HW3-EAP - 7 H 16 are combusted in 20 excess air how many...

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HOMEWORK 3 (DUE 03/05) 1. Describe the air flow patterns of the 3-zone Hadley cells. Then explain why the trade winds in the northern hemisphere are northeast while in the middle latitude (30 – 60 o ) the winds are southwest. (12%) 2. Explain why low pressure systems are usually accompanied with stormy weather while high pressure systems are associated with sunny weather. (8%) 3. Q 3.4 and Q 3.16 (12%) 4. Q 3.9 and 3.10 (12%) 5. Q 3.14 and Q 3.25 (12%) 6. Q 3.19 and Q 3.20 (12%) 7. What are the dominant wind direction and wind speed presented in the wind rose on the right? What is the possible topography of this wind distribution? (10%) 8. Write the reactions of combustion of propane and ethanol in air, respectively. Remember to balance the reactions. What are the stoichiometric air-fuel ratios? If the air-fuel ratio of the actual mixture is 15, is the combustion under rich or lean conditions for the case of propane and ethanol, respectively? (16%) 9. If 2 moles of heptane (C
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Unformatted text preview: 7 H 16 ) are combusted in 20% excess air, how many moles of O 2 are required in the feed? What is the equivalence ratio in this condition? (16%) 10. What is the atmospheric lifetime of formaldehyde (HCHO) with respect to photodissociation and oxidation by hydroxyl radicals, respectively? What is the overall lifetime due to these two atmospheric effects? The rate constants are: k HCHO+OH = 9.37×10-12 cm 3 molecules-1 s-1 , k HCHO+hv = 0.1 min-1 ; [OH] atmosphere = 10 6 molecules cm 3 (16%) 11. Estimate the temperature required for an afterburner to destroy 99.5% of the toluene contained in an air stream within a residence time of 0.5 s. You may assume that the combustion reaction is first order with a rate constant that obeys the Arrhenius expression. The frequency (pre-exponential) factor and activation energy associated with the thermal oxidation of toluene are 2.28×10 13 s-1 and 56.5 kcal mol-1 , respectively. (16%)...
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