when you say you take the basis as ethanol, we consider all the equations based on ethanol balance right? and even if we were to have taken water too, the relation of the sum of mole fractions being one would have then kept the DOF the exact same right? Final question could you suggest a book for learning process modelling and simulation please? Thankyou.
So for the overall balance we only consider streams that are leaving the units or systems(overall products) and not entering elsewhere?..which is why n1 and y1M and y3M is not considered as their streams are still inputs in unit1 and unit2 respectively
Yes thats correct, the overall balance only looks at what enters the system (deemed as "fresh") and what leaves the system entierly (not including any recycles, since they will be returned to the process). Thanks for watching!
You can make reference to component/stream relationships either overall or on a per unit basis. The reason we did the n2 = n4 in the overall is because stream 2 and 4 both leave the system completely and we can formulate a known relationship. One thing to note is that once a relationship is established, you can't "over-relate" otherwise we create contradictions and our DOF will not equal to 0. I hope this helps!
Grer video but i havr a question, in the 2 unit system when taking the number of knowns in the overall balance, why isnt it 3 instead of 2, i mean there's 100 moles, 10 moles and 70 moles...
Thank you for your kind words! In the second example, with the overall balance there is three knowns, it might be because it has been written as "2 balances, n2 = n4" this means 2 balances and 1 relationship between the top products i.e. a total of 3 knowns. I hope this helps, and thanks again for watching!
We can make this assumption when we consider the overall balance that is to say that both n2 and n4 can be grouped to represent the "top product" leaving the entire system. Thank you for asking this question as I should have explained this better. I hope this helps, and thanks again for watching!
To identify the number of "known's " this is dependent upon the information provided to you. Typically flowrates, stream compositions, conversions, recovery requirements, recycle ratios, relationships between compounds or streams, are the best starting point. For each one (ensuring there is no duplicates) you simply add them all up to give you the total amount. I hope this helps!
This instructor really knows his stuff, very good tutorial and will be sharing with my friends!!
Awesome, thank you!
A very clear and good explanation! Great work 👏
Thank you, much appreciated.
Excellent tutorial, has helped me so much, thank you for your channel!
You are so welcome!
WOW!!! How clear is his explanation!
Thank you for your kind words
Top class video, very helpful sir!
Glad it was helpful!
Very informative Dr, clear and easy to follow, looking forward to enrolling onto your courses #chemicalengineering #thechemengstudent
Thank you for your kind words, looking forward to welcoming you to our community!
This was a really clear explanation greetings from Texas! Who else is from the US here guys?
Thank you for your kind words, so good to hear from more international students, thank you for your support.
A very good tutorial yet again sir👍
Glad you liked it!
when you say you take the basis as ethanol, we consider all the equations based on ethanol balance right? and even if we were to have taken water too, the relation of the sum of mole fractions being one would have then kept the DOF the exact same right? Final question could you suggest a book for learning process modelling and simulation please? Thankyou.
So for the overall balance we only consider streams that are leaving the units or systems(overall products) and not entering elsewhere?..which is why n1 and y1M and y3M is not considered as their streams are still inputs in unit1 and unit2 respectively
Yes thats correct, the overall balance only looks at what enters the system (deemed as "fresh") and what leaves the system entierly (not including any recycles, since they will be returned to the process). Thanks for watching!
Also that do we consider relations only in the overall balance as for DOF of unit 2 you did not include the relation of n4
You can make reference to component/stream relationships either overall or on a per unit basis. The reason we did the n2 = n4 in the overall is because stream 2 and 4 both leave the system completely and we can formulate a known relationship. One thing to note is that once a relationship is established, you can't "over-relate" otherwise we create contradictions and our DOF will not equal to 0. I hope this helps!
How do I know the number of knowns? In those 2 unit system
Grer video but i havr a question, in the 2 unit system when taking the number of knowns in the overall balance, why isnt it 3 instead of 2, i mean there's 100 moles, 10 moles and 70 moles...
Thank you for your kind words! In the second example, with the overall balance there is three knowns, it might be because it has been written as "2 balances, n2 = n4" this means 2 balances and 1 relationship between the top products i.e. a total of 3 knowns. I hope this helps, and thanks again for watching!
can you please do the material balance
Sure, is it the systems shown in this video or just in general a material balance system?
Why n2 is same as n4
We can make this assumption when we consider the overall balance that is to say that both n2 and n4 can be grouped to represent the "top product" leaving the entire system. Thank you for asking this question as I should have explained this better. I hope this helps, and thanks again for watching!
If only you were my professor 😭
Thank you for your kind words! If you need any further help/assistance, please don't hesitate to contact me.
How do I know how many known?
To identify the number of "known's " this is dependent upon the information provided to you. Typically flowrates, stream compositions, conversions, recovery requirements, recycle ratios, relationships between compounds or streams, are the best starting point. For each one (ensuring there is no duplicates) you simply add them all up to give you the total amount. I hope this helps!
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