WO1998010045A1

WO1998010045A1 - Method of refining waste oils (petroleum products)

Info

Publication number: WO1998010045A1
Application number: PCT/IB1996/000906
Authority: WO
Inventors: Zinaida T. Dimitrieva
Original assignee: Destiny Oil Anstalt
Priority date: 1996-09-09
Filing date: 1996-09-09
Publication date: 1998-03-12
Also published as: AU6752096A

Abstract

Ecology of the environment and conservation of energy-containing mineral hydrocarbon raw material due to secondary use after treatment of the refined oils and cutting oils in the metal-working industry and in machine engineering. The method involves intensive treatment, without heating, of the raw material by extractant-absorbents in the form of aqueous solutions of phosphoric, hydrochloric and sulphuric acids, caustic soda at concentrations from 2 up to 88 % by mass with a volumetric ratio for the 'extractant:raw material' from 1:1 up to 1:60, without drying or subsequent drying and neutralisation over oxides, hydroxides, salts of alkaline and alkali-earth metals. The method includes treatment of the raw material with the adsorbent where the raw material is filtered through charcoal or hard coal or coke cut with sand in a mass ratio from 1:0.5 to 1:45 and particle dispersion of 160-400 νm.

Description

METHOD OF REFINING WASTE OILS (PETROLEUM PRODUCTS)

Field of Technology

The invention relates to the area of conservation of energy-containing mineral hydrocarbon raw material and protection of the environment. The invention may be used successfully in the process of extraction-sorption refining of waste oils and cutting solutions, used in metal working production. The invention can also be used in refining machine (lubricating) oils.

Background Art

Because of the absence of production process methods to refine waste oils the metal working industry burns them or pours them into disposal sites. Therefore, the necessity for refining waste oils is determined by the large losses of energy-containing mineral hydrocarbon raw materials and the problem of soil, water and air pollution associated with this.

Waste industrial oils and cutting fluids as a rule are contaminated with resinous and oxidised products, water, metals, carbon black, peroxides and abrasive powders. All known methods for recovering hydrocarbon raw material, waste oils and cutting fluids are based on technologies of mechanical, absorption and extraction treatment.

A number of methods are known for partial (non-intensive) treatment of oils and petroleum products. For example, by heating the waste oil only gaseous products and light hydrocarbons are removed (US patents: 4894140; C10G51/02, C10M1/75), and by heating the oil in the presence of a coagulant mechanical impurities are deposited (US patents: 4948493, C10G29/00, 5234577, C10G1/04).

Using a filter made up from composition material and activated carbon polycyclic aromatic compounds exclusively are removed from the used lubricating oil (US patent: 5225081, B01GD37/00). In order to remove water from waste oils, quaternary pyridine salts, ammonia or betaine and polyamines are used (DE patents: 3116470, ClOMl l/00, 4317047, C10M175/04, 4317046, C10M175/04) as well as zinc chloride, isopropyl spirit in conjunction with active earth (DE patents: 2421903, ClOMl l/00, FR patent 2427384, ClOMl l/00) and quaternary ammonium base (GB patent: 2075047, C10M11/00). Rendering waste oils harmless is conducted in more strict conditions, - the oil is treated with dispersed metallic sodium at high temperature with its subsequent distillation (US patent: 4255252, ClOMl l/00).

Removing hydrogen peroxides and peroxides from waste oils is carried out using sodium hydroxide (Application WO 93/18122, CIOM 175/006) metal thiophosphate (US patent 5209839, CIOM 175/02), KOH and NaOH mixtures with high temperature conditions for treating the oil (US patent 4252637, ClOMl l/00), and acidic earth material (application JP: 3-47314, C10G25/00).

