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Sodium-ion batteries (SIBs) serve as the most promising next-generation commercial batteries besides lithium-ion batteries (LIBs). Hard carbon (HC) from renewable biomass resources is the most commonly used anode material in SIBs. In this contribution, we present a review of the latest progress in the conversion of waste biomass to HC materials, and highlight their application in SIBs. Specifically, the following topics are discussed in the review: (1) the mechanism of sodium-ion storage in HC, (2) the HC precursor's sources, (3) the processing methods and conditions of the HCs production, (4) the impact of the biomass types and carbonization temperature on the carbon structure, and (5) the effect of various carbon structures on electrochemical performance. Data from various publications have been analyzed to uncover the relationship between the processing conditions of biomass and the resulting structure of the final HC product, as well as its electrochemical performance. Our results indicate the existence of an ideal temperature range (around 1200 to 1400 °C) that enhances the formation of graphitic domains in the final HC anode and reduces the formation of open pores from the biomass precursor. This results in HC anodes with high storage capacity (>300 mAh/g) and high initial coulombic efficiency (ICE) (>80%). [ABSTRACT FROM AUTHOR]

Homogenous secondary pyrolysis is category of reactions following the primary pyrolysis and presumed important for fast pyrolysis. For the comprehensive chemistry and fluid dynamics, a probability density functional (PDF) approach is used; with a kinetic scheme comprising 134 species and 4169 reactions being implemented. With aid of acceleration techniques, most importantly Dimension Reduction, Chemistry Agglomeration and In-situ Tabulation (ISAT), a solution within reasonable time was obtained. More work is required; however, a solution for levoglucosan (C 6 H 10 O 5 ) being fed through the inlet with fluidizing gas at 500 °C, has been obtained. 88.6% of the levoglucosan remained non-decomposed, and 19 different decomposition product species were found above 0.01% by weight. A homogenous secondary pyrolysis scheme proposed can thus be implemented in a CFD environment and acceleration techniques can speed-up the calculation for application in engineering settings. [ABSTRACT FROM AUTHOR]

Abstract: To meet the urgent environmental targets, substituting coal with biomass has been considered to be an effective and promising method over the last decades. In this paper, a new concept of volumetric combustion is proposed and further developed to achieve 100% fuel switching to biomass in large scale coal-fired boilers. Volumetric combustion not only changes the in-furnace flow but also affects the combustion reactions by the intensive mixing and internal recirculation of the flue gases. Firstly, the volumetric combustion properties of the wood pellets were investigated experimentally. An Aspen model was then used to thermodynamically describe and study the volumetric combustion with three different types of fuel, and the emission properties of CO2 and NOx were compared. Finally, two applications of volumetric combustion were discussed. It is concluded that the wood pellets ignited and combusted much faster than the coal pellets and had a larger combustion volume when combusted under lower oxygen concentration conditions, and the ignition time was almost independent of the oxygen concentration when the oxidizer was preheated to 1000°C. In addition, the NOx emissions decreased as the recirculation ratio of the flue gas increased, and as the percentage of biomass used in co-firing increased, the amount of flue gas that needs to be recycled for reduction of NOx decreased. Thus, the volumetric combustion is beneficial as it reduces the operation cost of NOx reduction. The volumetric combustion would be an attractive technology for co-firing a large proportion of biomass in coal-fired boilers with high boiler efficiency and effective emissions reduction. [Copyright &y& Elsevier]

Abstract: Coconut and cashew nut shells are two typical biomass wastes abundant in most of the tropical countries. However, despite their enormous potential as energy sources, they are hardly studied and their thermal characteristics are still not well known. In this study, both biomasses are thermally degraded through thermogravimetry and their characteristics such as devolatilisation profiles and kinetics are analyzed, from 250 to 900 °C, in an inert atmosphere, at two different heating rates, and compared with wood pellets. The results show that their pyrolysis profiles are different from that of the commonly studied woody biomass. In fact, they present two different peaks instead of the one overlapping peak, for hemicellulose and cellulose. In addition, they present activation energies ranging from that are slightly above the commonly known maximum for biomass. At 10 and 20 °C/min the activation energy varied from about 130 to 174 and 180 to 216 kJ/mol, for cashew and coconut shells, respectively. [Copyright &y& Elsevier]

