U.S. patent application number 10/983839 was filed with the patent office on 2006-05-11 for cycloalkane base oils, cycloalkane-base dielectric liquids made using cycloalkane base oils, and methods of making same.
Invention is credited to Steven Allen Holmes, John Robert Powers, Michael Phillip Smith.
Application Number | 20060100466 10/983839 |
Document ID | / |
Family ID | 36317218 |
Filed Date | 2006-05-11 |
United States Patent
Application |
20060100466 |
Kind Code |
A1 |
Holmes; Steven Allen ; et
al. |
May 11, 2006 |
Cycloalkane base oils, cycloalkane-base dielectric liquids made
using cycloalkane base oils, and methods of making same
Abstract
Cycloalkane base oil, methods of making cycloalkane base oil,
and dielectric liquid containing such cycloalkane base oil is
provided. The cycloalkane base oil contains a quantity of
isoparaffins and from 50 wt. % to 70 wt. % cycloalkanes having the
formula C.sub.nH.sub.2n wherein n is from 15 to 30, the quantity of
isoparaffins being less than 50 wt. % of said cycloalkane base
oil.
Inventors: |
Holmes; Steven Allen;
(Houston, TX) ; Powers; John Robert; (Kingwood,
TX) ; Smith; Michael Phillip; (The Woodlands,
TX) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
36317218 |
Appl. No.: |
10/983839 |
Filed: |
November 8, 2004 |
Current U.S.
Class: |
585/1 ; 508/563;
508/586 |
Current CPC
Class: |
Y10T 428/25 20150115;
Y10T 428/24901 20150115; C10M 105/04 20130101; C10M 169/04
20130101; C10N 2030/06 20130101; C10M 2203/1065 20130101; C10N
2030/52 20200501; Y10T 428/31678 20150401; C10N 2030/04 20130101;
C10M 2203/045 20130101; C10M 2203/06 20130101; C10N 2020/071
20200501; C10M 2205/22 20130101; C10M 2207/026 20130101 |
Class at
Publication: |
585/001 ;
508/563; 508/586 |
International
Class: |
C10M 105/04 20060101
C10M105/04 |
Claims
1. A cycloalkane base oil comprising a quantity of isoparaffins and
from 50 wt. % to 70 wt. % cycloalkanes having the formula
C.sub.nH.sub.2n wherein n is from 15 to 30, said quantity of
isoparaffins being less than 50 wt. % of said cycloalkane base
oil.
2. The cycloalkane base oil of claim 1 comprising from about 20 wt.
% to about 40 wt. % isoparaffins.
3. The cycloalkane base oil of claim 1 wherein a majority of the
cycloalkanes comprise alkyl-substituted cycloalkanes.
4. The cycloalkane base oil of claim 2 wherein a majority of the
cycloalkanes comprise alkyl-substituted cycloalkanes.
5. The cycloalkane base oil of claim 3 boiling at a temperature in
the range of from about 260.degree. C. (500.degree. F. ) to about
371.degree. C. (700.degree. F. ).
6. The cycloalkane base oil of claim 4 boiling at a temperature in
the range of from about 260.degree. C. (500.degree. F. ) to about
371.degree. C. (700.degree. F. ).
7. The cycloalkane base oil of claim 6 comprising about 15 ppm
sulfur or less.
8. The cycloalkane base oil of claim 3 wherein 70 wt. % or more of
the cycloalkanes comprise said alkyl-substituted cycloalkanes.
9. The cycloalkane-base oil of claim 5 wherein 80 wt. % or more of
the cycloalkanes comprise said alkyl-substituted cycloalkanes.
10. The cycloalkane base oil of claim 5 wherein 90 wt. % or more of
the cycloalkanes comprise said alkyl-substituted cycloalkanes.
11. The cycloalkane base oil of claim 6 wherein 70 wt. % or more of
the cycloalkanes comprise said alkyl-substituted cycloalkanes.
12. The cycloalkane base oil of claim 6 wherein 90 wt. % or more of
the cycloalkanes comprise said alkyl-substituted cycloalkanes.
13. The cycloalkane base oil of claim 7 wherein 99 wt. % or more of
the cycloalkanes comprise said alkyl-substituted cycloalkanes.
14. A cycloalkane-base dielectric liquid comprising cycloalkane
base oil comprising a quantity of isoparaffins and from 50 wt. % to
70 wt. % cycloalkanes having the formula C.sub.nH.sub.2n wherein n
is from 15 to 30, said quantity of isoparaffins being less than 50
wt. % of said cycloalkane base oil; and, one or more non-phenolic
alkyl substituted or partially saturated aromatic anti-gassing
agent comprising at least one labile hydrogen atom, said quantity
being effective to reduce the gassing tendency of the dielectric
liquid.
15. The cycloalkane-base dielectric liquid of claim 14 further
comprising an amount of one or more antioxidant selected from the
group consisting of hindered phenols, cinnamate type phenolic
esters, and alkylated diphenylamines, said amount being effective
to reduce sludge formation and total acid number in mg of KOH/g
(TAN) under oxidation conditions.
16. The cycloalkane-base dielectric liquid of claim 14 further
comprising an oxidation reducing amount of one or more antioxidant
selected from the group consisting of 2,6-ditertiary-butyl
para-cresol, 2,6-ditertiary butylphenol, and combinations thereof,
said amount being effective to reduce sludge formation and total
acid number (TAN) under oxidation conditions.
17. The cycloalkane-base dielectric liquid of claim 14 comprising
about 60 wt. % cycloalkanes or more.
18. The cycloalkane-base dielectric liquid of claim 16 comprising
about 66 wt. % cycloalkanes or more.
19. The cycloalkane base dielectric liquid of claim 16 wherein said
cycloalkane base oil boils at a temperature of from about
260.degree. C. to about 371.degree. C.
20. The cycloalkane-base dielectric liquid of claim 14 wherein a
majority of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
21. The cycloalkane-base dielectric liquid of claim 17 wherein a
majority of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
22. The cycloalkane-base dielectric liquid of claim 18 wherein a
majority of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
23. The cycloalkane-base dielectric liquid of claim 19 wherein a
majority of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
24. The cycloalkane-base dielectric liquid of claim 17 wherein 70
wt. % or more of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
25. The cycloalkane-base dielectric liquid of claim 18 wherein 70
wt. % or more of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
26. The cycloalkane-base dielectric liquid of claim 19 wherein 70
wt. % or more of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
27. The cycloalkane-base dielectric liquid of claim 19 wherein 80
wt. % or more of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
28. The cycloalkane-base dielectric liquid of claim 19 wherein 90
wt. % or more of the cycloalkanes comprise alkyl-substituted
cycloalkanes.
29. The cycloalkane-base dielectric liquid of claim 14 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +30 .mu.L/min. or less.
30. The cycloalkane-base dielectric liquid of claim 14 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +15 .mu.L/min. or less.
31. The cycloalkane-base dielectric liquid of claim 14 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +15 .mu.L/min. or less.
32. The cycloalkane-base dielectric liquid of claim 15 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +30 .mu.L/min. or less.
33. The cycloalkane-base dielectric liquid of claim 15 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +15 .mu.L/min. or less.
34. The cycloalkane-base dielectric liquid of claim 15 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +5 .mu.L/min. or less.
35. The cycloalkane-base dielectric liquid of claim 15 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to 0 .mu.L/min. or less.
36. The cycloalkane-base dielectric liquid of claim 25 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +15 .mu.L/min. or less.
37. The cycloalkane-base dielectric liquid of claim 25 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to +5 .mu.L/min. or less.
