JP2006037012A - Gasification power generation system and gasification power generation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasification power generation system capable of surely brushing off dust in dust collecting devices as well, without causing deterioration of power generation efficiency, and capable of conducting stable operation, and to provide a gasification power generation method. <P>SOLUTION: This gasification power generation system has a gasification furnace 23 for gasifying a material to be gasified by heating the material, has dust collecting means 24, 28 arranged on a downstream side of the gasification furnace 23 and purifying a produced gas generated from the gasification furnace 23, and supplies power generation equipment with the produced gas purified by the dust collecting means 24, 28, wherein the dust collecting means 24, 28 comprise filtration-type dust collectors and the system has a combustible gas supply mechanism 27 in which the combustible gas is used as a pulse jet when the dust attached to the filtration-type dust collectors is brushed off by the pulse jet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gasification power generation system and a gasification power generation method, and more specifically, a gasification furnace that heats and gasifies a gasification object, and is generated downstream from the gasification furnace and is generated from the gasification furnace. The present invention relates to a dust collecting means for purifying a generated gas, a gasification power generation system and a gasification power generation method capable of supplying the generated gas purified by the dust collection means to a power generation facility.

  Gasification power generation systems are being developed that heat and decompose organic gasified products such as biomass to gasify them and use them as fuel gas for power generation facilities (for example, Patent Document 1).

  In this gasification power generation system, for example, as shown in FIG. 2, the organic gasified product is pulverized to a predetermined size by a pulverizer 1 or the like as necessary, and the pulverized gasified product is less than a predetermined amount. It is dried by the drier 2 so as to have a water content of The dried gasified product is put into a circulating fluidized bed type gasification furnace 3 which is a kind of gasifier, and is heated and decomposed to be gasified. The circulating fluidized bed type gasification furnace 3 is adjacent to a cyclone 3a. After the material to be gasified and the heating medium (fluidized sand, etc.) are fluidized and gasified, they rise to the upper part of the gasification furnace. The generated gas and the fluid medium are separated by the cyclone 3a, and the gas generated by heating and decomposition is sent to the next process from the upper part of the cyclone 3a, but the fluid medium captured by the cyclone is placed at the lower part of the cyclone 3a. It is collected and returned to the circulating fluidized bed gasification furnace 3 for reuse. A loop seal 3b is installed at the lower part of the cyclone and the separation part of the circulating fluidized bed gasification furnace to prevent the product gas from flowing back from the furnace. In order to achieve this, nitrogen is introduced. Of course, it is conceivable to supply air instead of nitrogen. In that case, however, unburned carbon is mixed in the fluid medium, which may cause ignition, which is not preferable.

  The generated gas is removed by the ceramic filter 4 which is a high temperature dust collector. In this case, the ash and unburned components in the product gas are returned to the gasification furnace 3 again and circulated in the gasification furnace 3 to ensure a sufficient residence time, thereby contributing to the improvement of gasification efficiency. It will be. The ash is combusted and gasified in the residue gasifier 5 installed below the gasifier 3 and discharged out of the system. Air or oxygen is blown into the residue gasification furnace 5 to promote combustion.

  The product gas removed by the ceramic filter 4 is sent to a heat exchanger 6 that is a heat recovery device to be recovered. The thermal energy is sent to the boiler facility 9 and used effectively.

  When the heat-recovered product gas contains an acid gas such as sulfur oxide or hydrogen chloride, it is sent to the sodium hydrogen carbonate blowing device 7 as a chemical charging device to neutralize and remove the acid components in the product gas. And purified. The reaction product in the neutralized product gas is removed by a low-temperature dust collector 8 such as a bag filter, which is a dust collecting means, and taken out of the system. The purified gas from which the reaction products have been removed by the low temperature dust collector 8 is supplied to a gas engine, a gas turbine, etc. 10 and used for power generation. Further, the fuel exhaust gas from the gas engine and the gas turbine is supplied to the boiler facility 9 for heat recovery.

In the gasification power generation system described above, dust removal and cleaning of the ceramic filter 4 that is a high-temperature dust collector and the bag filter 8 that is a low-temperature dust collector are mainly performed by spraying nitrogen by a pulse jet method to wipe off the attached dust. I am doing so.
JP 2003-171672 A

  However, since the above prior art is performed by blowing nitrogen from a nitrogen gas production facility installed in the system for dust removal of the dust collector (filter type dust collector) (pulse jet method), When the gas generated from the gasification furnace is burned and used, the combustion gas is diluted, and there is a problem that the calorific value of the generated gas is reduced. Moreover, since dust removal and cleaning of the dust collector are frequently performed during operation without stopping the system, the amount of nitrogen blown is never small, and as a result, the power generation efficiency of the downstream power generation equipment is reduced. It is supposed to be lowered. In addition, when using a circulating fluidized bed gasifier, a loop seal is installed at the lower part of the cyclone and the separation part of the circulating fluidized bed gasifier, and nitrogen gas is introduced there. The combustion gas generated by the combustion of the gasified product is diluted. Further, when air is used instead of nitrogen for the loop seal portion, unburned carbon mixed in the staying fluid medium may ignite.

