BioEnergy Research最新文献

The use of forest biomass could drastically reduce the environmental impacts of fossil fuel usage for heat and power in remote communities and can provide new opportunities for employment, retaining money inside communities. Here, we present the techno-economic feasibility of alternative gasification technologies for CHP uses in three remote off-grid communities in Canada. The analysis includes different scenarios of fuel price and operation costs, as well as two different feedstocks, wood pellets and wood chips. The results show potential for successful implementation, subject to planning on the specific conditions and location of the community. Power generation costs vary widely depending on the available biomass price, utilization of heat as well the power output of the system, ranging from about 0.25 CAD/kWh to over 1.20 CAD/kW. Economic support for biomass or removal of diesel subsidies would have a significant impact on biomass CHP implementations. The feasibility of the investigated systems is not dependent on the economics or technology itself but (i) availability of quality feedstock, (ii) utilization of heat for additional revenue generation, (iii) the utilization of the systems, (iv) community-driven bioeconomy alternatives and (v) carbon credit opportunities.

Burning agricultural biomass in the field significantly contributes to air pollution, particularly in the Indian context, where numerous cities have consistently ranked among the world's most polluted over the past few decades. The investigation endeavors to examine the potential utilization of cotton stalks as an environmentally friendly and sustainable energy source. During the investigation, biochar was generated through pyrolysis at temperatures of 300, 500, and 700 ˚C for 4 h, while hydrochars were produced via hydrothermal carbonization (HTC) at 180, 210, and 240 ˚C for the same duration. The findings revealed that hydrochar exhibited higher mass and energy yields, with mass yields of 60 ± 7% compared to 41 ± 10% for biochar, and energy yields of 87 ± 1% compared to 63 ± 5% for biochar. Elemental analysis results indicated an increase in carbon percentage with rising process temperatures, with carbon content increasing from 59% at 300 ˚C to 78% at 700 ˚C for pyrolysis, and from 49% at 180 ˚C to 63% at 240 ˚C for HTC. The biochar synthesized at 700 ˚C demonstrated the highest measured high heating value (HHV_m) of 29.83 MJ/kg, whereas for HTC, the HHV_m of 25.88 MJ/kg was reported for hydrochar synthesized at 240 ˚C. From the computed thermal kinetic parameters, it is evident that the biochars are more thermally stable than hydrochars and raw cotton. According to the Van Krevelen diagram, both biochar and hydrochar products exhibited improved fuel properties. The cumulative evidence suggests a ground-breaking potential for utilizing these char products as sustainable solid fuel alternatives.

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With the growing demand for sustainable energy solutions, renewable propane (rC3) can be a suitable alternative to fossil liquefied petroleum gas (LPG), with potential lower environmental impacts. This study aims to design and simulate a rC3 production process via hydrotreatment of vegetable oils (HVO) to access the technical performance of this route. A comparison between various feedstocks (soybean, sunflower, canola, and palm oils) and downstream processes, namely, cryogenic distillation and chemical absorption, is discussed. The results were evaluated in terms of the key performance parameters: rC3 yield, specific hydrogen consumption, specific energy consumption, and CO₂ emissions. Moreover, an artificial neural network (ANN) model was developed to predict the key performance parameters based on the triglyceride composition of vegetable oils. The rC3 yield was close to 5 wt% for all vegetable oils, and the highest yield was obtained via palm oil hydrotreatment. The rC3 purity obtained in both separation processes was greater than 90%, with chemical absorption separation resulting in lower CO₂ emissions and lower energy consumption than the cryogenic distillation process. The ANN application for predicting the key performance parameters based on triglyceride composition presented correlation agreement > 0.9930 with the simulation results.

The excessive availability of coffee-cherry processing residues has garnered attention, owing to potential environmental concerns associated with ground disposal. The current investigation aims to disclose the characteristics of two main coffee agroindustry residues, i.e., coffee pulp and parchment, as well as the resulting biochar which is produced without chemicals and low energy involved. The effects of washing raw biomass on biochar’s physical–chemical properties were investigated. The pre-washed samples were prepared through the following steps: washing, soaking for 20 h, draining, rinsing, and drying under sunlight for 3 days. A slow pyrolysis process was performed at 420 °C in a pilot-scale apparatus to produce biochar. The results show that the pre-washing of feedstock reduced the ash content in coffee pulp biochar from 28.23 to 11.93%. The ash content of coffee parchment biochar decreased from 9.68 to 5.66% as a result of the washing treatment of the raw material. Furthermore, coffee pulp biochar experienced a 25.8% reduction in surface area, while 14% of the coffee parchment was lost due to washing treatment of raw feedstocks. The findings presented in this study offer new insights that are crucial for evaluating the feasibility and advancing the development of a large-scale commercial process for managing coffee agro-industry residues.

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The energy crisis, climate change, and insufficient waste management practices are compelling factors driving research into sustainable waste-to-resource technologies. Anaerobic digestion, aiming to recover energy and nutrients from organic waste, aligns with the circular economy's principles. This paper provides a comprehensive overview of utilizing biodiesel byproducts for biogas production, exploring techniques for enhancing biogas yield and addressing associated challenges. Assessing the potential of biodiesel byproducts highlights their environmental sustainability and economic viability for biogas production. Non-edible seed cake, rich in nutrients, shows promise for significant biogas yield. Additionally, crude glycerol, easily biodegradable, is identified as a promising co-digester, aiding in digesting recalcitrant substrates. Empirical data reveals remarkable methane yield boosts, ranging from 14 to 226% when co-digesting with crude glycerol. Moreover, the resulting digestate enhances soil fertility, promoting healthier plant growth and productivity. Challenges in anaerobic digestion, such as substrate C/N ratio imbalance and recalcitrance, necessitate strategies like substrate pretreatment and co-digestion with compatible materials to optimize biogas yield. Furthermore, advancements in anaerobic digestion technologies are crucial for effectively converting biodiesel wastes into biogas. Additionally, interdisciplinary investigations, including techno-economic analysis, lifecycle assessment, and sensitivity analysis, are vital to enhance and validate the feasibility of anaerobic digestion for biodiesel byproducts. This review serves as a valuable resource for future utilization of biodiesel byproducts for biogas production.

