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  • Saturday 11 November 2017

    [Why Required]Equalization line in distillation setup of Batch reactor

    Good morning all my dear readers......!!!

    Hope all having a happy weekend, Today i gonna explain you the purpose and significance of the Equalization line in batch reactor distillation setup, Yesterday i've received a message from Mr. Shyam Prasad(working as a production executive in a reputed pharma) through this site asking me to explain about it.

    First of all i'm happy after knowing that guys apart from process engineering also visiting this site and reading our posts. And Now i'll deliver it here in a simple and understandable way to all.

    But first of all everyone should know some basic things,

    What is Distillation ?

    Distillation is a process of separating solvents based on their relative volatility / boiling points.

    What is the major purpose of distillation in Pharma industry ?

    Usually in Pharma industry, distillation is used to concentrate a product layer, sometimes to remove any traces of unwanted solvents(simply called stripping/co-distillation, in other words chasing).

    What is this Equalization line ?

    Equalization line is used to maintain constant vacuum in the distillate collection vessel and the kettle/reactor.

    In what type of distillation this line is used ?

    It is majorly advantageous in vacuum distillation rather than atmospheric distillation.

    What will happen if the line is not included in distillation setup ?

    The major advantage with this equalization line is considerable amount of solvent recovery and it will also increase the efficiency of vacuum pump.

    With these above discussion, i think now itself you came to know its purpose and advantage, but i'll make it little clear to all in the remaining post.

    Usually the distillation setup in a batch reactor have two styles, i.e., one with equalization line and the other without.

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    Distillation Setup without Equalization line: 

    This is the traditional setup used in most of the companies, this setup is shown in the below fig.

    Traditional Distillation Setup

    1. Vacuum pump, 2. Trap, 3. Distillate collection receiver, 4. Condensers, 

    From the above fig you can clearly observe that the vacuum is generated at the pump and sucks the pressure from the pump trap, followed by the Collection receiver then condensers and finally Batch reactor through vapour line.

    It is obvious that the vacuum will be high at trap then collection receiver followed by condensers and then reactor.

    So if most of the cases the collection line will have a greater lengths as the receiver will be placed in the minus one floor of reactor(if its capacity is higher), sometimes receiver will be placed near by reactor(if the capacity is low). 

    If the capacity is low there wont be much issue, but in case if the receiver is placed in minus one stage of reactor then the condensed distillate will reach the receiver with some extra pressure and because of this pressure some of the vapour will be escaped into the receiver without getting condensed in the condenser, and the vapour will be further sucked into the vacuum trap, if the cooling efficiency is good the vapour will be cooled in the trap, or else it will enter the pump and the medium may get corrupt, which leads to drop in pump efficiency. 

    To address these issues the Equalization line concept is introduced. Lets see below where it need to be placed in a distillation setup.

    Also Read:

    Calculate height required for vapour line for distillation 
    NPSH required Vs NPSH available

    Distillation setup with Equalization line ;

    This is the innovative setup which is trending currently in most of the companies, this setup is shown in the below fig.

    Innovative setup - Current trend

    1. Vacuum pump, 2. Trap, 3. Secondary condenser, 4. Primary condenser & Distillate collection receiver,

    Equalization line is shown as dotted.

    If you can see here, the Vacuum line from the pump trap is connected to the secondary condenser and the distillate collection receiver is having two connections, one is collection line and the other is Equalization line.

    The vacuum will be high in trap then in secondary condenser and then in both primary condenser and collection receiver. So, whenever as discussed above if any uncondensed vapours escapes into the collection receiver due to the pressure exerted by the condensed distillate then those vapours shall be sucked back into the secondary condenser from the collection receiver through equalization line and then those uncondensed vapours shall be condensed in the secondary condenser.

    Because of these special effects of Equalization line the solvent recovery will be better in case of Distillation setup with Equalization line.

    That't it.......!!! Now i think you have clearly gotta idea and difference between the two setup's.

