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Rankine Cycle. Turbine control. The principle features of the TCS. Speed Control. Inlet/Admission Pressure Controller. Load Control. Turbine Stress Influence. Frequency Influence. Valve Lift Control. 1- Speed Control. Steam turbine governing. Throttle governing. Nozzle governing.
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The principle features of the TCS • Speed Control. • Inlet/Admission Pressure Controller. • Load Control. • Turbine Stress Influence. • Frequency Influence. • Valve Lift Control.
1-Speed Control • Steam turbine governing • Throttle governing. • Nozzle governing. • By pass governing. • Combination governing. • Emergency governing.
Emergency governing • When the speed of shaft increases beyond 110%. • Balancing of the turbine is disturbed. • Failure of the lubrication system. • Vacuum in the condenser is quite less or supply of coolant to the condenser is inadequate.
Types Of Condensation • Film-wise condensation: condensed liquid wets the surface and • forms a film covering the entire surface. • Drop-wise condensation: surface is not totally wetted by the • saturated vapor, and the condensate forms liquid droplets that fall. • from the surface. • Compared to film-wise condensation, drop-wise condensation has a greater. • surface heat-transfer coefficient as it has a greater area exposed to the. • saturation vapor.
Stages in Condensation • De-superheating of the hot gas. • Condensing of the gas to liquid state and release of the latent heat. • Sub-cooling of the liquid refrigerant.
Types of Condensers • Water-cooled condensers. • Double-tube condenser. • Shell-and-tube condenser. • Air-cooled condensers. • Evaporative condensers.
Condenser Cleaning Program • Cleaning the condenser coils will ensure: • maximum efficiency. • help prolong the life of the unit. • protect your Pumps from premature failure. • maximize your overall investment.
Steps Of Cleaning • First, and most importantly, turn off the power to the unit. • Remove any visible grass. • Brush in the same direction as the slots between the fins . • You can do a better job if you remove the guard grill, which protects the coil. • Wear a dust mask to avoid breathing the dust. • Then put on a pair of rubber gloves and spray biodegradable outdoor coil cleaner into the coil. • . Wait five or ten minutes and flush the coil with a gentle water spray. Use a gentle spray because a strong spray could bend the aluminum fins. • That’s it! Simply restore the power to your AC unit and you’ll have a much smoother running air conditioner.
Feedwater heater Preheating feedwater before entering the boiler.
How feedwater heater works?! • We use a stream of the steam to heat the feedwater instead of using fuel. • The extracted steam comes from the turbine. • We extract steam at specific conditions and pressure to gain good output work from turbine.
Open feedwater heater Advantages Disadvantages • Simple. • Inexpensive. • High rate ofheattransfer. • We need pump for each feedwater heater.
Closed feedwater heater Advantages Disadvantages • We don’t need a pump for each feedwater heater because of different pressure. • More complex. • More expensive. • Less heat transfer.
Haw we can increase the rate of heat transfer in closed FWH ?!
Types Of Boilers • By Method of steam generation : • Fire tube boiler. • Water tube boiler.
Shell Boilers • Lancashire boiler. • Economic boiler (two-pass, dry back). • Economic boiler (three-pass, wet back). • Packaged boiler. • Reverse flame / thimble boiler.
Lancashire boiler • Highly efficient. • Less used nowadays due to high expenses. • Use economizer at the back to increase efficiency.
Economic boiler (two-pass, dry back) • about half the size of an equivalent Lancashire boiler. • higher thermal efficiency.
Economic boiler (three-pass, wet back) • thinner metal tubes were introduced. • the heat transfer rates to be improved. • the boilers themselves to become more compact.
Packaged boiler • Size is as small as possible … (save material). • less heat is lost to the environment. • Minimize the amount of floor space needed.
