Dear sir: do the same technique apply to calculate the heat of formation for surface reaction? Where the two reactants (one is gas and another is metal surface), both at different temperatures, react and form metal oxide and residual gas as products. In this reaction, what would be the typical temperatures of products?
The final temperature would likely be different because the surface would conduct away the heat. Multi-phase problems such as solid-gas are more complicated than this simple problem.
thank you for such amazing presentation on this topic. I got a question, so these Cp values with their coefficients are used when dealing with conditions that satisfy ideal gas behavior but the other two stream conditions in the example, air & outlet, were at non ideal conditions why it is still applied? I wonder if I can use this method in a process with conditions at 20 bar and 900C plz help thank you!
Here is the derivation of the dependency of heat capacity on the pressure: ruclips.net/video/zkPnOWRpseI/видео.html Most correlations for heat capacity also give a temperature range over which they are valid. You may need to switch to a higher temperature range if it is above the accuracy limit for temperature.
Sir what will be effect of pressure on the cp coefficients.sir I have ok one doubt.The coefficients u are considered are only valid for low pressures but u r pressure is 8 bar it's not low.what will be the effect of pressure in the heat of recation
Most heats of reaction are reported at 1 atm. If you have a reaction at high pressure for a gas then you need to bring the reactants down to 1 atm and then back to the high pressure for the products. You can use ΔH = ΔU + Δ(PV) or for an ideal gas ΔH = ΔU + Δ(nRT) where Δn is the change in moles of the gas components.
I have the equation for finding the heat of the reaction for other than 25°C,same way as u said by bringing back the reactants to 25°C and adding heat of formation and sensible heat we will get the heat of formation.sir can u provide me with equations how to find heat of formation for different pressures.
Exactly I can't get it how to bring back to 1atm and do the calculations.sir,plz provide me equations for solving those type of problems. Thank you sir.
@@gopikrishna177 brother if u have got answer of this then kindly share it to me because I've also same problem and I don't know how to calculate ∆H with pressure other than 1 atm My mail id: keton21033@gmail.com Do msg if u found any solution on this it will be great help!!
i know im late, but if the inlet feed has multiple species(ie: air contains co2 and other), is it still the same calculation for Q? do i need to consider other stuff as well?
You'd just need to add any additional species as inputs or outputs. In the case of CO2, it will act as an inert so only sensible heating of CO2 will affect the Q value and the final temperature.
You can just set the heat of reaction term to zero. Here is some additional help on balance equations: apmonitor.com/pdc/index.php/Main/PhysicsBasedModels
Dear sir: do the same technique apply to calculate the heat of formation for surface reaction? Where the two reactants (one is gas and another is metal surface), both at different temperatures, react and form metal oxide and residual gas as products. In this reaction, what would be the typical temperatures of products?
The final temperature would likely be different because the surface would conduct away the heat. Multi-phase problems such as solid-gas are more complicated than this simple problem.
on the second problem, what if we have different pressures entering and exiting? what would it change in the calculations?
The reaction typically occurs at the exit pressure. The different inlet pressure affects the number of moles entering.
thank you for such amazing presentation on this topic. I got a question, so these Cp values with their coefficients are used when dealing with conditions that satisfy ideal gas behavior but the other two stream conditions in the example, air & outlet, were at non ideal conditions why it is still applied? I wonder if I can use this method in a process with conditions at 20 bar and 900C plz help thank you!
Here is the derivation of the dependency of heat capacity on the pressure: ruclips.net/video/zkPnOWRpseI/видео.html Most correlations for heat capacity also give a temperature range over which they are valid. You may need to switch to a higher temperature range if it is above the accuracy limit for temperature.
hello sir, is it still can be applied to a single reaction ?
Yes
It's actually help in my career of Mathematical Modeling with Chemical Equations
From which book are the problems
Elementary Principles of Chemical Processes 3rd Edition by Richard M. Felder and Ronald W. Rousseau
Sir what will be effect of pressure on the cp coefficients.sir I have ok one doubt.The coefficients u are considered are only valid for low pressures but u r pressure is 8 bar it's not low.what will be the effect of pressure in the heat of recation
Most heats of reaction are reported at 1 atm. If you have a reaction at high pressure for a gas then you need to bring the reactants down to 1 atm and then back to the high pressure for the products. You can use ΔH = ΔU + Δ(PV) or for an ideal gas ΔH = ΔU + Δ(nRT) where Δn is the change in moles of the gas components.
For liquid systems, the enthalpy change with pressure is generally insignificant compared to the heat of reaction.
I have the equation for finding the heat of the reaction for other than 25°C,same way as u said by bringing back the reactants to 25°C and adding heat of formation and sensible heat we will get the heat of formation.sir can u provide me with equations how to find heat of formation for different pressures.
Exactly I can't get it how to bring back to 1atm and do the calculations.sir,plz provide me equations for solving those type of problems.
Thank you sir.
@@gopikrishna177 brother if u have got answer of this then kindly share it to me because I've also same problem and I don't know how to calculate ∆H with pressure other than 1 atm
My mail id: keton21033@gmail.com
Do msg if u found any solution on this it will be great help!!
Hi can i have the file with those Cp coefficient?
A heat capacity table is posted here along with the presentation material: www.et.byu.edu/~tom/classes/273/273.html
Thanks very much sir
i know im late, but if the inlet feed has multiple species(ie: air contains co2 and other), is it still the same calculation for Q? do i need to consider other stuff as well?
You'd just need to add any additional species as inputs or outputs. In the case of CO2, it will act as an inert so only sensible heating of CO2 will affect the Q value and the final temperature.
Why carbon if there´s not any substance with it?
Elemental carbon is the zero energy state for that element when calculating the heat of formation.
Thank you for this video! It was very helpful. I appreciate what you are doing!
Whats the title of the book?
Richard M. Felder and 1 more
Elementary Principles of Chemical Processes, 3rd Edition 2005
thank you very much
hello sir can i know which book for the heat capacity youre refering to
There are heat capacity tables in the Felder book. The JANNAF tables may be online.
sir.. how to find cp which are not available on the table like cyclohexylamine and nitrobenzene.
How to do energy balance without reaction?
You can just set the heat of reaction term to zero. Here is some additional help on balance equations: apmonitor.com/pdc/index.php/Main/PhysicsBasedModels
@@apm right, that is just using heat capacity and mol, make them multiple calculation... mol x H, is like that?
@@apm hello Mr. Can you help me.. i have problem to calculation about heat ballance on evaporator? I just want to ask you.. please help me....
that was very useful so thank you very much
can you send me this powerpoint slide?
+Khalid Iqbal, slides are available here www.et.byu.edu/~tom/classes/273/Classes/
Thank you so much Sir.. Will remain grateful for this kind cooperation. Stay Blessed
Hello could you make the excel you have available? if possible?
Unfortunately, I don't have the sheet available online.