  In view of the above-described problems of the prior art, an object of the present invention is to provide a gasification power generation system that can reliably remove dust and clean a dust collector without reducing power generation efficiency in the gasification power generation system. A first object is to provide a gasification power generation method.

  Furthermore, even when a circulating fluidized bed type gasification furnace is used as a gasification furnace, a gasification power generation system that can operate stably by reliably functioning a loop seal without reducing the calorific value of the generated gas. A second object is to provide a gasification power generation method.

  The above object can be achieved by the invention described in the claims. That is, the characteristic configuration of the gasification power generation system according to the present invention includes a gasification furnace that heats and gasifies a gasification product, and a generated gas that is disposed downstream of the gasification furnace and is generated from the gasification furnace. And a gasification power generation system capable of supplying the generated gas purified by the dust collection means to a power generation facility, wherein the dust collection means is a filtration type dust collector, and the filtration type When the dust attached to the dust collector is removed by a pulse jet, a combustible gas supply mechanism using a combustible gas for the pulse jet is provided.

  According to this configuration, since dust removal in the dust collecting means is performed by a combustible gas instead of nitrogen or the like, the calorific value of the generated gas can be obtained without diluting the generated gas generated from the gasification furnace. Therefore, it is possible to reliably remove dust from the dust collecting means without any trouble, and the power generation efficiency in the gasification power generation system is not lowered. Moreover, since the power generation equipment is generally equipped with equipment for supplying combustible gas as an auxiliary combustor, a new combustible gas supply equipment can be provided by branching and extending the combustible gas from the combustible gas supply equipment. There is no need to provide it. Therefore, since it is not necessary to provide a nitrogen production facility as in the prior art, the facility cost can be reduced and the installation space can be reduced.

  As a result, in the gasification power generation system, it is possible to provide a gasification power generation system that can reliably remove dust from the dust collector without reducing the power generation efficiency.

  The dust collection means has a high-temperature dust collection facility for purifying the product gas at a high temperature and a low-temperature dust collection facility for purifying the product gas that has undergone heat exchange and the temperature has been reduced. It is preferable that the combustible gas from the combustible gas supply mechanism is supplied to one or both of the dust collection facilities.

  According to this configuration, the functions of the high-temperature dust collection equipment and the low-temperature dust collection equipment can be maintained at a high level, and the generated gas is not diluted by nitrogen cleaning as in the prior art, and a high calorific value of the generated gas is ensured. It is possible to maintain high power generation efficiency in the downstream power generation facility.

  The gasification furnace is a circulating fluidized bed gasification furnace, and it is preferable to supply a combustible gas from the combustible gas supply mechanism as a loop seal introduction gas of the circulating fluidized bed gasification furnace.

  According to this configuration, for introducing a loop seal in a circulating fluidized bed gasifier, the combustion gas is not diluted with nitrogen as in the prior art, and a high calorific value of the combustion gas can be secured. More convenient. And even when using a circulating fluidized bed type gasification furnace as a gasification furnace, it is possible to reliably prevent a decrease in the amount of heat generated by the loop seal introduction gas and to provide a gasification power generation system that can be operated stably. .

  Further, the gasification power generation method according to the present invention is characterized in that a gasification product is heated and gasified by a gasification furnace, and is generated from the gasification furnace by dust collecting means disposed downstream of the gasification furnace. In the method of purifying the produced gas and supplying the refined produced gas to a power generation facility to generate electric power, dust removal in the dust collecting means is performed with a combustible gas.

  According to this configuration, in the gasification power generation system, it is possible to provide a gasification power generation method that can reliably remove dust from the dust collector without reducing the power generation efficiency.

  The gasification furnace is a circulating fluidized bed gasification furnace, and it is preferable to supply a combustible gas from the combustible gas supply mechanism as a loop seal introduction gas of the circulating fluidized bed gasification furnace.

  According to this configuration, even when a circulating fluidized bed gasification furnace is used as the gasification furnace, it is possible to provide a gasification power generation method that can prevent a decrease in the amount of heat generated by the loop seal introduction gas and can be stably operated. .

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart showing a schematic overall configuration of a gasification power generation system according to the present embodiment.

