JPS595328B2 - Treatment method for petroleum-based water-containing waste oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating hydrous petroleum waste oil.

More specifically, the present invention relates to a method for treating petroleum-based water-containing waste oil, which forms an emulsion consisting of petroleum-derived oil, moisture, and sludge.

Conventionally, rolling processes, pipe manufacturing processes, coke oven gas cleaning processes using petroleum-based absorption oil in steel mills, rolling waste oil, lubricating waste oil, cleaning waste oil from T machine factories, etc., crude oil tanks at oil refineries and petrochemical plants , Crude oil waste oil from the cleaning process of heavy oil tanks, etc., lubricating oil manufacturing process, etc., heavy oil waste oil, tank residual oil, mixed oil, etc., lubricating waste oil from automobile factories, machine manufacturing factories, shipyards, etc., automobile engine oil waste oil, cutting A large amount of petroleum-based water-containing waste oil, such as oil and anti-corrosion oil, is generated.

These petroleum-based water-containing waste oils have slightly different properties depending on where they are generated, but they usually contain not only oil and water but also solid sludge and other additives such as emulsifiers.

This forms an extremely stable emulsion.

For example, waste oil generated from the rolling process, coke oven gas cleaning process, machine tool factory, etc. in steel plants is mixed oil mainly composed of petroleum oils such as rolling oil, lubricating oil, machine oil, cleaning oil, etc. Water-in-oil type (hereinafter referred to as W2O type) consisting of water and fine powder solids such as iron oxide, carbon, etc.

) is an emulsion. In addition, waste oil, mixed oil, etc. generated from the cleaning process of crude oil tanks, heavy oil tanks, etc. in oil refineries, as well as waste oil generated from machine manufacturing factories and other places, are almost the same water-containing waste oil in the form of W10 emulsion. The composition of these water-containing waste oils is usually 50% by weight or more of petroleum oil, 0.1 to 1.0% by weight of solids (in terms of dry content),
The remainder is water.

Petroleum-based oil refers to oil mainly consisting of non-aromatic oil.

The solid content includes metal powder such as iron powder, iron compounds such as iron oxide, carbon, dust, sand, and the like.

The solid content exists as sludge with oil or water attached.

Even if these water-containing waste oils are forcibly separated using a centrifuge, the oil, emulsion, and
Its treatment is extremely difficult since the water and solids proportions change little over time.

In addition, this water-containing waste oil has poor combustibility, so it is less efficient as a fuel, and the sludge may clog the burner tip.

As a method for treating such emulsion-type petroleum-based water-containing waste oil, the waste oil is heated and pressurized, then cooled, separated into three layers of oil, water, and solids, and each layer is centrifuged. 47722), a method of heating waste oil to destroy the emulsion, and separating each layer after cooling (% Kosho 51-
No. 43305), waste oil is centrifuged under heating to
A method of centrifuging water and sludge and then further centrifuging the obtained oil and water (Japanese Patent Laid-Open No. 52-123403)
No. 2) has been proposed.

However, these methods not only require a large amount of energy for heating, pressurization, centrifugation, etc., but also are insufficient in separating sludge and oil.

In addition, after adding light petroleum fraction to the mixed oil and extracting the oil,
A method in which the resulting deoiled mixed oil is heated or treated with a flocculant and centrifuged to separate water and solids (Japanese Patent Publication No. 47-15
025 Publication), a method of adding and mixing a hydrocarbon solvent mainly composed of hydrocarbons from propane to light oil to waste oil and separating it into oil and sludge (Japanese Patent Laid-Open No. 49-39601
No. 2) has been proposed.

However, these methods also have the disadvantage that the separation of sludge and oil is insufficient.

The present invention was made in order to eliminate the various drawbacks of the conventional methods as described above. After adding 100 to 500 Qppm of oil containing 50% by weight or more of group hydrocarbons and an anionic or cationic surfactant to the water-containing waste oil,
This is a method for processing water-containing petroleum waste oil, which is characterized by separating the oil content.

That is, according to the findings of the present inventors, if a specific solvent consisting of an oil containing 50% by weight or more of aromatic hydrocarbons and a specific surfactant are added and mixed to water-containing petroleum waste oil, the above-mentioned stability can be achieved. The W10 type emulsion with high viscosity is destroyed, resulting in good sludge settling properties and good separation from water.

