Investigation of aqueous phase recycling for improving bio-crude oil yield in hydrothermal liquefaction of algae

Hu, Yingtao; Feng, Shanghuan; Yuan, Zhongshun; Xu, Chunbao; Bassi, Amarjeet

doi:10.1016/j.biortech.2017.05.033

Cited by 102 publications

(41 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because consumption of the alcohol co-solvent is very low, the aqueous product stream is rich in alcohols. However, it has been reported that such recycling can also enrich the nitrogen and oxygen content of the biocrude product [52,67]. Considering the difficulties of recovering and recycling alcohol co-solvents, a preferred approach may be only to use low concentrations of co-solvents (≤10%) and not attempt recovery.…”

Section: Discussionmentioning

confidence: 99%

“…Hu et al [52] examined HTL treatment of Chlorella vulgaris powder at 275 • C for 50 min, using recycled aqueous products as the liquefaction medium. Adding glycerol to the reaction medium reduced biocrude yields compared to that obtained from HTL in pure water.…”

Section: Glycerolmentioning

confidence: 99%

“…Among the numerous reports of HTL using co-solvents, only a few mention solvent recycling [10,47,52,54]. In these studies, the focus is on isolation and re-use of the aqueous products as a liquefaction medium rather than on the recovery of the alcohol solvents from the aqueous products.…”

Section: Glycerolmentioning

confidence: 99%

See 2 more Smart Citations

Use of Co-Solvents in Hydrothermal Liquefaction (HTL) of Microalgae

et al. 2019

View full text Add to dashboard Cite

This study reviewed and summarized the literature regarding the use of alcohols during hydrothermal liquefaction (HTL) of algal biomass feedstocks. The use of both pure alcohols and alcohol-water co-solvents were considered. Based upon this review, laboratory experiments were conducted to investigate the impacts of different alcohol co-solvents (ethanol, isopropanol, ethylene glycol, and glycerol) on the HTL treatment of a specific saltwater microalga (Tetraselmis sp.) at two temperatures: 300 °C and 350 °C. Based on their performance, two co-solvents, isopropanol and ethylene glycol, were selected to explore the effects of varying solvent concentrations and reaction temperatures on product yields and biocrude properties. The type and amount of added alcohol did not significantly affect the biocrude yield or composition. Biocrude yields were in the range of 30–35%, while a nearly constant yield of 21% insoluble products was observed, largely resulting from ash constituents within the algal feedstock. The benefits of using alcohol co-solvents (especially isopropanol) were the reduced viscosity of the biocrude products and reduced rates of viscosity increase with biocrude aging. These effects were attributed mainly to the physical properties of the co-solvent mixtures (solubility, polarity, density, etc.) rather than chemical processes. Under the reaction conditions used, there was no evidence that the co-solvents participated in biocrude production by means of hydrogen donation or other chemical processes. Recovery and recycling of the co-solvent present various challenges, depending upon the type and amount of the co-solvent that is used. For example, glycol solvents are recovered nearly completely within the aqueous product stream, whereas simple alcohols are partitioned between the biocrude and aqueous product streams. In commercial applications, the slight benefits provided by the use of co-solvents must be balanced by the challenges of co-solvent recovery and recycling.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Glycerolmentioning

confidence: 99%

See 1 more Smart Citation

Use of Co-Solvents in Hydrothermal Liquefaction (HTL) of Microalgae

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Direct recycling of the aqueous phase within the HTL system is one potential route to value addition, demonstrated successfully for microalgae . Recycling of aqueous‐phase carbon was also shown to increase the bio‐crude production from Gracilaria gracilis and Cladophora glomerata macroalgae, although the effect on bio‐crude elemental composition was not discussed .…”

Section: Hydrothermal Liquefactionmentioning

confidence: 99%

Hydrothermal liquefaction of macroalgae for the production of renewable biofuels

Raikova

Allen

Chuck

2019

Biofuels Bioprod Bioref

View full text Add to dashboard Cite

In all biorefinery systems, excess water represents a key challenge, and its removal by drying is often a necessary and crucial pre-treatment. Second-generation feedstocks have often fallen at this hurdle, particularly microalgae-derived biomasses, which require extensive (and costly) dewatering. Hydrothermal liquefaction (HTL) has gained increasing attention in recent years as a technology that uses the water present in the feedstock as a versatile reaction medium, which functions as a solvent, reactant, and catalyst for a cascade of organic reactions. Converting organic biomasses into oil, aqueous, solid, and gas fractions, the development of HTL provides the opportunity to exploit previously unsuitable biomasses in a versatile bio-refinery approach. Marine macroalgae (seaweeds) offer a sustainable source of renewable biomass, which require no land or freshwater to cultivate or harvest. With 70% of the surface of the planet covered in seawater and levels of eutrophication increasing, seaweeds are an underutilized resource with excellent potential for relieving the pressure on fossil resources. Hitherto, this exploitation has been hindered by a lack of suitable and economical processing tools. Here we review the potential for applying HTL to processing marine macroalgae and discuss the potential products and services that can be derived from this potential biorefinery system.

show abstract

“…Typically, ammonium-N is more bioavailable than other common forms of nitrogen (i.e., nitrate, organic nitrogen, etc.) to the microalgae (Hu et al 2017). In addition, some microalgae are capable of selectively consuming the amino substituents of multiple cyclic organic compounds (López Barreiro et al 2015).…”

Section: The Potential Recycling Of the Aqueous Phase Liquid (Apl)mentioning

confidence: 99%

Comparison of biocrude oil production from self-settling and non-settling microalgae biomass produced in the Qatari desert environment

Das

Thaher

Khan

et al. 2019

Int. J. Environ. Sci. Technol.

View full text Add to dashboard Cite

The present study investigated the growth, harvesting, biocrude conversion, and recycling of the HTL aqueous phase for one self-settling (i.e., Chlorocystis sp.) and another non-settling (i.e., Picochlorum sp.) marine microalgae. Both the strains were grown simultaneously in 2 identical 25,000-L raceway ponds in the Qatari desert. The cell size of Picochlorum sp. was small (2-3 µm), and its biomass was harvested using a centrifuge. Cells of Chlorocystis sp. (6-9 µm) formed flocs that settled spontaneously in a sedimentation chamber. Harvested biomass of these two strains was then converted to biocrude oil, using a 500-mL Parr reactor. The biocrude yield of Picochlorum sp. and Chlorocystis sp. was 39.6 ± 1.15% and 34.8 ± 1.65%, respectively. The energy content of the biocrude oil was 32.78 and 33.38 MJ/kg for Chlorocystis sp. and Picochlorum sp., respectively. Both the strains were capable of efficiently utilizing more than 95% nitrogen of the HTL aqueous phase. Although lower biocrude yield was obtained from Chlorocystis sp., compared to Picochlorum sp., harvesting of Chlorocystis sp. would require much lower energy compared to Picochlorum sp. Therefore, a self-settling microalgae (e.g., Chlorocystis sp.) could potentially be a better candidate, over non-settling microalgae, for producing biofuel feedstock.

show abstract

Investigation of aqueous phase recycling for improving bio-crude oil yield in hydrothermal liquefaction of algae

Cited by 102 publications

References 32 publications

Use of Co-Solvents in Hydrothermal Liquefaction (HTL) of Microalgae

Use of Co-Solvents in Hydrothermal Liquefaction (HTL) of Microalgae

Hydrothermal liquefaction of macroalgae for the production of renewable biofuels

Comparison of biocrude oil production from self-settling and non-settling microalgae biomass produced in the Qatari desert environment

Contact Info

Product

Resources

About