An Engineer's Choice

  • Thursday, 5 May 2016

    Types of Agitators, Agitator's Design and Significance


    Hello readers.....!!
    Today i gonna give you a description that limits upto my knowledge, and most of you may find it useful, about the Industrial Agitators, Types of Agitators, their Power Numbers, Design Equations and their significance in production.

    Introducing or discovering the types of agitators in pharma field is certainly a revolution because different agitators will have different purposes and different advantages, but most commonly used agitators are Anchor, Propeller, Turbine, Paddle etc., and still these agitators are sub divided into types, for example Round Anchor and Anchor combined with Gate are two types of Anchor.

    So, for knowing the types of agitators and their significance you don't need any basic knowledge, but just an idea that

    "what is an agitator ?, And what it can do ??"  
    "What is the difference between Agitation and Mixing ??"
    Agitator : An agitator is something which is used to stir liquid or mixture of liquids.

    Also Read:


    How to Select a Condenser?
    What Does a TR exactly means? 
    How to Calculate the Energy of Steam?

    What it can do ?? : It can be used in various operations, in a pharma industry it can be used in multiple operations like reactions, work up's, drying, filtration, etc.,

    Difference between Agitation and Mixing :


     Agitation is the process of keeping a mixture that has been mixed in the proper mixed state required for the 'end' product.

    Mixing refers to the actual stirring of different liquids and/or materials to blend them together into an end product or mixture. Once this mixture is 'mixed' it may require agitation to keep the mixture in the proper 'mixed' state.

    So, Now i'll go into our topic,

    There are two types of Agitators commonly used,

     1. Mechanical Agitators, 2. Electronically Controlled Agitators, I'll demonstrate commonly used Mechanical Agitators.


    Recommended For You:


    How to Select Motor Capacity of an Agitator? 
    How to do Scale Up calculations? 
    How to Design an Industrial Column?


    Paddle Agitators: This is one of the most primary types of agitators with blades that reach up to the tank walls. Paddle agitators are used where an uniform laminar flow of liquids is desired.



    Anchor Agitators : This simple agitator consists of a shaft and an anchor type propeller and can be mounted centrally or at an angle. It is mainly used in reactors.



    Radial Propeller Agitators : Radial agitators consist of propellers that are similar to marine propellers. They consist of two to four blades that move in a screw like motion, propelling the material to be agitated parallel to the shaft.



    Propeller Agitators : A propeller agitator is shaped with blades tapering towards the shaft to minimize centrifugal force and produce maximum axial flow. Propeller agitators are popular for simple mixing jobs.



    Turbine Agitators : Yet another type of process agitator is the turbine agitator. Turbine agitators can create a turbulent movement of the fluids due to the combination of centrifugal and rotational motion.


    Helical Agitators : These agitators have blades with a twisted mechanism, just like the threads of a screw. The curves result in a vigorous motion of the fluids to be agitated. Helical agitators are most useful for mixing viscous liquids. 



    A simplified brief description has been tabulated below. 

    Agitator Type Applications Advantages Disadvantages
    Paddle
    * Mixing of Solids,

    * Slurry Mixing,

    * Used during Crystals
     forming phase during
    Super saturated Cooling
    * Heavy duty,

    * Apt for Slow operation,

    * Can have 2 or 4 blades
    * Power Consumption
    is very high,

    * Inefficient Mixing
    Turbine

    *Straight Blade
    *Pitched Blade
    *Curved Blade
    *Disk Blade
      * Liquids and Gas reactions,

      * Highly used during
      Reaction and Extraction
      Operations.
      * Generates high
       Radial Flow,

      * Highly used for
       dispersion operations
      * Not preferred for
      solvents with high
       viscosity[NMT 20 cP]
      Screw type * Have to use in addition
       to other agitators.

      * Mostly used in Food processing.
      * Uniform mixing
      of High viscous
      masses.
      * Not preferred for im-miscible solvents.
      Helical Blade

      *Ribbon Type
      *Helical Screw
        * Most Probably used in
        Paint industry.
        * Can handle Visco
        -elastic liquids efficiently
        * Low possibility for Radial mixing
        Anchor * Highly used in Pharma Industry for Several Operations * Increase possible heat
         transfer rate in reactors,
        from reactor heat transfer surface
         to Mass.
        * Required high
        Efficiency Gear
        box,
        * Required high Power.
        Gate * Highly used for blending Operations * Provides efficient
        Mixing and agitation control,
        * Can handle Psuedo
        -plastic liquids.
        * Not preferred
        when both liquids and gases combine
        involves 
        Propeller * Suitable for GLR's,
        ANFD's, can handle Corrosive materials with Glass lining.
        * Will increase the homogeneity,

        * Can be used in two different patterns for
        drying and pressing. 
        * Need to be operated
        at high speed to
        avoid solid settlings
        in reactors.

