JPH07132195A - Method for decomposing away dry cleaning solvent by utilizing ultrasonic wave - Google Patents

Abstract

PURPOSE:To obviate the generation of pollution by decomposing the chlorine solvent used for dry cleaning. CONSTITUTION:An aq. soln. contg. tetrachloroethylene, 1. 1.1-trichloroethane and fluorocarbon-113 obtd. by azeotropically evaporating the solvent contg. water after dry cleaning by a distillator, cooling the vapor thereof by a condenser and separating the vapor by a separator is irradiated with high-output ultrasonic waves of about 20 to 600kHz to vibrate the aq. soln.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decomposing and removing a dry cleaning solvent using ultrasonic waves.

[0002]

2. Description of the Related Art Conventionally, non-flammable solvents such as trichloroethylene, tetrachloroethylene, 1.1.1-trichloroethane, CFC-113 and other chlorine-based solvents have been used for dry cleaning, and petroleum-based solvents have also been used.
These solvents are azeotropically vaporized with water and the like contained in the object to be washed by a distiller after dry cleaning, cooled by a condenser, and separated by a specific gravity difference by a separator.

[0003]

However, in the water discharged after the separation as described above, 50 ppm to 100 ppm is contained.
Since some solvents are included, pollution problems occur. Surfactants and alcohols are also included in the detergent for dry cleaning, and water is azeotropically distilled with water by the distiller, a mixed emulsion of water, a surfactant and a solvent, tetrachloroethylene, 1.1.1- It is separated into three layers such as trichloroethane and freon, petroleum solvent,
It may be separated into a mixed emulsion of water, a surfactant and a solvent, and three layers of water.

Therefore, when the mixed emulsion is partially drained after draining after the separation of these three layers, 1
Solvents of about 20 ppm to 200 ppm are mixed and discharged into the sewer. Furthermore, when a bumping phenomenon occurs due to a valve operation error, rapid heating, poor cleaning, etc., when using a distiller, 1000 ppm to 1200 ppm
Solvents above ppm will be mixed and contained in the wastewater. As a result, groundwater pollution occurs from the infiltration of wastewater,
Eventually, there were problems that could cause river pollution.

Various methods have been studied in order to suppress the waste water containing the solvent as described above to 0.01 ppm as announced by the Environmental Agency. For example, there is a method of passing through an activated carbon layer,
In this method, adsorption by activated carbon becomes saturated immediately, and disposal of activated carbon containing a solvent becomes a problem. Further, in the centrifugal separation method utilizing the difference in specific gravity between water and solvent, 0.01
It is difficult to reduce the amount to ppm or less, and there is a drawback that the effect is not recognized particularly in the separation of the solvent in the wastewater due to the emulsion layer or the bumping phenomenon.

Further, the aeration method, in which air is blown in and diffused into the atmosphere, cannot clear the value of 34 ppb in the environmental guideline, resulting in a problem that a solvent odor or a fatty acid decomposition odor is generated. . Also, as a boiling method, there is also a method of sending steam, heating, vaporizing the solvent together with water vapor, and releasing it to the atmosphere, but it requires a steam boiler, watering of the chlorine-based solvent, thermal decomposition occurs, and a kettle or There are problems such as corrosion of exhaust pipes and diffusion of malodors.

An object of the present invention is to provide a method for decomposing and removing a solvent by ultrasonic waves, unlike the above-mentioned various methods.

[0008]

In order to achieve the above object, the present invention is obtained by azeotropically vaporizing a solvent containing water after dry cleaning with a distiller, cooling with a condenser, and separating with a separator. For an aqueous solution containing a chlorine-based solvent such as tetrachloroethylene, perchloroethylene, trichloroethylene, 1.1.1-trichloroethane, CFC-113,
A method for decomposing and removing a dry cleaning solvent using ultrasonic waves, which decomposes and removes by irradiating and vibrating a high-power ultrasonic wave.

[0009]

[Function] After the dry cleaning, the solvent containing water is azeotropically vaporized by a distiller, cooled by a condenser, separated by a separator, and then tetrachloroethylene, trichlorethylene, 1.1.1-trichloroethane and freon contained in the aqueous solution. It was found that by irradiating an organic chlorine compound such as -113 with ultrasonic waves, a cavitation bubble is generated, and when this bubble collapses, it becomes a high temperature and high pressure state and decomposes into hydrochloric acid, carbon dioxide gas, etc. .

[0010]

[Examples] The following table shows experimental values obtained by decomposing tetrachloroethylene-containing water by ultrasonic irradiation. Water 20 liters Tetrachlorethylene 20cc (concentration 1125pp
m) Soap for the same solvent 2 cc The above mixed aqueous solution is ultrasonic 27 KHz, output 250w 1
The pH value was measured after irradiation for 50 minutes and vibration.

The initial pH value of 6.37 was 60.
It was 3.96 after minutes and 3.74 after 120 minutes, which suggests that the concentration of chloride ions increased and the pH value decreased with the passage of reaction time, resulting in the generation of hydrogen chloride. To be

[0012]

[Table 1]

As the organic chlorine compound, tetrachloroethylene, trichloroethylene, 1.1.1-trichloroethane, etc. were used, and a similar experiment was conducted at a frequency of 200 KHz and an output of 200 w. ,
Decomposition of 53.7% and 71.5% with 1.1.1-trichloroethane was obtained.

As a high output, 20 to 600 KHz
Some of them are suitable for decomposing chlorine solvents.

[0015]

EFFECTS OF THE INVENTION The chlorine-based solvent used for dry cleaning as in the present invention can be decomposed into hydrochloric acid, carbon dioxide gas, etc. by irradiation with ultrasonic waves, and no pollution problem occurs even when it is contained in waste water. It became so.

Claims (1)

[Claims] 1. Tetrachloroethylene obtained by azeotropically evaporating a solvent containing water after dry cleaning with a distiller, cooling with a condenser, and separating with a separator,
Ultrasonic waves characterized by being decomposed and removed by irradiating and vibrating a high-power ultrasonic wave to an aqueous solution containing a chlorine-based solvent such as perchlorethylene, trichloroethylene, 1.1.1-trichloroethane, and Freon-113. Decomposition and removal method of dry cleaning solvent used.