JPS5912996A - Repurification of used lubricating oil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to the repurification of used lubricating oils.

More particularly, the present invention relates to the repurification of used lubricating oils by evaporation.

The present invention relates to a method for regenerating and repurifying waste lubricating oil. In particular, the present invention provides a method that is simple and reduces the tendency for caulking, cracking, and fouling inherent in other refining processes.

Large and increasing amounts of used lubricating oil, particularly crank base oil from diesel and other internal combustion engines, are generated each year. These waste oils contain oxidation and decomposition products, water,
Particulate matter, metals and carbon.

Contaminated by petroleum additives. These contaminants make the oils unsuitable for continuous use. Waste oil (waste oil is generally ashed and disposed of in land-based landfills as the costs of recycling and re-refining become excessive, or is used for oil extraction for road dust control. Due to increased prices of fuels and lubricants, combined with certain demand and depletion, a need has arisen for an effective low cost waste oil refining process.

In recent years, some small-scale re-refining processes have been implemented in which oil is recovered for market use. However, these recovery methods represent a small percentage of the total amount of used lubricant due to the high cost involved and the narrow profit margins that they involve.

The ever-increasing shortage and resulting high prices of petroleum, particularly high-grade lubricating oil stocks, currently require the selective removal of undesirable contaminants from conventional motor oils and the removal of undesirable contaminants contained in such oils. This represents a positive incentive to reuse valuable high-quality lubricating ingredients.

A number of waste oil production methods are known from the prior art. For example, US Pat. No. 3,639,229 describes a method in which a mixture of aliphatic monohydric alcohols of 4-5 carbon atoms and light hydrocarbons is added to waste oil. The mixture settles into 6 layers.

The top 1μ oil layer is recovered, treated with sulfuric acid, and then purified using conventional methods. U.S. Patent No. 3.919.076
Issues include removal of water from waste oil, addition of saturated hydrocarbon solvents, precipitation of mixtures to recover oil/solvent mixtures, removal of solvents, vacuum distillation of residual oils to collect selective fractions, and catalysis of that fraction. Hydrogenation above, removing light end fractions) IJ
A method is described that includes soaking and filtration of the residual product. U.S. Pat. No. 4,124,492 discloses a method for regenerating useful hydrocarbon oil from contaminated waste oil by dewatering the waste oil and then dissolving the dehydrated oil in a selected amount of isopropanol. has been done. Undissolved waste materials are separated and the remaining oil/solvent fraction is distilled to recover decontaminated oil and solvent. The recovered oil is further clarified by treatment with bleaching clay or activated carbon at high temperatures. U.S. Pat. No. 4,021,333 describes a process for re-refining spent oil that involves distilling a volatile pre-cut followed by East-type distillation carried out at reduced pressure. The use of a demister means is preferred to minimize the introduction of material into the distillate, and distillation is continued until the desired recovery is obtained. Impurities present in the distillate are extracted.

The present invention provides a method for refining used oil containing lubricating oil. The method according to the invention uses used oil or
Reduces the tendency to coke, crack and foul equipment. In addition, one key carrier effect of the light end fraction is achieved by a particular type of circulation that forms part of the process" (c
The recovery of large amounts of lubricating oil is also possible due to the effect of the lubricating oil.

Thus, in one aspect, the present invention is directed to increasing the yield of recovered lubricating oil without subjecting the waste oil feed to temperatures that create coking, cracking, or contamination conditions. In another aspect, the present invention relates to a method of varying the flow of the soft end circulation to achieve a desired viscosity of a lubricating oil. Still other aspects of the present invention relate to achieving desirable recovery of lubricating oil from waste oil feeds while reducing blackness.

In accordance with a further aspect of the invention, the waste oil feed undergoes an initial distillation in which volatile pre-cuts are removed from the spent oil to provide an oil containing lubricating oil. The distillation can also remove water, gasoline, etc., or these components can be removed before the distillation.

