Question of the Day: Common Drain

Media

Taxonomy

• Water Softener
• Cooling Boiler & Wastewater
• Industrial Water Treatment
• Industrial Water Treatment
• Industrial Water Managment

5 Answers

1. Big problem.  I have seen this too often.  A big scale build up at the point where the flows mix together.

   Wow, don't they teach qualitative analysis in chemistry classes anymore?  High alkalinity from the boiler will precipitate the hardness down for the bottom blowdown valve to remove.  Duh!   High alkalinity from the boiler will precipitate the carbonates, hardness and a lot of other things.    Look up lime soda softeners and learn how they work.   Learn about precipitation and why it happens.  Most of all, get off the net and quit asking questions of people who don't know.  Go get a chemistry text book and read it and forget the computer discussions.  This was written about over 100 years ago.  Good grief kids. 

2. I agree with David Barter and I add that the boiler blow down water has relatively high pressure, which could block softener's and dealkaliser reject to flow freely, especially if boiler blow down is continuous. In such circumstances the regeneration will fail. 

3. The issue here really is one of Hardness.  The hardness from the regen will precipitate if either the temperature is increased such as from blowdown or the pH or carbonate concentrations are increased .  

   The Softener could be combined with the blowdown only if the blowdown was cooled to room temp prior to mixing with the high hardness water form the softener.  this may be done with softened quenching water or exchangers for capture of the heat.

   As for the Dealk it depends which type of dealk you are using.  Weak Acid Cation, or Split stream would not cause issues with a softener, however if you are using a Cl Anion and are regenerating with salt and caustic, you could likely have some issues if both systems were to regenerate at the same time. You would have high hardness and high pH/Alkalinity which is a recipe for scale formation and potentially big issues.

   another factor to consider would be other flows in the same drain that could be a diluting factor.

    

   Hope this helps

4. Good question. My immediate reaction was it would scale but how are you running your dealkalizer is more the determinant?

5. This sounds like a recipe for a plugged pipe.