Mechanism of the Fe-Assisted Hydrothermal Liquefaction of Lignocellulosic Biomass

Miyata, Yoshinori; Sagata, Kunimasa; Yamazaki, Yoshiko; Teramura, Hiroshi; Hirano, Yoshiaki; Ogino, Chiaki; Kita, Yasuhiro

doi:10.1021/acs.iecr.8b03725

Cited by 36 publications

(9 citation statements)

References 42 publications

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“…Thus, the Zn–water redox reaction with the consequent active hydrogen production begins during the transient increase in temperature before reaching the target one of 330 °C. This allows large amounts of hemicellulose and cellulose degradation products to react with the so-produced active hydrogen, giving rise mainly to water-soluble organics like 2-cyclopenten-1-ones, 1,2-butanediol, hydroxyacetone, and 1,2-ethanediol (25341 mg/L) and thus limiting the reactions of bio-crude formation through the combination of the cellulose and hemicellulose degradation compounds. , When the temperature reaches 330 °C, the active hydrogen was already totally emitted and partially consumed in the stabilization of cellulose and hemicellulose fragments, and therefore, when lignin is decomposed producing methoxy-alkylphenols monomers, no active hydrogen is available. The lignin derivatives undergo condensation reaction to form high-molecular-weight compounds, resulting in major char yield. − The active hydrogen that does not react with biomass intermediates forms gaseous hydrogen, which is not active in the absence of a catalyst .…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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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.

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Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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“…Moreover, commercial carbohydrates and enzymatically isolated lignin were employed as model compounds to elucidate the reaction mechanism of the Fe-assisted hydrothermal liquefaction system, and plausible reaction pathways were proposed by the authors, as illustrated in Figure . In this work, the oxidized Fe promoted the retro-aldol condensation of sugars, while the repolymerization reaction of the reactive intermediates could be suppressed by Fe.…”

Section: Zero-valent Metals As In Situ Hydrogen Donorsmentioning

confidence: 87%

Section: Zero-valent Metals As In Situ Hydrogen Donorsmentioning

confidence: 99%

Recent Advances in Hydroliquefaction of Biomass for Bio-oil Production Using In Situ Hydrogen Donors

Zhao

Gao

et al. 2020

Ind. Eng. Chem. Res.

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With the rapid growth of energy demand and environmental concerns associated with traditional fossil fuels, renewable and sustainable energy sources have attracted intensive research attention in recent years. Biomass is considered as one of the most promising alternative energy resources due to its many advantages including abundance, renewability, carbon neutrality, and worldwide distribution. Liquefaction is an efficient thermochemical conversion route for the production of bioderived fuels and chemicals under mild reaction conditions. In addition, this process does not require energy-intensive drying as a preprocessing step of the wet biomass feedstocks. Nevertheless, subsequent hydrogenation and upgrading treatment of the bio-oil with high oxygen content are imperative for practical applications mainly for improving the calorific value of the bio-oil. The cost and safety issues of external hydrogen are main obstacles for the liquefaction-upgrading route, which can be somewhat offset by the use of in situ hydrogen. The research on in situ hydrogen generation and use for biomass liquefaction is nascent. Therefore, the latest research developments on hydroliquefaction of biomass feedstocks in the presence of various in situ hydrogen donors are reviewed in this article. Several commonly applied in situ hydrogen donors including formic acid, alcohols (isopropyl alcohol, methanol and ethanol), and zerovalent metals (zinc, aluminum, iron, etc.) are discussed in detail focusing mainly on their influence on the distribution of liquefied products and the mechanisms of hydrogen-donation/hydrogenation reactions. Moreover, future research directions toward the commercial applications of biomass liquefaction technology with in situ hydrogenation strategies are presented.

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“…Many studies suggested other possible options such as the catalytic cracking of the aqueous phase product to obtain valuable chemicals such as olefins and aromatic hydrocarbons such as benzene, toluene, and xylene. Miyata et al [172] developed a method to separate the light water-soluble fraction (by freeze drying) and heavy water-soluble fraction (by water removal) and conducted catalytic cracking on separated fractions, producing an olefins + BTX yield of 49% and 14%, respectively.…”

Section: Aqueous Phasementioning

confidence: 99%

A Review of Hydrothermal Liquefaction of Biomass for Biofuels Production with a Special Focus on the Effect of Process Parameters, Co-Solvents, and Extraction Solvents

et al. 2021

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Hydrothermal liquefaction is one of the common thermochemical conversion methods adapted to convert high-water content biomass feedstocks to biofuels and many other valuable industrial chemicals. The hydrothermal process is broadly classified into carbonization, liquefaction, and gasification with hydrothermal liquefaction conducted in the intermediate temperature range of 250–374 °C and pressure of 4–25 MPa. Due to the ease of adaptability, there has been considerable research into the process on using various types of biomass feedstocks. Over the years, various solvents and co-solvents have been used as mediums of conversion, to promote easy decomposition of the lignocellulosic components in biomass. The product separation process, to obtain the final products, typically involves multiple extraction and evaporation steps, which greatly depend on the type of extractive solvents and process parameters. In general, the main aim of the hydrothermal process is to produce a primary product, such as bio-oil, biochar, gases, or industrial chemicals, such as adhesives, benzene, toluene, and xylene. All of the secondary products become part of the side streams. The optimum process parameters are obtained to improve the yield and quality of the primary products. A great deal of the process depends on understanding the underlined reaction chemistry during the process. Therefore, this article reviews the major works conducted in the field of hydrothermal liquefaction in order to understand the mechanism of lignocellulosic conversion, describing the concept of a batch and a continuous process with the most recent state-of-art technologies in the field. Further, the article provides detailed insight into the effects of various process parameters, co-solvents, and extraction solvents, and their effects on the products’ yield and quality. It also provides information about possible applications of products obtained through liquefaction. Lastly, it addresses gaps in research and provides suggestions for future studies.

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Mechanism of the Fe-Assisted Hydrothermal Liquefaction of Lignocellulosic Biomass

Cited by 36 publications

References 42 publications

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

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

Recent Advances in Hydroliquefaction of Biomass for Bio-oil Production Using In Situ Hydrogen Donors

A Review of Hydrothermal Liquefaction of Biomass for Biofuels Production with a Special Focus on the Effect of Process Parameters, Co-Solvents, and Extraction Solvents

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