Mild Hydrothermal Liquefaction of High Water Content Agricultural Residue for Bio-Crude Oil Production: A Parametric Study

Abstract

Depleting petroleum reserves together with the associated environmental concerns have intensified the exploration of alternatives to petroleum. Wet food processing wastes present promising bioresources for liquid fuel production via hydrothermal liquefaction (HTL) followed by additional upgrading. In this study, tomato plant waste (TPW) was utilized as a feedstock for the production of bio-crude oils via HTL at medium-temperature (220-280 • C) in water or a water-ethanol (17/3, v/v) medium in a 600 mL autoclave reactor. Effects of various operating parameters, such as catalysts (H 2 SO 4 or KOH), reaction time (15-60 min) and reaction temperature (220-280 • C) on product yields were investigated. This study showed that a high yield (45.1 wt%) of bio-crude oil was achieved from HTL of TPW in water-ethanol medium at 250 • C in the presence of acid catalyst H 2 SO 4 . The oil, gas and solid residue (SR) products were analyzed for their chemical and structural properties.

Hydrothermal Liquefaction of Food Waste: Effect of Process Parameters on Product Yields and Chemistry

“…The highest HHV of bio-crude oil (40.2 MJ/kg) was obtained at 295 • C and 30 min (Supplementary Table 1) as carbohydrate and protein compounds were converted to produce bio-crude oil (Cheng et al, 2018), which is in line with the HHV of bio-crude oils derived from food waste in previous studies (32-41 MJ/kg) (Zastrow and Jennings, 2013;Maag et al, 2018;Zhang et al, 2018). The highest energy recovery for food waste bio-crude oil (49.3%) was comparable to recovered energy from HTL of algae (Gai et al, 2014) and other lignocellulose biomass (Cao et al, 2017).…”

“…Hydrothermal liquefaction (HTL) is a thermochemical valorization process that converts many types of biomass into an energy-dense bio-crude oil and co-products: gases, aqueous phase, and char. Among the feedstocks that have been studied are lignocellulosic biomass (Christensen et al, 2014;Zhu et al, 2014;Alhassan et al, 2016;Zhang et al, 2018;Cheng et al, 2020b), micro-and macro-algae (Zhou et al, 2010;Anastasakis and Ross, 2011;Duan and Savage, 2011;Jena et al, 2011;Vardon et al, 2011;Cheng et al, 2018), manure and animal byproducts (Chen et al, 2014;León et al, 2019), sludge from municipal wastewater treatment plants (Snowden-Swan et al, 2016;Kapusta, 2018), and food processing waste (Déniel et al, 2016;Zhang et al, 2018;Bayat et al, 2019). HTL utilizes sub-critical water (200-370 • C; 10-30 MPa) to decompose complex macro-molecules into lowermolecular-weight products that then polymerize into larger compounds that form bio-crude oil.…”

Assessment of Agroforestry Residues: Their Potential within the Biorefinery Context

“…Therefore, based on calorific values of TW and WW, it would not be economically viable to evaporate such an amount of water in order to promote the combustion of them into thermal energy. However, these residues may be concentrated by partial evaporation in order to process them by anaerobic digestion into methane , or by hydrothermal liquefaction into bio-oil . PB and PS can be handled directly as a whole using thermochemical technologies, such as pyrolysis and direct gasification of lignocellulosic biomass …”

“…However, these residues may be concentrated by partial evaporation in order to process them by anaerobic digestion into methane 71,72 or by hydrothermal liquefaction into bio-oil. 73 PB and PS can be handled directly as a whole using thermochemical technologies, such as pyrolysis 74 and direct gasification of lignocellulosic biomass. 75 Bioethanol production through bioprocesses (enzymatic saccharification and fermentation) requires suitable carbonrich substrates, along with the control of other relevant factors, such as temperature, substrate concentration, and pH.…”

Hydrothermal biomass processing for green energy transition: insights derived from principal component analysis of international patents

“…Applying strong alkaline solutions neutralizes the pH and inhibits the formation of organic acids, thus hindering the repolymerization reactions. After applying alkali catalysts to lignocellulosic substrates, bio-crude yields increase by 50 units–135 wt.% ( Haarlemmer et al., 2016 ; Hu et al., 2020 ; Zhang et al., 2018 ).…”