Hii .....!! Good day to all my visitors.....!!!
Recently i've received some queries asking about addition time of key reagents and some queries related to Reaction calorimetry studies.
And to all, i can say there lies a calculation for addition time, which is based on the evaluation of RC1e data.
But before entering into the calculation, all those who are reading should enter my trans, so that it will become some what easy for me, or else there shall be lot of evolving queries.
Lets start with some below,
What is a key reagent ?
A key reagent is some solution or a compound that involves itself in reaction giving out desired product, without its presence the reaction is incomplete. Key reagents doesn't includes catalyst's.
What does RC abbreviate ?
RC Stands for Reaction calorimetry.
What can we get from RC study ?
RC study gives the reaction rate, heat of reaction, adiabatic temperature rise during addition/reaction, Nature of reaction, Maximum Heat flow.
What does Adiabatic Temperature raise refers to ?
Adiabatic temperature rise refers to the raise in temperature during a chemical reaction where energy is liberated and the liberated energy can't be exchanged with environment / any source.
Lets begin the show,
Usually RC1e data shall be generated form an Isoperibolic(System where the external temperature shall be maintained same) system, Have a look at the isoperibolic system,
There will be sensors to display the temperature raise during dosing of reagents & volume measurement chambers to measure the gas evolution rates.
Now i'll go down the calculation part and how to correlate the data to plant mapping and to be proactive.
Let's suppose there is a reaction between two reagents( A is KSM & B is a KRM), Methanol be the reaction medium, and C be the catalyst.
Dead Basic reaction 
The same process shall be executed in the RC1e chamber and
1. While dosing the beast B the temperature raise shall be recorded(It will be adiabatic temperature raise T), and
2. The energy liberated shall also be evaluated(Heat of reaction Hr),
3. After completion of addition the energy liberated shall be evaluated, so that the accumulated energy/percentage of accumulation shall be evaluated.
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Based on the data generated, we can calculate the MTSR,
Now you guys may get a doubt, that what is MTSR ?
MTSR means Maximum temperature attainable by the synthesis reaction, it exactly means that in a worst case it is the maximum temperature that a reaction can make up.
MTSR = (Operating temp.) + (Adiabatic temp. raise x % Accumulation).
This MTSR should be less than our reaction mass decomposition temperature,
Now again you may get a doubt, what is this reaction mass decomposition temperature and where the hell can we get it....!!!
So for those, we can get it from DSC study(Differential Scanning Calorimetry),
I'll explain you about DSC study in detail in my next post.
Coming to our case study,
Let the energy liberated during dosing the beast B be 1000 Kj /Kg of KSM.
% accumulation be 30%, and the adiabatic temperature raise be 49 C.
So now MTSR will be : 50 + (49 x 0.3) = 64.7 ⁰C
Here 50⁰C is our reaction temperature.
So, now we need to evaluate the total energy liberation and need to correlate to plant scale.
So total heat liberated as per RC1e study is 1000 Kj/Kg.
Lets suppose the batch size is 150 Kgs,
So total energy liberated for the subject batch size is 150 x 1000 = 150000 Kj.
And now we need to evaluate whether the addition is feasible in plant scale or not,
And if its feasible, how much time will it take in the available manufacturing equipment.
Usually there will be some additions which will hold a case where the addition need to be done in some specified time,
If that's the case then we need to calculate the total time and then based on trial and error we need to select the utility which shall be used for carrying out the operation,
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As per the available lab study, the addition /dosing of beast B need to be done in 2 hours,
And now we need to check the feasibility of the reaction w.r.t. time,
Lets say the reactor is having RT as utility in jacket,
then we need to stick to the basic equation, i.e., M x Cp x dT = U x A x LMTD.
and time of addition shall be calculated based on the below formula,
t = ( M x Cp x dT ) / ( U x A x LMTD ).
M is the reaction mass volume at the final stage of addition / dosing,
Cp is the specific heat of the reaction mass  we can get it from RC1e report,
dT is the temperature difference available to perform the operation,
U is the overall heat transfer coefficient,
A is the available heat transfer area,
LMTD is calculated based on the utility and the reaction mass temperatures.
Below is the calculation with RT as utility in jacket,
Heat liberation per Kg of KSM

1290

Kj / Kg

Batch Size

150

Kgs

Total heat liberation per batch

193500

Kj

TR required per 150 Kgs batch size

15.31

TR

Overall Heat Transfer Coefficient

100

Kcal/ hr.Sq.m. K

Reactor Capacity

10000

Lts

Reaction mass volume

4500

Lts

Average density of Rxn. mass

0.9

Kg/L

Total Heat transfer area

19.74

m^{2}

Approx Jacket area

8.88

m^{2}

Coolant in

25

^{0}C

Coolant out

30

^{0}C

Rxn. Mass temperature initial

45

^{0}C

Rxn. Mass temperature Final

55

^{0}C

d T_{1}

15

^{0}C

d T_{2}

30

^{0}C

LMTD

21.64

^{0}C

Heat Capacity

19223

Kcal/hr

Total time for beast B addition

2.87

hr

So here the time of addition is 2.87 hours, which is not acceptable, hence we need to evaluate with a different utility with better efficiency,
Lets try with Chilled water with an inlet temp of 12 ^{0}C,
Below is the calculation,
Heat liberation per Kg of KSM

