CN110475844A - Gas is modified furnace - Google Patents

Abstract

The invention provides a gas reforming furnace. In the gas reforming furnace (1), a furnace main body (11) is formed with a flow path (100) through which pyrolysis gas supplied from a gasification furnace (81) flows. The filled layer holding part (2) is provided in the flow channel (100), and holds the charred material filled layer (22) filled with the charred material. The tar burner (3) supplies oxygen-containing gas to the pyrolysis gas in a space upstream of the char-filled layer (22) in the flow channel (100), so that the pyrolysis gas passes through the char-filled layer. (22) Burn the tar contained in the pyrolysis gas beforehand. The water vapor ejection unit (4) ejects water vapor from an ejection port provided inside the charred material filling bed (22). Thereby, the density|concentration of the tar contained in pyrolysis gas can be reduced significantly.

Description

Gas modification furnace

technical field

The invention relates to a gas reforming furnace.

Background technique

Conventionally, gasification of carbonaceous raw materials such as biomass has been performed. In the gasification of the raw material, the raw material is thermally decomposed in a gasification furnace at 500 to 800° C. to generate pyrolysis gas. The pyrolysis gas includes not only gas but also vapor of tar, char of powder, and the like. The pyrolysis gas is sent to the subsequent gas reforming furnace. Inside the gas reforming furnace, a high temperature state of 1000° C. or higher is maintained by partial combustion by oxygen supply, heating of high-temperature gas, or heating of a heater, and steam is blown in. As a result, tar and charred substances in the pyrolysis gas are reformed by water vapor and converted into fuel gases such as hydrogen (H ₂ ) and carbon monoxide (CO). The reformed pyrolysis gas is used for power generation in an internal combustion engine such as a gas engine after impurities and the like are removed in a gas purification unit.

In addition, Japanese Patent Laid-Open Publication No. 2007-177106 discloses a biomass gasification device. The gasification part of the device includes: a first retention part temporarily retains the charred matter flowing down from the thermal decomposition part and guides the charred matter downward; a first oxidizing gas supply part communicates with the first retention part An oxidizing gas such as air is introduced into the flow-down passage; the second retention part temporarily retains the burnt matter flowing down from the flow-down passage; the gas extraction port is formed at the upper end of the second retention part; An oxidizing gas such as air is introduced into the retention unit. In the device, pyrolysis gas containing tar components passes through the downflow channel and flows toward the gas extraction port. The burnt material and the pyrolysis gas are combusted by the air supplied from the first oxidizing gas supply unit, thereby raising the temperature of the flow-down passage. Thus, the tar component in the pyrolysis gas is thermally decomposed and gasified. On the other hand, the burnt matter flowing down to the second stagnation part is subjected to a combustion reaction by the air supplied from the second oxidizing gas supply part, and a combustion gas mainly composed of carbon dioxide and water vapor is generated. When the combustion gas rises toward the gas outlet, it reacts with the charred material to generate carbon monoxide and hydrogen.

In addition, in Japanese Patent Laid-Open Publication No. 2007-231063, a gasification device is disclosed. In a fixed-bed gasification furnace with a packed bed of charred material deposited at the bottom, the pyrolysis gas is passed through the packed bed of charred material. , so as to carry out the gasification of char and the decomposition of tar. In addition, air nozzles for jetting compressed air into the charred-filled bed are provided, and the air nozzles are controlled according to the temperature upstream of the charred-filled bed and the temperature downstream of the charred-filled bed, thereby preventing the Ventilation occurs in the char pack.

However, in the above method of blowing only oxygen and water vapor into the gas reforming furnace, tar in the pyrolysis gas may not be sufficiently decomposed. At this time, due to the influence of the residual tar, there is a risk that the process in the gas refining unit and the power generation in the gas engine will fail. Therefore, a method for significantly reducing the concentration of tar contained in pyrolysis gas has been desired.

Contents of the invention

The present invention relates to a gas reforming furnace for reforming pyrolysis gas supplied from a gasification furnace, and aims to significantly reduce the concentration of tar contained in the pyrolysis gas.

