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Title: Modeling residence-time distribution in horizontal screw hydrolysis reactors

Abstract

The dilute-acid thermochemical hydrolysis step used in the production of liquid fuels from lignocellulosic biomass requires precise residence-time control to achieve high monomeric sugar yields. Difficulty has been encountered reproducing residence times and yields when small batch reaction conditions are scaled up to larger pilot-scale horizontal auger-tube type continuous reactors. A commonly used naive model estimated residence times of 6.2-16.7 min, but measured mean times were actually 1.4-2.2 the estimates. Here, this study investigated how reactor residence-time distribution (RTD) is affected by reactor characteristics and operational conditions, and developed a method to accurately predict the RTD based on key parameters. Screw speed, reactor physical dimensions, throughput rate, and process material density were identified as major factors affecting both the mean and standard deviation of RTDs. The general shape of RTDs was consistent with a constant value determined for skewness. The Peclet number quantified reactor plug-flow performance, which ranged between 20 and 357.

Authors:
 [1];  [1]
  1. 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 (EE-3B)
OSTI Identifier:
1407460
Report Number(s):
NREL/JA-5100-68272
Journal ID: ISSN 0009-2509
Grant/Contract Number:
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemical Engineering Science
Additional Journal Information:
Journal Volume: 175; Journal Issue: C; Journal ID: ISSN 0009-2509
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; residence-time distribution; screw-conveyed reaction; biomass pretreatment; transport modeling; biomass bulk density

Citation Formats

Sievers, David A., and Stickel, Jonathan J. Modeling residence-time distribution in horizontal screw hydrolysis reactors. United States: N. p., 2017. Web. doi:10.1016/j.ces.2017.10.012.
Sievers, David A., & Stickel, Jonathan J. Modeling residence-time distribution in horizontal screw hydrolysis reactors. United States. doi:10.1016/j.ces.2017.10.012.
Sievers, David A., and Stickel, Jonathan J. Thu . "Modeling residence-time distribution in horizontal screw hydrolysis reactors". United States. doi:10.1016/j.ces.2017.10.012.
@article{osti_1407460,
title = {Modeling residence-time distribution in horizontal screw hydrolysis reactors},
author = {Sievers, David A. and Stickel, Jonathan J.},
abstractNote = {The dilute-acid thermochemical hydrolysis step used in the production of liquid fuels from lignocellulosic biomass requires precise residence-time control to achieve high monomeric sugar yields. Difficulty has been encountered reproducing residence times and yields when small batch reaction conditions are scaled up to larger pilot-scale horizontal auger-tube type continuous reactors. A commonly used naive model estimated residence times of 6.2-16.7 min, but measured mean times were actually 1.4-2.2 the estimates. Here, this study investigated how reactor residence-time distribution (RTD) is affected by reactor characteristics and operational conditions, and developed a method to accurately predict the RTD based on key parameters. Screw speed, reactor physical dimensions, throughput rate, and process material density were identified as major factors affecting both the mean and standard deviation of RTDs. The general shape of RTDs was consistent with a constant value determined for skewness. The Peclet number quantified reactor plug-flow performance, which ranged between 20 and 357.},
doi = {10.1016/j.ces.2017.10.012},
journal = {Chemical Engineering Science},
number = C,
volume = 175,
place = {United States},
year = {Thu Oct 12 00:00:00 EDT 2017},
month = {Thu Oct 12 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on October 12, 2018
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