JP2006198600A - Method and apparatus for oil-water separation and washing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily purifying various kinds of waste liquids, waste oils, or waste water at low initial cost and running cost in a narrow installation space, for recycling and making valuable components repeatedly usable, and for decreasing industrial wastes to the minimum. <P>SOLUTION: After inorganic substance finely divided particles are added to and stirred with a mixture containing an oily liquid, a water-based liquid, and an oily substance, the mixture is kept still to shift the inorganic substance finely divided particles and the oily substance to the water-based liquid phase. Based on two-layer separation of the oily liquid and the water-based liquid, the oily liquid is made reusable by carrying out centrifugation, filtration, or liquid separation. The water-based liquid is discharged or waste water treatment load is lowered. Accordingly, the amount of the industrial waste discharge is considerably decreased. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an oil-water separation method, and relates to a method for treating various waste liquids, waste oil, and waste water.

  In various waste liquids, waste oils, and wastewaters, oily liquids, aqueous liquids, and oily substances and solid suspended substances as contaminants are generally mixed. In order to separate and purify these components and to recycle and recycle useful components, and to drain water into general sewers and rivers, it is necessary to go through expensive and complex waste liquid treatment equipment and processes. In particular, there is a large problem in printing cleaning waste liquid, coating waste liquid, various cleaning process waste liquid, various purification process waste liquid, etc., which are mixed with a lot of solvents and water. In small and medium-sized enterprises that are difficult to introduce expensive waste liquid treatment equipment that requires a large area, it is usual to request waste disposal companies to treat them as industrial waste. Is a big one. In addition, the loss is enormous considering the scale of the global environment, and a technology that can be effectively recycled is required.

Conventionally, there are various techniques for removing contaminants by separating oil and water. For example, there is an oil / water separation filter in which ultrafine fibers are made into a nonwoven fabric. However, the properties of the target liquid are limited, and it is not appropriate when viscous pollutants or solid suspended substances that cause clogging are mixed. Further, in distillation purification, water and oily substances often azeotrope, and both initial cost and running cost increase. The use of flocculants such as inorganic salts and polymers needs to be optimized for each target waste liquid, and may generate new waste that must be treated such as flocculants and chemicals in sludge and treated water. Many. There are many examples of using a flocculant for wastewater treatment, but it has not been used for oil-water separation cleaning recovery of waste oil or waste liquid containing a large amount of oily substances.
Japanese Patent Laid-Open No. 10-309403

  The present invention relates to a method for treating various waste liquids, waste oils, and wastewaters, is simple and versatile, has a low initial cost and a low running cost, has a small installation area, can circulate useful components, and discharge industrial waste. And to provide a method and apparatus for purifying waste water.

  In the process of examining the treatment of printing cleaning waste liquid, the present inventor used inorganic substance fine particles subjected to lipophilic surface treatment in a system in which a cleaning agent mainly composed of aromatic hydrocarbons and waste ink and fountain solution are mixed. It was found that when added, stirred and allowed to stand, it was separated into two layers of a clear oily liquid and an aqueous liquid containing waste ink, and the present invention was completed.

  That is, according to the present invention, inorganic fine particles are added to an oily liquid, an aqueous liquid, and an oily substance, and the mixture is stirred and mixed. An oil-water separation and cleaning method characterized by separating an oily liquid and an aqueous liquid into two layers, and an oil-water separation and cleaning device using the method.

  In the present invention, the oily liquid is a liquid mainly composed of an organic substance that separates layers from water, and refers to various solvents, cleaning agents, lubricants, animal and vegetable oils, mineral oils, monomers, and the like. For example, toluene, xylene, ethylbenzene, hexane, heptane, butane, cyclohexane, decalin, tetralin, turpentine oil, kerosene, medium and high boiling petroleum solvent, liquid paraffin, 2-ethylbutanol, octanol, cyclohexanol, diethyl ether, diisopropyl ether, There are methyl isobutyl ketone, diisopropyl ketone, diisobutyl ketone, ethyl acetate, butyl acetate, and the like, and mixtures thereof are also possible. In the present invention, the aqueous liquid is a liquid mainly composed of water that is separated into layers, and refers to an aqueous solution containing water, an organic substance or an inorganic substance soluble in water. In the present invention, oily substances mixed with oily liquids and aqueous liquids include printing inks, paints, contaminants discharged in various cleaning processes, additives, plasticizers, lubricants, adhesives, low molecular weight resins, Cured resins, liquid rubber, etc. are included. These oily substances may include inorganic pigments and fillers. These oily substances are preferably more viscous than the oily liquid to be washed and refined. In addition, various inorganic substances, organic substances, solid fine particles or solid suspended substances of microorganisms may be mixed in the liquid as foreign matters or dirt.

