogen (H ₂ ), carbon monoxide (CO), and methane (CH ₄ ) are used as fuel. Here, the SOFC 13 is supplied with the off-gas 130 as described above for the fuel electrode. The air inlet of the SOFC 13 is connected to the air discharge port of the air compressor 13a by the pipe L15, and high-pressure air 140 is supplied from the air compressor 13a to the air electrode of the SOFC 13 via the pipe L15.
Here, as described above, the produced gas 110 generated in the gasification furnace 4 is a methane-rich gas. Table 1 below, except the product gas 110 at the outlet of the gasification furnace 4, product gas 110C at the outlet of the CO 2 removal unit 10, a representative gas _{(N 2, H} 2 O in the offgas 130 of the outlet of the gas-liquid separator 12 gas, ie _CO, indicates the molar ratio of _{H 2, CO 2, CH 4} ), product gas 110, various component gas purifier 8, CO 2 removal unit 10, the liquid fuel synthesis apparatus 11, the gas-liquid separator 12, etc. Is separated and removed to become off-gas 130, but methane (CH ₄ ) is hardly removed. Therefore, this methane-rich off-gas 130 is effectively used as a fuel for SOFC 13.

Since the operating temperature of SOFC 13 is as high as about 700 to 1000 ° C. in order to increase the ionic conductivity, it is preferable to preheat the off-gas 130 before supplying it to SOFC 13 as fuel. The mode of preheating is not limited, but as described above, a part of steam 50B used as a gasifying agent may be mixed in the off-gas 130. Alternatively, since the operating temperature of the SOFC 13 is high, the off-gas (battery exhaust gas) 130A discharged from the fuel electrode is also high in temperature. Therefore, the off-gas 130 at the outlet of the gas-liquid separator 12 is preheated by using these high-temperature off-gas 130A. You may do so. As a specific configuration, for example, a configuration is conceivable in which a branch pipe is provided in the pipe (battery exhaust gas line) L14 through which the off-gas 130A flows, and a heat exchanger that exchanges heat with the branch pipe is interposed in the off-gas line L13.

Here, as described above, the SOFC 13 has a high operating temperature of about 700 to 1000 ° C. in order to increase the ionic conductivity, and the off-gas 130A discharged from the fuel electrode is also high. Therefore, the power generation system 1 of the present embodiment supplies these off-gas 130A to the dryer 2 and uses them as a heat source for drying the biomass 100. Specifically, the outlet of the pipe L14 connected to the off-gas discharge port of the SOFC 13 is communicated with the inside of the dryer 2 (the drying chamber to which the biomass 100 is supplied). As a result, the off-gas 130A is supplied to the drying chamber via the pipe L14, and the biomass 100 is directly dried by these off-gas 130A.
Alternatively, the dryer 2 may be provided with a jacket for indirect heating, the outlet of the pipe L14 may be connected to this jacket, and the biomass 100 in the drying chamber may be indirectly heated by the off-gas 130A supplied to the jacket.

Biomass 100 often has a high water content due to its nature, and if it is used as it is, it is expected that there will be an obstacle to gasification, a significant decrease in plant efficiency, and a deterioration in handleability. Therefore, in a plant that handles biomass 100, it is common to include a dryer 2 that dries the biomass 100 as in the power generation system 1 of the present embodiment. Therefore, the dryer 2 is suitable as an effective use destination of the off-gas 130.

A pipe L16 is connected to the air discharge port of the SOFC 13, and the air 140A discharged from the air electrode of the SOFC 13 is discharged to the outside through the pipe L16. When the air 140A is hot enough to be used for drying the biomass 100, the air 140A is dried by connecting the air 140A pipe L16 to the drying chamber or jacket of the dryer 2 in the same manner as the off-gas 130A pipe L14. It may be used as a drying heat source for the vessel 2.