The resulting oil is then evaporated to produce heavy and light fractions prior to evaporation of the resulting oil, reducing the tendency for coking, cracking and fouling during the evaporation period and increasing lubricating oil recovery. A portion of the light fractions is circulated and mixed into the resulting oil in an effective amount to reduce the evaporation temperature.

According to another aspect, the invention further includes evaporating the heavy fraction obtained from evaporation of the resulting oil to form a heavy lubricating fraction and a residual fraction.

Furthermore, the evaporation of the heavy fractions still evaporates the heavy fractions before the evaporation of the heavy final fractions due to the lower evaporation temperature, which reduces the tendency to coking, cranking and fouling during evaporation, and increases lubricant recovery. This includes recycling the lubricating fraction into the heavy fraction. Generally, before evaporation, the amount of distillate obtained and recycled to the heavy fraction is approximately 5 parts by weight of the fraction to be evaporated and 6 parts by weight of the fraction to be evaporated.
00 heavy hanger.

According to another aspect of the invention, a method is provided in which a used oil containing lubricating oil is re-refined by distillation of the used oil to remove volatile pre-distillates to provide an oil containing lubricating oil. be done. Thereafter, the resulting oil is transferred to a stirred thin-film evaporator or a wiped-film evaporator.
(eVaporator) or other suitable heat transfer device to form heavy and light fractions, the lubricating oil being contained in the light fraction. The heavy fraction obtained from the evaporation of the resulting oil is further evaporated to form a heavy lubricating fraction and a residual fraction, and the evaporation is carried out using an agitated thin-film evaporator or a mesh-film evaporator or other Any suitable heat transfer device can be used.

The present invention can be more fully and easily understood with reference to the accompanying drawings.

The method improved by the present invention allows for the reuse of used lubricating oil.
Provided by Sui. Thus, the method of the present invention is generally applicable to any used oil containing lubricating oil. In many cases, the most easily obtained used lubricants are used lubricants from machines, used lubricants from equipment, conductive fluids, and other fluids whose major component is oil of lubricating viscosity. Kikiri, 1i
II+ As used in snow, the preferred oils are petroleum-based oils (eg mineral oils), although synthetic oils can be substituted therein.

In general, the method of the present invention often requires diesel.

The following steps are included to treat used lubricating oil collected as waste fluid from gasoline engines and other types of internal combustion engines. The spent oil feedstock is distilled to remove water, gasoline, and other class 1 and above volatile components therefrom.

This first step is operated at or near atmospheric pressure;
This is not important. When the first step is operated at atmospheric pressure, the raw material O.1 is generally heated to a range between about 220F and about 400F. The optimum temperature for the first step is determined by the water and volatile fuel feed contaminants and the residence time provided to remove these components from the feed.

In the second step, the residue from the first step is then reduced to about 251
(approximately 121.1°C) and 500F (260°C).

The residue from the first step is then evaporated in a second step to remove the fuel oil fraction (heavier than that removed in the first step and slightly less volatile). The evaporation section is preferably operated at reduced pressure, generally in the range of about 20 to about 150 millimeters of absolute mercury. The preferred vacuum range and temperature are selected to remove all desired components such as fuel oil.

Generally 460FC (approximately 2677°C) and 500F (26
DC) with residual lubricating oil outlet temperature of about 15 mercury absolute
A pressure of 0 mm is generally required.

Preferably, the volatile pre-cut has a flash point of about 116°C or less.

The first two steps can be accomplished in a few minutes at this reduced pressure to remove all of the water, gasoline, and other volatile fuel components along with slightly less volatile components such as fuel oil, as described above. The spent oil is preferably distilled to remove the pre-distillate fraction, which has a viscosity less than that of the lubricating oil and a flash point below about 116°C. Obtained by I
WI i (gives a residual oil with R oil viscosity.

