pressure-temperature

[wwtp2014]

Dears

we have boilers produce steam with 7 bar and we use it for Dairy application we have PRV's to get 4 bar, 1 bar and 0.3 bar so please what is the Corresponding temperature for each pressure


Thank you

 

[LittleInch]

Steam tables

http://www.thermopedia.com/content/1150/

Note that P in the table appears to be absolute pressure, hence 1.3 bara = 108C, 2 bara = 120C and 5 bara = 153C all based on saturated steam

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[willard3]

Buy this, then you will have reference

http://www.amazon.com/Thermodynamic-Properties-Steam-Joseph-Keenan/dp/B0015P99NI

 

[stgrme]

Assuming a throttling process with no loss of heat, the temperature will fall as pressure is decreased, but the steam will become superheated as the pressure falls. You need to determine the enthalpy for saturated steam at the initial pressure (absolute) and then use that enthalpy to determine the temperature at each of the lower pressures.

For example, if 7 bar is a gauge pressure (barg), the absolute pressure will be approximately 8 bara. The enthalpy at 8 bara is approximately 661.2 kJ/kg. Using this enthalpy, the approximate temperature at each pressure is as follows:

5 bara (4 barg) ==> 160 deg-C

2 bara (1 barg) ==> 150 deg-C

1.3 bara (0.3 barg) ==> 147 deg-C

Best of luck!

 

[wwtp2014]

Thank you stgrme

please why we consider initial steam from the boiler as saturated steam and the steam after PRV's as superheated steam

Regards

 

[ione]

Steam at the PRV's outlet keeps approx the same enthalpy as at the valve's inlet. Being the steam pressure reduced, this may translate in a superheated steam or in a higher steam quality (depending on upstream conditions and amount of pressure reduction)

 

[stgrme]

Please pardon me. I assumed that the steam from your boiler was saturated since you did not give a temperature. However, the procedure for determining the temperature at each pressure is the same as I had indicated in my previous post. Determine the enthalpy of the steam at 8 bara and use this enthalpy along with each pressure to find the corresponding temperatures.

Please note that in my previous post, I incorrectly stated that the enthalpy of saturated steam at 8 bara was 661.2 kJ/kg. This enthalpy is actually for saturated liquid. The correct enthalpy for saturated steam is 2768.3 kJ/kg. Also note that the temperatures at each pressure I noted in my previous post are correct.

Best of luck!

 

[crshears]

please why we consider initial steam from the boiler as saturated steam

OP never stated steam from boiler was superheated, ergo others will ASSume only dry saturated steam is being delivered.

As LittleInch noted, providing more information yields better answers!

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]