38. The cycloalkane-base dielectric liquid of claim 25 wherein the
anti-gassing agent(s) are effective to reduce the gassing tendency
of the dielectric liquid to 0 .mu.L/min. or less.
39. The cycloalkane-base dielectric liquid of claim 14 wherein the
antigassing agents are selected from the group consisting of
dihydrophenanthrene, phenyl ortho xylyl ethane, alkylated benzenes,
tetrahydro-5-(1-phenylethyl)-naphthalene, acenaphthene,
tetrahydro-naphthalene, alkylated tetrahydronaphthalenes,
tetrahydroquinoline.
40. The cycloalkane-base dielectric liquid of claim 14 wherein the
antigassing agents are selected from the group consisting of
alkyl-substituted aromatic compounds, alkyl substituted, partially
saturated aromatic compounds, and combinations thereof having from
9 to 11 carbon atoms; and, a combination comprising 80 wt. %
1,5-dimethyl naphthalene and 20 wt. % isomeric dimethyl
naphthalenes.
41. The cycloalkane-base dielectric liquid of claim 14 wherein the
quantity of anti-gassing agent is about 5 wt. % or less, based on
the weight of the dielectric liquid.
42. The cycloalkane-base dielectric liquid of claim 40 wherein the
quantity of anti-gassing agent is about 2 wt. % or less, based on
the weight of the dielectric liquid.
43. The cycloalkane-base dielectric liquid of claim 40 wherein the
quantity of anti-gassing agent is from about 0.5 wt. % to about 1
wt. %, based on the weight of the dielectric liquid.
44. The cycloalkane-base dielectric liquid of claim 15 wherein the
antigassing agents are selected from the group consisting of
dihydrophenanthrene, phenyl ortho xylyl ethane, alkylated benzenes,
tetrahydro-5-(1-phenylethyl)-naphthalene, acenaphthene,
tetrahydro-naphthalene, alkylated tetrahydronaphthalenes,
tetrahydroquinoline.
45. The cycloalkane-base dielectric liquid of claim 15 wherein the
antigassing agents are selected from the group consisting of
alkyl-substituted aromatic compounds, alkyl substituted, partially
saturated aromatic compounds, and combinations thereof having from
9 to 11 carbon atoms; and, a combination of 80 wt. % 1,5-dimethyl
naphthalene and 20 wt. % isomeric dimethyl naphthalenes.
46. The cycloalkane-base dielectric liquid of claim 15 wherein the
quantity of anti-gassing agent is about 5 wt. % or less, based on
the weight of the dielectric liquid.
47. The cycloalkane-base dielectric liquid of claim 15 wherein the
quantity of anti-gassing agent is about 2 wt. % or less, based on
the weight of the dielectric liquid.
48. The cycloalkane-base dielectric liquid of claim 15 wherein the
quantity of anti-gassing agent is from about 0.5 wt. % to about 1
wt. %, based on the weight of the dielectric liquid.
49. The cycloalkane-base dielectric liquid of claim 21 wherein the
antigassing agents are selected from the group consisting of
alkyl-substituted aromatic compounds, alkyl substituted, partially
saturated aromatic compounds, and combinations thereof having from
9 to 11 carbon atoms; and, a combination of 80 wt. % 1,5-dimethyl
naphthalene and 20 wt. % isomeric dimethyl naphthalenes.
50. The cycloalkane-base dielectric liquid of claim 21 wherein the
quantity of anti-gassing agent is about 2 wt. % or less, based on
the weight of the dielectric liquid.
51. The cycloalkane-base dielectric liquid of claim 22 wherein the
quantity of anti-gassing agent is from about 0.5 wt. % to about 1
wt. %, based on the weight of the dielectric liquid.
52. The cycloalkane-base dielectric liquid of claim 15 wherein the
amount of antioxidant is from about 0.07 wt. % to about 0.30 wt. %
based on the weight of the dielectric liquid.
53. The cycloalkane-base dielectric liquid of claim 51 wherein the
amount of antioxidant is from about 0.07 wt. % to about 0.30 wt. %
based on the weight of the dielectric liquid.
54. The cycloalkane-base dielectric liquid of claim 15 wherein the
amount of antioxidant is from about 0.01 wt. % to about 1.0 wt. %
based on the weight of the dielectric liquid.
55. The cycloalkane-base dielectric liquid of claim 51 wherein the
amount of antioxidant is from about 0.01 wt. % to about 1.0 wt. %
based on the weight of the dielectric liquid.
56. The cycloalkane-base dielectric liquid of claim 15 wherein said
amount of antioxidant is effective to produce a % sludge by mass at
72 hours of 0.15 or less and a 72 hour TAN of 0.5 or less, and to
produce a % sludge by mass at 164 hours of 0.5 or less and a 164
hour TAN of 0.6 or less.
57. The cycloalkane-base dielectric liquid of claim 34 wherein said
amount of antioxidant is effective to produce a % sludge by mass at
72 hours of 0.15 or less and a 72 hour TAN of 0.5 or less, and to
produce a % sludge by mass at 164 hours of 0.5 or less and a 164
hour TAN of 0.6 or less.
58. The cycloalkane-base dielectric liquid of claim 35 wherein said
amount of antioxidant is effective to produce a % sludge by mass at
72 hours of 0.15 or less and a 72 hour TAN of 0.5 or less, and to
produce a % sludge by mass at 164 hours of 0.5 or less and a 164
hour TAN of 0.6 or less.
59. The cycloalkane-base dielectric liquid of claim 14 comprising a
pour point of about -40.degree. C. or less, as measured using ASTM
D92.
60. The cycloalkane-base dielectric liquid of claim 15 comprising a
pour point of about -40.degree. C. or less, as measured using ASTM
D92.
61. The cycloalkane-base dielectric liquid of claim 58 comprising a
pour point of about -40 .sup.2C or less, as measured using ASTM
D92.
62. The cycloalkane-base dielectric liquid of claim 61 comprising:
a color of about 0.5 or less, as measured using ASTM D1500; a flash
point of about 145.degree. C. or greater, as measured using ASTM
D92; an interfacial tension of about 40 dynes/cm or more at
25.degree. C., as measured using ASTM D971; a relative density of
0.91 or less, according to ASTM D 1298; a visual examination of
clear and bright, according to ASTM D1524; a viscosity, as measured
by ASTM D445, of about 76 cSt or less at 0.degree. C., about 12.0
cSt or less at 40.degree. C., and from about 3.0 cSt or less at
100.degree. C.; about 35 ppm or less water according to ASTM D1533;
a content of less than 1 ppm polychlorinated biphenyl (PCB), as
measured using ASTM D4059; a dielectric breakdown voltage of 30 kV
or more at 60 Hz by disc electrodes, according to ASTM D877; a
dielectric breakdown voltage of 20 kV or more at 60 Hz and a 1.02
mm (0.040-inch ) gap using new oil by ASTM D1816; a dielectric
breakdown voltage impulse of about 145 kV or more at 25.degree. C.
using a needle-to-sphere grounded 25.4 mm (1-inch) gap, according
to ASTM D3300; a power factor at 60 Hz of 0.05% or less at
25.degree. C., and of 0.30% or less at 100.degree. C., according to
ASTM D924.
