Thursday, 28 April 2016

[How To] Select Pump and Motor, Line sizings.



The most interesting topic for an Engineer is Pumps and their Properties, And the most irritating one is theory of Fluid mechanics, May be no one will accept this but they will laugh inside when they hear this,

 I said it is the most irritating because many of the Engineers during their Engineering studies they feel it difficult to get through that subject and after once crossing that subject, it will be the most appreciable subject that a student ever choose, Now i'll go deep into matter but before that you need to gain some Knowledge regarding this topic or else it will be difficult to digest the main topic.

 The Main confusion arises and being frank many of the fresher engineers cant spot out the exact difference between the pump and the motor also, because due to a fear that has been created during their bachelors life in Engineering, But 
Credits: Pharmacalc.blogspot.com
a Pump is something like an equipment which is supposed to transfer the Liquid matter from a low sea level point to high sea level point, simply from bottom to top through lines applicable, in other words mechanical energy to kinetic energy.
Here the Kinetic Energy will be delivered through the Impeller that has been Shown inside the pump cross-section. The Parts can been clearly in below pic.
Credits: pharmacalc.blogspot.com
And What is a Motor??
Credits: pharmacalc.blogspot.com
a Motor is the source connected to a Pump which supplies the required high frequency motion to the Pump for transferring the liquid, simply which converts Electrical energy to Mechanical Energy. 
The Above Motor pic shows you that How the produced Mechanical Energy will be delivered through its Drive-End shaft. And if you wanna have an idea about How this Electric Energy is converted to Mechanical Energy, I'll explain you later.

 How Pumps are Classified??

 Usually pumps will be classified into 3 types, Reciprocating, Rotary, Centrifugal, but in industry point of view 99% Centrifugal pumps will be considered, and these Centrifugal pumps can be classified into two Types, 1. Self priming pumps, 2. Non- Self priming pumps. For Explanation regarding these two types see the below pic.
Credits: pharmacalc.blogspot.com

 If you clearly see the Self priming pumps will try to fill the impeller cavity itself before pumping to discharge end, so the advantage here is even if the suction end is empty also it can avoid priming, that means these pumps don't need marines connected to the suction end to hold on some level in line. These type of pumps will be regularly used in ETP flow lines as they will have somewhat high level suspended solids, and usually these self priming pumps will have a closed impeller.




 And while coming to Non-Self Priming pumps, these needs marines to be connected at the suction end to avoid priming, if there is no marine connected, then they may undergo priming and the impeller would run empty and there will be chance of pump failure. Usually these sort of pumps will be operated with open impellers.
Also Read:


 Now, you will have one more question in mind, what is Priming??
Priming is nothing but just formation of air gaps/pockets, which won't allow proper Pumping.

 So, Now you are Upto the Mark to go into the Actual Topic.
HOW TO Select Pump and Motor, Line sizings.

 Selection of Pumps:

 Pumps will be Selected based on the requirement basis only there won't be any theoretical calculations, but you need to know some specification on which we go for pump selection, Usually a pump specification will consist of following,

 1) Pump Capacity: Pump Capacity characterizes Upto which extent it can generate a flowrate, the flowrate it will usually define is for water. Basically the rate of Pumping depends upon the Impeller diameter and the Motor RPM.

 This how an Impeller Looks like:



2) Head: This seems very important, because without this our pump will be nothing, the pump greatness lies in the Head that it can pump. The key point here to remember is if the head of the pump is mentioned to be 20 meters then it can be used only upto that 20 meters, whatever the linesize it may be.

3) Motor Required: Motor requirement is nothing but the capacity motor which is compatible for this pump tow work with maximum possible efficiency.

 These are the main points in a specification to observe.

 Pump Efficiency can be calculated from the Ration of Water Horse Power to Brake Horse Power.

