JP2009280633A - Method and apparatus for cracking tar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cracking tar in which a temperature of a catalyst is controlled within a range of a reaction temperature by dispersing an oxidizing agent, and an apparatus for cracking tar. <P>SOLUTION: This method for cracking tar includes cracking tar contained in a gasified gas as an inflammable gas by use of a metal catalyst, wherein by supplying the oxidizing agent via a dispersion layer set in a preceding stage of the catalyst, the temperature of the catalyst is controlled within the range of the reaction temperature of the catalyst. Furthermore, by oxidizing the gas for gasification on the catalyst by use of the oxidizing agent, the temperature of the catalyst is controlled within the range of the reaction temperature of the catalyst. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tar decomposing method and a tar decomposing apparatus for decomposing a tar content contained in a combustible gas gas by a catalyst.

  Gasification technology has attracted attention as a technology for converting energy efficiently from waste (organic waste) containing organic matter such as wood chips and sewage sludge and biomass fuel. It is possible to generate power by burning the gas generated by gasification in an internal combustion engine such as a gas engine or a gas turbine, and the power generation efficiency is to directly burn fuel to generate steam. It has a feature of higher efficiency by a boiler power generation system that generates power by using a power source (Patent Document 1).

  However, the generated gas generated from the gasification equipment contains dust, tar, and other harmful corrosive substances / contaminants. If it is directly input to the power generation equipment such as a gas engine, the combustion equipment, piping, nozzles, Other problems such as clogging and corrosion occur.

  Therefore, the gasification gas generated from the gasification facility needs to be detoxified. That is, as shown in FIG. 2 of Patent Document 1, the gasification gas generated from the gasification facility 1 is collected by the high-temperature dust collection facility 2, and the dust in the gasification gas is removed. It is introduced into a tar decomposition facility 3 which is a reactor equipped with a decomposition catalyst layer 3a, and the tar content in the gasification gas is decomposed. Thereafter, the gasification gas is cooled in the gas cooling facility 4, and the low-temperature dust collection facility ( (Not shown) and the like, and further detoxified (for example, Patent Document 1).

  A tar decomposition system having a reactor that receives a gasified gas that has been gasified and removed by a gasification facility and that has a catalyst layer that decomposes the tar content contained in the gasified gas. A temperature detector for measuring the temperature of the gasification gas of the gas, and the measurement result of the temperature detector and a preset set temperature are compared, and the temperature of the gasification gas introduced into the reactor is brought close to the set temperature There is known a tar decomposition system including an arithmetic control unit that performs a temperature increase or decrease command (see Patent Document 2).

JP-A-11-21565 JP 2007-99927 A (Claim 1)

  However, in the tar decomposition system of Patent Document 2, although the temperature of the gasification gas can be brought close to a preset temperature range, air or oxygen gas for raising the temperature of the gasification gas is used as a gasification furnace. Since it was configured to supply into the piping provided between the tar decomposition facilities, a flame was generated when the gasified gas was partially burned in the piping, and soot was generated due to non-uniform combustion due to the generation of the flame. The soot adheres to the inner wall of the pipe or moves to the catalyst layer together with the gasification gas, and soot accumulates on the catalyst surface. The accumulation of soot deteriorates the function of the catalyst and the flow of the gasification gas, which causes a decrease in performance due to the drift of the gasification gas and an increase in attractive power due to an increase in pressure loss. In addition, once generated soot is extremely difficult to burn in a reducing atmosphere, the furnace must be stopped for maintenance. Even when the temperature of the gasification gas is low, combustion of the oxidant becomes incomplete, and soot generation is increased.

  Further, when the oxidizing agent is supplied to the pipe, the oxidizing agent reaches the catalyst layer in a temperature range where the combustion does not occur (less than 700 ° C.), and the catalyst is oxidized and generated heat. However, at this time, if the oxidant is not dispersed in the gasification gas and a local temperature rise occurs, the catalyst is thermally deteriorated, which is a problem.

  In addition, even when the temperature of the gasification gas at the inlet of the tar decomposition facility is high, considering the heat dissipation and reaction heat (catalyst endothermic reaction), the temperature of the gasification gas is increased rather than burning the gasification gas on the pipe and raising the temperature. It is considered better to maintain the reaction temperature of the catalyst by burning the gasification gas at a close position. However, if the oxidizing agent is supplied directly to the vicinity of the catalyst, local combustion occurs as described above, and the catalyst is thermally deteriorated.

