Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
In practical applications, monolithic catalytic converters are
operated at non-isothermal conditions. In this case, the active
metal distribution along the length of the converter may
influence its performance. Indeed, better conversions can be
achieved by controlling the distribution of the same quantity of
active material. In this study, we used a one-dimensional
catalyst model to predict the transient thermal and conversion
characteristics of a dual monolithic catalytic converter with
Platinum/Rhodium (Pt/Rh) catalysts. The optimal design of a
longitudinal noble metal distribution of a fixed amount of
catalyst is investigated to obtain the best performance of a dual
monolithic catalytic converter by using a micro genetic
algorithm with consideration of heat transfer, mass transfer, and
chemical reaction in the monolith during FTP-75 cycle. The
optimal design for the optimal axial distribution of the catalyst
is determined by solving the multi-objective optimization
problems which are to minimize both the CO cumulative
emissions during FTP-75 cycle, and the difference between the
integral value of a catalyst distribution function over the
monolith volume and catalytic surface area per unit monolith
volume.
