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Platinum group metal-free catalysts for reducing the ignition temperature of particulates on a diesel particulate filter

a technology of particulates and catalysts, which is applied in the direction of physical/chemical process catalysts, arsenic compounds, separation processes, etc., can solve the problems of high levels of nosub>x/sub>and particulates in the exhaust gas of diesel engines, the cost of fuel efficiency, and the filter may become plugged, so as to reduce the ignition temperature of particulates

Inactive Publication Date: 2008-09-18
ALIVE KESHAVARAJA +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

"The present invention relates to a catalyst composition for reducing the ignition temperature of particulate matter from diesel exhaust. The catalyst composition includes a first component selected from the group consisting of cerium and a lanthanide, a second component selected from the group consisting of cobalt, copper, manganese, and mixtures thereof, and a third component containing strontium. The first, second, and third components are in an oxide form after calcination. The second component can be cobalt or manganese, and the molar ratio of the first component to the second component to the third component can be in a range of (35-70:5-45:5-35 or (15-60:30-70:5-35, respectively. The catalyst composition can be supported on a substrate, such as a woven fabric, wire mesh, disk filter, ceramic honeycomb monolith, or wall flow filter. The patent also describes a method of removing particulate matter from exhaust gas by contacting it with a catalyzed diesel particulate filter containing the catalyst composition. The technical effect of the invention is to lower the ignition temperature of particulate matter from diesel exhaust, thereby reducing emissions from diesel engines."

Problems solved by technology

Unfortunately, the exhaust gas from diesel engines contains high levels of NOx and particulates.
The filters may become plugged due to the buildup of particulates on the filter.
The exhaust gas temperature can be increased by retarding the timing but at the cost of fuel efficiency.
Heating the electric heater requires energy, with an accompanying fuel efficiency penalty.
The platinum in the CRT™ DOC is expensive.
Further, platinum catalysts may be poisoned by sulfur in the diesel fuel.
Low sulfur diesel fuel is costly.
The fuel-borne additive can be expensive, particularly if the fuel-borne additive is a platinum group metal (PGM).
Further, the fuel-borne additive can form particulate particles that may accumulate on the DPF, making it necessary to change the DPF.
Platinum group metal (PGM) catalysts are expensive.
Vanadium oxides are volatile and toxic.
The high temperatures that are present in the DPF during combustion of the carbon particulates can vaporize the vanadium catalysts on the DPF, potentially leading to health problems in the general populace.

Method used

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  • Platinum group metal-free catalysts for reducing the ignition temperature of particulates on a diesel particulate filter
  • Platinum group metal-free catalysts for reducing the ignition temperature of particulates on a diesel particulate filter
  • Platinum group metal-free catalysts for reducing the ignition temperature of particulates on a diesel particulate filter

Examples

Experimental program
Comparison scheme
Effect test

example 1

Measurement of the CO2 Concentration in the Offgas from the Soot-Loaded Substrate as a Function of Temperature

[0113]Soot-loaded DPF substrates were contacted with a gas stream that comprised about 10% oxygen, about 8% water, about 150 ppm NO, and about 150 ppm NO2. The temperature of the substrate was increased from 200° C. to 650° C. or 700° C., and the concentration of CO2 in the exhaust gas was monitored as a function of temperature.

[0114]FIG. 1 shows a graph of the concentration of CO2 in the exhaust stream versus temperature for a substrate that had been loaded with 2 g / L of soot, with and without a catalyst composition according to an embodiment of the invention. FIG. 1A, the lower curve of FIG. 1, is a graph of the CO2 concentration in the exhaust gas with a blank substrate, a soot-loaded cordierite substrate that does not contain a catalyst composition according to an embodiment of the invention. The catalyst compositions of Examples 1-5 comprise cerium, cobalt, and strontiu...

example 2

Effect of Catalyst Loading on the CO2 Concentration in the Offgas

[0120]FIG. 2 shows a series of curves for the concentration of CO2 versus temperature for substrates with various loadings of a catalyst according to an embodiment of the invention. All of the loadings are on the basis of the oxides.