[1-2. Action / effect]
According to the power generation system 1 as one embodiment (first embodiment) of the present invention, power is generated by the highly efficient SOFC 13 using the off-gas 130 separated from the hydrocarbon fuel 120 synthesized by the liquid fuel synthesizer 11 as fuel. (SOFC13 can generate high-efficiency power generation).
Further, by using the steam 50B as a part of the gasifying agent 50, the gas shift reaction can be activated by the steam 50B, and by adopting the gasification furnace 4 as a jet bed type, another type of gasification furnace can be used. The temperature of the produced gas 110 can be raised as compared with the above. In particular, since water vapor is included in the gasifying agent, the ratio of hydrogen to carbon monoxide can be set to 2: 1 and the optimum produced gas properties for fuel synthesis can be obtained, so that linear carbonization is efficiently performed in the fuel synthesis process. As a result of the generation of hydrogen, a large amount of methane, which is not suitable for jet fuel, is also produced, so that a more methane-rich off-gas suitable for a solid oxide fuel cell can be supplied. Here, methane is produced in the process of gasification of biomass and in the process of synthesis of fuel. Assuming that the amount of methane generated in the gasification furnace is 1, the amount of methane generated by fuel synthesis is 1.2 to 1.5.
Here, the reaction formula of methane produced in the process of gasification of biomass is as shown in the following formula (1).
CO + 3H ₂ → CH ₄ + H ₂ O ... (1)
The reaction formula of methane produced in the process of fuel synthesis (FT synthesis) is as shown in the following formula (2).
nCO + (2n + 1) H ₂ → C _n H _{2n + 2} + H ₂ O ... (2)
In this way, the off-gas 130 can be made into a methane-rich gas, and by using this off-gas 130 as the fuel for the SOFC 13, the power generation end efficiency in the SOFC 13 can be improved.

Further, since the off-gas 130 is used for power generation, the obtained power can be supplied to various electric devices used in the power generation system 1 or can be transmitted to the outside of the power generation system 1. Biomass-derived electricity can be used for various purposes,
Therefore, the off-gas 130 generated when the liquid fuel 120A is produced can be efficiently and widely used.

Further, by drying the biomass resource 100 containing a large amount of water with the dryer 2 before supplying it to the gasifier 4, the transport to the gasifier 4 is facilitated, and the latent heat of the water deprives the amount of heat. It is possible to suppress the decrease in thermal efficiency in the gasification furnace 4 by suppressing the waste.
Further, by removing the water content of the biomass resource 100, gasification control (control of partial combustion) in the gasification furnace 4 can be facilitated. That is, normally, the biomass resource 100 has a high water content, and if it is transported to the gasification furnace 4 as it is, problems such as adhesion and blockage occur in the transport process. However, by drying the biomass resource 100 and removing the water content, handling becomes easier. Gasification control (control of partial combustion) is also facilitated.
Then, by using the off-gas 130A discharged from the SOFC 13 as a heat source for drying the biomass 100, the off-gas 130 can be used more effectively.

Further, since the produced gas 110A generated in the gasification furnace 4 is purified by the gas refining apparatus 8 to remove hydrogen sulfide, the off-gas 130 derived from the produced gas 110A does not contain (or hardly contains) hydrogen sulfide. ). Therefore, when the off-gas 130 is supplied to the SOFC 13 as fuel, it is possible to prevent hydrogen sulfide from poisoning the fuel electrode of the SOFC 13 and deteriorating the performance of the SOFC 13.

Further, since a part of the steam 50B of the gasifying agent 50 supplied to the gasifier 4 is extracted and mixed into the off-gas 130, the molar ratio (S / S /) of the steam (S: Steam) to the carbon (C) in the off-gas 130 C) can be set to an appropriate range, and it is possible to prevent carbon from being precipitated at the fuel electrode of SOFC 13 and deteriorating the performance of SOFC 13.