Hydrogen and biocarbon are important materials for the future fossil-free metallurgical industries in Sweden; thus, it is interesting to investigate the process that can simultaneously produce both. Process simulations of biomass pyrolysis coupled with steam reforming and water-gas-shift to produce H2, biocarbon, and bio-oil are investigated in this work. The process simulation is performed based on a biomass pyrolysis plant currently operating in Sweden. Two co-production schemes are proposed: (1) production of biocarbon and H2, and (2) production of biocarbon, H2, and bio-oil. Sensitivity analysis is also performed to investigate the performance of the production schemes under different operating parameters. The results indicated that there are no notable differences in terms of the thermal efficiency for both cases. Varying the bio-oil condenser temperature only slightly changes the system's thermal efficiency by less than 2%. On the other hand, an increase in biomass moisture content from 7 to 14 wt.% can decrease the system's efficiency from 79.0% to 72.6%. Operating expenses are evaluated to elucidate the economics of 3 different cases: (1) no bio-oil production, (2) bio-oil production with the condenser at 50 °C, and (3) bio-oil production with the condenser at 130 °C. Based on operation expenses (OPEX) and revenue alone, it is found that producing more bio-oil helps improving the economics of the process. However, capital costs and the cost for post-processing of bio-oil should also be considered in the future. The estimated minimum selling price for biocarbon based on OPEX alone is approx. 10 SEK, which is within the range of the current commercial price of charcoal and coke. [ABSTRACT FROM AUTHOR]

The present work is an attempt to optimize the proportion of H-ZSM-5 and Al-MCM-41 in the catalyst mixtures for lignocellulose biomass catalytic pyrolysis. The H-ZSM-5 proportions of 50.0, 66.7, 75.0, and 87.5 wt.% were examined for the upgrading of biomass pyrolysis vapors in the fixed bed reactor. The catalyst mixture of 87.5 wt.% H-ZSM-5 and 12.5 wt.% Al-MCM-41 was found most effective in this study, giving a 65.75% deoxygenation degree. An organic-rich bio-oil was obtained with 74.90 wt.% of carbon content, 8 wt.% of hydrogen content, 15 wt.% oxygen content, a 0.39 wt.% water content, and a high heating value of 34.15 MJ/kg. The highest amount of desirable compounds among the studied catalytic experiments, which include hydrocarbons, phenols, furans, and alcohols, was obtained with a value of 95.89%. A significant improvement in the quality of bio-oil with the utilization of H-ZSM-5 and Al-MCM-41 catalyst mixtures was the rise of desirable compounds in bio-oil. [ABSTRACT FROM AUTHOR]

The global Sustainable Development Goals highlight the necessity for affordable and clean energy, designated as SDG7. A sustainable and feasible biorefinery concept is proposed for the carbon-negative utilization of biomass waste for affordable H 2 and battery anode material production. Specifically, an innovative tandem biocarbon + NiAlO + biocarbon catalyst strategy is constructed to realize a complete reforming of biomass pyro-vapors into H 2 +CO (as a mixture). The solid residues from pyrolysis are upgraded into high-quality hard carbon (HCs), demonstrating potential as sodium ion battery (SIBs) anodes. The product, HC-1600-6h, exhibited great electrochemical performance when employed as (SIBs) anodes (full cell: 263 Wh/kg with ICE of 89%). Ultimately, a comprehensive process is designed, simulated, and evaluated. The process yields 75 kg H 2 , 169 kg HCs, and 891 kg captured CO 2 per ton of biomass achieving approx. 100% carbon and hydrogen utilization efficiencies. A life cycle assessment estimates a biomass valorization process with negative-emissions (−0.81 kg CO 2 /kg-biomass, reliant on Sweden wind electricity). A techno-economic assessment forecasts a notably profitable process capable of co-producing affordable H 2 and hard carbon battery anodes. The payback period of the process is projected to fall within two years, assuming reference prices of 13.7 €/kg for HCs and 5 €/kg for H 2. The process contributes to a novel business paradigm for sustainable and commercially viable biorefinery process, achieving carbon-negative valorization of biomass waste into affordable energy and materials. [Display omitted] • Fully valorization of biomass into hydrogen, battery anodes, and negative emission. • Tandem biocarbon + NiAlO + biocarbon catalyst reform pyro-vapors into H 2 -rich syngas. • High-performance SIB anodes with 263 Wh/kg of capacity and 89% of ICE. • A sustainable and profitable biorefinery realizing payback period within two years. [ABSTRACT FROM AUTHOR]