Demetallisation of the used oils and cooling fluids in carried out by means of the transfer (transformation) of free metals into water soluble compounds (salts). For this the oil and cooling fluids are treated with aqueous solutions while heated to 50-150°C (DE patent: 3916732, C10G53/10, C10M175/04, 3920869, C10M175/02; EP application 341802, CIOM 175/00), also the oils and cutting fluids are dispersed in ethylenediaminetetra-acetic acid at high temperature (application WO 94/01519, C10M175/02) . Metal compounds are removed from oils and cutting fluids by contact with free phosphorus (US patent: 4419225, C10G17/00) or with an absorbent containing active metal of high-melting oxide (US patent: 5173173, C10G61/06, 5204838. C10M175/00), or by heat extraction with aqueous solutions of ammonium and aluminium salts (US patents: 4151072, ClMl l/00; 4204946, ClOMl l/00; 4265733, ClOMl l/00; 411774, ClOMl l/00; WO application 92/01033, C10M175/00; DE application 3916732, C10G53/10) and alkali (WO application 94/21761, C1M175/00; GB application 2134918, ClOMl l/00).

Particles of carbon black are removed from waste lubricating oils by contact with heterogeneous strong bases. For strong bases, use is made of oxides, hydroxides, sodium carbonate, barium, calcium, magnesium, aluminium, zinc and mixtures of these substances (EP application 416907, C10M177/00).

Light hydrocarbons are removed from waste sponge oils by gas extraction, for example with liquid propane, using regimens of supercritical technology (FR application 2440396, C10G21/14, GB application 2101154, ClOMl l/00).

Selective treatment of oil fractions and hydrocarbon mixtures (including waste oils) to remove aromatic and unsaturated hydrocarbons is carried out using the following as solvents: phenol (DD patents: 216478, C10G21/16; 226155, C10G21/16), tetrahydrofuran (US patent 4302825, C10G21/16; FR application 2492840, ClOMl l/00), amino alcohols (PL patent 165606, CIOM 175/02) and glycol mono-ethers (JP application 61-46517B. C10G29/22).

Methods for general treatment of waste oils, as a rule, include a multi-stage treatment of the raw material with concentrated mineral acids at high temperature. Thus, in the methods of JP application: 1275692, C10G19/02; 1271487, C10G31/09), waste motor oil and the hydrocarbon fraction are treated whilst heating with a mixture of H₃ PO₄ and a surfactant substance, then with an alkali, water and coagulant. After these stages, the raw material is passed through a triple phase separator and vertical dish-shaped centrifuge and, for treating the hydrocarbons, acid is used on a carrier (JP application 4-80076, 10G 17/095).

A condition of implementing the known methods for recovering waste motor oils is the use of a high temperature regime of acid-alkali extraction using complex and long-lasting surfactant substances and coagulants.

In this method, with the aim of utilising used oils, they are treated, with the application of heat, by an aqueous solution of a mixture of two strong acids and/or a solution of two salts of weak bases and powerful acids. The treated raw material is dehydrated, dried and separated from the precipitated deposit (WO application 91/00329, C1M175/00; DE application 3920869, C10M175/02). A similar method, except that it includes treatment of the oil raw material, with the application of heat, using an aqueous solution one powerful acid and/or a solution of a single salt of a weak base (DE application 3900159, C10G17/04). To provide the conditions for these methods, the application of highly concentrated acids is required in conjunction with very toxic reagents: hydrazine, piperazine, guanidine, carbazide, morpholine. Use of the chemical compounds indicated carries a great risk of their polluting the environment, with added complications and increased cost of the technical process at all stages. Moreover, a condition of known methods requires heating up the raw material being treated to 200-300° which makes the process wasteful of energy.

The method of recovering waste oil (patent DD 267258, C10G 17/06) heavy petroleum distillates (application FR 2393051 , C10G17/06) and the method of separating recovery products of waste lubricating oils (patent DD 300676, CIOM 175/00) are based on stages, treating the raw material with concentrated H₂SO₄, and neutralising and filtering the oil. It also includes heating to 100°. A variant of the methods of sulphuric acid treatment of used oils and petroleum products at high temperature is the prior treatment of the raw material with sulphiding organic polymers (application DE 2721396, ClOMl l/00).

