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Design and implementation of extended predictive functional control for boiler-turbine unit of power plant
, Article 24th Mediterranean Conference on Control and Automation, 21 June 2016 through 24 June 2016 ; 2016 , Pages 131-134 ; 9781467383455 (ISBN) ; Haeri, M ; MCA ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
In this paper, a new model predictive controller is introduced to control a power unit process with three inputs and three outputs. This method is proposed to reduce the complexity of the required computation. In fact, the presented controller ensures achieving an acceptable performance in the presence of noise and disturbances and reduces the volume of calculations to control a complex and nonlinear boilerturbine process. The simulation results indicate that the implementation of the proposed controller requires less computing time while the performance degradation is not more than five percent
Suppression of harmonic perturbations and bifurcation control in tracking objectives of a boiler-turbine unit in power grid
, Article Nonlinear Dynamics ; Vol. 76, Issue. 3 , 2014 , pp. 1693-1709 ; ISSN: 0924090X ; Vossoughi, G ; Alasty, A ; Sharif University of Technology
Abstract
In the presence of harmonic disturbances, boiler-turbine units may demonstrate quasi-periodic behaviour due to the occurrence of various types of bifurcation. In this article, a nonlinear model of boiler-turbine unit is considered in which drum pressure, electric output and drum water level are controlled via manipulation of valve positions for fuel, steam and feed-water flow rates. For bifurcation control in tracking problem, two controllers are designed based on gain scheduling and feedback linearization (FBL). To investigate the efficiency of control strategies, three cases are considered for desired tracking objectives (a sequence of steps, ramps/steps, and a combination of them)....
Multivariable robust adaptive sliding mode control of an industrial boiler-turbine in the presence of modeling imprecisions and external disturbances: A comparison with type-I servo controller
, Article ISA Transactions ; Volume 58 , September , 2015 , Pages 398-408 ; 00190578 (ISSN) ; Moradi, H ; Vossoughi, G ; Sharif University of Technology
ISA - Instrumentation, Systems, and Automation Society
2015
Abstract
To guarantee the safety and efficient performance of the power plant, a robust controller for the boiler-turbine unit is needed. In this paper, a robust adaptive sliding mode controller (RASMC) is proposed to control a nonlinear multi-input multi-output (MIMO) model of industrial boiler-turbine unit, in the presence of unknown bounded uncertainties and external disturbances. To overcome the coupled nonlinearities and investigate the zero dynamics, input-output linearization is performed, and then the new decoupled inputs are derived. To tackle the uncertainties and external disturbances, appropriate adaption laws are introduced. For constructing the RASMC, suitable sliding surface is...
Comparison of fuzzy logic and neural network in life prediction of boiler tubes
, Article International Journal of Fatigue ; Volume 29, Issue 3 , 2007 , Pages 489-498 ; 01421123 (ISSN) ; Saidi, M. H ; Sharif University of Technology
2007
Abstract
The life prediction of equipments guarantees reliable, safe, efficient and continuous operation of thermal power plants. In this paper wall thickness of reheater tubes of boiler number 3 of Neka power plant in north of Iran are measured at several points during maintenance shut down periods. Thickness dependency vs. time has been investigated. Artificial Neural Network (ANN) as a tool has been acquired to determine this dependency. Extrapolation of thickness function vs. time applying maximum normal stress criteria results in corresponding thickness. The maximum wall reduction rates have been calculated by two schemes namely Fuzzy function (FF) and Neural Network (ANN) applying numerical...
Suppression of harmonic perturbations and bifurcation control in tracking objectives of a boiler-turbine unit in power grid
, Article Nonlinear Dynamics ; Volume 76, Issue 3 , May 2014 , Pages 1693-1709 ; Vossoughi, G ; Alasty, A ; Sharif University of Technology
Abstract
In the presence of harmonic disturbances, boiler-turbine units may demonstrate quasi-periodic behaviour due to the occurrence of various types of bifurcation. In this article, a nonlinear model of boiler-turbine unit is considered in which drum pressure, electric output and drum water level are controlled via manipulation of valve positions for fuel, steam and feed-water flow rates. For bifurcation control in tracking problem, two controllers are designed based on gain scheduling and feedback linearization (FBL). To investigate the efficiency of control strategies, three cases are considered for desired tracking objectives (a sequence of steps, ramps/steps, and a combination of them)....
