Fly-ash emissions control efficiency and heavy metals particle size distribution in an application of a hybrid filter to biomasswaste co-firing flue gas
- Gaizka Aragón
- David Sanz
- Enrique Rojas
- Jesús Rodríguez-Maroto
- Raquel Ramos
- Ricardo Escalada
- Elena Borjabad
- Miren Larrión
- Iñaki Mujica
- Cristina Gutiérrez-Cañas
- Jordi Grifoll (coord.)
- Joan Rosell-Llompart (coord.)
Editorial: Publicacions URV ; Universitat Rovira i Virgili
ISBN: 978-84-695-9978-5
Año de publicación: 2014
Páginas: 9-13
Congreso: Iberian Meeting on Aerosol Science and Technology (2. 2014. Tarragona)
Tipo: Aportación congreso
Resumen
Control of emissions of heavy metals is a necessary requirement for waste-to-energy combustion applications. Even in biomass combustion, emissions of certain heavy metals may pose a so far unnoticed or underestimated risk. Hybrid filters (HF) (combination of electrostatic precipitator and fabric filter) applied to the control of emissions of particulate matter (PM) present more robust performance under varying operating conditions, and increased efficiency in the control of PM emissions in the particle size range where a greater enrichment in heavy metals is expected. This paper investigates the fractional penetration and enrichment in fly-ash of different metals of interest, under different operating conditions, through a semi-industrial scale HF applied to the control of emissions from cocombustion of biomass and wastes. Heavy metals size distribution in fly-ash was determined. Depending on operating conditions, an average efficiency of 96.85 to 99.41% in terms of total mass concentration of PM was found. Some of the corresponding values for heavy metals were 79.17-98.57%, in the case of Pb, and 93.63-99.27% , in the case of Cu, in the solid phase; note that some elements may be also present in vapor phase depending on volatility. A preferential enrichment in Cl, Na, K, Cd, and Pb was found in the fly-ash collected in the fabric filter module. Copper was found preferably in the submicron fraction of the raw fly-ash, being able the HF to produce a depurated emission without preferential size enrichment in Cu. The HF ability to efficiently control emissions of both overall PM, and heavy metals fraction in particular was demonstrated within a wide range of load and different fuels. The preferential occurrence of some heavy metals in the ultrafine fraction of fly-ash has been detected, which makes clear the need of effective control systems for PM in that size range.