This study evaluates the influence of pyrolysis conditions and CO₂ physical activation on the Cd2⁺ adsorption performance of biochars derived from cocoa pod hulls. Biochars were produced at 400, 650, and 900 °C, and a fraction of the biochar obtained at 900 °C was physically activated under CO₂ at 800 °C for 1 h. A commercial activated carbon (B-Pure® 10-NB, DESOTEC) was used as a benchmark material. Adsorption kinetics and isotherms were analyzed using standard models with corresponding statistical indicators (R2). The results show that Cd2⁺ removal performance strongly depends on surface chemical properties rather than textural properties such as surface area. The biochar produced at 400 °C exhibited the highest performance (Langmuir adsorption capacity = 23.58 mg.g⁻1, R2 = 0.99, Qmax/SBET = 7.93 mg.m⁻2), mainly governed by complexation and ion exchange mechanisms. In comparison, lower performances were obtained for biochars produced at 650 °C (9.78 mg.g⁻1, R2 = 0.98, Qmax/SBET = 1.96 mg.m⁻2) and 900 °C (10.28 mg.g⁻1, R2 = 0.98, Qmax/SBET = 3.43 mg.m⁻2), the activated biochar (10.19 mg.g⁻1, R2 = 0.99, Qmax/SBET = 0.057 mg.m⁻2), and the commercial activated carbon (2.28 mg.g⁻1, R2 = 0.97, Qmax/SBET = 0.0028 mg.m⁻2), where ion exchange predominates. Despite its high surface area, commercial activated carbon showed the lowest normalized adsorption capacity, confirming that adsorption efficiency is not directly proportional to surface area. Under the specific experimental conditions (a single CO₂ activation condition at 800 °C for 1 h; adsorption: 50 mg adsorbent, 50 mL Cd2⁺ solution at 2–10 mg.L−1, pH = 6.0 ± 0.05, 150 rpm, 48 h, 22 ± 1 °C), physical activation did not improve Cd2⁺ adsorption performance. These findings highlight the key role of surface chemistry and mineral content and demonstrate that low-temperature biochar can be an efficient and low-cost adsorbent.

This study presents the characterization of an innovative simple and low-cost staged combustion reactor designed for cashew nut shells (CNS), with the aim of optimizing their energy recovery for productive applications. A comprehensive experimental campaign was conducted to evaluate the performance of the pilot unit installed at the BioWooEB platform of CIRAD. Additional tests were carried out on a less instrumented prototype operating under industrial conditions in Bobo-Dioulasso. The pilot tests revealed moderate thermal efficiency, below 50 %, due to operational constraints. The presence of flow meters introduced pressure drops and disrupted airflow distribution-particularly between Air 1 and Air 2-leading to a misinterpretation of the reaction regime. This caused a reduction in the calorific value of the produced gases and decreased the overall system efficiency. Despite these limitations, the pilot exhibited satisfactory environmental performance, with minimal pollutant emissions. In contrast, the prototype achieved higher thermal efficiency (>= 60 %), attributed to improved airflow management and the absence of flow meters, which allowed for a more homogeneous distribution of air. This resulted in slower solid bed movement, higher reactor temperatures (up to 800 degrees C), and enhanced conversion of CNS into high-energy syngas. However, challenges such as localized overheating and insufficient pressure persist, requiring further optimization. Addressing these technical barriers could substantially improve CNS combustion performance, positioning this technology as a viable and cleaner alternative to fossil fuels for energy generation in small and medium-sized agro-industrial enterprises in West Africa.