        * Need to be
        operated at low speeds in drying operations.

        Diameter of Agitator: Usually the diameter of agitator depends on the Diameter of the vessel,

        It is generally 1/3rd the diameter of the tank for Marine Propeller, Axial flow turbine, Turbo Propeller, Disc Blade turbine, Flat Blade turbine, Backward Blade turbine.

        It is generally 4/5th of the diameter of the tank for Paddle, Anchor, Gate.

        Type of Agitators and their functions:

        Marine Propeller is generally an item produced by casting process in a foundry and it has 3 or 4 blades. Cast agitators have two basic advantages, uniformity of material and hard surface. These have tapering blades, and angle of blade varies from root to tip. This produces maximum axial flow. The diameter of Marine Propeller impeller is 15% to 30% of diameter of tank. These have tip speeds between 300 to 500 meters per minute.

        Axial Flow Turbine, Turbo Propeller and Flat Blade Turbine have blades ranging from 3 to 6. These have tip speeds between 200 to 300 meters per minute. The diameter of impeller is 25% to 60% of tank diameter. For Axial Flow Turbine and Turbo Propeller, the angle of blade varies from 30 degrees (for less viscous liquids) to 60 degrees (for more viscous liquids). Standard angle is 45 degrees. Power requirement increases with higher pitch angle. For Flat Blade Turbine, the length of blade is 25% of diameter, and disk diameter is 60% to 70% of the diameter of impeller.

        Paddle, Anchor, or Gate have only 2 blades. These extend close to the tank wall and have tip speeds between 80 to 150 meters per minute. These push and rotate the liquid in a laminar flow. There is no axial or radial mixing. The width of blade is 1/8th or 1/10th of the agitator diameter.

        Number of Agitators:

        There can be many number of agitators connected to a shaft, and it can be calculated as 

        Number of agitators = (Maximum liquid height x specific gravity) / Diameter of tank.
        Gap between two Agitators = Liquid height / (Number of impellers - 0.5). 
        Basic Design Equations for a Vertical Vessel and Agitator:

        Vessel Volume = (pi x vessel dia x vessel dia x vessel length) / 4.0
        Agitator Shaft length = vessel length + (vessel dia x 0.25)
        For Rectangular Tanks,
        Tank Volume = Vessel Length x Vessel Breadth x Vessel Height

        Agitator Shaft length = Vessel Height

         Based on geometry of vessel, many factors for impeller can be decided.

        Agitator Speed Power Number Pumping Factor Impeller Diameter
        Marine Propeller
        100 - 300 RPM
        * 0.3 for 3 bladed impeller,
        * 0.33 for 4 bladed impeller
        * 0.33 for 3 bladed,
        * 0.34 for 4 bladed.
        1/3rd of tank
        dia
        Axial Flow Turbine 100 - 300 RPM * 1.35 for 3 bladed,
        * 1.4 for 4 bladed,
        * 1.45 for 5 bladed,
        * 1.6 for 6 bladed.
        * 0.6 for 3 bladed,
        * 0.69 for 4 bladed,
        * 0.78 for 5 bladed,
        * 0.87 for 6 bladed.
        1/3rd of tank
         dia
        Turbo Propeller 100 - 300 RPM * 1.35 for 3 bladed,
        * 1.4 for 4 bladed,
        * 1.45 for 5 bladed,
        * 1.6 for 6 bladed.
        * 0.6 for 3 bladed,
        * 0.69 for 4 bladed,
        * 0.78 for 5 bladed,
        * 0.87 for 6 bladed.
        1/3rd of tank
        dia
        Disc Blade Turbine 100 - 300 RPM 5.0  0.7 - 0.8 1/3rd of tank
         dia
        Flat Blade Turbine 100 - 300 RPM 5.0 0.7 - 0.85 1/3rd of tank
         dia
        Backward Blade Turbine 100 - 300 RPM 5.0 0.65 - 0.85 1/3rd of tank
         dia
        Paddle 50 RPM 5.0 0.03 80% of tank
         dia
        Anchor 50 RPM 5.0 0.07 80% of tank
         dia
        Gate 50 RPM 5.0 1.0 80% of tank
         dia