In the sixth step, removal of lubricating oil products first occurs. The process operates at pressures ranging between about 2 and 5 millimeters of mercury absolute and temperatures ranging between about 265°C (about 122.2°C) and 500°F (260°C).

These pressures and temperatures provide a recovery (recirculation rate of 1') of about 5 parts by weight and 56 parts by weight of each oil for a typical use lubricating oil. These variables are varied based on the evaporation characteristics of the feedstock as well as the operating conditions imposed on the sixth stage evaporator. Recirculation of the distillation product is used which substantially increases lubricant removal and further reduces the evaporation temperature. Generally, the viscosity of the oil removed in the sixth step is approximately 6 Q at 100F.
ssu and 200 ssu.

Recirculation of the vaporized product substantially increases lubricant recovery due to carrier and partial pressure effects. 1st
Listed in the table are representative feed logs ↓ 71 and 4 recycle numbers for 4 different overhead distillates (0%, 5
0%, 100% and 200%) based improvements and associated recovery agents. One major improvement obtained by distillate recycling is a reduction in the effective evaporation temperature of the feedstock. This increases recovery and lowers operating temperatures, with a significant reduction in the tendency for coking or cracking of the feedstock. Furthermore, the tendency for equipment to become contaminated is also reduced. It is important to understand the distinction between distillate reflux and recycling to more fully understand the present invention. The principle of reflux is to return the condensed product at the top of the evaporation column to the top or side of the column. The purpose of reflux is to improve fractionation. In contrast, distillate recirculation basically returns a portion of the condensed vapor to the feedstock, thereby reducing the evaporation temperature of the feedstock due to its partial pressure effect. can do.

Table 1 Amount of evaporated raw material, weight ratio 500F 700F 800F 820F Atmospheric evaporation temperature (260℃) (360℃) (approx. 426.
6℃) (approximately 437.7'C) Flash evaporation (feed material recirculation 0) 5.0 17.5 4
8.0 56650% recirculation 10.0 2
7.2 60.5 68.9 100% recirculation
17.4 Ro2.3 66.5 77.52
00% recirculation 22.4 36.2 70.
279.8 The values shown in Table 1 were obtained from the evaporation curve plotted in FIG.

Therefore, the combinations of pressures, temperatures, and recirculation ratios outlined in Table 1 yield lubricating oil distillates ranging from 5% to 798% by weight from the 6th stage to this stage for typical waste oils. . By adjusting specific parameters of pressure, temperature and recycle ratio, very specific product properties can be obtained at lower temperature operating conditions compared to systems without recycle. Additionally, if product recovery in the sixth step is desired without additional steps, the upper limit of recycle can be utilized to maximize recovery.

In the fourth step, the heavy lubricating oil fraction is converted into a very heavy viscous residue (generally about 6,000 to 35 mm at 210F).
0005SU) is removed as a product. The operation of the fourth step is similar to that of the sixth step in that the operating pressure, temperature and recirculation rate can be varied to produce heavy lubricants with different properties desired by different end users. Similar. In the fourth stage, the recycling of the vaporized product has the same effect as previously described for the sixth stage.

namely, increased recovery of lubricating oil products, lowered evaporation temperatures, and reduced risk of coking and cracking of the feedstock.

The operating conditions for the fourth step are generally about 0.5-3.0 millimeters of ice-silver absolute pressure and about 315 degrees Fahrenheit (about 168 degrees Fahrenheit).
4° C.) and 6007” (approximately 315.5° C.). Preferred operating conditions are approximately 0.5 mm!J meters of mercury absolute pressure and temperatures between 550° F. (approximately 2877° C.) and 650° F. (approximately 343° C.). 3° C.). However, as described above with respect to the filtration step, these conditions can be varied to alter the nature of the feedstock that is evaporated and recovered as product. The parameters of can vary depending on the type of feedstock.Generally, the viscosity of the lubricating oil obtained in the fourth step is 200 SSU and 12 D O5St at 100F (approximately 677C).
It's between J.

