Hey i need some help in calculating the thermal efficiency of steam turbine

[Amr Ali 33]

guys i just wanted to know the formula by which i can calculate the thermal efficiency of a pass out steam turbine( a steam turbine with an extraction for process ) I've attached a simple diagram explaining my problem can anyone please help !

 

[SteamKing]

You'll need more information than what is shown on the diagram, specifically the mass flow rates into the turbine and out the exhaust and extraction line, and you'll need to know the turbine work output. The exhaust conditions of 13" Hg are also a little ill-defined. Calculating the thermal efficiency of this machine is what a First Law type of analysis gives you.

 

[Amr Ali 33]

thanks , I've adjusted the diagram and added the data u requested i hope it's ok now , i would like to say that this is a very old power plant and that's what i could get out of it so please simplify the problem as much as the first law tolerates

 

[SteamKing]

thanks , I've adjusted the diagram and added the data u requested i hope it's ok now , i would like to say that this is a very old power plant and that's what i could get out of it so please simplify the problem as much as the first law tolerates

From this point, it's a bit of a slog with a calculator.

The thermal efficiency of the turbine = 1 - Work output / {Q(in) - [Q(out) + Q(ext)]}

You'll have to get some steam tables and look up the enthalpies of the steam at the inlet, the extraction, and the exhaust to calculate the amount of heat flowing thru the system. The generator output is turned into a heat equivalent at he rate of 3412.14 BTU/kW-hr

 

[Amr Ali 33]

thank you