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Title: Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates Using Supported Rh Catalysts in a Microchannel Reactor

Abstract

Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates Using Supported Rh Catalysts in a Microchannel Reactor

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
984247
Report Number(s):
PNNL-SA-46305
Journal ID: ISSN 0920-5861; CATTEA; 9303; BM0101010; TRN: US201015%%903
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Catalysis Today, 120(1):90-95; Journal Volume: 120; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; ALCOHOLS; CATALYSTS; METHANE; SUBSTRATES; SYNTHESIS; Environmental Molecular Sciences Laboratory

Citation Formats

Hu, Jianli, Wang, Yong, Cao, Chunshe, Elliott, Douglas C., Stevens, Don J., and White, James F. Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates Using Supported Rh Catalysts in a Microchannel Reactor. United States: N. p., 2007. Web. doi:10.1016/j.cattod.2006.07.006.
Hu, Jianli, Wang, Yong, Cao, Chunshe, Elliott, Douglas C., Stevens, Don J., & White, James F. Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates Using Supported Rh Catalysts in a Microchannel Reactor. United States. doi:10.1016/j.cattod.2006.07.006.
Hu, Jianli, Wang, Yong, Cao, Chunshe, Elliott, Douglas C., Stevens, Don J., and White, James F. Mon . "Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates Using Supported Rh Catalysts in a Microchannel Reactor". United States. doi:10.1016/j.cattod.2006.07.006.
@article{osti_984247,
title = {Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates Using Supported Rh Catalysts in a Microchannel Reactor},
author = {Hu, Jianli and Wang, Yong and Cao, Chunshe and Elliott, Douglas C. and Stevens, Don J. and White, James F.},
abstractNote = {Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates Using Supported Rh Catalysts in a Microchannel Reactor},
doi = {10.1016/j.cattod.2006.07.006},
journal = {Catalysis Today, 120(1):90-95},
number = 1,
volume = 120,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Transition metal modified Rh-catalysts can be used for converting syngas (CO+H2) into C2+ oxygenates. It has been found that Mn has a favorable effect in the selectivity towards oxygenates, while addition of Ir to the binary Rh-Mn catalysts significantly increases the space-time yield of C2+ oxygenates. In this paper, we use quantum mechanical calculations to investigate the distribution of promoter sites within Rh rich nanoparticles and their role in the conversion of syngas towards ethanol. This work was supported by the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy Biomass Program. The Pacific Northwest National Laboratorymore » (PNNL) is operated by Battelle for the DOE under Contract DE-AC05-76RL01830. A portion of the research was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national science user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research located at PNNL.« less
  • In this study we report on a ZnxZryOz mixed oxide type catalyst capable of converting a syngas-derived C2+ mixed oxygenate feedstock to isobutene-rich olefins. Aqueous model feed comprising of ethanol, acetaldehyde, acetic acid, ethyl acetate, methanol, and propanol was used as representative liquid product derived from a Rh-based mixed oxygenate synthesis catalyst. Greater than 50% carbon yield to C3-C5 mixed olefins was demonstrated when operating at 400-450oC and 1 atm. In order to rationalize formation of the products observed feed components were individually evaluated. Major constituents of the feed mixture (ethanol, acetaldehyde, acetic acid, and ethyl acetate) were found tomore » produce isobutene-rich olefins. C-C coupling was also demonstrated for propanol feedstock - a minor constituent of the mixed oxygenate feed - producing branched C6 olefins, revealing scalability to alcohols higher than ethanol following an analogous reaction pathway. Using ethanol and propanol feed mixtures, cross-coupling reactions produced mixtures of C4, C5, and C6 branched olefins. The presence of H2 in the feed was found to facilitate hydrogenation of the ketone intermediates, thus producing straight chain olefins as byproducts. While activity loss from coking is observed complete catalyst regeneration is achieved by employing mild oxidation. For conversion of the mixed oxygenate feed a Zr/Zn ratio of 2.5 and a reaction temperature of 450oC provides the best balance of stability, activity, and selectivity. X-ray diffraction and scanning transmission electron microscopy analysis reveals the presence of primarily cubic phase ZrO2 and a minor amount of the monoclinic phase, with ZnO being highly dispersed in the lattice. The presence of ZnO appears to stabilize the cubic phase resulting in less monoclinic phase as the ZnO concentration increases. Infrared spectroscopy shows the mixed oxide acid sites are characterized as primarily Lewis type acidity. The direct relationship between isobutene production and the ratio of basic/acidic sites was demonstrated. An optimized balance of active sites for isobutene production from acetone was obtained with a basic/acidic site ratio of ~2. This technology for the conversion of aqueous mixtures of C2+ mixed oxygenates provides significant advantages over other presently studied catalysts in that its unique properties permit the utilization of a variety of feeds in a consistently selective manner.« less
  • The capability of a microchannel reactor for direct synthesis of dimethylether (DME) from biomass syngas was explored. The reactor was operated in conjunction with a hybrid catalyst system consisting of methanol synthesis and dehydration catalysts, and the influence of reaction parameters on syngas conversion was investigated. The activities of different dehydration catalysts were compared under DME synthesis conditions. Reaction temperature and pressure exhibited similar positive effects on DME formation. A catalytic stability test of the hybrid catalyst system was performed for 880 hours, during which CO conversion only decreased from 88% to 81%. In the microchannel reactor, the catalyst deactivationmore » rate appeared to be much slower than in a tubular fixed-bed reactor tested for comparison. Test results also indicated that the dehydration reaction rate and the water depletion rate via a water-gas-shift reaction should be compatible in order to achieve high selectivity to DME. Using the microchannel reactor, it was possible to achieve a space time yield almost three times higher than commercially demonstrated performance results. A side-by-side comparison indicated that the heat removal capability of the microchannel reactor was at least six times greater than that of a commercial slurry reactor under similar reaction conditions.« less