TURBINES

Irfan Ahmed

Operations Department

INTRODUCTION

• What is a turbine???• A turbine is a rotary engine that extracts

energy from a fluid flow and converts it into useful work.

TURBINE GENERAL TYPES

• STEAM TURBINE• GAS TURBINE• WIND TURBINE• WATER TURBINE

TURBINE OBJECTIVE

• Turbines are called as “Work Horse” of any process plant.

• These are major prime movers for;A. Compressors.

B. Pumps.

C. Blowers.

D. generators

CLASSIFICATION OF TURBINES

• IMPULSE TURBINE• REACTION TURBINE• CONDENSING TURBINE• BACK PRESSURE TURBINE

BASIC PARTS OF TURBINE

• TURBINE CASING.• ROTOR SHAFT & TURBINE WHEEL • NOZZLES• ROTARY / STATIONERY BLADES• LABYRINTH PACKING / DIAPHRAMS.• PACKING BOXES• BEARINGS

TURBINE AUXILIARIES

• LUBE OIL SYSTEM• BARRING OR TURNING GEARS• TRIP THROTTLE OR MAIN STOP VALVE• OVER SPEED TRIP DEVICE• GLAND SEAL SYSTEM• LUBE OIL PURIFIER

TURBINE AUXILIARIES

• GOVERNORSa) Direct acting fly ball governor

b) Hydraulic governor

c) Oil relay governor

• GOVERNORS & CONTROL SYSTEMa) Sensing element

b) Transmitting element

c) Correcting element

TURBINE AUXILIARIES

• TURBINE GOVERNINGa) Throttle governing

b) Nozzle governing

c) Bypass governing

• SINGLE VALVE & MULTI VALVE

IMPULSE TURBINE

• A turbine that is driven by jets direct against the blades• An impulse turbine has fixed nozzles that converts the

pressurized fluid flow into high speed jets. These jets contain significant kinetic energy, which hit the rotor blades and convert it into shaft rotation as the steam jet changes direction.

• As the steam flows through the nozzle its pressure falls from inlet pressure to the exit pressure (atmospheric pressure, or more usually, the condenser vacuum). Due to this higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very high velocity.

IMPULSE TURBINE

IMPULSE TURBINE

REACTION TURBINE

• A turbine with blades arranged to develop torque from gradual decrease of steam pressure from inlet to exhaust

REACTION TURBINE

• In the reaction turbine, kinetic gas energy is converted to shaft power by decreasing the velocity of the gas and lowering gas pressure

• As gas enters from the left of the blade section and travels across the blade surface, there is a decrease in pressure on the upper surface, and an increase in pressure on the lower surface. As the gas leaves the trailing edge there is a decrease in gas velocity, pressure, and a downward angle resulting in a lifting or reaction force.

REACTION TURBINE

• The steam is directed to flow along the blades, thus causing the blades to rotate because of the reaction force more than the impulse force.

• The reaction turbine has a nozzle design that is incorporated on its blades itself, thus reducing space and making it more compact, as no fixed nozzles were required.

• The only constraint here was that the design of the nozzles on the blades was a bit complicated.

REACTION TURBINE

REACTION TURBINE

IMPULSE VS REACTION

CONDENSING TURBINE

• Inside a condensing turbine - the steam expands below the atmospheric pressure and then "condenses" while heating the cooling water in a condenser. 

• After the steam exits the outlet of the condensing turbine, the steam's pressure is so low, it is no longer available for providing power for industrial applications. 

BACK-PRESSURE TURBINE

• Back pressure steam turbines are a type of steam turbine that is used in connection with industrial processes where there is a need for low or medium pressure steam.

• The high pressure steam enters the back-pressure steam turbine and while the steam expands - part of its thermal energy is converted into mechanical energy. The mechanical energy is used to run an electric generator or mechanical equipment, such as pumps, fans, compressors etc.

• The outlet steam leaves the back-pressure steam turbine at "overpressure" and then the steam returns to the plant for process steam application such as heating or drying purposes.

STEAM TURBINE

• A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion