JP2006249419A - Method of regenerating treatment for waste oil, and agent for regeneration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agent for regeneration which causes no or little emulsion, and to provide a method for regenerating an oil from a waste oil by using such an agent for regeneration. <P>SOLUTION: The method for recovering an oil being freed of ash comprises the addition of urea to a waste oil, agitation, still standing, then the separation of an oil component. The method for recovering an oil being freed of ash comprises the addition of ammonium nitrate and a chelating agent to an ash-containing waste oil, agitation, still standing and then the separation of the oil component. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of removing ash and recovering oil from waste oil (emulsion) containing ash such as used engine oil and used industrial lubricating oil. Furthermore, this invention relates to the waste oil reproduction | regeneration processing agent which can collect | recover high quality oil from these waste oils.

  In recent years, from the viewpoints of effective use of resources and environmental conservation, proper disposal of waste, promotion of recycling, etc. have been taken up as social urgent issues. In response to these issues, the establishment of the Waste Management Law, Recycling Law, Energy Saving / Recycling Support Law, Containers and Packaging Recycling Law, etc. has been steadily proceeding from the legal aspect. There is also a need to develop a recycling technology that can reduce the amount of waste and recycle the waste so that it can be used as effectively as possible. In particular, for example, many of the waste oils that are difficult to reuse, such as used engine oils and industrial lubricating oils, have been incinerated. Moreover, since there is a possibility that the metal content in the waste oil may act as a catalyst for the generation of dioxins, a technique for removing it has been desired.

  Conventionally, in waste oil treatment of lubricating oil such as engine oil, sulfuric acid treatment and clay treatment are generally performed. As the treatment method, for example, water in waste oil and floating dust are removed by pretreatment, concentrated sulfuric acid is added and the mixture is allowed to stand, and then the sulfuric acid sludge is separated by centrifugation. Add the white clay to the remaining waste oil in the acidic state and neutralize it by heat treatment, then remove the light oil by vacuum distillation and filter the waste white clay. The method of obtaining is mentioned. However, the above-mentioned conventional methods may cause secondary pollution due to sulfuric acid sludge and waste clay, and the activated clay is expensive and ash content that is required to be reduced to a certain level or less as recycled heavy oil, especially for reuse. There is a problem that (metal content) cannot be reduced sufficiently.

  As other treatment methods, for example, solvent extraction and hydrorefining treatment methods are also known, but none of them has been implemented due to high cost of recycled oil. Furthermore, although there is a report that a waste oil regeneration technology using bituminous coal is being developed, it is not economical and not put into practical use because the plant becomes huge.

  Normal engine oils contain many metal additives such as metal detergents, zinc dithiophosphate, and organic molybdenum compounds to enhance engine cleanability, antioxidant performance, and wear prevention performance. Waste oil that contains a lot of ash contains a lot of ash. Accordingly, recycled heavy oil obtained from waste oil containing a large amount of used engine oil by a conventional processing method cannot be used as a fuel for boilers or internal combustion engines because much ash remains. In particular, waste oil including used diesel engine oil containing very fine soot (fine particles called diesel particulates having a particle size of 20 to 30 nm) is not sufficient in a method using a normal filter or a conventional regeneration treatment method. Therefore, the recycled heavy oil is not effectively used.

  In general, waste oil of industrial lubricating oil contains impurities of very fine particle size containing salts and alkalis, and by-products that can be deteriorated by use include hydroxyl groups or ether groups such as water and Since it contains an organic substance having a functional group with high affinity, impurities could not be completely removed by solid-liquid separation such as sedimentation separation, centrifugation, and filtration separation.

Sodium silicate is used as a regenerative treatment agent to efficiently and easily remove and reduce impurities such as ash (metal) in waste oil containing a lot of engine oil to obtain a higher quality reclaimed oil. Have been proposed (Japanese Patent Laid-Open No. 2003-176492, Patent Document 1).
JP 2003-176492 A

  By using sodium silicate described in Patent Document 1 as a regeneration treatment agent, impurities contained in the waste oil can be efficiently removed easily and inexpensively, and a high-quality reclaimed oil can be obtained. In this treatment method, sodium silicate is used as an aqueous solution, and the aqueous solution and waste oil are stirred and mixed to transfer impurities in the waste oil to the aqueous phase. However, after stirring and mixing the aqueous solution and waste oil, an emulsion phase is formed between the oil phase and the aqueous phase, and the emulsion does not disappear even if the standing time is prolonged. The problem is newly revealed. The remaining emulsion needs to be subjected to a new process.

