JP2018172481A - A gas reforming furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the gas reforming furnace capable of greatly reducing a concentration of tar contained in a pyrolysis gas.SOLUTION: The gas reforming furnace 1 has a furnace body 11 forming a flow channel 100 through which the pyrolysis gas supplied from a gasification furnace 81 flows. A packed bed holding part 2 holds a char packed layer 22 that is provided in the flow channel 100 and is filled with char. A tar burning part 3 burns tar contained in the pyrolysis gas in a space on the upstream side of the char packed bed 22 in the flow channel 100 by supplying a gas containing oxygen to the pyrolysis gas, before the pyrolysis gas passes through the char packed layer 22. A water vapor ejecting part 4 ejects water vapor from an ejection port provided inside the char packed layer 22. As a result, the concentration of the tar contained in the pyrolysis gas can be greatly reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas reforming furnace.

Conventionally, raw materials containing carbon such as biomass have been gasified. In the gasification of the raw material, a pyrolysis gas is generated by pyrolyzing the raw material at 500 to 800 ° C. in a gasification furnace. The pyrolysis gas includes not only gas but also tar vapor and powder char. The pyrolysis gas is sent to a subsequent gas reforming furnace. Inside the gas reforming furnace, a high temperature state of 1000 ° C. or higher is maintained by partial combustion by supplying oxygen, heating with a high temperature gas, or heating by a heater, and steam is blown in. Thereby, the tar and char in the pyrolysis gas are steam reformed and converted into a fuel gas such as hydrogen (H ₂ ) or 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 by a gas purification unit.

  In Patent Document 1, a biomass gasifier is disclosed. The gasification section of the apparatus includes a first retention section that guides the char flowing down from the thermal decomposition section while temporarily retaining the char, and an oxidizing gas such as air in a downstream passage that communicates with the first retention section. A first oxidant gas supply unit for introducing gas, a second stagnation part for temporarily retaining the char flowing down from the downflow passage, a gas extraction port formed at the upper end of the second stagnation part, and air in the second stagnation part And a second oxidizing gas supply unit for introducing the oxidizing gas. In the apparatus, the pyrolysis gas containing tar content passes through the flow-down passage and flows toward the gas extraction port. A combustion reaction occurs in the char and pyrolysis gas by the air supplied from the first oxidizing gas supply unit, and the temperature of the downstream passage is increased. Thereby, the tar content in the pyrolysis gas is pyrolyzed and gasified. On the other hand, in the char that has flowed down to the second stagnation part, a combustion reaction is generated 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 extraction port, it reacts with the char to produce carbon monoxide and hydrogen.

  Moreover, in patent document 2, in the fixed bed type gasification furnace which deposits a char filling layer in the bottom part, the gasification apparatus which performs the gasification of char and the decomposition | disassembly of tar by allowing pyrolysis gas to pass through the char filling layer is disclosed. It is disclosed. Further, by providing an air nozzle for ejecting compressed air in the char packed bed and controlling the air nozzle based on the temperature upstream and downstream of the char packed bed, blow-through may occur in the char packed bed. Is prevented.

JP 2007-177106 A JP 2007-231063 A

  By the way, there is a case where tar in the pyrolysis gas cannot be sufficiently decomposed by the above-described method of simply blowing oxygen and water vapor inside the gas reforming furnace. In this case, there is a concern that the processing in the gas purification unit and the power generation in the gas engine may be hindered due to the influence of the residual tar. Accordingly, there is a need for a technique that significantly reduces the concentration of tar contained in the pyrolysis gas.

  This invention is made | formed in view of the said subject, and aims at reducing the density | concentration of the tar contained in pyrolysis gas significantly.

  The invention described in claim 1 is a gas reforming furnace for reforming pyrolysis gas supplied from a gasification furnace, the furnace main body forming a flow path through which the pyrolysis gas flows, and provided in the flow path And supplying a gas containing oxygen to the pyrolysis gas in a packed bed holding portion that holds a char packed bed filled with char and a space upstream of the char packed bed in the flow path, Before the pyrolysis gas passes through the char packed bed, a tar combustion section for burning the tar contained in the pyrolysis gas, and provided in the interior of the char packed bed or in the vicinity of the char packed bed A water vapor ejecting portion for ejecting water vapor from the spout.

