The kinetic and experimental study for the syngas production from ethanol dry reforming over a Ni‐Cu / La ₂ O ₃ catalyst

Abstract

Summary The mechanistic kinetic model through Langmuir‐Hinshelwood (LH) isotherm was derived for ethanol dry reforming (EDR) processaccompanied by the ethanol decomposition (ED) and methane dry reforming (MDR). For justifying mechanistic relation, EDR tests wereaccomplished under a vast range of operating variables (including temperature varied from 500°C to 900°C and ratio of CO2 to C2H5OH in the inlet feed [C/E ratio] of 1‐3) over a Ni‐Cu/La2O3 catalyst. The physicochemical properties of the fresh and spent catalysts were investigated via inductively coupled plasma atomic emission spectrometer (ICP‐AES), X‐ray diffractometer (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), temperature programmed reduction (TPR), and N2 adsorption/desorption tests. The ethanol conversion near to 100% was obtained at 850°C and a C/E ratio of 1, and no obvious deactivation was observed up to 800 min initial on stream. The estimation procedure of kinetic parameters was conducted via nonlinear least square regression to correlate between rate and equilibrium constants in terms of temperature via Arrhenius and van't Hoff equations, respectively. The error of the kinetic model was measured as 11.92% and predicted ethanol conversion with higher precision than other responses. The ethanol conversion and H2 yield higher than 90% achieved beyond 800°C regardless of the C/E ratio. A maximum point was located at 700°C for CO2 conversion trend vs the temperature. An increase in the C/E ratio resulted in ethanol conversion and CO yield, while trends of the CO2 conversion and H2 yield passed from a maximum point. H2 yield 93.45% was obtained at 800°C and a C/E ratio of 1.5 in presence of Ni‐Cu/La2O3 catalyst, which was bigger than reported values by various scientists.

Reforming of ethanol with carbon dioxide catalysed by silver-promoted copper–ceria–zirconia composites

“…18 In the present study acetaldehyde was not observed while it is often observed or stated in the literature. 1–26 After hydrogen is eliminated from structure (B), successive rapid reactions including structures (C), (D), (E) and (A) in order could occur. In the structure (C), methyl, carbonyl and hydride groups are formed on the surface through C–C bond scission and C–H bond scission of adsorbed acetaldehyde on Cu I species.…”

“…Dry reforming using greenhouse gas CO 2 to produce hydrogen and synthesis gas could be an ideal process if carbon neutral biomass was combined. 1–26 Although dry reforming of methane, one of the fossil fuels, has already been developed extensively, 27–37 the continuous utilization of fossil fuels might increase CO 2 even if methane fermentation could be utilized. Instead of the use of methane, dry reforming of ethanol (DRE) 1–26 would be one of the promising attempts to achieve a complete carbon neutral system.…”

“…1–26 Although dry reforming of methane, one of the fossil fuels, has already been developed extensively, 27–37 the continuous utilization of fossil fuels might increase CO 2 even if methane fermentation could be utilized. Instead of the use of methane, dry reforming of ethanol (DRE) 1–26 would be one of the promising attempts to achieve a complete carbon neutral system. 1 Ethanol is a common product, not toxic, safely preserved, transferred, treated and further could be a very attractive hydrogen source.…”

“…Nevertheless, DRE has still been desired since syngas with a H 2 /CO ratio of 1 suitable for hydrocarbon production in the Fischer–Tropsch reaction could be produced. When this reaction has been performed, 1–26 however, yields of H 2 and CO were not necessarily high due to not only methane formation but also coke deposition at a temperature higher than 600 °C. It was reported that Cu-based catalysts showed higher ethanol and CO 2 conversions in dry reforming.…”