In order to eliminate problems such as corrosion and ash deposition caused by alkalis, effects of the biomass composition and the pressure of syngas in the downstream process on condensation of alkalis in a wood steam/oxygen blown fluidized bed gasification process are investigated based on a model. This model is established by combining Aspen Plus with SimuSage. Aspen Plus is applied to predict the composition of major gas species formed by C, H, O, N, S and Cl, using empirical correlations to predict the yields of non-equilibrium substances. SimuSage is used to study the release and condensation of inorganics associated with the minor elements (Al, Ca, Fe, K, Mg, Na, P, Si and Ti) based on a customized thermodynamic database. Results show that carbonation reactions between alkalis and CO/CO 2 can be occurred during gas cooling, leading to form alkali carbonates in the condensed phase. The temperature window forming melts varies with the change of the downstream pressure of syngas and the elemental composition of biomass. As the syngas pressure in the downstream process decreases, the initial temperature of forming melts during gas cooling is reduced. For biomass lower in K/Cl ratio, the condensate with the largest mass formed during gas cooling is potassium chloride. The condensation rate of Cl increases with the decrease of the K/Cl ratio in biomass. [ABSTRACT FROM AUTHOR]

In a biomass gasification process, condensation of inorganic species can cause problems such as corrosion and deposition on the downstream equipment. In this work, in order to investigate the condensation of inorganics during the gas cooling step of the biomass gasification system, both experimental and modelling studies were conducted. Experiments were performed on a pilot-scale steam/oxygen blown fluidized bed gasification facility. A CO 2 cooled probe was located at the head of a filter to condense inorganic species. Five thermocouples were used to monitor the probe temperature profile. Deposits on the probe were characterized using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) to analyze the elemental composition of deposits. A process model based on the local chemical and phase equilibriums was developed using software SimuSage to predict both release and condensation of inorganics. A customized thermodynamic database extracted from the FactSage 7.1 was used during model calculations. Two cases including with and without addition of bed material were calculated. Results show that the identified elemental compositions of deposit under different gas cooling temperatures reasonably agree with the elemental compositions predicted by model calculations. This demonstrates that the established model and the customized thermodynamic data are valid. A large amount of carbon is identified in the deposit of low temperature probe sections, which may come from the condensed tar. Additionally, a temperature window is found, where melts are formed during gas cooling. [ABSTRACT FROM AUTHOR]

The challenges of replacing fossil fuel with renewable energy in steel industry furnaces include not only reducing CO 2 emissions but also increasing the system energy efficiency. In this work, a multi-stage gasification system is chosen for the integration with a heat treatment furnace in the steel powder industry to recover different rank/temperature waste heat back to the biomass gasification system, resulting higher system energy efficiency. A system model based on Aspen Plus was developed for the proposed integrated system considering all steps, including biomass drying, pyrolysis, gasification and the combustion of syngas in the furnace. Both low temperature (up to 400 °C) and high temperature (up to 700 °C) heat recovery possibilities were analysed in terms of energy efficiency by optimizing the biomass pretreatment temperature. The required process conditions of the furnace can be achieved by using syngas. No major changes to the furnace, combustion technology or flue gas handling system are necessary for this fuel switching. Only a slight revamp of the burner system and a new waste heat recovery system from the flue gases are required. Both the furnace efficiency and gasifier system efficiency are improved by integration with the waste heat recovery. The heat recovery from the hot furnace flue gas for biomass drying and steam superheating is the most promising option from an energy efficiency point of view. This option recovers two thirds of the available waste heat, according to the pinch analysis performed. Generally, depending on the extent of flue gas heat recovery, the system can sustain up to 65% feedstock moisture content at the highest pyrolysis temperature studied. [ABSTRACT FROM AUTHOR]

Highlights: [•] We have used an advanced kinetic model for pyrolysis coupled with CFD in 3D. [•] The yields are compared to experimental results and shows a not too far-off prediction. [•] The simulations are very time consuming but makes it possible to explore secondary reactions. [•] For example, a number of thermal cracking reactions are applied to the tar components to see the effect. [Copyright &y& Elsevier]

