Biofuels Bioproducts & Biorefining-Biofpr最新文献

Despite bioenergy playing an important role in producing a significant amount of renewable energy in the EU, there are several differing views of its future role, as illustrated in the European Parliament and society more generally. The aim of this paper is to investigate the barriers to advancing bioenergy use and prospects for the future of bioenergy in the EU. Whereas previous studies have focused on specific aspects of EU bioenergy, such as market structure, technological considerations, and individual forms of bioenergy, this study provides results from a survey analyzing several factors that are inhibiting overall bioenergy development throughout the EU. The results show that, in general, the growth of bioenergy use in the EU can be expected to continue, although there are many issues that need to be addressed by society and through policy implementation. The most important of these issues include the relationship between the future role of the fossil fuel using industry and bioenergy, addressing the inadequate and currently confusing level of policy support, and responding to the perception of low public acceptance, reflected by pressure from some nongovernmental organizations to reduce the use of bioenergy. The study shows that biomass is not always the best option in economic terms, and other options such as heat pumps powered by green electricity or natural gas can be more financially attractive. To ensure the continuing development of the bioenergy field in the EU, it is important to increase local policy support for bioenergy, decrease imports of fossil fuels from non-EU countries, increase investment in the bioenergy sector, and engage in effective and fact-based education about, and promotion of, bioenergy.

Reductions in greenhouse gas emissions are necessary to slow global warming and decrease the likelihood of irreversible climate scenarios. There is thus an urgent need for low-emissions fuels. This study conducted a techno-economic analysis of two different industrial plant concepts for producing hydrogen from woody biomass. One was a large-scale centralized 60 MW_H2 option using dual fluidized bed gasification with CO₂ removal. The other was a small-scale decentralized 1 MW_H2 option using fixed-bed gasification without CO₂ removal. Mass and energy balances were calculated by the process simulation software IPSEpro. Key performance indicators, including technical, economic, and environmental parameters, were derived. Overall energy efficiencies of 64.2 and 59.5% and hydrogen yields of 87 and 68 g_H2 kg⁻¹_BM.db were determined for hydrogen production by dual fluidized bed and fixed-bed gasification, respectively. The levelized costs of hydrogen amounted to 5.6 and 15.0 €₂₀₂₂ kg⁻¹_H2 and agreed quite well with values from the literature. Flexible and decentralized heat, electricity, and hydrogen production based on fixed-bed gasification within a multiproduct plant were also evaluated. The results show that the multiproduct plant could be economically feasible if at least 63% of the annual operating hours were dedicated to hydrogen production, and assuming a hydrogen selling price of 17.5 €₂₀₂₂ kg⁻¹_H2 in Austria. In conclusion, both of the processes that were evaluated are conceivable technologies for the transition of the energy system towards renewable energy sources from a technical and economic point of view, although small-scale hydrogen production is considerably more expensive.

Coffee consumption is a daily habit for the majority of people worldwide, resulting in consistently large amounts of residue. Spent coffee ground (SCG) is the residue obtained during the brewing process. It represents an abundant source of energy biomass, or raw material for added value products but it is still largely unexploited. This residue may find several applications, such as in polymers/composites precursors, solid/liquid biofuels, biofertilizers, and so forth. The aim of the present paper was the pilot production of pellets by mixing SCG and other residual biomass feedstock. Coffee residues were mixed at different ratios (0, 10, 30, 50, 70, 90 wt%) together with: (i) forestry residues; (ii) sawmill residues; (iii) urban prunings; (iv) maize residues; (v) peach prunings; and (vi) miscanthus. Samples of each fuel mixture were analyzed at the Solid Fuels Laboratory of CPERI/CERTH (Chemical Process and Energy Resources Institute/Centre for Research and Technology Hellas) in Greece by applying established standards. The results of the analyses show that the mixing of biomass residues with coffee could result in competitive solid biofuels. More specifically, pellets with up to 10% coffee residues, mixed with sawmill residues, complied with the class A2 limits set by the international standard ISO 17225-2 for wood pellets, and pellets with up to 30% coffee residues complied with the class B limits for wood pellets for commercial/residential applications. Urban prunings mixed with 10 wt% coffee residues are within the limits set for class B wood pellets.

