JPH0448697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a collection device for powder and granular materials, and particularly to a device intended to improve collection efficiency.

For example, large boilers for power plants are equipped with dust collectors to remove ash and other dust from the combustion gas, but in addition to this, denitrification equipment,
Hoppers are also formed in energy savers, air preheaters, etc. to remove dust by inertia. The dust collected in these dust collectors and each hopper section is collected in a collection section such as a silo by a collection device. The dust is collected through the hopper section of each device and the pipe line connected to the hopper section of the dust collector, and is sucked into the cyclone separator side and concentrated in the collection section. Conventionally, this recovery was done by operating a vacuum blower (suction type blower) at a constant rotation speed, detecting the degree of vacuum in the recovery line, and adjusting the opening degree of the damper in each hopper section in accordance with this degree of vacuum. It was controlled by. However, in this method, the control range of the air flow rate is narrow, and it is difficult to keep the mixing ratio (amount of recovered powder/granular material/mass of conveyed air) constant. When the mixing ratio increases, the dust recovery time increases due to the insufficient amount of conveying air, and there is also a risk of dust clogging in the line. On the other hand, when the mixing ratio decreases, the gas velocity in the line becomes higher than the set value, and wear in the line increases.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a powder and granular material recovery device that is configured to maintain a proper mixing ratio at all times.

In short, this invention calculates the mixing ratio of the gas containing the powder by detecting the amount of powder and granules discharged from each hopper and the flow rate of gas after separating the powder and granules. The rotation speed of the vacuum blower is controlled so that an appropriate mixing ratio is maintained at all times.

Examples of the present invention will be described below.

In FIG. 1, 1, 2, 3, and 4 are dust hoppers attached to a dust collector, a carbon saver, a denitrification device, etc., and each hopper contains collected dust. Reference numeral 5 denotes a powder transport pipe, and numerals 6, 7, 8, and 9 designate ejectors provided in this pipe, which are connected to each of the hoppers 1 to 4 to transport the dust in the hopper with air flow. 10, 11, 12, and 13 are measuring instruments that measure the amount of dust discharged from each hopper, and these measuring instruments are connected to a control box 14 that stores and issues command signals.
is connected to the signal circuit. 15 is a cyclone separator; 17 is a dust storage tank attached to the cyclone separator; 16 is an air pipe line for sucking the air from which dust has been separated in the cyclone separator 15; 18 is a vacuum blower provided in this air pipe line;
9 is a flow meter provided in this conduit. The control box 14 receives the signal from the flowmeter 19 and is connected to both of them by a signal circuit so as to control the rotational speed of the motor 18a of the vacuum blower 18.

In the apparatus having the above configuration, the amount of dust discharged from each of the dust measuring devices 10 to 13 is input to the control box 14. On the other hand, the flow rate of the air from which dust has been separated in the cyclone separator 15 is inputted from the flow meter 19, and the gas in the powder transport pipe 5 on the upstream side of the cyclone separator 15 is determined by the amount of dust discharged and this air flow rate. Calculate the mixing ratio of Based on the result of this calculation, the control box 14 controls the vacuum blower 1.
8 to adjust the amount of air to be absorbed, thereby maintaining the mixing ratio in the powder transport pipe 5 at an appropriate value. In addition, cyclone separator 1
The dust separated by 5 is stored in a dust storage tank 17 and discharged as appropriate.

Although the above description has been made using dust collected from exhaust gas as an example, the present invention is not limited to this, and can be carried out more effectively on other powder or granular materials.

By carrying out this invention, the mixing ratio in the line for supplying powder and granules can be maintained at an appropriate level at all times, thereby preventing clogging of the line and greatly reducing wear on the line.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an apparatus according to the present invention. 5... Powder transport pipe, 10, 11, 12, 1
3... Powder measuring instrument, 14... Control box, 15...
Cyclone separator, 18... Vacuum blower, 19...
...Flow meter.

Claims (1)

[Scope of Claims] 1. In an apparatus in which powder and granules are sucked by a vacuum blower and transported by air flow, and the powder and granules are separated by a separator, the amount of powder and granules discharged is A measuring device is installed to measure the flow rate of the vacuum blower, and a measuring device to measure the gas flow rate is installed in the piping downstream of the separator, and the vacuum blower is adjusted based on the mixing ratio determined from the amount of powder discharged and the gas flow rate. A powder and granular material collection device characterized by being configured to control the rotation speed and maintain an appropriate mixing ratio in a powder and granular material transport pipe. 2. The powder and granular material recovery device according to claim 1, wherein the control is performed by a control box that stores and issues command signals.