In this section, you can access to the latest technical information related to the RECYPACK project topic.

Heat transfer in packed-beds of agricultural waste with low rates of air flow applicable to solid-state fermentation

Heat transfer studies were carried out in packed-beds (PBs) heated by the wall and percolated by low air flow rates. Porous media were composed by particles of sugarcane bagasse (SCB) and by a mixture of particles of SCB, orange pulp and peel (OPP) and wheat bran (WB) at proportion SCB:OPP:WB 1:2:2 w/w (composed medium), agricultural waste used as substrates in bioreactors of solid-state fermentation (SSF), an interesting biotechnological application of PBs. Once metabolic heat generated has to be dissipated, heat transfer studies and thermal parameters are required. Tube-to-particle diameter ratio was D/dp?=?260, bed height ranged from L?=?60 to 180?mm, while air flow rate ranged from 400 to 1200?L/h. Air temperature was 40?°C and wall temperature 65?°C. The outlet bed temperatures (TL) were measured by ring-shaped sensors and by aligned thermocouples. Average temperatures (Tavg) and global heat transfer coefficients (U) were calculated separately for central region of the beds and for wall-vicinity. Radial effective thermal conductivity (?r) and wall-to-fluid convective heat transfer coefficient (?wall) have been estimated by means of the traditional two-parameters model. Radial temperature profiles at bed outlet were flattened in the central region and convergent at the edge of the packs. The two-regions approximation for U calculations showed to be appropriate for both packs. Global coefficient U, thermal conductivity ?r and convective coefficient ?wall increased with increasing air flow rate and decreased with bed height. ?r tended to the stagnant value of the thermal conductivity and ?wall were lower than 50?W/m2/°C, addressing the difficulty on removing metabolic heat from PBs of SSF.

» Author: Fernanda Perpétua Casciatori, João Cláudio Thoméo

» Reference: Chemical Engineering Science, Volume 188

» Publication Date: 12/10/2018

» More Information

« Go to Technological Watch

The development of this project has been co-funded with the support of the LIFE financial instrument of the European Union
[LIFE16 ENV/ES/000305]

This publication reflects only the author's view and that the Agency/Commission is not responsible for any use that may be made of the information it contains



AIMPLAS Instituto Tecnológico del Plástico

(+34) 96 136 60 40 (Ext. 128)