Simulation of the reduction of nitrogen species in air jets

E. Vainio, A. Brink, M. Hupa, Hannu Vesala, Tuula Kajolinna

Research output: Contribution to conferenceConference articleScientific

Abstract

The reduction of nitrogen species to N2 in the air jets in an industrial bubbling fluidized bed boiler was modelled using detailed gas phase kinetics and compared to in-furnace measurement data. The stack measurement of the boiler showed over 90% of reduction of nitrogen species, although only air staging was applied. The measurements revealed that most of the reduction occurred over the secondary air jet level. The reduction of nitrogen species in the secondary and the tertiary air jets were studied using the CHEMKIN software and a detailed reaction mechanism. Different mixing approaches in the modelling were tested: direct mixing, gradual mixing, inverse mixing using PFRs, and also PSRs were used to describe the jets. The simulations with gradual mixing were carried out by using plug flow reactors to describe the jets and the mixing of the bulk gas into the jets. The residence time, the entrainment of gas into the air jet, and the temperature in the different reactors were based on a CFD simulation of a single jet. The residence time in all simulations were based on the CFD simulation. Direct mixing of the air jet and bulk gas using PFRs showed the poorest agreement. The speciation and reduction of reactive nitrogen species was in best agreement with the measurements when using the gradual dilution of the air jet with the bulk flow approach.
Original languageFinnish
Publication statusPublished - 2013
MoE publication typeNot Eligible
EventFinnish-Swedish Flame Days 2013 - Jyväskylä, Finland
Duration: 17 Apr 201318 Apr 2013

Conference

ConferenceFinnish-Swedish Flame Days 2013
CountryFinland
CityJyväskylä
Period17/04/1318/04/13

Keywords

  • air-staging
  • nox
  • simulations

Cite this

Vainio, E., Brink, A., Hupa, M., Vesala, H., & Kajolinna, T. (2013). Simulation of the reduction of nitrogen species in air jets. Paper presented at Finnish-Swedish Flame Days 2013, Jyväskylä, Finland.
Vainio, E. ; Brink, A. ; Hupa, M. ; Vesala, Hannu ; Kajolinna, Tuula. / Simulation of the reduction of nitrogen species in air jets. Paper presented at Finnish-Swedish Flame Days 2013, Jyväskylä, Finland.
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title = "Simulation of the reduction of nitrogen species in air jets",
abstract = "The reduction of nitrogen species to N2 in the air jets in an industrial bubbling fluidized bed boiler was modelled using detailed gas phase kinetics and compared to in-furnace measurement data. The stack measurement of the boiler showed over 90{\%} of reduction of nitrogen species, although only air staging was applied. The measurements revealed that most of the reduction occurred over the secondary air jet level. The reduction of nitrogen species in the secondary and the tertiary air jets were studied using the CHEMKIN software and a detailed reaction mechanism. Different mixing approaches in the modelling were tested: direct mixing, gradual mixing, inverse mixing using PFRs, and also PSRs were used to describe the jets. The simulations with gradual mixing were carried out by using plug flow reactors to describe the jets and the mixing of the bulk gas into the jets. The residence time, the entrainment of gas into the air jet, and the temperature in the different reactors were based on a CFD simulation of a single jet. The residence time in all simulations were based on the CFD simulation. Direct mixing of the air jet and bulk gas using PFRs showed the poorest agreement. The speciation and reduction of reactive nitrogen species was in best agreement with the measurements when using the gradual dilution of the air jet with the bulk flow approach.",
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language = "Finnish",
note = "null ; Conference date: 17-04-2013 Through 18-04-2013",

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Vainio, E, Brink, A, Hupa, M, Vesala, H & Kajolinna, T 2013, 'Simulation of the reduction of nitrogen species in air jets' Paper presented at Finnish-Swedish Flame Days 2013, Jyväskylä, Finland, 17/04/13 - 18/04/13, .

Simulation of the reduction of nitrogen species in air jets. / Vainio, E.; Brink, A.; Hupa, M.; Vesala, Hannu; Kajolinna, Tuula.

2013. Paper presented at Finnish-Swedish Flame Days 2013, Jyväskylä, Finland.

Research output: Contribution to conferenceConference articleScientific

TY - CONF

T1 - Simulation of the reduction of nitrogen species in air jets

AU - Vainio, E.

AU - Brink, A.

AU - Hupa, M.

AU - Vesala, Hannu

AU - Kajolinna, Tuula

PY - 2013

Y1 - 2013

N2 - The reduction of nitrogen species to N2 in the air jets in an industrial bubbling fluidized bed boiler was modelled using detailed gas phase kinetics and compared to in-furnace measurement data. The stack measurement of the boiler showed over 90% of reduction of nitrogen species, although only air staging was applied. The measurements revealed that most of the reduction occurred over the secondary air jet level. The reduction of nitrogen species in the secondary and the tertiary air jets were studied using the CHEMKIN software and a detailed reaction mechanism. Different mixing approaches in the modelling were tested: direct mixing, gradual mixing, inverse mixing using PFRs, and also PSRs were used to describe the jets. The simulations with gradual mixing were carried out by using plug flow reactors to describe the jets and the mixing of the bulk gas into the jets. The residence time, the entrainment of gas into the air jet, and the temperature in the different reactors were based on a CFD simulation of a single jet. The residence time in all simulations were based on the CFD simulation. Direct mixing of the air jet and bulk gas using PFRs showed the poorest agreement. The speciation and reduction of reactive nitrogen species was in best agreement with the measurements when using the gradual dilution of the air jet with the bulk flow approach.

AB - The reduction of nitrogen species to N2 in the air jets in an industrial bubbling fluidized bed boiler was modelled using detailed gas phase kinetics and compared to in-furnace measurement data. The stack measurement of the boiler showed over 90% of reduction of nitrogen species, although only air staging was applied. The measurements revealed that most of the reduction occurred over the secondary air jet level. The reduction of nitrogen species in the secondary and the tertiary air jets were studied using the CHEMKIN software and a detailed reaction mechanism. Different mixing approaches in the modelling were tested: direct mixing, gradual mixing, inverse mixing using PFRs, and also PSRs were used to describe the jets. The simulations with gradual mixing were carried out by using plug flow reactors to describe the jets and the mixing of the bulk gas into the jets. The residence time, the entrainment of gas into the air jet, and the temperature in the different reactors were based on a CFD simulation of a single jet. The residence time in all simulations were based on the CFD simulation. Direct mixing of the air jet and bulk gas using PFRs showed the poorest agreement. The speciation and reduction of reactive nitrogen species was in best agreement with the measurements when using the gradual dilution of the air jet with the bulk flow approach.

KW - air-staging

KW - nox

KW - simulations

M3 - Conference article

ER -

Vainio E, Brink A, Hupa M, Vesala H, Kajolinna T. Simulation of the reduction of nitrogen species in air jets. 2013. Paper presented at Finnish-Swedish Flame Days 2013, Jyväskylä, Finland.