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Derouging with DIRUNEUTRA and DIRUPURE

Technical Information
Modern production procedures are increasingly forgoing the use of caustic, acidic or similarly hazardous substances for derouging and cleaning processes. Catalysts in the form of chelating agents can speed up reactions and often even allow an improved outcome through targeted reactions. Diruneutra procedures are based on two steps using different chemical formulations. The reagents are supplied in concentrated form and are diluted with purified water on site. The concentration of the ready-to-use solution can be adjusted by varying the amount of concentrate added according to the degree of rouge present. This controls cost and helps protect the environment. Our derouging and passivation solutions can be applied through immersion, flooding, and spraying procedures. This means that beside the known applications for cleaning pipe systems, even autoclaves , batch production and storage tanks, or even freeze-drying systems can be effortlessly cleaned.

The Diruneutra kits of derouging concentrate can be stored unopened for up to two years and are available in two kit sizes with the appropriate Diruneutra concentrate to mix up to 250 L or 1,000 L of derouging solution. The concentration can be increased up to four times the amount. Depending on the capacity of the equipment and the severity of rouge present, the concentration is mixed and added in the system to be treated using 75 to 85 °C De-ionized water. Should the equipment to be derouged use the spray method utilizing the CIP system, then it must be rendered inert with nitrogen to a residual oxygen content of less than 0.5 % prior to adding the derouging kit. Once the system is inert, the solution can be moved through the system using spray nozzles, circulation pumps or agitators. Only the system parts wetted by the solution will be cleaned. One started, the derouging process takes between 30 minutes and 4 hours depending upon temperature and severity of rouge present. Reactivity of the solution is monitored by periodically sampling for iron and activity. Once the exposure time is complete or the derouging solution is no longer active, a prescribed amount of Diruclean NS is added and mixed with the pH neutral solution. This step stops the reaction of the Diruneutra derouging product and after approximately 45 minutes of circulation, the pH neutral residual solution can be emptied into the in-house waste water system. The equipment surfaces and piping systems is then flushed for at least five minutes with either hot or cold running water. The subsequent bare metal stainless steel surface still requires a controlled renewal of the passive layer rich in chromium oxide.

In order to do this, the system is filled with cold, demineralized water (< 30 °C) and Hydrogen Peroxide concentrate is added in the prescribed amount. All the surfaces to be passivated must now be continually wetted with the solution for at least 45 minutes.

Once complete, the Hydrogen Peroxide oxidation solution is then also emptied into the waste water system and the system is flushed with running water for five minutes and a final conductivity test is performed. The procedure is finished once a difference between input and output conductivity of the rinse water is less than 1.0 µS/cm.

MSDS Sheets
msds_acds tabs_e.pdf
hydrogen peroxide msds.pdf

Substrate Compatibility
Customers are always concerned about compatibility of gaskets, seals, valve diaphragms, etc… in their system and whether the use of passivation chemicals will damage those components. We are sympathetic to those concerns and have performed compatibility tests on many of the materials used in pharmaceutical manufacturing systems. The information listed below in the attached PDF verifies that Diruneutra IS compatible with the most common elastomers and steel chemistry used today in sanitary process systems.

Please take a look at the information attached. If you do not see your material of concern listed, please contact us and we will be happy to verify compatibility.

Derouging and Passivation with Diruneutra, and Substrate compatibility