Biomass Pyrolysis Research Articles

PIROLIZ REAKTORINING QOVURG‘ALI SIRTI ORQALI ISSIQLIK UZATISH SAMARADORLIGINI HISOBLASH

In this article, the thermal parameters of the biomass pyrolysis thermal processing device were calculated. Also, the flow of flue gas at a temperature of 500-600 ℃ during the pyrolysis process, its movement on the ribbed surfaces of the pyrolysis reactor, and its effect on the water boiler on the outer wall of the reactor were studied. The bioreactor is made of the "pipe in a pipe" type, pyrolysis of biomass takes place in its inner pipe, and water is heated in the outer pipe due to the heat lost to the environment. At the same time, the internal pipe of the reactor allows obtaining gaseous fuel by thermal processing of biomass, and the heat in the external pipe of the boiler solves the problem of providing consumers with hot water in the heating system. The proposed device thermally processes agricultural biomass waste and provides autonomous consumers with alternative fuels and thermal energy at the same time.

Computational Modeling of Biomass Fast Pyrolysis in Fluidized Beds with Eulerian Multifluid Approach

This study investigated the fast pyrolysis of biomass in fluidized-bed reactors using computational fluid dynamics (CFD) with an Eulerian multifluid approach. A detailed analysis was conducted on the influence of various modeling parameters, including hydrodynamic models, heat transfer correlations, and chemical kinetics, on the product yield. The simulation framework integrated 2D and 3D geometrical setups, with numerical experiments performed using OpenFOAM v11 and ANSYS Fluent v18.1 for cross-validation. While yield predictions exhibited limited sensitivity to drag and thermal models (with differences of less than 3% across configurations and computational codes), the results underline the paramount role of chemical kinetics in determining the distribution of bio-oil (TAR), biochar (CHAR), and syngas (GAS). Simplified kinetic schemes consistently underestimated TAR yields by up to 20% and overestimated CHAR and GAS yields compared to experimental data (which is shown for different biomass compositions and different operating conditions) and can be significantly improved by redefining the reaction scheme. Refined kinetic parameters improved TAR yield predictions to within 5% of experimental values while reducing discrepancies in GAS and CHAR outputs. These findings underscore the necessity of precise kinetic modeling to enhance the predictive accuracy of pyrolysis simulations.

Time-Dependent Analysis of Catalytic Biomass Pyrolysis in a Continuous Drop Tube Reactor: Evaluating HZSM-5 Stability and Product Evolution

This study investigates a continuous deoxygenation of bio-oil vapor in a catalytic fixed-bed reactor coupled to a continuous drop tube reactor (DTR) for biomass pyrolysis. Beech wood pyrolysis was initially examined without catalysts at various temperatures (500–600 °C). The products were characterised using GC-MS, Karl Fischer titration, GC-FID/TCD, and thermogravimetric analysis. The highest bio-oil yield (58.8 wt.%) was achieved at 500 °C with a 500 mL/min N2 flow rate. Subsequently, ex situ catalytic pyrolysis was performed using an HZSM-5 catalyst in a fixed-bed reactor at a DTR outlet, operating at 425 °C, 450 °C, and 500 °C. The HZSM-5 catalyst exhibited declining deoxygenation efficiency over time, which was evidenced by decreasing conversion rates of chemical families. Principal component analysis was employed to interpret the complex dataset, facilitating a visualisation of the relationships between the experimental conditions and product compositions. This study highlights the challenges of continuous operation as experimental durations were limited to 120 min due to clogging issues. This research contributes to understanding continuous biomass pyrolysis coupled with catalytic deoxygenation, providing insights into the reactor configuration, process parameters, and catalyst performance crucial for developing efficient and sustainable biofuel production processes.