63. A method for making a cycloalkane base oil comprising: refining
crude under refining conditions effective to produce aromatic
vacuum gas oil boiling at a temperature in the range of from
371.degree. C. to 538.degree. C., the aromatic vacuum gas oil
comprising carbonaceous materials, a majority of the carbonaceous
materials being selected from the group consisting of cycloalkanes
and aromatics; contacting the aromatic vacuum gas oil with
hydrocracking catalyst under hydrocracking conditions effective to
produce hydrocracking product; subjecting hydrocracking product to
stripping conditions effective to increase the content of cyclic
hydrocarbons selected from the group consisting of cycloalkanes,
cycloalkenes, and combinations thereof and removing hydrogen
sulfide and ammonia and producing stripped hydrocracking product;
contacting stripped hydrocracking product with
isomerization/dewaxing/hydrogenation (IDH) catalyst comprising a
metal selected from the group consisting of platinum, palladium,
and combinations thereof, under IDH conditions effective to
saturate aromatics to cycloalkanes, reduce normal paraffins, and to
produce IDH product comprising greater than 50 wt. % of one or more
cyclic hydrocarbons selected from the group consisting of
cycloalkanes and cycloalkenes; without solvent extracting,
contacting IDH product with hydrotreating catalyst under
hydrotreating conditions effective to produce hydrotreated product
comprising greater than 50 wt. % cycloalkanes; and, separating from
said hydrotreated product cycloalkane base oil comprising a
quantity of less than 50 wt. % isoparaffins and 50 wt. % or more
cycloalkanes, said cycloalkane base oil boiling. at a temperature
in the range of from about 260.degree. C. to about 371.degree.
C.
64. The method of claim 63 wherein said cycloalkane base oil
comprises from 50 wt. % to 70 wt. % cycloalkanes having the formula
C.sub.nH.sub.2n wherein n is from 15 to 30.
65. The method of claim 63 wherein the IDH conditions comprise: IDH
temperatures of from about 250.degree. C. to about 390.degree. C.;
IDH gas pressures greater than atmospheric; IDH hydrogen
circulation rates of from about 400 to about 15,000 SCF/B; and, IDH
liquid hourly space velocities of from about 0.1 hr.-.sup.1 to
about 20 hr.sup.-1.
66. The method of claim 63 wherein the refining conditions are
effective to produce aromatic vacuum gas oil comprising the
following distribution of carbonaceous materials, in descending
order of concentration: aromatics>cycloalkanes
>isoparaffins>normal paraffins.
67. The method of claim 63 wherein the refining conditions are
effective to produce aromatic vacuum gas oil comprising from about
40 wt. % to about 60 wt. % aromatic content.
68. The method of claim 65 wherein the refining conditions are
effective to produce aromatic vacuum gas oil comprising from about
40 wt. % to about 60 wt. % aromatic content.
69. The method of claim 63 wherein the refining conditions are
effective to produce aromatic vacuum gas oil comprising from about
50 to about 60 wt. % aromatic content.
70. The method of claim 63 wherein the refining conditions are
effective to produce aromatic vacuum gas oil comprising from about
55 wt. % to about 60 wt. % aromatic content.
71. The method of claim 67 wherein the refining conditions are
effective to produce aromatic vacuum gas oil comprising: from about
20 wt. % to about 30 wt. % cycloalkanes; from about 10 wt. % to
about 15 wt. % isoparaffins; and, from about 5 wt. % to about 15
wt. % normal paraffins.
72. The method of claim 68 wherein the hydrocracking conditions
comprise a hydrocracking pressure greater than atmospheric pressure
and the stripping conditions comprise a stripping pressure greater
than atmospheric pressure.
73. The method of claim 72 wherein the IDH conditions comprise an
IDH pressure of greater than atmospheric.
74. The method of claim 73 wherein the IDH pressure is
substantially the same as the stripping pressure.
75. The method of claim 74 wherein the hydrocracking pressure is
about 30 atm or more.
76. The method of claim 68 wherein the hydrotreating conditions
comprise hydrotreating catalyst effective to convert unsaturated
bonds into saturated bonds comprising converting at least some of
any remaining aromatics into cycloalkanes; and, hydrotreating
pressure of greater than atmospheric pressure.
77. The method of claim 76 wherein the hydrotreating conditions
comprise a hydrotreating pressure substantially the same as the IDH
pressure.
78. The method of claim 77 wherein the hydrotreating pressure is
about 30 atm or more.
79. The method of claim 63 wherein the cycloalkane base oil
comprises from about 20 wt. % to about 40 wt. % isoparaffins.
80. The method of claim 64 wherein the cycloalkane base oil
comprises from about 20 wt. % to about 40 wt. % isoparaffins.
81. The method of claim 63 wherein a majority of the one or more
cycloalkanes in the cycloalkane base oil comprise alkyl-substituted
cycloalkanes having from about 15 to about 30 carbon atoms.
82. The method of claim 78 wherein a majority of the one or more
cycloalkanes in the cycloalkane base oil comprise alkyl-substituted
cycloalkanes having from about 15 to about 30 carbon atoms.
83. The method of claim 82 wherein 70 wt. % or more of the one or
more cycloalkanes in the cycloalkane base oil comprise said
alkyl-substituted cycloalkanes.
84. The method of claim 82 wherein 90 wt. % or more of the one or
more cycloalkanes in the cycloalkane base oil comprise said
alkyl-substituted cycloalkanes.
85. The method of claim 63 wherein the separation conditions are
fractionation conditions effective to separate hydrotreated product
boiling at a temperature of greater than 371.degree. C. as bottoms,
and effective to separate hydrotreated product boiling at a
temperature of less than 260.degree. C. as overhead.
86. The method of claim 84 wherein the separation conditions are
fractionation conditions effective to separate hydrotreated product
boiling at a temperature of greater than 371.degree. C. as bottoms,
and effective to separate hydrotreated product boiling at a
temperature of less than 260.degree. C. as overhead.
87. The method of claim 63 further comprising adding to said
cycloalkane base oil an amount of antigassing agent effective to
reduce gassing tendency of the hydrotreated product.
88. The method of claim 87 wherein the amount of antigassing agent
is effective to reduce gassing tendency to about +30 .mu.L/min. or
less.
89. The method of claim 87 wherein the amount of antigassing agent
is effective to reduce gassing tendency to about +15 .mu.gL/min. or
less.
90. The method of claim 87 wherein the amount of antigassing agent
is effective to reduce gassing tendency to about +5 .mu.gL/min. or
less.
91. The method of claim 87 wherein the amount of antigassing agent
is effective to reduce gassing tendency to about 0 .mu.gL/min. or
less.
92. The method of claim 86 further comprising adding to said
cycloalkane base oil an amount of antigassing agent effective to
reduce gassing tendency to about +5 .mu.gL/min. or less.
93. The method of claim 86 further comprising adding to said
cycloalkane base oil an amount of antigassing agent effective to
reduce gassing tendency to about 0 .mu.gL/min. or less.
94. The method of claim 63 further comprising adding to said
cycloalkane base oil about 5 wt. % or less antigassing agent to
produce cycloalkane-base dielectric liquid.
95. The method of claim 63 further comprising adding to said
cycloalkane base oil about 2 wt. % or less antigassing agent to
produce cycloalkane-base dielectric liquid.
96. The method of claim 63 further comprising adding to said
cycloalkane base oil about 0.5 wt. % to about 1 wt. % antigassing
agent to produce cycloalkane-base dielectric liquid.
97. The method of claim 92 further comprising adding to said
cycloalkane base oil about 2 wt. % or less antigassing agent to
produce cycloalkane-base dielectric liquid.
98. The method of claim 92 further comprising adding to said
cycloalkane base oil about 0.5 wt. % to about 1 wt. % antigassing
agent to produce cycloalkane-base dielectric liquid, said wt. %
being based on the weight of dielectric liquid.
99. The method of claim 63 further comprising adding to said
cycloalkane base oil a quantity of one or more antioxidant selected
from the group consisting of hindered phenols, cinnamate type
phenolic esters, and alkylated diphenylamines, said quantity being
effective to reduce sludge formation and total acid number in mg of
KOH/g (TAN) under oxidation conditions.
