Energy Balance with Reaction

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Energy Balance with Reaction

Рет қаралды 29,495

9 жыл бұрын

Two methods are shown for computing a change in enthalpy when there are reactions. The first method, path approach, is shown for a simple A to 2B reaction. The second method, heat of formation approach, is shown for ammonia oxidation in a two reaction sequence.

Пікірлер: 47

@sonuaryan5287 2 жыл бұрын

It's actually help in my career of Mathematical Modeling with Chemical Equations

@UliSwag 4 жыл бұрын

Thank you for this video! It was very helpful. I appreciate what you are doing!

@xOxAdnanxOx 2 жыл бұрын

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!

@apm 2 жыл бұрын

Here is the derivation of the dependency of heat capacity on the pressure: kzfaq.info/get/bejne/sNGAobKIt9bXlX0.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.

@ankitsingh1760 2 жыл бұрын

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?

@apm 2 жыл бұрын

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.

@markovanstein 2 жыл бұрын

on the second problem, what if we have different pressures entering and exiting? what would it change in the calculations?

@apm 2 жыл бұрын

The reaction typically occurs at the exit pressure. The different inlet pressure affects the number of moles entering.

@abdullahal-maktoomi7487 2 жыл бұрын

that was very useful so thank you very much

@salchicasvoladoras 3 ай бұрын

From which book are the problems

@apm 2 ай бұрын

Elementary Principles of Chemical Processes 3rd Edition by Richard M. Felder and Ronald W. Rousseau

@almassyafei6677 2 жыл бұрын

hello sir, is it still can be applied to a single reaction ?

@apm 2 жыл бұрын

Yes

@gopikrishna177 4 жыл бұрын

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

@apm 4 жыл бұрын

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.

@apm 4 жыл бұрын

For liquid systems, the enthalpy change with pressure is generally insignificant compared to the heat of reaction.

@gopikrishna177 4 жыл бұрын

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.

@gopikrishna177 4 жыл бұрын

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.

@ketanpatil14 4 жыл бұрын

@@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!!

@azimramlan9778 6 жыл бұрын

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?

@apm 6 жыл бұрын

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.

@henriquedavidjoaopabis7108 4 жыл бұрын

Why carbon if there´s not any substance with it?

@apm 4 жыл бұрын

Elemental carbon is the zero energy state for that element when calculating the heat of formation.

@ciweilee5129 6 жыл бұрын

Hi can i have the file with those Cp coefficient?

@apm 6 жыл бұрын

A heat capacity table is posted here along with the presentation material: www.et.byu.edu/~tom/classes/273/273.html

@ciweilee5129 6 жыл бұрын

Thanks very much sir

@eshanbund3588 3 жыл бұрын

Hello could you make the excel you have available? if possible?

@apm 3 жыл бұрын

Unfortunately, I don't have the sheet available online.

@qeedahnordin277 5 жыл бұрын

How to do energy balance without reaction?

@apm 5 жыл бұрын

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

@nanangmuhammad2067 5 жыл бұрын

@@apm right, that is just using heat capacity and mol, make them multiple calculation... mol x H, is like that?

@nanangmuhammad2067 5 жыл бұрын

@@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....

@qeedahnordin277 5 жыл бұрын

Whats the title of the book?

@apm 5 жыл бұрын

Richard M. Felder and 1 more Elementary Principles of Chemical Processes, 3rd Edition 2005

@qeedahnordin277 5 жыл бұрын

thank you very much

@qeedahnordin277 5 жыл бұрын

hello sir can i know which book for the heat capacity youre refering to