JPH0324971Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a fluidized bed combustion apparatus, which has been improved to be able to separate and collect fly ash and unused carbon contained in combustion exhaust gas. The present invention relates to a fluidized bed combustion apparatus.

[Prior Art] A fluidized bed combustion apparatus that can efficiently burn coal is known. FIGS. 2 and 3 are system diagrams showing a schematic configuration of a conventional fluidized bed combustion apparatus.

In FIG. 2, 1 is a forced air blower, and air is supplied to a fluidized bed type combustion furnace 3 through a pipe 2. In FIG. The combustion furnace 3 has a gas distribution plate 4 installed therein, and is divided into an air chamber 5 and a fluidized combustion chamber 6. Air passes through the gas distribution plate 4 from the air chamber 5 and enters the fluidized combustion chamber 6, where the coal particles supplied from the coal particle supply pipe 7 are fluidized and combusted. 8 is an overflow pipe for fluidized media, combustion ash, etc.

The combustion exhaust gas is extracted from the top of the fluidized combustion furnace 3 along with fly ash and unused carbon, collected in a dust collector 9, and then desulfurized in a desulfurizer 10. An induction fan 11 is installed downstream of the desulfurization device 10 to attract combustion exhaust gas. The combustion exhaust gas that has passed through the induction fan 11 is released into the atmosphere from a chimney or the like.

In addition, in the apparatus shown in FIG. 3, the fluidized combustion furnace 3
Gas distribution plates are installed in two stages inside the gas distribution plate 4, and the air chamber 5 and the fluid combustion chamber 6 are divided by the gas distribution plate 4 on the lower stage, and the fluid combustion chamber 6 is divided by the gas distribution plate 4a on the upper stage. and a fluidized desulfurization chamber 6a. A desulfurizing agent such as limestone or dolomite is introduced into the fluidized desulfurization chamber 6a from a supply pipe 7a, contacts the combustion gas flowing into the fluidized desulfurization chamber 6a from the fluidized combustion chamber 6, and desulfurizes by adsorbing or absorbing sulfur oxides. will be held. The desulfurized combustion exhaust gas passes through the dust collector 9 and the induction fan 11 and is released into the atmosphere.

Note that in addition to the desulfurization equipment, an appropriate denitrification equipment may also be installed.

[Problems to be solved by the invention] By the way, when coal particles are subjected to fluidized combustion, carbon is generated in addition to fly ash at a rate of about 15% by weight of the fly ash. This fly ash can be used as a cement admixture, but as the carbon content increases, its commercial value decreases. On the other hand, since carbon itself generates thermal energy upon combustion, it is preferable to collect it and re-burn it.

However, in conventional fluidized bed combustion equipment, fly ash and unused carbon are collected in a mixed state in the dust collector.
The rate of contamination of unused carbon into the fly assembly increased, and it was also impossible to recover unused carbon.

[Means for Solving the Problems] The fluidized bed combustion apparatus of the present invention has two dust collectors installed in series to collect dust from combustion exhaust gas discharged from a fluidized bed type combustion furnace. Then, a separator is provided to receive the collected matter collected by the dust collector on the front stage side and to separate the fly ash and unresolved carbon. Further, the separator and the downstream dust collector are connected so that the flyash separated by the separator is introduced into the downstream dust collector.

This separator is a device that uses air blown into the separator to separate flyash and unprocessed carbon according to their specific gravity difference.In the present invention, a forced air blower is used as the air blown into the separator. The air supplied to the fluidized combustion furnace is separated and introduced into the separator. In addition, a flow rate adjustment valve and a pressure reducing valve will be installed in the piping for introducing air to the separator. Furthermore, a fixed throttle is provided in the piping connecting the separator and the downstream dust collector.

[Function] In the fluidized bed combustion apparatus of the present invention, the combustion exhaust gas from the fluidized bed combustion furnace is first introduced into the pre-stage dust collector, and is collected in a state where fly ash and unused carbon (dust component) are mixed. be done. The gas component from which the dust component has been separated is sent to a subsequent dust collector. Further, the dust components collected by the pre-stage dust collector are sent to the separator. This separator separates the flyash and unused carbon by air blown into the separator. That is, the bulk specific gravity of fly ash is usually about 0.4,
The bulk specific gravity of unburned carbon is about 0.6 to 0.7. Therefore, the fly ash is carried by the air blown into the separator, exits the separator, is introduced into the downstream dust collector, and is collected in the downstream dust collector. On the other hand, since the unused carbon has a large bulk specific gravity, it remains in the separator, is separated from the fly ash, and taken out as the unused carbon alone from the separator.

