Biomass & Bioenergy最新文献

Hydrogen-supplied liquefaction technology is considered to be one of the most essential thermal treatment strategies for improving the quality of bio-oil. This study employed wood chips as feedstock, inert alkanes as dispersing solvent, and tetraline as hydrogen donor. The yields of bio-oil rose substantially from 45.2% to 69.2% and 68.3% with CaO and 8% NiO/γ-Al₂O₃ catalysts, respectively, at 310 °C for 30 min with a ratio of wood chips to n-heptane of 1:8 g ml⁻¹. The reaction mechanism was examined using microcrystalline cellulose and lignin as model compounds. Tetralin offered the active hydrogen, while the strong alkalinity of CaO brought about high-temperature fragmentation of cellulose to produce small-molecule ethers, aldehydes, and ketones. These species would eventually transform into alcohols through engaging with the active hydrogen. The introduction of NiO/γ-Al₂O₃ promoted the ring-forming reaction of cellulose-derived fragments, resulting in an increase of furan content (up to 29.97%). This phenomenon suggested that the varied catalysts exerted a remarkable impact on the hydrogen-supplied liquefaction of cellulose. The catalytic effect on lignin was evident in the breakage of the C–O bond in the side chain of phenol, leading to the generation of an impressive amount of phenolics. In light of changes in the generated products and calculation of the theoretical bond energies, the bond-breaking approaches and potential reaction pathways of biomass impacted by different catalysts were proposed, providing a theoretical foundation for the development and application of biomass energy.

Biochar is made from organic materials and plays an important role in greenhouse gas removal (GGR) and achieving net-zero target. However, economic feasibility has become a primary constraint hindering the large-scale production of biochar. Existing research lacks consideration of practical factors such as feedstock supply, pricing, and factory scale, and cannot accurately evaluate the greenhouse gas (GHG) reduction effect and corresponding costs at scale. We develop a space-based environmental economic model to quantify the impact of feedstock supply and plant strategies on costs and benefits. The results show that biochar production in the East of England and the East Midlands could achieve significant net GHG reduction and GGR benefits. Environmental benefits are not related to factory strategy but are positively correlated with feedstock supply strategy. Biochar production imposes additional financial burdens that are affected by feedstock supply and factory strategy. The main factors influencing biochar scalability are the quantity and pricing of feedstock and the price of byproducts. Spatial heterogeneity significantly influences the unit cost of GGR benefits. Compared to previous studies, spatial analysis provides a more detailed understanding of the costs associated with scaling up biochar production and the spatial distribution of production costs. This has crucial implications for biochar promotion and the implementation of effective policies.

Glycerol to syngas conversion was investigated with the effect of various binary oxides such as M₂O₃.Al₂O₃ (M = La, Mn, and Cr), prepared by simple solid state route, along with impregnation method of 10% wt Ni. BET, XRD, TPR, TPO, TPD, and SEM techniques were applied in this study for the evaluation of the physicochemical characteristics of materials. Amid the examined catalysts, 10Ni/La₂O₃.Al₂O₃ sample caused an increase in glycerol conversion to 54.61% at 750 °C and GHSV = 54000 mL/g.h and led to improved long stability of the 10Ni/Al₂O₃ due to the presence of strong basic sites. In the next phase of research, different xLa₂O₃.yAl₂O₃ weight ratios were synthesized to evaluate the optimum La content. Weight ratio equal to one selected to achieve the best performance in terms of catalytic activity and durability. Reaction conditions’ investigation i.e. GHSV and CGR proved that were mainly effective parameters whose increasing trend leads to a decrease in glycerol conversion.

