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Jacques Lédé - One of the best experts on this subject based on the ideXlab platform.

  • Pyrolysis and Gasification of Biomass in Solar and Simulated Solar Environments: The Pioneering Works of Michael J. Antal in the Period of 1976–1989
    Energy & Fuels, 2016
    Co-Authors: Jacques Lédé
    Abstract:

    The present paper summarizes the main works that Michael J. Antal performed between 1976 and 1989 in the field of biomass conversion under the influence of Concentrated Radiation. Both solar furnaces and solar simulators have been used. The experiments and modelings (pyrolysis and gasification) have been made under a great number of conditions (types of biomasses, reactors, etc.). The numerous results include new insights in the best knowledge of radiant reactors and fundamental general aspects of biomass gasification and fast pyrolysis. Two other types of reactions carried out in solar simulators are also described in this review. More than 30 years later, many of these pioneering works have unfortunately been forgotten. It is concluded that authors working in these topics would greatly benefit by examining the related works published by Michael J. Antal before starting new research programs.

  • The image furnace for studying thermal reactions involving solids. Application to wood pyrolysis and gasification, and vapours catalytic cracking
    Fuel, 2013
    Co-Authors: Olivier Authier, Jacques Lédé
    Abstract:

    The aim of the present paper is to show that the image furnace is an efficient laboratory device for studying fundamental aspects of high temperature reactions involving a solid. The basic principle relies of solid heating by a Concentrated Radiation in very clean conditions. The available heat flux densities can be quantitatively controlled inside very large domains, which are quite similar as those encountered in usual pilot plant reactors. The image furnace qualities are experimentally studied in the particular case of biomass thermal conversion. Many results have been already published in the field of pyrolysis reactions. The present paper reports its ability to study also basic reactions of char steam gasification and of catalytic (olivine) cracking of vapours produced by biomass thermal degradation. These three types of reactions (decomposition of a solid; reaction of a gas with a solid; interaction of a vapour with a catalyst) can be studied independently from each other and in the same heat flux densities conditions. The results can be efficiently used for further worthwhile modelling of biomass gasifiers.

  • Production of hydrogen by lignins fast pyrolysis
    International Journal of Hydrogen Energy, 2006
    Co-Authors: Sébastien Baumlin, Monique Ferrer, François Broust, Frédéric Bazer-bachi, Thomas Bourdeaux, Olivier Herbinet, Fatou Toutie Ndiaye, Jacques Lédé
    Abstract:

    This paper reports the results of experiments performed on the flash pyrolysis of lignin samples submitted to controlled heat flux densities (short flashes of a Concentrated Radiation). Two types of lignins are used: Kraft and Organocell lignins. Microscopic observations of the reacted samples reveal the formation of an intermediate liquid compound that precedes the further formation of char, vapours and gases. The rates of mass loss and the production rates of the products are determined for both lignins. The results are compared to each other and to those obtained in former similar studies made with cellulose. The analyses of the produced gases reveal high syngas and H2 contents (respectively 87 and 50 mol%). This composition is compared to results obtained in other different thermal conditions with lignins and other types of biomasses. The possible mechanism of hydrogen formation is further discussed.

  • Comparison of contact and radiant ablative pyrolysis of biomass
    Journal of Analytical and Applied Pyrolysis, 2003
    Co-Authors: Jacques Lédé
    Abstract:

    Abstract Ablation characterizes the phenomena occurring when a solid, submitted to a high external heat flux density, gives rise to solids, liquids and/or gases that can be rapidly and continuously eliminated. Ablation can be exploited for carrying out the fast pyrolysis of materials such as biomass. This paper describes and compares, on a fundamental point of view, two methods of biomass ablative pyrolysis. In the first one, biomass is pressed against a hot surface (contact ablative pyrolysis). In the second one, biomass intercepts a Concentrated Radiation (radiant ablative pyrolysis). The comparison is made on the basis of the values of ablation thickness and velocity (derived from experiments and modelling), and of product fractions and compositions. The results can be very different in spite of the fact that biomass may be subjected to similar heat flux densities in both cases. The paper shows the advantages, drawbacks and complementarities of each technology.

