Previous in Forum: Air for Fuel   Next in Forum: Zinc Phosphate Coating On Wire Rod
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
14 comments
Rating: Comments: Nested
happy348
Participant

Join Date: Aug 2013
Posts: 4

Diesel Fuel Combustion

08/11/2013 4:32 AM

C7H13 + 10O2 + 39N2 = x1 CO2 + x2 H2O + x3 N2 + x4 O2 + x5 CO + x6 NOx + x7 CxHy please help me to balance this equation
Register to Reply
Pathfinder Tags: chemical equilibrium dissociation
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#1

Re: diesel fuel combustion

08/11/2013 4:53 AM

I don't think there's enough information for a unique solution. And you forgot the argon (as well as the CO2 on the left side, and also how to use subscripts.)

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#3
In reply to #1

Re: diesel fuel combustion

08/11/2013 7:32 AM

For instance, the solution I like best is:
x1 = x2 = x4 = x5 = x6 = 0
x3 = 39; x4 = 10; x7 = 1
CxHy = C7H13.

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
Usbport
Guru
Engineering Fields - Optical Engineering - Member Engineering Fields - Engineering Physics - Member Engineering Fields - Systems Engineering - Member

Join Date: Apr 2010
Location: Trantor
Posts: 5363
Good Answers: 647
#5
In reply to #3

Re: diesel fuel combustion

08/11/2013 7:59 AM

I prefer CH3CH2OH, usually with a splash of soda water.

__________________
 Whiskey, women -- and astrophysics. Because sometimes a problem can't be solved with just whiskey and women.
Register to Reply Score 1 for Off Topic
energyconversion
Guru

Join Date: Aug 2008
Location: England & Ireland
Posts: 1063
Good Answers: 61
#2

Re: diesel fuel combustion

08/11/2013 6:17 AM

There are 3 hydrocarbons (isomers) with the formula C7H13 - none of which could be regarded as being present in diesel fuel, although there may always be the minutest of quantities present. I don't know where you got this formula from. Diesel is normally regarded as a mixture of hydrocarbons from C8 to C21 - possibly you have been given C14H26 as the "average composition" which has been turned into the empirical formula of C7H13, although I see no point in doing that.

As for balancing the equation - that's your homework. You will only learn by doing it yourself!
Register to Reply
happy348
Participant

Join Date: Aug 2013
Posts: 4
#4
In reply to #2

Re: diesel fuel combustion

08/11/2013 7:56 AM

C8H18 + 12.5O2 + 47N2 = x1 CO2 + x2 H2O + x3 N2

+ x4 O2 + x5 CO + x6 NOx + x7 CxHy

another dissociation formula is

2CO + O2 = 2CO2

NOW what do u say
Register to Reply Score 1 for Off Topic
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#6
In reply to #4

Re: diesel fuel combustion

08/11/2013 10:29 AM

It is trivially easy to generalize from a previous example.

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#10
In reply to #4

Re: diesel fuel combustion

08/12/2013 3:14 AM

The stoichiometry class is just down the corridor, third door on the right. Yes, that's it. Have a splendid day.

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
SolarEagle
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 33392
Good Answers: 1817
#7

Re: Diesel Fuel Combustion

08/11/2013 12:48 PM

I believe that's gasoline....

C7H13 +10:25O2 +38:54N2 ! 7CO2 +6:5H2O+38:54N2

__________________
 All living things seek to control their own destiny....this is the purpose of life
Register to Reply
Original_Macgyver
Guru
Hobbies - CNC - New Member

Join Date: Jul 2013
Location: Lost Wages Nevada
Posts: 1578
Good Answers: 55
#8

Re: Diesel Fuel Combustion

08/11/2013 10:46 PM

The answer is soooo simple!!! All that gibberish = 3. What was so hard about that???????????

__________________
 Though it does seem he frequently has a Swiss Army knife or Leatherman and a roll of duct tape with him.
Register to Reply
austyns1
Active Contributor

Join Date: Jan 2013
Posts: 14
#9

Re: Diesel Fuel Combustion

08/12/2013 12:20 AM

equation is wrong check the number of nitrogen mollecules and repost, cheers
Register to Reply Score 1 for Off Topic
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#11

Re: Diesel Fuel Combustion

08/12/2013 5:40 AM

Nitrogen oxides are a very minor part of what is going on, so they can be ignored with very little effect. Once that is done, assume complete combustion and make the numbers of atoms each side balance-up. It's only simple arithmetic.

How has C7H13 arrived? Hydrocarbons do not usually form with odd numbers of hydrogen atoms. C7H8 would be toluene, for example. C7H14 is a heptene, and C7H16 is a heptane.

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Davesets
Commentator

Join Date: Nov 2010
Posts: 88
Good Answers: 4
#12

Re: Diesel Fuel Combustion

08/12/2013 9:06 PM

C14H26 is not equal to 2(c7h26)
Register to Reply Score 2 for Off Topic
gib
Participant

Join Date: Feb 2013
Location: New Zealand
Posts: 4
Good Answers: 1
#13

Re: Diesel Fuel Combustion

08/12/2013 9:29 PM

Complete or stoichiometric combustion for a diesel engine is where I would start the equation.

The theoretical air to diesel fuel mix is, 14.5 kg of air to 1kg of fuel, however this can vary with diesel engines that can provide excess air to 150% or more to ensure complete combustion. The diesel fuel type or quality can also change this ratio.

eg for perfect stoichiometric mix, C3 H8 +o2 = Co2 + H2o

The N2 is not taken in to count as it doesn't change in the heating inside the engine.
Register to Reply Off Topic (Score 6)
standarded
Guru
United States - Member - Member Hobbies - DIY Welding - New Member

Join Date: Mar 2008
Location: Southeast US of A
Posts: 555
Good Answers: 50
#14

Re: Diesel Fuel Combustion

08/12/2013 10:16 PM

If this is homework, read #14 in the FAQs.

__________________
 Speak softly and carry a big stick.
Register to Reply
Register to Reply
Have a Different Question?
14 comments
Copy to Clipboard

Users who posted comments:

austyns1 (1); Davesets (1); energyconversion (1); gib (1); happy348 (1); Original_Macgyver (1); PWSlack (2); SolarEagle (1); standarded (1); Tornado (3); Usbport (1)

Previous in Forum: Air for Fuel   Next in Forum: Zinc Phosphate Coating On Wire Rod

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Chemical & Material Science:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (82 right now)
Show Members
Advertisement