The gas reforming furnace of the present invention includes: a furnace main body forming a flow channel through which pyrolysis gas flows; a filling layer holding part arranged in the flow channel to hold a char filling layer filled with char; a tar burning part, By supplying an oxygen-containing gas to the pyrolysis gas in a space on the upstream side of the charred material-filled bed in the flow channel, the pyrolysis gas is used before the pyrolysis gas passes through the charred material-filled bed. tar contained in the pyrolysis gas is combusted; and a water vapor ejection unit ejects water vapor from an ejection port provided inside or near the charred matter filled bed.

According to the present invention, the concentration of tar contained in pyrolysis gas can be significantly reduced.

In a preferred aspect of the present invention, the filled layer holding unit has a holding member formed with a plurality of holes and holds the charred material filled layer from below.

In another preferred aspect of the present invention, the gas reforming furnace further includes: a charred material supply unit that supplies the charred material to the filled layer holding unit; a layer thickness acquisition unit that acquires the thickness of the charred material filled layer; and a control unit that controls a supply amount of the charred material supplied from the charred material supply unit based on the thickness.

In another preferred aspect of the present invention, in the flow direction of the pyrolysis gas, the length of the tar burning part from the supply position of the oxygen-containing gas to the surface of the charred material filled layer is, greater than the thickness of the char-filled layer.

In another preferred aspect of the present invention, the temperature of a space on the downstream side of the charred material filled layer in the flow channel is lower than the temperature in the charred material filled layer.

The above and other objects, features, modes and advantages will be more clearly understood from the following detailed description of the present invention with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a diagram showing the configuration of a gasification system.

FIG. 2 is a diagram showing the configuration of a steam ejection unit.

FIG. 3 is a diagram showing the configuration of a water vapor ejection unit.

Fig. 4 is a diagram showing the configuration of an experimental device.

FIG. 5 is a graph showing experimental results.

Fig. 6 is a diagram showing another example of a water vapor ejection unit.

Fig. 7 is a diagram showing another example of a steam ejection unit.

Fig. 8 is a diagram showing another example of a steam ejection unit.

Explanation of reference signs

1 Gas modification furnace

2 Filling layer holding part

3 Tar combustion department

4 Water vapor ejection part

10 Control Department

11 Furnace body

21 holding member

22 Charred Fill Layers

51 Charred material supply department

52 Layer thickness acquisition department

81 Gasifier

100 runners

101 Upstream side space

102 Downstream side space

411 Discharge port

Detailed ways

FIG. 1 is a diagram showing the configuration of a gasification system 8 according to one embodiment of the present invention. The gasification system 8 includes a gasification furnace 81 , a gas reforming furnace 1 , a boiler 82 , a gas refining unit 83 , an induced draft fan 84 , a gas engine 85 , and a chimney 86 . In the gasification system 8 , there is formed an overall flow passage passing through the gasification furnace 81 , the gas reforming furnace 1 , the boiler 82 , the gas refining unit 83 , the induced draft fan 84 , the gas engine 85 and the chimney 86 in sequence. By driving the induced draft fan 84 , pyrolysis gas, which will be described later, generated in the gasification furnace 81 flows toward the chimney 86 through the overall flow path.

The gasifier 81 is, for example, a kiln gasifier, a fixed-bed gasifier, a fluidized-bed gasifier, or the like. Waste or biomass (hereinafter simply referred to as "raw material") is charged into the gasification furnace 81 . The raw materials are, for example, general waste, industrial waste, sludge, woody biomass, and the like. For example, the raw material is heated at 400 to 800° C. to thermally decompose and vaporize the raw material. As a result, pyrolysis gas is generated. The pyrolysis gas includes not only gas but also tar vapor, charred powder, and the like. The pyrolysis gas is supplied to the gas reforming furnace 1 . At the bottom of the gasification furnace 81, a charred matter recovery unit (not shown) for recovering charred matter not included in the pyrolysis gas is provided. The recovered charred matter (hereinafter referred to as “recovered charred matter”) is supplied into the furnace main body 11 of the gas reforming furnace 1 by a screw feeder 511 described later.

