JPH10103669A - Fuel nozzle clogging detector for fluidized bed furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus capable of finding the closure of a fuel nozzle before completion of warming of a fluidized bed furnace which includes the fuel nozzle for supplying into a furnace through a fuel conveyance pipe a pulverized fuel as fuel mixture gas using primary air for carrying the fuel. SOLUTION: The present fluidized bed boiler includes a fuel nozzle 7 for supplying a powdered fuel in a fuel hopper 1 to a fluidized bed 8 in a furnace as fuel mixed gas through a fuel conveyance pipe 5 using primary air for carrying a fuel, and a fuel nozzle purge gas line 13. A differential pressure switch 15 is provided on the fuel nozzle purge gas line 13 for detecting the closure of the fuel nozzle 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder feeder for a fluidized bed furnace such as a fluidized bed boiler.

[0002]

2. Description of the Related Art FIG. 2 is a system diagram showing an example of a fuel supply apparatus for a fluidized bed boiler as an example of a conventional fluidized bed furnace. In a fluidized bed boiler, fuel is transported by air, and powdered fuel is supplied from the furnace bottom into the furnace. The powdered fuel supplied from the fuel hopper 1 to the mixing device 3 by the fuel supply device 2 that controls the flow rate is transported by the primary air supplied from the primary air pipe 4 to the mixing device 3, and the fuel transport pipe 5 and the fuel nozzle 7 to a fluidized bed 8 in the furnace.

In the figure, reference numeral 6 denotes a fuel cutoff valve, 10 denotes a wind box, and 11 denotes a secondary air pipe. Reference numeral 14 denotes a fuel nozzle purge gas line 13 for preventing or releasing the blockage of the fuel nozzle 7.
This is a fuel nozzle purge valve provided in the fuel nozzle.

[0004]

In the fluidized bed boiler, a part or all of the fluidized bed 8 can be ignited while being fluidized by the heated secondary air so that the fuel can be ignited as a preparation before fuel injection. Warm to temperature.
Since the fluidized bed 8 is flowing during warming, the fluidized material flows back into the fuel nozzle 7 at the bottom of the furnace to block it.

To prevent this, a blockage preventing gas is passed from the purge gas line 13 through the fuel nozzle purge valve 14 during warming, and a method of confirming whether the flow of the purge gas is actually generated correctly in each of a plurality of fuel nozzles is provided. Absent.

Accordingly, when the warming of the fluidized bed boiler is completed and the primary air is ventilated into the furnace, the blockage is unknown until the fuel transfer pipe differential pressure is confirmed. It was necessary to stop and restart the fuel nozzle after releasing the clogging of the fuel nozzle.

The present invention relates to a fluidized bed furnace equipped with a fuel nozzle for supplying powdered fuel as a fuel mixture into the furnace through a fuel transfer pipe using primary air for fuel transfer. It is an object of the present invention to provide a device that can detect a blockage of a fuel nozzle at an early stage before the completion of the mining.

[0008]

According to the present invention, in order to solve the above-mentioned problems, equipment for detecting a flow such as a differential pressure switch is separately provided in a purge gas line for preventing blockage of a fuel nozzle for each fuel nozzle.

Since the fuel nozzle purge valve is opened before the fluidized-bed furnace is started, it is checked whether or not the purge gas has passed through the individual fuel nozzles when the operation is stopped, and the fuel nozzle is clogged. Can be determined. Therefore, if the fuel nozzle blockage is found at this time, the fuel nozzle blockage can be released by re-venting the purge gas without restarting the unit in the middle of the conventional operation.

Also, the purge gas is ventilated during warming. During this time, the presence / absence of the purge gas can be confirmed for each fuel nozzle, and the backflow (occlusion) to the fuel nozzle due to the sticking of the fluid material can be confirmed. Detection is possible, and it is possible to take measures to eliminate clogging of the fuel nozzle at an early stage.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fuel nozzle blockage detecting device for a fluidized bed furnace according to the present invention will be described in detail with reference to an embodiment shown in FIG. The embodiment shown in FIG. 1 shows an example in which the present invention is applied to a fluidized bed boiler.

In FIG. 1, powder fuel supplied from a fuel hopper 1 to a mixing device 3 by a fuel supply device 2 for controlling a fuel flow rate is conveyed by primary air introduced into the mixing device 3 from a primary air pipe 4. The fuel is supplied from the fuel nozzle 7 to the bottom of the fluidized bed 8 through the fuel transfer pipe 5 and the fuel cutoff valve 6. On the other hand, secondary air coming from the wind box 10 at the bottom of the fluidized bed 8 via the secondary air pipe 11 is supplied to the bottom of the fluidized bed 8.

A fuel nozzle purge gas line 13 is connected downstream of the fuel cutoff valve 6 provided in the fuel transfer pipe 5, and a fuel nozzle purge valve 14 and a differential pressure switch 15 are provided in the purge gas line 13. ing.

A flow switch may be provided in place of the differential pressure switch 15. Further, since a large number of fuel transfer pipes 5 are provided, a purge gas line 13 having a fuel nozzle purge valve 14 and a differential pressure switch 15 is connected to each fuel transfer pipe.

A purge gas N ₂ is supplied to the fuel nozzle 7 through a fuel nozzle purge valve 14 in order to prevent the fuel nozzle from being clogged during warming. At this time, the fuel cutoff valve 6 is closed.

When a purge gas flows into the furnace through the fuel nozzle 7 by opening the fuel nozzle purge valve 14, a differential pressure switch 15 provided in the fuel nozzle purge gas line 13 detects the gas flow and the fuel nozzle detects the gas flow. It is determined that it is not blocked.

Conversely, if the fuel nozzle is closed, the differential pressure switch 15 does not operate, and it can be determined that the fuel nozzle 7 is closed. When the fuel nozzle 7 is closed, the blockage can be eliminated by re-ventilating the purge gas line 13 thereafter.

As described above, the present invention provides a fuel nozzle for supplying powdered fuel as a fuel mixture using fuel-conveying primary air into a furnace through a fuel transfer pipe, and a fuel nozzle for preventing clogging of the fuel nozzle. In a fluidized-bed furnace having a purge gas line, a switch for detecting blockage of a fuel nozzle is provided in a purge gas line for preventing blockage of a fuel nozzle.

According to the present invention configured as described above, the clogging of the fuel nozzle can be detected at an early stage before the completion of the warming of the fluidized bed furnace, so that the unit must be stopped again during the start-up. It is possible to improve the reliability of the fluidized bed furnace and shorten the start-up time.

[Brief description of the drawings]

FIG. 1 is a fuel supply system diagram of a fluidized-bed boiler showing one embodiment of the present invention.

FIG. 2 is a system diagram showing an example of a conventional fuel supply device for a fluidized bed boiler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel hopper 2 Fuel feeder 3 Mixer 4 Primary air pipe 5 Fuel transfer pipe 6 Fuel cutoff valve 7 Fuel nozzle 8 Fluidized bed 10 Wind box 11 Secondary air pipe 13 Fuel nozzle purge gas line 14 Fuel nozzle purge valve 15 Fuel nozzle blockage detection Pressure switch for

Claims (1)

[Claims] 1. A fluidized bed comprising a fuel nozzle for supplying powdered fuel as a fuel mixture using a primary air for fuel transfer to a furnace through a fuel transfer pipe, and a purge gas line for preventing blockage of the fuel nozzle. A fuel nozzle blockage detecting device for a fluidized bed furnace, wherein a switch for detecting blockage of the fuel nozzle is provided in the purge gas line for preventing blockage of the fuel nozzle in the furnace.