  Therefore, the present invention has an object to provide a regenerative treatment agent that does not cause the emulsion as described above, and is difficult to produce, and a method for recovering oil from waste oil using such a regenerative treatment agent. .

The present invention for solving the above problems is as follows.
[1] A method for recovering oil from which ash has been removed, including adding urea to waste oil, stirring and allowing to stand, and then separating the oil.
[2] The method according to [1], wherein 0.001 to 0.1 M urea aqueous solution is added in a range of 0.1 to 20 times by mass with respect to the waste oil.
[3] A method for recovering oil from which ash has been removed, comprising adding ammonium nitrate and a chelating agent to waste oil containing ash, stirring and allowing to stand, and then separating the oil.
[4] The method according to [3], wherein an aqueous solution containing 0.001 to 0.1 M ammonium nitrate and 0.001 to 0.1 g / liter of a chelating agent is added in a range of 0.1 to 20 times by mass with respect to the waste oil.
[5] The method according to [3] or [4], wherein the chelating agent is EDTA, NTA, DTPA, GLDA, HEDTA, GEDTA, TTHA, HIDA, or DHEG.
[6] A method for recovering oil from which ash has been removed, comprising adding ammonium sulfate to waste oil, stirring and allowing to stand, and then separating the oil.
[7] The method according to [6], wherein a saturated aqueous ammonium sulfate solution is added to waste oil.
[8] The method according to any one of [1] to [7], wherein the waste oil is an emulsion containing ash. [9] The method according to any one of [1] to [7], wherein the waste oil is a used engine oil or a used industrial lubricating oil.
[10] A waste oil regeneration treatment comprising urea or an aqueous solution thereof.
[11] A waste oil regeneration treatment comprising ammonium nitrate and a chelating agent or an aqueous solution thereof.
[12] The regeneration treatment agent according to [11], wherein the chelating agent is EDTA, NTA, DTPA, GLDA, HEDTA, GEDTA, TTHA, HIDA, EDDS, or DHEG.
[13] A recycling agent for waste oil comprising ammonium sulfate or a saturated aqueous solution thereof.

  According to the present invention, it is possible to provide a regenerative treatment agent that does not cause or is unlikely to produce an emulsion. Further, by using the regenerative treatment agent of the present invention, it is possible to provide a more excellent waste oil regeneration treatment method, and environmental pollution. Reduce emissions of substances, recover unused energy, and promote energy saving.

  The waste oil regeneration treatment agent of the present invention is (1) composed of urea or an aqueous solution thereof, (2) composed of ammonium nitrate and a chelating agent or an aqueous solution thereof, and (3) composed of ammonium sulfate or a saturated aqueous solution thereof. . When used as a treatment agent, the urea aqueous solution has a concentration of 0.001 to 0.1 M. However, as a regeneration treatment agent, the concentration is the same as or higher than that, and diluted at the time of use. And may be used. The higher concentration can be, for example, 1 to 10M, but is not intended to be limited to this range.

Examples of chelating agents include EDTA (ethylenediaminetetraacetic acid tetrasodium salt), NTA (nitrilotriacetic acid trisodium salt), DTPA (diethylenediaminepentaacetic acid pentasodium salt), GLDA (L-glutamic acid diacetic acid tetrasodium salt), HEDTA (hydroxyethylethylenediaminetriacetic acid trisodium salt), GEDTA (glycol etherdiaminetetraacetic acid tetrasodium salt), TTHA (triethylenetetramine hexaacetic acid hexasodium salt), HIDA (hydroxyethyliminodiacetic acid disodium salt), EDDS ( Ethylenediamine disuccinic acid tetrasodium salt) or DHEG (dihydroxyethylglycine sodium salt).
The mixing ratio of ammonium nitrate and chelating agent is suitably in the range of 0.1: 1 to 1: 0.1, for example.