Study on the carbon sequestration effect of biochar in vegetable fields

This study was conducted using a field experiment methodology aimed at assessing the effects of biochar application on tomato growth and soil properties in greenhouse greenhouses. Biochar, a carbon-rich material produced by pyrolysis of biomass under anoxic conditions, has attracted attention for its potential in soil amelioration, carbon sequestration, and soil fertility enhancement. In this experiment, three biochar application levels of 0, 20, and 40 t/ha were designed to investigate the effects of different application rates on soil chemical properties and tomato growth.The study results showed that biochar application significantly increased soil pH by 0.05 to 0.1 units, which was beneficial in regulating acidic soil. Meanwhile, biochar application significantly increased total soil carbon content by 7.5 to 28.8%, indicating its effectiveness in enhancing soil carbon sequestration capacity. Although the enhancement of total soil nitrogen content by biochar was small (3.1 to 7.8%), this increase had a positive effect on crop growth. Considering the cost-effectiveness, this study recommends a one-time application of 40 t/ha of biochar, which can maintain the effect for at least 2 years, reducing the need for frequent applications and the associated economic costs.This study provides recommendations for optimization of biochar application and provides a scientific basis for sustainable agricultural development. By improving soil properties and increasing crop yields, this study contributes to the promotion of green development of agriculture and ecological civilization, and the realization of carbon and nutrient cycling in agroecosystems.The significance of this research focuses on evaluating the effects of biochar on soil properties and tomato production, thereby providing a scientific basis for fine-tuning application levels. Such optimization promotes sustainable farming practices, reduces agricultural waste emissions, enhances carbon and nutrient dynamics within agroecosystems, and reinforces the scientific foundation essential for progressing green agricultural development and building an ecological civilization.

Chromium Isotope Fractionation During the Removal of Hexavalent Chromium by Oak-based Biochar

Chromium, especially in its hexavalent form (Cr(VI)), poses significant health risks due to its carcinogenic properties. Emerging research suggests that biochar, a carbon-rich material derived from biomass pyrolysis, holds promise as an effective and sustainable solution for Cr(VI) remediation. Biochar's unique physicochemical properties, such as its high surface area, porous structure, and functional groups, contribute to its exceptional adsorption capacity for metals. In a series of batch experiments with varying durations, an oak-based biochar was exposed to a 48 mg∙L⁻1 Cr(VI) solution. The results demonstrate that the biochar effectively removed 99% of the Cr(VI) after 100 hours, with a removal capacity greater than 5 mg∙g⁻1. Fourier transform infrared (FTIR) spectroscopy suggests that the removal of Cr(VI) involved aliphatic and aromatic C-H bonds. X-ray photoelectron spectroscopy (XPS) also indicated the role of aliphatic groups in the removal process and suggested the involvement of carbonyl groups. XPS analysis also detected both Cr(III) and Cr(VI) on the surface of the biochar, indicating the occurrence of reduction and sorption processes. The presence of Cr(III) and Cr(VI) was further confirmed at the Canadian Light Source (CLS) synchrotron facility using X-ray absorption near edge structure (XANES) spectroscopy. Cr isotope analysis showed an increase in δ⁵³Cr as the concentration of Cr in solution decreased, indicating Cr(VI) reduction. The isotope data followed a Rayleigh curve with a kinetic fractionation ε53Cr of -1.33 ‰, highlighting that Cr stable isotopes can effectively be used as an indicator of biochar-Cr reactions.

Polyamide 6 Recycled Fishing Nets Modified with Biochar Fillers: an Effort Toward Sustainability and Circularity

In a further research effort toward sustainability and circularity, this work demonstrates the possibility of designing and producing novel blends derived from recycled polyamide 6 (PA6) fishing net, incorporating two biochars, i.e., carbonaceous materials obtained from the controlled pyrolysis of vegetable biomasses, at different loadings (namely 5, 10, and 15wt.%). The biochar derived from lignocellulosic biomass enhanced both the mechanical properties and moisture resistance of the recycled polyamide, increasing the elastic modulus from 2.6 to 4.5GPa and reducing water uptake from 3.6 to 1.8%. Interestingly, thanks to its high silica content, the biochar derived from rice husk accounted for an increase in the activation energy for combustion of the polymer matrix (from 43.6 to 70.9kJ/mol). However, it also showed a detrimental effect on the water uptake and the mechanical behaviour of the blends. Besides, the possibility of replacing up to 15wt.% of petroleum-derived carbon black pigments with the biochars decreased the overall cost of PA6 blends. Also considering the biochar densities that are lower than those of traditional carbon fillers, the proposed blends may pave the way for the design, development, and exploitation of novel sustainable materials suitable for lightweight applications.

