JP2000169862A - Purification of waste oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for purifying waste oil by efficiently, inexpensively and economically removing the waste oil containing a metal compound and an organic halogen compound such as chlorine without requiring a specific high-temperature and high-pressure apparatus, a catalyst, hydrogen gas, or the like, or without generating secondary waste, or the like, difficult to treat. SOLUTION: This method for purifying waste oil comprises mixing waste oil containing a metal compound and/or an organic halogen compound with coal to afford mixed slurry, heating the raw material slurry and absorbing the metal compound and/or the organic halogen compound into coal. Further, the metal compound and/or the organic halogen compound in the waste oil is absorbed by a polar group in coal and the amount of the polar group is >=15 wt.% based on total oxygen content of carboxyl group, hydroxy group and carbonyl group per coal when excluding water content and ash content therefrom. The waste oil is preferably heated at 150-400 deg.C before mixing with coal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying a waste oil containing a metal compound and an organic halogen compound by removing the same from the waste oil. Specifically, by utilizing coal having a large number of polar groups that are considered to have a low economic value, metal compounds and organic halogen compounds in waste oil are adsorbed to the polar groups in the coal to remove these compounds. The present invention relates to a method for refining waste oil.

[0002]

2. Description of the Related Art In the field of petroleum refining, the "sulfuric acid treatment method" using sulfuric acid has been widely used in the past when performing final finishing processes such as removal of metal components, chlorine components and heavy substances in waste oil. . However, this sulfuric acid treatment method has hardly been practiced recently because of low product yield and difficulty in treating sulfuric acid used.

[0003] A "soil treatment method" using clay or activated coal for the purpose of removing sludge, decolorizing, deodorizing, etc. is also widely used. This clay treatment method is relatively effective in removing sludge, decolorizing, deodorizing, etc., but in terms of removing metal components and chlorine in waste oil, a satisfactory removing effect cannot be obtained, There is a new problem that it is difficult to treat secondary waste such as waste clay.

[0004] In recent years, the "distillation method" for removing heavy substances by distillation; and the "contact method" for contacting hydrogen under high-temperature and high-pressure conditions in the presence of a catalyst, have become the mainstream of such a removal method. . Among them, the former “distillation method” has an economic problem that when a lubricating oil is used, a vacuum distillation method must be used because of its high boiling point, and the cost increases. Also,
Even in the latter "contact method", since hydrogen is used at a high temperature and a high pressure, a large cost is required for fixed costs such as facility costs and operation costs, and it is not economically feasible at present.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to eliminate the need for a special high-temperature and high-pressure apparatus, a catalyst, hydrogen gas, etc. It is an object of the present invention to provide a method for purifying waste oil by efficiently, inexpensively and economically removing the same from waste oil containing a metal compound and an organic halogen compound such as chlorine without generating waste.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for refining waste oil which has solved the above-mentioned problems, by mixing waste oil containing a metal compound and / or an organic halogen compound with coal to obtain a raw material slurry. The gist lies in refining the waste oil by heating the raw slurry to adsorb the metal compounds and / or organic halogen compounds in the waste oil onto coal.

This method is intended to adsorb the metal compound and / or the organic halogen compound in the waste oil by the polar group in the coal. In order to obtain a desired adsorption effect, the amount of the polar group must be reduced. It is preferable that the total oxygen content of the carboxyl group, the hydroxy group and the carbonyl group based on the coal excluding water and ash is 15% by weight or more.

More specifically, waste oil containing a metal compound and / or an organic halogen compound is mixed with coal to obtain a raw slurry, and the treated slurry obtained by heating the raw slurry is subjected to solid-liquid separation. By removing the coal by the above method, a refined oil can be obtained. On the other hand, the coal chemically adsorbs a metal compound and / or an organic halogen compound and can be recovered as a by-product.

In the present invention, it is recommended that the waste oil be heated at a temperature of 150 to 400 ° C. before mixing the coal, thereby significantly improving the refining efficiency.

It is very useful to use the above-mentioned waste oil whose atomic moles satisfy the following formula, since the generation of hydrogen halide is remarkably suppressed.

[Halogen] / {[Ca] + [Mg] + [Ba]} ≦ 2 In the formula, [] indicates the atomic mole of each element contained in the waste oil.

In the practice of the present invention, a part of the refined oil obtained by subjecting the treated slurry to solid-liquid separation can be circulated and used as a medium for the raw material slurry. Further, water vapor generated by heating the raw material slurry may be collected and subjected to gas-liquid separation, and the gas phase may be pressurized and used as a heating source for the raw material slurry.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors, in providing a method for purifying waste oil capable of removing metal compounds and organic halogen compounds in waste oil, disclosed in Japanese Patent Application Laid-Open No. Hei 7-233376, which was previously filed. The study has been repeated based on the described method. This publication discloses a method for purifying oil in which impurities such as heavy oil components in the oil to be treated are adsorbed to and separated from hydrated porous coal such as lignite, and this method comprises dehydrating lignite in oil. At the time, impurities such as heavy oil in the oil phase are physically and selectively adsorbed to the vacant seats after the moisture in the pores present in the lignite is vaporized and dissipated by heating. It utilizes the physical adsorption phenomenon. The present inventors have further investigated the above method in order to achieve the object of "removal of metal components and halogen components such as chlorine in waste oil" set forth in the present invention, and as a result, carboxyl group, hydroxy group, carbonyl group, etc. The present inventors have found that the use of coal containing a polar group allows metal components and halogen components in waste oil to be adsorbed and removed not only physically but also chemically by the polar group in the coal, and the present invention has been completed.
As described above, the method of the present invention utilizes the removal action by physical adsorption and chemical adsorption. Are different.

