JPS59208436A - Method for detecting leakage of ammoniacal liquor into cooling water - Google Patents

Abstract

PURPOSE:To detect the leakage of ammoniacal liquor into cooling water, by using a detector for cyanogen in water in which a silver ion electrode is used as a detecting electrode, and utilizing the fact that an abnormality high potential is indicated when a potential is measured in a water to be detected wherein hydrogen cyanide and hydrogen sulfide are commonly contained. CONSTITUTION:When a cooling pipe 14 in an ammoniacal liquor cooler 13 is broken by the causes such as corrosion and the ammoniacal liquor leaks into the cooling water, the ammoniacal liquor passes through a cooling water pipe 5 and flows into a COG cooler 1. Since hydrogen cyanide and hydrogen sulfide are included in the ammoniacal liquor, a detector 19 for cyanogen in water, which is provided in the COG cooler 1, detects HS<->, detects the change in potential, and performs meter indication. Based on the signal from the detector 19, a warning indicator is operated, the buzzer of a warning unit is sounded, and a warning lamp is lighted.

Description

[Detailed description of the invention] The present invention relates to a method for detecting ammonium water leakage into cooling water.

Coke oven gas (hereinafter referred to as
COG (also referred to as COG) is purified and used as refined coke oven gas for fuel, etc., but the refining process includes a tar separation process, and indirect cooling and direct cooling are performed during this tar separation. Indirect cooling refers to cooling COG with cooling water without contacting each other. For example, COG
Cooling water is passed through the inside of the cooling pipe and cooling water is passed outside the cooling pipe, and seawater is usually used as the cooling water. Direct cooling is performed as the next step after indirect cooling, and is performed by pouring ammonium water (water containing a large amount of ammonia, which is produced by condensing the moisture entrained in COG when COG is cooled) onto the COG. This is what we do.

In direct cooling, ammonium water that is poured down and collected at the bottom of the COG cooler is led to the ammonium water cooler, cooled by cooling water, and circulated as COG cooling water. The cooling pipes of the equipment may be damaged due to corrosion, etc. In this case, the liquid pressure inside the ammonium water cooler is greater in the ammonium water than in the cooling water, so slight damage to the cooling pipes may occur. However, there is a risk of cheap water leaking into the cooling water.

The present invention was made in view of the above points, and when ammonium water leaks into cooling water due to a breakage of a cooling pipe, an underwater cyanide detector is used to detect the leakage of the ammonium water at an early stage, and to detect harmful substances. The aim is to prevent wastewater from being discharged into the sea, etc.

That is, the present invention provides a method for detecting leakage of ammonium water into cooling water due to breakage of a cooling pipe in a tank used for directly cooling coke oven gas and indirectly cooling Kuan water with cooling water. Ammonium water leakage into cooling water characterized by measuring hydrogen sulfide concentration using an underwater cyanide detector using a silver ion electrode as an electrode, and detecting ammonium water leakage into cooling water from the change in concentration. It depends on the detection method.

The present invention detects leakage of ammonium water by using an underwater cyanide detector using a silver ion electrode as a detection electrode. in this case,
Ammonium water contains hydrogen sulfide as well as hydrogen cyanide.
Since this hydrogen sulfide interferes with cyanide concentration measurement, the cyanide concentration cannot be directly detected.

The present invention uses an underwater cyanide detector that uses a silver ion electrode as a detection electrode to measure the potential in test water where hydrogen cyanide and hydrogen sulfide coexist, and takes advantage of the fact that it shows an abnormally high potential. The cyanide concentration in the cooling water is estimated by detecting the leakage of ammonium water into the cooling water and measuring the amount of ammonium water leakage.

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

FIG. 1 shows the cooling process of COG. The cooling process consists of indirect cooling and direct cooling, 1 is a COG cooler used for indirect cooling, and 2 is a COG cooler used for direct cooling.
The cooler is shown. The COG is guided through the COG conduit filter into a cooling pipe 4 in the cooler 1, and as it passes through the cooling pipe 4, it is cooled by cooling water 6 flowing into the cooler 1 through a cooling water pipe 5. The COG that has left the cooler 1 passes through the COG conduit 7 and enters the cooler 2, where it is cooled by ammonium water 8 that is poured from above the cooler 2.
It passes through the COG conduit 9 and is sent to the next process, for example, a naphthalene removal process.

The ammonium water flows into the cooler 2 from the ammonium water conduit 10 and is poured from above, and the ammonium water used for cooling flows out from the lower part of the cooler 2 through the ammonium water conduit 11 and circulates through the gear pump 12, etc. A mechanism guides it again to the upper part of the cooler (2), where it is used for circulation. An ammonium water cooler 1δ is installed in the middle of this circulation system. The ammonium water pumped by the gear pump 12 enters the cooling pipe 14 of the cooler 13, and as it passes through the cooling pipe 14, it is cooled by the cooling water 16 flowing through the cooling water conduit 15 and into the cooler 16. cooled down. Cooling water 16 used for cooling cheap water
The water is led to the cooler 1 for indirect cooling of the COG through the cooling water conduit 5, and is used for indirect cooling of the COG as described above. It will be swept into public waters via Ditch 18. The cooling water 1
6 is usually seawater.

