Neurocomputing approach for the prediction of NOx emissions from CFBC in air-fired and oxygen-enriched atmospheres

Jarosław Krzywański, Wojciech Nowak


This paper presents a way of predicting NOx emissions from circulating fluidized bed combustors (CFBC) in air-fired and oxyfuel
conditions, using the Artificial Neural Network (ANN) Approach. The Original Neural Networks Model was successfully
applied to calculate the NOx (i.e. NO + NO2) emissions from coal combustion under air-fired and oxygen-enriched conditions
in several CFB boilers. The ANN model was shown to give quick and accurate results in response to the input pattern. The
NOx emissions, evaluated using the developed ANN model are in good agreement with the experimental results.


Nitrogen oxides; Circulating fluidized bed; Oxy combustion; Artificial neural networks

Full Text:



National Center for Environmental Assessment-RTP Division, Office of

Research and Development, U.S. Environmental Protection Agency,

Research Triangle Park, EPA/600/R-08/082F. Integrated Science Assessment

for Oxides of Nitrogen - Health Criteria (2008).

L. Amand, B. Leckner, K. Dam-Johansen, Influence of SO2 on the

NO/N2O chemistry in fluidized bed combustion: 1. full-scale experiments,

Fuel 72 (1993) 557–564.

L.-E. Åmand, B. Leckner, Influence of fuel on the emission of nitrogen

oxides (NO and N2O) from an 8-MW fluidized bed boiler, Combustion

and Flame 84 (1-2) (1991) 181–196.

L. Amand, B. Leckner, The role of fuel volatiles for the emission of

nitrogen oxides from fluidized bed boilers - a comparison between designs,

in: Proc. of the 23rd International Symposium on Combustion,

, pp. 927–933.

P. Basu, Combustion of coal in circulating fluidized-bed boilers: a review,

Chemical Engineering Science 54 (22) (1999) 5547–5557.

E. Bool, S. Laux, E. Eddings, Oxy-coal combustion in small-scale CFB,

in: Proc. Of th 35th International Technical Conference on Clean Coal

& Fuel Systems, Florida, USA, 2010, pp. 190–196.

T. Czakiert, W. Muskala, S. Jankowska, G. Krawczyk, P. Borecki, L. Jesionowski,

W. Nowak, The effect of oxygen concentration on nitrogen

conversion in oxy-fuel CFB environment, in: 21 International Conference

on fluidized bed combustion, Naples, Italy, 2012, pp. 495–502.

F. Luis, C. A. Londono, X. S. Wang, B. M. Gibbs, Influence of operating

parameters on nox and n2o axial profiles in a circulating fluidized bed

combustor, Fuel 75 (8) (1996) 971–978.

T. Eriksson, O. Sippu, A. Hotta, M. K. Zhen Fan, T. Hyppänen,

T. Pikkarainen, Oxyfuel CFB boiler as a route to near zero CO2 emission

coal firing, in: Power-GEN Europe, 2007, pp. 26–28.

B. Feng, H. Liu, J.-W. Yuan, Z.-J. Lin, D.-C. Liu, B. Leckner, Nitrogen

oxides emission from a circulating fluidized bed combustor, International

Journal of Energy Research 20 (11) (1996) 1015–1025.

A. Gungor, Prediction of so 2 and no x emissions for low-grade turkish

lignites in cfb combustors, Chemical Engineering Journal 146 (3)

(2009) 388–400.

A. Gungor, N. Eskin, Two-dimensional coal combustion modeling of

cfb, International Journal of Thermal Sciences 47 (2) (2008) 157–174.

A. Hayhurst, A. Lawrence, The amounts of nox and n2o formed in a

fluidized bed combustor during the burning of coal volatiles and also of

char, Combustion and flame 105 (3) (1996) 341–357.

L. Jia, Y. Tan, D. McCalden, Y. Wu, I. He, R. Symonds, E. Anthony,

Commissioning of a 0.8 mw th cfbc for oxy-fuel combustion, International

Journal of Greenhouse Gas Control 7 (2012) 240–243.

L. Jia, Y. Tan, Y. Wu, E. Anthony, Oxy-fuel combustion tests using a 0.8

mwth pilot-scale circulating fluidized bed, in: Proceedings of the 21st

International Conference on Fluidized Bed Combustion, Naples, Italy,

, pp. 381–388.

L. Jia, Y. Tan, E. Anthony, Emissions of so2 and no x during oxy- fuel

cfb combustion tests in a mini-circulating fluidized bed combustion reactor,

Energy & Fuels 24 (2) (2009) 910–915.