Using sliding mode control to adjust drum level of a boiler unit with time varying parameters
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 5 , 2010 , Pages 29-33 ; 9780791849194 (ISBN) ; Bakhtiari Nejad, F ; Saffar Avval, M ; Alasty, A
2010
Abstract
Stable control of water level of drum is of great importance for economic operation of power plant steam generator systems. In this paper, a linear model of the boiler unit with time varying parameters is used for simulation. Two transfer functions between drum water level (output variable) and feed-water and steam mass rates (input variables) are considered. Variation of model parameters may be arisen from disturbances affecting water level of drum, model uncertainties and parameter mismatch due to the variant operating conditions. To achieve a perfect tracking of the desired drum water level, two sliding mode controllers are designed separately. Results show that the designed controllers...
Design & application of adaptive variable structure & H∞ robust optimal schemes in nonlinear control of boiler-turbine unit in the presence of various uncertainties
, Article Energy ; Volume 142 , 2018 , Pages 1040-1056 ; 03605442 (ISSN) ; Moradi, H ; Vossoughi, G ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this article, to improve the precision, performance and robustness of an industrial boiler-turbine, two robust controllers are designed. First, a robust adaptive variable structure control scheme (RAVSC) is proposed to control a nonlinear multi-inputs multi-outputs (MIMO) model of an industrial boiler-turbine unit, in the presence of significant uncertainties and external disturbances. To guarantee the reliable performance of the RAVSC, appropriate adaption and control laws are introduced to compensate the uncertainties and modeling imprecisions and guarantee the convergence to the sliding surface. Then, the robustness and stability of the proposed RAVSC is proved via Lyapunov stability...
Design and Manufacture of Steam Jet Propulsion System
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeed (Supervisor)
Abstract
Nowadays, there is a focus on developing a propulsion system with higher efficiency and performance in comparison to conventional systems. Many diverse systems have been designed for the vessel propulsion and everyday, utilizing new ideas, their performance and energy consumption are being improved. Direct use of steam energy is a noble and new idea. In this research, the steam jet propulsion system has been explained and current worldwide research on the topic has been investigated. Considering the shortage of primary data in the field and the novelty of subject, required information for the manufacturing of a sample model of this special propulsion system has been gathered and a design for...
Nonlinear dynamics and control of bifurcation to regulate the performance of a boiler-turbine unit
, Article Energy Conversion and Management ; Volume 68 , 2013 , Pages 105-113 ; 01968904 (ISSN) ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
2013
Abstract
The economical operations of power plants and environmental awareness are the major factors affecting the importance of control in boiler-turbine units. In this paper, a multivariable nonlinear model of boiler-turbine unit is considered. Drum pressure, electric output and water level of drum (as output variables) are adjusted at desired values by manipulation of valve positions for fuel, steam and feed-water flow rates (as input variables). Nonlinear dynamics of the unit is investigated through the concepts of bifurcation and limit cycles behaviour. In the presence of harmonic disturbances, some coefficients of the dynamic model, fuel and steam flow rates play as the bifurcation parameters....
Thermodynamic analysis of different configurations for microturbine cycles in simple and cogeneration systems
, Article 2006 ASME 51st Turbo Expo, Barcelona, 6 May 2006 through 11 May 2006 ; Volume 5 PART A , 2006 , Pages 247-255 ; 0791842401 (ISBN); 9780791842409 (ISBN) ; Khaledi, H ; Ghofrani, M. B ; The International Gas Turbine Institute ; Sharif University of Technology
2006
Abstract
In recent years, the development of distributed power generation has resulted in significant reduction in network losses and transmission costs while it has increased reliability. Microturbine is one of these power generators that has the ability of relatively high power generation in spite of its small volume [1], [2]. In this paper, different layouts for advanced microturbine cycles are analyzed. In order to modify cycle characteristics such as power and efficiency, and reduce exergy destruction, different configurations including intercooler, aftercooler, and heat recovery boiler are separately and synthetically analyzed and compared. The effects of various parameters, such as compressor...
