TY - JOUR
T1 - Technological advancements in valorisation of industrial effluents employing hydrothermal liquefaction of biomass
T2 - Strategic innovations, barriers and perspectives
AU - Rout, Prangya Ranjan
AU - Goel, Mukesh
AU - Pandey, Daya Shankar
AU - Briggs, Caitlin
AU - Sundramurthy, Venkatesa Prabhu
AU - Halder, Nirmalya
AU - Mohanty, Anee
AU - Mukherjee, Sanjay
AU - Varjani, Sunita
N1 - Funding Information:
The TEA of HTL process has been widely performed for various feedstocks and is well documented in existing literature. For instance, an investigation carried out by Jiang et al. studied the impact of different algae feedstocks on the biocrude production cost from HTL process revealed that the cost of biocrude could vary between $5–16/GGE and is majorly dependent of the feedstock cost, which was $400 to $1800/dry ton (Jiang et al., 2019). The study also concluded that the economic uncertainties for algae conversion via HTL for biocrude production were due to algae composition (high or low lipid content) and capital investment. Another study on sensitivity analysis of algae to biofuels via HTL showed that the ash content and biomass cost has significant influence on the techno-economic viability of the HTL process (DeRose et al., 2019). The study reported a minimum selling price of $10.41/GGE and suggests system improvements to achieve $3.85/GGE. Aierzhati et al. (2021) used pilot-scale experiments to demonstrate the commercial feasibility of a mobile HTL unit for converting food waste into biocrude oil (Aierzhati et al., 2021). The TEA of the process showed a least selling rate of $3.48/GGE. Li et al. (2021) obtained a minimum selling price of $2.65/GGE for HTL of wet waste. The experiments obtained higher yield for a continuous process as compared to batch process. Their work also indicated that controlling the feed moisture and reaction yield can reduce the uncertainties in the minimum selling price by roughly 50% (Li et al., 2021). A report by Pacific Northwest National Lab (PNNL) assessed the minimum fuel selling price of the produced fuel via upgrading the HTL derived biocrude to hydrocarbon fuels to be $2.85 and $2.83 per gasoline-gallon equivalent (GGE) for the aqueous phase with and without NH3 stripping, respectively. The report also acknowledged a reduced MFSP by $0.64/GGE of fuel blend stock compared to the 2020 due to the recent advancement in HTL derived biocrude hydrotreating techniques (Snowden-Swan et al., 2022; Snowden-Swan et al., 2021). To summarise, the reported studies indicated that the feedstock quality, feedstock cost and reactor yield are the primary causes for the economic uncertainties or for the fluctuations observed in the biocrude oil cost. Therefore, a greater control over these factors must be emphasised in future studies. Overall, the TEA outcomes in all these studies support the commercial viability of the HTL process for variety of a feedstock.The authors are thankful to the Thapar Institute of Engineering and Technology (TIET) and Sheffield Hallam University for supporting this work.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2023/1/1
Y1 - 2023/1/1
N2 - Hydrothermal liquefaction (HTL) is identified as a promising thermochemical technique to recover biofuels and bioenergy from waste biomass containing low energy and high moisture content. The wastewater generated during the HTL process (HTWW) are rich in nutrients and organics. The release of the nutrients and organics enriched HTWW would not only contaminate the water bodies but also lead to the loss of valued bioenergy sources, especially in the present time of the energy crisis. Thus, biotechnological as well as physicochemical treatment of HTWW for simultaneous extraction of valuable resources along with reduction in polluting substances has gained significant attention in recent times. Therefore, the treatment of wastewater generated during the HTL of biomass for reduced environmental emission and possible bioenergy recovery is highlighted in this paper. Various technologies for treatment and valorisation of HTWW are reviewed, including anaerobic digestion, microbial fuel cells (MFC), microbial electrolysis cell (MEC), and supercritical water gasification (SCWG). This review paper illustrates that the characteristics of biomass play a pivotal role in the selection process of appropriate technology for the treatment of HTWW. Several HTWW treatment technologies are weighed in terms of their benefits and drawbacks and are thoroughly examined. The integration of these technologies is also discussed. Overall, this study suggests that integrating different methods, techno-economic analysis, and nutrient recovery approaches would be advantageous to researchers in finding way for maximising HTWW valorisation along with reduced environmental pollution.
AB - Hydrothermal liquefaction (HTL) is identified as a promising thermochemical technique to recover biofuels and bioenergy from waste biomass containing low energy and high moisture content. The wastewater generated during the HTL process (HTWW) are rich in nutrients and organics. The release of the nutrients and organics enriched HTWW would not only contaminate the water bodies but also lead to the loss of valued bioenergy sources, especially in the present time of the energy crisis. Thus, biotechnological as well as physicochemical treatment of HTWW for simultaneous extraction of valuable resources along with reduction in polluting substances has gained significant attention in recent times. Therefore, the treatment of wastewater generated during the HTL of biomass for reduced environmental emission and possible bioenergy recovery is highlighted in this paper. Various technologies for treatment and valorisation of HTWW are reviewed, including anaerobic digestion, microbial fuel cells (MFC), microbial electrolysis cell (MEC), and supercritical water gasification (SCWG). This review paper illustrates that the characteristics of biomass play a pivotal role in the selection process of appropriate technology for the treatment of HTWW. Several HTWW treatment technologies are weighed in terms of their benefits and drawbacks and are thoroughly examined. The integration of these technologies is also discussed. Overall, this study suggests that integrating different methods, techno-economic analysis, and nutrient recovery approaches would be advantageous to researchers in finding way for maximising HTWW valorisation along with reduced environmental pollution.
KW - Biomass
KW - Hydrothermal liquefaction
KW - Industrial rejects
KW - Supercritical water gasification
KW - Waste valorisation
UR - http://www.scopus.com/inward/record.url?scp=85142327720&partnerID=8YFLogxK
U2 - 10.1016/j.envpol.2022.120667
DO - 10.1016/j.envpol.2022.120667
M3 - Review article
C2 - 36395914
AN - SCOPUS:85142327720
SN - 0269-7491
VL - 316
JO - Environmental Pollution
JF - Environmental Pollution
M1 - 120667
ER -