California Institute of Technology

Chevron U.s.a. Inc.

Tatsuya Okubo

Stacey Ian Zones

Mark E Davis

Cong-Yan Chen

Allen W Burton, Jr

Shanmugam Palani Elangovan

A method of treating a cold-start engine exhaust gas stream comprising hydrocarbons and other pollutants, the method comprising: flowing the exhaust gas stream over a molecular sieve bed, the molecular sieve bed comprising an alkali metal cation-exchanged molecular sieve having intersecting 10- and 12-membered ring pore channels, to provide a first exhaust stream; flowing the first exhaust gas stream over a catalyst to convert any residual hydrocarbons and other pollutants contained in the first exhaust gas stream to innocuous products to provide a treated exhaust stream; and discharging the treated exhaust stream into the atmosphere.

Treatment of cold start engine exhaust

Molecular sieves and the use of such materials as hydrocarbon traps, particularly for reducing the emissions associated with the combustion of hydrocarbon fuels are described. Specifically, the use of molecular sieves such as zeolites as adsorbents for hydrocarbon gases, especially exhaust gases such as are formed during the combustion of hydrocarbons, and more particularly to the adsorption of hydrocarbon gases formed during the cold start operation of an internal combustion engine is described. In one embodiment, a method of treating exhaust gas that comprises a hydrocarbon combustion product is provided, the method comprising contacting the exhaust gas with a CON topology molecular sieve for a time period effective to facilitate adsorption of the hydrocarbon combustion product by the molecular sieve; passing a purge gas through the molecular sieve to remove adsorbed hydrocarbon combustion product; and contacting the purge gas containing the removed hydrocarbon combustion product with a hydrocarbon conversion catalyst.

Molecular sieves for improved hydrocarbon traps

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Machida, Japan

Tatsuya Okubo