 Efficiency = Water Horse Power / Brake Horse Power(Shaft power)

 Motor Selection:

 Usually a Motor will work on Electrical Energy and generates Mechanical Energy, but not 100%, because it will also will have some factor of efficiency, this Efficiency depends on the Brake Horse Power of Motor, Rate of Pumping depends upon the Motor RPM.

 Efficiency of Motor = Shaft Power out[Watts] / Shaft power in [Watts].

 So now everyone is well aware of the above mentioned basics,

 Now i'll Directly jump to point of calculating the Hydraulic power required to do pumping for a differential head,
Power ( P ) = ( Q x Rho x g x h ) / (3600000 x N )

 Where, P     - power in KWatts,
            Q     - Liquid Flowrate in Cu.m/hr,
            Rho - Density in Kg/Cu.m,
            h      - Differential head in meters,
            N     - Efficiency ,
Also Read:


 Now i'll Show you how to calculate for example i need to pump 30 Cu .m /hr at a differential head of 20 m, my solvent is water, and i'll consider the efficiency as 90%,

 So, P =  30 x 1000 x 9.80665 x 20 / ( 3600000 x 0.9) = 1.816 KW = 2.43 HP.

 My required Motor capacity is 2.43 HP ( 1.82 KW ).

 And Now another Item i need to calculate is the required Line size,

 For Pumping 30 Cu.m / hr, i need how much size??

 Usually line size can be calculated as per thumb rule, by considering the velocity in between 1.5 m/s to 2.5 m/s,

 But to provide you with some clarity in this, i'll give you a small data for considering the velocities based on viscosity,
Velocity       Type
 0.6-0.9      Viscous
 1.5-2.5     Non- Viscous
If you need to calculate the required line size from the velocity, use this formula,
D, mts  = ( 1.2734 x Q / V ) ^ 0.5.

 That's It, Cheers........, Any Queries happy to hear, Will be there to Solve,

 An Excel Sheet For Our Readers From Our Side, Download It Here

 Comments are Most appreciated



Also Read:

         How to Calculate Volume Occupied by the Torispherical Dish End? 

 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


at 17 comments:

Sunday, 24 April 2016

[How To] Calculate Energy of Steam


Today i'm gonna give you a brief about Steam properties especially Energy, as there will be much confusion about types of Steam. 
What is the Energy of Steam, How much energy from steam can we utilize, How much Energy it needs to get generate, These are the questions that we don't have a clear cut answer, if you have then there is no need to read this, or else you have to.....!!!  

For a liquid to have transition to Vapour stage, it need to cross the following steps,

* First the liquid need to reach Boiling point
* The liquid need to change its state from Liquid to Vapour,
* The vapour still heated above evaporation temperature, simple called Super Heating.

And for going deeper into, need to have much clear knowledge regarding Steam types, and on what basis it has been classified. Usually upto my knowledge steam will be mostly Classified based on its energy, but there wont be any ranges to define its type, and coming to types below are some,

1. Saturated Steam,
2. Dry Saturated Steam,
3. Super Heated Steam.

Saturated Steam: The vapor produced from water which is produced at or after water boiling point [100°C or 212°F] is called Saturated Steam.

Dry Saturated Steam: The saturated steam produced after Removal of Wetness is called Dry saturated steam, usually 99% of the pharma operations were carried out using Dry saturated steam, and the rate of Condensation of Dry Saturated steam will be lower than that of Saturated Steam.

Super Heated Steam: Super Heated steam is what when produced after heating the Dry Saturated Steam to further temperatures, Highly dangerous it cant been seen, even the dry saturated steam can be observed but Super Heated cannot.    

Enthalpy ( H ): Enthalpy is nothing but the product of Mass in a system ( M ) and Specific Enthalpy ( h ). 
 H = M x h

Also Read:



Specific Enthalpy ( h ): Specific Enthalpy is summation of Internal energy ( U ) and Product of Absolute Pressure ( P ) and Specific Volume ( V ).

h = U + ( P x V )
 So, Now most of you got a brief about Enthalpy and Steam, Now lets begin our Actual Journey towards of Destination of Calculating the Steam Enthalpy,
This Can be done in 3 stages,
Img. Credits: Engineering ToolBox.