        AGITATOR COMPARISON CHART:

        Today, the major concerns of the chemical and pharmaceutical industries are improving performance and reducing production costs. Agitation, mixing and heat transfer are major factors in maximizing the efficiency of a process.  The various blade designs in our agitator product range have undergone significant research and testing, making it possible to use a scientific approach to agitation and heat exchange techniques that will optimize your process. The chart below illustrates the different types of blades available and the characteristics of each.







        That's it.........!! Cheers..... if you understand, 

        Excel Sheet has been simulated for design of Agitator and you can download it here,



        Any Queries feel free to ask,

        Comments are most appreciated.!


        Note: Some of the Data Interpreted here is not of my own, but from a generous Genius "Satish Lele"


        Related Articles:


        How to calculate Reactor Heat Transfer Area ? 
        How to calculate Distillation Time cycle ?
        How to select a Vaccum pump ?
        How to Calculate Volume occupied by Torispherical Dish ?
          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

        83 comments:

        1. which utility is suitable for condensing acetone vapours under vacuum and under atmposphere in condensor...chilled water 8 deg. centigrade or brine -10 degree centigrade..

          ReplyDelete
          Replies
          1. Hey Mr.Anonymous, if you are having two condensers, then go with chilled water for primary and chilled brine for secondary,
            and if you are able to maintain the vapour temperature above 15 deg C under vacuum, then go with -10 degC Brine or 5 degC chilled water, if the temperature below 15 degC then use chilled brine at -20 degC, and in case of the vacuum distillation, remember to have a equalisation line from secondary condenser to collection receiver,

            if the distillation is an atmospheric one, directly go with RT water at below 30 degC,

            Delete
          2. Can you explain theoretically and calculate and tell how to select utility as per the above post.pls. give ur mail id so that i can share the sketch..

            Delete
          3. using a better utility for condenser will enhance the rate of distillation, for a chilled brine at -10 deg C, the temperature difference can be considered as 7-8 deg C, and for a utility like chilled water having a inlet temperature of 8 deg C, the temp difference will be around 3-4 degC, because the reaction mass temperature will be around 15-20 degC under vacuum, so mostly the vapours will reach equillibrium with utility outlet, and in the process of condensing the vapour will exchange only latent heat, whereas in case of -10 degC brine, there will be exchange of sensible heat also, and if you want to calculate it theoretically then read the post in this link, then you will get a clear idea,

            http://pharmacalc.blogspot.com/2016/09/how-to-calculate-rate-of-distillation.html

            try to do a reverse calculation basing upon the fixed rate of distillation and find the LMTD of both cases, which uses brine at -10degC and chilled water at 8degC, then you will come to know the difference.

            Delete
        2. Hello sir,
          I am chemical engineering student I am doing my final year project on extraction of oil from slurry in oil refineries.can you suggest us some ideas

          ReplyDelete
        3. so i think, it is something like Lube oils refining, right??

          Thats a good one, and i too tried that during my project but finally got diverted, Give your best good luck,

          and regarding extraction any possible help i'll do, mail me @ pharmacalc823@gmail.com

          ReplyDelete
        4. Please tell me how to do piping? How to design pipeline Header and Tappings from it?

          ReplyDelete
          Replies
          1. A x V = A1 x V1 + A2 x V2 + A3 x V3 +......................
            But, V = V1 = V2 = V3 = .............. [this is as per thumb],

            A = A1 + A2 + A3 +................

            D^2 = D1 ^2 + D2 ^2 + D3 ^2 + ..............

            that's it,

            the number of tappings given should satisfy the above derived eqn.


            Regards,
            PHARMA ENGINEERING

            Delete
        5. what is the major difference between impeller,propellerand agitator

          ReplyDelete
          Replies
          1. Mostly there wont be anything like a Propeller, may be i've mentioned above that's just for understanding purpose, because Propeller is what you see in a table fan, and the agitator that was usually called as propeller in pharma industry is strictly called as Retreat curve agitator,

            Coming to your question, Impeller is nothing but an agitator, and for example if an retreat curve is having two agitators then it is said to have 2 impellers.
            That's it.

