Abstract: Carbon black pellets which can be produced by the addition of wax during dry granulation of carbon black powder. The carbon black pellets are distinguished by a pellet hardness of at least 0.15 N with a wax content of less than 10 wt. %, based on the total weight of the carbon black pellets.
Type:
Grant
Filed:
December 16, 1998
Date of Patent:
October 17, 2000
Assignee:
Degussa Aktiengesellscaft
Inventors:
Conny Vogler, Karl Vogel, Udo Wieschnowsky, Jan Kopietz
Abstract: An exhaust gas purification catalyst with improved hydrocarbon conversion is disclosed, which contains metals from the platinum group as its catalytically active components. Two superposed functional layers are applied to one support. The catalyst has a first functional layer with a mixture of a first catalyst with at least one zeolite and the second functional layer applied to the first functional layer which contains a mixture of a second catalyst and at least one zeolite. The zeolites exhibit a molar ratio of silicon dioxide/aluminum oxide of more than 40 and in that at least palladium and rhodium are present as the platinum group metals and are each contained separately from one another in only one of the two catalysts. The catalyst is distinguished by particularly good suppression of hydrocarbon emissions during cold-starting and exhibits particularly good long-term stability.
Type:
Grant
Filed:
November 12, 1997
Date of Patent:
June 27, 2000
Assignee:
Degussa Aktiengesellscaft
Inventors:
Lothar Mussmann, Dieter Lindner, Renee Van Yperen, Egbert Lox, Thomas Kreuzer