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Over 30% of the world's land area is covered by forests. Approximately 761 million m3 of wood is harvested annually in Europe (2017). The aim of the paper is to assess the amount of wood (biomass) produced in Europe per year, as it determines the amount of carbon dioxide released from wood because of combustion for heating and energy purposes. The circular bioeconomy was applied as the theoretical framework for this study. The study employs official statistics on material flows and also uses a technology assessment, which allows for more precise estimations. It can be estimated that 110 million tons of harvested woody biomass are converted into energy every year. This constitutes nearly 69% of processed wood, with burned wood treated as zero-emission. From the analysis of the compiled results, it can be concluded that, in Europe, more than 50% of the mass of raw wood material harvested per year is used for energy in the first stage of processing by manufacturing industries. These processes produce products that become the raw material for further processing, as a result of which, further amounts of wood biomass are used for energy purposes. [ABSTRACT FROM AUTHOR]

The fractional and chemical composition of bio-oil and its gasoline fraction, obtained by hydrothermal liquefaction of Arthrospira platensis biomass, was studied. The bio-oil yield was 34.6%, the heat of combustion of bio-oil was 33.4 MJ kg-1, and the gasoline fraction yield was 28.8%. The content of carbon and hydrogen in the gasoline fraction of the bio-oil is appreciably higher than in the initial bio-oil, and the calorific value of the gasoline fraction is 3.87 MJ kg-1 higher than that of the initial bio-oil. With respect to the carbon and hydrogen content, the gasoline fraction of the bio-oil is close to motor fuels, differing from them in the higher content of nitrogen, oxygen, and sulfur. Fractional distillation of bio-oil decreases the content of high-molecular-mass condensed compounds in the product. [ABSTRACT FROM AUTHOR]

In this study, black alder (Alnus glutinosa L.) wood samples were subjected to supercritical fluid extraction (SFE) using acetone, methanol, and water as solvent. The highest yield (62.4%) of SFE was obtained from black alder with water solvent at 678 K. The supercritical fluid extracts were fractionated into water soluble, acetone soluble, phenolic, fatty acid, polar, and nonpolar fractions. The lowest and highest yields of phenolic fractions from the supercritical water extraction runs were 5.3% and 15.4%. The lowest and highest yields of polar fractions from the supercritical water extraction runs were 14.6% and 16.7%. Increases of higher heating values (HHVs) in the supercritical fluid extracts are range from 48.1% to 71.4%, from 41.7% to 67.2%, and from 34.4% to 61.9% for acetone, methanol, and water, respectively. Carbon and hydrogen contents in supercritical fluid extracts are higher than those of in the original black alder sample. [ABSTRACT FROM PUBLISHER]

Hydrothermal liquefaction (HTL) uses heat and pressure to liquefy the organic matter in biomass/waste feedstocks to produce biocrude. When hydrotreated the biocrude is converted into transportation fuels including sustainable aviation fuel (SAF). Further, by liquifying the organic matter in wet wastes such as sewage sludge, manure, and food waste, HTL can prevent landfilling or other disposal methods such as anerobic digestion, or incineration. A significant roadblock to the development of a new route for SAF is the strict approval process, and the large volumes required (>400 L) for testing. Tier α and β testing can predict some of the properties required for ASTM testing with <400 mL samples. The current study is the first to investigate the potential for utilizing wet-waste HTL biocrude (WWHTLB) as an SAF feedstock. Herein, several WWHTLB samples were produced from food waste, sewage sludge, and fats, oils, and grease, and subsequently hydrotreated and distilled to produce SAF samples. The fuels (both undistilled and distilled samples) were analyzed via elemental and 2D-GC-MS. Herein, we report the Tier α and β analysis of an SAF sample derived originally from a WWHTLB. The results of this work indicate that the upgraded WWHTLB material exhibits key fuel properties, including carbon number distribution, distillation profile, surface tension, density, viscosity, heat of combustion, and flash point, which all fall within the required range for aviation fuel. WWHTLB has therefore been shown to be a promising candidate feedstock for the production of SAF. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoS x catalyst with S vacancy was in-situ formed for the co-HDO reaction. • DFT calculations reveal the easy formation of H* from H 2 on MoS x plane. • MoS x catalyst helps to produce more liquid and gaseous products during co-HDO reaction. • MoS x catalyst facilitates the accumulation of more than 50 % oxygen into polar liquid. • After co-HDO reaction, bio-fuels exhibited high combustion heat of ∼47 MJ kg−1. Obtaining bio-fuels (including gas and bio-oil) with high energy density remains a huge challenge due to their high oxygen content. Here we report a novel MoS x catalyst in-situ formed in a pilot-scale plant can effectively promote the co-hydrodeoxygenation (co-HDO) reaction of poplar wood sawdust and vacuum gas oil with H 2. Because of the sulfur vacancies on MoS x , the co-HDO reaction is facilitated along with a significant accumulation of oxygen (over 50.0 wt.%) into an oil-insoluble polar-liquid, leading to a high combustion heat of ∼47 MJ kg−1 of the bio-fuels. Besides, the presence of MoS x also affords a lowered molecular weight of the deoxidized bio-fuels. Based on the underlying conversion mechanisms, the co-HDO reaction can be enhanced in the presence of MoS x catalyst by promoting oxygen transfer towards the polar-liquid during the co-HDO process. [ABSTRACT FROM AUTHOR]

• Bio-oil from liquefaction of microalgae was upgraded by emulsification. • A comparison on fuel properties between bio-oil and emulsion fuel was provided. • Storage stability of emulsion fuel was firstly explored by boiling point analysis. • A possible stability mechanism was proposed based on storage stability analysis. This work studied the hydrothermal liquefaction of Chlorella pyrenoidosa and effect of emulsification on upgrading the bio-oil. The fuel properties and storage stability characteristics of emulsion fuels were explored. The combustion characteristic analysis showed that the ignition temperatures of emulsion fuels (139.6–151.3 °C) were lower than that of bio-oil (176.9 °C). Besides, emulsion fuels had higher comprehensive combustion indexes (7.24–14.08 × 10−6 × min−2 × C−3) than bio-oil (1.51 × 10−6 × min−2 × C−3), indicating that emulsion fuels had better combustion performance. The kinetic analysis showed that emulsification could effectively reduce the activation energy, resulting in less energy input for combustion. Based on chemical composition evolution during the storage process, a possible stability mechanism was proposed. The storage stability analysis indicated that the diesel-solvable fractions in bio-oil had better stability. Overall, this work provides a feasible way for bio-oil upgrading through emulsification. In addition, a better understanding of the stability property of emulsion fuel was provided. [ABSTRACT FROM AUTHOR]