The pyrolysis of wood was carried out in an Entrained Flow Reactor at high temperature (650 to 950 °C) and under rapid heating conditions (N103 Ks?1). The influence of the diameter and initial moisture of the particle, reactor temperature, residence time and the nature of the gaseous atmosphere on the composition of the gaseous products has been characterised. Particle size, between 80-125 and 160-200 ?m, did not show any impact. Pyrolysis and tar cracking essentially happen in very short time period: less than 0.6 s; the products yields are only slightly modified after 0.6 s in the short residence times (several seconds) of our experiments. Higher temperatures improve hydrogen yield in the gaseous product while CO yield decreases. Under nitrogen atmosphere, after 2 s at 950 °C, 76% (daf) of the mass of wood is recovered as gases: CO, CO2, H2, CH4, C2H2, C2H4 and H2O. Tests performed under steam partial pressure showed that hydrogen production is slightly enhanced. (Résumé d'auteur)

The pyrolysis of wood was carried out in an Entrained Flow Reactor at high temperature (650 to 950°C) and under rapid heating conditions (>10³Ks⁻¹). The influence of the diameter and initial moisture of the particle, reactor temperature, residence time and the nature of the gaseous atmosphere on the composition of the gaseous products has been characterised. Particle size, between 80–125 and 160–200μm, did not show any impact. Pyrolysis and tar cracking essentially happen in very short time period: less than 0.6s; the products yields are only slightly modified after 0.6s in the short residence times (several seconds) of our experiments. Higher temperatures improve hydrogen yield in the gaseous product while CO yield decreases. Under nitrogen atmosphere, after 2s at 950°C, 76% (daf) of the mass of wood is recovered as gases: CO, CO₂, H₂, CH₄, C₂H₂, C₂H₄ and H₂O. Tests performed under steam partial pressure showed that hydrogen production is slightly enhanced.

Torrefaction is a mild thermal pretreatment which improves biomass properties and releases condensable species. Condensable species released during torrefaction of pine, ash wood, miscanthus and wheat straw at 250, 280 and 300 °C were investigated. A fixed-bed reactor was used for the laboratory scale experiments. A micro-GC, Karl Fischer titrator and GC-MS were used to analyse incondensable gases, water and other condensable species, respectively. The overall mass balance ranged from 96 to 103 wt.%. The quantification rate of condensable species was on average 77 wt.%. In addition to the major species usually reported in the literature – water, acetic acid, 2-propanone,1-hydroxy- – we show that large amounts of some anhydrosugars were produced. Additionally, 85 condensable species were identified. Among these species, many terpenes and terpenoids in pine were identified by adsorption on SPME fibre. Finally, the influence of temperature and of the nature of biomass on the yields of condensable species was highlighted. (Résumé d'auteur)

Torrefaction is a mild thermal pretreatment which improves biomass properties and releases condensable species. Condensable species released during torrefaction of pine, ash wood, miscanthus and wheat straw at 250, 280 and 300°C were investigated. A fixed-bed reactor was used for the laboratory scale experiments. A micro-GC, Karl Fischer titrator and GC-MS were used to analyse incondensable gases, water and other condensable species, respectively. The overall mass balance ranged from 96 to 103wt.%. The quantification rate of condensable species was on average 77wt.%. In addition to the major species usually reported in the literature – water, acetic acid, 2-propanone,1-hydroxy- – we show that large amounts of some anhydrosugars were produced. Additionally, 85 condensable species were identified. Among these species, many terpenes and terpenoids in pine were identified by adsorption on SPME fibre. Finally, the influence of temperature and of the nature of biomass on the yields of condensable species was highlighted.

