pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
(OP)
I can calculate the required amount of H2SO4 required to react with the ammonia (in a verticle packed tower scrubber). But I also need to know what "optimal" pH to operate at and also calculate my H2SO4 consumption to reach that point.
Thanks for the help.
Thanks for the help.





RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
ammonia is easliy scrubbed, even in a venturi-type scrubber
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
The chances are that you will need an acidic pH, so a PVC scrubber will probably be the best choice.
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
The diameter of the scrubber is calculated from air velocity (about 1.5 to 2 m/s).
The packing height depends on ammonia concentration in and ammonia concentration out (2 to 4 m heigh).
The liquid flow rate is about 12 to 20 m3/m2/h.
The pH is 2 to 4.
Be carefuul : with high ammonia concentration you can have serious heating due to heat of reaction.
H2SO4 consumtion is one mole H2SO4 per ole NH3.
The salt producted Ammonium sulfate
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
The diameter of the scrubber is calculated from air velocity (about 1.5 to 2 m/s).
The packing height depends on ammonia concentration in and ammonia concentration out (2 to 4 m heigh).
The liquid flow rate is about 12 to 20 m3/m2/h.
The pH is 2 to 4.
Be carefuul : with high ammonia concentration you can have serious heating due to heat of reaction.
H2SO4 consumtion is one mole H2SO4 per ole NH3.
The salt producted Ammonium sulfate
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
The scrubber is an existing FRP scrubber from a previous acid scrubbing application. NH3 scrubbing is much easier than acid scrubing so the scrubber size should not be an issue (per vendor). Main challenge is balancing water consumption versus H2SO4 consumption to keep pH of wastewater above 2.5 going down the drain. Thus my question for optimal pH. I understand that higher pH's require more water makeup (less acid) and a bigger drain load, while lower pH's conserve water. Mainly what I am hearing is can run anywhere between pH=2 to 5 and have no problem scrubbing 99%+ NH3.
Data:
15000 scfm with 3 lbs/day NH3 loading
500 gpm scrubbing solution circulation rate
8ft tower dia x 10ft packed section, Jaeger 3.5"Tripak
It appears from the 1:1 NH3 to H2SO4 value that I will only consume about 2 gal/day of 96% sulfuric (at any pH). So qualitatively speaking I believe I can run at pH close to 5 with no problems.
Make sense?
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
I am curious about your 1 mole H2SO4 to 1 mole NH3.
I was using the following chemical reaction equation:
2NH3 + H2SO4 = (NH4)2SO4
Is this not the correct equation to use?
Thanks,
AUSLK
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
By the way, ammonium sulphate is used as a rice field fertilizer, and as a supplier of nitrogen in fermentation processes.
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
Yes that is what I mean, and apparently not toxic (at least at the concentrations they are using).
Do you agree with the 1:2 ratio of sulfuric acid to ammonia?
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
www.revextechnologies.com
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
RE: pH for removal of NH3 from exhaust with dilute H2SO4 Scrubbing?
At higher temperatures, the vapour pressure of the contaminant overcomes its solubility. Remember, at equilibrium the reaction can go both ways.
The reaction you describe at ambient would tend to go to completion forming ammonium sulphate and NOT the bisulphate.
profaic