Coal contains not only C and H but also O, N, S, etc., as is clear from the results of elemental analysis. Of these, the contents of N and S in coal are relatively small, and the O content in coal tends to increase as the degree of coalification decreases. Generally, anthracite has a C content of 90% or more, O content of 4% or less, and bituminous coal has an O content of 4-1.
Although it is said to be about 2%, the O content increases in sub-bituminous coal and lignite of lower quality than these coals. For example, the O content in lignite (weight ratio to lignite excluding moisture and ash) is approximately 20 to 30% by weight. However, in lignite or peat having a lower degree of coalification than lignite, the O content is low. Some exceed 30% by weight. This O is generally contained in a state of an oxygen-containing functional group such as a phenolic hydroxy group and an alcoholic hydroxy group, a carboxyl group, a carbonyl group, an alkoxy group, and ether oxygen.
Among these, hydroxy, carboxyl, and carbonyl groups have polarity and are relatively present in the coal. Further, N and S in coal have relatively small contents, but have polarity like O described above.

The present inventors have studied mainly on the in-oil dehydration method described in the above-mentioned publication, and as a result, it has been found that metal compounds and organic halogen compounds derived from additives and degraded products added to waste oil are present in coal. It has been found that they chemically adsorb to polar groups such as O, N, and S.

For example, lubricating oils generally contain additives such as detergents and dispersants, antioxidants, corrosion inhibitors, rust inhibitors, extreme pressure additives, defoamers, wear regulators, viscosity index improvers and the like. These additives include Ca, Mg, Zn, Ba, N
A compound containing a metal such as a, Ni, P, or Pb (including both a metal compound and an inorganic metal compound) and / or a compound containing a halogen such as chlorine (an organic halogen compound) may be used.

Of these, the organometallic compounds are generally contained in the above additives in the form of metal dithiophosphates, metal dithiocarbamates, metal sulfonates, metal phenolates, metal soaps, etc., and the inorganic metal compounds are metal sulfonates. And metal phenolates in the form of Me (OH) ₂ or MeCO ₃ (Me: metal).

On the other hand, typical examples of the organic halogen compound include chlorinated paraffin and chloronaphthozanthate containing chlorine and represented by the following formula.

[0019]

Embedded image

(Wherein, R represents an alkyl group and R ′ represents an alkylene group). These are representatively described below, and a metal compound or an organic halogen compound such as chlorine derived from the above-mentioned additive is used in these compounds. The mechanism of adsorption to a polar group in coal indirectly via a polar group existing in the coal or directly via the metal component will be described.

First, all of the above-mentioned metal dithiophosphates and metal dithiocarbamates are polar compounds, and the S atom bonded to P or C present in the compound has a negative charge. Is likely to chemically bond to the particles in the coal as a result of hydrogen bonding with the hydroxy groups in the coal.

Next, the metal sulfonate and the metal phenolate also have polarity, and the polar group is considered to be selectively adsorbed as a result of binding in such a manner as to be attracted to the polar group in coal. . Further, in the above metal compounds, the metal is bonded to the S atom and the O atom, and this metal is ion-exchanged with H in the carboxyl group present in the coal to obtain (COO) ₂ Me
In some cases, it is taken into coal in the form of (Me: metal).

The metal soap is (COO) ₂ Me
Although it exists in the form of (Me: metal), it is considered that this metal component is taken into coal by ion exchange with H of a carboxyl group in coal.

Further, a chlorine compound represented by chloronaphthazanthate or the like exists in a dithiocarbamate form, and an S atom bonded to a C atom has a negative charge. It is considered that this S atom forms a hydrogen bond with the hydroxy group in the coal, so that the entire additive containing the chlorine compound is adsorbed on the particles in the coal.

As described above, any metal compounds and organic halogen compounds present in the waste oil have polarity,
These are selectively adsorbed by forming a hydrogen bond with a polar group in coal or by chemically adsorbing the metal component in the additive by ion exchange with the polar group. it is conceivable that.

[0026] On the other hand, there are also those which are thermally decomposed during use to generate sulfides and phosphates, as represented by metal dithiophosphates and metal dithiocarbamates. Since these compounds are insoluble in oil, they exist as solids,
Those insoluble in water are removed by filtration together with the coal and removed. On the other hand, it is presumed that some of the water-soluble substances dissolve in the water in the coal pores, but precipitate as solids in the coal pores as the water evaporates, and are removed together with the coal.

Examples of the polar group include groups containing atoms exhibiting polarities such as O, N, and S. For example, oxygen-containing polar groups such as a carboxyl group, a hydroxy group, and a carbonyl group;
Examples include nitrogen-containing polar groups such as amino group and imino group; and sulfur-containing polar groups such as sulfonyl group and sulfinyl group. In order to effectively exhibit the ability to adsorb and remove metal components and halogen components, it is preferable to appropriately control the ratio of polar groups in coal. Specifically, in coal,
In particular, in consideration of the large O content, it is recommended that the total oxygen content of the carboxyl group, the phenol group and the carbonyl to the coal excluding moisture and ash is 15% by weight or more. If it is less than 15% by weight, a desired removal effect cannot be obtained.

In the present invention, the use of activated carbon, which is most widely used as an adsorbent, should be avoided as long as the activated carbon is produced under ordinary high temperature conditions. In general, activated carbon is generally used as a raw material from wood-based components such as wood and sawdust, but recently, coal-based raw materials have also attracted attention. This activated carbon is produced through main steps such as preparation of raw materials, coalification, and activation.
The activation is performed at a very high temperature of 700 ° C. and 800 to 1000 ° C. Therefore, even if a predetermined polar group is provided in the activated carbon, the polar group is completely decomposed under the above-described high-temperature production conditions, and the desired removal effect by the provision of the polar group can be effectively exhibited. Is not possible. Of course, if the activated carbon can be produced under such a temperature condition that the applied polar group is not decomposed, it goes without saying that such activated carbon is also included in the scope of "coal" in the present invention.

Here, it is recommended that the particle size of the coal used in the present invention is 1 mm or less. The smaller the particle size of the coal, the larger the surface area and the higher the contact efficiency between the waste oil and the polar group, thus improving the effect of removing metal compounds and organic halogen compounds. Will be higher. The preferred particle size of the coal was set to 1 mm or less in consideration of both the ability to remove metal compounds and the like and the economic efficiency.