  In addition to the tar decomposition system described in Patent Document 2, it is conceivable that the temperature of the catalyst is raised to the reaction temperature by raising the temperature with an external heating reactor or directly with a burner. However, the external heat reactor is not preferable because it has a complicated structure and uses expensive heat-resistant metal piping, which greatly increases equipment costs and maintenance costs. Further, the method of directly raising the temperature of the catalyst with a burner is not preferable because flame and soot are generated as in the case of Patent Document 2 described above.

  Accordingly, the present invention has been made in view of the above-mentioned problems and situations of the prior art, and its purpose is to disperse an oxidizing agent, thereby controlling the temperature of the catalyst within the reaction temperature range. It is to provide a method and a tar decomposition apparatus thereof.

The above-mentioned subject is achieved by the invention described in each claim. That is, the tar decomposition method according to the present invention is:
A tar decomposition method in which a tar content contained in a gasified gas of a combustible gas is decomposed by a metal catalyst,
The temperature of the catalyst is controlled within the reaction temperature range of the catalyst by supplying an oxidizing agent through a dispersion layer provided in the preceding stage of the catalyst.

  As an embodiment of the above method, the gasification gas is oxidized on the catalyst by the oxidizing agent, and the temperature of the catalyst is controlled within a reaction temperature range of the catalyst.

  According to this configuration, the supplied oxidant is mixed with the gasification gas while being dispersed in the dispersion layer, suppressing combustion of the gasification gas, reaching the catalyst layer, and the oxidant with respect to the catalyst layer. Promotes a uniform oxidation reaction. Further, the reaction temperature necessary for the tar reforming reaction can be maintained, and thermal deterioration of the catalyst due to local oxidation and heat generation can be suppressed.

  As another embodiment of the above method, in addition to or in addition to the oxidation reaction of the catalyst, the gasification gas is uniformly burned by the oxidizing agent, and the temperature of the catalyst is controlled within the reaction temperature range of the catalyst. Features.

  According to this configuration, the supplied oxidant is dispersed in the dispersion layer and reacts with the gasification gas to promote uniform combustion without generating a flame. Therefore, no soot is generated due to non-uniform combustion accompanied by a flame. Further, the catalyst temperature can be controlled within the reaction temperature range by increasing the temperature of the gasified gas that is uniformly combusted. Since the oxidizing agent is suitably dispersed, local temperature rise is suppressed, and thermal degradation of the catalyst does not occur.

  Further, in the above method, it is preferable to control the supply amount of the oxidant or the flow rate which is the supply speed. The dispersion state of the oxidant can be controlled by controlling the supply amount of the oxidant or the flow rate that is the supply speed thereof. For example, when the flow rate is increased, dispersibility is improved, and mixing with the gasification gas is improved. Further, due to the improved dispersibility, no flame is generated and no soot is generated when the gasified gas is burned. Moreover, it is preferable to make the temperature of an oxidizing agent normal temperature or more. This is because the oxidation reaction and the combustion reaction are suitably performed.

In addition, the tar decomposition apparatus of the present invention is
A tar decomposition apparatus that decomposes a tar content contained in a combustible gas gas by a catalyst,
A metal-based catalyst layer for decomposing tar provided inside the tar decomposition apparatus;
A catalyst layer temperature measuring means for measuring the temperature of the metal catalyst layer;
A dispersion layer provided in front of the metal-based catalyst layer;
An oxidant supply means for supplying the oxidant;
Control means for controlling the flow rate of the oxidant supplied from the oxidant supply means via the dispersion layer so that the temperature of the catalyst layer measured by the catalyst layer temperature measurement means falls within the reaction temperature range of the catalyst; It is characterized by having.

