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Title: Influence of process conditions and interventions on metals content in biocrude from hydrothermal liquefaction of microalgae

Abstract

We determined how different reaction conditions influence the metals contents in biocrude oil and other product fractions from hydrothermal liquefaction (HTL) of microalgae. We then assessed the effect of using different solvents for biocrude recovery and adding catalysts on the metal content in the biocrude. The Fe content was lower and the Na content higher in biocrude produced at higher temperature (400 vs 350 °C) and longer holding time (60 vs 3 min). The Fe and Na contents were reduced over 50% and 95%, respectively, by use of methyl tert-butyl ether (MTBE ) rather than dichloromethane as the organic solvent for biocrude recovery and they were reduced over 98% via additional application of a supported Ni catalyst during HTL. Finally, this work demonstrates that the hydrothermal treatment conditions influence the metal content in biocrude and that judicious selection of solvent and catalyst can lead to significant reduction in the metal content in biocrude.

Authors:
 [1];  [1]
  1. Pennsylvania State Univ., University Park, PA (United States). Dept of Chemical Engineering
Publication Date:
Research Org.:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B)
OSTI Identifier:
1415271
Grant/Contract Number:
EE0006315
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Algal Research
Additional Journal Information:
Journal Volume: 26; Journal Issue: C; Journal ID: ISSN 2211-9264
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; 42 ENGINEERING; Microalgae; Catalyst; Biocrude; Hydrothermal liquefaction; Metal; Demetallation

Citation Formats

Jiang, Jimeng, and Savage, Phillip E. Influence of process conditions and interventions on metals content in biocrude from hydrothermal liquefaction of microalgae. United States: N. p., 2017. Web. doi:10.1016/j.algal.2017.07.012.
Jiang, Jimeng, & Savage, Phillip E. Influence of process conditions and interventions on metals content in biocrude from hydrothermal liquefaction of microalgae. United States. doi:10.1016/j.algal.2017.07.012.
Jiang, Jimeng, and Savage, Phillip E. 2017. "Influence of process conditions and interventions on metals content in biocrude from hydrothermal liquefaction of microalgae". United States. doi:10.1016/j.algal.2017.07.012.
@article{osti_1415271,
title = {Influence of process conditions and interventions on metals content in biocrude from hydrothermal liquefaction of microalgae},
author = {Jiang, Jimeng and Savage, Phillip E.},
abstractNote = {We determined how different reaction conditions influence the metals contents in biocrude oil and other product fractions from hydrothermal liquefaction (HTL) of microalgae. We then assessed the effect of using different solvents for biocrude recovery and adding catalysts on the metal content in the biocrude. The Fe content was lower and the Na content higher in biocrude produced at higher temperature (400 vs 350 °C) and longer holding time (60 vs 3 min). The Fe and Na contents were reduced over 50% and 95%, respectively, by use of methyl tert-butyl ether (MTBE ) rather than dichloromethane as the organic solvent for biocrude recovery and they were reduced over 98% via additional application of a supported Ni catalyst during HTL. Finally, this work demonstrates that the hydrothermal treatment conditions influence the metal content in biocrude and that judicious selection of solvent and catalyst can lead to significant reduction in the metal content in biocrude.},
doi = {10.1016/j.algal.2017.07.012},
journal = {Algal Research},
number = C,
volume = 26,
place = {United States},
year = 2017,
month = 7
}

