Research/Technical Note | | Peer-Reviewed

Design of Multi-Input Multi-Output Non-linear Model Predictive Control for Main Steam Temperature of Super Critical Boiler

Received: 6 January 2024     Accepted: 1 February 2024     Published: 21 February 2024
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Abstract

Flexible operation of coal-fired power plants is becoming increasingly necessary for successful integration of large-scale renewable power generation into the power grid. The maximum ramp rate and the number of load cycles are generally limited by the thermal stress experienced by the boiler pressure parts, turbine metallurgy and creep and fatigue of critical thick-walled components Main steam temperature is a critical operating parameter that must be controlled within acceptable limits for safe operation. Main steam temperature deviation beyond acceptable limit has impact on boiler pressure parts and turbine material of construction due to creep and fatigue effect. Base load operating units do not require steep ramp rate and hence recommended ramping rates are kept low within the safe operating zone in comparison to the flexible operation of the units with wide range load change width. Thermal stresses are caused by the temperature changes inside the thick-walled components and turbine steam admission parameters. Hence, the quality of main steam temperature control plays a vital role in flexible operation of the coal fired units. Conventional cascaded PID temperature control loop architecture performs well at steady state condition within a limited variation of load change at low ramp rate but it acts slowly and performs poorly at transient operating conditions of flexible operation of the boiler turbine with wide range load variation and load cycle with high ramp rate and remains far from rated conditions. In this paper, a Multi-Input Multi-Output (MIMO) Non-linear Model Predictive Control (MPC) design for regulation of the main steam temperature of a Once-Through supercritical Boiler is proposed. The controller is based on a non-linear dynamic model which incorporates dynamics of the variables of interest. It has the capability to operate effectively across a wide load range while maintaining main steam temperature within acceptable limits. A notable advancement in this design of MPC is the incorporation of coal flow demand and feedwater flow demand as additional control inputs alongside primary and secondary spray flows. In simulation test cases, the MPC controller demonstrates satisfactory performance and computational efficiency.

Published in International Journal of Mechanical Engineering and Applications (Volume 12, Issue 1)
DOI 10.11648/j.ijmea.20241201.13
Page(s) 18-31
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Dynamic Optimization, Main Steam Temperature Control, Model Predictive Controller, Once Through Boiler Turbine System, Parameter Estimation

References
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[2] Y. Iino, M. Y., K. Takahashi, S. H. & K. Nagata. A new PID controller tuning system and its application to a flue gas temperature control in a gas turbine power plant. IEEE International Conference on Control Applications 2, (1998).
[3] Chrif, L. & Meguenni, K. Aircraft Control System Using Model Predictive Controller. TELKOMNIKA Indonesian Journal of Electrical Engineering 15, 259 (2015).
[4] Moon, U.-C., Lee, Y. & Lee, K. Y. Practical dynamic matrix control for thermal power plant coordinated control. Control Engineering Practice 71, 154–163 (2018).
[5] Moon, U.-C. & Kim, W.-H. Temperature Control of Ultrasupercritical Once-through Boiler-turbine System Using Multi-input Multi-output Dynamic Matrix Control. Journal of Electrical Engineering and Technology 6, (2011).
[6] Clarke, D. W., Mohtadi, C. & Tuffs, P. S. Generalized predictive control—Part I. The basic algorithm. Automatica 23, 137–148 (1987).
[7] Ławryńczuk, M. Nonlinear predictive control of a boiler-turbine unit: A state-space approach with successive on-line model linearisation and quadratic optimisation. ISA Trans 67, 476–495 (2017).
[8] Qin, S. J. & Badgwell, T. A. An Overview of Nonlinear Model Predictive Control Applications. in Nonlinear Model Predictive Control (eds. Allgöwer, F. & Zheng, A.) 369–392 (Birkhäuser Basel, 2000). https://doi.org/10.1007/978-3-0348-8407-5_21
[9] Liu, X. & Cui, J. Fuzzy economic model predictive control for thermal power plant. IET Control Theory & Applications 13, 1113–1120 (2019).
[10] Wang, L., Cai, Y. & Ding, B. Robust Model Predictive Control With Bi-Level Optimization for Boiler-Turbine System. IEEE Access 9, 48244–48253 (2021).
[11] García, C. E., Prett, D. M. & Morari, M. Model predictive control: Theory and practice—A survey. Automatica 25, 335–348 (1989).
[12] He, F., Wang, P., Su, Z. & Lee, K. A dynamic model for once-through boiler-turbine units with superheated steam temperature. Applied Thermal Engineering 170, 114912 (2020).
[13] Rackauckas, C. and N. & Qing. Differential Equations-a performant and feature-rich ecosystem for solving differential equations in Julia. Journal of Open Research Software 5, (2017).
[14] Shashi Gowda, Y. M., Chris Laughman, R. A. & Chris Rackauckas, V. S. Modelling Toolkit: A Composable Graph Transformation System For Equation-Based Modelling. (2021).
[15] Christ, S., Schwabeneder, D., Rackauckas, C., Borregaard, M. K. & Breloff, T. Plots.jl -- a user extendable plotting API for the julia programming language. arXiv.org https://arxiv.org/abs/2204.08775v3 (2022).
[16] Dale E. Seborg, Thomas F. Edgar, Duncan A. Mellichamp & Francis J. Doyle III. Process Dynamics and Control. (Wiley, 2011).
Cite This Article
  • APA Style

    Basu, S., Cherian, S., Johnson, J. (2024). Design of Multi-Input Multi-Output Non-linear Model Predictive Control for Main Steam Temperature of Super Critical Boiler. International Journal of Mechanical Engineering and Applications, 12(1), 18-31. https://doi.org/10.11648/j.ijmea.20241201.13

