What is the best method to neutralize a tank heel (~100 gallons) of Sulfuric Acid? We have a small heel (~200 gallons) of 98% sulfuric acid in a horizontal tank with no bottom connection that we want to remove by first neutralizing, and then pumping out conventionally with a hose and portable pump. The tank is about 9 ft in diameter and about 30 ft long so there is plenty of vapor space. I was thinking that if we slowly pumped in caustic, monitoring tank temperature by feel on the outside of the tank, we could slowly neutralize it. Obviously, it will generate heat and warm up the tank and contents -- producing soluble sodium sulfate and water. We can open a nozzle while we add the caustic. My only question is, if we pump in say 1 gpm, how violent would we expect the reaction to be? Is this safe?
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Dennis Hendershot Forum Moderator 17 Posts
Re: What is the best method to neutralize a tank heel of Sulfuric Acid?10 September 2012 at 12:23pmWithout much in the way of details, I don't really know whether or not this is safe. I think it needs a thorough hazard analysis with participation by a chemist who understands how much heat is generated, and engineers who know something about the equipment capabilities. You would have to do some temperature rise calculations, and then also worry about the lack of mixing and the potential for local heating to a temperature higher than you would predict from something that was completely mixed. We had a splashing incident when diluting caustic in water where the calculated maximum temperature was well below the boiling point. However, the mixing was poor and the local temperature where the caustic and water contacted each other was high enough to cause boiling and some caustic erupted from the tank opening (it was a small tank) and splashed somebody.