JP2009248063A - Method for recovering detergent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recovering a detergent, by which a detergent can be dehydrated at a high recovery rate without requiring any special complicated apparatus. <P>SOLUTION: The method for distilling and dehydrating a detergent containing water includes mixing the detergent with a halogenic solvent having a boiling point of 30°C or higher and 100°C or lower, distilling the mixture, and then separating the detergent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water-soluble cleaning agent used for cleaning parts, etc. in various industrial fields such as automobiles, machines, precision equipment, electricity, electronics, etc., from a cleaning agent in which water is dissolved along with cleaning of parts, etc. The present invention relates to a method for recovering a cleaning agent that efficiently separates the water.

  Parts, etc. that are handled in various industrial fields such as automobiles, machines, precision equipment, electricity, electronics, etc., use processing oil, wax, grease, flux, etc. in their processing. Many water-containing processing oils and other water-containing products exist, and after processing they are cleaned with water-based cleaning agents, water-based cleaning agents with hydrocarbon or halogen-based cleaning agents, and alcohol-based processing agents. Cleaning with a water-soluble solvent such as a glycol ether type is performed.

  A water-soluble cleaning agent (hereinafter referred to as a cleaning agent) can be removed by dissolving water, has few problems such as rust on parts, etc., and can be regenerated and reused by distillation. It is used not only for removing dirt containing water, but also for removing pure water that adheres after washing with a water-based cleaning agent and rinsing with pure water, but as the cleaning continues, the water concentration gradually increases. Since the cleaning properties and drying properties are deteriorated, the cleaning agent is dehydrated by simple distillation or flushing and used repeatedly in order to maintain the performance (see, for example, Patent Documents 1 and 2).

  However, in the conventional dehydration method using simple distillation or flash, a large amount of the cleaning agent evaporates along with the water and is discarded, so there is a problem that the recovery rate is low in order to maintain the water concentration that can maintain the performance of the cleaning agent. is there.

  In order to increase the recovery rate of the cleaning agent, a dehydrating method of the cleaning agent by multistage distillation or membrane separation is effective, but these have problems that the equipment cost is expensive and the operation is extremely complicated.

JP-A-7-308501 (Claim 1) JP 2006-22167 A (Claim 3)

  The present invention provides a dehydration method capable of separating water at a high recovery rate from a detergent in which water is dissolved without requiring a particularly complicated apparatus.

  Based on such circumstances, the present inventors have made various studies to solve the above-mentioned problems, and as a result, have found a target dehydration method and have completed the present invention.

  That is, according to the present invention, in the method of distilling a water-containing cleaning agent by distillation, the cleaning agent is separated by distillation after mixing the halogenated solvent having a boiling point of 30 ° C. or higher and 100 ° C. or lower with the cleaning agent. The present invention relates to a method for recovering a cleaning agent.

  Hereinafter, the present invention will be described in more detail.

  The recovery method of the present invention is mainly composed of water-soluble glycol ethers, esters, alcohols and the like used for removal of soils containing water such as water-soluble processing oil and water adhering after aqueous cleaning. It can be preferably applied to a cleaning agent having a boiling point of about 130 ° C. or higher.

  Examples of the cleaning agent include diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, diethylene glycol butyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol methyl ether, triethylene glycol dimethyl ether, propylene glycol ethyl ether, propylene glycol n- Propyl ether, propylene glycol t-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, tripropylene glycol methyl ether, 3-methoxy-1-butanol, 3-methyl-3-methoxy-1-butanol, ethyl lactate, Butyl lactate, diethylene Glycol, propylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, butanediol, what was the main agent and tetrahydrofurfuryl alcohol can be exemplified. As long as the performance of dissolving and removing water can be maintained, even a mixture of other components can be applied.

  Specific examples of halogen solvents used in the present invention include chlorine solvents such as methylene chloride, trichloroethylene, dichloroethane, and tetrachloroethylene, bromine solvents such as bromopropane, heptafluorocyclopentane, tetrafluorobutane, and pentafluoro. Butane, hexafluorobutane, heptafluorobutane, octafluorobutane, hexafluoropentane, heptafluoropentane, octafluoropentane, nonafluoropentane, decafluoropentane, heptafluorohexane, octafluorohexane, nonafluorohexane, decafluorohexane, etc. Hydrofluorocarbons, HFC-365mfc, HFC-43-10mee, HFE-347pc-f, HFE-347mcf, HFE-458mec It can be exemplified HFE-449mec-f, HFE-55-10mec-fc, HFE-54-11mec-f, the hydrofluoroethers such as HFE-449mccc.

  In particular, from the viewpoint of safety and environmental protection, heptafluorocyclopentane, HFC-365mfc, HFC-43-10mee, HFE-347pc-f, which has no flash point, no ozone depletion coefficient, and low global warming potential, HFE-449mccc and the like can be preferably used.

