Formulation and validation of a computational model for a dilute biomass slurry undergoing rotational mixing
Abstract
In this paper we develop a computational model for the mixing and transport of a dilute biomass slurry. The objective was to create a sufficiently simple and efficient model for biomass transport that can be coupled with reaction models for the study of conversion of cellulosic biomass into fermentable sugars. Our target system is 5%bymass ..alpha..cellulose, which is our proxy for more complex lignocellulosic biomass. In the authors' previous work, an experimental investigation with ..alpha..cellulose under two vanemixer configurations showed a bifurcation between a settling regime, for which settling effects dominate, and a suspended regime, for which solids are mostly suspended. Here, a mixedfluid model was chosen, for which the model for the mixturevelocity field is the incompressible NavierStokes equations under the Boussinesq approximation for buoyancy. Solids transport includes solids motion due to diffusion, settling, advection, and shear. Comparison of simulated and experimental results show good agreement in the suspended regime, and in capturing the bifurcation rate. While the model captured well the distribution of solids in the settling regime, the model was incapable of capturing the high torque values seen in experiments with vanishing mixer rotation rate.
 Authors:

 National Renewable Energy Lab. (NREL), Golden, CO (United States)
 Publication Date:
 Research Org.:
 National Renewable Energy Lab. (NREL), Golden, CO (United States)
 Sponsoring Org.:
 USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE3B)
 OSTI Identifier:
 1427349
 Alternate Identifier(s):
 OSTI ID: 1548687
 Report Number(s):
 NREL/JA500070621
Journal ID: ISSN 00092509; TRN: US1802584
 Grant/Contract Number:
 AC3608GO28308; AC3608GO28308
 Resource Type:
 Accepted Manuscript
 Journal Name:
 Chemical Engineering Science
 Additional Journal Information:
 Journal Volume: 182; Journal Issue: C; Journal ID: ISSN 00092509
 Publisher:
 Elsevier
 Country of Publication:
 United States
 Language:
 English
 Subject:
 09 BIOMASS FUELS; multiphase flow; sedimentation; spectral finite elements; highorder methods
Citation Formats
Sprague, Michael A., Stickel, Jonathan J., Sitaraman, Hariswaran, and Crawford, Nathan. Formulation and validation of a computational model for a dilute biomass slurry undergoing rotational mixing. United States: N. p., 2018.
Web. doi:10.1016/j.ces.2018.02.030.
Sprague, Michael A., Stickel, Jonathan J., Sitaraman, Hariswaran, & Crawford, Nathan. Formulation and validation of a computational model for a dilute biomass slurry undergoing rotational mixing. United States. doi:10.1016/j.ces.2018.02.030.
Sprague, Michael A., Stickel, Jonathan J., Sitaraman, Hariswaran, and Crawford, Nathan. Sat .
"Formulation and validation of a computational model for a dilute biomass slurry undergoing rotational mixing". United States. doi:10.1016/j.ces.2018.02.030. https://www.osti.gov/servlets/purl/1427349.
@article{osti_1427349,
title = {Formulation and validation of a computational model for a dilute biomass slurry undergoing rotational mixing},
author = {Sprague, Michael A. and Stickel, Jonathan J. and Sitaraman, Hariswaran and Crawford, Nathan},
abstractNote = {In this paper we develop a computational model for the mixing and transport of a dilute biomass slurry. The objective was to create a sufficiently simple and efficient model for biomass transport that can be coupled with reaction models for the study of conversion of cellulosic biomass into fermentable sugars. Our target system is 5%bymass ..alpha..cellulose, which is our proxy for more complex lignocellulosic biomass. In the authors' previous work, an experimental investigation with ..alpha..cellulose under two vanemixer configurations showed a bifurcation between a settling regime, for which settling effects dominate, and a suspended regime, for which solids are mostly suspended. Here, a mixedfluid model was chosen, for which the model for the mixturevelocity field is the incompressible NavierStokes equations under the Boussinesq approximation for buoyancy. Solids transport includes solids motion due to diffusion, settling, advection, and shear. Comparison of simulated and experimental results show good agreement in the suspended regime, and in capturing the bifurcation rate. While the model captured well the distribution of solids in the settling regime, the model was incapable of capturing the high torque values seen in experiments with vanishing mixer rotation rate.},
doi = {10.1016/j.ces.2018.02.030},
journal = {Chemical Engineering Science},
number = C,
volume = 182,
place = {United States},
year = {2018},
month = {2}
}
Web of Science
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