Suchergebnisse

4 figures, 2 tables.-- Supplementary information. ; The production of upgraded bio-oils by an integrated process using a mixture of calcined limestone and sand as a heat carrier with catalytic properties was experimentally studied at pilot scale. The integrated process consisted of two main steps: biomass catalytic pyrolysis in an Auger reactor for bio-oil production and char combustion in a fluidised-bed combustor for heat carrier heating and regeneration. A temperature of 450 °C was fixed as an optimum value to carry out the catalytic pyrolysis step. Temperatures ranging from 700 to 800 °C were assessed in the char combustor. Process simulation demonstrated that solid recirculation from the combustor to the pyrolysis reactor was marginally affected in this temperature range. However, an optimum char combustion temperature of 800 °C was selected from an environmental point of view, since lower polyaromatic emissions were detected whilst NOx emissions were kept under the legislation limits. Under designated conditions, several pyrolysis-combustion cycles were carried out. A moderate deactivation of the catalyst by partial carbonation was found. This fact makes necessary the incorporation of a purge and an inlet of fresh heat carrier in order to maintain the bio-oil quality in the integrated process. ; Authors thank to Spanish MINECO and European Union FEDER funds for providing support for this work (projects CTQ2012-37984-C02-01 and ENE2015-68320-R). ; Peer reviewed

14 figures, 4 tables. ; Sorption-enhanced methanation (SEM) is one of the solutions proposed for the production of high quality synthetic natural gas (SNG) under mild conditions of temperature and pressure. In this novel process, the methanation reaction is performed in the presence of an adsorbent that retains the water produced as by-product. The SEM potential of a Rh-based catalyst and a zeolite 5A adsorbent has been demonstrated for both CO and CO2 hydrogenation. Pure CH4 production was possible operating at 275 °C and atmospheric pressure under sorption-enhanced CO2 methanation conditions for space velocities of up to 514 mlCO2/gcat/h. For sorption-enhanced CO methanation, CH4 purities of 86 vol% were achieved under the same operating conditions but at lower space velocity (440 mlCO/gcat/h). Finally, SEM/regeneration cycles were performed for a feed gas containing CO and CO2, achieving stable performance throughout the cycles and a constant CH4 purity of about 60 vol% for the operating conditions chosen. ; Authors acknowledge the project RTI2018-095575-B-I00 funded by MCIN/AEI/10.13039/501100011033/ and "ERDF A way of making Europe" and the Regional Government of Aragon (DGA) under the research groups support programme. Laura Gómez also thanks the DGA for her pre-doctoral fellowship. Isabel Martínez thanks the grant RYC2019-026929-I funded by MCIN/AEI/10.13039/501100011033 and "ESF Investing in your future". ; Peer reviewed

The operational limits of a commercial nickel-based catalyst under the conditions of a sorption-enhanced steam-methane reforming process coupled to a Ca/Cu chemical loop are investigated for high-purity H2 production in a cyclic operation. The performance of the reforming catalyst is tested by means of a high number of oxidation-reduction-reforming cycles. After 100 oxidation-reduction cycles, this catalyst retains its exceptional reforming activity. The methane conversion values are close to the thermodynamic equilibrium under very demanding conditions: temperature between 500 ºC - 700 ºC and mass hourly space velocity of 8.8 kgCH4 h-1 kgcat-1. After 200 cycles, the sample shows reduction in its reforming activity in line with a lower dispersion of the Ni species. Sintering of Ni nanocrystals is evidenced during the oxidation-reduction multi-cycles. The performance of the catalyst after 200 oxidation-reduction cycles mixed with a CaO-based CO2 sorbent is studied under optimal conditions calculated for the sorption-enhanced reforming process coupled to a Ca/Cu cycle (temperature of 650 ºC, steam/methane ratio of 4, sorbent/catalyst ratio of 4 and space velocity of 0.75 kgCH4 h-1 kgcat-1). Remarkably, an equilibrium value over 92 vol.% H2 concentration is achieved, highlighting this catalyst as a promising candidate for the next steps of the process development. ; The authors acknowledge support received from the European Union Seventh Framework Programme FP7 under grant agreement No. 608512 (ASCENT Project) and the Regional Government of Aragon (DGA) under the research groups support programme. The authors wish to thank J.M. Pardo for participating in the experimental work. ; Peer reviewed