  These halogen-based solvents can be used alone or in combination of two or more, and other components can be mixed and used as long as these effects are maintained. Further, it is more preferable to select and use one having a boiling point 70 ° C. or lower depending on the boiling point of the cleaning agent.

  As the halogen solvent used in the present invention, those having a boiling point of 30 ° C. or more and 100 ° C. or less can be suitably used. When a halogen-based solvent having a boiling point of less than 30 ° C. is used, it is not easy to liquefy and recover the halogen-based solvent in the distillation step for separating the cleaning agent and the halogen-based solvent, and the boiling point exceeds 100 ° C. When a halogen-based solvent is used, heating exceeding 100 ° C. is required in the distillation step, and thus the cleaning agent is likely to be thermally deteriorated.

  In the recovery method of the present invention, it is preferable to mix 10% by volume or more of the halogen-based solvent with respect to 100% by volume of the cleaning agent. More preferably, it is 15 volume% or more and 500 volume% or less. If the amount is less than 10% by volume, it is difficult to obtain a dehydrating effect of the cleaning agent. The larger the amount of the halogen-based solvent mixed, the higher the dehydrating effect of the cleaning agent. The effect does not change.

  The halogen-based solvent used in the present invention is highly compatible with a cleaning agent and can be quickly mixed by simply stirring. As a means for mixing the cleaning agent and the halogen-based solvent, a mixing tank is provided and the cleaning agent and the halogen-based solvent are added, the mixing is performed by the flow of each liquid, the stirring tank is provided in the mixing tank, and the mixing is performed. Conventional mixing methods such as a method of mixing these liquids through a line mixer or the like can be used.

  In addition, since the halogen-based solvent used in the present invention has low solubility in water, depending on the mixing ratio with the cleaning agent and the moisture concentration of the cleaning agent, the mixed solution is divided into an aqueous phase mainly containing water, a cleaning agent, and Two phases can be separated into a solvent phase which is a mixture of halogenated solvents. Furthermore, since the specific gravity of the halogen-based solvent used in the present invention exceeds 1, the difference in specific gravity between the aqueous phase and the solvent phase can be increased. The phase can be separated at the bottom and the aqueous phase can be easily removed.

  When the mixed liquid is separated into two phases, as a means for separating and removing the aqueous phase, a static settling tank having a liquid extraction line arranged at the top is provided, and the mixed liquid is separated into an upper phase and a lower phase. A method of extracting from the extraction line, or a method of extracting a lower phase by providing a liquid extraction line at the bottom of the static-setting tank can be employed. If a coalescer is provided in the static settling tank and the mixed liquid is arranged to pass through the coalescer, the separation into the upper and lower phases can be further accelerated. It is also possible to provide a water absorption filter and bring the mixed solution into contact with it to absorb and remove moisture. In addition, it is preferable that the static detention tank also serves as the mixing tank.

  The cleaning agent mixed with the halogen-based solvent and separated into two phases to remove the aqueous phase is then distilled, and the halogen-based solvent and water are separated from the cleaning agent by distillation. The halogen-based solvent used in the present invention has a boiling point that is significantly lower than the boiling point of the cleaning agent, so that it can be distilled at a lower temperature than simply dehydrating the cleaning agent by distillation. Can be separated from the cleaning agent with high efficiency.

  The distillation is composed of a distillation pot that stores and heats the processing liquid, and a cooler that is connected to the distillation pot and condenses and liquefies the vapor of the processing liquid. A conventional apparatus capable of distilling and separating the halogen-based solvent can be used.

  In order to perform distillation more efficiently and safely, for example, a wire mesh, demister, baffle plate, etc. is provided in the distillation kettle or between the kettle and the cooler to prevent the splashes of detergent from entraining in the steam. In addition, a storage tank is provided at the bottom of the distillation kettle via an opening / closing device, and further, for example, a cooling means such as a cooling coil is provided in the storage tank, and the cleaning agent after distillation is extracted from the distillation kettle into the liquid storage tank and cooled. It is preferable to take it out.

  Distilling kettle heating means can be directly heated by installing various heaters in the distilling pot, but heating means such as heater, steam, heat transfer oil etc. are provided outside the distilling pot and indirectly through the distillation kettle. In addition, a method of heating the treatment liquid indirectly, or by providing a steam or heat medium oil circulation line in the distillation kettle and heating the treatment liquid indirectly is desirable because of its high safety.

  As the cooler, for example, a conventional heat exchanger such as a coil type, a shell and tube structure, a double pipe type, or a plate type heat exchanger can be used.

  It is also possible to perform vacuum distillation by providing a vacuum generating means such as a vacuum pump and an ejector to the distiller constituted by these.