Journal Article:
Free Publicly Available Full Text
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  • Hydrothermal liquefaction (HTL) uses water under elevated temperatures and pressures (200–350 °C, 5–20 MPa) to convert biomass into liquid “biocrude” oil. Despite extensive reports on factors influencing microalgae cell composition during cultivation and separate reports on HTL products linked to cell composition, the field still lacks a quantitative model to predict HTL conversion product yield and qualities from feedstock biochemical composition; the tailoring of microalgae feedstock for downstream conversion is a unique and critical aspect of microalgae biofuels that must be leveraged upon for optimization of the whole process. This study developed predictive relationships for HTL biocrude yield and othermore » conversion product characteristics based on HTL of Nannochloropsis oculata batches harvested with a wide range of compositions (23–59% dw lipids, 58–17% dw proteins, 12–22% dw carbohydrates) and a defatted batch (0% dw lipids, 75% dw proteins, 19% dw carbohydrates). HTL biocrude yield (33–68% dw) and carbon distribution (49–83%) increased in proportion to the fatty acid (FA) content. A component additivity model (predicting biocrude yield from lipid, protein, and carbohydrates) was more accurate predicting literature yields for diverse microalgae species than previous additivity models derived from model compounds. FA profiling of the biocrude product showed strong links to the initial feedstock FA profile of the lipid component, demonstrating that HTL acts as a water-based extraction process for FAs; the remainder non-FA structural components could be represented using the defatted batch. These findings were used to introduce a new FA-based model that predicts biocrude oil yields along with other critical parameters, and is capable of adjusting for the wide variations in HTL methodology and microalgae species through the defatted batch. Lastly, the FA model was linked to an upstream cultivation model (Phototrophic Process Model), providing for the first time an integrated modeling framework to overcome a critical barrier to microalgae-derived HTL biofuels and enable predictive analysis of the overall microalgal-to-biofuel process.« less
  • Cited by 4
  • We provide a direct and detailed comparison of the chemical composition of petroleum crude oil (from the Gulf of Mexico), shale oil, and three biocrudes (i.e., clean pine, microalgae Chlorella sp., and sewage sludge feedstocks) generated by hydrothermal liquefaction (HTL). Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) reveals that HTL biocrudes are compositionally more similar to shale oil than petroleum crude oil and that only a few heteroatom classes (e.g., N1, N2, N1O1, and O1) are common to organic sediment- and biomass-derived oils. All HTL biocrudes contain a diverse range of oxygen-containing compounds when compared tomore » either petroleum crude or shale oil. Overall, petroleum crude and shale oil are compositionally dissimilar to HTL oils, and >85% of the elemental compositions identified within the positive-ion electrospray (ESI) mass spectra of the HTL biocrudes were not present in either the petroleum crude or shale oil (>43% for negative-ion ESI). Direct comparison of the heteroatom classes that are common to both organic sedimentand biomass-derived oils shows that HTL biocrudes generally contain species with both smaller core structures and a lower degree of alkylation relative to either the petroleum crude or the shale oil. Three-dimensional plots of carbon number versus molecular double bond equivalents (with observed abundance as the third dimension) for abundant molecular classes reveal the specific relationship of the composition of HTL biocrudes to petroleum and shale oils to inform the possible incorporation of these oils into refinery operations as a partial amendment to conventional petroleum feeds.« less
  • Our SRI International (SRI) team has developed a new two-step hydrothermal liquefaction (HTL) process to convert wet algal biomass into biocrude oil. The first step in the process (low-temperature HTL or HTL1) yields crude oil but, most importantly, it selectively dissolves nitrogen-containing compounds in the aqueous phase. Once the oil and the aqueous phase are separated, the low-nitrogen soft solids left behind can be taken to the second step (high-temperature HTL or HTL2) for full conversion to biocrude. HTL2 will hence yield low-nitrogen biocrude, which can be hydro-processed to yield transportation fuels. The expected high carbon yield and low nitrogenmore » content can lead to a transportation fuel from algae that avoids two problems common to existing algae-to-fuel processes: (1) poisoning of the hydro-processing catalyst; and (2) inefficient conversion of algae-to-liquid fuels. The process we studied would yield a new route to strategic energy production from domestic sources.« less
  • This review describes the recent results in hydrothermal liquefaction (HTL) of biomass in continuous-flow processing systems. Although much has been published about batch reactor tests of biomass HTL, there is only limited information yet available on continuous-flow tests, which can provide a more reasonable basis for process design and scale-up for commercialization. High-moisture biomass feedstocks are the most likely to be used in HTL. These materials are described and results of their processing are discussed. Engineered systems for HTL are described however they are of limited size and do not yet approach a demonstration scale of operation. With the resultsmore » available process models have been developed and mass and energy balances determined. From these models process costs have been calculated and provide some optimism as to the commercial likelihood of the technology.« less