Using sliding mode control to adjust drum level of a boiler unit with time varying parameters
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis ; Vol. 5 , 2010 , pp. 29-33 ; ISBN: 9780791849194 ; Bakhtiari-Nejad, F ; Saffar-Avval, M ; Alasty, A ; Sharif University of Technology
Abstract
Stable control of water level of drum is of great importance for economic operation of power plant steam generator systems. In this paper, a linear model of the boiler unit with time varying parameters is used for simulation. Two transfer functions between drum water level (output variable) and feed-water and steam mass rates (input variables) are considered. Variation of model parameters may be arisen from disturbances affecting water level of drum, model uncertainties and parameter mismatch due to the variant operating conditions. To achieve a perfect tracking of the desired drum water level, two sliding mode controllers are designed separately. Results show that the designed controllers...
Numerical study on NOx reduction in a large-scale heavy fuel oil-fired boiler using suitable burner adjustments
, Article Energy ; Volume 199 , 2020 ; Fatin, A ; Bordbar, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
A numerical framework was carefully developed to simulate the combustion of heavy-fuel-oil (HFO) in a large-scale boiler. The present numerical solutions were compared with the measured data of a laboratory benchmark test and on-site operational data of the chosen HFO-fired boiler. Next, the developed framework was used to perform sensitivity analyses aiming to reduce the NO emission from the HFO-fired boiler without any adverse effect on its combustion performance. Practically, this study focused on re-adjustments of 24 working burners, which could control combustion in the HFO-fired boiler. The early outcome showed that the boiler NO emission and its combustion performance could be...
Multivariable robust regulation of an industrial boiler-turbine with model uncertainties
, Article 9th International Conference on Modern Circuits and Systems Technologies, MOCAST 2020, 7 September 2020 through 9 September 2020 ; 2020 ; Moradi, H ; Vossoughi, G ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Efficient robust control methods are required to keep the boiler-turbine unit performance appropriately. In this paper, a hybrid multivariable robust control strategy including the regulator and observer is designed to improve the performance of an industrial boiler-turbine unit. In the nonlinear model of the process, output variables including the drum pressure, electric power and water level of the drum are controlled at the desired set-points by manipulation of the fuel, steam, and feed-water flow rates. Due to economic and technical reasons and for the estimation of process states, the full-order observer is designed. For disturbance rejection and process stability, a regulator system is...
Nonlinear dynamics and control of bifurcation to regulate the performance of a boiler-turbine unit
, Article Energy Conversion and Management ; Vol. 68 , 2013 , pp. 105-113 ; ISSN: 01968904 ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
Abstract
The economical operations of power plants and environmental awareness are the major factors affecting the importance of control in boiler-turbine units. In this paper, a multivariable nonlinear model of boiler-turbine unit is considered. Drum pressure, electric output and water level of drum (as output variables) are adjusted at desired values by manipulation of valve positions for fuel, steam and feed-water flow rates (as input variables). Nonlinear dynamics of the unit is investigated through the concepts of bifurcation and limit cycles behaviour. In the presence of harmonic disturbances, some coefficients of the dynamic model, fuel and steam flow rates play as the bifurcation parameters....
Multivariable control of an industrial boiler-turbine unit with nonlinear model: A comparison between gain scheduling and feedback linearization approaches
, Article Scientia Iranica ; Volume 20, Issue 5 , 2013 , Pages 1485-1498 ; 10263098 (ISSN) ; Alasty, A ; Saffar Avval, M ; Bakhtiari Nejad, F ; Sharif University of Technology
Sharif University of Technology
2013
Abstract
Due to demands for the economical operations of power plants and environmental awareness, performance control of a boiler-turbine unit is of great importance. In this paper, a nonlinear Multi Input-Multi Output model (MIMO) of a utility boilerturbine unit is considered. Drum pressure, generator electric output and drum water level (as the output variables) are controlled by manipulation of valves position for fuel, feedwater and steam flows. After state space representation of the problem, two controllers, based on gain scheduling and feedback linearization, are designed. Tracking performance of the system is investigated and discussed for three cases of 'near', 'far' and 'so far' setpoints....