Recirculation of vaporized products increases recovery of heavy lubricating oils due to carrier or partial pressure effects.

Listed in Table 2 are four recycles (0%
, 50%, 100% and 200%) and associated recovery measures. One major improvement achieved by recirculation is a reduction in the effective evaporation temperature of the feedstock. This increases the recovery of the heavy lubricating oil distilled in the fourth step, while reducing the risk of coking, cracking and contamination.

Table 2 Flash evaporation (no recirculation) 16,4 40,5 62゜2
77550% recirculation 20.7 47.2 66
．． 9 78.0ioo% recirculation 22.7 51
．． 0 71.5 81.0200% recirculation 24
．． 0 52.7 73.9 82.7 The values listed in Table 2 were obtained from the evaporation curves listed in FIG. The ability to vary the recirculation rate with changes in pressure and temperature allows maximum recovery of heavy lubricating oil in step 4 of the method to be achieved.

In accordance with a preferred embodiment of the invention, the evaporation of steps 6 and 4 is carried out in a stirred thin film evaporator or mesh-film evaporator or any other suitable heat transfer device.

The method can be more fully understood by reference to FIG. 1, which is a schematic representation of a preferred embodiment of the method. The raw material for waste oil is line 1.
The liquid is pumped through 0 and heated by heat exchanger 12 to a temperature ranging between 100F and 2ooF. The feedstock then exits heat exchanger 12 and enters line 14.

The feed exits line 14 and enters a first stage evaporator 16 which generally operates near atmospheric pressure. In the first stage evaporator 16, the feedstock is heated at 200FC (approximately 104.4°C) and 400FC to remove all water, gasoline and other volatile components.
(approximately 204.4° C.). Water, gasoline and other volatile components removed from the feed are condensed through line 18 and cooled by heat exchanger 20. Water, gunlin and other volatiles removed from the feedstock are separated into fuel and water using conventional separation techniques. .

The oil leaving the first stage is pumped through line 22 and heated to 300'F (approximately 148.8°C) by heat exchanger 24.
00FC (approximately 204.4°C). After being heated in heat exchanger 24, the oil flows through line 26 to the second stage.

In the second step of the process, the oil is treated in a second stage evaporator 28. The second stage evaporator 28 is generally operated at a reduced pressure in the range of 20-150 milliJ meters of mercury absolute. The oil is heated to approximately 250F (approximately 121.1C) and 50 (IF) in the second stage.
0° C.). The second stage evaporator 28 removes heavier fuel oil components present in the waste oil that reaches the second stage by evaporation.

The heavier fuel removed at this stage is transferred to the second stage evaporator 2.
8 and passes through line 30, after which it is condensed and cooled in a heat exchanger. The oil not removed from the second stage passes through line filter 4 and exits the second stage evaporator. The oil in line filter 4 flows through line filter 5, is heated in heat exchanger filter 6, exits heat exchanger 36, and enters line filter 8. The oil then returns to stage 6 40 for processing. In the heat exchanger 36 the oil is generally about 6
50F (approximately 176.6°C) and 450F (approximately 232.6°C).
2° C.).

As mentioned above, the sixth stage evaporator 40 is utilized and typically has a
FC (about 1294° C.) and 500° F. (260° C.) and vacuum pressures ranging between about 2 and 5 millimeters of mercury absolute. The light lubricating oil is evaporated in the third stage evaporator 40 and exits to line 42.

The line 42 sends the evaporated light lubricating oil to a heat exchanger 44, where the evaporated light lubricating oil is condensed and cooled to substantially the same temperature as the line filter 4. This resulting light lubricating oil product then exits heat exchanger 44 and enters line 46. Line 46 is separated into two separate lines 48 and 50. Separation in line 46 forms a recycle of light lubricating oil to mix with the product of line 34 and pass through line 48 and then line 65 as a charge to stage six. Therefore line 4
It is necessary to have suitable valves or other equipment to be able to achieve the desired separation of 6. Light lubricating oil entering line 48 is recycled oil and mixed with waste oil exiting line 64 to produce line 65.

