Sampling and Characterization of Sub-Micrometer High Temperature Particles Present in the Product Gas from a Circulating Fluidized-Bed Biomass Gasifier

摘要

The removal of particulate fine fractions by a proper high-temperature cleaning device is a very important issue in the development of the biorefinery concept Therefore, in this investigation, particles from a 100 kW_th steam-O_2 blown circulating fluidized-bed (CFB) gasifier were sampled and characterized. The sampling was performed with a specially designed heated dilution probe downstream of a high-temperature candle filter element The dilution probe was followed by a bed of activated carbon to separate the condensed phase from the particle phase by reducing the supersaturation of the volatile material. Parallel measurements were performed by a scanning mobility particle sizer (SMPS) and sample collection by a cascade impactor assembly to obtain information about the particle size distribution and elemental analysis, respectively. The measured particle mass was found to be dominated by coarse particles from bed material together with high amounts of potassium, which is thought to have penetrated through the filter. The aim of this work is to validate the developed particle measuring setup by performing physical and chemical characterization of the fine-particle fraction that is not captured by the filtering system to avoid the catalytic deactivation of the downstream upgrading processing.