JPH08292170A - Method for preventing stain on electrode of ph meter - Google Patents

Abstract

PURPOSE: To provide a method for preventing a stain on an electrode of a pH meter capable of suppressing a working load for maintenance and inspection of the pH meter by a method wherein a liquid to be measured is passed through a coke-filled layer having particles with specific diameters. CONSTITUTION: A liquid to be measured is introduced from a line 33 into a filter 1 wherein a coke-filled layer 10 is formed. A pollution material therein is removed during the passing through the coke-filled layer 10 having particles with 2-5mm diameters. The liquid to be measured which is cleaned is transported to a measuring tank 4 of a pH meter, then the pH measurement is sequentially executed. The coke-filled layer 10 consists of treated particle cokes of which particle diameter distribution is in the range of 4-8 mesh.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing contamination of electrodes when continuously measuring pH of industrial wastewater or reaction solution, and more particularly, p of wastewater containing pollutants such as oil.
It relates to a method suitable for being applied to H measurement.

[0002]

2. Description of the Related Art A pH meter measures by immersing a detection part (electrode) in a solution to be measured such as factory wastewater or reaction solution. It must remain immersed in the liquid to be measured. However, if the electrode is immersed in the liquid to be measured for a long time, contaminants in the liquid to be measured gradually adhere to cover the surface of the electrode, making it impossible to obtain accurate measured values.

Therefore, conventionally, the electrodes are cleaned or adhered by means of ultrasonic cleaning, water jet cleaning, chemical cleaning, or the like. For example, in the gas refining process of coke manufacturing equipment, the pH of the wastewater sent to the wastewater treatment device is measured, and the electrodes are cleaned by the chemical cleaning means at that time. FIG. 3 is an explanatory diagram of the method for measuring the pH of the waste water and the method for cleaning the electrodes. In FIG. 3, 30 is a decanter for spraying hot coke oven gas to rapidly cool the gas to separate tar content from the decanter, and 31 is ammonia for distilling and removing ammonia from the decanter 30. The stripper 34 is a steam blowing line.

The ammonia water from which ammonia has been removed by the ammonia stripper 31 becomes drainage (deaminated water), and the line 32
The water is sent to the waste water treatment equipment via a line, and at this time, a part of the water is taken out by the line 33 and sent to the pH meter 2 to continuously measure the pH.

Then, the electrodes are cleaned every predetermined time. When the electrode is washed, first, the lifting motor is activated to pull up the electrode 3 from the measurement tank 4, and the cleaning tank 20 filled with the chemical solution moves directly below the electrode 3. Next, the electrode 3 descends and is immersed in the chemical liquid, and the deposit is removed. After a lapse of a predetermined time, the reverse operation is performed and the pH measurement is restarted.

However, since the tar and pitch attached to the electrodes are not of a property that they can be easily removed, even if the electrodes are cleaned with a chemical solution, a measurement error will occur over time. For this reason, when the contamination of the electrode causes a measurement error, the electrode is manually washed and cleaned, and then the pH meter is calibrated.
The maintenance and inspection work of such a pH meter is performed several times a day.

[0007]

In the conventional pH measurement, the electrode is cleaned automatically every predetermined time, but it is not possible to keep the surface of the electrode clean for a long time. Have difficulty. In particular, in the pH measurement of the wastewater in the coke oven gas purification step, a small amount of tar or pitch is contained in the wastewater, and since the tar or pitch having a large molecular weight and adhesiveness adheres to the electrode,
It is difficult to remove the attached matter only by performing the electrode cleaning as described above. Therefore, it is often necessary to manually clean (clean) the electrodes. Furthermore, the pH meter must be calibrated in association with this electrode cleaning, which requires much labor for maintenance and inspection of the pH meter.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to provide a method for preventing contamination of a pH meter electrode, which can reduce the work load required for maintenance and inspection of the pH meter. And

[0009]

In order to achieve the above object, in the present invention, a coke having a particle size of 2 mm to 5 mm is filled with the liquid to be measured before introducing the liquid to be measured into a pH meter. Pass the layers.