  Invention of Claim 2 is the gas reforming furnace of Claim 1, Comprising: The said packed bed holding | maintenance part is a holding member which hold | maintains the said char packed bed from the bottom while a some hole is formed Have

  Invention of Claim 3 is a gas reforming furnace of Claim 1 or 2, Comprising: The char supply part which supplies char to the said packed bed holding | maintenance part, and acquires the thickness of the said char packed bed The apparatus further includes a layer thickness acquisition unit and a control unit that controls the amount of char supplied by the char supply unit based on the thickness.

  According to a fourth aspect of the present invention, there is provided the gas reforming furnace according to any one of the first to third aspects, wherein the char is introduced from a supply position of the gas containing oxygen with respect to a direction in which the pyrolysis gas flows. The length of the tar combustion part reaching the surface of the packed bed is larger than the thickness of the char packed bed.

  A fifth aspect of the present invention is the gas reforming furnace according to any one of the first to fourth aspects, wherein the temperature of the space downstream of the char packed bed in the flow path is the char. Lower than the temperature in the packed bed.

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

It is a figure which shows the structure of a gasification system. It is a figure which shows the structure of a water vapor | steam ejection part. It is a figure which shows the structure of a water vapor | steam ejection part. It is a figure which shows the structure of an experimental apparatus. It is a figure which shows an experimental result. It is a figure which shows the other example of a water vapor | steam ejection part. It is a figure which shows the other example of a water vapor | steam ejection part. It is a figure which shows the other example of a water vapor | steam ejection part.

  FIG. 1 is a diagram showing a configuration of a gasification system 8 according to an embodiment of the present invention. The gasification system 8 includes a gasification furnace 81, a gas reforming furnace 1, a boiler 82, a gas purification unit 83, an induction fan 84, a gas engine 85, and a chimney 86. In the gasification system 8, an entire flow path is formed through the gasification furnace 81, the gas reforming furnace 1, the boiler 82, the gas purification unit 83, the induction fan 84, the gas engine 85, and the chimney 86 in this order. When the induction fan 84 is driven, a pyrolysis gas, which will be described later, generated in the gasification furnace 81 flows toward the chimney 86 through the entire flow path.

  The gasification furnace 81 is, for example, a kiln gasification furnace, a fixed bed gasification furnace, a fluidized bed gasification furnace, or the like. The gasification furnace 81 is charged with waste or biomass (hereinafter simply referred to as “raw material”). Examples of the raw material include general waste, industrial waste, sludge, and woody biomass. The raw material is pyrolyzed and gasified by being heated at 400 to 800 ° C., for example. Thereby, pyrolysis gas is produced | generated. The pyrolysis gas includes not only gas but also tar vapor and powder char. The pyrolysis gas is supplied to the gas reforming furnace 1. A char recovery unit (not shown) for recovering char not included in the pyrolysis gas is provided at the bottom of the gasification furnace 81. The recovered char (hereinafter referred to as “recovered char”) is supplied into the furnace body 11 of the gas reforming furnace 1 by a screw feeder 511 described later.

  In the gas reforming furnace 1, reforming of carbon-containing non-gas components such as tar and char contained in the pyrolysis gas is performed. The configuration 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 temperature of the reformed gas decreases due to heat exchange with the circulating water that circulates inside. The reformed gas flows from the boiler 82 into the gas purification unit 83. In the gas purification unit 83, purification processing such as dust and mist removal, demineralization, and desulfurization is performed on the reformed gas. The reformed gas after the purification process is, for example, about 50 ° C., and is supplied to the gas engine 85 via the induction fan 84. The gas engine 85 generates power using the reformed gas as fuel. The exhaust gas obtained by burning the reformed gas in the gas engine 85 is discharged to the atmosphere via the chimney 86.