            Delete
        6. How can we calculate power for propeller & anchor used in glass lined reactor....

          ReplyDelete
          Replies
          1. Let it be a 10KL GLR, and the dia be 2.5m, and RPM is 110, by thumb dia of propeller will be 1/3rd of reactor dia,
            For Propeller,

            D = 2.5/3 = 0.83m, N = 110 rpm, rho = 1000 Cu.m / Kg, Np = 1.5

            P = 1.5 x 1000 x ( ( 110/60 ) ^ 3 ) x ( 0.83 ^ 5 ) = 3641 Watts = 3.64 KW,

            For Anchor.

            D = 2.5 x 0.8 = 2m, N = 48 rpm, Np = 5,

            P = 5 x 1000 x ( (48/60) ^ 3 ) x ( 2 ^ 5 ) = 81920 Watts = 81.9 KW.

            That's it..........!!!!

            Delete
        7. Hi,
          Great site, and great work.
          We are a 30 year old manufacturing firm specializing in chemical and pharmaceutical reactors. We are currently looking for professionals who can independently design agitators for the process and mechanical aspect. If you know any such individuals, please ask them to reach out to me at anuj@thermotechengg.com.

          Cheers
          Anuj

          ReplyDelete
        8. how can we design spray ball ..how to select number of holes and flow from holes in spray ball?

          ReplyDelete
          Replies
          1. Hello, as like previously mentioned, A*V = ( A1 * V1 ) + ( A2 * V2 ) + ( A3 * V3 )+................,
            V = V1 = V2 = V3 = ............,
            So, A = A1 + A2 + A3 + ........,
            (D^2) = (D1 ^2) + (D2 ^2) + (D3 ^2) + ........,
            D is line size, D1, D2, D3,....... are nozzle sizes, for how many nozzles the equation satisfied, those many nozzles you need to consider for a spray ball.

            Regards,
            PHARMA ENGINEERING

            Delete
        9. Great site sir I have ever seen ... Definitely I will mail ot post my queries....
          Parth Panja
          Kolkata

          ReplyDelete
          Replies
          1. Thanks and you can feel free to comment your queries.

            Regards,
            AJAY K

            Delete
        10. How agitator speed is calculated??How you can say in the previous problem that for Anchor type agitator RPM=48 and for propeller rpm=110??

          ReplyDelete
          Replies
          1. Those are basic things Pratim, Usually an anchor will have RPM of 36/48, a propeller will have from 96/110, a PBT will have 96-140.

            If you wanna calculate them then use the power to power number relation and consider physically available cases in your industry for getting diameters.

            Regards,
            AJAY K

            Delete
        11. So if I have to design an PBT agitator for a reactor,can I fix the value of rpm in between 96 to 140??Then can I calculate the power of the motor required to drive the same agitator based on the rpm?

          ReplyDelete
          Replies
          1. Dear Pratim,

            Regarding an agitator design all you can do is managing the L/D ratio, simply sweep dia you have to fix, then no of agitators, these can be calculated based on a formula,
            No. of agitators = Z x rho / D,

            Z - reaction mass height, rho - density, D - inner dia of reactor/vessel.

            RPM can be adjusted based on the Gearbox ratio, motors RPM will be either 1475 or 2900,
            usually motors with 1475 RPM will be preferred for reactors, and 2900 RPM motors used for centrifugal pumps,

            As mostly all reactors shall be equipped with VFD(Variable frequency Drive) at any time you can adjust the RPM.

            Power = Np x ( N^3) x (D^5) x rho.

            For more infor on motor capacity selection for an agitator, follow this link,
            https://pharmacalc.blogspot.in/2016/05/motor-selection-for-agitator.html

            Regards,
            AJAY K

            Delete
        12. In an In-process reaction, 60kg ammonia gas is needed to purge to the liquid phase reaction in a reactor.If I am going to calculate the total volume of the reaction mixture in litre(including ammonia) then how I will take the amount of ammonia as it is the gas phase and when it will take to solution it would liquify? Please help me Sir

          ReplyDelete
          Replies
          1. At what temperature you are purging??
            Based on the temperature below are the densities,
            -50 degC - 695Kg/Cu.m,
            0 degC - 636 Kg/Cu.m,
            20 degC - 609 Kg/Cu.m,
            50 degC - 561 Kg/Cu.m.

