JPS6146517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recycling high-boiling point dirty oil containing polluting components and surfactants, and more particularly, to a method for recycling used oil-impregnated cleaning fiber products containing non-ionic surfactants. When producing recycled oil-impregnated fiber products for cleaning, the oil-impregnated fiber products are cleaned using an oil agent as a cleaning medium, and then the oil-impregnated fiber products after cleaning are deoiled so that 12 to 30% by weight of the oil agent remains based on the weight of the fibers. An alkaline aqueous solution and a lower alcohol or glycol monoether are added and mixed to the high-boiling point dirty oil containing polluting components and surfactants recovered in the cleaning and deoiling step, and the high-boiling point oil in this added mixture is is separated as a substantially refined oil layer, and
The present invention relates to a method for regenerating high boiling point dirty oil, which is characterized by transferring a surfactant to an alcohol or glycol monoether layer and transferring polluting components to an alcohol or glycol monoether layer and/or an aqueous layer.

Used oil-impregnated fiber cleaning materials contain a combination of cationic, nonionic, or amphoteric surfactants as dust adsorbents and nonvolatile mineral oils or synthetic oils, and also contain large amounts of dirt, dust, Other inorganic or organic dirt, mold, bacteria, etc. are attached. Thus, the wastewater discharged during the recycling and cleaning of cleaning materials contains an extremely high concentration of emulsified oil, and also contains pollutants such as COD and SS at a high concentration, making it difficult to treat the wastewater. Wastewater treatment requires many steps such as primary treatment and secondary treatment, and the cost of the treatment is also quite high.

In order to eliminate these drawbacks, after cleaning used dirty cleaning oil-impregnated fiber products using the dust-absorbing oil agent itself, which is used to adsorb dust to the fibers, the amount of the remaining oil agent is removed to an appropriate level. It has already been proposed to perform both the cleaning and oil impregnation processes consistently by adjusting the adjustment within a certain range (Japanese Patent Publication No. 53).
-37471).

As mentioned above, this method is superior in that both the cleaning and oil impregnation steps are performed consistently and does not require wastewater treatment after cleaning, but as the cleaning operation is repeated, it becomes contaminated. A problem arises in that components accumulate in the oil agent and it is difficult to remove these contaminating components. As is clear from the fact that dust-absorbing oils are non-volatile when used in the above-mentioned cleaning products, they have a high boiling point and are difficult to purify by distillation using simple means such as ordinary dry-cleaning solvents. It is. Furthermore, this oil has a high viscosity and is relatively difficult to purify by filtration, and even if it were to be filtrated, it is virtually impossible to sufficiently remove the contaminant components contained therein.

The present inventors believe that when an aqueous alkali solution and lower alcohol or glycol monoether are added to and mixed with such high-boiling point dirty oil and left to stand, the uppermost oil layer consisting of substantially purified high-boiling point oil, alcohol or is separated into a glycol monoether intermediate layer and a lower layer consisting of water, the surfactant is transferred to the intermediate layer, and the pollutant components are transferred to the intermediate layer and/or the water layer, making it possible to regenerate the high boiling point oil. I discovered that.

The high-boiling point oil targeted in the present invention includes mineral oil, synthetic lubricating oil, or a mixture thereof, and any oil suitable as a dust-absorbing oil can be used. These oils can be used under normal conditions (20℃, 1
It is non-volatile (non-drying) at atmospheric pressure) and has a viscosity of 8 to 100 cP, preferably 10 to 90 cP, measured at 100 m. Suitably, the oil has an aniline point of 20 to 80, preferably 40 to 60, an ignition point of at least 130°C, a boiling point of at least 280°C, and a temperature of less than 15 mmHg measured at 70°C. also has low vapor pressure. The mineral oil may consist of paraffinic hydrocarbons, naphthenic hydrocarbons, aromatic hydrocarbons or mixtures thereof, suitable examples of which are liquid paraffin, spindle oil, machine oil, refrigeration oil and others. It is a petroleum-based lubricating oil. Synthetic lubricating oils include polyolefin oil (α-olefin oil), polyglycol oil, polybutene oil,
Examples include alkylbenzene oil, diester oil, polyol ester oil, polyphenyl ether oil, and isoparaffin oil.

