Steam reforming of pyrolysis oil using nickel-spinel based catalysis

Introduction – Rationale In many areas worldwide, electricity is mainly produced using fuelled generators or as a supplementary power source. The energy efficiency of those units is typically below 30% excluding production and distribution costs. Replacing the fossil fuels used in electricity production with biofuels will allow for lower carbon print, although the amount of biomass available may not be sufficient in arid areas such as the Canadian arctic. It is therefore necessary to reduce the consumption of the propellant by the unit. Fuel cells, which reach an efficiency of 65%, reduce the amount of fuel required by half. Fuel cells do not use liquid fuels directly, but rather a reformer is included to the device to reform the biofuel into syngas or hydrogen-rich syngas. The challenge with reforming complex molecules into syngas lies with carbon deposition. For example, Chen et al.1 tested the La1-xKxMnO3 catalyst, while Xing et al.2 performed catalysis of Co, Ni and Rh over MgAl2O4 for steam reforming of pyrolytic oil from vegetal and both observed carbon deposition. This work focuses on the steam reforming of pyrolytic oils originating from plastic and vegetal materials as biofuels. A comparison is drawn between the behavior of (a) a nickel-alumina spinel catalyst mixed with yttrium oxide stabilized zirconia (YSZ), and (b) a catalyst made of mine wastes (known as UGS), impregnated with nickel. The NiAl2O4-YSZ catalyst used in this study has already been tested for steam reforming of diesel3-5 and other liquid hydrocarbons6 and dry reforming of methane7-8 while the Ni-UGS catalyst has been tested for dry and steam reforming of methane9. Please click Additional Files below to see the full abstract

Aspects cinétiques de l'hydrolyse acide de la cellulose : présence d'oligomères solubles lors de la liquéfaction

Le monde scientifique développe un effort considérable pour que l'homme s'assure de nouvelles sources renouvelables de matières premières. Ceci est imposé par l'augmentation continue du taux d'industrialisation de notre société qui exige davantage des matières premières tout en préservant un environnement propre et productif. Notre travail fût conçu et exécuté dans le cadre de cette vision globale. Ses ambitions consistent à la présentation d'une nouvelle approche au traitement de la biomasse qui, éventuellement permettra son exploitation en vue de l'obtention de matières premières. L'objectif du travail est la "désaggrégation ordonnée et sélective" d'une macromolécule naturelle, i.e. la cellulose, afin d'obtenir des "fragments solubles" qui puissent être, par la suite, valorisés par voies biotechnologiques. Les "fragments solubles" devront être constitués d'un ensemble de polymères, oligomères et monomères ayant les mêmes qualités chimiques et structurelles (i.e. dérivés du glucose) de façon à faciliter leur reconnaissance et valorisation ultérieures par des enzymes, des micro­ organismes ou même des catalyseurs thermo-chimiques

Aspects cinétiques de l'hydrolyse acide de la cellulose : présence d'oligomères solubles lors de la liquéfaction

Le monde scientifique développe un effort considérable pour que l'homme s'assure de nouvelles sources renouvelables de matières premières. Ceci est imposé par l'augmentation continue du taux d'industrialisation de notre société qui exige davantage des matières premières tout en préservant un environnement propre et productif. Notre travail fût conçu et exécuté dans le cadre de cette vision globale. Ses ambitions consistent à la présentation d'une nouvelle approche au traitement de la biomasse qui, éventuellement permettra son exploitation en vue de l'obtention de matières premières. L'objectif du travail est la "désaggrégation ordonnée et sélective" d'une macromolécule naturelle, i.e. la cellulose, afin d'obtenir des "fragments solubles" qui puissent être, par la suite, valorisés par voies biotechnologiques. Les "fragments solubles" devront être constitués d'un ensemble de polymères, oligomères et monomères ayant les mêmes qualités chimiques et structurelles (i.e. dérivés du glucose) de façon à faciliter leur reconnaissance et valorisation ultérieures par des enzymes, des micro­ organismes ou même des catalyseurs thermo-chimiques

The ‘Green’ Ni-UGSO Catalyst for Hydrogen Production under Various Reforming Regimes