The desired recirculation rate of line 48 relative to line 34 is a regulated flow rate determined by the desired operating parameters. Preferably, the fluid in line 48 can vary from about 0 to about 00% by weight of the fluid in line 64. Therefore line 3
Raw materials No. 5 and No. 38 consist of blends from line filters No. 4 and No. 48. For example, if 100% recirculation is desired, the fluid volume in line 64 is equal to the fluid volume in line 48. The light lubricating oil forming line 50 is further cooled in a heat exchanger 52.

The residual product of the third stage evaporator exits the sixth stage evaporator 40 and enters line 54 where it is mixed with line 56 to form line 58 which enters heat exchanger 60 . Line 56 is the fourth
Line 58 at heat exchanger 60, which is the recirculation line for the stage evaporator.
The product of about 400F and 490
It is heated to a temperature range between F (approximately 254.4 C). The product then exits heat exchanger 60 and enters line 62 which is fed to a fourth stage evaporator 64. The fourth stage evaporator typically has vacuum pressures in the range of about 0.5 and 3 millimeters of mercury absolute and about 315F (about 157.2'C) and
62.2°C). The heavy lubricating oil evaporated in the fourth stage is transferred to the fourth stage wipe-film evaporator 64.
It passes through line 66 and is condensed and cooled by heat exchanger 68 to a temperature substantially the same as that of line 54. This product of heavy lubricating oil is directed to line 70 which is separated into two lines, lines 56 and 72. 6th
The desired circulation rate is determined by the flow rates in lines 56 and 54, as discussed above with respect to stages. These are regulated flow rates determined by the desired operating conditions.

Preferably, the flow rate in line 56 can vary from about 0 to about 600 parts by weight, depending on the flow rate in line 54. This fluid, which does not require recirculation, is then slightly cooled in heat exchanger 74 and transferred via line 76 to storage awaiting further processing or use. The residual product of the fourth stage is transferred to the fourth stage evaporator 64.
and enters line 78 where it is transferred to storage.

In order to achieve an industrial lubricating oil with characteristics close to, equal to, or better than a clean lubricating oil, steps of polishing the colored pool and removing impurities remaining in the heavy and light oils are necessary. For example, U.S. Patent No. 4.302.325
A method such as that described in No.

Although the invention has been described with respect to preferred uses, various modifications thereof that will now become apparent to those skilled in the art are considered to be within the scope of the appended claims.

[Brief explanation of drawings]

FIG. 1 is a flow sheet of the preferred method and a schematic diagram of the equipment utilized in connection with the present invention. FIG. 2 is a graph illustrating the effect of circulation ratio on the amount of used oil evaporated as a function of ambient temperature for the evaporation of a representative waste oil excluding water and volatile pre-distillates according to the present invention. FIG. 6 is a graph representing the effect of circulation ratio on the function of atmospheric temperature on the evaporation of the heavy fraction obtained according to the invention and on the amount of used oil evaporated at 1. Patent Applicant Delta Central Refining
(Geto 2 people)

Claims (1)

