imran-idris

Forum Replies Created

Viewing 15 posts - 1 through 15 (of 16 total)
  • Author
    Posts
  • in reply to: MOC Vent piping and Drain Pot #96499
    imran-idris
    Participant
      • Participant

      We also had CS piping for close drain system at our TOYO licensed Urea plant. It is obviously done to save cost. We replaced that piping with SS-304 four years back. So far no problem has been faced.

      in reply to: Preservation of steam piping network for long shutdown #96498
      imran-idris
      Participant
        • Participant

        Dear Mr. Hanafiah, thank you very much for your in time reply. I just wanted to ask weather putting instrument air in steam line for their preservation is a standard practice or not? If yes! can you please share any reference for this practice? As in order to put this thing in practice I need some reference / document to justify it in front of higher management.

        Thanks & regards,
        Muhammad Imran

        in reply to: World highest urea production? #96433
        imran-idris
        Participant
          • Participant

          Engro Fertilizers Limited has been operating Single stream Urea plant with a capacity of 3835 MeT/d since Dec-2010. They have demonstrated 3700 MeT/D Urea production. So I believe this is the biggest now…

          in reply to: Test HP NH3 pump #96314
          imran-idris
          Participant
            • Participant

            Apparently there does not seem any issue apart from the fact that the specific gravity of the BFW is 1.0 and for liquid Ammonia it is 0.6. So just evaluate power requirements accordingly and see if pump motor is adequate to provide required amount of power.

            in reply to: Relation temperature and %NH3 in water #96307
            imran-idris
            Participant
              • Participant

              vapor liquid equilibrium curves for Ammonia-Water system are available in literature for different temperatures. You can consult those or if you are interested in simple solution, then use hysys or some other simulation software to predict Ammonia absorption in water at different temperatures and pressures.

              in reply to: Carbon Formation in Reformer #96306
              imran-idris
              Participant
                • Participant

                I have been working at the most updated Ammonia producing plant where S/C ratio is operated as low as 2.6 and Primary reformer outlet temperature is as high a 800 C and we don’t face any carbon formation at these conditions. SO Thermodynamically speaking you are safe upto 800 C with your S/C ratio as low as 2.6.

                in reply to: Explosivity off-gas MP inerts washing tower #96244
                imran-idris
                Participant
                  • Participant

                  Usually at all plant Sp and TOYO plants fresh Ammonia coming from Ammonia plant contains 2~3 NMC (methane+Nitrogen)/ MeT of Ammonia and it has never been hilighted as a problem. I doubt that adding NG in MP abosrber would pose an issue in booster pump. In fact the amount of NG needed is also not very high.

                  in reply to: Malfunctioning of HP Stripper liquid outlet V/V #96234
                  imran-idris
                  Participant
                    • Participant

                    Dear Inban, usually stripper level controller is part of plant shutdown logic and will tend to close in case the level goes too low or plant goes towards shut down due to any other reason. By operating this valve on hand jack you are defeating ESD system. In that case you should have a back up plan to cater for any emergency that may arise during hand jack operation.
                    regards,
                    Imran

                    in reply to: Explosivity off-gas MP inerts washing tower #96219
                    imran-idris
                    Participant
                      • Participant

                      I am totally in agreement with Mr. S K Gupta and in my opinion adding natural gas in MP absorber at plants where MP vent gas is either flared or used in furnace is the best option.
                      Mr. S K Gupta! can you please share a PFD / P&ID for referenced modification at some Indian plant?
                      regards,
                      Imran

                      in reply to: Vacuum system problems #96218
                      imran-idris
                      Participant
                        • Participant

                        Vacuum is mainly affected by the performance of surface condensers, so if we focus to address the things which affect heat transfer coefficient for surface condensers 80% of the issues would be resolved. Things which affect heat transfer coeffieient of a condenser are
                        1- Mixing of non condensing gases (inerts) with condensing media: heat transfer coefficient of a condenser decreases drastically in the presence of inerts. Only one percent inerts in steam can decrease heat transfer coefficient by 15%. So look out of air ingress to your vacuum system, flanges are the most vulnerable parts for inerts ingress to the vacuum system. Sometimes steam fed to the ejectors also contains inerts, see if your deaerator is working well.
                        2- Reduced cooling water velocity in condenser tubes: Remember cooling water temperature is not that important in case of condensers, it is the velocity of cooling water that matters the most. Vacuum will not break unless liquid leg temperature reaches around 55 C. Due to this fact some of the plants are using tempered cooling water is also being used to increase velocities through condensers. Dedicated cooling water booster pumps can also be installed to get required flow through the condensers
                        3- Online cleaning system for surface condensers can help a lot in improving and maintaining better heat transfer coefficient vacuum condensers.
                        4- High Ammonia / CO2 in vapors for separators would reduce OHTC, for that increase LPD bottom temperature to as high as possible and reduce LP loop pressure as low as possible.

