Fernando Mariño

Bio-ethanol steam reforming on Ni/Al2O3 catalyst

In this work, the ethanol steam reforming on Ni/γAl2O3 catalyst at temperatures between 573 and 773 K was studied and an overall reaction scheme as a function of temperature was proposed. It can be concluded that higher water/ethanol ratio (6:1) and higher temperature (773 K) promote hydrogen production (91% selectivity). Over Ni-based catalyst there would not be evidences that water gas shift reaction occurs. The presence of oxygen in the feed produces a favorable effect on carbon deposition; nevertheless the carbon monoxide production is not reduced.

Hydrogen production from steam reforming of bioethanol using Cu/Ni/K/γ-Al2O3 catalysts. Effect of Ni

Hydrogen to be used as a raw material in fuel cells or even as a direct fuel can be obtained from steam reforming of bioethanol. The key aim of this process is to maximize hydrogen production, discouraging at the same time those reactions leading to undesirable products, such as methane, acetaldehyde, diethyl ether or acetic acid, that compete with H2 for the hydrogen atoms. Cu–Ni–K/γ-Al2O3 catalysts are suitable for this reaction since they are able to produce acceptable amounts of hydrogen working at atmospheric pressure and a temperature of 300°C. The effect of nickel content in the catalyst on the steam-reforming reaction was analyzed. Nickel addition enhances ethanol gasification, increasing the gas yield and reducing acetaldehyde and acetic acid production.

Hydrogen from steam reforming of ethanol. characterization and performance of copper-nickel supported catalysts

Abstract The effect of the copper loading and calcination temperature on the structure and performance of Cu/Ni|K|γ-Al2O3 catalysts is examined. TPR, XRD and N2O chemisorption techniques are employed. Activity and selectivity measurements are carried out considering steam reforming of ethanol as the test reaction. The appearance of CuO phase depends on copper loading and calcination temperature, whereas NiAl2O4 phase is present in all the analyzed samples. Copper dispersion is favored at lower copper loading. TOF values indicate that steam reforming of ethanol should be a structure-sensitivity reaction, at least under the experimental conditions used in this work.

Hydrogen production via catalytic gasification of ethanol. A mechanism proposal over copper–nickel catalysts

Ethanol gasification using Cu–Ni–K/γ-Al2O3 catalysts was studied. The reaction was carried out at a low temperature (300°C) and atmospheric pressure. The influence of the diffusional effects, the residence time and the water/ethanol molar ratio in the feed on the ethanol conversion and on the product distribution was analysed. Additional experiments were performed with monometallic catalysts, such as Cu–K/γ-Al2O3 and Ni–K/γ-Al2O3 catalysts. Ethanol gasification is favoured by a diminution of the diffusional resistances, high residence time and low water to ethanol feed ratio. A probable reaction mechanism is postulated, which is consistent with the experimental results and let identify the function of each metal (copper and nickel).

Simulation of CO Preferential Oxidation (COPrOx) Monolithic Reactors

Abstract In this work, a COPrOx monolithic reactor with a CuO/CeO2/Al2O3 catalytic washcoat was modelled to purify a H2 stream for a 2 kW PEM fuel cell. Preliminary simulations included isothermal monoliths operating between 423 and 463 K, and the optimization of linear axial temperature profiles. For a fixed total system size and a desired CO outlet molar fraction lower than 20 ppm, an isothermal temperature profile maximized the global selectivity towards CO oxidation. Then, different schemes of adiabatic monoliths with interstage cooling were modelled and evaluated. It was found that wide operating temperature ranges lower the necessary number of stages, but decrease the global selectivity and rise system sensitivity to inlet temperatures. A 1D heterogeneous model was used to simulate the monoliths.

Steam reforming of ethanol using Cu-Ni supported catalysts

The effect of calcination temperature (450–800°C) and copper loading (lower and higher than 4wt%) on the catalytic behaviour and structure of Cu/Ni/K//γ-Al 2 O 3 catalysts were analysed. These catalysts were proven to be suitable for the steam reforming of ethanol. XPS, SEM-EDX, XRD and N 2 O chemisorption techniques were employed; catalytic activity is evaluated using the steam reforming of ethanol as the test reaction. Depending of both, copper loading and calcination temperature, a non-stoichiometric surface spinel can be obtained which has catalytic properties. The presence of a layered double hydroxide precursor is essential for the formation of this phase.

Nickel-based doped ceria-supported catalysts for steam reforming of methane at mild conditions

ABSTRACT Hydrogen is widely considered a promising green energy vector. It may be produced by steam reforming of methane which may be obtained from renewable resources such as biogas or biomass gasification. Nickel catalysts supported in ceria oxides doped with La, Pr, or Zr were used. Catalysts were prepared by wet impregnation of supports previously obtained by coprecipitation using the urea method and subsequent calcination at 600ºC. Solids were then characterized by Brunauer–Emmett–Teller, X-Ray iffraction, and oxygen storage capacity/oxygen storage capacity complete measurements. Catalysts have shown both effectiveness and stability in methane steam reforming reaction at 600ºC with a steam/methane ratio close to the stoichiometric.