JP7110885B2 - Gasification gas production device and gasification gas production method - Google Patents

Description

The present disclosure relates to a gasification gas production apparatus and a gasification gas production method.

BACKGROUND ART Currently, gasification furnaces are used to produce gasified gas by gasifying raw materials such as coal and biomass with a gasifying agent such as steam. The gasification gas produced in the gasifier contains hydrogen ₍ H2) and carbon monoxide (CO). Gasification gas is used as a starting material for target products such as methanol, dimethyl ether, and methane.

In order to improve the production of the target product, it is necessary to optimize the gasification gas composition (molar ratio of hydrogen and carbon monoxide (H ₂ /CO ratio)). However, the composition of the gasification gas changes depending on the type of raw material, the properties of the raw material, the type of gasifying agent, the temperature of the gasifying furnace, and the amount of gasifying agent relative to the raw material.

Therefore, a technique has been disclosed in which a shift reactor is provided in the latter stage of the gasification furnace and the molar ratio of hydrogen and carbon monoxide in the gasification gas is adjusted in the shift reactor (for example, Patent Document 1 ).

Japanese Patent No. 4898759

With the above shift reactor technology, the proportion of hydrogen in the gasification gas can be increased, but the proportion of carbon monoxide cannot be increased. Therefore, there is a need to develop techniques that can increase the proportion of carbon monoxide in the gasification gas.

In view of such problems, an object of the present disclosure is to provide a gasification gas production apparatus capable of increasing the ratio of carbon monoxide in gasification gas, and a method for producing gasification gas. .

In order to solve the above problems, a gasification gas production apparatus according to an aspect of the present disclosure includes a gasification furnace having a storage tank and a steam supply unit that supplies steam to the storage tank, and a gas supply through a connection pipe. A tar cracking furnace connected to the tar cracking furnace, a hydrogen separation section for separating hydrogen from the gasification gas in which tar is cracked by the tar cracking furnace, and the hydrogen separated by the hydrogen separation section is transferred to the connecting pipe and the tar cracking furnace. and a hydrogen supply unit that supplies either one or both.

In order to solve the above problems, a method for producing a gasified gas according to an aspect of the present disclosure includes a step of gasifying a raw material with water vapor to generate a gasified gas in a gasification furnace; a step of supplying oxygen to a tar cracking furnace connected to the gasification furnace to decompose tar contained in the gasification gas; a step of separating hydrogen from the oxidation-reformed gasification gas; and feeding either one or both of the connecting pipe and the tar cracking furnace.

According to the present disclosure, it is possible to increase the proportion of carbon monoxide in the gasification gas.

It is a figure explaining a gasification gas production apparatus. 4 is a flow chart for explaining the process flow of the method for producing gasification gas. It is a figure explaining the gasification gas production apparatus of a modification.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present disclosure are omitted from the drawings. do.

[Gasified gas production device 100]
FIG. 1 is a diagram illustrating a gasification gas production apparatus 100. As shown in FIG. In FIG. 1, solid line arrows indicate the flow of solids (fluid media, raw materials, and residues) and liquids (water and waste water). Also, in FIG. 1, dashed arrows indicate flows of gases (steam, gasified gas, air, flue gas, carbon dioxide, and hydrogen). Also, in FIG. 1, the dashed-dotted arrows indicate the flow of signals.

As shown in FIG. 1, the gasification gas production apparatus 100 includes a combustion furnace 110, a first pipe 112, a second pipe 114, a cyclone 120, a third pipe 122, heat exchangers 130 and 132, Gasification furnace 140, fourth pipe 146, tar cracking furnace 150, heat exchanger 160, spray tower 170, booster 180, waste water treatment unit 190, carbon dioxide separation unit 200, and carbon dioxide supply It includes a unit 210 , a hydrogen separation unit 220 , a hydrogen supply unit 230 and a control unit 240 .

The gasification gas production apparatus 100 uses a fluidized bed of a fluidized medium to gasify raw materials to produce gasification gas. The raw material is, for example, a solid raw material such as coal (brown coal, etc.) or biomass (wood pellets, etc.). The gasification gas production apparatus 100 is a circulating fluidized bed gasification system. That is, the gasification gas production apparatus 100 circulates the fluid medium as a heat medium through the combustion furnace 110, the second pipe 114, the cyclone 120, the third pipe 122, the gasification furnace 140, and the first pipe 112. The fluid medium is silica sand having a particle size of about 300 μm.