In the gas reforming furnace 1 , carbon-containing non-gas components such as tar and burnt matter contained in the pyrolysis gas are reformed and the like. The structure of the gas reforming furnace 1 will be described later. The pyrolysis gas reformed by the gas reforming furnace 1 (hereinafter referred to as “reformed gas”) flows into the boiler 82 . In the boiler 82, the reformed gas exchanges heat with the circulating water flowing through the boiler 82, thereby reducing the temperature of the reformed gas. The reformed gas flows from the boiler 82 into the gas refining unit 83 . In the gas refining unit 83, refining processes such as removal of dust and water vapor, desalination, and desulfurization are performed on the reformed gas. The refined reformed gas is, for example, about 50° C., and is supplied to the gas engine 85 via the induced draft fan 84 . In the gas engine 85, the reformed gas is used as fuel to generate electricity. Exhaust gas obtained by combusting the reformed gas in the gas engine 85 is discharged to the atmosphere through a chimney 86 .

The circulating water in the boiler 82 turns into water vapor by exchanging heat with reformed gas. Part of the steam is supplied to a steam ejection unit 4 described later in the gas reforming furnace 1 . The remaining steam is used to drive the steam turbine 821 and then returns to the inside of the boiler 82 as circulating water. The aforementioned water vapor may also be supplied to the gasification furnace 81 and used for heating the raw material.

The gas reforming furnace 1 includes a furnace main body 11 , a packed bed holding unit 2 , a char supply unit 51 , a layer thickness acquisition unit 52 , a tar combustion unit 3 , a steam ejection unit 4 , and a control unit 10 . The control unit 10 is in charge of overall control of the gas reforming furnace 1 . The control unit 10 may also be in charge of overall control of the gasification system 8 .

The furnace main body 11 is, for example, substantially cylindrical. One end of the furnace main body 11 is provided with an inflow port 111 connected to the gasification furnace 81 . The other end of the furnace main body 11 is provided with an outlet 112 connected to the boiler 82 . The pyrolysis gas from the gasification furnace 81 flows into the interior of the furnace main body 11 through the inflow port 111 . The pyrolysis gas flows toward the outflow port 112 inside the furnace main body 11 , and flows out to the boiler 82 through the outflow port 112 . Thereby, the flow path 100 through which the pyrolysis gas flows is formed in the furnace main body 11 . The shape of the furnace main body 11 can be appropriately changed, for example, it may be U-shaped or the like.

The filled layer holding unit 2 has a plate-shaped holding member 21 provided in the flow channel 100 . The holding member 21 extends substantially vertically with respect to the flow direction of the pyrolysis gas from the inlet 111 to the outlet 112 (hereinafter referred to as “gas flow direction”), and is connected to the entire circumference of the side wall of the furnace body 11 . In this embodiment, the gas flow direction is parallel to the vertical direction. A plurality of holes through which the pyrolysis gas passes is uniformly dispersed and formed in the holding member 21 . The holding member 21 is formed of, for example, ceramics, porcelain, refractory material, concrete, metal, or the like. Burnt matter is deposited on the holding member 21 . In other words, the char-filled layer 22 filled with char is provided on the holding member 21 . The char-filled layer 22 spreads over the entire upper surface of the holding member 21 . The charred material filled layer 22 is held by the holding member 21 from below.

The charred material supply unit 51 has a screw feeder 511 . One end of the screw feeder 511 is connected to the charred material recovery part of the gasification furnace 81 . The other end of the screw feeder 511 is connected to the furnace main body 11 of the gas reforming furnace 1 . In the furnace main body 11 , a charred material supply port 113 is provided between the packed bed holding portion 2 and the inflow port 111 . The recovered charred material is conveyed from the charred material recovery unit to the charred material supply port 113 by driving the screw feeder 511 , and supplied to the packed bed holding unit 2 . In the gas reforming furnace 1 , by controlling the screw feeder 511 by the control unit 10 , the supply amount of the recovered charred matter (the conveying speed of the recovered charred matter) is adjusted. In the charred material supply part 51, besides the screw feeder 511, a powder supply machine such as a table top feeder may be provided, and the recovered charred material may be supplied to the packed bed holding part 2 via a chute. In addition, depending on the structure of the gasification furnace 81 and the gas reforming furnace 1, the bottom of the gasification furnace 81 may be connected to the upper part of the furnace main body 11, and only the collected charred matter may be dropped from the bottom so that it can be injected into the filling bed. The holding unit 2 supplies and collects burnt matter. At this time, for example, a mechanism (such as a gate) for adjusting the falling amount of recovered charred material from the bottom of the gasification furnace 81 may be provided.

