Polycyclic aromatic hydrocarbon (PAH) emissions from a coal-fired pilot FBC system

Kunlei Liu, Wenjun Han, Wei Ping Pan, John T. Riley

Research output: Contribution to journalArticlepeer-review

116 Scopus citations

Abstract

Due to the extensive amount of data suggesting the hazards of these compounds, 16 polycyclic aromatic hydrocarbons (PAHs) are on the Environmental Protection Agency (EPA) Priority Pollutant List. Emissions of these PAHs in the flue gas from the combustion of four coals were measured during four 1000h combustion runs using the 0.1MW heat-input (MWth) bench-scale fluidized bed combustor (FBC). An on-line sampling system was designed for the 16 PAHs, which consisted of a glass wool filter, condenser, glass fiber filter, Teflon filter, and a Tenax trap. The filters and Tenax were extracted by methylene chloride and hexane, respectively, followed by GC/MS analysis using the selective ion monitoring (SIM) mode. In this project, the effects of operating parameters, limestone addition, chlorine content in the coal, and Ca/S molar ratio on the emissions of PAHs were studied. The results indicated that the emissions of PAHs in an FBC system are primarily dependent on the combustion temperature and excess air ratio. The injection of secondary air with high velocity in the freeboard effectively reduces PAH emissions. The addition of extra limestone can promote the formation of PAHs in the FBC system. Chlorine in the coal can possibly lead to large benzene ring PAH formation during combustion. The total PAH emission increases with an increase in the sulfur content of coal. Incomplete combustion results in PAHs with four or more benzene rings. High efficiency combustion results in PAHs with two or three benzene rings.

Original languageEnglish
Pages (from-to)175-188
Number of pages14
JournalJournal of Hazardous Materials
Volume84
Issue number2-3
DOIs
StatePublished - Jun 29 2001

Bibliographical note

Funding Information:
The authors are grateful for the financial support received for this project through EPRI and the Illinois Clean Coal Institute, and for the guidance of the project managers from EPRI (Dr. A.K. Mehta) and the Illinois Clean Coal Institute (Dr. K.K. Ho).

Keywords

  • Combustion
  • Fluidized bed
  • GC/MS
  • PAHs

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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