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.

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.

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.