Cashew nut shell (CNS) is an abundant agro-industrial residue characterized by a high content of solvent-extractives compounds, which strongly influences its thermal conversion behavior and the nature of pyrolysis products. In this study, two complementary questions were addressed using a combined experimental strategy that integrated sequential Soxhlet extraction, multi-scale thermogravimetric analysis, and product quantification. CNS was sequentially extracted with hexane, acetone, and water to remove extractives of increasing polarity extractives and generate solid residues of increasing lignocellulosic character. The thermal behavior of raw CNS was investigated under near-intrinsic conditions by micro-TGA using small sample masses, and under macro-scale conditions using whole shells and packed beds of milled CNS to analyze heat- and mass-transfer limitations. Non-condensable gases were quantified using µ-GC, while condensable products were quantified by GC–MS/MS together with water determination. The results show that sequential extraction recovered about 69 wt.% of the initial CNS mass as extractives and altered pyrolysis pathways. Under near-intrinsic conditions, the DTG profile of raw CNS was described by eight Gaussian pseudo-components with R² > 0.988, indicating a multi-step devolatilization pattern. At the gram scale, decomposition peaks broadened, shifted to higher temperatures, and overlapped, indicating transport limitations associated with sample organization. Product quantification showed that extractive removal shifted the condensable fraction from phenolic- and aromatic-rich compositions toward higher formation of acids, furans, sugars, and water, while H₂ formation increased in the gas phase. Overall, these results establish a quantitative relationship between extractive removal, thermal decomposition behavior, and pyrolysis product distribution, and provide a basis for the valorization of CNS in integrated biorefinery applications.

The objective of this study is to convert agricultural residues, particularly cocoa pod shells from the Ivory Coast, into low-cost bioadsorbents. In this context, biochar can be produced from agricultural residues for use in removing water pollutants. The main question was whether the adsorption efficiency of biochar produced from this biomass can be improved by physical activation with carbon dioxide (CO₂). To this end, an assessment was made of the effectiveness of raw and activated biochar in adsorbing cadmium (Cd2⁺) from an aqueous solution under conditions close to those of drinking water (pH = 6 and temperature = 22 ± 1 °C). The results of the adsorption indicated that raw biochar, obtained by pyrolysis of cocoa pod shell biomass at 400°C, was more effective at removing Cd2⁺ (removal rate = 72.0 ± 1.1% and adsorption capacity = 14.4 ± 0.3 mg/g) than activated biochar, which was produced by pyrolysis of the same biomass at 900°C followed by activation with CO₂ at 800°C (removal rate = 65.3 ± 1.8% and adsorption capacity = 13.0 ± 0.4 mg/g). The experiment indicates that the chemical surface properties of adsorbents significantly influence the adsorption of Cd2⁺, while physical properties have a minor impact. This study revealed that raw biochar pyrolysed at 400 °C was more efficient than activated biochar in adsorbing Cd2⁺, thus offering an easily available, environmentally friendly, and inexpensive adsorbent for improving drinking water quality. Therefore, it is not systematically necessary to activate biochar to be effective in removing pollutants from water.

Cleaning syngas, particularly reforming tars, is still a major bottleneck to the development of gasification. In this work, syngas was simultaneously sampled and analysed downstream and upstream of a tar conversion reactor using a real syngas produced with a commercial gasifier. At 800 degrees C and 2 s residence time, tar conversion reached 51a% compared with only 11 % in an inert bed. The tar content in the syngas decreased from 8.1 to 4.2 g/Nm3. Almost all the tertiary tars were converted, and only benzene, toluene, and naphthalene persisted. The energy content of the syngas increased by 5 % thanks to simultaneously increase of the LHV and syngas flowrate. LHV's increase in mainly due to H2 production.

Slow pyrolysis can be used to convert residual agricultural biomass into energy-dense biochar along with its by-product, pyrolysis liquid, for diverse applications. Due to its high concentration of bioactive chemicals, pyrolysis liquid has gained interest as a potential wood protectant. This study aims to evaluate the efficacy of slow pyrolysis liquid from sugarcane bagasse (Saccharum spp.) for wood protection against fungi and termites and its water-leaching properties. Pyrolysis liquid was obtained from slow pyrolysis at a temperature of 500 °C, a heating rate of 10 °C/min, and a holding time of 60 min. Specimens of European beech wood (Fagus sylvatica) and Scots pine sapwood (Pinus sylvestris) were impregnated with pyrolysis liquid using different concentrations and dried at different drying temperatures. A higher drying temperature (103 °C) was found to promote the agglomeration of pyrolysis liquid inside wood cells and lower the leaching rate. Pyrolysis liquid was effective against termites (Reticulitermes flavipes) as a repellent and toxic agent at a concentration of 25

Engineering LB powdered fuel via fine comminution and torrefaction processes.

