Biomass & Bioenergy最新文献

Hydrogenation and hydrogenolysis are the two essential processes which have massive importance on the industrial level to produce value-added chemicals. The hydrogenation or hydrogenolysis of 5-HMF; a key furan compound obtained from the cellulosic biomass led to the formation of 2,5-dimethylfuran (DMF), which is considered as a future biofuel globally because of its high energy density (32.8 MJ/L), water immiscibility and high boiling point (96 °C). The palladium-based catalysts are the most crucial catalysts used in industries for various chemical transformations specifically in hydrogenation reactions. In this review article, we examined the general progress of palladium catalysts on various supports including charcoal, metal organic framework, metal oxides, graphene oxides, acidic supports and critically assessed how the influence of various supports controls the conversion of 5-HMF to DMF. Moreover, the present research's limitations and flaws are also discussed. In the concluding section, we explore the unique catalytic properties necessary for achieving the desired conversion, which aids researchers in developing a suitable catalyst. Overall, palladium catalysis is still in great shape and will require a critical look in the future.

Efficient management of renewable energy sources is crucial for sustainable economic development and reducing carbon footprint. The use of biomass agricultural residues through thermochemical conversion processes, such as gasification, offers a promising solution by producing eco-friendly fuels and chemicals. Biomass properties, type of gasifier and its operating conditions have important roles on the quality and characteristics of gasification products. Entrained flow gasifiers (EFR) and droptube furnaces (DTF) represent popular technologies that can operate at higher temperatures with various feedstock types. They are easy to scale up and commercially available. However, the released syngas may contain impurities like polycyclic aromatic hydrocarbons and soot, impacting the syngas cleaning system and equipment performance. Therefore, the understanding of biomass gasification at a laboratory scale is a preliminary step in evaluating its relevance for industrial applications, for which EFR and DTF can provide extremely useful information. The present manuscript reviews experimental works on biomass gasification in these types of reactors and discusses the effect of the operating conditions (temperature, gasifying agent, diameter, residence time and ash effect) in the current used approaches to identify the existent gaps, such as related to impurity release and handling. It was shown that the presence of ashes catalyzes the conversion of tars, inhibiting the formation of soot during biomass gasification. The retrieved information is anticipated to be useful for researchers, end users as well as energy planners.

Microalgal cultivation in wastewater can significantly reduce the nutrient requirements and helps in wastewater management. In this study, Chlorella protothecoides was cultured on cigarette butt leachate admixed with culture medium. The cigarette butt leachate concentrations in the culture medium were set from 0 % to 100 % and a maximum biomass production was achieved at 60 % concentration (1.24 g L⁻¹). The lipid content of Chlorella protothecoides was increased by 9.98 %, carbohydrate content by 40.93 % and protein content by 42.93 % with 60 % of cigarette butt leachate concentration as compared to the control. Water quality analysis after microalgal cultivation revealed that the N and P elements in the cigarette butt leachate wastewater were removed completely by the microalgal growth. Life cycle assessment (LCA) analysis was carried out to evaluate the environmental sustainability of the process, which has revealed that the cigarette butt leachate wastewater has significant reduction in the environmental impacts with a CO₂ emission reduction up to 338 %. The study empirically suggested that the cigarette butt leachate mixed culture medium has potentially promoted the growth, lipid and protein in Chlorella protothecoides which can improve the upstream economics along with the environmental benefits of waste management.

In this paper, the activities of signal molecule AI-2 in the sole fermentation of Lactiplantibacillus plantarum and co-fermentation of Saccharomyces cerevisiae and L. plantarum were investigated. Co-fermentation of S. cerevisiae and L. plantarum was found to reduce L. plantarum to secrete AI-2. Three AI-2 quorum sensing inhibitors (DMHF (2,5-Dimethyl-4-hydroxy-3-(2H)-furanone), D-Rib (d-Ribose), and D-Gal (d-Galactosamine)) were added to the co-fermentation system to further interrupt the growth of L. plantarum. It was found that 0.2 g/L DMHF or 18.0 g/L D-Gal could mainly decrease the activity of AI-2 by 38 % and 36 %, respectively, and significantly inhibit the biofilm formation of L. plantarum. Moreover, the ethanol concentrations of the co-fermentation trials added with 0.2 g/L DMHF or 18.0 g/L D-Gal were 14 % and 103 % higher than that of the control, respectively, within 30 h of fermentation. This study provides basic data for the novel prevention of L. plantarum contamination in bioethanol production via quorum sensing control, which is meaningful for the environmental protection and the sustainable development of bioethanol industry.