The combustion furnace 110 is cylindrical. The first pipe 112 connects the lower portion of the combustion furnace 110 and a gasification furnace 140, which will be described later. Fuel and a fluid medium are introduced from the gasification furnace 140 into the combustion furnace 110 through the first pipe 112 . The combustion furnace 110 burns the fuel to heat the fluidized medium to 900° C. or higher and 1000° C. or lower. A second pipe 114 connects the upper portion of the combustion furnace 110 and a cyclone 120, which will be described later. The flue gas and the fluid medium heated in the combustion furnace 110 are delivered to the cyclone 120 through the second pipe 114 .

The cyclone 120 separates solid and gas from the mixture of the fluidized medium introduced from the combustion furnace 110 through the second pipe 114 and the flue gas. The flue gas separated by cyclone 120 is directed to heat exchanger 130 .

A heat exchanger 130 (carbon dioxide heating section) is connected to the upper portion of the cyclone 120 . The heat exchanger 130 exchanges heat between the flue gas separated by the cyclone 120 and carbon dioxide separated by the carbon dioxide separator 200, which will be described later. Heat exchanger 130 cools the flue gas and heats the carbon dioxide. The heat exchanger 130 heats the carbon dioxide to a temperature (for example, about 500° C.) substantially equal to that of steam supplied by the steam supply unit 144, which will be described later.

The flue gas cooled by heat exchanger 130 is delivered to heat exchanger 132 . The heat exchanger 132 exchanges heat between the flue gas cooled by the heat exchanger 130 and air. Heat exchanger 132 cools the flue gas and heats the air. Air heated by heat exchanger 132 is supplied to combustion furnace 110 . The flue gas cooled by the heat exchanger 132 is dust-removed by a dust remover (not shown). The combustion exhaust gas from which dust has been removed by the dust remover is denitrified by a denitrifier (not shown). The denitrified flue gas is desulfurized by a desulfurizer (not shown). The desulfurized flue gas is discharged to the outside.

On the other hand, the fluid medium separated by the cyclone 120 is guided to the third pipe 122 . A third pipe 122 connects the bottom of the cyclone 120 and the gasification furnace 140 . Therefore, the high-temperature fluidized medium separated by the cyclone 120 is introduced into the gasification furnace 140 through the third pipe 122 .

The hot fluid medium is fluidized by the gasification agent (steam) in the gasification furnace 140 . Specifically, the gasification furnace 140 includes a storage tank 142 and a steam supply section 144 . The storage tank 142 stores the fluid medium and raw materials.

The steam supply unit 144 supplies steam to the storage tank 142 . The steam supply unit 144 includes a windbox 144a and a boiler 144b. The wind box 144 a is provided below the storage tank 142 . The upper portion of the wind box 144 a also functions as the bottom surface of the storage tank 142 . The upper part of the wind box 144a is composed of a permeable distribution plate. The boiler 144b produces steam. The boiler 144b is connected to the windbox 144a. Steam produced by boiler 144b is supplied to windbox 144a. The water vapor supplied to the wind box 144 a is supplied into the storage tank 142 from the bottom surface (dispersion plate) of the storage tank 142 . The boiler 144b supplies steam to the wind box 144a at a flow rate capable of forming a fluidized bed of fluidized medium in the storage tank 142 . Therefore, the hot fluid medium introduced from the cyclone 120 is fluidized by the steam. As a result, a fluidized bed of the fluidized medium (for example, a bubble fluidized bed (bubbling fluidized bed)) is formed in the storage tank 142 .

Also, raw materials are introduced into the gasification furnace 140 (accommodation tank 142). The introduced raw material is gasified (steam gasification) by heat of 700° C. to 900° C. and steam possessed by the fluid medium, thereby producing a gasification gas (synthesis gas). Gasification gas produced in the gasification furnace 140 is introduced into the tar decomposition furnace 150 through the fourth pipe 146 . A fourth pipe 146 (connection pipe) connects the upper portion of the gasification furnace 140 and the tar decomposition furnace 150 .