L. Jia, Y. Tan, C. Wang, E. Anthony, Experimental study of oxy-fuel

combustion and sulfur capture in a mini-cfbc, Energy & Fuels 21 (6)

(2007) 3160–3164.

T. Knöbig, J. Werther, L.-E. Åmand, B. Leckner, Comparison of largeand

small-scale circulating fluidized bed combustors with respect to

pollutant formation and reduction for different fuels, Fuel 77 (14) (1998)


B. Leckner, Fluidized bed combustion: mixing and pollutant limitation,

Progress in Energy and Combustion Science 24 (1) (1998) 31–61.

B. Leckner, L.-E. Åmand, K. Lücke, J. Werther, Gaseous emissions

from co-combustion of sewage sludge and coal/wood in a fluidized

bed, Fuel 83 (4) (2004) 477–486.

B. Leckner, A. Lyngfelt, Optimization of emissions from fluidized bed

combustion of coal, biofuel and waste, International journal of energy

research 26 (13) (2002) 1191–1202.

H. Liu, B. M. Gibbs, The influence of limestone addition at different

positions on gaseous emissions from a coal-fired circulating fluidized

bed combustor, Fuel 77 (14) (1998) 1569–1577.

M. Liukkonen, M. Heikkinen, T. Hiltunen, E. Hälikkä, R. Kuivalainen,

Y. Hiltunen, Artificial neural networks for analysis of process states in

fluidized bed combustion, Energy 36 (1) (2011) 339–347.

M. Liukkonen, T. Hiltunen, E. Hälikkä, Y. Hiltunen, Modeling of the

fluidized bed combustion process and no x emissions using selforganizing

maps: an application to the diagnosis of process states,

Environmental Modelling & Software 26 (5) (2011) 605–614.

D. Mao, J. R. Edwards, A. V. Kuznetsov, R. K. Srivastava, Threedimensional

numerical simulation of a circulating fluidized bed reactor

for multi-pollutant control, Chemical engineering science 59 (20) (2004) 4279–4289.

N. Nsakala, G. Liljedahl, D. Turek, Greenhouse gas emissions control

by oxygen firing in circulating fluidized bed boilers: Phase ii – pilot

scale testing and updated performance and economics for oxygen

fired CFB, Tech. rep., PPL Report No. PPL-04-CT-25 under cooperative

agreement No. DE-FC26-01NT41146 (2004).

G. Scheffknecht, L. Al-Makhadmeh, U. Schnell, J. Maier, Oxy-fuel

coal combustion—a review of the current state-of-the-art, International

Journal of Greenhouse Gas Control 5 (2011) S16–S35.

Y. Tan, L. Jia, Y. Wu, E. Anthony, Experiences and results on a 0.8

mwth oxy-fuel operation pilot-scale circulating fluidized bed, Applied

Energy 92 (2012) 343–347.

M. B. Toftegaard, J. Brix, P. A. Jensen, P. Glarborg, A. D. Jensen, Oxyfuel

combustion of solid fuels, Progress in energy and combustion science

(5) (2010) 581–625.

T. Klajny, J. Krzywanski, W. Nowak, Mechanism and kinetics of coal

combustion in oxygen enhanced conditions, in: 6th International Symposium

on Coal Combustion, Wuhan, China, 2007, pp. 148–153.

J. Zhao, C. Brereton, J. R. Grace, C. J. Lim, R. Legros, Gas concentration

profiles and NOx formation in circulating fluidized bed combustion,

Fuel 76 (9) (1997) 853–860.

L. Duan, C. Zhao, W. Zhou, C. Qu, X. Chen, O 2/co 2 coal combustion

characteristics in a 50kw th circulating fluidized bed, International

Journal of Greenhouse Gas Control 5 (4) (2011) 770–776.

T. Eriksson, K. Nuortimo, A. Hotta, K. Myöhänen, T. Hyppänen,

T. Pikkarainen, Near zero co2 emissions in coal firing with oxyfuel cfb

boiler, in: Proc. of the 9th International Conference on Circulating Fluidized

Beds, Hamburg, Germany, May, 2008, pp. 13–16.

A. Blaszczuk, W. Nowak, S. Jagodzik, Effects of operating conditions

on denox system efficiency in supercritical circulating fluidized bed

boiler, Journal of Power Technologies 93 (1) (2013) 1.

A. Blaszczuk, M. Komorowski, W. Nowak, Distribution of solids concentration

and temperature within combustion chamber of sc-otu cfb

boiler, Journal of Power Technologies 92 (1) (2012) 27–33.

B. Harris, J. Davidson, Modelling options for circulating fluidized beds:

a core/annulus deposition model, Circulating fluidized bed technology

IV (1994) 32.

