JP6596888B2 - Tar reformer - Google Patents

Description

  The present invention relates to a tar reforming apparatus for reforming tar in a gasification gas generated by gasifying a gasification raw material.

  In recent years, a technology has been developed in which gasified raw materials such as unused fuel such as coal, biomass, and tire chips are gasified to generate gasified gas instead of oil. The gasified gas thus generated is used for power generation systems, hydrogen production, synthetic fuel (synthetic petroleum) production, chemical fertilizer (urea) and other chemical products. Among gasification raw materials used as raw materials for gasification gas, coal, in particular, has a recoverable period of about 150 years, which is more than three times the extractable period of oil, and reserves are unevenly distributed compared to oil. Therefore, it is expected as a natural resource that can be supplied stably over a long period of time.

  Conventionally, the gasification process of coal has been performed by partial oxidation using oxygen or air. However, since it is necessary to perform partial oxidation at a high temperature of 2000 ° C., there is a disadvantage that the cost of the gasification furnace increases. Had.

  In order to solve this problem, a technique (steam gasification) that uses steam to gasify coal at about 700 ° C. to 900 ° C. has been developed. In this technique, it is possible to reduce the cost by setting the temperature low, but the generated gasification gas is compared with a gasification gas generated by partial oxidation at a high temperature of 2000 ° C. Often contains a lot of tar. When the temperature of the gasification gas decreases in the process using the gasification gas generated by steam gasification, the tar contained in the gasification gas condenses, clogging the piping, failure of equipment used in the process, catalyst coverage. Problems such as poisoning will occur.

  As a technique for removing tar, a technique is disclosed in which the generated gasified gas is burned with oxygen or air to 1100 ° C. or higher and is oxidized and reformed (for example, Patent Document 1). However, in order to oxidize and reform tar, it is necessary to raise the temperature of the oxidation reforming furnace for the oxidation reforming reaction to 1100 ° C. or higher. The combustible gas (hydrogen and methane) in the gas had to be burned with oxygen and air. Therefore, since the combustible gas in the gasification gas is consumed, the ratio of the combustible gas per unit volume of the gasification gas treated in the oxidation reforming furnace may be reduced by about 10%, for example. .

  In view of this, a technique for reforming tar in gasification gas using a tar reforming catalyst and removing tar from the gasification gas has been developed (for example, Patent Document 2).

JP 2009-40862 A JP 2014-1256 A

  In the technique of Patent Document 2, the gasification gas is raised to a temperature suitable for the tar reforming catalyst by adding oxygen to the gasification gas and oxidizing it. However, when oxygen is added to the gasification gas, a flame may be generated. In this case, hydrocarbons and tar in the gasification gas become soot by the flame. If it does so, there exists a possibility that problems may arise, such as pipe | tube obstruct | occluded by a flaw or the apparatus used in a process failure. Accordingly, there is a demand for the development of a technique for raising the temperature of the gasification gas without generating a flame in a configuration in which tar is removed using a tar reforming catalyst.

  In view of such a problem, an object of the present invention is to provide a tar reformer capable of increasing the temperature of gasification gas without generating a flame.

In order to solve the above problem, the tar reforming apparatus of the present invention, the oxidation unit that holds the oxidation catalyst containing Pt, Ni, Ca, Mg, Fe, and one or more selected from the group of Si A reforming unit provided on the downstream side of the oxidation unit and an oxidizing agent containing at least oxygen is supplied only to the upstream side of the oxidation unit, and the oxidizing agent and the gasification gas are mixed. And a gas mixing section that generates a mixed gas without generating a portion that is not less than the lower limit value of the oxygen concentration at which a flame is generated, and sends out the mixed gas.

  Further, the gas mixing unit may be an ejector.

  According to the present invention, it becomes possible to raise the temperature of gasification gas, without producing a flame.

It is a figure for demonstrating a gasification gas production | generation apparatus. It is a figure for demonstrating a tar reforming apparatus. It is a figure for demonstrating the specific example of an oxidation unit.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Gasified gas generator 100)
FIG. 1 is a diagram for explaining a gasified gas generation apparatus 100. As shown in FIG. 1, the gasified gas generator 100 includes a combustion furnace 112, a medium separator (cyclone) 114, a gasifier 116, a tar reformer 200, and a purifier 300. Is done. In FIG. 1, the gasification raw material is indicated by a broken line arrow, the gas flow is indicated by a solid line arrow, and the flow of the fluid medium (sand) is indicated by a one-dot chain line arrow.

In the gasification gas generator 100, as a whole, a fluid medium composed of sand such as silica sand (silica sand) having a particle size of about 300 μm is circulated as a heat medium. Specifically, the fluid medium is first heated to about 1000 ° C. in the combustion furnace 112 and introduced into the medium separator 114 together with the combustion exhaust gas containing carbon dioxide (CO ₂ ). In the medium separation device 114, the high-temperature fluid medium and the combustion exhaust gas are separated, and the separated high-temperature fluid medium is introduced into the gasification furnace 116. Then, the fluidized medium introduced into the gasification furnace 116 is fluidized by a gasifying agent (water vapor) introduced from the bottom surface of the gasification furnace 116, and finally returned to the combustion furnace 112. Further, the combustion exhaust gas separated by the medium separator 114 is heat recovered by a boiler or the like.

