JPH0687989B2 - Wet tube mill water cooling device - Google Patents

Description

The present invention relates to a cooling device for wet tube mill water injection, and more particularly to a coal-water slurry (hereinafter CW) produced by a wet tube mill.
M) refers to a cooling device for lowering the temperature.

[Conventional technology]

An example of manufacturing a conventional CWM will be described with reference to FIG. In FIG. 2, the raw coal fed into the bunker 1 is supplied by a predetermined amount by a coal feeder 2 to a wet tube mill (hereinafter simply referred to as a mill) 3. On the other hand, the mill 3 is supplied with a predetermined amount of water from the water tank 4 and a predetermined amount of additive from the additive tank 5, and is supplied with coarse grain slurry from a strainer 7 described later. The above-mentioned raw coal, water and additives charged into the inlet of the mill 3 are ground and mixed in the mill 3. At this time, the temperature of the slurry in the mill 3 rises due to the heat generated by the pulverization (the power of the powder has a large amount of heat, which is said to cause a substantial heat loss). In this way, the high temperature slurry flows from the mill outlet 11 to the sump tank 12 and the pump 6
Is boosted and sent to the strainer 7. The slurry that has passed through the mesh 8 of the strainer 7 passes through the second discharge section 10 and is stored in the CWM tank 14 as a product. On the other hand, the slurry containing coarse particles separated by the strainer 7 passes through the first discharge section 9 and is sent to the mill inlet to be re-ground.

[Problems to be solved by the invention]

When the high temperature slurry is introduced into the strainer 7, the water existing on the surface of the coal particles due to the surface tension easily separates from the coal particles during the operation of the strainer 7, and the water mainly passes through the screen (mesh) of the strainer 7. Then, the amount of water in the product slurry is increased, and not only a predetermined high-concentration slurry cannot be obtained, but also the coal particles in the vicinity of the screen surface increase and a viscous layer is formed. There is a problem that continuous operation becomes difficult.

In addition, when the slurry taken out from the strainer 7 is still in a high temperature state, the water in the slurry stored in the CWM tank 14 evaporates, the vapor is condensed in the tank, and the condensed water is stored in the CWM tank 14. A water layer is formed on the surface of the slurried slurry, and the thickening phenomenon of the slurry occurs. Therefore, there is a problem in that the characteristics of the slurry that supplies the product slurry from the CWM tank 14 to the combustion device such as the boiler fluctuates over time, making it difficult to transport the slurry by pipes.

Furthermore, if the slurry is in a high temperature state between the mill 3 and the CWM tank 14, the additive contained in the slurry deteriorates, which promotes alteration of the slurry and changes the slurry characteristics. .

In order to solve such a problem, a device for cooling the water supplied to the mill 3 is installed. FIG. 3 is a system diagram showing an example of a conventional mill water injection cooling device. In FIG. 3, the water control valve is passed through the inlet water pipe 18.
The water whose flow rate is controlled by 19 is the cooling tower.
It is cooled at 15, boosted by pump 20 and sent to the mill. In this mill water injection cooling device, cooling is performed using latent heat of vaporization of water due to contact between water and the atmosphere in the cooling tower 15, and the cooling temperature is determined by the atmospheric temperature. Furthermore, the range of temperature drop is -5 to-
Since it is as small as about 7 ° C, a large cooling temperature drop cannot be expected. Especially in summer, assuming that the atmospheric temperature is 30 ° C, the cooling water temperature is as high as about 23-25 ° C, which is not sufficient for cooling the slurry temperature.

FIG. 4 is a system diagram showing another example of a conventional mill water injection cooling device. In FIG. 4, the inlet water from the inlet water pipe 18 enters the water tank 4, is pressurized by the pump 20, and is supplied to the chiller unit 16 via the chiller unit inlet pipe 22.
It is cooled here and returned to the water tank 4 through the circulation pipe 23.
The cooling water is mixed with the supply water in the water tank 4 and sent to the mill 3 by the pump 21. Since the chiller unit 16 uses a refrigerant and electrically cools it, the cooling temperature does not depend on the atmospheric temperature. However, in the chiller unit 16,
If the amount of water circulation decreases, the water in the chiller unit 16 may freeze. In order to avoid such obstacles, the temperature difference between the inlet and outlet water in the chiller unit 16 is 5
Limited to ~ 8 ° C.

As described above, conventionally, when cooling a large amount of mill water, there is a problem in that the effect of decreasing the slurry temperature cannot be increased because the temperature drop width cannot be made large.

The object of the present invention is to solve the above-mentioned problems of the prior art,
It is an object of the present invention to provide a cooling device for mill pouring water capable of increasing the cooling temperature drop width of a large amount of mill pouring water and adjusting the temperature to a desired slurry temperature.

[Means for solving problems]

The present invention is attached to a water tank and stores cooling water from a water cooling device, provides an auxiliary tank for supplying the cooling water to a mill, and supplies a predetermined amount or more of cooling water in the auxiliary water tank. Communicating with the supply water in the water tank so that it can be mixed,
The water from the water tank is cooled by a water cooling device.

