A method and apparatus for re-refining used oil, in which the used oil is processed in at least one cyclonic vacuum evaporator comprising a void evaporation chamber (4) into which feedstock is tangentially injected, and in which a fraction of the feedstock is condensed in a spray condenser (7) communicating with the evaporation chamber (4).

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Patent
   RE38366
Priority
Jun 08 1995
Filed
Sep 19 2000
Issued
Dec 30 2003
Expiry
Jun 07 2016
Inventors
Kenton, Ka…
Assg.orig
Avista Res…
Assg.curr
Avista Res…
Entity
unknown
Referenced by
11
References
15
Maint.:
EXPIRED
DETAILED DESCRIPTION…
0. 13. A method of re-fining used oil wherein the used oil is processed in at least one cyclonic vacuum evaporator, the cyclonic vacuum evaporator comprising an evaporation chamber which is substantially free of moving parts and/or labyrinthine structures, said method comprising
(a) tangentially injecting a primary feedstock into a first evaporator, the first evaporator having a temperature of from 160 to 180°C C. and a pressure of from 400 mbar to atmospheric, wherein a fraction of the feedstock is condensed in a spray condenser communicating with the first evaporation chamber, and a further fraction of the feedstock is collected as a first bottoms product at a lower end of the first evaporating chamber;
(b) tangentially injecting a proportion of the first bottoms product into a second evaporator, the second evaporator having a temperature of from 260 to 290°C C. and a pressure of from 40 to 100 mbar vacuum, wherein a fraction of the first bottoms product is condensed in a spray condenser communicating with the second evaporation chamber, and a further fraction of the first bottoms product is collected as a second bottoms product at a lower end of the second evaporation chamber;
(c) tangentially injecting a proportion of the second bottoms product into a third evaporator having a temperature of from 290 to 330°C C. and a pressure of from 15-25±10
% mbar vacuum, wherein a fraction of the second bottoms product is condensed in a spray condenser communicating with the third evaporation chamber, and a further fraction of the second bottoms product is collected as a third bottoms product at a lower end of the third evaporation chamber; and
(d) tangentially injecting a proportion of the third bottoms product into a fourth evaporator having a temperature of from 320 to 345°C C. and a pressure of from 5 to 15 mbar vacuum, wherein a fraction of the third bottoms product is condensed in a spray condenser communicating with the fourth evaporation chamber, and a further fraction of the third bottoms product is collected as a fourth bottoms product at a lower end of the fourth evaporation chamber.
0. 1. A method of re-refining used oil wherein the used oil is processed in at least one cyclonic vacuum evaporator comprising a substantially void evaporation chamber into which feedstock is substantially tangentially injected, and wherein a fraction of the feedstock is condensed in a spray condenser communicating with the evaporation chamber.
0. 2. A method according to claim 1, wherein a portion of the feedstock is recirculated to the evaporation chamber at a higher temperature and a greater flow rate than the original feedstock by way of a recirculation circuit including a pump and a heater.
0. 3. A method according to claim 2, wherein distillate obtained from the spray condenser is recirculated to the spray condenser by way of a recirculation circuit including a pump and a heater.
0. 4. A method according to claim 1, wherein distillate obtained from the spray condenser is recirculated to the spray condenser by way of a recirculation circuit including a pump and a heater.
0. 5. A cyclonic vacuum evaporator provided with temperature and pressure control and comprising a substantially void evaporation chamber, means for injecting feedstock substantially tangentially into said evaporation chamber, and a spray condenser in communication with said evaporation chamber in which a distillate is obtained.
0. 6. An evaporator as claimed in claim 5, further comprising a feedstock recirculation circuit including a pump and a heater for recirculating the product collected at the bottom of said evaporation chamber back into said evaporating chamber.
0. 7. An evaporator as claimed in claim 6, wherein the evaporator is provided with a distillate recirculating circuit including a pump and a heater.
0. 8. An evaporation according to claim 6 wherein said feedstock injected into said evaporator has a first temperature and wherein said heater heats the recirculated product to a temperature higher than the temperature of the original feedstock.
0. 9. An evaporator as claimed in claim 5, further comprising a distillate recirculation circuit including a pump and a heater.
0. 10. A plant suitable for re-refining used oil, the plant comprising at least two cyclonic vacuum evaporators each provided with temperature and pressure control and each comprising a substantially void evaporation chamber into which, in use, feedstock is substantially tangentially injected, and each being provided with a spray condenser in communication with the evaporation chamber in which spray condenser a distillate may be collected, wherein the evaporators are linked together such that feedstock which has been processed in a first evaporator may be passed as feedstock to the at least one other evaporator for further processing.
0. 11. A plant as claimed in claim 10, wherein each evaporator and its associated spray condenser comprises a modular unit mounted in a frame.
0. 12. A cyclonic vacuum evaporator provided with a temperature and pressure control and comprising an evaporation chamber defining an interior space substantially void of baffles or other means to impart a cyclonic motion to the feedstock, means for injecting feedstock substantially tangentially into said evaporation chamber, and a spray condenser in communication with said evaporation chamber in which a distillate is obtained.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, feedstock used oil passes through a filter 1 and a pump 2 before being heated to the required temperature in a heat exchanger 3, from which it then passes to the cyclonic evaporator 4 by way of a flowmeter 5 which controls a valve 6 so as to regulate the flow of feedstock. The feedstock is then tangentially injected into the evaporator 4, in which predetermined temperature and pressure conditions are applied. Since the pressure in the evaporator 4 is less than atmospheric pressure, a predetermined fraction of the feedstock will be flashed off and pass upwards through a spray condenser 7, while the remaining fractions will fall to the bottom of the evaporator to form the bottoms product 8. The bottoms product 8 is recirculated by way of a pump 9 and a heat exchanger 10 to the evaporator 4. A temperature sensor 11 controls a valve 12 in the thermal oil supply 13 to the heat exchanger 10, thereby enabling control over the temperature of the recirculating bottoms product 8. A level controller 14 in the evaporator 4 controls a valve 15 which allows a proportion of the recirculating bottoms product 8 to be passed on for further processing as the bottom of the evaporator 4 fills up.

