JP2009067979A - Gasification reactor for forming combustible gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasification reactor for obtaining a combustible gas utilizing organic resources (biomass, refuse, sewage sludge, etc.), coal, etc. as a hydrocarbon-based solid fuel, wherein, an amount of a combustible gas obtainable from a combustion furnace is increased by accelerating gasification of high char-content fuel at low temperature, thus the combustible gas is obtained in a high efficiency. <P>SOLUTION: The reactor for gasifying hydrocarbon-based solid fuels is equipped with, each independently, an alkali-adsorbing furnace, wherein adsorption of alkali and/or alkali earth metals evaporated in a course of thermal cracking of hydrocarbon-based solid fuels such as organic resources, coal, etc. are performed actively, a gasification furnace for gasifying char introduced from the alkali-adsorbing furnace, and a combustion furnace for forming a combustion gas by burning a residual char introduced from the gasification furnace, wherein, absorption efficiency of alkali and/or alkali earth metals by char is made higher by making the alkali-adsorbing furnace a moving bed-type. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gasification reactor for using organic resources such as biomass, garbage, sewage sludge, and coal as a hydrocarbon-based solid fuel and taking it out as a flammable gas, particularly in a gasifier. The present invention relates to a high-efficiency gasification reactor for promoting the gasification of char and taking out combustible gas with high efficiency.

Conventionally, technologies have been developed to make effective use of organic resources by using organic resources such as biomass, garbage, and sewage sludge as hydrocarbon-based solid fuel, and using the generated gas as a combustible gas and heat source. ing.
In order to take out the generated gas as a combustible gas, there is a problem that tar contained in the generated gas precipitates or burns when the char comes into contact with oxygen. Generally, biomass, garbage, sewage sludge, etc. Organic hydrocarbons, coal, etc. are used as hydrocarbon-based solid fuel, which is gasified into a combustible gas in a gasification furnace, and then the unburned residue is led to the combustion furnace to oxidize oxygen, air, etc. The method of using as a combustion gas is adopted.

  In the method and apparatus for using conventional organic resources as hydrocarbon solid fuel and taking out as combustible gas (see Patent Documents 1 and 2 below), evaporated alkali may be adsorbed to char, but this is possible. Because of its extremely low efficiency, the ratio of char introduced into the combustion furnace is high, and the amount of product gas that can be taken out by the gasifier is small, that is, the gasification efficiency is low. The current situation is that the problem of promoting the development has not been solved. There is also a demand for taking out the product gas with higher efficiency even for high volatile content fuel.

As one of the techniques for solving these problems, the present inventors have separated a conventional combustion furnace and a gasification furnace, and in addition to a method of separately taking out the combustion gas and the gasification gas, the gasification furnace is further provided. A method has been proposed in which the pyrolysis gas and the gasification gas are separately extracted separately from the alkali absorption furnace and the char gasification furnace (see Patent Document 3 below).
According to the gasification method and the gasification reactor of the present proposal, it is possible to eliminate the influence of inhibition by pyrolysis gas and tar in char gasification. Further, in an alkali absorption furnace having a bubble fluidized bed, alkali is evaporated from a solid fuel having a high alkali content and adsorbed on the solid fuel having a high char content, and the alkali is used as a gasification catalyst for char. Thus, char gasification is promoted in the char gasification furnace.
JP 2005-68297 A JP 2005-68373 A Japanese Patent Application No. 2007-123373

  As a result of further studies by the present inventors, when the alkali absorption furnace is a bubble fluidized bed as in the proposed reactor, the residence time of gas and particles can be increased as compared with the high-speed fluidized bed. However, it became clear that the problem of contact between alkali and char remained. Moreover, although the alkali absorption furnace is made into a two-stage furnace, the alkali is evaporated in the lower stage, and the alkali is adsorbed to the char in the upper stage, it can be adsorbed with higher efficiency than the one-stage bubble fluidized bed, but the reaction furnace is large. I also found that there was a problem.

  The present invention has been made in view of the circumstances as described above, and its purpose is to use organic resources such as biomass, waste, sewage sludge, and coal as a hydrocarbon-based solid fuel, as a combustible gas. To provide a gasification reactor capable of taking out combustible gas with high efficiency by increasing the amount of product gas that can be taken out in a gasification furnace by promoting gasification of a solid fuel containing a large amount of char at a low temperature. is there. Furthermore, another object of the present invention is to provide a gasification furnace capable of producing a combustible gas with a more efficient and compact structure.

  In the process of studying to solve the above-mentioned problems, the present inventors have made the alkali absorption furnace a moving bed, thereby allowing alkali and / or evaporated from a solid fuel having a high alkali and / or alkaline earth metal content. Alternatively, in the process of adsorbing alkaline earth metal to a solid fuel having a high char content, it was found that alkali and / or alkaline earth metal can be adsorbed to char with higher efficiency, leading to the completion of the present invention. It is a thing.