100. The method of claim 97 further comprising adding to said
cycloalkane base oil a quantity of one or more antioxidant selected
from the group consisting of hindered phenols, cinnamate type
phenolic esters, and alkylated diphenylamines, said quantity being
effective to reduce sludge formation and total acid number in mg of
KOH/g (TAN) under oxidation conditions.
101. The method of claim 99 wherein said one or more antioxidant is
selected from the group consisting of 2,6-ditertiary-butyl
para-cresol, 2,6-ditertiary butylphenol, and combinations
thereof.
102. The method of claim 100 wherein said one or more antioxidant
is selected from the group consisting of 2,6-ditertiary-butyl
para-cresol, 2,6-ditertiary butylphenol, and combinations
thereof.
103. The method of claim 101 further comprising adding to the
cycloalkane-base dielectric liquida second quantity of one or more
pour point depressants effective to reduce the pour point of the
cycloalkane-base dielectric liquid to about -30.degree. C. or
less.
104. The method of claim 102 further comprising adding to the
cycloalkane base oil a second quantity of one or more pour point
depressants effective to reduce the pour point of the
cycloalkane-base dielectric liquid to about -30.degree. C. or
less.
105. The method of claim 102 wherein said pour point depressant is
effective to reduce the pour point of the cycloalkane-base
dielectric liquid to about -40.degree. C. or less.
106. A method for making a cycloalkane base dielectric liquid
comprising: providing cycloalkane base oil comprising a quantity of
isoparaffins and from 50 wt. % to 70 wt. % cycloalkanes having the
formula C.sub.nH.sub.2n wherein n is from 15 to 30, said quantity
of isoparaffins being less than 50 wt. % of said cycloalkane base
oil; and, adding to said cycloalkane base oil one or more agent
selected from the group consisting of an amount of antigassing
agent effective to reduce gassing tendency of the cycloalkane base
oil and a quantity of one or more antioxidant selected from the
group consisting of hindered phenols, cinnamate type phenolic
esters, and alkylated diphenylamines, said quantity of one or more
antioxidant being effective to reduce sludge formation and total
acid number in mg of KOH/g (TAN) under oxidation conditions.
107. The method of claim 106 comprising adding to the cycloalkane
base oil an amount of antigassing agent, the amount being effective
to reduce gassing tendency to about +30 .mu.L/min. or less.
108. The method of claim 106 comprising adding to the cycloalkane
base oil an amount of antigassing agent, the amount being effective
to reduce gassing tendency to about +15 .mu.L/min. or less.
109. The method of claim 106 comprising adding to the cycloalkane
base oil an amount of antigassing agent, the amount being effective
to reduce gassing tendency to about +5 .mu.L/min. or less.
110. The method of claim 106 comprising adding to the cycloalkane
base oil an amount of antigassing agent, the amount being effective
to reduce gassing tendency to about 0 .mu.L/min. or less.
111. The method of claim 106 comprising adding to the cycloalkane
base oil an amount of antigassing agent, the amount being about 2
wt. % or less based on the weight of the cycloalkane base oil.
112. The method of claim 109 comprising adding to said cycloalkane
base oil an amount of antigassing agent, the amount being from
about 0.5 wt. % to about 1 wt. % based on the weight of the
cycloalkane base oil.
113. The method of claim 106 comprising adding to said cycloalkane
base oil a quantity of antioxidant, said one or more antioxidant
being selected from the group consisting of 2,6-ditertiary-butyl
para-cresol, 2,6-ditertiary butylphenol, and combinations
thereof.
114. The method of claim 112 comprising adding to said cycloalkane
base oil a quantity of antioxidant, said one or more antioxidant
being selected from the group consisting of 2,6-ditertiary-butyl
para-cresol, 2,6-ditertiary butylphenol, and combinations
thereof.
115. The method of claim 114 further comprising adding to the
cycloalkane-base dielectric liquid a second quantity of one or more
pour point depressants effective to reduce the pour point of the
cycloalkane-base dielectric liquid to about -30.degree. C. or
less.
116. The method of claim 106 wherein the cycloalkane base oil boils
at a temperature in the range of from about 260.degree. C. to about
371.degree. C.
117. The method of claim 114 wherein the cycloalkane base oil boils
at a temperature in the range of from about 260.degree. C. to about
371.degree. C. .
Description
FIELD OF THE APPLICATION
[0001] The application relates to "cycloalkane" base oil(s), to
cycloalkane-base dielectric liquid(s) made using the cycloalkane
base oil(s), to methods of making the cycloalkane base oil(s) and
to the cycoalkane-base dielectric liquid(s).
BACKGROUND
[0002] Dielectric liquids typically are manufactured from a gas oil
fraction derived at atmospheric pressure from naphthenic crudes.
Dielectric liquids manufactured using other feedstocks are
desirable.
BRIEF SUMMARY
[0003] The present application provides cycloalkane base oil
comprising a quantity of isoparaffins and from 50 wt. % to 70 wt. %
cycloalkanes having the formula C.sub.nH.sub.2n wherein n is from
15 to 30, said quantity of isoparaffins being less than 50 wt. % of
said cycloalkane base oil.
[0004] The application also provides a cycloalkane-base dielectric
liquid comprising:
[0005] cycloalkane base oil comprising a quantity of isoparaffins
and from 50 wt. % to 70 wt. % cycloalkanes having the formula
C.sub.nH.sub.2n wherein n is from 15 to 30, said quantity of
isoparaffins being less than 50 wt. % of said cycloalkane base oil;
and,
[0006] one or more non-phenolic alkyl substituted or partially
saturated aromatic anti-gassing agent comprising at least one
labile hydrogen atom, said quantity being effective to reduce the
gassing tendency of the dielectric liquid.
[0007] The application provides a method for making a cycloalkane
base oil comprising:
[0008] refining crude under refining conditions effective to
produce aromatic vacuum gas oil boiling at a temperature in the
range of from about 371.degree. C. to about 538.degree. C., the
aromatic vacuum gas oil comprising carbonaceous materials, a
majority of the carbonaceous materials being selected from the
group consisting of cycloalkanes and aromatics;
[0009] contacting the aromatic vacuum gas oil with hydrocracking
catalyst under hydrocracking conditions effective to produce
hydrocracking product;
[0010] subjecting hydrocracking product to stripping conditions
effective to increase the content of cyclic hydrocarbons selected
from the group consisting of cycloalkanes, cycloalkenes, and
combinations thereof and removing hydrogen sulfide and ammonia and
producing stripped hydrocracking product;
[0011] contacting stripped hydrocracking product with
isomerization/dewaxing/hydrogenation (IDH) catalyst comprising a
metal selected from the group consisting of platinum, palladium,
and combinations thereof, under IDH conditions effective to
saturate aromatics to cycloalkanes, reduce normal paraffins, and to
produce IDH product comprising greater than 50 wt. % of one or more
cyclic hydrocarbons selected from the group consisting of
cycloalkanes and cycloalkenes;
[0012] without solvent extracting, contacting IDH product with
hydrotreating catalyst under hydrotreating conditions effective to
produce hydrotreated product comprising greater than 50 wt. %
cycloalkanes; and,
[0013] separating from said hydrotreated product cycloalkane base
oil comprising less than 50 wt. % isoparaffins and 50 wt. % or more
cycloalkanes, said cycloalkane base oil boiling at a temperature in
the range of from about 260.degree. C. to about 371.degree. C.