The coal used in the present invention may contain water. In general, low-grade coal containing many polar groups is hydrophilic, and therefore usually contains a large amount of water. For example, in the case of Australian lignite, about 60% by weight is moisture.

However, when the coal contains water, the presence of water makes it impossible to efficiently remove the desired metal components and the like. For example, in the case of the above-mentioned Australian lignite, most of its surface is covered with water, so when a slurry is prepared by mixing the lignite and waste oil, a carboxyl group, a phenol group, a carbonyl group present on the lignite surface It is thought that the area in which the polar group such as is in contact with the waste oil is not so large, and thus the desired chemical adsorption reaction does not proceed smoothly. In addition, since water generally has a very high polarity and easily forms a hydrogen bond with a polar group in brown coal, it is conceivable that a polar compound in waste oil is prevented from adsorbing on brown coal.

It is feared that the presence of water in this way would eventually inhibit the chemical adsorption reaction intended in the present invention, but according to the method of the present invention, waste oil and coal There is no particular problem because the raw material slurry obtained by mixing is heated to remove the moisture in the coal (in-oil dehydration method). That is, a mixed waste oil containing a waste oil containing impurities such as metal components and a purified oil (corresponding to the waste oil used in the present invention)
And, if a method of mixing hydrated coal into a slurry state and heating it to, for example, 100 to 250 ° C. is adopted, moisture in the pores is vaporized and evaporated by the heating and diffused. Polar compounds containing a metal component and a halogen component such as chlorine can be selectively chemically adsorbed. In consideration of avoiding thermal decomposition of coal by heating, it is recommended that the heating temperature be 100 to 150 ° C. In this way, the mixed waste oil adheres as the vaporization and evaporation of the water in the pores proceeds, and even if there is some residual water vapor, the water vapor condenses due to cooling during the handling process after dehydration in oil. When a negative pressure is formed in the pores and the mixture is sucked into the pores, the mixed waste oil containing a metal component and a halogen component is deeply adsorbed to the deep portion inside the pores. It becomes like. It is considered that the metal component and the halogen component in the lignite can be efficiently chemically adsorbed to the oil to be treated through the above-mentioned process during the dehydration in oil.

The coal used in the present invention covers all porous coals such as lignite and subbituminous coal in addition to the above-mentioned lignite, and is not particularly limited as long as it has a polar group. Further, as the brown coal, there are Victoria coal, North Dakota coal, Berga coal, and the like, and any porous coal containing a polar group is an object of the present invention regardless of the place of production.

The source and properties of the waste oil to which the present invention is applied are not specified as long as they contain a metal compound or an organic halogen compound derived from the above-mentioned additives. These are: vehicle lubricants, aircraft lubricants, marine lubricants, industrial lubricants,
Specially-used waste oils such as metal processing waste oil, rust prevention waste oil, electrical insulation waste oil, etc., natural lubricant oils such as spindle waste oil, machine waste oil and other natural lubricants, and synthetic lubricants.

In the method of the present invention, such a waste oil and coal (coal may contain moisture) are mixed to obtain a raw slurry, and a treated slurry obtained by heating this raw slurry is obtained. Is subjected to solid-liquid separation to remove coal and obtain a refined oil. In the present invention, while such a refined oil is obtained, if moisture is contained in the coal, it is dehydrated, and selectively adsorbs metal components and the like in the waste oil, and can be recovered as a by-product. It is also possible to reuse for example.

In the present invention, it is recommended to heat the waste oil at a temperature of 150 to 400 ° C. before mixing the coal. Metals (such as Zn) contained in additive components such as dithiophosphate and dithiocarbamate, and chlorine contained in additive components such as P and chlorinated paraffin can be sufficiently removed only by treatment by physical adsorption and chemical adsorption. This is because it is difficult, and by changing its form by thermal decomposition, the removal rate of the above components is remarkably improved. Therefore, when the waste oil is subjected to heat treatment before mixing the coal (heat treatment + dehydration treatment in oil), Zn, P, chlorine, etc. are compared with the case where only the dehydration treatment in oil is performed without heat treatment. Will be improved.

For example, additive components (such as dithiophosphate and dithiocarbamate) containing Zn and P are thermally decomposed by heat treatment before mixing, and zinc sulfide (zinc ore or wurtzite) or phosphate (Ca, Zn). Etc.), and phosphorus sulfide and the like. Since these compounds are insoluble in oil, they precipitate as solids after the heat treatment. Of these, wurtzite and phosphates have low solubility not only in oil but also in water.Therefore, they remain in a solid state in the oil dehydration step performed after the heat treatment, and are filtered out together with the waste coal in the centrifugation step. Will be.

Some of the water-soluble substances such as sphalerite are dissolved in water existing in the pores of coal at the slurry preparation stage of the in-oil dehydration step performed after the heat treatment. It is thought that this dissolved component is taken into the coal in the form of a solid precipitated in the coal pores as the water evaporates, and is then filtered out together with the waste coal in the centrifugation process. It is presumed that.

In the present invention, the waste oil is heat-treated at a temperature in the range of 150 to 400 ° C., whereby the efficiency of removing Zn and P can be significantly increased. More preferably, it is 150 ° C. or more and 250 ° C. or less. The additive containing Zn and P is 1
This is because it is considered to decompose at about 50 to 250 ° C.

On the other hand, the reason why the chlorine removal rate was improved by the heat treatment of the waste oil is considered that additive components such as chlorinated paraffin were thermally decomposed by the heat treatment and were discharged out of the system as hydrogen chloride gas. . Further, it is considered that some chlorine reacts with Ca and Ma in the waste oil to form calcium chloride and magnesium chloride. These compounds have low solubility in oil, and thus precipitate as a solid after heat treatment. it seems to do.