  The circulating water in the boiler 82 becomes steam by heat exchange with the reformed gas. A part of the water vapor is supplied to a water vapor ejection section 4 described later in the gas reforming furnace 1. The remainder of the steam is used to drive the steam turbine 821 and then returned to the inside of the boiler 82 as circulating water. The steam may be supplied to the gasification furnace 81 and used for heating the raw material.

  The gas reforming furnace 1 includes a furnace 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 water vapor ejection unit 4, and a control unit 10. . The control unit 10 is responsible for overall control of the gas reforming furnace 1. The control unit 10 may take overall control of the gasification system 8.

  The furnace body 11 has, for example, a substantially cylindrical shape. An inlet 111 connected to the gasification furnace 81 is provided at one end of the furnace body 11. At the other end, an outlet 112 connected to the boiler 82 is provided. Pyrolysis gas from the gasification furnace 81 flows into the furnace body 11 through the inlet 111. The pyrolysis gas flows inside the furnace body 11 toward the outlet 112 and flows out to the boiler 82 through the outlet 112. Thus, in the furnace main body 11, the flow path 100 through which the pyrolysis gas flows is formed. The shape of the furnace body 11 may be changed as appropriate, and may be, for example, a U-shape.

  The packed bed holding unit 2 includes a plate-like holding member 21 provided in the flow path 100. The holding member 21 extends approximately perpendicular to the flow direction of pyrolysis gas from the inlet 111 toward 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 the present embodiment, the gas flow direction is parallel to the vertical direction. The holding member 21 is formed with a plurality of (multiple) holes uniformly dispersed, and the pyrolysis gas passes through the plurality of holes. The holding member 21 is formed of, for example, ceramics, porcelain, refractory material, concrete, metal or the like. Char is deposited on the holding member 21. In other words, the char filling layer 22 filled with char is provided on the holding member 21. The char filling layer 22 extends over the entire upper surface of the holding member 21. The char filling layer 22 is held by the holding member 21 from below.

  The char supply unit 51 includes a screw feeder 511. One end of the screw feeder 511 is connected to the char recovery unit of the gasification furnace 81. The other end of the screw feeder 511 is connected to the furnace body 11 of the gas reforming furnace 1. In the furnace body 11, a char supply port 113 is provided between the packed bed holding unit 2 and the inflow port 111. By driving the screw feeder 511, the recovered char is conveyed from the char recovery unit to the char supply port 113 and is supplied to the packed bed holding unit 2. In the gas reforming furnace 1, the control unit 10 controls the screw feeder 511 to adjust the supply amount of the recovered char (recovery char feed rate). In the char supply unit 51, a powder feeder such as a table feeder may be provided in addition to the screw feeder 511, and the recovered char may be supplied to the packed bed holding unit 2 through a chute. Further, depending on the structure of the gasification furnace 81 and the gas reforming furnace 1, the bottom of the gasification furnace 81 is connected to the top of the furnace body 11, and the recovered char is simply dropped from the bottom so that the recovered char becomes a packed bed. It may be supplied to the holding unit 2. In this case, for example, a mechanism (for example, a gate) for adjusting the fall amount of the recovered char from the bottom of the gasification furnace 81 may be provided.

  The layer thickness acquisition unit 52 includes a level sensor 521. The level sensor 521 is of a laser type and detects the height of the surface of the char filling layer 22 (the upper surface in FIG. 1). The value detected by the level sensor 521 is output to the control unit 10. Actually, by detecting the height of the surface of the char filling layer 22, the distance between the holding member 21 of the filling layer holding unit 2 and the surface of the char filling layer 22, that is, the thickness of the char filling layer 22 (hereinafter referred to as the thickness of the char filling layer 22). , Referred to as “layer thickness”). In the control unit 10, the supply amount of the recovered char to the packed bed holding unit 2 by the char supply unit 51 is controlled based on the acquired layer thickness. Actually, the supply amount of the recovered char is controlled so that the layer thickness maintains a constant value.

