Stable Steam Reforming of Ethanol in a Two-Zone Fluidized-Bed Reactor

Abstract

The oxidative steam reforming of ethanol in a two-zone fluidized-bed reactor (TZFBR) and in a conventional fluidized-bed reactor over a Ni/Al 2 O 3 catalyst has been investigated. Catalyst deactivation has been studied for both contact modes. Coke generation has been verified by several techniques, and a stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The effects of the main operating variables (steam/ethanol ratio S/E, oxygen/ethanol ratio O/E, temperature, and relative velocity with respect to the minimum fluidization velocity) have been studied. Both stable results and continuous operation without catalyst deactivation were achieved in the TZFBR in a wide range of S/E values, showing its viability for carrying out this process. High hydrogen selectivity with total conversion of ethanol was achieved even at low S/E and O/E ratios.

Catalytic Dehydration of Glycerol to Acrolein in a Two-Zone Fluidized Bed Reactor

“…Thus, two zones can be distinguished: the bottom zone, where the catalyst is only in contact with the regenerating agent, and the top zone, where the catalyst is in contact with the reactant gas. The corresponding concept—called Two-Zone Fluidized-Bed Reactor (TZFBR)—was applied for regeneration of an ethanol-reforming coked catalyst, (Pérez-Moreno et al, 2012) but also and mainly for decoupling the oxidation and reduction steps of catalyzed reactions following a Mars and Van Krevelen mechanism [i.e., styrene synthesis, (Cocco and Castor, 2001) oxidative dehydrogenation of butane and propane] (Soler et al, 1999; Gascón et al, 2005; Lobera et al, 2009).…”

Advances and trends in two-zone fluidized-bed reactors

“…It is obvious that the operation with high steam/ethanol ratios implies a high energy consumption to produce steam, and if water should be transported that would mean an additional expense. We have shown [18] that steam reforming of ethanol can be performed under operating conditions that would cause coke formation in a conventional reactor, by using a TZFBR. This application is quite similar to the methane steam reforming previously shown.…”

Use of α -shapes for the measurement of 3D bubbles in fluidized beds from two-fluid model simulations

“…This expression, which has already been used in previous studies [24,31,35], weights bubble diameters proportionally to their size. The use of the weighted average d b is motivated by the fact that big bubbles are more representative of the bubbling gas flow than small spurious bubbles.…”

“…the catalyst circulation, between the two zones allows the process integration [30]. The performance of this kind of reactor arrangement has been successfully tested in many processes such as: light alkane dehydrogenations, ethanol steam reforming or methane aromatization [31][32][33]. Its fluid dynamic characteristics have also been extensively studied both experimentally and with TFM simulations on pseudo-2D reactor geometries [24,[34][35][36][37].…”