Waste Heat Evaporator Excess Water

I'm not an expert on boilers, but I think your idea of only sending the overflow water to the boiler is a safer bet.The way I see it is if you send the entire flow of water through the boiler you will overtax the boiler because the flowing water will never sit in the tank long enough to become sufficiently hot as to give the boiler a chance to rest.

Maybe I'm looking at it wrong,but that's my take on it.

Consider adding a steam accumulator.

http://www.spiraxsarco.com/resources/steam-engineering-tutorials/the-boiler-house/steam-accumulators.asp

good idea.

If you have another use for the hot water it should be ok to just send the overflow to the boiler feedwater tank assuming the condensate is pretty clean. If this water is condensate from softened water there may be no need to run it back through the softeners. I find it is allot cheaper to re use boiler condensate to help feed the boiler than to soften fresh water. I am not sure how big your boiler is and if has the capacity to heat the water in the tank as well as supply all your other steam needs. This should be very easily determined by doing some calculations. On thing I might add is that anytime I have tried to use a steam sparger to inject steam to heat water in a tank I have had problems and IMO a heat exchanger would be more officiant to heat the water.

pipewelder, we do use condensate from our driers in the Boiler, but still have to soften the makeup water for the Boiler. So we thought we may as well use the excess water in the Boiler as it already warm.

I have been told that direct steam injection is more efficient than heat exchagers because you are basically using all the latent and sensible heat from the steam. There is no energy loss from piping the steam condensate back to the Boiler feed water tank????

A few years ago we had a new RO water treatment system installed for all of our boiler water treatment needs. We also installed a new DA tank and heater set on a large waste fuel boiler as a separate project. After everything was done the engineer over the DA tank project figured out the new RO treated water was way to cold for the new DA system so it was left to me to design and install a steam sparger to heat the water until a heat exchanger could be designed and installed. I did this and installed a steam sparger into the new 250,000 gallon RO water storage tank, We had a ton of problems keeping the sparger working properly and I finally redesigned a sparger in a pipe set up out side of the tank to run the cold water through to preheat it. I used 2 fisher control valve and a couple of thermo couples to mange set set up and it worked pretty well and got us through a couple of months till the other equipment could be installed. The main problem we had was the intense noise that thing put out, it was a really loud high pitched whine that you could hear very well just about anywhere including my house 5 miles away. We do use steam spargers in a couple tile chests and a tall oil reaction tank and I always have to re work the tile each year from where they have damaged it by either ripping loose at anchor points or by beating up the tile/grout when they get loose and start to jump around. Also I bought a type of in line water heater that injected raw 150 lb. steam into a wash up water line to heat it. I tried and tried to adjust this thing to where it would do the job it was supposed to but it either made hot water and hammered like hell or didn't hammer and of course not make hot water. After about a year we bought a regular tube and shell heat exchanger that is still in use today. I guess it is just me but I have always hated injecting raw steam into colder water and really not had much luck with it.

We have no problem with our sparges. We have four, with many holes in the pipe. They are about 1.5 m long. It is noisy but the noise isn't to bad.