Experimental-based mechanistic study and optimization of hydrothermal liquefaction of anaerobic digestates

Abstract

Valorization of agricultural and food waste digestates is crucial for sustainable waste management to reduce environmental impacts and improve the economics of commercial farms. Hydrothermal liquefaction (HTL) of anaerobic digestates...

Thermodynamics and Kinetics of Struvite Crystallization from Hydrothermal Liquefaction Aqueous-Phase Considering Hydroxyapatite and Organics Coprecipitation

“…Four HTL-APs were used as stock solutions in this study. The details of their preparation are reported in our previous work . Briefly, four HTL-AP solutions were selected to represent HTL processing of four representative synthetic anaerobic digestates with varying salt content and cellulose-to-lignin ratios.…”

Citrus limetta fruit waste management by liquefaction using hydrogen-donor solvent

“…The conversion of wet biomass at moderate temperature range (280-375 °C) in water and high pressure range to obtain desirable liquid (biocrude) having a high energy content, solid (biochar), and gaseous products is called hydrothermal liquefaction (HTL). [8][9][10] The biocrude is a composite blend of compounds, while biochar represents the char that is insoluble in organic solvents. The separation of the biocrude and char is conducted using an organic solvent in laboratoryscale operations.…”

Probing elemental speciation in hydrochar produced from hydrothermal liquefaction of anaerobic digestates using quantitative X-ray diffraction

“…The rationale for the selection of these compounds was explained in an earlier study. 2 In the model digestate mixture, the total content of alkaline lignin and microcrystalline cellulose was maintained at 8 wt%, 48 the total content of glutamic acid and ammonium-acetate was kept constant at 3 wt% (with NH 3 -N to organic-N molar ratio of 3 : 1), 49 and the inorganic content was xed at 5 wt% (equivalent to 31% ash content on dry matter basis). 48 The cellulose-tolignin ratio was varied between 0.2-1.8 according to the reported values in the literature for anaerobic digestate.…”

“…32 The quantication following WPF and Rietveld renement was carried out by minimizing the weighted residual variance (R WP , see eqn (1)) between the measured and calculated intensities at each point (i.e., the 2q step) in the pattern. The minimization aimed to reach the expected R WP value (R WP,expected ) calculated using eqn (2).…”

“…4 In addition, HTL produces a solid carbonaceous coproduct called hydrochar with relatively similar carbon and energy content to brown coal (lignite) and comparable nutrient content to low-grade phosphate rock. 5 Hydrochar formation is considered disadvantageous from HTL operational perspective since it can adsorb 55-80% of the total biocrude oil produced, 2,6 leading to a requirement of ltration followed by extraction using non-polar organic solvent to recover the biocrude. Because the addition of these two processes increases the HTL operational cost, efforts have been made to suppress hydrochar formation during HTL.…”