Using sulphuric acid for regenerating resin 1

[pt1000]

A customer of mine has asked me a question about the production of DM water, a section where I dont know much of.
They regenerate the resin with hydrochloric acid. The question is if they can do the same with sulphuric acid. They are allready using sulphuric acid in their main processes and it would probably skip a wastestream

 

[jmj5152]

pt1000
Should be no problem. A few issues you would have to be careful about. If the feedwater has hardness, you will need to do a stepwise regeneration (starting with low sulfuric, then raising concentration) to avoid calcium sulfate precipitation on the resin. Also, sulfuric acid will tend to dehydrate and shrink the resin during regeneration, therefore, depending on the concentration used, the rinse cycle may get longer, so the resin can rehydrate. This shrink/swell cycle will also cause much more resin breakage. If they can continue with HCl, they should, it is much more efficient, but sulfuric is widely used for ion exchange resin regeneration.

 

[cub3bead]

Many IX systems are regnerated with H2SO4. Your IX run lengths will be shorted significantly because the cation resin isn't regenerated as effectively. I would be cautious about using waste acid to regenerate with.

 

[bimr]

Most IX systems use sulfuric acid rather than hydrochloric acid for regeneration because sulfuric acid is cheaper. Your client should go back to the equipment supplier and have them reconfigure the system so that it would work with sulfuric acid. jmj5152 has also made some good comments.

 

[pt1000]

Thnx all for your advice, I will pass the word!

 

[BenThayer]

we used ion exchange to make de-ionized (DI) water for our higher pressure steam (~900 psig). we used H2SO4 for the cation and NaOH for the anion. This was then combined into a neut. pit and the pH adjusted as necessary before going out the sewer system.

we also used salt to make de-mineralized (DM) water for a lower pressure steam system (~600 psig). this was to exchange the Ca++ for Na+

the H2SO4 sounds like it should be a good deal. just make sure the resin is compatible and recalculate the volumes required to compensate for strength of acid. HCl is typically 34-36% and has a single H+ vs. the ~98% H2SO4 and two H+'s.