Modification of a pilot-scale continuous flow reactor for hydrothermal liquefaction of wet biomass

Cheng, Feng; Doux, Travis Le; Treftz, Brian; Woolf, Scott; Yu, Jicheng; Miller, J G; Jena, Umakanta; Brewer, Catherine E.

doi:10.1016/j.mex.2019.11.019

Cited by 12 publications

(2 citation statements)

References 31 publications

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“…These calculations contain a number of important assumptions that require validation as a part of large-scale field demonstration work. Larger pilot-scale continuous-flow hydrothermal reactors have been deployed for hydrothermal liquefaction of sewage sludge and algal biomass. − Future work is planned to assess the applications of this process for the treatment of concentrates and to remediate PFAS-contaminated soils and sediments.…”

Section: Results and Discussionmentioning

confidence: 99%

Hydrothermal Alkaline Treatment for Destruction of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foam

Hao

Choi

et al. 2021

Environ. Sci. Technol.

117

142

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The widespread use of aqueous film-forming foam (AFFF) for firefighting activities (e.g., fire training to extinguish fuel-based fires at aircraft facilities) has led to extensive groundwater and soil contamination by per-and polyfluoroalkyl substances (PFASs) that are highly recalcitrant to destruction using conventional treatment technologies. This study reports on the hydrothermal alkaline treatment of diverse PFASs present in AFFFs. Quantitative and semiquantitative high-resolution mass spectrometry analyses of PFASs demonstrate a rapid degradation of all 109 PFASs identified in two AFFFs (sulfonate-and fluorotelomer-based formulations) in water amended with an alkali (e.g., 1−5 M NaOH) at near-critical temperature and pressure (350 °C, 16.5 MPa). This includes per-and polyfluoroalkyl acids and a range of acid precursors. Most PFASs were degraded to nondetectable levels within 15 min, and the most recalcitrant perfluoroalkyl sulfonates were degraded within 30 min when treated with 5 M NaOH. 19 F NMR spectroscopic analysis and fluoride ion analysis confirm the near-complete defluorination of PFASs in both dilute and concentrated AFFF mixtures, and no stable volatile organofluorine species were detected in reactor headspace gases by the gas chromatography−mass spectrometry analysis. These findings indicate a significant potential for application of hydrothermal treatment technologies to manage PFAS waste streams, including on-site treatment of unused AFFF chemical stockpiles, investigation-derived wastes, and concentrated source zone materials.

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Section: Results and Discussionmentioning

confidence: 99%

Hydrothermal Alkaline Treatment for Destruction of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foam

Hao

Choi

et al. 2021

Environ. Sci. Technol.

117

142

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“…In the continuous HTL mode, the optimum flow rates have not yet been well-defined due to unwanted clogging problems that occurred in high-pressure pumps and conversion reactors at pilot-scale platforms. However, based on the pilot-scale results, the suitable flow rate is likely to be in the range of 0.5–2.0 m/s to ensure the homogeneity of the feeding slurry and effectively prevent potential clogging issues. − Moreover, a continuously stirred tank reactor (CSTR) has been developed to solve the clogging issue by utilizing an impeller/magnetic stir bar to assist rotation from about 100 to 600 rpm, consequently introducing linear flow movement at a rate of less than 1 m/s over the reactor alloy surface. , From corrosion perspective, flow-accelerated corrosion (FAC) is a concern on the selection of suitable constructional alloys, especially for low-alloyed steels (such as P91 steel), for the construction of continuous HTL plants. During FAC corrosion, normally protective oxide layers on steels exhibit high dissolution rates in the fluids with high flow rates, making the oxide layer become thinner and less protective.…”

Section: Introductionmentioning

confidence: 99%

Influence of Major Operating Parameters (Temperature, Pressure, and Flow Rate) on the Corrosion of Candidate Alloys for the Construction of Hydrothermal Liquefaction Biorefining Reactors

2022

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Hydrothermal liquefaction (HTL) is a promising thermochemical technology to convert wet biomass and biowastes into marketable bio-oils and biochemicals in an environmentally friendly manner. However, industrial deployment of this technology has been significantly hindered due to very limited materials and corrosion knowledge for the selection of appropriate alloys for the construction and long-term safe operation of HTL reactors. This study investigated the influence of operating temperature, pressure, and flow rate on the corrosion modes and extents of two candidate constructional steels (SS310 and P91) using high-temperature static autoclaves and environmental loop facilities under representative HTL conversion conditions, followed by post-mortem X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy/energy-dispersive spectroscopy, focused ion beam, and transmission electron microscopy characterizations of the formed corrosion products. The two steels experienced general and/or nodular oxidation in hot HTL water at 250–365 °C. Increasing temperature and flow rate resulted in a noticeable increase in the corrosion rate of P91. For SS310, there is critical temperature point (around 310 °C) above which its corrosion rate decreases with temperature. Increasing flow rate suppressed the nodular oxidation of SS310 and consequently led to a decrease in the corrosion rate. Increasing pressure from 9.8 to 25 MPa promoted the oxide formation on SS310 while caused an increased dissolution rate of the corrosion layer grown on P91 steel at 310 °C. In the simulated HTL conversion environments, the corrosion layer on P91 was mainly composed of magnetite (Fe3O4) and chromite (Fe3–x Cr x O4), while a compact and protective inner Cr-enriched layer was formed on SS310 along with the presence of other cations. Related corrosion mechanisms were also discussed and proposed.

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Hydrothermal liquefaction of wet microalgal biomass for biofuels and platform chemicals: advances and future prospects

Deepika,

Mrinal,

Pohrmen

et al. 2024

Discov Appl Sci

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Recent advances in hydrothermal liquefaction (HTL) have established this biomass conversion technology as a potent tool for the effective valorization and energy densification of varied feedstocks, ranging from lignocelluloses to microalgae and organic wastes. Emphasizing its application across biomass types, this exploration delves into the evolving landscape of HTL. Microalgae, recognized as a promising feedstock, offer a rich source of biomolecules, including lipids, carbohydrates, and proteins, making them particularly attractive for biofuel production. The comprehensive review explores the biofuel products and platform chemicals obtained through HTL of microalgae, delving into biodiesel production, bio-oil composition, characteristics, and to produce high-valued by-products. Challenges and limitations, such as reactor design, scalability issues, and the impact of microalgal composition on yields, are critically analyzed. The future prospects and research directions section envision advancements in HTL technology, integration with biorefinery processes, and the exploration of hybrid approaches for enhanced biofuel production. Overall, the paper emphasizes the promising potential of HTL for wet microalgal biomass and underscores the need for continued research to overcome existing challenges and unlock further opportunities in sustainable biofuel and platform chemical production.

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Modification of a pilot-scale continuous flow reactor for hydrothermal liquefaction of wet biomass

Abstract: Graphical abstract

Cited by 12 publications

References 31 publications

Hydrothermal Alkaline Treatment for Destruction of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foam

Hydrothermal Alkaline Treatment for Destruction of Per- and Polyfluoroalkyl Substances in Aqueous Film-Forming Foam

Influence of Major Operating Parameters (Temperature, Pressure, and Flow Rate) on the Corrosion of Candidate Alloys for the Construction of Hydrothermal Liquefaction Biorefining Reactors

Hydrothermal liquefaction of wet microalgal biomass for biofuels and platform chemicals: advances and future prospects

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