Measurement and theoretical prediction of char temperature oscillation during fluidized bed combustion
Artikel i vetenskaplig tidskrift, 2018

There is experimental evidence of oscillations of the char particle temperature during combustion in a fluidized bed (FB), resulting from the movement of the char throughout the bed. However, in most theoretical FB combustion studies the char particle is assumed to always stay in the emulsion phase, and existing models do not take into account the movement of the char particle explicitly. Moreover, it is difficult to quantify the magnitude and frequency of these temperature oscillations with the common measurement techniques employed in FB (thermocouple and pyrometry with optical probe). In this work, the combustion of single char particles (8 mm) from beech wood and sub-bituminous coal is carried out in a 2-dimensional FB made of quartz, using two O2 concentrations (11 and 21%v) in N2. The time-evolution of the temperature and the size of the char in the different phases are estimated by the analysis of images resulting from a new method combining pyrometry with readings from a digital camera. It is found that the combustion temperature oscillates in hundredths of seconds with an amplitude varying from 10 to 100 °C, resulting from the movement of a particle between the emulsion, bubble and splash phases. The amplitude increases with higher O2 concentration and smaller char-particle size. A combustion model is developed using the experimental characterization of the movement of the char particle through the bed as input. The temperature and burnout time predicted by the model compare well (within 15 %) with measurements obtained from this work and from literature.

Biomass Char temperature Coal Combustion Fluidized bed Pyrometry

Författare

Jesús Salinero

Universidad de Sevilla

Alberto Gomez Barea

Universidad de Sevilla

Diego Fuentes-Cano

Universidad de Sevilla

Bo G Leckner

Chalmers, Rymd-, geo- och miljövetenskap, Energiteknik

Combustion and Flame

0010-2180 (ISSN)

Vol. 192 190-204

Drivkrafter

Hållbar utveckling

Ämneskategorier

Energiteknik

Kemiska processer

Styrkeområden

Energi

Infrastruktur

Chalmers kraftcentral

DOI

10.1016/j.combustflame.2018.02.005

Mer information

Senast uppdaterat

2018-09-06