Problem pumping 98-99% Nitric Acid 1

[pumpking]

We have recently been asked to recommend a pump for roadtanker unloading 98-99% Nitric Acid to a bulk storage tank, and seeked assistance from one of my French colleagues who has vast experience in such applications - only problem is i cant understand French so dont fully understand the problems associated with pumping this high concentration Nitric.

He was saying that one of the key concerns was the NPSHa in the system as the Nitric pull out into gases ? We are handling the product with PFA lined pumps successfully, but it is the theory behind the system implications that i do not understand 100%

Can anyone assist in this please ??

 

[BigInch]

Best excuse I've ever heard of to learn French.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[kenvlach]

Nitric acid has a fairly high vapor pressure & boils at 83 ^oC.* It also contains up to ~4% dissolved NO₂ gas which comes out readily at atmospheric & reduced pressures, hence the name white fuming nitric acid (WFNA) for 98-100% nitric. So, presumably the NPSHa concern is with nitric acid vapor + NO₂ gas. Best to order WFNA with an NO₂ < 0.5%. Mfrs. remove NO₂ "using reduced pressure at room temperature (10-30 min at 200 mmHg or 27 kPa)."

http://www.answers.com/topic/nitric-acid

Maybe some useful information here: GUIDELINES FOR TRANSPORTING NITRIC ACID IN TANKS

http://www.efma.org/publications/NitricAcid/Index.asp

Note Annex 1: Physicochemical properties of nitric acid



*Boiling point reported in many MSDSs of 121-122 ^oC is for the 68% azeotrope with water.