JPS6075341A - Slurry producing apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slurry manufacturing device, particularly a wet mill,
coking coal supply means for supplying coking coal to the one-groove mill;
The present invention relates to a slurry IJ-4J production apparatus including at least a liquid supply means for supplying a powdered coal conveying body to the wet mill.

The fuel used in combustion equipment such as boilers includes 1 oil and LNG.
There are liquid fuels such as coal, and solid fuels such as coal. Coal-water slurry, which is made by suspending coal in water together with additives such as surfactants, is being considered for use as boiler fuel because it is easy to handle such as shafting and storage. This coal-water slurry is commonly referred to as CW rvi.

When CWM is directly combusted, the coal concentration is as high as about 60% by weight or more, and the particle size must be as fine as about 70 to 80% by weight passing through a 200 mesh (74 μm or less).

In this case, the CWM must also be a pumpable, stable, low viscosity liquid. The conditions for producing c w M4 M with high slug IJ-1/ME, low viscosity, and stability are: (1) adjustment of a wide particle size distribution to increase the degree of particle packing and increase the concentration; (2) Adding a dispersant to form a water film on the particle surface to charge it and disperse the particles among themselves to reduce the particle size.

When such CWM'f is manufactured continuously, a method using a continuous wet ball mill r is common.

FIG. 1 shows a system diagram of a CWM manufacturing apparatus d using a continuous wet ball mill. Coal A is supplied into the mill 3 from the bunker 1 via the coal feeder 2, and water B and additive liquid (surfactant liquid) C are supplied to the mill 3 from the respective tanks 4 and 5 through the respective pumps 6 and 7. supplied within. The C W M produced in Mi/I/3 is discharged into a slurry adjustment tank 8 and supplied to a coarse separator 10 by a pump 9 . The overflow on the screen 11 of this separator 10 is passed from the discharge port 13 to the coarse slurry collection pipe 14 (((
) is returned to the Himil 3, and P) is crushed. In this case, separation and pre-pulverization of coarse particles are indispensable because if coarse particles are mixed into the product, they may cause the nozzle of the burner tip to close or cause an addition of 1 d of unburned matter in the combustion device.

In this way, CWMf: is produced continuously, but in order to produce stable CWM with a predetermined particle size, high grindness, low viscosity, and a suitable slurry concentration in the mill 3. Maintain proper particle residence time fii! I (i
There is a necessity to do LLl and crush it. However, since the properties of the coal A supplied into the mill 3, such as particle size, moisture content, and pulverizability, change from time to time, the discharge port 1 of the coarse grain separator 10
The concentration, particle size, and viscosity of the product CWM taken out from 2 are also likely to fluctuate, resulting in a problem that makes it impossible to continuously produce high-quality CWMi.

Thus, for example, if the water content of the stone 14A suddenly decreases, the slud IJ-41A degree in the mill 3 increases, thereby increasing the viscosity. The increased viscosity restricts the movement of the balls within the mill 3, resulting in a reduction in grinding capacity. Therefore, the concentration of CWM at the inner mouth of the mill 3 is too high, the viscosity is high, and the particle size is coarse.

Along with this, the amount of circulation from the coarse particle separator 10 to the mill 3 increases. When the coarse slurry circulated to this mill overflows the screen 11, moisture is removed from the screen 11.
Since it falls from 1, the solid concentration increases. Therefore mill 3
The slurry concentration within the tank further increases. By repeating this process, the mill 3 is finally closed.

To prevent such defects and troubles,
There is a method of sampling at the outlet of the mill 3 to measure the sturdiness, particle size, and viscosity of the CWM, and feeding back the results to the mill operating input to control the mill operation. However, if the coal concentration as shown in Figure 1 is about 60%
Percentage high precision wet ball mill grinding C
In the WM manufacturing method, the residence time of CWM in the mill 3 is as long as 1 to 2 hours (including the 611 constant time for slurry concentration and viscosity, it is difficult to deal with fluctuations in the properties of the product due to changes in the properties of the coal). There is a problem that it takes at least 2 to 3 hours to process, making quality control difficult.Furthermore, Kono If CW
M, t)) There is no technology that can quickly scale up a 9 degree or particle size distribution flute online, and it must rely on a patch-type 6111 standard method such as a wet sieve machine.

Therefore, automatic control of the grinding system is extremely difficult in this case.

The object of the present invention is to eliminate the drawbacks of the above-mentioned rice processing technology and to provide a slurry production system that can continuously produce high-quality cwΔ4 without stopping the equipment.

In order to achieve this object, the present invention includes at least a wet mill, a raw coal supply means for supplying raw coal to the wet mill, and a liquid supply means for supplying a liquid for transporting pulverized coal to the wet mill, In a slurry manufacturing apparatus for producing a slurry containing pulverized coal by pulverizing the raw coal in the presence of the liquid, there is provided a detection means for detecting noise fluctuations of the wet mill, and a detection means for detecting the slurry constituent material based on a signal from the detection means. The present invention is characterized in that it is equipped with a flat membrane for adjusting the total supply amount.

