oil _analysis15 sat class

7/30/2019 Oil _analysis15 Sat Class

1/29

ANALYSIS & TESTING

OF

FUEL OIL

LUB OILINSULATING OIL

&

HYDRAULIC FLUIDS


2/29

ANALYSIS & TESTING OF OI LS

Different Types Of Oil Used In Power Plant

Fuel Oil

Lubricating Oil

Fire Resistant Fluid

Insulating Oil Or Transformer Oil


3/29

FUNCTIONS OF FO

Coal fired units contains oil burners havingcapacity of 15-20%

Ignition energy to light off coal burners

Stabilization of coal flame at low loads

Safe and reliable heat input source during lightup of boiler


4/29

1. FUEL OILS

LOW FLASH POINT FO LOW FLASH POINT FO

LDO & HSDFURNACE OIL

PROS CONSCONSPROS

Low viscosity

No need of heating

No steam required

Cv ~10720 kcal/kg

CostlyHIGHER VISCOSITY

Requires heating at the

time of unloading &

pumping preheating upto

110 degc for use

Better atomised with steam

Comparatively cheaper than

ldo & hsd

LSHS- HIGHLY VISCOUS, CHEAPER THAN FO

Cv ~10720 kcal/kg

IDEAL FOR STARTING OF

BOILER FROM COLD

COST EFFECTIVE


5/29

Parameters Monitored of Fuel oil

Viscosity Index-- Rate of change of viscosity w.r.t temperature.=>Higher

the V.I better the oil will be and High V.I oil does not become thin with the

rise of temperature

LIMIT 80-120-370 cst at 50 0C.

Flash point-- Temperature at which an oil on heating under prescribedconditions gives off sufficient vapours to form mixture with the air, ignites

on the introduction of the test flame from std. apparatus. Indicates degree of

safety on storage,transpotation

LIMIT : 66 0C (min)

Pour point--It is lowest temp. which is multiple of 3C at which the oil

ceases to flow under prescribed conditions & is reported 3C higher than

it.Signifies the pump ability of the oil at low temp.


6/29

GCV: 10270 kcal/kg

Total Sulphur : Sulphur causes wears in engine as result of its combustion by

products and hence is undesirable than the stipulated limits

LIMIT : 3.5-4.0-4.5% by weight

Water Content --Being good conductor of electricity and hence always better tokeep minimum possible ppm content.

Ash content-- Non combustible material remaining after a sample of the product

is completely burned. It could be dust , dirt or any other foreign matter

Oxidation stabilityIt is important to determine the life of the oil as oxidation

produces sludge ,acid and other deliterious products.


7/29

A LUBRICANT CAN BE DEFINED AS A SUBSTANCE WHICH

IS ABLE TO REDUCE FRICTION, WEAR AND SURFACE

DAMAGE RESULTING UPON TWO SOLID SURFACES IN

RELATIVE MOTION

LUBE OIL OR LUBRICANT


8/29

PROPPERTIES OF LUB OIL TO BE

CHECKED

KINEMATIC VISCOSITY: The Redwood viscometerdetermines the time usually expressed in sec required for astandard volume of oil to flow through a standard orifice atspecified pr. & temp.

Rate of change of viscosity w.r.t temperature.

Higher the V.I better the oil will be.

High V.I oil does not become thin with the rise oftemperature.

Kinematic viscosity= const. x time


9/29

SENSORY TESTSAppearance-- It is the simplest test to check whether the oil is clear and bright not

hazy and cloudy. Hazy and cloudy appearance will indicate water

contamination. Check the suspended impureties, foaming etc.

Colour--This test is useful only with light coloured products. Darkeing in colourindicate either oxidation or contamination from external sources.

Odour--Used oils will normally have bad or oily odour, oxidized oils will have

burnt or pungent odour.