  As described above, since the char supply unit 51 replenishes the char filling layer 22 with the recovered char by extrusion from the char supply port 113, the surface of the char filling layer 22 is undulated. Then, since the exact layer thickness is not necessarily required, it is not a problem. Of course, the layer thickness may be obtained with high accuracy by providing a plurality of level sensors 521 and obtaining the average value of the detection values by these. In the layer thickness acquisition unit 52, the layer thickness may be acquired by obtaining a difference between a pressure at a position upstream of the char filling layer 22 and a pressure at a downstream position.

  When the amount of char generated in the gasification furnace 81 is excessively larger than the amount of recovered char supplied to the packed bed holding unit 2 by the char supply unit 51, the recovered char is passed through a gate (not shown). It may be discharged outside. In this case, the gasification efficiency of the raw material may be improved by re-introducing the recovered char discharged to the outside into the gasification furnace 81. On the other hand, when the amount of char generated in the gasification furnace 81 is insufficient with respect to the supply amount to be supplied to the packed bed holding unit 2, charcoal, coal, activated carbon, or the like is supplementary to the packed bed holding unit 2. May be supplied. The ratio of char generated from the raw material depends on the heating temperature in the gasification furnace 81. For example, in an example of the kiln type gasification furnace 81, when the heating temperature is 400 ° C., the ratio of char generated from the raw material is about 50%, and when the heating temperature is 600 ° C., the ratio of char is 30%. %. Thus, when the heating temperature in the gasification furnace 81 is increased, the ratio of char generated from the raw material is decreased.

  The tar combustion unit 3 includes a plurality of oxidizing gas nozzles 31 and an oxidizing gas supply unit 32. The plurality of oxidizing gas nozzles 31 is a space 101 on the upstream side of the char filling layer 22 in the flow channel 100 (a space on the inlet 111 side of the char filling layer 22, hereinafter simply referred to as “upstream space 101”). Placed in. The oxidizing gas supply unit 32 supplies a gas containing oxygen (hereinafter referred to as “oxidizing gas”) to the oxidizing gas nozzle 31. The oxidizing gas is, for example, air. The oxidizing gas may be oxygen itself. The oxidizing gas from the oxidizing gas supply unit 32 is ejected into the upstream space 101 by the plurality of oxidizing gas nozzles 31. In the tar combustion unit 3, the oxidizing gas nozzles 31 may be provided in multiple stages in the gas flow direction on the side wall of the furnace body 11. Further, the oxidizing gas nozzle 31 may be provided on the upper surface portion of the furnace body 11.

  2 and 3 are diagrams showing the configuration of the water vapor ejection portion 4. FIG. 2 shows a cross section (a cross section seen from the inlet 111) of the furnace main body 11 perpendicular to the gas flow direction at the position of a steam pipe 41 described later, and FIG. 3 shows the furnace main body 11 parallel to the gas flow direction. The cross section of is shown. The water vapor ejection part 4 has a water vapor pipe 41, and the water vapor supplied from the boiler 82 flows through the water vapor pipe 41. The steam pipe 41 has a plurality of folded portions folded in a U shape on a surface perpendicular to the gas flow direction. The plurality of folded portions are arranged inside the furnace body 11, specifically, inside the char filling layer 22. A plurality of jet nozzles 411 are provided in a portion of the steam pipe 41 disposed inside the furnace body 11. In the example of FIG. 3, the plurality of jet nozzles 411 open toward the side opposite to the holding member 21, that is, toward the upstream space 101 side. In the water vapor ejection portion 4, water vapor is ejected from the plurality of ejection ports 411. The temperature of the water vapor is about 300 ° C., for example. In FIG. 3, the direction of water vapor ejection at each ejection port 411 is indicated by an arrow labeled A <b> 1.

