Presentation of Pressure

7/31/2019 Presentation of Pressure

1/44

SUBMITTED BY:-

PARUL GARG

ROLL NO.D-5104

ECE DEPARTEMENT

SUBMITTED TO:

DEPTT. OF ELECT & COMM.


2/44

First it was to be set up at G.N.D.T.P. but air forcepersonal restricted it & it was shifted to 22km apartfrom Bathinda city & named as GURU

HARGOBIND THERMAL PLANT. Its purpose is to produce electricity.

The factors favoring the installation are:-

To fulfill power demand.

Low initial cost & low generation period ascompared to hydroelectric generating center.

Good railway connection.

It meets 20-25% of power requirements in Punjab.

Companies involved are TATA HONEYWELL &BHEL.


3/44

Total no. of units are four & forth is standby.

First two units are commenced in 1990s &210MW electricity is generated by each unit.

Third unit is commenced on 14 April 2008 &produces 250MW electricity.

Fourth unit is still standby as commencement offourth unit is waited in July & it will produce250MW electricity.

Its overall cost is 35 crores.

Its overall efficiency is 95%.

It distributes power from Barnala Sub distributionMansa, Bathinda, Delhi, Ludhiana as per

requirement.


4/44

COAL HANDLING

SYSTEM

CWSYSTEM

TURBINE AND

GENERATOR

SECTIONBOILER SECTION

CONDENSATION

CYCLE

STEAM

ELECTRICITY

ASH HANDLING

SYSTEM


5/44


6/44

MILLS

The coal in pulverized state does not get burntin boiler so coal from rail wagon is sent to millswhere it is crushed & formed into form which canbe used in boiler.

Its operating parameters are:-

Designed air flow per mill is 53.89 tons/hr.

Recommended mill outlet temperature is 85C ,ifbelow 60-80C then it may not dry the coalsufficiently and may cause choking.

If temperature exceed from 95C then it leadto mill on fire.


7/44

PRIMARY AIR FANSFirstly for crushing of coal in mills hot air isprovided by PA fans.

Secondly the coal from mills in powder form is

pushed to boiler furnace with the help of hotout steam supplied by PA fans.

Number of fans are two per boiler.

Its capacity is 70 cubic meter/sec.

Its fan speed is 1480 R.P.M.


8/44

FORCED DRAUGHT FANS

For combustion of fuel, air is required which iscalled as secondary air and it is provided by

FD fans.Number of fans are two per boiler.



INDUCED DRAFT FAN

It is used to suck the gases out of the furnace& throw them into the stack . The temperature

at which it work is 125-250 degree centigrade. Number of fans are three per boiler.




9/44

TURBINE & GENERATOR

There are three turbines & a generator havingcommon shaft.

When steam from boiler falls on blades ofturbine then turbine & generator rotatesresulting in production of electricity.

Its rated output is 210MW.Its rated speed is 3000 R.P.M.

Inlet steam pressure is 150kg/cm2.

Inlet steam temperature is 535 degreecentigrate.

Weight of turbine is 475t approximately.


10/44

CONDENSATE CYCLE

Steam after doing the useful work in turbine &generator comes to condenser for cooling & can be

reused in the process. Then it is pumped todeareater by CEP through different heating stages& these are:-

GLAND STEAM COOLER

DRAIN COOLERLP HEATERS

HP HEATERS

The approximate temperature rise of condensateafter passing through above heating stages is from40/45 at hot well to 166C at the deaerator ( at fullload).


11/44

GLAND STEAM COOLER

Its basic purpose is to increase the temperature

of water. It increases the temperature by 2degree centigrade.

It is single pass heat exchanger & having tubes

which condensate the water.

Number of zigzag shaped tubes are 313.

Material used for tubes is stainless steel.

LP HEATERS

After passing from GSC it goes to LP heaters

Where temperature increases.


12/44

DRAIN COOLER

If temperature of water rises beyond in LP

heaters then water goes to this & it decreasesthe temperature.

There are 510 straight tubes & material used

for it is Brass.

Material for tube plate & shell is Carbon Steel.