On the other hand, as described above, the fluidized medium fluidized in the gasification furnace 140 is returned to the combustion furnace 110 through the first pipe 112 connecting the gasification furnace 140 and the combustion furnace 110 .

As described above, in the gasification gas production apparatus 100 according to the present embodiment, the fluid medium flows through the combustion furnace 110, the second pipe 114, the cyclone 120, the third pipe 122, the gasification furnace 140, and the first pipe 112. These are circulated by moving in order and being introduced into the combustion furnace 110 again.

Further, the residue of the raw material is introduced from the gasification furnace 140 into the combustion furnace 110 through the first pipe 112 . The raw material residue is utilized as fuel in the combustion furnace 110 . The raw material residue is the raw material that remains without being gasified in the gasification furnace 140 .

The tar cracking furnace 150 (oxidative reforming furnace) adds oxygen or air to the gasification gas generated in the gasification furnace 140 and burns part of the gasification gas. Then, the gasification gas becomes about 900.degree. C. to 1500.degree. As a result, the tar contained in the gasification gas is oxidatively reformed (decomposed).

The heat exchanger 160 exchanges heat between the gasified gas in which tar is decomposed by the tar cracking furnace 150 and steam. The heat exchanger 160 recovers the sensible heat of the gasification gas with water vapor, and sets the outlet temperature of the gasification gas to 300°C or higher and 600°C or lower.

The spray tower 170 sprays water at about 40° C. to the gasification gas. Thereby, the gasification gas is cooled to about 70°C. Dust (sludge) remaining in the gasification gas is then condensed and removed from the gasification gas.

The booster 180 is composed of, for example, a blower, a compressor, a turbo pump, or a positive displacement pump. The booster 180 pressurizes the gasified gas from which the sludge has been removed by the spray tower 170 to 0.1 MPa to 5 MPa.

The wastewater treatment section 190 purifies wastewater generated in the spray tower 170 and the booster 180 . The wastewater treatment unit 190 includes a tar decanter, a raw water tank, a coagulating sedimentation tank, a septic tank, and the like. A tar decanter temporarily stores waste water. The tar decanter separates wastewater into supernatant and sediment due to differences in specific gravity (mass weight and particle size). The supernatant contains tar. Sediment includes dust. The supernatant produced in the tar decanter is sent to the raw water tank. Sediment generated in the tar decanter is discarded after being subjected to a predetermined treatment. The raw water tank temporarily stores the supernatant liquid separated by the tar decanter and the waste water generated in the booster 180 . Wastewater (including supernatant liquid) is introduced from the raw water tank to the coagulating sedimentation tank. A coagulating sedimentation tank mixes waste water and a coagulant. As a result, the inorganic ions in the wastewater are aggregated and removed from the wastewater. Drainage from the coagulating sedimentation tank is led to the septic tank. Septic tanks remove ammonia and organic matter in wastewater. Thus treated waste water is discharged.

The carbon dioxide separation unit (shown as “CO2 separation unit” in FIG. 1) 200 is, for example, a device using a physical absorption method or a device using a chemical absorption method. The carbon dioxide separation unit 200 separates carbon dioxide from the gasification gas produced in the gasification furnace 140 .

The carbon dioxide supply unit 210 includes a fifth pipe 212, a pump 214, a sixth pipe 216, a seventh pipe 216a, a flow control valve 216b, and an eighth pipe 218. A fifth pipe 212 connects the carbon dioxide separator 200 and the suction side of the pump 214 . A sixth pipe 216 connects the discharge side of the pump 214 and the heat exchanger 130 . The seventh pipe 216 a branches off from the sixth pipe 216 . The flow control valve 216 b is provided in the sixth pipe 216 between the branch point of the seventh pipe 216 a and the heat exchanger 130 . The eighth pipe 218 connects the heat exchanger 130 and the wind box 144 a of the gasification furnace 140 .

Pump 214 guides the carbon dioxide separated from the gasification gas by carbon dioxide separation section 200 to heat exchanger 130 . Then, the carbon dioxide separated from the gasification gas by the carbon dioxide separation section 200 is heated in the heat exchanger 130 . The carbon dioxide heated by the heat exchanger 130 is supplied through the eighth pipe 218 to the wind box 144a of the gasification furnace 140 . The carbon dioxide supplied to the wind box 144a is supplied to the storage tank 142 together with water vapor.

