Thanks for your prompt responses.
To air lance the unit compressed air (approx. 40 psig) is introduced into a forced air line into the underdrain header, and it is fed to the tank as fast as the operator can open the valve, and it's allowed to bubble up through the bed.
We drain the water...
The regenerant method is co-current, with an air-lance of the unit before a backwash. What you describe is what happened to all 4 anion tanks soon after they were installed. This motivated the plant to implement air-lancing (injecting the unit with air from the bottom of the tank for 20-30...
I work in a power plant as a design engineer, and the cation tanks in the demineralization plant here have run into a few problems: in normal use, the regeneration acid distribution lines in the tank (1"-d 314 SS) have been snapped off the header, and the header inside the tank (6" Schedule 40...