The study aimed to examine the effects of adding biomass ash on the biochemical processes involved in fermentable sugar production. Corn stover was pretreated using several methods—hot water, dilute acid, alkaline, γ-valerolactone, and ionic liquid methods, each examined with ash loadings of 7.18% and 21.07%. The findings demonstrated that increased ash content adversely affected both pretreatment and enzymatic hydrolysis. Specifically, the total sugar yield was 3 to 16% lower at the higher ash content across all pretreatment methods, and up to 4.01% lower during enzymatic hydrolysis. For acidic pretreatment, the sugar yield decreased as ash content increased. In contrast, ash content had a lesser impact on alkaline pretreatment compared to acidic pretreatment. For example, using corn stover with an ash content as high as 22.65% resulted in only a 2.90% decrease in total sugar yield compared to corn stover without added ash. The primary reasons for the reduced sugar yield in higher ash biomass during acidic pretreatments were likely the neutralizing effect of the ash and decreased acid access to the substrates. During enzymatic hydrolysis, ash reduced the sugar yield by limiting enzyme access to cellulose.

This study investigates the structural and functional transformation of biochar derived from eucalyptus wood powder, rice bran, and bagasse under pyrolysis temperatures of 500 °C, 700 °C, and 900 °C. Using BET, XRD, Raman, FTIR, and particle size analysis, we quantified changes in porosity, crystallinity, and surface chemistry. BET analysis revealed that the highest specific surface area was observed at 500 °C, with eucalyptus biochar achieving 243.2 m²/g. However, at 900 °C, mesopore and macropore formation dominated, with a notable decrease in surface area. XRD and Raman data showed increased graphitization at higher temperatures, with eucalyptus biochar exhibiting the greatest graphitic structure at 900 °C. FTIR results indicated a significant reduction in functional groups at elevated temperatures, enhancing the biochar’s aromatic stability. Resistivity measurements showed a decrease in resistivity, with the resistivity of eucalyptus biochar after 900 °C pyrolysis and ball milling being as low as 0.0196 Ω/cm under 27.3 MPa pressure test, indicating its strong potential in conductive applications. These findings provide quantitative insights into optimizing biochar properties for environmental and energy applications.

This study compared the pyrolysis behaviors of corn stalk (CS) and its torrefied biomass after inert torrefaction (IT), oxidative torrefaction (OT), and wet torrefaction (WT), focused on the kinetic parameters and reaction mechanisms. Inert and oxidative torrefaction reduced volatile matter while increasing ash content and fixed carbon. Wet torrefaction reduced both volatile matter and ash content while increasing fixed carbon. Three pretreatment methods decreased oxygen content, increased carbon content, and had a higher heating value. The materials were pyrolyzed in a thermogravimetric analyzer. For CS, the average activation energy (E) values calculated by the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunosen methods were 62.5 and 60.07 kJ/mol. IT and WT showed increased trend, with values of 81.58, 81.48 kJ/mol and 69.75, 67.58 kJ/mol respectively. Conversely, OT decreased with the E values of 57.39 and 56.2 kJ/mol. Pyrolysis was divided into two stages based on various conversion rates (α) using Malek and Coats–Redfern methods. When α was below 0.5, a one-dimensional diffusion mathematical model described the pyrolysis process. When α was beyond 0.5, the pyrolysis of CS conformed to the cylindrical symmetric three-dimensional diffusion mathematical model, while IT, OT, and WT better fit the spherical symmetric three-dimensional diffusion mathematical model. However, the torrefaction atmosphere’s impact on the pyrolysis kinetic mechanism was limited, exhibiting no alterations in the diffusion model. Different torrefaction samples demonstrated a degree of homogeneity, considering the lower pretreatment temperatures and the economic feasibility of torrefaction atmospheres in oxidative torrefaction, coupled with the lowest activation energy of oxidative torrefaction products indicating more efficient pyrolysis, oxidative torrefaction was recommended as the torrefaction pretreatment process before pyrolysis engineering.

Residual biomass from agriculture is a highly promising resource for sustainable energy production. Its abundant generation and accurate estimation are essential for the development and implementation of efficient utilization strategies. However, the calculations proposed in the existing literature are often contradictory or exhibit impractically wide range. This study compiles residual biomass indices for cereal, oil, industrial, and arboreal crops. By evaluating and processing these indices, a refined set of modified indices is presented to enhance existing methodologies for calculating agricultural residues. The methodology establishes lower, average and upper bound scenarios for the residual biomass of selected crops and is applied to Greece to estimate its energy production potential. The findings suggest that Greece generates approximately 5.5 million tons of agricultural residues annually, ranging from 4.5 million tons (lower-bound) to 6.6 million tons (upper-bound). This biomass has the potential to produce 70,730 TJ of energy, corresponding to 8.4% of the country’s energy demands, with energy potential ranging between 55,644 and 82,635 TJ. The most noteworthy crops include olive trees, cotton, maize, vineyards and wheat since they account for 82% of the total estimated energy. Spatial analysis conducted at NUTS-2 and NUTS-3 levels highlights the Regions of Central Macedonia and Thessaly as having substantial potential for residual biomass to support energy conversion strategies.