  According to this configuration, the flow rate of the oxidant supplied from the oxidant supply means via the dispersion layer can be controlled, and thus the temperature of the metal catalyst layer can be maintained within the reaction temperature range. The supplied oxidant is mixed with the gasification gas while being dispersed in the dispersion layer to suppress the combustion of the gasification gas and reach the catalyst layer so that the oxidant is uniformly oxidized with respect to the catalyst layer. Promote. Further, the reaction temperature necessary for the tar reforming reaction can be maintained, and thermal deterioration of the catalyst due to local oxidation and heat generation can be suppressed. As another or additional action, the supplied oxidant is dispersed in the dispersion layer and reacts with the gasification gas to promote uniform combustion. Therefore, no soot is generated due to non-uniform combustion accompanied by a flame. Further, the catalyst temperature can be controlled within the reaction temperature range by increasing the temperature of the gasified gas that is uniformly combusted. Since the oxidizing agent is suitably dispersed, local temperature rise is suppressed, and thermal degradation of the catalyst does not occur.

As one embodiment of the present invention,
A dispersion layer temperature measuring means for measuring the temperature of the dispersion layer;
The control means sets the temperature of the catalyst within the reaction temperature range of the catalyst based on the temperature of the dispersion layer measured by the dispersion layer temperature measuring means and the temperature of the catalyst layer measured by the catalyst layer temperature measuring means. Thus, the flow rate of the oxidizing agent is controlled.

  According to this configuration, since the flow rate of the oxidant can be controlled based on the temperature of the catalyst layer and the temperature of the dispersion layer, it is effective even when the variation in the amount of gasification gas inflow is large. The temperature of the metal catalyst layer can be maintained within the reaction temperature range, and the local oxidation reaction of the catalyst and the generation of soot can be more suitably suppressed.

  Moreover, as an arrangement | positioning of an oxidizing agent supply means, arrange | positioning upstream or inside a dispersion layer is mentioned.

  Further, the dispersion layer is characterized in that the storage means is filled with a dispersant of a heat resistant material. The dispersant constituting the dispersion layer has heat resistance, and examples thereof include ceramic, alumina, silica, silica / alumina, and clay mineral. Examples of the shape of the dispersant include various shapes such as balls, rings, and pellets, and the size is preferably about 3 to 25 mm in outer diameter. The storage means has heat resistance, and its shape is exemplified by various shapes such as a columnar shape, a box shape, a spherical shape, and a honeycomb shape, and these may be a single member or a plurality of members.

  Moreover, gasification gas is gasified, for example, biomass fuel, coal, coke, waste oil, and other organic compounds. Examples of the gasification method include methods such as thermal decomposition, partial oxidation, and steam reforming. In this invention, it is preferable that the temperature of gasification gas is 500 degreeC or more and 900 degrees C or less gas temperature. This is because if the temperature is lower than 500 ° C., the metal catalyst is difficult to oxidize and burn.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic flow of a tar decomposing apparatus according to an embodiment of the present invention.

  The gasification facility 1 includes, for example, a fluidized bed gasification furnace, a circulating fluidized bed gasification furnace, and the like. For example, the gasification facility 1 gasifies biomass fuel, coal, coke, waste oil, and other organic compounds by a method such as thermal decomposition to generate gasified gas.

  The tar decomposition apparatus 2 treats the tar component in the gasification gas (about 800 to 900 ° C.) generated by the gasification facility 1 with a metal catalyst. The tar decomposing apparatus 2 includes a reactor 21 having a metal catalyst layer, and a disperser 22 (corresponding to storage means) having a disperse layer installed in the previous stage of the reactor 21.

Examples of the metal-based catalyst include a single-piece structure or a plurality of combination structures selected from nickel-based catalysts, cobalt-based catalysts, iron-based catalysts, chromium-based catalysts, and copper-based catalysts. Examples of the nickel-based catalyst include Ni / Al ₂ O ₃ , Ni / MgO, Ni / MgO · CaO, and the like, and a composite oxide reforming catalyst containing nickel, magnesia and calcia is more preferable. The reaction temperature of these metal-based catalysts is lower than the deterioration temperature of the metal-based catalyst, for example, in the range of 700 ° C. or higher and lower than 850 ° C., and preferably in the range of 750 ° C. or higher and lower than 800 ° C.

  The dispersant constituting the dispersion layer has heat resistance, and examples thereof include ceramic, alumina, silica, silica / alumina, and clay mineral. Examples of the shape of the dispersant include various shapes such as balls, rings, and pellets, and the size is preferably about 3 to 25 mm in outer diameter. The disperser 22 has heat resistance, and its shape is exemplified by various shapes such as a columnar shape, a box shape, a spherical shape, and a honeycomb shape, and these may be a single body or a plurality of shapes.