  The gasification furnace 116 is, for example, a bubbling fluidized bed gasification furnace, which uses gasification raw materials such as coal such as lignite, solid raw materials such as petroleum coke, biomass and tire chips, and liquid raw materials such as black liquor. Gasification is generated by gasification at 700 ° C to 900 ° C. In the present embodiment, by supplying water vapor to the gasification furnace 116, the gasification raw material is gasified to generate gasified gas (water vapor gasification).

  Here, the gasification furnace 116 has been described by taking a circulating fluidized bed system as an example. However, if the gasification raw material can be gasified, the gasification furnace 116 may be a simple fluidized bed system or a sand having its own weight. The moving bed method may be used in which the moving bed is formed by flowing downward in the vertical direction.

  Since the gasification gas X1 generated in the gasification furnace 116 contains tar, water vapor, and the like, the tar is reformed by the tar reforming device 200 described later, and the gasification gas X2 in which the tar is reformed. Is further purified by the purification apparatus 300.

  The refining device 300 includes a heat exchanger that cools the gasification gas X2 sent from the tar reforming device 200, a spray tower that removes tar and sludge by spraying water on the gasification gas cooled by the heat exchanger, A mist separator that further removes tar and sludge by spraying atomized water onto the gasification gas, a booster that pressurizes the gasification gas from which tar and sludge have been removed, a desulfurization device that removes sulfides from the gasification gas, A denitration device that removes nitrides from the gasification gas, a demineralization device that removes chlorides from the gasification gas, and the like are configured, and the gasification gas X2 whose tar is reformed by the tar reforming device 200 is purified. .

(Tar reformer 200)
Subsequently, a specific configuration of the tar reforming apparatus 200 will be described. FIG. 2 is a diagram for explaining the tar reforming apparatus 200. As shown in FIG. 2, the tar reforming apparatus 200 includes a gas mixing unit 210, an oxidation unit 220, and a reforming unit 230.

  The gas mixing unit 210 is constituted by, for example, an ejector, receives the gasified gas X1 generated in the gasification furnace 116, mixes the gasified gas X1 and the oxidant, generates a mixed gas, and sends the mixed gas To do. Here, the oxidizing agent is a gas containing at least oxygen.

  When the gas mixing unit 210 is configured with an ejector, the linear velocity of the gasification gas X1 can be improved to produce a swirling flow. By introducing the oxidant into the swirling flow of the gasified gas X1, the gasified gas X1 and the oxidant can be mixed substantially uniformly. Thereby, a mixed gas can be produced | generated, without producing the part from which oxygen concentration becomes more than a predetermined density | concentration in mixed gas. Here, the predetermined concentration is a lower limit value of the oxygen concentration at which a flame is generated. Therefore, it is possible to avoid a situation where a flame is generated in the process of generating the mixed gas.

  The oxidation unit 220 includes an oxidation catalyst that promotes an oxidation reaction of the mixed gas and a carrier that holds the oxidation catalyst, and is provided on a flow path through which the mixed gas mixed in the gas mixing unit 210 flows. The catalyst is brought into contact with the mixed gas. Here, the oxidation catalyst includes, for example, platinum (Pt), and the support may be formed of a metal, or may be formed of a ceramic such as cordierite, mullite, or alumina.

  FIG. 3 is a diagram for explaining a specific example of the oxidation unit 220. In FIG. 3, the flow of the mixed gas is indicated by a white arrow, and the oxidation catalysts 224 and 228 are indicated by black filling.

  For example, as illustrated in FIG. 3A, the oxidation unit 220 is configured by a flat plate that divides the mixed gas flow path 202 into a plurality (for example, eight) in a direction orthogonal to the flow direction of the mixed gas. The carrier 222 and the oxidation catalyst 224 supported on the surface of the carrier 222 are configured.

  Since the oxidation unit 220 holds the oxidation catalyst 224 in a plane parallel to the flow direction of the mixed gas, at least a part of the mixed gas can be reliably brought into contact with the oxidation catalyst 224. When the mixed gas comes into contact with the oxidation catalyst 224, the oxidation reaction is started. Therefore, the oxidation reaction can be advanced in the entire mixed gas starting from the position where the oxidation reaction is started.

  Moreover, by making the oxidation unit 220 into a honeycomb shape, the oxidation catalyst 224 can be brought into contact with the mixed gas without hindering the flow of the mixed gas (while suppressing the decrease in the cross-sectional area of the flow path). Furthermore, since the oxidation unit 220 has a honeycomb shape, it is possible to avoid a situation in which the flow path of the mixed gas is blocked even when the mixed gas contains dust (dust).