  An aqueous solution containing ammonium nitrate and a chelating agent, when used as a treatment agent, has a concentration of 0.001 to 0.1 M ammonium nitrate and a concentration of 0.001 to 0.1 g / liter of chelating agent. Or a higher concentration that is diluted during use. A higher concentration can be, for example, 1-10 M for ammonium nitrate and 1-100 g / liter for a chelating agent, but is not intended to be limited to this range.

  The thing which consists of ammonium sulfate or its saturated aqueous solution can add the ammonium sulfate more than saturation amount to water, or can remove the ammonium sulfate precipitation from there. Ammonium sulfate exhibits a high ability to regenerate waste oil by using a saturated aqueous solution.

The present invention includes a step of adding the waste oil regeneration treatment agent to the waste oil as an aqueous solution, mixing and stirring (first step), then allowing the resulting mixture to stand, and then separating the oil (second step) It is a method of recovering oil from waste oil containing.
Hereinafter, it demonstrates in order of a process.

  First step: The regeneration treatment agent added to the waste oil may be solid, but in order to obtain a higher quality reclaimed oil, it is preferably added to the waste oil as an aqueous solution. When an aqueous solution is used, in the case of the urea, it is 0.001 to 0.1M, preferably 0.002 to 0.05M, particularly preferably 0.005 to 0.02M. In the case of ammonium nitrate and a chelating agent, the ammonium nitrate is 0.001 to 0.1M, preferably 0.002 to 0.05M, particularly preferably 0.005 to 0.02M. The chelating agent is 0.001 to 0.1M, preferably 0.002 to 0.05M, particularly preferably 0.005 to 0.02M. The molar ratio of ammonium nitrate to chelating agent is, for example, in the range of 0.001: 1 to 1: 0.001, preferably in the range of 0.01: 1 to 1: 0.01, more preferably in the range of 0.1: 1 to 1: 0.1. As the ammonium sulfate, a saturated aqueous solution is used as described above.

  The amount of the treating agent aqueous solution with respect to the amount of waste oil is usually 0.1 to 20 times by mass, preferably 0.5 to 8 times by mass, and more preferably 0.8 to 5 times by mass. In addition, the amount of the treatment agent added to the waste oil may be excessively added so that the removal component contained in the waste oil can be sufficiently captured, and the excess added is recovered after the treatment as described later, Can be reused. These conditions can be appropriately determined depending on the scale of the processing apparatus and the processing time. In addition, when using a saturated aqueous solution of ammonium sulfate, the amount of the treating agent aqueous solution relative to the amount of waste oil is preferably relatively small, for example, 0.01 to 2 times by mass, and more preferably 0.05 to 1 times by mass.

  After the aqueous treatment agent solution is added to the waste oil, the treatment agent and the waste oil are sufficiently brought into contact and reacted by mixing and stirring. The atmosphere at the time of mixing / stirring (during reaction) can be carried out at 0 to 100 ° C., preferably 10 to 90 ° C. Usually, it is preferable to carry out at room temperature, for example, 15-30 degreeC from the point of workability | operativity, For example, reaction time can be shortened by carrying out at 50-90 degreeC, Preferably it is 60-80 degreeC. Moreover, although reaction time changes with reaction temperature etc., it is normally 5 minutes-20 hours. In order to ensure a sufficient contact time for the reaction, it is preferably 20 minutes to 15 hours, and more preferably 40 minutes to 8 hours. Stirring conditions are 100-3000 rpm by the generally used stirrer, Preferably, it is 200-2000 rpm. Due to the reaction between the treatment agent and the waste oil, the components contained in the waste oil as residual carbon and ash, for example, in engine waste oil, the components (calcium, zinc, phosphorus, etc.) that are contained in a relatively large amount as salts (solid) Generate (precipitate). In addition, the density | concentration of the processing agent at the time of mixing and stirring can be measured with a simple pH meter.

