JP2643286B2 - Online method for measuring liquid density - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for reducing the density of a liquid containing a large amount of sludge.
The present invention relates to a method for continuous online measurement.

[Prior Art] In processes such as absorption and distillation, the density and specific gravity of an absorbing solution or a distillate are one of important factors in process management.

As one of such on-line continuous measurement methods of the liquid density, a measurement method using a vibrating density meter is known. In this measurement method, a vibration with a constant amplitude is given to a tubular vibrator filled with a liquid to be measured by an oscillator, and the frequency of the vibration of the liquid to be measured generated by this is calculated, and from the obtained frequency, This is for measuring the density of the liquid to be measured.

[Problems to be Solved by the Invention] The above-mentioned method has no problem when the number to be measured is relatively clear, and the density can be measured effectively. However, for example, in the absorption liquid in flue gas desulfurization equipment such as the desulfurization of sintering flue gas in a steel mill, a large amount of sludge such as Fe is contained. Sludge adheres to the vibrator. As a result, a measurement error increases, and accurate measurement cannot be performed.

Therefore, the sludge to which the vibrator has adhered must be frequently removed by washing or the like, which makes continuous online measurement impossible.

Accordingly, an object of the present invention relates to a method for continuously and accurately measuring the density of a liquid containing a large amount of sludge on-line.

[Means for Solving the Problems] The present invention provides a vibrator that oscillates with a constant amplitude by an oscillator in a conduit through which a liquid to be measured flows,
In a method in which a liquid having a constant amplitude is given to the liquid flowing through the conduit by the vibrator and the density of the liquid is measured on-line by the frequency of the liquid, the liquid is provided in the middle of the conduit upstream of the vibrator. A filter for collecting sludge therein is provided, a washing water supply pipe is provided in the conduit between the filter and the vibrator, and a washing water discharge pipe is provided in the conduit upstream of the filter. Connecting, further, a bypass pipe is connected to the conduit upstream of the washing water discharge pipe, and a liquid flowing through the conduit is discharged through the bypass pipe at a fixed period, and during that time, from the washing water supply pipe. Supplying wash water to the filter, removing sludge attached to the filter by the wash water,
Switching the supply of the cleaning water, supplying the cleaning water from the cleaning water supply pipe toward the vibrator, removing sludge attached to the vibrator by the cleaning water, and supplying the vibrator to the vibrator until the next measurement. Is characterized in that the supply of the washing water is continued.

Next, the method of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing one embodiment of the method of the present invention. As shown in FIG. 1, a vibrator 3 for applying a constant amplitude vibration to the liquid flowing in the conduit 1 by an oscillator 2 is provided in the conduit 1 through which the liquid containing the sludge to be measured flows. ing. Reference numeral 4 denotes a temperature measuring element provided in the conduit 1 near the vibrator 3 for measuring the temperature of the liquid flowing in the conduit 1.

A filter 5 for collecting sludge in the liquid flowing through the conduit 1 is provided in the conduit 1 upstream of the position where the vibrator 3 is installed. The function of the filter 5 is
Determined by the characteristics of the sludge to be collected.

A washing water supply pipe 6 is connected to the conduit 1 between the filter 5 and the vibrator 3. A first valve 7 is provided in the middle of the cleaning water supply pipe 6, and a second valve 8 is provided in the conduit 1 between the connection position of the cleaning water supply pipe 6 and the installation position of the vibrator 3. ing.

A washing water discharge pipe 9 is connected to the conduit 1 upstream of the filter 5. A third valve 10 is provided in the washing water discharge pipe 9.

A bypass pipe 11 is connected to the conduit 1 upstream of the connection position of the washing water discharge pipe 9. A fourth valve 12 is provided in the middle of the bypass pipe 11, and a fifth valve 12 is provided in the conduit 1 between the connection position of the bypass pipe 11 and the connection position of the washing water discharge pipe 9.
A valve 13 is provided.

Each of the first valve 7, the second valve 8, the third valve 10, the fourth valve 12, and the fifth valve 13 is connected to the control device 13 by a lead. The control device 13 controls opening and closing of each valve.

