Towards controlling PCDD/F production in a multi-fuel fired BFB boiler using two sulfur addition strategies: Part II: Thermodynamic analysis

Cyril Bajamundi (Corresponding Author), Pasi Vainikka, M. Hedman, J. Konttinen

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

A staged equilibrium process model was developed for a bubbling fluidized bed boiler firing SRF, bark and sludge. The model was used to study the influence of sulfur addition strategies (S-pellet additive and peat co-firing) on the behavior of copper, bromine, and alkalis. Aerosol samples collected from the backpass of the boiler were used to validate the chemistry predicted by the model. The model revealed that Cu existed as Cu2S(s3) in the reducing zone, and CuCl(g) (for all test cases) and CuO(s) (during peat co-firing) in the oxidation zones. CuBr3(g) was also present after the introduction of tertiary air. However the model failed to predict the formation of CuSO4, an important passive species of Cu necessary for PCDD/F abatement. The modes of occurrence of Cu were classified as either active or passive with respect to de novo synthesis and an active/passive species molar ratio (APR) was introduced. APR showed high correlation with the PCDD/F production levels. Sensitivity analysis revealed that excessive Cu in the fuel mixture decreased the volatility of the element due to the formation of CuO(s). Simulation for peat co-firing with low Cu content showed that PCDD/F concentration is decreased and is comparable to that of S-pellet addition. Sensitivity analysis revealed that increasing the energy share of sludge can likewise lower PCDD/F production.
Original languageEnglish
Pages (from-to)688-697
Number of pages10
JournalFuel
Volume134
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Fingerprint

Sulfur
Boilers
Thermodynamics
Peat
Sensitivity analysis
Boiler firing
Bromine
Alkalies
Aerosols
Fluidized beds
Copper
Oxidation
Air

Keywords

  • fluidized bed boilers
  • staged equilibrium modeling
  • sulfur addition
  • copper
  • PCDD/F
  • pellets
  • peat
  • combustion

Cite this

Bajamundi, Cyril ; Vainikka, Pasi ; Hedman, M. ; Konttinen, J. / Towards controlling PCDD/F production in a multi-fuel fired BFB boiler using two sulfur addition strategies : Part II: Thermodynamic analysis. In: Fuel. 2014 ; Vol. 134. pp. 688-697.
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title = "Towards controlling PCDD/F production in a multi-fuel fired BFB boiler using two sulfur addition strategies: Part II: Thermodynamic analysis",
abstract = "A staged equilibrium process model was developed for a bubbling fluidized bed boiler firing SRF, bark and sludge. The model was used to study the influence of sulfur addition strategies (S-pellet additive and peat co-firing) on the behavior of copper, bromine, and alkalis. Aerosol samples collected from the backpass of the boiler were used to validate the chemistry predicted by the model. The model revealed that Cu existed as Cu2S(s3) in the reducing zone, and CuCl(g) (for all test cases) and CuO(s) (during peat co-firing) in the oxidation zones. CuBr3(g) was also present after the introduction of tertiary air. However the model failed to predict the formation of CuSO4, an important passive species of Cu necessary for PCDD/F abatement. The modes of occurrence of Cu were classified as either active or passive with respect to de novo synthesis and an active/passive species molar ratio (APR) was introduced. APR showed high correlation with the PCDD/F production levels. Sensitivity analysis revealed that excessive Cu in the fuel mixture decreased the volatility of the element due to the formation of CuO(s). Simulation for peat co-firing with low Cu content showed that PCDD/F concentration is decreased and is comparable to that of S-pellet addition. Sensitivity analysis revealed that increasing the energy share of sludge can likewise lower PCDD/F production.",
keywords = "fluidized bed boilers, staged equilibrium modeling, sulfur addition, copper, PCDD/F, pellets, peat, combustion",
author = "Cyril Bajamundi and Pasi Vainikka and M. Hedman and J. Konttinen",
year = "2014",
doi = "10.1016/j.fuel.2014.05.033",
language = "English",
volume = "134",
pages = "688--697",
journal = "Fuel",
issn = "0016-2361",
publisher = "Elsevier",

}

Towards controlling PCDD/F production in a multi-fuel fired BFB boiler using two sulfur addition strategies : Part II: Thermodynamic analysis. / Bajamundi, Cyril (Corresponding Author); Vainikka, Pasi; Hedman, M.; Konttinen, J.

In: Fuel, Vol. 134, 2014, p. 688-697.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Towards controlling PCDD/F production in a multi-fuel fired BFB boiler using two sulfur addition strategies

T2 - Part II: Thermodynamic analysis

AU - Bajamundi, Cyril

AU - Vainikka, Pasi

AU - Hedman, M.

AU - Konttinen, J.

PY - 2014

Y1 - 2014

N2 - A staged equilibrium process model was developed for a bubbling fluidized bed boiler firing SRF, bark and sludge. The model was used to study the influence of sulfur addition strategies (S-pellet additive and peat co-firing) on the behavior of copper, bromine, and alkalis. Aerosol samples collected from the backpass of the boiler were used to validate the chemistry predicted by the model. The model revealed that Cu existed as Cu2S(s3) in the reducing zone, and CuCl(g) (for all test cases) and CuO(s) (during peat co-firing) in the oxidation zones. CuBr3(g) was also present after the introduction of tertiary air. However the model failed to predict the formation of CuSO4, an important passive species of Cu necessary for PCDD/F abatement. The modes of occurrence of Cu were classified as either active or passive with respect to de novo synthesis and an active/passive species molar ratio (APR) was introduced. APR showed high correlation with the PCDD/F production levels. Sensitivity analysis revealed that excessive Cu in the fuel mixture decreased the volatility of the element due to the formation of CuO(s). Simulation for peat co-firing with low Cu content showed that PCDD/F concentration is decreased and is comparable to that of S-pellet addition. Sensitivity analysis revealed that increasing the energy share of sludge can likewise lower PCDD/F production.

AB - A staged equilibrium process model was developed for a bubbling fluidized bed boiler firing SRF, bark and sludge. The model was used to study the influence of sulfur addition strategies (S-pellet additive and peat co-firing) on the behavior of copper, bromine, and alkalis. Aerosol samples collected from the backpass of the boiler were used to validate the chemistry predicted by the model. The model revealed that Cu existed as Cu2S(s3) in the reducing zone, and CuCl(g) (for all test cases) and CuO(s) (during peat co-firing) in the oxidation zones. CuBr3(g) was also present after the introduction of tertiary air. However the model failed to predict the formation of CuSO4, an important passive species of Cu necessary for PCDD/F abatement. The modes of occurrence of Cu were classified as either active or passive with respect to de novo synthesis and an active/passive species molar ratio (APR) was introduced. APR showed high correlation with the PCDD/F production levels. Sensitivity analysis revealed that excessive Cu in the fuel mixture decreased the volatility of the element due to the formation of CuO(s). Simulation for peat co-firing with low Cu content showed that PCDD/F concentration is decreased and is comparable to that of S-pellet addition. Sensitivity analysis revealed that increasing the energy share of sludge can likewise lower PCDD/F production.

KW - fluidized bed boilers

KW - staged equilibrium modeling

KW - sulfur addition

KW - copper

KW - PCDD/F

KW - pellets

KW - peat

KW - combustion

U2 - 10.1016/j.fuel.2014.05.033

DO - 10.1016/j.fuel.2014.05.033

M3 - Article

VL - 134

SP - 688

EP - 697

JO - Fuel

JF - Fuel

SN - 0016-2361

ER -