In the present invention, inorganic fine particles refer to inorganic powders that are insoluble in natural or synthetic water. For example, colloidal calcium carbonate (also called precipitated calcium carbonate), light calcium carbonate, heavy calcium carbonate, porous calcium carbonate, calcium sulfate, aluminum hydroxide, magnesium hydroxide, silica, magnesium silicate, aluminum silicate, kaolin, Talc and other clay minerals are possible, and inorganic powders used as fillers in synthetic rubber and synthetic resin are suitable in terms of safety, versatility, price, etc., and there is no secondary pollution of waste desirable. The average particle size of the inorganic fine particles of the present invention is usually preferably 10 microns or less, and particularly preferably 3 microns or less. For example, light calcium carbonate having an average particle diameter of about 1 micron and heavy calcium carbonate having an average particle diameter of 2 microns and coated with calcium stearate are preferable. In particular, inorganic fine particles having an average particle size of 0.1 microns or less are also preferable. For example, colloidal calcium carbonate having an average particle size of about 0.08 microns is suitable. The lower limit of the average particle diameter is not particularly specified, and can be selected in consideration of ease of handling of the powder. In addition to the average particle diameter, it is possible to select based on a specific surface area or a large oil absorption amount. Porous calcium carbonate having a large oil absorption and an average particle diameter in the range of 1 to 10 microns is particularly suitable.
Moreover, it is preferable that the surface of the inorganic fine particles is subjected to lipophilic treatment. The lipophilic surface treatment can be obtained by coating the surface of the inorganic substance fine particles with a compound containing a lipophilic group and a polar group such as stearic acid or calcium stearate. Further, it can be obtained by coating the surface of inorganic fine particles with a high molecular weight surfactant or an organic polymer having a polar group. It can also be obtained by blowing carbon dioxide into an aqueous solution of slaked lime in the presence of a compound containing a lipophilic group and a polar group, such as colloidal calcium carbonate and light calcium carbonate, to produce calcium carbonate crystals.
The selection of inorganic fine particles can be selected as appropriate depending on the properties of various waste liquids, waste oil, and wastewater to be purified, but the inorganic fine particles agglomerate oily substances that float and diffuse in the liquid, resulting in solid suspended substances. Selection is easy if we assume a mechanism that sinks by increasing its own weight while taking in water. However, if the inorganic substance fine particles are too lipophilic, the inorganic substance fine particles may aggregate oily substances that float and diffuse in the liquid and concentrate in the oily liquid layer without sinking while taking in solid suspended solids. Occur. In this case, it is suitable for purification of an aqueous liquid.

In the present invention, the oil-water separation and cleaning method is a method of adding inorganic fine particles to a state where an oily liquid, an aqueous liquid, and an oily substance are mixed, stirring and mixing, and then allowing to stand, whereby the inorganic fine particles and the oily This is accomplished by agglomerating and moving the substance into the aqueous liquid phase and separating the oily liquid and the aqueous liquid into two layers. The amount of inorganic fine particles added is appropriately determined according to the amount of oily liquid, aqueous liquid and oily material, and the strength of stirring and mixing, but is preferably in the range of 1/10 to 100 times the weight ratio of the oily material. A weight ratio in the range of / 2 to 10 times is more preferable. Moreover, 0.1-10 weight part of inorganic substance microparticles | fine-particles are preferable with respect to 100 weight part of liquid total in which an oily liquid, an aqueous liquid, and an oily substance are mixed, and 1-5 weight part is still more preferable.
For stirring and mixing, a normal stirring and mixing tank can be used, and the entire container can be shaken. What is necessary is that the oily liquid, the aqueous liquid, the oily substance, and the inorganic substance fine particles are uniformly mixed, and no dead angle that is not mixed is created in the container. Moreover, vigorous stirring and strong shaking are desirable so that the inorganic substance fine particles can aggregate all of the oily substance. The time to stand after stirring and mixing is necessary until the oily liquid and the aqueous liquid are separated into two layers, and the inorganic substance fine particles and the oily substance floating in the oily liquid layer move to the aqueous liquid phase, and the oily liquid layer It is desirable to wait until is clear. The clear oily liquid separated into two layers and the aqueous liquid in which the inorganic substance fine particles and the oily substance are coagulated and mixed are separated by various methods. As a matter of course, when the clarified oily liquid is circulated and used, it should be separated while avoiding the mixing of the aqueous liquid in which inorganic fine particles and the oily substance are intensively mixed. By this method, an oily liquid that can be easily circulated can be recovered without being purified by distillation.
The recovered oily liquid is preferably filtered before reuse. On the other hand, an aqueous liquid in which inorganic fine particles and an oily substance are concentrated and mixed can be separated into a cake-like lump of an inorganic substance including an aqueous liquid and an oily substance by a method such as centrifugation or filtration. Aqueous liquids can be circulated or drained into sewers and rivers if they are purified until they meet drainage standards. In addition, the volume can be reduced to a cake-like lump of inorganic substance including oily substance by natural drying without centrifugation or filtration. If the cake-like lump of inorganic substance including oily substance cannot be recycled, it will be treated as industrial waste, but compared to the original oily liquid, aqueous liquid and oily substance mixed. Therefore, it can be said that the volume of waste treatment has been remarkably reduced, and the burden on the global environment has been reduced.

