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    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 Gearbox,
    * 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
    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
    0.7 - 0.85
    1/3rd of tank dia
    Backward Blade Turbine
    100 - 300 RPM
    5
    0.65 - 0.85
    1/3rd of tank dia
    Paddle
    50 RPM
    5
    0.03
    80% of tank dia
    Anchor
    50 RPM
    5
    0.07
    80% of tank dia
    Gate
    50 RPM
    5
    1
    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.!

    Agitators Curves for reference:







    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


    144 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
      2. please let me know any example for no of agitators, calculated based on a formula,
        No. of agitators = Z x rho / D,

        I dont understand

        Delete
      3. Dear Sir,

        Z is the liquid height in the reactor, rho is the density of solvent/rxn mass, D is the dia of reactor,

        Lets say, ours a 10 KL reactor, with height of 2.54m & dia of 2.4m.
        Lets assume liquid height of 2m, and reaction solvent is toluene, so
        no of agitators will be 2 x 0.868 / 2 = 0.868 ~ 1 impeller.
        that means one impeller is enough for the agitator.

        Hope you understand,

        Regards,
        AJAY K

        Delete
      4. Thank you Mr Ajay

        I mean that one impeller means one blade for agitator

        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
    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
      2. let me know I have one process was demanding to convert amorphous to crystalline i preferred that anchor 48 RPM occupancy 35% what will happen if occupancy increased
        also tell me what will happen if im going with PBT/RCB with low RPM with high or low occupancy can i get the desired form and PSD

        Delete
      3. Dear Sir,

        There wont be severe impact on the product nature based on agitator, but the forming crystal growth depends upon the agitator RPM, As you have mentioned that occupancy is ~35%, so if its Anchor reduce the RPM between 25-28, if its a PBT / RCI reduce them to 40-45. Then the crystal growth shall be good.

        First of all, as a process engineer we need to think about the yield, that shouldn't be lost during filtration in form of fine crystal through ML's, then after we can think about the PSD by going through jet milling etc.

        Regards,
        AJAY K

        Delete
      4. Thank you Mr Ajay i will be touch you

        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
    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
      Replies
      1. Please reduce centrifuging time or reduce rpm.But this will result in retention of some chlorofoem in product.It is a question of standardization.

        Delete
    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
    45. Sir,I can't understand this calculation,I have done it in paper but doesn't match with your result..
      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.
      Please show the calculation..It may be unit problm

      ReplyDelete
      Replies
      1. Dear Pratim,

        Sorry, that's a wrong calculation i've done over there, it is 47754.54 KCal,
        So, its gonna be, 8332.8 / 47754.54 = 0.174 hr = 10.47 mins.

        Regards,
        AJAY K

        Delete
    46. Ok sir ....Sir in which unit you have taken the conductivity value 1.03??
      How it is assumed?? Please rply

      ReplyDelete
      Replies
      1. Dear Prathim,

        For a MSGL surface, K holds 1.2 KW/m.K, which is equal to 1.03 KCal/hr.m.K

        Regards,
        AJAY K

        Delete
    47. I have a doubt about this problem..Sir,I am giving an example
      In our plant in a certain process there are 660lit toluene,165 kg ethyl cuma rone crude are charged into a 1.0kl glr to heat up to 102℃.Steam is available at 145℃ (inlet temp) and outlet temp around 70℃.Accroding to practical process it normally takes 90mins to reach around 102℃..But when I am going to calculate by the above process that you have written here it takes just around 10 mins...How this is possible sir even we assume fouling...???

      ReplyDelete
      Replies
      1. Dear Pratim,

        I think initially you have given some different input, and this input is different, anyway lets do it now,

        Solven t: toluene, Volume: 660 L, Reactor caapcity :1.0 KL MOC: GLR,
        Steam in: 145 degC, initial mass: 30 degC, final mass temp: 102 degC,

        Toluene density 0.87 Kg/L, Specific heat: 0.45 KCal/Kg.K,
        U : 120 KCal/hr.Sq.m.K, Effective HTA 2.81 Sq.m, Time for heating is: 1.13 hr = 67.7 mins

        Use this sheet for calculating the time for heating/cooling:

        https://drive.google.com/open?id=0Bxh-62TvI01VQ3RISWRMR3I5NFE

        Regards,
        AJAY K

        Delete
    48. Ok sir...Sir how you have taken the solid 165 kg ethyl cumarone mass into above calculation??I mean its Cp value and it's density ??

      ReplyDelete
      Replies
      1. Thats mass will be dissolved and wont have that much impact on our calculation, there will be slight variation in the specific heat, thats it.

        because the volume of the compound is far low when compared to that of the volume of toluene.

        Regards,
        Ajay K

        Delete
    49. Sir preciously you have said that as per your theory for time calculation better to go with moc thermal conductivity approach but here you have calculated as per heat transfer coefficient concept...Why is it so sir?Any special purpose

      ReplyDelete
      Replies
      1. While calculating with thermal conductivity, it doesn't need any data like fouling factors, or scaling thickness, it is pure theoretical, and if you want to proceed with overall HT coefficient, it is defined based on the above mentioned factors. once read this post: http://pharmacalc.blogspot.com/2016/05/overall-heat-transfer-coefficient-Calculation.html

        Thats why i've mentioned its better to go with thermal conductivity.