    If any queries kindly comment here / message us,

    Comments are most appreciated......!!! 

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    About The Author

    Hi! I am Ajay Kumar Kalva, Currently serving as the CEO of this site, a tech geek by passion, and a chemical process engineer by profession, i'm interested in writing articles regarding technology, hacking and pharma technology.
    Follow Me on Twitter AjaySpectator & Computer Innovations


    1. @ Ajay , plz share the scrubber design for API Pharmaceutical

      1. Dear Nitin,

        Sorry for not attending your request, saw your message on Linkedin also, New author is on the way, regarding Equipment design and all, they will take care, or else i'll try to post in my next post.

        AJAY K

      2. Dear Ajay,
        With PCB's intervention being increased these days, we are in high demand of Scrubber installation.
        So, please help on it ASAP

      3. Dear Ajay,

        How to decide from which point we should give the equalization line?

      4. Dear Anonymous,

        The equalization line should be dragged from the line which carried un-condensed vapours from primary condense to secondary condenser over to the collection receiver.

        Next time, kindly comment with your Name.

        AJAY K

    2. how to reduce filtration TIME CYCLE
      of water media in ANFD

      1. Dear Naveen,

        Need some information regarding the reaction mass that you need to filter,

        Whats the pH of reaction mass, density of reaction mass, % of solids in the reaction mass, whats the composition of solvent content(whether its a pure water or any mixture of solvents) ?.

        Pl provide the above mentioned data.

        AJAY K

    3. Will Equalization line help in enhancing recovery of low boiling solvents like Methylene chloride as well??

      1. MDC recovery is somewhat difficult, my suggestion is to go with a 3rd condenser.

        AJAY K

    4. Dear AJAY yours posts were so helpful for us and we pay thanks to u. we would be like to know the scrubber design for the given reaction mass (for eg: Aluminium chloride reactions).

    5. Dear Ajay we are greatful to you...
      Thank you
      If you know
      Please post something related to Automation

      Controllers (pi pd pid)
      Control valve functioning
      Rate gain

      Thank you
      Dheeraj kumar

      1. Dheeraj,

        I'm not that much familiar with those controllers.

        Ajay K

    6. Kindly let me know the what is the difference between equalization line and vapour balancing line where could be located in the batch reactor and use of each one how should we identified both lines

      1. Dear Ramaiah,

        Both were same, no difference, equilization line balances the vacuum in the receiver and the reactor.

        AJAY K

    7. when ever your applying vaccum to secondary condenser then is thier any chance to suck the solvent directly into the trap????

      1. Dear,

        There may be a slight probability but not everytime, which may be due to the development of back pressure in secondary condenser.

        Kindly comment with your real name next time.

        AJAY K

    8. Replies
      1. Dear Channesh,

        Pl make it clear.

        AJAY K

    9. Thanks a lot for sharing this with all folks you actually understand what you're speaking about!
      Bookmarked. Kindly also talk over with my web site =).
      We will have a hyperlink change arrangement among us

      1. lets make it a fair deal,
        write me at

    10. Dear Ajay,

      Why vapors will be escaped into receiver when reciever placed in minus one floor¿


      1. Hiii Philip,

        Good to see you again,
        Usually liquid will have higher density when compared to vapours, and as the condenser will have some congested space between the tubes and shell, the vapours wont be able to raise immediately and due to the higher vapour density of solvent , it will drive the vapours which come in contact with the condensate stream, and as once if the liquid condensate gains some velocity, it will be able to drive those un-condensed vapours into the distillate receiver even if it is in the minus stage.
        To bring those vapours back into secondary condenser, an equillization line is included in the setup.

        Best Regards,
        AJAY K


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    Hi! I am Ajay Kumar Kalva, owner of this site, a tech geek by passion, and a chemical process engineer by profession, i'm interested in writing articles regarding technology, hacking and pharma technology.

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