Dioxins formation in salt-laden power boilers: A mass balance

Luthe, C. E.; Karidio, Ibrahim; Uloth, V. C.

doi:10.1016/s0045-6535(97)00356-1

Cited by 14 publications

(13 citation statements)

References 4 publications

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“…The hog fuel burned in the power boiler at Port Alberni contains sodium chloride absorbed from the seawater during transportation and storage of logs. Combustion of salty hog fuel is known to produce trace levels of dioxins and furans [5,6]. This was confirmed by stack tests and ash sample analyses for this BFB boiler.…”

Section: Confidential To Paprican Member Companies Prr 1625 • Decembesupporting

confidence: 70%

Combustion and Emission Performance of a Hog Fuel Fluidized Bed Boiler With Addition of Tire Derived Fuel

Duo¹,

Karidio²,

Cross

et al. 2006

Journal of Energy Resources Technology

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Salt-laden hog fuel (wood waste) is burnt in a fluidized bed boiler converted from a traveling grate boiler to generate steam for a specialty paper mill. The converted boiler has a design capacity of 156t∕h of steam from hog and actual generation has varied from 76% to 107% of the design capacity. The conversion has resulted in more stable operation, more complete combustion, less ash production, reduced boiler maintenance, and lower fossil fuel consumption. Tire derived fuel (TDF) is used as a supplementary fuel. With an energy content of 31GJ∕t for TDF, as compared to 8GJ∕t for wet hog, addition of 2%–5% TDF by weight increased the bed temperature by an average of 55°C, stabilized and improved the combustion of low quality hog and high moisture content sludge. The impact of TDF addition was studied in detail. Stack emissions were tested and bottom and flyash samples were analyzed. Although TDF contains an average of 1.6% zinc and 9.2% steel wire by weight, addition of TDF did not affect total particulate emissions from the boiler. SO2 emissions were increased due to the high sulfur content of TDF (1.4%), while NOx emissions were reduced. A good correlation was obtained from the test results, showing that the addition of TDF resulted in a reduction in both the total formation and the stack emissions of dioxins and furans.

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Section: Confidential To Paprican Member Companies Prr 1625 • Decembesupporting

confidence: 70%

Combustion and Emission Performance of a Hog Fuel Fluidized Bed Boiler With Addition of Tire Derived Fuel

Duo¹,

Karidio²,

Cross

et al. 2006

Journal of Energy Resources Technology

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“…In the post combustion zones, like ESP and baghouse filters, de novo synthesis involves catalyzed chlorination of carbonaceous structures present in fly ashes, between 250-500 • C or higher, with a peak at 300 • C, Cu being the more relevant catalyzer [111,[119][120][121][122][123]. Studies on combustion of salty laden wood revealed that 99% of total PCDD/Fs were associated to cyclone and ESP fly ashes, and their main formation was suggested to be de novo synthesis over fly ashes [124]. Tests performed between 260-430 • C, revealed that PCDD/Fs formation decreases for lower temperatures and shorter residence times [125,126].…”

Section: Origin Generation and Fate Of Pcdd/fs And Pahs In Combustion Processesmentioning

confidence: 99%

Insights into PCDD/Fs and PAHs in Biomass Boilers Envisaging Risks of Ash Use as Fertilizers

Lopes

Proença

2020

Applied Sciences

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Since ashes are a possible source of Persistent Organic Pollutants (POPs) contamination, their application in soils must be subject to more study and control. In this scope, feed residual forest biomasses and biomass ashes, collected along one year in four biomass power stations, were characterized mainly for their polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and Polycyclic Aromatic Hydrocarbons (PAHs) contents. The biomasses present concerning levels of Cl (0.04–0.28%) that may lead to PCDD/Fs formation. The biomasses also contain OCDD (29–260 ng/kg) and 1,2,3,4,6,7,8-HpCDD (35 ng/kg) that may contribute to increased Toxic Equivalents (TEQs) of ashes, possibly involving dichlorination and ash enrichment mechanisms. While the World Health Organization (WHO)2005-TEQs in bottom ashes (14–20 ng TEQ/kg) reaches the proposed limit (20 ng TEQ/kg) for ash use as fertilizers, in fly ashes (35–1139 ng TEQ/kg) the limit is exceeded. PAHs are below 0.02 mg/kg in bottom ashes and 1.5–2.5 mg/kg in fly ashes, complying with the proposed limit of 6 mg/kg. As bottom and fly ash streams may contain different ash flows, a clear definition of ash mixes is required. Correlations between unburned carbon (C), PAHs and PCDD/Fs were not found, which highlights the need for compulsory PCDD/Fs analysis in ashes, independently of their origin, burnout degree or levels of other contaminants. A sensitivity analysis was performed to evaluate the impact of handling non-detected values, which showed more impact for TEQs values close to the proposed regulatory limit of PCDD/Fs. These findings highlight the need to define reporting protocols of analytical results for risk assessments and conformity evaluation.