  The embodiment of the present invention is not limited to the above. If a viscous oily substance is mixed as a contaminant only in the oily liquid, add an appropriate amount of water and inorganic fine particles, stir and mix, and leave to stand to recover a clear oily liquid. It can be separated into two layers and separated into a clear oily liquid and an aqueous liquid in which inorganic fine particles and an oily substance are coagulated and mixed. In addition, in order to remove oily substances mixed in aqueous liquids and organic substances dissolved in water, an appropriate amount of oily liquids and inorganic fine particles are added, mixed with stirring, and left to stand to separate two layers. Thus, it can be separated into an oily liquid, an aqueous liquid in which inorganic fine particles and an oily substance are aggregated and mixed, and the oily substance can be easily removed from water by filtering or centrifuging the aqueous liquid side. In addition, the method of the present invention is not limited to the treatment of various waste liquids, waste oils, and wastewaters, but is useful for oil-water separation cleaning purification in various chemical processes, food processing processes, pharmaceutical manufacturing processes, and the like.

  An oil-water separation and cleaning apparatus can be manufactured using the method of the present invention. For example, as shown in FIG. 1, a function of adding inorganic substance fine particles having a lipophilic surface to a state where an oily liquid, an aqueous liquid and an oily substance are mixed, and a function of stirring and mixing; An oil-water separation and cleaning apparatus having a function of separating two layers of an oily liquid and an aqueous liquid. The other is, as shown in FIG. 2, a function of adding inorganic substance fine particles having a lipophilic surface to a state where an oily liquid, an aqueous liquid and an oily substance are mixed, and a function of stirring and mixing, and a function of standing still An oil / water separation and cleaning apparatus comprising a function of separating two layers of an oily liquid and an aqueous liquid, and a function of separating inorganic fine particles and an oily substance from the aqueous liquid layer to obtain water or an aqueous liquid. For stirring and mixing, it is important not to create a blind spot that is not stirred in the stirring tank, and it is possible to shake the entire container instead of stirring. Centrifugation can be preferably used as a separation function in order to shorten the standing time or to minimize the volume of industrial waste composed of inorganic fine particles and oily substances. When reusing a clarified oily liquid, it is desirable to suck out the oily liquid in the upper layer of the container in order to prevent remixing of aqueous liquids, inorganic fine particles, oily substances, etc. It is also desirable to filter before.

  According to the present invention, various waste liquids, waste oils, and wastewaters contaminated with viscous oily substances can be separated by oil and water very easily and inexpensively, and the purified oily liquid can be reused. Aqueous liquids can be cleaned and drained, and industrial waste emissions are significantly reduced.

Add fine inorganic substance particles with lipophilic surface to various waste liquids, waste oils, and wastewaters contaminated with viscous oily substances, stir and mix, and after standing, separate the layers, and are in the upper layer, close to clarification or near clarification Separating and collecting the oily liquid in a state, filtering it if necessary, and reusing it was realized with a simple operation.
The following examples illustrate the invention.

  Add 100 ml of blanket / roll cleaning waste liquid in offset printing to a 300 ml Erlenmeyer flask, add 6 g of colloidal calcium carbonate with an average particle size of 0.08 microns and DOP oil absorption of 26.0 ml / 100 g, shake the flask for 2 minutes, I put it. The washing waste liquid contains about 80% washing oil of medium and high boiling point petroleum solvent, about 18% moisture, and about 2% black ink. The oil layer and water layer appear to separate into two layers. The oily substance of thick black ink is contaminated across both layers. Within 1 hour after standing, a clear and transparent liquid appears in the upper layer and separates from the lower black layer. If left overnight, the clear and transparent liquid layer is about 80% in the upper layer and the black liquid in the lower layer. Clearly separated into about 20% layer. When the upper layer was analyzed by gas chromatography, it coincided with the components of the washing oil of the medium and high boiling point petroleum solvent used as the washing liquid. When the lower layer black liquid was separated and centrifuged, it was separated into about 7 g of a black solid and an aqueous liquid. It was 250 ppm when COD of aqueous liquid was measured with the simple test paper.