A new spinelized Ni catalyst (Ni-UGSO) using Ni(NO3)2·6H2O as the Ni precursor was prepared according to a less material intensive protocol. The support of this catalyst is a negative-value mining residue, UpGraded Slag Oxide (UGSO), produced from a TiO2 slag production unit. Applied to dry reforming of methane (DRM) at atmospheric pressure, T = 810 °C, space velocity of 3400 mL/(h·g) and molar CO2/CH4 = 1.2, Ni-UGSO gives a stable over 168 h time-on-stream methane conversion of 92%. In this DRM reaction optimization study: (1) the best performance is obtained with the 10–13 wt% Ni load; (2) the Ni-UGSO catalysts obtained from two different batches of UGSO demonstrated equivalent performances despite their slight differences in composition; (3) the sulfur-poisoning resistance study shows that at up to 5.5 ppm no Ni-UGSO deactivation is observed. In steam reforming of methane (SRM), Ni-UGSO was tested at 900 °C and a molar ratio of H2O/CH4 = 1.7. In this experimental range, CH4 conversion rapidly reached 98% and remained stable over 168 h time-on-stream (TOS). The same stability is observed for H2 and CO yields, at around 92% and 91%, respectively, while H2/CO was close to 3. In mixed (dry and steam) methane reforming using a ratio of H2O/CH4 = 0.15 and CO2/CH4 = 0.97 for 74 h and three reaction temperature levels (828 °C, 847 °C and 896 °C), CH4 conversion remains stable; 80% at 828 °C (26 h), 85% at 847 °C (24 h) and 95% at 896 °C (24 h). All gaseous streams have been analyzed by gas chromatography. Both fresh and used catalysts are analyzed by scanning electron microscopy-electron dispersive X-ray spectroscopy (SEM-EDXS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) coupled with mass spectroscopy (MS) and BET Specific surface. In the reducing environment of reforming, such catalytic activity is mainly attributed to (a) alloys such as FeNi, FeNi3 and Fe3Ni2 (reduction of NiFe2O4, FeNiAlO4) and (b) to the solid solution NiO-MgO. The latter is characterized by a molecular distribution of the catalytically active Ni phase while offering an environment that prevents C deposition due to its alkalinity

Recent Advances in the Decontamination and Upgrading of Waste Plastic Pyrolysis Products: An Overview

Extensive research on the production of energy and valuable materials from plastic waste using pyrolysis has been widely conducted during recent years. Succeeding in demonstrating the sustainability of this technology economically and technologically at an industrial scale is a great challenge. In most cases, crude pyrolysis products cannot be used directly for several reasons, including the presence of contaminants. This is confirmed by recent studies, using advanced characterization techniques such as two-dimensional gas chromatography. Thus, to overcome these limitations, post-treatment methods, such as dechlorination, distillation, catalytic upgrading and hydroprocessing, are required. Moreover, the integration of pyrolysis units into conventional refineries is only possible if the waste plastic is pre-treated, which involves sorting, washing and dehalogenation. The different studies examined in this review showed that the distillation of plastic pyrolysis oil allows the control of the carbon distribution of different fractions. The hydroprocessing of pyrolytic oil gives promising results in terms of reducing contaminants, such as chlorine, by one order of magnitude. Recent developments in plastic waste and pyrolysis product characterization methods are also reported in this review. The application of pyrolysis for energy generation or added-value material production determines the economic sustainability of the process

Catalytic pyrolysis of high-density polyethylene for the production of carbon nanomaterials: effect of pyrolysis temperature

A two-stage reaction process is followed to convert high-density polyethylene (HDPE) into carbon nanofilaments (CNFs) and hydrogen-rich gas. The experiments are performed in a continuous mode in a two-stage quartz reactor: thermal pyrolysis of HDPE followed by the catalytic decomposition of the pyrolysis gases over a nickel catalyst prepared from mining residues. To examine the effect of the pyrolysis temperature on the yield and quality of the final products, two steps were followed. First, non-catalytic pyrolysis experiments were run at different temperatures (600, 650, and 700 °C), and the products were examined. Second, pyrolysis–catalysis experiments were performed at the same pyrolysis temperatures and a fixed catalytic temperature (600 °C) to examine the CNF and hydrogen yields. The results showed that the production of carbon nanomaterials (CNMs) and H2 is optimal at 650 °C, with yields of 70.8 and 38.0 wt%, respectively. Scanning electron microscopy (SEM) revealed the presence of carbon filaments with different diameters and lengths at the three different temperatures. Moreover, thermogravimetric analysis (TGA) confirmed that the produced carbon is filamentous, with the presence of amorphous carbon at 700 °C