Highlights: [•] An equation was developed for pressure drop prediction with shrinking effect. [•] Graphical representations of correlation constants were introduced. [•] This would provide a guide to select pellet size and designing a grate. [ABSTRACT FROM AUTHOR]

This study aims to improve the quality and yield of bio-oil produced from ex-situ catalytic pyrolysis of lignocellulosic biomass (sawdust) using a combination of stage catalysts with Al-MCM-41, HZSM-5, and ZrO 2. The research employed various methods, including thermogravimetric analysis (TGA), differential scanning calorimetry, bench-scale experiments, and process simulations to analyze the kinetics, thermodynamics, products, and energy flows of the catalytic upgrading process. The introduction of ZrO 2 enhances the yield of monoaromatic hydrocarbons (MAHs) in heavy organics. Compared with the dual-catalyst case, the MAHs yield escalates by approximately 344% at a catalyst ratio of 1:3:0.25. Additionally, GC-MS data indicate that the incorporation of ZrO 2 promotes the deoxygenation reaction of the guaiacol compound and the oligomerization reactions of PAHs. The integration of ZrO 2 as the third catalyst enhances the yield of heavy organics significantly, achieving 16.85% at a catalyst ratio of 1:3:1, which increases by nearly 35.6% compared to the dual-catalyst case. Also, the addition of ZrO 2 as the third catalyst enhanced the energy distribution in heavy organics. These findings suggest that the combination of these catalysts improves the fuel properties and yields of the bio-oil. [Display omitted] • The case with catalyst ratio of 1:3:0.25 has the highest yield of MAHs around 1.96%. • The case with catalyst ratio of 1:3:1 shows the highest yield of heavy organics at 16.85 %. • The implementation of ZrO 2 plays a catalytic role in deoxygenation reactions of guaiacols. • The third catalytic stage enhances the energy distribution in heavy organics. [ABSTRACT FROM AUTHOR]

Abstract: Torrefied biomass has several benefits, such as higher energy density, good grindability, higher flowability and uniformity. The process of torrefaction moves the chemical and physical properties of raw biomass close to that of bituminous coal, which allows co-utilization with high substitution ratios of biomass in the existing coal-fired boilers without major modifications. In this study, a torrefaction based co-firing system was proposed and studied. Devolatilization and char oxidize kinetics of the torrefied biomass have been investigated experimentally. CFD modeling of co-firing with varying substitutions of torrefied biomass in a pulverized coal boiler have been carried out. To figure out the boiler performance when co-firing torrefied biomass, five different cases were involved and simulated, coal only, 25% biomass, 50% biomass, 75% biomass, and 100% biomass on thermal basis, respectively. The results showed torrefaction is able to provide a technical option for high substitution ratios of biomass in the co-firing system. The case-study pulverized coal boiler could be fired 100% torrefied biomass without obvious decreasing of the boiler efficiency and fluctuation of boiler load. More positively, the net CO2 and the NO x emissions significantly reduced with increasing of biomass substitutions in the co-firing system. [Copyright &y& Elsevier]

Abstract: Steam explosion (SE) pretreatment has been implemented for the production of wood pellet. This paper investigated changes in biomass structure due to implication of steam explosion process by its pyrolysis behavior/characteristics. Salix wood chip was treated by SE at different pretreatment conditions, and then pyrolysis characteristic was examined by thermogravimetric analyzer (TGA) at heating rate of 10K/min. Both pyrolysis characteristics and structure of biomass were altered due to SE pretreatment. Hemicellulose decomposition region shifted to low temperature range due to the depolymerization caused by SE pretreatment. The peak intensities of cellulose decreased at mild pretreatment condition while they increased at severe conditions. Lignin reactivity also increased due to SE pretreatment. However, severe pretreatment condition resulted in reduction of lignin reactivity due to condensation and re-polymerization reaction. In summary, higher pretreatment temperature provided more active biomass compared with milder pretreatment conditions. [Copyright &y& Elsevier]