  • Flash pyrolysis of cellulose pellets submitted to a Concentrated Radiation: experiments and modelling
    Chemical Engineering Science, 2002
    Co-Authors: Olivier Boutin, Monique Ferrer, Jacques Lédé
    Abstract:

    Abstract The image furnace technology has been applied to the study of the first steps of biomass flash pyrolysis. The experiments performed with small pellets of cellulose show that the reaction primarily passes through the intermediate of short lifetime liquid species (ILC). The quantitative study of the variations of the sample mass loss and of the mass of ILC reveals the existence of a transient period followed by a steady-state regime resulting from an equilibrium between cellulose decomposition into ILC and ILC vaporization. A mathematical model has been solved in parallel. The results agree very well with the experimental measurements and yield additional information on the temperatures of cellulose pyrolysis and of ILC vaporization.

Zeshao Chen - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic and optical analysis for a cpv t hybrid system with beam splitter and fully tracked linear fresnel reflector concentrator utilizing sloped panels
    Solar Energy, 2014
    Co-Authors: Peng Hu, Qian Bo-zhang, Zeshao Chen
    Abstract:

    Abstract Spectral splitting technology that separates solar spectrum into several parts and enables different energy conversions such as photovoltaic (PV) conversion and photo-thermal conversion aims to utilize the full spectrum solar energy efficiently. A novel concentrating PV/Thermal (CPV/T) hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels was proposed in this study. The relations between the structural parameters and the optical performances of the system were investigated. The Concentrated Radiation distribution on the PV device surface was simulated by taking into account the main optical errors and shows a good uniformity. Based on the experimental data of the components, thermodynamic analysis on the CPV/T hybrid system was carried out and the results reveal that the overall energy conversion efficiencies of the proposed CPV/T hybrid system is higher than that of the CPV system under the same conditions.

  • Thermodynamic and optical analysis for a CPV/T hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels
    Solar Energy, 2014
    Co-Authors: Peng Hu, Qian Bo-zhang, Zeshao Chen
    Abstract:

    Abstract Spectral splitting technology that separates solar spectrum into several parts and enables different energy conversions such as photovoltaic (PV) conversion and photo-thermal conversion aims to utilize the full spectrum solar energy efficiently. A novel concentrating PV/Thermal (CPV/T) hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels was proposed in this study. The relations between the structural parameters and the optical performances of the system were investigated. The Concentrated Radiation distribution on the PV device surface was simulated by taking into account the main optical errors and shows a good uniformity. Based on the experimental data of the components, thermodynamic analysis on the CPV/T hybrid system was carried out and the results reveal that the overall energy conversion efficiencies of the proposed CPV/T hybrid system is higher than that of the CPV system under the same conditions.

Peng Hu - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic and optical analysis for a cpv t hybrid system with beam splitter and fully tracked linear fresnel reflector concentrator utilizing sloped panels
    Solar Energy, 2014
    Co-Authors: Peng Hu, Qian Bo-zhang, Zeshao Chen
    Abstract:

    Abstract Spectral splitting technology that separates solar spectrum into several parts and enables different energy conversions such as photovoltaic (PV) conversion and photo-thermal conversion aims to utilize the full spectrum solar energy efficiently. A novel concentrating PV/Thermal (CPV/T) hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels was proposed in this study. The relations between the structural parameters and the optical performances of the system were investigated. The Concentrated Radiation distribution on the PV device surface was simulated by taking into account the main optical errors and shows a good uniformity. Based on the experimental data of the components, thermodynamic analysis on the CPV/T hybrid system was carried out and the results reveal that the overall energy conversion efficiencies of the proposed CPV/T hybrid system is higher than that of the CPV system under the same conditions.

