Biomass Conversion and Biorefinery最新文献

Indonesia as the world’s largest palm oil producer produces large amounts of waste during palm oil processing, one of which is oil palm empty fruit bunches (OPEFB). OPEFB can be converted into biochemicals, bioethanol, and lignin. This study aims to produce bioethanol from OPEFB using response surface method (RSM) analysis with the addition of the bleaching process and Cellic® Ctec2 and Cellic® Ctec3 enzymes used in the saccharification process. In addition, lignin was isolated from black liquor in the pretreatment process with the CO₂ bubbling method. Bioethanol production begins with pulp production by the alkaline (NaOH) steam explosion of OPEFB followed by bleaching. Subsequently, enzymatic saccharification with three parameters: enzyme concentration, solid loading, and temperature, was carried out. Saccharomyces cerevisiae was used in the fermentation to produce ethanol. Meanwhile, the lignin isolation was carried out by injecting CO₂ gas 2 L/min into the black liquor solution with variations in time. The results showed that the bleaching processes significantly increased cellulose content and reduced lignin content in OPEFB, with pulp yields reaching 91% and 89% for the first and second stages of bleaching, respectively, demonstrating high efficiency in preparing materials for sugar recovery. Optimal conditions were achieved using RSM analysis at an enzyme concentration of 30 FPU, solid loading of 20% (w/v), and temperature of 50 °C with a sugar content of 12.63% and ethanol of 2.14%. The implication of the bleaching process showed a lower concentration of 1.2% ethanol when compared to only unbleached pulp which produced 2.42% ethanol. In addition, the use of Cellic® Ctec3 enzyme produced higher sugar and ethanol content with 14.04% sugar and 4.42% ethanol compared to Cellic® Ctec2. On the other hand, the largest lignin isolation result was obtained at a processing time of 2 h with a yield of 1.16% and purity of 96.94%.

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In this study, we propose an eco-friendly approach for synthesizing carbon quantum dots (CQDs) utilizing potato peel as a carbon precursor via a highly efficient one-step hydrothermal method. The structural and chemical properties of the CQDs were comprehensively analysed by employing various techniques. Furthermore, UV–vis and fluorescence spectroscopy were utilized to scrutinize the optical characteristics of the CQDs. The synthesized CQDs exhibit enduring fluorescent attributes, commendable biocompatibility, and a satisfactory quantum yield of 12%. Subsequently, the adsorption efficiency of the nanomaterial was evaluated using methylene blue (MB) dye. Impressively, the CQDs displayed exceptional performance in removing cationic dye, retaining over 78% of removal efficacy even after the fourth cycle of adsorption and desorption, thus indicating robust adsorption capability and reusability. The adsorption kinetics were governed by the pseudo-second order, while the adsorption isotherm adhered to the Freundlich model (R² = 0.99). The thermodynamic study indicates that the adsorption process is spontaneous (∆G° = − 21.932 kJ mol⁻¹), exothermic (∆H° = -3.95 kJ mol⁻¹) and involves an increase in randomness (∆S^° = 0.054 kJ mol⁻¹ K⁻¹) at 333 K. Furthermore, it has been demonstrated that CQDs exhibit anticancer properties against MCF-7 breast cancer cells. The half-maximal inhibitory concentration (IC₅₀) of CQDs, which indicates the concentration necessary to decrease cell viability by 50%, was determined to be approximately 64 μg mL⁻¹.

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Sulfur accumulation during biofuel production is pollutive and toxic to conversion catalysts and causes the premature breakdown of processing equipment. Air classification is an effective preprocessing technology for ash and sulfur reduction from biomass feedstocks. A life cycle assessment (LCA) sought to understand the environmental impact of implementing air classification as a sulfur-mitigation technique to improve feedstock quality for pine residues using a grid electricity scenario (GES) versus a bioelectricity scenario (BES). Global warming potential (GWP) for preprocessing was simulated using inventory databases embedded in SimaPro and the Argonne National Laboratory’s GREET model, specifically focusing on comparing the GWP of a GES versus a BES. Overall, the GES had a GWP impact over seven times that of the BES (136 versus 18 kg CO₂ equivalent per tonne of usable feedstock), with steam generation during rotary drying accounting for 57% of the GES’s GWP. Air classification represents 0.4% and 1.6% of the total GWP impact for the GES and BES, respectively. Therefore, air classification can facilitate a 30% reduction in feedstock sulfur content to improve feedstock quality for biofuel conversion and lessen corrosion of equipment while contributing minimal GWP impact during preprocessing.

