JP2007099927A - Tar cracking system and cracking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tar cracking system and a cracking method capable of effectively cracking tar while maintaining the tar-cracking in an efficient state by controlling the properties of a gas for gasification introduced into a tar cracking facility. <P>SOLUTION: This tar cracking system has a reactor 3 comprising a catalyst layer 3a accepting the gas for gasification which is gasified by a gasification facility 1 and dusted and cracking tar contained in the gas for gasification. The tar cracking system has also: a temperature detector T for measuring the temperature of the gas for gasification in the reactor 3; and a calculation controlling part C for comparing the temperature measured by the temperature detector T with a set temperature set beforehand and for ordering the temperature-elevating or -lowering in order to bring the temperature of the gas for gasfication introduced into the reactor 3 close to the set temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tar cracking system and a tar cracking method, and more specifically, includes a catalyst layer that receives a gasified gas that has been gasified and removed by a gasification facility and decomposes a tar content contained in the gasified gas. The present invention relates to a tar cracking system having a reactor and a tar cracking method.

  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, the gasification gas generated from the gasification facility 1 is collected by the high-temperature dust collection facility 2, and after the dust in the gasification gas is removed, the tar decomposition catalyst layer 3a. Is introduced into a tar decomposition facility 3, which is a reactor equipped with gas, and the tar content in the gasification gas is decomposed, and then the gasification gas is cooled by the gas cooling facility 4, and a low-temperature dust collection facility (not shown), etc. To be further detoxified (for example, Patent Document 1).

JP-A-11-21565

  However, the above prior art introduces the gas decomposition gas temperature and moisture content into the tar decomposition facility 3 without any control, and allows the tar decomposition in the tar decomposition facility 3 to be performed in an efficient state at all times. However, depending on the state of the gasification gas, problems such as significant deterioration of the function of the tar decomposition catalyst may occur. That is, when the temperature of the gasification gas decreases during operation, the catalyst function may be greatly deteriorated due to the deposition of carbon on the surface of the tar decomposition catalyst or the chemical adsorption of sulfur. Further, when a metal-containing catalyst such as nickel is used as the tar decomposition catalyst, a metal such as nickel may surface on the catalyst or agglomerate (sinter), and both deteriorate the catalyst function.

  In addition, when the gasification process by the gasification facility is completed (at the time of start-up), air flows in, so the carbon deposited on the catalyst surface (generally, carbon deposits on the catalyst surface with use) burns. As a result, the temperature may rise, and as a result, deterioration of the catalyst may progress or the internal structure of the tar decomposition facility may be damaged.

  In addition, when the catalyst is nickel-based, the effective temperature range is 700 to 850 ° C. (800 to 850 ° C. when the gasification gas contains several hundred ppm of S-containing gas such as hydrogen sulfide). However, if hydrocarbon gas such as ethylene or ethane is contained in the gasification gas, the catalyst temperature is lowered due to the endothermic reaction by the catalyst, and the catalyst function cannot be sufficiently performed. There's a problem.

  Therefore, in view of the above-described problems of the prior art, the object of the present invention is to control the properties of the gasification gas introduced into the tar cracking equipment and effectively maintain the tar cracking state effectively. Is to provide a tar decomposition system and a tar decomposition method.

  The above-mentioned subject is achieved by the invention described in each claim. That is, the characteristic configuration of the tar decomposition system according to the present invention is a reaction including a catalyst layer that receives a gasified gas that has been gasified and removed by a gasification facility and decomposes a tar content contained in the gasified gas. A temperature detector for measuring the temperature of the gasification gas in the reactor, and the measurement result of the temperature detector is compared with a preset set temperature and introduced into the reactor. And an arithmetic control unit that issues a temperature increase or decrease command so that the temperature of the gasification gas approaches the set temperature.

  According to this configuration, the temperature of the gasification gas brought into contact with the tar decomposition catalyst layer can be always properly controlled and maintained, so that deterioration of the catalyst function can be surely prevented and the catalyst function is maintained in an efficient state. The tar content in the gasification gas can be decomposed efficiently.

  As a result, it is possible to provide a tar decomposition system capable of effectively decomposing tar by controlling the properties of the gasification gas introduced into the tar decomposition facility and maintaining the catalytic function of the reactor in an efficient state. It was.

