TY - JOUR
T1 - Drying recycled fiber rejects in a bench-scale cyclone
T2 - Influence of device geometry and operational parameters on drying mechanisms
AU - Grimm, A.
AU - Elustondo, D.
AU - Mäkelä, Mikko
AU - Segerström, M.
AU - Kalén, G.
AU - Fraikin, L.
AU - Léonard, A.
AU - Larsson, S.H.
N1 - Funding Information:
This work was financed by The Swedish Research Council (FORMAS) under project number 213-2014-182. We thank Bio4Energy, a strategic research environment appointed by the Swedish government, for supporting this work.
Publisher Copyright:
© 2017 Elsevier B.V.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017
Y1 - 2017
N2 - Significant amounts of waste sludge and rejects are generated by pulp and paper mills, and stricter environmental regulations have made waste handling a global challenge. Thermochemical conversion of mechanically dewatered by-products is expensive and inefficient due to their high moisture content; therefore drying is a vital unit operation in waste management. This paper reports results from drying of light coarse fiber reject in a bench-scale cyclone that allows changes in geometry. For the sake of comparison, convective fixed-bed drying tests were also performed. The results showed that the drying rate in the cyclone was hundreds of times higher than in the fixed-bed. For cyclone drying, the inlet air velocity was the most important factor in both determining the drying rate and residence time of the material. This led to the hypothesis that grinding of the reject particles due to particle-wall and particle-particle collisions play a crucial role in enhancing the efficiency of heat and mass transfer. In addition to inlet air velocity, cyclone geometry was the main factor that determined particle residence time, as drying air temperature mainly determined drying rate.
AB - Significant amounts of waste sludge and rejects are generated by pulp and paper mills, and stricter environmental regulations have made waste handling a global challenge. Thermochemical conversion of mechanically dewatered by-products is expensive and inefficient due to their high moisture content; therefore drying is a vital unit operation in waste management. This paper reports results from drying of light coarse fiber reject in a bench-scale cyclone that allows changes in geometry. For the sake of comparison, convective fixed-bed drying tests were also performed. The results showed that the drying rate in the cyclone was hundreds of times higher than in the fixed-bed. For cyclone drying, the inlet air velocity was the most important factor in both determining the drying rate and residence time of the material. This led to the hypothesis that grinding of the reject particles due to particle-wall and particle-particle collisions play a crucial role in enhancing the efficiency of heat and mass transfer. In addition to inlet air velocity, cyclone geometry was the main factor that determined particle residence time, as drying air temperature mainly determined drying rate.
UR - http://www.scopus.com/inward/record.url?scp=85027333505&partnerID=8YFLogxK
U2 - 10.1016/j.fuproc.2017.08.004
DO - 10.1016/j.fuproc.2017.08.004
M3 - Article
SN - 0378-3820
VL - 167
SP - 631
EP - 640
JO - Fuel Processing Technology
JF - Fuel Processing Technology
ER -