Part of the vapour fraction evaporated from the feedstock tangentially injected into the evaporator 4 is condensed in the spray condenser 7. This distillate is recirculated to the spray head 16 by way of a holding tank 17, a pump 18 and a heat exchanger 19. The cooling water input to the heat exchanger 19 is controlled by a temperature sensor 20 connected to the spray condenser 7, thereby enabling control of the temperature in the spray condenser to be achieved. A level controller 33 in the holding tank 17 controls a valve 21 which allows a proportion of the recirculating distillate to be fed to storage.

The vapour fraction which is not condensed in the spray condenser 7 passes to a subsequent condenser 22. The liquid fraction condensed in the condenser 22 is recirculated by way of a holding tank 23, a pump 24 and a heat exchanger 25. The cooling water input to the heat exchanger 25 is controlled by a temperature sensor 26 connected to the condenser 22, thereby enabling control of the temperature in the condenser to be achieved. A level controller 34 in the holding tank 23 controls a valve 27 which allows a proportion of the recirculating distillate to be fed to storage.

The vapour fraction which is not condensed in the condenser 22 passes to a vacuum system comprising two pumps 28 and 29, a cooler 30 and a holding tank 31. The primary function of the vacuum system is to maintain the vacuum in the main evaporator 4. A distillate produced in the vacuum circuit may be fed to storage, while the remaining vapour fraction may be fed through pipe 32 for incineration.

FIG. 2 shows four interconnected evaporator stages similar to that shown in FIG. 1. In the first stage, water and some light ends are obtained in the spray condenser 7, while further light ends are obtained in the secondary condensation circuit 35. The evaporator 4 of the first stage may operate at a temperature of 160°C to 180°C C. and a pressure of 400 mbar vacuum to atmospheric pressure. A proportion of the bottoms product of the first stage is passed on to the second stage for further processing. In the second stage, the evaporator 4' is operated at a temperature of 260°C to 290°C C. and a pressure of 40 to 100 mbar vacuum. Light oil and light fuel oil are condensed in the spray condenser and gas oil is condensed in the secondary condensation circuit 35'. The bottoms product of the second stage is fed to the third stage, where the evaporator 4" is operated at a temperature of 290°C to 330°C C. and a pressure of 15 to 25 mbar vacuum. 150 SN base oil distillate is obtained in the spray condenser and 100 SN base oil distillate in the secondary condensation circuit 35". Finally, the bottoms product of the third stage is fed to the fourth stage, where the evaporator 4'" is operated at a temperature of 320°C to 345°C C. and a pressure of 5 to 15 mbar vacuum. 350+ SN base oil distillate is obtained in the spray condenser and 250 SN base oil distillate in the secondary condensation circuit 35'". The various base oil distillates are stored at 36, from where they may be passed blockwise for finishing treatment.

FIG. 3 shows a re-refining plant in which each evaporator 4 and its associated ancillary apparatus, such as condensers 22 and 37, is mounted in a frame 38 so as to form a modular unit, indicated generally at 39. Input and output to each modular unit is arranged so that two or more modular units may be brought together and interconnected to a straight-forward manner, thereby allowing a plant to be built up quickly and simply. FIG. 4 is an end elevation of the plant of FIG. 3.

