Steam generator calculation
Steam generator calculation
(OP)
Hi,
I am trying to see if its possible to build a steam generator using waste heat from my furnace, via a heat exchanger which turns basically turns water into steam. Basically, I need help with calculations. Here are some of the parameters:
1) Steam required = 30 kg/hr
2) Flue gas temperature = 800 degrees
3) Flue gas flow rate = 118 m3/hr
4) Pressure = normal atmospheric pressure
5) Water temperature = 25 degrees celcius
Is it possible with the above parameters to generate the required 30kg of steam per hour? And if yes, how much water need to be added per hour?
Hope anyone can help and thx!
I am trying to see if its possible to build a steam generator using waste heat from my furnace, via a heat exchanger which turns basically turns water into steam. Basically, I need help with calculations. Here are some of the parameters:
1) Steam required = 30 kg/hr
2) Flue gas temperature = 800 degrees
3) Flue gas flow rate = 118 m3/hr
4) Pressure = normal atmospheric pressure
5) Water temperature = 25 degrees celcius
Is it possible with the above parameters to generate the required 30kg of steam per hour? And if yes, how much water need to be added per hour?
Hope anyone can help and thx!





RE: Steam generator calculation
The heat content of the flue gas being about 270 kcal/normal m3, depending on the % excess air.
If the 118 m3/h flue gas rate is measured at 800oC, meaning about 30 normal m3/h, "normal" taken at 0oC and 1 atm abs, the apparent answer is no, you cannot.
RE: Steam generator calculation
RE: Steam generator calculation
The minimum theoretical heat required to convert 25oC water into steam, barring inefficiencies (losses), is about 620 kcal/kg water, assuming a small pressure above atmospheric to enable using the steam elsewhere.
Now, also assuming an excellent counter-current heat transfer (with finned tubes), and a good draft, the gases would cool down to, say, 150oC (no acid dew point envisaged?). At this temperature the gases' heat content is about 50 kcal/Nm3.
The available heat would then be: 30×(270-50) ≈ 6600 kcal/h.
The maximum theoretical amount of steam would then be: 6600÷620 ≈ 10.6 kg/h.
RE: Steam generator calculation
RE: Steam generator calculation
When speaking of savings, don't forget to include capex and opex, which, in small installations, seem to override the economies of energy. Good luck.