JPS58177193A - Removal of hydrazine from waste liquid - Google Patents

Abstract

PURPOSE:To easily and efficiently remove hydrazine from waste liquid within a short time, by bringing hydrazine-contg. waste liquid into contact with active carbon to remove hydrazine in the waste liquid by adsorption with the active carbon. CONSTITUTION:Waste water, e.g. a washing liquid or a preserving liquid when a tank is full, containing hydrazine is gathered through a line 2 in a tank 1 for reserving liquid waste. The waste water in the storage tank 1 for waste liquid is sent through a line 4 and a valve 5 into a treatig tank 6 for waste liquid by a pump 3. After a chemical agent is added in the treating tank 6, the waste water is treated below a regulated value and then drained through a line 7. In this method, a line for circulating waste liquid from a liquid-supply line 4 through a valve 8 and a line 9 into a column 10 packed with active carbon and then introducing it through a line 11 into the tank 6 for treating waste liquid is further provided to remove hydrazine in the waste liquid by adsorption in the column 10 packed with active carbon.

Description

[Detailed description of the invention] This article relates to a method of adsorption removal using activated carbon.

In thermal power generation platforms. Water containing hydrazine at a much higher concentration than during normal operation is used for the rinsing solution during Cree/Anop operation and for the full-water storage solution during rest periods to prevent corrosion. This hydrane-containing water is discharged as waste liquid before the plant enters steady operation. Since hydrazino in such waste liquid is a COD loading component, it is necessary to treat the waste liquid to reduce the 01) to within the regulated value when discharging it.

Conventional. As a method for treating hydrazine in such waste liquid, the hypochlorous acid nodal method is used. That is, this is a method in which a sodium hypochlorite solution is added to the hydrazine/waste solution in an amount equivalent to the hydrazine/hydrazine, and the COD reduction is determined while air-raying/y/o/, and the pH is adjusted with hydrochloric acid before being discharged. However, with this method, it takes a considerable amount of time to reduce COD to the regulation value after adding an equivalent amount of sodium hypochlorite solution to hydrazine.

The object of the present invention is to eliminate the above-mentioned drawbacks.

In a method for removing hydrazi/ from a waste liquid containing hydrazi, the waste liquid is adhered to activated carbon, and the
Provided is a method for removing hydrazide from a waste liquid, which is characterized in that hydrazide is removed by adsorption on activated carbon.

The present inventors have conducted research experiments in which dissolved oxygen in water is adsorbed and removed using activated carbon.

It has been found that this dissolved oxygen can be decomposed and removed by a combination of hydrazi and activated carbon.

At this research and experimental stage, we obtained the result that even hydrazide/alone was adsorbed onto activated carbon in a short period of time. The inventors of the present invention have focused on this result and have arrived at the present invention.

Next, an embodiment of the method of the present invention will be explained based on the drawings.

This will be explained according to the flow sheet shown in FIG.

In FIG. 1, 1 is a waste liquid storage tank that receives washing liquid and full-water storage liquid, and is collected from Lie/2.

Normally, this waste liquid is pumped to line 4゜pulp 6 by pump 3.
The liquid is sent to the waste liquid treatment tank 6 through the waste liquid treatment tank 6, where it is treated to below the regulation value after being charged with chemicals.

In the present invention, valve 8. Life]
1 is installed to lead the waste liquid to a waste liquid treatment tank 6, and the hydrazide 7 in the waste liquid is adsorbed and removed by an activated carbon packed column 10.

FIG. 2 shows an experimental example in which a hydrazine removal test was carried out using the column continuous water flow method according to the method of the present invention. below,
This will be explained according to FIG.

Table 1 shows the relationship between the packing density and particle size of the activated carbon used in the experiment.

In FIG. 2, treated water 21 containing hydrazino is prepared in a treated water tank 20, and is continuously passed through a line 221φ to a column 24 by a pump 2'3.

Column 24 contains 500 ml of activated carbon 25 shown in Table 1.
Hidden Schiff in treated water 21 is removed from column 2.
After contacting with activated carbon 25 in 4, the treated water coming out from line 26 was subjected to Sanoprinog, and the remaining hydrazine concentration was determined by iodine titration.

analyzed.

The results of the removal test in the above column continuous water flow test are shown in FIG. In FIG. 3, curve 7 A is the result of a removal test conducted under the condition of 5V=20 using fresh activated carbon and adjusting the hydrazine concentration in the water to be treated to 200 ppm. Also, curve 1 is B.

Activated carbon after testing under the conditions of curve A.

These are the results of a removal test conducted under the above conditions after the activated carbon 25 was regenerated by supplying hot water, steam 27, etc. to the column 24 via the regeneration piping 28 using a generally known method.

The results shown in FIG. 3 show that 10 tons of waste liquid can be treated for 500 tons of activated carbon. 9 For example, if 1 ton of activated carbon is used, waste liquid containing hydrazine (hydrazine/concentration 2
00 ppm) at a rate of 42 tons/process. It can be seen that the adsorption capacity of the activated carbon after one-day regeneration deteriorates by about 5 to 7%, but it recovers to the point where it has the same adsorption capacity as new activated carbon.

As described above, according to the present invention, it is possible to treat 4.2 tons of waste liquid containing about 200 ppm of hydrazino per ton of activated carbon, and the adsorption capacity after regeneration is higher than that of fresh activated carbon. Since the amount decreases by only 5 to 7 inches, it can be used repeatedly.

These results show that the use of activated carbon is an effective method for removing hydrazine from waste liquid.

Note that the present invention applies to 9, for example, the Cree-772 of the Tue J power generation platform.
It can be applied to the case of removing hydrazino from the 1-hour washing liquid, the full-water storage liquid during rest, or the highly concentrated hydrazi-containing waste liquid used as a corrosion protection measure for diesel engine cooling water, shaft cooling water, etc.

[Brief explanation of the drawing]

FIG. 1 is a flow route showing an embodiment of the present invention. Second
1 is a flow route showing an experimental apparatus for carrying out the present invention, and FIG. 3 is a diagram showing experimental data obtained by conducting a test using the experimental apparatus shown in FIG. 2. l... Waste liquid storage tank, 2... Waste liquid injection line/, 6... Waste liquid treatment tank, 7... Treated liquid discharge line, 10... Activated carbon packed tower, 20... Water tank to be treated, 21 ...Water to be treated. 24... Column, 25... Activated carbon, 27... Hot water for regeneration. Steam, 28... Piping for regeneration. 1 Figure 7 2 Fang 27 Procedural amendment (J9:) December 1987 72EI Patent Office Case presentation by Mr. Kazuo Wakasugi 1981 Patent Application No. 59105
Title of invention Name of method for removing hydrazino in waste liquid Relationship with Kushi 4Ll Patent applicant address Tokyo, T-dai 111 [Zu Marunouchi = J] 1
No. 5 113 Name (620) Representative of Mitsubishi Heavy Industries, Ltd. Address Same as above (1) Change "Waste liquid will be collected from line 2" on page 3/line 14 of the specification [waste liquid will be collected from line 2.1 m'J It will be a disaster. ” he corrected. (2) Replace “42” in the 19th line of page 5 with [, l
12. Correct it with J. (3) ``142'' in the 7th line of the 6th page of the same page as ``42''
I am corrected.

Claims (1)

[Claims] A method for removing hydrazine from a waste liquid containing hydrazine, the method comprising adhering the waste liquid to activated carbon, and removing hydrazine in the waste liquid by adsorbing it to the activated carbon.