JPS6122154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for transferring slurry using a pump.

For example, when pumping slurry such as coal or iron sand from a slurry transport ship and discharging it ashore, if the slurry concentration is high, particles in the slurry may clog the slurry transfer piping, or the load on the pump motor may increase. Inconveniences such as excessive size may occur. For this reason, it is necessary to monitor the concentration of the slurry during transfer, but no method has been proposed that can easily measure the concentration of the slurry during transfer.

An object of the present invention is to provide a method for transporting slurry that can easily and reliably measure the concentration or density of slurry being transported, thereby suppressing the concentration or density of slurry below a certain value. .

In order to achieve the above object, the slurry transfer method according to the present invention measures the suction pressure and discharge pressure of the slurry transfer pump and the current of the pump drive motor, and calculates the slurry concentration or slurry density from these measured values. , characterized in that fresh water is supplied to the slurry when the slurry concentration or slurry density exceeds a certain reference value.

Embodiments of the present invention will be described below with reference to the drawings.

The drawing shows a part of the slurry landing equipment of a coal slurry transport ship, in which a high-pressure water injection nozzle 12 is provided at the bottom of each hold 11, and a slurry suction pipe 14 equipped with a slurry suction pump 13 is connected. The other end of the suction pipe 14 is placed at the top of the slurry storage tank 15. This tank 1
5 is connected to one end of a slurry transfer pipe 17 equipped with a slurry transfer pump 16. Pressure gauges 18, 19, 20, 21 are provided on the suction side and discharge side of the suction pump 13 and the transfer pump 16, respectively, and ammeters 22, 23 are provided on the drive motors (not shown) of these pumps 13, 16. These pressure gauges 18, 19,
20, 21 and ammeters 22, 23 are connected to an arithmetic and control unit 24 including a computer.
Fresh water supply pipes 25 and 26 are provided at the bottom of the hold 11 and at the top of the slurry storage tank 15, respectively, and operating valves 27 and 28 connected to the arithmetic and control unit 24 are attached to each of the fresh water supply pipes 25 and 26.

The coal slurry loaded in the cargo hold 11 of the above-mentioned transport ship is dehydrated to some extent during loading or during navigation, and when unloading at the unloading port, the coal slurry is loaded into the cargo hold 11.
High-pressure water is injected into this from a nozzle 12 at the bottom. The slurry to which an appropriate amount of water has been added in this manner is sucked into a suction pipe 14 by a suction pump 13 and collected in a tank 15, and then further pumped into a transfer pump 14.
6 and transferred to land through a transfer pipe 17.
Note that it is also possible to transport the coal slurry without dehydrating it and unload it as is.

During slurry transfer, the pressure gauge 2 of the transfer pump 16
0, 21 and the output signals of the ammeter 23 are continuously sent to the arithmetic and control unit 24.
calculates the slurry density ρ from these measured values as follows, and controls the opening and closing of the valve 28 of the fresh water supply pipe 26 of the tank 15 based on this result. That is, the current value of the pump drive motor measured by the ammeter 23 is A, the suction pressure of the pump 16 measured by the pressure gauges 20 and 21 is Ps, the discharge pressure is Pd, and the differential pressure between these is P= Pd−Ps, pump 1
The water head of 6 is H = Pρ, and the discharge amount of pump 16 is Q
Then, the current value A is expressed as a function of the discharge amount Q and the differential pressure P as shown in equation (1), and the discharge amount Q is expressed as a function of the water head H as shown in equation (2).

A=f(Q,P)...(1) Q=f(H)=f(P/ρ)...(2) In these equations (1) and (2), the unknowns are the slurry density ρ and the discharge amount Since the other values can be obtained directly from the above measured values, the slurry density ρ and the discharge amount Q can be calculated by solving equations (1) and (2). When the slurry density is higher than a certain reference value, the valve 28 is opened to supply fresh water to the tank 15, thereby reducing the slurry density. Further, when the slurry density becomes considerably smaller than the above reference value while the valve 28 is open, the valve 28 is closed and the supply of fresh water is stopped. In this way, the slurry density is kept below a certain value, and since there is a certain relationship between the slurry density and the slurry concentration, the slurry concentration is also kept below a certain value, and the transfer pipe 17 is not clogged with coal particles. There is no risk of excessive load being applied to the motor of the transfer pump 16. Note that, as described above, since the slurry density and the slurry concentration have a certain relationship, it is also possible to calculate the slurry concentration instead of the slurry density and control the opening and closing of the valve 28 in the same manner as above.

Further, the arithmetic and control unit 24 calculates the weight of coal flowing in the transfer pipe 17 per unit time (instantaneous transfer amount) by multiplying the slurry density or the slurry concentration by the discharge amount, and integrates this instantaneous transfer amount. Calculate the cumulative amount of coal transferred and display these values as necessary.

Also, during slurry transfer, the output signals of the pressure gauges 18, 19 and ammeter 22 of the suction pump 13 are continuously sent to the arithmetic and control unit 24, and similarly to the above, the arithmetic and control unit 24 is connected to the bottom of the hold 11. The valve 27 of the fresh water supply pipe 25 is controlled. In addition, hold 11
If the bottom or the suction pipe 14 is clogged with coal particles, the calculated value of the slurry density may become abnormally small or the measured values of the pressure gauges 18 and 19 may become abnormal. By detecting such an abnormal phenomenon and opening the valve 27 to supply fresh water to the bottom of the hold 11, clogging with coal particles is prevented.

Incidentally, a device similar to the above can be installed in a facility for loading coal slurry onto a transport ship, and similar control can be performed.

The slurry transfer method according to the present invention can be applied to transfers other than unloading and loading of coal slurry, and can also be applied to slurries other than coal.

As described above, according to the present invention, the concentration or density of the slurry can be suppressed to a certain value or less, and clogging of particulate matter in the slurry and overloading of the pump driving motor can be prevented. Furthermore, the concentration or density of the slurry can be easily and reliably measured using a pressure gauge and an ammeter.

[Brief explanation of the drawing]

The drawing is a schematic pipe diagram showing one example of an apparatus for carrying out the method of the present invention. 15...Slurry storage tank, 16...Slurry transfer pump, 17...Slurry transfer pipe, 20,
21... Pressure gauge, 23... Ammeter, 24... Arithmetic control device, 26... Fresh water supply pipe, 28... Operation valve.

Claims (1)

[Claims] 1 Measure the suction pressure and discharge pressure of the slurry transfer pump 16 and the current of the pump drive motor, calculate the slurry concentration or slurry density from these measured values, and determine if the slurry concentration or slurry density exceeds a certain reference value. A method of transferring slurry by means of a pump, sometimes characterized by supplying fresh water to the slurry.