Copolyamide powder as a pore former in regenerable ceramic particulate filters
AssigneeEvonik Degussa GmbH
InventorsMartin Risthaus, Hans-Joachim Woenicker
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Abstract
A process for producing a regenerable ceramic particulate filter for diesel vehicles is described, wherein a material comprising silicon-containing particles is pyrolyzed in the presence of a polyamide. The resulting particulate filters have a BET surface area of >350 m2/l.
Claims20
A process for producing a regenerable ceramic particulate filter, comprising:
- pyrolyzing a material comprising silicon-containing particles in the presence of a polyamide;
- said regenerable ceramic particulate filter being suitable for a diesel vehicle.
The process according to claim 1, wherein 5 to 15% of a copolyamide powder is added to the material comprising silicon-containing particles and then this polymer, after extrusion, is burnt out again at about 350° C.;
- wherein said silicon-containing particles are silicon carbide particles.
The process according to claim 1, wherein the copolyamide powder has a powder particle size distribution in the range from 0 to 200 μm.
The process according to claim 1, wherein a copolyamide powder based on laurolactam, caprolactam, dodecanedioic acid and methylpentamethylenediamine is used.
The process according to claim 1, wherein the copolyamide powder has a melting point of <150° C.
The process according to claim 1, wherein the pyrolysis takes place at 600 to 1000° C.
A regenerable ceramic particulate filter produced by the process according to claim 1, wherein said regenerable ceramic particulate filter has a BET surface area of >350 m2/l.
A regenerable ceramic particulate filter produced by the process according to claim 1, wherein said regenerable ceramic particulate filter has a BET surface area of 600 to 800 m2/l.
The process according to claim 1, wherein said filter is suitable for filtering particulates from diesel exhaust gas.
The process according to claim 1, wherein the copolyamide powder has a powder particle size distribution in the range from 0 to 80 μm.
The process according to claim 1, wherein, during the pyrolysis, the copolyamide is thermally decomposed virtually completely and leads to the formation of channel walls in said material comprising silicon-containing particles with a wall thickness in the range of 100-480 μm.
The process according to claim 1, wherein said regenerable ceramic particulate filter is a porous SiC-containing ceramic shaped body.
The process according to claim 1, wherein said regenerable ceramic particulate filter is suitable as a catalyst support structure.
The process according to claim 1, wherein said regenerable ceramic particulate filter is suitable as a catalyst system.
The process according to claim 1, wherein the copolyamide powder has a powder particle size in the range from 0 to 200 μm.
The process according to claim 1, wherein the copolyamide powder has a powder particle size in the range from 0 to 80 μm.
Dependencies are inferred from the claim text.