Anhydrous Fire Resistant Hydraulic Fluids using Polyalkylene Glycols
ASTM D02 – Symposium on Fire Resistant Fluids June 24th, 2013
Authors
Andrew Larson, The Dow Chemical Company
Dr. Martin Greaves, The Dow Chemical Company
Contents
• Examine performance of non-phosphorus based anhydrous fire resistant hydraulic fluids
– Compare two conventional PAGs with a synthetic ester
• New class of PAG known as oil soluble polyalkylene glycols (OSPs)
– Examine fire resistance behavior of the formulated fluid containing an OSP and compare to other PAGs
Classification of Fire Resistant Fluids
Classification Description
HFAE HFAS
Oil-in-water emulsions containing >95% water (v/v) and up to 5% of additives
Chemical solutions in water containing >75% water (v/v) and an additive package and water soluble polymer thickener
HFB Water-in-oil emulsions that typically contain >40% water (v/v) and an additive package
HFC Water polymer solutions containing >35% water (v/v), a high molecular weight polyalkylene glycol thickener and an additive package
HFC-E (a) HFC fluids with a lower water content of about 20% water (v/v)
HFDR Anhydrous synthetic phosphate esters containing an additive package HFDU Anhydrous synthetics (other than phosphate esters). For
example polyol esters, vegetable oils and polyalkylene glycols. The base oil represents about 95% of the formulation with an additive package.
(a) Not an official ISO category
Anhydrous Fire Resistant Fluids for Evaluation
• Four fluids examined
• Fully formulated (i.e. contain a base oil and performance additive package)
• Based on an ISO-VG-46 classification
• Fluid A
• Polyol oleate ester product known to be a leading fire resistant fluid in the steel processing industry
• Fluid B
• Water soluble PAG
• Fluid C
• Water insoluble PAG
• Fluid D
• Oil soluble PAG (OSP)
Conventional Polyalklyene Glycol Technology
Initiator (ROH) + +/or catalyst∆ PAG
ethylene oxide (EO) propylene oxide (PO)
Typical Synthesis Route to Polyalkylene Glycols
Types of PAGs by chemical family
Reverse block copolymers of EO/PO Homo-polymers of EO
Homo-polymers of PO Block copolymers of EO/PO
Random copolymers of EO/PO
PAGs and OSPs and Their Chemistry
Simplistic schematic of the types of oxides used in designing PAGs
Fluid B
EO/PO co-polymer
Fluid C
PO homo-polymer
Fluid D
PO/BO co-polymer
Physical Properties
Test
Method Fluid A Fluid B Fluid C Fluid D
Base oil Chemistry Trimethylol-propane
trioleate EO/PO co-polymer PO homo-polymer PO/BO co- polymer Kinematic viscosity at 40°C,
mm2/s ASTM
D445 48.2 47.1 47.2 46
Kinematic viscosity at 100°C,
mm2/s
ASTM
D445 10.8 9.8 8.9 8.3
Viscosity Index ASTM
D2270 225 200 174 157
Pour point,
°C
ASTM
D97 -37 -40 -45 -54
Flash point,
°C
ASTM
D92 278 276 274 267
Fire point,
°C
ASTM
D92 325 312 318 305
Density at 15°C,
g/ml ASTM
D7042 0.92 1.03 0.99 0.96
Water solubility at 5% v/v Visual n/s s n/s n/s
Oil solubility at 5% v/v Visual s n/s n/s s
s = soluble; n/s = not soluble
Hydraulic Wear Performance Testing
• Used an Eaton (Vickers) V-104C pump housing and Connestoga ring and vanes
• Explained in ASTM D7043-12
• Modified procedure
• Used 1 gallon reservoir instead of 5 gallons
• Comprehensive cleaning procedure before each run
• Experiment conditions
• Bulk fluid temperature = 65ºC
• Time = 100 hours
• Speed = 1200 rpm
• Pressure = 2000 psi
Test
