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Research Papers: Energy Systems Analysis

# Modeling Time Variations of Boiler Efficiency

[+] Author and Article Information
Ahmed Rehan

Systems Engineering Department,
King Fahd University of Petroleum & Minerals,
Dhahran 31261, Saudi Arabia
e-mail: rehan_eme@yahoo.com

Mohamed A. Habib

Department of Mechanical Engineering,
KACST TIC on CCS,
King Fahd University of Petroleum & Minerals,
Dhahran 31261, Saudi Arabia
e-mail: mahabib@kfupm.edu.sa

Moustafa Elshafei

Department of Systems Engineering,
King Fahd University of Petroleum and Minerals,
KFUPM Box 405,
Dhahran 31261, Saudi Arabia
e-mail: elshafei@kfupm.edu.sa

Dhahran Technovalley,
King Fahd University of Petroleum and Minerals,
Dhahran 31261, Saudi Arabia

1Corresponding author.

Contributed by the Advanced Energy Systems Division of ASME for publication in the JOURNAL OF ENERGY RESOURCES TECHNOLOGY. Manuscript received June 7, 2016; final manuscript received September 23, 2017; published online November 9, 2017. Assoc. Editor: Reza Sheikhi.

J. Energy Resour. Technol 140(5), 052001 (Nov 09, 2017) (15 pages) Paper No: JERT-16-1240; doi: 10.1115/1.4038236 History: Received June 07, 2016; Revised September 23, 2017

## Abstract

Boiler's efficiency is one of the important performance indicators of boiler. To keep track of operation cost, efficiency needs to be calculated with adequate accuracy by employing effective mathematical tools. In this work, a new modification in conventional mathematical formulation of efficiency is presented based on time-varying efficiency using time-varying operational variables of boiler. This modification was accomplished using indirect method of efficiency by applying experimental data of variables for certain time span. Moreover a second-order dynamic model of flue gas temperature (FGT) has been derived to construct the mathematical formulation of efficiency only in terms of available inputs. The resulting input–output-based model proved to be in quite agreement with efficiency calculated from experimental data. After modeling, influence of variations in air to fuel ratio (AFR) and fuel flow rate (FFR) upon efficiency has been discussed and it has been shown that time-varying efficiency covers deeper aspect of dynamic relation between efficiency and other input of boiler especially AFR and FFR. Moreover, it has been established that efficiency interacts with the dynamics of boiler, and in this respect, a dynamic relation between combustion process and boiler dynamics has been constructed via efficiency.

