BioEnergy Research最新文献

The integration of automation, artificial intelligence (AI), and machine learning (ML) is revolutionizing the field of biomass transformation by enabling smarter, more efficient, and scalable processes. AI/ML have shown significant promise in enhancing processes such as biofuel production, anaerobic digestion, and waste-to-energy conversion by enabling predictive analytics, process control, and real-time monitoring. For instance, ML algorithms can predict optimal fermentation conditions for bioethanol production, while deep learning models can enhance enzyme selection for the breakdown of lignocellulosic biomass. Intelligent decision support systems (IDSS) are being applied to improve process efficiency in biogas plants by analyzing large datasets from sensor networks. Despite these advancements, critical challenges remain, including the need for laboratory automation, robust data infrastructure, a skilled workforce, and broader technology adoption. This review uniquely consolidates and analyzes the integration of AI/ML across a wide spectrum of biomass transformation processes, rather than focusing on isolated applications as seen in previous studies. This review presents a comprehensive overview of current developments, identifies existing limitations, and outlines future directions for researchers and practitioners aiming to drive innovation in this interdisciplinary field.

Small sewage treatment plants (STPs) in developing regions often flare the biogas produced in their upflow anaerobic sludge blanket (UASB) reactors, giving away a cost-effective energy source. This study tests whether on-site biogas-to-energy can pay for itself in approximately 2 years, even in plants treating less than 30 l s⁻¹. A small-scale STP in Angra dos Reis, Brazil (25 L/s), was studied, with an average biogas flow of 9.7 m³/h; electricity generation was modeled for an engine generator unit with an efficiency of 30%. The techno-economic results show that the actual system would generate 125 MWh/year at a levelized cost of 0.017–0.023 USD/kWh, covering 47% of the plant’s electricity demand. At a discount rate of 8%, the net present value was + 9.3 k US$, and the simple payback period was 2 years for the initial investment. Additionally, extrapolating the results to account for future expansion of the sewage treatment plant based on the total population in the region served by the system reveals even more promising results, with a suggested payback period of 1 year and 1 month of operation, covering approximately 57% of electricity demand. Scaling this retrofit to the approximately 18,000 comparable UASB-based STPs worldwide at low capital cost could reduce electricity bills by approximately 40% and avoid ~ 450 tons of CO₂-eq. per plant per year through methane capture and displacement of electricity from the grid. These results confirm that decentralized biogas power generation on a small scale is not only technically feasible, but also financially attractive and ecologically beneficial for operators of sewage and wastewater treatment plants and municipalities.

This research explored hydrothermal carbonization to enhance digestate from lignocellulosic biogas power plants as a soil amendment for low-carbon agriculture. Hydrochar was produced from real digestate via hydrothermal carbonization at 225–265 °C, hydrothermal carbonization at 265 °C demonstrating optimal properties for agricultural use. Key benefits include enhanced phosphorus retention, controlled-release nutrient behavior as indicated by Chlorella vulgaris cultivation in its water-soluble fraction, and safe application as a soil amendment, with heavy metal concentrations within regulatory limits and absent in the water-soluble fraction. Based on theoretical calculations, labile carbon—represented by the water-soluble organic carbon fraction in hydrochar—was reduced 15-fold at 265 °C compared to the digestate. This reduction could decrease greenhouse gas emissions from 441 to 29 tons CO₂-equivalent annually in a 1 MW biogas plant scenario, while sequestering 766 tons of carbon in cropland soils. Additionally, theoretical calculations suggest co-digestion with hydrothermal wastewater could enhance nutrient recovery and methane production, contributing to low-carbon emissions. These findings underscore hydrothermal carbonization’s potential for sustainable biogas power plant, agriculture, and climate change mitigation.

Volatile fatty acid accumulation may cause inhibition, or complete cessation of methanogenesis, which was undesirable for large-scale anaerobic digestion (AD) engineering. In this study, it was unexpectedly observed that methanogenesis gradually resumed after a long period of time when gas production had stopped due to acid inhibition in maize straw solid-state (SS)-AD. The results showed SS-AD achieved the cumulative methane production of 9.32 mL/gVS and maintained the acetic acid degradation rate at 70.8%–88.8% within 8 days of methanogenesis recovery. 16S rRNA amplicon sequencing and metagenomic analysis revealed that Thermoclostridium, Defluviitalea, and Hydrogenispora were the key bacteria resisting extreme acidic stress, while Methanosarcina mazei, Methanoculleus thermophilus, and Methanosarcina thermophila were the key archaea promoting methanogenesis recovery. Microorganisms survived under extreme acidic stress mainly by lysine decarboxylation and biosynthesis of cell membranes/walls and flagella. Meanwhile, enhanced tryptophan synthesis and metabolism accelerated carbon supply to TCA cycle, promoting the growth and reproduction of microorganisms under extreme acidic stress. Moreover, the genetic information processing ability and CRISPR-Cas system were enhanced in M. mazei and M. thermophila, which favored their survival and growth in SS-AD. M. thermophilus mainly contributed to the methanogenesis by CO₂ reduction. This study helps in developing SS-AD methodology for overcoming extreme acidic stress.