Claims: 1. (a) Provides a lubricating oil-containing oil obtained by removing volatile pre-distillates from used oil. (1)) Evaporate the resulting oil to produce a heavy fraction and a light fraction, and evaporate a portion of the light fraction in an amount effective to reduce the evaporation temperature prior to evaporation of the resulting oil. A method for refining used oil containing lubricating oil characterized by steps that are mixed into the resulting oil by circulation to reduce the tendency to coking and cracking during evaporation. 2 A view of the circulating light distillate is approximately 5 Ft of the obtained oil.
% and 300% by weight. 3. The method of claim 1, further comprising evaporating a heavy fraction obtained from evaporation of the resulting oil to form a heavy lubricating oil fraction and a residual fraction. 4. The method of claim 2, wherein a portion of the heavy lubricating oil fraction is recycled and mixed into the heavy fraction before its evaporation. 5. A method according to claim 1, in which the resulting oil is evaporated in a stirred thin film evaporator. 6. Wipe off the resulting oil and evaporate the film.
7. The method according to claim 6, in which the heavy fraction is evaporated in a stirred thin film evaporator. 8. The heavy fraction is evaporated in a stirred thin film evaporator. 9. The process of claim 6 wherein substantially all of the water, gutulin and other similar volatile components are evaporated in a wiping sea film evaporator. 10. The method of claim 1, wherein the volatile pre-distillate has a drawdown point of about 116° C. or less. Process. 11. The removal in step (a) of claim 1 is carried out under reduced pressure and at about 250F (about 121C) and 500F.
9. A method according to claim 1 or claim 8, which is carried out at a temperature between 0F (260C). 12, vacuum is absolute 20 mm of mercury and 150 mm
2. A method according to claim 1, wherein the diameter is between millimeters. 13, the process of claim 1 (evaporation in bl is under reduced pressure and about 265FC about 1294°C) and 500
2. A process according to claim 1, which is carried out at a temperature between F (260<0>C). 14. The method as claimed in claim 12, wherein the reduced pressure is between 2 and 5 millimeters of mercury absolute. 15. A process according to claim 1, wherein the ratio of the oil obtained to the light fraction recycled into the oil obtained is 4:1. 16. (a) removing volatile pre-distillates from a used oil to provide a lubricating oil-containing oil; (b) evaporating the resulting oil under reduced pressure in an agitated thin film evaporator; (C) evaporating the heavy fraction obtained from evaporation of the resulting oil under reduced pressure to separate the heavy fraction and the residual fraction; Recycling of used lubricating oil characterized by each process; Sui manufacturing method. 17. The method according to claim 16, wherein the heavy fraction is evaporated by a wipe-film evaporator. 18. The method according to claim 16, wherein the heavy fraction is evaporated in a stirred thin film evaporator. 19. The method of claim 16, wherein the volatile pre-cut has a flash point of about 116°C or less. 2. Claim 16 The removal in step (a) is performed at approximately 250F (approximately 121°C) and 500F (approximately 260°C).
17. The method of claim 16, wherein the method is carried out at a temperature between .degree. 21, the vacuum is 20 mm of absolute mercury and 15
21. The method of claim 20, wherein the range is between 0 and IJ meters. 22 In used lubricant refining processes where it is desirable to modify the range of lubricant evaporated in the evaporation process, the used lubricant is evaporated to produce heavy and light fractions, and the evaporation of the used lubricant is (Prior to the evaporation period, a portion of said light distillate is introduced into the used oil in an effective amount to reduce the evaporation temperature to a desired level such as to reduce the tendency of coking and cracking of the used oil during the evaporation period.) A method characterized by circulating and mixing to evaporate a desired number of waste oil feedstocks.23.In a method for refining used lubricating oils, coking, cranking and fouling tendencies are eliminated while maximizing recovery while maturing. The method comprises the steps of evaporating used lubricating oil to produce heavy and light fractions, evaporating a desired amount of used lubricating oil feedstock before evaporating the used oil;
A process characterized in that a portion of the light fraction is recycled and mixed into the used oil in an amount effective to simultaneously lower the effective evaporation temperature of the feedstock. 24. In the process of refining used lubricating oils, the method of reducing the evaporation temperature of used lubricating oils and reducing the tendency to coking, cracking and fouling is to evaporate the used lubricating oils in an evaporator and produce heavy and a step of producing a light fraction, wherein an effective amount of a portion of the light fraction is used to evaporate the desired amount of used lubricating oil feedstock and reduce its effective evaporation temperature prior to evaporation of the used oil. A method characterized by circulating and mixing into the used oil.