The layer thickness acquisition unit 52 has a level sensor 521 . The level sensor 521 is a laser type, and detects the height of the surface (upper surface in FIG. 1 ) of the charred material filled layer 22 . The detection value of the material level sensor 521 is output to the control part 10. Actually, by detecting the height of the surface of the charred matter filled layer 22, the distance between the holding member 21 of the packed layer holding part 2 and the surface of the charred matter filled layer 22, that is, the thickness of the charred matter filled layer 22 is obtained. (hereinafter referred to as "layer thickness"). The control unit 10 controls the supply amount of the recovered charred material supplied from the charred material supply unit 51 to the packed bed holding unit 2 based on the obtained layer thickness. Actually, the supply amount of recovered burnt material is controlled so that the layer thickness is maintained at a constant value.

As described above, the charred material supply part 51 replenishes and collects the charred material to the charred material filled layer 22 by extruding the charred material from the charred material supply port 113, so that the surface of the charred material filled layer 22 is undulated, but In this processing example, since the layer thickness is not strictly required, no problem arises. Of course, by providing a plurality of level sensors 521 and obtaining the average value of the detection values of the plurality of level sensors 521, the layer thickness can also be obtained with high accuracy. In the layer thickness acquiring unit 52, the difference between the pressure at the upstream side of the charred material filled layer 22 and the pressure at the downstream side of the charred material filled layer 22 can also be obtained. layer thickness.

When the amount of charred material generated in the gasification furnace 81 is excessively larger than the supply amount of recovered charred material supplied from the charred material supply unit 51 to the packed bed holding unit 2, it is possible to use a gate (not shown) or the like. Charred materials are discharged to the outside for recovery. At this time, the gasification efficiency of the raw material can be improved by putting the recovered charred material discharged to the outside into the gasification furnace 81 again. On the other hand, when the amount of charred material generated in the gasification furnace 81 is smaller than the amount to be supplied to the packed bed holding unit 2 , charcoal, coal, activated carbon, etc. may be auxiliary supplied to the packed bed holding unit 2 . In addition, the ratio of the charred material generated from the raw material depends on the heating temperature in the gasifier 81 . For example, in one example of the kiln-type gasifier 81, when the heating temperature is 400°C, the proportion of charred matter generated from raw materials is about 50%, and when the heating temperature is 600°C, the proportion of charred matter is About 30%. Accordingly, as the heating temperature in the gasification furnace 81 increases, the ratio of charred matter generated from the raw material decreases.

The tar burning unit 3 includes a plurality of oxidizing gas nozzles 31 and an oxidizing gas supply unit 32 . A plurality of oxidizing gas nozzles 31 are arranged in the space 101 on the upstream side of the charred material filled layer 22 in the flow channel 100 (the space on the inflow port 111 side of the charred material filled layer 22 is hereinafter referred to as "upstream side". Space 101"). The oxidizing gas supply unit 32 supplies an oxygen-containing gas (hereinafter referred to as “oxidizing gas”) to the oxidizing gas nozzle 31 . The oxidizing gas is, for example, air. The oxidizing gas may also be oxygen itself. The oxidizing gas from the oxidizing gas supply unit 32 is sprayed from the plurality of oxidizing gas nozzles 31 into the upstream space 101 . In the tar burner 3 , oxidizing gas nozzles 31 may be provided in multiple stages along the gas flow direction on the side wall of the furnace main body 11 . In addition, the oxidizing gas nozzle 31 may be provided on the upper surface of the furnace main body 11 .

FIG. 2 and FIG. 3 are diagrams showing the configuration of the steam ejection unit 4 . FIG. 2 shows a section of the furnace body 11 perpendicular to the gas flow direction at the position of the steam pipe 41 described later (the section viewed from the inlet 111 side), and FIG. 3 shows a cross section parallel to the gas flow direction. The section of the furnace main body 11. The steam ejection unit 4 has a steam pipe 41 through which steam supplied from a boiler 82 flows. The steam pipe 41 has a plurality of folded portions that are bent in a U shape on a surface perpendicular to the gas flow direction. A plurality of folded portions are arranged inside the furnace main body 11 , more specifically, inside the charred material filled bed 22 . A plurality of discharge ports 411 are provided in a portion of the steam pipe 41 disposed inside the furnace main body 11 . In the example of FIG. 3 , the plurality of discharge ports 411 open toward the side opposite to the holding member 21 , that is, open toward the upstream side space 101 side. The water vapor ejection unit 4 ejects water vapor from a plurality of ejection ports 411 . The temperature of water vapor is, for example, about 300°C. In FIG. 3 , the direction in which water vapor is ejected from each ejection port 411 is indicated by an arrow marked with reference sign A1.

