JPS63232898A - Method and device for treating sludge containing organochlorine solvent - Google Patents

Abstract

PURPOSE:To efficiently recover an organochlorine solvent in a short time by heating and agitating the sludge contg. the organochlorine solvent in an extractor, introducing the generated organochlorine solvent vapor into a cooler along with the steam introduced into the extractor and condensing the vapor. CONSTITUTION:The sludge contg. an organochlorine solvent such as perchloroethylene is heated and agitated in the extractor 2, the generated organochlorine solvent vapor is sent to the cooler 10 along with the steam introduced into the extractor 2, and the vapor is condensed. As a result, the organochlorine solvent is efficiently recovered in a short time, and can be reutilized. The sludge freed from the organochlorine solvent can be safely used for land reclamation, and the environmental pollution such as ground water pollution and air pollution can be obviated.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is directed to the treatment of sludge generated during the regeneration of organic chlorine solvents, which is generated when separating and recovering solvents from washing water of transport equipment such as tankers and tank trucks. The present invention relates to a sludge treatment method and apparatus for recovering organic chlorine solvents from the sludge generated, and further from the sludge generated from storage containers and the like.

[Prior art]

Conventionally, sludge containing organic chlorine solvents has been incinerated as industrial waste and disposed of in controlled landfills, but this has disadvantages such as severe corrosion in the incinerator and air pollution.

For example, perchlorethylene, which is used as a solvent in dry cleaning, is contained in cleaning discharge sludge in an amount of about 40 to 50% by weight.

Conventionally, this sludge has been disposed of as industrial waste in a controlled landfill after incineration, but recently, groundwater contamination by perchlorethylene and its carcinogenicity have become a problem.
Collecting and safely disposing of cleaning discharge sludge is rapidly becoming a problem.

As a method to recover perchlorethylene in sludge,
A distillation method is known, and FIG. 2 is a schematic diagram of a conventional apparatus for distilling perchlorethylene from sludge containing perchlorethylene. Sludge containing perchlorethylene is put into a sludge heating tank 21 and heated. Perchlorethylene vapor generated by heating in the vessel 22 enters a cooling tower 23, is cooled in a cooling pipe 24, becomes liquid, and is taken out from a discharge pipe 25.

In the conventional distillation method as described above, after evaporation reaches a certain point, the inside reaches the boiling point of perchlorethylene, that is, 1
There was a drawback that the temperature did not rise to 21.2°C and perchlorethylene remained inside the sludge.

[Purpose of the invention]

The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and it is possible to recover almost the entire amount of organic chlorine solvent from sludge,
The purpose is to enable reuse and prevent pollution such as groundwater pollution and air pollution due to waste.

[Structure of the invention]

In order to achieve the above object, the present invention uses organic chlorine solvents such as trichlorethylene, methylene chloride, 1-1-
Sludge containing 11-lichloroethane, perchlorethylene, etc. is stirred while being heated above the boiling point of the organic chlorine solvent, and the sludge existing in liquid form in the sludge is i.
[I <By pulverizing, the sludge is made into a state in which the organic chlorine solvent can be easily separated. Most of the organic chlorine solvent vapor generated by heating and stirring is then recovered. Almost all of the organic chlorine solvent vapor remaining in the space inside the sealed container and the space within the sludge body can be recovered and reused by supplying water vapor into the sealed container and discharging it to replace the organic chlorine solvent vapor. made possible.

〔Example〕

Embodiments to which the method and apparatus of the present invention are applied will be described below with reference to the drawings. FIG. 1 is a schematic diagram of an apparatus for treating perchlorethylene with sludge in an embodiment of the present invention.

This device is divided into an extractor 2, which is a double tank consisting of an inner cylinder 2A and an outer cylinder 2B, and a cooler 10. Perchlorethylene is produced by a stirrer 9 installed in the inner cylinder 2A of the extractor 2. While stirring the contained sludge, the temperature is raised to the boiling point of perchlorethylene by heating with water vapor S from the outside surface to produce perchlorethylene vapor, and the perchlorethylene vapor existing in the sludge space and the container space is replaced with water vapor S. ′
The perchlorethylene vapor is blown into the cooler 10.
This system collects perchlorethylene and treats the sludge.

Next, to explain the procedure for recovering perchlorethylene from sludge containing perchlorethylene using the recovery device shown in Fig. 1, first, the stop valve 6 for steam S is opened, and the steam S is pumped at a pressure of about 4 kg/cnl. It is supplied between the inner cylinder 2A and the outer cylinder 2B and heated.