  The length of the portion disposed inside the furnace body 11 in the steam pipe 41 is preferably equal to or greater than the diameter of the furnace body 11, and more preferably twice or more the diameter of the furnace body 11. This makes it possible to easily disperse and eject water vapor in a wide range on a plane perpendicular to the gas flow direction. The length of the said part is 10 times or less of the diameter of the furnace main body 11, for example. The plurality of jet nozzles 411 may open toward the holding member 21 side. The steam supplied to the steam pipe 41 may be generated using heat of exhaust gas from the gas engine 85 or an external heat source.

  In the gas reforming furnace 1 of FIG. 1, the pyrolysis gas supplied from the inlet 111 to the inside of the furnace body 11 (flow path 100) flows toward the char packed bed 22 in the upstream space 101. In the upstream space 101, the oxidizing gas is supplied to the pyrolysis gas by the plurality of oxidizing gas nozzles 31, and not only the gas contained in the pyrolysis gas but also the tar vapor is partially combusted. Due to the continuous partial combustion of the pyrolysis gas, a high temperature state is maintained in the upstream space 101, and for example, the temperature of the upstream space 101 is 800 to 1200 ° C. Thus, in the tar combustion part 3, before the pyrolysis gas reaches the char packed bed 22, the tar contained in the pyrolysis gas burns, and the concentration of tar is reduced. In the tar combustion section 3, other reactions may occur in addition to the combustion reaction.

  From the viewpoint of ensuring a sufficient space for the combustion of tar, the tar from the supply position of the oxidizing gas (here, the oxidizing gas nozzle 31 farthest from the char filling layer 22) to the surface of the char filling layer 22 in the gas flow direction. It is preferable that the length of the combustion part 3 is larger than the thickness of the char filling layer 22. Here, the position of the surface of the char filling layer 22 is, for example, an averaged position of the surface. More preferably, the length of the tar combustion part 3 is 1.5 times or more the thickness of the char filling layer 22. The length of the tar combustion part 3 is, for example, 10 times or less the thickness of the char filling layer 22. Depending on the design of the gas reforming furnace 1, the length of the tar combustion unit 3 may be equal to or less than the thickness of the char filling layer 22.

  The pyrolysis gas that has reached the char packed bed 22 passes through the gaps between the recovered chars in the char packed bed 22 and the holes of the holding member 21, and the space 102 on the downstream side of the char packed bed 22 in the flow path 100. (It is a space on the outflow port 112 side of the char packed bed 22, and hereinafter simply referred to as “downstream space 102”). When the pyrolysis gas passes through the char packed bed 22, tar remaining in the pyrolysis gas and powder char are collected (trapped) in the pores of the recovered char of the char packed bed 22. Further, due to the combustion of the pyrolysis gas in the upstream space 101, the char packed bed 22 and the pyrolyzed gas flowing through the char packed bed 22 are at a high temperature. Furthermore, water vapor is ejected vigorously (for example, at a flow rate higher than the flow rate of the pyrolysis gas) from the plurality of ejection ports 411 (see FIG. 2) of the water vapor ejection portion 4 toward the recovered char of the char packed bed 22. . As a result, the tar and powder char collected in the recovered char and the recovered char itself are converted (reformed) into a fuel gas such as hydrogen or carbon monoxide by the steam reforming reaction. In the char packed bed 22, it can be understood that the reforming reaction of tar is promoted by the recovered char, that is, the recovered char plays a role as a catalyst.

  The reformed pyrolysis gas, that is, the reformed gas, passes through the downstream space 102, reaches the outlet 112, and is discharged to the boiler 82. Typically, in the char packed bed 22 and the downstream space 102, no oxidizing gas is supplied and no combustion reaction occurs. Further, the steam reforming reaction such as tar is an endothermic reaction. Accordingly, the temperature of the downstream space 102 is, for example, less than 1200 ° C., and is lower than the temperatures in the upstream space 101 and the char packed layer 22.

  In the char packed bed 22, when the recovered char is reduced due to the reforming, a new recovered char is replenished by the char supply unit 51. In addition, among the residues that do not undergo the reforming reaction in the char-filled layer 22, those that are smaller than the hole of the holding member 21 fall downward from the hole. The residue is recovered by the ash recovery unit 19 at the bottom of the furnace body 11.