The length of the portion of the steam pipe 41 disposed inside the furnace body 11 is preferably at least the diameter of the furnace body 11 , more preferably at least twice the diameter of the furnace body 11 . As a result, water vapor can be easily dispersed and sprayed over a wide range on a surface perpendicular to the gas flow direction. The length of the portion is, for example, 10 times or less the diameter of the furnace main body 11 . The plurality of ejection ports 411 may open toward the holding member 21 side. The water vapor to be supplied to the water vapor pipe 41 can be generated using the heat of the exhaust gas of the gas engine 85 or an external heat source.

In the gas reforming furnace 1 shown in FIG. 1 , the pyrolysis gas supplied from the inflow port 111 to the inside of the furnace main body 11 (flow path 100 ) flows into the charred material filled bed 22 in the upstream space 101 . In the upstream side space 101 , an oxidizing gas is supplied to the pyrolysis gas by a plurality of oxidizing gas nozzles 31 to combust not only the gas generation portion contained in the pyrolysis gas but also the vapor generation portion of tar. A high temperature state is maintained in the upstream side space 101 by continuous partial combustion of the pyrolysis gas, for example, the temperature of the upstream side space 101 reaches 800 to 1200°C. Thereby, in the tar combustion part 3, before the pyrolysis gas reaches the charred material filling layer 22, the tar contained in the pyrolysis gas burns, and the density|concentration of a tar falls. In the tar combustion unit 3, other reactions may occur besides the combustion reaction.

From the viewpoint of securing a sufficient space required for tar combustion, it is preferable in the direction of gas flow, from the supply position of the oxidizing gas (here, the oxidizing gas nozzle 31 farthest from the charred material filled layer 22) to the charred material filling position. The length of the tar burning portion 3 up to the surface of the layer 22 is greater than the thickness of the charred material filled layer 22 . Here, the position of the surface of the char-filled layer 22 is, for example, an averaged position of the surface. More preferably, the length of the tar burning portion 3 is at least 1.5 times the thickness of the charred material filled layer 22 . The length of the tar burning part 3 is, for example, 10 times or less the thickness of the charred material filled layer 22 . Depending on the design of the gas reforming furnace 1 , the length of the tar burning portion 3 may also be less than the thickness of the char-filled layer 22 .

The pyrolysis gas reaching the charred material filled layer 22 flows toward the channel 100 closer to the charred material filled layer 22 through the gap between the recovered charred material in the charred material filled layer 22 and the hole of the holding member 21 . The space 102 on the downstream side (the space on the side of the outflow port 112 from the charred material filled bed 22, hereinafter simply referred to as "the space 102 on the downstream side"). When the pyrolysis gas passes through the charred material filling layer 22 , the tar and powdery charred material remaining in the pyrolysis gas are trapped (collected) by the pores of the charred material filling layer 22 for recovering the charred material. Furthermore, by combustion of the pyrolysis gas in the upstream side space 101 , the charred matter filled layer 22 and the pyrolysis gas flowing through the charred matter filled layer 22 reach a high temperature. And, the recovered charred matter from the plurality of ejection ports 411 (refer to FIG. 2 ) of the steam ejection unit 4 to the charred matter filled layer 22 is strongly ejected (for example, at a flow rate faster than that of the pyrolysis gas). water vapor. As a result, the tar and powdery charred matter captured by the recovered charred matter, and the recovered charred matter itself are converted (reformed) into fuel gases such as hydrogen and carbon monoxide by a steam reforming reaction. In the charred material filled layer 22 , it can also be considered that the modification reaction of tar is promoted by the recovered charred material, that is, the recovered charred material functions as a catalyst.

The reformed pyrolysis gas, that is, the reformed gas reaches the outflow port 112 through the downstream space 102 and is discharged to the boiler 82 . Typically, no oxidizing gas is supplied to the charred material filled layer 22 and the downstream side space 102, and no combustion reaction occurs. In addition, the water vapor modification reaction of tar and the like is an endothermic reaction. Therefore, the temperature in the downstream space 102 is, for example, less than 1200° C., which is lower than the temperatures in the upstream space 101 and the charred material filled layer 22 .