Extension of weighted sum of gray gas data to mathematical simulation of radiative heat transfer in a boiler with gas-soot media
, Article The Scientific World Journal ; Vol. 2014 , 2014 ; ISSN: 1537744X ; Nouri-Borujerdi, A ; Kazi, S. N ; Yarmand, H ; Sharif University of Technology
Abstract
In this study an expression for soot absorption coefficient is introduced to extend the weighted-sum-of-gray gases data to the furnace medium containing gas-soot mixture in a utility boiler 150 MWe. Heat transfer and temperature distribution of walls and within the furnace space are predicted by zone method technique. Analyses have been done considering both cases of presence and absence of soot particles at 100% load. To validate the proposed soot absorption coefficient, the expression is coupled with the Taylor and Foster's data as well as Truelove's data for CO2-H2O mixture and the total emissivities are calculated and compared with the Truelove's parameters for 3-term and 4-term gray...
Numerical simulation of NOx pollutant formation in a natural gas fired power generation boiler, by using burner's parameters
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 6, Issue PARTS A AND B , 2012 , Pages 1159-1163 ; 9780791845226 (ISBN) ; Afshin, H ; Sharif University of Technology
2012
Abstract
The major source of energy is fossil fuels, known as hydrocarbon containing C and H as the main elements. The heat generated from combustion of these fuels is used in power generation cycles to generate electricity. Main products of a hydrocarbon combustion reaction are water and carbon dioxide, but due to some reasons such as excessive temperature and inappropriate air-fuel mixing, always some pollutants are formed. One of the major concerns of recent years are NOx pollutants, which is mostly generated in the high temperature combustions. According to the geographical and economic issues, most countries are using coal as fuel and many researches have been conducted about pollutant formation...
Improving the performance of a nonlinear boiler–turbine unit via bifurcation control of external disturbances: a comparison between sliding mode and feedback linearization control approaches
, Article Nonlinear Dynamics ; Volume 85, Issue 1 , 2016 , Pages 229-243 ; 0924090X (ISSN) ; Abbasi, M. H ; Moradian, H ; Sharif University of Technology
Springer Netherlands
Abstract
Boiler–turbine units may show quasiperiodic behavior due to the bifurcation occurrence in the presence of harmonic disturbances. In this study, a multi-input–multi-output nonlinear dynamic model of a boiler–turbine unit is considered. Drum pressure, electric output, and fluid density are the state variables and adjusted at the desired values by manipulation of the input variables. Control inputs are the valve positions for fuel, steam and feed-water flow rates. To improve the quasiperiodic behavior of the system and bifurcation control in tracking problem, two controllers are designed: feedback linearization control and nonlinear sliding mode control (SMC). The feedback linearization...
Multivariable optimal control of an industrial nonlinear boiler–turbine unit
, Article Meccanica ; Volume 51, Issue 4 , 2016 , Pages 859-875 ; 00256455 (ISSN) ; Vossoughi, G ; Sharif University of Technology
Abstract
Performance control of a boiler–turbine unit is of great importance due to demands for the economical operations of power plants and environmental awareness. In this paper, an optimal control strategy is designed to achieve the desired performance of a boiler–turbine unit. A multivariable nonlinear model of a utility boiler–turbine unit is considered. By manipulation of valves position for the fuel, steam and feed-water flows; output variables including the drum pressure, electric output and fluid density (and consequently drum water level) are controlled. Performance measure of the problem is defined such that the control efforts are minimized while the tracking objectives are obtained. In...
Control of a nonlinear boiler- turbine unit using two methods: Gain scheduling & feedback linearization
, Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 9 PART A , 2008 , Pages 491-499 ; 0791843033 (ISBN); 9780791843031 (ISBN) ; Alasty, A ; Bakhtiari Nejad, F ; Sharif University of Technology
2008
Abstract
To achieve a good performance of a boiler-turbine unit, dynamic variables such as steam pressure, water level of drum and electric output of turbine must be controlled. In this paper a nonlinear model of the boiler-turbine unit is considered in which the inputs are the valve positions of fuel flow, steam control, and feed-water flow. Using two control methods, feedback linearization and gain scheduling, a PI controller is designed. It is shown that by applying both methods, system goes from one operating point to another with an appropriate specification of time response. Results show that system with a controller designed based on gain scheduling method has a better time response from a...