Wasteomics ⇒ a workflow to analyze complex reaction environments, waste, and realistic feeds conversions



Problem statement

In most heterogeneous catalytic processes, the reactive environment contains a mixture of reactants, intermediates, and products, and some adsorbed-trapped on the catalytic surface and elsewhere. Thus, most reacting environments in catalysis are complex, involve several phases (multiphase), and comprise unstable species or are challenging to analyze. To make things worse, some of these species have (auto-)catalytic or deactivating nature on the kinetics of the surrounding ones.

A typical practice in catalysis is using model molecules or surrogates to deepen into the mechanistic pathways, microkinetics, spectroscopy, etc. Conversely, analytical techniques keep evolving, becoming more precise but always targeting a specific fraction or type of species. That is to say, there is only one technique that solves all.

We aim to bridge the fundamental research performed in our group and outside using model molecules with a powerful analytical multi-technique approach to analyze the entire reaction media. The -omics fields inspire us to reflect on the collective characterization and quantification of pools of molecules that translate into the structure, function, and dynamics involved. We apply our approach to hydrocarbon transformations and green-sustainable feedstock (i.e., waste plastics, sewage sludge, biomass, algae, and seaweed). We develop multi-technique analytical protocols for the complete chemical molecular-level description of complex mixtures.

Goals

  • Analytical workflow ⇒ multi-analytical technique integration
  • Wasteometrics I ⇒ quantitative- and molecular-level analysis
  • Wasteometrics II ⇒ data mining and processing
  • Wasteomics ⇒ reaction networks and kinetic modeling

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Related Publications

Monitoring Ni0 and Coke Evolution during the Deactivation of a Ni/La2O3-alpha-Al2O3 Catalyst in Ethanol Steam Reforming in a Fluidized Bed

by Montero, Ochoa, Castaño, Bilbao, Gayubo
J. Catal. Year: 2015

Abstract

This work studies the mechanism of coke deactivation of a Ni/La2O3–αAl2O3 catalyst in ethanol steam reforming conducted in a fluidized bed reactor under conditions of severe deactivation, at 500 °C. Deactivation takes place in three consecutive stages with time on stream, corresponding to increasing values of ethanol concentration in the reaction system and decreasing values for CH4 and CO byproducts. The analysis of the nature of coke by means of several techniques in the different deactivation stages shows that high conversion values (low ethanol concentrations in the medium) give way to filamentous coke (with CO and CH4 as precursor), which has little effect on deactivation. For a highly deactivated catalyst, ethanol concentration is high, and a nonfilamentous deactivating coke is formed (mainly due to the evolution of filamentous coke). X-ray diffraction analysis of Ni particles in different deactivation states shows that a fraction of Ni crystallites are dragged by filamentous coke and the fraction of Ni crystallites that remain supported are blocked by nonfilamentous coke. A scheme has been established to explain the evolution of Ni and coke, the interaction between both dynamics, and its effect on catalyst deactivation.

Keywords

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