Since calcium chloride and magnesium chloride are soluble in water, a part of them is dissolved in water existing in the pores of coal at the slurry preparation stage of the in-oil dehydration step performed after the heat treatment. It is thought that this dissolved component is taken into the coal in the form of a solid precipitated in the coal pores as the water evaporates, and is then filtered out together with the waste coal in the centrifugation process. It is presumed that. On the other hand, those not dissolved in water are filtered off together with the waste coal.

FIG. 5, which will be described later, is a graph of the result of examining the effect of the heat treatment temperature of the waste oil on the dechlorination rate. In consideration of the result shown in FIG. 5, chlorine in the waste oil is reduced. To remove, the heating temperature should be at least 200
It is necessary to raise the temperature to at least ℃, and it is understood that the higher the heating temperature, the higher the dechlorination rate. However, if the heating temperature is 2
In the vicinity of 90 to 300 ° C., even if the temperature is further increased, the effect of increasing the dechlorination rate tends to be saturated, but rather, only the energy consumption by heating increases.
It is also said that waste oil generally starts to decompose at 400 ° C. or higher.

Therefore, in order to improve the efficiency of removing chlorine from the waste oil, it is necessary to consider both the chlorine removal rate and the energy consumption required for heating. The heat treatment is preferably performed at a temperature of 400 ° C. or lower and 400 ° C. or lower. More preferably 270 ° C or higher 3
50 ° C. or less.

After heating the waste oil at the above temperature,
It is recommended that the raw material slurry obtained by mixing with the coal in the same manner as described above and heating at 100 to 150 ° C. is recommended.

Further, in the present invention, for the purpose of effectively suppressing the generation of hydrogen halide during the heat treatment,
It is recommended to use waste oil that satisfies the following formula.

[Halogen] / {[Ca] + [Mg] + [Ba]} ≦ 2 In the formula, [] indicates an atomic mole of each element contained in the waste oil.

This is because, in the case where a halogen-containing substance such as chlorine is directly heated, there is a possibility that a hydrogen treatment gas such as hydrogen chloride gas generated by thermal decomposition may cause deterioration of the heat treatment apparatus. By controlling the total amount of Ca, Mg, and Ba in proportion to the amount of halogen atoms, the amount of generated hydrogen halide gas is suppressed. The use of waste oil that satisfies the above formula is extremely effective in that the generation of hydrogen halide gas such as hydrogen chloride gas can be significantly suppressed, and the life of the device can be extended. Further, when recovering hydrogen chloride gas or the like, it is usually trapped with water and recovered as hydrochloric acid. However, a large amount of alkali is required to neutralize and process the recovered hydrochloric acid. According to the present invention, since the amount of generated hydrogen chloride gas is significantly suppressed, it is also useful in that the amount of alkali required for the neutralization treatment can be significantly reduced.

FIG. 1 shows an example of a waste oil heat treatment apparatus used in the present invention. The waste oil is heated by a heater while checking the temperature with a thermometer. The hydrogen chloride gas generated by the heating is collected in a receiver through a cooling pipe while being cooled by cooling water. The recovered hydrochloric acid may be neutralized with an alkali via a backflow prevention cushion.

Hereinafter, chlorine, which is a typical example of halogen, will be described with respect to the hydrogen halide to be removed in the above-described embodiment, but the present invention is not limited thereto.

In general, chlorine is used as an additive for extreme pressure agents in the form of paraffin chloride or chloronaphthazanthate. When these compounds are heat-treated, they are thermally decomposed to generate hydrogen chloride gas.

On the other hand, Ca, Mg and Ba are Me (OH) ₂
And in the form of MeCO ₃ (a metal of Me = Ca, Mg, Ba) having a micellar structure with a metal sulfonate or a metal phenolate, and such a compound is widely used as a detergent and dispersant.

The present invention relates to Ca, M represented by the above Me.
It is intended to trap hydrogen chloride gas which has an adverse effect on a heat treatment apparatus or the like using g and Ba. That is,
Me (C) contained in the above Me (OH) ₂ and MeCO ₃
a, Mg, Ba) is by generating MEC1 ₂ reacts with hydrogen chloride gas generated by heat treatment, is that attempts to reduce generation of hydrogen chloride gas.

In order to effectively exert the above-mentioned action by Ca, Mg, and Ba, the atomic mole of chlorine (hereinafter referred to as [Cl]) with respect to the total atomic mole of Ca, Mg and Ba (hereinafter abbreviated as [Ca + Mg + Ba]). Abbreviated as 2)
Or less (= 2 equivalents or less; that is, [Ca
+ Mg + Ba] is required to be at least 2 atomic moles, and if [Cl] is excessive with respect to [Ca + Mg + Ba], the excess chlorine is generated as a hydrogen chloride gas. It is recommended that

It should be noted that the chlorine-based additive is used only in a part of the cutting oil and the like, and when viewed from the whole waste oil, it is contained in only a part of the oil, whereas Ca, Mg, Ba In view of the fact that the additive containing is contained in a very large number of lubricating oils as a detergent and dispersant, for waste oil having a high chlorine content, Ca, Mg, A waste oil containing a large amount of Ba may be mixed, diluted and used.
In this case, since [Ca + Mg + Ba] is larger than [Cl], there is no possibility that excess chlorine is generated as hydrogen chloride gas. Alternatively, Me (OH) _{2 is} added to chlorine-containing waste oil.
Alternatively, MeCO ₃ may be directly added.

In the practice of the present invention, a part of the purified waste oil obtained by subjecting the treated slurry to solid-liquid separation can be circulated and used as a medium for forming a raw material. Further, water vapor generated by heating the raw material slurry may be collected and subjected to gas-liquid separation, and the gas phase may be pressurized and used as a heating source for the raw material slurry.