That is, according to the present invention, the following inventions are provided.
(1) An alkali absorption furnace that actively adsorbs alkali and / or alkaline earth metal evaporated during pyrolysis of hydrocarbon solid fuel such as organic resources and coal, introduced from the alkali absorption furnace A gasification furnace for gasifying the char and a combustion furnace for generating combustion gas by burning the residual char introduced from the gasification furnace are provided independently, and the respective furnaces are connected in this order by communication paths. A hydrocarbon-based solid fuel gasification reactor comprising: an alkali and / or alkaline earth evaporated from a solid fuel having a high alkali and / or alkaline earth metal content by using the alkali absorption furnace as a moving bed. In the process of adsorbing an alkali metal to a solid fuel with a high char content, the alkali and / or alkaline earth metal is adsorbed to the char with higher efficiency. Gasification reactor of a hydrocarbon-based solid fuel, characterized.
(2) The alkali absorption furnace as the moving bed is provided with means for supplying a solid fuel with a high char content and a means for supplying a solid fuel with a high alkali and / or alkaline earth metal content, and the evaporated alkali The gasification reactor for hydrocarbon-based solid fuel according to (1), wherein an alkaline earth metal is adsorbed onto the char with higher efficiency.
(3) The volatile pyrolysis gas generated by pyrolysis in the alkali absorption furnace, the gasification gas generated by char gasification in the gasification furnace, and the combustion gas generated in the combustion furnace are each independently provided. The hydrocarbon solid fuel gasification reactor according to (1) or (2), characterized in that a means for taking out is provided.

  According to the present invention, by completely separating the alkali absorption furnace and the gasification furnace, it is possible to eliminate the influence of the inhibition of char gasification by the pyrolysis gas and tar. Moreover, according to this invention, the pyrolysis gas produced | generated in an alkali absorption furnace and the gasification gas produced | generated in a gasification furnace can be taken out separately. Furthermore, in the present invention, alkali and / or alkaline earth metal evaporated from a solid fuel having a high alkali and / or alkaline earth metal content such as biomass, garbage, and sewage sludge is contained in a char content such as coal. Therefore, it is possible to effectively utilize the evaporated alkali and / or alkaline earth metal as a char gasification catalyst.

Embodiments of the present invention will be described with reference to the drawings.
(First form)
FIG. 1 is a schematic diagram showing a first embodiment of a reaction furnace used in the present invention, in which an alkali absorption furnace, a gasification furnace, and a combustion furnace are provided independently, and each furnace is connected by a communication passage. They are connected in order.
In the reactor shown in FIG. 1, biomass, garbage, organic resources such as sewage sludge, and hydrocarbon-based solid fuel such as coal are supplied to an alkali absorption furnace and a part of the generated combustion gas is recirculated. Introduced CO ₂ gas, an inert gas such as N ₂ or Ar, water vapor or the like is introduced and thermally decomposed. In order to adsorb the alkali and / or alkaline earth metal evaporated during the thermal decomposition of the fuel in the alkali absorption furnace to the char with high efficiency, the moving bed is used. The pyrolysis gas and particles generated by the cyclone are separated, and the char and the fluidized medium are introduced into the next gasifier.
A means for taking out the generated pyrolysis gas is provided at the upper part of the alkali absorption furnace. The extracted pyrolysis gas is a kind of combustible gas and is used for power generation by a fuel cell or a gas engine, liquid fuel, etc., but since it contains tar, the use of porous particles as a fluid medium, It is necessary to decompose and remove tar by a reforming furnace or a tar absorption tower using activated carbon after the furnace.

The gasification furnace is a fluidized bed, and the unburned char introduced from the alkali absorption furnace is gasified by a gasification reaction with a gasifying agent introduced from the lower part. As the gasifying agent, steam, oxygen or air is used as partial oxidation combustion.
The gasification gas generated in the gasification furnace is taken out from the upper part of the gasification furnace, while the residual char and the fluidized medium are introduced into the next combustion furnace.
The extracted gasified gas is a combustible gas, and is used for power generation by a fuel cell or a gas engine, liquid fuel, or the like.

The combustion furnace is a fluidized bed, and ensures a residence time during which the residual char can be completely combusted. In the combustion furnace, the introduced residual char is burned together with oxygen or air introduced from the lower part of the combustion furnace, and the combustion gas is taken out by a cyclone. On the other hand, the reheated fluid medium is returned again to the alkali absorption furnace.
The extracted combustion gas is used as a heat source, and as described above, a part of the combustion gas can be recycled to the alkali absorption furnace. Moreover, it can utilize also as preheating of the air, steam, etc. which are introduce | transduced into the said gasification furnace or a combustion furnace.