The washing waste liquid used in Example 1 and the following various inorganic substance fine particles were added in the same manner as in Example 1, stirred and mixed, and allowed to stand to observe the state of two-layer separation. In either case, the upper layer was separated into a clear and transparent medium-high boiling petroleum solvent washing oil in the upper layer and a black to gray viscous liquid layer in the lower layer.
Inorganic substance fine particles A: light calcium carbonate; average particle size 1.5 microns,
Inorganic substance fine particles B: heavy calcium carbonate; average particle size 1.5 microns, calcium stearate 1% surface-treated inorganic material fine particles C: porous calcium carbonate; average particle size 3 microns,
Inorganic substance fine particle D: Kaolin clay; average particle size 1.5 microns,
Inorganic substance fine particle E: calcium sulfate; average particle diameter 1 micron, calcium stearate 1% surface treatment

  Useful components such as printing washing waste liquid, painting waste liquid, various washing process waste liquid, various purification process waste liquid, etc., which are mixed with a lot of solvents and water, are useful and recycled, and the water can be drained into general sewers and rivers at low cost and simple. Thus, it is useful as a space-saving waste liquid treatment method.

It is explanatory drawing of the oil-water separation washing | cleaning apparatus which collect | recovers oily liquid from the waste liquid in which oily liquid, aqueous liquid, and an oily substance are mixed. It is explanatory drawing of the oil-water separation washing | cleaning apparatus which isolate | separates an oily substance and an inorganic substance fine particle from an aqueous liquid after collect | recovering an oily liquid from the waste liquid in which an oily liquid, an aqueous liquid, and an oily substance are mixed.

Explanation of symbols

A A mixture of oily liquid, aqueous liquid, and oily substance B Inorganic substance fine particle C Reusable oily liquid D Aqueous liquid + oily substance + inorganic substance fine particle E Aqueous liquid F Oily substance + inorganic substance fine particle

Claims (10)

  Add inorganic fine particles with lipophilic surface in a state where oily liquid, aqueous liquid and oily substance are mixed, stir and mix, and then leave to settle so that the inorganic fine particles and oily substance settle in the aqueous liquid phase. A method for separating and washing oil and water, wherein the oily liquid and the aqueous liquid are separated into two layers by moving.   A method for separating and washing oil and water, wherein the surface of the inorganic fine particles according to claim 1 is subjected to lipophilic surface treatment.   2. The oil-water separation and cleaning method according to claim 1, wherein the average particle size of the inorganic substance fine particles is 10 microns or less.   4. An oil-water separation and cleaning method, wherein the average particle size of the inorganic fine particles of claim 3 is 3 microns or less.   4. An oil-water separation and cleaning method, wherein the inorganic fine particles according to claim 3 have an average particle size of 0.1 microns or less.   The method for separating and washing oil and water according to claim 3, wherein the inorganic fine particles are calcium carbonate.   A method for separating and washing oil and water, characterized in that the inorganic substance fine particles according to claim 3 are porous calcium carbonate having an average particle size in the range of 1 to 10 microns.   The state in which the oily liquid, the aqueous liquid and the oily substance are mixed in the first aspect is such that the ratio of the oily liquid is 20% by weight or more and less than 100% by weight, and the oily substance is a waste liquid having a higher viscosity than the oily liquid. A method for separating and cleaning oil and water.   The function of adding inorganic substance fine particles having a lipophilic surface to a state where an oily liquid, an aqueous liquid, and an oily substance are mixed, stirring and mixing, a function of standing still, and a function of separating two layers of an oily liquid and an aqueous liquid An oil-water separation and cleaning device comprising:   The function of adding inorganic substance fine particles having a lipophilic surface to a state where an oily liquid, an aqueous liquid, and an oily substance are mixed, stirring and mixing, a function of standing still, and a function of separating two layers of an oily liquid and an aqueous liquid An oil-water separation and cleaning apparatus comprising a function of separating inorganic fine particles and an oily substance from an aqueous liquid layer to obtain water or an aqueous liquid.

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