Adiabatic Flame Temperature in Excel

[@isaacalbano407]

Awesome, it saved me in a colleges homework

[@apm]

The example Excel files for this video are posted to apmonitor.com/che263/uploads/Main/flame_temp_exercise.zip

[@thayuranrajaruthnam6832]

Hi Sir, how would you calculate the adiabatic flame temperature when given an inlet temperature of 500 Kelvin?

[@apm]

First calculate how much energy is required to cool the reactants to standard temperature (and pressure).

[@salchicasvoladoras]

From where is this exercise? (Felder Book?) Which number of exercise? Thank you

[@apm]

Elementary Principles of Chemical Processes 3rd Edition by Richard M. Felder and Ronald W. Rousseau - unfortunately, I don't remember the problem number.

[@Orientaliszt]

Thanks for this nice video 1) If one integrate a detailed gas kinetics ( using ChemkinPro or other software) to estimate the flame temperature in these three cases, what will be the difference with your "equilibrium" results ? 2) Very interesting discussion on Adiabatic Temperature dependency with heat capacity correlation 21:56 Indeed, there are many thermodynamic data in NASA format from JANAF or other databases from 300K to 5000K. Is there some sensitivity analysis tools to quantify this dependency in a multi species combustion problem 3) My last question : Are your excel files available ?

[@apm]

+Orientaliszt Thanks for your detailed questions. Here are some responses: 1. It depends on the correlations that the software would use. Sometimes the software will give you an answer but won't share the heat of reaction or heat capacity data. 2. There are many papers that have reported sensitivity studies such as www.turanyi.eu/pdf/39_Turanyi_RESS_1997.pdf I don't know of any that have gone up to 5000K, however. The correlations for heat capacity generally don't extrapolate well to higher temperatures. There are some new methods for sensitivity analysis of systems that are capable for large-scale and sparse dynamic systems (see pubs.acs.org/doi/abs/10.1021/ie201020g and www.mdpi.com/2227-9717/3/3/701/html). If you only need steady state data then the sensitivity calculation is simpler. 3. The lecture materials are posted here: www.et.byu.edu/~tom/classes/273/Classes/ I don't think we have the adiabatic flame temperature workbooks posted, however.

[@Orientaliszt]

+APMonitor.com Hi, Thanks for your answers and the documents. Turanyi paper discuss the sensitivity analysis regarding initial conditions (c0) and rate coefficient constants k for a dynamic kinetics represented by a set of ODE but I think we can extend the approach to the adiabatic flame temperature sensitivity on cp, which is a simple algebraic equation ... Again thank you very much for your help.

[@dzulfiqarabdurrahman3386]

Dear Sir, based on the first ppt (path method) the cp that you chose for methane is applicable only for 0-1200. However, the final value of Tad is in fact exceeding the range mentioned before (2000~). Is it considered as valid or am I missing something? Looking forward to your response, thank you

[@apm]

Methane cp at high temperature isn't a problem if all of the methane reacts to form products CO2 and H2O. We need an accurate cp value for the products.

[@dzulfiqarabdurrahman3386]

@@apm So by any chance, if I calculate for example n-butane air combustion using 0-1500 cp for the products and the result exceeds 2000 then should I also correct the cp according to the result Sir?

[@apm]

@@dzulfiqarabdurrahman3386 JANAF data is a good source for properties at higher temperature.

[@dzulfiqarabdurrahman3386]

@@apm Unfortunately I'm not going to use the JANAF one because my thesis is revolving around Ansys Fluent, so I will use the included value instead

[@HackingDutchman]

Great video, this really speeds up calculation! A question: Can I adapt this correctly to calculate the adiabatic flame temperature of the combustion of a gas mixture with excess air? I have a biogas mixture that consists of 70% CH4 and 30% CO2, I burn it using 1.125 the amount of theoretical air. I use as air, 1 O2 + 3.76 N2. Normal reaction is: 1 CH4 + 2 O2 + 7.52 N2 -> 1 CO2 + 2 H2O + 7.52 N2. Now I add 30% CO2 and 1.125 the amount of theoretical air needed, I multiply everything times 100. My reaction now is: 70 CH4 + 30 CO2 + 157.5 O2 + 592.2 N2 -> 140 H2O + 100 CO2 + 592.2 N2 + 17.5 O2. So, now I also have CO2 in the reactants part and O2 in the products part of the reaction. My adiabatic flame temperature must be lower than with the normal reaction, because the heat of the reaction now also needs to heat the extra CO2 (an extra 30 CO2) and the extra amount of air used (an extra 17.5 O2 and 65.8 N2). When I use the heat of reaction method I get a slightly higher temperature, filling in the values I just talked about, and with the heat of formation method I get a temperature that is around 300 Kelvin lower, that sounds about right. Can I just use the heat of formation method for this calculation, with extra CO2 and air, or do I need to alter the formula itself to be usable in my situation? Or do I need to use a totally different approach in my situation to calculate the adiabatic flame temperature?

[@apm]

Yes, you can use this same calculation but the excess O2 is also treated as an inert, just like the Nitrogen.

[@samehmohamed4976]

how did you put the enthalpies of different temperatures in the excel sheet?

[@apm]

They are correlations from JANAF.

[@ridakhan9334]

Hi sir. In my question methane is burning in 20% excess air. what would it be in that case

[@apm]

The excess air is considered to be inert for purposes of flame temperature calculation.

