Prilling Tower Scraper Urea Deposit

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Viewing 9 posts - 1 through 9 (of 9 total)
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  • #106838
    Mark Brouwer
    Keymaster
      • Expert

      Find a coating solution enclosed

      #102152
      shahzaib
      Participant
        • Participant

        Hello,
        There are few possibilities due to which urea deposition at scrapper happening.
        1.low bucket rpm.
        2.wide opening of melt urea pump o/L valve.
        3.moisture in product
        4.passing of three way valve towards bucket while doing bucket cleaning.
        5.final temprature low.

        These are few prossibilities as per my experience.if you can share your bucket cleaning or current plant parameters with me hope so we will resolve this issue or conclude the problem…..

        Shahzaibawn@gmail.com

        #102140
        pbaboo
        Participant
          • Expert

          Wet cleaning should not be done in running plant, it will take more time for removing wet/slurry material. The liquid effluent load also increased. wet cleaning may be done in shut down.
          The hot condensate also more dangerous. Safety equipment (face shield ,apron, etc) may be used.

          Regards,

          #102139
          Muhammad Kashif Naseem
          Participant
            • Expert

            this liquid condensate use to clean scrapper will cause to wet the scrapper floor and will stick the material more on floor than the removal of scrapper which will make the scrapper probably more rigged to move. hence may damage the scrapper.

            What are u doing with wet floor after cleaning?

            #102138
            Mark Brouwer
            Keymaster
              • Expert

              Good point Rama, Thank you
              Refer also to:
              https://www.ureaknowhow.com/ukh2/round-table-1/33/907.html?p=7747&hilit=scraper#p7747

              quote kumarkrr post_id=10235 time=1626334962 user_id=10418:

              Scraper arms cleaning inside prill tower is a great safety concern in Urea Plant, as the same may lead to fatality. All over the world, numbers of accidents have occurred during physical cleaning of the urea deposition on scraper arms. At NFCL, scraper arms are cleaned without entering into prill tower scraper floor area. Entering scraper floor is dangerous even with safety protections like steel or wooden movable structures, helmet etc. Urea lumps will fall with high velocity due to the height and even small lumps also can cause severe injuries to the personnel working inside. Some industries are using movable steel structures under which workers carry cleaning. This problem can be solved by implementing following modification.

              Modification:

              A New Process Condensate line to scrapper floor with a Ring Header arrangement is to be arranged for washing the scraper arms. Also, a provision of rectangular hand hole for scraper chute is to be made for draining the washed condensate. This urea solution can be recovered by recycling to underground urea tank.

              Benefits:

              • No personnel will get injured after implementing this modification.
              • This modification will enable to take up arms washing while plant is in operation and no shut down required.
              • During turn around also, nobody needs to enter the scraper floor for cleaning.

              #102136
              Rama Raghava Kumar Kotti
              Participant
                • Expert

                Scraper arms cleaning inside prill tower is a great safety concern in Urea Plant, as the same may lead to fatality. All over the world, numbers of accidents have occurred during physical cleaning of the urea deposition on scraper arms. At NFCL, scraper arms are cleaned without entering into prill tower scraper floor area. Entering scraper floor is dangerous even with safety protections like steel or wooden movable structures, helmet etc. Urea lumps will fall with high velocity due to the height and even small lumps also can cause severe injuries to the personnel working inside. Some industries are using movable steel structures under which workers carry cleaning. This problem can be solved by implementing following modification.

                Modification:

                A New Process Condensate line to scrapper floor with a Ring Header arrangement is to be arranged for washing the scraper arms. Also, a provision of rectangular hand hole for scraper chute is to be made for draining the washed condensate. This urea solution can be recovered by recycling to underground urea tank.

                Benefits:

                • No personnel will get injured after implementing this modification.
                • This modification will enable to take up arms washing while plant is in operation and no shut down required.
                • During turn around also, nobody needs to enter the scraper floor for cleaning.

                #102135
                pbaboo
                Participant
                  • Expert
                  #102134
                  norozi1972
                  Participant
                    • Expert

                    Dear NASEEM
                    We faced with this problem and the cleaning of scrapper arm was very difficult. An idea from one of our engineering department expert ,we used a nano-paint to cover part of the scraper arm. After a while, the part was checked that the dust was very low and the lumps were easily removed.


                    Attachments:

                    #94223
                    Muhammad Kashif Naseem
                    Participant
                      • Expert

                      We are facing issue of frequent deposit of urea on prilling tower scrapper arms and causing damage to floor and scrapper .
                      Please share your experience, frequency of cleaning and coating material if any and impact of coatig on deposit.

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