  This gasification power generation system includes a circulating fluidized bed gasification furnace 23 which is a kind of gasification furnace in which an organic gasification product such as biomass is introduced as fuel 21, and a dust collecting means for purifying the generated gas. The high-temperature dust collection facility 24, the tar decomposition facility 25 for decomposing / removing tar contained in the generated gas, the heat exchanger 26 for recovering heat from the generated gas, and the heat recovered to a low temperature A low-temperature dust collection facility 28 that is a dust collecting means for removing dust in the generated gas, and a purification facility 29 that removes harmful components from the generated gas, and the like, and gasification as will be described later. A combustible gas supply mechanism for supplying natural gas from the natural gas supply facility 27 is provided for introducing the loop seal of the furnace 1 or for dust removal of the high temperature dust collection facility 24 and the low temperature dust collection facility 28. The generated and purified combustion gas is sent to a power generation facility such as a downstream gas engine, gas turbine, or fuel cell.

  In the gasification furnace 23, in addition to the fuel 21, an appropriate amount of air 20, water vapor 22 and the like can be input at an appropriate timing. When the circulating fluidized bed gasifier 23 is used as the gasification furnace, as described above, the cyclone is adjacent to each other, and it is necessary to install a loop seal as a separation part between the lower part of the cyclone and the circulating fluidized bed gasification furnace. However, as the loop seal introduction gas, in this embodiment, natural gas is supplied from a natural gas supply facility 27 constituting a combustible gas supply mechanism described later. If it does in this way, it can prevent that the product gas generated by heating and decomposition | disassembly of a to-be-gasified material is diluted with nitrogen for loop seal introduction | transduction like a prior art.

  Since the generated gas is usually 800 to 900 ° C., it is supplied to the high temperature dust collecting equipment 24 equipped with a ceramic filter or the like. The dust accumulated in the ceramic filter or the like of the high-temperature dust collection facility 24 is blown off by blowing natural gas from the direction opposite to the flow direction of the generated gas by a pulse jet. ing.

  The product gas, which has been dedusted and cleaned, is further fed to a tar decomposition facility 25 equipped with a cracking catalyst such as tar to be decomposed in order to remove a small amount of tar contained in the gas. This prevents tars from adhering to various facilities and pipes in the system, thereby ensuring stable operation.

  Even at this stage, since the combustion gas has a heat of about 750 to 800 ° C., the heat recovered through heat exchange is effectively used as a heat source for various facilities.

  The product gas cooled to about 200 ° C. or less by the heat exchanger 26 is sent to a low-temperature dust collection facility 28 such as a bag filter for further purification. Although not shown in the figure, the product gas is neutralized by blowing a heavy soot or the like as necessary before the acidic components in the gas are removed before being sent to the low temperature dust collection equipment 28. In addition, harmful substances may be removed by blowing activated carbon.

  Thereafter, the combustion gas is supplied to the purification facility 29 to be purified to remove hydrogen sulfide and the like that may be contained in the gas. Thereby, the stable operation in the downstream power generation facility can be maintained.

  Next, a dust removal mechanism for the high temperature dust collection facility 24 and the low temperature dust collection facility 28 will be described. This dust removal mechanism receives the supply of combustible gas from the combustible gas supply mechanism to remove dust. That is, the piping is branched and extended from the line of the combustible gas supply facility 27 provided as the auxiliary combustor introduction facility for the power generation device disposed on the downstream side, so that the high temperature dust collection facility 24 and the low temperature dust collection facility 28 A natural gas is intermittently blown by a pulse jet method instead of the conventional nitrogen blowing by connecting to a dust removing device. In general, the product gas generated from biomass or the like does not always maintain a high calorific value, so that in order to increase power generation efficiency in the power generation facility and ensure stable operation, flammable gas such as natural gas is supported. It is added and supplied as a flame retardant so that it can be co-fired. A pipe is branched and extended from the combustible gas supply equipment 27 to introduce a loop seal in the circulating fluidized bed gasification furnace 23, or to remove dust from the high temperature dust collection equipment 24 and the low temperature dust collection equipment 28. As natural gas is supplied. Therefore, in the case of this embodiment, it is not necessary to newly install a natural gas supply facility, and it is not necessary to newly secure a space for that purpose.

  By doing so, it is not necessary to dilute the combustion gas generated from the gasification furnace as compared with the conventional blowing with nitrogen, and as a result, without reducing the power generation efficiency, it is still possible to remove dust from the dust collector. In addition to being able to reliably drop, when a circulating fluidized bed gasification furnace is used as the gasification furnace, it is possible to prevent a decrease in the amount of heat generated by the loop seal introduction gas or to prevent ignition of unburned carbon. In addition, since it is not necessary to provide a nitrogen production facility, the facility cost can be saved and the space can be reduced.