The global leather industry generates large quantities of tannery waste. These leather wastes have a high fat content, which could be used for valuable products. This study focuses on the conversion of such fats into a biocrude to be distilled into a bio-based hydrocarbon fuel blendstock. A biorefining technology defined as ‘gas-phase catalytic cracking’ (GCC) over activated carbons, also referred to as ‘greasoline’, was used for conversion, and GC–MS/FID and simulated distillation for product characterization. The experiments were performed at ambient pressure and 450 °C reaction temperature, with 40 g h⁻¹ of fat being processed over 55 g of steam-activated carbon under a nitrogen atmosphere for a duration of 4 h. Fleshing oil obtained from the pre-fleshing of double-face lambskins by extraction with supercritical CO₂ yielded almost the same mass fraction of organic liquid product (OLP) (59 wt%) as palm oil used as a reference (62 wt%). In both OLPs, n-alkanes from heptane to heptadecane predominate, with a clear predominance of n-pentadecane and n-heptadecane and no unsaturated molecules among the major components. For both oils, about 85 wt% of the OLP is in the boiling range of diesel fuel, and about another 12 wt% is in the gasoline boiling range. The results show that mixtures of fatty acids extracted from leather tanning wastes can be used for value-added products – in particular for the production of bio-based hydrocarbon fuel blendstock.

Liquid-phase exfoliation, a technique for enhancing the properties of biochar, has been recognized as effective, circumventing the limitations of other methods such as high expenses, scalability, and complexity. This study explored the synergistic effect achieved by combining chicken feathers with elephant grass to create a composite feedstock for biochar production. The biochar was subjected to liquid-phase exfoliation using acid and acetone. Elemental analysis indicated that the co-carbonization of the combined biomass produced an enriched hybrid biochar. The oxygen content in both exfoliation routes (acid and acetone) increased, with an increase and decrease in carbon content in acetone and acid exfoliation, respectively. Textural analysis revealed significant enhancement, with surface areas of the acid-exfoliated biochar more than twice the size of the hybrid biochar. The pore volume of both exfoliated samples was double that of the hybrid biochar. Microscopic surface examination revealed rougher, porous structures in the exfoliated biochars in comparison with the smooth, cohesive surface in hybrid biochar. Functional group analysis showed the presence of aromatic rings, a carbocyclic group, and an alkene, suggesting potential applications in adsorption. This study provides an efficient method for using liquid-phase exfoliation to enhance biochar properties, benefiting industries reliant on biochar production and biomass utilization by improving product quality, sustainability, and environmental impact.

Bamboo, recognized for its rapid growth, high yield, and fiber performance is prominent in the fiber-based bioproduct industry. However, the absence of US industrial bamboo plantations for fiber production necessitates reliance on imports or locally manufactured products using imported bamboo fibers, predominantly from China. This study evaluates the economic viability of cultivating bamboo in the Southern US for fiber production, with a case study on hygiene tissue products. The supply-chain analysis was assessed to calculate bamboo chips' minimum selling price (MSP) at the farm gate for an 8% internal rate of return (IRR). The MSP, influenced primarily by land rental costs, ranges from USD 48 to 55 per bone-dry metric ton (BDt). Despite an initial establishment cost of ~USD 2 000 ha⁻¹ and profitability by year 5, bamboo is a viable, long-term fiber alternative. Successful bamboo cultivation in the US could lead to a more sustainable implementation of alternative non-wood fibers for hygiene tissue applications.

A combination of different physio-chemical treatment steps was applied to purify industrially derived crude glycerol at laboratory scale. The full process included acid–base treatments, phase separation, and adsorption, and the glycerol purity and recovery were optimized by varying the pH during saponification and acidification, the solvent-to-glycerol ratio, and type of base used in the process to enhance both. The testing campaign resulted in a final purity of up to 87% wt starting from a very low-quality ‘end-of-life’ waste glycerol sampled from different refineries. The net glycerol recovery at laboratory scale reached 42% of the initial glycerol in the feedstock and the maximum ash removal exceeded 90% given the low quality of the feedstock and high content of impurities and the attempt to achieve high glycerol recovery. The experiment showed that mild operations such as saponification with KOH (pH of 8), acidification with H₃PO₄ (pH of 6), an ideal 2-propanol to glycerol volume ratio equal to 3 and potassium hydroxide as a base for the neutralisation step were the optimum conditions despite the differences between samples. The sequence of the processes proposed was therefore considered a viable option to treat any kind of crude glycerol to make it profitable for fuel and chemical applications.

