Kenneth Baron

Bio: Kenneth Baron is an academic researcher from General Motors. The author has contributed to research in topics: Catalysis & Carbon monoxide. The author has an hindex of 11, co-authored 18 publications receiving 607 citations.

Poison-resistant catalysts for the simultaneous control of hydrocarbon, carbon monoxide and nitrogen oxide emissions

Abstract: Experiments designed to answer certain questions about the mechanism of operation and of deactivation of catalysts near stoichiometric conditions were carried out. This involved special catalysts preparations tested in laboratory equipment and in vehicles. We concluded that the poisoning process at exhaust stoichiometry appears to be very similar to the poisoning process under net oxidizing conditions; that is, only a sharply defined outer shell of the pellets is poisoned, this shell progressing inward as time elapses. Based on these experiments, the following catalyst design concept was developed: To utilize the different properties of Pt, Pd and Rh, all three will have to be employed in a special design corresponding to their ratio in ores. To avoid interferences, they should not be coimpregnated over the same support surface; one way to avoid coimpregnation is to impregnate them in separate layers in the catalyst pellets. Due to its relative poison insensitivity Pt should be the outer layer, while Pd and Rh should be protected from the poison front. Consequenty, the Pt impregnation depth (from the outer surface) is given by the depth to which the poisons penetrate. Due to the importance of Rh in catalyzing the NO reduction reaction at the (diffusionmore » controlled) rich end of the A/F scale, Rh should be impregnated as close to the surface of the pellet as possible, while still being protected from poisoning. Consequently, Rh should be impregnated right below the Pt layer and Pd underneath the Rh layer. Due to the transient nature of the feedstream's A/F, it appears to be beneficial to include an agent in catalyst formulations which, by storing and slowly releasing some of the components from the surface, tends to smooth out the effects of A/F oscillations. The results are encouraging; real-time engine dynamometer and vehicle aging tests are required, however, to prove their durability in actual automobile service.« less

Multiple steady states in an isothermal, integral reactor: the catalytic oxidation of carbon monoxide over platinum--alumina

Abstract: Stable isothermal multiplicities were observed during carbon monoxide oxidation in an integral reactor, filled with alumina supported platinum catalysts. The multiplicities were investigated in the conversion-temperature, conversion-inlet carbon monoxide concentration and conversion-mass flow rate domains. The region of multiplicities was found to widen significantly upon catalyst aging which enhanced the pellets' diffusive resistances. Several intermediate stable steady states were found between the highest and lowest steady states, both experimentally and theoretically. All the above phenomena could be well interpreted by the interactions of the kinetics of carbon monoxide oxidation with intrapellet diffusion resistances.

Biomechanical Analysis of Indy Race Car Crashes

Abstract: This paper describes the results of an ongoing project in the GM Motorsports Safety Technology Research Program (MSTRP) to investigate lndianapolis-type (Indy car) race car crashes using an on-board impact recorder as the primary data collection tool. The paper discusses the development of specifications for the impact-recording device, the selection of the specific recorder, and its implementation on a routine basis in Indy car racing. The results from incidents that produced significant data during the racing seasons from 1993 through the first half of 1998 are summarized. Examples of impact recordings are given which are remarkable in terms of the severity of crashes and, in most cases, the resulting lack of significant injuries. A total of 202 cases with peak decelerations above 20 G are summarized. The mean peak rigid body chassis decelerations for the sample were on the order of 53 G. Peak decelerations in excess of 60 G (some as high as 127 G) have been recorded for significant durations in many frontal, side, and rear impacts. Associated mean total velocity change was 28.3 mph for the sample. The relatively tight coupling of the driver's torso to the chassis allows direct inferences of the loads on the torso, particularly in side impacts. The data calls into question the use of chest acceleration as an injury assessment criterion in both frontal and side impacts. For the covering abstract of the conference see IRRD E201429.

