A NOVEL FAST PYROLYSIS MODEL BASED ON VARIABLE-POWER IMAGE FURNACE RESULTS

Guillain Mauviel (1) , Melina Christodolou (1) , Jacques Lédé (1) , Francis Billaud (1)

1 GREENER

Nowadays, ligno-cellulosic biomass is considered as a renewable carbon resource. It represents a relevant alternative to reduce greenhouse gases emissions. During last decades, many scientists and industrials have been interested in thermochemical conversion of biomass such as gasification. In order to accurately model the gasifiers, it is important to study the implied thermochemical phenomena (such as pyrolysis), through dedicated experiments close to the industrial conditions. This communication presents the model developed by LRGP to describe primary pyrolysis in bubbling fluidized beds conditions, one of the major technologies used for biomass gasification. The novelties of this proposed model are the coarse description of the 3 main products (gas, vapours, char) and the conservation of the 3 main biomass elements: carbon, hydrogen, oxygen. The work is part of the Gaya project, led by GDF Suez and funded by ADEME. Gaya project will contribute to develop a new gasification demonstration platform in Europe for SNG production. The experimental setup used to adjust the pyrolysis model is a vertical image furnace [Christodoulou & al 2012]. The principle is to concentrate the radiation of a xenon arc lamp on a biomass sample. The lamp is settled at the first focus of an elliptical mirror. The light beams are concentrated at the second focus where the biomass sample is placed inside a transparent reactor. In order to prevent any gas-phase secondary reactions, the volatile matter (vapours and gases) released during the reaction is quenched by a controlled flow of nitrogen at room temperature. During a flash time, the temperature evolution is measured by pyrometry on both sides. As soon as the light beams are switched off, all the pyrolysis products can be recovered, allowing achieving complete mass balances. Gases are collected in a sampling bag, liquids are condensed and aerosols are trapped in a filter. The solid residue remains on the sample holder in the reactor. All these products are analysed off-line. The heat flux density applied to the biomass can reach 650 kW m -2 . This is the maximum value encountered by wood particles surrounded by hot bed particles in fluidized bed gasifier. The heat flux density is decreased over time in order to reproduce the thermal story of a wood particle injected inside a fluidized bed.

Domaines: Génie des procédés

Guillain Mauviel, Melina Christodolou, Jacques Lédé, Francis Billaud. A NOVEL FAST PYROLYSIS MODEL BASED ON VARIABLE-POWER IMAGE FURNACE RESULTS. AIChE 2013 Annual meeting, Nov 2013, San Francisco, United States. ⟨hal-01089243⟩