The present work focuses on the sampling procedure and quantification of the PAH yield from the fast pyrolysis of waste softwood. In particular, fast pyrolysis experiments were conducted using a CDS Pyroprobe 5200 at temperatures between 500 °C and 1000 °C, at a heating rate of 600 °C/s for a sample size of 30 mg. High performance liquid chromatography (HPLC) was used for the determination of the PAH compounds present in the liquid sample fraction, while a micro – GC was employed for the analysis of the main gaseous products (CO, CO₂, CH₄ and H₂). An alternative tar sampling protocol was proposed, which employed the use of a cold trap (50 °C) and an isopropanol filled impinger bottle for the collection of the condensable products. The experiments were compared to heated foil reactor based pyrolysis tests within the same temperature range and heating rate, except for a slightly lower sample size (10 mg). The Pyroprobe and adapted sampling system proved to be more efficient regarding PAH capture and quantification compared to the heated foil reactor. Naphthalene, acenaphthylene and phenanthrene were the main PAH compounds detected. The PAH yields increased with pyrolysis temperature, up to values corresponding to roughly 0.2 wt% of the overall yield at 1000 °C. From the results it was derived that PAH evolution is mainly a product of secondary decomposition of primary tar, since the char yield stabilized for higher temperatures and the yields of CO, H₂ and CH₄ increased. Overall mass balance closure values were around 80 wt% on average. Char and gas yields were determined with high reproducibility, however gravimetric liquid analysis lacked due to the inability to gravimetrically measure the yield condensing in the impinger bottle. Future work is aimed on improving on this particular aspect. Overall, the alternative tar sampling system proposed was successful in the quantification of PAH from biomass fast pyrolysis experiments offering increased flexibility, accuracy and practicality of use.

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In this study torrefied feedstocks, consisting of mixed wood and wood residues torrefied at 300 °C and ash wood torrefied at 250 and 265 °C, were pyrolyzed in a pyroprobe at five pyrolysis temperatures (600–1000 °C) and a fast heating rate (600 °C·s−1) to investigate the effect of torrefaction on the formation of volatiles and their evolution in a 100 kW circulating fluidized bed gasifier. Results showed that torrefaction converted mostly the hemicellulose content of feedstocks. Furthermore, torrefaction resulted in decreasing the bio-oil and gas yields, increasing the char and phenol yields and not affecting the polyaromatic hydrocarbons yield. Phenol and naphthalene showed the largest yield at 600–700 °C and 800–1000 °C, respectively. At such high temperatures, the rest polyaromatic hydrocarbons showed yields similar to phenol's. At 900 °C torrefaction affected mainly the phenolic species, with 4-propyl-phenol being the dominant species of its group for mixed wood and wood residues feedstock. In the gasifier, H2 and CO2 yields increased, CH4 yield remained constant, and CO yield depended on tar conversion and oxidation and steam reactions. The phenol and naphthalene yields further decreased and increased, respectively, whereas, polyaromatic hydrocarbons did not change in the gasifier.@en

Fast pyrolysis characterization of three dry manure samples was studied using a pyrolyzer. A heating rate of 600°C/s and a holding time of 10 s were selected to reproduce industrial conditions. The effect of the peak pyrolysis temperature (600, 800 and 1000°C) on the pyrolysis product yield and composition was evaluated. Char and bio-oil were gravimetrically quantified. Scanning electron microscopy (SEM) was used to analyse the char structure. H2, CH4, CO and CO2 were measured by means of gas chromatography (GC). A decrease in the char yield and an increase of the gas yield were observed when temperature increased. From 800°C on, it was observed that the char yield of samples Dig R and SW were constant, which indicated that the primary devolatilization reactions stopped. This fact was also corroborated by GC analysis. The bio-oil yield slightly increased with temperature, showing a maximum of 20.7 and 27.8 wt.% for samples Pre and SW, respectively, whereas sample Dig R showed a maximum yield of 16.5 wt.% at 800°C. CO2 and CO were the main released gases whereas H2 and CH4 production increased with temperature. Finally, an increase of char porosity was observed with temperature.@en

There are various attempts to industrialize the supercritical water gasification (SCWG) of wet biomass process, however, there are still process challenges to overcome. Such challenges include slurry pumpability, energy efficiency, low conversion, char and tar formation, and clogging problems due to salt precipitation. Fortunately, some of the aforementioned challenges can be eliminated by having long residence times, high heating rates and utilization of fluidized bed reactors. This study presents the first results and experiences obtained from the TU Delft/Gensos semi-pilot scale setup which has a capacity of 50 kg/h and incorporates a fluidized bed reactor. A dry starch concentration of 4.4 wt % was used as feedstock. Reactor temperatures of 500 °C, 550 °C and 600 °C, and the mass flow rates of 24.5 kg/h and 35 kg/h were tested. The results indicate that the heating profile in the heat exchanger and the residence time at higher temperatures (>500 °C) play a significant role in the conversion efficiencies. No clogging problem was observed, however small quantities of char (2.3 wt % at highest) and oil production (10.4 wt % at highest) were observed. The highest carbon gasification efficiency was 73.9% and this was obtained at a reactor temperature of 600 °C and at a feed flow rate of 24.5 kg/h.

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Several Mousterian sites in France have yielded large numbers of small black blocs. The usual interpretation is that these ‘manganese oxides’ were collected for their colouring properties and used in body decoration, potentially for symbolic expression. Neanderthals habitually used fire and if they needed black material for decoration, soot and charcoal were readily available, whereas obtaining manganese oxides would have incurred considerably higher costs. Compositional analyses lead us to infer that late Neanderthals at Pech-de-l’Azé I were deliberately selecting manganese dioxide. Combustion experiments and thermo-gravimetric measurements demonstrate that manganese dioxide reduces wood’s auto-ignition temperature and substantially increases the rate of char combustion, leading us to conclude that the most beneficial use for manganese dioxide was in fire-making. With archaeological evidence for fire places and the conversion of the manganese dioxide to powder, we argue that Neanderthals at Pech-de-l’Azé I used manganese dioxide in fire-making and produced fire on demand.@en

Fast devolatilization of woody (mixture of softwoods) and herbaceous (reed) biomasses has been studied in a heated foil reactor coupled to an FTIR spectrophotometer. Biomass fuels were chosen based on their potential for contributing to power generation on an industrial scale through gasification in The Netherlands. Heating rate (600 °C/s) and holding time (10 s) at peak pyrolysis temperature were chosen to correspond to conditions encountered in industrial processes. The effect of peak pyrolysis temperature on pyrolysis products was investigated. Particular emphasis was given to tar collection, and subsequent gravimetric quantification. The results indicated a strong total weight loss increase with temperature, to reach an asymptote char yield of 16.7 wt.% at 800 °C and of 32.4 wt.% at 700 °C for wood and reed, respectively. Reed primary devolatilization reactions ceased at lower temperatures compared to wood. The latter was confirmed by the lower activation energy of reed (32.1 kJ/mol) compared with that of wood (38.4 kJ/mol) during extrapolation of kinetic data from the fast devolatilization experiments. CO2 dominated the gaseous products released at lower temperatures (< 700 °C) while CO became predominant at higher pyrolysis temperatures (> 700 °C) reaching a maximum of 19.1 wt.% and 18 wt.% for wood and reed, respectively, at 1000 °C. Maximum tar yields of 38.8 wt.% (d.b.) of dry wood and 23.3 wt.% (d.b.)of dry reed were able to be recovered at 600 °C. An overall mass balance of approximately 90 wt.% (d.b.) for both biomass fuels was obtained at high (900–1000 °C) pyrolysis peak temperatures.@en