  A moisture detector for measuring moisture in the gasification gas is provided downstream of the reactor, and the calculation control unit compares the measurement result of the moisture detector with a preset moisture content, When the amount of water in the gasification gas is small, it is preferable to give an instruction to increase the amount of water so that the amount of water in the gasification gas introduced into the reactor approaches the set amount of water.

  According to this configuration, the amount of water in the gasification gas can be easily adjusted without requiring particularly complicated equipment, and the tar decomposition can be maintained efficiently.

  The temperature detector is provided in the catalyst layer or downstream of the catalyst layer, and raises the temperature of the gasification gas introduced into the reactor by introducing air or oxygen into the gasification gas. The temperature of the gasification gas is preferably lowered by introducing steam or water into the gasification gas.

  According to this configuration, it is possible to accurately grasp the reaction state in the catalyst layer, it is possible to quickly cope with the state of the catalyst, and it is possible to maintain the high reaction efficiency of the catalyst without requiring special equipment.

  It is preferable to increase the moisture in the gasification gas introduced into the reactor by introducing steam or water into the gasification gas.

  According to this configuration, it is very easy to increase the moisture in the gasification gas, and the properties of the gasification gas can be quickly brought into a preferable state.

  When the gasification process is lowered, it is preferable that the calculation control unit has a command for discharging the catalyst in the reactor from the reactor and setting the discharged catalyst in a non-oxidizing atmosphere.

  According to this configuration, the gasification process can be quickly brought down, the preparation for the next process can be promptly handled, the temperature of the catalyst can be lowered efficiently, and combustion on the surface of the catalyst can be ensured. Can be prevented.

  Moreover, the characteristic structure of the tar decomposition method according to the present invention is a reaction comprising a catalyst layer for receiving a gasified gas that has been gasified and removed by a gasification facility and that decomposes a tar content contained in the gasified gas. In the method of decomposing tar in the gasification gas by a vessel, the temperature of the gasification gas in the reactor is measured by a temperature detector, and the temperature measurement result is compared with a preset set temperature and The purpose is to issue a temperature increase or decrease command so that the temperature of the gasification gas introduced into the reactor approaches the set temperature.

  According to this configuration, it is possible to provide a tar decomposition method capable of effectively decomposing tar by controlling the properties of the gasification gas introduced into the tar decomposition facility and maintaining the tar decomposition efficiently. .

  The moisture detector provided on the downstream side of the reactor measures moisture in the gasification gas, compares the measurement result of the moisture amount with a preset set moisture amount, and the moisture amount in the gasification gas When the amount of water is small, it is preferable to give an instruction to increase the amount of water so that the amount of water in the gasification gas introduced into the reactor approaches the set amount of water.

  According to this configuration, the amount of water in the gasification gas can be easily adjusted, and the tar decomposition can be maintained efficiently.

  The temperature detector is provided in the catalyst layer or downstream of the catalyst layer, and the temperature of the gasification gas introduced into the reactor is increased by introducing air or oxygen into the gasification gas. The temperature of the gasification gas is preferably lowered by introducing steam or water into the gasification gas.

  According to this configuration, it is possible to accurately grasp the reaction state in the catalyst layer, it is possible to quickly cope with the state of the catalyst, and the high reaction efficiency of the catalyst can be maintained.

  It is preferable to increase the moisture in the gasification gas introduced into the reactor by introducing steam or water into the gasification gas.

  According to this structure, the property of gasification gas can be made into a favorable state rapidly.

  When the gasification process is lowered, it is preferable that a command for discharging the catalyst in the reactor is issued from the reactor and that the discharged catalyst is in a non-oxidizing atmosphere.

  According to this configuration, the gasification process can be quickly lowered, the preparation for the next step can be promptly handled, and the temperature of the catalyst can be lowered efficiently.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic flow of a tar decomposition system according to an embodiment of the present invention. In addition, the same number is attached | subjected to the structure which has the same function as a prior art.

  This tar cracking system is a high-temperature dust collection facility 2 composed of a ceramic filter or the like using gasified gas (about 800 to 900 ° C.) generated from a gasification facility 1 such as a fluidized bed gasification furnace and a circulating fluidized bed gasification furnace. In this case, dust and the like in the gasified gas are collected and removed.

