Boiler-turbine control system design using continuous-time nonlinear model predictive control

A continuous-time nonlinear model predictive controller(NMPC) was designed for a boiler-turbine unit.The controller was designed by optimizing a receding-horizon performance index,with the nonlinear system approximated by its Taylor series expansion with a certain order,the magnitude saturation constraints on the inputs satisfied by increasing the predictive time,and the rate saturation conditions on the actuators satisfied by tuning the time constant of the reference trajectories in a reference governor.Simulation results showed that the controller can drive the drum pressure and output power of the nonlinear boiler-turbine unit to follow their respective reference trajectories throughout a varying operation range and keep the water level deviation within tolerances.Comparison of the NMPC scheme with the generic model control(GMC) scheme indicated that the responses are slower and there are more oscillations in the responses of the water level,fuel flow input and feed water flow input in the GMC scheme when the boiler-turbine unit is operating over a wide range.

Study on Fuzzy Self-Adaptive PID Control System of Biomass Boiler Drum Water

The paper discusses the features of the Biomass Boiler drum water level. Conventional PID Control System can not reach a satisfaction result in nonlinearity and time different from Biomass Boiler Drum Water Control System. In this study, a kind of fuzzy self-adaptive PID controller is described and this controller is used in biomass boiler’s drum water level control system. Using the simulink tool of MATLAB simulation software to simulate the fuzzy adaptive PID and conventional PID control system, the result of the comparison shows that the fuzzy self-adaptive PID has the strong anti-jamming, flexibility and adaptability as well as the higher control precision in Biomass Boiler Drum Water.

A mathematical model for optimized operation and controlin a CDQ-Boiler system

Based on analyzing the thermal process of a CDQ （coke dry quenching）-Boiler system, the mathematical model for opti-mized operation and control in the CDQ-Boiler system was developed. It includes a mathematical model for heat transferring process in the CDQ unit, a mathematical model for heat transferring process in the boiler and a combustion model for circulating gas in the CDQ-Boiler system. The model was verified by field data, then a series of simulations under several typical operating conditions of CDQ-Boiler were carried on, and in turn, the online relation formulas between the productivity and the optimal circulating gas, and the one between the productivity and the optimal second air, were achieved respectively. These relation equations have been success- fully used in a CDQ-Boiler computer control system in the Baosteel, to realize online optimized guide and control, and meanwhile high efficiency in the CDQ-Boiler system has been achieved.

Sliding Mode Predictive Control of Main Steam Pressure in Coal-fired Power Plant Boiler

Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.

Coordinated Controller Tuning of a Boiler Turbine Unit with New Binary Particle Swarm Optimization Algorithm

Coordinated controller tuning of the boiler turbine unit is a challenging task due to the nonlinear and coupling characteristics of the system.In this paper,a new variant of binary particle swarm optimization （PSO） algorithm,called probability based binary PSO （PBPSO）,is presented to tune the parameters of a coordinated controller.The simulation results show that PBPSO can effectively optimize the control parameters and achieves better control performance than those based on standard discrete binary PSO,modified binary PSO,and standard continuous PSO.

The Development and Research on the Coordinate Control Strategy Between Turbine and Boiler in Fossil Power Plant

Based on the research on domestic and international automatic technical development in fossil power plant,the paper analyses the recent situation of the coordinate control system between turbine and boiler of domestic fossil Power Plant,provides the development thought of coordinate control system between turbine and boiler,and describes the application prospect in control system of fossil power plant combining with the application experience.

Nonlinear inversion-based output tracking control of a boiler-turbine unit

The capability to perform fast load-following has been an important issue in the power industry. An output tracking control system of a boiler-turbine unit is developed. The system is composed of stable inversion and feedback controller. The stable inversion is implemented as a feedforward controller to improve the load-following capability, and the feedback controller is utilized to guarantee the stability and robustness of the whole system. Loop-shaping H∞ method is used to design the feedback controller and the final controller is reduced to a multivariable PI form. The output tracking control system takes account of the multivariable, nonlinear and coupling behavior of boiler-turbine system, and the simulation tests show that the control system works well and can be widely applied.

AUTOMATIC TUNING OF PID CONTROLLERS IN THE THERMAL POWER UNIT LOAD CONTROL SYSTEM

A method of measuring the interactions in a multivariable control sys-tem(MVCS)in time domain is defined in this paper.An intelligent decoupling com-pensator is designed in terms of the concept of fuzzy control,so that the auto-tuningof controllers’ parameters in a 2×2 MVCS can be turned into that of two independentsingle-loop control systems(SLCS).The method presented in the paper has success-fully been used in a simulation experiment on the automatic tuning of a coordinatedcontrol system(CCS)in the drum-boiler turbogenerating unit(DBTU)and the simu-lation results axe satisfactory.

