title: Speciation, behaviour, and fate of mercury under oxy-fuel combustion conditions.
abstract: The work presented here reports the first study in which the speciation, behaviour and fate of mercury (Hg) have been evaluated under oxy-fuel combustion at the largest oxy-Pulverised Coal Combustion (oxy-PCC) demonstration plant to date during routine operating conditions and partial exhaust flue gas re-circulation to the boiler. The effect of the CO2-rich flue gas re-circulation on Hg has also been evaluated. Results reveal that oxy-PCC operational conditions play a significant role on Hg partitioning and fate because of the continuous CO2-rich flue gas re-circulations to the boiler. Mercury escapes from the cyclone in a gaseous form as Hg(2+) (68%) and it is the prevalent form in the CO2-rich exhaust flue gas (99%) with lower proportions of Hg(0) (1.3%). The overall retention rate for gaseous Hg is around 12%; Hg(0) is more prone to be retained (95%) while Hg(2+) shows a negative efficiency capture for the whole installation. The negative Hg(2+) capture efficiencies are due to the continuous CO2-rich exhaust flue gas recirculation to the boiler with enhanced Hg contents. Calculations revealed that 44mg of Hg were re-circulated to the boiler as a result of 2183 re-circulations of CO2-rich flue gas. Especial attention must be paid to the role of the CO2-rich exhaust flue gas re-circulation to the boiler on the Hg enrichment in Fly Ashes (FAs).
authors.affiliation: Centre for Innovation on Carbon Capture and Storage (CICCS), Institute of Mechanical, Process and Energy Engineering (IMPEE), Heriot-Watt University, EH14 4AS, United Kingdom. Electronic address: pc247@hw.ac.uk.
authors.forename: Patricia
authors.initials: P
authors.lastname: Córdoba
authors.affiliation: Centre for Innovation on Carbon Capture and Storage (CICCS), Institute of Mechanical, Process and Energy Engineering (IMPEE), Heriot-Watt University, EH14 4AS, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Maroto-Valer
authors.affiliation: Fundacion Ciudad de la Energia (CIUDEN), Avenida Segunda, No 2 (Compostilla), 24004 Ponferrada (León), Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Delgado
authors.affiliation: Fundacion Ciudad de la Energia (CIUDEN), Avenida Segunda, No 2 (Compostilla), 24004 Ponferrada (León), Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Diego
authors.affiliation: Institute of Environmental Assessment and Water Research (IDÆA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain.
authors.forename: Oriol
authors.initials: O
authors.lastname: Font
authors.affiliation: Institute of Environmental Assessment and Water Research (IDÆA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Querol
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D004867:Equipment Design; D005390:Fires; D005740:Gases / Q000032:analysis / Q000302:isolation & purification; D008628:Mercury / Q000032:analysis*; D010100:Oxygen / Q000737:chemistry*; D011210:Power Plants / Q000295:instrumentation
chemical_list: D000393:Air Pollutants; D005740:Gases; D008628:Mercury; D010100:Oxygen
keywords: CO(2)-rich flue gas re-circulation; Capture efficiencies; FAs; Mercury; Oxy-PCC