Life cycle comparison of hydrothermal liquefaction and lipid extraction pathways to renewable diesel from algae

This study aims to produce renewable diesel and biopriviliged chemicals from microalgae that can thrive in wastewater environment. <i>Spirulina</i> (SP) was converted into biocrude oil at 300ºC for a 30-minute reaction time via hydrothermal liquefaction (HTL). Next, fractional distillation was used to separate SP-derived biocrude oil into different distillates. It was found that 62% of the viscous SP-derived biocrude oil can be separated into liquids at about 270ºC (steam temperature of the distillation). Physicochemical characterizations, including density, viscosity, acidity, elemental compositions, higher heating values and chemical compositions, were carried out with the distillates separated from SP-derived biocrude oil. These analyses showed that 15% distillates could be used as renewable diesel because they have similar heating values (43-46 MJ/kg) and carbon numbers (ranging from C8 to C18) to petroleum diesel. The Van Krevelan diagram of the distillates suggests that deoxygenation was effectively achieved by fractional distillation. In addition, GC-MS analysis indicates that some distillates contain biopriviliged chemicals like aromatics, phenols and fatty nitriles that can be used as commodity chemicals. An algal biorefinery roadmap was proposed based on the analyses of different distillates from the SP-derived biocrude oil. Finally, the fuel specification analysis was conducted with the drop-in renewable diesel, which was prepared with 10 vol.% (HTL10) distillates and 90 vol.% petroleum diesel. According to the fuel specification analysis, HTL10 exhibited a qualified lubricity (<520 µm), acidity (<0.3 mg KOH/g) and oxidation stability (>6 hr), as well as a comparable net heat of combustion (1% lower), ash content (29% lower) and viscosity (17% lower) to those of petroleum diesel. Ultimately, it is expected that this study can provide insights for potential application of algal biocrude oil converted via HTL.

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Exergy analysis of conventional and hydrothermal liquefaction–esterification processes of microalgae for biodiesel production

Open Chemistry ◽

10.1515/chem-2020-0132 ◽

2020 ◽

Vol 18 (1) ◽

pp. 874-881

Author(s):

Laras Prasakti ◽

Sangga Hadi Pratama ◽

Ardian Fauzi ◽

Yano Surya Pradana ◽

Arief Budiman ◽

...

Keyword(s):

Renewable Energy ◽

Exergy Analysis ◽

Lipid Extraction ◽

Hydrothermal Liquefaction ◽

Raw Material ◽

Biodiesel Production ◽

Exergy Loss ◽

Thermochemical Conversion ◽

Third Generation ◽

Land Utilization

AbstractAs fossil fuels were depleting at an alarming rate, the development of renewable energy has become necessary. One of the promising renewable energy to be used is biodiesel. The interest in using third-generation feedstock, which is microalgae, is rapidly growing. The use of third-generation biodiesel feedstock will be more beneficial as it does not compete with food crop use and land utilization. The advantageous characteristic which sets microalgae apart from other biomass sources is that microalgae have high biomass yield. Conventionally, microalgae biodiesel is produced by lipid extraction followed by transesterification. In this study, combination process between hydrothermal liquefaction (HTL) and esterification is explored. The HTL process is one of the biomass thermochemical conversion methods to produce liquid fuel. In this study, the HTL process will be coupled with esterification, which takes fatty acid from HTL as raw material for producing biodiesel. Both the processes will be studied by simulating with Aspen Plus and thermodynamic analysis in terms of energy and exergy. Based on the simulation process, it was reported that both processes demand similar energy consumption. However, exergy analysis shows that total exergy loss of conventional exergy loss is greater than the HTL-esterification process.

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Renewable diesel via hydrothermal liquefaction of oleaginous yeast and residual lignin from bioconversion of corn stover

Applied Energy ◽

10.1016/j.apenergy.2018.09.115 ◽

2019 ◽

Vol 233-234 ◽

pp. 840-853 ◽

Cited By ~ 10

Author(s):

James R. Collett ◽

Justin M. Billing ◽

Pimphan A. Meyer ◽

Andrew J. Schmidt ◽

A. Brook Remington ◽

...

Keyword(s):

Corn Stover ◽

Oleaginous Yeast ◽

Hydrothermal Liquefaction ◽

Residual Lignin ◽

Renewable Diesel

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Life cycle assessment of novel technologies for algae harvesting and oil extraction in the renewable diesel pathway

Algal Research ◽

10.1016/j.algal.2018.12.005 ◽

2019 ◽

Vol 37 ◽

pp. 248-259 ◽

Cited By ~ 12

Author(s):

Rui Shi ◽

Robert M. Handler ◽

David R. Shonnard

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Oil Extraction ◽

Renewable Diesel ◽

Novel Technologies

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Evaluating the Impacts of ACP Management on the Energy Performance of Hydrothermal Liquefaction via Nutrient Recovery

Energies ◽

10.3390/en12040729 ◽

2019 ◽

Vol 12 (4) ◽

pp. 729 ◽

Cited By ~ 3

Author(s):

Sarah Bauer ◽

Fangwei Cheng ◽

Lisa Colosi

Keyword(s):

Life Cycle ◽

Energy Performance ◽

Hydrothermal Liquefaction ◽

Liquid Fuels ◽

Precipitation Process ◽

Net Energy ◽

Modeling Framework ◽

Energy Return On Investment ◽

Theoretical Yield ◽

Struvite Precipitation

Hydrothermal liquefaction (HTL) is of interest in producing liquid fuels from organic waste, but the process also creates appreciable quantities of aqueous co-product (ACP) containing high concentrations of regulated wastewater pollutants (e.g., organic carbon, nitrogen (N), and phosphorus (P)). Previous literature has not emphasized characterization, management, or possible valorization of ACP wastewaters. This study aims to evaluate one possible approach to ACP management via recovery of valuable scarce materials. Equilibrium modeling was performed to estimate theoretical yields of struvite (MgNH4PO4·6H2O) from ACP samples arising from HTL processing of selected waste feedstocks. Experimental analyses were conducted to evaluate the accuracy of theoretical yield estimates. Adjusted yields were then incorporated into a life-cycle energy modeling framework to compute energy return on investment (EROI) for the struvite precipitation process as part of the overall HTL life-cycle. Observed struvite yields and residual P concentrations were consistent with theoretical modeling results; however, residual N concentrations were lower than model estimates because of the volatilization of ammonia gas. EROI calculations reveal that struvite recovery is a net-energy producing process, but that this benefit offers little to no improvement in EROI performance for the overall HTL life-cycle. In contrast, corresponding economic analysis suggests that struvite precipitation may be economically appealing.

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