This study aimed to develop a generalized allometric model to predict the aboveground biomass (AGB) of various bamboo species. Four crucial bamboo species, namely, makino bamboo (Phyllostachys makinoi), moso bamboo (Phyllostachys pubescens), thorny bamboo (Bambusa stenostachya), and ma bamboo (Dendrocalamus latiflorus), were used. This study collected data from previous studies with sample sizes of 90, Diameter at breast height (DBH), culm height (H), and age (A) were used as independent variables to develop three models for predicting AGB, where Model I used only DBH, Model II used DBH and H, and Model III used DBH, H, and A as independent variables. The results showed that Models II and III were superior to Model I based on the root mean square error (RMSE). Moreover, Model III only slightly improved the AGB prediction compared with Model II. This study also evaluated the predictive ability of the models for bamboo species based on the bias and RMSE values. The bias value helps to assess whether the AGB of a single bamboo species is under- or overestimated when that value appears positive or negative in the models. The RMSE values were higher for makino and ma bamboo in Model III when comparing the RMSE values for each bamboo species between Models II and III. However, it was higher in moso and thorny bamboo in Model II. Therefore, it was difficult to infer which model was better for all species because the ability to predict AGB was inconsistent among species for these two models.

Winter rye (Secale cereale) (WR) can be harvested as a biofuel or forage crop to increase farm profitability while reducing soil erosion and mitigating nutrient loss during the fallow period in a corn (Zea mays L.)-soybean (Glycine max L.) rotation. Precision planting, in which the cash crop row is skipped (STCR) to create non-intersecting zones of WR and corn growth, has been introduced to reduce the costs associate with planting of WR and also to alleviate the negative impact of WR on following corn. We conducted five site-years of field experiments in Southern Illinois to compare the impact of STCR versus conventionally planted (intersecting rows of WR with cash crop; NP) WR on biomass, biofuel and forage quality, and economic benefits (potential savings in seed costs with potential for increase in quality of biomass for sale). Our results indicated that STCR had a similar leaf area index (LAI) (1.96) and biomass yield (2.52 Mg ha⁻¹) to NP (1.72 and 2.33 Mg ha⁻¹, respectively). Cellulose and holocellulose (cellulose + hemicellulose) concentrations of WR, which are associated with higher ethanol production, were increased by STCR relative to NP. However, hemicellulose and lignin concentrations were similar between the two planting methods. The STCR decreased forage quality potentially through increased tillering due to the reduction in seeding rate by skipping the cash crop row. Relative forage quality (RFQ) was decreased by the STCR as compared to NP. However, the RFQ in STCR was high enough (>151) that did not influence its economic value. Thus, we recommend STCR over NP for biofuel and forage production.

The large-scale cultivation of photosynthetic bacteria requires significant quantities of fresh water. Screening strains that can thrive in brackish water or seawater is a solution to mitigate the dwindling availability of freshwater. Through phylogenetic analysis based on 16S rDNA sequences, this study identified a strain Rubrivivax gelatinosus MBE isolated from seawater. The effects of several key factors, including carbon sources, pH, NH₄⁺ and NaCl concentration on hydrogen production performance were investigated. Rubrivivax gelatinosus MBE showed a preference for glucose, but not organic acids for hydrogen production. It also exhibited alkalinity, achieving its peak hydrogen yield of 4626.82 ± 155.65 mL⋅L⁻¹ at pH 8. Interestingly, Rubrivivax gelatinosus MBE could exploit ammonium nitrogen for hydrogen synthesis, thriving even in specific ammonium and salt concentrations. Its resilience was further highlighted by a maximum hydrogen production yield of 4741.41 ± 167.01 mL⋅L⁻¹ and a hydrogen production rate of 37.59 ± 3.37 mL⋅L⁻¹⋅h⁻¹ with 10 g⋅L⁻¹ NaCl, underscoring its significant salt tolerance. These results suggested that Rubrivivax gelatinosus MBE could be a promising candidate for biofuel production, and it is significant to take sustainability study on the application of MBE to deal with alkali wastewater from paper making, pharmacy and printing and high salinity wastewater in the future.

