Biofuels Bioproducts & Biorefining-Biofpr最新文献

This review critically examines recent advances in the use of rice straw and barley straw as lignocellulosic feedstocks for second-generation biofuel production. A comprehensive analysis of their chemical composition, including cellulose, hemicellulose, lignin, and ash content, reveals how these intrinsic properties affect the efficiency of conversion to bioethanol, biogas, and bio-oil. Pretreatment methods including steam explosion, ionic liquids, alkaline treatments, and microwave-assisted ammoniation are evaluated for their effects on sugar release, microbial digestion, and thermal degradation. Comparative analysis highlights the differing processing needs and biofuel yields of rice straw and barley straw, with discussion of catalytic systems, reactor configurations, and integration strategies. Logistical challenges in residue collection, storage, and transport are explored, along with emerging solutions such as decentralized biorefineries and digital optimization through Industry 4.0 technologies. The review concludes that the strategic integration of biochemical and thermochemical pathways, tailored to regional biomass characteristics and supported by policy and infrastructure, is essential to unlock the full potential of rice and barley straw as sustainable bioenergy resources.

Energy cane has emerged as a promising feedstock for biorefineries due to its high fiber yield and potential for diversified bioproducts. This study evaluated the fiber composition of 190 energy cane genotypes and assessed their theoretical potential for producing second-generation (2G) ethanol, polyethylene, and xylitol. The results showed moderate variability in cellulose, hemicellulose, and lignin contents, which influenced the estimated yields of the selected bioproducts. Genotypes such as G192 and G53 demonstrated particularly high potential, with total 2G ethanol yields exceeding 500 L per metric Mg of fiber and significant outputs of polyethylene and xylitol. Compared with conventional biomass sources reported in the literature, such as sugarcane, eucalyptus, and sorghum, energy cane presented superior energy recovery per hectare. However, challenges remain for large-scale adoption, including lower sugar content, increased logistics costs, and the high investment required for processing technologies. Despite these barriers, the findings underscore the strategic role of energy cane in future biorefinery systems and provide valuable data to support genotype selection and industrial planning.

This study examines how renewable energy indicators such as biofuel prices, biofuel integration, electrification, and carbon allowance prices relate to refined fuel production in Portugal’s refining sector. This is set against the backdrop of the sector’s decarbonization efforts and the economic pressures to meet European Union climate targets. The research employs a vector error correction model using monthly data from January 2019 to June 2024 to analyze both short- and long-term dynamics. The results show significant volatility in fossil fuel production associated with fluctuations in biofuel prices and carbon allowances. Additionally, biomass production exhibits an initially negative relationship with refining, while biofuel incorporation shows a slightly positive initial association. In both cases, the relationship with refining output becomes unstable over time. Contrary to expectations, the initial increase in energy consumption for electric vehicle charging appears to stimulate refined fuel production, although this effect weakens over time throughout the period analyzed. As a robustness check, the results were validated using an autoregressive distributed lag error correction model, which confirmed the short-term adjustment patterns and provided additional insight into the long-term dynamics. The findings emphasize the need for a gradual adaptation strategy that invests in co-processing technologies and flexible operations to transition from fossil-based products to renewable alternatives. Policymakers should ensure regulatory stability to boost the competitiveness of biofuels and promote a more sustainable refining sector.

This review evaluates miscanthus, a high-yielding perennial grass with substantial carbon sequestration potential, as a feedstock for producing solid carbonaceous products. Miscanthus was found to be a suitable feedstock, comparable to woody and grassy phytomass. The most sustainable products, in both economic and technological terms, were torrefied miscanthus (solid fuel), slow-pyrolysis biochar (solid fuel and soil amendment), and activated carbon (AC) produced by H₃PO₄ activation (functionalized adsorbents for organic and inorganic pollutant removal). Industrial-scale cost estimates indicate production costs of ~50–70 € t⁻¹ for torrefied miscanthus, ~130–150 € t⁻¹ for biochar, and ~2000 € t⁻¹ for AC, which is competitive with conventional phytomass-derived equivalents. Future research should focus on optimizing miscanthus cultivation to enhance product yield and quality, on developing valorization pathways for higher value products (such as functionalized biochar and humic acids), and on improving activation techniques. For chemical activation, increasing phosphoric acid efficiency and exploring alternative agents is crucial, and physical activation should aim to produce AC with porosity comparable to traditional feedstocks. These advancements are essential for improving the economic viability and environmental sustainability of miscanthus-based biorefineries.

Biochar, a carbonaceous by-product of pyrolytic biomass, is currently attracting worldwide attention with its immense scope to transform sustainable agriculture. This review elaborates on the effect of biochar on soil physicochemical and biological characteristics, crop yields, and tolerance to environmental stresses. Biochar enhances soil porosity, water holding capacity, nutrient supply, and microbial activity and thus enhances plant growth and yields. Its performance is very much a function of feedstock quality, pyrolysis parameters, and application rates, with low-temperature biochar favoring nutrient supplementation and high-temperature biochar favoring carbon sequestration over the long term. Biochar also decreases the bioavailability of heavy metals and alleviates plant stress owing to drought, salinity, and pathogen attack. The variability in outcomes for different soils and potential for contaminants require standards-based production and site-specific application protocols. This review identifies biochar’s diverse advantages and creates a blueprint for its safe and efficient application as a long-term amendment in multiple agricultural systems.