            If its 20 degC, then 60 Kg / 609 Kg/Cu.m = 0.0985 Cu.m = 98.5 L.

            Regards,
            AJAY K

            Delete
        13. Thank you so much Sir...I am really greatful to you...

          ReplyDelete
        14. I am working as a process engineer at an mnc pharma company,just joined.. unexperienced,that is why I am facing some problem.Please sir keep in touch..

          ReplyDelete
          Replies
          1. I'll be in touch with my site, you keep on visiting, that's it.

            Regards,
            AJAY K

            Delete
        15. Sir,how debottle
          necking is performed?

          ReplyDelete
          Replies
          1. It can be done on several ways, by having a change in equipment or change in process, or adding one more equipment, de bottle necking means it may be regarding time-cycle / quality / yield / anything that may be a hurdle in a process to overcome.

            Regards,
            AJAY K

            Delete
        16. My company has two sites...From one site, a process flow chart of a standardized product has come to my site and I have the responsibility to take that product in my site, depending on the equipment facility,capacity I have to take the batch in my site there by I have to fix the batch size. So sir what di you think what way would be better to go?Is there any data TT data required from another site or how much size of batch would be better to take trial?

          ReplyDelete
          Replies
          1. Before taking a batch, compare the equipments from transferee site to transferrer site, if the equipments were like to like including agitators, MOC, L/D ration & occupancy of reactors, filtration area of equipments, dryer's occupancies, then you can take a direct batch. or else go with a trail batch by ensuring minimum similarties like MOC & occupancy.
            TT data includes safety studies like RC1 data(Heat of reaction), DCS study(Decomposition temperatures & Enthalpy), ARC studies, powder safety data(MIE & Burning class).
            QbD(Quality by Design) studies and Design space report to have a better knowledge on the reaction parameters which effect yield and quality.
            Previous failure history of the product in their site.

            These are most recommended Doc's that need to be considered exchange during TT.

            Regards,
            AJAY K

            Delete
        17. Is it possible to get fine Crystal in glass reactor in the time of crystalization??By changing geometry of agitator?

          ReplyDelete
          Replies
          1. Go with an Anchor with 48 RPM

            Regards,
            AJAY K

            Delete
        18. Any explanation??Why does it so happen?

          ReplyDelete
          Replies
          1. There are 4 types of agitation[defined based on scale of agitation],
            1. Mild,
            2. Normal,
            3. Vigorous,
            4. Violent.
            For an anchor, if the anchor is having an RPM of 48, it will e either Vigorous / Violent, based on the occupancy. If the occupancy is about 60-80% then it will be violent.
            If the RPM is either violent / Vigorous, then the crystal size will come fine.

            Regards,
            AJAY K

            Delete
        19. Is there any thumb rule how to calculate minimum stirring volume of a certain capacity (e,g 5kl) of reactor?

          ReplyDelete
          Replies
          1. There wont be any thumb rule for calculating MST, but you can use bottom extension teflon blades to ensure your required MST.

            Regards,
            AJAY K

            Delete
        20. what is tips speed exactly sir???

          ReplyDelete
          Replies
          1. Tip speed is just nothing but product of sweep dia and agitator speed

            Regards,
            AJAY K

            Delete
        21. Please sir reply how order of the reaction influence in scale-up?

          ReplyDelete
          Replies
          1. I don't have enough knowledge about Scale-up vs reaction order, Infact being frank upto my experience i've heard about these things.

            Regards,
            AJAY K

            Delete
        22. But sir frankly speaking in an interview of torrent pharma ltd I have been asked this question from their AGM

          ReplyDelete
        23. Sir is it possible to calculate the time taken for distillation of 1000L acetone from a reaction mixture?Or any other data is required??

          ReplyDelete
          Replies
          1. Whats the total volume of reaction mass?, whats the MOC of reactor?
            whats the capacity of reactor?

            Regards,
            AJAY K

            Delete
        24. How cycle time & debottlenecking is performed by using recovery solvents?

          ReplyDelete
        25. It would be better sir if you give explanation using an example

          ReplyDelete
          Replies
          1. Refer this post.
            http://pharmacalc.blogspot.com/2016/03/theoretical-way-to-determine-time.html

            Regards,
            AJAY K

            Delete
        26. What is best possible way to centrifuge sticky reaction mass?

