Experimental study of pyrolysis and steam gasification of sewage sludge in fluidized bed reactors between 700 and 900 deg. C: comparison with woody wastes
Description
The gasification of lignocellulosic biomass is viewed as a promising technological solution for the production of a high value-added gas that could be used in several applications. However, emerging tensions in the wood market are prompting industrial actors to turn to other lignocellulosic resources, such as agricultural residues, municipal green waste and sewage sludge (SS). Depending on the case, these wastes are considered as effluents with a zero or negative cost. The objective of this work is to better understand and model the phenomena that occur during the gasification of sewage sludge and green wastes in a fluidized bed. Firstly, a physicochemical and textural characterization study of the selected fuels and their chars resulting from their rapid pyrolysis as well as a kinetic study on the influence of the pyrolysis temperature and the nature of solid fuel on the reactivity of char were presented. Then, the results obtained during the pyrolysis and steam gasification of wastes, in a fluidized bed gasification pilot plant, are presented for temperatures ranging between 700 and 900 deg. C. Parametric studies allows to better understand the effect of operating parameters (temperature, H2O/fuel mass ratio, the nature of the fuel and the kind of the fluidized medium) on the gasification performance and to identify the key parameters that control the composition, as well as the syngas production yield. Moreover, reaction schemes are proposed based on the experimental results, for the pyrolysis of wastes between 700 and 900 deg. C. Finally, the results of a modelling study of the gasifier, integrating the reactions of pyrolysis, char steam gasification, water-gas shift and tar reforming are presented and compared to the experimental results in order to better understand the effect of the operating parameters on the conversion rate of different reactions. (author)
Abstract (French)
La gazeification des biomasses lignocellulosiques apparait actuellement comme une solution technologique prometteuse permettant la production d'un gaz a haute valeur ajoutee, utilisable dans de nombreuses applications. Cependant, les tensions qui commencent a apparaitre sur le marche du bois incitent les acteurs du secteur a se tourner vers d'autres ressources lignocellulosiques telles que les residus agricoles, les dechets verts municipaux et les boues de STEP. Suivant les cas, ces dechets sont vus comme des effluents a traiter dont le cout peut etre parfois nul ou negatif. L'objectif de ces travaux est de mieux comprendre et modeliser les phenomenes qui se deroulent lors de la gazeification des dechets (boues de STEP et dechets verts municipaux) en lit fluidise. Dans un premier temps, sont presentes successivement une etude de caracterisation physico chimique et texturale des intrants utilises ainsi que des chars issus de leur pyrolyse rapide ainsi qu'une etude cinetique portant sur l'influence de la temperature de pyrolyse et de la nature de l'intrant sur la reactivite de char. Dans un second temps, sont exposes les resultats obtenus lors de la pyrolyse et de la vapogazeification des dechets dans un pilote de pyrogazeification en lit fluidise entre 700 et 900 deg. C. Les etudes parametriques ont permis de mettre en evidence l'effet des parametre operatoires (temperature, rapport massique H2O/intrant, nature de l'intrant et du media fluidise) sur les performances de la gazeification et d'identifier les parametres cles permettant de controler la composition ainsi que le taux de production du gaz de synthese. Par ailleurs, a partir des resultats obtenus sont proposes des schemas reactionnels pour la pyrolyse des dechets entre 700 et 900 deg. C. Enfin, les resultats d'une etude de modelisation du reacteur de gazeification des dechets en lit fluidise integrant les reactions de pyrolyse, de vapogazeification du char, de water-gas shift et de reformage des goudrons sont presentes et compares avec les resultats experimentaux afin de mieux comprendre l'effet des parametres operatoires sur les taux d'avancement de differentes reactions. (auteur)
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Additional details
Additional titles
- Original title (French)
- Etude experimentale de pyrolyse et de vapogazeification des boues de STEP en reacteurs a lit fluidise entre 700 et 900 deg. C: comparaison avec les dechets boises
Publishing Information
- Imprint Pagination
- 263 p.
- Report number
- FRNC-TH--13145
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 53079789
- Subject category
- S09: BIOMASS FUELS;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- CATALYTIC REFORMING; CHARCOAL; CHEMICAL REACTION KINETICS; FLUIDIZED BED REFUSE GASIFICATION; FLUIDIZED BEDS; PARAMETRIC ANALYSIS; PILOT PLANTS; PYROLYSIS; PYROLYSIS PRODUCTS; SEWAGE SLUDGE; SYNGAS PROCESS; SYNTHESIS GAS; TEMPERATURE DEPENDENCE; THERMODYNAMIC PROPERTIES; WATER GAS PROCESSES; WOOD WASTES
- Descriptors DEC
- ADSORBENTS; BIOLOGICAL MATERIALS; BIOLOGICAL WASTES; CHEMICAL REACTIONS; DECOMPOSITION; FLUIDS; FUNCTIONAL MODELS; GASES; GASIFICATION; KINETICS; MANAGEMENT; MATERIALS; ORGANIC WASTES; PHYSICAL PROPERTIES; PROCESSING; REACTION KINETICS; REFORMER PROCESSES; SEWAGE; SLUDGES; SOLID WASTES; THERMOCHEMICAL PROCESSES; WASTE MANAGEMENT; WASTE PROCESSING; WASTES
Optional Information
- Notes
- 135 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses