Use of let down energy from Hydrolyzer

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  • #114382
    Swetha
    Participant
      • Participant

      Dear All,
      In waste water treatment plant SAIPEM plant have horizontal deep Hydrolyzer which operates at 35 Kg/cm2 pressure, after treatment this 35 kg/cm2 solution send to distillation column which operates at 2.5 Kg/cm2
      The differential pressure of 32 Kg/cm2 have lot of pressure energy.

      Here thread of discussion is
      Does any plant are using this energy or worked upon this. If there is some work please share as energy saving is the need of the era

      Regards,

      Syed Muhammad Umair

      Hi,
      If you have ever simulated a water treatment system, especially the C06102 column, you will see that the large amount of energy transferred from R06102 to the lower part of the chimney tray contributes significantly to the energy needed for the distillation process. If you reduce this energy recovery, you will obviously need to compensate for it by using more steam, meaning that if you reduce the energy from the R06102’s condensate part of C06102, with the same load, you will have to increase the amount of steam used directly in the distillation process.
      Regards,

      Dear Sir,
      The proposal is for utilisation of Hydraulic energy available with the solution by dropping pressure from 35kg/cm2g to 2.5kg/cm2g. So I think on installation of Hydraulic Turbine there shall be only pressure reduction and no change in heat balance across the Hydraulic Turbine. Thus, there won’t be any requirement for increasing steam input to distillation tower.
      Please let me know in case I am wrong in understanding of using Hydraulic Turbine to utilise the energy of Contol valve in WWT from Hydrolyzer to Distillation column.
      Concept of installation of Hydraulic Turbine is similar to the application installed for pressure reduction of GV solution /MDEA solution in CO2 absorption section of Ammonia plants.

      #111705
      zavtranguyen
      Participant
        • Participant

        Dear All,
        In waste water treatment plant SAIPEM plant have horizontal deep Hydrolyzer which operates at 35 Kg/cm2 pressure, after treatment this 35 kg/cm2 solution send to distillation column which operates at 2.5 Kg/cm2
        The differential pressure of 32 Kg/cm2 have lot of pressure energy.

        Here thread of discussion is
        Does any plant are using this energy or worked upon this. If there is some work please share as energy saving is the need of the era

        Regards,

        Syed Muhammad Umair

        Hi,
        If you have ever simulated a water treatment system, especially the C06102 column, you will see that the large amount of energy transferred from R06102 to the lower part of the chimney tray contributes significantly to the energy needed for the distillation process. If you reduce this energy recovery, you will obviously need to compensate for it by using more steam, meaning that if you reduce the energy from the R06102’s condensate part of C06102, with the same load, you will have to increase the amount of steam used directly in the distillation process.
        Regards,

        #111703
        Ehsan ul Haq
        Participant
          • Participant

          Dear All,
          In waste water treatment plant SAIPEM plant have horizontal deep Hydrolyzer which operates at 35 Kg/cm2 pressure, after treatment this 35 kg/cm2 solution send to distillation column which operates at 2.5 Kg/cm2
          The differential pressure of 32 Kg/cm2 have lot of pressure energy.

          Here thread of discussion is
          Does any plant are using this energy or worked upon this. If there is some work please share as energy saving is the need of the era

          Regards,

          Syed Muhammad Umair

          #98351
          i-g-chaudhari
          Participant
            • Participant

            This reply is for Prabhat.
            Dear Prabhat you have prompted very good thread of discussion on energy conservation. We at GNFC have such system provided in new plant since design in amine base CO2 absorption plant where hydrulice energy is of letdown is used to drive feed pump by providing hydrulic turbine on same shaft. I also have same thoughts as you If you can workout feasibility of installation it can be in following lines.
            1. It is known that same pump can work as turbine if it is designed to run in other direction ( Please refer the attached file).
            2. An identicle pump is to be coupled on opposit side of motor.
            3 Hydrolyser out let from u/s of LIC is to be routed through new pump with an I/v & out let of pump will be connected in d/s of LIC . Nearly 60 to 70% of pumping energy can be recovered.
            4. If scheme works well addiotional controlls can be provided based on Hazop & for stability of system.
            This requires detail study & a level of commitment from management. If have it do it.
            Regards.

            I G Chaudhari

            #98349
            neerajrajesh
            Participant
              • Participant

              Members may refer to this scheme and comment.

              At present R-2 (Hydrolyser) offgas (~ 3Te quantity by material balance) is being mixed in C-2 (Distillation Tower) offgas line and further condensed in E-17(Overhead Condensor) . This way we not only are loosing the enthalpy of R-2 offgas which is at 35 kg / cm2 pressure and 235 degree C temperature but also significantly wasting this heat in cooling water. This also increases the cw requirement in E-17.

              In the scheme proposed, R-2 offgas mixed with small quantity of P-6 ( Hot Condensate Pump) discharge will be diverted to a small reboiler (proposed) where it will tranfer its enthalpy to MV-4 (Existing MS saturator) condensate (at 22kg/cm2 pressure & 220 degree c temperatures). When R-2 offgas will be condensed it will generate the same amount of MP steam in reboiler.

              R-2 offgas after condensation will go to V-8 (Reflux Drum) passing through a separator. This separator pressure shall be maintained at 22 kg / cm2.

              This scheme offers potential MP steam generation of 3Te/ hr.

              Neeraj

              #98299
              Mark Brouwer
              Keymaster
                • Expert

                Dear Norozi,
                Thanks
                Proposal of 145 to 4.5 Kg/cm2 letdown, I have already worked on that it had lot of operational complication.
                Let down from hydrolyzer to distillation column is not having any operational issues.thats why I am looking here.

                regards
                prabhat

                #98295
                norozi1972
                Participant
                  • Expert

                  Dear prabhat
                  I want to add another source for energy saving in the urea synthesis section. That’s Solution with 145 bar pressure from high pressure stripper to lp section with 4.5 bar pressure. I don’t heard any technology in urea plant but in Ammonia plant under MW keloge license , there is a process motive (co2 absorbtion system) for running a turbine. A benfild solution from absorber with 30 bar goes to a turbine as a motive and after that it goes to co2 stripper with 1 bar pressure.
                  With best regard
                  Khpc-iran
                  Norozi

                  #92988
                  Mark Brouwer
                  Keymaster
                    • Expert

                    Dear All,
                    In waste water treatment plant SAIPEM plant have horizontal deep Hydrolyzer which operates at 35 Kg/cm2 pressure, after treatment this 35 kg/cm2 solution send to distillation column which operates at 2.5 Kg/cm2
                    The differential pressure of 32 Kg/cm2 have lot of pressure energy.

                    Here thread of discussion is
                    Does any plant are using this energy or worked upon this.

                    Regards
                    Prabhat

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