          ReplyDelete
          Replies
          1. Dear Pratim,

            Move with a low RPM i.e., ~300 during feeding, Expel the ML's at 600 RPM, wash the material at 400 RPM, Spin dry the material at 700 RPM followed by 900 RPM finally, its a sticky mass means the pH should be above 12 i think.

            Regards,
            AJAY K

            Delete
        27. What is the necessaity of nitrogen rotameter in PP area?

          ReplyDelete
        28. Why final crystalization stage is done separated area?

          ReplyDelete
          Replies
          1. Usually atmosphere pressure will be 760 torr,
            And to avoid any foreign particles from contaminating the product, final stage shall be done at clean rooms,
            The reason behind having many rooms in a clean room is,
            The main entrance shall be maintained at 768 torr, the next to entrance room shall be maintained at 774 torr, the production room / powder processing room shall be maintained at 780 torr, i.e., when you open the door of the production room then due to high pressure when compared to other room there is only chance of one way particle transfer i.e., from 780 torr room to 774 torr room, and when you open the door from 774 torr room, particles will transfer from 774 torr room to 768 torr room,
            and no two doors can be opened at the same time.

            Thats it

            Regards,
            AJAY K

            Delete
        29. PP area means Powder processing area

          ReplyDelete
          Replies
          1. In powder processing areas, usually you need to purge nitrogen but not flushing, because flushing may disturb the particle count, which need to be maintained mandatorily

            Regards,
            AJAY K

            Delete
        30. hello sir, can u please help to what the process engineer role in pharma and what is the basic knowledge for process engineer

          ReplyDelete
        31. To increase yield of a batch process generally what parameters should be manipulated? What basic ideas/thoughts should keep in mind??

          ReplyDelete
          Replies
          1. Dear Pratim,

            This seems to be a general question, be specific, so that i can answer, gimme any process outline with parameters, so that i can explain you in detail.

            Regards,
            AJAY K

            Delete
        32. In reactor when a reaction mass is thick,difficult to take in centrifuge through outlet of the reactor,what precautions should be taken or what modification on the lining between the reactor and cf should be taken?

          ReplyDelete
          Replies
          1. Dear Pratim,

            Use a flush bottom valve at reactor bottom, at what temperature and pH you are trying to filter the mass ?
            avoid any negative bends in the line, better have a straight line from reactor bottom to centrifuge, dont reduce the line size from reactor bottom to centrifuge, is possible use a metering pump, if the temperature of filtration is above RT then add hot / cold insulation to the line, as every one knows reduce the RPM of reactor while feeding, so that you can achieve continous flow, maintain the centrifuge RPM between 300-400.

            Regards,
            AJAY K

            Delete
        33. Sir how utility calculation of a batch is performed??

          ReplyDelete
          Replies
          1. Dear Pratim,

            Be specific to me, vacuum, steam, RT water, chilled water, Power, Chilled brine, liquid nitrogen, Nitrogen, Instrument air were all considered as utilities in our pharma field, so about which utility shall i need to discuss about.

            Regards,
            AJAY K

            Delete
        34. Approx for a 200kg batch size(suppose there are a drying operation where 650mm Hg vacuum is required and for another one steps where 0-5℃ temp is required for 300kg reaction mass),how would I approach to calculate how much vacuum and chilled brine will be required??

          ReplyDelete
          Replies
          1. In first case, whats the solvent you want to remove and in second case,

            Lets the mass weight be 300 Kg and let the volume be 3000 L, then you need to calculate the TR required for cooling the mass to 0-5℃, i.e.,

            [ 3000 x 1 x 0.5 x ( 30 - 0 ) ] / 3024 = 14.88 TR,

            If u need to calculate the time of cooling or heating pl read this post: http://pharmacalc.blogspot.com/2016/04/calculate-time-cycle-required-for-heating-cooling.html

            Regards,
            AJAY K

            Delete
        35. Sir normally what is load calculation for pharma industry??

          ReplyDelete
          Replies
          1. Dear Pratim,

            Be specific.

            Regards,
            AJAY K

            Delete
        36. Sir I have been given a task to prepare a solvent monitoring report which includes consumption of solvent(fresh+recovered) for every product producing in our plant and also make a plan how amount of consumption of fresh solvent is reduced and use more recovered solvent so that saving can be possible on solvent consumption.As per standard process requirement we can not reduce the amt of solvent requirement for a batch(reaction/washing/extraction etc).So as a process engineer how would I approach or in which area I would focus to reduce amount of feesh solvent consumption???Please sir give me suggestion

          ReplyDelete
          Replies
          1. Dear Pratim,

            Use fresh solvent for reaction, and recovered solvent for washing / extraction.