The use of catalytic fast pyrolysis (CFP) of biomass to produce high-quality bio-oils as potential substitutes for conventional fuels plays an essential role in the decarbonization of the world. In this study, continuous CFP tests of sawdust using three commercial-ready catalysts were performed. The overall objective is to screen appropriate catalysts and catalyst loading amounts for further commercialization and upgrading by evaluating the quality of the organic fraction bio-oils and clarifying the relationship between the hydrogen-to-carbon atomic effective (H/C eff) ratio and bio-oil yield. The results displayed that, owing to a cracking effect of the catalyst, all catalytic cases had higher H/C eff ratios and larger relative area percentages of hydrocarbons determined by NMR. Thermogravimetric analysis reveals that, compared to non-catalytic bio-oils, catalytic bio-oils showed more distillates in the diesel range. Increasing the catalyst-loading amount also showed the same effect. Overall, all bio-oil products from catalytic cases had H/C eff ratios higher than 0.6, indicating the production of promising oil for hydrodeoxygenation. By analyzing and fitting the data from this work and comparing with the literature, it could be concluded that its yield would decrease as the bio-oil product quality increases (the H/C eff ratios increase). [Display omitted] • Continuous CFP tests were conducted, providing insight for scaling up. • Three different commercial-ready catalysts with two WHSV values were studied. • All catalysts-induced oil products with H/C eff higher than 0.6. • SA catalyst induced the most attractive oil production at WHSV of 0.5. • A negative correlation between H/C eff ratio and bio-oil yield was verified. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biomass pyrolysis and in-line cascaded catalytic reforming for syngas production. • Applying Pre-reforming (biochar) + Primary reforming (Ni-based) catalysts. • 71.28 wt% syngas is obtained, with 89.47 vol% of (H 2 + CO) • Gas Energy Conversion Efficiency (GECE) of the optimal process was 75.65% • Low carbon-footprint hydrogen production: 3 kg-CO 2 /kg-H 2 produced. A novel pyrolysis followed by in-line cascaded catalytic reforming process without additional steam was developed to produce high-purity syngas from woody biomass. The key to the proposed process is the construction of a cascaded biochar + NiAl 2 O 4 catalytic reforming process in which biochar acts as a pre-reforming catalyst, and NiAl 2 O 4 acts as a primary reforming catalyst. The large oxygenates in the pyro-vapors are deeply cracked in the biochar layer due to the increased residence time in the hot-biochar bed. The remaining small molecules are then reformed with the autogenerated steam from pyrolysis catalyzed by the reduced Ni0 species in the NiAl 2 O 4 catalyst (NiAlO). The results showed that the yield of syngas for the optimized process was 71.28 wt% (including 44.44 mg-H 2 /g-biomass and 536.48 mg-CO/g-biomass), and the CO 2 yield of the process was only 3 kg-CO 2 /kg-hydrogen. High-purity syngas with 89.47 vol% of (H 2 + CO) was obtained, and the gas energy conversion efficiency (GECE) of the process reached 75.65%. The study shows that in the cascaded catalytic reforming process, cracking of the large oxygenates and reforming of the small molecules are promoted sequentially in separated biochar + NiAlO catalyst layers, which maximizes the syngas production and improves the activity and stability of the Ni-based catalyst. [ABSTRACT FROM AUTHOR]

We have investigated and modeled the injection of biomass into blast furnaces (BF), in place of pulverized coal (PC) from fossil sources. This is the easiest way to reduce CO 2 emissions, beyond efficiency-improvements. The considered biomass is either pelletized, torrefied or pyrolyzed. It gives us three cases where we have calculated the maximum replacement ratio for each. It was found that charcoal from pyrolysis can fully replace PC, while torrefied material and pelletized wood can replace 22.8% and 20.0% respectively, by weight. Our energy and mass balance model (MASMOD), with metallurgical sub-models for each zone, further indicates that (1) more Blast Furnace Gas (BFG) will be generated resulting in reduced fuel consumption in an integrated plant, (2) lower need of limestone can be expected, (3) lower amount of generated slag as well, and (4) reduced fuel consumption for heating the hot blast is anticipated. Overall, substantial energy savings are possible, which is one of the main findings in this paper. Due to the high usage of PC in Sweden, large amounts of biomass is required if full substitution by charcoal is pursued (6.19 TWh/y). But according to our study, it is likely available in the long term for the blast furnace designated M3 (located in Luleå). Finally, over a year with almost fully used production capacity (2008 used as reference), a 28.1% reduction in on-site emissions is possible by using charcoal. Torrefied material and wood pellets can reduce the emissions by 6.4% and 5.7% respectively. The complete replacement of PC in BF M3 can reduce 17.3% of the total emissions from the Swedish steel industry. [ABSTRACT FROM AUTHOR]

