JPH083102B2 - Coal gasifier - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coal gasifier for gasifying coal to convert it into gas fuel.

[Conventional technology]

A conventional coal gasifier will be described with reference to FIG.
In FIG. 3, the supplied coal 1 is crushed by the crusher 2 into the crushed coal 3. The crushed coal 3 is sent to the distributor 4 and distributed. The crushed coals 5 and 6 after distribution are each a coal feeder.
Sent to 7,8. The crushed coal 5,6 is supplied by the coal feeder 7,8.
Pulverized coal 9 to lower reaction chamber 11 Pulverized coal 10 to upper reaction chamber 12
Sent to.

In the lower reaction chamber 11 and the upper reaction chamber 12, a reaction for converting coal into gas is caused. The reaction to convert coal to gas is
It is classified into the following processes.

At 400 ° C. or higher, coal causes a so-called devolatilization reaction in which a part of the coal is converted into hydrogen, carbon monoxide, carbon dioxide, steam, methane, ethane, ethylene and the like by thermal decomposition. The coal after the devolatilization reaction becomes a solid called char, which is mainly composed of carbon and ash. The carbon in the char reacts with water vapor or carbon dioxide gas to be converted into hydrogen and carbon monoxide as represented by the following chemical formulas 1 and 2.

C + H ₂ O = CO + H ₂ ...... First formula C + CO ₂ = 2CO ...... Second formula Since the above two reactions occur simultaneously in the reaction chamber at 850 ° C to 2000 ° C, the two reactions are collectively referred to as gasification reaction. Called.

Since the gasification reaction is an endothermic reaction, the temperature inside the reaction chamber is 850 ℃.
In order to maintain the temperature at ˜2000 ° C., carbon in the char, coal and combustible gas in the generated gas are reacted with oxygen to cause a so-called combustion reaction.

In the lower reaction chamber 12, together with the pulverized coal 9, air or oxygen-enriched oxidizing gas which is pure oxygen.
13 and a recovery char 14 are supplied. In the lower reaction chamber 11, the pulverized coal 9 and the recovered char are suspended while floating in the air flow.
14 performs a devolatilization reaction, a gasification reaction, and a combustion reaction with the oxidizing gas 13 supplied to the lower reaction chamber 11 and converts it into hydrogen, carbon monoxide, carbon dioxide gas, steam, methane, and the like. Lower reaction chamber 11
The temperature inside is kept above the melting temperature of the ash. The ash melted in the lower reaction chamber 11 is discharged as slag 15. The gas generated in the lower reaction chamber 11 is sent to the reaction chamber 12 as the lower generated gas 16.

In the upper reaction chamber 12, the pulverized coal 10 supplied to the upper reaction chamber 12 undergoes a devolatilization reaction, a gasification reaction and a combustion reaction with the lower generation gas 16, an oxidizing gas 17, hydrogen, carbon monoxide, carbon dioxide gas, Convert to steam and methane. The unreacted pulverized coal of the reaction is sent to the char recovery device 19 as char together with the upper stage generated gas 18 generated by the reaction.

In the char recovery device 19, the char is separated from the upper-stage generated gas 18 and sent to the char feeder 21 as the recovered char 20. The upper-stage generated gas 22 after the char separation is sent to a subsequent device (not shown) as a crude purified gas. Recovery char
20 is supplied to the lower reaction chamber 11 by the char feeder 21.

[Problems to be solved by the invention]

In the conventional coal gasifier described above, when the reaction rate of the gasification reaction of carbon in the char in the upper reaction chamber is slow, the heat absorption is reduced and the temperature of the upper gas generated rises, and the ash content in the char in the upper gas is reduced. There is a problem that char flows to the char recovery unit as it melts, causing char to attach to the char recovery unit and causing blockage problems, or the char in the upper stage generated gas increases, resulting in insufficient processing capacity of the char feeder. was there.

It is an object of the present invention to provide a coal gasifier capable of increasing the gasification reaction rate in the reaction chamber and eliminating the blockage of the char recovery device and the insufficient processing capacity of the char feeder. .

[Means for solving problems]

In the present invention, a coal gasification reaction chamber is composed of a lower reaction chamber and an upper reaction chamber, and the lower reaction chamber is supplied with coal and char recovered from the gas generated in the upper reaction chamber and a gasifying agent. Coal and char are gasified and ash in the coal is melted and discharged as slag, while the upper reaction chamber is supplied with upper coal and gasification agent into which the gas and char generated in the lower reaction chamber are introduced. In a coal gasifier for gasifying coal and char to gasify the char by separating and collecting char from the upper reaction chamber generated gas that has been gasified and circulated in the lower reaction chamber, a coal crusher, A classifier that is connected to the crusher and classifies the coal after crushing into a plurality of groups having different particle sizes, and pulverized coal is connected to the classifier according to the particle size of pulverized coal. Reactor And a supply means for coal to be supplied to the plurality of stages, is to propose a coal gasifier, characterized in that it includes.

[Work]

The gasification reaction rate of carbon in char is inversely proportional to the particle size of char at the same temperature and the same gas composition conditions,
The smaller the particle size, the faster. When the pulverized coal is supplied to the upper reaction chamber, the conversion amount of carbon in the char in the upper reaction chamber to the gas can be increased as compared with the case where conventional pulverized coal is supplied to the upper reaction chamber. .

On the other hand, the lower reaction chamber is mainly composed of combustion reaction. The combustion reaction has a faster reaction speed than the gasification reaction, and since the lower reaction chamber is sufficiently high in temperature, the gasification reaction speed is also sufficiently high.Therefore, when supplying coarse coal to the lower reaction chamber and in the lower reaction chamber There is no significant difference in the amount of carbon in char converted to gas compared with the conventional case where pulverized coal is supplied.

