Formation of fine particles in co-combustion of coal and solid recovered fuel in a pulverized coal-fired power station H. Wu a,⇑ , A.J. Pedersen a , P. Glarborg a , F.J. Frandsen a , K. Dam-Johansen a , B. Sander b a Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark b DONG Energy A/S, Kraftvksvej 53, 7000 Fredericia, Denmark Abstract Fine particles formed from combustion of a bituminous coal and co-combustion of coal with 7 th% (thermal percentage) solid recovered fuel (SRF) in a pulverized coal-fired power plant were sampled and characterized in this study. The particles from dedicated coal combustion and co-combustion both showed an ultrafine mode centered at approximately 0.1 lm. Compared with coal combustion, co-combustion of coal and SRF increased the formation of submicron particles, especially ultrafine particles below 0.2 lm. The morphology of the particles indicated that supermicron particles were primarily formed by the melting of minerals. The ultrafine particles were generated through nucleation and coagulation of vaporized inor- ganic species, while for the particles in between supermicron and ultrafine particles, condensation of vapor- ized species or aggregation of nucleates on the existing spherical submicron particles appear to be an important formation mechanism. The elemental composition of the particles from coal combustion showed that S and Ca were significantly enriched in ultrafine particles and P was also enriched considerably. How- ever, compared with supermicron particles, the contents of Al, Si and K were depleted in ultrafine particles. The observed high volatility of Ca was likely related with the high combustion temperature and relative low oxygen condition in the boiler which may promote vaporization of Ca during char oxidation. The discrep- ancies on the observed volatilities of Ca and alkalis between some laboratory experiments and full-scale measurements were discussed. The composition of the fine particles from co-combustion was generally sim- ilar to those from coal combustion. The ultrafine particles from co-combustion were of slightly higher Ca, P, and K contents, and lower S content. Ó 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved. Keywords: Fine particles; Pulverized coal combustion; Co-combustion; SRF; Full-scale 1. Introduction Co-combustion of coal and solid recovered fuel (SRF) derived from nonhazardous waste streams is recognized as a promising method to both reduce the CO 2 emission from pulverized coal-fired power stations and increase the efficiency of utilizing waste fuels [1]. One of the major technical concerns for applying such a technology is the influences of coal and SRF co-combustion on the emission of fine particles from the power plant, since coal-fired 1540-7489/$ - see front matter Ó 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.proci.2010.06.125 ⇑ Corresponding author. Fax: +45 45 88 22 58. E-mail address: haw@kt.dtu.dk (H. Wu). Available online at www.sciencedirect.com Proceedings of the Combustion Institute 33 (2011) 2845–2852 www.elsevier.com/locate/proci Proceedings of the Combustion Institute