BioEnergy Research最新文献

This study reports results from a stochastic techno-economic analysis (TEA) model that assessed the financial feasibility of forest biomass harvest for low-carbon bioenergy feedstocks in the hardwood region of the Northeast United States. It analyzed three 24-year scenarios based on primary data collected from the mixed product harvest with whole tree harvesting systems that primarily produce clean chips, dirty chips, or pulpwood and dirty chips. Using a joint product costing approach, proportional costs of shared processes were allocated to different products on a mass basis. Uncertainty associated with key stochastic variables was incorporated into the model to generate net present values (NPV), benefit–cost ratios (BCR), and minimum selling prices (MSP) via Monte Carlo simulation. The clean chip scenario produced an NPV of $1.36 million and a BCR of 1.03, while the pulpwood scenario’s NPV and BCR ($0.06 million and 1.02) were lower, and the dirty chip scenario generated negative NPV (− $0.02 million) and a BCR of 0.99. The probabilities of achieving positive NPVs for all three scenarios fell between 47 and 56%. The mean MSP for one clean chip scenario was $94.03/dry Mg, while the mean MSPs for two dirty chip scenarios were $74.79/dry Mg and $75.93/dry Mg. NPV results were most sensitive to forest biomass feedstock harvesting production levels, transportation distances, and delivered prices, followed by diesel fuel consumption for in-wood harvest and diesel fuel price.

Considering the difficulty of digesting coffee husk (CH) and water hyacinth (WH) due to the lignin content, the present study investigated the influence of feedstock mixing ratios on the co-digestion performance of CH and WH with food waste (FW) at 38 ± 1 °C and its kinetics. Food waste was considered as co-substrate due to its ease of digestion. Batch experiments were conducted using CH/WH/FW ratios (100:0:0, 0:100:0, 35:35:30, 30:30:40, 25:25:50, 20:20:60, and 0:0:100 w/w) with total solids (TS) content of about 9.5% (w/v). The results indicated that the addition of FW significantly enhanced WH and CH digestion performance, with the maximum biogas yield of 572.60 (pm) 2.30 mL/gVS, best synergistic effect of 1.5, highest biodegradability of 89.22%, and a biodegradation rate of 57.82% obtained at a mix ratio of 25:25:50, which was improved by 179.71% compared to CH mono-digestion. In addition, the organic conversion efficiency of TS and volatile solids reached 69.86 and 81.48%, respectively. Conversely, CH mono-digestion yielded the lowest biogas yield of 204.71 ± 10.74 mL/g VS, highlighting its unfeasibility. The modified logistic equation showed the best fit to the experimental data. The optimum CH/WH/FW ratio of 25:25:50 demonstrated the highest biogas yield and methane content at 66.30 ± 0.76%.

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Paper sludge (PS) from paper mills has a significant potential for bioethanol production. In this study, waste-paper-containing PS is used as the raw material for bioethanol production because the annual waste paper utilization rate has increased globally. Although PS does not require delignification, the antiseptics and deinking agents in waste paper-containing PS inhibit enzymatic reactions such as saccharification and fermentation. Their removal is important, but it has not yet been reported. Using subcritical water pretreatment, the selective decomposition of enzyme inhibitors in PS is examined without the generation of other enzyme inhibitors. The optimum pretreatment conditions are identified as 240 °C, 3.3 MPa, 3 min, and pH 4.5. Glucose was obtained in 71% yield from pretreated 5 wt% PS using cellulase, which is 5.5 times higher than that from unpretreated PS. This is because the reactivity of the pretreated PS increases with increasing surface area of the cellulose fibers, and the cellulase inhibitors are decomposed by subcritical water. Next, semi-simultaneous saccharification and fermentation treatments are performed to produce bioethanol from waste-paper-containing PS. The bioethanol yield based on cellulose after 96 h is 68% for PS pretreated with subcritical water, whereas the bioethanol yield is 6% for unpretreated PS. Therefore, subcritical water pretreatment increases the bioethanol yield by 11 times. The proposed method may enable the use of large amounts of PS as ethanol feedstock in future.