Highlights: [•] The performances of torrefaction based co-firing power plant are simulated by using Aspen Plus. [•] Mass loss properties and released gaseous components have been studied during biomass torrefaction processes. [•] Mole fractions of CO2 and CO account for 69–91% and 4–27% in total torrefied gases. [•] The electrical efficiency reduced when increasing either torrefaction temperature or substitution ratio of biomass. [Copyright &y& Elsevier]

Fastpyrolysis of biomass, using steam as a fluidizing agent, providesseveral benefits. In this paper, an unsteady multiphase computationalfluid dynamics (CFD) model coupled with a comprehensive kinetic schemefor primary pyrolysis is used to obtain the formation rates of primaryproducts and compare the profiles when operating with steam and nitrogen.The model only considers the physical effects of the fluidizing gasat the moment, although a literature review indicates the existenceof various chemical and surface-interacting effects. At stabilizedpyrolysis reaction rates, the product yields were compared to datafound in the literature, which indicated similar yields; this supportsthe correct implementation of the kinetic model. However, the differencein overall rate and composition is very small when steam is comparedto nitrogen. The simultaneous simulation of bed dynamics indicatea shifted formation rate of primary products toward the lower partof the fluidized bed, with an increase in solid–vapor contacttime and better temperature distribution as a result. More specifically,total heat flux to the biomass increased by 13% in the lowest partof the reactor. In addition, more heat from the sand is carried throughthe gas phase when using steam: an increase by 9% in the overall reactor(25% in the lowest part), as indicated by the results. Finally, sinceno substantial differences in overall product formation rate and compositionwere found, the considerable effect of steam found in experimentsand the literature is mainly (not exclusively) attributed to the chemicaland surface-interacting mechanisms. Because of the complex natureof secondary pyrolysis in this process, a comprehensive gas-phasekinetic model is needed to investigate the effects of steam further.Coupling of both is difficult, because of computational constraints,as the present model already is very demanding. The obtained profilesof formation rate of primary products can however be used as an inputto another model specifically made for studying homogeneous secondarypyrolysis reactions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Biomasses were devolatilized at high temperatures and high heating rates. [•] Biomass decreases its reactivity after torrefaction. [•] The kinetic parameters of torrefied biomasses were determined. [•] CO and H2 are main released volatiles during devolatilization of torrefied biomass. [ABSTRACT FROM AUTHOR]

Abstract: In this study a bimetallic dolomite based tar cracking catalyst was developed and tested. It was enriched in Ni and Fe with BET surface area of 12.31m2/g. The catalytic characterizations were tested with tar simulated by naphthalene, and with tar produced by biomass and coal co-pyrolysis. 93% naphthalene was decomposed at 950°C. A first order apparent kinetic model was developed. Activation energy of 63.96kJ/mol and pre-exponential factor of 396.2/s were calculated. Furthermore, reduction in char yield by 7%, when the catalyst was used in the biomass–coal co-pyrolysis, was observed. [Copyright &y& Elsevier]

Primary fragmentation during rapid pyrolysis is considered to be the critical size reduction mechanism as it determines the particle size distribution and char conversion rates in the fixed bed gasifier. This study aims to investigate the primary fragmentation behavior of Refuse Derived Fuel (RDF) pellets during a rapid pyrolysis process. RDF pellets consisted of different blending ratios of cardboard and polyethylene (PE) were produced by a single-pellet densification process. Pyrolysis tests at temperature ranges of 500–700 °C were performed for each pellet type, and the number and particle size of the fragmented particles were analyzed. The results demonstrate that the different composition of RDF causes different particle binding mechanisms that behave differently during pyrolysis. Densification of cardboard particles can maintain the structure of the pellet char at higher temperatures compared to PE, due to the more stable lignin binding mechanism. A modified Fragmentation Ratio (FR) is introduced to quantify the degree of fragmentation. It is shown that a raise of the concentration of PE from 25 to 75 wt% increases the FR value by up to 4.2 times, whereas an increase in pyrolysis temperature from 500 to 700 °C only slightly changes the FR values. It can be concluded that the type of materials in the RDF pellet has a more dominating effect on the fragmentation compared to the pyrolysis temperature. Further, the volatile matter content of pellets shows a linear correlation with the FR value, whereas no clear relation is found in the case of the pellet's mechanical strength. • Fragmentation RDF pellets were examined during pyrolysis tests at 500–700 °C. • Effects of pyrolysis temperature and pellet compositions were investigated. • Pellets with high cardboard and low plastic contents are less fragmented. • Volatile matter content of pellets shows a linear relation with the fragmentation degree. [ABSTRACT FROM AUTHOR]