In the present invention, coal / waste oil (hereinafter abbreviated as coal waste oil ratio) refers to the amount of polar groups in the coal used, the recovered amount of dehydrated coal as a by-product, and the amount of recycled waste oil (the amount of refined oil produced).
It is recommended to use 1 to 1/100, preferably 1/4 to 1/50, and more preferably 1/10 to 1/20, on an anhydrous carbon basis, from the viewpoint of the economic balance. At a practical level, when the content of metal compounds and organic halogen compounds in the waste oil is high, it may be necessary to use a high coal waste oil ratio, but there is also a problem that the recovery rate of the recycled waste oil decreases; On the other hand, when the content of metal compounds and organic halogen compounds in the waste oil is low, it should be noted that excellent removal effect can be obtained even if the coal waste oil ratio is low. Is desirable.

It is recommended that the slurry be heated until the water content in the coal becomes 10% by weight or less. If the in-oil treatment is terminated in a state where the water content is high, the amounts of metal components and halogen components to be adsorbed on the coal also decrease, and therefore the amounts of these components contained in the reclaimed waste oil increase, This is because the quality of the recycled waste oil is reduced.

In carrying out the method of the present invention, for example, a purification apparatus shown in FIG. 2 can be used. This refining device basically comprises a mixing tank for mixing waste oil and coal to form a raw material slurry, a preheater for preheating the raw material slurry, and an evaporator for heating the preheated raw material slurry to remove water vapor. And a solid-liquid separator for solid-liquid separation of the heated treated slurry, wherein the solid-liquid separator includes a sedimentation tank, a centrifugal separator, a filter, a press, or a combination thereof. Can be used. In addition, this device includes:
It is also possible to add a dryer for drying the solids separated by solid-liquid separation. In Figure 2, A slurry dewatering section, A ₁ is a mixture, A2 evaporation unit, B is the solid-liquid separation unit, C is the final drying section,
1 is a mixing tank, 2 and 6 are pumps, 3 and 4 are preheaters, 5
Is a gas-liquid separator, 7 is an evaporator, 8 is a compressor, 9 is a waste oil / water separator, 10 is a centrifugal separator, 11 is a screw press, 1
2 indicates a dryer, 13 indicates a condenser, 14 indicates a pump, 15 indicates a cooler, and 16 indicates a heater. This refining apparatus is a reappearance of the apparatus described in JP-A-7-233376, and the method for purifying waste oil using this apparatus may be referred to the method described in the publication.

Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention, and all changes and implementations without departing from the spirit of the preceding and the following are included in the technical scope of the present invention.

[0060]

Examples <Examples 1 to 5 and Comparative Examples 1 and 2>
Table 2 shows the properties of the waste oils (A and B) used in Examples 1 to 5 and Comparative Examples 1 and 2, and the properties of the coals (a and b) used in these Examples and Comparative Examples, respectively. . Unless otherwise specified, “%” means “% by weight”.

[0061]

[Table 1]

[0062]

[Table 2]

Example 1 A raw material slurry was prepared by mixing 100 parts of waste lubricating oil A and 12 parts of coal a (5 parts of anhydrous coal and 7 parts of water, and hence a water content of 58%). The obtained raw material slurry is heated to 140
As a result of dehydration in oil at 1 ° C. and 1 atm, 6 parts of water were removed. The treated slurry was subjected to centrifugal separation to perform solid-liquid separation, thereby recovering 88 parts of recycled lubricating oil and 18 parts of treated coal.

C in the regenerated lubricating oil thus obtained
Table 3 shows the results of measuring the concentrations of a, Zn, Fe, Mg, P and Cl.

[0065]

[Table 3]

From Table 3, the recovery rate of the regenerated lubricating oil in Example 1 was as high as 88%. Looking at the removal rate of each component in the waste lubricating oil A, Ca was 80%,
91% of Zn, 65% of Mg, and 79% or more of Cl are adsorbed and removed by coal, and the concentration in the regenerated lubricating oil is C
a: 360 ppm, Zn: 90 ppm, Mg: 70 pp
m, Cl: 30 ppm or less.

Example 2 In Example 1, the amount of coal a was changed to 24 parts (anhydrous coal 10
Parts and 14 parts of water, therefore, the water content was 58%). As a result, 13 parts of water were removed. When the treated slurry was subjected to centrifugation to perform solid-liquid separation, 84 parts of recycled lubricating oil and 27 parts of treated coal were recovered.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 3.

The recovery rate of the regenerated lubricating oil in Example 2 was 8
The removal rate of each component in the waste lubricating oil A was as high as 4%, and it was found that Ca was 92%, Zn was 95% or more, Fe was 65%, Mg was 75% or more, and Cl was 79%. % Or more is adsorbed and removed by the coal, and the concentration in the regenerated lubricating oil is 140 ppm for Ca, 50 ppm or less for Zn,
e: 70 ppm, Mg: 70 ppm or less, Cl: 30 p
pm or less.

Example 3 The procedure of Example 2 was repeated, except that the waste lubricating oil A was replaced by a waste oil B having a higher Ca and Zn content than the waste lubricating oil A. As a result, 13 parts of water was removed. When the treated slurry was subjected to centrifugal separation to solid-liquid separation, 83 parts of regenerated lubricating oil, treated coal 28
Parts were collected.

The Ca in the reclaimed lubricating oil thus obtained was
, Etc., and the results are also shown in Table 3.

The recovery rate of the regenerated lubricating oil in Example 3 was 8
3%, the removal rate of each component in the waste lubricating oil B is 93% for Ca, 85% for Zn,
At least 72% of Fe, at least 58% of Mg, and at least 73% of Cl are adsorbed and removed by the coal. The concentrations in the regenerated lubricating oil are 410 ppm Ca, 180 ppm Zn, and 180 ppm F, respectively.
e: 50 ppm or less, Mg: 50 ppm or less, Cl: 3
It became 0 ppm or less.

Example 4 In Example 3, the amount of coal a was changed to 48 parts (anhydrous coal 20
And the water content was 58%, so that the same treatment as in Example 3 was carried out, except that 26 parts of water was removed. When this treated slurry was subjected to centrifugal separation to separate into solid and liquid, 66 parts of recycled lubricating oil and 56 parts of treated coal were recovered.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 3.

