Methods of making porous crystalline materials and their use in hydrocarbon sorption
AssigneeExxonMobil Research and Engineering Company
InventorsBrian M. Weiss, Scott J. Weigel, Karl G. Strohmaier, William W. Lonergan
Life of this patent
Estimating the term…
Abstract
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.
Claims32
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 %.
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 an 11-membered ring pore channel 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 %.
A hydrocarbon sorption apparatus comprising a porous crystalline material bed, the porous crystalline material bed comprising a porous crystalline material (1) containing both 10- and 12-membered ring pore channels or (2) containing an 11-membered ring pore channel, 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 %.
Dependencies are inferred from the claim text.