[0014] A method for making a cycloalkane base dielectric liquid
comprising:
[0015] providing cycloalkane base oil comprising a quantity of
isoparaffins and from 50 wt. % to 70 wt. % cycloalkanes having the
formula C.sub.n H.sub.2n wherein n is from 15 to 30, said quantity
of isoparaffins being less than 50 wt. % of said cycloalkane base
oil; and,
[0016] adding to said cycloalkane base oil one or more agent
selected from the group consisting of an amount of antigassing
agent effective to reduce gassing tendency of the cycloalkane base
oil and a quantity of one or more antioxidant selected from the
group consisting of hindered phenols, cinnamate type phenolic
esters, and alkylated diphenylamines, said quantity of one or more
antioxidant being effective to reduce sludge formation and total
acid number in mg of KOH/g (TAN) under oxidation conditions.
DETAILED DESCRIPTION
[0017] The present application provides cycloalkane base oil(s) for
producing cycloalkane-base dielectric liquid(s).
[0018] A "cycloalkane base oil" is produced from an aromatic base
oil feedstock, preferably an "aromatic vacuum gas oil" produced
from the refining of crude oil. Substantially any crude oil may be
used as the source of the aromatic vacuum gas oil. Suitable crudes
include, but are not necessarily limited to: Arabian Light, Arabian
Medium, Arab Heavy, Orienta, Kuwati, Isthmus, Maya, Oman, Brent,
and combinations thereof.
[0019] A majority of the carbonaceous materials in suitable
"aromatic vacuum gas oils" are selected from the group consisting
of cycloalkanes and aromatics. Aromatic vacuum gas oil generally
comprises the following distribution of carbonaceous materials, in
descending order of concentration:
aromatics>cycloalkanes>isoparaffins>normal paraffins.
[0020] Suitable aromatic vacuum gas oils boil at a temperature in
the range of from about 260.degree. C. (500.degree. F.) to about
538.degree. C. (1000.degree. F.), preferably from about 371.degree.
C. (700.degree. F.) to about 538.degree. C. (1000.degree. F.). The
aromatic content of suitable aromatic vacuum gas oils is from about
40 wt. % to about 60 wt. %. In preferred embodiments, the aromatic
content of the aromatic vacuum gas oils is from about 50 to about
60 wt. %, more preferably from about 55 wt. % to about 60 wt. %.
Aromatic vacuum gas oils also typically comprise from about 20 wt.
% to about 30 wt. % cycloalkanes, from about 10 wt. % to about 15
wt. % isoparaffins, from about 5 wt. % to about 15 wt. % normal
paraffins.
[0021] The aromatic vacuum gas oils also may be mixed with other
base oil feedstocks, including, but not necessarily limited to
solvent extracted raffinates, soft wax, slack wax, lube boiling
range product from a Fischer-Tropsch conversion of gas-to-liquids,
and combinations thereof.
[0022] In order to produce cycloalkane base oil, aromatic vacuum
gas oil is subjected to hydroprocessing conditions. In a preferred
embodiment, the hydroprocessing conditions comprise: contacting the
aromatic vacuum gas oil with hydrocracking catalyst under
hydrocracking conditions effective to produce hydrocracking
product; subjecting the hydrocracking product to stripping
conditions effective to remove hydrogen sulfide and any ammonia and
to produce stripped hydrocracking product; contacting the stripped
hydrocracking product with isomerization/dewaxing/hydrogenation
("IDH" ) catalyst under conditions effective to saturate aromatics
to produce cycloalkanes and to reduce normal paraffins to produce
an IDH product comprising carbonaceous molecules, a majority of the
carbonaceous molecules comprising one or more cyclic hydrocarbons
selected from the group consisting of cycloalkanes and
cycloalkenes; contacting IDH product with hydrotreating catalyst
under hydrotreating conditions effective to produce hydrotreated
product comprising greater than 50 wt. % cycloalkanes; and
subjecting the hydrotreated product to separation conditions
effective to separate a cycloalkane base oil comprising a fraction
having a boil at a temperature in the range of from about
260.degree. C. to about 371.degree. C.
Hydrocracking Conditions
[0023] In order to produce the cycloalkane base oil, the aromatic
vacuum gas oil is subjected to hydrocracking conditions generally
comprising hydrocracking catalyst. Substantially any hydrocracking
catalyst effective to increase the rate of desired hydrocracking is
suitable. The hydrocracking catalyst generally comprises a suitable
hydrocracking metal on a carrier.
[0024] Suitable hydrocracking metals include, but are not
necessarily limited to sulfided catalysts comprising one or more
metals selected from the group consisting of cobalt, chromium,
molybdenum, tungsten, magnesium, rhenium, iron, ruthenium, iridium,
nickel, palladium, platinum, and combinations thereof. In one
embodiment, the hydrocracking metal is one or more metal selected
from the group consisting of Ni/W, Ni/Mo, and Co/Mo. In a more
preferred embodiment, the hydrocracking metal is one or more metal
selected from the group consisting of Ni/W and Co/Mo.
[0025] The hydrocracking catalyst comprises substantially any
carrier which provides sufficient surface area and does not
interfere with hydrocracking. Examples of suitable carriers
include, but are not necessarily limited to metal oxides and
molecular sieves. In one embodiment, the carrier is selected from
the group consisting of alumina and crystalline alumino
silicates.
[0026] Suitable hydrocracking conditions comprise: hydrocracking
temperatures of from about 200.degree. C. and about 450.degree. C.;
hydrocracking hydrogen gas pressures of greater than atmospheric,
preferably about 30 atmospheres or more; hydrocracking hydrogen
circulation rates of from about 400 SCF/B (standard cubic feet per
barrel) to about 15,000 SCF/B; and hydrocracking liquid hourly
space velocities of from about 0.1 hr-1 to about 20 hr-1.
Generally, the hydrocracking conditions are effective to convert
polynuclear aromatics in the heavy aromatic gas oil into smaller
partially hydrogenated aromatic and hydrogenated species, to
convert some normal paraffins to isoparaffins and to convert sulfur
and nitrogen present in the heavy aromatic gas oil to hydrogen
sulfide and ammonia.
[0027] Stripping Conditions The hydrocracking product is subjected
to stripping conditions effective to remove hydrogen sulfide and
ammonia and to produce a stripped hydrocracking product. Suitable
stripping conditions comprise a temperature of from about
200.degree. C. to about 300.degree. C. and an effective stripping
pressure, preferably greater than atmospheric pressure. In a more
preferred embodiment, the stripping pressure is substantially the
same as the hydrocracking pressure, most preferably about 30 atm or
greater. Preferably, stripping gas is hydrogen essentially free of
hydrogen sulfide and ammonia. Isomerization/Dewaxing/Hydrogenation
(IDH) Conditions The stripped hydrocracking product is subjected to
hydroprocessing conditions, preferably
isomerization/dewaxing/hydrogenation ("IDH") conditions, effective
to increase the content of hydrogenated and partially hydrogenated
cyclic hydrocarbons selected from the group consisting of
cycloalkanes, cycloalkenes, and combinations thereof. The
hydroprocessing conditions, preferably IDH conditions, also
typically increase the content of isoparaffins by isomerizing
normal and near normal paraffins to isoparaffins. In a preferred
embodiment, the hydroprocessing conditions are effective to produce
about 20 wt. % or more isoparaffins, more preferably from about 20
wt. % to less than 50 wt. % isoparaffins, most preferably from
about 20 wt. % to about 40 wt. % isoparaffins.
[0028] The IDH conditions generally comprise contacting the
stripped hydrocracking product with one or more IDH catalyst at an
IDH temperature, an IDH pressure, and an IDH hydrogen flowrate
effective to increase the content of cyclic hydrocarbons selected
from the group consisting of cycloalkanes, cycloalkenes, and
combinations thereof. The IDH conditions also generally are
effective to increase the content of isoparaffins.