  Although not shown in FIG. 1, dust and the like in the gasified gas are collected by a high-temperature dust collection facility between the gasification facility 1 and the tar decomposition device 2 via a high-temperature dust collection facility composed of a ceramic filter or the like. You may comprise so that dust may be removed.

  In the gasification gas introduced into the tar decomposition apparatus 2, the tar in the gasification gas is decomposed by the metal catalyst. Thereafter, the gasification gas is supplied to the gas purification facility 3 to purify the gasification gas, and is supplied to the gas utilization facility 4 to be provided for combustion or the like. The gas purification equipment 3 can comprise, for example, a gas cooling device, a low-temperature dust collector such as a bag filter, a wet gas purification equipment, or the like alone or in combination thereof. The gas utilization facility 4 includes, for example, a combustion facility such as a boiler, a power generation facility such as a gas turbine and a gas engine, or a combination thereof.

(Embodiment 1)
A characteristic configuration of the tar decomposition facility 2 of Embodiment 1 will be described below. The reactor 21 having a metal catalyst layer is provided with a catalyst temperature measuring device 24 for measuring the temperature of the metal catalyst. The temperature detection part of the catalyst temperature measuring device 24 is not particularly limited as long as it is a position where the temperature of the catalyst is detected. Examples thereof include a position close to each other, a catalyst layer wall surface, the inside of the catalyst layer, a position in direct contact with the catalyst, and the like. Further, the catalyst temperature measuring device 24 is not limited to one, and a plurality of catalyst temperature measuring devices 24 may be installed. Further, the catalyst temperature measuring device 24 may be installed at the upper part of the catalyst layer on the gasification gas inlet side, or may be installed at the middle part or the lower part. More preferably. The temperature state and temperature distribution of the catalyst can be accurately obtained from a plurality of measured temperature data.

  A dispersion layer temperature measuring device 25 for measuring the temperature of the dispersion layer is installed in the dispersion device 22 having the dispersion layer. The temperature detection portion of the dispersion layer temperature measuring device 25 is not particularly limited as long as it is a position for detecting the temperature of the dispersion layer. For example, the outer wall of the dispersion device 22, the inner wall portion of the dispersion device 22, the inside of the dispersion device 22, or the dispersion device. Examples are the position close to the layer, the inside of the dispersion layer, the position in direct contact with the dispersant, and the like. Moreover, the number of the dispersion | distribution layer temperature measuring devices 25 is not limited to one, You may install two or more. Further, the dispersion layer temperature measuring device 25 may be installed in the upper part of the dispersion layer on the gasification gas inlet side, or may be installed in the middle part or the lower part. It is more preferable to install. The temperature state and temperature distribution of the dispersion layer can be accurately obtained from a plurality of measured temperature data.

  The catalyst temperature measuring device 24 and the dispersed bed temperature measuring device 25 may be a contact thermometer or a non-contact thermometer.

  The oxidant supply means 23 includes one or a plurality of nozzles 231. The nozzle 231 has a structure that allows the oxidant to be uniformly dispersed and supplied to the dispersion layer, and is arranged as such. It is preferable that the tip of the nozzle 231 has a plurality of small holes so that the gaseous oxidant can be uniformly dispersed in the dispersion layer, and can be ejected radially. It is preferable that the density distribution of the oxidant sprayed from the nozzle 231 with respect to the dispersion layer plane is substantially uniform.

  Further, the oxidant supply means 23 includes a compressor for supplying an oxidant from a storage container (not shown) of the oxidant to the nozzle 231 at a predetermined supply amount and a flow rate, thereby generating a compressed gas. The oxidant supply means 23 includes a flow meter, a flow rate adjustment valve, a flow rate meter, and a flow rate adjustment function for adjusting the flow rate. The oxidant supply means 23 performs oxidant supply control in accordance with a command from a control device 26 described later.

