Steam Calculation
Steam Calculation
(OP)
How do you calculate approximatly the energy (kWatts)required to generate 300kg/hr of steam. I have medium temp hot water at 138/115 deg C serving a humidifiers heat exchanger, and I need to know the kW and L/s of the hot water.???





RE: Steam Calculation
RE: Steam Calculation
RE: Steam Calculation
For 300 kg/hr you require 300x2310 kJ/hr or 693000 kJ/hr or 192.5 kW. As there are no water losses, your hot water flow rate should be 0.083L/s (add 1 to 2% for blowdown).
Not a good idea to go with electric boilers.
Regards,
RE: Steam Calculation
Try JS Humidifiers.
Friar Tuck of Sherwood
RE: Steam Calculation
Should the water flow rate in L/s be 2.0l/s since the delta T of the hot water serving the humidifier Heat exchanger is 23deg C.???, It's the Hot water flow rate im trying to calculate.
RE: Steam Calculation
693000 kJ/hr = m(kg/hr)x4.2 kJ/kg0Cx230C
So the mass flow rate of hot water will be 7173.91 kg/hr or 1.99 kg/hr (~1.99 Lit/sec). This calculation considers supply of 1000C feed water.
If your water temperature is 300C and you want to use a dT of 230C, then the hot water flowrate should be 8086 kg/hr or 2.25 L/s for steam at 1 atmosphere.
You have some important things to check.
1. Is overall heat transfer coefficient of the heat exchanger is sufficient to produce the steam quantity required?
2. Is it primarily designed for similar application? (steam formation near the pipe wall will reduce the overall heat transfer coefficient)
3. Dryness fraction of steam produced in the above manner will be low and subsequently the humidified air temperature will drop down. You have to provide reheating.
Regards,
RE: Steam Calculation
To produce 300 kg/h of humidity, by vaporizing water in your exchanger/humidifier (isothermally) at 25oC, with hot water cooled in a range of 23 oC, you'll need 300 kg/h*2442.5 kJ/kg=732750 kJ/h or 203.5 kJ/s.
A hot water drop from 138 to 115oC would mean a drop of about 98 kJ/kg which would result in 2.08 kg/s = 2.24 L/s of hot water.