Simultaneous sampling of PCDD/PCDF inside the combustion chamber and on four boiler levels of a waste incineration plant

The formation of dioxins in combustion systems

“…The values reported at the furnace outlet by Sakai et al [7] were 80 ng PCDD/F N m −3 , i.e., in the same range. Düwel et al [13] found ∼400 µg of PCDD and 1000 µg PCDF per ton of C as CO 2 while incinerating MSW. For a typical incinerator flue gas of 10 mol% CO 2 , these values are equivalent to 20 and 50 ng PCDD/F N m −3 of flue gas, respectively.…”

“…The OH radical is taken to be the most active oxidising species under combustion conditions. All the species may pyrolyse or oxidise to waste products in reactions (3), (13) and (8)- (11). The rate constants for reactions (1) to (13) were estimated from the literature for similar reactions.…”

“…PCDD/Fs are formed during pulp paper manufacture when bleaching is carried out with chlorine, and are by-products in the manufacture of some pesticides. The other principal source is combustion, such as waste incineration, including medical waste [13], iron ore sinter strands [14], electric arc furnaces using recycled steel [15], metal industries [16], landfill fires [17], and auto exhausts [18][19][20]. PCDD/Fs are not produced in detectable levels in cement kilns, even when firing chlorinated wastes.…”

Formation of Dioxins and Furans During Municipal Solid Waste Gasification

“…Even though it is known that dioxins and furans emerge during combustion, researchers used to believe that the high temperatures of the incineration oven destroyed them. However, PCDDs and PCDFs might arise after the gas flow leaves the combustion chamber; that is, when the gas goes through an air pollution control device that operates at lower temperatures (between 473 and 763 K) (Düwel et al, 1990;Reis, 2009). …”

Quality and generation rate of solid residues in the boiler of a waste-to-energy plant

“…BA has mainly been studied in relation to fouling and corrosion processes, and the formation of persistent organic pollutants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD and PCDF). Some studies investigated the evolution of PCDD/F levels within the boiler, analysing PCDD/F in samples collected from up to 6 different points along the boiler [8][9][10], thereby providing evidences of PCDD/F formation in the temperature range of 370-490°C. Yang et al [11] provided a more detailed characterization of BA sampled at the first superheater (flue gas temperature from 600-700°C), at the second superheater (500-600°C) and at the end of the economizer, where all BA was mixed together into one flow.…”