  The oxidizing agent is, for example, air or oxygen-enriched air. The temperature of the oxidizing agent is preferably normal temperature or higher and 400 ° C. or lower, and more preferably normal temperature or higher and 100 ° C. or lower from the viewpoint of reducing the combustion cost for increasing the oxidizing agent temperature. A combustion apparatus (not shown) for raising the temperature of the oxidant may be disposed in front of the oxidant supply means 23, or may be provided in the oxidant supply means 23 or an oxidant storage container (not shown). Good. When air is used as the oxidant, there is no need for a storage container.

The control device 26 (corresponding to the control means) includes an oxidant supply means so that the temperature of the catalyst layer measured by the catalyst temperature measuring device 24 falls within the reaction temperature range of the catalyst (for example, 700 ° C. or higher and lower than 850 ° C.). The flow rate of the oxidant supplied by 23 is set, and the oxidant supply means 23 is commanded. For example, the control device 26 can set the flow rate of the oxidizing agent based on the temperature measured by the catalyst temperature measuring device 24. As another embodiment, the control device 26 can set the flow rate of the oxidant based on the temperature data measured by the catalyst temperature measuring instrument 24 and the temperature data measured by the dispersed bed temperature measuring instrument 25. Supply amount of the oxidizing agent is set by the specifications of the flow rate and the catalyst bed of the gasification gas, for example, gasification gas 1.0 m ³ N / h per 0.01~0.1m ³ N / h. Moreover, the set flow rate is 1-20 m / sec, for example. Examples of the control method include feedback control based on catalyst temperature data, PID control, and proportional control. The control device 26 is configured by an information processing device, firmware, a dedicated circuit, or the like. In the case of the information processing device, a program describing a control procedure, a memory for storing the program, a CPU as a calculation unit, and hardware such as a main memory Realized by cooperation with resources. Moreover, the control apparatus 26 may be interlock | cooperated with the control apparatus of the gasification equipment 1 and the tar decomposition | disassembly apparatus 2, and may function independently.

  Hereinafter, the control operation of the control device 26 will be described with reference to the operation flow of FIG. In step S1, temperature data of the catalyst layer is acquired. As the temperature data of the catalyst layer, the temperature data measured by the catalyst temperature measuring device 24 is transmitted to the control device 26 and stored in a memory (not shown). Next, the control device 26 determines whether or not the acquired temperature data of the catalyst layer is included in the reaction temperature range of the catalyst (for example, 750 ° C. or higher and 800 ° C. or lower) (step S2).

  Next, when the temperature data of the catalyst layer is lower than the reaction temperature range of the catalyst, the control device 26 performs oxidant supply control (step S3). The control device 26 can select either air or oxygen-enriched air from among a plurality of types of oxidizers. The control device 26 sets the flow rate of the oxidant. The difference between the temperature data of the catalyst layer and the reaction temperature range of the catalyst is calculated, and the flow rate can be set according to the difference. In setting the flow velocity, the flow rate may be set according to a preset supply amount. In addition, the supply amount can be set when the flow rate is set. Moreover, the supply time of an oxidizing agent can be set. Moreover, continuous supply and intermittent supply can be selected as a supply method. A supply command is transmitted to the oxidant supply means 23 together with the type, flow rate (or supply amount and flow rate), and supply time of the oxidant set by the control device 26 (step S3).

  For example, the flow rate is preferably 1.5 m / sec or more, more preferably 5.0 m / sec or more, and particularly preferably 10.0 m / sec or more. Uniform combustion at the time of self-combustion of the gasified gas and the oxidant can be promoted by setting the flow rate at a higher speed and uniform dispersion by the dispersion layer. Further, uniform mixing with the gasification gas is promoted, and uniform oxidation reaction on the catalyst can be promoted.

  The oxidant supply means 23 sucks the commanded oxidant, and supplies the oxidant to the supply nozzle 231 according to the command flow rate (or supply amount and flow rate) and the supply time.