                        Rearards,
                        Imran
                        https://www.thepetrostreet.com/forums/

                        in reply to: Maintaining stability of urea above melt point #96217
                        imran-idris
                        Participant
                          • Participant

                          As far as I know Urea chemistry, maintaining molten Urea above its boiling point and not letting the formation of by-products can be achieved by storing molten Urea under positive pressure of Ammonia above its boiling point. In this way you can avoid the formation of Biuret and Ammonia(g) which are favored by low pressure.
                          As we know the reaction
                          Urea (molten) <=> Biuret + Ammonia
                          So according to LeChatlier’s principle, increasing pressure and adding Ammonia above molten urea solution would shift the reaction equilibrium towards left side of the equation hence preventing formation of by products.

                          in reply to: H2SO4 injection in urea melt #96216
                          imran-idris
                          Participant
                            • Participant

                            Mr. Ting Nguk Sing, as per your experience decrease in flow definitely indicates cavitation which we all know results in developed head of the pump, flow rate and finally amperage, but it seems from previous discussion of Mr. Inban that decrease in flow has not been experienced which means that there is least possibility that the pump cavitates in this case.

                            in reply to: H2SO4 injection in urea melt #96211
                            imran-idris
                            Participant
                              • Participant

                              Dear MR. Le Ngoc Ban, I have few queries regarding reduction in pump discharge pressure & amparage.
                              1- Have you observed any drop in melt flow through pump as a result of your experiment?
                              2- Have you experienced any abnormal sound through pump or there was any rise in pump vibrations?
                              If you have not experienced any of the above symptoms then it is not cavitation, its just that either
                              1- the density of the pumped fluid has decreased, but this fact cannot be supported because of the fact that decrease in density would result in increase in volumetric flow rate for the same plant load. So this change can be considered minimal (as required power is directly proportional to cube root of increase in flow through pump). However
                              2- change in viscosity of the pumped fluid can change significantly be the addition of ionic compunds like H2SO4 which would ultimately result in low pressure drop in the discharge line.

                              Please also look at this aspect of the issue as well which is quite positive one if the above mentioned observations are not captured during your experiment.

                              Regards,
                              M. Imran Idris

                              in reply to: Blowing Procedures #96210
                              imran-idris
                              Participant
                                • Participant
                                in reply to: Stopping of Ammonia Boost up Pump #96209
                                imran-idris
                                Participant
                                  • Participant

                                  I have some queries regarding your working
                                  1- Where would you send the recovered Ammonia (Ammonia recovered through MP Absorber)?
                                  2- From Where would you feed Reflux Ammonia to MP absorber to avoid CO2 carryover from MP absorber?

                                  Ammonia received from Ammonia backend is equivalent to fresh makeup required to maintain level in Ammonia reservoir at Urea plant, but Ammonia going to HP Ammonia pump is the sum of recovered Ammonia from MP Absorber and fresh Ammonia makeup. Usually the ratio of fresh Ammonia & Feed Ammonia to Reactor is around 0.7. So even with directing fresh Ammonia to HP Ammonia pump suction you’ll have to pump 30% of Ammonia through booster pump.
                                  Moreover as fresh Ammonia is relatively at lower temperatures, it helps in reducing Ammonia losses from MP vent.

                                  Regards,
                                  Imran.Idris
                                  https://forums.thepetrostreet.com/

                                Viewing 15 posts - 1 through 15 (of 16 total)
                                UreaKnowHow

                                UreaKnowHow.com is an independent group of nitrogen fertilizer specialists with an impressive number of years experience in designing, maintaining and operating nitrogen fertilizer plants.

                                Solution Providers offer their solutions to improve our member’s plants performance.