As described above, according to the fluidized bed combustion apparatus of the present invention, flyash with an extremely low carbon content can be obtained. Furthermore, it is possible to recover unused carbon and use it for re-combustion. According to the present invention, by selecting the opening degrees of the flow rate regulating valve, the pressure reducing valve, and the fixed throttle, it is possible to reliably fractionate according to the difference in specific gravity between the fly ash and the unprocessed carbon.

[Example] Examples will be described below with reference to the drawings.

FIG. 1 is a system diagram showing the configuration of a fluidized bed combustion apparatus according to an embodiment of the present invention. In FIG. 1, air from a forced fan 1 is introduced into a fluidized bed combustion furnace 3 through a pipe 2. In this fluidized bed combustion furnace 3, gas distribution plates 4 and 4a are installed in two stages, and an air chamber 5, a fluidized combustion chamber 6, and a fluidized desulfurization chamber 6a are defined in order from the bottom. Piping 2 is connected to this air chamber 5 from push-in fan 1 so that air can be supplied thereto. A supply pipe 7 for coal particles and an overflow pipe 8 for fluidized medium and combustion ash are connected to the fluidized combustion chamber 6, and a pipe 7a for supplying an appropriate desulfurizing agent such as limestone or dolomite is connected to the fluidized desulfurization chamber 6a. and their overflow discharge chamber 8a are connected.

In the present invention, dust collectors for receiving combustion exhaust gas from the fluidized combustion furnace 3 and collecting dust therein are installed in two stages in series. In this embodiment, the upstream dust collector 9a is a cyclone, and the gas components from which the dust components have been separated by the cyclone 9a are passed through the pipe 12 to the downstream dust collector (in this embodiment, the dust collector is a cyclone). house) 9b.
An attraction fan 11 is installed downstream of the baghouse 9b.

At the bottom of the cyclone 9a, the cyclone 9a
A pipe 13 is installed for extracting the collected material, and the tip of this pipe 13 is connected to the separator 1.
Connected to 4. Note that a rotary valve 15 is installed in the middle of the pipe 13, and is configured to be able to extract the collected material while maintaining airtightness within the cyclone 9a.

A pipe 16 is connected to the lower part of the separator 14, and the upstream side of the pipe 16 is connected to the pipe 2 via a pressure reducing valve 17 and a flow rate regulating valve 17a.
Air is blown into the separator 14 from the forcing fan 1 through a pipe 16. A pipe 19 equipped with a rotary valve 18 is connected to the bottom of the separator 14, and is configured so that carbon can be extracted from the bottom of the separator 14 while maintaining airtightness inside the separator 14. There is.

A pipe 20 is connected to the top of the separator 14, and the tip of the pipe 20 is connected to the pipe 12.
A fixed throttle 21 is installed in the middle of this piping 20.

In the fluidized bed combustion apparatus according to the embodiment configured as described above, air introduced into the air chamber 5 from the forcing fan 1 via the pipe 2 passes through the distribution plate 4 and enters the fluidized combustion chamber 6, and then enters the fluidized bed combustion chamber 6 through the supply pipe 7. Coal particles supplied from the coal particles are fluidized and combusted. Most of the generated ash is extracted from the fluidized combustion furnace 3 through the overflow pipe 8. On the other hand, the combustion gas passes through the dispersion plate 4b, accompanied by fine fly ash and carbon, and enters the fluidized desulfurization chamber 6a. And supply pipe 7a
It comes into fluid contact with the desulfurizing agent supplied from the factory and undergoes desulfurization treatment. The desulfurizing agent overflows from the pipe 8a and is extracted to the outside of the fluidized combustion furnace 3.

The combustion exhaust gas that has undergone this desulfurization treatment is introduced into the cyclone 9a, where carbon and fly ash are separated and collected. Then, the gas component is introduced into the baghouse 9b from the pipe 12. On the other hand, the mixture of unused carbon and fly ash collected by the cyclone 9a is extracted by the rotary valve 15 and introduced into the separator 14 through the pipe 13.