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The high cost of biomass feedstock hinders the growth of the cellulosic ethanol industry, especially in regions like China where biomass is extensively dispersed. To tackle this issue, we devised a biomass supply chain model encompassing collection, pretreatment, storage, and transportation phases. We examined the effects of various collection and pretreatment method combinations on supply-chain costs and CO₂ emissions. The model’s validity was confirmed using Heilongjiang and Zhejiang as representatives of northern and southern regions. Mechanized collection with shredding-baling proved to be the most economical, costing 226.6 y/t in Heilongjiang and 217.7 y/t in Zhejiang within a 60 km collection radius. For CO₂ emissions, mechanized collection with kneading emerged as the optimal choice. With governmental subsidies, mechanized collection with kneading became the preferred option, considering both cost and CO₂ emissions. By incorporating agricultural cooperatives, costs were further reduced by up to 70 y/t in Heilongjiang and 65 y/t in Zhejiang. This model facilitates the cost-effective collection of straw for ethanol production in biomass-scattered China. Biomass decentralization combining collection and pretreatment methods is key to achieving site-specific biomass supply. Furthermore, the model can be adapted for acquiring biomass feedstock in other sectors and offers insights for biomass procurement in diverse regions.

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Major challenges in using lignocellulosic residues as biogas substrates arise from their high diversity and their typically low nitrogen content, which may not provide sufficient nitrogen for the microorganisms. To investigate to what extent such substrates can be used in biogas plants without extensive pre-treatment, this study presents a 300-day continuous co-digestion of lignocellulosic substrates (i.e., sugarcane reed, lemon, and grape leaves) and goat manure while continuously monitoring various process parameters. The results suggest a stable and effective biogas production at a carbon-to-nitrogen ratio (C/N ratio) of 33, with a production of 244 ± 15 mL_N g_VS⁻¹ d⁻¹ biogas. At a higher C/N ratio of 43, the process remained stable, but hindrance was encountered. Process failure occurred at a C/N ratio of 52, where a rapid decline in biogas production was observed, accompanied by an increase in the volatile fatty acids to total alkalinity ratio (from < 0.2 to 0.9), a drop in the pH-value (from > 7 to 5.4), and an increased CO₂-content of the provided biogas (from > 50% to 43%). The compositional analysis of the digestate suggests an insufficient N-supply and a failure of the carbonate and ammonium buffer systems inside the reactor. The experiment also served to validate a previously developed model based on the individual substrates’ degradation kinetics. With a relative root mean square error rRMSE of 8%, the model adequately predicted biogas production within defined limits. However, it could not anticipate process breakdown at high C/N ratios, highlighting a strong limitation.

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Hydrothermal liquefaction (HTL) is a thermal depolymerization of biomass to liquid components in the presence of water at moderate to high temperatures (200–400 °C) and pressures (10–25 MPa). At the threshold of the critical point, the characteristics of water change dramatically, and water behaves like an excellent reacting medium. With the continued expansion of palm oil industries in Malaysia, the abundance of empty fruit bunch (EFB), the largest organic solid waste from palm oil mills, has grown significantly. In the current study, the effects of temperature and dosage of H₂O₂ on hydrothermal liquefaction of EFB were conducted. The maximum yield of bio-oil attained was 25.4 wt% at 275 °C. The presence of an oxidizing agent (H₂O₂) near critical conditions makes the process more effective in the oxidation of lignin. The major components of biocrude oil were cyclopentenone (enone) derivatives and phenol derivatives. The amount of phenol in biocrude oil increased with temperature, reaching a maximum yield of 8.9 wt% when 3 mL of H₂O₂ was added for HTL at 275 °C. The fixed carbon and thermal stability of hydrochar increased when H₂O₂ was introduced during the HTL process. The yield and quality of the products were controlled by the temperature of the HTL process. Meanwhile, the depolymerization of lignin with an oxidant provided phenolic-rich biocrude oil.

