A condenser in a thermal power plant condenses steam combing out of

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Examoogle · Accepted Answer

Turbine

Explanation: In a Rankine cycle-based thermal power plant, the condenser is situated immediately after the steam turbine exhaust. It serves to convert low-pressure exhaust steam into liquid condensate, which is then pumped back to the boiler.

Working Principle: The turbine extracts work from high-pressure steam, causing a pressure and temperature drop. The exhaust enters the condenser where it loses latent heat to a cooling medium (usually water), causing a phase change to liquid. This process creates a vacuum at the turbine exhaust, increasing the turbine expansion ratio and overall plant efficiency.

Key Formulas: $W_{net} = W_{turbine} - W_{pump}$ — Net work output of the cycle; $\eta_{thermal} = \frac{W_{net}}{Q_{in}}$ — Thermal efficiency of the power plant

Key Points: Condensers operate at sub-atmospheric pressure to maximize enthalpy extraction.; Heat rejected in the condenser represents the largest energy loss in a thermal cycle.; The vacuum in the condenser is maintained by vacuum pumps or steam jet ejectors.

Advantages: Increases the total work output of the turbine by expanding steam to lower pressures.; Recovers high-quality treated feed water for the boiler.

Disadvantages: Requires a large supply of cooling water or massive cooling towers.; Susceptible to biofouling and corrosion in heat exchanger tubes.

Applications: Steam Power Plants (Coal/Nuclear/Gas); Marine steam propulsion systems

Additional Info: Boiler (Option A) produces steam; Super-heater (Option B) increases steam temperature; Economizer (Option C) preheats feedwater using flue gases.. A surface condenser is the most common type used in large utility-scale power plants.

Answer: D is correct — The condenser is connected to the turbine exhaust to condense the low-pressure exhaust steam back into water.

Exam Tip: Always remember that the condenser is the site of 'Heat Rejection' ($Q_{out}$) in the Rankine cycle, and its efficiency directly impacts the vacuum pressure and cycle efficiency.

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