JP3134128B2 - Method to remove chlorine-based solvent mixed in mineral oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a chlorine-based solvent contained in a mineral oil (mainly waste oil) used for various purposes.

[0002]

2. Description of the Related Art Chlorinated solvents have excellent dissolving performance and therefore have many uses, such as metal parts, machinery, electronics industry,
It is used in the cleaning industry, etc. for the purpose of degreasing, extracting, and washing, and is also used as a metal surface treatment agent and paint remover. At present, a large amount of waste oil containing mineral oil is discharged.

[0003] As described above, almost all of the waste oil of the mineral oil containing a chlorine-based solvent used for degreasing and cleaning of metal parts and the like has been incinerated and disposed of in a dedicated furnace. The reason is that when a chlorine-based solvent is contained, the waste oil of the mineral oil is not easily twisted, and at the same time, has a problem of corrosion of equipment due to combustion gas, and cannot be used as fuel oil.

Therefore, in some cases, this waste oil is distilled to regenerate only the chlorinated solvent and recycled, but undistilled chlorine is contained in the mineral oil remaining in the still. The residual solvent is contained at a considerable content, and there is no other method of treating this residual oil except incineration, and many mineral oil waste oils are incinerated without being effectively used.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to develop a method for almost completely removing a chlorine-based solvent from a mineral oil containing a chlorine-based solvent as described above (mainly waste oil). Is what you do.

[0006] Investigation of past patent publications and the like for this development reveals that no technology having such a problem has been disclosed at all, and the problem itself of almost completely removing chlorine-based solvents from this waste oil has been identified. It was determined that this was a new technology, and if this could be solved, waste oil could be reused as fuel oil, enabling recycling and also effective in preventing environmental pollution, and would be an extremely useful new technology. It is.

That is, the present invention provides a method for removing a chlorine-based solvent from a mineral-based oil mixed with a chlorine-based solvent, which has been conventionally discharged and incinerated in large quantities, to promote resource reuse and environmental protection. It is to try to.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, it was found that a method for removing a chlorine-based solvent by an azeotropic distillation method using a versatile solvent was suitable. Further investigations have found that, particularly when xylene is used as a solvent for the azeotropic distillation, extremely efficient removal of a chlorine-based solvent can be achieved.

That is, the present invention is characterized in that xylene is blended into a mineral oil containing a chlorine solvent and the chlorine solvent is removed by a solvent azeotropic distillation method. And a method for removing the chlorinated solvent.

The chlorinated solvent contained in the mineral oil (mainly waste oil) before being regenerated by the method of the present invention is mainly trichloroethane, trichloroethylene, tetrachloroethylene, methylene chloride, etc. It is lower than the boiling point of xylene. Also,
The boiling point of the mineral oil itself in the waste oil treated according to the present invention is higher than the boiling point of xylene. If the waste oil to be regenerated contains moisture and other contaminants, it is pretreated by a centrifugal separator or the like in order to precipitate the sludge in the still and reduce the thermal efficiency. It is desirable.

On the other hand, as the xylene used in the present invention, industrial xylene is usually sufficient, and ortho-xylene (boiling point: 144.2 ° C.) and meta-xylene (boiling point: 139.1)
C.) and para-xylene (boiling point 138.4 ° C.), the boiling point of which is about 137 to 143 ° C.

[0012] In addition to the xylene, toluene, benzene and the like have been studied as the azeotropic solvent. It has been found that the use of this xylene as the azeotropic solvent is most suitable as in the examples described later. It was done. This is thought to be because xylene has a higher boiling point than chlorinated solvents and a lower boiling point than mineral oil, and benzene and toluene may have lower boiling points than chlorinated solvents. If the boiling solvent evaporates before the chlorine solvent, the amount of the chlorine solvent remaining in the mineral oil increases.

As described above, xylene is suitable as the azeotropic solvent of the present invention in terms of boiling point, is more suitable than other azeotropic solvents in terms of toxicity and flammability, and is easily available and versatile. Is also preferred.

Next, the amount of xylene to be blended into the mineral oil to be treated (mainly waste oil) is such that the larger the blending amount is, the more the residual amount of chlorine-based solvent in the regenerated mineral oil is The experimental result was that it was less. Further, it has been confirmed by experiments that the amount of xylene remaining in the regenerated mineral oil is 10 to 15% by volume. Therefore, it is determined that it is desirable to mix at least 20% by volume or more of xylene. You.

On the other hand, as the amount of xylene increases, the effect of removing the chlorine-based solvent increases. However, if the amount of xylene is too large, the azeotropic distillation takes too much time. % Is considered to be suitable. The above range is not particularly limited, and the allowable amount of the chlorinated solvent in the regenerated mineral oil is determined by the amount and type of the chlorinated solvent contained in the waste oil to be regenerated. Therefore, the amount of the xylene may be appropriately determined in accordance with these factors.

In this manner, an appropriate amount of xylene is blended with the waste oil of the mineral oil and distilled by a usual solvent azeotropic distillation method. That is, the blended liquid is charged into a still pot, distillation is performed, and distillate components are collected by cooling with a cooling pipe with water. It is desirable that zeolite be charged in the distillation still to prevent bumping.

As the temperature of the solvent azeotropic distillation gradually increases, the azeotropic distillation starts from 120 to 150 ° C., although it depends on the amount and type of the chlorine-based solvent contained. It is desirable to carry out distillation at a maximum temperature (oil temperature) of 180 to 200 ° C. If the maximum oil temperature exceeds 200 ° C., the mineral oil is decomposed and deteriorated, which is inappropriate. Therefore, usually, when the oil temperature is 200
When the temperature reaches ° C, it is desirable that the azeotropic distillation is judged to be almost completed and the azeotropic distillation of the solvent be terminated.

