Method for treating an exhaust gas stream
AssigneeTexaco Inc.
InventorsKashmir S. Virk, Martin Alperstein
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Abstract
Method for filtering combustible particles from an exhaust gas stream, and for periodically rejuvenating the filter bed and catalyst section thereof, by incinerating retained particles. At least a portion of an engine's exhaust gas stream is initially preheated in the catalyst section to raise said section to a predetermined "lightoff" temperature. A supplementary fuel is then introduced to the heated exhaust gas stream prior to the latter entering the catalyst section, thereby causing the fuel/gas mixture to react. Subsequent to initiation of this oxidation reaction, further preheating energy input to increase the exhaust gas to "lightoff" temperature, can be discontinued without affecting the combustible particle incineration rate.
Claims3
Method for treating a diesel engine exhaust gas stream to remove combustible particles which are carried in the stream, which method includes the steps of;
- passing the particle-carrying exhaust gas stream through a filter bed which includes an oxidizing catalytic segment therein, whereby to retain said combustible particles in said filter bed,
- at spaced intervals of time during operation of said engine, periodically incinerating said retained particles to purge the filter bed thereof by:
- separating the exhaust gas stream into minor and major portions,
- heating the minor portion to a temperature at least in excess of the oxidizing catalyst lightoff temperature,
- introducing a fuel component into the heated exhaust gas portion to establish a fuel/gas mixture,
- passing said heated fuel/gas mixture through said catalytic segment to combust the said mixture.
Dependencies are inferred from the claim text.