Numerical Investigation of the Effect of Reactor Severity on Biomass Pyrolysis Characteristics in Thermally Thick Regime (original) (raw)
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Chinese Journal of Chemical Engineering, 2012
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Advanced Powder Technology, 2007
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Chemical Engineering Research and Design, 2011
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Fuel, 2012
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Numerical and experimental modelling of biomass pyrolysis with the depollution of pyrolysis products
Fire Dynamics Simulator (FDS) and global thermochemical modelling are used to solve numerically pyrolysis, combustion and heat recuperation in a pilot plant of biomass pyrolysis using pyrolysis products as fuel. Obtained results are validated with experimental measurements. In the case of FDS modelling, three different treatments of radiation are considered: without radiation, with gray gas radiation and with non gray gas radiation. The results of numerical simulations are compared with the global model results and with the experimental results. It was shown that the FDS results are in good qualitative and quantitative agreement with the experimental results. The global model gives qualitative results in agreement with experimental results with less CPU time compared with FDS results. Whereas FDS results are more accurate than those of the global model. At the end of the process FDS results are better than global model results this is due to the fact that global model doesn't take into account the thermal inertia of the pilot plant. The global model is used to study the racing reaction in the pilot plant and to study the case with and without catalyser. FDS is used to predict CO and CO2 emissions. The effect of the non gray gas behaviour is emphasised and demonstrated to affect pollutant emissions.
Modelling and Experimental Results of a Biomass Pyrolysis Pilot Plant
Fire Dynamics Simulator (FDS) and global thermochemical modelling are used to solve numerically pyrolysis, combustion and heat recuperation in a pilot plant of biomass pyrolysis using pyrolysis products as fuel. Obtained results are validated with experimental measurements. In the case of FDS modelling, three different treatments of radiation are considered: without radiation, with gray gas radiation and with non gray gas radiation. The results of numerical simulations are compared with the global model results and with the experimental results. It was shown that the FDS results are in good qualitative and quantitative agreement with the experimental results. The global model gives qualitative results in agreement with experimental results with less CPU time compared with FDS results. Whereas FDS results are more accurate than those of the global model. At the end of the process FDS results are better than global model results this is due to the fact that global model doesn’t take i...
Biomass Pyrolysis in a Fluidized Bed Reactor. Part 1: Literature Review and Model Simulations
Industrial & Engineering Chemistry Research, 2005
Various types of cylindrical biomass particles (pine, beech, bamboo, demolition wood) have been pyrolyzed in a batch-wise operated fluid bed laboratory setup. Conversion times, product yields, and product compositions were measured as a function of the particle size (0.7-17 mm), the vapor's residence time (0.25-6 s), the position of the biomass particles in the bed (dense bed or splash zone), and the fluid bed temperature (250-800°C). For pyrolysis temperatures between 450 and 550°C, the bio-oil yield appeared to be maximal (in this work: about 65 wt %), while the water content of the bio-oil is minimal. The position of the biomass particles in the fluid bed, either in the dense bed or in the splash zone, does not affect the conversion time and product yields to a large extent during pyrolysis at 500°C. In the small fluid bed used for this work, with a char holdup of up to 5 vol % (or 0.7 wt %), the residence time of the pyrolysis vapors is not that critical. At typical fast pyrolysis temperatures of around 500°C, it appeared sufficient to keep this residence time below 5 s to prevent significant secondary cracking of the produced vapors to noncondensable gas. Up to a diameter of 17 mm, the particle size has only a minor effect on the total liquid yield. However, for particles larger than 3 mm, the water content of the produced bio-oil increases significantly. The experimental results are further compared with predictions from a one-dimensional (1D) and a two-dimensional (2D) single-particle pyrolysis model. Such models appeared to have a limited predictive power due to large uncertainties in the kinetics and selectivity of the biomass decomposition. Moreover, the product quality cannot be predicted at all.