Recent studies have used nanoparticle additions to enhance the fuel properties of biodiesel. However, it is unclear how these additives would affect engine operation. The effects of commercial nanoadditives on engines have been the subject of several studies. The current study focuses on nanoparticles derived from agricultural waste – specifically rice husk (RH) – to enhance their value. This study therefore examined silica (SiO₂) doped with Adansonia digitata methyl ester (ADME) and tested it in a diesel engine. All nanofuel blends were prepared using an ultrasonication process, incorporating 400 ppm of SiO₂ nanoparticles, fuels, and 1% surfactants. The results revealed that the brake thermal efficiencies (BTE) at maximum brake power (BP), for B20, B20 + SiO₂, B100, and B100 + SiO₂ fuels, were 29.9%, 28.2%, 28.44%, and 27.1%, respectively. Brake-specific fuel consumption (BSFC) was also reduced when the engine ran from 4 to 16 kW BP. The exhaust gas temperature (EGT) of B100 and B100 + SiO₂ increased more than that of B20. The peak heat release rates (HRR) of the B100 + SiO₂ and B20 + SiO₂ were slightly higher by 2.9% and 2.6%, respectively than the neat B100 at medium BP. However, in-cylinder gas pressure (CGP) increased in the following order: B20 + SiO₂ < B20 < B100 < B100 + SiO₂ < B0. Moreover, the exhaust emissions of nanofuel blends showed a greater reduction in CO, total hydrocarbon (THC), CO₂, NO_X, and particulate matter (PM) in comparison with B20 and B100. Overall, this study recommends that SiO₂ nanoadditive is a beneficial substitute fuel additive to use with biodiesel and its blends due to enhanced engine performance efficiency and reduced emissions.

Interest has emerged recently in addressing the long-standing issue of waste plastic disposal and environmental challenges through the co-liquefaction of waste plastics with eco-friendly renewable biomass resources, including microalgae biomass and lignocellulosic biomass, to produce biofuels. Co-liquefaction provides a viable alternative for managing plastic waste while contributing to biofuel production. The purpose of this article is to provide a comprehensive review of the advances in the co-liquefaction of various mixtures of plastic waste and different types of biomass feedstocks (lignocellulosic and algal) for the production of biofuels.

The influence of various reaction parameters, such as feedstock composition (blending ratio), temperature, catalyst type and loading, solvents, and reaction time on the product yield are explored. The synergistic interaction during the co-liquefaction of biomass and plastic and the distribution and properties of biofuel products are also discussed.

The findings demonstrate that maximum product yields vary depending on the final temperature, and the blending ratio plays a crucial role in determining the distribution of liquefaction products. Of particular interest is biocrude oil, the components of which are influenced by the composition of the feedstock material. The distribution of organic elements in the biochar is contingent upon the type of plastic used. Although the analysis of gas-phase components is often overlooked, the reaction medium's composition is shown to impact the resulting gas composition.

Finally, based on the insights gleaned from the literature, this review presents future perspectives on the subject matter. In general, the co-liquefaction process offers a viable option for sustainable biofuel production and is a promising approach to address the waste plastics disposal challenges effectively, contributing to the valorization of plastic waste to achieve a circular bioeconomy in the future.

Areca nut husk (ANH) holds promise as a viable biomass source for xylose production. Xylose is a precursor for various biochemicals. However, the recalcitrant nature of ANH makes saccharification more complex. To address this, lime and acid pretreatments were carried out to enhance the susceptibility of biomass to saccharification. Before this, a compositional analysis was conducted to determine the initial constituents of the feedstock. Saccharification was conducted under the following conditions: 2% (wV⁻¹) substrate loading, 100 rpm agitation, and 30 °C hydrolysis temperature for 12 h hydrolysis time at pH 4.5 to 5.0. However, parameters like xylanase enzyme loading were varied to enhance the saccharification of the ANH. The results demonstrated that acid-treated husk (ATH), lime-treated husk (LTH), and raw husk (RH) achieved the highest yield (gg⁻¹) of reducing sugar, approximately 90, 83, and 15%, respectively, at an enzyme loading of 15.0 IUg⁻¹. Various analytical techniques, including Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), zeta potential, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) were used to examine structural changes in the native, pretreated, and saccharified residues of ANH. The analysis revealed that a significant amount of partial crystalline and amorphous cellulose in the ANH biomass was hydrolyzed during the saccharification process. However, saccharification also led to the removal of amorphous substances, disruption of the crystalline structure, and conversion of crystalline regions into amorphous domains.