TREA

Method for the determination of the oxidative stability of a lubricating fluid

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Information

  • Patent Application
  • 20080090296
  • Publication Number
    20080090296
  • Date Filed
    October 11, 2006
    18 years ago
  • Date Published
    April 17, 2008
    16 years ago
Information
Abstract
The present invention concerns a method for the determination of the oxidative stability of a lubricating fluid, comprising the steps of:
Description
EXAMPLE 1

A closed reaction cell for oxidative conditions has been prepared by setting the velocity of flow to about 56.66 liter per minute at a given vacuum target of about 0.061 MPa (face velocity created by a vacuum pressure of 0.061 MPa), once set; the cell has been reopened. The valve configuration to collect the liquid nitrogen dioxide from the lecture bottle to the graduated glass tube has been set. The valve configuration has been reset back to reactor for nitrogen dioxide gas delivery. In a glass beaker 200.0 grams of the formulated oil as mentioned in the following tables with 15 ppm iron catalyst (Iron ferrocene) based on oil weight has been weighted and mixed in beaker. The mix of oil and catalyst has been charged to the reaction cell, agitation has been started and the reaction cell has been closed. The cell has been brought to reduced pressure (already set), the air flow has been adjusted to about 185 milliliters per minute and timer has been set to the specified reaction time of about 40 hours. The temperature controller has been set to heat the reaction to 170° Celsius and the nitrogen dioxide feed has been adjusted to deliver gas over 12 hours at a flow rate of about 0.16 milliliters per hour. The total weight of nitrogen dioxide delivered to the cell was 2.886 grams (1.443% by weight).


The test results of ASTM Reference Oils 438, 435 and 434 are mentioned in the following tables I, II and III,