        Regards,
        AJAY K

        Delete
    50. Sir if we calculate time by moc thermal conductivity approach then what will be the result??

      ReplyDelete
      Replies
      1. The result will be pure theoretical and it is subjected to descaled equipment's. Surely it will vary based on fouling and scaling.

        Regards,
        AJAY K

        Delete
    51. For which solvent we would go for flash distillation and for which we go for fractionation??

      ReplyDelete
      Replies
      1. Fractionation and flash distillation were mostly applicable for petroleum industries,
        But in pharma industry, mostly we have vacuum distillations only, some times we will collect the low boils and high boils in some product manufacturing, so those can be considered as fractionation and regular single solvent distillation is considered as flash distillation.

        Regards,
        AJAY K

        Delete
    52. What is G force for centrifuge??
      Is it wR^2?
      How it affects in cf?

      ReplyDelete
      Replies
      1. Cf = ( omega ^ 2 ) x r - Centrifugal force.

        Omega - angular velocity(rpm).

        Higher centrifugal force favors higher rate of filtration, but it shouldn't be done in continuous flow, it should be applicable for only for batch process, i.e., spin dry.

        Lower centrifugal force favors optimized rate of filtration, this is applicable for feeding operation.

        Regards,
        AJAY K

        Delete
    53. How we calculate time required for performe cf operation for a certain mass of reaction mass and certain bd suppose 1.6 gm/c.c and having mass 1000kg

      ReplyDelete
      Replies
      1. I'll explain you the formula, pl try to calculate, still any queries while calculating use the forum page available in this site and pl start a new thread(instead of commenting),

        Rate of filtration = { rho x (omega^2) x [(R2^2) - (R1^2)] }/{2 x myu x X }

        X = [(M x A / Al x Ak) + (R/A2) ].

        rho - reaction mass density, omega - angular velocity(RPM)
        myu - viscosity of solution, M - solids conc in reaction mass,
        A - Specific cake resistance, R - filter cloth resistance,
        Al - log mean of cake area : 6.28 x b x (R2 - Ri) / ln(R2/Ri),
        b - centrifuge basket height, Ak - arithmetic cake area : 3.14 x b x (Ri+R2),
        A2 - 6.28 x R2 x b,

        R1 - distance between centrifuge center to the liquid surface over cake,
        Ri - Basket dia - cake dia.
        R2 - Basket Dia,

        Regards,
        AJAY K

        Delete
    54. After calculating TR for a chiller plant how we will calculate it's costing depending on current consumption??

      ReplyDelete
      Replies
      1. Dear Pratim,

        A brine chiller of capacity 150 TR consumes 400 amps current per hour,

        Use power formula, P = V x I x Cos(phi).

        V is voltage in volts, I is current in amps, Cos(phi) is power factor, usually it will be around 0.85 - 0.90.

        Commercial power supply will be 440 V, for domestic purpose it will be 240 V.

        P = 440 x 400 x 0.85 = 149600 watts = 149.6 KW.

        For commercial it will be 3 phase supply, so P = 1.732 x 149.6 = 259.1 Kwatts.

        For commercial purpose, 1 unit costs about Rs. 9/- i.e., 2331.9 /- .

        So for 150 TR the consumption is 2331.9 /-.
        And along with this you will have a compressor running for ammonia and a motor running in evaporative condenser.

        Based on their motor capacities, calculate the same .

        That's it, these are maintainence costs apart from the methanol and water costs.

        Regards,
        AJAY K

        Delete
    55. Sir you have told that "A brine chiller of capacity 150 TR consumes 400 amps current per hour," but sir TR to amp conversation first we need to TR with 12400 to get total BTU then multiply it with .293 to get watt then divide it with volts(for commercial 440) then we get amps as amps=watt/volts...In this method for 150TR amps getting differ form your result... Sir please tell me how you have calculated the 400amp for 150TR

      ReplyDelete
      Replies
      1. Dear Pratim,

        Never convert the TR into Amps, in my previous comments i mentioned you the chiller capacity is 150 TR and it took 400 amps, it may vary from medium to medium, like brine to chilled water.

        Regards,
        AJAY K

        Delete
    56. Ok sir...
      Sir how bulk density of the reaction mass/wet material (after cf followed by drying operation) has its effect on pharma production?

      ReplyDelete
      Replies
      1. Bulk density indirectly effects the time cycle and investment costs,

        If the bulk density is high then the cake volume will be less, then automatically the equipment used for the process requires low capacity.
        and it can impact the time cycle, by reduction of filtration lots, drying lots.

        Regards,
        AJAY K

        Delete
    57. What are the preventive tools that must have a reactor for safely operation?

      ReplyDelete
      Replies
      1. Not tools, those are called instruments, PRV & RD's are extensively used for safe operation in reactor, not only reactors but also they can be used for most of the vessels to relief the pressures which are developed due to the breathing losses, reactions or sometimes during inertization.

        regards,
        Ajay K

        Delete
    58. Please say something about RC1,DSC and MIE study??What sort of info we can get from those experimental data?