The recovery rate of the regenerated lubricating oil in Example 4 was 6
6%, the removal rate of each component in waste lubricating oil B is 97% for Ca, 96% or more for Zn, and
e is 72% or more, Mg is 58% or more, and Cl is 73% or more is adsorbed and removed by the coal. The concentrations in the regenerated lubricating oil are Ca: 160 ppm, Zn: 50 ppm and F, respectively.
e: 50 ppm or less, Mg: 50 ppm or less, Cl: 3
It became 0 ppm or less.

Example 5 100 parts of waste lubricating oil B and 14 parts of coal b (anhydrous coal 1
0 part, 4 parts of water, and a water content of 27%) were mixed to prepare a raw material slurry. The obtained raw material slurry is heated to 140
As a result of dehydration in oil at 1 ° C. and 1 atm, 4 parts of water were removed. When this treated slurry was subjected to centrifugal separation to be subjected to solid-liquid separation, 86 parts of recycled lubricating oil and 24 parts of treated coal were recovered.

The Ca in the regenerated lubricating oil thus obtained is
, Etc., and the results are also shown in Table 3.

The recovery rate of the regenerated lubricating oil in Example 5 was 8
6%, the removal rate of each component in waste lubricating oil B is 92% for Ca, 84% for Zn,
61% of Fe, 50% of Mg, and 45% of Cl are adsorbed and removed from coal, and the concentrations in the regenerated lubricating oil are Ca:
490 ppm, Zn: 190 ppm, Fe: 70 pp
m, Mg: 60 ppm and Cl: 60 ppm.

Comparative Example 1 100 parts of waste lubricating oil B and activated clay 1 having no polar group
0 parts were mixed to prepare a raw material slurry. The obtained raw material slurry was heated and stirred at 140 ° C. and 1 atm. This treated slurry is centrifuged to separate into solid and liquid, whereby 85 parts of regenerated lubricating oil, treated clay 2
Five parts were collected.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 3.

The recovery rate of the regenerated lubricating oil in Comparative Example 1 was 8
Although it was as high as 5%, when looking at the removal ratio of each component in the waste lubricating oil B, Ca was 66%, Fe was 17%, and M
g is only 42% and Cl is only 27% adsorbed and removed from the coal. The concentration in the regenerated lubricating oil is Ca: 2100 pp, respectively.
m, Fe: 150 ppm, Mg: 70 ppm, Cl: 8
It was 0 ppm.

Comparative Example 2 100 parts of waste lubricating oil B and 24 parts of coal a (anhydrous coal 1
0 parts and 14 parts of water, and hence a water content of 58%) were mixed to prepare a raw material slurry. The obtained raw material slurry was stirred at room temperature and treated in oil. When the treated slurry was subjected to centrifugal separation to separate into solid and liquid, the regenerated lubricating oil 85
And 39 parts of treated coal.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 3.

The recovery rate of the regenerated lubricating oil in Comparative Example 2 was 8
Although it was as high as 5%, looking at the removal ratio of each component in the waste lubricating oil B, Ca was 49%, Fe was 6%, Mg was 49%.
Was adsorbed and removed on coal only 25%, and no Cl was removed. Also, the concentration in the regenerated lubricating oil
Ca: 3100 ppm, Fe: 170 ppm, Mg: 9
0 ppm and Cl: 110 ppm.

The above results are comprehensively considered as follows. That is, in the case of using any of A and B having different contents of metal and chlorine as waste oil, dehydration treatment in oil is performed using coal containing a predetermined amount of polar groups such as carboxyl group, phenol group and carbonyl group (Examples). 1 to 5), the Ca and Zn derived from the additives are compared with the case where the coal is stirred at room temperature (Comparative Example 2) and the case where the coal is subjected to a high-temperature stirring treatment with clay having no polar group (Comparative Example 1). , M
It was found that metals such as g and P and chlorine were adsorbed and removed at a high level, and that waste oil could be purified to a high concentration.

FIG. 3 is a graph plotting the addition amount of coal on the horizontal axis and the recovery rate of the regenerated lubricating oil on the vertical axis based on the above results. From the figure, the recovery rate of regenerated lubricating oil is
It can be seen that when the amount of coal used increases, the amount decreases, and when the recovery rate of the regenerated lubricating oil is to be maintained at 85% or more, the amount of coal used is 10% or less with respect to the oil to be treated.

When the amount of coal added is 10%, polar groups (carboxyl group, carboxyl group,
FIG. 4 shows the relationship between the oxygen concentration of the phenol group and the carbonyl group) and the Ca removal rate. From FIG. 4 and Table 3, as the amount of the polar group in the coal increases, the amount of Ca, Z
It can be seen that the effect of removing metals such as n, Mg, and P and chlorine is increased. Here, a recovery rate of the regenerated lubricating oil of about 85% is secured, and the highest content of C among the added components is obtained.
It can be seen that in order to ensure a removal rate of a of 90% or more, it is necessary to use coal in which the content of oxygen contained in the polar group is 15% or more.

In addition, coal a having more polar groups than coal b
Even in the case of using oil, if the result of Comparative Example 2 that the effect of removing metals such as Ca, Zn, Mg, and P and chlorine is lowered when stirring at room temperature without dehydration in oil is considered, It has been confirmed that the treatment by middle dehydration is extremely useful in remarkably enhancing the metal / chlorine adsorption effect on coal. <Examples 6 to 10> Table 4 shows properties of the waste oils (CF) used in Examples 6 to 10 below. In addition, the same coal as a shown in Table 2 was used as the coal used in the above examples.

[0089]

[Table 4]

Example 6 100 parts of waste lubricating oil C and 24 parts of coal a (anhydrous coal 10
Parts and 14 parts of water, therefore, the water content was 58%) to prepare a raw material slurry. The obtained raw material slurry is heated and
As a result of performing dehydration in oil at 40 ° C. and 1 atm, 13 parts of water was removed. This treated slurry was subjected to centrifugal separation to separate into solid and liquid, thereby recovering 85 parts of recycled lubricating oil and 26 parts of treated coal.