[2. Another 1 Embodiment (2nd Embodiment)]
Hereinafter, another embodiment (second embodiment) will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[2-1. Constitution]
In the first embodiment as the above-mentioned one embodiment, the off-gas 130A and the air 140A discharged from the SOFC 13 were supplied to the dryer 2. On the other hand, the power generation system 1A of the present embodiment further includes a gas turbine 14 and a generator 15, and uses off-gas 130A and air 140A discharged from the SOFC 13 as fuel and combustion air for the gas turbine 14.
Hereinafter, the power generation system 1A will be specifically described. The gas turbine 14 and the generator 15 connected to the rotating shaft 14a of the gas turbine 14 are combined with the SOFC 13 which is a generator to form a combined power generation system.
Further, the off-gas inlet (fuel inlet) of the combustor 14b of the gas turbine 14 is connected to the off-gas outlet of the SOFC 13 by the pipe L14. Further, the air inlet of the combustor 14b is connected to the air outlet of the SOFC 13 by the pipe L16. As a result, the off-gas 130A is supplied from the SOFC 13 to the combustor 14b via the pipe L14, and the air 140A is supplied from the SOFC 13 via the pipe L16.

As described above, since the operating temperature of the SOFC 13 is as high as about 700 to 1000 ° C., the off-gas 130A discharged from the fuel electrode and the air 140A discharged from the air electrode also become hot, and these high-temperature off-gas 130A and high-temperature air 140A and 140A are supplied to the combustor 14b of the gas turbine 14 to be burned, and the gas turbine 14 is rotated by the combustion gas generated in the combustor 14b to rotationally drive the generator 15 to generate power. That is, the off-gas 130A and the air 140A are supplied to the gas turbine 14 via the pipes L14 and L16, and the heat, pressure and residual fuel content of the off-gas 130A and the heat and pressure of the air 140A are generated by the gas turbine 14. I am using it for.
The turbine exhaust gas 150 discharged from the gas turbine 14 after rotationally driving the gas turbine 14 is an exhaust gas path (turbine exhaust gas line) L17 (for example, a turbine exhaust gas line) connected to an exhaust gas outlet on the downstream side of the exhaust gas from the final turbine blade of the gas turbine 14. It is purified by a purification treatment device interposed in the exhaust gas path L17 as needed via a duct or a pipe) and released to the atmosphere.
Since other configurations are the same as those of the first embodiment, the description thereof will be omitted.

[2-2. Action / effect]
According to the present embodiment, the same actions / effects as those of the first embodiment can be obtained, and the following actions / effects can be obtained.
That is, since the high-temperature off-gas 130A and the high-temperature air 140A discharged from the SOFC 13 are effectively used to generate power (combined power generation) by the combined cycle method using the SOFC 13 and the gas turbine 14, only the SOFC 13 is used. It is possible to further improve the power generation efficiency compared to the power generation.
In particular, since the off-gas 130A is heated by the exothermic reaction in the SOFC 13, the combustion efficiency of the gas turbine 14 can be improved by using it as a fuel for the gas turbine 14. Therefore, the power generation efficiency of the gas turbine 14 can be improved.
While the power generation efficiency when the off-gas 130 is used as the fuel for the gas engine is about 40%, the power generation efficiency is achieved by combining the power generation by the SOFC 13 and the power generation by the gas turbine 14 using the off-gas 130 as the fuel. Can be improved up to about 50%.

Further, since steam 50B is used as a component of the gasifying agent 50, compared to the case where only oxygen is used as a component of the gasifying agent 50, the generated gas 110 of the gasification furnace 4 and thus the gas turbine 14 are fueled. As a component of the off-gas 130A of SOFC 13 supplied as, CO decreases while H ₂ increases. Therefore, the ignitability of the off-gas 130A in the gas turbine 14 is improved.

[3. Another 1 Embodiment (3rd Embodiment)]
[3-1. Constitution]
Hereinafter, another embodiment (third embodiment) will be described with reference to FIG. The same components as those in the first embodiment and the second embodiment are designated by the same reference numerals, and the description thereof will be omitted.
The turbine exhaust gas 150 discharged from the gas turbine 14 after rotationally driving the gas turbine 14 has a relatively high temperature of about 250 ° C. Therefore, the power generation system 1B of the present embodiment supplies the turbine exhaust gas 150 to the dryer 2 and uses it as a heat source for drying the biomass 100. Specifically, the outlet of the exhaust gas path L17 is continuously connected to the drying chamber of the dryer 2, and the turbine exhaust gas 150 discharged from the gas turbine 14 is supplied to the drying chamber via the exhaust gas path L17. The turbine exhaust gas 150 directly dries the biomass 100.
Alternatively, the dryer 2 may be provided with a jacket for indirect heating, the outlet of the exhaust gas path L17 may be connected to this jacket, and the biomass 100 in the drying chamber may be indirectly heated by the turbine exhaust gas supplied to the jacket. ..

