JPS6232596Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a coal crushing device, and particularly to a coal crushing device that can effectively prevent ignition within a pyrite box.

For example, in a large coal-fired boiler, coal is pulverized in a coal pulverizer (mill) and transported by air flow to a burner of the boiler for combustion. One type of mill is a vertical ball mill that uses balls to crush coal. This ball mill pulverizes coal by rolling the balls, supplies high temperature air into the device to dry the coal, and transports the pulverized coal to a classifier by air flow. In this case, some of the crushed coal and foreign substances such as sulfides that are not crushed fall to the bottom of the mill, so the fallen coarsely crushed coal (pyrite) is collected in a pyrite box and discharged outside the equipment. was. Since high-temperature air of around 200℃ is supplied to the mill, the pyrite in the pyrite box contains vaporized gas from the crushed coal, making it extremely easy to ignite, and there is a risk of ignition due to static electricity sparks, etc. There is. Furthermore, in a high-temperature atmosphere, pyrite generates highly ignitable gases such as methane as described above, which fills the poorly ventilated pyrite box, further increasing the risk of ignition.

The purpose of this invention is to provide a coal crushing apparatus which has been constructed in view of the above-mentioned problems, and which eliminates the risk of ignition within the pyrite box.

In short, this invention supplies cooling medium directly or indirectly to the pyrite box, and
In short, it is a coal crusher configured to supply inert gas into a pyrite box.

Examples of this invention will be described below.

FIG. 1 shows a vertical ball mill to which this invention is implemented, and first an outline of this ball mill will be explained. Coal 1 falls through the coal feed pipe onto the turntable 2 rotated by the motor 5, reaches the ball 3 due to the centrifugal force of the turntable rotation, and is crushed by the ball 3 rolling between the upper race 6 and the turntable 2. be done. The pulverized coal is heated with air 10 (usually at 200°C) supplied from the slit 11.
(high temperature air) that rises inside the device.
During this time, large-diameter particles collide with the primary classification plate 7, fall onto the turntable 2, and are re-pulverized. The remaining pulverized coal is given a swirling force by the guide vanes 8 and flows into the classification chamber 9. Here, classification is performed by the swirling force, and the pulverized coal flows into the pulverized coal pipe 4 along with the airflow and is transported to the burner by airflow. On the other hand, large-diameter particles descend within the classification chamber, fall onto the turntable 2, and are re-pulverized. In the above process, a part of the pulverized coal passes through the slit 11 and falls into the pyrite box 12, and the pyrite accumulated in the box is periodically discharged by opening the damper 13 and transported to the outside by the bucket conveyor 14. is discharged and mixed into coal 1. During this storage of pyrite, the problem of fire outbreak occurs as mentioned above.

FIG. 2 shows a first embodiment of this invention. In the figure, reference numeral 16 denotes a cooling gas box, and the cooling gas box 16 and the pyrite box 12 are separated by a ventilation plate 17 provided with a large number of small holes. The cooling gas box is configured to be supplied with cold air 15, or instead of or in addition to this cold air, inert gas 29 such as _N2 or combustion exhaust gas. By cooling pyrite, the generation of highly ignitable gas is minimized, and even if gas is generated, it is an inert gas29
By introducing this, fires can be almost completely prevented. In addition to the above structure, if a door body 30 is formed at the entrance of the pyrite box, it is possible to prevent hot air from flowing in from the crushing section and from escaping to the slit 11 side. pyrite can be retained therein, and it is easy to accept falling pyrite.

FIG. 3 shows an example of the structure of the door body 30.

Chute portion 12 forming a pyrite box
As an example, a is a chute having a rectangular cross section, and two shutter members 30a and 30b having sloped inner surfaces and facing edges at the center of the chute are provided.
The shutter member has a ``he''-shaped cross section and has a rotation shaft 131 at its bent portion, and is attached to the wall surface of the chute 12a for free rotation by pressing both ends of the shutter member with bolts 132. Chute 12a and rotation shaft 13
1 is kept airtight by an airtight member 32. Airtight member 3
Reference numeral 2 includes pressing plates 32a and 32b and an elastic airtight member 32d that contacts the outer periphery of the rotating shaft 131. The holding plates 32a and 32b have a plurality of long holes 32e (see FIG. 3C), and are fixed to the wall of the chute by adjusting their positions with mounting bolts 32c to maintain airtightness. The shutter members 30a and 30b are each made up of a door plate 31, a balance arm 33, and a balance weight 34, and are bent in an "E" shape, so the bending angle is particularly important, especially the inclination angle θ of the door plate 34 with respect to the chute wall surface. When selecting an appropriate distance from the axis of the rotation axis of the center of gravity G, the return speed (speed of returning to closing) after discharging the pyrite that has fallen onto the door plate downwards can be set appropriately. Can be done.