• The acid-base properties of chemical reagents exhibited obvious influence on pyrolysis behavior and WV properties. • Chemical pretreatments promoted the pyrolysis process, and acids showed the more obvious effects than alkalis. • Chemical pretreatments increased organic content of WV. • Chemical pretreatments enhanced the relative content of phenols in WV with different levels. • The relative content of acids increased by inorganic acids pretreated, but reduced by alkalis and organic acids pretreated. Pyrolysis of biomass is an effective approach to produce high-value added solid, liquid and gaseous products. Wood vinegar (WV) is obtained as one of the main liquid products of biomass pyrolysis and has been used as the sustainable chemicals in agriculture. In this study, the effects of acid-base properties of chemical reagents on the biomass pyrolysis behavior and WV properties were investigated, and the mechanism was further discussed. The results indicated that acid-base properties of chemical reagents exhibited the significant effects on pyrolysis behavior and WV properties. Alkaline compounds showed the more obviously effects on changes in biomass chemical structure rather than acids, while acids removed the metallic species more efficiently than alkaline compounds. All chemical pretreatments increased the cellulose crystallinity, and the alkaline compounds were more favorable than the acidic compounds for increasing the crystallinity. Meanwhile, chemical pretreatments changed the chemical structure of biomass and promoted the pyrolysis process. All chemical pretreatments increased the organic content of WV. The relative content of phenols increased after all pretreatments, which increased more obviously by the acids pretreatments. Whereas, the relative content of acids decreased after pretreated by inorganic acids, and increased after pretreated by organic acids and alkaline compounds. [ABSTRACT FROM AUTHOR]

Gasification of excavated landfill waste is one of the promising options to improve the added-value chain during remediation of problematic old landfill sites. Steam gasification is considered as a favorable route to convert landfill waste into H 2 -rich syngas. Co-gasification of such a poor quality landfill waste with biochar or biomass would be beneficial to enhance the H 2 concentration in the syngas, as well as to improve the gasification performance. In this work, steam co-gasification of landfill waste with biochar or biomass was carried out in a lab-scale reactor. The effect of the fuel blending ratio was investigated by varying the auxiliary fuel content in the range of 15–35 wt%. Moreover, co-gasification tests were carried out at temperatures between 800 and 1000 °C. The results indicate that adding either biomass or biochar enhances the H 2 yield, where the latter accounts for the syngas with the highest H 2 concentration. At 800 °C, the addition of 35 wt% biochar can enhance the H 2 concentration from 38 to 54 vol%, and lowering the tar yield from 0.050 to 0.014 g/g-fuel-daf. No apparent synergetic effect was observed in the case of biomass co-gasification, which might cause by the high Si content of landfill waste. In contrast, the H 2 production increases non-linearly with the biochar share in the fuel, which indicates that a significant synergetic effect occurs during co-gasification due to the reforming of tar over biochar. Increasing the temperature of biochar co-gasification from 800 to 1000 °C elevates the H 2 concentration, but decreases the H 2 /CO ratio and increases the tar yield. Furthermore, the addition of biochar also enhances the gasification efficiency, as indicated by increased values of the energy yield ratio. • Steam co-gasification of landfill waste with biochar or biomass was carried out. • No clear synergetic effect was observed in the case of biomass co-gasification. • The addition of biochar promotes synergetic effects on the H 2 yield production. • Addition of biochar produces higher H 2 yield than that of biomass. [ABSTRACT FROM AUTHOR]