Second step: After completion of the reaction, the mixture obtained is allowed to stand, and then the oil is separated. After completion of the reaction, the solid (sludge), the oil component, and the aqueous phase can be separated from each other by standing due to the difference in specific gravity. The standing time is usually 6 hours to 3 days, and it is preferable to stand for 6 to 24 hours.
In order to further increase the separation efficiency, it is preferable to perform the separation operation by centrifugation. In particular, when a saturated aqueous solution of ammonium sulfate is used, a hardly soluble precipitate is produced. Therefore, in order to separate this from the oil, it is preferable to perform the separation operation by centrifugation. As the separation means, a conventional centrifuge can be used, but it is desirable that the solid, oil, and water can be separated and the solid can be automatically discharged. Centrifugation conditions are not particularly limited and depend on the performance of the centrifuge. Centrifugation is usually performed at room temperature at 1000 to 20000 rpm, preferably 1200 to 15000 rpm for 5 minutes to 1 hour, preferably 10 to 50 minutes. Do. By this separation operation, residual carbon can be separated and removed.

  By this separation operation, solids (sludge: concentrates such as Na, Si, Ca, Zn) and moisture (aqueous solution) can be recovered and used. For example, since the regeneration treatment agent remains in the moisture, it is preferable to collect the filtrate after filter filtration and reuse it as the treatment agent for cost reduction. The sludge can also be recycled as a solid fuel by removing moisture as much as possible with a filter press and mixing it with combustible materials (for example, sawdust that does not generate harmful gas even when burned). The water removed here is preferably recovered and reused as a treating agent.

  In order to further increase the purity, the separated oil is further treated by adding an acid aqueous solution or an aldehyde aqueous solution (third step), and after the treatment, further adding water and washing with water (fourth step). Step), and finally, a step (fifth step) of separating oil from the mixture.

Third step: An acid or aldehyde is added to the separated oil and mixed and stirred. In this case, it is preferable to add as an aqueous acid solution or an aqueous aldehyde solution, and by adding these aqueous solutions, Na salt and SiO ₂ salt are formed by easily reacting with salts remaining in the oil and unreacted remaining alkali. And can be easily transferred to the moisture side.

  The acid is not particularly limited as long as it has the above-described addition effect, and examples thereof include sulfuric acid, carboxylic acids having 1 to 10 carbon atoms, and aliphatic oxycarboxylic acids having 1 to 10 carbon atoms. it can. The carboxylic acid having 1 to 10 carbon atoms is, for example, an aliphatic carboxylic acid having 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms. Specifically, formic acid and acetic acid are preferable. The aliphatic oxycarboxylic acid having 1 to 10 carbon atoms is, for example, one having 1 to 5 carbon atoms, more preferably an aliphatic oxycarboxylic acid having 1 to 3 carbon atoms. Specifically, glycolic acid is preferable.

  As an aldehyde, it is preferable that it is a C1-C10 aliphatic aldehyde, More preferably, it is C1-C5, More preferably, it is C1-C3 aliphatic aldehyde, Specifically, glyoxal is preferable. These acids or aldehydes can be used alone or in combination. In the present invention, it is preferable to use sulfuric acid or glyoxal. These carboxylic acids, aliphatic oxycarboxylic acids, and aliphatic aldehydes have high oil solubility when the number of carbon atoms is large, and it is difficult to separate unreacted residues in a later step. The concentration of the acid or aldehyde aqueous solution is not particularly limited, but in the case of a strong acid such as sulfuric acid, it is usually 0.05 to 2N, preferably 0.1 to 0.5N. The compounds showing weak acidity such as carboxylic acid, aliphatic oxycarboxylic acid and aldehyde are usually 100% or 1 to 99% by weight aqueous solution, preferably 5 to 80% by weight aqueous solution. The amount of the acid or aldehyde aqueous solution added to the oil separated in the second step is not particularly limited, but is 0.1 to 5 times by mass, preferably the same amount to 2 times by mass with respect to the oil. . The treatment time in the third step is not particularly limited, but is usually preferably 5 minutes to 5 hours, and more preferably 10 minutes to 3 hours. During this time, it is preferable to mix and stir under the same conditions as in the first step.