Brazil is the leading producer and consumer of charcoal, 75% of which goes to the steel industry alone. The carbonization processes are generally small-scale technologies that are difficult to control, with relatively low gravimetric yields. New technologies are currently being developed to improve those figures. One such technique is pressurized pyrolysis. Recent studies have shown that using pressure can increase gravimetric yields by 50% and considerably reduce carbonization time. The purpose of this paper was to study statistically how pressure impacts on the quality of the resulting charcoal. We applied a random factorial design and used the General Linear System procedure to perform the statistical analysis. The experimental study was carried out on the wood of Eucalyptus grandis and involved three relative working pressures (0, 5 and 10 bars), two carbonization temperatures (450 and 600 °C) and three wood moisture contents (0, 15 and 110%). Five response variables were analyzed and discussed following a random factorial design: charcoal yield (ychar), fixed carbon yield (yfC), bulk density (D), fixed carbon content (fC) and gross calorific value (GCV). The best "steel" quality charcoal seemed to be obtained with an anhydrous wood, a pressure of 10 bars and a temperature of 600 °C. (Résumé d'auteur)

Brazil is the leading producer and consumer of charcoal, 75% of which goes to the steel industry alone. The carbonization processes are generally small-scale technologies that are difficult to control, with relatively low gravimetric yields. New technologies are currently being developed to improve those figures. One such technique is pressurized pyrolysis. Recent studies have shown that using pressure can increase gravimetric yields by 50% and considerably reduce carbonization time. The purpose of this paper was to study statistically how pressure impacts on the quality of the resulting charcoal. We applied a random factorial design and used the General Linear System procedure to perform the statistical analysis. The experimental study was carried out on the wood of Eucalyptus grandis and involved three relative working pressures (0, 5 and 10bars), two carbonization temperatures (450 and 600°C) and three wood moisture contents (0, 15 and 110%). Five response variables were analyzed and discussed following a random factorial design: charcoal yield (ycₕₐᵣ), fixed carbon yield (yfC), bulk density (D), fixed carbon content (fC) and gross calorific value (GCV). The best “steel” quality charcoal seemed to be obtained with an anhydrous wood, a pressure of 10bars and a temperature of 600°C.

https://www.scopus.com/inward/record.url?eid=2-s2.0-84922232547&partnerID=40&md5=5d8df1d4b8ac23dc641702d585cfb57d | The use of the X-ray technique and the X-ray densitometry to determine pellet particle distribution and to understand the biomass compaction and its effects in pellet properties has been limited. The present work evaluates the quality of pellets manufactured with several lignocellulosic materials by using X-ray photography for studying surface cracks and irregularities, and by using X-ray densitometry to evaluate density and its variation in longitudinal and transversal directions. Density values and their variation were correlated to the pellets' mechanical properties (mechanical durability and compression resistance). It was found that X-ray photography may be applied to evaluate the presence of cracks and irregularities in the pellets' surface; however, these are not indicators of pellet durability or compression resistance. Moreover, density evaluation by the X-ray densitometry technique allowed the determination of the pellets' mechanical resistance and durability. A negative correlation was observed between the force at break and the coefficient of variation of density. No correlation was found between the mechanical durability and the average density or its variation. According to the above results, X-ray technique can be utilized to study the pellet quality.

The use of the X-ray technique and the X-ray densitometry to determine pellet particle distribution and to understand the biomass compaction and its effects in pellet properties has been limited. The present work evaluates the quality of pellets manufactured with several lignocellulosic materials by using X-ray photography for studying surface cracks and irregularities, and by using X-ray densitometry to evaluate density and its variation in longitudinal and transversal directions. Density values and their variation were correlated to the pellets' mechanical properties (mechanical durability and compression resistance). It was found that X-ray photography may be applied to evaluate the presence of cracks and irregularities in the pellets' surface; however, these are not indicators of pellet durability or compression resistance. Moreover, density evaluation by the X-ray densitometry technique allowed the determination of the pellets' mechanical resistance and durability. A negative correlation was observed between the force at break and the coefficient of variation of density. No correlation was found between the mechanical durability and the average density or its variation. According to the above results, X-ray technique can be utilized to study the pellet quality.