Acetate Shock Loads Enhance CO Uptake Rates of Anaerobic Microbiomes.

Pyrolysis of lignocellulosic biomass commonly produces syngas, a mixture of gases such as CO, CO2 and H2, as well as an aqueous solution generally rich in organic acids such as acetate. In this study, we evaluated the impact of increasing acetate shock loads during syngas co-fermentation with anaerobic microbiomes at different pH levels (6.7 and 5.5) and temperatures (37°C and 55°C) by assessing substrates consumption, metabolites production and microbial community composition. The anaerobic microbiomes revealed to be remarkably resilient and were capable of converting syngas even at high acetate concentrations of up to 64 g/L and pH 5.5. Modifying process parameters and acetate loads resulted in a shift of the product spectrum and microbiota composition. Specifically, a pH of 6.7 promoted methanogens such as Methanosarcina, whereas lowering the pH to 5.5 with lower acetate loads promoted the enrichment of syntrophic acetate oxidisers such as Syntrophaceticus, alongside hydrogenotrophic methanogens. Increasing acetate loads intensified the toxicity of undissociated acetic acid, thereby inhibiting methanogenic activity. Under non-methanogenic conditions, high acetate concentrations suppressed acetogenesis in favour of hydrogenogenesis and the production of various carboxylates, including valerate, with product profiles and production rates being contingent upon temperature. A possible candidate for valerate production was identified in Oscillibacter. Across all tested conditions, acetate supplementation provided additional carbon and energy to the mixed cultures and consistently increased carboxydotrophic conversion rates up to about 20-fold observed at pH 5.5, 55°C and 48 g/L acetate compared to control experiments. Species of Methanobacterium, Methanosarcina and Methanothermobacter may have been involved in CO biomethanation. Under non-methanogenic conditions, the bacterial species responsible for CO conversion remain unclear. These results offer promise for integrating process streams, such as syngas and wastewater, as substrates for mixed culture fermentation allowing for enhanced resource circularity, mitigation of environmental impacts and decreased dependence on fossil fuels.

Experiment investigation and multiscale modeling of biomass oxidative fast pyrolysis in a fluidized bed reactor

Experiments were conducted in a fluidized bed reactor to study the oxidative fast pyrolysis of biomass. The pressure drops along the bed height were measured, and the yield and composition of gas, liquid, and solid products were analyzed at various O2 concentrations. It was found that with the increase in oxygen concentration, the yield of biogas increased, especially CO2 and CO, while yields of bio-oil and biochar decreased. Under oxidative conditions, the fraction of tar in bio-oil was significantly reduced. A multiscale model was developed in the open-source code MFiX by integrating the reactor model based on the coarse-grained DEM-CFD, the intraparticle model, and the biomass oxidative fast pyrolysis kinetics. The model was verified by comparison with experimental data. As the oxygen concentration increases, the mixing and separation of biomass particles decreases, the residence time increases, the axial distribution moves upward, and the Lacey mixing index decreases. This study established experimental and theoretical foundations for designing and scaling up oxidative fast pyrolysis of biomass in fluidized beds.

The mechanism of plasma affecting biomass pyrolysis to more H2, activated char and less CO2

The mechanism of plasma affecting biomass pyrolysis to more H2, activated char and less CO2

Exergy, exergoeconomic and carbon emission analysis of a novel biomass pyrolysis system with self-heating and torrefaction

Exergy, exergoeconomic and carbon emission analysis of a novel biomass pyrolysis system with self-heating and torrefaction

Biomass pyrolysis for biochar production: Study of kinetics parameters and effect of temperature on biochar yield and its physicochemical properties

Biomass pyrolysis for biochar production: Study of kinetics parameters and effect of temperature on biochar yield and its physicochemical properties

Rethinking Biochar’s MRV Systems: A Perspective on Incorporating Agronomic and Organic Chemistry Indicators