This study investigates the synergistic behavior between oxidative atmosphere and potassium catalytic effects on woody (Amapai) and non-woody (Miscanthus) biomass. Inert and oxygen-lean torrefaction was conducted at 275 & DEG;C for demineralized and K-loaded samples in fixed-bed and thermo-gravimetric equipment. Torrefaction improvement was assessed by torrefaction severity index (TSI), Catalytic Enhancement Area (CEA), Catalytic index (CI), and conversion rate (CR). Gas chromatography-mass spectrometry analyzed the impact on condensable compounds. The K% anticipated the biomass oxidation and the oxidative medium improved the catalytic effect. CEA and CI provided a reliable performance index (R-2 > 0.90) to assess the synergistic effect. Condensable compound yields variation with increasing K% was similar for both atmospheres but the K-impact on the compounds production was intensified under oxidative conditions. The furfuryl alcohol yield increased by a factor of 30 for Amapai comparing higher K% and demineralized samples, whereas a factor of 3 was observed for inert conditions. For Miscanthus, the factors of increasing production were 22 and 5 for oxidative and inert atmosphere. Under oxygen-lean, syringaldehyde and vanillin yields decreased with higher K%, whereas inert treatment revealed insignificant effects. The results indicate that torrefaction duration and targeted condensates production could be improved according to the K% and atmosphere.(C) 2022 Published by Elsevier Ltd.

Self-heating and spontaneous combustion of torrefied biomass are direct hazards related to the production, storage and transport of torrefied biomass. In this study, we investigated the effect of combined air oxidation and water sorption on self-heating of torrefied agricultural residue biomass at 60, 120 and 180 ??C cooling temperatures by measuring weight change and heat flow using thermogravimetric analysis and differential scanning calorimetry (TGA/DSC). Our results showed that the effect of water adsorption predominated at 60 ??C. When the gas stream was changed from nitrogen to humid nitrogen, the weight of the torrefied biomass increased rapidly associated with heat generation. Conversely, at 180 ??C, the effect of air oxidation predominated and the torrefied biomass decreased rapidly when it was exposed to dry air associated with heat generation. The effect of water adsorption decreased with an increase in the cooling temperature whereas the effect of air oxidation increased with an increase in temperature. The higher torrefaction severity increases the self-heating propensity. The air oxidation and water adsorption may lead to the self-heating of torrefied biomass.

To assess the potassium catalytic influence on the kinetic behavior of non-oxidative biomass torrefaction, two woody biomass samples (Amapai and Eucalyptus), as well as Miscanthus samples impregnated with three different K2CO3 concentrations (0.003 M, 0.006 M, and 0.009 M) were comprehensively studied. The solid thermal degradation kinetics were analyzed through thermogravimetric analysis in usual torrefaction conditions (275 degrees C during 68min and 10 degrees C.min(-l) heating rate) and an original Potassium Responsive Numerical Path (PRNP). Therefore, a two-step reaction model with unified activation energies was integrated within a numerical method that considers the torrefaction severity influence for each potassium-loading content in all three biomasses. The proposed PRNP enables an accurate solid yield prediction (R-2 > 0.9995). A strong (R-2 between 0.91 and 0.99) and a significant (p <= 0.0463) linear correlation was highlighted between the potassium content in biomass, the increasing reaction rates, and pre-exponential factors. The solid and volatile product distribution depicted faster and marked degradation for solid pseudo-components and anticipated a higher volatile release. The catalytic torrefaction severity factor determination enabled correlating treatment severity and kinetic rates showing better correlations than K% for wood biomass. The accurate results are conducive to developing numerical models that are essential for assessing solid fuel upgrading under catalytic effect in torrefaction plants. (C) 2021 Elsevier Ltd. All rights reserved.