J. Krzywa´ nski, T. Czakiert, W. Muskała, W. Nowak, Modelling of CO2,

CO, SO2, O2 and NOx emissions from the oxy-fuel combustion in a

circulating fluidized bed, Fuel Processing Technology 92 (3) (2011)


J. Krzywanski, T. Czakiert,W. Muskala, R. Sekret,W. Nowak, Modeling

of solid fuels combustion in oxygen-enriched atmosphere in circulating

fluidized bed boiler: Part 1. The mathematical model of fuel combustion

in oxygen-enriched CFB environment, Fuel Processing Technology

(3) (2010) 290–295.

J. Krzywanski, T. Czakiert, W. Muskala, R. Sekret, W. Nowak, Modeling

of solid fuel combustion in oxygen-enriched atmosphere in circulating

fluidized bed boiler: Part 2. Numerical simulations of heat transfer

and gaseous pollutant emissions associated with coal combustion in

O2/CO2 and O2/N2 atmospheres enriched with oxygen under circulating

fluidized bed conditions, Fuel Processing Technology 91 (3) (2010)


W. Muskała, J. Krzywi´ nski, R. Sekret, W. Nowak, Model research of

coal combustion in circulating fluidized bed boilers, Chemical and Process

Engineering 29 (2008) 473–492.

K. Myöhänen, T. Hyppänen, M. Loschkin, Converting measurement

data to process knowledge by using three-dimensional cfb furnace

model, in: The 8th International Conference on CFB, 2005.

D. Pallares, F. Johnsson, M. Palonen, A comprehensive model of cfb

combustion, in: 9th Int. Conf. on Circulating Fluidized Beds, 2008.

M. Palonen, D. Pallarès, A. Larsson, F. Johnsson, V. Ylä-Outinen,

J. Laine, Circulating fluidized bed combustion-build-up and validation

of a three-dimensional model.

T. Pikkarainen, A. Tourunen, H. Nevalainen, T. Leino, J. Saastamoinen,

T. Eriksson, Small scale fluidized bed experiments under oxygen combustion

conditions, in: International Conference on Coal Science &

Techology, University of Nottingham UK, 2007.

J. Saastamoinen, A. Tourunen, T. Pikkarainen, H. Häsä, J. Miettinen,

T. Hyppänen, K. Myöhänen, Fluidized bed combustion in high concentrations

of o2 and co2, in: 19th FBC Conference, 2006.

J. Werther, Fluid dynamics, temperature and concentration fields in

large-scale cfb combustors, in: 8-th International Conference on Circulating

Fluidized Beds, 2005.

N. Zhang, B. Lu, W. Wang, J. Li, 3D CFD simulation of combustion in

a 150 MWe circulating fluidized bed boiler, in: Proc. of the 10-th International

Conference on Circulating Fluidized Beds and Fluidization

Technology - CFB-10, Sunriver, Oregon, USA, 2011, pp. 537–544.

C. Zhao, W. Zhou, L. Duan, X. Chan, 2d Euler-Euler simulation of oxycoal

combustion in a circulating fluidized bed., in: Proc. of the 21 International

Conference on fluidized bed combustion, Naples, Italy, 2012,

pp. 495–502.

W. Zhou, C. Zhao, L. Duan, X. Chen, D. Liu, A simulation study of

coal combustion under o 2/co 2 and o 2/rfg atmospheres in circulating

fluidized bed, Chemical engineering journal 223 (2013) 816–823.

W. Zhou, C. Zhao, L. Duan, X. Chen, C. Liang, Two-dimensional computational

fluid dynamics simulation of nitrogen and sulfur oxides emissions

in a circulating fluidized bed combustor, Chemical engineering

journal 173 (2) (2011) 564–573.

W. Zhou, C. Zhao, L. Duan, D. Liu, X. Chen, Cfd modeling of oxycoal

combustion in circulating fluidized bed, International Journal of

Greenhouse Gas Control 5 (6) (2011) 1489–1497.

W. Zhou, C. Zhao, L. Duan, D. Liu, X. Chen, Simulation study of oxyfuel

combustion in a circulating fluidized bed, in: The 35th International

Technical Conference on Clean Coal & Fuel Systems, Clearwater,

Florida, USA, 2010.

K. K. Win, W. Nowak, H. Matsuda, M. Hasatani, Z. Bis, J. Krzywanski,

W. Gajewski, Transport velocity of coarse particles in multi-solid

fluidized bed, Journal of Chemical Engineering of Japan 28 (5) (1995)


J. Kotowicz, A. Balicki, Analysis of the thermodynamic and economic

efficiency of supercritical power unit with cfb boiler fed with lignite and

air separation unit based on high-temperature membrane technology,

Journal of Power Technologies 93 (5) (2013) 308–313.

