JP4528145B2 - Integrated gasifier and method of operation thereof - Google Patents

Description

  The present invention relates to a gasification furnace for pyrolyzing and gasifying organic waste such as waste plastic and wood, and in particular, a gasification chamber for pyrolyzing and gasifying organic waste and an organic waste. The present invention relates to an integrated gasification furnace having a combustion chamber for burning char and tar generated by thermal decomposition and accompanying a fluid medium in one fluidized bed furnace, and an operation method thereof.

  As a method for treating organic waste such as plastic and wood, a method is known in which organic waste is pyrolyzed and gasified in a gasification furnace to extract combustible gas. As this gasification furnace, Patent Document 1 discloses a gasification chamber in which fuel such as organic waste is pyrolyzed and gasified, and char and tar generated by pyrolysis of organic waste and accompanying a fluid medium. An integrated gasifier having a combustion chamber and a combustion chamber in one fluidized bed furnace is disclosed.

In such an integrated gasification furnace, as the fluidizing gas in the gasification chamber, in addition to water vapor contributing to the gasification reaction (C + H ₂ O → CO + H ₂ ), CO ₂ , N contributing to fluidization state maintenance _{2. A} gas that does not contain oxygen molecules, such as a self-generated gas, is required.

However, when CO ₂ or N ₂ is used as the fluidizing gas, there is a problem that CO ₂ and N ₂ are expensive and a gas generating device is necessary, and in addition, they are generated in the gasification chamber. There is a problem that the combustible gas is diluted and the gas calorie is reduced. In addition, when the self-generated gas, that is, the gas generated in the gasification chamber is circulated and used as the fluidizing gas, there is a problem that a gas circulation device such as a blower is required. For this reason, a fluidized gas that can be supplied at low cost is required.

  On the other hand, blast furnace gas and converter gas generated at steelworks contain flammable gases such as CO, but CO has low calories, and blast furnace gas burns with low calories because of its low CO content. Since it has poor properties and does not emit a luminous flame, it cannot be used alone as a fuel gas for a heating furnace. For this reason, when used as a fuel gas for a heating furnace, a high calorie gas such as coke oven gas is mixed and used after calorie increase.

However, there is a problem that the amount of coke oven gas is limited and the cost is high, and there is a problem that when city gas or the like is purchased and used, it is expensive and further expensive. Therefore, other effective utilization methods of blast furnace gas and converter gas are required.
JP-A-11-181450

  The problem to be solved by the present invention is to enable the fluidization gas in the gasification chamber to be supplied at low cost in the integrated gasification furnace and to effectively use the blast furnace gas and the converter gas.

In order to solve the above-mentioned problems, the present invention provides a gasification chamber in which organic waste is pyrolyzed and gasified in one fluidized bed furnace, and a fluidized medium produced by pyrolyzing organic waste. In an integrated gasification furnace comprising a combustion chamber for combusting associated materials to circulate between the gasification chamber and the combustion chamber, steam and blast furnace from the blast furnace are used as the fluidization gas in the gasification chamber A means for supplying gas and / or converter gas from the converter is provided , and the change in the amount of fluidized gas with respect to the change in the amount of organic waste treated coincides with the change in the amount of water vapor as the gasifying agent. Therefore, the supply amount of water vapor is adjusted in proportion to the treatment amount of organic waste so that the supply amount of water vapor becomes a necessary amount for the gasification reaction of organic waste. / Or converter gas, or coke oven gas mixed with this As the supply amount of the scan is the shortage of the amount of gas required for fluidization and circulation of the fluidized medium, characterized in that a means for adjusting the respective supply amounts.

The present invention also provides a operation method of the integrated gasification furnace, as a fluidizing gas in the gasification chamber, and steam is supplied to the converter gas from blast furnace gas and / or converter from blast furnace, this time Since the change in the amount of fluidized gas with respect to the change in the amount of organic waste treated does not coincide with the change in the amount of water vapor as a gasifying agent, the amount of water vapor supplied is excessive or insufficient for the gasification reaction of organic waste The supply amount of water vapor is adjusted in proportion to the amount of organic waste treated so that it becomes the required amount, and the supply amount of blast furnace gas and / or converter gas, or gas mixed with coke oven gas. Is characterized in that each supply amount is adjusted so that the amount of gas necessary for fluidization and circulation of the fluidized medium becomes a shortage .

  In the present invention, a gas obtained by mixing a coke oven gas from a coke oven with a blast furnace gas and / or a converter gas can be used as the fluidizing gas in the gasification chamber.

  Furthermore, at least a part of the fluidized gas supplied to the gasification chamber can be preheated by indirect heat exchange using the combustion heat or waste heat of the combustion chamber.

According to the present invention, since blast furnace gas and converter gas are used as the fluidizing gas in the gasification chamber, expensive gas such as CO ₂ and N ₂ and a gas generator are not necessary, and self-generated gas is used. A circulating gas circulation device is also unnecessary, and fluidized gas can be supplied at low cost.