4 Figuras.- 7 Tablas.- Material suplementario disponible en línea en http://www.mdpi.com/2073-4344/9/12/992/s1 ; The catalytic co-pyrolysis of grape seeds and waste tyres for the production of high-quality bio-oils was studied in a pilot-scale Auger reactor using different low-cost Ca-based catalysts. All the products of the process (solid, liquid, and gas) were comprehensively analysed. The results demonstrate that this upgrading strategy is suitable for the production of better-quality bio-oils with major potential for use as drop-in fuels. Although very good results were obtained regardless of the nature of the Ca-based catalyst, the best results were achieved using a high-purity CaO obtained from the calcination of natural limestone at 900 °C. Specifically, by adding 20 wt% waste tyres and using a feedstock to CaO mass ratio of 2:1, a practically deoxygenated bio-oil (0.5 wt% of oxygen content) was obtained with a significant heating value of 41.7 MJ/kg, confirming its potential for use in energy applications. The total basicity of the catalyst and the presence of a pure CaO crystalline phase with marginal impurities seem to be key parameters facilitating the prevalence of aromatisation and hydrodeoxygenation routes over the de-acidification and deoxygenation of the vapours through ketonisation and esterification reactions, leading to a highly aromatic biofuel. In addition, owing to the CO2-capture effect inherent to these catalysts, a more environmentally friendly gas product was produced, comprising H2 and CH4 as the main components. ; This research was funded by MINECO and FEDER for their financial support (Project ENE2015-68320-R) and the Regional Government of Aragon (DGA) under the research groups call. ; Peer reviewed

The development of rapid and accurate techniques to predict the composition of crude bio-oils obtained via the pyrolysis of lignocellulosic biomass is a prerequisite for their industrial implementation. Here, we demonstrate the potential of the Fourier Transform Infrared Spectroscopy to replace the gas chromatography-mass spectrometry (GC-MS) in determining the compositional groups of bio-oils. Using mid-infrared spectroscopic technique as predictor, chemometric tools based on partial least squares regression models were contrasted with GC-MS results to foresee the various families of organic compounds. A broad data set, consisting of more than one hundred samples obtained from the thermal and catalytic pyrolysis of woody biomass and from the upgrading of bio-oil vapors by catalytic cracking over zeolites and metal oxides was used. The applicability of the developed model was assessed by external validation using the Kennard-Stone algorithm, showing that more than 90 wt% of the bio-oil composition was accurately determined. These results pave the path for the on-line monitoring of the forthcoming manufacture system of second-generation biofuels through rapid and costeffective characterization of the pyrolysis bio-oils, thus enabling industrial producers to make timely decisions. ; Authors would like to thank the Spanish MINECO and European Union FEDER funds for providing support for this work (projects CTQ2012-37984-C02-01 and ENE2015- 68320-R). B.P. thanks the Spanish Ministry of Education through the Temporary Transfer Program (TRA13/00003). ; Peer reviewed

9 pages, 6 figures, 3 tables.--Available online 8 December 2013 ; Co-pyrolysis of forestry wastes and waste tyres is carried out using different facilities: a fixed bed reactor and a continuous auger reactor. Remarkably, only one phase is found in the liquid fraction, which is not achieved by mixture of the pure liquids. In addition, positive effects between waste tyre and biomass are evidenced, being more notable even synergetic in the auger reactor. It is found that whilst acidity, density and oxygen content decrease, pH and calorific value increase with respect to the merely biomass pyrolysis liquid, leading to upgraded bio-oil. Upgrading process is linked to the presence of radical interactions between waste tyres and biomass pyrolysis products. In addition, it is observed that the addition of waste tyres to the feedstock blend is significantly decreasing the amount of aldehydes and phenolic compounds, which is beneficial for improving the stability of the new bio-oils. © 2013 Elsevier B.V. ; The authors would like to thank the Aragon Regional Government (DGA) and the Caixa Bank for financial support (Project GA-LC-015/ 2011). The authors also thank MINECO and FEDER funds for providing partial support for this work (project CTQ2012-37984-C02-01). Juan D. Martínez thanks the Fundación Carolina for his fellowship as well as the Enlaza-Mundos Program. Part of the research carried out at UAB has been funded by MICINN (CTQ2009-13873). ; Peer Reviewed