Stage 1: Enthalpy of Saturated Water:

Standard Enthalpy of Saturated Water at Standard Atmosphere is 419 KJ/Kg,

Specific Enthalpy of water can be calculated as

hf = Cw ( TL - To )

Where, hf  - Water Enthalpy, Cw - Specific Heat of water =4.19 KJ/Kg.°C,
Tf - Saturation Temperature ( i.e., Boiling point temp.), To - Reference Temperature ( Ice point Temp.)

Stage 2: Specific Enthalpy of Saturated Steam:

This Enthalpy for Saturated Steam can be obtained at atmospheric pressure from above Table, i.e.,
hg = 2676 KJ/Kg,

So now Enthalpy required for saturated liquid to convert into saturated steam can be obtained as follows,

Latent Heat ( he ) = hg - hf = 2676 - 419 = 2257 KJ / Kg.

Stage 3: Specific Enthalpy of Super Heated Steam:

This is what every one needs, 

 How to Calculate the Energy of steam if it is having temperature higher than its boiling point,
Specific Enthalpy of Super Heated Steam can be calculated from the regular equation,

hs = hg + Cp ( Ts - Tf )

Cp - Specific Heat of Steam at Constant Pressure, which can be considered as 1.860 KJ/Kg.°C,
 Ts - Temperature of super heated Steam, Tf - Saturation temperature i.e., 100°C.

As Cp varies with temperature, just have approximated values somewhat higher.

If you Understand all the above logic , then Cheers, or else if you have any queries than feel free to contact us, thanks :)

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

Also Read:


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


at 8 comments:

Friday, 22 April 2016

[How To]Calculate the Power Required for an operation



Good Day viewers..!!

 Today i wanna explain you guys how to Calculate the power required for an operation and also how to calculate operating costs for power during an operation, especially in Pharmaceutical industries.

 Basically everyone knows the traditional way of calculating the power consumption, but it can't be applied to every case as the Load during the operations will vary everytime, and the one we calculate will give us the power for full load and we will be having many cases like,

 1. Motor operating at full loads,
2. Motor operating at empty loads,
3. Motor operating at peak loads,
4. Motor operating at intermittent loads.

 So without knowing these all, One cannot calculate the power exactly, and some of you may not know the secret formula of many who are calculating the power by traditional way.

For Calculating the power consumed by a 5hp motor, everyone will go on multiplying 0.746, and reply you with a figure 5 x 0.746, and in addition without asking they will also multiply the returned figure from 5 x 0.746 with 8 or 9, and tell you the amount for that operation to show their talents.
But Actually this Calculation wont give you the exact figure, as this is not an exact calculation as previously i mentioned you that load will vary depending on the operation from time to time,

Even some persons may argue that 1HP = 735.5Watts and some argue as 1HP = 746 Watts,
And Both of them were correct because when we define Horse Power in british units it will be 735.5 Watts and For English Units i.e., S.I. it will be 746Watts.

 And before going onto the main calculation part i want you guys to know some basic theory regarding the Motors, that were designated for handling operations. 99.9% of all the motors were provided with VFD ( Variable Frequency Drive) to save the power, and these VFD were provided with a display meter, for displaying the motor running frequency and the Load ( in Amp's), and percentage Load.

VFD - Used for Changing the Frequency
Basically the frequency and the current are not related directly, but whenever the frequency is changed immediately you can observe a variation in Current consumption, 

A 1 hp Motor will Consume 1Amp of current for 100% load.

And coming to Classification of Loads, 

1. Motor Operating at Null Load: It means there is no load over the motor, but in case of empty load also our motor will consume some Amp's as our shaft needs some mechanical torque for its rotation, so for that it will consume some load.

2. Motor Operating at Intermittent Load: It means when there is some resistance to the movement of the shaft of the motor then the current required may vary, so this is what Intermittent Load means.