The present work investigates the co-pyrolysis of rice straw (RS) and polystyrene (PS) using a thermogravimetric analyzer to understand the kinetics and synergistic effect between the two feedstocks. Seven samples, namely, RS, PS, PS 0.05 (5 wt.% PS), PS 0.1 (10 wt.% PS), PS 0.2 (20 wt.% PS), PS 0.3 (30 wt.% PS), and PS 0.4 (40 wt.% PS) are used for the analysis. Two pyrolysis performance indices: devolatilization index (DI) and heat resistance index (HRI), are estimated to respectively analyze the volatiles release potential and thermal stability of the samples. Activation energy values are estimated using seven different iso-conversional models whereas the pre-exponential factor (A) is determined by the Kissinger equation and reaction order is determined using Avrami theory. The average apparent activation energy for different blends varies from 140.26 kJ/mol to 224.17 kJ/mol, with a minimum value obtained for PS 0.3 (135.71 kJ/mol) followed by PS 0.1 (139.95 kJ/mol) and PS 0.05 (140.27 kJ/mol). The reaction order concerning different temperatures and Criado master plot results reflect that RS, PS, and their respective blends followed a complex pyrolysis/co-pyrolysis reaction mechanism. The kinetic parameters gained via the most accurate Vyazovkin method are used to estimate Gibbs free energy (∆G), enthalpy (∆H), and entropy (∆S) values. The estimated kinetic and thermodynamic parameters predicted PS 0.05, PS 0.1, and PS 0.3 as attractive blends for co-pyrolysis. Additionally, an artificial neural network (ANN) model is developed to predict the thermal decomposition of samples based on temperature, heating rate, and blending ratio. This study provides essential information for understanding the reaction mechanism and reactor design for RS and PS co-pyrolysis.

Over millennia, natural fibres have been utilised to create essential materials for human life, and as a result, their properties have evolved to enhance their utility, durability, and aesthetic appeal. According to this study, polyethene materials can be replaced by fibres from sugarcane bagasse (Saccharum officinarum), which will have a less negative effect on the environment. Advanced techniques were employed to extract the fibres, and a comprehensive analysis of the physical chemical and mechanical properties was conducted. The study analysed the variations in the fibres’ aspects, along with the impacts of the mercerization. The key objectives of this research include optimising alkalization parameters to enhance fibre properties, evaluating their potential in composite materials and bio-based products, assessing environmental impacts, and addressing gaps in current knowledge. The study contributes to advancing sustainable materials science and engineering practices centred around sugarcane bagasse fibres by filling these research needs. After alkali treatment, SB fibres’ cellulose content increased by 27 to 32%. The mechanical qualities have improved by around 36–45% due to the NaOH treatment process, indicating that these fibres can replace plastic trays.

Chemical looping gasification (CLG) of biomass is an emerging technology for producing synthetic gas with high content in H₂, CO, and other valuable compounds in alternative to O₂-enriched gasification, an oxygen carrier delivering O₂ to the fuel. In the present paper, the results of CLG experiments at the bench scale are presented with a particular focus on the conversion of biomass char that is the least reactive but most energetic constituent of biomass. Synthetic Cu oxygen carrier and CO₂-enriched atmosphere were used at temperatures of 900 and 945 °C in a fluidized bed. In inert conditions, the char conversion was not complete for the fixed equivalence ratio that was adopted. Conversely, char was fully converted in the presence of CO₂, thanks to the inverse Boudouard reaction. The results show that higher temperature is preferable for thermodynamic reasons, although the related energy balance reduces the range of auto-thermal operability. The CO produced upon combined gasification by O₂ and CO₂ achieved a yield very close to the theoretical value of 78 mmol per gram of char at 100vol% CO₂ and 945 °C.

