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[EN] The performance of olivine, dolomite and gamma-alumina primary catalysts was evaluated in the continuous tar elimination process in which toluene was selected as the biomass gasification tar model compound. Iron was incorporated into these catalysts in order to improve their catalytic activity. All the experiments were performed in a continuous flow fluidized bed micro-reactor, with a steam/toluene ratio of 4 and a space velocity (GHSV) of 820 h(-1), which corresponds to a catalyst amount of 3.8 cm(3). The effect of temperature was studied using olivine in the 800-900 degrees C range, which allowed concluding that 850 degrees C was the best temperature for tar removal. The fresh and deactivated catalysts were characterized by N-2 adsorption-desorption, X-ray fluorescence (XRF), X-ray diffraction (XRD) and temperature-programmed oxidation (TPO). Tar conversion efficiency was assessed by means of carbon conversion, H-2 yield (based on the maximum allowed by stoichiometry), gas composition and product yields, with Fe/Al2O3 leading to the highest conversion (87.6 %) and H-2 yield (38 %). Likewise, Fe/Al2O3 also provided the highest stability, as it allowed operating for long periods with high conversion values (85.9 % after 35 min on stream), although it underwent severe deactivation. The analysis of the spent catalysts revealed that deactivation occurred mainly by coke deposition on the catalyst surface and iron phase oxidation, with Fe/olivine and Fe/dolomite leading to the faster deactivation due to their poorer metal dispersion related to their reduced surface area. The TPO profiles showed that the coke deposited on the three catalysts was amorphous with a very small contribution of highly structured carbon.

[EN] The performance of olivine, dolomite and gamma-alumina primary catalysts was evaluated in the continuous tar elimination process in which toluene was selected as the biomass gasification tar model compound. Iron was incorporated into these catalysts in order to improve their catalytic activity. All the experiments were performed in a continuous flow fluidized bed micro-reactor, with a steam/toluene ratio of 4 and a space velocity (GHSV) of 820 h(-1), which corresponds to a catalyst amount of 3.8 cm(3). The effect of temperature was studied using olivine in the 800-900 degrees C range, which allowed concluding that 850 degrees C was the best temperature for tar removal. The fresh and deactivated catalysts were characterized by N-2 adsorption-desorption, X-ray fluorescence (XRF), X-ray diffraction (XRD) and temperature-programmed oxidation (TPO). Tar conversion efficiency was assessed by means of carbon conversion, H-2 yield (based on the maximum allowed by stoichiometry), gas composition and product yields, with Fe/Al2O3 leading to the highest conversion (87.6 %) and H-2 yield (38 %). Likewise, Fe/Al2O3 also provided the highest stability, as it allowed operating for long periods with high conversion values (85.9 % after 35 min on stream), although it underwent severe deactivation. The analysis of the spent catalysts revealed that deactivation occurred mainly by coke deposition on the catalyst surface and iron phase oxidation, with Fe/olivine and Fe/dolomite leading to the faster deactivation due to their poorer metal dispersion related to their reduced surface area. The TPO profiles showed that the coke deposited on the three catalysts was amorphous with a very small contribution of highly structured carbon.

[EN] The performance of olivine, dolomite and gamma-alumina primary catalysts was evaluated in the continuous tar elimination process in which toluene was selected as the biomass gasification tar model compound. Iron was incorporated into these catalysts in order to improve their catalytic activity. All the experiments were performed in a continuous flow fluidized bed micro-reactor, with a steam/toluene ratio of 4 and a space velocity (GHSV) of 820 h(-1), which corresponds to a catalyst amount of 3.8 cm(3). The effect of temperature was studied using olivine in the 800-900 degrees C range, which allowed concluding that 850 degrees C was the best temperature for tar removal. The fresh and deactivated catalysts were characterized by N-2 adsorption-desorption, X-ray fluorescence (XRF), X-ray diffraction (XRD) and temperature-programmed oxidation (TPO). Tar conversion efficiency was assessed by means of carbon conversion, H-2 yield (based on the maximum allowed by stoichiometry), gas composition and product yields, with Fe/Al2O3 leading to the highest conversion (87.6 %) and H-2 yield (38 %). Likewise, Fe/Al2O3 also provided the highest stability, as it allowed operating for long periods with high conversion values (85.9 % after 35 min on stream), although it underwent severe deactivation. The analysis of the spent catalysts revealed that deactivation occurred mainly by coke deposition on the catalyst surface and iron phase oxidation, with Fe/olivine and Fe/dolomite leading to the faster deactivation due to their poorer metal dispersion related to their reduced surface area. The TPO profiles showed that the coke deposited on the three catalysts was amorphous with a very small contribution of highly structured carbon.

The slow pyrolysis of recycled high-density polyethylene (HDPE) has been investigated in a batch autoclave reactor at 430–490 °C and reaction times of 15–60 min, with the aim of obtaining the maximum yield of plastic oil (PO) with an adequate composition for its subsequent valorization in refinery. Specifically, PO yields up to 85–90 wt% have been achieved operating at 430 °C and 15–37.5 min, noting that the obtained yields strongly depend on temperature and, to a lesser extent, on reaction time. Simulated distillation and gas chromatography analyses of PO have shown its potential for its valorization in a waste refinery scheme targeting the production of alternative fuels. Thus, the PO obtained at 430 °C and 15 min is suitable to be cofed to the fluidized catalytic cracking (FCC) unit since it has a simulated distillation curve similar to that of vacuum gasoil (VGO). On the other hand, the PO obtained at 430 °C at the longest reaction time and those obtained at 460 °C are suitable to be fed together with light cycle oil (LCO) into a hydroprocessing unit. The composition of naphtha and middle distillates of PO reveals that these fractions are appropriate for their blending with commercial diesel and gasoline pools after a mild hydrotreating to reduce their olefin content.