[0029] Suitable IDH catalysts comprise one or more IDH metal,
including but not necessarily limited to cobalt, chromium,
molybdenum, tungsten, magnesium, rhenium, iron, ruthenium, iridium,
nickel, palladium, platinum, and combinations thereof. Preferred
IDH metal(s) include, but are not necessarily limited to platinum,
palladium, and combinations thereof.
[0030] The IDH metal generally is disposed on a suitable IDH metal
carrier. Suitable IDH metal carriers include, but are not
necessarily limited to molecular sieves and metal oxides. Suitable
molecular sieves include, but are not necessarily limited to
zeolites and silicoaluminophosphate molecular sieves. Suitable
metal oxides include, but are not necessarily limited to alumina. A
preferred IDH metal carrier comprises silicoaluminophosphate
molecular sieves.
[0031] Suitable zeolites are intermediate pore size zeolites.
Preferred intermediate pore size zeolites have a pore diameter of
from about 0.35 to about 0.8 nm. Specific examples of suitable
zeolites include, but are not necessarily limited to zeolite Y,
zeolite beta, zeolite theta, mordenite, ZSM-3, ZSM-4, ZSM-5,
ZSM-11, ZSM-12, ZSM-18 18, ZSM-20, ZSM-22, ZSM-23, ZSM-35, ZSM-38,
ZSM-48, SSZ-32, offretite, ferrierite, zeolite alpha, and mixtures
thereof. Because of their isomerization selectivities, preferred
zeolites include, but are not necessarily limited to ZSM-12,
ZSM-23, ZSM-22, SSZ-32, and combinations thereof.
[0032] Suitable silicoaluminophosphate molecular sieves include,
but are not necessarily limited to SAPO-11, SAPO-31, SAPO-41, and
combinations thereof. A preferred silicoaluminophosphate molecular
sieve is SAPO-11. See also the following U.S. patents, which are
hereby incorporated by reference: U.S. Pat. Nos. 6,090,989;
4,500,417; 4,906,350; 4,943,672; 5,059,299; 5,135,63; 5,282,958,
5,306,860, 5,362,378; and European Patent No. 0 776 959 A2.
[0033] Suitable IDH conditions comprise: IDH temperatures of from
about 250.degree. C. to about 390.degree. C.; IDH gas pressures
greater than atmospheric, preferably substantially the same as the
hydrocracking pressure, which is preferably about 30 atm or more;
IDH hydrogen circulation rates of from about 400 to about 15,000
SCF/B; and, IDH liquid hourly space velocities of from about 0.1
hr..sup.-1 to about 20 .sup.-1 .
Hydrotreating
[0034] In a preferred embodiment, the hydroprocessing product is
hydrotreated. Hydrotreating comprises contacting the IDH product
with hydrotreating catalyst under hydrotreating conditions
effective to convert unsaturated bonds and remaining aromatics, in
particular multi-ring aromatics, in the IDH product into saturated
bonds and cycloalkanes, respectively.
[0035] Suitable hydrotreating conditions comprise: hydrotreating
temperatures of from about 190.degree. C. to about 340.degree. C.;
hydrotreating pressures greater than atmospheric, preferably
substantially the same as the hydrocracking and IDH pressure, which
preferably is about 30 atm or more; hydrogen circulation rates of
from about 400 to about 15,000 SCF/B.
[0036] Suitable hydrotreating catalyst comprises hydrotreating
metal effective to increase the rate of hydrogenation of
unsaturated bonds and aromatics in the IDH product. Suitable
hydrotreating metal(s) include but are not necessarily limited to
cobalt, chromium, molybdenum, tungsten, magnesium, rhenium, iron,
ruthenium, iridium, nickel, palladium, platinum, and combinations
thereof. Preferred hydrotreating metals are selected from the group
consisting of Ni, Pt, Pd, and combinations thereof.
[0037] The hydrotreating metal generally is on a suitable support
which has sufficient surface area and does not interfere with the
hydrotreating process. Suitable hydrotreating catalyst supports
include, but are not necessarily limited to metal oxides and
molecular sieves. Preferred hydrotreating catalyst supports
comprise dispersed zeolite effective to increase saturation of
remaining aromatic molecules.
Recovery of Cycloalkane Base Oil
[0038] The resulting hydrotreated product boils at a temperature in
the range of from about 38.degree. C. (100.degree. F.) to about
538.degree. C. (1000.degree. F.). The hydrotreated product is
subjected to separation conditions effective to separate
cycloalkane base oil, preferably cycloalkane base oil boiling at a
temperature in the range of from about 260.degree. C. to about
371.degree. C. Any suitable separation conditions may be used as
long as they are effective to separate cycloalkane base oil boiling
at a temperature in the range of from about 260.degree. C. to about
371.degree. C. from the portion of the hydrotreated product (a)
boiling at a temperature greater than 700.degree. F. (371.degree.
C.), and (b) boiling at a temperature less than 500.degree. F.
(260.degree. C.).
[0039] In a preferred embodiment, the hydrotreated product is
subjected to fractionation conditions comprising removing
hydrotreated product boiling at a temperature of greater than
371.degree. C. (700.degree. F.) as a bottoms, and removing
hydrotreated product boiling at a temperature of less than
260.degree. C. (500.degree. F.) as an overhead.
[0040] A majority of carbonaceous molecules in the cycloalkane base
oil comprise cycloalkanes, preferably alkyl-substituted
cycloalkanes. Preferably 50 wt. % or more, more preferably 60 wt. %
or more, even more preferably 66 wt. % or more of the carbonaceous
molecules in the cycloalkane base oil comprise cycloalkanes.
[0041] Cycloalkanes generally have the formula C.sub.n H.sub.2n
where n is the total number of carbon atoms. In a preferred
embodiment, the base oil comprises cycloalkanes wherein n is from
about 15 to about 30.
[0042] In a more preferred embodiment, a majority of the
cycloalkanes comprise alkyl-substituted cycloalkanes. Preferably,
about 70 wt. % or more, more preferably about 80 wt. % or more,
even more preferably about 90 wt. % or more, and most preferably
about 99 wt. % or more of the cycloalkanes comprise
alkyl-substituted cycloalkanes.
[0043] The cycloalkane base oil comprises less than 50 wt. %
isoparaffins, preferably from about 20 wt. % to less than 50 wt. %
isoparaffins, more preferably from about 20 wt. % to about 40 wt. %
isoparaffins. The cycloalkane base oil also preferably comprises
about 15 ppm sulfur or less.
Production of Cycloalkane-Base Dielectric Liquid(s)
[0044] The cycloalkane base oil of the present application has a
variety of uses, including but not necessarily limited to use as a
base oil in cycloalkane-base dielectric liquids. In a preferred
embodiment, the cycloalkane base oil is used to produce
cycloalkane-base dielectric liquids meeting the requirements of
ASTM D 3487 ("Standard Specification for Mineral Insulating Oil
Used in Electrical Apparatus," incorporated herein by reference).
Most preferably the cycloalkane base oil is used to produce
dielectric liquids suitable for use as transformer oil.
[0045] Many types of conventional electrical equipment contain a
dielectric fluid for dissipating the heat generated by energized
components, and for insulating those components from the equipment
enclosure and from other internal parts and devices. Examples of
such equipment include, but are not necessarily limited to
transformers, capacitors, switches, regulators, circuit breakers,
cables, reclosers, and x-ray equipment.
[0046] A transformer transfers electric power from one circuit to
another electromagnetically. Transformers are used in the
transmission of electrical power.