Biomass potassium impregnation is used to increase thermal degradation by catalytically influencing the wood components' conversion mechanisms during torrefaction. Chemical composition of the biomass, including potassium content and process temperature and time, appear as (catalytic or not) torrefaction parameters that impact weight loss, which can be considered performance indicators. The literature on torrefaction reports process performance evaluation by defining severity indexes. Evaluating the torrefaction performance by indexes provides valuable and dimensionless data as input in numerical modeling for up-scaling the analysis of production systems and assessing environmental products and processes. Nevertheless, no study presents an assessment of the torrefaction indexes correlating the potassium catalytic effects with the operating parameters (temperature and time) and the feedstock sensitivity, simultaneously. Therefore, this study examines the effect of biomass potassium impregnation on weight loss kinetics, employing different indexes such as the torrefaction severity index (TSI), the torrefaction catalytic effect index (TCEI), the catalytic index (CI) and modified torrefaction severity factor (TSFmod) to quantify the catalysis on torrefaction. Two hardwoods, Amapai (Brosimum potabile Ducke) and Eucalyptus (Eucalyptus urophylla x E. camaldulensis), were demineralized and impregnated with different K2CO3 concentrations and then torrefied at 275 degrees C for 80 min. The process results enabled the assessment of the accuracy of the correlation between the indexes and the non-condensable volatile release during catalytic torrefaction. The TCEI provided the identification of two catalytic enhancement regions marked by 15 and 17 min holding time for Amapai and Eucalyptus. The CI and TSFmod presented R2 >= 0.97 when validated against the TSI, supporting their accuracy as a performance indicator. The correlation between indexes and noncondensable gases presented significance for 88% of the evaluated cases. The results of the TSI, TCEI and CI indexes as performance indicators are conducive to quantifying the catalytic level for torrefaction operation, reactor design, and production of added-value biofuels.

Sugarcane bagasse was pyrolyzed using a laboratory fixed bed reactor to produce char and its by-product (pyrolysis liquid). The pyrolysis experiments were carried out using different temperatures (400 degrees C and 500 degrees C), heating rate (1 degrees C/min and 10 degrees C/min), and holding time (30 min and 60 min). Char was characterized according to its thermal properties, while the pyrolysis liquid was tested for its anti-fungal and anti-termite activities. Pyrolysis temperature and heating rate had a significant influence on the char properties and the yield of char and pyrolysis liquid, where a high-quality char and high yield of pyrolysis liquid can be obtained at a temperature of 500 degrees C and a heating rate of 10 degrees C/min. The yield of char and pyrolysis liquid was 28.97% and 55.46%, respectively. The principal compounds of pyrolysis liquid were water, acetic acid, glycolaldehyde, 1-hydroxy-2-propanone, methanol, formic acid, levoglucosan, furfural, followed by some phenol compounds and guaiacol derivatives. Pyrolysis liquid at a concentration of 0.20% and 0.25% (v/v) caused a 100% inhibition of Coniophora puteana and Trametes versicolor, respectively, when performing inhibition growth tests in Petri dishes. Filter paper treated with 10% of pyrolysis liquid caused 100% of termite mortality, while only 5.65%-7.03% of the treated filter papers consumed by termites at such concentration. Pyrolysis liquid is potentially effective to be used in the formulation of wood protection against fungi and termites.

Combustion experiments of raw and torrefied pine and demolition wood particles (600-800 mu m) are performed at 800 degrees C in a drop tube furnace. The results provide the oxygen and carbon monoxide profiles along the reactor axis. These data are then used in a numerical model, developed to determine the kinetic parameters of devolatilisation and oxidation of the pulverized biomasses. In order to simulate the gas phase reactions, the model also takes as input the composition of the volatiles of the tested fuels measured during pyrolysis experiments at 800 degrees C in the drop tube furnace. The model adopts different scenarios of particle volume evolution and different drag coefficient models in order to test their influence on the derived kinetic parameters. One of the volume evolution scenarios is a specific sub-model obtained by optical diagnostics of the combustion of the three biomasses in a previous study. Four other volume sub-models found in literature are also tested. For each of these scenarios, the model estimates close activation energy for devolatilization with a maximum variation of 2 kJ.mol(-1) from one scenario to another, while the activation energy of char oxidation is more influenced, varying by 14 kJ.mol(-1) with different scenarios. The five scenarios show similar gas concentrations and burnout versus the distance travelled by the particle. Nevertheless, this gives rise to a noticeable difference in the particle temperature along the furnace axis (+/- 100 degrees C at some positions), in addition to different particle velocity and residence time (similar to +/- 10%). The influence of the drag force is also studied using enhanced non-spherical model versus a spherical model. The non-spherical model leads to 10 to 14 kJ.mol(-1) higher devolatilisation activation energies and 10 to 19 kJ.mol(-1) higher char oxidation activation energies than the spherical model, along with a better prediction of the CO levels.