As a crucial energy carrier, waste cooking oil poses a significant threat to land and water resources. Furthermore, there is a risk of its reintroduction into the restaurant system, posing a direct threat to public health. Hence, converting waste cooking oil into clean energy has emerged as a pressing concern. This study compares the CO₂ emissions and economic benefits of two pathways applied to automotive energy consumption——the waste cooking oil produced biodiesel pathway and the waste cooking oil mixed with coal for power generation pathway. The results show that for both diesel and electric versions of the same brand of vehicles, the CO₂ emission of an electric vehicle using waste cooking oil mixed coal produced electricity is 0.181 kg/km, which is a 26.12% reduction compared to a diesel vehicle using waste cooking oil converted to biodiesel. Consumers appreciate the low price of electricity. However, for producers, the waste cooking oil produced biodiesel pathway demonstrates superior economic benefits. At the current market price, converting waste cooking oil into biodiesel will result in a net gain of 112.89 billion Yuan for the producer, whereas the waste cooking oil mixed with coal for power generation pathway will result in only 2.08 billion Yuan in net gain. This disparity is primarily attributed to the lower electricity prices for electric vehicles. To encourage the widespread adoption of waste cooking oil energization technologies, Chinese government can raise electricity prices for electric vehicles to a minimum of 1.599 Yuan/kW·h, ensuring equal net gains in both pathways.

Hydrothermal carbonization (HTC) is a promising technique for the conversion of lignocellulosic biomass, such as two-phase olive mill waste (TPOMW). However, the resulting generated aqueous phase (AP) rich in organic compounds is harmful if directly discharged in the environment. In this work, the use of recycled aqueous phase from the HTC process of TPOMW is evaluated as a reactive medium. The evolution of products yields, quality, morphology chemical structure, and composition with AP recycling runs are investigated by different analytical methods (Nuclear Magnetic Spectroscopy ¹H and solid state ¹³C, Scanning Electron Microscopy, Elemental analysis, Proximate analysis, Fourier Infrared Transform spectroscopy, Total organic carbon, and total nitrogen). The results revealed significant improvement in the hydrochar yield and energy yield that increase 47.4 wt% to 53.0 wt% and 72.8%–81.3%, respectively. The increase in the number of recycling experiments promotes the lignin condensation as well as the polymerization of AP intermediates into microspheres. These phenomena lead to the increase in hydrochar yield as well as the modification of its micro-surface into a smooth porous surface through the recycling runs. Additionally, FT-IR and the solid state ¹³C NMR analysis demonstrated that AP recycling has no noticeable effect on the chemical structure of the produced hydrochars. Further analysis of the AP demonstrated that the total organic carbon and total nitrogen increase significantly after the first recycling run from 17.3 to 26.5 g/L and 0.4–0.6 g/L, respectively. The ¹H NMR analysis revealed that AP is mainly formed by aliphatic and aromatic compounds.

The pulp and paper industry use biomass residues, such as paper sludge and bark as fuel to provide energy for their plants. However, issues such as high-water content or low heating value limit the amount of energy that can be utilized. Processes to improve heat generation include biomass densification, which facilitates transportation and handling and can increase energy yield. However, the technical feasibility of briquetting is a function of the feedstock and preprocessing. This study introduces a novel approach to briquette production from biomass residues by utilizing wet biomass with water as a natural binder, contrasting with conventional methods that require forced drying and/or the addition of binders. The objective of this research was to investigate the impact of briquetting both unprocessed biomass and post-hydrothermal carbonization. The study focused on manufacturing briquettes derived from different sources, including bark (Balsam fir), paper sludge, and hydrochar of paper sludge. The feedstock was characterized for ash content and higher heating value. Biomass particle size (range), moisture content (range), process temperature (range), process pressure (range), and process residence time (range) were varied in briquetting experiments to determine conditions to produce high-quality briquettes with minimal energy input. Moisture content as high a 50 wt% in feedstock produced technically feasible briquettes, with appropriate physical-mechanical properties (durability, volumetric expansion and apparent density), and energetic potential (calorific value). The addition of heat (pressing temperature of 150 °C) during the pressing process resulted in briquettes with enhanced physical-mechanical, and energetic properties, surpassing those produced at room temperature. Further tests with additional steps in the production process are required to meet commercialization standards in Canada, but the treatments conducted in this study effectively improved the energy potential of biomass for internal industrial energy gains.

