<p>High-temperature falling particle receivers are being investigated for next-generation concentrating solar power applications.&nbsp; Small sand-like particles are released into an open-cavity receiver and are irradiated by concentrated sunlight from a field of heliostats.&nbsp; The particles are heated to temperatures over 700 °C and can be stored to produce heat for electricity generation or industrial applications when needed.&nbsp; As the particles fall through the receiver, particles and particulate fragments in the form of aerosolized dust can be emitted from the aperture, which can lower thermal efficiency, increase costs of particle replacement, and pose a particulate matter (PM) inhalation risk. This paper describes sampling methods that were deployed during on-sun tests to record near-field (several meters) and far-field (tens to hundreds of meters) concentrations of aerosol particles within emitted plumes. The objective was to quantify the particulate emission rates and loss from the falling particle receiver in relation to OSHA and EPA National Ambient Air Quality Standards (NAAQS).&nbsp; Near-field instrumentation placed on the platform in proximity to the receiver aperture included several real-time aerosol size distribution and concentration measurement techniques, including a Malvern SprayTec, TSI Aerodynamic Particle Sizers (APS), TSI DustTraks, Portable Optical Particle Spectrometer (POPS), Alphasense Optical Particle Counters (OPC), a Condensation Particle Counter (CPC), Cascade Particle Impactor, 3D-printed prototype tipping buckets, and meteorological instrumentation. Far-field particle sampling techniques utilized multiple tethered balloons located upwind and downwind of the particle receiver to measure the plume concentrations using a suite of airborne aerosol and meteorological instruments including POPS, CPCs, OPCs and impactors. The combined aerosol size distribution for all these instruments spanned particle sizes from 0.02 μm – 1000 μm.&nbsp; Results showed a strong influence of wind direction on particle emissions and concentration. Resulting particle concentrations are being compared to OSHA and EPA standards, as well as computational modeling.&nbsp; Results will be reported in the full paper and presentation.</p><p>Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.</p>

Near-Field and Far-Field Sampling of Aerosol Plumes to Evaluate Particulate Emission Rates From a Falling Particle Receiver During On-Sun Testing

Paper Proceedings: https://asmedigitalcollection.asme.org/ES/ES2021/volume/84881

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