FIG. 2 is an illustration xl showing an embodiment of the present invention.

Coal A is supplied into a mill 3 from a bunker 1 via a coal feeder 2. Water B and additive liquid (surfactant liquid) C are collected from respective tanks 4 and 5 by pump 6.7 into recovery tank 1.
5, mixed with the coarse slurry separated by the coarse grain separator 10 by a stirring ram 16, and supplied in a fixed quantity to the mill 3 via a slurry recovery pipe 14. The CWM produced in the mill 3 is stored in a slurry adjustment tank 8 and transported by a pump 9 to the coarse particle separation @ 10, and the CWM that has passed through the screen exit of the separator 10 is transferred to the outside of the thread through the discharge port to form slurry product 1. Transported as. The coarse slurry that does not pass through the screen 11 overflows the screen 11 and enters the recovery tank 15 through the discharge port 13.

C W Fvi 'g with such a system
In the coal production equipment, the particle size, moisture content, crushability, surface properties, etc. of coal A change from time to time, so the slurry concentration, viscosity, and particle size of the product sludge change, and as mentioned above, all the manipulated variables are adjusted appropriately to control side 1. Otherwise, problems such as the mill clogging and stopping will occur as described above.

The present invention is based on the fact that the sound from the mill 3 changes when the properties of the coal change, and a total of 19 i of noise is installed near the mill, and the strength of the sound and the total number of M waves υIll are determined.5. rL L,
, transmits the change to the control box 20, and further sends a signal from the control box to the drive mechanism 21 of the pump 6, adjusts the amount of water supplied to the mill 3, and controls the slud IJ-U degree and viscosity in the mill. It is.

Furthermore, the present invention specifically provides that when the properties of coal A change, the particle size of the mill 3 output changes, and as a result, the amount of circulation from the coarse separator 10 to the mill 3 changes. Focusing on the above, the supply amount by the pump 9 to the coarse particle separator 10 and the product flow from the coarse particle separator 10 ``Ak'' are determined as follows:
22 and 23, and the flow rate is measured by the control box 24.
Based on the difference, the actual circulating amount is determined, and based on this, a signal is sent from the control phase 24 to the drive mechanism 25 of the coal feeder 2 to adjust the amount of coal fed to the mill 3. A signal is sent to the drive mechanism 26 of the pump 7 to adjust the additive (?1ffl) corresponding to the coal feed h(), thereby controlling the retention time of the particles in the mill 3 and thus the slurry particle size at the outlet of the mill 3.

If the slurry production equipment is operated according to the method of the present invention described above (7b1), even if the properties of the coal A change, the slurry humidity, viscosity, and U-produced metal can be maintained at predetermined values and of good quality. CWM can be produced continuously.

In addition, in FIG. 2, 17 is a mill drive motor, and 18 is a torque meter.

FIG. 3 is a characteristic diagram showing the relationship between slurry concentration, viscosity, and sound from the mill obtained in a CWM manufacturing apparatus using a wet ball mill with an inner diameter of J5 m and a length of 12.5 m. In addition,
The hardness index (HGi) of the raw coal used in this experiment was 50, and the same raw coal was used in the experiment shown in FIG. 4, which will be described later. From this figure, it can be seen that as the slurry temperature increases, the slurry viscosity increases and the sound from the mill decreases. This is because when the viscosity of the slurry in the mill increases, the movement of the balls in the mill is suppressed. As a result, the grinding capacity of the mill decreases and the slurry particle size at the mill outlet becomes coarse. As is clear from this test result, there is a nearly proportional relationship between the slurry density in the V-mill and the noise. Therefore, if the amount of coal feed is constant, the amount of water fed to the mill can be controlled by monitoring the water emitted from the mill. ! :i1suruc
wivt cans can be manufactured.

Section 4 1 shows the relationship between the crushed melon slurry in the mill and the Jl (layer ratio) of the slurry product that passed through 200 mesosyu of the slurry (crude slurry) from the mill (Fig. 1). The line ■ in the diagram indicates the amount of coal fed per hour is 25
Kg, the line ■ is a characteristic line in which the amount of coal fed per hour is 35 Kf, and the line ■ is a characteristic line in which the amount of coal fed per hour is 70 Kf.

As is clear from the figure, even if the concentration of slurry in the mill is constant (viscosity is constant), if the amount of coal fed per hour is different, the amount of slurry product (i) and the amount of crude slurry will change. Weight ratio changes. This change in weight ratio indicates a change in the particle size of the crude slurry. From this, we focused on the fact that the amount of circulating coal to the coarse separator or lano mill depends on the particle size at the mill outlet. By setting the liquid volume 'kQ4, it is possible to control the residence time of coal particles in the oil in the mill and maintain the slurry particle size constant.

In general, as the amount of coarse slurry circulated from the coarse separator to the mill increases, the residence time of the slurry in the mill becomes shorter.As a result, the particle size of the coarse slurry becomes coarser. At the same time, the particle size distribution is biased towards the larger particle size and the distribution width becomes narrower.