[Action]

The water supplied to the water tank is cooled by the water cooling device, the cooling water is stored in the auxiliary water tank, and a predetermined amount of the cooling water in the auxiliary water tank is supplied to the mill. A predetermined amount or more of cooling water in the auxiliary water tank is mixed with the supply water in the water tank due to overflow or the like, and this mixed water is cooled by the water cooling device. Therefore, water constantly circulates in the water cooling device, the auxiliary water tank, and the water tank, and the amount of circulating water does not drop extremely. Further, the cooling water in the auxiliary water tank is maintained at a desired temperature, and this cooling water is supplied to the mill.

Example of Invention

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing one embodiment of a cooling device for mill water injection according to the present invention.

In FIG. 1, an inlet water pipe 18 is connected to the water tank 4, and a water control valve 19 is installed in the middle of the inlet water pipe 18. Auxiliary water tank 17 is attached to water tank 4, and chiller unit 16 and auxiliary water tank 17 are circulation pipes.
Connected through 23. The overflow water in the auxiliary water tank 17 is successively introduced into the water tank 4. A pump 20 and a control valve are provided in the chiller unit inlet pipe 22 that connects the water tank 4 and the chiller unit 16.
26 is provided, and a pump 21 and a control valve 25 are provided in a mill inlet pipe 24 that connects the auxiliary water tank 17 and the mill 3.

In FIG. 1, the same components as those of the conventional example shown in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

Next, the operation of the mill water injection cooling device configured as described above will be described.

The water whose flow rate is controlled by the control valve 19 through the inlet water pipe 18 enters the water tank 4, is mixed with the overflow water from the auxiliary water tank 17, and is supplied to the chiller unit 16 by the pump 20. The water cooled in the cheer unit 16 enters the auxiliary water tank 17. A part of the water in the auxiliary water tank 17 is extracted by the pump 21, the pressure is increased, and the water is sent to the mill 3.

The water that circulates in the chiller unit 16 and the auxiliary tank 17 is used in the mill 3 in order to fully utilize the functions of the chiller unit 16.
It is set to double the amount of water injected into This amount is calculated and determined by the heat balance between the temperature of the supply water before being cooled by the chiller unit 16 and the temperature of the cooling water supplied to the mill 3. The auxiliary water tank 17 is cooled by the chiller unit 16. Only cooling water is introduced and this cooling water is supplied to the mill 3. Therefore, the temperature drop width of the cooling water supplied to the mill 3 can be made large. On the other hand, the temperature control of the cooling water is performed by the control valve 25 and the control valve 26. That is, by controlling the amount of water sent to the chiller unit 16 by the control valve 26, the ratio of the amount of water sent to the chiller unit 26 and the amount of water sent to the mill 3 can be arbitrarily selected, and the amount of cooling water overflowing from the auxiliary water tank 17 can be selected. Can be changed to adjust the temperature of the water in the water tank 4. As a result, the chiller unit 16
Since the inlet water temperature can be adjusted, it is possible to freely control the chiller unit 16 outlet water temperature, and hence the auxiliary water tank 17 and the water injection temperature to the mill 3. Cooling water adjusted to a predetermined temperature is supplied to the mill 3, and mixed and pulverized with the additive from the additive tank 5 and the raw coal from the bunker 1.

Since the system circulates water between the auxiliary water tank 17, the water tank 4 and the chiller unit 16 in this way, the amount of water circulated to the chiller unit 16 is insufficient, and there is an obstacle to freezing and cooling in the chiller unit 16. Therefore, the temperature difference between the inlet and outlet water of the chiller unit 16 can be increased, and since the chiller unit 16 cools the water, it does not depend on the atmospheric temperature.

〔The invention's effect〕

As described above, according to the present invention, the water temperature at the inlet of the mill can be significantly lowered, which allows the water to be taken out from the mill.
The temperature of CWM can be lowered. Therefore, (1) C
It is possible to prevent the occurrence of clogging due to a decrease in the WM strainer passing speed, and (2) avoid the thickening phenomenon during CWM storage.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a cooling apparatus for wet tube mill water injection according to the present invention, FIG. 2 is a system diagram of CWM manufacturing equipment, and FIG. 3 is an example of a conventional water cooling apparatus for wet tube mill water injection. FIG. 4 is a system diagram showing another example of a conventional wet tube mill water injection cooling device. 1 ... Bunker, 2 ... Carbon feeder, 3 ... Wet tube mill, 4 ... Water tank, 5 ... Additive tank, 7 ... Strainer, 8 ... Mesh, 12 ... Sump tank, 14 ... …
CWM tank, 16 ... Chiller unit, 17 ... Auxiliary tank.

Claims (2)

[Claims] 1. Cooling of wet tube mill water injection provided with a wet tube mill for mixing and pulverizing water from a water tank, an additive and a raw coal, and a water cooling device for cooling water injected into the mill. In the device, cooling water from the water cooling device is attached to the water tank, and an auxiliary water tank for supplying the cooling water to the mill is provided, and the auxiliary water tank is cooled to a predetermined amount or more. A cooling device for wet tube mill water injection, wherein water is communicated with the feed water in the water tank so that the water can be mixed and the water from the water tank is cooled by a water cooling device. 2. A first control valve is provided in the middle of a pipe connecting the water tank and the water cooling device, and a second control valve is provided in the middle of a pipe connecting the auxiliary water tank and the mill. The amount of cooling water mixed from the auxiliary water tank to the water tank can be adjusted by controlling the flow rate by the first control valve and the second control valve. Cooling device for wet tube mill water injection according to the item.