One of the specialised services offered MPE Ltd is called derouging of Stainless Steel surfaces, found in processing components, spools, vessels, tubes, valves etc, used in the Pharmaceutical, Biotech and Medical industry.
The process is employed to remove a form of orangey / red surface contamination known as 'rouging'. This phenomena is a form of ferric oxide formation and is commonly found where elevated temperatures are involved, such as steam lines, etc.
The Process involved a two stage operation, described below:
1. The chemical cleaning process known as derouging, removes any free iron, surface contamination and staining, from the inner surfaces of the stainless steel process equipment.
This process requires the use of a mild chemical known as Willowchem 61. This specialised chemical is pumped through the process equipment lines with a varying calculated surface contact time, depending on the surface area and the level of rouging present on the surface.
After the derouging process the Willowchem 61 solution is thoroughly rinsed through until a neutral pH is achieved.
2. After ensuring that rerouging has taken place, the equipment will require a passivation process to ensure that the protective oxide layer was intact.
This process required a 5% - 10% Citric Acid solution to be pumped through the process equipment with a calculated contact time of liquid to metal surface.
After the passivation process the citric acid solution is again thoroughly rinsed until a neutral pH is achieved.
After these two processes are complete, our technician will use non-invasive passivation testing methods to determine the validity of the passivation process, on each piece of process equipment and the results recorded and compiled in a comprehensive report.
This operation can be either carried out at our factory or at your site location.
If you require any further information on the derouging process, please do not hesitate to contact us to discuss your requirements.
Above: Before and after de-rouging of stainless steel