Here, an experimental example will be described. FIG. 4 is a diagram showing a configuration of the experimental apparatus 9. In the experimental apparatus 9, quartz beads 92 are packed in a bottomed cylindrical container 91, and a char-filled layer 93 is formed by depositing simulated char on the quartz beads 92. The simulated char is charcoal powder. An electric heater 97 is provided around the cylindrical container 91, and the cylindrical container 91 is heated to 1100 ° C. A lid member 911 is attached to the upper part of the cylindrical container 91, and an inflow port 912 is provided in the lid member 911. Simulated gas, simulated tar, water vapor, oxygen gas, and simulated char can be supplied into the cylindrical container 91 through the inflow port 912. The simulated gas contains components present in the actual pyrolysis gas and is a mixed gas of N ₂ , CO ₂ , H ₂ , CO, and CH ₄ . The simulated tar is toluene. The oxygen gas is for partial combustion such as simulated gas.

  The lid member 911 is provided with a nozzle 94 (hereinafter referred to as “in-layer nozzle 94”). The jet outlet at the tip of the in-layer nozzle 94 is disposed inside the char filling layer 93, specifically, at the center of the char filling layer 93 in the vertical direction. Water vapor can be supplied to the in-layer nozzle 94. An outlet 913 for simulated gas or the like is provided at the lower end of the cylindrical container 91. The gas discharged from the outlet 913 is introduced into the detector 95 (gas chromatograph) via the char collection unit 951, and the concentration of the simulated tar contained in the gas is detected.

  In the experiment, simulated gas, simulated tar, and simulated char were supplied into the cylindrical container 91 from the inlet 912 under the conditions shown in Table 1. 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 gas and water vapor were supplied into the cylindrical container 91 from the inlet 912 in a state where the char filling layer 93 was omitted. In Case 2, oxygen gas and water vapor were supplied from the inflow port 912 into the cylindrical container 91 with the char packed layer 93 provided. In Case 3, with the char filling layer 93 provided, oxygen gas and water vapor were supplied into the char filling layer 93 from the jet nozzle of the in-layer nozzle 94. In Case 4, oxygen gas was supplied into the cylindrical container 91 from the inlet 912 and water vapor was supplied into the char packed layer 93 from the outlet of the in-layer nozzle 94 with the char packed layer 93 provided. The supply amounts of oxygen gas and water vapor are the same in both cases.

  FIG. 5 is a diagram showing experimental results. As shown in FIG. 5, in Case 4, the simulated tar concentration is significantly reduced as compared with any of Cases 1 to 3, and it can be seen that the decomposition rate (reforming rate) of the simulated tar is high. In Case 4, oxygen gas is supplied into the cylindrical vessel 91 from the inlet 912, so that the simulated gas and simulated tar (pyrolysis gas) are char-filled in the same manner as the tar combustion section 3 of the gas reforming furnace 1 in FIG. Prior to passing through the layer 93, the simulated gas and simulated tar burn. Similarly to the packed bed holding unit 2 and the steam jetting unit 4, unburned simulated tar is collected in the char packed bed 93 and is jetted into the char packed bed 93 from the jet nozzle of the in-layer nozzle 94. This modifies the simulated tar and the simulated char.

  As described above, the gas reforming furnace 1 includes the tar combustion unit 3, the packed bed holding unit 2, and the water vapor ejection unit 4. In the tar combustion section 3, the tar contained in the pyrolysis gas is burned before the pyrolysis gas passes through the char packed bed 22. In the char filling layer 22, tar remaining in the pyrolysis gas is collected, and in the water vapor ejection portion 4, water vapor is ejected from an ejection port 411 provided inside the char filling layer 22, thereby the char filling layer 22. At 22, steam reforming of tar and char is performed. Thereby, reforming of the pyrolysis gas and gasification of the 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 purification process in the gas purification unit 83 can be reduced, and the occurrence of troubles due to the residual tar in the gas engine 85 can be suppressed.