D. Pallares, F. Johnsson, Macroscopic modelling of fluid dynamics in

large-scale circulating fluidized beds, Progress in energy and combustion

science 32 (5) (2006) 539–569.

S. Kalogirou, Applications of artificial neural networks in energy systems,

Energy Conversion and Management 40 (10) (1999) 1073–

C. Zhao, L. Dun, W. Zhou, X. Chen, D. Zeng, T. Flynn, D. Kraft, Coal

combustion characteristics on an oxy-cfb combustor with warm flue

gas recycle, in: Proceedings of the 21st International Conference on

Fluidized Bed Combustion, 2012, pp. 3–6.

R. R. Jensen, S. Karki, H. Salehfar, Artificial neural network-based

estimation of mercury speciation in combustion flue gases, Fuel Processing

Technology 85 (6) (2004) 451–462.

U. Kesgin, Genetic algorithm and artificial neural network for engine

optimisation of efficiency and nox emission, Fuel 83 (7) (2004) 885–

F. Christo, A. Masri, E. Nebot, T. Turanyi, Utilising artificial neural network

and repro-modelling in turbulent combustion, in: Neural Networks,

Proceedings., IEEE International Conference on, Vol. 2,

IEEE, 1995, pp. 911–916.

S. Milanic, R. Karba, Neural network models for predictive control of a

thermal plant, in: Proc. of the Int. Conf. EANN ’96, London, UK, 1996,

pp. 151–154.

B. Muller, H. Keller, Neural networks for combustion process modeling.,

in: Proc. of the Int. Conf. EANN ’96, London, UK, 1996, pp. 87–

M. W. Gardner, S. Dorling, Artificial neural networks (the multilayer

perceptron)—a review of applications in the atmospheric sciences, Atmospheric

environment 32 (14) (1998) 2627–2636.

S. Arumugam, G. Sriram, P. S. Subramanian, Application of artificial

intelligence to predict the performance and exhaust emissions of

diesel engine using rapeseed oil methyl ester, Procedia Engineering

(2012) 853–860.

P. Boniecki, J. Dach, K. Pilarski, H. Piekarska-Boniecka, Artificial neural

networks for modeling ammonia emissions released from sewage

sludge composting, Atmospheric Environment 57 (2012) 49–54.

C. Carnevale, G. Finzi, E. Pisoni, M. Volta, Neuro-fuzzy and neural network

systems for air quality control, Atmospheric Environment 43 (31) (2009) 4811–4821.

A. de Lucas, A. Durán, M. Carmona, M. Lapuerta, Modeling diesel

particulate emissions with neural networks, Fuel 80 (4) (2001) 539–

Z. Hao, C. Kefa, M. Jianbo, Combining neural network and genetic algorithms

to optimize low no x pulverized coal combustion, Fuel 80 (15)

(2001) 2163–2169.

R. Karada˘ g, Ö. Akgöbek, The prediction of convective heat transfer in

floor-heating systems by artificial neural networks, International Communications

in Heat and Mass Transfer 35 (3) (2008) 312–325.

T. Kwater, Z. Kedzior, B. Twarog, Estimation by artificial neural network

in ecological problems., in: Proc. AMSE-Conference MS’2001, Lviv,

Ukraine, 2001, pp. 212–215.

J. Krzywanski, W. Muskała, W. Nowak, Application of neural networks

for determining of the convective heat transfer coefficient in a circulating

fluidized bed, Power Engineering 11 (2008) 761–764.

J. Krzywanski, W. Nowak, Modeling of heat transfer coefficient in the

furnace of cfb boilers by artificial neural network approach, International

Journal of Heat and Mass Transfer 55 (15) (2012) 4246–4253.

Y. Miyamoto, Y. Kurosaki, H. Fujiyama, E. Nanbu, Dynamic characteristic

analysis and combustion control for a fluidized bed incinerator,

Control Engineering Practice 6 (9) (1998) 1159–1168.

E. Molga, Neural network approach to support modelling of chemical

reactors: problems, resolutions, criteria of application, Chemical Engineering

and Processing: Process Intensification 42 (8) (2003) 675–

S. S. Nagendra, M. Khare, Artificial neural network approach for modelling

nitrogen dioxide dispersion from vehicular exhaust emissions,

Ecological Modelling 190 (1) (2006) 99–115.

L. E. Olcese, B. M. Toselli, A method to estimate emission rates

from industrial stacks based on neural networks, Chemosphere 57 (7)

(2004) 691–696.