      ReplyDelete
      Replies
      1. Dear Pratim,

        RC1 data indicates the energy liberated/required during an addition or during a reaction.

        But where as, DSC study indicates the Onset & Peak of decomposition temperature, sometimes it indicates the endotherms also.

        MIE value will indicate the static energy generation probability, if it is low then it required more controls.

        Regards,
        AJAY K

        Delete
    59. Replies
      1. Dear Pratim,

        pl start a discussion through new topic thread in the below forum, instead of commenting.
        http://discussion-forum.80757.x6.nabble.com/

        Regards,
        AJAY K

        Delete
    60. Supoose Design pressure of a reactor is 4kg/cm2,then approximately what will be the set pressure of the safety valve of that reactor if I want to install?

      ReplyDelete
      Replies
      1. Dear Prathim,

        For PRV it shall be 2.75-3 Kg/cm2, for RD it will be 3.0-3.5 Kg/cm2.

        Regards,
        AJAY K

        Delete
      2. would PRV & RD be installed on the same line or separate lines?

        Delete
      3. PRV & RD should be placed parallely, they shouldn't be installed in series.

        Delete
    61. Sir,why generally baffle is not used GLR?? Because of not having sufficient strength to hold baffle or any other reason??

      ReplyDelete
      Replies
      1. Dear Pratim,

        Usually the GLR surface will be high sensitive, and it will be difficult to arrange baffles with support from GL surface, and if any hanging baffles were arranged, then there may be a chance of glass lining damage if those were detached during process operations leading to unsafe situation.

        Hence, considering the safety issues, the baffles concept is terminated.

        Regards,
        AJAY K

        Delete
    62. hello, I have 2 tanks of 20000 litre and 50000 litres ,have to mix salt with the water so which type of agitator should be useful....please suggest

      ReplyDelete
      Replies
      1. Dear Shivam,

        Pl go with the agitator having least bottom clearance / minimum stirring volume, as salt is highly soluble in water, there wont be any issue with mixing pattern,

        Preferably go ahead with gate anchor.

        Regards,
        AJAY K

        Delete
    63. Sir
      I Mechanical engineer in my agitator I have 2 sets of hydrofoil blade (each set contains 3 blades) and one set of curved blade at bottom there is always faliure of blade breaking in it ( this agitator agitates slurry of sodium bi sulphate) and brg failure (taper roller) I am unable to find out reasons of such faliure ....
      May you help
      Sweep dia 1250mm
      Tank dia 2500mm
      Tank height 4000mm approx
      Distance B/n two set of blade vertical 1100mm

      ReplyDelete
    64. Sir in our plant water is circulated by a pump with flow 3.5m3/hr and discharge press 3kg/cm2 to ,a venturi is attached with the circulation line to receive vacuum in receiver from there vacuum is supplied to the plant,pipe sizing of the circulation line is 2"..You can say it is water ejector system. sir my question is is there any calculation to find out what maximum vacuum can be generated by this system??Pls response sir...

      ReplyDelete
      Replies
      1. Dear Pratim,

        it is simple to determine the ejector capacity, as already you have mentioned its a venturi, go with below formula,

        Capacity = C x A x ( ( 2 x dP / ρ ) ^ 0.5 ),

        C - Coefficient of discharge = 0.98
        A - Cross sectional area of venturi,
        dP - Pressure drop across venturi,
        ρ - Vapour density of solvent.

        Regards,
        AJAY K

        Delete
    65. Thank you Sir..I have calculated the value of P1-P2=2.97 kg/cm2 ..P1=3kg/cm2 developed by the pump which will be same at upstream of venturi and P2 will be the pressure at downstream that means in throat of the venturi.Lowering the pressure at throat is the main cause of generating vacuum..So from the above P2=.0291 kg/cm2 or 22.1 mmHg that means vacuum generated is 760-22.1=737 mmHg ...Am I right Sir??? Please response...

      ReplyDelete
    66. What are the conditions required for getting different types of agitations like mild
      Normal
      Vigorous and violent on maintaining what parameters we can get different type of agitations

      ReplyDelete
      Replies
      1. Dear Rama,

        These conditions can be created by varying the turbulence,
        If we need to create these conditions by varying RPM, we need to have different agitators, and also with the help of baffles we can create that.

        Regards,
        AJAY K

        Delete
    67. How to calculate steam temperature by its pressure for reactor utility

      ReplyDelete
      Replies
      1. Hiii Keyur,

        Refer this post,
        http://pharmacalc.blogspot.com/2018/04/steam-tables.html

        Best Regards,
        AJAY K

        Delete
    68. Hello sir,
      what are the design equations of CSTR?

      ReplyDelete
    69. Can you share the reference materials for these data, charts and other contenet.

      ReplyDelete
      Replies
      1. Hello Yakesh,

        Attached the charts of various agitators for your reference.

        Best Regards,
        AJAY K

        Delete
      2. Can you share reference books for these data.

        Delete
      3. There are no reference books buddy, collected from some sites

        Delete

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