Into this separator 14, air from the forcing fan 1 is introduced into a piping 16, and an upward air flow is introduced into the unresolved carbon and fly ash introduced into the separator 14 through the piping 13. hits. As mentioned above, the bulk specific gravity of fly ash is usually about 0.4, and the bulk specific gravity of unprocessed carbon is usually about 0.4.
It is about 0.6 to 0.7. Therefore, among the fly ash and unused carbon introduced into the separator 14, only the fly ash with a small specific gravity is carried by the upward air flow and passes through the pipe 20 into the separator 14.
being taken outside. And the fly attachment is
It joins the gas from the cyclone 9a in the pipe 12 and is introduced into the baghouse 9b. The fly ash is collected in this baghouse 9b, and the clean combustion exhaust gas that has passed through the baghouse 9b is discharged to the atmosphere via an induction fan 11.

On the other hand, in the separator 14, unused carbon having a large specific gravity is stored at the bottom thereof.
This unresolved carbon is extracted from the pipe 19 by the rotorow valve 18. The recovered carbon is reused, for example, by being introduced into the fluidized combustion chamber 6 again.

In addition, in this embodiment, by selecting the opening degrees of the pressure reducing valve 17 and the fixed throttle 21, the separator 1
By adjusting the amount of air introduced into 4, it is possible to reliably separate flyash and unresolved carbon according to the difference in their specific gravity.

The device of the embodiment described above is an example of the present invention, and the present invention is not limited to the device of the embodiment illustrated above. For example, in the embodiment shown in FIG. 1, gas distribution plates 4, 4a are installed in two stages in the fluidized combustion furnace 3, and a fluidized desulfurization chamber 6a is defined by the upper gas distribution plate 4a. A desulfurization device may be installed separately from the fluidized combustion furnace 3. Further, a denitrification device may be incorporated into the device system. Furthermore, a cooler may be installed to lower the temperature of the combustion exhaust gas introduced into the baghouse 9b. In this case, it is preferable to install it downstream of the cyclone 9a and upstream of the junction of the pipes 12 and 20, but it may be installed at other locations.

Further, in the above embodiment device, the separator 14
As such, the air introduced into the separator 14 from the pipe 16 is in direct contact with the flyash and unresolved carbon introduced into the separator 14 from the pipe 13, but a gas dispersion plate is installed inside the separator 14. The separator 14 may be of a fluidized bed type, with a pipe 16 connected below the gas distribution plate. In the case of a fluidized bed type separator, unused carbon is extracted from the fluidized bed in an overflow manner, and fly ash is extracted from the top of the separator along with air.

Note that when the fluidized desulfurization chamber 6a is provided in the fluidized combustion furnace 3 and limestone, dolomite, etc. is introduced as a desulfurizing agent as in the above embodiment, the temperature inside the desulfurization chamber 6a is approximately 810 to 860°C. It is preferable to adjust the temperature so that

[Effects] As detailed above, according to the fluidized bed combustion apparatus of the present invention, fly ash and unused carbon can be collected separately. Therefore, it is possible to obtain a flyash with a high commercial value and extremely low content of unused carbon, and it is also possible to obtain effective use of thermal energy by re-burning unused carbon. According to the present invention, reliable fractionation can be performed according to the difference in specific gravity between fly ash and unprocessed carbon.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the configuration of a fluidized bed combustion apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are system diagrams showing the configuration of a conventional fluidized bed combustion apparatus, respectively. 1... Force fan, 2... Piping, 3... Fluidized bed combustion furnace, 4, 4a... Gas distribution plate, 5... Air chamber, 6... Fluidized combustion chamber, 6a... Fluidized desulfurization chamber, 7
... Coal particle supply pipe, 7a ... Desulfurization agent supply pipe, 9
a...Cyclone, 9b...Baghouse, 11...
...Attraction fan, 14...Separator, 15, 18...
Rotary valve, 17... pressure reducing valve, 21... fixed throttle.

Claims (1)

[Scope of claim for utility model registration] A fluidized bed type combustion furnace, a forced air blower that supplies air to the combustion furnace, a dust collector into which combustion exhaust gas is introduced from the combustion furnace, and a combustion exhaust gas from the dust collector. In a fluidized bed combustion apparatus equipped with an exhaust fan that induces dust, the dust collectors are installed in two stages in series, and
A separator is installed that separates fly ash and unresolved carbon by the difference in specific gravity using air blown into the separator, and the separator is connected to the dust collector on the previous stage so that the collected material can be introduced. The separator and the downstream dust collector are connected through a first pipe so that the fly ash separated by the air blower can be introduced into the downstream dust collector, and the air supplied from the forced air blower to the combustion furnace is separated. A fluidized bed combustion apparatus characterized in that a second pipe is provided for introducing the liquid into a separator, a fixed throttle is provided in the first pipe, and a flow rate adjustment valve and a pressure reducing valve are provided in the second pipe. .