[0121]Curve 2A is a curve for a substrate with a catalyst loading of 5 g / L, curve 2B for a catalyst loading of 10 g / L, curve 2C for a catalyst loading of 30 g / L, curve 2D for a catalyst loading of 60 g / L, curve 2E for a catalyst loading of 90 g / L, and curve 2F is a curve for a blank, a substrate that does not contain a catalyst.

[0122]As shown in curve 2A, the low temperature CO2 peak for a substrate with a catalyst loading of 5 g / L occurred at about 450° C., compared to about 550° C. in the blank (curve 1A). Increasing the catalyst loading to 10 g / L decreased the temperature of the low temperature peak to about 425° C., as shown in curve 2B. Increasing the catalyst loading from 5 g / L to 10 ...

example 3

Surface Areas and Pore Volumes of Aluminum Oxide Washcoats Prepared from Aluminum Nitrate and Colloidal Alumina

[0127]FIG. 3 shows graphs of the BET surface areas in m2 / g versus target loading in g / L for aluminum oxide washcoats prepared from aluminum nitrate and colloidal alumina.

[0128]Curve 3A of FIG. 3 shows a graph of the BET surface area versus loading for the aluminum oxide washcoats prepared from aluminum nitrate. Curve 3B of FIG. 4 shows a graph of the surface area versus loading for aluminum oxide washcoats prepared with NYACOL® AL20 colloidal alumina.

[0129]As shown in curve 3A, the BET surface area of a substrate that comprised alumina washcoats prepared from aluminum nitrate decreased from about 8 m2 / g to about 3 m2 / g as the target loading was increased from 0 to about 40 g / L. The BET surface areas with alumina washcoats that were prepared with colloidal alumina were higher than the BET surface areas of the corresponding alumina washcoats that were prepared with aluminum o...

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Abstract

A catalyzed diesel particulate filter (CDPF) and a method for filtering particulates from diesel engine exhaust are provided, where the catalyzed diesel particulate filter includes a substrate and a catalyst composition, where the catalyst composition contains at least one first component, at least one second component, and at least one third component, where the first component is at least one first component selected from the group consisting of cerium and a lanthanide and mixtures thereof, the at least one second component is selected from the group consisting of cobalt, copper, manganese and mixtures thereof; and the third component comprises strontium, where the first component, the second component, and the third component are in an oxide form after calcination. The catalyst on the catalyzed diesel particulate filter lowers the temperature at which particulates are removed from the CDPF by oxidizing the particulates on the filter. The catalyzed diesel particulate filter may also include a washcoat. Washcoats prepared from colloidal aluminum oxide may have higher surface areas and pore volumes loadings than washcoats containing aluminum oxide prepared from aluminum nitrate.

Description

RELATED APPLICATIONS[0001]This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application Nos.: 60 / 619,382; 60 / 619,390; and 60 / 619,314, all filed on Oct. 14, 2004, all of which are incorporated herein by reference in their entirety.[0002]This application is a divisional application under 35 USC § 121 of U.S. application Ser. No. 11 / 251,372, which is still pending.”FIELD OF THE INVENTION[0003]Embodiments of the present invention relate to platinum group metal (PGM)-free catalyst compositions for reducing the ignition temperature of particulates on a diesel particulate filter.BACKGROUND[0004]Diesel engines for motor vehicles have good fuel economy and high durability. Unfortunately, the exhaust gas from diesel engines contains high levels of NOx and particulates. Both the United States and Europe have enacted regulations with strict limits on NOx and particulate emissions from diesel engines. The particulate and NOx limits as of 2004 for US trucks are 0.1 ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B01D53/94
CPCB01D53/944B01D2255/204B01D2255/206B01D2255/2073B01D2255/20746B01D2255/20761F01N2510/065B01J23/83B01J37/0205B01J37/0242F01N3/0231F01N3/035F01N2370/02B01J23/34B01J23/02B01D53/94B01D46/04
Inventor ALIVE, KESHAVARAJABAUDOUX, ANN-LAUREGOLDEN, STEPHEN J.
Owner ALIVE KESHAVARAJA
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