Passivation Air Requirment in SAFUREX

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  • #98361
    Mark Brouwer
    Keymaster
      • Expert

      Fatima fertilizers in Pakistan is totally SAFUREX material based plant and after 1st TA found some corrosion effects in pool reactor inner surface and in HP stripper. so passivation air 0.3% vol. started and in next TA almost negligible corrosion effects are noticed.

      #98360
      mehdijafarpour
      Participant
        • Participant

        Hi everyone
        In SPC prill urea plant, only reactor & stripper / condenser package has been modified to safurex & from the time we have decreased passivation O2 to 0.45% from the original content of 0.6% for over 8 or 9 years & corrosion rate evaluated in 2 or 3 overhaul periods has been acceptable & therefore this decreased 0.45% of passivation oxygen is still continuing.
        Stamicarbon has published a paper about their first test of decreasing oxygen content in urea plant with safurex modified major equipments in cooperation with SPC several years ago which mentioned to their successful results of the test especially after precise inspection of the plant in the first overhaul 1.5 years after the point of decreasing passivation O2 content .
        I guess the article was presented in 2005 or 2006 Stamicarbon symposium in Canada.

        #98344
        Mark Brouwer
        Keymaster
          • Expert

          The plant designed for zero oxygen is the Terra del Fuega plant in Argentina, which is under evaluation to change the location to the US as shale gas makes the US more attractive.

          Please be aware one needs special eddy current techniques to be able to measure accurately the wall thickness of a super duplex tube. This technique has been under development and changed during the recent years leading possibly inaccurate results in older measurements. Only after pulling a tube one can know the real corrosion rate in time…

          #98342
          akbar-ali
          Participant
            • Participant

            One of our Urea Plant @ SAFCO, SAFUREX material was used and commissioned in 2006, but it was observed in TA 2012 that stripper tubes corrosion rate was acceptable but with high rate than the normal experienced.
            Due to this threat we are also supplying air for passivation and maintaining O2, 0.6% vol. as same as other urea plant using urea grade material.

            Any other plant having some better results of SAFUREX…???

            Thanks and Best Regards

            #98341
            norozi1972
            Participant
              • Expert

              Dear friend
              As Mr Naseem mentioned and I heard before, Sufurex is designed for zero oxygen but all equipment must be as sufurex material like control valves, instrument equipment, piping,….
              I think one urea plant is under construction with full sufurex material,any body have any data?
              With best regard
              Norozi

              #98340
              Mark Brouwer
              Keymaster
                • Expert

                SAFUREX material design is for zero % o2 but we faced corrosion ans using 0.3% O2 as passivation

                #92996
                akbar-ali
                Participant
                  • Participant

                  Dear Mark,

                  what is your understanding/knowledge about supplying of passivation air in synthesis loop pertaining to SAFUREX material.

                  One should use or not…????

                  If yes, how much Vol.% of O2 should maintained ????

                  Thanks and Best Regards

                Viewing 7 posts - 1 through 7 (of 7 total)
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