Simulation on an optimal combustion control strategy for 3-D temperature distributions in tangentially pc-fired utility boiler furnaces

The control of 3-D temperature distribution in a utility boiler furnace is essential for the safe, economic and clean operation of pc-fired furnace with multi-burner system. The development of the visualization of 3-D temperature distributions in pc-fired furnaces makes it possible for a new combustion control strategy directly with the furnace temperature as its goal to improve the control quality for the combustion processes. Studied in this paper is such a new strategy that the whole furnace is divided into several parts in the vertical direction, and the average temperature and its bias from the center in every cross section can be extracted from the visualization results of the 3-D temperature distributions. In the simulation stage, a computational fluid dynamics(CFD) code served to calculate the 3-D temperature distributions in a furnace, then a linear model was set up to relate the features of the temperature distributions with the input of the combustion processes, such as the flow rates of fuel and air fed into the furnaces through all the burners. The adaptive genetic algorithm was adopted to find the optimal combination of the whole input parameters which ensure to form an optimal 3-D temperature field in the furnace desired for the operation of boiler. Simulation results showed that the strategy could soon find the factors making the temperature distribution apart from the optimal state and give correct adjusting suggestions.

Innovation in Bio-disaster Prevention and Control Mechanism after Forest Tenure Reform at County Level

Taking Youxi County of Fujian Province as an example,the author introduced basic situations of new bio-disaster prevention and control mechanism for forest resource protection and social service works after the forest tenure reform.Then,the author analyzed new problems faced by bio-disaster prevention and control in forestry.Finally,the author present the existing problems of bio-disaster prevention and control at the county level from five aspects:innovating upon plant quarantine management mechanism;innovation upon survey methods and service modes of bio-disaster monitoring;strengthening and improving construction of bio-disaster monitoring and forecasting network;innovating upon management system for bio-disaster prevention and control;speeding up construction of service system for social prevention and control of bio-disasters.

Digital Control Design for the Boiler Drum BDT921

A boiler drum BDT921 that is installed in the Control Laboratory, Department of Mechatronics and Robotics Engineering, Faculty of Electric and Electronic Engineering, Universiti Tun Hussein Onn Malaysia （UTHM） is being used as a model plant to achieve the digital control system since its analog. Implementing a digital system to boiler quite a though work. This paper covers analysis from the experiment done to match with digital design that will be implemented to the real system. The digital control design will come up with the mathematical model and will be analyzed with MATLAB and SIMULINK software named as ＂Discrete Analysis ofBDT921 Simulation＂. A proportional integral and derivative （PID） controller is being chosen as the control element in discrete form as the real system is using the same control element. The output responses behave as the second order system with a bit difference in rise times and peak times compared with data obtained from experiment. With regarding to the analysis done, the digital control can be implemented and for further viewing, to be controlled digitally with computer in the control room.

Optimizing Two-Phase Flow Heat Transfer:DCS Hybrid Modeling and Automation in Coal-Fired Power Plant Boilers

In response to escalating challenges in energy conservation and emission reduction,this study delves into the complexities of heat transfer in two-phase flows and adjustments to combustion processes within coal-fired boilers.Utilizing a fusion of hybrid modeling and automation technologies,we develop soft measurement models for key combustion parameters,such as the net calorific value of coal,flue gas oxygen content,and fly ash carbon content,within theDistributedControl System(DCS).Validated with performance test data,thesemodels exhibit controlled root mean square error(RMSE)and maximum absolute error(MAXE)values,both within the range of 0.203.Integrated into their respective automatic control systems,thesemodels optimize two-phase flow heat transfer,finetune combustion conditions,and mitigate incomplete combustion.Furthermore,this paper conducts an in-depth exploration of the generationmechanismof nitrogen oxides(NO_(x))and low oxygen emission reduction technology in coal-fired boilers,demonstrating a substantial reduction in furnace exit NO_(x) generation by 30%to 40%and the power supply coal consumption decreased by 1.62 g/(kW h).The research outcomes highlight the model’s rapid responsiveness,enabling prompt reflection of transient variations in various economic indicator parameters.This provides a more effective means for real-time monitoring of crucial variables in coal-fired boilers and facilitates timely combustion adjustments,underscoring notable achievements in boiler combustion.The research not only provides valuable and practical insights into the intricacies of two-phase flow heat transfer and heat exchange but also establishes a pioneering methodology for tackling industry challenges.

Tuning of Coordinated Controllers for Boiler-turbine Units

A simple two-by-two model for a boiler-turbine unit is derived in this paper, which can capture the essential dynamics of the typical process. The coordinated controller is designed based on this model. A PID control structure and a tuning procedure are proposed. The example shows that the method is easy to use and can achieve an acceptable performance.

