Aqueous phase recycling in catalytic hydrothermal liquefaction for algal biomass and the effect on elemental accumulation and energy efficiency

JOURNAL OF CLEANER PRODUCTION

卷:289

Article

Taghipour, Alireza¹  Hornung, Ursel⁴  Ramirez, Jerome Atillo^1,3  Brown, Richard John^1,2  Rainey, Thomas James^1,2 

[1] Queensland Univ Technol, Sci & Engn Fac, Sch Mech Med & Proc Engn, 2 George St, Brisbane, Qld 4000, Australia

[2] Queensland Univ Technol, Biofuel Engine Res Facil, 2 George St, Brisbane, Qld 4000, Australia

[3] Queensland Univ Technol, Inst Future Environm, Ctr Agr & Bioecon, Brisbane, Qld, Australia

[4] Karlsruhe Inst Technol KIT, Inst Catalysis Res & Technol IKFT, Hermann-von-Helmoltz-Pl 1, D-76344 Eggenstein Leopoldshafen, Germany

关键词: Biomass;    Aqueous phase;    Catalytic hydrothermal liquefaction (HTL);    Biofuel;    Recycling;   

DOI  :  10.1016/j.jclepro.2020.125582

来源: Elsevier

【 摘 要 】

Generating green-based liquid fuels using hydrothermal liquefaction is a promising method for fossil fuel replacement. This study investigates the impact of recycling the aqueous phase in hydrothermal liquefaction processing on fuel yield, quality and energy efficiency using algae as the feedstock. Recycling the aqueous phase in algal hydrothermal liquefaction increased biocrude production yield by 18.9% at 350 degrees C, although a 12.2% increase in the biocrude nitrogen content was observed. In the second recycling, the nitrogen content increased to 17.6%, which is not environmentally favourable for direct usage in diesel engines due to the possible increase in Nitrogen Oxides (NOx) emissions. Recycling the aqueous phase in Spirulina Platensis feedstock liquefaction led to a 19-30% increase in yields for different recycling numbers, which was influenced by increasing the temperature and by applying catalysts. The heterogeneous catalyst showed a considerable increase (17.8%) in yield, a decrease (9.5%) in nitrogen content, and an improved energy consumption recovery by 30.8% after single recycling. However, a slight increase (2.7%) in nitrogen content was observed after recycling twice. It is vital to reduce the amount of energy used in the hydrothermal liquefaction process to be comparable with conventional fuels. Recycling the aqueous phase reduced the energy usage considerably. Applying the homogeneous catalyst and recycling the aqueous phase twice had the highest energy efficiency (36.8%) and production yield (51.4%) for the hydrothermal liquefaction process. The generated aqueous phase in single and double recycling experiments had up to 77% and 166% more phosphate, which may be of interest for agricultural applications. (C) 2020 Elsevier Ltd. All rights reserved.

【 授权许可】

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