The basis of the method (patent DD 294725, C10G 17/06) consists in treating the waste industrial oils with concentrated (96%) sulphuric acid at 20-30°C and intensive mixing, with subsequent treatment with water. As a result of the treatment, a mixture of acidic oil and a mixture of acidic resin are produced. Before treatment, the oil is cleaned of mechanical impurities and is dehydrated. One of the significant drawbacks of the established method of treating oil is the fact that, after treating the oil with concentrated H₂SO₄, a stable emulsion is formed in the form of a dark coloured solid mass in which the separation of phases is practically absent over prolonged (8-10 days) settling of this mass. Concentrated H₂SO₄. in contact with oil, causes many secondary processes: sulphonation, oxidation, decomposition, gumming, corrosion of the process equipment. Application of H₂SO₄ (a strong oxidant) for treating oil complicates the meeting of sanitary-engineering requirements, and puts a burden on the process equipment by introducing prior stages for the separation of mechanical impurities and for dehydration of the raw material before treating it with sulphuric acid. It should be pointed out that the known methods of recovering waste oils effectively contains no recovery stages allowing for restoration of the initial composition and for the quality of the waste oils and they are limited only to the stage of treating the raw material (oil base).

General disadvantages of the known methods for treating waste oils are based on the choice of using either very aggressive reagents, or complex multi-component mixtures, which gives rise to the multi-stage nature of the process and the necessity to employ high temperature regimes.

Disclosure of Invention

A method for refining waste oils (petroleum products), according to the invention, includes intensive contact of the raw material with a liquid extractant-absorbent or with a solid absorbent, without applying heat treatment of the refined mixture.

In order to increase the selectivity, effectiveness and anti-corrosive properties of the method for refining waste oils (petroleum products), phosphoric acid is used as a liquid extractant-absorbent at a concentration in aqueous solution from 5 to 88% by mass and as a volumetric ratio for "extractant-acid":raw material from 1:1 to 1:60 (Table 1). The optimal ratio for "extractan : oil" is in the range of 1 :15 up to 1:30. It is preferable in the refining of oils to use a ratio of "extractant: oil" = 1:20. The volumetric ratio of "extractant: oil" = 1:60 is a summary total and is obtained on the basis of the initial volumetric ratios "extractant : oil" equal to 1:30 or 1:20 and by making use of an increase in the frequency of use of the extractant by 2 or 3 times respectively (Table 2). According to the invention 1 (one) part by volume of the 70-88% phosphoric acid used as extractant treats 25-60 parts by volume of the waste industrial oil with multi-repeated use of the extractant. The frequency rate for use of the extractant in the technical process for refining raw materials depends on the initial "extractant : oil" ratio. The repetition rate changes from 2 to 5 for "extractant : oil" ratios lying between 1:30 to 1:5 respectively with a degree of oil treatment at 98-99%. After a single use of the extractant in refining oil (petroleum product), in every subsequent cycle for treating the raw material, the extractant is applied in the form of an extract from the previous technical process cycle. Multiple use of the extractant significantly reduces the cost (by 2-5 times the cost of the reagent) and simplifies the technical process for refining waste oil (petroleum product).

A significant additional contribution in reducing the costs of the process equipment lies in the fact that after each usage of the extractant the acidity of the oil drops sharply (falling below the norm) which avoids the necessity to employ the process stage of neutralising the oil. Water is absent in the refined oil when using as an extractant 70-80% phosphoric acid. On the basis of results of infra-red and ultra violet spectroscopy, refining the raw material using 5-88% phosphoric acid does not alter the hydrocarbon composition of the secondary oil when compared to the non-used oil.

The duration of contact between the raw material and the extractant depends on the intensity of their mixing, the volume ratio, the scale factor and can vary from 5 minutes up to 2 hours (Table 1, example 27). The duration of phase separation largely depends on the concentration and the chemical nature of the extractant and in this regard it varies from several minutes to several tens of hours (Tables 1 and 3).

The use of secondary oil in metal working increases the rate of throughput when applying fine finishing to ball bearings.

In order to prevent chemical interaction (oxidation, polymerisation, gumming, sulphonation) between the extractant and the useful components of the waste oil (petroleum product) and to reduce the duration of phase separation according to the invention, dilute HCl, H₂SO₄ and Na₂CO, are used as an extractant with subsequent drying and neutralisation of the raffinate.

For refining the raw material, prior treatment is carried out with hydrochloric acid at a concentration of 6-12% by mass, sulphuric acid diluted to 8-40% by mass. The soda content in the solution should not exceed 8-10% by mass in order to avoid the formation of a very resistant emulsion which hinders separation of the raffinate from the extract. The optimal volumetric ratio for the "extractant : raw material" for H₂SO₄ is 1:15. From the point of view of the separation phase duration it is more preferable to use dilute HCl or H₂SO₄ as an extractant rather than Na₂CO₃.