The following tables give the results, respectively, of an analysis performed on used lubricating oil, on base oil distillate produced from the used oil by an embodiment of the present invention, and on rerefined base oil to which a finishing treatment has been applied:

TABLE 1
Sample: Used Oil
Result Unit Method
Chlorine 710 mg/kg IP AK/81
Density 893.5 kg/m3 NF M 60-172
Metals: mg/kg ICP
Aluminium 16
Antimony 9
Barium 31
Cadmium 1
Calcium 2119
Chromium 3
Copper 37
Iron 108
Lead 214
Magnesium 274
Manganese 2
Molybdenum 4
Nickel 2
Silicium 45
Silver <1
Tin 10
Titanium 2
Vanadium 1
Zinc 904
Phosphorus 842 mm/kg ICP
Sulphur 0.648 mass % ASTM D 2622 (RX)
TAN 2.5 mg KOH/g NFT 60-112
Viscosity:
@40°C C. 71.44 mm2/s NFT 60-100
@100°C C. 11.64 mm2/s NFT 60-100
Water 4.0 mass % NFT 60-113
TABLE 2
Sample: Used Oil Distillate
Result Unit Method
Chlorine 42 mg/kg IP AK/81
Colour <7.5 Quotation NF T 60-104
Metals: mg/kg ICP
Aluminium 1
Antimony <1
Barium <1
Cadmium <1
Calcium 1
Chromium <1
Copper <1
Iron <1
Lead 1
Magnesium <1
Manganese <1
Molybdenum <1
Nickel <1
Silicium 8
Silver <1
Tin <1
Titanium <1
Vanadium <1
Zinc <1
Nitrogen:
Basic 92 mg/kg LPMSA/718
Total 329 mg/kg LPMSA/652
Phosphorus 36 mg/kg ICP
Sulphur 0.419 mass % ASTM D2622 (RX)
TAN 0.15 mg KOH/g NFT 60-112
Viscosity:
@40°C C. 31.07 mm2/s NFT 60-100
@100°C C. 5.349 mm2/s NFT 60-100
Viscosity:
Index 105 Quotation NFT 60-136
TABLE 3
Sample: Re-refined Base Oil
Result Unit Method
Chlorine 3 mg/kg IP AK/81
Colour <1.5 Quotation NF T 60-104
Metals: mg/kg ICP
Aluminium <1
Antimony <1
Barium <1
Cadmium <1
Calcium <1
Chromium <1
Copper <1
Iron <1
Lead <1
Magnesium <1
Manganese <1
Molybdenum <1
Nickel <1
Silicium <1
Silver <1
Tin <1
Titanium <1
Vanadium <1
Zinc <1
Nitrogen:
Basic 10 mg/kg LPMSA/718
Total 31 mg/kg LPMSA/652
Phosphorus <1 mg/kg ICP
Sulphur 0.300 mass % ASTM D2622 (RX)
TAN <0.05 mg KOH/g NFT 60-112
Viscosity:
@40°C C. 29.25 mm2/s NFT 60-100
@100°C C. 5.16 mm2/s NFT 60-100
Viscosity
Index 105 Quotation NFT 60-136
Cloud Point -7 °C C. NF T 60-105
Conradson Carbon
Residue <0.01 mass % ASTM D 189
Distillation (GC) °C C. ETS 83-001
IBP 299
5 366
10 385
15 396
20 404
30 416
40 426
50 434
60 443
70 452
80 463
85 470
90 479
95 490
FBP 521
Flash Point
COC 218 °C C. NFT 60-118
Noack Volatility
(1 hr @ 250°C C.)14.3 mass % NF T 60-161
Oxidation Stability
(2 × 6 hrs @ 200°C C.): IP 48
Viscosity @ 40°C C.:
before 29.25 mm2/s NF T 60-100
after 36.28 mm2/s NF T 60-100
Conradson Carbon Residue:
before <0.01 mass % ASTM D 189
after 0.37 mass % ASTM D 189
Pour Point -12 °C C. NF T 60-105
INVENTORS:

Kenton, Kalevi John

THIS PATENT IS REFERENCED BY THESE PATENTS:
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10287513, Mar 07 2013 REGEN III CORP Method and apparatus for recovering synthetic oils from composite oil streams
10287514, Mar 07 2013 REGEN III CORP Method and apparatus for recovering synthetic oils from composite oil streams
6958107, Sep 30 1998 Alcos Technologies Pty Ltd Cyclonic evaporator
7150822, Sep 04 2003 DTX Technologies LLC Five degrees for separation
7241377, Sep 04 2003 DTX Technologies, LLC Salt bath refining
7767170, May 21 2004 ExxonMobil Chemical Patents Inc. Cracking hydrocarbon feedstock containing resid utilizing partial condensation of vapor phase from vapor/liquid separation to mitigate fouling in a flash/separation vessel
7993435, May 21 2004 ExxonMobil Chemical Patents Inc. Process and apparatus for cracking hydrocarbon feedstock containing resid
8366912, Mar 08 2005 REGEN III CORP Method for producing base lubricating oil from waste oil
8936718, Mar 08 2005 REGEN III CORP Method for producing base lubricating oil from waste oil
9512369, Mar 14 2013 James Joseph, Noble; NOBLE, JAMES JOSEPH Process for removing color bodies from used oil
9677013, Mar 07 2013 REGEN III CORP Method for producing base lubricating oil from oils recovered from combustion engine service
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