In the charred material filled layer 22 , if the recovered charred material decreases due to modification, new recovered charred material is replenished from the charred material supply unit 51 . In addition, the substances smaller than the pores of the holding member 21 among the residues in which the modification reaction has not occurred in the char-filled layer 22 fall downward from the pores. At the bottom of the furnace body 11 , the residue is recovered by a dust recovery part 19 .

Here, an experimental example will be described. FIG. 4 is a diagram showing the configuration of the experimental device 9 . In the experimental device 9 , quartz beads 92 were filled in a cylindrical container 91 with a bottom, and a charred material filling layer 93 was formed by depositing simulated charred material on the quartz beads 92 . The simulated char is powdered charcoal. An electric heater 97 is provided around the cylindrical container 91, and the cylindrical container 91 is heated to 1100°C. A cover member 911 is attached to the upper portion of the cylindrical container 91 , and the cover member 911 is provided with an inflow port 912 . Through the inflow port 912 , simulated gas, simulated tar, water vapor, oxygen, and simulated burnt matter can be supplied into the cylindrical container 91 . The simulated gas includes components present in actual pyrolysis gas, and is a mixed gas of N ₂ , CO ₂ , H ₂ , CO, and CH ₄ . The simulated tar is toluene. Oxygen is used to simulate partial combustion of gases and the like.

Furthermore, the cover member 911 is provided with nozzles 94 (hereinafter referred to as "in-layer nozzles 94"). The ejection port at the tip of the in-layer nozzle 94 is arranged inside the charred material-filled layer 93 , specifically, at the center of the charred material-filled layer 93 in the vertical direction. Water vapor can be supplied to the in-layer nozzle 94 . The lower end of the cylindrical container 91 is provided with an outflow port 913 for simulated gas or the like. The gas discharged from the outflow port 913 is guided to the detector 95 (gas chromatograph) via the burnt matter collecting part 951, and the concentration of simulated tar contained in the gas is detected.

In the experiment, simulated gas, simulated tar, and simulated burnt matter were supplied from the inflow port 912 into the cylindrical container 91 under the conditions shown in Table 1. Then, the simulated tar concentration in the gas discharged from the cylindrical container 91 was measured by the detector 95 . At this time, in Case 1, oxygen and water vapor were supplied from the inflow port 912 into the cylindrical container 91 in a state in which the charred material filling layer 93 was omitted. In Case 2, oxygen and water vapor were supplied from the inflow port 912 into the cylindrical container 91 with the charred material filled layer 93 provided. In Case 3, oxygen and water vapor were supplied into the charred matter filled layer 93 from the discharge ports of the in-layer nozzles 94 in the state where the charred matter filled layer 93 was provided. In Case 4, oxygen was supplied from the inflow port 912 into the cylindrical container 91 in the state where the charred material filled layer 93 was provided, and water was supplied into the charred material filled layer 93 from the discharge port of the nozzle 94 in the layer. steam. The supply amounts of oxygen and water vapor are the same in either case.

(Table 1)

FIG. 5 is a graph showing experimental results. As shown in FIG. 5 , it can be seen that in Case 4, compared with any of Cases 1 to 3, the simulated tar concentration was significantly reduced, and the decomposition rate (modification rate) of simulated tar was higher. In Case 4, since oxygen is supplied from the inflow port 912 into the cylindrical container 91, similarly to the tar burner 3 of the gas reforming furnace 1 in FIG. Before filling the layer 93, simulate gas and simulate tar combustion. In addition, like the packed bed holding part 2 and the steam ejection part 4, the unburned simulated tar is collected by the charred matter filled layer 93, and is sprayed into the charred matter filled layer 93 from the ejection port of the nozzle 94 in the layer. The water vapor released can modify the simulated tar and simulated char.

