John K. Hochmuth

Catalytic partial oxidation of methane over a monolith supported catalyst

Abstract The catalytic partial oxidation of methane over a monolithic supported catalyst to produce synthesis gas was investigated in pilot plant experiments conducted at commercially feasible operating conditions. It was demonstrated that, with air as the oxidant, an equilibrium synthesis gas could be produced at very high space velocity. Measured axial composition and temperature profiles provided some evidence that the oxidation step was a near total oxidation step producing carbon monoxide, carbon dioxide, and water. No carbon was found on the catalyst under the conditions investigated, and the process condensate was clean.

Cold start hydrocarbon emissions control via admixing three way conversion catalysts with heat exchange and hydrocarbon adsorption phenomena

Abstract The revisions in the United States Clean Air Act of 1990 and recent regulatory actions taken by the California Air Resources Board and European Economic Community require the development of automobiles with much lower tail pipe emissions. A significant portion of the total pollutants emitted to the atmosphere by motor vehicles occurs immediately following the startup of the engine when the engine block and exhaust manifold are cold, and the catalytic converter has not yet reached high conversion efficiencies. To meet these stringent, mandated emission levels, new technologies must be created that attack these “cold start” pollutants. One intriguing strategy for handling cold start emissions employs hydrocarbon adsorbers. The sorber scavenges and withholds hydrocarbons from the exhaust gas until the catalyst becomes active, then the hydrocarbons are released and burned on the catalyst. Recent advances in materials technology have uncovered non-carbon-based sorbent alternatives to the classic carbon-based beds. These solids also trap via a physical interaction between the hydrocarbons and the scavenging constituent, but display better thermal stability, especially in the presence of oxygen. To take advantage of these new hydrocarbon scavenging constituents, an auto exhaust system known as the Low Hydrocarbon Emissions System (LHES) composed of a catalyzed heat exchanger and hydrocarbon trap has been designed and tested. The system was custom fitted onto several 1993 vehicles with a variety of engine management strategies. In each case U.S. FTP 75 total hydrocarbon emissions were reduced between 45–75% versus the vehicles stock exhaust system. The LHES system also proved resistant to an accelerated thermal aging that was equivalent to 50,000 miles. A deactivation factor for all pollutants of 1.0 was calculated for the LHES following a 75 hr engine test bed aging with the heat exchanger inlet gas temperature set at 760°C.

Progress in the development of NOx adsorber catalysts for DI gasoline engines

In this article by Engelhard Technologies, recent progress in NOx trap emission control for lean-burn gasoline engines is described on the basis of defined performance criteria. The influence of different ageing conditions on the maximum temperature stability of NOx adsorbers is presented. The maximum temperature stability and the operating temperature range of current NOx adsorbers require the use of a close-coupled pre-catalyst. For series application, the maximum temperature load of the adsorbers must be limited in order to guarantee durability.

Entwicklungsfortschritte bei NOx-Adsorberkatalysatoren für DI-Ottomotoren

Entwicklungsfortschritte bei der Abgasnachbehandlung fur Ottomotoren im Magerbetrieb mittels NOx-Speicherkatalysatoren werden im vorliegenden Beitrag von Engelhard Technologies anhand von Beurteilungskriterien beschrieben. Hinsichtlich der maximalen Temperaturstabilitat wird der Einfluss unterschiedlicher Alterungen auf den NOx-Adsorber dargestellt. Die zur Zeit vorhandene Temperaturstabilitat und der Arbeitstemperaturbereich aktueller Adsorber bedingen den Einsatz eines krummernahen Vorkatalysators. Fur aktuelle Serienanwendungen ist die maximale Temperaturbelastung der Adsorber zu begrenzen, um die Dauerhaltbarkeit zu gewahrleisten.