3. Motor Operating at Full Load: For a Motor operating at full loads it needs complete current i.e., if its a 5hp motor it will consume 5Amp's.

4. Motor Operating at Peak Load: If a Motor operating at peak load means it has crossed the full load i.e., 100% limit and still operating, you may not believe this but its true, because many vendors will provide the motors with a certain service factor, 

And now you may get a doubt that "What is a service factor?" 

 A Service Factor is nothing but some additional capacity provided over the full load limit for a Motor to function in Emergency cases, if a Motor of 10HP is having a Service Factor of 1.15 then it will be functional upto 15HP, and if this limit is exceeded then the Motor will be tripped.
So, i think if you can understand the mentioned concept 100%, then you are ready to learn the Calculation, Anyway i'll start this ,

 For Calculating the power consumed by a Motor we have to simply use the formula,
P = V x I x Cos(phi)
Here, V - Voltage in Volts, I - Current in Amp's, Cos(phi) - Power Factor,

 I think you are much familiar with Voltage and current than the Power Factor, Power Factor is nothing but ration of the Load and Impedance, these terms are much more comfortable for electrical students, so i'll turn off this matter here itself, if not you may loose your interest in reading this. But better to get a sight of the below Formula,


X - Load, R - Resistance, Z - Impedance.
Z = SQRT( (R x R)+(X x X))

We may consider this power factor in between 0.80 to 0.92,

Generally the Voltage supply for Domestic usage will be 240 Volts i.e., Single Phase,
But for industries it will be 440Volts supply (Commercial purpose) i.e., a Three Phase supply, and the whole power need to be multiplied with Square Root of 3 (1.732),

So, Finally for Calculation we have to use the above mentioned Power Formula just like the below mentioned example,

Power Consumption Calculation for a 20HP Motor, current consumed is 16Amp's ( from VFD),

It will be P(Watts) = 440 x 16 x 0.85 x 1.732   For Three Phase,
                              = 240 x 16 x 0.85                For Single Phase,

 here the Power Factor Cos(phi) is considered as 0.85,

 So for Three Phase commercial purpose it will be P = 10364 Watts = 10.364 K Watts
     For Single Phase Domestic Purpose it will be P = 3264 Watts = 3.264 K Watts.

 That's it Cheers, Done

 Still have any queries feel free to Ask, We are happie to help,

 Comments are most appreciated.

 Stay Tuned for more...........!!!!
Also Read:

About The Author

Hi! I am Ajay Kumar Kalva, Currently serving as the CEO of this site, a technoholic 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


at 6 comments:

Thursday, 21 April 2016

[How To] Design a Condenser



Hello Readers.......!!
Good Day to all, Today i want to make a Demo on Basic Condenser Design Aspects, which involves the calculation of Heat Loads, Utility Loads, Overall Heat Transfer Co-Efficient. 

 So Before entering the point i want you guys know something basic knowledge which helps you in better understanding of this. The Beginning point is what is Latent Heat and What is Sensible Heat, and what is the Major Difference between these two.
Many of you may confuse over this topic finding the difference but there lies a solid difference between the two of them, starting with,

1. Latent Heat: The Heat energy required for 1 Kg of solvent to transform itself into vapour state without raise in temperature from its boiling point is called Latent Heat., Usually this is the basic Definition that is explained in engineering classrooms, but while coming to exams time many of us will retain only one thing Latent Heat means Phase change, that's it, even if the one who explored it come before also we wont listen, but in addition to the Phase change in definition there lies another one majestic line, WITHOUT RAISE IN TEMPERATURE , which means Latent heat wont depend upon temperature, and also Temperature is directly proportional to pressure, Latent Heat wont depend upon the Pressure also, Please Note this. 


Also Read:

** How to Calculate Time-Cycle required for Heating/Cooling for a Pharmaceutical Operation?** How to Select a Vacuum Pump for an pharmaceutical Operation?



