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Do You Have Rouging Problems?

By Nissan Cohen , April 10, 2016

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Recently rouging of two process vessels at a blood fractionation facility shut down production. 

The tanks of concern were derouged and passivated just 10 days before the rouge was observed on product contact surfaces prompting great concern.

The tanks are configured with baffles and stirrers connected to a main shaft.  “Staining” was noticed by the operators on several of these product contact surfaces.Each of the tanks was cleaned via a validated Clean In Place cycle. Following a visual inspection of the tank surface, agitator, baffles, and spray modules, a wipe test was conducted to see if there was any non-adherent rouge usually seen as a particulate on any surface or structure.

There are two classifications of rouge in 0-100°C water

Class1: This is form of rouge is non-adherent and a particulate. It is migratory from another source. Does not affect nor interact with the metallic surface and can easily be removed with wipes.

Class 2:  This form of rouge is interactive with metal causing pitting, corrosion, and a colored patina (orange, red, golden).  Can only be removed by chemical acids.  Wiping is not effective.  Forms a ferric oxide compound of hematite at temperatures between 0-100°C.

TANK

VISUAL APPEARANCE

TANK SURFACE

BAFFLES WIPE TEST

AGITATOR WIPE TEST

COMMENTS

1

SLIGHT PATINA

Numerous scratches and gouges

SLIGHT GOLDEN PATINA

NEGATIVE

NEGATIVE

Patina is 6-8” below Spray ball has non-metallic particulates

2

NO PATINA

NO PATINA

POSITIVE

POSITIVE

Spray balls likely not cleaning uppers

 

Tank 1 was designated as Class 2 rouge as it met all the criteria for that classification. The Spray ball was separated from Spray assembly and inspected.  Small non-metallic particulates were found inside the spray ball. Speculation was the particulates were of gasketing material from the CIP skid.  Particulates are undetermined, at this time, and further analysis night be needed to ascertain the material content.

Tank 2 was visually inspected for surface rouge and was found to be without rouge patina.  Wipe was performed with negative results.

The baffles and agitator had a fine reddish particulate rouge.  Wipes were used to single wipe the baffles and agitator. The test wipes tested positive and showed deposition of rouge particulates which were non-adherent to the surface.  This rouge was designated as Class 1.

Recommendations

  • Adjust spray balls to accommodate complete coverage rinse of the tank.
  • Check spray balls for foreign material.
  • Add filtration on the CIP skid to prevent foreign material getting to the spray ball.
  • Change pumps to something other than 316L, if possible. Alternative alloys and materials to be considered include AL6XN, Hastelloy, and PVDF impellers.
  • Check the CIP skid for rouging corrosion in pump impellers and piping
  • Mechanically polish tanks to 15 RA, clean and then passivate. This may inhibit rouge development but will allow Electropolishing (EP) to 25 RA.
  • Write SOPs based on a frequency for derouging and passivation for every three months as a minimum, for inspection guidelines, and identification of rouge classifications.

Results

Our personnelwere able to diagnose a problem quickly, assess the need for a plan to get the facility operational, provide expertise and knowledge to help client develop methods and return the facility to operation rapidly.

There’s always more to learn. And in our business, knowledge is power. That’s why Commissioning Agents, Inc. is committed to providing the objective, timely industry advice we can all benefit from. 

How to Understand ASTM E2500

 

 

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