  By the way, it is possible to reform the tar in the pyrolysis gas by using a general catalyst. However, in this case, in order to prevent clogging of the catalyst due to char and dust contained in the pyrolysis gas, it is necessary to install a dust collector between the gasification furnace and the gas reforming furnace. When the raw material is waste, acidic gas components such as sulfur (S) and chlorine (Cl) in the waste poison the catalyst and deactivate it. Therefore, the catalyst cannot be used for a long period of time, the catalyst needs to be replaced, and the running cost of the gas reforming furnace increases.

  On the other hand, in the gas reforming furnace 1, the char packed bed 22 is formed using the recovered char generated in the gasification furnace 81, and tar reforming is performed using the char packed bed 22. Further, reforming (gasification) of the recovered char of the char packed bed 22 is also performed. As a result, the energy of the raw material can be used without waste. In addition, since the catalyst that needs to be replaced is not used, the running cost of the gas reforming furnace 1 can be suppressed.

  In the gas reforming furnace 1, the thickness of the char-filled layer 22 is accurately maintained constant by controlling the supply amount of the collected char by the char supply unit 51 based on the layer thickness acquired by the layer thickness acquisition unit 52. be able to. As a result, the space necessary for the combustion of tar (upstream space 101) and the thickness of the char packed bed 22 that collects tar can be appropriately maintained, and the concentration of tar contained in the pyrolysis gas can be reduced. It can be stably reduced. Moreover, the filling layer holding part 2 has the holding member 21 in which a plurality of holes are formed, whereby the char filling layer 22 can be appropriately held.

  FIG. 6 is a diagram illustrating another example of the water vapor ejection portion 4. In the water vapor ejection part 4 of FIG. 6, a plurality of water vapor nozzles 41a are provided. The plurality of water vapor nozzles 41a are arranged at equiangular intervals in the circumferential direction around the central axis J1 of the furnace body 11 on a plane perpendicular to the gas flow direction. Each water vapor nozzle 41a is provided with a spout 411 at the tip, and in FIG. 6, the direction of water vapor ejection from each water vapor nozzle 41a is indicated by an arrow labeled A2. In the example of FIG. 6, the ejection directions in the plurality of water vapor nozzles 41 a are set so that the trajectories of the water vapor ejected from the plurality of water vapor nozzles 41 a have a cross beam shape. From the viewpoint of supplying water vapor in a wide range in a plane perpendicular to the gas flow direction inside the char-packed layer 22 where water vapor is difficult to diffuse (in other words, efficiently diffusing water vapor), as shown in FIGS. Moreover, it is preferable that the 3 or more jet nozzles 411 in the water vapor jet part 4 are arrange | positioned in the same position regarding a gas flow direction.

  FIG. 7 is a view showing another example of the water vapor ejection part 4. 7, a plurality (two in FIG. 7) of steam pipes 41 are provided at intervals in the gas flow direction. This makes it possible to supply water vapor in a wide range in the gas flow direction inside the char packed bed 22. As a result, the concentration of tar contained in the pyrolysis gas can be further reduced. Of course, three or more steam pipes 41 may be provided at intervals in the gas flow direction. A plurality of water vapor nozzles 41a may be arranged at intervals in the gas flow direction.

  The ejection port 411 in the water vapor ejection part 4 may be provided outside the char filling layer 22 as long as it is provided in the vicinity of the char filling layer 22. In the example of FIG. 8, the water vapor pipe 41 is provided at a position slightly away from the surface of the char filling layer 22. In the water vapor pipe 41, a plurality of jet outlets 411 open downward in FIG. 8, that is, toward the char packed bed 22 side. The water vapor from the ejection port 411 is ejected to the surface of the char filling layer 22 (see arrow A3 indicating the direction of water vapor ejection). Also in this case, tar and char can be efficiently modified in the char packed layer 22. Here, the distance between the ejection port 411 disposed in the vicinity of the char filling layer 22 and the surface of the char filling layer 22 is 1/3 or less of the distance between the ejection port 411 and the oxidizing gas nozzle 31. It is preferable that it is 1/5 or less. In this case, it can be understood that water vapor is directly ejected from the ejection port 411 to the char packed bed 22.