2. Sensible Heat: The Heat energy required for 1 Kg of solvent to raise its temperature without any phase change is Sensible Heat, So if you can clearly observe this, you can find out the difference between Latent Heat and Sensible Heat, So, this is what we call "EK BALL DHO THUKDA",

 And the Next basic Thing you need to know is what is the difference between a Heat Exchange and a Condenser??

 So, this is a typical question, i can bet that 90% of the Chemical Engineering course relieved students dont know, and even 10% of the working chemical engineers also don't know exactly, because in pharma field everyone will be using these both terms interchangeably, 

 But there lies a major difference between two of them, in a single line every condenser is a heat exchanger, but every heat exchanger is not a condenser, 

The one which exchanges heat can simply called as a Heat Exchanger, just like the reactors, hot water tubs, condensers, distillation columns, etc, 

But whereas coming to a Condenser its main duty is Condensation, so whenever the condensers condensers some vapour's then its duty is over.
Condensers were of many types, shell and tube, double pipe, plate and frame, scrapper type, longitudinal extended surfaces, so being frank we can use a Heat Exchanger as a condenser, but we cant guarantee the efficiency, which is basically depends upon the thermal conductivity of the MOC.





Now i think you got some basic knowledge regarding the aspects of heat transfer, 
So lets get into point directly,

 Let's start our design concept, Once again recollecting, duty of condenser is to take off the latent heat from vapour and condense them, so the load over a condenser will be Latent heat,
Latent Heat, QL = M x Lam


 M - Mass FlowRate of vapour,
Lam - Latent Heat of Vapour.

 So Basically to define the heat transfer of any heat exchanger we will go with the Overall Heat Transfer Coefficient and the Temperature of the fluids, which are in turn correlated by ,
Q = U x A x LMTD.


 Q - Heat Energy, U - Overall Heat Transfer Coefficient, A - Available/Required Heat Transfer Area,
LMTD - Log Mean Temperature Difference.

 So whenever we need to decide the Rate of condensation we need to know the Area of Heat Transfer, Luckily we got the Correlation in terms of heat energy.

 So for the case of condenser duty, 
QL = M x Lam = U x A x LMTD

 So, our Required Heat Transfer Area, 
A = ( M x Lam ) / ( U x LMTD ),

 U value can be considered in between 300 - 450 KCal/Sq.m .hr.°C, this value is not a thumb value, but generated from average of different trials taken while designing the condensers.

 That's it, done.

 But for sure this Area wont suits your requirement, Because we know that the duty of condenser is to condense the vapours, but the condenser donno this fact and even after condensing the vapours it will still reduce the temperature of the condensate, that means it is doing over duty which involves some change in Sensible heat also, so while equating the QL to Q, we need to add QS to QL and then have to equate it to Q. So, now i'll equate mathematically, Dont worry this equation wont involve that much logical mathematics which makes you fear, but just involves simple ones., So now,
Q = QL + QS  , Q = ( M x Lam ) + ( M x C p x dT ),


 To solve this we need to consider same M value for both QL and Qs , and dT should be taken atleast 6°C - 10°C, for getting a better design that suits your requirement. 
So our modified equation for Calculating the Heat Transfer Area is as follows,
A = (( M x C p x dT ) + ( M x Lam )) / ( U x LMTD ).


 Now Say Cheers, It's perfect now.

 For your Convenience i've simulated an excel sheet, use it for accurate values,

Any Queries Please feel free to ask us, We are happy to respond, if you feel great of this then leave some hearty comments here. 

