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Title: NICKEL SPECIES EMISSION INVENTORY FOR OIL-FIRED BOILERS

Abstract

Representative duplicate fly ash samples were obtained from the stacks of 400-MW and 385-MW utility boilers (Unit A and Unit B, respectively) using a modified U.S. Environmental Protection Agency (EPA) Method 17 sampling train assembly as they burned .0.9 and 0.3 wt% S residual oils, respectively, during routine power plant operations. Residual oil fly ash (ROFA) samples were analyzed for nickel (Ni) concentrations and speciation using inductively coupled plasma-atomic emission spectroscopy, x-ray absorption fine structure (XAFS) spectroscopy, x-ray diffraction (XRD), and a water-soluble Ni extraction method. ROFA water extraction residues were also analyzed for Ni speciation using XAFS and XRD. Total Ni concentrations in the ROFAs were similar, ranging from 1.3 to 1.5 wt%; however, stack gas Ni concentrations in the Unit A were {approx}990 {micro}g/Nm{sup 3} compared to {approx}620 {micro}g/Nm{sup 3} for Unit B because of the greater residual oil feed rates employed at Unit A to attain higher load (i.e., MW) conditions with a lower heating value oil. Ni speciation analysis results indicate that ROFAs from Unit A contain about 3 wt% NiSO{sub 4} {center_dot} xH{sub 2}O (where x is assumed to be 6 for calculation purposes) and a Ni-containing spinel compound, similar in composition to (Mg,Ni)(Al,Fe){sub 2}O{submore » 4}. ROFAs from Unit B contain on average 2.0 wt% NiSO{sub 4} {center_dot} 6H{sub 2}O and 1.1 wt% NiO. XAFS and XRD analyses did not detect any nickel sulfide compounds, including nickel subsulfide (Ni{sub 3}S{sub 2}) (XAFS detection limit is 5% of the total Ni concentration). In addition, XAFS measurements indicated that inorganic sulfate and organic thiophene species account for >97% of the total sulfur in the ROFAs. The presence of NiSO{sub 4} {center_dot} xH{sub 2}O and nickel oxide compound mixtures and lack of carcinogenic Ni{sub 3}S{sub 2} or nickel sulfide compounds (e.g., NiS, NiS{sub 2}) in ROFAs stack-sampled from 400- and 385-MW boilers are contrary to EPA's Ni inhalation cancer risk assessment (''Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units--Final Report to Congress'', February 1998), where it is assumed that the Ni compound mixture emitted from oil-fired utilities is 50% as carcinogenic as Ni{sub 3}S{sub 2}. Apparently, this assumption greatly overestimates the Ni inhalation cancer risk from oil-fired utilities.« less

Authors:
; ; ;
Publication Date:
Research Org.:
University of North Dakota (US)
Sponsoring Org.:
(US)
OSTI Identifier:
823621
DOE Contract Number:  
FC26-98FT40321
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Jan 2004
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; BOILERS; EMISSION SPECTROSCOPY; FINE STRUCTURE; FLY ASH; NEOPLASMS; NICKEL; NICKEL OXIDES; NICKEL SULFIDES; PETROLEUM RESIDUES; POWER PLANTS; RISK ASSESSMENT; SENSITIVITY; US EPA; X-RAY DIFFRACTION

Citation Formats

Galbreath, Kevin C, Schulz, Richard L, Toman, Donald L, and Nyberg, Carolyn M. NICKEL SPECIES EMISSION INVENTORY FOR OIL-FIRED BOILERS. United States: N. p., 2004. Web. doi:10.2172/823621.
Galbreath, Kevin C, Schulz, Richard L, Toman, Donald L, & Nyberg, Carolyn M. NICKEL SPECIES EMISSION INVENTORY FOR OIL-FIRED BOILERS. United States. doi:10.2172/823621.
Galbreath, Kevin C, Schulz, Richard L, Toman, Donald L, and Nyberg, Carolyn M. Thu . "NICKEL SPECIES EMISSION INVENTORY FOR OIL-FIRED BOILERS". United States. doi:10.2172/823621. https://www.osti.gov/servlets/purl/823621.
@article{osti_823621,
title = {NICKEL SPECIES EMISSION INVENTORY FOR OIL-FIRED BOILERS},
author = {Galbreath, Kevin C and Schulz, Richard L and Toman, Donald L and Nyberg, Carolyn M},
abstractNote = {Representative duplicate fly ash samples were obtained from the stacks of 400-MW and 385-MW utility boilers (Unit A and Unit B, respectively) using a modified U.S. Environmental Protection Agency (EPA) Method 17 sampling train assembly as they burned .0.9 and 0.3 wt% S residual oils, respectively, during routine power plant operations. Residual oil fly ash (ROFA) samples were analyzed for nickel (Ni) concentrations and speciation using inductively coupled plasma-atomic emission spectroscopy, x-ray absorption fine structure (XAFS) spectroscopy, x-ray diffraction (XRD), and a water-soluble Ni extraction method. ROFA water extraction residues were also analyzed for Ni speciation using XAFS and XRD. Total Ni concentrations in the ROFAs were similar, ranging from 1.3 to 1.5 wt%; however, stack gas Ni concentrations in the Unit A were {approx}990 {micro}g/Nm{sup 3} compared to {approx}620 {micro}g/Nm{sup 3} for Unit B because of the greater residual oil feed rates employed at Unit A to attain higher load (i.e., MW) conditions with a lower heating value oil. Ni speciation analysis results indicate that ROFAs from Unit A contain about 3 wt% NiSO{sub 4} {center_dot} xH{sub 2}O (where x is assumed to be 6 for calculation purposes) and a Ni-containing spinel compound, similar in composition to (Mg,Ni)(Al,Fe){sub 2}O{sub 4}. ROFAs from Unit B contain on average 2.0 wt% NiSO{sub 4} {center_dot} 6H{sub 2}O and 1.1 wt% NiO. XAFS and XRD analyses did not detect any nickel sulfide compounds, including nickel subsulfide (Ni{sub 3}S{sub 2}) (XAFS detection limit is 5% of the total Ni concentration). In addition, XAFS measurements indicated that inorganic sulfate and organic thiophene species account for >97% of the total sulfur in the ROFAs. The presence of NiSO{sub 4} {center_dot} xH{sub 2}O and nickel oxide compound mixtures and lack of carcinogenic Ni{sub 3}S{sub 2} or nickel sulfide compounds (e.g., NiS, NiS{sub 2}) in ROFAs stack-sampled from 400- and 385-MW boilers are contrary to EPA's Ni inhalation cancer risk assessment (''Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units--Final Report to Congress'', February 1998), where it is assumed that the Ni compound mixture emitted from oil-fired utilities is 50% as carcinogenic as Ni{sub 3}S{sub 2}. Apparently, this assumption greatly overestimates the Ni inhalation cancer risk from oil-fired utilities.},
doi = {10.2172/823621},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {1}
}