Discussion
A surrogate liquid hydrocarbon fuel, approximated as C10H12, is being burned in a land-based gas turbine combustor with dry air (79% N2 and 21% O2 by volume). How many moles of dry air are required for the stoichiometric combustion of the surrogate fuel with dry air at atmospheric temperature and pressure?
Answer: A
About 61.9 moles of dry air are needed per mole of fuel.
Balance the complete combustion of C10H12: 10 carbon atoms need 10 O2 to form 10 CO2, and 12 hydrogen atoms form 6 H2O, which needs 3 more O2.
\[ \begin{aligned} &\mathrm{C_{10}H_{12}} + 13\,\mathrm{O_{2}} \\ &\rightarrow 10\,\mathrm{CO_{2}} + 6\,\mathrm{H_{2}O} \end{aligned} \]
Air is 21% oxygen by volume, so
\[ n_{air} = \frac{13}{0.21} = 61.9\ \text{mol} \]
13 is the oxygen alone, not the air. 30.95 is half the correct value, as if the 79/21 ratio were halved, and 10 counts only the carbon.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development