Also Read:

** How To Do Scale up? 

** Batch Failure Investigation by Fault Tree Analysis?

              ** How To Design a Industrial Distillation Column ?



 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


at 12 comments:

Friday, 15 April 2016

[How To] Calculate Time-Cycle required for Heating/Cooling



Hello ,Good day Readers.......!!!
Some of the engineers who were working in technical services will be well aware of the theoretical calculations that were performed to get an brief idea before taking some trials,while coming to the process engineers those who will be focusing on the product launches or technology transfer activities ,need some sound knowledge regarding the heat load calculations, Steam consumption,  pump and its sizing's that are used while going for equipment mapping,and many of us will be going as per thumb rule,which will support upto some extent, and we can take this thumb and apply to every case, Lets say that,





"If somebody is asked a question about what is your condenser capacity needed for a 10KL distillation reactor,I bet within 5Secs,20 sq.m will hit my ears.And Usually while selecting a condenser the major required parameters were the Amount of vapours to be condensed,Nature of vapours to be condensed and the temperature of the vapours to be condensed,Without these all I'l be getting an answer"

So, here my intension is only one thing,and that,it is to mention you guys that Thumb rules are tolerate only upto some extent,it can't be applied to every case,so learn the theoretical one's perfectly,If you want to take heating trial for any heat exchanger then we should be aware of the range of the Temperature in which it lies,so for that we should the mechanical and thermal properties of heat exchanger on which the rate of heat transfer depends, and along with sometimes fouling/scaling factors, Dirt resistance.

Usually the Heat transfer rate strongly depends on the material of construction[MOC] and the thermal conductivity of Material[MOC], Area available for Heat transfer.





The Rate of Cooling/Heating depends on the Utility that we are providing for the operation and the Heat transfer rate.

And whenever we need to calculate the Time-Cycle of heating or Cooling of a mixture, we will have two choices,

1) Calculation based on MOC physical/Thermal properties,
2) Calculation based on the Utility we are using,

So here, you may get a doubt, How can we calculate based on thermal properties, Actually this is a simple way of determining the Time-Cycle, and i'll explain it later in a Separate post.
Recommended Posts
 How To Select a Vacuum Pump ?  
How To Calculate Required Vapor Column Size ?  
How To Do Scale Up ?  
How To Calculate Volume Occupied by Torispherical Dish ?

Coming straight away to the point, Calculating Time-Cycle based on the Utility that we are using:





For this we should be knowing the following data:

1) Temperature of Utility ( Hot water/Hot oil/ Brine/Chilled water/Steam/Liquid Nitrogen ) [T],

2) Initial temperature and Final temperature and Volume of the mixture ( t1, t2, V ),

3) Specific heat capacity of the mixture to be heated ( C p ),

4) Average Overall Heat Transfer Co-efficient of the system ( U ),

5) Heat Transfer Area of the System ( A ).
[How To] Calculate the Heat Transfer Area of a Reactor?

So, Initially we need to calculate the load over the Utility, Whether its a cooling load or heating load,
That Can be calculated by our traditional formula,

Q= M x C p x dT
M  - Mass flowrate - Volumetric Flowrate x Density,
C p - Specific Heat Capacity,
dT  - Temperature difference of the Mixture 
      ( t2-t1) for Heating, ( t1-t2 ) for Cooling.

Now the Heat Load based on the vessel Overall Heat transfer co-efficient to be calculated,

Q= U x A x (dT)ln

U  - Overall Heat Transfer Co-efficient,
A  - Heat Transfer Area,
(dT)ln - Log Mean Temperature Difference - (( T - t1) - ( T - t2 ))/Log[( T - t1 )/( T- t2 )],







So equating the both of the Heat loads, I.e., Supply heat load = Required heat Load.

M x C p x dT  =  U x A x ( dT )ln  =  U x A x (( T - t1)-( T - t2 ))/Log[( T - t1 )/( T- t2 )],

Time Required for Heating/Cooling = [ M x C p x Log(( T - t1 )/( T- t2 )) ] / ( U x A ). 

That's it......... Cheers,

Any Clarifications required, drop a comment, we will be happy to hear from you.......!!!





Also Read:

                

About The Author
Hi! I am Ajay Kumar Kalva, Currently serving as the CEO of this site, a technoholic 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 & Facebook

Pharma Engineering


at 20 comments: