Patent DE-102006035718-A1 (DE)
Title: Preparing dehydrogenated hydrocarbon comprises providing a gaseous reaction mixture stream containing hydrocarbon at an increased temperature through a catalyst bed system, and supplying a volume flow of e.g. molecular oxygen
Inventor: DIETERLE MARTIN
IPC: C08F20/10
Filed: 2006-07-28
Abstract: Preparation of dehydrogenated hydrocarbon, comprises providing a gaseous reaction mixture stream containing the hydrocarbon at an increased temperature through a catalyst bed system present in a reaction zone; and optionally supplying a volume flow of molecular oxygen, molecular hydrogen, water vapor and/or another inert gas that act as auxiliary gases for the dehydrogenation reaction, to the gaseous reaction mixture stream between its entry at the start of the catalyst bed system and its exit from the end of the catalyst bed system. Procedure for the long-term operation of a continuously-operated and heterogeneously-catalyzed partial dehydrogenation process of a hydrocarbon to be dehydrogenated to form a dehydrogenated hydrocarbon, comprises providing a gaseous reaction mixture stream containing the hydrocarbon in an initial molar volume (KW), at an increased temperature through a catalyst bed system, which is present in a reaction zone (RZ) and consist of many catalyst bed sections that are arranged serially along the flow direction of the gaseous reaction mixture stream, and as a whole consists a molar volume (M) of a dehydrogenation catalyst; where: at the time of operation t is t 0, the passage of the gaseous reaction mixture stream through first, second and last third portion of (M) along the flow direction output, proportions of A, B and C mol.% of (KW) of the hydrocarbon to be dehydrogenated are respectively converted to form dehydrogenated hydrocarbon, under the condition that A is greater than B and B is greater than C and during the passage of the gaseous reaction mixture stream through the catalyst bed system, a total (G) i.e. A+B+C mol.% of (KW) of the hydrocarbon to be dehydrogenated that is contained in this reaction mixture stream is dehydrogenated to form dehydrogenated hydrocarbon, and optionally supplying a volume flow of molecular oxygen, molecular hydrogen, water vapor and/or another inert gas that act as auxiliary gases for the dehydrogenation reaction, to the gaseous reaction mixture stream between its entry at the start of the catalyst bed system and its exit from the end of the catalyst bed system, where deactivation of the catalyst bed system that advances with increasing operating time within an operation time interval of greater than t 0 and less than t r is counteracted by varying the temperature profile of the gaseous reaction mixture stream within the catalyst bed system and/or the volume flow of the optionally supplied auxiliary gases for the dehydrogenation reaction, where t r is the operating time point at which the dehydrogenation is interrupted and the catalyst bed system is at first recovered after the operating time point of t 0, thus the variation is carried out in such a manner that with increasing operating time point, the proportion A decreases, the proportion B undergoes a maximum and the proportion C increases.