Drain ammonia to ammonia water tank or vent stack ?

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Viewing 14 posts - 1 through 14 (of 14 total)
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  • #101847
    montaser
    Participant
      • Participant

      If there is a crack in Ammonia water tank, we have a modified empty new tank, what is the possibility to repair this crack without Shutting down the urea plant or operating with low load for example: 90%?
      As we will use the modified tank instead of the ammonia water tank and made a connection (tie-in) between two tanks to emptying the ammonia water tank in order to deliver it for repairing and welding WORK.
      Please give me your advice and experience.

      #101580
      engahmed84
      Participant
        • Expert
        quote pbaboo post_id=9309 time=1578020279 user_id=4841:

        Dear Friends, good discussion, good contribution by everyone and in addition-
        I think the ammonia venting through vent stack is the very dangerous for environment, Atmospheric ammonia (NH3) has long been recognized as the key important air pollutant contributing to eutrophication and acidification of ecosystems.
        Advantages of Draining through Closed drain into waste water tank
        1. The process recommended ammonia through closed drain into waste water tank and every line is designed for minus 32 degree cent for ammonia system.
        2. Some load will be increased in waste water section (means steam requirement will be increased in Distillation tower), But ammonia will be recovered, ammonia is very costly than steam.
        3. Every process is total recycle process so the ammonia must be recycled.
        4. Now a days advanced process have some buffer tank to hold up the solution like ammonium carbonate and also designed for shut down solution hold up.(e.g.-Carbonate solution tank(V-10).
        5. This is the routine practice to hand over HP ammonia pumps, filters, and ammonia booster pumps, all ammonia must be recovered through waste water section.Ammonia can not be vent as per some acts & Laws for environments and pollution.

        Regards,
        Prem Baboo

        perfect analysis

        #101579
        norozi1972
        Participant
          • Expert

          quote mohamadkamal78 post_id=9300 time=1577558401 user_id=5652:

          So you are saying it is better to drain ammonia via vent stack that is right?

          Yes my friend

          #101575
          pbaboo
          Participant
            • Expert

            Dear Friends, good discussion, good contribution by everyone and in addition-
            I think the ammonia venting through vent stack is the very dangerous for environment, Atmospheric ammonia (NH3) has long been recognized as the key important air pollutant contributing to eutrophication and acidification of ecosystems.
            Advantages of Draining through Closed drain into waste water tank
            1. The process recommended ammonia through closed drain into waste water tank and every line is designed for minus 32 degree cent for ammonia system.
            2. Some load will be increased in waste water section (means steam requirement will be increased in Distillation tower), But ammonia will be recovered, ammonia is very costly than steam.
            3. Every process is total recycle process so the ammonia must be recycled.
            4. Now a days advanced process have some buffer tank to hold up the solution like ammonium carbonate and also designed for shut down solution hold up.(e.g.-Carbonate solution tank(V-10).
            5. This is the routine practice to hand over HP ammonia pumps, filters, and ammonia booster pumps, all ammonia must be recovered through waste water section.Ammonia can not be vent as per some acts & Laws for environments and pollution.

            Regards,
            Prem Baboo

            #101571
            Bhupen Mehta
            Participant
              • Participant

              Huge water volume will be required to collect the ammonia in ammonia-water tank due to ammonia-water saturation point at ambient conditions

              #101567
              mohamadkamal78
              Participant
                • Expert

                So you are saying it is better to drain ammonia via vent stack that is right?

                #101566
                norozi1972
                Participant
                  • Expert

                  Hi every body
                  Happy new year to Dear Mark and his colleague and to all Friends.
                  I think the following reason can be consider:
                  1) Usually the flow and quantity of ammonia for draining to ammonia water tank is very low.
                  2)From environment of point of view it is important for collecting of any ammonia and hazardous material.
                  3) for producing of such ammonia , some energy will consume therefore it is better to recycle it again to process Instead of venting to atm.
                  with best regard
                  norozi

                  #101564
                  Mark Brouwer
                  Keymaster
                    • Expert

                    Dear Friends

                    A very interesting discussion !

                    Who has experiences with failures of piping / equipment in the liquid ammonia drain systems ?

                    #101560
                    engahmed84
                    Participant
                      • Expert

                      but if it is dangerous to drain ammonia directly to tank and if drain piping is not suitable or can crack under diff. in temp. , this procedure is applied for several years in many plant and at least we did not suffer from any damage in ammonia drainage system

                      also do you think that draining directly to vent stack will not increase possibility of venting more ammonia vapor to atm. than using the ammonia water tank as an intermediate … knowing that drainage to tank from ammonia system should be done at very low rate due to hammering and inc. in temp. and conc. of tank after drain

                      also does material of construction of vent stack can handle direct drainage of pure ammonia and withstand the drop in temp. (cooling shocks) ?

                      #101546
                      mohamadkamal78
                      Participant
                        • Expert

                        Dear Muhammad,

                        In the piping system for liquid ammonia , all the drains are directed to ammonia water tank not to vent stack like drains of HP ammonia pumps and candle filter on the suction of theses ammonia pumps, so if it more safe to drain ammonia to vent stack why all drains are directed to ammonia water tank?

                        Thank you

                        #101544
                        muhammad-umar-riaz
                        Participant
                          • Participant

                          Dear Mohamad kamal,

                          Mostly ammonia circuit piping is designed to cater cold embrittlement impact of Ammonia while filling ammonia circuit and draining/venting ammonia as at lower pressure when ammonia gets evaporated it causes sudden Colling i.e. cold embrittlement, that is why ammonia circuit filling is carried out by first pressurizing ammonia circuit with N2 in order to avoid exposure of ammonia piping at very lower pressure, similarly during depressurization of ammonia circuit when ammonia pressure gets lower than N2 (utility header) pressure ammonia further depressurization would be carried out under N2 pressure due to similar effect as mentioned earlier.
                          Ammonia circuit piping also protected against these sudden cooling shocks by providing MOC (material of construction) as Killed Carbon steel (see specs. on google). If you drain liquid ammonia in ammonia water tank firstly it will cause sudden cooling and may lead to cracks in the pipeline at downstream of ammonia circuit, secondly liquid ammonia when evaporate in ammonia water tank it will ultimately increase pressure and release in the atmosphere and poses safety concern. That is why it preferred not to drain liquid ammonia directly to ammonia water tank but evaporate it to vent header, from where it could be absorber in showering water/condensate and finally recovered in ammonia water tank.

                          Regards,
                          Muhammad Umar Riaz
                          Sr. Process Engineer
                          Urea plant (Stamicarbon Technology)

                          #101542
                          mohamadkamal78
                          Participant
                            • Expert

                            We suppose that drain of pure ammonia to vent stack is less hazardous than to drain to ammonia water tank as there is no hammering and ammonia further go to ammonia water tank after overflow from vent stank but with lower pressure

                            #101533
                            engahmed84
                            Participant
                              • Expert

                              vent stack is supposed not to have pure ammonia like that in ammonia system !!!

                              #93890
                              mohamadkamal78
                              Participant
                                • Expert

                                What are the potential hazard from drain ammonia to ammonia water tank as some people prefer to drain to vent stack which in turn direct ammonia to ammonia water tank.
                                Is there a difference in draining ammonia of HP ammonia pump or ammonia filters between ammonia water tank and vent stack.

                                Thank you

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