On the other hand, the carbon dioxide that has passed through the seventh pipe 216a is sent to the subsequent carbon dioxide treatment facility.

The hydrogen separation unit (shown as “H2 separation unit” in FIG. 1) 220 is, for example, a device using a PSA (Pressure Swing Adsorption) method or a device including a hydrogen separation membrane. The hydrogen separation unit 220 separates part of hydrogen from the gasified gas from which carbon dioxide has been separated by the carbon dioxide separation unit 200 . The gasification gas from which a portion of the hydrogen has been removed by the hydrogen separation unit 220 is sent to the subsequent product manufacturing facility as a refined gasification gas.

The hydrogen supply unit 230 includes a ninth pipe 232, a pump 234, a tenth pipe 236, an eleventh pipe 236a, and a flow control valve 236b. The ninth pipe 232 connects the hydrogen separating section 220 and the suction side of the pump 234 . A tenth pipe 236 connects the discharge side of the pump 234 and the fourth pipe 146 . The eleventh pipe 236 a branches off from the tenth pipe 236 . The flow control valve 236 b is provided in the tenth pipe 236 between the branch point of the eleventh pipe 236 a and the fourth pipe 146 .

The pump 234 guides the hydrogen separated from the gasified gas by the hydrogen separating section 220 to the fourth pipe 146 . On the other hand, the hydrogen that has passed through the eleventh pipe 236a joins the refined gasification gas.

The control unit 240 is composed of a semiconductor integrated circuit including a CPU (Central Processing Unit). The control unit 240 reads programs, parameters, and the like for operating the CPU itself from the ROM. The control unit 240 manages and controls the entire gasification gas production apparatus 100 in cooperation with a RAM as a work area and other electronic circuits.

In this embodiment, the control unit 240 determines that the composition of the refined gasification gas (molar ratio of hydrogen and carbon monoxide (H ₂ /CO ratio)) is optimal as a starting material for the target product manufactured in the product manufacturing facility. The opening degrees of the flow control valve 216b and the flow control valve 236b are controlled so that the composition is uniform.

[Method for producing gasification gas]
Next, a method for producing gasified gas using the gasified gas producing apparatus 100 will be described. FIG. 2 is a flow chart for explaining the process flow of the method for producing gasification gas. As shown in FIG. 2, the gasification gas production method includes a gasification step S110, a decomposition step S120, a first separation step S130, a first supply step S140, a second separation step S150, a second supply and step S160. Each step will be described in detail below.

[Gasification step S110]
The gasification step S110 is a step of gasifying the raw material with water vapor in the gasification furnace 140 to generate a gasification gas.

[Decomposition step S120]
The decomposition step S120 is a step of supplying oxygen to the tar decomposition furnace 150 connected to the gasification furnace 140 via the fourth pipe 146 to decompose the tar contained in the gasification gas.

[First separation step S130]
The first separation step S130 is a step in which the carbon dioxide separation unit 200 separates carbon dioxide from the gasified gas in which the tar is decomposed in the decomposition step S120.

[First supply step S140]
The first supply step S140 is a step in which the carbon dioxide supply unit 210 supplies the carbon dioxide separated in the first separation step S130 to the gasification furnace 140 .

At this time, the control unit 240 adjusts the opening degree of the flow control valve 216b so that the composition of the refined gasification gas becomes the optimum composition as the starting material for the target product manufactured by the product manufacturing facility.

[Second separation step S150]
The second separation step S150 is a step in which the hydrogen separation unit 220 separates hydrogen from the gasified gas from which carbon dioxide has been separated in the first separation step S130.

[Second supply step S160]
The second supply step S<b>160 is a step in which the hydrogen supply unit 230 supplies the hydrogen separated in the second separation step S<b>150 to the fourth pipe 146 .

At this time, the control unit 240 adjusts the opening degree of the flow control valve 236b so that the composition of the refined gasification gas becomes the optimum composition as the starting material for the target product manufactured by the product manufacturing facility.