Moreover, compared with the case of using the CO _2, N ₂ as a fluidizing gas, converter gas, by caloric content, with the blast furnace gas, it is possible to increase the calories of the gas obtained from the gasification chamber. In other words, the calorie of the converter gas and blast furnace gas can be increased, leading to its effective use.

  Embodiments of the present invention will be described below based on examples shown in the drawings.

  FIG. 1 is a schematic configuration diagram showing an integrated gasification furnace of the present invention. The integrated gasification furnace includes a gasification chamber 1 and a combustion chamber 2 in one fluidized bed furnace. The gasification chamber 1 and the combustion chamber 2 are separated by a partition wall 3.

  Organic waste such as waste plastic is put into the gasification chamber 1 and the input organic waste is heated by contact heat transfer with the fluid medium in the gasification chamber 1 to be thermally decomposed and gasified. . The generated pyrolysis gas (combustible gas) is discharged from the gasification chamber 1 and collected. On the other hand, part of the char and tar generated by pyrolysis flows into the combustion chamber 2 from the opening (not shown) of the partition wall 3 along with the fluid medium (sand in the embodiment) together with the fluid medium. Burns in 2. The fluid medium in the combustion chamber 2 heated by the combustion of the char or tar flows into the gasification chamber 2 from an opening (not shown) of the partition wall 3. In this way, the fluid medium circulates between the gasification chamber 1 and the combustion chamber 2 and is heated by combustion of char and tar in the combustion chamber 2 during the circulation.

In such an integrated gasifier, in addition to water vapor that contributes to the gasification reaction (C + H ₂ O → CO + H ₂ ), a gas that does not contain oxygen molecules is supplemented as the fluidizing gas in the gasification chamber 1. It is necessary to maintain a fluidized state. FIG. 2 shows the relationship between the amount of fluidized gas required and the amount of organic waste processed. As shown in the figure, the fluidizing gas requires an amount of water vapor that is proportional to the amount of organic waste processed, and the amount of fluidized gas (total) and the amount of water vapor necessary to maintain the fluidized state. Is the amount of gas that needs to be supplemented with a gas that does not contain oxygen molecules. In the present invention, this is supplemented with blast furnace gas, converter gas, or both.

  In order to maintain a fluidized state in the gasification chamber 1, it is necessary to continue supplying a certain amount or more of fluidizing gas. When fluidization is performed using low calorie gas mainly composed of blast furnace gas, blast furnace gas is used. However, the calorie of the obtained gas is slightly diluted, and there is an upper limit to the calorie of the obtained gas. Therefore, in the case of further increasing the calorie of the obtained gas, as shown in FIG. 1, the coke oven gas from the coke oven gas pipe 14 is mixed with the blast furnace gas or the converter gas, or both, and the low calorie gas is mixed. It is possible to improve the calorie by reducing the ratio.

  Here, the reason why it is necessary to adjust the gas compensation amount for maintaining fluidization will be described. First, as shown in Fig. 3, the amount of operation heat required for pyrolysis and gasification in a gasification furnace is composed of three types of heat dissipation, pyrolysis heat, and gas sensible heat. Is proportional to the amount of treatment, so as the amount of treatment increases, the gasifier operating heat increases as a linear function. The gasifier operating heat quantity is supplied as a product of the temperature difference between the fluidized medium in the gasification chamber and the combustion chamber and the circulation rate. Under conditions where the temperature difference is constant in a steady state, as shown in FIG. Is proportional to the circulation rate of the fluid medium. Further, as shown in FIG. 5, the amount of fluidizing gas necessary for maintaining the fluidized state has a part depending on the circulating amount of the fluidized medium and a part not dependent on the circulating amount of the fluidized medium, the latter being the hearth area. However, the former increases according to the circulation amount of the fluid medium. Thus, when the processing amount of organic waste increases, the amount of fluidized gas for that purpose increases from the necessity of increasing the circulating amount of the fluidized medium. The change in the amount of fluidized gas does not coincide with the change in the amount of water vapor as the gasifying agent shown in FIG. 2, and the system design is such that the amount of fluidized gas is larger than the amount of water vapor. There is a need to adjust the gas supplement for maintenance. Further, the gas to be filled in the gasification chamber needs to be a gas not containing oxygen molecules so that a combustion reaction does not occur.

  In the present invention, the amount of water vapor necessary for the gasification reaction is obtained as a breakdown of the fluidized gas in the gasification chamber 1 according to the amount of organic waste treated, and as described above, the amount of fluidized gas and the amount of water vapor required are determined. The difference, that is, the shortage is compensated with blast furnace gas and / or converter gas, or a gas mixed with coke oven gas (hereinafter referred to as “blast furnace gas”). The flow rate calculation of the steam and blast furnace gas can be performed by the control device 4, and the flow rate control valve is provided in each of the steam pipe 5, the blast furnace gas (converter gas) pipe 6 and the coke oven gas pipe 14. This can be done by adjusting the opening degree of 7, 8, 15 with the control device 4.

