METHODS OF MAKING POROUS CRYSTALLINE MATERIALS AND THEIR USE IN HYDROCARBON SORPTION

摘要

The present invention relates to a hydrothermally stable form of a porous crystalline material useful in applications where sorbing hydrocarbons is desired. Among such applications is sorption of hydrocarbons from an exhaust stream from an engine in a cold-start condition. A hydrocarbon sorption apparatus including the hydrothermally stable porous crystalline material is provided. In either case, the hydrothermally stable porous crystalline material can contain both 10- and 12-membered ring pore channels, or alternately an 11-membered ring pore channel, as well as have one or more other properties.

主权项

1. A method of treating a cold-start engine exhaust gas stream comprising hydrocarbons and/or other pollutants, the method comprising:
a) flowing the exhaust gas stream over a bed of a porous crystalline material, the porous crystalline material containing both 10- and 12-membered ring pore channels to provide a first treated exhaust stream having lower total hydrocarbon content than that of the exhaust gas stream, wherein the porous crystalline material exhibits one or more of the following properties:
(i) a decrease in micropore volume no more than about 15% after exposure to 100% steam at 800° C. and atmospheric pressure for 5 hours;(ii) a surface hydroxyl group content after exposure to 100% steam at 800° C. and atmospheric pressure for 5 hours that is less than one or more of (a) a surface hydroxyl group content of an otherwise identical but unsteamed porous crystalline material, (b) a surface hydroxyl group content of an otherwise identical porous crystalline material after exposure to 100% steam at a temperature of 550° C. and atmospheric pressure for 5 hours, and (c) a surface hydroxyl group content of an unsteamed porous crystalline material having a monovalent metal cation content of at least 1.3 wt %;(iii) a monovalent metal cation content of 1.0 wt % or less of the porous crystalline material;(iv) a content of ammonium ions (NH4+) of at least 0.5 wt %; and(v) a content of multivalent metal ions of at least 0.5 wt %.