J. Paul Day

The Design of a New Ceramic Catalyst Support

The development of a stronger cordierite material with much less porosity than the current material allows the manufacture of catalytic substrates with the same strength as the current part but with proportionately thinner walls. In the process of analyzing the properties of this new substrate it was discovered that optimum performance can be realized by using specially chosen combinations of cell density and wall thickness. Using the properties of this new material and the equations which relate material and structural features to substrate performance, substrate designs have been identified which in one case minimize the back pressure while maintaining the catalyst performance at the present level, and in another case maximise the catalyst performance while maintaining the back pressure at the present level. Other optimum design points are also indicated. For the covering abstract see IRRD 851463.

A Rotary Heat Exchanger for Automotive and Other Ground Based Gas Turbines

This paper discusses the ongoing development of a ceramic regenerator for a high temperature automotive gas turbine engine sponsored by the U.S. Department of Energy.The ceramic gas turbine has a steady state gas inlet temperature of 774°C and a 982°C peak acceleration temperature which precludes the use of metallic discs. Ceramic materials have successfully operated to 982°C, with a peak acceleration temperature exceeding 1093°C. Ceramic regenerator temperature capability is currently limited by seal tribomaterial properties.The requirements of the ceramic regenerator, ceramic disc materials being evaluated, and the processing of these materials to obtain the required strength, chemical resistance, cost, including quality control are discussed. The status of the extruded regenerator program to date will also be described.Copyright

Impact of Catalyst Support Design Parameters on Automotive Emissions

Ceramic monolithic catalyst supports have been an integral part of automotive emissions control systems since the early 70s. This investigation examines the impact of physical (cell density, frontal area, volume) and material (porosity, thermal mass) design parameters on vehicle emissions and pressure drop. This study indicates that CO and HC emissions can be reduced by larger volume and/or higher cell density substrates. Materials changes have little or no impact on catalyst performance. Pressure drop is increased by using a longer substrate, and dramatically reduced with a larger frontal area part.

Substrate contributions to automotive catalytic converter performance : The role of channel shape on catalyst efficiency

ABSTRACT The catalyst support plays an integral part in the performance of the automotive catalytic converter system. Although the precious metal catalyst is the primary contributor to the conversion efficiency, the substrate role is to properly distribute and support the washcoat and precious metal catalyst in order to utilize the properties of these components most fully. By optimizing the substrate properties as well as the precious metal and washcoat systems, optimum benefit from the catalyst system can be obtained. The automotive catalyst support is composed of the material and the structure. Previous papers have dealt with the materials. This paper will describe the structure of the catalyst support, specifically the channel shape, and present the structure-related heat transfer, mass transfer, and pressure drop properties for the laminar flow condition for various channel shapes. After these relationships have been established, a comparison will be made between the catalyst system performance of two of the channel shapes available commercially.