The oil can be separated by allowing the mixture to stand still.

In addition, it has been found that centrifugation can quickly remove the sludge, and after the sludge has been removed, the oil-water mixture is left to stand, making the interface between the layers clearer, resulting in better oil-water separation. did.

However, when comparing various types of solvents to be added, it was found that the separation effect of aliphatic hydrocarbon oils, including naphtha, kerosene, light oil, and heavy oil, was unsatisfactory.

Therefore, in the present invention, the solvent used for breaking the emulsion contains 50% by weight or more of aromatic hydrocarbons,
Any aromatic oil containing preferably 70% by weight or more can be used.

For example, light oil obtained by absorbing coke oven gas with absorption oil, light oil obtained by fractional distillation of coal tar, reformed oil obtained by aromatizing petroleum naphtha, and fractional distillation of these oils. These include crude to purified benzene, toluene, solvent naphtha, naphthalene oil obtained from coal coeur, absorption oil, anthracene oil, creosote oil, and mixtures thereof.

Among these, aromatic oils containing mainly fractions with a boiling point of 130 to 275°C are effective, and aromatic oils containing 20 to 60% naphthazine are particularly effective.

Such aromatic oils include residual oils obtained by distilling the fractions from tar gas oil to xylene.

The amount of these aromatic oils added depends on the amount of oil in the water-containing waste oil,
It is selected depending on the amount of sludge, treatment conditions, and treatment equipment, but generally it is 1% by volume or more, preferably 1 to 50% by volume, based on the oil content in the water-containing waste oil.

Although the upper limit of the amount added is not regulated from the separation effect, using too much is disadvantageous from an economic point of view.

Furthermore, if an anionic or nonionic surfactant is used together with the above solvent, the amount of solvent added can be reduced to about one-tenth.
It can be reduced to a certain extent.

As an anionic surfactant, fatty acid salt R1R1CH
2COO However, R1 is an alkyl group or alkenyl group having 11 to 17 carbon atoms, and M is Na or K.

) Triethanolamine sulfonate or sodium sulfonate R2503Na (wherein R2 is an alkyl group having 12 to 18 carbon atoms).

), R37S Os Na (where R3 is an alkyl group having 11 to 15 carbon atoms).

), R' 3 S Os Na (however, gourd is an alkyl group having 1 to 4 carbon atoms.

)R5CHC00H (however, R6 has 11 to 11 carbon atoms)
03Na 17 is an alkyl group.

), R6C00H2SO3Na (wherein R6 is an alkyl H3 group having 11 to 17 carbon atoms).

), R7C0N) (CH2SOs Na (However, R
7 is an alkyl group having 11 to 17 carbon atoms.

), R600CCH8OsNa (however, R8 and Kawa's total n'800CCH2 is an alkyl group with a total number of carbon atoms of 10 to 2o.

), lignin sulfonate, etc., higher alcohol sulfuric ester acids R0O8Oa Na (However, R9 is an alkyl group having 12 to 18 carbon atoms.

), RIO＼ R1o/CH°03 Na ("kfeL-Rt□#r
OR'to? i is an alkyl group having 12 to 18 carbon atoms.

), polyoxyethylene alkyl ether sulfate R1□
(CH20)nsO3Na (However, RH is an alkyl group having 8 to 18 carbon atoms, and n is an integer of 1 to 20.

), R1□00(CH2CH20)m SOsNa
(However, R12 is an alkyl group having 8 to 18 carbon atoms,
m is an integer from 1 to 20.

) and anionic surfactants such as alkyl succinate esters, poly(oxyethylene) glycol alkyl ether R13 (CH2CH20) n H (however, R
13 is an alkyl group having 6 to 30 carbon atoms, n is 3 to 12
It is an integer of 0.

), poly(oxyethylene)alkyl 9-lether R1400(CH2CH20)nH (wherein R14 is an alkyl group having 6 to 12 carbon atoms, and n is an integer of 3 to 120.

