In combustion of CO in moist air, the following reaction mechanism describes
the initial stages of the reaction,
CO + O2
→ CO2 + O 
O + H2
O → OH + OH [11b]
OH + CO → CO2 + H 
H + O2
→ OH + O 
Assuming that O and H are in quasi-steady-state, derive an expression for [OH]
as a function of time in terms of [CO] and [O2] and the rate coefficients for the
above reactions. During the initial stages of the reaction, assume that T ≈ constant
and [CO] and [O2] ≈ constant and equal to the initial concentrations. Using this
result, write an expression for d[CO2]/dt. Is the reaction explosive (i.e., does the
rate of formation of products increase exponentially in time)? In the absence of
water vapor, is the reaction explosive? I.e., there are no [11b], ,  reactions.
You only have  reaction.
- For a stoichiometric CH4-air flame at 1 atm, the flashback velocity gradient is
400 s-1, and the flame thickness is 1 mm. For, this problem, the answer does not
have to be accurate. You can utilize scaling relations between properties.
a) Estimate the laminar flame speed of this mixture in cm/s.
b) What is the approximate burner diameter to prevent flashback?
c) If the overall order of the one-step global reaction is 1.3 (i.e., n = 1.3), what is
the critical flashback velocity gradient at 10 atm?
d) If the maximum turndown ratio of a stoichiometric CH4-air flame at 1 atm is
5, what is the blow-off velocity gradient at 1 atm?