Tubes surface area is 35m .

Water passing from here goes to LP heaters &

HP heaters and goes to dearator.


13/44

DEARATOR

The water coming from drain cooler

contain certain gases like carbon dioxide,oxygen, ammonia etc.

So this water cannot be reused forprocess of plant.

So to prevent from internal corrosion weuse DEARATOR.

Its design temperature is 250 C & it

operate at 170 C.

Its design pressure is 7.4 Kg/cm & itoperate at 6.8 Kg/cm.


14/44

BOILER FEED PUMP

It is the important auxiliary of the powerhouse.

It takes supply of water from Dearator &

supply to boiler drum.

Pump type is FK6D30.

Its direction of rotation is anti clockwise.

Its input power is 3008.8kw.

Its speed is 5145 R.P.M.

Its efficiency is 82%.


15/44


16/44

INTRODUCTION

In every process industry there are so manyparameters like pressure, temperature, flow,

level etc that are to be measured & controlled.

So measurement system is required to measure

all these parameters. Operation of measurementsystem can be described in terms of functional

elements which are as follow:-

Primary sensing element Variable conversion element

Data presentation element


17/44

The primary sensing element is the most

important part of the measurement system. It

includes a sensor & a transducer.

Sensor is a device that detects a measurand orquantity to be measured.

Its output goes to transducer.

Transducer converts signal into electrical signal.


18/44

Depending upon the quantity to be

measured different types of sensors are:-

Pressure sensors

Flow sensors

Temperature sensors

Level sensorspH sensors

SENSORS


19/44

PRESSURE SENSORS

Pressure measurement is most important

industrial measurement.

Its principle is applied in other

measurement like temperature, flow, liquid

level.

Pressure =force/area, N/m2.

It has same unit as stress.


20/44

Pressure can be measured as absolute, gauge ,

differential pressure.

Absolute pressure is the absolute value of theforce per unit area on the containing walls by a

fluid.

Gauge pressure is the difference between

absolute pressure & atmospheric pressure.

Differential pressure is the difference between

two pressure.

Pg =Pa- PsPd= P1-P2


21/44

CLASSIFICATION OF PRESSURE

SENSING DEVICESCLASSIFICATION

OF PRESSURESESING DEVCE

Depending on

principle of

working

Depending on

Pressure range

Mechanical ElectroMechanical Electronic High Pressureup to 70000 Mpa Low In Micro

Manometer

Elastic Element

Potentiometeric

Transducer

Strain Gauge

Photo Electric

Transducer

Piezoelectric

Transducer

Mcleod gauge

Knudsen Gauge

Praini Gauge

Mechanical

Electro

Mechanical

MECHANICAL INSTRUMENT


22/44

MECHANICAL INSTRUMENT:-

Pressure measurement is made bybalancing the unknown force produced by

pressure under measurement like manometer,elastic element.

ELECTROMECHANICALINSTRUMENT:-

Employ mechanical means for detectingpressure & electrical means for indicating likestrain gauge.

ELECTRONIC INSTRUMENT:-Physical changes caused by pressure

are detected & indicated by electronic meanslike gauges used for vacuum measurement.

MANOMETERS


23/44

MANOMETERS

The principle of working is that the unknownpressure is balanced against gravitational forceof liquid heads.

Manometer bodies are made up of brass, steel,aluminum & tubes are made up of Pyrex.

Its range is low vacuum to 0.1 MN/m2.

Its types are:-

U-tube

Well type

Inclined type

Ring type

Micro manometer

WHICH ONE IS THE BEST MANOMETERIC FLUID


24/44

WHICH ONE IS THE BEST MANOMETERIC FLUID

WATER OR MERCURY?

Cheap & convient is water but it has following

drawback..It evaporates and therefore, the gauge needs frequent

topping off.

It is also transparent so it makes readability difficult, adie has to be used to make it coloured.

But mercury is best suited for this.

Other manometeric fluids are:

Transformer oil

Aniline

Carbon teterachloride

Bromophome


25/44

U-TUBE MANOMETER

It is used for measurement of liquid & gas

pressure. The manometer is filled with a manometeric

fluid whose specific gravity is known.