From the point of view of selectivity, effectiveness, technical and economic and ecological parameters of the method, it is preferable to use phosphoric acid as an extractant for the process of refining oils (petroleum products) rather than the acids HCl and H₂SO₄.

In order to eliminate the drying and neutralisation stages from the process of refining waste oils (petroleum products) and to broaden (diffuse) the method, according to the invention, for treating machine (including automobile) oils, use can be made of charcoal or hard coal or coke, mixed with sand using a mass ratio from 1:0.5 up to 1:45, with particle size of 160-400 μm. The sand by itself is a neutral material. In practice it does not clear the raw material of impurities (Table 4, example 87). The application of coal and coke alone as adsorbents is of little use in refining the raw material. Thus, lg of coal by filtering treats only 0.7g of waste industrial oil and lg of coke treats 2.3g of the same oil. According to the invention, the first effect discovered for the method is based on the fact that with massive dilution of the adsorbents with neutral sand by 24-26 times, their adsoφtion capacity for refining oils increases by 20-60 times due to the increase in active surface of the adsorbent. For example, lg of coal, cut with sand in the ratio 1:25 can treat 41.5g of waste industrial oil and 31.5g of motor oil; lg of coke diluted with sand in the ratio 1:26 can treat 41g of used motor oil. This newly-discovered solution for the method, according to the invention, increases the capacity of the adsorbent by 20-60 times and maintains the capacity of the adsorbent just as much and, proportionately with this, reduces the cost of the refining operation for waste oils (petroleum products). The raffinate obtained after filtration of the raw material through coal or coke cut with sand requires no other additional treatment and can be used as intended. Application of the method by cutting with sand using a particle size of less than 160 μm reduces the rate of filtration of the raw material and using a particle size greater than 400 μm reduces the adsorbent capacity and level of treatment for the oil (petroleum product).

Modes for Carrying Out the Invention

Example 1. Into a capacitive extractor capable of mechanical mixing, 100 ml of waste industrial oil are poured and 100 ml of 88% H₃PO₄ (extractant-absorbent). The volumetric ratio "extractant (E): oil (O)" = 1:1. The extraction process is conducted at an agitation rate for the two liquid phases of 900-1200 revolutions per minute (rev/min) at ambient temperature (10-20°C) for a period of 20 minutes. After this, the mixing apparatus is switched off and the extractor, with its contents, is left to settle. After 40-45 minutes a clear separation of the treated mixture occurs, into two layers. The upper layer contains the refined (clarified) oil with a light yellow colour and the lower layer, a dark coloured extract, contains resinous substances, water, mechanical impurities and abrasive powder. The level of treatment (clarification) of the oil under photoelectric colorimetry (PEC) is 99%. Water is absent from the oil.

The experiment is repeated, the only difference being that the mechanical mixing is replaced by ultrasonic mixing with an oscillation frequency of 600-700 Khz. After ultrasonic mixing, the duration of phase separation is reduced to 15-18 minutes and the level of clarification of the oil is 99.7%. Water is absent from the oil.

Example 3. Into a capacitive extractor capable of mechanical mixing, 200 ml of waste industrial oil are poured, to which are added 10 ml of 88% phosphoric acid (H₃PO₄ ,extractant). The volumetric ratio "E:O" in the extractor is 1:20. The extraction process is carried out with a mixing rate for the two liquid phases of 1,100 rev/min at a surrounding extraction temperature of 15° for 2-3 minutes. After this the mixing apparatus is switched off, the extractor with the contents is left to settle. After 45 minutes the mixture separates into two layers. The upper layer contains the refined oil with a light yellow colour and the lower layer, a dark coloured extract, contains resinous substances, water, mechanical impurities and abrasive powder. The level of treatment (clarification) of the oil, by PEC, is 93.5%. After extraction treatment, 170ml of the oil produced is transferred to a storage vessel, to this is added 2.55g (1.5%) of anhydrous NaOH. The oil is left to settle for 5-6 hours over a dryer-neutraliser. The level of clarification of the oil after neutralisation is 99.9%.