Pulverized coal is fed to the upper reaction chamber and coarse coal is fed to the lower reaction chamber according to the particle size, after being fed to a classifier after crushing the supplied coal into a classifier and classified into a plurality of groups having different particle sizes. To supply each in multiple stages. In this way, the rate of gasification reaction in the upper reaction chamber is increased, so the amount of char is reduced, and since the gasification reaction is an endothermic reaction, the rise in the temperature of the gas generated in the upper reaction chamber is suppressed and It is possible to prevent the ash content of the ash from melting and adhering to the char recovery device to be blocked.

〔Example〕

A first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, the same reference numerals as those in FIG. 3 denote the same objects or portions having the same functions as those shown in FIG. 3, and 23 is connected to the crusher 2 and crushed by the crusher 2. A classifier for classifying the separated coal into a plurality of groups having different particle sizes, 26 is a pulverized coal feeder which is connected to a classifier 23 and is interposed in a system for supplying pulverized coal to the upper reactor 12, and 27 is a classifier. It is a coarse coal feeder which is connected to the vessel 23 and is interposed in a system path for supplying coarse coal to the lower reactor 11.

Supply coal 1 in the coal gasifier having such a configuration
Is crushed by the crusher 2 to be crushed coal 3 and sent to the classifier 23. In the classifier 23, the pulverized coal is classified into the fine coal 24 and the coarse coal 25, the fine coal 24 is supplied to the upper reaction chamber 12 by the fine coal feeder 26, and the coarse coal 25 is the coarse coal feeder 27.
Is supplied to the lower reaction chamber 11. In order to satisfy the gasification reaction rate required from the type of coal in the classifier 23 and the operating conditions of the upper reaction chamber 12, a part 28 of the fine coal powder classified by the classifier 23 is returned to the crusher 2, The particle size of the pulverized coal 24 supplied to the upper reaction chamber 12 is adjusted. Hereinafter, the gasification of coal generated in the upper reaction chamber 12 and the lower reaction chamber 11 is similar to the conventional coal gasifier, although the reaction rate is different, but other char recovery and the lower char reaction chamber to the recovered char Is also the same as in the conventional coal gasifier, so detailed description will be omitted.

As described above, according to the coal gasifier of the present embodiment, the gasification reaction rate in the upper reaction chamber 12 increases,
The increase in the amount of char is suppressed. Further, since the gasification reaction is an endothermic reaction, the temperature rise of the upper stage generated gas 18 and the resulting melting of ash in the char are suppressed, and as a result, the processing capacity of the char feeder 21 is insufficient and the char recovery unit 19 The blockage problem is resolved.

Further, for example, when the particles are classified into four groups having different particle sizes, in consideration of the required gasification reaction rate, the first and second groups having a smaller particle size are the upper reaction chamber, the third and fourth particles having a larger particle size. The group is fed to the lower reaction chamber.

FIG. 2 is an explanatory view of a coal gasifier which is a second embodiment of the present invention. In FIG. 2, the parts having the same reference numerals as those in FIG. 1 are the same objects or the same as the parts shown in FIG. A part having a function is shown, and a point different from the first embodiment is that in order to satisfy the gasification reaction rate required from the type of coal and the operating conditions of the upper reaction chamber 12, the pulverized coal classified by the classifier 23 is By crushing a part 29 with the pulverizer 30 for fine powder, the particle diameter of the coal supplied to the upper reaction chamber 12 as fine coal 31 is adjusted to obtain fine coal 31.

In this way, the required gasification reaction rate can be obtained, and an increase in the amount of char and an increase in the temperature of the gas generated in the upper stage can be appropriately suppressed.

〔The invention's effect〕

According to the device of the present invention, the gasification reaction rate in the upper reaction chamber is increased, and the ash in the char generated due to the slow reaction rate of the gasification reaction in the upper reaction chamber is melted and adhered to block the char recovery device, The problem that the processing capacity of the char feeder is insufficient can be solved.

Furthermore, in the lower reaction chamber, a larger particle size gives an effect that the ratio of ash in coal taken out of the system as slag increases, and a unique effect that the amount of char in the crude purified gas can be reduced. Play.

[Brief description of drawings]

FIG. 1 is an explanatory view of a coal gasifier of a first embodiment of the present invention, FIG. 2 is an explanatory view of a coal gasifier of a second embodiment of the present invention, and FIG. 3 is a conventional coal gasifier. FIG. 1 …… Supply coal, 2 …… Crusher 4 …… Distributor, 7,8 …… Coal feeder 11 …… Lower coal reaction chamber, 12 …… Upper reaction chamber 13 …… Oxidizing gas, 19 …… Char recovery Equipment 21 …… Char feeder, 23 …… Classifier 26 …… Pulverized coal feeder, 27 …… Coarse coal feeder 30 …… Pulverizer for fine powder

Claims (1)

[Claims] 1. A coal gasification reaction chamber is composed of a lower reaction chamber and an upper reaction chamber, and the lower reaction chamber is charged with coal recovered from the gas generated in the upper reaction chamber and a gasifying agent. Supplying coal and char to gasify and discharging the ash in the coal and discharging as slag, while the upper reaction chamber, the upper coal and gasification agent with the gas and char generated in the lower reaction chamber introduced In the coal gasifier for separating and recovering char from the gas generated in the upper reaction chamber generated by gasifying the coal and char and circulating the recovered char to the lower reaction chamber to gasify the coal, and a coal crusher And a classifier that is connected to the crusher and classifies the coal after crushing into a plurality of groups having different particle sizes, and pulverized coal according to the particle size of the pulverized coal that is connected to the classifier is pulverized coal in the upper reaction chamber. The lower row And a supply means for coal to be supplied to the plurality of stages in the vessel, the coal gasifier, characterized in that it includes.