TABLE I







Comparison of MRV TP-1 viscosity and Kinematic viscosity increase @


40° Celsius from the Sequence IIIG and Laboratory Reactor Aged Oils










% Viscosity Increase @
MRV TP-1 Ys, Pa/Viscosity,


Sample
40° Celsius
cP










ASTM Oil 438 Sequence IIIG Engine









1
88.0
No/16,700


2
90.0
No/18,000


3
91.0
No/19,000


4
94.8
No/19,300


5
99.4
No/20,500


6
104.7
No/20,500


7
109.5
No/23,700


8
115.1
No/30,400







ASTM Oil 438 Laboratory Reactor









1
74.0
No/16,570


2
101.0
No/14,100


3
109.0
No/21,120


4
113.0
No/26,400


5
127.0
No/30,000


6
133.0
No/29,800


7
152.0
No/27,300
















TABLE II







Comparison of MRV TP-1 viscosity and Kinematic viscosity increase @


40° Celsius from the Sequence IIIG and Laboratory Reactor Aged Oils












% Viscosity Increase @
MRV TP-1 Ys, Pa/



Sample
40° Celsius
Viscosity, cP











ASTM Oil 435 Sequence IIIG Engine











1
163.0
Yes/84,800



2
168.0
Yes/110,100



3
172.0
Yes/84,500



4
176.0
Yes/91,900



5
222.0
Yes/300,200



6
230.0
Yes/294,000



7
279.0
Yes/210,700



8
305.0
Yes/400,000







ASTM Oil 435 Laboratory Reactor











1
185.0
Yes/99,300



2
226.0
Yes/83,500



3
256.0
Yes/182,800



4
310.0
Yes/85,400

















TABLE III







Comparison of MRV TP-1 viscosity and Kinematic viscosity increase @


40° Celsius from the Sequence IIIG and Laboratory Reactor Aged Oils










% Viscosity Increase @
MRV TP-1 Ys, Pa/Viscosity,


Sample
40° Celsius
cP










ASTM Oil 434 Sequence IIIG Engine









1
63.0
No/29,000


2
87.0
No/34,200


3
90.0
No/31,900


4
99.0
No/45,600


5
127.0
No/49,200


6
133.0
No/48,900


7
250.0
No/86,400







ASTM Oil 434 Laboratory Reactor









1
57.0
No/30,000


2
59.0
No/32,500


3
94.0
No/43,300


4
118.0
No/48,000


5
122.0
No/57,600








Claims
  • 1. A method for the determination of the oxidative stability of a lubricating fluid, comprising the steps of: introducing a sample of the lubricating fluid under test in an reaction cell;introducing catalytic amounts of a catalyst to the reaction cell;heating the cell to the oxidation temperature of the lubricating fluid and maintaining this temperature;delivering a gas comprising oxygen at constant flow rate through the cell over the course of the reaction;delivering a gas comprising nitrogen dioxide at a constant flow rate through the cell for a specified time;applying and maintaining a specified vacuum on the reaction cell;allowing the mixture to react for a specified time;measuring the viscosity of the oxidized lubricating fluid.
  • 2. The method according to claim 1 wherein the oxidation temperature is in the range of 160° C. to 180° C.
  • 3. The method according to claim 1 or 2 wherein the specified time for allowing the mixture to react is in the range of 30 to 50 hours.
  • 4. The method according to at least one of the preceding claims wherein the nitrogen dioxide flow is in the range of 0.15 to 0.18 milliliters per hour over 11 to 13 hours.
  • 5. The method according to a least one of the preceding claims wherein flow of the gas containing oxygen is in the range of 180 to 190 milliliters per minute throughout the reaction.
  • 6. The method according to at least one of the preceding claims wherein the heating of the cell is performed under a reduced pressure.
  • 7. The method according to at least one of the preceding claims wherein the delivering of the gas is performed under a reduced pressure.
  • 8. The method according to claim 5 or 6 wherein the reduced pressure of the specified vacuum is in the range of 0.061 to 0.063 MPa.
  • 9. The method according to at least one of the preceding claims wherein the total amount of nitrogen dioxide delivered to the reaction cell is in the range of 1 to 2% by weight based on the total amount of lubricating fluid at the start of the test.
  • 10. The method according to at least one of the preceding claims wherein iron ferrocene is used as catalyst.
  • 11. The method according to at least one of the preceding claims wherein iron ferrocene is added to the reaction mixture at 10 to 20 ppm based on the lubricating fluid charge.
  • 12. The method according to at least one of the preceding claims wherein the Mini-Rotary Viscosity of the lubricating fluid is measured according to ASTM D 4684.
  • 13. The method according to at least one of the preceding claims wherein the increase of the kinematic viscosity at 40° C. of the lubricating fluid is measured according to ASTM D 445.
  • 14. The method according to at least one of the preceding claims wherein the lubricating fluid is an engine oil lubricant or a transmission or a hydraulic fluid.
  • 15. An apparatus to perform the method according to at least one of the claims 1 to 14 comprising a reaction cell with an integral heating element for containing a sample of the lubricant;means for heating the cell to the oxidation temperature of the lubricant;means for mixing the lubricant;means for bubbling a gas comprising oxygen at a constant flow rate in subsurface feed through the cell;means for bubbling nitrogen dioxide gas at a constant flow rate in subsurface feed through the cell for a specified time;means for reducing pressure of the cell at a constant flow rate and collecting the resulting distillate;means of introducing catalytic amounts of a catalyst to the lubricant;means of measuring nitrogen dioxide liquid;means of measuring and controlling elapsed time of the reaction.
  • 16. The apparatus according to claim 15 wherein the reaction cell with an integral heating element includes: a stainless steel flat head with various threaded ports;a packing gland housing for providing a seal around the agitator shaft;rods to support the head and cell to a laboratory hood framework;a clamp to connect the cell to the head.
  • 17. The apparatus according to claim 15 or 16 wherein the heating means includes: a temperature-controller with an on/off algorithm for maintaining reaction temperature;a J-thermocouple sensor;a voltage controller for maintaining low voltage to cell heating element.
  • 18. The apparatus according to at least one of the claims 15 to 17 wherein the mixing means includes: an electric motor capable of maintaining constant revolutions per minute;a stainless steel 45° pitched blade stiffer.
  • 19. The apparatus according to at least one of the claims 15 to 18 wherein the bubbling oxygen containing gas means includes: an oxygen gas supply capable of maintaining constant flow;a flow meter for measuring the flow rate of the oxygen containing gas;a gas drying jar for filtering moisture from the oxygen containing gas;a high temperature tube positioned to bottom of cell.
  • 20. The apparatus according to at least one of the claims 15 to 19 wherein the bubbling nitrogen dioxide gas means includes: a glass graduated tube to measure the flow rate of nitrogen dioxide;a stainless steel metering valve to maintain a constant flow of nitrogen dioxide to the oxygen containing gas bubbling tube.
  • 21. The apparatus according to at least one of the claims 15 to 20 wherein the reduced pressure at a constant flow rate and distillate collection means includes: a vacuum pump with sufficient capacity to achieve a constant flow at reduced pressure with a closed cell;a flow meter to measure the flow rate of the oxygen containing gas;a stainless steel needle valve to control the flow rate of the oxygen containing gas;a condenser of correct size to limit pressure drop and collect distillate and means of recovering the distillate.
  • 22. The apparatus according to at least one of the claims 20 to 21 wherein means of introducing a catalyst includes: analytical balance capable of weighing to the nearest 0.0001 gram.
  • 23. The apparatus according to at least one of the claims 15 to 22 wherein measuring is nitrogen dioxide liquid means include: a stainless steel ball valve to vent system when apparatus is disconnected;a stainless steel needle valve to control the flow of liquid nitrogen dioxide;a glass tube;a 3-way plug valve to direct liquid nitrogen dioxide to tube or nitrogen dioxide gas to cell;a metering pump to evacuate nitrogen dioxide from graduated glass tube.
  • 24. The apparatus according to at least one of the claims 15 to 23 wherein measuring and controlling elapsed time of the reaction means include: a sixty hour count down time controller.