C in the regenerated lubricating oil thus obtained
Table 5 shows the results of measuring the concentrations of a, Zn, Fe, Mg, P, Cl and Ba.

[0092]

[Table 5]

As shown in Table 5, the recovery of the regenerated lubricating oil in Example 6 was as high as 85%. Looking at the removal ratio of each component in the waste lubricating oil C, Ca was 96%,
89% Zn, 86% Fe, more than 67% Mg, 3% P
7% and 3% of Cl are adsorbed on coal, respectively. The concentrations in the regenerated lubricating oil are Ca: 80 ppm and Zn: 70 p, respectively.
pm, Fe: 10 ppm, Mg: less than 10 ppm, P:
330 ppm, Cl: 19500 ppm.

Example 7 Using the heat treatment apparatus shown in FIG.
5 parts) to 400 ° C (heating rate: about 1 ° C / m)
as a result, water 2 parts, hydrogen chloride gas 2 parts, distillate 1
And 100 parts of the remaining oil in the kettle were recovered. FIG. 5 shows the relationship between the heat treatment temperature of the waste lubricating oil and the dechlorination rate in the lubricating oil. From the figure, chlorine starts to decompose at a heating temperature of about 200 ° C., and at about 250 ° C., about 20 w
About 53 wt% at 270 ° C., about 75 wt% at 300 ° C., and about 77.8 wt% at 350 ° C. decompose to generate hydrogen chloride gas. The amount increased little.

Further, the procedure of Example 6 was repeated except that 100 parts of the residual oil in the kettle subjected to the heat treatment as described above was used.
As a result of the dehydration treatment in oil in the same manner as described above, 13 parts of water was removed. The treated slurry was subjected to centrifugal separation to perform solid-liquid separation, thereby recovering 87 parts of recycled lubricating oil and 24 parts of treated coal.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 5.

As shown in Table 5, the recovery rate of the regenerated lubricating oil in Example 7 (the sum of the recovery rates in both the heat treatment and the coal treatment) was as high as 82%. Looking at the removal rate of each component in the waste lubricating oil C, Ca was 9%.
4%, Zn is more than 99%, Fe is more than 86%, Mg is 67%
Ultra, P is over 98%, Cl is 99% removed, and the concentrations in the reclaimed lubricating oil are Ca: 110 ppm and Zn:
Less than 10 ppm, Fe: less than 10 ppm, Mg: 10p
pm, P: less than 10 ppm, Cl: 230 ppm.

A comparison between the above-described Examples 6 and 7 shows that in Example 6 in which only the dehydration treatment in oil was performed, the Zn removal rate was 89% and the P removal rate was not so high at 37%. And the removal rate of chlorine was as extremely low as 3%, whereas the heat treatment was carried out before the dehydration treatment in oil.
In the oil dehydration treatment), the Zn removal rate exceeds 99%, and P
It was also confirmed that the removal rate of methane exceeded 98% and the removal rate of chlorine was dramatically improved to 99%.

Example 8 The result of performing heat treatment in the same manner as in Example 7 except that 103.5 parts of waste lubricating oil D was used and the temperature of the heat treatment was set to 350 ° C. , Water 2
Parts, 0.5 parts of hydrogen chloride gas, 1 part of distillate oil, residual oil in kettle 10
0 parts were recovered. Further, 57.1% of chlorine in the waste lubricating oil was generated as chlorine hydrogen gas by the heat treatment up to 350 ° C.

Next, in Example 7, a dehydration treatment in oil was carried out in the same manner as in Example 7, except that 100 parts of the residual oil in the kettle obtained by the heat treatment in Example 8 was used.
Three parts were removed. The treated slurry was subjected to centrifugal separation to separate into solid and liquid, thereby recovering 85 parts of recycled lubricating oil and 26 parts of treated coal.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 5.

As shown in Table 5, the recovery rate of the regenerated lubricating oil in Example 8 was as high as 82%. Looking at the removal ratio of each component in the waste lubricating oil D, Ca was 95%,
Zn exceeds 99%, Fe exceeds 86%, Mg exceeds 67%, P
Is more than 98% and Cl is 98% removed. The concentrations in the regenerated lubricating oil are Ca: 100 ppm and Zn: 10 p, respectively.
pm, Fe: less than 10 ppm, Mg: less than 10 ppm, P: less than 10 ppm, Cl: 120 ppm.

Example 9 A heat treatment was performed in the same manner as in Example 8 except that 103 parts of waste lubricating oil E was used. As a result, 2 parts of water, 1 part of distillate oil, and the residue in the kettle were obtained. 100 parts of oil were recovered. Further, by performing the heat treatment to 350 ° C., 21.3% of chlorine in the waste lubricating oil was generated as hydrogen chloride gas.

Next, in Example 8, the dehydration treatment in oil was carried out in the same manner as in Example 8 except that 100 parts of the residual oil in the kettle obtained by the heat treatment in Example 9 was used. Removed. The treated slurry was centrifuged to separate into solid and liquid, thereby recovering 86 parts of recycled lubricating oil and 25 parts of treated coal.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 5.

The recovery rate of the regenerated lubricating oil in Example 9 was 8
It was extremely high at 3%. Looking at the removal ratio of each component in the waste lubricating oil, Ca was 95% and Zn was 99%.
Over, Fe over 86%, Mg over 67%, P over 98%,
96% of Cl has been removed, and the concentrations in the regenerated lubricating oil are Ca: 90 ppm, Zn: less than 10 ppm, and F, respectively.
e: less than 10 ppm, Mg: less than 10 ppm, P: 10
ppm, Cl: 60 ppm.

Example 10 A heat treatment was carried out in the same manner as in Example 8 except that 103 parts of waste lubricating oil F was used. As a result, 2 parts of water, 1 part of distillate oil, 100 parts of oil were recovered. In addition, by performing the heat treatment to 350 ° C., 14.2% of chlorine in the waste lubricating oil was generated as chlorine hydrogen gas.