The growing population and standard of living on the planet have led to an increase in production and consumption waste. Involvement of the waste in the process of energy generation facilitates addressing recycling problem, promotes sustainable energy production, lowers the reliance on fossil fuels, and reduces emissions of harmful substances into the atmosphere. The paper focuses on three types of biomass – wood waste, agricultural products (dedicated energy crops and their waste forms), and municipal solid waste. The energy potential of these biomass types in the five BRICS countries accounts for 40.3% of the global total. The greatest energy potential of the resources is observed in China (6.9 EJ per year). In India, the biomass potential is estimated at 6.1 EJ per year, followed by Brazil at 5.9 EJ per year, Russia at 1.0 EJ per year, and South Africa at 0.3 EJ per year. In the majority of the countries analyzed, agricultural products account for the largest share of biomass at 53.9%, with municipal waste contributing 27.2% and woody waste standing at 18.9%. This supply of biomass is sufficient to cover an average of 8.4% of final energy consumption in the BRICS countries.

Buffering capacity (BC) is essential for maintaining pH stability during fermentation, directly impacting yeast performance, aroma formation, and final beverage quality. This study evaluated the BC and pH dynamics of sugarcane juice from 10 genotypes before and after fermentation to identify traits associated with juice stability. Juices were fermented with Saccharomyces cerevisiae (3 × 10⁷ cells mL⁻¹), and the BC was assessed by titrating 20 mL samples of non-fermented (NFSCJ) and fermented sugarcane juice (FSCJ) with 1 m HCl, recording pH changes after each addition. The BC was calculated based on hydrogen ion concentration shifts. Significant variation was observed among genotypes: RB992506 (NFSCJ) and RB002754 (FSCJ) showed the highest BC values, while RB962962 (NFSCJ) and RB1443 (FSCJ) provided the lowest BC values. These occured owing to the presence of nitrogenous compounds, including amino acids, peptides and polypeptides. The findings underscore the importance of genotype selection in optimizing fermentation performance and ensuring consistent quality in sugarcane-based fermented products.

The conversion of carbon dioxide (CO₂) into high value products is a key strategy for emission mitigation and sustainable process development. This study successfully demonstrates a continuous flow system for the efficient carboxylation of styrene oxide using CO₂ and CuO/Al₂O₃ as a heterogeneous catalyst. Various operating parameters, including temperature, pressure, and reagent flow rate, were optimized to maximize conversion and selectivity. The results showed that the optimal reaction conditions of 120 °C, a CO₂ flow rate of 15–18 mL min⁻¹, and a styrene oxide feed of 0.1 mL min⁻¹ achieved conversions above 99% with 100% selectivity in residence times of 30–45 min. Compared with batch methods, the continuous flow process demonstrated superior efficiency, offering a more sustainable alternative for cyclic carbonate synthesis. This approach presents significant potential for CO₂ fixation and green chemistry applications.

The use of new intensification technologies for continuous biodiesel production will facilitate the development of this renewable fuel. The aim of this research is to develop an oscillatory–liquid phase plasma reactor for the production of biodiesel from sunflower oil. Experimental tests were conducted using the independent variables of methanol-to-oil molar ratio, catalyst level, applied voltage, and flow rate (Q). Response surface methodology was used to analyze and optimize the experimental results. The results showed that the optimal conversion efficiency of 91.31% can be continuously achieved at the methanol to oil molar ratio (7.24), catalyst level (0.85 wt%), applied voltage (19.33 kV), and Q (3.11 mL s⁻¹). The produced biodiesel complies with EN 14214 standards, making it a suitable alternative to diesel fuel. Considering the high efficiency, continuous production, reduced reagent consumption, and low power consumption, this new method can be introduced as sustainable solution in the biodiesel production industry.

This study comprehensively investigates the efficiency of native mixed algae systems in removing nitrate and phosphate from synthetic wastewater. Mixed algae do not require sterilization of the culture medium, and the process operation is more accessible, providing better industrial applicability. The effects of three key variables temperature (20, 25, and 30 °C), pH (6–8), and nitrogen-to-phosphorus (N/P) ratio (1, 5, 10, and 15) on algal growth rate and pollutant removal efficiency were evaluated using both experimental observations and kinetic modeling. The findings indicated that a pH level of 7 and a temperature of 25 °C provide the most favorable conditions for algal proliferation and nutrient removal. Both experimental data and kinetic analysis consistently demonstrated that the maximum growth rate (μ_max = 0.32 day⁻¹) and nutrient removal efficiency for nitrate (95.6 mg L⁻¹ day⁻¹) and phosphate (1.56 mg L⁻¹ day⁻¹) were achieved at an N/P ratio of 10. Higher ratios, such as 15, were also evaluated under the same optimized conditions, but both growth (μ_max = 0.24 day⁻¹) and nutrient removal for nitrate (86.2 mg L⁻¹ day⁻¹) and phosphate (1.22 mg L⁻¹ day⁻¹) were lower than at N/P = 10. These results confirm that the N/P ratio is the key factor controlling algal growth and nutrient uptake, rather than the biomass concentration alone. Analysis of variance further confirmed that both N/P ratio and temperature significantly influenced nitrate and phosphate removal (P < 0.05), while pH variations in the range of 6–8 had no significant effect.