Whole Algae Hydrothermal Liquefaction: 2014 State of Technology

One of the foundations of this work integrates CHG with the HTL system, but cannot achieve its $3 GGE-1 MFSP target, as the cost of HTL with CHG already surpasses $3 GGE-1 without even factoring in the cost of biomass.

“It should be noted that one of the foundations of this work integrates CHG with the HTL system [13], but cannot achieve its $3 GGE -1 MFSP target, as the cost of HTL with CHG already surpasses $3 GGE -1 without even factoring in the cost of biomass.”

Jones et al. (2014) reported an MFSP of $1.19 LGE-1 ($4.49 GGE-1) assuming a biomass purchase price of $430 dry ton-1.

“The model developed in this work was first validated against the original work in Jones et al. (2014), which reported an MFSP (in 2011$) of $1.19 LGE -1 ($4.49 GGE -1 ) assuming a biomass purchase price of $430 dry ton -1 [13].”

Some of the most detailed HTL model assessments to date in Jones et al. (2014) and Knorr et al. (2013) have not yet developed a sensitivity analysis for varying reaction temperature.

“Some of the most detailed HTL model assessments to date in Jones et al. (2014) [13] and Knorr et al. (2013) [24] have not yet developed a sensitivity analysis for varying reaction temperature.”

Biomass price and fuel yield have the greatest effect on the minimum fuel selling price; higher biocrude yields and lower feedstock costs drive down the MFSP considerably.

“Biomass price and fuel yield have the greatest effect on the minimum fuel selling price (MFSP); higher yields of biocrude and lower feedstock costs drive down the MFSP considerably, as demonstrated in sensitivity analyses of HTL in Jones et al. (2014) [13], Zhu et al. (2019) [14], and Gu et al. (2020) [15].”

The HTL system boundary contribution to GWP in Jones et al. (2014) varies between +9.1 and +20.5 g CO2 eq MJ-1 depending on system boundary assumptions.

“The HTL system boundary contribution to GWP in Jones et al. (2014) varies between +9.1 and +20.5 g CO2 eq MJ -1 depending on system boundary assumptions [13]; however, differences in certain assumptions like fuel yield and nutrient recycle are not accounted for.”

The NER equivalent of the HTL plant system boundary is 0.14 in the reference model, reported as fossil energy consumption.

“The NER equivalent of the HTL plant system boundary is 0.14 in the reference model, reported as fossil energy consumption [13].”

The sensitivity analyses in Jones et al. (2014) and Zhu et al. (2019) are performed on the total fuel selling price, which includes the cost of biomass.

“The sensitivity analyses in both Jones et al. (2014) [13] and Zhu et al. (2019) [14] are performed on the total fuel selling price, which includes the cost of biomass.”

Jones et al. (2014) reports an MFSP of $1.26 per liter gasoline equivalent for continuous HTL with biomass purchased at $474 per dry metric ton and a 51% biocrude yield.

“Jones et al. (2014) reports techno-economic assessment (TEA) results based on optimistic cost targets, where biomass is optimistically purchased at $474 per dry metric ton and the continuous HTL process produces a 51% biocrude yield to achieve an MFSP of $1.26 per liter gasoline equivalent (LGE) ($4.77 per gallon gasoline equivalent (GGE)) [13].”

Because of the assumptions used, variable operating costs in this work are not directly comparable with the primary reference literature in Jones et al. (2014).

“Because of these assumptions, variable operating costs were not directly comparable with the primary reference literature in Jones et al. (2014) [13].”

The model developed in this work was validated against Jones et al. (2014).

“The model developed in this work was first validated against the original work in Jones et al. (2014)”

Gravity separation may not sufficiently separate HTL product phases due to biocrude residues lost in the aqueous phase.

“In reality, gravity separation may not sufficiently separate HTL product phases due to the presence of biocrude residues lost in the aqueous phase [13].”

The predictive Soave-Redlich Kwong (PSRK) equation of state has seen precedence in algal HTL literature from Jones et al. (2014).

“A derivative of SRK, the predictive Soave-Redlich Kwong (PSRK) equation of state has seen precedence in algal HTL literature from Jones et al. (2014) [13] 2 .”