  Fourth step: After treatment with an aqueous acid solution or an aqueous aldehyde solution, further washing with water is performed. The amount of water used is not particularly limited, but is usually the same amount to 5 times by mass with respect to the acid aqueous solution or the mixed solution after the aldehyde treatment. Preferably, it is the same amount to 2 times by mass. Washing with water promotes the migration of water-soluble components from the oil to the moisture side, and facilitates their removal in the fifth step. As a result, a reclaimed oil with a higher degree of purification can be obtained. In the washing step, it is preferable to mix and stir under the same conditions as in the first step.

Fifth step: After the water washing treatment, the oil is separated from a mixed solution containing an acid or aldehyde, an aqueous solution containing Na salt or SiO ₂ salt, an oil, and sludge. The separation process can be performed by the same method as in the second step. Separation conditions can also be set appropriately within the above range.

  Through the above steps, a reclaimed oil from which impurities such as metal components have been removed from the waste oil can be obtained. In particular, the ash content (metal content) can be reduced by utilizing the regeneration treatment method of the present invention. The metal content in the obtained reclaimed oil is confirmed by elemental analysis by ICP (inductively coupled plasma emission analysis) method, particularly 500 ppm by mass or less, preferably 100 ppm by mass or less, in the case of calcium and zinc contained in a large amount in waste oil. More preferably, it is reduced to 50 ppm by mass or less, particularly preferably 10 ppm by mass or less, and a regenerated oil in which the metal content is reduced by 60 to 99% by mass or more can be obtained. The ash content is preferably 0.6% by mass or less, more preferably 0.3% by mass or less, still more preferably 0.1% by mass or less, and particularly preferably 0% as sulfated ash as defined in JIS K2272. 0.05% by mass or less. By setting the sulfated ash content to 0.05% by mass or less, it is possible to obtain recycled heavy oil that conforms to one of the JIS standards for heavy oil. Further, the residual carbon content (as defined in JIS K 2270) in the reclaimed oil is preferably 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.3% by mass or less. is there. Recycled oil is used as recycled heavy oil as well as recycled heavy oil. These reclaimed oils can be further refined by conventional refining methods for fuels and lubricating oils such as atmospheric distillation, vacuum distillation, catalytic cracking, catalytic reforming, hydrotreating, solvent extraction, etc., or a combination of these processing methods as appropriate. In addition, known additives such as fuel additives and lubricating oil additives can be optionally blended as necessary.

  The waste oil regeneration treatment method using the waste oil regeneration treatment agent of the present invention is effective for waste oil containing impurities such as ash and residual carbon, and is effective if it is generally handled as waste oil. It is particularly suitable for used oil such as used engine oil containing a relatively large amount of ash or used industrial lubricating oil (not containing chlorine-based cutting oil). Used engine oil includes engine oil collected from service stations (S / S), maintenance shops, etc., or engine oil that cannot be sold in long-term inventory, non-standard engine oil, and mixed oils such as those. It is. Industrial lubricants include non-chlorine cutting oils, hydraulic fluids, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
A screw tube (50 ml) with a lid placed in an experimental apparatus was placed on a magnetic stirrer with a stirring bar (diameter 4 mm × length 10 mm) and operated at room temperature. The amount of ash was taken in a 30 mL platinum crucible, and concentrated nitric acid was added and placed in a sand bath set in a draft and heated. The aqueous nitric acid solution was evaporated to dryness. The platinum crucible was placed in an electric furnace and fired at 1200 ° C. Quantification of heavy metals in ash was measured with an atomic absorption photometer (HITACHI A-2000).

experimental method
Measurement of ash in untreated WO and analysis of heavy metals contained in ash
Sample waste oil 5ml (3.3967g) was weighed in a 30ml platinum crucible, 3ml of concentrated nitric acid was added thereto, and placed in a sand bath set in a draft and heated. After about 3 hours, the aqueous nitric acid solution was evaporated to dryness. This operation was then repeated twice. After heating, the sample oil was completely oxidized and disappeared. A black residue remained in the platinum crucible. Further, the platinum crucible was placed in an electric furnace and heated at 1200 ° C. for 1 hour. A small amount of concentrated nitric acid was added to the obtained ash, and distilled water was added to the ash, which was then washed into a 20 ml volumetric flask and made into a 20 ml solution with distilled water.
For the analysis, atomic absorption spectrophotometry was used, calibration curves were prepared for standard solutions manufactured by Wako Pure Chemical Industries, Ltd., Pb, Zn, and Ca, and the respective contents were obtained by collating them.

