Riccardo Chirone

Gas fluidization is one of the best available techniques to disperse and process large quantities of nanosized powders. Nevertheless, on the basis of their primary particle size and material density, fine powders fall under the Geldart group C (<30 μm) classification, which means that fluidization is expected to be particularly difficult because of cohesive forces existing between particles. In order to overcome these inter-particle forces and achieve a smooth fluidization regime, externally assisted fluidization can be used, thus involving the application of additional forces. Among all the available techniques, sound assisted fluidization has been indicated as one of the best technological option. The present work is focused on the study of the fluidization and mixing of nanoparticles under sound assisted conditions. All the fluidization tests have been performed at ambient temperature and pressure in a laboratory scale sound assisted apparatus. In particular, the first section...

The interest in fluidized bed combustion/gasification of low rank coal emphasizes the importance of a better understanding of the “in-situ” devolatilization kinetics. Despite the widespread literature on this subject, there is still a vigorous debate on the mechanisms controlling the release of volatile matter under fluidized bed processing conditions and on its relevance to the reactor performance.

Abstract Self-segregation of fuel particles during devolatilization in fluidized bed combustors (FBCs) is detrimental to efficient and trouble-free operation. It may be effectively contrasted by promoting vigorous circulation of fluidized solids. As an example,“Gulf Stream” may be induced by controlled uneven distribution of fluidizing gas flow through the distributor. The present study is aimed at characterizing bed hydrodynamics in a pilot scale fluidized bed combustor revamped to optimize combustion of high-volatile solid fuels. The FBC ...

ABSTRACT A preliminary study on oxygen - steam gasification of wood and olive husk/coal pellets was carried out in a pre-pilot scale bubbling fluidized bed reactor. Two different bed materials were adopted: inert quartzite and Ni-alumina catalyst. The influence of the equivalence ratio (ER), steam oxygen ratio (SOR) and bed temperature on the concentration of stable gas (e.g. H2, CO2, CO and CH4) as well as on the efficiency of tar conversion and syngas heating value were studied. the oxygen enrichment of gasification atmosphere, in respect to air-steam gasification leads to highest char carbon conversion and, of course, limited dilution in nitrogen of the syngas. In contrast, the tar content is still somewhat high, even simpler tar species were detected, and a higher CO2 level is attained in the syngas.

... P. Ammendola and R. Chirone Istituto di Ricerche sulla Combustione – CNR P. le Tecchio 80, 80125 Napoli, Italy T: +39-0817682245; F: +39-0815936936; E: paola.ammendola@irc.cnr.it ABSTRACT ... 1. Zhu C., Yu Q., Dave RN, Pfeffer R., AIChE Journal, 51, 426, 2005. ...