As described above, the gas reforming furnace 1 includes the tar combustion unit 3 , the packed bed holding unit 2 , and the steam ejection unit 4 . In the tar combustion unit 3 , before the pyrolysis gas passes through the charred material filled layer 22 , the combustion of the tar contained in the pyrolysis gas proceeds. In addition, the tar remaining in the pyrolysis gas is collected in the charred matter-filled layer 22, and the water vapor is ejected from the ejection port 411 provided inside the charred matter-filled layer 22 in the steam ejection part 4, so that Steam modification of tar and char is carried out in the char-filled layer 22 . Thereby, reformation of the pyrolysis gas and gasification of recovered char can be performed appropriately, and the concentration of tar contained in the pyrolysis gas can be significantly reduced. As a result, the load of the gas refining process in the gas refining unit 83 is reduced, and the occurrence of troubles caused by residual tar in the gas engine 85 can also be suppressed.

It is also possible to modify the tar in the pyrolysis gas by using a general catalyst. However, at this time, in order to prevent catalyst clogging due to burnt matter and dust contained in the pyrolysis gas, it is necessary to install a dust collector between the gasification furnace and the gas reforming furnace. In addition, when the raw material is waste, acid gas components such as sulfur (S) and chlorine (Cl) in the waste contaminate the catalyst and deactivate the catalyst. Therefore, the catalyst cannot be used for a long period of time, the catalyst needs to be replaced, and the operating cost of the gas reforming furnace increases.

On the other hand, in the gas reforming furnace 1 , the recovered char produced in the gasification furnace 81 is used to form the char-filled layer 22 , and the tar is reformed using the char-filled layer 22 . In addition, modification (gasification) of recovered charred material in the charred material filled layer 22 is also carried out. As a result, the energy of the raw material can be utilized without waste. In addition, since the above-mentioned catalyst requiring replacement is not used, the running cost of the gas reforming furnace 1 can also be suppressed.

In the gas reforming furnace 1, the supply amount of recovered charred matter supplied from the charred matter supply unit 51 is controlled based on the layer thickness acquired by the layer thickness acquiring unit 52, so that the thickness of the charred matter filled layer 22 can be accurately adjusted. keep constant. As a result, the space (upstream side space 101 ) required for burning tar and the thickness of the char-filled layer 22 that traps tar can be appropriately maintained, and the concentration of tar contained in the pyrolysis gas can be stably reduced. In addition, the filled layer holding unit 2 has a holding member 21 formed with a plurality of holes so that the charred material filled layer 22 can be properly held.

FIG. 6 is a diagram showing another example of the steam ejection unit 4 . The steam ejection unit 4 of FIG. 6 is provided with a plurality of steam nozzles 41a. The plurality of steam nozzles 41a are arranged at equal angular intervals in the circumferential direction centering on the central axis J1 of the furnace main body 11 on a surface perpendicular to the gas flow direction. The tip of each steam nozzle 41a is provided with a discharge port 411, and the arrow marked with reference sign A2 in FIG. 6 indicates the direction in which steam is sprayed from each steam nozzle 41a. In the example of FIG. 6 , the ejection directions of the plurality of steam nozzles 41 a are set so that the trajectories of the water vapor ejected from the plurality of water vapor nozzles 41 a form a square shape. From the viewpoint of supplying water vapor (in other words, efficiently diffusing water vapor) to a wide range in the plane perpendicular to the gas flow direction inside the charred material filled layer 22 where water vapor is not easy to diffuse, it is preferable to As shown in FIG. 6 , three or more ejection ports 411 in the steam ejection unit 4 are arranged at the same position in the gas flow direction.

FIG. 7 is a diagram showing another example of the steam ejection unit 4 . In the water vapor ejection unit 4 of FIG. 7 , a plurality of (two in FIG. 7 ) water vapor tubes 41 are provided at intervals in the gas flow direction. Thereby, water vapor can be supplied to a wide range in the gas flow direction inside the charred material filled layer 22 . As a result, the concentration of tar contained in the pyrolysis gas can be further reduced. Of course, three or more steam pipes 4 may be arranged at intervals in the gas flow direction. In addition, a plurality of steam nozzles 41a may be arranged at intervals in the gas flow direction.