  Various modifications are possible in the gasification system 8 and the gas reforming furnace 1.

  In a position away from the char filling layer 22 in the upstream space 101, water vapor may be introduced in addition to the oxidizing gas. However, in order to appropriately burn the tar contained in the pyrolysis gas in the upstream space 101, the flow rate of the oxidizing gas is preferably larger than the flow rate of the water vapor, and more preferably, the water vapor is not introduced. Further, an oxidizing gas may be ejected in addition to the water vapor in or near the char filling layer 22. Also in this case, in order to appropriately perform the steam reforming of tar in the char packed bed 22, the flow rate of the steam is preferably larger than the flow rate of the oxidizing gas, and more preferably, the oxidizing gas is not ejected.

  From the viewpoint of widening the range of the gas flow direction in which the steam reforming reaction of tar and char occurs in the char packed bed 22, at least one jet outlet 411 of the steam jet section 4 is char from the holding member 21 to the upstream side. It is preferable that the filler layer 22 is disposed at a position separated by 1/3 or more of the thickness, and more preferably disposed at a position separated 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 in the vicinity of the outlet 112. In addition, the char packed layer 22 may be held at the bottom of the furnace body 11, and in this case, the bottom serves as the packed bed holding unit 2. The pyrolysis gas that has passed through the char packed bed 22 is discharged from the furnace body 11 through the outlet 112 provided at the bottom.

  The pyrolysis gas (that is, the reformed gas) reformed by the gas reforming furnace 1 may be used in a gas turbine or a fuel cell (such as a solid oxide fuel cell (SOFC)). In addition, the reformed gas may be used as a fuel gas for various purposes, and may further be used as a liquid fuel by converting it into a liquid.

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

DESCRIPTION OF SYMBOLS 1 Gas reforming furnace 2 Packing bed holding | maintenance part 3 Tar combustion part 4 Water vapor | steam ejection part 10 Control part 11 Furnace main body 21 Holding member 22 Char filling layer 51 Char supply part 52 Layer thickness acquisition part 81 Gasification furnace 100 Flow path 101 Upstream side Space 102 Downstream space 411 Spout

Claims (5)

A gas reforming furnace for reforming pyrolysis gas supplied from a gasification furnace,
A furnace body forming a flow path through which pyrolysis gas flows;
A packed bed holding section that is provided in the flow path and holds a char packed bed filled with char;
By supplying a gas containing oxygen to the pyrolysis gas in a space upstream of the char filling layer in the flow path, the thermal decomposition gas passes through the char filling layer before the heat decomposition gas. A tar combustion section for burning the tar contained in the cracked gas;
A water vapor ejection part for ejecting water vapor from the inside of the char packed bed or a jet port provided in the vicinity of the char packed bed;
A gas reforming furnace comprising: The gas reforming furnace according to claim 1,
The gas reforming furnace, wherein the packed bed holding portion includes a plurality of holes and a holding member that holds the char packed bed from below. A gas reforming furnace according to claim 1 or 2, wherein
A char supply unit for supplying char to the packed bed holding unit;
A layer thickness acquisition unit for acquiring the thickness of the char filling layer;
A control unit for controlling the amount of char supplied by the char supply unit based on the thickness;
A gas reforming furnace further comprising: A gas reforming furnace according to any one of claims 1 to 3,
A gas characterized in that, with respect to a direction in which the pyrolysis gas flows, a length of the tar combustion part from a supply position of the gas containing oxygen to a surface of the char packed bed is larger than a thickness of the char packed bed Reforming furnace. A gas reforming furnace according to any one of claims 1 to 4,
A gas reforming furnace, wherein a temperature of a space downstream of the char packed bed in the flow path is lower than a temperature of the char packed bed.

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