After completion of the azeotropic distillation, the recovered liquid collected as the distilling solvent is a mixture of xylene and a chlorine-based solvent. Can be reused as xylene, and if the recovered liquid contains a large amount of chlorinated solvent from the beginning or is reused many times, this recovered liquid is redistilled and separated into xylene and chlorinated solvent. Then, the recovered xylene may be reused.

On the other hand, the bottom oil (reclaimed oil) after the end of the azeotropic distillation
Is that the chlorine-based solvent is almost completely removed.
That is, as in the examples described later, when the total chlorine was quantified by a chlorine analyzer and the amount of the remaining chlorine-based solvent was determined, the removal rate was reduced when the chlorine-based solvent was trichloroethane, trichloroethylene, or methylene chloride. 9
It is 9.9% or more, and the removal rate of even the most difficult-to-remove tetrachloroethylene reaches 99% or more, and this treated regenerated oil can be sufficiently used as fuel oil. (However, it can be said that these removal rates are substantially 100% in consideration of the chlorine content initially contained in the mineral oil based on judgment from the examples described later.) The azeotropic temperature is 200. C. or less, the regenerated oil contains a residual amount of xylene of 10 to 15% by volume, but there is no problem in using it as a fuel oil.

Since xylene is contained in an amount of 10 to 15% by volume, this regenerated oil has a decrease in viscosity and a decrease in flash point. When used other than fuel oil, xylene is distilled off under reduced pressure if necessary. It is also possible to remove it.
Further, if the solvent azeotropic distillation method of the present invention is azeotropic distillation by vacuum distillation, the distillation temperature may be low and the residual amount of xylene can be greatly reduced.

[0021]

EXAMPLE An engine oil used for a passenger car was used as a mineral oil, and trichloroethane, trichloroethylene, tetrachloroethylene, and methylene chloride were each 10% by volume based on the engine oil as described below.
The mixed ones were prepared to obtain four types (a, b, c, d) of simulated waste oils. a; engine oil 90 cc + trichloroethane 10 cc b; engine oil 90 cc + trichloroethylene 10 cc c; engine oil 90 cc + tetrachloroethylene 10
cc d; 90cc engine oil + 10cc methylene chloride

Xylene, toluene and benzene were respectively blended as azeotropic solvents with these four kinds of simulated waste oils, and the test numbers were given as follows. Test No1 Waste oil a 100cc + Xylene 100cc Test No2 Waste oil b 100cc + Xylene 100cc Test No3 Waste oil c 100cc + Xylene 100cc Test No4 Waste oil d 100cc + Xylene 100cc

Test No.5 100cc of waste oil a + 100cc of toluene Test No.6 100cc of waste oil b + 100cc of toluene Test No.7 100cc of waste oil c + 100cc of toluene Test No.8 100cc of waste oil d + 100cc of toluene

Test No. 9 Waste oil a 100 cc + benzene 100 cc Test No. 10 Waste oil b 100 cc + benzene 100 cc Test No 11 Waste oil c 100 cc + benzene 100 cc Test No 12 Waste oil d 100 cc + benzene 100 cc This is to unify evaluations as comparative data.

As described above, a mixture of 12 kinds of test Nos. Was subjected to azeotropic distillation under the same conditions. That is, each mixed solution was charged in a distillation flask, zeolite was charged, and the oil temperature was 2
Distillation was performed while heating with a mantle heater until the temperature reached 00 ° C., and the distillate was water-cooled with a condenser and collected with a measuring cylinder.

After cooling the bottom oil (reclaimed oil) in each of Test Nos. 1 to 12, the total amount of residual chlorine was measured by a chlorine analyzer, and the residual chlorine weight%, the residual capacity of the chlorine-based solvent (cc),
And the percentage of chlorine-based solvent removal were calculated. These data are summarized in Table 1.

[0027]

[Table 1]

From Table 1 above, it can be seen that the chlorine-based solvent mixed in the mineral oil can be removed by azeotropic distillation with an azeotropic solvent. In particular, when xylene is used as the azeotropic solvent, the extremely excellent removal of the chlorine-based solvent can be achieved. It is recognized that it can be achieved. By the way, the engine oil itself used in this example contained a chlorine-based extreme pressure additive, and about 0.0038% by weight of chlorine was present from the beginning. Taking into account the chlorine content from the beginning, the results in Table 1 show that a slight chlorine content still remains even with the method of the present invention, but the chlorine-containing solvent substantially mixed in It can be determined that it has been completely removed.

[0029]

The present invention is as described above, and its effect raises a new problem that has been overlooked in the past, namely, the problem of removing a chlorine-based solvent contained in a mineral oil. , And have solved it. Therefore, according to the method of the present invention, it is possible to almost completely remove a chlorine-based solvent from a mineral oil containing an arbitrary amount of a chlorine-based solvent, and the treated reclaimed oil can be used as a fuel oil. It becomes. As a result, waste oil, etc., which could only be incinerated by a dedicated furnace in the past as a final disposal method, can now be regenerated as fuel oil.This will enable the reuse of resources and prevent environmental pollution due to incineration. It is extremely useful.

Claims (1)

(57) [Claims] 1. A chlorine-based oil mixed in a mineral oil, wherein xylene is blended with a mineral oil containing a chlorine-based solvent and the chlorine-based solvent is removed by a solvent azeotropic distillation method. A method of removing the solvent.