Light‐off location and front diffusion in a catalytic monolith reactor

Abstract

in Wiley InterScience (www.interscience.wiley.com).A one-dimensional solid-gas model has been used to study the light-off behavior in a reactor system. Techniques from nonlinear analysis are applied to first arrive at an analytical expression to estimate the light-off location in the reactor. The model is then extended to estimate the thickening of the light-off front in the vicinity of the light-off location due to heat diffusion effects in the solid substrate. Both these results are expressed in terms of all the important operating and design variables of the monolith reactor and also the reaction specific variables such as the kinetic parameters and heats of reaction. A specific case of a three-way catalyst (TWC) is numerically treated in detail to illustrate the application of this work. Finally, we focus on using the insight obtained from this study to suggest design guidelines to optimize the performance of automotive catalytic monolith reactors.

Hydrogenation of dimethyl oxalate to ethylene glycol on a Cu/SiO2/cordierite monolithic catalyst: Enhanced internal mass transfer and stability

“…Compared with the traditional packed‐bed reactor, the monolithic catalyst has several inherent advantages such as high‐transport rates of heat and mass per unit pressure drop, high surface area to volume ratios, small transverse temperature gradients and ease of scale‐up 27–29. It has been widely used in treating the exhaust from gasoline powered vehicles, catalytic oxidation of VOCs, removal of NO x from lean burn and diesel engines, power plant, and furnace exhaust gases for the last two decades 30–33.…”

Electrically Heated Catalysts for Hybrid Applications: Mathematical Modeling and Analysis

“…Light-off temperatures for given exhaust gas compositions and catalyst loading can be obtained from engine/lab experiments or with the help of nonlinear tools and analytical expressions provided in Ramanathan and Gopinath. 29 Additionally, the critical temperature could be different for preand postheating for the heating strategy to be effective. [Note that a temperature based control strategy as mentioned above can be used for conventional applications as well].…”

“…Since this will be the temperature of the heater (and not the exhaust gas), it may be more efficient to have the critical temperature 10−20 °C higher than the light-off temperature so that there is a significant driving force for the heat transfer from the heater to the exhaust gas (when the exhaust gas temperatures are below the light-off temperatures). Light-off temperatures for given exhaust gas compositions and catalyst loading can be obtained from engine/lab experiments or with the help of nonlinear tools and analytical expressions provided in Ramanathan and Gopinath . Additionally, the critical temperature could be different for pre- and postheating for the heating strategy to be effective.…”