Due to its nature, Biomass 100 often has a high water content, and if it is used as it is, it is expected that there will be an obstacle to gasification, a significant decrease in plant efficiency, and a deterioration in handleability. Therefore, in a plant that handles the biomass 100, it is common to include a dryer 2 that dries the biomass 100 as in the power generation system 1B of the present embodiment. Therefore, the dryer 2 is suitable as an effective use destination of the turbine exhaust gas 150 discharged from the gas turbine 14.
In addition to the turbine exhaust gas 150 discharged from the gas turbine 14, the off-gas 130A discharged from the SOFC 13 may be used as a drying heat source for the dryer 2 as in the first embodiment. Specifically, a branch transfer path (for example, a duct or a pipe) may be provided in the gas transfer path L14, and this branch path may be connected to the drying chamber or jacket of the dryer 2.
Since other configurations are the same as those of the second embodiment, the description thereof will be omitted.

[3-2. Action / effect]
According to the present embodiment, the same actions / effects as those of the second embodiment can be obtained, and the following actions / effects can be obtained.
That is, by drying the biomass resource 100 containing a large amount of water in the dryer 2 before supplying it to the gasifier 4, the effect of drying the biomass resource 100 in the dryer 2 in the first embodiment is obtained. A similar effect can be obtained.
That is, it is possible to facilitate the transfer to the gasification furnace 4 and suppress the loss of heat due to the latent heat of water to suppress the decrease in thermal efficiency in the gasification furnace 4.
In addition, the biomass resource 100 usually has a high water content, and if it is transported to the gasification furnace 4 as it is, problems such as adhesion and blockage occur in the transport process. However, by drying the biomass resource 100 and removing the water content, handling becomes easier. Gasification control (control of partial combustion) is also facilitated.
As described above, by using the turbine exhaust gas 150, which is the exhaust gas derived from the off-gas 130 and discharged from the gas turbine 14, as a heat source for drying the biomass 100, the off-gas 130 can be used more effectively.

[4. Others]
(1) In the above embodiment, oxygen 50A and steam 50B are used as the gasifying agent, but the gasifying agent is not limited to this as long as it contains at least water vapor. For example, as the gasifying agent, only water vapor may be used, both water vapor and oxygen may be used, or both water vapor and air (including oxygen-enriched air) may be used. ..

(2) In the second embodiment and the third embodiment, the gas turbine 14 and the air compressor 13a are provided separately, but they may be integrally configured. That is, the air compressor 13a may be configured by a compressor unit directly connected to the turbine shaft of the gas turbine.

(3) In each of the above embodiments, the biomass 100A was pulverized by the crusher 3 to a particle size suitable for gasification, but when the biomass pulverized to a predetermined particle size in advance is used, the crusher 3 is omitted. May be good. Further, in each of the above embodiments, the decarburization device 10 is used to remove the carbonic acid component from the generated gas 110B to improve the efficiency of liquid fuel synthesis, but the decarburization device 10 is not essential.

(4) In the second embodiment, the outlet of the exhaust gas path L17 connected to the gas turbine 14 is connected to the dryer 2, and the turbine exhaust gas 150 discharged from the gas turbine 14 is supplied to the dryer 2. Although the drying heat source of the biomass 100 in the dryer 2 is used, the turbine exhaust gas 150 may be used as a heating source of the steam 50B supplied to the gasifier 4. Specifically, the exhaust gas path L17 may be connected to at least one of the high temperature heat exchanger 5 and the low temperature heat exchanger 7 instead of the dryer 2 or in combination with the dryer 2.

