Formation and Emission of Submicron Particles in Pulverized Olive Residue (Orujillo) Combustion

Abstract

The particle formation and emission in the combustion of pulverized olive residue (orujillo) is studied in this work. The fuel has been burned in controlled combustion conditions in an entrained flow reactor. A bimodal distribution with mode peaks at 155 nm and 110 µm is found for fly ashes. Coarse particles have been characterized by laser diffractometry and SEM, while fines have been analyzed by low-pressure impaction, DMA, SEM, and X-ray diffraction. Particles with Dp < 1 µm are composed of only K 2 SO 4 and KCl in the same mass proportion, and possibly K 3 PO 4 (less than 7% in mass). The use of a new particle sampling probe and a TEM allowed a detailed study of the formation of these particles when flue gases cool down. K 2 SO 4 is experimentally found to start nucleation over 900• C, while KCl is not observed at this temperature. Condensation of KCl on these nuclei is observed in a sample taken at 560• C. These "formation steps" are in good agreement with both theoretical calculations by other authors and a simple equilibrium schema shown here.

Transmission of Alkali Aerosols through Sampling Systems

“…There, it was cooled by cold-gas quenching with argon (500 mL min -1 ). While at elevated temperatures of 700°C particles nucleate and grow [26], the particle growth stops after quenching [3]. In Fig.…”

“…However, many feedstocks have high contents in alkalis, which are released during gasification and condense as particulates [2]. In the case of biomass combustion, it was shown that these particles consist to a large degree of alkali salts, namely potassium chloride and potassium sulfate [3]. Alkalis are detrimental to catalysts [4].…”

Indoor air pollution from particulate matter emissions in different households in rural areas of Bangladesh

“…Most biomass fuels are characterized by high-alkali contents [30] leading to high concentrations of fine aerosols in the flue gases [31]. In order to obtain a reliable smoke value from the fine potassium, it is necessary to subtract the fine potassium associated with the soil and sea salt components from total K [32].…”

Hygroscopic Behavior of Aerosol Particles Emitted from Biomass Fired Grate Boilers

“…These range from large-scale (25-100 MW) CFB (Circulating Fluidized Bed) boilers (e.g., Valmari et al 1999), to grate combustion in 0.5-12 MW boilers (Pagels et al 2003;Lillieblad et al 2004) to small (10-20 kW) residential wood stoves and boilers (Hedberg et al 2002;Johansson et al 2004). Emissions from other biomass fuels have also been studied, such as straw (Christensen et al 1998) and olive residues (Jimenez and Ballester 2004), as well as co-firing of biomass and fossil fuels. Biomass burning in the open resulting from wildfires and deforestation has also attracted attention (Reid et al 2004;Andreae and Merlet 2001).…”