Biochar, produced through the pyrolysis of biomass and green waste, offers significant potential as a soil amendment to enhance soil health and sustainability in agriculture. However, the current Measurement, Reporting, and Verification (MRV) systems for biochar predominantly focus on carbon credits/offsets, neglecting crucial aspects related to its usability and suitability as a soil amendment on agricultural fields. Through an examination of recent findings, this perspective explores the integration of geochemical tracers, functional group (hydroxyl, carboxyl, phenolic, lactonic, etc.) analysis, and nutrient dynamics into MRV procedures/systems to create a more comprehensive framework. By examining the applicability of these indicators, this paper identifies key gaps and proposes a more robust MRV approach. Such a system would not only facilitate better assessment of biochar’s agronomic benefits but also guide its optimal use in various soil types and agricultural practices.

Population genomics of a thermophilic cyanobacterium revealed divergence at subspecies level and possible adaptation genes

BackgroundCyanobacteria are diverse phototrophic microbes with ecological importance and potential for biotechnology applications. One species of thermophilic cyanobacteria, Thermosynechococcus taiwanensis, has been studied for biomass pyrolysis, estrogen degradation, and the production of bioethanol, monosaccharide, and phycocyanin. To better understand the diversity and evolution of this species, we sampled across different regions in Taiwan for strain isolation and genomic analysis.ResultsA total of 27 novel strains were isolated from nine of the 12 hot springs sampled and subjected to whole genome sequencing. Including strains studied previously, our genomic analyses encompassed 32 strains from 11 hot springs. Genome sizes among these strains ranged from 2.64 to 2.70 Mb, with an average of 2.66 Mb. Annotation revealed between 2465 and 2576 protein-coding genes per genome, averaging 2537 genes. Core-genome phylogeny, gene flow estimates, and overall gene content divergence consistently supported the within-species divergence into two major populations. While isolation by distance partially explained the within-population divergence, the factors driving divergence between populations remain unclear. Nevertheless, this species likely has a closed pan-genome comprising approximately 3030 genes, with our sampling providing sufficient coverage of its genomic diversity. To investigate the divergence and potential adaptations, we identified genomic regions with significantly lower nucleotide diversity, indicating loci that may have undergone selective sweeps within each population. We identified 149 and 289 genes within these regions in populations A and B, respectively. Only 16 genes were common to both populations, suggesting that selective sweeps primarily targeted different genes in the two populations. Key genes related to functions such as photosynthesis, motility, and ion transport were highlighted.ConclusionsThis work provides a population genomics perspective on a hot spring cyanobacterial species in Taiwan. Beyond advancing our understanding of microbial genomics and evolution, the strains collected and genome sequences generated in this work provide valuable materials for future development and utilization of biological resources.

Design and construction of low-cost biomass pyrolysis reactor for research and teaching in universities and colleges

Design and construction of low-cost biomass pyrolysis reactor for research and teaching in universities and colleges

Insights into the interactions between cellulose and hemicellulose during pyrolysis for optimizing the properties of biochar as a potential energy vector

Cellulose and hemicellulose, the main components of biomass, undergo noticeable interactions during biomass pyrolysis. In this study, biochar was produced by the co-pyrolysis of cellulose and hemicellulose. Three co-pyrolysis parameters, namely, pyrolysis temperature (400–800 °C), residence time (5–30 min), and percentage of cellulose (0–100 %), were investigated to optimize the properties of biochar, including the application of response surface methodology in the experimental study. The analysis revealed that co-pyrolysis interactions could improve the biochar yield by up to 41.37 % (567.74 °C, 19.52 min, 50 % cellulose percentage). The co-pyrolysis interactions specifically enhanced the fixed carbon content, elemental carbon content, and higher heating value of the biochar, with the most significant enhancements being 0.87 %, 3.60 %, and 3.85 %, respectively, while simultaneously decreasing the volatile content, [H]/[C] ratio, and [O]/[C] ratio of the biochar, with the most significant reductions of −9.30 %, −10.81 %, and −26.71 %. Based on the observed decrease in the intensity ratio of the D-band and G-band of biochar in the Raman spectra, greater co-pyrolysis interactions increased the graphitization degree of the biochar. The analysis of X-ray photoelectron spectroscopy (XPS) investigations revealed that the interactions enhanced the contents of the C-C, C-O/C-O-C, aromatic, and OH functionalities while reducing the number of COO-, COOH, and CO functional groups. The results of this work indicate that the co-pyrolysis interaction between cellulose and hemicellulose contributes to optimizing the properties of biochar as a potential energy vector.