As described above, the gasification gas production apparatus 100 and the gasification gas production method using the same according to the present embodiment are provided with the carbon dioxide separator 200 and the carbon dioxide supply section 210 . Therefore, in the gasification furnace 140, the reaction represented by the following reaction formula (1) can proceed.
C + CO ₂ → 2CO ... reaction formula (1)
This makes it possible to increase the amount of carbon monoxide (CO) in the gasification gas produced in the gasification furnace 140 . Therefore, the composition of the refined gasification gas can be optimized as the starting material for the target product. Therefore, it is possible to improve the production volume of the target product. For example, when the target product is methanol, the optimal composition is hydrogen:carbon monoxide=2.05:1. When the target product is dimethyl ether (DME), the optimal composition is hydrogen:carbon monoxide=2:1. When the target product is methane, the optimum composition is hydrogen:carbon monoxide=3:1.

In addition, the gasification gas production apparatus 100 can convert carbon dioxide into carbon monoxide and fix it in the target product. That is, the gasification gas production apparatus 100 can reduce the amount of carbon dioxide emitted (the amount emitted to the atmosphere).

The gasification gas production apparatus 100 also includes a heat exchanger 130 , and the carbon dioxide supply unit 210 supplies carbon dioxide heated by the heat exchanger 130 to the gasification furnace 140 . Therefore, the reaction represented by the reaction formula (1) can proceed without lowering the temperature of the gasification furnace 140 . Therefore, it becomes possible to efficiently convert the raw material (C (carbon)) into carbon monoxide.

In addition, the gasification gas production apparatus 100 heats (preheats) carbon dioxide with the heat of the flue gas generated in the combustion furnace 110 . Therefore, the gasification gas production apparatus 100 can omit a heater dedicated to heating carbon dioxide. Therefore, it is possible to reduce the cost required for the heater and the operating cost (energy consumption) of the heater.

Also, the carbon dioxide supply unit 210 supplies carbon dioxide to the wind box 144a. Therefore, the carbon dioxide supply unit 210 can supply carbon dioxide evenly (uniformly) to the storage tank 142 . Therefore, it is possible to avoid a situation in which the reaction represented by the reaction formula (1) occurs locally. As a result, it is possible to efficiently convert the raw material (C (carbon)) into carbon monoxide and to gasify the water vapor.

The gasification gas production apparatus 100 and the gasification gas production method using the same also include a hydrogen separating section 220 and a hydrogen supply section 230 . Therefore, the hydrogen concentration in the gasification gas introduced into the tar cracking furnace 150 can be increased. Therefore, in the tar cracking furnace 150, it is possible to preferentially oxidize (burn) hydrogen over carbon monoxide. This makes it possible to increase the amount of carbon monoxide (CO) in the gasification gas delivered from the tar cracking furnace 150 . Therefore, the composition of the refined gasification gas can be optimized as the starting material for the target product. Therefore, it is possible to improve the production volume of the target product.

[Modification]
The gasification gas production apparatus 100 of the above embodiment has been described with an example of a configuration in which the hydrogen supply unit 230 supplies hydrogen to the fourth pipe 146 . However, as long as hydrogen can be supplied to the tar cracking furnace 150, the configuration is not limited.

FIG. 3 is a diagram illustrating a gasification gas production apparatus 300 of a modified example. In FIG. 3, the solid arrows indicate the flow of solids (fluid medium, raw materials, and residue) and liquids (water and waste water). Also, in FIG. 3, dashed arrows indicate flows of gases (steam, gasified gas, air, flue gas, carbon dioxide, and hydrogen). Also, in FIG. 3, the dashed-dotted arrows indicate the flow of signals.

Constituent elements that are substantially the same as those of the gasification gas production apparatus 100 are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIG. 3 , the gasification gas production device 300 includes a hydrogen supply section 330 . The hydrogen supply unit 330 includes a ninth pipe 232, a pump 234, a twelfth pipe 336, a thirteenth pipe 336a, and a flow control valve 336b.

A twelfth pipe 336 connects the discharge side of the pump 234 and the tar cracking furnace 150 . The thirteenth pipe 336 a branches off from the twelfth pipe 336 . The flow control valve 336 b is provided in the twelfth pipe 336 between the branch point of the thirteenth pipe 336 a and the tar cracking furnace 150 .

