As air is composed of mixture of gases nitrogen, oxygen and carbon dioxide. The
ID: 700596 • Letter: A
Question
As air is composed of mixture of gases nitrogen, oxygen and carbon dioxide. The local concentration of nitrogen and oxygen can be calculated in the mole fraction.
Total no of moles of products = 14 + 15 + 4.5 + 97.76 = 131.26
Mole fraction of oxygen = 4.5 / 131.26 = 0.034
Mole fraction of nitrogen = 97.76 / 131.26 = 0.745
We have to calculate the equilibrium concentration of atomic oxygen O in the given reaction
O2 -----------> O + O
Since at equilibrium O2 is changing into O and amount of oxygen present is 0.034 as calculated above. So every mole of O2 breaks we get one mole of O. So the change in concentration is equal to change in concentration of O2.So the equilibrium concentration of atomic oxygen is equal to 0.034.
3) d[NO]/dt = 2k1 [O2]eq [N2]eq
d[NO]/dt = 2 X 7.50 X 1013 exp [-27,750 K/T] X 0.034 X 0.745
d[NO]/dt = 0.379 X 1013 exp [-27,750 K/T]
d[NO]/dt = 3.79 X 1012 exp [-27,750 X 20/1800]
d[NO]/dt = 3.79 X 1012 exp-308.33
d[NO]/dt = 3.79 X 1012 X 1.24
d[NO]/dt = 4.69 X 1012
Explanation / Answer
Combustion chemical kinetics
5. In the secondary region of a gas turbine combustor, the combustion gas is at a local temperature and pressure of 1,800 K and 20 atm respectively, following the combustion reaction C14H30 + 26.00, +97.76N, 14CO2 + 15H,0 + 450, + 97.76N, (i) On the basis of the above reaction equation, determine the local concentration of Nz and O2 in the products, assuming all product gases obey the ideal gas law, (ii) Considering the equilibrium reaction O2 0 + 0 in the above conditions, estimate the equilibrium concentration of atomic oxygen O in the secondary region for T= 1,800 K, p = 20 atm. Ignore all other equilibrium reactions. i The extended Zeldovich mechanism predicts that the rate of formation of NO concentration is given by dt where k 7.50 x 1013 exp[-27,750 KJT] cm/mole.s. If the combustion gas products in (a) above have a residence time in the secondary region of 0.006 s, use your solutions in (a) above to determine the normalised NO concentration formed in the million (ppm)Related Questions
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