[@ridakhan9334]

@@apm you have used solver but my teacher said to use goal seek so how will it be done through goal seek

[@ossoss641]

Great video, Me and a friend are working on a project where we currently need to find the adiabatic Flame temperature of a reaction, we were just wondering how you went about getting the CsubP terms from JANNAF or from Felder

[@apm]

+OSS OSS Felder Cp correlations are in Appendix B. JANNAF correlations are better for high temperatures. JANNAF are publicly available but I don't have a link (maybe Google it). DIPPR correlations are also available for over 2000 compounds. Felder is probably sufficient for homework problems.

[@abdulzaman3100]

Problem 4] Please complete the yellow cells to calculate the flame temperature of Hexane (until the checking value in C3 cell becomes 1)

[@abdulzaman3100]

How can i solve this problem if carbon no is 1

[@soggiesfreaz]

can you help me finding the adiabatic flame temperature of HTPB with oxygen?

[@apm]

Sorry, I can't typically help with specific applications. Post something here if you figure out a solution.

[@KoobztheShawk]

Prashant this is a good question. If you provide the products, it can be answered

[@leonardosoto5669]

why the reaction forms water vapor even if water is liquid at 1 bar and 25 C? is the only thing i CANT understand

[@apm]

You just do the energy conversion calculation at standard conditions and then use sensible heating to determine the final temperature.

[@MrAmgadHasan]

Because the products mixture is at 1 bar BUT the partial pressure of water is less than 1 bar. Remember that the partial pressure of a component equals its mole fraction multiplied by the mixture pressure (1 bar). If you do the calculation, you will find that the partial pressure of water is less than three saturation pressure so it exists as a vapour.

[@nelitk]

what is the name of the book of tables?

[@apm]

It is first author Felder as introduction to chemical Engineering

[@kayhankurul9648]

Nice explanation. I'm afraid that Methane aidabatic flame temp. 2226 K. The calculation says 2345 K.

[@apm]

The heat capacity or other information may need to be updated. Thanks for the comment.

[@kayhankurul9648]

@@apm I used enthalpy values to calculate A.F.T of methane. It is totally different from both of the calculations.

[@muhammadjamal573]

Write a program to study the effect of the percentage of theoretical air on the adiabatic flame temperature for a (variable) hydrocarbon fuel. Assume reactants enter the combustion chamber at 25◦C and complete combustion. Use constant specific heat of the various products of combustion, and let the fuel composition and its enthalpy of formation be program inputs.

[@apm]

The Excel sheet in this video should be able to do this calculation for you. That sounds like a great homework problem.

[@muhammadjamal573]

I am having a trouble in solving this kindly give me aa sample to find this .. I'll b every thankfull to you

[@apm]

The example files in this video are posted to apmonitor.com/che263/uploads/Main/flame_temp_exercise.zip

[@juancabrera-ru9jx]

Question When showing your final Excel document, your "In" is in Celcius and your out is in Kelvin although that line of the chart says it should be in celsius. Is this still correct? Thanks for the great video

[@apm]

I normally like to work in Kelvin but in this case, the heat capacity correlations at 9:48 are in Celsius. I use a couple different Excel sheets in this document. Could you point to which one you are referencing? I've checked these sheets many times but there is a chance that I made a mistake.

[@juancabrera-ru9jx]

Example 2-Adiabatic flame T Example.xlsx 25.08 min, on the line T(C) line on chart OUT. Is that temperature meant to be in celsius or kelvin.

[@apm]

juan cabrera great catch! Yes, cell C23 at 25:08 should be T (K). The JANNAF correlations use K rather than degC like the Felder book. The calculations are correct, just a bad heading.

[@juancabrera-ru9jx]

Thank you so much, again great video.

[@oumaymajalali7659]

hi please can u send this excel sheet

[@apm]

Sorry, I didn't keep a copy.

[@umair8474]

Hellow sir!!! Can you plz solve this for me, " An article that appeared in the Reno Gazette- Journal on May 18, 1992, quotes an inventor as saying that he has turned water into motor vehicle fuel in a breakthrough that would increase engine efficiency, save gasoline, and reduce smog. There is also a picture of a car that the inventor has modified to run on half water and half gasoline. The inventor claims that sparks from catalytic poles in the converted engine break down the water into oxygen and hydrogen, which is burned with the gasoline. He adds that hydrogen has a higher energy density than carbon and the high-energy density enables one to get more power. The inventor states that the fuel efficiency of his car increased from 20 mpg (miles per gallon) to more than 50 mpg of gasoline as a result of conversion and notes that the conversion has sharply reduced emissions of hydrocarbons, carbon monoxide, and other exhaust pollutants. Evaluate the claims made by the inventor, and write a report that is to be submitted to a group of investors who are considering financing this invention."

[@apm]

Here is my report to the investors: Adding water to gasoline is a really bad idea unless you are a shady gasoline service station.

[@umair8474]

Excuse me sir it's not practically done it's just numerical which is the problem#15.183 from thermodynamics 7th edition by Claus Borgnakke but I can't find the solution, if you have then plz send me!!!

[@umair8474]

Plz sir solve this or just give me the layout????

[@abdelkaderhemaizia6063]

hello sir @t can you share with us the Exel files really we need it... thank you

[@apm]

Sorry, I haven't posted the Excel sheet but here are some heat capacity tables: www.et.byu.edu/~tom/classes/273/273.html

[@elinasalaszevallos1862]

@@apm but from what source is this data?

[@apm]

@@elinasalaszevallos1862 it is from the JANNAF tables

[@elinasalaszevallos1862]

Excuse me, I did my exercise just like the one in your example, but my teacher told me the following: You do not indicate in which range the indicated coefficients are valid. Could you help me with that?

[@apm]

@@elinasalaszevallos1862 DIPPR or JANNAF coefficients have temperature ranges where they are valid. For example, JANNAF has low temperature =1500 degC coefficients.