Control of steam input to the pyrolysis-gasification of waste plastics for improved production of hydrogen or carbon nanotubes

Carbon nanotubes (CNTs) have been proven to be possible as high-value by-products of hydrogen production from gasification of waste plastics. In this work, steam content in the gasification process was investigated to increase the quality of CNTs in terms of purity. Three different plastics-low density polyethylene (LDPE), polypropylene (PP) and polystyrene (PS) were studied in a two stage pyrolysis-gasification reactor. Plastics samples were pyrolysed in nitrogen at 600°C, before the evolved gases were passed to a second stage where steam was injected and the gases were reformed at 800°C in the presence of a nickel-alumina catalyst. To investigate the effect that steam plays on CNT production, steam injection rates of 0, 0.25, 1.90 and 4.74gh-1 were employed. The CNTs produced from all three plastics were multiwalled CNTs with diameters between 10 and 20nm and several microns in length. For all the plastic samples, raising the steam injection rate led to increased hydrogen production as steam reforming and gasification of deposited carbon increased. High quality CNTs, as observed from TEM, TPO and Raman spectroscopy, were produced by controlling the steam injection rate. The largest yield for LDPE was obtained at 0gh-1 steam injection rate, whilst PP and PS gave their largest yields at 0.25gh-1. Overall the largest CNT yield was obtained for PS at 0.25gh-1, with a conversion rate of plastic to CNTs of 32wt%

Les inhibiteurs des tyrosine kinases (une nouvelle classe de médicaments anticancéreux)

AIX-MARSEILLE2-BU Pharmacie (130552105) / SudocSudocFranceF

Production d'hydrogène par vaporeformage de l'éthanol (application aux piles à combustible)

Ce travail concerne l'étude de la production embarquée d'hydrogène par vaporeformage catalytique de l'éthanol en vue d'alimenter une pile à combustible. Les performances de divers métaux (Rh, Pt, Pd, Ru, Ni, Cu, Zn, Fe) supportés sur des oxydes (Al2O3, CeO2, CeZrO2, ZrO2, CeO2-Al2O3, NixMg1-xAl2O4, MgO), dans le vaporeformage de l'éthanol à pression atmosphérique et sous moyenne pression, ont été évaluées. La nature du métal et son état de dispersion jouent un rôle prépondérant sur l'activité des catalyseurs. La nature du support conditionne également l'activite , la sélectivité et la stabilité des catalyseurs. Du point de vue de l'activité, le support doit présenter une bonne hydrophilicité (activation de l'eau) et les groupes hydroxyles de surface doivent être fortement mobiles. Le contrôle de l'acido-basicité permet, initialement, d'orienter préférentiellement la réaction vers la formation d'éthylène (C2H4) ou d'acétaldéhyde (CH3CHO) et d'influer sur la sélectivité et la stabilité du catalyseur.This work was devoted to the study of the ethanol catalytic steam reforming reaction for the on-board hydrogen production for fuel cells. The performances of various metals (Rh, Pt, Pd, Ru, Ni, Cu, Zn, Fe) supported on oxides (Al2O3, CeO2, CeZrO2, ZrO2, CeO2-Al2O3, NixMg1-xAl2O4, MgO), in the ethanol steam reforming reaction carried out at atmospheric and intermediate pressure, was checked. The nature of the metal and the dispersion play an important role on the activity of the catalyst. The nature of the support conditions the activity, the selectivity and the stability of the catalysts. From the activity point of view, the support must exhibit a good hydrophilicity (water activation) and the surface hydroxyls groups should be strongly mobile. The control of acid-base properties allows to initially direct the reaction preferentially towards the formation of ethylene (C2H4) or of acetaldehyde (CH3CHO) and to influence the selectivity and the stability of the catalyst.POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Le vaporeformage catalytique : un vieux procédé pour une solution nouvelle...

SSCI-VIDE+CARE+CDSNational audienceNon

Bio-ethanol steam reforming on supported metal catalysts

SSCI-VIDE+CARE+CDSInternational audienceNon

Bio-ethanol catalytic steam reforming over supported metal catalysts

SSCI-VIDE+CARE+CDSInternational audienceConsidering both the influence of the nature of the metal (Rh, Pt, Ni, Cu, Zn, Fe) and the role of the support (gamma-Al2O3, 12%CeO2-Al2O3, CeO2, Ce0.63Zr0.37O2), CO2 is presented as a primary product in the bio-ethanol steam-reforming catalytic reaction (SRR) over some supported metal catalysts. Based on this unexpected observation, a new strategy for maximizing the hydrogen production and minimizing the CO formation is proposed. Any highly selective catalytic formulation should be free of any promoter in the water gas shift reaction (WGSR) which tends to equilibrate the SRR gas towards higher CO concentrations. (C) 2002 Elsevier Science B.V. All rights reserved

H2 production from bio-ethanol via catalytic steam reforming

SSCI-VIDE+CARE+CDSInternational audienceNon

Hydrogen production for fuel cells from the catalytic ethanol steam reforming

SSCI-VIDE+CARE+CDSInternational audienceNon

Production d'hydrogène par vaporeformage de l'ethanol

SSCI-VIDE+CARE+CDSNational audienceNon

Hydrogen production for fuel cells from the catalytic ethanol steam reforming

SSCI-VIDE+CARE+CDSInternational audienceNon