FIG. 5 is a particle size distribution diagram of the crude slurry when the amount of coal feed is kept constant and the slurry is circulated. The horizontal axis shows the particle size, and the vertical axis shows the frequency. Note that curve IV is a characteristic curve when the circulation ratio is 1, curve 2 is a characteristic curve when the circulation ratio is 0.33, and curve 2 is a characteristic curve when the circulation ratio is 0. Note that, for convenience, the dotted line Vu indicates the grain 1 current distribution of the slough IJ-a product when the circulation ratio is 1.

The fine line spacing of the coarse particle separator (screen) used at this time was 500 μn. FIG. 6 is a characteristic curve diagram showing the classification efficiency of the screen. The horizontal axis shows the particle size, and the vertical axis shows the ratio of the retention of the coarse slurry returned to the mill 23 with respect to the imaginary J[1, of the coarse slurry.

From FIG. 5, it can be seen that when the circulation ratio is 1 (curve lv), the proportion of coal XSl with large particle sizes is high, and in comparison, the proportion of coal with small particle sizes is very small. Circulation ratio is 0.33
In the case of (curve ■), when the coal particles with large particle size approach a predetermined particle size of 500 μm or less, the VC1 distribution width becomes wider than when the circulation ratio is 1.

These results show that the properties of the crude slurry improve by reducing the circulation ratio.

For this reason, if the circulation ratio is set to about 0 to 0.5, it is possible to produce a slurry fuel that is practically acceptable for use in combustion equipment. Further, when the circulation ratio is set to about 0 to 0.degree.2, slurry fuel with very good properties can be produced.

As shown in FIG. 6, the classification efficiency of a coarse separator such as a wet vibrating screen is nearly perfect, and most of the particles larger than the width of the screen are returned.

The ratio between the amount passing through the screen and the amount circulating that does not pass through the screen is approximately constant, and the particle size distribution state of the slurry product is approximately equal to the particle size distribution state at the +17 exit.

In the above embodiment, the fluctuating noise of the mill was detected and the total amount of water supplied was adjusted based on the detection signal, but the amount of water supplied was adjusted based on the detection signal every time coal was supplied or (and) additives such as surfactants were supplied. It is also possible to combine it with the amount of water supplied to make U+'l.

Further, as in the embodiment described above, if detection of noise fluctuations in the mill is combined with monitoring of the amount of circulation from the coarse separator to the mill, the properties of the slurry can be controlled more accurately.

The gap for detecting noise fluctuations of the mill is determined in advance by determining the reference level and the range of variation t for that reference level, and determining whether or not the noise actually exceeds the reference level. If so, what is the difference f?
It is checked whether it corresponds to the illJJ width, and the total adjustment deviation of the supply amount of the slurry constituent material is corrected accordingly.

In this invention, the noise and vibration of the wet mill is detected, and the supply amount of slurry forming material is fully adjusted based on the detection signal.
The vibration of the wet mill during grinding also has a correlation with the slurry properties inside the mill. The properties of the slurry in the mill (
When the particle size distribution, particle size distribution, etc. changes, the speed of the balls in the mill on the road changes, and the degree of collision between the balls changes, which appears as a change in vibration. Therefore, by monitoring the vibration frequency of the mill, changes in the properties of the slurry in the mill can be ascertained, and the slurry composition can be adjusted based on the detection signal of the fluctuation in the number of cycles.

The present invention has the above-described structure, and the desired concentration,
Automatically generates slurry with characteristics such as viscosity and particle size distribution.
Moreover, manufacturing can be carried out with high productivity.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional slurry manufacturing device, Fig. 2 is a schematic diagram of a slurry manufacturing device according to an embodiment of the present invention, and Fig. 3 is the relationship between slurry IJ-m, slurry viscosity, and mill noise. Figure 4 is a characteristic diagram showing the relationship between slurry concentration and screen passing ratio, Figure 5 is a characteristic diagram showing the relationship between particle size and mill outlet particle size distribution, and Figure 6 is a characteristic diagram showing the relationship between particle size and mill outlet particle size distribution. FIG. 3 is a characteristic diagram showing the relationship between slurry ratio and slurry ratio returned to the mill. 2... coal feeder, 3... mill, 10...
... Coarse particle separator, 11 ... Screen, 1
9... Sound level meter, 20°24... Control box, 21, 25, 26... Drive 4fj, structure. Rin 1 Figure 4 Figure 2 Figure 3 Mill Slurry; ILL (amount%) Figure 4 Slurry 3jlLIL (tl1%)

Claims (1)

[Claims] At least a wet mill, a raw coal supply means for supplying raw coal to the wet mill, and a liquid supply means for supplying a liquid sound for conveying pulverized coal to the wet mill, In a slurry manufacturing apparatus for producing a slurry containing pulverized coal by crushing grapes, there is provided a detection means for detecting noise fluctuations of the wet mill, and a supply certificate adjustment means for adjusting the supply amount of slurry constituent materials based on a signal from the detection means. The slurry manufacturing equipment is equipped with t%m.