Improved Quality Bio-Crude from Hydrothermal Liquefaction of Oak Wood Assisted by Zero-Valent Metals

Abstract

The production of bio-fuels is becoming one of the biggest challenges of this decade. In this context, the interest on hydrothermal liquefaction (HTL) is continuously growing. In this work, the HTL of oak wood to produce a high-quality bio-crude is proposed. The effect of the use of zero-valent metals (ZVMs) as hydrogen producers (Fe and Zn) and hydrodeoxygenation catalysts (Ni and Co) on bio-crude quality is investigated. The tests were conducted at 330 °C in micro-batch reactors at different reaction times in the presence of ZVMs. Fe and Zn are oxidized by subcritical water producing active hydrogen, which is used to stabilize biomass fragments during the process and to be used in hydrodeoxygenation reactions in the presence of Ni and Co. The results show that the use of hydrogen producers significantly affects bio-crude yields, which increase by 20% with respect to the blank test when Fe is used. Furthermore, the synergic effect between the hydrogen producers (Fe and Zn) and the catalysts (Ni and Co) was tested. The results pointed out an enhancement of the bio-crude quality with an increase in the H/C ratio and a decrease in the O/C ratio, and also, looking at the bio-crude composition, the hydrogenation extent is clearly proven, for example, 2-cyclopenten-1-ones increase at the expense of furan derivatives.

Hydrotreatment of Supercritical Carbon Dioxide Extracts of Hydrothermal Liquefaction Lignocellulosic Biocrude

“…A few single-ring (benzenes) and several 2- and 3-ring aromatic hydrocarbons (PAH) were also found. In general, these chemical classes are common in HTL biocrudes produced from woody biomass. − The results are in good agreement with previous works, where a more detailed discussion on the chemical characterization is presented together with quantitative data. − The relative distribution of these chemical classes is similar in the two feeds (Table S4 in the Supporting Information). However, it is important to note that the mass fraction of the volatile (GC–MS detectable) fraction of the SE can be up to twice as large as that of the BC (e.g., 19 and 40 wt % for BC and SE, respectively). , …”

A review on thermochemical based biorefinery catalyst development progress

“…36 Some of these metals, which have been used during the HTL of biomass, are zinc, copper, iron, nickel, cobalt, manganese, palladium and ruthenium. 36 In Table 12, [329][330][331][332][333][334][335][336][337][338][339][340][341][342] the range of 33-36 MJ kg −1 (the highest was 35.65 MJ kg −1 for the bio-oil from the blank experiment and the lowest was 33.24 MJ kg −1 for Mn). The hydrothermal liquefaction of pine sawdust was performed in an autoclave by Xu et al 91 in the presence of Ni/HZSM-5 (Ni loading of 5 and 10 wt%) at 300 °C and 1680-1900 psig.…”

“…The bio-oil obtained included two phases and the HHV of the light phase was 27.19 MJ kg −1 and the HHV of the heavy phase was 31.83 MJ kg −1 . Tai et al 332 performed the hydrothermal liquefaction of oak wood in a tubular micro-reactor at 330 °C. Ni, Co, Fe and Zn were used as the catalysts.…”

Effects of Stepwise Microwave Synergistic Process Water Recirculation During Hydrothermal Carbonization on Properties of Wheat Straw

“…The result was higher than the results of Uddin et al (2014). Research has shown that the cellulose and hemicellulose in biomass decomposed into soluble sugar, and the lignin degraded into aromatic alcohol in the process of HTC (de Caprariis et al, 2021;Tai et al, 2021). During PWR, these decomposition products were condensed and polymerized, then deposited on the surface of hydrochar, which led to the increase of mass yield of hydrochar (Titirici and Antonietti, 2010).…”