Method Fluid A Fluid B Fluid C Fluid D Eaton vane pump V-104C,
- total weight loss of ring and vanes, mg
kinematic viscosity at 40°C change,
ASTM
D7043 3.4
14.7
3.3 0.5
3.8 1.4
0.5 1.0
Eaton 35VQ25A Performance Test on Fluid D
Result
Average cartridge wear, mg 18
Viscosity change, % 1.0
Water, before/after, % 0.07 / 0.05
Acid number before/after, mg KOH/g 0.19 / 0.24
Phosphorus, before/after, ppm 137 / 117
Iron, before/after, ppm <1 / <1
Zinc, before/after, ppm 2 / 6
Tin, before/after, ppm <1 / <1
Calcium, before/after, ppm 6 / 7
Copper, before/after, ppm <1 / <1
Oxidation Testing
Test
Method Fluid A Fluid B Fluid C Fluid D
RPVOT, minutes ASTM
D2272 177 1145 1297 966
Blown air oxidation
- KV100 change after 13 days, % - AN change after 13 days, mg
KOH/g
- KV100 change after 70 days, % - AN change after 70 days, mg
KOH/g
ASTM D2893B modified
-13.0 2.0 20.2
2.5
8.6 0.4 11.9
1.5
n/d 0.6
0.14 1.9 0.16
• Measured in two ways
• Rotary Pressure Vessel Oxidation Test (RPVOT)
• Blown air oxidation
Air Release
• Measurements made at 50ºC using ASTM D3427-12
• Entrained air is known to result in sponginess and lack of sensitivity of the controls in hydraulic systems
Test Method Fluid A Fluid B Fluid C Fluid D Air release at 50°C,
minutes ASTM
D3427 7 9 8 <1
Air release times of commercially available hydraulic fluids (ISO-VG-46)
Additional Performance Properties
Test Method Fluid A Fluid B Fluid C Fluid D
Ester PAG PAG OSP
Base oil chemistry TMP trioleate EO/PO
co-polymer PO Homo- polymer
PO/BO co-polymer Ferrous corrosion ASTM
D665A
pass pass pass pass
Copper corrosion ISO-2160 1b 1a 1b 1a
Demulsibility, ml/ml/ml
(minutes) ASTM
D1401 40/38/2 water soluble poor 41/39/0 (20)
Four ball anti-wear, mm ASTM
D4172 0.36 0.55 0.50 0.31
Fire Resistance
• Assessment often made based on a range of tests
• Spray Flammability
• Hot Manifold Ignition
• Hot Channel
• Wick Flame
• Soaked Cube test
• Fire point and flash point are also relevant
• Examined performance of Fluids A-D with two tests
• Stabilized Flame Heat Release method
• Hot Manifold Ignition test
Fire Testing Results
RI Value ISO-15029-2
RI Factor ISO-15029-2
Manifold ignition test
(ISO14935) Phosphate ester
(reference) 28 Class F >700
Fluid A 5 Class H 373-425
Fluid B 11 Class H 342-373
Fluid C 12 Class H 342-373
Fluid D 10 Class H 342-373
(a) 7thLuxembourg Report 3.1.3.6. The ignitability factor (RI) is graded into ranges with the least flammable having a RI >100
Ignitability Values (RI)
Conclusions
• Examined three HFDU chemistries
• Synthetic ester
• Excellent VI and good low temperature properties
• Poor oxidation performance when compared to the PAGs and OSP fluids
• Viscosity deterioration after vane pump test
• Two PAGs (water soluble and water insoluble)
• OSP
• Has significantly lower air release
• Demonstrated good wear performance and excellent stability in Eaton 35VQ25A vane pump test
• OSP did not show any significant difference from PAGs in terms of fire resistance based on Stabilized Flame Heat Release method and Hot Manifold test
• OSPs have better hydrocarbon compatibility and superior oxidation and air release properties may lead to it being a better practical choice for future PAG-based fire resistant hydraulic fluids
• Further research is needed to determine suitability of OSPs for fire resistant hydraulic applications
Thank You
