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Résumé :
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Microchannel reactors offer the intensification of heat transfer to endothermic chemical reactions. Microchannel reactors consist of a parallel array of micron-scale channels that are integrated into one device using microfabrication techniques. The gasification of glucose by supercritical water was studied in a stainless-steel microchannel reactor at 250 bar and 650−750 °C. The microchannel reactor architecture consisted of a parallel array of 21 rectangular microchannels (75 µm × 500 µm), each of 100 cm length, that were packaged into a serpentine pattern of 25 layers. At 750 °C, glucose was completely converted to gas products within a 2.0 s residence time, yielding an average gas composition of 53% H2, 35% CO2, 10% CH4, and 0.5% CO and a H2 yield of 5.7 ± 0.3 mol H2/mol glucose. At 650 °C, the intermediate products from the decomposition of glucose prior to their gasification and reforming were characterized. Routes for glucose transformation included the decomposition to acetic and propanoic acids, acid-catalyzed dehydration to 5-hydroxymethylfurfural and 2,5-hexanedione, and conversion to phenol. This study has shown that microchannel reactors have considerable promise for intensifying the thermochemical conversion of biomass constituents to useful chemicals and fuels.
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