JPH0725391B2 - High-concentration coal / water slurry storage tank drying and adhesion prevention method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention is intended to prevent CWM from drying or being attached to the inner surface of a storage tank when high-concentration coal / water slurry (hereinafter referred to as CWM) is stored in the storage tank. Regarding how to prevent.

Conventional technology CWM, which has recently become popular as an alternative energy source for oil
The coal concentration and the surfactant addition rate differ depending on the type of coal, but in general, the target values are a coal concentration of about 70%, a viscosity of 1000 cp or less, and a surfactant addition rate of 1% or less.
This CWM has a low water content of about 30%, so if left in the atmosphere, it will dry from the surface of the CWM, making it difficult to handle as a fluid. Therefore, the CWM is stored in a storage tank (hereinafter referred to as a tank) and, if necessary, is taken out from an outlet at the bottom of the tank by a pump or the like.

Problems to be Solved by the Invention A general tank is made of iron and is coated mainly for rust prevention. When CWM is stored in this general tank, uneven parts provided for each purpose on the inner wall surface of the tank, such as protrusions by welding, mounting part of CWM monitoring instrument, CWM receiving port, outlet (discharging port) ), Etc., and the CWM stays in each place regardless of the drop in the liquid level or flows down from that place as a starting point, the tank wall surface is heated by the direct sunlight that illuminates the wall surface, and at each place. The accumulated and flowing CWM is rapidly promoted to be dried and adheres to the place.

The CWM that has adhered to each of the above locations and the inner wall surface of the tank by repeating the rise and fall of the CWM liquid level gradually increases its thickness without being removed.

Also, if the CWM liquid level remains stationary for a long period of time, drying progresses in the area where the CWM liquid level contacts the inner wall surface of the tank. CWM deposits remain on the inner wall of the tank.

The above phenomenon occurs, and these deposits gradually grow, dry, start to peel, and are removed due to external vibration and the like, which causes the CWM outlet and the pump to be blocked.
In addition, it is difficult to completely remove the adhered and dried CWM even if it is washed with water Jet, and the strong adhered matter remaining remains in the CW again.
It grows due to the storage of M and repeatedly loses, causing the aforementioned troubles.

The present invention proposes a method for drying and preventing a high-concentration coal / water slurry storage tank that can solve the above problems.

Means for Solving the Problems In order to solve the above problems, the present invention provides, in a storage tank, a protective liquid having a specific gravity lighter than that of water, a high boiling point, and a sparingly water-soluble protective liquid such as mineral oil. Put a small amount of kind,
After that, CWM is distributed under it.

Effect According to the present invention, the protective liquid is always present on the surface layer of CWM,
The protective liquid prevents water in the CWM from evaporating and prevents drying and solidification due to water evaporation. Further, the CWM existing in the vicinity of the inner wall of the storage tank is liable to solidify and adhere to the heat of the inner wall, but according to the present invention, when the storage level in the tank moves up and down, the protective liquid adheres to the inner wall and becomes CWM. Since it exists between the inner wall of the tank and the inner wall of the tank, CWM is prevented from adhering and solidifying.

Example 1 CW was performed using the tank 1 shown in FIG. 1 and FIG.
The surface drying acceleration situation of M2 was observed.

Fig. 1 adopts a method of injecting CWM2 from the upper part of the tank 1, and 3 is a supply pipe of the CWM2, which faces the upper part in the tank 1. Reference numeral 4 denotes a bellows hose connected to the supply pipe 3, an air vent hole 5 is formed in an upper portion of the bellows hose 4, and a float 7 with a collar 6 is connected to the lower portion thereof.
8 is a collar 6 of the float 7 as shown in FIGS.
The concave groove 8 is provided as a portion to which a guide rod 9 vertically provided between the upper and lower surfaces of the tank 1 engages. 10 is a liquid level gauge such as an ultrasonic level meter, 11 is a manhole, 12 is an air vent pipe, and 13 is a supply pipe to the boiler. 2 (a) and (b) show a method of injecting CWM2 from the lower part of the tank 1.

Then, liquid paraffin was used as the protective liquid 14 in the tank 1, CWM2 was injected, and the surface viscosity of the CWM2 was measured by a B-type viscometer. The result of this measurement is shown in FIG. As is clear from the figure, when the protective liquid 14 such as liquid paraffin is used, the drying of the CWM2 surface is suppressed.

Example 2 Liquid paraffin was previously applied to the inner surface of the tank 1,
After injecting CWM2 into it, a small amount of liquid paraffin (protective liquid) was floated on the surface of CWM2 and left in direct sunlight.
As a result of extracting CWM2, it was confirmed that there was no deposit on the inner wall surface of the tank 1. If the above liquid paraffin is not applied, a means such as application of resin-based paint, resin lining, or mirror finish is adopted instead,
It is preferable to reduce the concave protrusions on the inner wall surface of the tank 1 as much as possible. Moreover, even if the suction of the CWM2 liquid level is prevented, the liquid level gauge installed at the top of the tank 1, for example, the ultrasonic liquid level gauge, detects the lowest liquid level and works in conjunction with the supply pump to the boiler. good.

EFFECTS OF THE INVENTION As described above, according to the present invention, the protective liquid prevents water in the CWM from evaporating, and after the protective liquid is added, the CWM is added, so that the liquid surface moves up and down. As a result, the protective liquid adheres to the inner wall surface of the tank, thus preventing the CWM from adhering to the inner wall surface of the tank and eliminating the cause of blockage of the CWM outlet and pump.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention for a tank that supplies CWM from above, and FIGS. 2A and 2B are sectional views showing an embodiment of the present invention for a tank that supplies CWM from below, Fig. 3 is a line graph showing the measurement of the dry state of the CWM surface layer, Fig. 4 (a) and (b) are enlarged sectional views showing the main part of Fig. 1, and Fig. 5 (a) is a float. Is a plan view, and (b) is a sectional view taken along the line AA in (a). 1 …… tank, 2 …… CWM, 14 …… protective liquid

Front Page Continuation (72) Inventor Nobuo Yoshii 1-6-14 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (56) Reference JP-A-59-56044 (JP, A) (JP, U)

Claims (1)

[Claims] 1. A protective liquid, which has a specific gravity lighter than water, a high boiling point, and is poorly soluble in water, is previously written in a tank, and then CWM is stored under the liquid. Drying and adhesion prevention method for high concentration coal / water slurry storage tank.