Effect of Gaseous Inhibitors on PCDD/F Formation

• Published in: Environmental science & technology Vol. 32; no. 20; pp. 3099 - 3103
• Main Authors: Ruokojärvi, Päivi H, Halonen, Ismo A, Tuppurainen, Kari A, Tarhanen, Juhani, Ruuskanen, Juhani
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.10.1998
• Subjects: Air pollution; Applied sciences; Atmospheric pollution; Chemistry; Combustion and energy production; Emissions; Exact sciences and technology; Incineration; Pollution; Prevention and purification methods; Reaction inhibitor; Pilot plant; Heat treatment; Waste treatment; Pollution prevention; Urban waste; Pollutant creation; Gas injection; Polycyclic aromatic compound; Oxygen heterocycle; Pollutant emission; Sulfur dioxide; Ammonia; Incineration; Chlorine Organic compounds; Solid waste; Reaction mechanism; Air pollution; Physicochemical purification; Performance; Flue gas purification
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es9701265

Emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) from municipal waste incineration are currently a subject of considerable public concern because of their extreme toxicity. PCDD/F formation in incineration processes is being studied widely, but studies on inhibition are quite sparse, especially in a pilot-plant scale. In this work, the effect of four gaseous inhibitors (sulfur dioxide, ammonia, dimethylamine, and methyl mercaptan) on PCDD/PCDF formation in the combustion of liquid fuel was studied using a pilot-scale plant. The inhibitors were injected into the flue gas stream after the first economizer at a temperature of 670 °C and just before the second economizer at 410 °C. Both the chlorophenol and PCDD and PCDF concentrations decreased when inhibitors were added. Particle-phase PCDD/F concentrations in particular decreased by up to 98%. The results suggest that the formation of PCDD/Fs is hindered in the particle phase at the early stages of the PCDD/F formation chain, probably even before precursors such as chlorophenols have been formed.