S. L. Reich, D. Gomez, L. Dawidowski, Artificial neural network for the

identification of unknown air pollution sources, Atmospheric Environment

(18) (1999) 3045–3052.

S. S. Sablani, A neural network approach for non-iterative calculation

of heat transfer coefficient in fluid–particle systems, Chemical Engineering

and Processing: Process Intensification 40 (4) (2001) 363–

Ü. A. S¸ ahin, C. Bayat, O. N. Uçan, Application of cellular neural network

(cnn) to the prediction of missing air pollutant data, Atmospheric

Research 101 (1) (2011) 314–326.

S. Tasdemir, I. Saritas, M. Ciniviz, N. Allahverdi, Artificial neural network

and fuzzy expert system comparison for prediction of performance

and emission parameters on a gasoline engine, Expert Systems

with Applications 38 (11) (2011) 13912–13923.

A. Tuma, H.-D. Haasis, O. Rentz, Development of emission orientated

production control strategies using fuzzy expert systems, neural networks

and neuro-fuzzy approaches, Fuzzy sets and systems 77 (3)

(1996) 255–264.

Q. Wang, G. Xie, M. Zeng, L. Luo, Prediction of heat transfer rates for

shell-and-tube heat exchangers by artificial neural networks approach,

Journal of Thermal Science 15 (3) (2006) 257–262.

M. Xiaomin, Recognition of toxic gases emission in power plant based

on artificial neural network, Energy Procedia 17 (2012) 1578–1584.

J. Zhang, F. Haghighat, Development of artificial neural network based

heat convection algorithm for thermal simulation of large rectangular

cross-sectional area earth-to-air heat exchangers, Energy and Buildings

(4) (2010) 435–440.

Y. Zhang, Y. Ding, Z. Wu, L. Kong, T. Chou, Modeling and coordinative

optimization of no x emission and efficiency of utility boilers with neural

network, Korean Journal of Chemical Engineering 24 (6) (2007) 1118–

H. Zhou, K. Cen, J. Fan, Modeling and optimization of the nox emission

characteristics of a tangentially fired boiler with artificial neural

networks, Energy 29 (1) (2004) 167–183.

B. P. Grandjean, et al., Special issue on application of neural networks

to multiphase reactors (2003).

C. Faur-Brasquet, P. Le Cloirec, Modelling of the flow behavior of activated

carbon cloths using a neural network approach, Chemical Engineering

and Processing: Process Intensification 42 (8) (2003) 645–

H. Lin, W. Chen, A. Tsutsumi, Long-term prediction of nonlinear hydrodynamics

in bubble columns by using artificial neural networks, Chemical

Engineering and Processing: Process Intensification 42 (8) (2003)


A. Shaikh, M. Al-Dahhan, Development of an artificial neural network

correlation for prediction of overall gas holdup in bubble column reactors,

Chemical Engineering and Processing: Process Intensification

(8) (2003) 599–610.

G. Bollas, S. Papadokonstadakis, J. Michalopoulos, G. Arampatzis,

A. Lappas, I. Vasalos, A. Lygeros, Using hybrid neural networks in

scaling up an fcc model from a pilot plant to an industrial unit, Chemical

Engineering and Processing: Process Intensification 42 (8) (2003)


T. Abbas, M. Awais, F. Lockwood, An artificial intelligence treatment

of devolatilization for pulverized coal and biomass in co-fired flames,

Combustion and flame 132 (3) (2003) 305–318.

J. Kukkonen, L. Partanen, A. Karppinen, J. Ruuskanen, H. Junninen,

M. Kolehmainen, H. Niska, S. Dorling, T. Chatterton, R. Foxall, et al.,

Extensive evaluation of neural network models for the prediction of NO

and PM 10 concentrations, compared with a deterministic modelling

system and measurements in central Helsinki, Atmospheric Environment

(32) (2003) 4539–4550.

H. Ye, R. Nicolai, L. Reh, A bayesian–gaussian neural network and its

applications in process engineering, Chemical Engineering and Processing:

Process Intensification 37 (5) (1998) 439–449.

W. Muskała, J. Krzywa´ nski, T. Czakiert, W. Nowak, The research of

CFB boiler operation for oxygen-enhanced dried lignite combustion,

Rynek Energii 1 (92) (2011) 172–176.

J. Krzywa´ nski, R. Rajczyk, W. Nowak, Model research of gas emissions

from lignite and biomass co-combustion in a large scale cfb

boiler, Chemical and Process Engineering 35 (2) (2014) 217–231.


  • There are currently no refbacks.