The temperature of COG fed through COG conduit 6 is approximately 80C.
Therefore, the COG is 55 to 60tZ' depending on the cooler 1.
It is further cooled to about 30C by cooler 2.

The temperature of ammonium water 8 is 31 to 33C after being used as cooling water, and the ammonium water is cooled to 27 to 29C by cooler 1δ.

Reference numeral 19 denotes a known underwater cyanide detector (4) installed in the cooler 1, and the detector 19 is installed with its tip immersed in the cooling water in the cooler 1.

The detector 19 has a structure in which the detection electrode and the reference electrode are covered with an internal liquid by a diaphragm, and a silver ion electrode is used as the detection electrode, and Ag(ON)t- is used as the internal liquid. The diaphragm has the property of permeating hydrogen cyanide gas, and when the tip of the detector is immersed in water containing hydrogen cyanide, the hydrogen cyanide gas purged into the gas phase permeates inside and reacts with the internal liquid, resulting in The structure is such that a potential change occurs in the sensing electrode, and this potential change is detected to provide meter indication.

If hydrogen sulfide is present in addition to hydrogen cyanide in the test water,
Similarly, as H8'' reacts with the internal solution, a potential change occurs, but the potential at this time is about 1000 times higher than that of hydrogen cyanide alone.Therefore, direct CN- detection is not possible. However, since H8- detection can be performed, in test water where hydrogen cyanide and hydrogen sulfide coexist, I(S- detection is performed, and therefore C
It is possible to infer the existence of N-.

The underwater cyanide detector 19 can be provided with a known alarm mechanism. For this purpose, an amplifier, an indicator alarm, and an alarm unit are normally connected to the underwater cyanide detector 19 in this order.

If the cooling pipe 14 of the ammonium water cooler 13 is damaged due to corrosion or the like and the ammonium water leaks into the cooling water, this ammonium water flows into the COG cooler 1 through the cooling water conduit 5. Since ammonium water contains hydrogen sulfide as well as hydrogen cyanide, the underwater cyanide detector 19 installed in the COG cooler 1 detects H8-, detects potential changes, and gives meter indications.
The indicator alarm is activated by the signal from the detector 19, the buzzer of the alarm unit sounds, and the alarm lamp lights up.

This alarm action closes the valve 20 of the cooling water conduit 17, stopping the cooling water containing ammonium hydroxide from being discharged into the drainage ditch 18, thereby preventing the cooling water from being discharged into the public sea area.

The underwater cyanide detector 19 is installed at a COG for indirect cooling.
It is not limited to the cooler 1, and may be installed in the ammonium water cooler 15, or may be installed at any location in the cooling water conduit 5.

Experimental examples are shown below.

Example seawater 1? Add 5oz, 10oz of ammonium water to P/, respectively.
Test water mixed with 150t and 2oot was prepared, and the potential (mV) of each was measured using an underwater cyanide detector. The results are shown in Figure 2. In the figure, the ``amount of ammonium chloride mixed into seawater'' on the vertical axis means ``amount of ammonium chloride leaked into seawater.'' The estimated cyanide concentration calculated from the amount of ammonium water mixed in (ammonium water leakage amount) (the cyanide concentration in ammonium water is assumed to be 500 PPM) is shown on the upper horizontal axis.

Example COG The amount of detectable leakage of ammonium water relative to the amount of seawater used for indirect cooling was measured. The results are shown in Figure 3.

In the figure, 2 indicates the possible range of seawater usage. According to the same figure,
It can be seen that within the possible seawater usage range, leakage of ammonium water as small as 0.05 H can be detected, indicating high detection accuracy.

As explained above, according to the present invention, the cooling pipe in the ammonium water cooler for circulating the ammonium water used for liquid cooling is damaged due to causes such as corrosion. Even if ammonium water leaks into the cooling water, it is possible to detect the leakage of ammonium water into the cooling water at an early stage by measuring the hydrogen sulfide concentration using an underwater cyanide detector and detecting changes in the concentration. As a result, the present invention has the effect of preventing harmful substances such as hydrogen cyanide contained in ammonium water from being discharged into the sea, rivers, etc., and is an extremely useful invention from the standpoint of preventing pollution.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the 9000 cooling process of implementing the ammonium water leak detection method of the present invention, Figure 2 is a graph showing the relationship between the amount of ammonium water mixed into seawater and the detector potential, and Figure 3 The figure is a graph showing the amount of detectable ammonium water leakage versus the amount of seawater used for COG indirect cooling. 8...Anonymous water 14...Cooling pipe 16...Cooling water 19...Underwater cyanide detector (8)

Claims (1)

[Claims] A silver ion electrode is used as a detection electrode in a method for detecting leakage of ammonium water into cooling water due to breakage of a cooling pipe used to directly cool coke oven gas and to indirectly cool Kuan water with cooling water. A method for detecting leakage of ammonium water into cooling water, characterized in that hydrogen sulfide concentration is measured using an underwater cyanide detector using an underwater cyanide detector, and leakage of ammonium water into cooling water is detected from changes in the concentration.