[0047] Larger transformers generally require insulation of coils
and/or conductors in order to protect the transformer at normal
operating voltages, during temperature overvoltages, and also
during transient overvoltages, which may result from lightning
strikes or switching operations. When insulation fails, an internal
fault or short circuit may occur. Such occurrences could cause the
equipment to fail, typically leading to system outages and possibly
endangering persons in the vicinity of the equipment.
[0048] In order to effectively transfer heat away from a
transformer core and coil assembly and to maintain an acceptable
operating temperature, conventional transformers use relatively
large volumes of dielectric fluid as insulation.
[0049] In the past, dielectric liquids made from paraffinic oils
tended to have inherently poor low temperature viscometric
properties and generally did not exhibit low gassing performance,
as required by ASTM D 3487.
[0050] The gassing tendency of the cycloalkane-base dielectric
liquid is a measure of the rate of absorption or desorption of
hydrogen into or out of the dielectric liquid under prescribed
laboratory conditions. Low gassing performance is important
because, if hydrogen is evolved due to electrical stress, a liquid
having low gassing tendency tends to absorb the evolved hydrogen
and thereby reduce the chances of an explosion.
[0051] The cycloalkane-base dielectric liquids of the present
application exhibit both low temperature viscometric properties and
low gassing tendency.
[0052] Gassing tendency is reduced by adding one or more
anti-gassing gassing agent(s). Preferably, the anti-gassing
agent(s) reduce the gassing tendency of the dielectric liquid to
+30 .mu.L/min. or less, preferably 15 .mu.L/min. or less, more
preferably 5 .mu.L/min. or less, preferably 0 .mu.L/min. or less,
according to ASTM Test Method D2300.
[0053] The antigassing agent(s) generally are antigassing
aromatic(s) other than phenolic compounds which comprise at least
one labile hydrogen atom. Examples of suitable antigassing agents
include, but are not necessarily limited to agents having from 9 to
11 carbon atoms selected from the group consisting of
alkyl-substituted aromatic compounds, alkyl substituted, partially
saturated aromatic compounds, and combinations thereof.
[0054] Examples of suitable anti-gassing agents include, but are
not necessarily limited to dihydrophenanthrene, phenyl ortho xylyl
ethane, alkylated benzenes, including diethylbenzenes,
tetrahydro-5-(1-phenylethyl)-naphthalene, acenaphthene,
tetrahydro-naphthalene, alkylated tetrahydronaphthalenes,
tetrahydroquinoline. In one embodiment, the aromatic oil comprises
about 80 wt. % 1,5-dimethyl naphthalene and about 20 wt. % isomeric
dimethyl naphthalenes. Preferably, the one or more anti-gassing
agent(s) are added to the cycloalkane-base oil in an amount of
about 5 wt. % or less, more preferably about 2 wt. % or less, even
more preferably from about 0.5 wt. % to about 1 wt. %, most
preferably about 1 wt. %, based on the volume of the base oil.
[0055] In a preferred embodiment, antioxidant (described above)
also is added the cycloalkane base oil to improve oxidation
stability of the cycloalkane-base dielectric liquid, thereby
minimizing the development of oil sludge and acidity during
storage, processing, and service. Minimizing oxidation minimizes
electrical conduction and metal corrosion, maximizes system life,
maximizes electrical breakdown strength, and ensures satisfactory
heat transfer.
[0056] Preferably, when subjected to the acid sludge test (ASTM
D2440), the cycloalkane-base dielectric liquid produces a % sludge
by mass at 72 hours of 0.15 or less and a 72 hour "total acid
number" or "TAN" of 0.5 or less (mg of KOH/g). The cycloalkane-base
dielectric liquid also preferably produces a % sludge by mass at
164 hours of 0.5 or less and a TAN of 0.6 or less.
[0057] Generally, antioxidant is added in order to minimize sludge
and TAN. In a preferred embodiment, the dielectric liquid comprises
from about 0.01 wt. % to about 1.0 wt. % antioxidant, preferably
from about 0.07 wt. % to about 0.30 wt. % antioxidant based on the
weight of the dielectric liquid.
[0058] Substantially any antioxidant accepted for use in the
particular type of dielectric fluid is suitable. Preferred
antioxidants for use in electrical oils are hindered phenols,
cinnamate type phenolic esters, and alkylated diphenylamines. More
preferred antioxidants, particularly for use in transformer oils,
are selected from the group consisting of 2,6-ditertiary-butyl
para-cresol, 2,6-ditertiary butylphenol, and combinations thereof.
A most preferred antioxidant is a combination of
2,6-ditertiary-butyl para-cresol and 2,6-ditertiary
butylphenol.
[0059] If desired, a quantity of one or more pour point depressants
may be added to the cycloalkane base oil to depress the pour point
of the product to about -30.degree. C. or less, preferably to about
-40.degree. C. or less. A variety of pour point depressants may be
used. Suitable pour depressants include, but are not necessarily
limited to pour point depressants based on polymethacrylate
chemicals. If pour point depressant(s) are added, the quantity of
pour point depressant typically is from about 0.01 wt % to about
0.2 wt % based on the weight of the cycloalkane base oil.
[0060] The cycloalkane-base dielectric liquids meet specifications
required for a variety of applications, including but not
necessarily limited to electrical oils. A preferred use for the
cycloalkane-base dielectric liquids is transformer oil(s).
[0061] In addition to oxidation resistance and low gassing
tendency, the cycloalkane-base dielectric liquids preferably have a
number of other properties, including but not necessarily limited
to electrical resistance and thermal stability. In a most preferred
embodiment, the cycloalkane-base dielectric liquids meet relevant
specifications for physical, electrical, and chemical properties
for electrical oils provided by ASTM D 3487. In a preferred
embodiment, the cycloalkane-base dielectric liquid also meets other
relevant standards, incorporated herein by reference, including,
but not necessarily limited to: National Electrical Manufacturers
Association(NEMA) TR-P8-1975; U.S. Government Military
Specification W-I-530A and Amendment 2 for Class I and Class II
fluids (Type I and Type II, respectively)-supercedes the Department
of the Navy specification OS-1023; NATO symbol S-756, British
Standard BS 148.
[0062] The ASTM physical property requirements for electrical oils
include, but are not necessarily limited to: a color of about 0.5
or less, as measured using Test Method D1500 (incorporated herein
by reference); a flash point of about 145.degree. C. or greater, as
measured using Test Method D92 (incorporated herein by reference)
(incorporated herein by reference); an interfacial tension of about
40 dynes/cm or more at 25.degree. C., as measured using Test Method
D971 (incorporated herein by reference); a pour point of about
-40.degree. C. or less, as measured using Test Method D92
(incorporated herein by reference); a relative density of 0.91 or
less, according to Test Method D 1298 (incorporated herein by
reference); a visual examination of clear and bright, according to
Test Method D1524 (incorporated herein by reference); and, a
viscosity of about 76 cSt or less at 0.degree. C., about 12.0 cSt
or less at 40.degree. C., and from about 3.0 cSt or less at
100.degree. C., as measured by Test Method D445 (incorporated
herein by reference).
[0063] The cycloalkane-base dielectric liquid also preferably meets
the electrical property requirements for electrical oils, including
but not necessarily limited to the ASTM requirements of: a
dielectric breakdown voltage of 30 kV or more at 60 Hz by disc
electrodes, according to Test Method D877 (incorporated herein by
reference); a dielectric breakdown voltage of 20 kV or more at 60
Hz and a 1.02 mm (0.040-inch) gap using new oil by D1816
(incorporated herein by reference); a dielectric breakdown voltage
impulse of about 145 kV or more at 25.degree. C. using a
needle-to-sphere grounded 25.4 mm (1-inch) gap, according to Test
Method D3300 (incorporated herein by reference), and, a power
factor at 60 Hz of 0.05% or less at 25.degree. C., and of 0.30% or
less at 100.degree. C., using Test Method D924 (incorporated herein
by reference).