• Significant reduction of Alkali and Alkaline Earth Metal (AAEM) in the biomass with acid-leaching treatment. • The Higher Heating Value (HHV) is not significantly influenced by the acid-leaching treatment. • The removal of AAEM significantly affected the degradation of hemicellulose, cellulose, and lignin. • The second order (F2) mechanism can illustrate the catalytic pyrolysis process of lignocellulose biomass. • Acid-leaching process prior to catalytic pyrolysis promotes high devolatilization and reaction rate. Improvements on the pyrolysis process of biomass fuels are needed to obtain a high-quality of bio-oil. Pre-treatment by acid leaching prior to the pyrolysis process is considered to remove Alkali and Alkaline Earth Metal (AAEM) from the biomass, since AAEM adversely affect the catalytic pyrolysis process. Therefore, the main objective of the present work was to determine and compare the effect of mixed-catalysts consisting of H-ZSM-5 and Al-MCM-41, which are used at different ratios in lignocellulose biomass pyrolysis via Thermal Gravimetric Analysis (TGA) for both, un-leached and leached biomass. In addition, the activation energies have been determined based on the solid-state reaction mechanism. The results from the acid leaching treatment showed that the optimum leaching process was set to 30 min, 30 °C and 5 wt% acetic acid in the leaching liquid. This resulted in 59%, 95%, 99%, and 96% reduction degree of Calcium (Ca), Magnesium (Mg), Potassium or Kalium (K), and Natrium (Na), respectively. The Higher Heating Values (HHVs) for un-leached and leached biomass were 19.42 and 19.14 MJ/kg, respectively, calculated by using the Milne formula. The HHV value is not significantly influenced by the acid-leaching pre-treatment. Thermogravimetric analysis showed similar trends for the mass loss as a function of temperature and four stages could be determined from the thermal degradation of biomass. There was no significant shift in the temperature profiles between un-leached and leached biomass degradations. However, the removal of AAEM significantly affected the degradation of hemicellulose, cellulose, and lignin. A 12.4–18.2% increase of mass losses could be found in Phase 2 for leached biomass, compared to un-leached biomass. The mass losses in Phase 2 also increased with increased heating rates. From the un-leached biomass experiments using a catalyst mixture, the percentage of mass loss increased from 64.95 wt% at 10 K min−1 to 68.33 wt% at 50 K min−1. Moreover, for the leached biomass, it rose from 65.71 wt% at 10 K min−1 to 66.73 wt% at 30 K min−1, before decreasing to 62.44 wt% at 50 K min−1. A lower mass loss in Phase 4 for leached biomass compared to un-leached biomass showed the influence of an AAEM removal. The second order (F2) mechanism was able to illustrate the catalytic pyrolysis process, proven by the result that the coefficient of determination (R2) was higher than 0.99, which was high compared to other mechanisms. An acid leaching pre-treatment led to a reduction in the activation energies. The activation energies for the un-leached biomass were 26.94 and 25.56 kJ mol−1 at a heating rate of 10 K min−1 for a process without and with a catalyst mixture, respectively. The activation energies for leached biomass were 24.05 and 21.80 kJ mol−1. The results also showed that the use of the acid leaching process as a treatment prior to catalytic pyrolysis is positive, since it resulted in high devolatilization and reaction rate. [ABSTRACT FROM AUTHOR]

Until now, few studies on the valorisation of torrefaction condensable volatiles (condensates) have been performed. The composition and toxicity of torrefaction condensable volatiles determine their possible applications. Therefore, a study on the composition of wheat-barley straw torrefaction condensates, combined with toxicity tests, was performed. This analysis was mainly aimed at the utilisation of these condensates as an anaerobic digestion substrate. The torrefaction process was performed in a batch-scale reactor at temperatures from 240 °C to 320 °C. The condensates were analysed using GC/MS, and quantitative analysis was based on the calibration curves (external standard method). Toxicity tests were performed for vascular plants (Lemna sp. Growth Inhibition Test), saltwater bacteria (Microtox® bioassay) and freshwater crustaceans (Daphtoxkit F magna® survival bioassay). The condensates were classified as highly toxic for the tested organisms. Compounds that are inhibitory and/or toxic to anaerobic bacteria were detected in the samples, e.g. furfural, guaiacol, palmitic acid and oleic acid. Taking into account the condensates' high toxicity for the tested organisms and the presence of anaerobic digestion process inhibitors, there is a significant likelihood that prior detoxification of the condensates is necessary before they can be utilised as anaerobic digestion substrates. Image 1 • The higher temperature, the more diverse condensates composition. • The condensates contain phenols, furans and LCFA, considered to be toxic or/and inhibitory for anaerobic bacteria. • Regardless of the torrefaction temperature, the condensates appear to be highly toxic for the tested organisms. • The assessment of the condensate's toxicity only on the basis of the furans and phenols contents is unlikely to be accurate. [ABSTRACT FROM AUTHOR]