Question of the Day: Neutralizing Amine Feed Points

Where is the best location to feed neutralizing amines to a boiler system? 

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Taxonomy

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

5 Answers

1. Great answers are already posted by experts. 
   Storage section of the Deaerator. 

   At some customer's place, there was already a set up to dose it in the Make up line, which in fact was vaporizing more amine with vent. I informed customer but they dont want to change the existing set up. No worries my companies was paid for stripped amines also.
   
    

2. Actually, an even bigger factor in dosing neutralizing amine than the injection location in the system, is what percentage of boiler feed water / steam rate is returned as condensate?

   If under 90% then you have a poor system design or are using steam in direct injection in large amounts somewhere in process.  This requires a re-evaluation at this point.

3. For most neutralizing amines used in an industrial boiler system, the distribution ratio of amine in the steam versus the liquid is near negligible (there are some exceptions) so that injection into the Deaerator storage section is possible and preferred since the pH boost will enhance the efficiency of the oxygen scavenger.  Care must be taken to separate the feed from catalyzed sulfite since the close proximity pH spike will render the catalyst ineffective.  

4. We inject to the low pressure side of the boiler feed pump on the condensate header.  Not much really is lost due to relatively low water temperature at this location.

5. Since a lot of it can be lost in the venting system, it is probably better to add them after the boiler, on the high pressure side. However, this requires high pressure systems to inject it.