According to rising electrical power consumption, attention to bio-transformer oil (BTO) is increasing due to higher environmental and ecological concerns. Thus, this research aimed to identify the appropriate plant-based oils and polyols to prepare BTO synthesized via two-step transesterification involving the transformation of plant-based oils into fatty acid methyl ester (FAME) with methanol and then reacting with polyols to produce polyolesters (POEs). The plant-based oils—palm kernel oil (PK), refined palm oil (RFP), high olein palm oil (HOP), sunflower oil (SF), and soybean oil (SB)—were reacted with various polyols, neopentyl glycol (NPG), trimethylolpropane (TMP), and di-trimethylolpropane (Di-TMP), to produce BTO in forms of neopentyl glycol diester (NPGDE), trimethylolpropane triester (TMPTE), and di-trimethylolpropane tetraester (Di-TMPTTE), respectively. Among these POEs, BTO with TMPTE structure had appropriate properties in terms of dielectric breakdown voltage, kinematic viscosity at 40 °C, and flash point following IEC 62770 specification. However, the pour point and oxidation stability of BTO derived from each FAME (PK-TMPTE: − 7 °C, 22 h/RFP-TMPTE: 19 °C, 35 h/HOP-TMPTE: 17 °C, 30 h/SF-TMPTE: − 14 °C, 3 h and SB-TMPTE: − 10 °C, 4 h, respectively) failed to meet specified standard requirements (≤ − 10 °C and ≥ 13 h). The balance between steric hindrance and unsaturation level generated from the polyols and plant-based oils was crucial in achieving BTO with the desired properties. A 70/30 (w/w) PK-TMPTE/SF-TMPTE blend ratio was observed as an optimal formulation to provide BTO having a low pour point (− 10 °C) and high oxidation stability (15 h), following the standard specification for transformer oil.

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This research focuses on the application of short-term ball milling as a sustainable pretreatment for corn grains, aiming to improve enzymatic hydrolysis and produce glucose syrups. The study evaluated the effects of ball milling on corn properties. The results showed small changes in starch crystallinity and composition but highlighted a significant increase in hydroxyl group availability, as indicated by FTIR. These modifications correlated with a 43% increase in water absorption and a 27% increase in solubility. Enzymatic hydrolysis of samples ball milled for 3 h demonstrated a remarkable improvement, with a starch conversion of 74.15%, representing a 119.5% increase in yield compared to milled corn (control). At the end of the process, a glucose syrup containing 68.7 g/L of glucose plus maltose was obtained. These results highlight the potential of ball milling as a fast, efficient, and environmentally friendly method for corn starch pretreatment before hydrolysis, thus representing a promising and sustainable alternative to traditional starch processing techniques.

The energy use of biogas in Brazil still faces significant technological and logistical challenges, despite the high availability of raw materials. This study evaluates the environmental viability of biogas from cattle manure in a small-scale plant using a well-to-wheels life cycle assessment (LCA) approach. The motivation is to overcome barriers to biogas-to-biomethane conversion in Brazil. Comparing environmental impacts across scenarios helps identify key technological differences, strategies for broader adoption, and ways to integrate small-scale plants as viable producers. The benchmark scenario involves biogas for electricity and heat generation. In contrast, three biomethane upgrade scenarios were proposed, utilizing pressure swing adsorption (PSA), membrane separation (MS), and high-pressure water scrubbing (HPWS), with biomethane used as vehicle fuel. A fourth scenario assessed the direct application of manure as organic fertilizer. Results show that the benchmark performed better than biomethane in acidification (14%) and eutrophication (21%) but was less effective in climate change compared to manure application. Among upgrading technologies, HPWS had the lowest climate change impact (3.16 × 10⁻³ kg CO₂ eq./MJ), MS performed best in acidification (4.33 × 10⁻⁵ kg SO₂ eq./MJ), and PSA had the lowest eutrophication impact (3.61 × 10⁻⁶ kg PO₄ eq./MJ), 53% lower than MS and HPWS. Manure application had the lowest primary energy demand and negative GWP due to avoided synthetic fertilizers, but eutrophication was ten times higher than the benchmark (1.27 × 10⁻³ kg PO₄ eq./MJ), requiring optimized nutrient management. These findings provide insights into upgrading technologies and manure management to support sustainable strategies in Brazil’s energy transition.