[0064] The cycloalkane-base dielectric liquid also preferably meets
chemical property requirements for electrical oils, including but
not necessarily limited to the ASTM requirements of: an oxidation
inhibitor content for Type I oils of 0.08 wt. % or less, and for
Type II oils of 0.3 wt. % or less, as measured using Test Method
D2668 (incorporated herein by reference), or, where the oxidation
inhibitor is 2,6-ditertiary butyl cresol, as measured using Test
Method D1473 (incorporated herein by reference); a low content of
elemental sulfur and thermally unstable sulfur-bearing compounds to
prevent corrosion of certain metals such as copper and silver in
contact with the dielectric liquid, according to Test Method D1274
(incorporated herein by reference); 35 ppm or less water according
to Test Method D1533 (incorporated herein by reference); a
neutralization number of 0.03 mg KOH/g or less, using Test Method
D974 (incorporated herein by reference); and, a non-detectible
polychlorinated biphenyl (PCB) content, or a content of less than 1
ppm, as measured using Test Method D4059 (incorporated herein by
reference).
[0065] The application will be better understood with reference to
the following examples, which are illustrative only:
EXAMPLE 1
[0066] A cycloalkane base oil produced as described above was
analyzed and determined to have the following properties:
TABLE-US-00001 API 31.6 Specific Gravity g/cc 0.8676 Pour Point,
.degree. C. (.degree. F.) -42.8 (-45) Cloud Point, .degree. C.
(.degree. F.) -30.5 (-22.9) Viscosity @ 40.degree. C. mm.sup.2/s
(cSt)* 9.172 Viscosity @ 100.degree. C. mm.sup.2/s (cSt) 2.397
Viscosity Index 68.7 *The viscosity measurements were performed
using an automatic Cannon CAV4 instrument. Viscometer according to
ASTM D 445, incorporated herein by reference.
EXAMPLE 2
[0067] A cycloalkane base oil produced as described above was
analyzed and determined to have the following properties:
TABLE-US-00002 API 32.4 Specific Gravity g/cc 0.8633 Pour Point,
.degree. C. (.degree. F.) -47(-52.6) Cloud Point, .degree. C.
(.degree. F.) -38(-36.4) Cleveland Open Cup (COC) Flash Point,
.degree. C. (.degree. F.) 157.8(316) Viscosity @ 40.degree. C.
mm.sup.2/s (cSt) 7.471 Viscosity @ 100.degree. C. mm.sup.2/s (cSt)
2.112 Viscosity Index 70.7 UV Aromatics Monoaromatics (wt %) 0.97
Diaromatics (wt %) 1.06 tri + aromatics (wt %) 0.7 Total (wt %)
2.73
EXAMPLE 3
[0068] A cycloalkane base oil produced as described above was
analyzed. Simulated distillation by gas chromatography was
performed to determine the temperatures (.degree. C. ) at which 5
wt % and 95 wt % of the base oil vaporized. ASTM D 6352 "Standard
Test Method for Boiling Range Distribution of Petroleum Distillates
in Boiling Range from 174 to 700 Degrees C. by Gas Chromatography,"
incorporated herein by reference. The results are given in the
following Table, along with the physical properties of the base
oil: TABLE-US-00003 5% vaporization temperature, .degree. C.
(.degree. F.) 267.8(514) 95% vaporization temperature, .degree. C.
(.degree. F.) 400.6(753) Viscosity @ 40.degree. C. mm.sup.2/s (cSt)
9.9 Viscosity @ 100.degree. C. mm.sup.2/s (cSt) 2.5 VI 53 Density,
g/ml @ 15.6.degree. C. (60.degree. F.) 0.854 API Gravity 34.1 Pour
Point, .degree. C. (.degree. F.) -45(-49) Pensky-Martens Closed Cup
(PMCC) Flash, .degree. C. 148 UV Aromatics, mmol/100 g 6 Sulfur,
ppm 1 Nitrogen, ppm 1
EXAMPLE 4
[0069] Cycloalkane base oil from Example 3 was mixed with either
0.075 wt. % or 0.28 wt. % butylated hydroxytoluene (BHT), obtained
from CRI Fine Chemicals, Inc. Samples were prepared containing no
added aromatic oil, containing 2.0 wt % C9-C11 alkylbenzenes
("AB"), containing 0.5 wt. % C9-C11 alkylbenzenes, containing 0.5
wt. % dimethyl naphthalenes (DMN), and containing 1 wt. % added
DMN. The resulting mixture was oxidized at a bath temperature of
110.degree. C., in the presence of a copper catalyst coil, by
bubbling oxygen through duplicate test specimens for 72 and 164 h,
respectively. The cycloalkane base oil was evaluated at the end of
each aging period by measuring the amount of sludge and acid
formed. The test specimen was diluted with n-heptane and the
solution filtered to remove the sludge. The sludge was dried and
weighed. The sludge free solution was titrated at room temperature
with 0.01 N potassium hydroxide to the end point indicated by the
color change (green-brown) of the added p-naphtol-benzein solution.
ASTM D 2440, incorporated herein by reference. Test Method D2300
Procedure B, incorporated herein by reference, was performed using
a gassing cell assembly and buret assembly to determine the
resulting gassing tendency.
[0070] The samples were mixed with an acidified, aqueous solution
of methylene blue and treated with chloroform to extract
hydrophobic ion pairs. The combined chloroform extracts were washed
with an acid solution to remove the less hydrophobic ion pairs
(having low partition coefficients).
[0071] The intensity of the blue color remaining in the chloroform
extract was measured at a wavelength of maximum absorption near 650
nm. The results are given in the following Table: TABLE-US-00004 72
hr. 72 hr. 164 hr. 164 hr. Gassing sludge TAN Sludge TAN Tendency
D3487 0.15 max 0.5 max 0.3 max 0.6 30 max specification Cycloalkane
0.01 0.01 0.01 0.01 49 base oil Cycloalkane 0.01 0.01 0.03 0.13 45
base oil Cycloalkane <0.01 <0.1 0.01 <0.01 -56 base oil +
0.28 wt. % BHT + 2.0 wt. % AB Cycloalkane 0.01 0.11 0.03 0.3 -7
base oil + 0.075 wt. % BHT + 0.5 wt. % AB Cycloalkane 0.02 0.01
0.05 1.74 23 base oil + 0.075 wt. % BHT + 0.5 wt. % DMN Cycloalkane
0.01 0.01 0.01 0.01 -5 base oil + 0.075 wt. % BHT + 1 wt. % DMN
With 0.28 wt % BHT and 2.0 wt % AB, the sample performed well
exhibiting a negative gassing tendency. With 0.28 wt % BHT and 0.5
wt % AB, the sample performed well exhibiting a negative gassing
tendency. With 0.075 BHT, the samples containing 0.5 wt. % DMN and
1.0 wt. % DMN performed well. The sample containing 2.0 wt. % AB,
0.5 wt. % AB, and 1.0 wt. % DMN performed exceptionally well,
exhibiting a negative gassing tendency. The 164 hour TAN result is
believed to be due to experimental error.
[0072] Persons of ordinary skill in the art will recognize that
many modifications may be made to the foregoing without departing
from the spirit and scope thereof. The embodiment described herein
is meant to be illustrative only and should not be taken as
limiting the invention, which is defined in the following
claims.
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