In the present research, a novel solar-biomass hybrid cogeneration energy system is designed to operate in all weather condition where biomass and Direct Normal Irradiance (DNI) both are available. The proposed model integrates the Rankine cycle with an ejector and absorption refrigeration cycle, which utilized the low-temperature energy source available at the exit of the steam turbine and Heat Recovery Steam Generator (HRSG) to produce power and cooling simultaneously. The solid waste, rice husk, sugarcane bagasse and apple bagasse biomasses are used in the fluidized bed gasifier. First and second law analysis tools are used in order to assess the performance of the cogeneration energy system. The results find out the effects of some parameters on first and second law efficiencies when operated on both biomass and solar energy. The overall first and second law efficiencies of the system are found to be 42.29% and 39.72% for solid waste ranking 1 amongst all the four biomass materials respectively. A slight gain in the first and second law efficiencies 62.1% and 27.71% was observed after a considerable increase in the value of DNI at different operating conditions. The overall cycle efficiency is increasing due to cogeneration system and it is economically viable option because solar energy is freely available everywhere.

Second-generation biofuels may show great potential for decoupling fossil fuel reliance and environmental deterioration. This study aimed to characterize the dependency, drivers, and gas-to-ash products of the combustion of Pennisetum hydridum (PHY). The activation energy of the two main combustion stages and their best-fit mechanism models were 221.01 kJ·mol⁻¹ (F4) and 191.59 kJ·mol⁻¹ (D1) in the air combustion and 202.26 kJ·mol⁻¹ (F3.5) and 199.09 kJ·mol⁻¹ (D3) in the oxy-fuel combustion. High atmospheric concentration of CO₂ delayed the peaks of the mass loss curve, increased the release of C-containing products (CO, CH₄, and some small molecule organic matters), decreased or delayed the release of N-containing products (HCN and NH₃), and reduced the slagging risk of ash, presenting a loose and porous structure. Owing to the high K content, part of K formed K₂SO₄ and KCl, finally decomposed into gaseous products, with remaining K being retained in the ash as silicates and aluminosilicates. The maximized energy performance and the minimized emissions of gaseous products were jointly optimized in the combustion range of 500–993 °C. Findings of this study can provide insights into a better development of the comprehensive utilization of PHY from the perspective of bioenergy efficiency and eco-friendly disposal.

This study evaluates different fermentation strategies to produce 2,3-butanediol (2,3-BD) from banana industry waste, such as whole bananas (fruit + peels) and banana peels, selecting the most favorable from a technical and economic point of view. Both residues have enough free sugars (17.8 %–35.8 %), glucan (11.0 %–14.2 %) and hemicellulose (2.8 %–6.3 %), to be promising substrates for 2,3-BD fermentation. Saccharification was studied by comparing enzymatic hydrolysis, hydrothermal pretreatment, and hydrothermal pretreatment followed by enzymatic hydrolysis. Different fermentation scenarios were also compared regarding the 2,3-BD yield and productivity: Separate Hydrolysis and Fermentation (SHF), Simultaneous Saccharification and Fermentation (SSF), and direct fermentation without prior saccharification using Paenibacillus polymyxa DSM-365 as the fermenting microorganism. The results showed that the pretreatment step was not necessary to improve the release of fermentable sugars. Enzymatic hydrolysis was the most effective alternative for maximizing sugar recovery, reaching sugar concentrations of 18.1 g/L (recovery: 92.5 %) for banana peels and 33.3 g/L (recovery: ∼100 %) for whole bananas. The SSF strategy led to higher 2,3-BD concentrations of 15.0 g/L and 26.6 g/L for banana peels and whole bananas, respectively. The preliminary economic analysis indicated that SSF and direct fermentation could be the more cost-effective process alternatives for banana peels and whole bananas, respectively. Thus, it was demonstrated that banana waste is an interesting resource for the production of 2,3-BD. The bioprocess can be competitive when using a low-cost raw material and reducing the number of process steps compared to traditional technologies.