JPS61231324A - Method of detecting and restoring fuel carrier tube - Google Patents

Abstract

PURPOSE:To early detect the blockage of a carrier tube by detecting the lowering of the carrier tube for carrying a gas to be carried. CONSTITUTION:The gas to be carried is kept at a temperature which is higher by 10-100 deg.C than the ambient temperature of a carrier tube 3 by means of a heater. On the surface of each carrier tube 3 is provided a temperature meter 14. The detected value with respect to an average value of a deviation between the measured value of the temperature meter 14 and the measured value of a temperature meter on the surface of the carrier tube connected to the same distributor or the detected value of a difference between the measured value of the temperature meter 14 provided in the carrier tube 3 and a deviation between the measured value of a temperature meter 8 provided on the surface of a carrier master tube 1, and the average value of the carrier tube connected to the same distributor, are out of a preset scope, it is looked upon as the blockage of the carrier tube and a blocking signal is emitted. A stop valve 15 is closed by the blocking signal and a switching valve 17 is opened, and a high-pressure gas for purging is caused to flow to the upstream side and downstream side of the stop valve 15 to push out the pulverized substance and to restore the tube to the original condition.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is a method for detecting blockages in fuel conveying pipes that convey powder particles such as pulverized coal and coke in an air stream and supplying them to combustion devices such as boilers and kilns. This relates to recovery methods.

[Conventional technology]

Conventionally, granular fuel such as pulverized coal is supplied from a normal pressure storage bunker or hopper to a pressurized airflow conveyance main pipe, and distributed to multiple conveyance pipes by °min cyn to be used in combustion equipment such as boilers and kilns. The method of supplying this is well known. This conventional method relies on visual inspection. Furthermore, the detected value of the pressure inside the conveying pipe may not be able to be detected depending on the position of the blockage.

[Problem that the invention seeks to solve]

When supplying solid fuel by pneumatic conveyance, increasing the solid-air ratio and reducing the diameter of the conveyor tube in order to increase conveyance efficiency may increase the possibility of clogging accidents in the conveyor pipe during conveyance. Pipe blockage is important from the viewpoint of combustion control. However, as the equipment becomes larger and the number of conveyor pipes increases,
It becomes difficult to check for blockages. Particularly in the case of a fluidized bed combustion boiler, even if a distributor with a high distribution ratio is used, there are many conveyor pipes in the vicinity of the boiler.

The present invention was made in view of the above-mentioned points, and an object of the present invention is to provide a method for early detection and restoration of conveyance tube blockage.

[Means and operations for solving the problem] The method for detecting and restoring blockage in a fuel conveying pipe according to the present invention will be explained with reference to FIGS. 1 and 2. In this method, the carrier gas is heated to a temperature 10 to 100°C higher than the ambient temperature of the carrier pipes 3, and the surface of each carrier pipe is A thermometer 14 is provided at The difference between the measured value of the thermometer 8 and the difference between the measured values and the measured value of the thermometer 14 provided in each conveying pipe 3 connected to the same distributor 2 and the measured value of the thermometer 14 provided in the conveying main pipe 1 thermometer 8
When the deviation from the average value of the measured value of The valve 15 is closed, and the on-off valves 17 provided upstream and downstream of the conveyance pipe stop valve are opened to blow high pressure gas leaking from the barge.

Note that there is some variation in the skewness of each conveying tube, and if the difference between the conveying gas and the ambient temperature of the conveying tube is less than 10° C., an erroneous signal will be generated, which is undesirable.

Furthermore, if the difference between the carrier gas and the ambient temperature of the carrier pipe exceeds 200°C, there is a risk that the properties of the carrier will change, and since the temperature is high, there will be a delay until it reaches a detectable temperature.
There is a problem that the detection time becomes long.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. Reference numeral 1 denotes a transport main pipe for airflow transporting powder and granular material, and a plurality of transport pipes 3 are branched from this transport main pipe 1 via a distributor 2. 4 is a blower that supplies pressurized gas to the transport main pipe 1, 5 is a heater using steam or the like as a heat source, 6 is an oil chamber, and the upper part of the bleed chamber 6 is connected to a powder storage bunker. There is.

7 is a damper, 8.10 is a thermometer, 11 is a flow control valve,
12 is a temperature control device, and 13 is a fluidized bed boiler.

In the apparatus configured as described above, the carrier gas is controlled by the heater 5 and the temperature adjustment device 12 at the ambient temperature of the carrier pipe 8 (
Try to keep it 10 to 100 degrees Celsius higher than the outside temperature. This temperature adjustment is performed by a thermometer 8 or 10 provided on the transfer main pipe 1.