  Of course, it is preferable to spray the natural gas to both the high temperature dust collection equipment 24 and the low temperature dust collection equipment 28, but it is not always necessary to perform both of them, for example, a high temperature with a large amount of blowing gas for dust removal. You may make it carry out only with respect to the dust collection equipment 24. FIG. Even if it does in this way, the dilution to product gas can be reduced effectively and the calorific value of product gas will not be reduced.

  Below, when the gasification power generation system of the present embodiment is implemented, the heat generation amount at the power generation facility inlet side of the generated gas and the heat generation amount at the power generation facility inlet side of the generated gas in the prior art in which nitrogen is blown are performed, respectively. Example 1 and Comparative Example 1 are shown in comparison with Table 1.

ガス化炉としては、処理量１００ｔ／日の循環流動層式ガス化炉を用い、実施例１に関しては、窒素の代わりに天然ガス（都市ガス１３Ａ）を用いて高温集塵設備および低温集塵設備に対して、パルスジェット方式で所定量の天然ガス吹込みを行いダスト払い落としを行った。比較例１では、高温集塵設備および低温集塵設備に対して、天然ガスと同量（比重換算）の窒素を吹込むことによりダスト払い落しを行った。

As the gasification furnace, a circulating fluidized bed type gasification furnace with a throughput of 100 t / day was used. Regarding Example 1, natural gas (city gas 13A) was used instead of nitrogen, and high-temperature dust collection equipment and low-temperature dust collection were used. A predetermined amount of natural gas was blown into the facility using a pulse jet method to remove dust. In Comparative Example 1, dust was removed by blowing nitrogen in the same amount (in terms of specific gravity) as natural gas into the high temperature dust collection facility and the low temperature dust collection facility.

  From the results in Table 1, the calorific value (removing moisture) of the combustion gas in Example 1 is about twice that of the comparative example, and it has a high calorific value and is input to the power generation equipment. Therefore, high power generation efficiency can be secured, and the energy efficiency of the entire system can be increased.

[Another embodiment]
(1) In the above embodiment, an example in which a circulating fluidized bed type gasification furnace is used as the gasification furnace is shown, but the gasification furnace to which the present invention can be applied is not limited to this, Various types such as various fluidized bed gasifiers such as a bubbling fluidized bed gasifier, a fixed bed gasifier, and a kiln gasifier can be used.
(2) In the above embodiment, an example in which natural gas is supplied and sprayed from the combustible gas supply equipment 27 as the combustible gas supply mechanism has been shown, but propane gas, dimethyl ether, or the like may be used instead of natural gas. May be any flammable gas.

The flowchart which shows the schematic whole structure of the gasification electric power generation system which concerns on one Embodiment of this invention. Schematic overall configuration diagram of a conventional gasification power generation system

Explanation of symbols

23 Gasifier 24, 28 Dust collection means 27 Combustible gas supply mechanism

Claims (5)

A gasification furnace that heats and gasifies the material to be gasified, a dust collecting means that is disposed downstream of the gasification furnace and purifies a generated gas generated from the gasification furnace, and is purified by the dust collecting means In the gasification power generation system in which the generated gas can be supplied to the power generation facility, the dust collecting means is a filtration type dust collector, and dust attached to the filtration type dust collector is removed by a pulse jet. The gasification power generation system is characterized in that a combustible gas supply mechanism using a combustible gas for the pulse jet is provided. The dust collection means has a high-temperature dust collection facility for purifying the product gas at a high temperature and a low-temperature dust collection facility for purifying the product gas that has undergone heat exchange and the temperature has been reduced. The gasification power generation system according to claim 1, wherein the combustible gas from the combustible gas supply mechanism is supplied to one or both of the dust collection facilities. The gasification furnace is a circulating fluidized bed type gasification furnace, and a combustible gas from the combustible gas supply mechanism is supplied as a loop seal gas for the circulating fluidized bed type gasification furnace. The gasification power generation system described. A gasification object is heated and gasified by a gasification furnace, a generated gas generated from the gasification furnace is purified by a dust collecting means disposed downstream of the gasification furnace, and the purified combustion gas is generated by power generation In the gasification power generation method for supplying power to equipment and generating power, the dust collection means performs dust removal by a combustible gas. The said gasification furnace is a circulating fluidized bed type gasification furnace, The combustible gas from the said combustible gas supply mechanism is supplied as a loop seal introduction gas of this circulating fluidized bed type gasification furnace. Gasification power generation method.

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