Biochar (BC) is a carbonaceous material obtained from the thermal decomposition of organic matter under limited oxygen supply that plays an attractive role in waste management. In this study, biochar was prepared from sugarcane bagasse, using pyrolysis temperatures from 300 to 700 °C, and chemically activated with HNO₃. Structural characterizations showed that degradation increased as pyrolysis temperature increased. Furthermore, a higher number of functional groups were observed for the materials produced under the lowest temperatures. Chemical activation resulted in oxidation and nitration of carbonaceous structure, increasing the number of functional groups on the materials. All materials were evaluated for the construction of electrochemical sensors towards Cu²⁺ ions voltammetric determination. The material produced at 400 °C pyrolysis temperature and activated (BCA400) provided the most intense response, which can be related to the presence of one of the highest numbers of surface groups, such as oxygen groups, on it. A method for Cu²⁺ determination was successfully developed based on differential pulse adsorptive stripping voltammetry (DPAdSV). A linear dynamic range (LDR) from 1.0 to 15.0 μmol L⁻¹ was achieved, with limit of detection (LOD) of 0.36 μmol L⁻¹, and limit of quantification (LOQ) of 1.09 μmol L⁻¹. The method was also adequate in terms of accuracy and precision, as well as selective against most cationic species commonly found in tap water. The analyte was determined in tap water samples, in natura and spiked with the maximum concentration allowed by Brazilian legislation, and successful recovery values were obtained. Therefore, biochar from sugarcane bagasse, an environmentally-friendly material, was successfully used to construct an electrochemical sensor and determining an environmental and health interest analyte.

Co-combustion of biomass and sludge is a promising method for waste treatment and power generation. In this study, additives such as ammonium dihydrogen phosphate (ADP), calcium oxide (CaO), attapulgite (AT), and their combinations were added into the co-pelletization of semi-dry sludge (with approximately 50% water content) and extraction residue from vegetable oil processing. The objective of the studies was to examine the pelletization behavior, reduce off-gas emissions during the combustion, and investigate the mechanisms influenced by these additives through the thermogravimetric analysis and the tube furnace combustion experiment. The results of the analysis of variance (ANOVA) indicated an increase in pellet density due to the addition of additives. During the combustion, the addition of AT and compound additives generated more complex compounds with high melting temperatures, thereby mitigating the high slagging tendency. Meanwhile, additives facilitated the conversion of ultrafine particles (PM_0.1) to fine particles, leading to a reduction in PM_0.1 emissions by 15.60–42.40%. The additives exhibited efficacy in reducing SO₂ emissions, with a reduction range of 5.00–23.20%. However, the addition of ADP additives resulted in a 12.00% increase in NO emissions. Consequently, adding additives to pellets could address the slagging issue and reduce the emission of air pollutants during combustion.

Biochar can be prepared from biomass through pyrolysis in a low-oxygen or anaerobic environment. The characteristics of biochar are influenced by raw materials and the specific preparation process employed. To enhance the efficacy of biochar, various modification methods can be applied. These primarily include chemical modification, physical modification, and biological modification. This paper conducts a literature review covering the period from 2018 to 2023, focusing on biochar preparation, modification methods, and environmental applications. It is a comprehensive overview of the processes involved in preparing biochar, analyzes its characteristics, and explores various modification techniques. Additionally, the paper discusses the diverse and highly efficient application of biochar in environmental remediation, with a particular emphasis on its use in soil, water, and the atmosphere. While biochar holds significant potential for environmental remediation, a thorough understanding of its mechanism in environmental applications is still lacking. Further in-depth studies are required to elucidate the complex roles biochar plays in various environmental contexts.

Manganese oxide biochar composites (MnOx-BCs) are at the frontier of materials development for current environmental and engineering challenges in contaminant sorption and degradation, capacitive deionisation, as well as supercapacitor research. However, the parameter space for optimisation of such composites is vast, spanning from the choice of feedstocks and synthesis procedure to post-processing. This study uses a systematic literature review methodology to provide a comprehensive view into the synthesis methods and applications of MnOx-BCs. The focus is on the manganese phase oxidation states, which are often decisive for a material’s properties but not directly comparable with the (well-explored) synthesis of pure MnOx due to the chemical variability of biochars. The relationships between synthesis method, manganese phase, crystallinity and morphology, as well as biochar type are characterised. We argue that careful selection of the desired manganese phase and oxidation state are as important as careful consideration of the bulk chemistry and microstructure of the biochar phase. Much evidence already exists for fine-tuning these combinations, but there is still a clear research gap in systematically studying the biochar impact on the final MnOx phase.