In addition, a seal box 40 is provided on the outside of the balance arm side chute wall, and the airtightness of the rotating shaft portion is further ensured by pressurized inert gas supplied to the pyrite box or pressurized inert gas from another inert gas supply source. Become something. This inert gas is supplied to the valve 39,
It is supplied via the nozzle 41. Furthermore, when the inert gas pressure inside the pyrite box 12 is made higher than the pressure above the door plate 31, the closing action of the door plate becomes faster and the opposing edges of the door plate 31 can be airtight. .

A water nozzle 35 is installed on the wall of the pyrite box, and when the temperature inside the pyrite box suddenly rises due to a signal from a temperature transmitter 36 and ignition is detected, a valve 38 is opened according to a command from a control box 37 to spray water into the pyrite box. It can also be given to extinguish the fire.

FIG. 4 shows the embodiment of FIG. In this embodiment, a cooling chamber 19 is formed in close contact with the wall surface of the pyrite box 12, and a cooling medium 18 such as water is supplied to this cooling chamber 19 to indirectly cool the pyrite. . In this embodiment as well, a door body 30 is formed at the entrance of the pyrite box 12, and an inert gas 29 is provided to the box.
It may also be configured to supply

FIG. 5 shows yet another embodiment, in which a purge gas port 23 is formed in the bucket conveyor 14, and a purge gas 22 is introduced into the bucket conveyor 14 to purge the flammable gas inside the conveyor.

The embodiments of this invention have been described above, but in addition to the above-described embodiments, ignition may be prevented by injecting water into the pyrite box or, in addition, to the bucket conveyor.

By implementing this invention, it is possible to effectively prevent the pyrite that has fallen into the pyrite box from igniting, so that the coal crushing equipment can be operated safely at all times.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a coal crushing device, FIG. 2 is a sectional view of a pyrite box showing a first embodiment of this invention, and FIG. 3A is a longitudinal sectional view of an embodiment of a door body.
FIG. 3B is a cross-sectional view along line AA in FIG. 3A, FIG. 3C is a perspective view of the holding plate 32a, FIG. 4 is a cross-sectional view of the pyrite box showing the second embodiment, and FIG. 5 is a view of the bottom of the bucket conveyor. FIG. 1...Coal, 12...Pyrite Box, 1
6... Cooling gas box, 17... Ventilation plate, 19... Cooling room, 29... Inert gas, 30... Door body.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a device in which pyrite that has fallen from the crushing section is collected in a pyrite box and then discharged to the outside of the crusher by a discharge device, a cooling medium that directly or indirectly cools the pyrite in the pyrite box is used. A coal pulverizer in which the cooling chamber to be supplied is formed in close contact with the pyrite box. 2. Scope of Utility Model Registration The coal pulverizer according to claim 1, wherein the cooling chamber is a cooling gas box attached to a pyrite box via a ventilation plate, and is configured to perform direct cooling with a cooling medium. 3. Scope of Utility Model Registration The coal pulverizer according to claim 1, wherein the cooling chamber is arranged in close contact with a pyrite box, and indirect cooling is performed using a cooling medium. 4. A coal pulverizer according to any one of claims 1 to 3 of the claims for utility model registration, in which a door body that opens and closes using fallen pyrite is attached to the entrance of the pyrite box. 5. A coal pulverizer according to claim 4 of the utility model registration, in which a pipe line for supplying inert gas is connected to a pyrite box. 6. A coal pulverizer according to any one of claims 1 to 5 as a utility model, which is equipped with a water nozzle that detects ignition in the pyrite box and supplies water spray.