In 1981, the U.S. government put forth the following plan for automobile manufacturers to reduce emissions from
Question:
In 1981, the U.S. government put forth the following plan for automobile manufacturers to reduce emissions from automobiles over the next few years.
All values are in grams per mile. An automobile emitting 3.74 lbm of CO and 0.37 lb m of NO on a journey of 1000 miles would meet the current government requirements.
To remove oxides of nitrogen (assumed to be NO) from automobile exhaust, a scheme has been proposed that uses unburned carbon monoxide (CO) in the exhaust to reduce the NO over a solid catalyst, according to the reaction
CO+NO→catalystProducts (N2,CO2)
Experimental data for a particular solid catalyst indicate that the reaction rate can be well represented over a large range of temperatures by
−rN′=kPNPC(1+K1PN+K2PC)2(P10-9.1) wherePN=gas-phase partial pressure of NOPC=gas-phase partial pressure of COk,K1,K2=coefficients depending only on temperature
a. Propose an adsorption–surface reaction–desorption mechanism and rate-limiting step that are consistent with the experimentally observed rate law. Do you need to assume any species are weakly adsorbed to get agreement with Equation (P10-9.1)?
b. A certain engineer thinks that it would be desirable to operate with a very large stoichiometric excess of CO to minimize catalytic reactor volume. Do you agree or disagree? Explain.
c. What would be the relevance of the problem if everyone were driving a hybrid by 2018? A driverless car by 2020?
Step by Step Answer:
a b Assume that P C P N Then PC changes very little during the course of the reaction and remains co...View the full answer