The difference between the pressures on twolimbs of the Manometer is a function of h.

So the pressure is

P=P1+ghf= P2 + ghmP = P1-P2 = gh(m- f)


26/44

They are available with the ranges up to 40kN/m2


27/44

They are available with the ranges up to 40kN/m2.

Its maximum operating pressure is up to 3MN/m2.

Its dynamic response is poor.

But in this there is a small change in pressure, so one

leg of this is converted into well shape & named as

Well type manometer.

But in Well type again there is small change in the legof Well type manometer.

So then the vertical leg is placed at some inclination

angle which is named as Inclined tube manometer & if

there is small change in pressure in the well causeslarge change in the measurement level of liquid in the

inclined leg. It is shown in the figure.


28/44


29/44

They have much higher sensitivity then

that of vertical limited. They are available in ranges from 0-10mm

of water to 0-100mm of water using water

as manometeric fluid & up to 0-1250mm of

mercury using mercury as manometeric

fluid.


30/44

ELASTIC PRESSURE ELEMENTIts principle of working can be explained through flow chart.

Displacement caused by pressure

Displacement actuates Pointer on scale

If

Signal isdirect

Measure

Secondary Transducer converts signal into electrical

form

Show the value ofPressure

Electrical signal is shown as O/P

No


31/44

TYPES OF ELASTIC ELEMENT

TYPES OF

ELASTIC

ELEMENTS

BOURDON

TUBEBELLOWS DIAPHRAGM

C - SHAPE SPIRAL HELICAL


32/44

BOURDON TUBE


33/44

In C-type, geared sector & pinion arrangement is

used for magnification of the output & pointing

on the scale. But it led to backlash error & itsaccuracy is poor which is + 1%.

So to improve this spiral or helical type is used.

In spiral type displacement is increased byincreasing the number of coils & there is no

need of further magnification.

In helical displacement is larger than spiral type.

Bourdon tubes are made up of brass, stainless

steel, bronze, monel, phosphorous bronze, alloy

steel.


34/44

BELLOWS

Metallic bellows are having series of circular

parts joined in such a manner that they are

contracted or expanded axially by change in

pressure. Material used should be flexible, ductile.

For construction of bellows brass, bronze,

beryllium etc can be used.


35/44


36/44

Bellows can be used for measurement of

differential, absolute, gauge pressure . It is

shown in fig.


37/44

LOW PRESSURE SENSING

DEVICES

It is used for measurement of low

pressure.

For these measurements gauges are

used.

They are:-

McLeod gauge

Knudsen gauge

Pirani gauge

Ionization gauge


38/44

MCLEOD GAUGE


39/44

STRAIN GAUGE

Its principle of working is piezoresistive

effect.

In this if a metal conductor is stretched or

compressed its resistance changes on

account of the fact that both length &

diameter of conductor changes which also

led to change in resistivity of conductor.


40/44

SEMICONDUCTOR STRAIN GAUGE:-

These gauges depend for their action upon piezoresistive

effect i.e. the change in value of resistance due tochange in resistivity.


41/44

Material used for these gauges are silicon,

germinum.

It is used for very small strains of the order of0.01 microstrain.

Piezoresistive pressure transducer which have

semiconductor strain gauge are available in

pressure ranges from 15kPa to 350MPa.

For these types of gauges pressure is applied

directly to a silicon diaphragm.


42/44

HOW STRAIN GAUGE IS USED TO MEASURE

PRESSURE ?

Strain gauge can be used to produce anelectrical signal in proportion to the change in

resistance caused by distortion of an elastic

element.

Strain gauges are used in G.H.T.P. for pressure

measurement.


43/44

In this plant measurement of pressure is

done by taking impulse line.

Accuracy is < + 0.25% of calibrated span. Maximum pressure range is 175.4kg/cm2

(approx.) which is BFP common discharge.

Pressure in boiler drum is 150kg/cm2. Minimum pressure is 0.884kg/cm2 which

is in condenser.


44/44

Documents

Presentation of Pressure