), poly(oxyethylene) alkyl ester R15C
00(CH2CH20)nH or R15-COo(C
H2CH2)-CH2CH2-COOR1, (however,
an alkyl group having 6 to 24 carbon atoms; n is an integer of 3 to 120;

), poly(oxyethylene)alkyluane R16-NH
(CH2CH20)nH (CH2CHzO)nHt? , = (iR4a Ns (
, H2oH2o), ■ (However, R16 has 6 carbon atoms
~30 alkyl groups, n and n' are integers from 3 to 120.

), poly(oxyethylene)alamide R17C0NH (CH2CH20) nH or R1,
-/ (CH2CH20) nH CON\(CH2CH20)n'H(”'= ”' ”
an alkyl group having 6 to 30 carbon atoms, n and n' are 3 to 30;
It is an integer of 120.

), poly(oxyethylene) solhytan acid ester (however, R18 is an alkyl group having 6 to 24 carbon atoms,
n is an integer from 3 to 60.

), Pluronic poly(oxyethylene)-poly(
oxypropylene) cocondensate HO (CH2CH20) a (CH2CH2020) b (CH2CH20) cH (
However, a.

b and c>1 and (a+b+c)=20-400.

), the co-condensate of the tetronic type (however, X-2 and V-y > 1, x + x + x'+ x'''+ y
+y'+y'+y'=20-800.

] and other nonionic surfactants.

The amount of these surfactants added is 10% to the water-containing waste oil.
0 to 5000 ppm, preferably 500 to 200
It is oppm.

If the surfactant is water-soluble, it can be added as a 1-10% aqueous solution, and if it is oil-soluble, it can be added as a undiluted solution or dissolved in a tar-based solvent.

Particularly good results are obtained when such treatment of water-containing waste oil with a solvent and a surfactant is carried out at a pH of 4 to 8, preferably 6 to 7.

After adding the above-mentioned aromatic oil and surfactant to the water-containing waste oil, it is necessary to sufficiently stir and mix them to improve contact mixing, and it is preferable to heat them during this mixing.

As a mixing method, Rengi's methods such as circulating in a tank using a pump or using a line mixer may be used.

It is preferable to heat the waste oil to a high temperature within a range where vaporization of the oil and solvent in the waste oil does not become a problem, and for practical purposes it is from room temperature to 90°C.
, preferably 50 to 70°C.

After such aromatic oil and surfactant are added and mixed, if the mixture is allowed to stand still, the oil will separate.

Further, after adding and mixing such an aromatic oil and a surfactant, if sludge is removed by centrifugation or the like, the oil-water separation effect is further improved.

Centrifugation is suitable as a method for removing sludge.

The higher the centrifugal force is, the better the separation effect will be, but it is usually 1000G or more, and from an economical point of view, preferably 2000 to 4000G.

It is preferable to separate the sludge when applying this centrifugal force.

Various types of centrifugal separation can be used to simultaneously separate sludge, but filtration type equipment that is not a surface renewal type is prone to clogging problems due to sludge; Complete separation of sludge is difficult.

Therefore, it is preferable to use a centrifugal sedimentation type.

If the R-liquid from which sludge has been removed by a centrifugal separator is allowed to stand, almost no emulsion layer will remain at the interface, and it will separate into two layers: an oil layer at the top and a water layer at the bottom, and the oil and water will be separated easily. It can be collected and separated.

The oil thus recovered can be used at least as fuel oil, and depending on the source of the waste oil, it can be used for more valuable applications.

On the other hand, since the amount of oil mixed in with water is only the dissolved amount, it can be purified by activated sludge treatment without any special pretreatment.

Next, the method of the present invention will be explained in more detail with reference to Examples.

Example 1 and Comparative Examples 1 to 2 Specific gravity at 4°C is 0.842, elemental analysis value C8
5.3%, H137%, oil content 73% by weight, moisture 2
6% by weight and solid content such as iron oxide (converted to dry state) 12
A predetermined amount of steel mill waste oil and additives, which are mixed waste oils mainly composed of petroleum oils such as rolling oil and machine oil, forming a W10 type emulsion, and additives are charged into a 5Qcc centrifugal sedimentation tube. , and heated in a 60° C. water bath for 30 minutes with occasional stirring.

Then, centrifugal sedimentation was performed at 1250 G for 15 minutes in a hanging centrifuge.