However, since there is a slight temperature drop between the transport main pipe 1 and the transport pipe 3, this must be taken into consideration.

A thermometer 14 is provided on the surface of each conveying pipe 3 as shown in FIG.
is provided, and the deviation from the average value of the measured value of this thermometer 14 and the measured value of the thermometer on the surface of the conveying pipe connected to the same distributor, the detected value, or the thermometer 14 provided in the conveying pipe 3 The measured value and the thermometer 8 installed on the surface of the transfer main pipe 1
When the detected value of the difference between the measured value and the deviation from the average value of the conveyance pipes connected to the same distributor is out of a preset range, it is assumed that the conveyance pipe is blocked and a blockage signal is generated. A conveyor pipe stop valve 15 which is opened and closed by the blockage signal is provided in each conveyor pipe 3, and opening and closing valves 17 are provided upstream and downstream of the stop valve 15 and which operate according to the sequence determined by the blockage signal. A high-pressure gas blowing pipe 16 is provided for blowing in high-pressure air and the like. Of course, this recovery operation may be performed manually by obtaining a blockage detection signal.

Since the conveying gas no longer flows through the clogged conveying pipe 8,
The surface temperature decreases due to heat radiation to the surroundings. Therefore, blockage can be detected by monitoring the surface temperature of the transport pipe. As a monitoring method, if the surface temperature is easily affected by the ambient temperature, etc., it is appropriate to calculate the average value of the surface temperature of a specific group in the vicinity and calculate the deviation from that value. If the difference is large (specific transport pipe installation location,
(depending on the arrangement, operation (ON-OFF) mode of the conveyor tube, etc.), the measured value of each conveyor tube thermometer is monitored.

It is also an effective method to use the temperature difference between the transport main pipe 1 and the transport pipe 3 (branch pipe).

If the detected value is outside the preset tolerance range,
It is assumed that the conveyance pipe is blocked, but if blockage is detected, the stop valve 15 is closed based on a detection signal, and the on-off valve 17 is opened to flow high-pressure gas for purging to the upstream and downstream sides of the stop valve 15 simultaneously or separately. to push out the clogging powder and granules and restore the condition. It is effective to repeatedly and intermittently blow this high-pressure gas for purging. After performing a predetermined blockage release operation determined by a sequencer 20 built in the control device 18, etc., the injection of high pressure purge gas is stopped and the stop valve 15 is opened. 21 is a computing unit, and 22 is an alarm device.

In order to improve the detection accuracy of the above blockage detection system, the temperature of the carrier gas is controlled, and the detection end used for temperature control is installed as close as possible to the carrier pipe where blockage is to be detected. However, as seen in the example of using a fluidized bed boiler, when there are multiple conveyance lines and operation and stop are performed for each conveyance line, the temperature detection end is placed at the outlet of the heater 5, and the temperature detection end is placed at the outlet of the heater 5. The blockage detection judgment logic determines the surface temperature of the distributor inlet of each conveyance system,
The difference from the surface temperature of the transport tube is used as the above-mentioned surface temperature of the transport tube.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to reliably detect the blockage of the fuel transfer pipe, and also to effectively purge the blocked portion of the fuel transfer pipe to quickly recover the fuel transfer pipe. It has an effect.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is a detailed explanatory diagram of the distributor wheel in FIG. 1.

Claims (1)

[Claims] 1. In a method of supplying granular fuel to a combustion device via a transport main pipe, a distributor, and a plurality of transport pipes by pneumatic transport, the transport gas is heated to be maintained at 10 to 100°C higher than the ambient temperature of the transport pipe, A thermometer is installed on the surface of each conveyor tube, and the deviation between the measured value of one thermometer and the measured value of each other thermometer from the average value, the detected value, or the measured value of the thermometer installed on the conveyor tube and the conveyor base. The difference between the measured value of the thermometer installed in the pipe, and the difference between the measured value, the measured value of the thermometer installed in each conveying pipe connected to the same distributor, and the temperature installed in the conveying main pipe. When the deviation from the average value of the difference from the measured value of the meter is out of a preset range, it is assumed that the conveyance pipe is blocked and a blockage signal is issued. A method for detecting and restoring blockage in a fuel transfer pipe, which comprises closing a valve and opening on-off valves provided upstream and downstream of the transfer pipe stop valve to blow in high-pressure purge gas.