  In actual operation, the amount of water vapor is set in proportion to the amount of treatment measured by the treatment amount measuring device 9, and the composition of the generated gas by the gas analyzer 10, the temperature of the gasification chamber by the thermometer 11 (Tgs, Tgg), etc. It can be corrected by the measured value. The amount of fluidized gas is set according to the hearth area and throughput, and the temperature information of the gasification chamber by the thermometer 11 (Tgs, Tgg), the temperature information of the combustion chamber by the thermometer 11 (Tcs, Tcg), and the fluidization state It can be corrected by measurement information. The fluidized state can be measured by the relationship between the fluidized gas flow rate and the fluidized medium layer differential pressure measured by the differential pressure gauge 12 and the observation of the ITV 13.

  As the fluidizing gas in the combustion chamber 2, air is introduced in the embodiment in order to combust char and tar accompanying the fluid medium, and the combustion exhaust gas is a separate system from the pyrolysis gas from the gasification chamber 1. Discharged.

  FIG. 6 is a schematic configuration diagram showing another embodiment of the integrated gasification furnace of the present invention. 6, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In the embodiment shown in FIG. 6, steam and blast furnace gas supplied as fluidized gas in the gasification chamber 1 are preheated by indirect heat exchange using combustion heat or waste heat in the combustion chamber 2. The steam is preheated using the combustion heat in the combustion chamber 2 by a steam preheating device 16 provided in the combustion chamber 2. The blast furnace gas and the like are preheated by a first gas preheating device 17 that uses water vapor obtained from the waste heat of the combustion chamber 2 and a second gas preheating device 18 that directly uses the waste heat of the combustion chamber 2.

  In this embodiment, similarly to the embodiment of FIG. 1, the flow rate control valves 7 provided for the steam pipe 5, the blast furnace gas (converter gas) pipe 6 and the coke oven gas pipe 14 are respectively controlled for the flow rate of steam and blast furnace gas. , 8 and 15 are adjusted by the control device 4.

It is a schematic block diagram which shows the integrated gasifier of this invention. The relationship between the amount of fluidized gas required in the integrated gasifier and the amount of organic waste treated is shown. The relationship between the amount of organic waste treated and the heat of gasifier operation is shown. The relationship between gasifier operating heat and fluidized medium circulation is shown. The relationship between the fluid medium circulation amount and the fluidized gas amount is shown. It is a schematic block diagram which shows another Example of the integrated gasifier of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gasification chamber 2 Combustion chamber 3 Partition wall 4 Control apparatus 5 Steam pipe 6 Blast furnace gas (converter gas) pipe 7, 8 Flow control valve 9 Treating amount measuring apparatus 10 Gas analyzer 11 Thermometer 12 Differential pressure gauge 13 ITV
14 Coke Oven Gas Pipe 15 Flow Control Valve 16 Steam Preheater 17 First Gas Preheater 18 Second Gas Preheater

Claims (2)

In one fluidized bed furnace, there are provided a gasification chamber for pyrolyzing organic waste to gasify, and a combustion chamber for burning accompanying substances generated by pyrolysis of organic waste and accompanying the fluidized medium. In an integrated gasifier that circulates a fluid medium between a gasification chamber and a combustion chamber,
A means for supplying water vapor and blast furnace gas from a blast furnace and / or converter gas from a converter as a fluidizing gas in a gasification chamber is provided .
Furthermore, the change in the amount of fluidized gas with respect to the change in the amount of organic waste treated does not coincide with the change in the amount of water vapor as a gasifying agent, so that the amount of steam supplied exceeds the gasification reaction of organic waste. The supply amount of water vapor is adjusted in proportion to the treatment amount of organic waste so that it becomes the required amount without shortage, and the supply of blast furnace gas and / or converter gas, or gas mixed with coke oven gas. An integrated gasification furnace characterized in that means for adjusting each supply amount is provided so that the amount becomes a shortage of a gas amount necessary for fluidization and circulation of a fluid medium . In one fluidized bed furnace, there are provided a gasification chamber for pyrolyzing organic waste to gasify, and a combustion chamber for burning accompanying substances generated by pyrolysis of organic waste and accompanying the fluidized medium. In the operation method of the integrated gasification furnace in which the fluidized medium is circulated between the gasification chamber and the combustion chamber,
Supplying steam, blast furnace gas from the blast furnace and / or converter gas from the converter as fluidizing gas in the gasification chamber ,
At this time, the change in the amount of fluidized gas with respect to the change in the amount of organic waste treated does not coincide with the change in the amount of water vapor as the gasifying agent. The supply amount of water vapor is adjusted in proportion to the amount of organic waste treated so that it becomes the required amount without excess or deficiency, and the blast furnace gas and / or converter gas, or a mixture of this with coke oven gas A method for operating an integrated gasification furnace, characterized in that each supply amount is adjusted so that the supply amount is a shortage of a gas amount necessary for fluidization and circulation of a fluid medium .

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