  2 and 3 are the reactors shown in FIG. 1 in which the structure of the communication path between the alkali absorption furnace and the gasification furnace is changed, and the reactors shown in FIGS. , The flow of the solid fuel and the fluid medium are the same, and the alkali absorption furnace → communication path → gasification furnace → communication path → combustion furnace → cyclone (not shown) → downcommer (not shown) → It becomes an alkali absorption furnace.

(Second form)
A second form of the reactor used in the present invention is a means for supplying a solid fuel having a high char content such as coal to the alkali absorption furnace as the moving bed, and an alkali such as biomass, garbage, and sewage sludge. And / or means for supplying a solid fuel having a high alkaline earth metal content.
FIG. 4 shows an example of the second embodiment of the present invention. In the reactor shown in FIG. 1, solid fuel (a high content of char such as coal is higher than the upper part of the alkali absorption furnace). Contained char fuel) from the side is supplied with solid fuels with high alkali and / or alkaline earth metal content such as biomass, garbage, and sewage sludge (highly contained alkaline fuel), and these hydrocarbon solids Thermally decompose the fuel.
In the reactor shown in FIG. 4, the pyrolysis gas generated from the solid fuel having a high alkali and / or alkaline earth metal content and the evaporated alkali and / or alkaline earth metal have a high content of the upper char. It becomes possible to adsorb to the solid fuel with higher efficiency.

FIG. 4 shows an example in which means for supplying a solid fuel having a high char content and means for supplying a solid fuel having a high alkali and / or alkaline earth metal content are provided at the upper and side portions of an alkaline absorption furnace, respectively. However, in the present invention, since the alkali absorption furnace is a moving bed, it is sufficient if both means are provided, may be provided in different places, or may be provided in the same place, Those places are not limited at all.
For example, FIG. 5 shows that the reactor shown in FIG. 1 is supplied with both high-content char fuel such as coal and high-content alkali fuel such as biomass, garbage, and sewage sludge from the upper part of the alkali absorption furnace. It is to be pyrolyzed.
Also in FIGS. 2 and 3, the same effect can be obtained if the fuel supply method is the same as in the second embodiment of FIGS.

  According to the present invention, by completely separating the alkali absorption furnace and the gasification furnace, it is possible to eliminate the influence of the gasification of char due to pyrolysis gas and tar, and it is possible to gasify with high efficiency. Therefore, effective use for unused hydrocarbon resources such as biomass, garbage, and sewage sludge is expected. Further, according to the present invention, by using the alkali absorption furnace as the moving bed, it is easy to adsorb the alkali and / or alkaline earth metal evaporated by pyrolysis to the char with high efficiency. Therefore, hybrid gasification of solid fuel (co-gasification), in particular, hybrid gasification of organic waste fuel such as biomass, waste, sewage sludge, etc. with coal becomes possible. Effective use is expected. Furthermore, the combustible gas obtained by the present invention, that is, the pyrolysis gas obtained from the alkali absorption furnace and the gasification gas obtained from the gasification furnace are effective for power generation by a fuel cell or gas engine, liquid fuel, etc., respectively. Used.

Schematic diagram showing the first embodiment of the reactor of the present invention FIG. 1 is a schematic diagram showing an example in which the communication path between an alkali absorption furnace and a gasification furnace is changed in the reaction furnace of FIG. FIG. 1 is a schematic diagram showing another example in which the communication path between the alkali absorption furnace and the gasification furnace is changed in the reaction furnace of FIG. Schematic diagram showing an example of the second embodiment of the reactor of the present invention Schematic diagram showing another example of the second embodiment of the reactor of the present invention

Claims (3)

  An alkali absorption furnace that actively adsorbs alkali and / or alkaline earth metal evaporated during pyrolysis of hydrocarbon-based solid fuels such as organic resources and coal, and char introduced from the alkali absorption furnace as a gas A hydrocarbon comprising: a gasification furnace to be converted; and a combustion furnace for independently burning the residual char introduced from the gasification furnace to generate combustion gas; A solidification fuel gasification reactor, wherein the alkali absorption furnace is used as a moving bed, so that alkali and / or alkaline earth metal evaporated from a solid fuel having a high alkali and / or alkaline earth metal content can be obtained. In the process of adsorbing to a solid fuel with a high char content, the char is adsorbed with alkali and / or alkaline earth metal with higher efficiency. Gasification reactor of a hydrocarbon-based solid fuel.   A means for supplying a solid fuel with a high char content and a means for supplying a solid fuel with a high alkali and / or alkaline earth metal content are provided in the alkali absorption furnace as the moving bed, and the evaporated alkali and / or 2. The hydrocarbon solid fuel gasification reactor according to claim 1, wherein the alkaline earth metal is adsorbed onto the char with higher efficiency.   Means for independently taking out volatile pyrolysis gas generated by pyrolysis in the alkali absorption furnace, gasification gas generated by char gasification in the gasification furnace, and combustion gas generated in the combustion furnace The gasification reaction furnace for hydrocarbon-based solid fuel according to claim 1 or 2, wherein

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