Example 6. Into an extractor capable of mechanical mixing, 200 ml of waste industrial oil are poured to which are added 10 ml of 88% H₃PO₄ as extractant. The volumetric ratio "E:O" in the extractor is 1:20. The extraction process is conducted with a mixing rate for the two liquid phases of 1,100 rev/min at a surrounding extraction temperature of 15° for a period of 20 minutes. After this the mixing apparatus is switched off, the extractor with the contained mixture is left to settle. After 28-30 minutes the mixture separates into two layers. The upper layer contains the refined oil with a light yellow colour and the lower layer, a dark coloured extract, containins resinous substances, water, mechanical impurities and abrasive powder. The level of treatment (clarification) of the oil, by PEC, is 99.2%. Water is absent from the oil.

Example 10. Into an extractor capable of mechanical mixing ,150 ml of waste industrial oil are poured to which are added 5 ml of 88% H₃PO₄ as extractant. The volumetric ratio "E:O" in the extractor is 1:30. The extraction process is conducted with a mixing rate for the two liquid phases of 1,200 rev/min at a surrounding extraction temperature of 18° for a period of 15 minutes. After this, the mixing apparatus is switched off and the extractor containing the mixture is left to settle. After 30-35 minutes the mixture separates into two layers. The upper layer contains the refined oil with a light yellow colour and the lower layer, a dark coloured extract, contains resinous substances, water, mechanical impurities and abrasive powder. The level of treatment (clarification) of the oil, by PEC, is 93.5%. After extraction treatment, 127 ml of the oil produced is transferred to a storage vessel, to this is added 1.9g (1.5%) of anhydrous Na₃PO₄ or Na₂SO₄. The oil is left to settle over a dryer-clarifier for 8-10 hours. The level of clarification of the oil after drying, by PEC is 99.5%. Water is absent from the oil. Example 15. Into an extractor capable of mechanical mixing, 100 ml of waste industrial oil are poured to which are added 5 ml of 60% H₃PO₄ as extractant. The volumetric ratio "E:O" in the extraction mixture is 1:20. The extraction process is conducted with a mixing rate for the two liquid phases of 1,200 rev/min at a surrounding temperature of 10° for 20 minutes. After this, the mixing apparatus is switched off and the extractor containing the mixture is left to settle. After 250-260 minutes the mixture separates into two layers. The upper layer contains the refined oil with a light yellow colour and the lower layer is a dark coloured extract. The level of treatment (clarification) of the oil, by PEC, is 97.2%.

All the remaining results were obtained by a similar method and are shown in Table 1 and Examples 2, 4, 5, 7-9, 11-14, 16-26.

Table 1. Operational Parameters for Extraction- Absorption Refining of Waste Industrial Oil Using Phosphoric Acid

Extractant Volumetric Duration of Duration of Degree of Degree of

No.of Concentration Ratio Mixing (contact) Phase Treatment Dryer-Neutraliser by Clarification of

Examp (H₃P0₄) "Extractan Oil" of the Phases, Separation, (clarification) % Mass Oil after drying - le Mass % Minutes Minutes by PEC, % Neutralisation^

1 2 3 4 5 6 7 8

1 1 :1 20 43-45 99.0

2 88 1 :7 30 43-44 97.6 CaO: 1.0 99.2

3 1 :20 2.0 44-45 96.8 KOH; 1.5 99.9

4 10 40-42 98.5

5 15 30-35 99.0

6 20 28-30 99.8

7 25 20-30 99.0

8 30 20-30 97.6

9 1 :30 20 25-35 96.7 Na₂S0₄; 1.0 99.8

10 5 30-35 93.5 Na₃P0₄; 1.5 99.5

11 70 1 :20 20 43-50 96.7

Table 1 ( contd.)