10/29

Moisture content: By Crackle test or by CarlFischer titration method


11/29

Mechanical Impurities:A fixed volume of oilis 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


12/29

Foaming characteristics determination-- Foaming tendency of oil due to trapping ofair in it. Trapping air in the oil will result uneven spreading the oil film on themoving parts resulting to damage of the machinery

Copper strip corrosion-- covers the corrosiveness of the petroleum products tocopper

Emulsion characteristics--Ability of petroleum oil to separate from water subject towater contamination turbulence

Cloud and pour point

Acidity-- quantity of base expressed in mg. Of KOH required to neutralize all the

acidic constituents present in one gram of sample.Expressed in mg. KOH / gm. Ofthe sample

Oxidation characteristics

Flash point--

PROPERTIES OF LUBRICATING OIL TO

BE CHECKED


13/29

LIMIT OF DIFFERENT LUBE OILS.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


14/29

LIMIT OF DIFFERENT LUBE OIL

S.No Equipment Stage Name ofoil

Moisture(ppm)

MI(ppm)

Viscosity(cst)

1 TURBINE II DAPHANE

SUPER

TURBINE-46

100 50 41.4-50.6

2 PA FAN/SAPH II SERVOCYCLE-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 MILL

LUBE UNIT

II SERVO

SYSTEM-460

500 500 440-500


15/29

HYDRAULIC OILS

Soluble in water, forming

emulsions

Used where not many

moving parts are involved

Cheap

If leak occurs, present a

definite fire hazard atelevated temp

MINERAL OILWATER/GLYCOL OIL

SYNTHETIC HYDRAULIC

FRF

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

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 Mineral oil

Hydraulic Fluid


16/29

FIRE RESISTANT FLUID

FRF is known as phosphate ester hydraulic fluids.

They are used in 500 MW turbine control system

PROPERTIES:

They are fire resistant

exhibit good resistance to oxidation hydrolysis,

adequate air release and

low foaming properties.

These properties are when compared to petroleum oil


17/29

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 Value-- Gives the measure of the ability of an oil to separate

entrained air. Trapped air tends to interfere with transmission of heat there byincreasing the operating temperature and also promoting the oxidation of oil.

Viscosity-

Electrical Properties-- Dielectric strength maximum voltage which oil canstand. Higher the value better the oil. Dielectric dissipation factor( bdv ) it isthe tangent of the angle delta by which the phase difference between theapplied voltage and resulting current deviate from tt/2 radian when dielectric ofthe capacitor consists of the insulating oil. Lower the tan delta better the oil.Specific resistance is the ratio of the dc potential gradient in volts percentimeter paralleling the current flow with in specimen to the current densityin amp. Per sq.Cm at a given instant time


18/29

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.


19/29

LIMIT OF DIFFERENT PARAMETERSS.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


20/29

INSULATING OIL


21/29

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.


22/29

Dielectric breakdown test.

Dielectric dissipation factor or tan-d.

Specific resistances.

Water content test.

Acidity Test.

PARAMETERS OF INSULATING OIL

MONITORED


23/29

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.


24/29

RECONDITIONING OF INSULATING OIL

Reconditioning of oil means removal of water and solidparticles 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 orother contamination present.

Vacuum dehydrator removes water and dissolved gases.


25/29

CONDITION MONITORING OF HVTRANSFORMERS AND REACTORS BY

DGA TECHNIQUE


26/29

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 acetylene.The relative quantity of

various gases depends on the energy available.

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.


27/29

STEPS INVOLVED IN D G ANALYSIS

Sampling of oil - stainless steel oil sampling containers ofcapacity 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. Theextracted gas is then compressed to atmospheric pressure andvolume of the gas is measured.

Analysis of gas extracted- The gas extracted can be analyzed

by a Gas Chromatograph fitted with a thermal conductivitycell detector. The carrier gas is helium. The column used isporopak N and Molecular sieve 5A.The gases determined areHydrogen, oxygen, nitrogen, methane, ethane, ethylene,acetylene, propane, propylene, CO, CO2 etc.


28/29

CHEMISTRY QUESTIONS Q1. The analysis of transformer oil is carried out by

a. BGA b. CGA

c. TGA d. DGA

Q2. FRF oil is used in

a. governing system b. Combustion system c. Lubrication d none of these

Q3. Crackle test is used to test

a. MI of oil b. Moisture of oil

c. oil in water d. viscosity of oil

Q4. GCV of fuel oil is in the range

a. >10000kcal/kg b. between 3000 to 4000kcal/kg

c. between 4000 to0 10000kcal/kg d.


29/29

THANK YOU

oil _analysis15 sat class

Documents