Advances in energy systems for valorization of aqueous byproducts generated from hydrothermal processing of biomass and systems thinking

Abstract

Advances in energy systems for the valorization of the aqueous byproduct generated from the hydrothermal processing of biomass: a perspective and review of the recent progress.

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

“…The aqueous phase from HTL of food waste showed a low nitrogen recovery, ranging from 4.5 to 14.8 wt.% (TN = 0.74-1.8 g/L), in agreement with previous studies (Gu et al, 2019). Watson et al (2020) reported that the aqueous phase derived from HTL of lignocellulosic biomass, or a feedstock dominated by carbohydrates, has the lowest nitrogen content (TN average = 0.8 g/l) compared to the aqueous phase from HTL of manure, algae, or sludge due to the low amounts of protein-containing compounds.…”

“…There are various valorization methods for food waste that can result in extraction of value-added compounds (polyphenols, pectin, protein), bio-materials (bio-chemicals, biopolymers, enzymes, single cell proteins, and bio-fertilizers), compost/soil amendments, and biofuels; among the methods are biochemical conversions (anaerobic digestion and fermentation), and thermochemical conversions (pyrolysis, gasification, and hydrothermal liquefaction) (Nawaz et al, 2006;Masmoudi et al, 2008;Sowbhagya and Chitra, 2010;Hassan et al, 2013;Wang et al, 2014;Gu et al, 2019;Cheng et al, 2020a). Two major challenges for composting and other biochemical conversions are the high sensitivity of microorganisms to operating conditions and the long processing times (Pham et al, 2015).…”

Treatment of Hydrothermal-Liquefaction Wastewater with Crossflow UF for Oil and Particle Removal

“…Several technologies have been investigated for the valorization of HTL-WW, such as anaerobic digestion, adsorption (of phenolics and nitrogenous compounds) on activated carbon and hydrothermal gasification (HTG) and catalytic hydrothermal gasification (CHG) [ 4 , 5 , 6 ]. However, these techniques face limitations, such as the toxicity of HTL-WW to anaerobic compounds such as phenols, which originates from highly concentrated inhibitory compounds, the blockage of adsorbent media in activated carbon by particulates, as well as the high temperature, pressure and cost of the catalysts used in CHG [ 7 , 8 , 9 ]. HTL-WW could be treated via the membrane-filtration process, which is becoming an attractive solution due to its low energy consumption and higher filtration flux [ 3 ].…”

Comparative Techno-Economic and Life Cycle Analysis of Water Oxidation and Hydrogen Oxidation at the Anode in a CO2 Electrolysis to Ethylene System

“…Although the simplicity of these designs has the potential to reduce capital costs and improve durability, most demonstrations of membraneless CO 2 electrolysis have been at the microfluidic scale. ,, The high degree of control over laminar flow in microfluidic devices allows for operation at a high current density, narrow electrode separation distances, and low product crossover rates . Demonstrations of membraneless water electrolysis at the centimeter scale found somewhat higher H 2 crossover rates on the order of 1 to 5%. , For systems such as these which employ a water oxidation anode, attempts to operate at higher current densities, larger electrode areas, and narrower electrode separation distances could result in higher crossover rates which create flammable mixtures of H 2 and O 2 gas.…”