The oxidant injected at high speed from the nozzle 231 is fed into the dispersion layer, and is uniformly mixed with the gasification gas by the dispersion layer. At this time, since the oxidizing agent is injected at a high speed, the combustion of the gasifying gas is suppressed by mixing the gasifying gas and the oxidizing agent. And the oxidizing agent mixed with gasification gas is supplied to a catalyst layer, and it can accelerate | stimulate the uniform oxidation reaction of a catalyst. The reaction formula of the oxidation reaction is shown below.
(Formula 1) Ni + 1 / 2O ₂ → NiO (exothermic reaction) (1)
(Formula 2) NiO + H ₂ → Ni + H ₂ O (2)
(Formula 3) NiO + CO → Ni + CO ₂ (3)

Thus, the reaction temperature necessary for the tar reforming reaction can be maintained by the heat generated by the uniform oxidation reaction of the catalyst. Since the tar reforming reaction is an endothermic reaction, the catalyst temperature decreases, but the catalyst can be effectively heated by the uniform oxidation reaction of the catalyst. Moreover, the local oxidation reaction (heat generation) of the catalyst can be suppressed, and the thermal deterioration of the catalyst can be effectively suppressed. The reaction formula of the tar reforming reaction is shown below.
(Formula 4) CmHn + mH ₂ O → mCO + (m + n / 2) H ₂ (endothermic reaction) (4)
(Formula 5) CmHn + mCO ₂ → ₂ mCO + n / 2H ₂ (endothermic reaction) (5)

  Due to the exothermic heat of the oxidation reaction of the catalyst, the temperature of the catalyst rises. This increased temperature is measured by the catalyst temperature measuring device 24 and transmitted to the control device 26. The control device 26 repeats the operations from step S1 to step S3 to perform supply control of the oxidant. If the temperature data of the catalyst is stably shifted within the reaction temperature range, it is possible to control to stop the supply of the oxidizing agent. Further, when the temperature data of the catalyst falls below the lower limit value of the reaction temperature range, the oxidant supply control can be performed again. Further, when the temperature data of the catalyst greatly varies within the reaction temperature range, the flow rate (or other parameter) of the oxidant can be controlled as needed so that the temperature data becomes stable. Therefore, the catalyst layer has little temperature unevenness, and the catalyst performance can be effectively maintained.

Below, the case where gasification gas temperature is high temperature (for example, 800 degreeC or more) is demonstrated. The operation flow is the same as in FIG. When the gasification gas temperature is, for example, 800 ° C. or higher, self-combustion occurs when the oxidizing agent and the gasification gas come into contact with each other. In this self-combustion, non-uniform combustion (combustion reaction) accompanied by a flame is caused, and when a flame is generated, soot is generated, resulting in problems as discussed above. The reaction equations of the gasification gas combustion reaction (Formulas 6 and 7) and soot generation reaction (Formulas 8 and 9) are shown below.
(Formula 6) H ₂ + 1 / 2O ₂ → H ₂ O (exothermic reaction) (6)
(Formula 7) CmHn + O ₂ → mCO ₂ + n / 2H ₂ O (exothermic reaction) (7)
(Formula 8) 2CO → CO ₂ + C (8)
(Formula 9) CmHn → mC + n / 2H ₂ (9)

  In the present embodiment, even when the temperature of the gasification gas is 800 ° C. or higher, the oxidant is injected at a high speed, and the gasification gas in contact with the oxidant in the dispersion layer promotes uniform combustion without a flame. Yes. There is no flame, so no soot is generated. Therefore, in this embodiment, generation | occurrence | production of a flame and soot can be suppressed effectively.

  In the above operation flow, the control device 26 has been described as being configured to perform supply control of the oxidant based on the temperature data measured by the catalyst temperature measuring device 24, but is not limited thereto. For example, based on the temperature data measured by the dispersion layer temperature measuring device 25, supply control (for example, flow rate) of the oxidant can be performed. Further, based on the temperature data measured by the catalyst temperature measuring device 24 and the temperature data measured by the dispersed bed temperature measuring device 25, supply control (for example, flow rate) of the oxidant can be performed.

Example 1
A gasified gas 2m ³ N / h obtained by gasifying a woody biomass fuel was collected and then introduced into a tar decomposition apparatus. In the upper part of the catalyst layer (upstream side of the gas flow), compressed air was added from the nozzle at a supply rate of 0.15 m ³ N / h. At that time, (1) visually check for the presence or absence of a flame (view through the viewing window), (2) the temperature of the gasification gas after the addition of air (temperature of the gasification gas inside the dispersion layer), the temperature of the catalyst layer (thermocouple) Measurement), (3) Evaluation of soot generation degree (confirmation by sampling of gasification gas) and the like. As conditions, the effect of air addition speed (flow rate), presence / absence of a dispersion layer, and temperature of the added air were confirmed.

