JPS6336839B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for treating sludge from a dry cleaning machine, and more particularly to a method for treating sludge discharged from a dry cleaning machine, which recovers valuables and makes the sludge pollution-free. Sludge (mainly filter sludge and oil sludge consisting of dust, oil, fibers, etc. entrained from filter sludge and clothing) that accumulates in the storage tank of cleaning solvents (e.g., benzine, carbon tetrachloride, trichlorethylene, tetrachlorethylene, etc.) in dry cleaning machines is Because it contains cleaning solvents, it poses problems such as recovery of valuables and toxicity, making it impossible to dispose of it as is. In other words, in the past, it was customary to periodically stop the equipment, manually scrape out the sludge that accumulated in the cleaned solvent storage tank, and then process it separately. There were problems such as the generation of bad odors and treatment costs, and there was an urgent need to consider measures to treat the sludge. Therefore, the present inventors investigated and tested the properties of the sludge discharged from dry cleaning machines in detail, and as a result of many experiments, they found that after heating the sludge accumulated in the storage tank to a certain temperature level, air was circulated. After completely recovering the cleaning solvent in the sludge, the resulting residue containing oil and surfactant is 5000
Since it emits ~7000Kcal/Kg of heat and burns at around 300℃, it is incinerated into ash to reduce its volume to around 1/5.
The present invention was achieved by discovering that it can be disposed of as harmless ash. That is, the present invention accumulates oily sludge discharged from a washing drum and sludge derived from filter material discharged from a filter in a collection tank,
The accumulated sludge is left for a certain period of time to separate into liquid and solid content, and the separated liquid content is led to an evaporator and heated to separate the solvent and oil contained in the liquid content and remove the solvent. After that, the solids remaining in the recovery tank are heated and blown with air to dissipate and recover the solvent contained in the solids, and the residue is burned in the recovery tank. The present invention relates to a method for treating sludge in a dry cleaning machine. The present invention will be specifically explained based on the flow sheet of FIG. 1, taking as an example the case where percrene (tetrachlorethylene) is used as a cleaning solvent. Put clothes, etc. into washing tub W, then into tank T ₂
Clean cleaning solvent Perclean 1 and/or detergent S (cationic, anionic, nonionic surfactants such as ABS, DBS, etc.) are supplied via valve _{V 1 , pump P 1} , valve V ₃ , and line L ₁ Then stir and wash. The cleaning solvent that becomes dirty as the washing progresses is removed by the pump _P2 .
It is sent to filter F via V ₄ to remove solid matter, fibers, etc., and at the same time as washing is completed, the washing tub W is deodorized and, prior to drying, it is extracted to tank T ₁ via valve V ₅ .
After leaving this contaminated cleaning solvent for a certain period of time, tank T ₁
The sludge accumulated at the bottom has a composition as shown in Table 1.

[Table] The contaminated cleaning solvent separated from the sludge and stored in the tank T ₁ is sent to the evaporator E via the valve V ₆ , the pump P ₁ and the valve V ₂ . Here, the cleaning solvent is heated by heater H ₂ to vaporize it, and is led to decanter D via valve V ₇ and condenser C, where the coexisting moisture is discharged from line 10, and the cleaning solvent is transferred from line 11 to line 1. It is then returned to Tank T ₂ for reuse. Liquid substances such as oil and surfactants remaining at the bottom of the evaporator E are drained from valve V ₈ to oil tank T ₃ after several cycles of operation or when the amount exceeds a certain level, or are drained from tank T through line 5. Returned to ₁ . The oily sludge in the tank _T1 after the liquid content has been separated in this way is heated by the heater H1 at the bottom of _T1 , and then _the heated air sent from the air blower B through the air heater _H3 is heated to the _T1 sludge. The perclean is vaporized by air dissipation and recovered from line 2, valve V ₉ , condenser C, and decanter D as described above. The cleaning solvent recovered by the evaporation and air dissipation had the composition shown in Table 2, and emulsion formation was observed due to the presence of moisture. It can be seen from the table that perclene is recovered with high purity.

[Table] On the other hand, only the non-condensed air is returned to the air blower B through line 3 and circulated, and the perclean is completely recovered. In order to determine the optimum temperature for heating the sludge, the heating temperature was changed to allow air to diffuse, and the resulting drying loss of the sludge was measured. As a result, at room temperature, the weight loss is only about 20% even after 80 minutes, and drying is slow, but when heated to about 120℃, the weight loss is only about 20%.
It was confirmed that approximately 33% of the low-boiling components were volatilized in minutes, and large heat generation (ignition) occurred at around 300℃, and when combined with the former, the weight was reduced by approximately 70% and 30% remained as ash. If the processing time is sufficient for heating the sludge, only one of the heater H ₁ and the air heater H ₃ may be used. After the liquid components have been separated in this way, sludge with the properties and composition shown in Table 3 remains in tank _T1 . As can be seen from this table, most of the percrene can be removed by heating to about 120°C and dissipating the air.

[Table] Dispersion conditions: Air flow rate 0.5/min, dissipation for 2 hours This sludge is ignited by the igniter P, and at the same time it is exhausted from the exhaust gas damper D _E to burn and ash the sludge. The ash thus obtained can be easily disposed of since only the solid content in the sludge remains, reducing the volume to about 1/5 of the initial volume and rendering it harmless as shown in the analysis results in Table 4. will be processed as necessary.

【table】

【table】

[Table] The exhaust gas composition during combustion is CO ₂ 16%, H ₂ O 10%,
The remaining N ₂ and HCl were approximately 0.02%.

[Brief explanation of the drawing]

The accompanying drawing is a flow sheet illustrating one embodiment of the invention.

Claims (1)

[Claims] 1. The oily sludge discharged from the washing drum and the sludge derived from the filter material discharged from the filter are accumulated in a collection tank, and the accumulated sludge is left for a certain period of time to separate into liquid and solid components. The separated liquid is guided to an evaporator and heated, the solvent and oil contained in the liquid are separated and the solvent is recovered, and then the solid remaining in the recovery tank is heated and blown with air. A method for treating sludge in a dry cleaning machine, characterized in that the solvent contained in the solid content is diffused and recovered, and the residue is burned in the recovery tank.