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## References

Shah, S. , and Adhyaru, D. M. , 2011, “ Boiler Efficiency Analysis Using Direct Method,” Nirma University International Conference on Engineering: Current Trends in Technology (NUiCONE), Gujarat, India, Dec. 8–10, pp. 1–5.
Huang, L. Y. , Wen, J. X. , Karayiannis, T. G. , and Matthews, R. D. , 1998, “ Numerical Prediction of High Efficiency Boiler Heat Exchanger Performance,” Appl. Therm. Eng., 18(11), pp. 1089–1099.
Carlon, E. , Schwarz, M. , Golicza, L. , Verma, V. K. , Prada, A. , Baratieri, M. , Haslinger, W. , and Schmidl, C. , 2015, “ Efficiency and Operational Behaviour of Small-Scale Pellet Boilers Installed in Residential Buildings,” Appl. Energy, 155, pp. 854–865.
Tanetsakunvatana, V. , and Kuprianov, V. I. , 2007, “ Experimental Study on Effects of Operating Conditions and Fuel Quality on Thermal Efficiency and Emission Performance of a 300-MW Boiler Unit Firing Thai Lignite,” Fuel Process. Technol., 88(2), pp. 199–206.
Li, Y. , and Gao, H. , 2010, “ On-Line Calculation for Thermal Efficiency of Boiler,” Asia-Pacific Power and Energy Engineering Conference (APPEEC), Chengdu, China, Mar. 28–31, pp. 1–4.
Nagar, V. , 2013, “ Boiler Efficiency Improvement Through Analysis of Losses,” Int. J. Sci. Res. Dev., 1(3), pp. 1–5.
Shi, Y. , Wang, J. , Wang, B. , and Zhang, Y. , 2011, “ On-Line Calculation Model for Thermal Efficiency of Coal-Fired Utility Boiler Based on Heating Value Identification,” International Conference on Modelling, Identification and Control (ICMIC), Shanghai, China, June 26–29, pp. 203–207.
Li, G. , Niu, P. , Liu, C. , and Zhang, W. , 2012, “ Enhanced Combination Modeling Method for Combustion Efficiency in Coal-Fired Boilers,” Appl. Soft Comput., 12(10), pp. 3132–3140.
Chayalakshmi C. L. , Jangamshetti, D. S. , and Sonoli, S. , 2015, “ Boiler Efficiency Estimation From Hydrogen Content in Fuel,” International Conference on Advances in Computing, Communications and Informatics (ICACCI), Kochi, India, Aug. 10–13, pp. 1107–1110.
Li, P. , and Zhang, C. W. , 2014, “ The Analysis Between Two Different Methods of Power Plant Boiler Thermal Efficiency,” Appl. Mech. Mater., 536–537, pp. 1578–1582.
Dedovic, N. , Igic, S. , Janic, T. , Matic-Kekic, S. , Ponjican, O. , Tomic, M. , and Savin, L. , 2012, “ Efficiency of Small Scale Manually Fed Boilers—Mathematical Models,” Energies, 5(12), pp. 1470–1489.
Barroso, J. , Barreras, F. , Amaveda, H. , and Lozano, A. , 2003, “ On the Optimization of Boiler Efficiency Using Bagasse as Fuel,” Fuel, 82(12), pp. 1451–1463.
Song, Z. , and Kusiak, A. , 2007, “ Constraint-Based Control of Boiler Efficiency: A Data-Mining Approach,” IEEE Trans. Ind. Inf., 3(1), pp. 73–83.
Žandeckis, A. , Timma, L. , Blumberga, D. , Rochas, C. , and Rošā, M. , 2013, “ Solar and Pellet Combisystem for Apartment Buildings: Heat Losses and Efficiency Improvements of the Pellet Boiler,” Appl. Energy, 101, pp. 244–252.
Zhao, H. , and Wang, P.-H. , 2009, “ Modeling and Optimization of Efficiency and NOx Emission at a Coal-Fired Utility Boiler,” Asia-Pacific Power and Energy Engineering Conference (APPEC), Wuhan, China, Mar. 27–31, pp. 1–4.
Li, S. , Xu, T. , Hui, S. , and Wei, X. , 2009, “ NOx Emission and Thermal Efficiency of a 300MWe Utility Boiler Retrofitted by Air Staging,” Appl. Energy, 86(9), pp. 1797–1803.
Weiqing, W. , 2012, “ Multi-Objective Optimization of Coal-Fired Boiler Efficiency and NOx Emission Under Different Ecological Environment,” Future Communication, Computing, Control and Management, Vol. 141, Y. Zhang , ed., Springer, Berlin, pp. 433–439.
Zhang, B. T. , Wang, C. Y. , Qin, Q. , and Li, L. , 2013, “ Influence of Boiler Combustion Adjustment on NOx Emission and Boiler Efficiency,” Adv. Mater. Res., 732–733, pp. 234–237.
Mellor, A. M. , 1980, “ Semi-Empirical Correlations for Gas Turbine Emissions, Ignition, and Flame Stabilization,” Prog. Energy Combust. Sci., 6(4), pp. 347–358.
Connors, C. S. , Barnes, J. C. , and Mellor, A. M. , 1996, “ Semiempirical Predictions and Correlations of CO Emissions From Utility Combustion Turbines,” J. Propul. Power, 12(5), pp. 926–932.
Hung, W. S. Y. , and Agan, D. D. , 1985, “ The Control of NOx and CO Emissions From 7-MW Gas Turbines With Water Injection as Influenced by Ambient Conditions,” ASME Paper No. 85-GT-50.
Lefebvre, A. H. , 1984, “ Fuel Effects on Gas Turbine Combustion-Liner Temperature, Pattern Factor, and Pollutant Emissions,” J. Aircr., 21(11), pp. 887–898.
Rizk, N. , and Mongia, H. , 1994, “ Emissions Predictions of Different Gas Turbine Combustors,” AIAA Paper No. 94-0118.
Harrington, J. A. , and Shishu, R. C. , 1973, “ A Single-Cylinder Engine Study of the Effects of Fuel Type, Fuel Stoichiometry, and Hydrogen-to-Carbon Ratio on CO, NO, and HC Exhaust Emissions,” SAE Paper No. 730476.
Bhambare, K. S. , Mitra, S. K. , and Gaitonde, U. N. , 2006, “ Modeling of a Coal-Fired Natural Circulation Boiler,” ASME J. Energy Resour. Technol., 129(2), pp. 159–167.
Ilamathi, P. , Selladurai, V. , and Balamurugan, K. , 2013, “ Modeling and Optimization of Unburned Carbon in Coal-Fired Boiler Using Artificial Neural Network and Genetic Algorithm,” ASME J. Energy Resour. Technol., 135(3), p. 032201.
Qi, L. , Huang, S. , Zhang, Y. , Xu, X. , Li, Y. , and Wang, Y. , 2014, “ A Compartmental Model for Supercritical Coal-Fired Boiler Systems,” ASME J. Energy Resour. Technol., 136(2), p. 021602.
Elshafei, M. , Habib, M. A. , Al-Zaharnah, I. , and Nemitallah, M. A. , 2014, “ Boilers Optimal Control for Maximum Load Change Rate,” ASME J. Energy Resour. Technol., 136(3), p. 031301.
Minhajullah, S. , El Ferik, S. , Elshafei, M. , and Habib, M. A. , 2012, “ MPC-Based Controller for Augmented Boiler-NOx Model,” International Multi-Conference on Systems, Signals & Devices (SSD), Chemnitz, Germany, Mar. 20–23, pp. 1–6.
Pedersen, T. S. , Hansen, T. , and Hangstrup, M. , 1996, “ Process-Optimizing Multivariable Control of a Boiler System,” UKACC International Conference on Control (Control), Exeter, UK, Sept. 2–5, pp. 787–792.
Alzaharnah, I. , Habib, M. A. , Elshafei, M. , and Ahmed, P. , 2013, “ Control of the Boiler Swing Rate for NO Emission Minimization,” Energy Fuels, 27(10), pp. 6079–6086.

## Figures

Fig. 1

Fuel composition by volume %

Fig. 2

CO variation with equivalence ratio (ϕ)

Fig. 3

Plots of available data and AFR

Fig. 4

Time variations of flue gas constituents

Fig. 5

Time variations of AFR

Fig. 6

Time variations of specific heat of flue gas Cp (kCal/kgC)

Fig. 7

Plot of hfg (kCal/kgC) of water with time

Fig. 8

Time variations of losses L1–L4

Fig. 9

Time variations of losses L5 and L6

Fig. 10

Time variations of efficiency

Fig. 11

Control implementation with dynamic efficiency

Fig. 12

Plot of FFR (SCFH) data

Fig. 13

FGT plot of model and experimental data

Fig. 14

Validation plot of FGT using data of second boiler

Fig. 15

Efficiency model with inputs and outputs

Fig. 16

Time variations of efficiency using FGT model

Fig. 17

Efficiency variations with AFR for different loads

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