  The condensate discharge port of the cooler is connected to the mixing means, and the halogenated solvent liquefied by the cooler can be sent to the mixing means and reused. In this case, since the liquid condensed in the cooler contains water having a solubility higher than that of the halogen solvent, a water separator is provided between the cooler and the mixing means, and the halogen solvent from which water has been separated is reused. It is desirable.

  The recovery method of the present invention can dehydrate the cleaning agent at a high recovery rate without requiring a particularly complicated apparatus, and can make the cleaning agent repeatedly usable.

Examples 1-14
The following cleaning agent dissolved by adding a predetermined amount of pure water to a separating funnel was weighed out, and further, a predetermined amount of the following halogenated solvent was weighed, stirred and mixed. At this time, when water separated into two phases, the separatory funnel was allowed to stand, and the lower phase separated after 10 minutes was extracted. Transfer this mixture (lower phase liquid if separated into two phases) to a round bottom flask and heat in a temperature-controlled oil bath until the halogen solvent concentration in the cleaning agent is 5 wt% or less. Was evaporated. Using the cleaning agent remaining in the round-bottomed flask as a recovery liquid, the weight, moisture concentration, and cleaning agent concentration were measured, and the recovery rate of the cleaning agent was calculated by the formula (1) and evaluated according to the following evaluation criteria.

    Water concentration: measured using a Karl Fischer moisture measuring device (Mitsubishi Chemical).

    Cleaning agent concentration: It measured using gas chromatograph GC-14A (made by Shimadzu Corporation).

Formula (1)
Recovery rate (wt%) = [weight of recovered liquid (g) x concentration of detergent in recovered liquid (wt%)
× (100-water concentration of recovered liquid (wt%)) / detergent treatment amount (g)] × 100
Evaluation criteria of recovery rate ◎: 95 wt% or more, ○: 90 wt% or more and less than 95 wt%,
Δ: 80 wt% or more and less than 90 wt%, ×: less than 80 wt% Type of cleaning agent and solvent:
HC-AD50 (manufactured by Tosoh Corporation)
3-Methyl-3-methoxy-1-butanol (MMB)
Dipropylene glycol monomethyl ether (DPM)
Propylene glycol-n-propyl ether (PNP)
Types of halogenated solvents:
HFE-347pc-f
HFC-365mfc
HFE-449mccc
Comparative Examples 1-3
A cleaning agent dissolved by adding a predetermined amount of water to a round bottom flask was weighed and heated in a temperature-controlled oil bath to evaporate the cleaning agent and water until the cleaning agent had a predetermined moisture concentration. The weight and moisture concentration were measured using the cleaning agent remaining in the round bottom flask as the recovered liquid, and the recovery rate of the cleaning agent was calculated by the formula (2) and evaluated according to the above evaluation criteria.

Formula (2)
Recovery rate (wt%) = [weight of recovered liquid (g) × (100−water concentration of recovered liquid (wt%))
÷ Detergent treatment amount (g)] x 100
These results are shown in Table 1.

本発明による回収方法によれば、単に洗浄剤を蒸留する方法に対して、より低温で、高い回収率で洗浄剤を脱水することが可能である。また、水溶性洗浄剤に対するハロゲン系溶剤の混合比率を調整することによって、高い回収率を保ったまま、洗浄剤中の水分を任意の水分濃度に減少させることができる。

According to the recovery method of the present invention, it is possible to dehydrate the cleaning agent at a lower temperature and at a higher recovery rate than the method of simply distilling the cleaning agent. Further, by adjusting the mixing ratio of the halogen-based solvent with respect to the water-soluble cleaning agent, the moisture in the cleaning agent can be reduced to an arbitrary moisture concentration while maintaining a high recovery rate.

Claims (4)

In the method of distilling a water-containing cleaning agent by distillation, the cleaning agent is separated by distillation after mixing a halogen-based solvent having a boiling point of 30 ° C. or higher and 100 ° C. or lower with the cleaning agent. Agent recovery method. In the method of dehydrating a detergent containing water by distillation, after mixing a halogen-based solvent having a boiling point of 30 ° C. or more and 100 ° C. or less with the detergent, the two-phase separated aqueous phase is removed and the solvent phase is distilled. And then separating the cleaning agent. The halogen-based solvent is a solvent mainly composed of one or more selected from C3-6 hydrofluorocarbons or hydrofluoroethers, and mixed with 10% by volume or more with respect to 100% by volume of the cleaning agent. The method for recovering a cleaning agent according to claim 1 or 2, wherein: A mixing means for mixing the cleaning agent and the halogenated solvent, a separating means for removing the aqueous phase separated into two phases from the mixture, and a halogenated solvent and the cleaning agent from the solvent phase from which the aqueous phase has been removed by distillation. A cleaning agent recovery apparatus comprising a recovery means for separating.