complete oil analysis
TRANSCRIPT
ANALYSIS & TESTING OF
FUEL OIL LUB OIL
INSULATING OIL &
HYDRAULIC FLUIDS
DIFFERENT TYPES OF OILS USED IN POWER PLANT
• FUEL OIL
• LUBRICATING OIL
• FIRE RESISTANT FLUID
• INSULATING OIL or TRANSFORMER OIL
FUEL OIL
• FUEL OILS BEING USED AT POWER STATIONS
- LDO
- HSD
- FO (FURNACE OIL)
- LSHS (LOW SULPHUR HEAVY STOCK)
LDO & HSD
• LOW VISCOSITY• LOW FLASH POINT• COSTLY• NO NEED OF HEATING• NO STEAM REQUIRED• CV ~10720 KCAL/KG• IDEAL FOR STARTING OF BOILER FROM
COLD
FURNACE OIL• MUCH HIGHER VISCOSITY THAN LDO OR HSD
• REQUIRES HEATING AT THE TIME OF UNLOADING & PUMPING
• PREHEATING UPTO 110 DEGC FOR USE
• BETTER ATOMISED WITH STEAM
• COMPARATIVELY CHEAPER THAN LDO & HSD
• CV ~ 10270 KCAL/KG
**LSHS- HIGHLY VISCOUS, CHEAPER THAN FO
Parameters Monitored of Fuel oil
• Standard: IS 1593/1971, Grades: LV-MV-HV
• API gravity: 12 sp. 0.986 at 15 degc
• Viscosity- 80-120-370 cst at 50 degc
• Flash point- 66 degC (min)
• Pour point
FO Monitoring…• GCV: 10270 kcal/kg
• Total Sulphur : 3.5-4.0-4.5% by weight
• Water Content
• Ash content • Sediments
FUNCTIONS OF FO
• Coal fired units contains oil burners having capacity of 15-20%
• Ignition energy to light off coal burners
• Stabilization of coal flame at low loads
• Safe and reliable heat input source during light up of boiler
PROPERTIES OF LUB OIL TO BE CHECKED
• KINEMATIC VISCOSITY: The Redwood viscometer determines the time usually expressed in sec required for a standard volume of oil to flow through a standard orifice at specified pr. & temp.
• Kinematic viscosity= const. x time
• Moisture content: By Crackle test or by Karl Fischer titration method
• Mechanical Impurities: A fixed volume of oil is dissolved in a solvent like Toluene or Pet. Ether and passed through pre weighed 45 micron filter paper.
MI is determined from difference in weight
• Foaming Characteristics• Copper strip corrosion• Emulsion Characteristics• Cloud and pour point• Acidity• Oxidation Characteristics • Flash point
PROPERTIES OF LUBRICATING OIL TO BE CHECKED
LIMIT OF DIFFERENT LUBE OIL
S.No Equipment Stage
Name of oil
Moisture (ppm)
MI(ppm)
Viscosity (cst)
1 MOT/BFP/ ID/FD
I SERVO PRIME-32
150 50 27.6-36.3
2 PA FAN I SP-68 150 50 60.8-79.2
3 CT FAN/ASPH
I SERVO SYSTEM-121
200 500 118-124
4 MILL GEAR HOUSING
I SERVO MESH SP-320
1000 0.1% 320-350
LIMIT OF DIFFERENT LUBE OIL
S.No
Equipment Stage
Name of oil
Moisture (ppm)
MI(ppm)
Viscosity (cst)
1 TURBINE II DAPHANE SUPER TURBINE-46
100 50 41.4-50.6
2 PA FAN/SAPH
II SERVO CYCLE-660
100 50 615-680
3 FD/ID II SERVO PM-68
100 50 64-72
4 TDBFP BRG & COUPLING
II SERVO PM-46 T
300 50 43-48
5
MDBFP II SERVO SYSTEM-HLP32
300 50 29-39
6 MAIN MILLLUBE UNIT
II SERVO SYSTEM-460
500 500 440-500
FIRE RESISTANT FLUID
FIRE RESISTANT FLUID
• FRF is known as phosphate ester hydraulic fluids.
• They are used in 500 MW turbine control system
• They are fire resistant, exhibit good resistance to oxidation hydrolysis, adequate air release and low foaming properties when compared to petroleum oil.
