1 reply to this topic

[Carlo717]

I have around 151m3/s of air that needs heating to 110degrees C. I thought heating this air with steam via a plate fin heat exchanger may be a good idea and need to calculate the requirements of the steam.

I used Q=mcpdt for the air and using a dt of 90C got my Q to be around12666Kw

For condensing air I was planning to use Q= MHc where Hc is the latent heat of vap... my issue is it seems the latent heat of steam decreases as pressure and temp go up and so providing steam at a higher temp actually means I need more... why is this and what have I done wrong?

Thanks.

[Art Montemayor]

Carlo:

From what little information (and no detailed calculations submitted) you have furnished us, you don't seem to be going off on the wrong direction. However, since you don't submit your detailed calculations in an orderly and logical manner, we also don't know your basis for the calculations, the inputs of the stream properties and conditions. You are confusing your own self and creating self-doubt because you are not employing basic engineering calculation methods and procedures.

Supply the Forum with detailed, concise calculations, a sketch, the basis for your calculations as well as all the stream properties and conditions and you will find that the support and assistance you receive will be quick, correct, and effiicent for your profitable learning,