The discharge port 411 in the steam discharge part 4 may be provided outside the charred material filled bed 22 as long as it is provided in the vicinity of the charred material filled bed 22 . In the example of FIG. 8 , the water vapor pipe 41 is provided at a position slightly separated from the surface of the charred material filled layer 22 . The plurality of outlets 411 of the steam pipe 41 open downward in FIG. 8 , that is, open toward the charred material filled bed 22 side. The water vapor from the ejection port 411 is ejected toward the surface of the charred material filled layer 22 (see arrow A3 indicating the ejection direction of the water vapor). In this case, too, tar and char can be efficiently modified in the char-filled layer 22 . Here, the distance between the discharge port 411 disposed near the charred material-filled layer 22 and the surface of the charred material-filled layer 22 is preferably 1/3 or less of the distance between the discharge port 411 and the oxidizing gas nozzle 31 , more preferably below 1/5. At this time, it can be considered that the water vapor is directly ejected from the ejection port 411 to the charred material filled layer 22 .

The above-mentioned gasification system 8 and gas reforming furnace 1 can be modified in various ways.

In the upstream space 101 at a position away from the charred material filled layer 22 , water vapor may be introduced in addition to the oxidizing gas. However, in order to properly combust the tar contained in the pyrolysis gas in the upstream space 101, the flow rate of the oxidizing gas is preferably greater than the flow rate of the water vapor, and it is more preferable not to introduce the water vapor. In addition to spraying water vapor, an oxidizing gas may be sprayed inside or near the charred material filled layer 22 . At this time, in order to properly steam-modify the tar in the charred material-filled layer 22, it is preferable that the flow rate of the water vapor is larger than the flow rate of the oxidizing gas, and it is more preferable not to blow the oxidizing gas.

From the viewpoint of widening the range of the gas flow direction of the steam reforming reaction of tar and char in the charred material filled layer 22, it is preferable that at least one outlet 411 of the steam ejection part 4 is arranged on the side from the holding member. 21 is located upstream by 1/3 or more of the thickness of the charred material filled layer 22 , more preferably located upstream from the holding member 21 by 1/2 or more of the thickness.

Depending on the design of the gas reforming furnace 1 , the holding member 21 of the packed bed holding unit 2 may be provided near the outflow port 112 . In addition, the charred material filling layer 22 may be held at the bottom of the furnace main body 11 , and in this case, the bottom functions as the filling layer holding portion 2 . The pyrolysis gas passing through the charred material filled layer 22 is discharged from the furnace main body 11 through the outflow port 112 provided at the bottom.

The pyrolysis gas (ie, reformed gas) reformed by the gas reforming furnace 1 can be applied to gas turbines, fuel cells (solid oxide fuel cells (SOFC), etc.). In addition, the reformed gas can be used for various purposes as a fuel gas, and can also be converted into a liquid to be used as a liquid fuel.

The configurations in the above-described embodiments and modifications can be appropriately combined as long as they do not contradict each other.

As mentioned above, although this invention was concretely demonstrated, the said description is an illustration rather than a limitative description. Accordingly, various modifications and modes may be employed without departing from the scope of the present invention.

Claims (5)

1. A gas reforming furnace, which reforms the pyrolysis gas supplied from a gasifier, said gas reforming furnace is characterized in that it comprises: The main body of the furnace forms a flow channel for the flow of pyrolysis gas; a filled layer holding part provided in the flow channel, and holds the charred material filled layer filled with the charred material; The tar combustion unit supplies oxygen-containing gas to the pyrolysis gas in a space upstream of the charred material filled layer in the flow channel, so that the pyrolysis gas passes through the charred material. Combusting tars contained in said pyrolysis gases prior to filling the bed; and The steam jetting unit jets out steam from a jet port provided inside the charred material-filled bed or near the charred material-filled bed. 2 . The gas reforming furnace according to claim 1 , wherein the filled layer holding unit has a holding member formed with a plurality of holes and holds the charred material filled layer from below. 3 . 3. The gas reforming furnace according to claim 1 or 2, further comprising: a charred material supply unit that supplies the charred material to the filled layer holding unit; a layer thickness obtaining unit that obtains the thickness of the charred material filled layer; and The control unit controls the supply amount of the charred material supplied from the charred material supply unit based on the thickness. 4. The gas reforming furnace according to any one of claims 1 to 3, characterized in that, in the flow direction of the pyrolysis gas, from the supply position of the oxygen-containing gas to the charred object The length of the tar burning portion to the surface of the filled layer is greater than the thickness of the charred material filled layer. 5. The gas reforming furnace according to any one of claims 1 to 4, characterized in that the temperature of the space on the downstream side of the charred material filling layer in the flow channel is lower than that of the The temperature in the char-filled bed.