1 2 3 4 5 6 7 8

12 1:1 20 60-62 96.9

1 60 1:4 20 50-55 96.5

14 1:10 20 180-200 96.3 MgS0₄; 1.5 99.8

15 1:20 20 250-260 97.2

16 1:20 10 280-290 96.0

17 1:1 20 40-45 95.7 Zeolites: 4.0 99.0

18 40 1:5 20 60-70 95.8 Na₂C0₃; 2.0 99.4

19 1:10 20 230-240 95.9

NJ

20 1:25 20 300-320 95.3 MgS0₄; 2.5 99.0

21 1:1 20 120-130 96.0

22 20 1:1 4 160-170 96.0

23 1:10 20 360-370 95.5

24 1:1 20 320-340 94.2 Na₂S0₄; 3.0 98.7

25 5 1:10 20 600-620 93.0 Coke; 4.0 97.9

26 1:20 20 900-950 92.5 CaCl₂; 2.0 98.4

Example 27. Into a 200 litre capacity reactor with an anchored agitator are loaded 120 litres of waste (very viscous) black coloured industrial oil and 6 litres with 86% H₃PO₄ as extractant-absorbent. The volumetric ratio "E:O" in the extraction mixture is 1:20. The extraction mixture is stirred at a rate of 900 rev/min for 2 hours at a temperature of 17°. After this, the agitator is switched off and the mixture in the reactor is left to settle. After standing for 5-7 hours the mixture separates into two layers. The treated oil settles in the upper layer with a light yellow colour and a dark coloured extract collects in the lower layer. The refined (up to 98.9%) oil is poured from the reactor into a rack for secondary use in the working of ball bearings. When using the secondary oil, the rate of throughput of metal increases twofold, that is, the productivity of a metal working machine tool increases twofold with the use of secondary oil.

To the remaining extract in the reactor, another 120 litres of waste oil are added, the mixture is stirred at a rate of 900 rev/min for 2 hours at 17°. After leaving the mixture standing for 5-7 hours, the refined oil (up to 98.5%) is separated from the upper layer and is used as secondary oil and to the remaining extract in the reactor yet another 120 litres of waste oil are added, the mixture is stirred at a rate of 1,200 rev/min for 3 hours at 17°. After leaving the mixture standing for 7-8 hours the refined oil (up to 98%) is separated from the upper layer and is used as secondary oil in metal-working.

After the fourth use of the extract the oil is refined up to 20-30%.

The overall volume of treated oil is 360 litres with a "E:O" ratio of 1 :60. In Table 2 values are shown for the use of H₃PO₄ in refining waste oil, depending on the initial "E.O" ratio. Table 2. Frequency of Use of 86% H,PO₄ As An Extractant- Absorbent in Refining Waste Oil.

Example 32. Into an extractor capable of mechanical mixing, 50 ml of waste oil are poured to which are added 50 ml of 2% hydrochloric acid (HCl) as extractant. The volumetric ratio "extractant : oil" in the mixture is 1:1. The extraction process is carried out with an intensive mixing rate for the two liquid phases of 1 ,100 rev/min for 5 minutes. After this the mixing apparatus is switched off and the extractor containing the mixture is left to settle. After 240 hours, the mixture separates into two layers. The upper layer contains the refined oil and the lower layer is a thick, dark coloured extract. The level of refining (clarification) of the oil, by PEC, is 89.7%. The refined oil is poured from the extractor into a container and to it is added lg (2.3% of the initial oil) of anhydrous CaCl, or CaO. The oil is left to settle over a dryer-clarifier for 6-8 hours. The degree of clarification of the oil after drying is 95.6%.

Example 42. Into an extractor capable of mechanical mixing, 150 ml of waste oil are poured to which are added 10 ml of 8% hydrochloric acid (HCl) as extractant. The volumetric ratio "E:O" in the extractor is 1:15. The extraction process is carried out with a mixing rate for the two liquid phases of 1,100 rev/min for 20 minutes. After this the mixing apparatus is switched off and the extractor containing the mixture is left to settle. After 18 hours the mixture separates into two layers. The upper layer contains the refined oil and the lower layer is a viscous, dark coloured extract. The degree of refining (clarification) of the oil, by PEC, is 96.7%. Example 59. Into an extractor capable of mechanical mixing, 300 ml of waste oil are poured to which are added 20 ml of 20% sulphuric acid (H₂SO₄) as extractant. The volumetric ratio "E:O" in the extractor is 1:15. The extraction process is carried out with a mixing rate for the two liquid phases of 1,100 rev/min for 20 minutes. After this the mixing apparatus is switched off and the extractor containing the mixture is left to settle. After 5 hours the mixture separates into two layers. The upper layer contains the refined oil and the lower layer is a viscous, dark coloured extract. The degree of refining (clarification) of the oil, by PEC, is 98.5%.

