[rnaks]

Can anybody please tell me whether there should be any scrubber placed on the vent line to capture any gases that are coming out of 98% Sulfuric Acid Carbon Steel Storage Tanks. The tank is exposed to ambient conditions and the outside temperature can be as high as 105 F in summer days. The boiling point of 98% sulfuric acid is about 600 F. The gases that would release when concentrated sulfuric acid reacts with metal of storage tank is H2 gas, and is released when acid is first filled in the tank. I was told that as part of the permit the sulfuric acid tanks may require a scrubber to prevent sulfuric acid vapors from releasing to atmosphere. The PEL for sulfuric acid is 1 mg/m3. Under the above circumstances, do we really need a scrubber ? and will there be any additional gases that will be released ? I understand some of these tanks have a dessiccant dryer to prevent any ingress of moisture into the tank.

Please answer. Thank you in advance.

[cpncoop]

Sulfuric acid has a pretty insignificant vapor pressure, so you theoretically could get away without a scrubber.  Nevertheless, I'd put one on the tank anyways just in case.

[mbeychok]

The vapor pressure of sulfuric acid at atmospheric temperatures, even at 100 deg F (38 deg C), is so low that a scrubber is not needed. Just make sure that the vent outlet is located at a point that will not endanger workers should liquid ever flow out of the vent.