JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV POWER PLANT INSTRUMENTATION Previous Question Paper (July/August - 2022 - R18)

A solar power plant, specifically a Solar Thermal Power Plant, converts solar radiation into thermal energy to drive a steam turbine for electricity generation. The process involves a solar collector field (parabolic troughs or heliostats) that concentrates sunlight onto a receiver containing a heat transfer fluid (HTF). This fluid is heated to high temperatures and circulated through a heat exchanger to generate steam. The steam then drives a turbine coupled to a generator.

Important parameters to be monitored include:

• Solar Collector Field: Solar insolation (W/m²), HTF inlet and outlet temperatures, and tracking system accuracy.
• Heat Exchanger/Steam Generator: Steam pressure, steam temperature, and HTF flow rate.
• Turbine-Generator Set: Turbine speed (RPM), steam flow rate, vibration levels, and electrical output (voltage, current, frequency).
• Cooling System: Condenser vacuum pressure and cooling water temperature.

The boiler process is the core of a thermal power plant where chemical energy from fuel is converted into thermal energy in steam. It involves three primary stages: combustion, heat transfer, and steam generation.

Key processes include:

• Combustion: Fuel (coal, oil, or gas) is burned in the furnace. Air is supplied via forced draft fans, and combustion gases are removed by induced draft fans.
• Heat Transfer: The flue gases pass through superheaters, reheaters, and economizers to maximize thermal efficiency.
• Steam Generation: Feedwater is pumped into the boiler drum, circulates through water walls where it absorbs heat to become saturated steam, and is then superheated to increase enthalpy before entering the turbine.

Example: In a pulverized coal boiler, coal is crushed into a fine powder and blown into the furnace with primary air to ensure rapid, complete combustion, which heats the water-filled tubes lining the furnace walls.