Design and Fabrication of Lab Model of Steam

7/31/2019 Design and Fabrication of Lab Model of Steam

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DESIGN AND FABRICATION OF LAB

MODEL OF STEAM TURBINE PLANT

Bilal Ibrahim08-MECH-48

Jawad Ahmed08-MECH-42

Imran Ahmed Khan08-MECH-49

Basit Ali08-MECH-52


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WHATIS STEAM TURBINE?

A steam turbine is a device that extracts thermal

energy from pressurized steam and uses it to do

mechanical work on a rotating output shaft. High-

temperature, high-pressure steam passes through

a nozzle on fixed blades and spurts out andexpands, or has its direction altered into a high-

speed jet that is directed against rotor blades which

spin the shaft to which they are attached, creating

rotational energy. In simple terms, the steamturbine's rotors are turned by the force of the steam

in just the same way that a waterwheel is turned by

the force of the flowing water.


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PLANTLAYOUT


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BASIC PRINCIPLE (RANKINE CYCLE)


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RANKINE CYCLE

Process 1-2: Water from the condenser at lowpressure is pumped into the boiler at high pressure.

This process is reversible adiabatic.

Process 2-3: Water is converted into steam atconstant pressure by the addition of heat in the

boiler.

Process 3-4: Reversible adiabatic expansion ofsteam in the steam turbine.

Process 4-1: Constant pressure heat rejection inthe condenser to convert condensate into water


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THERMAL EFFICIENCYOF RANKINE CYCLE


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HOWTOINCREASETHEEFFICIENCYOFTHERANKINECYCLE?

Lowering the Condenser Pressure

Superheating the Steam to High Temperatures

Increasing the Boiler Pressure

The Ideal Reheat Rankine Cycle The Ideal Regenerative Rankine Cycle


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LOWERINGTHE CONDENSER PRESSURE

Steam exists as a saturated mixture in the condenser at the saturation

temperature corresponding to the pressure inside the condenser. Therefore,

lowering the operating pressure of the condenser automatically lowers the

temperature of the steam, and thus the temperature at which heat is rejected.

The effect of lowering the condenser pressure on the Rankine cycle efficiency

is illustrated on a T-s diagram.


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SUPERHEATINGTHE STEAMTO HIGH

TEMPERATURES The average temperature at which heat is transferred to steam can be

increased without increasing the boiler pressure by superheating the steam tohigh temperatures. The effect of superheating on the performance of vapor

power cycles is illustrated on a T-s diagram. The colored area on this diagram

represents the increase in the net work. The total area under the process

curve 3-3_ represents the increase in the heat input. Thus both the net work

and heat input increase as a result of superheating the steam to a higher

temperature.


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INCREASINGTHE BOILER PRESSURE

Another way of increasing the average temperature during the heat-addition

process is to increase the operating pressure of the boiler, which

automatically raises the temperature at which boiling takes place. This, in

turn, raises the average temperature at which heat is transferred to the steam

and thus raises the thermal efficiency of the cycle.


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THE IDEAL REHEAT RANKINE CYCLE

Expand the steam in the turbine in two stages, and reheat it in

between. In other words, modify the simple ideal Rankine cycle witha reheat process. Reheating is a practical solution to the excessive

moisture problem in turbines, and it is commonly used in modern

steam power plants.


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THE IDEAL REGENERATIVE RANKINE CYCLE


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BOILER

A boiler is a closed vessel in which water or otherfluid is heated. The heated or vaporized fluid exits

the boiler for use in various processes or heating

applications, including boiler-based power

generation, cooking, and sanitation.


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TYPESOF BOILERS

Fire tube Boiler

Water tube Boiler

Electric Boiler


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FIRETUBEBOILERS


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DESIGNED BOILER


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CROSS-SECTIONALVIEW


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ACCESSORIESUSEDINBOILER

Swing check valve

Relief valve


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A bimetallic temperature gauge

Pressure gauge


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Level indicator


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TURBINE

A turbine is a rotary mechanical device that extracts energy

from a fluid flow and converts it into useful work.


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TWO TYPESOF TURBINES

Impulse type

In impulse turbines, high-velocity steam from fixed nozzles impacts the

blades, and this impulse drives the blades forward, causing the rotor to turn.

Reaction Type

In reaction turbines, high-velocity steam from nozzles striking blades also

produces impulse, but the steam jet runs into the blades and the main force

turning the rotor is the reactive force produced by the expansion of steam

flowing off the rotor blades themselves.


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DIFFERENCE


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DESIGNED TURBINE

Design and Fabrication of Lab Model of Steam

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