Example 62. according to patent DD 2947257. Into an extractor capable of mechanical mixing, 100 ml of waste oil are poured to which are added 5 ml of 96% H₂SO₄as extractant. The volumetric ratio of "acid : oil" is 1:20. The mass ratio is 1:10. The extraction process is carried out with intensive mixing of the two liquid phases at a surrounding temperature of 35° for 20 minutes. After this the mixing apparatus is switched off and the extractor containing the mixture is left to settle. After 268 hours the mixture separates into two layers. The upper layer contains a dark coloured, opaque oil and the lower layer is a dark coloured extract. The degree of refining of the oil, by PEC, is 83%. The oil is not purified.

By a similar method all the remaining results were obtained. These are shown in Table 3 and Examples 33-41, 43-58, 60, 61, 63.

Example 64. The industrial oil waste mixture is filtered through a column filled with a mixture of coal : sand = 1 :0.5 with particle size of 160:(250-400) μm. The adsorbent mass is 25g. The filtrate is selected with characteristics with a value equal to the characteristics of the initial standard oil mixture. 118g of treated oil are obtained. The adsorbent capacity is 4.7g of oil to lg of adsorbent.

Example 65. The industrial oil waste mixture is filtered through a column filled with a mixture of coal : sand = 1:15 with particle size of 160 : (250-400) μm. The adsorbent mass is 3g. The filtrate is selected with characteristics having a value equal to the characteristics of the initial standard oil mixture. 85g of treated oil are obtained. The adsorbent capacity is 28.3g of oil to lg of adsorbent.

Example 66. The industrial oil waste mixture is filtered through a column filled with a mixture of coal : sand = 1:25 with particle size of 160 : (250-400) μm. The adsorbent mass is 2g. The filtrate is selected with characteristicss having a value equal to the characteristics of the initial standard oil mixture. 83g of treated oil are obtained. The adsorbent capacity is 41.5g of oil to lg of adsorbent.

Table 3. Extraction Conditions for Refining Waste Oil Diluted with Acids and Soda

No. of Extractant Volumetric Ratio Duration of Phase Duration of Phase Degree of Oil Dryer by Degree of

Example Extractant Concentration by "Extractant:Oil" Contact, Minutes Separation, Hours Treatment of Oil Mass, % Clarificati

M;ιss,% by PEC % on of Oil after Drying, Ψo

1 2 3 4 5 6 7 8 9

32 HCl 2 1:1 5 240 89.7 CaCI₂;2.3 95.6

33 4 1:1 5 240 90.1

34 6 1:1 5 96 91.0

35 6 1 :5 10 53 91.3

36 6 1 :5 20 20 91.7 MgS0₄; 2.0 97.0

37 6 1 :15 20 20 92.0

38 8 1:1 5 24 92.1 Na₂CO,: 2.5 98.5

39 8 1:3 20 20 92.4

40 8 1 :5 25 20 92.8

41 8 1:10 20 18 93.9

42 8 1 :15 20 18 96.7

43 8 1 :20 20 18 95.3 Zeolites: 3.0 99.4

44 10 1 :1 5 18 94.9 Coke: 4.0 98.0

45 12 1 :1 5 14 94.5

46 12 1 :1 20 15 94.0 CaO: 1.5 98.7

47 20 1 :1 5 2 82.0 Dark Coloured

48 20 1:1 20 1.5 82.0 Oil (opaque)

49 Na₂CO, 2 1 :1 30 250 89.0 CaCI₂; 2.5 99.5

50 5 1:10 20 48 92.0 NaOH; 2.3 98.7

51 10 1 :20 20 120 93.0 CaCl₂; 1.8 97.2

Example 72. The waste motor oil is filtered through a column filled with a mixture of coal : sand = 1:20 with particle size of 160 : (250-400) μm. The adsorbent mass is 2g. The filtrate is selected with characteristics having a value equal to the characteristics of the initial standard oil. 48g of treated oil are obtained. The adsorbent capacity is 24g of oil to lg of adsorbent.

