# Performance Analysis of Power Plant Condensers - PowerPoint PPT Presentation

1 / 17

Performance Analysis of Power Plant Condensers . P M V Subbarao Professor Mechanical Engineering Department I I T Delhi. A Device Which makes Power Plant A True Cycle.. A Device Which set the limit on minimum cycle pressure….. . T-S Diagram : Rankine Cycle with FWHs.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Performance Analysis of Power Plant Condensers

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

## Performance Analysis of Power Plant Condensers

P M V Subbarao

Professor

Mechanical Engineering Department

I I T Delhi

A Device Which makes Power Plant A True Cycle..

A Device Which set the limit on minimum cycle pressure…..

### Thermal Processes Occurring in Condensers

• The condenser never receives pure seam from the turbine.

• A mixture of steam and non-condensable gases (Air-steam mixture) enters the condenser.

• The ratio of the quantity of gas that enters the condenser to the quantity of steam is called the relative air content.

• The value of e, depends on type, capacity, load and design dimensions of the condenser plant.

### Variation of Steam-air Mixture Parameters

Using Dalon’s Law:

Gas laws:

Volumes and temperatures are same.

• At the entry to condenser the relative content of air is very low and partial pressure of steam is almost equal to condenser pressure.

• As air-steam mixture moves in the condenser, steam is condensed and the relative content of air increases.

• Accordingly, the partial pressure of steam drops down.

• The total pressure in the bottom portion of condenser is lower than that of the top portion.

• The pressure drop from inlet to exit of condenser is called steam exhaust resistance of a condenser.

• The partial pressure of air at the bottom of the condenser cannot be neglected.

The temperature of steam is a function of condenser pressure.

As the air-steam mixture moves through the condenser and the steam is condensed, its temperature decreases owing to decreasing partial pressure of saturated steam.

This is due to increase in relative content of air in the mixture.

The pressure also decreases due to resistance to flow of steam.

The zone of intensive condensation.

The zone of cooling of air-steam mixture.

Tcw,out

Tcw,in

### Variation of Steam Partial Pressure & Saturation Temperature

Saturation Temperature, 0C

Steam Partial Pressure, kPa

exit

Inlet

### Condenser with Air Removal Pump : A practicable Concept

Combined Condensation & Air Pumping Action:

Air Pumping Action Vs Condensing Action !!!

Air pump controlling the back pressure

Condenser controlling the back pressure

Air pump controlling the back pressure

Condenser controlling the back pressure

### Effect of Air Leakage on Condenser Pressure

Inlet Condenser Pressure, mm of Hg

10

30

40

50

20

Cooling water Inlet Temperature

### Power Loss Due to Excess Back Pressure

What is Techno-economically Viable value of TTD ?

### Condensate Depression

• The temperature of condensate is always a few degrees lower than the coincident condensing steam temperature.

• Subcooling of condensate is undesirable on two accouts:

• It lowers the thermodynamic efficiency of the power cycle.

• It enhances the propensity of the condensate to reabsorb non-condensibles.