For a new boiler installation, we are looking at keeping the FD and ID fans running in case of a power failure. This would be at low load, but high enough to keep a draft and prevent an explosion. Let's say 25% of full load, or 25% speed (these are VFD).
The question I have is how much power...
I think not only is the velocity important, but so is density. Recall that isokineticity is important for stack testing because of the density difference between the particulate and the gas. If there is not much difference, there is no need for isokinetic sampling. For example, you don't need to...
Superheaters can have anywhere from one up to (I've seen) five stages. Not each stage requires an attemperator. For example, a single stage will not have any attemperator, that would make no sense at all, for reasons given by crshears. The fact that there is necessarily a stage after the final...
You actually have more information than you need. There is no need for any steam data to calculate efficiency.
The best way to do it is the heat loss method (try googling). Basically, you figure out how much heat is being lost up the stack, based on the fuel analysis and excess air...