When biomass is thermally treated, the enrichment of carbon in the remaining "green coal" is correlated with the temperature and duration. Other properties related to the energetic properties of the torrefied biomass are closely related to chemical modifications and correlated to the material mass loss occurring during the thermal degradation. The possibility of using near infrared spectrometry has been investigated to predict the mass loss ofPinus sylvestriswood torrefied at temperatures ranging from 220 degrees C to 300 degrees C with durations varying from 1 minute to 10 hours. A first mass loss prediction model (NIR-260) associated with the mean torrefaction temperature of 260 degrees C was developed, and appeared suitable only for this temperature due to specific chemical reactions rate. A second model (NIRS-All), using all available data was constructed and showed an accurate mass loss prediction, for both low (220 degrees C) and high temperatures (300 degrees C). The main differences between NIRS-260 and NIRS-All models are mainly attributed to the thermal modification of hemicelluloses and cellulose fractions occurred during the wood torrefaction. The results showed near infrared spectrometry combined with multivariate calibration modeling have potential utility in an industrial context as a standardized continuous method to figure out the mass loss of biomass during torrefaction by a rapid characterization. Novelty Statement The novelty concerns the use of the Near Infrared Spectrometry (NIRS) combined with multivariate calibration modeling as a standardized method for determining the mass loss biomass during torrefaction by a rapid and nondestructive characterization. A model was constructed and showed an accurate mass loss prediction, for both low (220 degrees C) and high temperatures (300 degrees C). Near infrared spectrometry have potential utility in an industrial context as a standardized continuous method.

Performance of wood gasification genset is sensitive to the moisture content in the feedstock and the electrical load (demand of users). This study investigates the influence of these process parameters on the electrical efficiency of the genset (eta(global)), the electrical engine efficiency (eta(engine)), the cold gas efficiency (CGE), and the syngas composition. Experimental tests were carried out by varying the moisture content from 11% to 23% and the electrical power from 4.7 kW to 12.8 kW on a commercial gasifier equipped with precise measuring tools. The increase of the performance when the electrical load is increased or when the moisture content in the wood chips is decreased is both quantified and discussed. Such behaviour was mainly explained by differences in engine filling rates and reactor temperatures. (C) 2020 Elsevier Ltd. All rights reserved.

This research focused on the Energy valorization of lignocellulosic products and their by-products for the protection of bio-materials, is dedicated to the valorization of the sugar cane bagasse from Reunion Island (Oversea territory, France), a region where the sugar industry plays an important role in the agricultural sector. The objectives of this research were to: (i) characterize the biochar and the bio-oil according to the pyrolysis process parameter and the biomass used, and to (ii) evaluate the potential of said bio-oil as wood preservatives. Pyrolysis of bagasse was conducted using an experimental set up of fixed bed reactor. Various temperatures (T = 400 °C, 500 °C) and holding time th (30 and 60 minutes), and a heating rate of 10°C/minutes were applied. Pyrolysis products, consisting of biochar and bio-oil, were recovered for further analysis. The biochars were characterized for their proximate and ultimate analysis for energy valorization. For evaluating the anti fungal efficacy of the recovered bio-oil, we conducted fungal growth inhibition tests against two types of wood-decaying fungi: Coriolus versicolor (white-rot) and Coniophora puteana (brown-rot) on Petri dishes, as well as decay tests on treated wood samples.

The aim of this study is to investigate the reduction of tar produced during biomass pyrolysis by torrefaction pretreatment. In this study, various biomass feedstocks (pine, ash wood, miscanthus, and wheat straw) with different particle sizes were torrefied at 280 °C. The results indicated that both particle size and biomass composition have a significant effect on the yield and properties of the torrefied products. With increasing particle size, the yield of solid product increased, while the yield of condensable liquid and noncondensable gases decreased. The raw biomasses and torrefied biomasses were then subjected to pyrolysis at 500 °C. The results clearly showed that torrefaction had a significant effect on the yield and composition of tar generated during subsequent pyrolysis. For all biomasses, the tar yields of biomasses after torrefaction were 42–62% lower compared to direct pyrolysis of raw biomasses. However, when considering the condensable liquid produced combining torrefaction and pyrolysis, the total yield of condensable liquid produced decreased 3–12% compared to the direct pyrolysis. This suggests that not only some volatiles were released during the torrefaction process, but the thermal pretreatment also transformed the biomass structure to less favor tar production in subsequent pyrolysis step.