(5) In each of the above embodiments, steam 50B as a gasifying agent is directly supplied to the gasifier 4 from the steam pipe (steam supply line) L52, but the steam 50B is directly supplied to the gasifier 4. It is not limited to the configuration to be supplied. For example, the steam pipe (steam supply line) L52 is connected to the oxygen pipe L53, the steam 50B is supplied into the oxygen pipe L53, and the steam pipe L53 is supplied to the gasifier 4 in a mixed state with the oxygen 50A via the oxygen pipe L53. You may. That is, in the present invention, supplying steam from the steam supply line to the gasification furnace includes supplying steam from the steam supply line to the gasification furnace via another transport path.

(6) In each of the above embodiments, the bypass line (steam mixing line) L52'is connected to the off-gas line L13 so that the steam 50B is mixed into the off-gas 130 of the off-gas line L13. The line) L52'may be directly connected to the SOFC 13 to mix the water vapor 50B into the off-gas 130 supplied to the fuel electrode.

1,1A, 1B Power generation system 2 Dryer 4 Gasifier 11 Liquid fuel synthesizer (fuel synthesizer)
12 Gas-liquid separator 13 Solid oxide fuel cell (SOFC)
13a Air compressor 14 Gas turbine 15 Generator 50 Gasifier 50A Oxygen 50B Water vapor 100, 100A, 100B Biomass resource (biomass)
110, 110A, 110B, 110C Produced gas 120 Hydrocarbon fuel 120A Liquid fuel 130 Off gas 130A Off gas (battery exhaust gas)
140, 140A Air 150 Turbine exhaust gas L14 piping (battery exhaust gas line)
L17 exhaust gas path (turbine exhaust gas line)
L52 steam piping (steam supply line)
L52'Bypass line (water vapor mixing line)
L53 Oxygen piping

Claims (8)

Biomass transport channels that supply biomass resources and
A steam supply line that supplies steam and
A gasification furnace in which the biomass resource is supplied from the biomass transport path and at least the steam is supplied as a gasifying agent from the steam supply line to gasify the biomass resource to generate a produced gas.
A fuel synthesizer that synthesizes fuel using the generated gas, and
An off-gas line that supplies off-gas separated from the fuel,
A solid oxide fuel cell in which the off-gas is supplied from the off-gas line and power is generated using the off-gas.
It is provided with a water vapor mixing line that branches from the water vapor supply line and is connected to the off-gas line or the solid oxide fuel cell to mix a part of the water vapor of the water vapor supply line into the off-gas .
The molar ratio (H ₂ O / C) of the steam to the carbon contained in the biomass resource is a lower limit set from the viewpoint of suppressing a decrease in the amount of hydrogen H ₂ produced, and the inside of the gasification furnace. A power generation system, characterized in that the gasifying agent is supplied so as to fall within a range defined by an upper limit value set from the viewpoint of suppressing a temperature drop in the water vapor . Before liver Le ratio (H 2 _{O /} C) is characterized by supplying said gasifying agent to fall within the range of 1.5 to 4, the power generation system of claim 1. The molar ratio (H ₂ It is equipped with a measuring means for measuring O / C) and an on-off valve interposed in the steam mixing line and controlled based on the measurement result of the measuring means.
The power generation system according to claim 1 or 2, wherein the power generation system is characterized in that. A gas purification device for purifying the produced gas produced by the gasification furnace is provided.
The power generation system according to any one of claims 1 to 3, wherein the fuel synthesizer synthesizes fuel using a product gas refined by the gas refiner. A dryer for drying the biomass resource before supplying it to the gasifier is provided.
The power generation system according to any one of claims 1 to 4 , wherein the battery exhaust gas line for supplying the battery exhaust gas discharged from the solid oxide fuel cell to the dryer is provided. With a gas turbine
With a generator driven by the gas turbine
The power generation system according to any one of claims 1 to 5 , wherein the battery exhaust gas line for supplying the battery exhaust gas discharged from the solid oxide fuel cell to the gas turbine as fuel is provided. A dryer for drying the biomass resource before supplying it to the gasifier is provided.
The power generation system according to claim 6 , further comprising a turbine exhaust gas line that supplies turbine exhaust gas discharged from the gas turbine to the dryer. The power generation system according to any one of claims 1 to 7 , wherein the gasification furnace is a jet bed type gasification furnace.

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