Dynamic Modeling and Simulation of a Commercial Naphtha Catalytic Reforming Process

A first principles-based dynamic model for a continuous catalyst regeneration (CCR) platforming process, the UOP commercial naphtha catalytic reforming process, is developed in this paper. The lumping details of the naphtha feed and reaction scheme of the reaction model are given. The process model is composed of the reforming reaction model with catalyst deactivation, the furnace model and the separator model, which is capable of capturing the major dynamics that occurs in this process system. Dynamic simulations are performed based on Gear numerical algorithm and method of lines (MOL), a numerical technique dealing with partial differential equations (PDEs). The results of simulation are also presented. Dynamic responses caused by disturbances in the process system can be correctly predicted through simulations.

Engineering Drawing Education Reform and Digital Technology

The way of reform and development of Engineering Drawing education is explored. Such activities have been carried out for 5 years, and great progress in the update of course contents, teaching methods and other related aspects is achieved. A series of textbooks, multimedia CD and established a Web site for Engineering Drawing course have been published. The efforts to realize an advanced contemporary teaching mode are being made. With the support of multimedia software and resources over Internet, students become the real main body of study, the teaching qualities are supervised and controlled throughout, and the students?imagination and ability of design and drawing are greatly enhanced. All reform is built on digital technology.

The Impact of Health Care Reform Initiatives on Ethical Conflict and Opportunities for Nurses to Improve Quality of Care While Enhancing Their Work Environments

Background: After more than a decade of the nursing profession contending that healthcare reform based almost exclusively on cost cutting was creating an array of serious ethical issues for nurses, healthcare organizations and other providers are now facing increasing demands primarily from payers to demonstrate improvement in both quality of care and patient experience along with continued cost reduction. Research Question: Have efforts by healthcare organizations to comply with these recently imposed requirements influenced the ethical environment faced by nurses and nurse leaders and if so, how? Materials and Methods: Data for assessing the current ethical environment was gathered with a close-ended survey mailed in October 2012 to a random sample of 3000 members of the American Organization of Nurse Executives. Results and Discussion: Statistical analysis of the data and comparison with the findings of a similar study conducted in 2000 indicated that along with five highly rated issues in the earlier study attributed largely to economic constraints imposed by healthcare organizations, the top-10 key ethical issues today included five issues primarily attributable to interprofessional conflict. Conclusion: Given the success of many ongoing efforts aimed at weakening these key sources of ethical conflict that have blocked many proposals to improve the quality of care, opportunities should arise for the nursing profession to more fully achieve its goals of improving the quality of care, safety and patient satisfaction and enhancing nurses’ work environments essential to that effort.

Smart Boilers: Grid Support Services from Non-Critical Loads

The aim of this paper is to present the concept of a simple and cheap upgrade for electric water boilers, allowing them to provide power quality services to the distribution grid. The upgrade requires only minimum additional hardware and it is easily installable. “Smart Boilers”, as the upgraded boilers are named, perform precise active and reactive power control, but most significantly mitigate line current harmonics. Αctive and reactive power control is implemented by appropriate regulation of the modulation sinewave amplitude and phase, respectively. This type of control is easily customizable in order to accommodate a variety of power quality targets, depending on the required level of services and available grid monitoring equipment. The method used for line current harmonic compensation is based on the injection of mirror harmonics created at the modulation stage of the converter. It is indifferent of harmonic source: it is equally successful at mitigating harmonics caused by the power electronic converter of the Smart Boiler, other sources of current harmonics or loads. The achieved grid services are clearly beyond the “on/off” operation of electric boilers, currently implemented by Demand Side Management (DSM) in order to shift load away from peak hours. It has been demonstrated through simulations, that Smart Boilers can assist voltage regulation at terminal buses, compensate reactive power and suppress harmonic currents at lines.

Analysis on Frequent Flameout of HG-1025/18.2-YM6 Boiler

Based on reason analyses for frequent flameout of HG-1025/18.2-YM6 boiler in a given power plant after coal quality variation, major factors such as unreasonable burner structure and inappropriate secondary air distribution were discussed in detail. A new mode of secondary air distribution was introduced to optimize the combustion performance, and a lower burner was retrofitted by increasing the relative distance between the primary air fuel rich-lean nozzles and reducing the size of waist air nozzles as well. As a result, the recirculating zone became more stable and the burner's combustion stability was improved.Practical operation shows that the modifications are so effective that the flameout problems caused by instable combustion never occur in operation.

Work Boilers in the Real Heat Loads

Analysis was performed on the boiler for solid fuels in a corresponding real-thermal load. The tests were conducted with the use of a low-temperature top-loading KWSM water boiler. For control of the burning process, three control algorithms were used as implemented in microprocessor temperature controls. The analysis aimed at determination of influence of the control algorithm upon quality of the buming process in conditions of actual demand for thermal energy. The detailed analysis of operating parameters in relation to the variable thermal load of the boiler provided necessary information and made it possible to state that control algorithms do influence quality of the controlled process. Particular attention was paid to a situation, in which demand for thermal energy is decreased.