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“…Wunderli et al (2000) reported the solid residues from the incineration of native wood are below 10 ng I-TEQ/kg. Nevertheless, the fly ashes from the cyclone of the salt-laden wood steam boilers could reach 97.8-20900 ng I-TEQ/kg (Luthe et al, 1998). The degree of carbon burnout (Wunderli et al, 2000), contamination levels (chlorine, copper and chlorinated organics contents) in the feeding wood (Tame et al, 2007), combustion conditions and temperature trends of the flue gases are influential factors affecting the PCDD/F contents in the ashes.…”

Section: Pcdd/f Contents (Concentrations) In the Feeding Woodchips Amentioning

confidence: 99%

“…Generally speaking, three kinds of wood have been investigated for their emitted PCDD/F characteristics during power or heat productions (Wunderli et al, 2000), including waste wood (wood from construction activities and house demolition, impregnated wood and salt-laden wood) (Luthe et al, 1998;Wunderli et al, 2000), residual wood products (wood products which have been processed such as chipboard and wood dust from machining) (Sinkkonen et al, 1995) and nature wood (wood without any treatment, including saw dust, shavings and bark) (Schatowitz et al, 1994;Wunderli et al, 2000). Waste and residual wood often containing various types of contaminants such as chromated copper arsenate, pentachlorophenol, creosote, adhesives, paint, PVC and other surface coatings, could lead to higher emissions of PCDD/Fs, PAHs and metals (Lavric et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…The solid residues (bottom residues and fly ashes) from wood combustion can be reutilized as soil improvement material, in construction of roads and as supplementary material such as concrete production or filler material or must be disposed of in waste dumps (Sinkkonen et al, 1995;Wunderli et al, 2000). PCDD/F contents in the multicyclone ashes of the salt-laden wood steam boilers could range from 0.0978 to 20.9 ng I-TEQ/g (Luthe et al, 1998). Consequently, PCDD/F contents in the ashes from wood combustions must be evaluated before further considering their reutilizations.…”

Section: Introductionmentioning

confidence: 99%

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Fate and Distribution of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in a Woodchip-fuelled Boiler

Chen

Shen

Hsieh

et al. 2011

Aerosol Air Qual. Res.

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As yet, very little is known about the PCDD/F fate and distribution in the woodchip-fuelled boilers. In this study, the feeding woodchips, stack flue gases and the ashes in different units of a woodchip-fuelled boiler are sampled to investigate their PCDD/F characteristics. The PCDD/F contents in the bottom residues and fly ashes ranged from 18.9 to 66.3 ng I-TEQ/kg, which are below the Taiwanese PCDD/F regulation for reutilization of bottom residues, but still higher than PCDD/F limitations on soils for agricultural use (10 ng I-TEQ/kg), which are adopted by several countries. From the PCDD/F output/input ratios, we found that combustion of woodchips in the boiler system is more favourable for the formations of PCDFs by de novo syntheses, especially for lower chlorinated PCDF congeners. Although about half of the input PCDD/Fs mass are destroyed in the combustion, the output PCDD/Fs toxicity are 6.9 times higher than the inputs. Fly ashes exhibited the highest PCDD/F distributions among the woodchip-fuelled boiler. Still 21.4% of total PCDD/F mass and 18.0% of total PCDD/F toxicity were emitted from the stack flue gases due to the lack of control devices for gaseous phase PCDD/Fs. Decreasing de novo syntheses among the boiler systems, deploying control devices for gaseous phase PCDD/Fs, and proper management on the reutilization of fly ashes will ensure woodchip-fuelled boilers as a sustainable and renewable biomass energy.

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Dioxins formation in salt-laden power boilers: A mass balance

Cited by 14 publications

References 4 publications

Combustion and Emission Performance of a Hog Fuel Fluidized Bed Boiler With Addition of Tire Derived Fuel

Combustion and Emission Performance of a Hog Fuel Fluidized Bed Boiler With Addition of Tire Derived Fuel

Insights into PCDD/Fs and PAHs in Biomass Boilers Envisaging Risks of Ash Use as Fertilizers

Fate and Distribution of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in a Woodchip-fuelled Boiler

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