In the case of oil-impregnated fiber products for cleaning, in addition to the above-mentioned oil agents, a cationic surfactant and a cationic surfactant may be added to the oil agent for the purpose of imparting dust adsorption properties, or further imparting self-emulsifying and self-exhausting properties. A combination with a nonionic surfactant, or an amphoteric surfactant having a cationic active group such as a quaternary ammonium group or an amino group and an anionic active group such as a carboxylic acid or sulfonic acid group, or the above cation. Amphoteric surfactants containing active groups and nonionic active groups such as polyethylene oxide groups are included.

Furthermore, oil-impregnated fiber products for cleaning contain antioxidants to prevent deterioration of the oil agent, antifungal agents to prevent the growth of mold and bacteria, and antibacterial agents. During the cleaning and deoiling treatments described below, some of it will migrate into the oil agent that is the cleaning medium, but when the regeneration treatment of the present invention is performed, this material will migrate into the alcohol layer or further into the aqueous layer and be separated from the oil agent. You can also do that.

Dirt on used fibers is a complex mixture of the various types of stains mentioned above that adhere to or are adsorbed to the fibers, and can become stuck to the fibers due to long-term use or neglect. There are some.

For this reason, when cleaning oil-impregnated fiber products for cleaning using the oil itself as a cleaning medium, it is necessary to use nonionic surfactants, especially nonyl phenyl or ethylene oxide adducts of higher alcohols, to enhance the cleaning power. Nonionic surfactants, among others
The average added mole of ethylene oxide is 1 to 10 moles. The amount added is preferably in the range of 3 to 20% by weight based on the oil agent as the cleaning medium.

As the washing machine, a commercially available rotary washer may be used, but a washer capable of washing and deoiling (adjusting the amount of oil retained), such as Floatair manufactured by Washex, USA, is preferred. Washing is preferably carried out at room temperature, but in some cases it can also be carried out at a temperature of 60 to 80°C for 30 minutes to 1 hour. The amount of oil left on the fibers varies depending on the type of fiber base material, but is suitably in the range of 12 to 30% by weight, particularly 18 to 23% by weight, based on the weight of the fibers.

After washing, the recovered oil is passed through a wire mesh to separate coarse fibers and garbage, and then, if necessary, is filtered using a supernatant such as acid clay or diatomaceous earth, and then subjected to the recycling treatment of the present invention. Invest.

In the present invention, it is important to add a combination of an aqueous alkaline solution and a lower alcohol or glycol monoether to the above-mentioned dirty oil.
In order to remove the dirt components in dirty oil, it is possible to mix it with water and transfer the dirt into the water layer, but in this case, the oil will emulsify under the influence of the activator, making it impossible to completely separate and regenerate the oil. becomes difficult. As the lower alcohol, monohydric alcohol having 2 to 4 carbon atoms, especially isopropyl alcohol, is preferable in order to transfer surfactants or other additives into the alcohol layer.From the same point of view, as the glycol monoether, ethylene glycol Lower alkyl ethers such as ethylene glycol monobutyl ether are preferred. These alcohols are preferably added in an amount of 30 to 100% by weight based on the dirty oil. As the alkaline aqueous solution, use an aqueous solution containing alkali hydroxide such as sodium hydroxide or potassium hydroxide at a concentration of 2 to 4 moles, and add this aqueous solution in an amount of 50 to 150% by weight based on the dirty oil. This is desirable in order to transfer the surfactant to the alcohol layer and separate the oil agent.

By allowing dirty oil mixed with alcohol or alkaline aqueous solution to stand still, the oil agent will float to the top layer in a purified state, the surfactant will migrate to the alcohol layer, which is the middle layer, and the dirt components will move to the middle layer. It moves to a layered alcohol layer and/or a lowermost aqueous layer. Generally, this separation into layers proceeds within one hour, particularly within 30 minutes. However, it is of course also possible to perform a centrifugation operation to facilitate separation.