Synergistic effects of iron with alkali and alkaline earth metals on catalytic pyrolysis of biomass for highly graphitized carbon

To prepare highly graphitized carbon from biomass and understand the synergistic effects of iron with alkali and alkaline earth metals (AAEMs), K and Ca were introduced to iron-catalyzed graphitization of biomass. Results showed that both K and Ca accelerated the thermal decomposition rate of biomass, and the activation energy of the devolatilization stage with K and Ca reduced to 60.882 kJ/mol and 45.342 kJ/mol respectively, compared to 73.657 kJ/mol without K/Ca. The porous graphitic carbon obtained at 850 °C with the existence of K and Fe exhibited the highest graphitization degree parameter (g = 0.5193) with a big surface area (170.504 m2/g). The carbon with Ca and Fe showed a developed mesoporous structure (198.979 m2/g) and high graphitization parameter (g = 0.1783), compared to g = 0.0934 without K and Ca. Finally, the tailor-catalyzed mechanism of iron-catalyzed graphitization of biomass in the presence of K/Ca was proposed. K reduced the sp3 amorphous carbon structures and intercalated carbon framework while Ca produced the in-situ CaO template and extra gasification gas of CO2, resulting in an acceleration of the graphitization of biomass.

Thermal degradation of 18 amino acids during pyrolytic processes

Biomass pyrolysis greatly impacts climates, ecosystem dynamics, air quality, human health, global carbon and nitrogen cycle. The emissions of nitrogen-containing compounds from biomass pyrolysis highly depend on the protein nitrogen existing in biomass. However, the quantitative kinetic information, including the rate constant and apparent activation energy of individual amino acid induced by pyrolysis are still yet to be well-constrained. Towards this, we performed a series of controlled pyrolysis experiments where 18 equimolar free amino acids standard mixtures were pyrolyzed under ambient oxygen at temperatures between 160 and 240 °C. Additionally, straw samples were pyrolyzed to understand the mechanism of combined amino acids in protein liberation to free amino acids during pyrolytic processes. Our observations indicated that an increase in heating duration and temperature promote the degradation of free amino acids. Further, the heating stability of the 18 examined amino acids varied, which could be related to the length and functional groups present in their side chains. Our result shows that the degradation processes of all examined 18 amino acids followed irreversible first-order reaction kinetics in air within the given temperature range, with their activation energy ranging from 88.5 to 137.44 kJ mol−1. The distinct distribution patterns of both combined and free amino acids in aerosol samples from straw pyrolytic processes were obtained. The kinetic information of amino acids garnered herein helps to elucidate the transformation mechanisms of nitrogenous compounds during biomass burning.

Enhanced physicochemical properties of Himalayan Weeping Bamboo-biochar for rapid multicomponent textile dyes uptake under classical and ultrasound irradiation: A comparative study

This study focused on synthesizing a low-cost adsorbent via a unique two-step solvothermal slow pyrolysis of Drepanostachyum falcatum plant biomass. It evaluated its adsorption capabilities for removing various textile dyes, including methylene blue (MB), basic fuchsin (BF), and methyl orange (MO), from aqueous solutions. Under conventional and ultrasound-assisted conditions, the adsorption performance was assessed for single, binary, and ternary dye systems. Comprehensive investigations examined the effects of environmental factors such as temperature, pH, humic acid, and interfering ions on adsorption. The findings revealed that ultrasonication significantly accelerated the adsorption process, making it up to six times faster than classical adsorption methods, and equilibrium was reached in one-tenth the time required without ultrasound. The experimental data best fit the pseudo-second-order kinetics model, indicating that chemisorption was the dominant adsorption mechanism. Additionally, the Freundlich isotherm suggested multilayer sorption on the biochar surface. Maximum adsorption capacities under ultrasound were found to be 139.34 mg/g for MB, 75.09 mg/g for MO, and 98.13 mg/g for BF dyes, with a higher affinity observed for cationic dyes compared to anionic dyes. The study provides insights into an efficient, novel synthesis method for converting waste biomass into a valuable adsorbent for dye removal. It also highlights the role of ultrasound in enhancing physicochemical properties, facilitating improved mass transfer, and promoting better interaction between the dyes and the adsorbent.

