Concentrating HCl

[btgriff]

I have a waste stream that is ~2.5-3% HCl. It's a clean stream and I am trying to find a home for it other than our wastewater treatment. What's the best process for concentrating this stream to ~20-35%?

Thanks.

 

[EGT01]

I applaud your attempt to try and minimize your waste but I suspect it will not be practical to try and "concentrate" your HCl stream by removal of water. You will likely do better by trying to increase the HCl concentration by absorption of anhydrous HCl. For concentrations in the 35% range, a falling film type absorber is typically used. For the lower concentrations, a packed bed absorber can be used.

You don't say what you intend to do with the higher concentration of muriactic acid, that could ultimately have a bearing on how you achieve the higher concentration and its resulting quality from an impurities standpoint.

The past few years, I've worked indirectly with an industry that produces HCl as a byproduct from a reaction step for their main product. It seems to be a continuous challenge for them to find sufficient outlet for the HCl and they get better price for the anhydrous than the muriactic. So if you are looking to market the muriactic, good luck.

Depending on the quantity and quality of your stream, you might do better by trying to find a use for the waste stream within your process. If nothing else, is it possible to use it has a way to adjust the pH of other waste streams that have to be processed?