TY  - GEN
N2  - Within this work various catalysts for the direct synthesis of dimethyl ether from CO-rich
synthesis gas have been investigated and tested in a continuously operating laboratory
plant. The employed catalyst systems have been either bifunctional catalysts, which
combine active sites for the methanol synthesis and its dehydration, or admixed
catalysts consisting of a conventional methanol catalyst and different acid solids.
The catalysts have been prepared by wet-chemical methods, the sol-gel-process,
hydrothermal reaction, deposition of complexes and colloids on an acid solid and by
flame-spray pyrolysis. The latter method proved to be very efficient for the preparation of
highly active methanol- and dimethyl ether-catalysts. The flame-made methanol catalyst
showed high synthesis gas conversion and in combination with ?-Al2O3 a very good
dimethyl ether selectivity that were as high as in the case of a commercially available
methanol catalyst.
Various admixed catalyst systems have been tested focusing on their long-term stability.
A system that contained the zeolite H-MFI 400 as dehydration component showed the
highest CO-conversion. However, this system was not stable and its activity decreased
after a catalyst passivation and -regeneration process. A catalyst system containing a
SiO2-doped alumina was the most stable in the passivation and regeneration process,
because the high metal dispersion in the catalyst did not change during the procedure.
The obtained data show that the synergy between the active sites for methanol
synthesis and the active sites for methanol dehydration plays an important role for
catalyst activity. Therefore, an overlapping of the active sites needs to be prevented for
the preparation of highly active bifunctional catalysts.
A1  - Ahmad, Ruaa
TI  - Katalysatorsynthese umd -optimierung für die DME-Direktsynthese aus CO-reichem Synthesegas
AV  - public
ID  - heidok16438
Y1  - 2014///
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/16438/
ER  -