[0010]

As described above, if the pollutant in the measured liquid adhering to the electrode is tar, pitch, etc., the electrode cannot be kept in a clean state simply by performing automatic cleaning with the chemical liquid. . Therefore, in the present invention, before sending the measured liquid to the pH meter, the pollutant contained therein is removed to bring it into a clean state, and the cleaned measured liquid is sent for pH measurement. For this reason, when measuring pH, the liquid to be measured is first sent to the coke packed layer, where the pollutants are captured by adhering to or adsorbing on the coke.

The coke for forming the coke filling layer is
The particle size should be within a certain range. It is not preferable that the coke has a particle size of 5 mm or more because the pollutant capture rate is low and the cleanliness of the measured liquid does not increase. When the liquid to be measured contains a relatively large amount of pollutants such as wastewater generated from the coke oven gas refining process, the coke has a particle size of 2 mm or more. Is desirable. When the wastewater from the above coke oven gas purification is passed through the coke packed bed, the wastewater also contains sludge and the like in addition to tar and pitch. At this time, if the particle diameter of the coke is 2 mm or less, the adhesion of the coke packed bed inlet portion, which first begins to adhere, occurs rapidly, and the inlet portion is clogged. For this reason, the coke filling layer becomes unusable even though the entire coke filling layer is not clogged.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an illustration of a method for preventing stains on a pH meter electrode according to the present invention. In FIG. 1, 1 is a filter filled with coke, 2 is a pH meter, 3 is an electrode, and 4 is a measuring tank. Reference numeral 11 is a wire mesh that partitions the inside of the filter 1. Coke dust is filled in the filter 1 to form a coke filling layer 10. The coke is sized so that the particle size distribution is 2 to 5 mm.

The liquid to be measured introduced into the filter 1 through the line 33 is a clean liquid in which contaminants are removed while passing through the coke-packed layer 10 and becomes a clean liquid.
Sent to. Then, the pH is continuously measured.

(Example) FIG. 2 is an explanatory view of a method for measuring pH of waste water generated from a coke oven gas refining process by applying the present invention. The result of performing pH measurement by this method will be described. Line 33 for sending wastewater to the pH meter
A filter 1 filled with powder coke having a diameter of 2 to 5 mm was attached in the middle of, and the pH of the wastewater was measured. Note that FIG.
1 that have the same reference numerals as those in FIG.
Since it has already been described, the description thereof will be omitted.

As described above, when the wastewater passed through the filter 1 was sent to the pH meter and the pH measurement was continued,
The degree to which the electrodes are contaminated has been reduced, and the time taken for the electrodes to become contaminated requiring manual cleaning has been significantly extended. Therefore, the frequency of maintenance and inspection work such as manual electrode cleaning and accompanying pH meter calibration work, which has to be carried out, is greatly reduced. Comparing the frequency of maintenance and inspection work of such a pH meter with that of the conventional chemical cleaning method, in the case of the conventional method, the above-mentioned maintenance and inspection work must be performed about twice / day. On the other hand, in the case of the embodiment, the maintenance and inspection work may be performed once every 3 days to once every 4 days.
Reduced to 7.

[0016]

According to the present invention, since the liquid to be measured is passed through the coke packed layer before the liquid to be measured is introduced into the pH meter, the pollutant contained in the liquid to be measured is contained in the coke packed layer. The liquid to be measured is introduced into the pH meter after being captured and removed by the pH meter in a clean state. For this reason, the progress of the contamination of the electrode becomes very slow, and the frequency of maintenance and inspection of the pH meter is greatly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method for preventing stains on a pH meter electrode according to the present invention.

FIG. 2 is an explanatory diagram of a method of applying the present invention to measure pH of wastewater generated from a coke oven gas purification step.

FIG. 3 is an explanatory diagram of a method for measuring pH of wastewater generated from a conventional coke oven gas refining process and an electrode cleaning method.

[Explanation of symbols]

 1 filter 2 pH meter 3 electrode 4 measuring tank 10 coke packed bed

Claims (1)

[Claims] 1. A method for preventing contamination of a pH meter electrode, which comprises passing the measured solution through a coke packed layer having a particle size of 2 mm to 5 mm before introducing the measured solution into a pH meter.