The purification of biogas as a product of anaerobic digestion has gradually become a research focus. In situ hydrogen-assisted biogas purification is an effective way to enhance the reaction rate, but the solubility and mass transfer efficiency of hydrogen are the difficulties that constrain the technology. Thus, four continuous hydrogen injection modes M1: 1 mL/min, M2: 2 mL/min, M3: 5 mL/min, and M4: 10 mL/min and two intermittent hydrogen injection modes A: 4 mL/min ( interval 20 min ) and B: 6 mL/min ( interval 40 min ) were designed to explore the effect of different hydrogen injection modes on in situ biogas upgrading of upflow anaerobic sludge bed (UASB) in the research. The results showed that the methane production showed a trend of increasing first and then decreasing in continuous hydrogenation experiment. The CH₄ production reached its peak at 86.2% in the M2 stage. In the two batch hydrogenation tests, group A showed better hydrogenation effect with a CH₄ production of about 92%, which was 4% higher than that of group B. The hydrogenotrophic methanogens (HMs) in group A archaea community were more effectively enriched, with an abundance of 52.83% of Methanobacterium. The results illustrate that proper hydrogen injection can enhance anaerobic digestion and promote biogas purification, and the effect of short-term intermittent hydrogen injection is more significant.

Anaerobic digestion plays a significant role in obtaining renewable energy through biogas production, reducing greenhouse gas emissions, helping with waste management, and bringing economic and social benefits. This work aims to examine approaches for the treatment and use of cambuci bagasse, identifying typical problems and proposing solutions concerning the application of the technique, control of operational parameters, management in dry regime conditions, optimization of efficiency, and increased productivity, using anaerobic digestion as a fundamental and central technology. The results showed the potential of electric energy and heat that could be generated by burning the biomass in a CHP system. Also, they presented the respective avoided greenhouse gas emissions in situations where biogas is applied to replace conventional heat or electricity sources. The biogas average production ratio was 102.69 m³/ton of cambuci by-product with a methane composition of around 60% in the 24th to 30th days. The experimental data obtained was subjected to calculations that indicate an electric generation of 202.98 kWh/ton of cambuci biomass and heat generation of 913.40 MJ/ton of cambuci biomass. In this theoretical scenario, for each ton of cambuci, it is possible to produce 913.4 MJ of thermal energy and 202.98 kWh of electric energy, considering the biogas burning into a CHP system. In the analysis of types of substrates regarding growth capacity, it was concluded that the substrate with a 30% dilution of the digested end was the one that showed the best growth of the cultivar’s stem, obtaining a CEC of 9.1516 mol/g.

Graphical Abstract

Driven by the urgent need to address climate change, Indonesia, as the world’s largest palm oil producer, faces the challenge of ensuring the sustainability of this industry. This study addresses a critical gap in knowledge by examining the technological advancements in methane capture for bioenergy from palm oil mill effluent (POME), exploring business development applications, and assessing the potential role of methane capture in advancing Indonesia’s Enhanced Nationally Determined Contribution (NDC) targets. Employing both quantitative and qualitative methodologies, the study reveals three key findings. Firstly, a systematic literature review highlights a dearth of research on the social and economic aspects of utilizing biomethane gas, particularly in modeling contexts. Secondly, through case studies, the utilization of methane gas as an energy source is shown to significantly reduce electricity expenditures, diminish reliance on fossil fuels, mitigate carbon emissions, and expand access to clean energy for both companies and households. Thirdly, the scenario of converting POME waste into energy can help to reach the target on carbon emissions, but it depends on the level of waste utilization and capacity factor. By repurposing palm oil industry waste for clean energy production instead of expanding land use, which poses risks to biodiversity, Indonesia can mitigate the challenges of the energy transition and foster a more sustainable future.