Example 73. The waste motor oil is filtered through a column filled with a mixture of coal : sand = 1:24 with particle size of 160 : (250-400) μm. The adsorbent mass is 2g. The filtrate is selected with characteristics having a value equal to the characteristics of the initial standard oil. 63g of treated oil are obtained. The adsorbent capacity is 31.5g of oil to lg of adsorbent.

Example 81. The waste cutting oil based on a kerosene fraction is filtered through a column filled with a mixture of coal : sand = 1:20 with particle size of 160 : (250-400) μm. The adsorbent mass is 2.5g. The filtrate is selected with characteristics having a value equal to the characteristics of the initial cutting oil. 36.2g of treated oil are obtained. The adsorbent capacity is 14.5g of oil to lg of adsorbent.

In a similar method all the remaining results were obtained which are shown in Table 4 and Examples 67-71, 74-80, 82-87.

Table 4. Parameters for Adsorption Treatment of Waste Oils and Petroleum Products at 18-23°.

No.of Refined Product Adsorbent Mass Ratio Particle Size, Adsorbent Example Composition μm Capacity g/g

1 2 3 4 5 6

64 Industrial Oil Coal : Sand 1:0.5 160 4.7 250-400

65 1:15 160 28.3 250-400

66 1:25 160 41.5 250-400

67 Coke : Sand 1:30 250-400 13.3 250-400

68 1:30 160 13.0 160-250 9 1:40 160 20.0 160-250 0 1:45 160 14.7 160-250 1 Motor Oil Coal : Sand 1:1 160 8.5 250-400 2 1:20 160 24.0 250-400 3 1:24 160 31.5 250-400 4 1:30 250-400 6.7 250-400 5 Coke : Sand 1:1 160 4.4 160-250 6 1:15 160 12.0 160-250 7 1:26 160 41.0 160-250 8 1:45 160 9.2 160-250 9 1:48 160 7.3 160-250 0 Cutting Oil Based on Coal : Sand 1:1 160 10.2 Kerosene Fraction 250-400 1 1:20 160 14.5 250-400 Table 4 (contd.)

2 3 4 5 6

1 :2 160 6.6 160-250

Coke : Sand 1 :25 160 8.9 160

1:45 160 11.5 160

Mixture of Industrial Coal 160 0.7 Oils

Coke 160 2.3

Sand 160 0.2 250

Claims

1. A method of refining waste oils (petroleum products), including high temperature treatment of the raw material by concentrated sulphuric acid with subsequent treatment with water, alkali, coagulant and filtration, differing in that the method involves, without heating, intensive contacting of the raw material with a liquid extractant-absorbent or with a solid adsorbent.

2. A method as per para.l, differing in that, in the capacity of a liquid extractant- absorbent, use is made of aqueous solutions of phosphoric or sulphuric or hydrochloric acid or caustic soda at concentrations from 2 up to 88% by mass with a volumetric ratio for the "extractant : raw material" from 1:1 up to 1:30, with subsequent drying and neutralisation or without drying and neutralisation of the refined oil (petroleum product).

3. A method as per para.2, differing in that, in refining the treated oil (petroleum product) the liquid extractant-absorbent is used repeatedly as an extractant, up to 5 times, with an increase of the summary "extractant : raw material" ratio up to 1:60.

4. A method as per para.2, differing in that, in the capacity of a dryer-neutraliser for the refined oil (petroleum product), when required, use is made of oxides, hydroxides, salts, of alkaline and alkali-earth metals as well as coke and zeolites.

5. A method as per para.l, differing in that, contact between the extractant-absorbent and the treated raw material is by wave mixing or by atomisation (impact) of fine jets of extractant-absorbent into a stationary layer of the raw material.

6. A method as per para.l, differing in that, in the capacity of a solid adsorbent, use is made of charcoal or hard coal or coke cut with sand in a mass ratio from 1 :0.5 to 1 :45 and particle dispersion of 160-400μm.

7. A method as per para.l, differing in that, contact between the adsorbent and the raw material is based on filtering of the raw material through a stationary adsorbent layer.