1290

Kj / Kg

Batch Size

150

Kgs

Total heat liberation per batch

193500

Kj

TR required per 150 Kgs batch size

15.31

TR

Overall Heat Transfer Coefficient

100

Kcal/ hr.Sq.m. K

Reactor Capacity

10000

Lts

Reaction mass volume

4500

Lts

Average density of Rxn mass

0.9

Kg/L

Total Heat transfer area

19.74

m^{2}

Aprox Jacket area

8.88

m^{2}

Coolent in

12

0C

Coolent out

18

0C

Rxn. Mass temerature initial

45

0C

Rxn. Mass temerature Final

55

0C

d T_{1}

27

0C

d T_{2}

43

0C

LMTD

34.38

0C

Heat Capacity

30541

Kcal/hr

Total time for beast B addition

1.8

hr

So here it the addition time came around 1.80 hours as per calculation but it may vary based on the practical approach.
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Hence its better to try out with an other utility with extra efficiency,
Lets go with chilled brine having source temperature of 5 ^{0}C
Below is the calculation,
Heat liberation per Kg of KSM

1290

Kj / Kg

Batch Size

150

Kgs

Total heat liberation per batch

193500

Kj

TR required per 150 Kgs batch size

15.31

TR

Overall Heat Transfer Coefficient

100

Kcal/ hr.Sq.m. K

Reactor Capacity

10000

Lts

Reaction mass volume

4500

Lts

Average density of Rxn mass

0.9

Kg/L

Total Heat transfer area

19.74

m^{2}

Aprox Jacket area

8.88

m^{2}

Coolent in

5

0C

Coolent out

0

0C

Rxn. Mass temerature initial

45

0C

Rxn. Mass temerature Final

55

0C

d T_{1}

45

0C

d T_{2}

60

0C

LMTD

52.14

0C

Heat Capacity

46317

Kcal/hr

Total time for beast B addition

1.19

hr

As per the calculation, the addition time came around 1.20 hours, which is comfortable.
Hence based on the trail and error evaluation, it is found that the reaction between A & B can be carried out with chilled brine utility which is at 5 ^{0}C.
That's it.......!!
Now let's think back about situation and the sudden surprises that we may face without RC1e data ðŸ˜‚ðŸ˜‚ðŸ˜‚ðŸ˜‚.
Hope now everyone who gone through the post should have got something about evaluating the RC1e data,
If nay queries feel free to comment / message.
Comments are most appreciated.
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Good information ajay.......
ReplyDeleteSir how would you find out that "% accumulation be 30%"??? And in three consecutive table heat capacity of reaction mass changes how it is possible??Do you mean to say that changes in utility condition heat capacity of rm chsnges???
ReplyDeleteSir unit of heat capacity is kcal/kgK...But here it been written as kcal/hr .. so here heat capacity means rate of heat transfer??
ReplyDeleteHiii Pratim,
DeleteWhat you said is correct, but there i mean considered heat transfer rate through heat transfer area.
Regards,
AJAY K
the post is really nice.i have a question that how would you find out that "% accumulation be 30%"? Further it would be great if u post about Flow reactor used in Pharma industry. highly appreciate your response on the same.
ReplyDeleteHey Rajeev,
DeleteI've considered accumulation as 30%, but it may vary, it may be 80% or it may be 10% or it may be 0%, thats just an assumption,
In an adiabatic system, it can be calculated as ratio to energy liberated after complete dosing to total energy liberated during or after dosing of reagent.
Regards,
AJAY K
Hello Process Engineer's from API pharmaceutical background:
ReplyDelete1.Elucidate the site solvent loss calculation across the manufacturing site either using physical data or SAP data.
2. What are the standard practices following at pharma industry for solvent loss?
3. How to minimise the solvent loss without altering the existing process?
Thanks,
Kanaka Raju M,
Bangalore.
Email: m.s.kanakaraju@gmail.com
Dear Raju,
DeleteMessage me through the available contact me page, so that i may help you.
Best Regards,
AJAY K
Nice post..thank you very much..happy to see post on flow reactor in pharma industry.
ReplyDeleteDear Ajay
ReplyDeleteRequesing to please post DSC studies details
Regards
Seetharamaiah
Good one. Can u please forward the excel sheet.
ReplyDeleteMy Email: satyammishra22@gmail.com
RC1e data can't be generated from adiabatic system, Generally users prefer Either Isothermal mode or Isoperibolic mode. RC1e will give data of the desired reaction where as ARC/DSC will provide the data of the undesired reaction and that's reason ARC & DSC instruments are so called adiabatic calorimeters.
ReplyDeleteThanks Raghu for correcting, modified the post
DeleteRC shall be used to monitor the desired reaction, where as ARC,DSC shall be used to find the decomposition range, so that the probability for safe reaction can be evaluated.
Regards,
AJAY K
Energy liberated during addition of Beast B be 1000 kj. This 1000kj energy was calculated using formula or wheather it is from RC data / graph.
ReplyDeleteRegards
Harikrishna
Hiii Hari,
DeleteThat we need to take from RC1 report. In the post, i've just assumed.
Regards,
AJAY K