  Next, the dusted gasified gas is introduced into the tar decomposition facility 3 which is a reactor having the tar decomposition catalyst layer 3a through the pipe 5, and when the tar in the gasification gas is decomposed, the gas cooling facility 4 It is the same as in the prior art in that it is fed to the water, cooled, sent to a low-temperature dust collection facility (not shown), etc., and appropriately charged with a chemical, neutralized, and rendered harmless. The catalyst of the tar decomposition catalyst layer 3a is not limited as long as tar is decomposed efficiently, but it is particularly preferable to use a mixture of dolomite or lightly burned dolomite and nickel or the like because decomposition efficiency is good.

  In the case of the tar decomposition system according to the present embodiment, the temperature inside the tar decomposition facility 3 is constantly measured by a thermometer T that is a temperature detector, and the measurement result is transmitted to an arithmetic control unit C including a computer or the like. The The arithmetic control unit C performs comparison with a preset temperature.

When the temperature in the tar decomposition facility 3 is lower than the set temperature, an opening command is issued from the arithmetic control unit C to the air / oxygen control valve 6, and the air A or oxygen O ₂ is supplied to the pipe 5 through the nozzle 7. Be sent. The gasified gas is partially combusted by the supplied air A or oxygen O ₂ , and the temperature of the gasified gas containing tar or the temperature of the tar decomposition catalyst is raised so that the catalytic function can be properly maintained. To do.

Conversely, when the temperature at the tar decomposition facility 3 is higher than the set temperature, an opening command is issued from the arithmetic control unit C to the steam amount adjusting valve 8, and the steam S is sent to the pipe 5 through the nozzle 9. Thus, the temperature of the gasification gas introduced into the catalyst layer 3a is lowered so that the catalyst function can be properly maintained. These air / oxygen control valve 6 for supplying air A or oxygen O ₂ as appropriate, and the steam amount control valve 8 for supplying steam S as appropriate, raise or lower the temperature of the catalyst layer 3a to approach the set temperature. This corresponds to the adjusting mechanism.

  Further, the steam amount adjustment valve 8 is simultaneously adjusted and controlled by moisture in the gasification gas. That is, the amount of water contained in the gasification gas decomposed from tar and discharged from the tar decomposition facility 3 is measured by the moisture analyzer 10 which is a moisture detector provided in the middle of the pipe 11, and the measurement result is calculated. It is transmitted to the control unit C. The calculation control unit C compares the measurement result obtained by the moisture analyzer 10 with a preset moisture value. When the moisture amount is low, the calculation control unit C controls the steam amount control valve 8 so that the moisture amount is appropriate. Command to open.

  Further, when the gasification process is lowered, the operation control unit C commands the opening of the catalyst extraction valve 12, and the catalyst of the tar decomposition facility 3 is extracted and discharged to the catalyst storage tank 13, and is supplied to the catalyst regeneration process. It can be so. If it does in this way, falling of gasification processing will be completed quickly and it can cope with preparations for the next process quickly. An inert gas N such as nitrogen is supplied to the catalyst storage tank 13 to effectively lower the catalyst temperature in a non-oxidizing atmosphere and prevent combustion on the catalyst surface.

  As described above, according to the present embodiment, the properties of the gasification gas introduced into the tar decomposition facility can be appropriately controlled, and the tar decomposition can be constantly maintained in an efficient state.