Catalytic Properties of Ceria and CeO2-Containing Materials

Abstract: Over the past several years, cerium oxide and CeO2-containing materials have come under intense scrutiny as catalysts and as structural and electronic promoters of heterogeneous catalytic reactions. Recent developments regarding the characterization of ceria and CeO2-containing catalysts are critically reviewed with a special focus towards catalyst interaction with small molecules such as hydrogen, carbon monoxide, oxygen, and nitric oxide. Relevant catalytic and technological applications such as the use of ceria in automotive exhaust emission control and in the formulation of SO x reduction catalysts is described. A survey of the use of CeO2-containing materials as oxidation and reduction catalysts is also presented.

Mechanisms of catalyst deactivation

Abstract: The literature treating mechanisms of catalyst deactivation is reviewed. Intrinsic mechanisms of catalyst deactivation are many; nevertheless, they can be classified into six distinct types: (i) poisoning, (ii) fouling, (iii) thermal degradation, (iv) vapor compound formation accompanied by transport, (v) vapor-solid and/or solid-solid reactions, and (vi) attrition/crushing. As (i), (iv), and (v) are chemical in nature and (ii) and (v) are mechanical, the causes of deactivation are basically three-fold: chemical, mechanical and thermal. Each of these six mechanisms is defined and its features are illustrated by data and examples from the literature. The status of knowledge and needs for further work are also summarized for each type of deactivation mechanism. The development during the past two decades of more sophisticated surface spectroscopies and powerful computer technologies provides opportunities for obtaining substantially better understanding of deactivation mechanisms and building this understanding into comprehensive mathematical models that will enable more effective design and optimization of processes involving deactivating catalysts. © 2001 Elsevier Science B.V. All rights reserved.

Heterogeneous Catalyst Deactivation and Regeneration: A Review

Abstract: Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical) and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing). The key features and considerations for each of these deactivation types is reviewed in detail with reference to the latest literature reports in these areas. Two case studies on the deactivation mechanisms of catalysts used for cobalt Fischer-Tropsch and selective catalytic reduction are considered to provide additional depth in the topics of sintering, coking, poisoning, and fouling. Regeneration considerations and options are also briefly discussed for each deactivation mechanism.

Nitric oxide catalysis in automotive exhaust systems

Abstract: This review covers the literature through 1991 on nitric oxide catalysis as applied to automobile exhaust systems. Attention is given to the threeway catalyst system which simultaneously promotes the reduction of nitrogen oxides and the oxidation of carbon monoxide and hydrocarbons. These systems have been used on most passenger cars in the United States since 1982. Prior to 1980, emission control catalysts were oxidation catalysts, and reduction in exhaust nitric oxide was achieved using engine modifications (i.e., exhaust gas recirculation). This review focuses on catalytic control of NO, for gasoline-fueled vehicles (not diesels and alternate fuels) and primarily on developments reported since 1982. The term NO, refers to both NO and NOz. The reader is referred to an earlier publication by the author for a general review of automobile catalytic converters [1] and to a review by Egelhoff [2] on the nitric oxide literature through 1980. The recent literature on NO, reduction in lean exhaust is c...

Monoliths in Heterogeneous Catalysis

Abstract: The use of structured catalysts in the chemical industry has been considered for years. Conventional fixed-bed reactors have some obvious disadvantages such as maldistributions of various kinds (including a nonuniform access of reactants to the catalytic surface), high pressure drop in the bed, etc. Structured catalysts are promising as far as elimination of these setbacks is concerned. Two basic kinds of structured catalysts can be distinguished: Structural packings covered with catalytically active material, similar in design to those used in distillation and absorption columns and/or static mixers. Good examples of catalysts of this kind are those offered by Sulzer, clearly developed by Sulzer column packings and static mixers. As in packed beds, there is an intensive radial convective mass transport over the entire cross-section of these packings. Structural packing catalysts and the reactors containing them are, however, not within the scope of this review. Monolithic catalysts are continuou...