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Title: Biomass drying in a pulsed fluidized bed without inert bed particles

Abstract

Batch drying was performed in the pulsed fluidized bed with various species of biomass particles as an indicator of gas–solid contact efficiency and mass transfer rate under different operating conditions including pulsation duty cycle and particle size distribution. The fluidization of cohesive biomass particles benefited from the shorter opening time of pulsed gas flow and increased peak pressure drop. The presence of fines enhanced gas–solid contact of large and irregular biomass particles, as well as the mass transfer efficiency. A drying model based on two-phase theory was proposed, from which effective diffusivity was calculated for various gas flow rates, temperature and pulsation frequency. Intricate relationship was discovered between pulsation frequency and effective diffusivity, as mass transfer was deeply connected with the hydrodynamics. Effective diffusivity was also found to be proportional to gas flow rate and drying temperature. In conclusion, operating near the natural frequency of the system also favored drying and mass transfer.

Authors:
 [1];  [1];  [1];  [2];  [3]
  1. The Univ. of British Columbia, Vancouver, BC (Canada)
  2. The Univ. of British Columbia, Vancouver, BC (Canada); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. The Univ. of Tokyo, Tokyo (Japan)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1328340
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Fuel
Additional Journal Information:
Journal Volume: 186; Journal Issue: C; Journal ID: ISSN 0016-2361
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; fluidized bed; pulsation; modeling; drying; mass transfer; biomass

Citation Formats

Jia, Dening, Bi, Xiaotao, Lim, C. Jim, Sokhansanj, Shahab, and Tsutsumi, Atsushi. Biomass drying in a pulsed fluidized bed without inert bed particles. United States: N. p., 2016. Web. doi:10.1016/j.fuel.2016.08.100.
Jia, Dening, Bi, Xiaotao, Lim, C. Jim, Sokhansanj, Shahab, & Tsutsumi, Atsushi. Biomass drying in a pulsed fluidized bed without inert bed particles. United States. doi:10.1016/j.fuel.2016.08.100.
Jia, Dening, Bi, Xiaotao, Lim, C. Jim, Sokhansanj, Shahab, and Tsutsumi, Atsushi. 2016. "Biomass drying in a pulsed fluidized bed without inert bed particles". United States. doi:10.1016/j.fuel.2016.08.100. https://www.osti.gov/servlets/purl/1328340.
@article{osti_1328340,
title = {Biomass drying in a pulsed fluidized bed without inert bed particles},
author = {Jia, Dening and Bi, Xiaotao and Lim, C. Jim and Sokhansanj, Shahab and Tsutsumi, Atsushi},
abstractNote = {Batch drying was performed in the pulsed fluidized bed with various species of biomass particles as an indicator of gas–solid contact efficiency and mass transfer rate under different operating conditions including pulsation duty cycle and particle size distribution. The fluidization of cohesive biomass particles benefited from the shorter opening time of pulsed gas flow and increased peak pressure drop. The presence of fines enhanced gas–solid contact of large and irregular biomass particles, as well as the mass transfer efficiency. A drying model based on two-phase theory was proposed, from which effective diffusivity was calculated for various gas flow rates, temperature and pulsation frequency. Intricate relationship was discovered between pulsation frequency and effective diffusivity, as mass transfer was deeply connected with the hydrodynamics. Effective diffusivity was also found to be proportional to gas flow rate and drying temperature. In conclusion, operating near the natural frequency of the system also favored drying and mass transfer.},
doi = {10.1016/j.fuel.2016.08.100},
journal = {Fuel},
number = C,
volume = 186,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 1work
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  • Fluidization of biomass particles in the absence of inert bed materials has been tested in a pulsed fluidized bed with vibration, with the pulsation frequency ranging from 033 to 6.67 Hz. Intermittent fluidization at 033 Hz and apparently 'normal' fluidization at 6.67 Hz with regular bubble patterns were observed. Pulsation has proven to be effective in overcoming the bridging of irregular biomass particles induced by strong inter-particle forces. The vibration is only effective when the pulsation is inadequate, either at too low a frequency or too low in amplitude. We dried biomass in order to quantify the effectiveness of gasmore » pulsation for fluidized bed dryers and torrefiers in terms of gas-solid contact efficiency and heat and mass transfer rates. Furthermore, the effects of gas flow rate, bed temperature, pulsation frequency and vibration intensity on drying performance have been systematically investigated. While higher temperature and gas flow rate are favored in drying, there exists an optimal range of pulsation frequency between 0.75 Hz and 1.5 Hz where gas-solid contact is enhanced in both the constant rate drying and falling rate drying periods.« less
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