Thermal Power Generation Plant Components and Cycle

Conventional Thermal Power Plant Operation

Electric power is generated from the heat produced by the combustion of coal or natural gas fuel.

Core Components of the Thermoelectric Cycle

There are many types of boilers. The most commonly used are radiation boilers, so named because the heat energy is primarily transmitted by radiation.

Boiler Structure and Function

Boilers have a burner appropriate for the type of fuel used and a combustion chamber surrounded by innumerable tubes through which water circulates to vaporize.

Reheaters

Reheaters are parts of the boiler designed to eliminate water droplets accompanying the steam to convert it into dry steam.

Economizers and Preheaters

Economizers and preheaters harness the residual heat of the emitted combustion gases (flue gases). They achieve this by preheating the boiler feed water, the fuel, and the air necessary for combustion.

Steam Turbines

Turbines are machines that convert the kinetic energy of the steam into rotational kinetic energy in the rotor. For maximum transformation efficiency, they consist of three parts, supportive of the rotor:

• High pressure section
• Medium pressure section
• Low pressure section

Condenser

To increase the thermodynamic efficiency of the transformation cycle, the water to be vaporized must enter the boiler as a liquid. In the condenser, the steam exhausted from the turbines is condensed before re-entering the boiler to repeat the cycle.

Cooling Tower Functionality

The coolant water serves to cool the condenser. Cooling circuits can be open or closed, depending on water availability. In closed circuits, it is essential to reuse the cold water. In open circuits that use river water, it is necessary, to avoid affecting wildlife, that the water returned to the river has a temperature as close as possible to the river's original temperature. Its operation is very simple: the water is raised and dispersed as a very fine rain to cool it, offering a large surface area for contact with the air circulating in the opposite direction.

Auxiliary Systems

Chimney (Flue Stack)

The chimney creates a draft (negative pressure) within the boiler to circulate the gases released during combustion and evacuate them to the atmosphere. The chimney draft can be:

• Natural: Gas movement is caused by the chimney's geometry.
• Forced: Mechanical drivers (fans) assist the movement.

Feed Water Treatment Room

The smooth operation of the boiler depends largely on the quality of the water used. This water is almost always river water, which contains dissolved minerals and salts. These salts precipitate, forming sludge in the tubes and causing scaling.

Main Electrical Equipment

The main electrical equipment is formed by:

• The alternator
• Transformers
• The switchyard (distribution park)