The oil agent in the top layer can be recovered by means known per se and used repeatedly for cleaning and oil impregnation treatment of used oil-impregnated textile products, while from the middle layer,
Alcohol can be separated and recovered by distillation and used repeatedly in the regeneration process of the present invention.

The feature of the method of the present invention is that the oil agent is cleaned by letting the dirty oil mixed with alcohol and alkaline aqueous solution stand still, and in particular, the combination of alkaline aqueous solution and alcohol is the optimum condition for cleaning dirty oil. For example, if a neutral inorganic salt such as common salt or sodium sulfate aqueous solution is used instead of an alkaline aqueous solution, a three-layer separation occurs: an oil layer, an alcohol layer, and an alkaline aqueous solution layer, whereas phase separation occurs. It is incomplete and difficult to use as a practical method for cleaning dirty oil. Therefore, it is clear that the method of the present invention is significantly different from the salting-out effect of an aqueous alkaline solution than a mere salting out effect of inorganic salts. In short, the selection of alcohols and alkaline aqueous solutions provides the optimum conditions for refining dirty oil.

The invention is illustrated by the following example.

Example 1 A used oil-impregnated cleaning fiber product (dust control product) was collected after cleaning with industrial paraffin oil, and the cleaning oil filtered through diatomaceous earth was used as a dirty oil sample.

This cleaning oil is mainly made of industrial paraffin.
Nonionic surfactant 7% by weight, antioxidant 0.35
Contains 1.0% by weight of antifungal agent, 0.15% by weight of antibacterial agent, and several % of animal and vegetable oils, wax, grease, fine earth and sand, etc.

After adding 150% by weight of a 2 molar sodium hydroxide solution to this cleaning oil and stirring,
Isopropyl alcohol (IPA) 80% per sample oil
% by weight was added, and after stirring, the mixture was allowed to stand for 20 minutes.

By the above-mentioned operation, this mixture is separated from the upper layer of oil,
It was possible to completely separate the mixture into three layers: IPA in the middle layer and sodium hydroxide solution in the lower layer. Analysis and visual observation confirmed that the dirt components in the cleaning oil migrated to the IPA layer together with the nonionic surfactant. Additionally, other additives such as antioxidants can also be added to IPA.
It was confirmed that there was a transition to a layer. The recovery rate of recycled oil based on dirt and cleaning oil was 95% by volume, and when measuring the absorbance at a wavelength of 600 nm, the original sample (cleaning dirty oil) had an absorbance of 0.7, which decreased to 0.13. It was confirmed that there is.

After separating the reclaimed oil, the IPA layer was separated and subjected to distillation, and could be recovered with a recovery rate of 98%.

Claims (1)

[Claims] 1. A used cleaning oil-impregnated fiber product is cleaned using an oil agent containing a nonionic surfactant as a cleaning medium, and then the oil agent remains in an amount of 12 to 30% by weight based on the weight of the fibers. When producing recycled oil-impregnated fiber products for cleaning by deoiling oil-impregnated fiber products after washing, high-boiling point dirty oil containing pollutant components and surfactants recovered in the washing and deoiling process is used. , an aqueous alkali solution and a lower alcohol or glycol monoether are added and mixed, the high-boiling oil in this addition mixture is separated as a substantially purified oil layer, and a surfactant is added to the alcohol or glycol monoether layer, A method for regenerating high-boiling point dirty oil, which comprises transferring pollutant components to an alcohol or glycol monoether layer and/or an aqueous layer. 2 The alkaline aqueous solution contains 2 to 4 alkali hydroxides.
The method according to claim 1, wherein the method is an aqueous solution containing a molar concentration and is added in an amount of 50 to 150% by weight based on the high boiling point oil. 3. The method according to claims 1 and 2, wherein the lower alcohol or glycol monoether is added in an amount of 30 to 100% by weight based on the high boiling point oil. 4. The method according to claims 1 to 3, wherein the lower alcohol is isopropyl alcohol. 5. The method according to claims 1 to 4, wherein the glycol monoether is a lower alkyl monoether of ethylene glycol.