            Regards,
            AJAY K

            Delete
        37. how to calculate vacuum required for a batch?

          ReplyDelete
          Replies
          1. Dear Pratim,

            Based on solvent boiling point and material senstivity.

            Regards,
            AJAY K

            Delete
        38. Generally we know that pumps deals with liquid and compressor deals with air/gas then how we can use vacuum pump for creating vacuum by driving off air??
          And how oil rings vacuum pump operates??(Is it operated by circulating oil?)

          ReplyDelete
          Replies
          1. Dear Pratim,

            An oil ring rotary vane vacuum pump has an impeller with blades attached to a center hub, located in a cylindrical body, but off-set from the center. When the pump starts, the impeller slings the liquid sealant by centrifugal force, to the outside walls of the body, forming a ring of oil at the outside walls of the body creating suction which is created in the connected system through a filter housing.

            Regards,
            AJAY K

            Delete
        39. How would I calculate amount of chilled brine required for chilling(0-5℃) operation?

          ReplyDelete
        40. Sir suppose for a batch of 1kg in pilot there is step to heat up the reaction mass of volume 3lit from 30℃ to 70℃ which takes time 1:30hrs (In a Glass assembly of 5.0 L, depending on thermal conductivity etc).Then for same batch if take it in commercial scale of batch size 100kg and of the said step is taken in a GLR of capacity 1.0KL how much time it would to reach 70℃?? I possible show the calculation for this scale up please consideeing increase of heat transfer area etc..
          Taking toluene as solvent.
          Steam pressure 3.5kg/cm2
          Steam temperature=100℃

          ReplyDelete
          Replies
          1. Dear Pratim,

            Reaction mass volume is 600 L, major solvent is toluene,
            1 KL will have a HT area of 4.25 Sq.m,
            Effective HT area(A) will be 4.25 x ( 600 / 1000 ) = 2.55 Sq.m,

            LMTD = ( ( 100 - 30 ) - ( 100 - 70 ) ) / Ln ( ( 100 - 30 ) / ( 100 - 70 ) ).
            = 47.17 degC.

            Sensible Heat (S) = 600 x 0.868 x 0.4 x ( 70 - 30 ) = 8332.8 KCal.

            Time = 8332.8 / ( 120 x 2.55 x 47.17 ) = 0.577 hr = 34.62 mins.

            If you want to calculate based on the glass lined properties, then

            you need to calculate K x A x dT / X = 1.03 x 2.55 x ( 70 - 30 ) / (2.2 x 10^-3) = 4918.72 KCal/hr.
            That means a GL surface can trnasfer 4918.72 KCal of heat energy in 1 hr.
            So it will take 8332.8 / 4918.72 = 1.69 hrs = 102 mins for transferring 8332.8 KCal heat energy.

            Regards,
            AJAY K

            Delete
        41. Hello Sir,

          I am working at Lupin Ltd..

          In one of our product, the isolation is done in centrifuge..The CF is SS 48".. The issue is the wet cake becomes hard and during unloading we need to use scrapper which causes the CF bag damage..

          Is there any means available by which we can avoid the usage of scrapper..

          The solvent is chloroform..

          ReplyDelete
        42. Here whose overall heat transfer coefficient value is 120 which you have used??

          ReplyDelete
        43. Sir you have written in the above statement against my question that
          Time = 8332.8 / ( 120 x 2.55 x 47.17 ) = 0.577 hr = 34.62 mins.
          Again you have calculated time required to reach 70℃ ,it will take 8332.8 / 4918.72 = 1.69 hrs = 102 mins for transferring 8332.8 KCal heat energy.
          Then my question is what does the time value of 1st time signify?

          ReplyDelete
          Replies
          1. Dear Pratim,

            The first calculation is based on the over all heat transfer coefficient of the reactor, this may vary based on scaling and fouling factors,
            and the second calculation is based on the thermal conductivity of the reactor MOC.

            Regards,
            AJAY K

            Delete
        44. Then Sir which one of these would be better to take into consideration?

          ReplyDelete
          Replies
          1. As per my theory i'll go with the MOC thermal conductivity.

            Regards,
            AJAY K

            Delete

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        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.

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