Ceramic Foam Catalyst Substrates for Diesel Oxidation Catalysts: Pollutant Conversion and Operational Issues

Abstract

In the field of automotive exhaust catalysts, foam-type substrates have been proposed as alternatives to the wellestablished honeycomb substrates. The ceramic foams developed and manufactured in our laboratory are capable of redistributing the flow of exhaust gases, enhancing turbulence, mass transfer and species mixing, without increasing flow resistance and pressure drop to prohibitive levels. Based on the characteristics of turbulent mass and heat transfer, ceramic foam based catalysts have the potential for achieving similar pollutant conversion performances as state of art honeycomb catalysts with substantially lower precious metal requirements. The conversion performances achieved with the foam catalyst were almost equal to those achieved by the honeycomb in respect to CO and THC oxidation, although honeycombs had 2.8 times more precious metals. In addition, the foams exhibited substantially better particle oxidizing behavior, as particle number measurements have shown. Nevertheless, NO oxidation light-off performance of the foams was worse. This may be attributed to different wash coat compositions, the wash coat composition of the serial production honeycomb was not fully known. The comparison of two differently coated foam DOCs have given insights in the conversion dependencies on the coating parameters and have shown further optimization directions.

Heat-Up Performance of Catalyst Carriers—A Parameter Study and Thermodynamic Analysis

“…In contrast to the cellular monolithic substrates mentioned, non-cellular substratesrigid foams made of cordierite, silicon carbide, or metal-were also developed, see, e.g., [24,25]. The results published by Jatkar indicate that metallic foams provide a proper support structure for automotive catalysts.…”

Effects of the internal structures of monolith ceramic substrates on thermal and hydraulic properties: additive manufacturing, numerical modelling and experimental testing

“…Honeycomb monoliths are available in different cell density and shapes. Nevertheless, the most common commercial honeycomb is a square channelled 400 CPSI [14,26,45,46]. Therefore, a square channelled honeycomb monolith with 400 CPSI and 0.2 mm thick walls is used as the benchmark.…”

Analysis of the Effects of Catalytic Converter on Automotive Engines Performance Through Real-Time Simulation Models

“…Following this consideration, and in order to investigate the effects of different catalyst substrates on powertrains performance, a model of the after-treatment system has been developed and coupled with a "crank-angle" engine model (Gambarotta and Lucchetti, 2013). Particular attention has been given to foams as an innovative material for substrates (Bach and Dimopoulos Eggenschwiler, 2011). Obtained results are shown in the paper.…”