Steam condenser

By :- lowell harbert

Steam condensor Key points :-*Latent heat does not change the temperature.*Sensible heat changes the temprature of the System. sensible heatWater saturated liq. specific pressure

• latent heat Satu. Liq . Satu. vapour specific pressure

heatSatu. Vapour super heated steam

Steam condenser

Condenser

Power plant

• At every pressure there corresponds a temperature at which any fluid starts boiling is known as fluid`s boiling point.

• From steam table:- * pressure * satu. Temp 1 bar 100 c 0.5 bar 81.3 c 0.1 bar 45.8 c 0.05 bar 32.9 c 0.01 bar 7 c

Q . Why condenser is needed in steam turbine power plant?

Boiler turbine

feed pump condenser

Steam turbine power plant

What happen when there is no condenser?

Ans. If there is no condensor then steam will exhaust at atmospheric pressure .It means we can achieve 100c temperature at exhaust or during heat rejection.

* Any thermodynamic cycle can have maximum Efficiency only when there is high temperature

during heat addition and very low temprature during heat rejection.

*For achieving very low temperature at exhaust

*We introduced condensor.

*There is a vacuum which is maintained in the steamCondensor by vacuum pump .

*Steam expands to very low sub atmospheric pressure i.e. (0.1 - 0.04 bar).

*After expansion we get very low temprature correspond to condensor pressure or back pressure or exhaust pressure.

*It should be noted that after expansion dryness fraction should not be less than 85%.

*Ultimately we can say that condensor provide very low atmospheric pressure at exhaust of turbine.

*Now question arises up to what level we can drop the pressure of condensor or what are the restrictions ?

*Again answer lies in thermodynamical aspect *It is totally depends upon the temprature o

cooling water which is introducing in Condenser to condense the steam.*Suppose the pressure in condensor is

maintained at (0.01bar) it means we can only achieve 7c after expansion , but we introducing cooling water of 27c from atmosphere to

Condense the steam ,then it will be a reverse heat transfer from cooling water to exhaust steam.

7c steam

Cooling water at 27c Hot water out

In Out

Que. What happen when super heated fluid is passed through a condenser?

Ans. Firstly its temprature is droped down ,then it`s phase changes. *Application of condenser in air refrigeration

system:-

Consider air is at 1 bar pressure having boiling point 4c, But it is present in atmosphere of 32c it means it is in super heated condition.

Now if air is compressed isentropically up to 10 bar then it`s temperature will reached to 110c , then if it is passed through condensor then it`s pressure will not drop down but it`s temprature will drop down to 35c , and then it is expand in turbine (expander) then we

can achieve temprature around (-5 to -6 c ) .This is the principle of air refrigeration system.And it is used in aeroplanes. it is very low cost

process.