H2 converter Catalyst

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  • #101997
    Mark Brouwer
    Keymaster
      • Expert
      #101995
      redagalih
      Participant
        • Participant
        quote mark.brouwer post_id=3867 time=1362084516 user_id=2:

        Did you check the position of the MP scrubber off gases in the explosion diagram with 3% H2 ?

        I have read a Saipem operating manual, which described that at an upset condition of 0.8 vol% H2 instead of 0.25 vol% O2 in the CO2, one enters already the explosion area in the MP scrubber and where Saipem advised to add methane to the MP scrubber to move outside the explosion area again.

        Sorry, I just find this topic and have a related question..
        Anyone have explosion diagram (H2, O2) for Urea plant? We had some trouble about Pt catalyst performance.. H2 outlet reactor still 0.3% (inlet 0.5%). Is it safe to keep this condition for months? our O2 outlet reactor is 0.7% (inlet 0.8%).

        Thank you

        #97430
        sadanand-i-m
        Participant
          • Participant

          Dear Sir,

          Nornally we get around 0.65 % hydrogen in CO2 coming from ammonia plant. whenever ammonia plant oeprating at low plant loads or any upsets, the H2 content would go upto 0.85%. THumb rule is 1% hydrogen gives 50 deg C rise across catalyst bed.

          #97429
          Mark Brouwer
          Keymaster
            • Expert

            Did you check the position of the MP scrubber off gases in the explosion diagram with 3% H2 ?

            I have read a Saipem operating manual, which described that at an upset condition of 0.8 vol% H2 instead of 0.25 vol% O2 in the CO2, one enters already the explosion area in the MP scrubber and where Saipem advised to add methane to the MP scrubber to move outside the explosion area again.

            #97427
            Mark Brouwer
            Keymaster
              • Expert

              Its range is considered to be 3% max experienced as safe. Above this we do not have experience in snam plant.

              #97424
              Mark Brouwer
              Keymaster
                • Expert

                In a Saipem plant with a hydrogen converter, in the MP scrubber one enters into the explosion area when hydrogen content becomes too large.

                #97421
                Muhammad Aslam
                Participant
                  • Participant

                  Dear All,
                  I have one question which is relevant to this topic somewhat. We are experiencing leakage in one of our benfield reboiler which is causing high H2 in CO2 stream (1.4% H2 in CO2). If anyone has such experience and particularly what is the maximum limit of H2 in CO2 for urea plant without H2 converter?

                  #97419
                  Mark Brouwer
                  Keymaster
                    • Expert

                    Dear Norozi,

                    What is your catalyst design fusion temp.? On the other hand of Mr. Farooq by the operator mind the O2 contents of H2 reactor are kept constant and plant will not be stopped due to H2 slippage but if not stop then air to d/s will become deficient.

                    #97417
                    norozi1972
                    Participant
                      • Expert

                      Dear friend
                      besides of our friends discussion ,One of the high hydrogen content’s effect can be increasing the converter temperature rapidly and finally can fuse the Catalyst.
                      with best regard
                      khpc._ Iran
                      norozi

                      #97412
                      Mohammad Farooq
                      Participant
                        • Expert

                        dear kashif,

                        Besides mohammadian recommendation , i would like to elaborate as,

                        normally we are experiencing less than 1% hydrogen in the co2 available for compression purpose as design temp of converter is very important .
                        second point is amount of air available to the hydrogen converter and capacity of air flow control valve/air limitation from air compressor . The available quantity of oxygen will react with hydrogen and will increase the temp . however if due to some problem at ammonia hydrogen comes in excessive quantity say more than 2-3%, then this hydrogen will not react due to oxygen limitation (air flow) and will escape to synthesis beside max temp at converter which of course is undesired.

                        regards

                        #97411
                        Mark Brouwer
                        Keymaster
                          • Expert

                          Thanks Muhammadian .Any other opinion.

                          #97406
                          Mark Brouwer
                          Keymaster
                            • Expert

                            Dear Naseem,
                            The limitation for H2 removal reactor mainly depends on the reactor metal design temperature as mostly it will be designed for 300 degree C, it is important to protect the reactor itself(keep a temperature margin of 30 to 40 degree C), but if the design temperature of the reactor is higher than 300 degree C then it would be possible to add air and control the O2% at desired value in order to be in safe side from corrosion point view and far away from explosion mixture conditions.

                            #92815
                            Mark Brouwer
                            Keymaster
                              • Expert

                              Dear Gentlemen,

                              Can any one define the max. limit of H2 in CO2 gas .is its tripping every where is on dischrge temperature.

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