The second valve 8 and the fifth valve 13 are opened, and the first valve 7, the third valve 10 and the fourth valve 12 are closed. As a result, the liquid to be measured flows in the conduit 1 through the vibrator 3, during which the density of the liquid is measured by the constant amplitude vibration provided by the vibrator 3.

After performing the measurement according to the above for a certain period of time, the second bypass 8 and the fifth valve 13 are closed, and the first valve 7,
The third valve 10 and the fourth valve 12 are opened. As a result, the liquid to be measured is discharged through the bypass pipe 11, during which the washing water supplied to the conduit 1 through the washing water supply pipe 6 flows to the filter 5, and the sludge adhering to the surface thereof Are removed by washing and discharged through a washing water discharge pipe 9.

After removing sludge adhering to the surface of the filter 5 for a certain period of time in this manner, the third valve 10 is closed and the second valve 8 is opened. As a result, the washing water supplied to the conduit 1 through the washing water supply pipe 6 is discharged through the vibrator 3, and during this time, the sludge to which the vibrator 3 has adhered is washed out and removed. And, until the next measurement by the vibrator 3,
The washing water continues to flow toward the vibrator 3.

To resume measuring the density of the liquid after a certain period of time,
Close the first valve 7 and the fourth valve 12 and
Open the valve 13. As a result, the liquid to be measured flows in the conduit 1 through the vibrator 3, during which the density of the liquid is measured by the constant amplitude vibration provided by the vibrator 3.

The switching of the flow of the liquid to be measured and the washing water by the opening and closing of the pipes described above is automatically performed by the control device 13 at regular intervals. FIG. 2 is a diagram showing an example of such a period.

FIG. 3 is a graph showing the results of the continuous measurement of the liquid density for a certain period of time by the method of the present invention and the results of the measurement each time by a float-type measuring instrument. The results are shown by dotted lines, and the results are measured by the float type measuring instrument. As is clear from FIG. 3, the measurement result by the method of the present invention is not much different from the measurement result by the badge by the float type measuring device, and the accuracy is high.

[Effects of the Invention] As described above, according to the method of the present invention, the density of a liquid containing a large amount of sludge can be continuously and accurately measured on-line. In various desulfurization equipment, in the process of absorption, distillation, etc.,
Industrially useful effects are brought about, such as being extremely effective in measuring the density and specific gravity of an absorbent or distillate containing a large amount of sludge.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the method of the present invention, FIG. 2 is a diagram showing an example of a measurement cycle according to the method of the present invention,
FIG. 3 is a graph showing the results of measurement by the method of the present invention in comparison with the results of measurement on a badge. In the drawings, 1 ... conduit, 2 ... oscillator, 3 ... vibrator, 4 ... temperature measuring element, 5 ... filter, 6 ... wash water supply pipe, 7 ... first valve, 8 ... 2 valves, 9 ... washing water discharge pipe, 10 ... 3rd valve, 11 ... bypass pipe, 12 ... 4th valve, 13 ... 5th valve.

Claims (1)

(57) [Claims] An oscillator is provided in a conduit through which a liquid to be measured flows, wherein the oscillator oscillates with a constant amplitude by an oscillator, and the oscillator applies a constant amplitude vibration to the liquid flowing through the conduit. In the method of measuring the density online by the frequency of the, in the middle of the conduit upstream of the vibrator, provided a filter for collecting sludge in the liquid, the filter and the vibrator And a washing water supply pipe connected to the conduit upstream of the filter, and a bypass pipe connected to the conduit upstream of the washing water discharge pipe. The liquid flowing through the conduit is discharged through the bypass pipe at regular intervals, during which cleaning water is supplied from the cleaning water supply pipe to the filter, and the cleaning water is supplied to the cleaning water. Then, the sludge adhering to the filter is removed, and then the supply of the washing water is switched to supply the washing water from the washing water supply pipe toward the vibrator, and the washing water adheres to the vibrator. Characterized in that the sludge is removed and the cleaning water is continuously supplied to the vibrator until the next measurement.