[Another embodiment]
(1) In the above embodiment, the gasification facility may be a gasification melting furnace or a carbonization / dry distillation facility, and is not particularly limited.
(2) In the above embodiment, the thermometer T for measuring the internal temperature of the tar decomposition facility 3 has been described with reference to the example provided in the catalyst layer 3a. However, instead of this, the thermometer T is replaced with the catalyst layer 3a. You may provide in an exit side. However, if a thermometer is provided not only in the catalyst layer but also on the outlet side of the catalyst layer, hydrocarbon gases such as ethane and ethylene contained in the gasification gas are decomposed by the catalyst in an endothermic reaction, and the catalyst temperature decreases. When this occurs, it is preferable that the catalyst temperature can be increased.
(3) Furthermore, in order to detect the state of the tar decomposition reaction, the temperature of the gasification gas at the inlet and outlet sides of the tar decomposition facility may be measured, and the measurement may be performed based on the measurement result. That is, the tar decomposition reaction is an endothermic reaction, and the temperature decreases with the progress of the reaction, so that a difference occurs between the temperatures on the inlet and outlet sides. A thermometer is provided in each of the pipes 5 and 11 through which the gasification gas flows, and the temperature difference between the two is compared while transmitting the measurement result to the controller C. When the temperature difference becomes small, the catalyst temperature is set. You may make it perform the treatment to raise.
(4) As gasification gas applicable to this invention, the gasification gas etc. which were produced | generated by burning various solid fuel, industrial waste, etc. other than various organic waste are mentioned.

Schematic flowchart showing a tar decomposition system according to an embodiment of the present invention. Schematic flow diagram showing a tar decomposition system according to the prior art

Explanation of symbols

1 Gasification Equipment 3 Reactor 3a Catalyst Layer 10 Moisture Detector C Operation Control Unit T Temperature Detector

Claims (10)

In a tar decomposition system having a reactor that receives a gasified gas that has been gasified and removed by a gasification facility and has a catalyst layer that decomposes a tar content contained in the gasified gas, the gas in the reactor A temperature detector for measuring the temperature of the gasification gas is compared with the measurement result of the temperature detector and a preset set temperature, and the temperature of the gasification gas introduced into the reactor is increased so as to approach the preset temperature. A tar decomposition system, comprising: an arithmetic control unit that issues a temperature or temperature lowering command. A moisture detector for measuring moisture in the gasification gas is provided downstream of the reactor, and the calculation control unit compares the measurement result of the moisture detector with a preset moisture content, The tar decomposition system according to claim 1, wherein when the amount of moisture in the gasification gas is small, an instruction to increase the amount of moisture is issued so that the moisture in the gasification gas introduced into the reactor approaches the set moisture amount. The temperature detector is provided in the catalyst layer or downstream of the catalyst layer, and raises the temperature of the gasification gas introduced into the reactor by introducing air or oxygen into the gasification gas. The tar decomposition system according to claim 1 or 2, wherein the temperature of the gasification gas is lowered by introducing steam or water into the gasification gas. The tar decomposition system according to claim 2 or 3, wherein the moisture in the gasification gas introduced into the reactor is increased by introducing steam or water into the gasification gas. 5. The apparatus according to claim 1, further comprising: a command for discharging the catalyst in the reactor from the reactor and making the discharged catalyst in a non-oxidizing atmosphere when the gasification process is lowered. A tar decomposition system according to claim 1. Method for decomposing tar in gasified gas by a reactor having a catalyst layer for receiving a gasified gas that has been gasified and removed by a gasification facility and decomposing tar content in the gasified gas The temperature of the gasification gas in the reactor is measured by a temperature detector, the temperature measurement result is compared with a preset temperature, and the temperature of the gasification gas introduced into the reactor is set to a preset temperature. A tar decomposition method characterized by issuing a temperature increase or decrease command so as to approach The moisture detector provided on the downstream side of the reactor measures moisture in the gasification gas, compares the measurement result of the moisture amount with a preset set moisture amount, and the moisture amount in the gasification gas The tar decomposition method according to claim 6, wherein when the amount of water is small, an instruction to increase the amount of water is given so that the water in the gasification gas introduced into the reactor approaches the set amount of water. The temperature detector is provided in the catalyst layer or downstream of the catalyst layer, and the temperature of the gasification gas introduced into the reactor is increased by introducing air or oxygen into the gasification gas. The tar decomposition method according to claim 6 or 7, wherein the temperature of the gasification gas is lowered by introducing steam or water into the gasification gas. The tar decomposition method according to claim 7 or 8, wherein the moisture in the gasification gas introduced into the reactor is increased by introducing steam or water into the gasification gas. The tar decomposition method according to any one of claims 6 to 9, wherein when the gasification treatment is stopped, a command for discharging the catalyst in the reactor is issued from the reactor, and the discharged catalyst is set to a non-oxidizing atmosphere.

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