  • Thermodynamic and optical analysis for a CPV/T hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels
    Solar Energy, 2014
    Co-Authors: Peng Hu, Qian Bo-zhang, Zeshao Chen
    Abstract:

    Abstract Spectral splitting technology that separates solar spectrum into several parts and enables different energy conversions such as photovoltaic (PV) conversion and photo-thermal conversion aims to utilize the full spectrum solar energy efficiently. A novel concentrating PV/Thermal (CPV/T) hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels was proposed in this study. The relations between the structural parameters and the optical performances of the system were investigated. The Concentrated Radiation distribution on the PV device surface was simulated by taking into account the main optical errors and shows a good uniformity. Based on the experimental data of the components, thermodynamic analysis on the CPV/T hybrid system was carried out and the results reveal that the overall energy conversion efficiencies of the proposed CPV/T hybrid system is higher than that of the CPV system under the same conditions.

Qian Bo-zhang - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic and optical analysis for a cpv t hybrid system with beam splitter and fully tracked linear fresnel reflector concentrator utilizing sloped panels
    Solar Energy, 2014
    Co-Authors: Peng Hu, Qian Bo-zhang, Zeshao Chen
    Abstract:

    Abstract Spectral splitting technology that separates solar spectrum into several parts and enables different energy conversions such as photovoltaic (PV) conversion and photo-thermal conversion aims to utilize the full spectrum solar energy efficiently. A novel concentrating PV/Thermal (CPV/T) hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels was proposed in this study. The relations between the structural parameters and the optical performances of the system were investigated. The Concentrated Radiation distribution on the PV device surface was simulated by taking into account the main optical errors and shows a good uniformity. Based on the experimental data of the components, thermodynamic analysis on the CPV/T hybrid system was carried out and the results reveal that the overall energy conversion efficiencies of the proposed CPV/T hybrid system is higher than that of the CPV system under the same conditions.

  • Thermodynamic and optical analysis for a CPV/T hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels
    Solar Energy, 2014
    Co-Authors: Peng Hu, Qian Bo-zhang, Zeshao Chen
    Abstract:

    Abstract Spectral splitting technology that separates solar spectrum into several parts and enables different energy conversions such as photovoltaic (PV) conversion and photo-thermal conversion aims to utilize the full spectrum solar energy efficiently. A novel concentrating PV/Thermal (CPV/T) hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels was proposed in this study. The relations between the structural parameters and the optical performances of the system were investigated. The Concentrated Radiation distribution on the PV device surface was simulated by taking into account the main optical errors and shows a good uniformity. Based on the experimental data of the components, thermodynamic analysis on the CPV/T hybrid system was carried out and the results reveal that the overall energy conversion efficiencies of the proposed CPV/T hybrid system is higher than that of the CPV system under the same conditions.

Hulin Huang - One of the best experts on this subject based on the ideXlab platform.

  • design and thermal performances of semi parabolic linear fresnel reflector solar concentration collector
    Energy Conversion and Management, 2014
    Co-Authors: Hulin Huang
    Abstract:

    A Semi-Parabolic Linear Fresnel Reflector (SPLFR) solar concentrator is proposed in this paper. The SPLFR is formed by linear plate mirrors whose edges located at a parabolic line. The ray trace simulation results show the SPLFR has the same concentrating efficiency as that of the parabolic trough concentrator (PTC), but lower manufacture cost. The SPLFR concentrator has higher ground utilization ratio compared with that of Linear Fresnel Reflector (LFR) concentrator because it has no shading and blocking shortcomings. The SPLFR Concentrated Radiation distribution along the circumference of absorber pipe cross section is investigated and compared with that of LFR concentrator. The thermal performance of linear evacuated absorber for the SPLFR is simulated numerically as well. The nonuniform Radiation distribution induces two convection eddies at each side of absorber pipe which enhances the heat transfer from the wall of absorber to the working fluid.