The far-flood/settlement tube was taken out and the volumes of the oil layer, the intermediate layer between the oil layer and the water layer (emulsion), the water layer, and the sedimentation layer (solids→moisture) were read.

The results of experiments conducted with different types of additives are shown in Table 1.

Examples 2 to 6 and Comparative Examples 3 to 4 Specific gravity at 4°C is 0.835, elemental analysis value C8
5.5%, HI 3.2%, oil content 55% by weight, moisture 44% by weight 70%, and solid content such as carbon (dry state) 15% by weight, petroleum oil such as coke oven gas cleaning oil, etc. A centrifugal separation test similar to that in Examples 1 and 2 was conducted on steel mill waste oil, which is a mixed waste oil mainly composed of , which forms an emulsion, with the addition of additives.

The results were as shown in Table 2.

Example 7 A liquid in which 20% by volume of the tar-based mixed oil (■) in Example 1 and 200 Qppm of dioctyl sulfosuccinate sodium salt was added to steel mill waste oil having the same composition as in Example 2 was heated on a heating table at 70°C for 30 minutes. .

Next, this liquid was filtered through a 1103 glass filter at 250%
When vacuum filtration was carried out under a pressure of ~300 mmHf, filtration was possible even after 150 minutes or more, and the amount of filtrate up to 150 minutes was 73 ml.

This liquid f easily separated into oil and water.

Examples 8 to 14 and Comparative Examples 5 to 6 Regarding steel mill waste oil similar to Example 1, residual oil (boiling point approximately 140 to
230℃) was added to the waste oil at 30% and a surfactant, mixed, heated at 70℃ for 30 minutes, and then heated at 1250G for 1
A 5 minute centrifugation test was performed.

The results are shown in Table 3.

Example 15 Fractions from tar light oil to xylene were added to 1 part of automobile engine oil waste oil (composition determined by centrifugation method: oil content: 91.7% by volume, moisture: 3.8% by volume, sediment: 4.5% by weight). 0.02 part of the distilled residual oil (boiling point 140-230°C) and 2000 p of sodium dodecylbenzenesulfonic acid triethanolamine salt were added, and after heating and stirring, one centrifugation test was conducted.

As a result, 0.91 parts of oil, 0.04 parts of water, and 0.007 parts of sediment were recovered.

After addition and mixing, a heating and standing test was conducted at 80° C. for 2 hours, and a clean oil layer of 0.7 volumes was formed in the upper layer.

Furthermore, when it was left to stand at room temperature for 24 hours, the oil layer became over 0.8 volumes.

When only the waste oil was heated and left at 80°C, no change occurred even after 2 hours.

Claims (1)

[Scope of Claims] 1. Aromatic hydrocarbons containing 50% by weight or more of aromatic hydrocarbons in petroleum-based water-containing waste oil that forms a water-in-oil emulsion consisting of petroleum-derived oil, water, and solid components such as sludge. A method for treating petroleum-based water-containing waste oil, which is characterized by adding 100 to 5,000 PP" of oil and an anionic or nonionic surfactant to the water-containing waste oil to separate the oil. 2. Adding aromatic oil. After that, the sludge content is removed using centrifugal force, and then the oil content and water content are separated by a static separation method. 3. The amount of aromatic oil added is The method according to claim 1, in which the method is used in an amount of 1% by volume or more based on the oil content in the water-containing waste oil. 4. The method according to claim 1, in which the addition and mixing is performed at a temperature of room temperature to 90°C. 5. The method according to any one of claims 1 to 3, wherein the addition and mixing is performed at a temperature of 50 to 70°C. 6. The addition and mixing is carried out at a temperature of 50 to 70°C. The method according to any one of claims 1 to 5, in which the pH is adjusted to 4-8. The method according to any one of Items to Items 5. 8. Claim 1, wherein the centrifugal force is 100 OG or more.
The method described in any one of paragraphs 7 to 7. 9. The method according to any one of claims 1 to 8, wherein the aromatic oil is mainly a fraction with a boiling point of 130 to 275°C. 10. The method according to claim 9, comprising 20 to 60% naphthalene in an aromatic oil. 11. The aromatic oil is a residual oil obtained by distilling a fraction obtained by distilling tar or a fraction from light oil collected from coke oven gas to xylene, according to claim 9. Method.