Next, in the eighth embodiment, the tenth embodiment will be described.
As a result of dehydration treatment in oil in the same manner as in Example 8 except that 100 parts of residual oil in the kettle obtained by the heat treatment of
Parts have been removed. The treated slurry was subjected to centrifugal separation to perform solid-liquid separation, thereby recovering 88 parts of recycled lubricating oil and 23 parts of treated coal.

The Ca in the regenerated lubricating oil thus obtained was
, Etc., and the results are also shown in Table 5.

The recovery rate of the regenerated lubricating oil in Example 10 was as high as 85%. Looking at the removal ratio of each component in the waste lubricating oil E, Ca was 95% and Zn was 9%.
Over 9%, Fe over 86%, Mg over 67%, P over 98%
Super and Cl are removed by 85%, and the concentrations in the regenerated lubricating oil are respectively 110 ppm for Ca, 10 ppm or less for Zn, 10 ppm or less for Fe, 10 ppm or less for Mg,
P: 10 ppm or less, Cl: 30 ppm.

FIG. 6 is a graph showing the relationship between the ratio of [Cl] to [Ca + Mg + Ba] in the waste oil, the chlorine removal rate, and the amount of hydrogen chloride gas generated by the heat treatment. In the figure, ■ indicates the total chlorine removal rate, and ● indicates the amount of hydrogen chloride gas generated.

[0112] From the figure, the total chlorine removal rate was determined by [C
a + Mg + Ba], which is very good at about 80% or more regardless of the ratio of [Cl] to [Ca + Mg + Ba].
In the case where the ratio of [Cl] to [Mg + Ba] exceeds 2, [Example 7 (the above ratio 11.55) and Example 8 (the above ratio 4.33)], the amount of hydrogen chloride gas generated by the heat treatment is remarkable. From the rise, it can be seen that, of the chlorine removed in both the heat treatment and the dehydration in oil steps, the proportion of chlorine removed as hydrogen chloride gas by the heat treatment is high.

On the other hand, [Ca + Mg + B
When the ratio of [Cl] to [a] is 2 or less [Example 9]
(The above ratio 1.97) and Example 10 (the above ratio 0.1
In 1)], the amount of hydrogen chloride gas generated by the heat treatment is remarkably reduced, which indicates that the ratio of chlorine removed by the dehydration treatment in oil is increased.

Therefore, it is apparent that the use of waste oil that satisfies the above formula can significantly suppress the ratio of chlorine removed as hydrogen chloride gas by heat treatment while maintaining a high chlorine removal rate. became.

[0115]

Industrial Applicability The present invention is constituted as described above. By subjecting waste oil to dehydration treatment in oil using coal containing a polar group, not only physical adsorption removal in a conventional oil refining method but also waste oil As a result of being able to selectively chemically adsorb the metal components and chlorine components in the polar groups in the coal, it has become possible to purify waste oil economically and efficiently.

Before mixing the coal, the waste oil is
By heating at a temperature of 400 ° C., the refining efficiency is remarkably improved, and if the ratio of each component present in the waste oil satisfies the above formula, the generation of hydrogen halide is significantly suppressed. It is very useful.

Further, according to the present invention, while a desired refined lubricating oil is obtained, the raw material coal is dewatered as required, and thus can be recovered as high quality porous coal for solid fuel.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a heat treatment apparatus used for heating waste oil.

FIG. 2 is a diagram showing an outline of a manufacturing apparatus that can adopt the method of the present invention.

FIG. 3 is a graph showing the relationship between the amount of coal added and the recovery rate of regenerated lubricating oil.

FIG. 4 is a graph showing a relationship between an oxygen concentration in an oxygen-containing polar group contained in coal and a Ca removal rate.

FIG. 5 is a graph showing the relationship between the waste oil heat treatment temperature and the dechlorination rate.

FIG. 6 shows [C + Mg + Ba] in waste oil
1] is a graph showing the relationship between the ratio [1] and the total chlorine removal rate / the amount of hydrogen chloride gas generated in the heat treatment.

[Explanation of symbols]

A Slurry dewatering section A ₁ mixture A ₂ Evaporation section B Solid-liquid separation section C Final drying section 1 Mixing tank 2, 6 Pump 4 Preheater 5 Gas-liquid separator 7 Evaporator 8 Compressor 9 Waste oil water separator 10 Centrifuge 11 Screw press 12 Dryer 13 Condenser 14 Pump 15 Cooler 16 Heater

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Exit 1-5-5 Takatsukadai, Nishi-ku, Kobe City Inside Kobe Research Institute, Kobe Steel Ltd. 5-5-5 Kobe Steel, Ltd.Kobe Research Institute

Claims (5)

[Claims] A raw material slurry is obtained by mixing waste oil containing a metal compound and / or an organic halogen compound and coal,
A method for refining waste oil, comprising heating the raw material slurry to adsorb metal compounds and / or organic halogen compounds in the waste oil onto coal, thereby refining the waste oil. 2. The method for purifying waste oil according to claim 1, wherein the metal compound and / or the organic halogen compound in the waste oil is adsorbed by the polar group in the coal. 3. The method for refining waste oil according to claim 2, wherein the amount of the polar group is 15% by weight or more in terms of the total oxygen content of the carboxyl group, the hydroxyl group and the carbonyl group based on the coal excluding moisture and ash. . 4. The method according to claim 1, wherein the waste oil is mixed with coal before mixing.
The method for refining waste oil according to any one of claims 1 to 3, wherein the heating is performed at a temperature of 400C to 400C. 5. The method according to claim 1, wherein the generation of hydrogen halide is suppressed by using a waste oil satisfying the following expression.
5. The method for refining waste oil according to any one of claims 1 to 4. [Halogen] / {[Ca] + [Mg] + [Ba]} ≦ 2 In the formula, [] indicates the atomic mole of each element contained in the waste oil.