(Experimental conditions)
Gasification gas temperature: 700 ° C. (temperature upstream of the air addition stage)
Air temperature: Normal temperature, 350 ° C
Air flow rate: 0.5, 1.5, 5.0, 10.0 m / sec
Dispersion layer: Ceramic ball layer

The experimental results are shown in Table 1.

  When the flow rate of the additive air is slow, 0.5 and 1.5 m / sec, the generation of flame is observed at the tip of the nozzle due to the combustion of gasified gas. And the temperature of the gasification gas increased. On the other hand, when the flow rate of the additive air is high, 5.0, 10.0 m / sec, no flame or soot is observed at the nozzle tip, and the increase in the temperature of the catalyst layer is observed. It was confirmed that combustion (oxidation reaction) in the catalyst layer was promoted.

  In addition, when the added air temperature was 350 ° C., the gasified gas tended to burn easily, but catalytic combustion was promoted by increasing the air flow rate.

  Furthermore, due to the presence of the ceramic ball dispersion layer, the added air was dispersed (dispersion effect), and catalytic combustion was promoted.

(Other embodiments)
(1) The present invention is not limited to the case where the nozzle 231 of the oxidant supply means 23 is installed on the upstream side of the dispersion layer, and the nozzle 231 can be installed inside the dispersion layer, or the upstream side of the dispersion layer and the inside of the dispersion layer. Can be installed in both.
(2) In the above embodiment, the gasification facility may be a gasification melting furnace, a carbonization / dry distillation facility, or the like, and is not particularly limited.
(3) As gasification gas applicable to this invention, the gasification gas produced | generated by burning various solid fuel, industrial waste, etc. other than various organic wastes etc. are mentioned.

Schematic flowchart showing a tar decomposition apparatus according to an embodiment of the present invention. Operation flowchart according to one embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gasification equipment 2 Tar cracking device 21 Reactor 22 Disperser 23 Oxidant supply means 231 Nozzle 24 Catalyst temperature measuring device 25 Dispersed bed temperature measuring device 26 Control device 3 Gas purification equipment 4 Gas utilization equipment

Claims (7)

A tar decomposition method in which a tar content contained in a gasified gas of a combustible gas is decomposed by a metal catalyst,
A tar decomposition method, wherein the temperature of the catalyst is controlled within a reaction temperature range of the catalyst by supplying an oxidant through a dispersion layer provided in a preceding stage of the catalyst.   The tar decomposition method according to claim 1, wherein the gasification gas is oxidized on the catalyst by the oxidizing agent, and the temperature of the catalyst is controlled within a reaction temperature range of the catalyst.   The tar decomposition method according to claim 1 or 2, wherein the gasification gas is uniformly burned by the oxidizing agent, and the temperature of the catalyst is controlled within a reaction temperature range of the catalyst. A tar decomposition apparatus that decomposes a tar content contained in a combustible gas gas by a catalyst,
A metal-based catalyst layer for decomposing tar provided inside the tar decomposition apparatus;
A catalyst layer temperature measuring means for measuring the temperature of the metal catalyst layer;
A dispersion layer provided in front of the metal-based catalyst layer;
An oxidant supply means for supplying the oxidant;
Control means for controlling the flow rate of the oxidant supplied from the oxidant supply means via the dispersion layer so that the temperature of the catalyst layer measured by the catalyst layer temperature measurement means falls within the reaction temperature range of the catalyst; A tar decomposing apparatus. A dispersion layer temperature measuring means for measuring the temperature of the dispersion layer;
The control means sets the temperature of the catalyst within the reaction temperature range of the catalyst based on the temperature of the dispersion layer measured by the dispersion layer temperature measuring means and the temperature of the catalyst layer measured by the catalyst layer temperature measuring means. The tar decomposition apparatus according to claim 4, wherein the flow rate of the oxidizing agent is controlled.   6. The tar decomposition apparatus according to claim 4, wherein the oxidant supply means is disposed upstream of the dispersion layer. The tar decomposition apparatus according to any one of claims 4 to 6, wherein the oxidant supply means is disposed inside the dispersion layer.

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