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    ACS Style

    Basu, S.; Cherian, S.; Johnson, J. Design of Multi-Input Multi-Output Non-linear Model Predictive Control for Main Steam Temperature of Super Critical Boiler. Int. J. Mech. Eng. Appl. 2024, 12(1), 18-31. doi: 10.11648/j.ijmea.20241201.13

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    AMA Style

    Basu S, Cherian S, Johnson J. Design of Multi-Input Multi-Output Non-linear Model Predictive Control for Main Steam Temperature of Super Critical Boiler. Int J Mech Eng Appl. 2024;12(1):18-31. doi: 10.11648/j.ijmea.20241201.13

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  • @article{10.11648/j.ijmea.20241201.13,
      author = {Sumanta Basu and Sushil Cherian and Jisna Johnson},
      title = {Design of Multi-Input Multi-Output Non-linear Model Predictive Control for Main Steam Temperature of Super Critical Boiler},
      journal = {International Journal of Mechanical Engineering and Applications},
      volume = {12},
      number = {1},
      pages = {18-31},
      doi = {10.11648/j.ijmea.20241201.13},
      url = {https://doi.org/10.11648/j.ijmea.20241201.13},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmea.20241201.13},
      abstract = {Flexible operation of coal-fired power plants is becoming increasingly necessary for successful integration of large-scale renewable power generation into the power grid. The maximum ramp rate and the number of load cycles are generally limited by the thermal stress experienced by the boiler pressure parts, turbine metallurgy and creep and fatigue of critical thick-walled components Main steam temperature is a critical operating parameter that must be controlled within acceptable limits for safe operation. Main steam temperature deviation beyond acceptable limit has impact on boiler pressure parts and turbine material of construction due to creep and fatigue effect. Base load operating units do not require steep ramp rate and hence recommended ramping rates are kept low within the safe operating zone in comparison to the flexible operation of the units with wide range load change width. Thermal stresses are caused by the temperature changes inside the thick-walled components and turbine steam admission parameters. Hence, the quality of main steam temperature control plays a vital role in flexible operation of the coal fired units. Conventional cascaded PID temperature control loop architecture performs well at steady state condition within a limited variation of load change at low ramp rate but it acts slowly and performs poorly at transient operating conditions of flexible operation of the boiler turbine with wide range load variation and load cycle with high ramp rate and remains far from rated conditions. In this paper, a Multi-Input Multi-Output (MIMO) Non-linear Model Predictive Control (MPC) design for regulation of the main steam temperature of a Once-Through supercritical Boiler is proposed. The controller is based on a non-linear dynamic model which incorporates dynamics of the variables of interest. It has the capability to operate effectively across a wide load range while maintaining main steam temperature within acceptable limits. A notable advancement in this design of MPC is the incorporation of coal flow demand and feedwater flow demand as additional control inputs alongside primary and secondary spray flows. In simulation test cases, the MPC controller demonstrates satisfactory performance and computational efficiency.
    },
     year = {2024}
    }
    

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  • TY  - JOUR
    T1  - Design of Multi-Input Multi-Output Non-linear Model Predictive Control for Main Steam Temperature of Super Critical Boiler
    AU  - Sumanta Basu
    AU  - Sushil Cherian
    AU  - Jisna Johnson
    Y1  - 2024/02/21
    PY  - 2024
    N1  - https://doi.org/10.11648/j.ijmea.20241201.13
    DO  - 10.11648/j.ijmea.20241201.13
    T2  - International Journal of Mechanical Engineering and Applications
    JF  - International Journal of Mechanical Engineering and Applications
    JO  - International Journal of Mechanical Engineering and Applications
    SP  - 18
    EP  - 31
    PB  - Science Publishing Group
    SN  - 2330-0248
    UR  - https://doi.org/10.11648/j.ijmea.20241201.13
    AB  - Flexible operation of coal-fired power plants is becoming increasingly necessary for successful integration of large-scale renewable power generation into the power grid. The maximum ramp rate and the number of load cycles are generally limited by the thermal stress experienced by the boiler pressure parts, turbine metallurgy and creep and fatigue of critical thick-walled components Main steam temperature is a critical operating parameter that must be controlled within acceptable limits for safe operation. Main steam temperature deviation beyond acceptable limit has impact on boiler pressure parts and turbine material of construction due to creep and fatigue effect. Base load operating units do not require steep ramp rate and hence recommended ramping rates are kept low within the safe operating zone in comparison to the flexible operation of the units with wide range load change width. Thermal stresses are caused by the temperature changes inside the thick-walled components and turbine steam admission parameters. Hence, the quality of main steam temperature control plays a vital role in flexible operation of the coal fired units. Conventional cascaded PID temperature control loop architecture performs well at steady state condition within a limited variation of load change at low ramp rate but it acts slowly and performs poorly at transient operating conditions of flexible operation of the boiler turbine with wide range load variation and load cycle with high ramp rate and remains far from rated conditions. In this paper, a Multi-Input Multi-Output (MIMO) Non-linear Model Predictive Control (MPC) design for regulation of the main steam temperature of a Once-Through supercritical Boiler is proposed. The controller is based on a non-linear dynamic model which incorporates dynamics of the variables of interest. It has the capability to operate effectively across a wide load range while maintaining main steam temperature within acceptable limits. A notable advancement in this design of MPC is the incorporation of coal flow demand and feedwater flow demand as additional control inputs alongside primary and secondary spray flows. In simulation test cases, the MPC controller demonstrates satisfactory performance and computational efficiency.
    
    VL  - 12
    IS  - 1
    ER  - 

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Author Information
  • L&T MHI Power Boilers Private Limited, Faridabad, India

  • Kalki Communication Technologies Pvt Ltd, Ernakulam, India

  • Kalki Communication Technologies Pvt Ltd, Ernakulam, India

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