Next, open the lid 1 of the extractor 2, put the sludge containing perchlorethylene into the inner cylinder 2A of the double tank of the extractor 2, and
Close and seal.

Next, the displacement steam supply valve 16 is opened to blow displacement steam into the inner cylinder 2A. In the inner cylinder 2A, stirring blades 9 are operated by operating a motor 8 equipped with a speed reduction device 7.
While stirring the sludge, it is heated from the surroundings to generate perchlorethylene vapor at about 121 degrees, which is sent to the cooler 10 together with displacement steam.

The cooler 10 is water-cooled with cooling water Wc, and the stop valve 1
1, and the water and perchlorethylene condensed and liquefied in the cooler IO are collected in a collection container.

Note that the water vapor S supplied between the inner cylinder 2A and the outer cylinder 2B passes through the steam trap 15, becomes a drain D, and is discharged.

In addition, the sludge Md containing perchlorethylene introduced into the double-tank extractor 2 through the lid 1 is treated and then discharged as treated sludge Mc by the stirring blades 9 by removing the lid 19. The sludge is then disposed of in a controlled landfill as inorganic sludge from which perchlorethylene has been extracted.

Therefore, as an example of actual implementation, an example in which perchloroethylene-containing sludge was treated will be described next.

a. Size of extraction container: Internal volume: approx. 25Ab, Stirring device: Rotation speed: 17.8R/M Electric motor: 100V x 0.
2 KW C9 sludge input amount: approx. 20A (20kg) d, properties of input sludge (park content) 15.4% (weight ratio) e, heating temperature 149"C f, heating steam supply amount (3.7kg/cn ( G) 5kg
/Hr g, displacement steam ・ (atmospheric pressure) 0.2 kg/Hr h, cooling water (15°C) 50A/Hr 1, treatment time No amendment requiredj, perchlorethylene content of treated sludge 11■/
kg elution test concentration 0.036 .mu./l As can be seen from this data, it can be seen that in the perchlorethylene-containing sludge treated by the method of the present invention, only an extremely small amount of residual perchlorethylene of 11 ppm remains.

However, in the case of conventional simple heating and stirring drying, it is impossible to reduce the concentration to 1.000 ppm or less because the organic chlorine solvent remaining in the space inside the processing container and the space within the sludge body condenses and re-contaminates the sludge. The reality is that.

When treating sludge containing a solvent with a low boiling point, such as trichloroethane, trichlorethylene, or methylene chloride, with this apparatus, the treatment temperature is controlled by limiting the amount of heated steam supplied.

〔Effect of the invention〕

As explained above, in the sludge treatment method of the present invention, all the sludge is evenly stirred by installing a stirring blade in the heated extractor, and the generated organic chlorine solvent vapor is replaced with water vapor. Therefore, most of the organic chlorine solvents in the sludge can be extracted, and the treated sludge is buried in the landfill as inorganic sludge from which the organic chlorine solvents have been extracted, making safer landfilling possible. Since there is no need for incineration, no toxic gas is emitted during incineration, which has great effects such as preventing air pollution and other pollution.

In addition, since the sludge containing organochlorine solvents is directly heated while stirring and displacement steam is blown into the sludge, the organochlorine solvents can be efficiently recovered and reused in a short period of time, making the sludge more reliable. It is economical as well as making it harmless.

Furthermore, in the present invention, water vapor is introduced into the extractor because
This has the effect of discharging organochlorine solvent vapor from inside the extractor to the outside, and by diluting the organochlorine solvent vapor, it prevents corrosion of equipment after the extractor due to organochlorine solvents. This is because, after the solvent vapor is completely discharged, the adhering portion of the organic chlorine solvent can be cleanly removed by the water vapor, and even if the water vapor remains in the extractor, it is harmless.

[Brief explanation of the drawing]

FIG. 1 is a schematic system diagram of an apparatus for treating sludge containing organochlorine solvents in an embodiment of the present invention, and FIG. 2 shows a conventional apparatus for distilling organochlorine solvents from sludge containing organochlorine solvents. FIG. 2...Extractor, 9...Agitator, 10...Cooler,
S... water vapor, S'... displacement water vapor.

Claims (1)

[Claims] 1. Sludge containing an organic chlorine solvent is heated and stirred in an extractor, and the generated organic chlorine solvent vapor is sent to a cooler together with the water vapor introduced into the extractor and condensed. A method for treating sludge containing organic chlorine solvents that recovers chlorine solvents. 2. An extractor that heats and stirs sludge containing an organic chlorine solvent, a steam supply device that supplies water vapor into the extractor, and a cooler that condenses the organic chlorine solvent vapor and water vapor. Treatment equipment for the sludge it contains.