Nitrogen vs steam blanket on top of hot water thermal storage tank
Nitrogen vs steam blanket on top of hot water thermal storage tank
(OP)
Hi...
I'm designing a 35 MW hot water stratified thermal storage tank (at 95°C) for an existing district heating system; and there is concern about system corrosion protection. The water will be treated with corrosion inhibitor and other chemicals, but I'm considering to have a blanket at the top of the tank to protect against oxygen dissolving into the water (oxidization?). Do you know of any issue with Nitrogen blanket given the type of application? How do I calculate the amount and pipe size needed? Any design consideration I need to be aware of?
Thanks in advance
I'm designing a 35 MW hot water stratified thermal storage tank (at 95°C) for an existing district heating system; and there is concern about system corrosion protection. The water will be treated with corrosion inhibitor and other chemicals, but I'm considering to have a blanket at the top of the tank to protect against oxygen dissolving into the water (oxidization?). Do you know of any issue with Nitrogen blanket given the type of application? How do I calculate the amount and pipe size needed? Any design consideration I need to be aware of?
Thanks in advance





RE: Nitrogen vs steam blanket on top of hot water thermal storage tank
RE: Nitrogen vs steam blanket on top of hot water thermal storage tank
RE: Nitrogen vs steam blanket on top of hot water thermal storage tank
For line size, assume a low flow velocity (minimum friction). Maybe 1-2 fps or less in the nitrogen line. If your pressure control valve (regulator) is quite close (less than 8-10 meters?), you can live with more friction loss. If it is very distant (50 or more meters?), you will want to have more diameter so that the pipe acts as a reservoir, and you have almost no friction loss.
RE: Nitrogen vs steam blanket on top of hot water thermal storage tank
The systems were normally designed to maintain the tank at +0.5" WC.
Make sure you have a vacuum relief valve in the system if you are going to try and design you own system. If you don't include one and you get the outflow rate greater than the inflow rate you end up with a very nicely collapsed tank.
One of the biggest demands for the inerting gas will be caused by the diurnal temperature changes, assuming you are able to balance the in and out flow.