Regarding removal of ash by washing WO with various solutions, 10 ml of various solutions were added to 5 ml of sample waste oil and stirred at room temperature for 4 hours. Thereafter, heavy metals in the sample waste oil layer and the water layer were analyzed. The aqueous solution shown in Table 1 was used as the solution. The results are shown in Table 1.
After stirring, the state of the emulsion layer formed at the interface between the oil phase and the aqueous phase after standing for 1 hour was visually determined and evaluated as follows.
Δ: Emulsion layer thickness is 3 mm or more ○: Emulsion layer thickness is 1 mm or more and less than 3 mm ◎: Emulsion layer thickness is less than 1 mm

  From the results shown in Table 1, when using the treatment agent of the present invention, the removal of lead, zinc and calcium, which are impurities, is equivalent to or more than when water glass (sodium silicate) described in Patent Document 1 is used. In addition, the state of the emulsion layer formed at the interface between the oil phase and the aqueous phase after standing was superior to the case of using the water glass (sodium silicate) described in Patent Document 1.

Example 2
Using the same apparatus and analysis method as in Example 1, waste oil treatment experiments using ammonium sulfate as the treating agent of the present invention were conducted. 0.5 ml of a saturated aqueous solution of ammonium sulfate prepared by adding 100 g of ammonium sulfate to 100 ml of water, or an aqueous solution obtained by adding 0.01 g of EDTA to 2 ml of this saturated aqueous solution of ammonium sulfate was added to 5 ml of waste oil, and then at room temperature as in Example 1. Then, the sample waste oil layer and the aqueous layer were centrifuged at about 1200 rpm for 30 minutes, and heavy metals in each layer were analyzed. The results are shown in Fig. 1 together with the waste oil data before treatment. In addition, the total mass of ash was 0.52% of the waste oil before treatment, whereas it was 0.20% in a 0.5 ml saturated aqueous solution of ammonium sulfate, and in a EDTA system of 0.5 ml + 0.01 g of saturated aqueous ammonium sulfate solution, It was 0.21%.

  From the results shown in FIG. 1, heavy metal was significantly removed by adding 0.5 ml of a saturated aqueous ammonium sulfate solution to 5 ml of waste oil, and no generation of emulsion was observed.

  The present invention is useful in the field of waste oil treatment.

Results of Example 2.

Claims (13)

A method of recovering oil from which ash has been removed, including adding urea to waste oil, stirring and allowing to stand, and then separating the oil. The method according to claim 1, wherein 0.001 to 0.1 M urea aqueous solution is added in a range of 0.1 to 20 times by mass with respect to the waste oil. A method of recovering oil from which ash has been removed, comprising adding ammonium nitrate and a chelating agent to waste oil, stirring and allowing to stand, and then separating the oil. 4. The method according to claim 3, wherein an aqueous solution containing 0.001 to 0.1 M ammonium nitrate and 0.001 to 0.1 g / liter of a chelating agent is added in a range of 0.1 to 20 times by mass with respect to the waste oil. The method according to claim 3 or 4, wherein the chelating agent is EDTA, NTA, DTPA, GLDA, HEDTA, GEDTA, TTHA, HIDA, or DHEG. A method of recovering oil from which ash has been removed, comprising adding ammonium sulfate to waste oil, stirring and allowing to stand, and then separating the oil. 7. The method of claim 6, wherein a saturated aqueous ammonium sulfate solution is added to the waste oil. The method according to any one of claims 1 to 7, wherein the waste oil is an emulsion containing ash. The method according to any one of claims 1 to 7, wherein the waste oil is used engine oil or used industrial lubricating oil. Recycling agent for waste oil consisting of urea or its aqueous solution. A waste oil reprocessing agent comprising ammonium nitrate and a chelating agent or an aqueous solution thereof. 12. The regeneration treatment agent according to claim 11, wherein the chelating agent is EDTA, NTA, DTPA, GLDA, HEDTA, GEDTA, TTHA, HIDA, EDDS or DHEG. A reprocessing agent for waste oil comprising ammonium sulfate or a saturated aqueous solution thereof.