The modified gasification gas production apparatus 300 includes a hydrogen supply section 330 . Therefore, the hydrogen concentration in the tar cracking furnace 150 can be increased. Therefore, in the tar cracking furnace 150, it is possible to preferentially oxidize (burn) hydrogen over carbon monoxide. This makes it possible to increase the amount of carbon monoxide (CO) in the gasification gas delivered from the tar cracking furnace 150 .

Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above embodiments. It is clear that a person skilled in the art can conceive of various modifications or modifications within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. be done.

For example, in the above-described embodiments and modifications, the gasification gas production apparatuses 100 and 300 have been described with the configuration including the carbon dioxide separation section 200 and the carbon dioxide supply section 210 as an example. However, the carbon dioxide separating section 200 and the carbon dioxide supplying section 210 are not essential components.

Further, in the above embodiment, the heat exchanger 130 that exchanges heat with the combustion exhaust gas has been described as an example of the carbon dioxide heating unit. However, as long as the carbon dioxide heating unit can heat the carbon dioxide separated by the carbon dioxide separation unit 200 and supplied to the gasification furnace 140, the heat source is not limited. That is, the combustion furnace 110 and the cyclone 120 are not essential components. The carbon dioxide heating unit may be, for example, a heat exchanger that exchanges heat between other flue gas and carbon dioxide, or an electric heater.

Further, in the above-described embodiment, the configuration in which the gasification furnace 140 includes the storage tank 142 and the wind box 144a has been described as an example. However, the gasification furnace 140 is not limited in its configuration as long as the raw material and steam are introduced, the raw material is steam-gasified, and the gasified gas can be generated. For example, the gasifier 140 may include a containment vessel 142 and an air diffuser. In this case, the diffuser pipe is placed inside the storage tank 142 . Also, the diffuser pipe supplies water vapor to the storage tank 142 . Then, the carbon dioxide supply unit 210 may supply carbon dioxide to the air diffuser.

Further, in the above embodiment, the gasification furnace 140 has been described by exemplifying the configuration in which the solid raw material is gasified in the fluidized bed of the fluidized medium. However, the gasification furnace 140 only needs to be able to vaporize the solid raw material with the heat of the fluid medium. Gasifier 140 may, for example, gasify solid feedstock in a moving bed of fluidized medium.

Further, in the above-described embodiment and modifications, the configuration in which the carbon dioxide supply unit 210 supplies carbon dioxide to the wind box 144a has been described as an example. However, the carbon dioxide supply unit 210 only needs to supply carbon dioxide to the gasification furnace 140 .

The gasification gas production apparatuses 100 and 300 may also include a hydrogen heating section that heats the hydrogen separated by the hydrogen separation section 220 . The hydrogen heating unit may be, for example, a heat exchanger that exchanges heat between the flue gas separated by the cyclone 120 and hydrogen, or an electric heater.

INDUSTRIAL APPLICABILITY The present disclosure can be used for a gasification gas production apparatus and a gasification gas production method.

100 gasification gas production device 146 fourth pipe (connecting pipe)
150 Tar cracking furnace 220 Hydrogen separator 230 Hydrogen supply unit 300 Gasification gas production device 330 Hydrogen supply unit

Claims (2)

a gasification furnace having a storage tank and a steam supply section for supplying steam to the storage tank;
a tar cracking furnace connected to the gasification furnace via a connecting pipe;
a hydrogen separation unit for separating hydrogen from the gasification gas in which tar is decomposed by the tar decomposition furnace;
a hydrogen supply unit that supplies the hydrogen separated by the hydrogen separation unit to one or both of the connecting pipe and the tar cracking furnace;
A gasification gas production device comprising: a step of gasifying a raw material with water vapor in a gasification furnace to generate a gasification gas;
supplying oxygen to a tar decomposition furnace connected to the gasification furnace through a connecting pipe to decompose tar contained in the gasification gas;
separating hydrogen from the oxidatively reformed gasification gas;
a step of supplying the separated hydrogen to one or both of the connecting pipe and the tar cracking furnace;
A method for producing a gasification gas comprising:

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