PARAMETERS OF FRF MONITORED
• Water Content-Potential for Hydrolysis• Fluid Cleanliness/ Particle Count• Total Acid No-Hydrolysis that has occurred• Mineral oil content• Air release• Viscosity• Resistivity
FRF POLISHING UNIT
• Mechanical filter and strainers removes mechanical impurities
• Fuller earth and activated alumina treatment to remove acidic ions. They acts as ion exchangers.
• Air drier or desiccant breather to remove moisture-moisture filter.
LIMIT OF DIFFERENT PARAMETERS
S.N Parameter Test Method Permissible Limit
1 Viscosity ASTM D-445 30-50 cst
2 Acid Number ASTM D-974 0.2 mg KOH/gm
3 Water Content ASTM D-1744 1500 ppm
4 Sediments AFNORE-48652 5 mg/100 ml
5 Particle Count ASTMF-662/322
Class 16/13
INSULATING OIL
USE OF INSULATING OIL
• Insulating oils are derived from mineral oil.
• Insulating oils are used in transformers, reactors switchgear and cables.
• It quenches arcs when switching.• Prevents glow discharge.• Act as a cooling agent.
AGEING OF OIL DURING OPERATION
• Increased temperature.• Absorption of gases mainly oxygen.• Absorption of water from atmosphere.• Ageing through contacts with metal
plates like copper and iron• High temperature decomposition.
• Dielectric breakdown test.
• Dielectric dissipation factor or tan-d.
• Specific resistances.
• Water content test.
• Acidity Test.
PARAMETERS OF INSULATING OIL MONITORED
RECONDITIONING OF INSULATING OIL
• Reconditioning of oil means removal of water and solid particles from oil.
• This is done by using several available type of filters, centrifuge and vacuum dehydrators.
• Filter removes mechanical impurities.• The centrifuge is used when there is large
amount of water or other contamination present.
• Vacuum dehydrator removes water and dissolved gases.
Condition Monitoring of HV Transformers and Reactors
by DGA technique
Degradation of insulating oil
• Electrical discharges or thermal stresses in the oil or solid insulator of an oil filled transformer produces gases.
• The most significant gases produced are hydrogen, methane, ethane, ethylene and actylene.
• The relative quantity of various gases depends on the energy available.
GASES GENERATED UNDER DIFFERENT CONDITION
S.N Phenomenon Gases Generated
1 Partial discharge H2 gas (mainly)
2 Little heating CH4,H2
3 Low temp. hotspot CH4
4 Moderately high temp hotspot
C2H4,C2H6
5 Very high temp hotspot C2H2 in significant amount.
Steps involved in D G Analysis• Sampling of oil - Stainless steel oil
sampling containers of capacity up to 1000 ml with needle valves and tube adaptors at both ends can be used for sampling.
• Gas Extraction from oil – Dissolved gases are extracted by degassing flask attached with a vacuum pump assembly. The extracted gas is then compressed to atmospheric pressure and volume of the gas is measured.
Steps involved in D G Analysis
• Analysis of gas extracted- The gas extracted can be analyzed by a Gas Chromatograph fitted with a thermal conductivity cell detector. The carrier gas is helium. The column used is poropak N and Molecular sieve 5A.The gases determined are Hydrogen, oxygen, nitrogen, methane, ethane, ethylene, acetylene, propane, propylene, CO, CO2 etc.
HYDRAULIC FLUIDS
MINERAL OIL HYD FLUIDS
• SOLUBLE IN WATER, FORMING EMULSIONS
• USED WHERE NOT MANY MOVING PARTS ARE INVOLVED
• CHEAP
• IF LEAK OCCURS, PRESENT A DEFINITE FIRE HAZARD AT ELEVATED TEMP
WATER/GLYCOL HYD FLUID
• BETTER OILLINESS THAN MINERAL OIL HF
• ARE REASONABLY FIRE RESISTANT
• FLUID BECOMES THICKER & STICKY AT HIGH TEMP
• WATER CAN BE ADDED TO RESTORE ITS ORIGINAL CONSISTENCY
• MORE EXPENSIVE THAN THE SOLUBLE MINERAL OIL HF
SYNTHETIC HYDRAULIC FLUID
• MAN-MADE PRODUCT
• CHEMICAL NAMES SUCH AS CHLORINATED HC & PHOSPHATE ESTERS
• HIGH RESISTANCE TO FIRE
• USED IN BOILER DAMPERS & OTHER SYSTEMS WHERE HIGH TEMP ARE ENCOUNTERED
• COSTS ABOUT 8 TIMES AS MUCH AS MOHF
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