Mechanistic insights into adsorption-desorption of PFOA on biochars: Effects of biomass feedstock and pyrolysis temperature, and implication of desorption hysteresis

Adsorptive removal of the emerging organic pollutant perfluorooctanoic acid (PFOA) from contaminated water using biochar is a promising cost-effective approach. To determine the stability of PFOA adsorption on biochar, the thermodynamic analysis of the adsorption-desorption behavior is essential. This study comprehensively investigated the adsorption and desorption of PFOA on biochars derived from maple sawdust, peanut shells and corn stalks, pyrolyzed at peak temperatures of 400, 600 and 800 °C. The findings indicated that the micropore volume of the biochars was key to PFOA adsorption, with peanut shell biochar produced at 800 °C showing the highest adsorption capacity of 16.75 mg/g, attributed to its larger micropore volume (0.22 m3/g). Thermodynamic analysis showed that the negative values of ∆G0 of PFOA adsorption ranged from −2.24 to −5.38 kJ/mol, confirmed that the process was spontaneous and involved physical pore-filling. However, the close similarity between the adsorption and desorption isotherms, coupled with a low hysteresis coefficient, clarified that the PFOA adsorption was unstable and prone to desorption. The thermodynamic insights from this study highlighted that lignin-rich biochar produced at high temperature with high micropore content was very favorable for the effective adsorptive removal of PFOA, while the long-term adsorption stability should not be overlooked in the remediation applications.

Pyrolysis and beyond: Sustainable valorization of plastic waste

The recycling of plastics through pyrolysis has garnered significant attention as a waste management approach, particularly given upcoming regulations and the urgent need for absolute sustainability. This review paper evaluates pyrolysis's technological, environmental, and regulatory aspects, emphasizing the need to prioritize environmental impact over purely economic considerations. While it is recognized that financial challenges have constrained many past attempts at scaling pyrolysis systems, this paper argues that a shift in focus toward sustainability criteria is essential for the technology's long-term viability. Prioritizing environmental outcomes is critical given the pressing issues like plastic pollution, which presents significant threats to ecosystems and human health. A comprehensive assessment of environmental impacts is vital for technologies intended for large-scale deployment, ensuring that they align with global sustainability goals. This perspective is especially pertinent in light of the current United Nations Environment Programme (UNEP) global plastic pollution treaty negotiations, where there is a contentious debate over the true circularity of chemical recycling. Environmentalists and several nations advocate for significant reductions in plastic production and bans on single-use plastics. At the same time, oil-producing countries and petrochemical companies push for circularity in the plastic economy. The paper explores the promise and limitations of pyrolysis technology for valorizing plastic wastes, comparing its efficacy with other waste management methods. Biomass pyrolysis is discussed due to its significant synergies with plastic pyrolysis and its potential for carbon sequestration through biochar. However, the discussion on biomass pyrolysis is limited in scope, with the paper's primary focus on waste plastic pyrolysis. The paper discusses the challenges and opportunities in utilizing pyrolysis for waste plastics, which are considered along with regulatory and geopolitical aspects. Environmental impacts, including life cycle analysis and planetary boundary considerations, are examined to understand why pyrolysis has yet to achieve widespread adoption. A case study on Plastic Energy, SABIC, and Unilever highlights current industry status, technological advancements, and information gaps. Finally, a comprehensive framework is proposed to achieve net-zero emissions, improve air quality, and ensure absolute environmental sustainability in plastic recycling. Recommendations are provided for the plastic industry and research institutions to support the transition towards sustainable waste management practices.