Masters Theses
Date of Award
5-2018
Degree Type
Thesis
Degree Name
Master of Science
Major
Biosystems Engineering
Major Professor
Nicole Labbe, Nourredine H. Abdoulmoumine
Committee Members
Xiaofei Ye
Abstract
Recovery of the wood preservative copper naphthenate (CN) from end-of-life railroad ties was investigated to promote the secondary use of this biomass as a fuel source and mitigate the negative impacts of landfilling and other alternative tie disposal methods. Thermal desorption of naphthenic acids from CN-treated ties preceded inorganic extraction with ethylenediaminetetraacetic acid (EDTA) and biodegradable chelating agents, 2,6-pyridine dicarboxylic acid (PDA) and 1-hydroxy ethylidene-1,1-disphosphonic acid (HEDP). Organic preservative components were recovered from thermal pretreatment at temperatures between 225 and 300 °C. This thermal desorption also mirrored torrefaction by increasing the ties’ higher heating value and carbon content, in addition to lowering the moisture content within the biomass. These effects improved the biomass properties for use as a thermochemical conversion feedstock. Preservative component recovery was assessed at micro-, bench-, and pilot-scales, demonstrating scalability of the proposed process. Extraction efficiency of copper and other naturally present inorganics with PDA after thermal desorption was the most effective of those tested, further upgrading the properties of the biomass for pyrolysis. The ash content of the biomass was decreased by up to 64 % using PDA, and 100 % of copper was removed from both the raw sample and that desorbed at 225 °C specifically. Estimations of the bio-oil yields that would be generated from subsequent fast pyrolysis of the ties were completed based on a review of literature. The sample that has undergone both pretreatment steps is expected to generate the highest quantity of bio-oil from subsequent fast pyrolysis, as well as the highest quality.
Recommended Citation
Haber, Holly Lauren, "Sustainable Method for Recovery of Copper Naphthenate from Used Railroad Ties. " Master's Thesis, University of Tennessee, 2018.
https://trace.tennessee.edu/utk_gradthes/5033
Comments
A version of Chapter II of this thesis was originally published by Holly L. Haber, Pyoungchung Kim, Stephen C. Chmely, Jeff Lloyd, Yagya N. Regmi, Nourredine Abdoulmoumine and Nicole Labbé. I has been reprinted with permission from “Environmentally Friendly Process for Recovery of Wood Preservative from Used Copper-Naphthenate Treated Railroad Ties” in American Chemical Society’s Sustainable Chemistry and Engineering, 2017, DOI: 10.1021/acssuschemeng.7b02760. Copyright 2017 American Chemical Society.