The natural composite trend emphasizes the use of renewable resources that possess enhanced qualities, boosting environmentally friendly solutions and minimizing the carbon footprint in numerous sectors. The present investigation aims to utilize sustainable biochar elements as reinforcements in polymeric composites. Biochar materials were produced using the pyrolysis process using waste biomass from cashew and bael fruit shells. Composites were created through the use of polypropylene (PP) as the matrix and biochar materials as the reinforcement. The three distinct weight percentages of filler were used, specifically 2.5%, 5%, and 7.5 wt.%. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and proximate analysis were used to examine the surface morphology, crystalline structure, and fixed amount of carbon in the synthesised biochar materials. The flammability properties, such as the maximal heat release and smoke production, were assessed using cone colorimeter analysis. The materials containing 5% bael fruit shell biochar had a significant increase in tensile strength, exhibiting 54.66% greater strength in comparison to pure PP. The hardness and durability of composites decreased as a result of inadequate interfacial bonding when the filler content was increased from 5 to 7.5%. The inclusion of biochar resulted in a considerable reduction in both the maximum rate of heat release (MRHR) and smoke generation of the biocomposites. Specifically, the MRHR decreased from 1083 KW/m² for pure polypropylene to 584.36 KW/m² for biocomposites containing 7.5 wt.% of bael biochar. Thermogravimetric studies revealed that the addition of biochar materials greatly improved the thermal integrity of the composites. The materials containing 5 wt.% bael biochar demonstrated enhanced heat resistance, resulting in a residual mass of 8.32%. It is clear that biochar-based polymers are potential materials for diversified industrial applications, especially in the automotive industry, where the enhanced strength and thermal stability of components such as interior panels, dashboards, or under-the-hood parts are important. Biochar made from waste biomass can also help reduce waste and promote sustainability, with numerous environmental benefits.

Throated downdraft gasifiers have the high tendency to pressure drop that hinders the smooth operations of these reactors. The ratio of gasifier throat diameter to gasifier diameter has an unprecedented impact on the pressure drop of downdraft reactors. The main aim of this study is to investigate the effect of reducing the throat on pressure, velocity, turbulence, and temperature in the reduction and oxidizing zones of the gasifier through computational fluid dynamics. The recorded data indicated a significant increase in both turbulence and velocity by 16% and 21% respectively, while there was a marginal increase in the pressure drop when T_R0.12 and T_R0.40 models were compared. The gasification temperature tremendously improved as the throat ratio is decreased from 0.40 to 0.12. Additionally, the gasifier performance in terms of carbon conversion, cold gas, gasification efficiencies as well as heating values are also dealt with. The results show that lower throat ratios increase the carbon conversion, heating value, and cold gas efficiency of the process to the tune of 8.61%, 15.3%, and 8.58% respectively when the T_0.12 and T_R0.40 were compared.

The aim of this investigation was to evaluate the efficiency of unicellular microalga Chlorella pyrenoidosa cultivated in dairy industry wastewater for CO₂ sequestration and its influence on biomass and lipid production. For this purpose, three process parameters—CO₂ (2–10%), wavelength (420–680 nm), and temperature (20–50 °C)—were optimized using the central composite design (CCD) with response surface methodology (RSM). A total of twenty sets of experimental runs obtained by CCD were studied to optimize the process parameters for maximum biomass (mg L⁻¹), CO₂ fixation (mg L day⁻¹), and lipid yield (%). The highest biomass yield of 1.43 g L⁻¹ and maximum CO₂ fixation of 14.55 (mg L day⁻¹) were obtained with 5% CO₂, a temperature of 35 °C, and a wavelength of 520 nm. On the other hand, a maximum lipid yield of 34.21% was obtained with 5% CO₂, a temperature of 35 °C, and a wavelength of 420 nm. The most influential binary interaction among the selected variables for biomass production and CO₂ sequestration was found to be LED + Temp > CO₂ + Temp > CO₂ + LED. Meanwhile, the behavior of lipid content was highly influenced by the interaction of CO₂ + Temp > CO₂ + LED > LED + Temp. The highest degree of positive correlation was observed between biomass yield and CO₂. Fourier transform infrared spectroscopy (FTIR) reveals a strong signal at 1400–1700 cm⁻¹, confirming the existence of a carbonyl group (–COOR–).

The urgency to mitigate greenhouse gas emissions has catalyzed interest in sustainable biomass production and utilization coupled with carbon capture and storage (CCS). This review explores diverse facets of biomass production, encompassing dedicated energy crops, agricultural residues, and forest residues, along with sustainable production practices and land management strategies. Technological advancements aimed at enhancing biomass yields, including precision agriculture, genetic engineering, and advanced processing technologies, are examined. Thermochemical methods (gasification, pyrolysis) and biochemical methods (anaerobic digestion, fermentation) for biomass conversion are detailed, highlighting their roles in biomass utilization. Integrated biorefineries are emphasized for maximizing biomass efficiency. The review thoroughly covers CCS, including CO₂ capture and transport advancements, innovative storage solutions, and challenges in implementation. Bioenergy with carbon capture and storage (BECCS) strategies for achieving negative emissions are discussed, with insights from case studies like the BIO-CAP-UK project and initiatives in New South Wales, Australia. This review provides a comprehensive overview of sustainable biomass pathways and their critical role in CCS, offering insights into current technologies, limitations, and concluding with implications for climate change mitigation strategies.