  Further, as shown in FIG. 3B, the oxidation unit 220 is configured with a rod extending in a direction orthogonal to the flow direction of the mixed gas, and is provided so that the tip is arranged at the center of the flow path 202. The carrier 226 and the oxidation catalyst 228 supported on the tip of the carrier 226 may be used.

  Even with this configuration, at least a part of the mixed gas can be brought into contact with the oxidation catalyst 228, and the starting point of the progress of the oxidation reaction in the entire mixed gas can be achieved. In addition, the oxidation catalyst 228 can be brought into contact with the mixed gas without hindering the flow of the mixed gas (suppressing a decrease in the cross-sectional area of the flow path).

  As described above, the structure including the oxidation unit 220 allows the oxidation reaction of the mixed gas to proceed reliably. Although only the gas mixing section 210 does not proceed with the oxidation reaction and the temperature of the mixed gas (gasification gas X1) may not rise, the oxidation reaction of the mixed gas can be reliably performed by providing the oxidation unit 220. It is possible to increase the temperature of the mixed gas.

  In the present embodiment, the oxidation catalysts 224 and 228 (oxidation unit 220) are arranged in the vicinity of a mixed gas delivery port (not shown) in the gas mixing unit 210. Thereby, the oxidation reaction of mixed gas can be performed efficiently.

  Referring back to FIG. 2, the reforming unit 230 includes a tar reforming catalyst and a carrier that holds the tar reforming catalyst, and the temperature is increased by the oxidation unit 220 (the oxidation reaction has been performed). A tar reforming reaction in the mixed gas is promoted by bringing the tar reforming catalyst and the mixed gas into contact with each other, provided on the flow path through which the gas flows.

Here, the tar reforming catalyst includes at least Ni (hereinafter referred to as “Ni-based catalyst”). As described above, since the gasification furnace 116 performs steam gasification, the gasification gas X1 (mixed gas) generated in the gasification furnace 116 contains a large amount of water vapor (for example, about 50%). ing. Therefore, by bringing the Ni-based catalyst into contact with the mixed gas, tar and water vapor in the mixed gas can be reacted, and the tar is converted into hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ) And methane (CH ₄ ).

  In this way, tar can be removed from the gasification gas X1, and the gasification gas X2 from which the tar has been removed is sent to the purification apparatus 300 at the subsequent stage.

  As described above, according to the tar reforming apparatus 200 according to the present embodiment, the configuration including the gas mixing unit 210 can mix the gasified gas X1 and the oxidizing agent without generating a flame. In addition, the structure including the oxidation unit 220 can reliably perform the oxidation reaction of the mixed gas, and the temperature of the mixed gas can be raised to the activation temperature of the tar reforming catalyst of the reforming unit 230. . Thereby, tar can be efficiently removed in the reforming unit 230.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above embodiment, the case where the gas mixing unit 210 is configured with an ejector has been described as an example. However, the configuration of the gas mixing unit 210 is limited as long as the mixed gas can be generated without generating a portion in which the oxygen concentration is equal to or higher than a predetermined concentration in the mixed gas, that is, without generating a flame. Absent.

  Moreover, in the said embodiment, the case where the division | segmentation number of the flow path 202 by the support | carrier 222 was eight was described as an example. However, the number of divisions of the flow path 202 by the carrier 222 is not limited and may be two or more.

  Moreover, in the said embodiment, the catalyst containing at least Ni was mentioned as an example and demonstrated as a tar reforming catalyst. However, the material of the tar reforming catalyst is not limited as long as the tar in the mixed gas can be reformed and removed. For example, an oxide or carbonate of one or more elements selected from the group of Ca, Mg, Fe, and Si, for example, natural ore such as dolomite, olivine, limonite, limestone as a tar reforming catalyst It may be used. That is, a tar reforming catalyst containing one or more selected from the group consisting of Ca, Mg, Fe, and Si may be employed.

  INDUSTRIAL APPLICATION This invention can be utilized for the tar reforming apparatus which reforms the tar in gasification gas which gasifies a gasification raw material and produces | generates gasification gas.

200 Tar reformer 210 Gas mixing unit 220 Oxidation unit 230 Reform unit

Claims (2)

And oxidation unit that holds the oxidation catalyst containing Pt,
A reforming unit that holds a tar reforming catalyst including one or more selected from the group of Ni, Ca, Mg, Fe, and Si, and is provided downstream of the oxidation unit;
Supply at least oxygen-containing oxidant only to the upstream side of the oxidation unit, mix the oxidant and gasification gas, and mix without generating a portion that exceeds the lower limit of the oxygen concentration at which a flame is generated. A gas mixing section for generating gas and delivering the mixed gas;
A tar reforming apparatus comprising:   The tar reforming apparatus according to claim 1, wherein the gas mixing unit is an ejector.

Images