University of California

George E Vogtlin

Bernard T Merritt

Bernardino M Penetrante

Raymond M Brusasco

P Henrik Wallman

Mark C Hsiao

Troy W Barbee, Jr

John G Reynolds

Gary W Johnson

Ronald S Lee

Dennis W O'Brien

David A Goerz

Robert L Druce

Ray Brusasco

Bernie M Penetrante

Mark Hsiao

A high-surface-area (greater than 600 m2/g), large-pore (pore size diameter greater than 6.5 angstroms), basic zeolite having a structure such as an alkali metal cation-exchanged Y-zeolite is employed to convert NO contained in an oxygen-rich engine exhaust to N and O . Preferably, the invention relates to a two-stage method and apparatus for NO reduction in an oxygen-rich engine exhaust such as diesel engine exhaust that includes a plasma oxidative stage and a selective reduction stage. The first stage employs a non-thermal plasma treatment of NO gases in an oxygen-rich exhaust and is intended to convert NO to NO in the presence of O and added hydrocarbons. The second stage employs a lean-NO catalyst including the basic zeolite at relatively low temperatures to convert such NO to environmentally benign gases that include N , CO , and H O.

Highly-basic large-pore zeolite catalysts for NOx reduction at low temperatures

A two-stage method for NO reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO gases in an oxygen-rich exhaust and is intended to convert NO to NO in the presence of O and hydrocarbons. The second stage employs a lean NO trap to convert such NO to environmentally benign gases that include N , CO , and H O. By preconverting NO to NO in the first stage with a plasma, the efficiency of the second stage for NO reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO in the presence of O and hydrocarbons, such as propene. A flow of such hydrocarbons (C H ) is input from usually a second pipe into at least a portion of the first chamber. The NO from the plasma treatment proceeds to a storage reduction catalyst (lean NO trap) that converts NO to N , CO , and H O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO are simultaneously reduced while passing through the lean-NO trap catalyst. The method allows for enhanced NO reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Plasma-assisted catalytic storage reduction system

Hydrocarbon co-reductants, such as diesel fuel, are added by pulsed injection to internal combustion engine exhaust to reduce exhaust NO,to N,in the presence of a catalyst. Exhaust NO,reduction of at least 50% in the emissions is achieved with the addition of less than 5% fuel as a source of the hydrocarbon co-reductants. By means of pulsing the hydrocarbon flow, the amount of pulsed hydrocarbon vapor (itself a pollutant) can be minimized relative to the amount of NO,species removed.

Nox reduction system utilizing pulsed hydrocarbon injection

Hydrocarbons, such as diesel fuel, are added to internal combustion engine exhaust to reduce exhaust NO.sub.x in the presence of a amphoteric catalyst support material. Exhaust NO.sub.x reduction of at least 50% in the emissions is achieved with the addition of less than 5% fuel as a source of the hydrocarbons.

Nitrogen oxide removal using diesel fuel and a catalyst

A non-catalytic two-stage process for removal of NO.sub.x and particulates from engine exhaust comprises a first stage that plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, and a second stage, which preferably occurs simultaneously with the first stage, that converts NO.sub.2 and carbon soot particles to respective environmentally benign gases that include N.sub.2 and CO.sub.2. By preconverting NO to NO.sub.2 in the first stage, the efficiency of the second stage for NO.sub.x reduction is enhanced while carbon soot from trapped particulates is simultaneously converted to CO.sub.2 when reacting with the NO.sub.2 (that converts to N.sub.2). For example, an internal combustion engine exhaust is connected by a pipe to a chamber where carbon-containing particulates are electrostatically trapped or filtered and a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. Volatile hydrocarbons (C.sub.x H.sub.y) from the trapped particulates are oxidized in the plasma and the remaining soot from the particulates reacts with the NO.sub.2 to convert NO.sub.2 to N.sub.2, and the soot to CO.sub.2. The nitrogen exhaust components remain in the gas phase throughout the process, with no accompanying adsorption.

Plasma regenerated particulate trap and NO.sub.x reduction system

A two-stage method for NO.sub.x reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO.sub.x gases in an oxygen-rich exhaust and is intended to convert NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. The second stage employs a lean NO.sub.x trap to convert such NO.sub.2 to environmentally benign gases that include N.sub.2, CO.sub.2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage with a plasma, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, such as propene. A flow of such hydrocarbons (C.sub.x H.sub.y) is input from usually a second pipe into at least a portion of the first chamber. The NO.sub.2 from the plasma treatment proceeds to a storage reduction catalyst (lean NO.sub.x trap) that converts NO.sub.2 to N.sub.2, CO.sub.2, and H.sub.2 O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the lean-NO.sub.x trap catalyst. The method allows for enhanced NO.sub.x reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Non-thermal plasma gas treatment is combined with selective catalytic reduction to enhance NO.sub.x reduction in oxygen-rich vehicle engine exhausts.

Catalytic reduction system for oxygen-rich exhaust

A two-stage catalyst comprises an oxidative first stage and a reductive second stage. The first stage is intended to convert NO to NO.sub.2 in the presence of O.sub.2. The second stage serves to convert NO.sub.2 to environmentally benign gases that include N2, CO2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber. An oxidizing first catalyst converts NO to NO.sub.2 in the presence of O.sub.2 and includes platinum/alumina, e.g., Pt/Al.sub.2 O.sub.3 catalyst. A flow of hydrocarbons (C.sub.x H.sub.y) is input from a pipe into a second chamber. For example, propene can be used as a source of hydrocarbons. The NO.sub.2 from the first catalyst mixes with the hydrocarbons in the second chamber. The mixture proceeds to a second reduction catalyst that converts NO.sub.2 to N2, CO2, and H.sub.2 O, and includes a gamma-alumina .gamma.-Al.sub.2 O.sub.3. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the second catalyst.

Pre-converted nitric oxide gas in catalytic reduction system

A slapper detonator comprises a solid-state high-voltage capacitor, a low-jitter dielectric breakdown switch and trigger circuitry, a detonator transmission line, an exploding foil bridge, and a flier material. All these components are fabricated in a single solid-state device using thin film deposition techniques.

Method and system for making integrated solid-state fire-sets and

Reduction of NO.sub.x from diesel engine exhaust by use of plasma-regenerated absorbent beds. This involves a process for the reduction of NO.sub.x and particulates from diesel engines by first absorbing NO.sub.x onto a solid absorbent bed that simultaneously acts as a physical trap for the particulate matter, and second regenerating said solid absorbent by pulsed plasma decomposition of absorbed NO.sub.x followed by air oxidation of trapped particulate matter. The absorbent bed may utilize all metal oxides, but the capacity and the kinetics of absorption and desorption vary between different materials, and thus the composition of the absorbent bed is preferably a material which enables the combination of NO.sub.x absorption capability with catalytic activity for oxidation of hydrocarbons. Thus, naturally occurring or synthetically prepared materials may be utilized, particularly those having NO.sub.x absorption properties up to temperatures around 400.degree. C. which is in the area of diesel engine exhaust temperatures.

Growing community of inventors

Fremont, CA, United States of America

George E Vogtlin