Boiler Control System Research Articles

Research on Mechanical Engineering with the Design and Implementation of Thermal Power Boiler Soot Blowing Control System

Ash deposition and slagging on boiler heat exchange surfaces is a common phenomenon in fossil fuel fired power plants. In this dissertation, author focuses on the building of soot blowing control system and all of the work is based on a 300MW boiler. This dissertation introduces the endangerment of soot deposition on boiler heat exchange surfaces. In order to reduce the loss due to fouling of the heat exchange surfaces and improve the economic efficiency of the boiler. In this dissertation, author finds the reason about the fouling form and makes analysis on the damage about the soot to thermal power boiler. On the other hand, author make design and implementation of the thermal power boiler soot blowing control system including hardware system design and software system design, and it will be the fundament of soot blowing optimization. The hardware can connect the equipment about the boiler together, and it is the foundation of the control system for thermal power boiler. Based on the data from DAS of power plant and using heating balance theory, this software system puts forwards some graphical user interfaces and that can configure the setting data and monitor the information about thermal power boiler. In this dissertation, author will design and realize the control system about thermal power boiler.

Determination of transient fluid temperature using the inverse method

Abstract This paper proposes an inverse method to obtain accurate measurements of the transient temperature of fluid. A method for unit step and linear rise of temperature is presented. For this purpose, the thermometer housing is modelled as a full cylindrical element (with no inner hole), divided into four control volumes. Using the control volume method, the heat balance equations can be written for each of the nodes for each of the control volumes. Thus, for a known temperature in the middle of the cylindrical element, the distribution of temperature in three nodes and heat flux at the outer surface were obtained. For a known value of the heat transfer coefficient the temperature of the fluid can be calculated using the boundary condition. Additionally, results of experimental research are presented. The research was carried out during the start-up of an experimental installation, which comprises: a steam generator unit, an installation for boiler feed water treatment, a tray-type deaerator, a blow down flashvessel for heat recovery, a steam pressure reduction station, a boiler control system and a steam header made of martensitic high alloy P91 steel. Based on temperature measurements made in the steam header using the inverse method, accurate measurements of the transient temperature of the steam were obtained. The results of the calculations are compared with the real temperature of the steam, which can be determined for a known pressure and enthalpy.

Smith-ADRC for Main Steam Pressure of CFBB

The main steam pressure control is one of the most important parts in Circulating Fluidized Bed Boiler (CFBB) control system. However, it is difficult to design controller because the combustion system of CFBB is an object that has many features: distributed parameters, nonlinear, time-varying and long time-delay. Therefore, in this paper, Smith-Active Disturbance Rejection Control (ADRC) is proposed and simulation results demonstrate the Smith-ADRC is effective in main steam pressure control.

Temperature Control System Based on Intelligent Electronic Boiler

The electric boiler in use at present has a significant system inertia and a serious time-lag at the same time the difficulty of building the mathematical model. We often use PID algorithm of integral separation to improve the system. In this thesis, we put forward another PID algorithm of alteration in rate and take the example of the temperature control system of electric boiler. Then we use digital simulation of control system based on MATLAB to The method of fuzzy PID control is a ideal method.

Development of an air fuel control system for a domestic wood pellet boiler

Wood pellets are a kind of solid biomass energy and a renewable energy source. Made by compressing sawdust, wood pellets have a higher energy density than split firewood and wood chips. In 2007, the new and renewable energy (NRE) portion was 2.4% with respect to total primary energy in Korea. The Korean government wants to increase the new and renewable energy (NRE) portion up to 6.1% by 2020 [1]. To achieve this target, the government has been establishing some policies, such as incentive policy, NRE mandatory use for public building and renewable portfolio standard (RPS) and so on. To supply wood pellets as fuel for the combustion chamber of a wood pellet boiler, most domestic wood pellet boilers put a constant volume by using an auger type fuel feed system. In an auger system as fuel feeding, there is the possibility of changing energy input due to the different density of wood pellets even in a constant volume flow rate of wood pellets. If fuel input rate is changed without any correction of air flow rate for combustion, the condition of combustion in a wood pellet boiler can be deteriorated. We have developed an air-fuel control system for a domestic wood pellet boiler by using flue gas oxygen concentration measurement and a PID controller. To measure O2 concentration of flue gas, a wide band O2 sensor was adopted. We changed fuel input from 100% to 50% by artificial manipulation to confirm the control system. The O2 concentration in flue gas can be controlled to be 8.5% ± 1% without significant change of CO and NOx concentration.

Invariant Method of Load Independent Pressure Control in Steam Boiler

Abstract The paper considers the possibility of steam production and supply process improvement by perfection of the steam boiler control system, applying invariance principle that makes possible preemptive compensation of the influence of steam expenditure as a disturbance on the control process quality and efficiency. For the development of invariant control system, the mathematical modeling and simulation in MATLAB - SIMULINK environment is made. The control unit is low pressure steam boiler with one input impact to control - the heat flow of burning gas mixture fuel, one measured output parameter of the process - the steam pressure, and the main disturbance as a load impact - the steam expenditure. The mathematical and virtual models and block-diagrams for transient process simulation is compiled, allowing to start practical design and investigation of steam boiler invariant control system with high operation stability under essentially fluctuating load. The simulation results prove that the optimal solution for the transient process improvement in steam boiler, taking in account fluctuating load, is invariant PID-DPC two loop control system with disturbance impact on steam pressure preemptive compensation. Under invariant control the steam pressure overshoots decreases substantially in comparison with the traditional PID-feedback control method.

The Water Level of Marine Boiler Control and Simulation System Based on Compensatory Fuzzy Neural Network

The Water Level of Marine Boiler Control and Simulation System Based on Compensatory Fuzzy Neural Network

Fault Diagnosis for Level Control System Based on IDEF

In order to improve the dynamic stability of level control system in the steam drum of boiler, a fault diagnosis approach is proposed by using IDEF method, which can analyze the control system structure by the IDEF model. When the faults occur, the possible causes of fault can quickly be identified by using the model. The approach can provide a reliable basis of decision-making for the control and make a reasonable fault diagnosis in a timely and accurate manner. Using the method can effectively improve the speed of fault diagnosis, prevent the fault occurs, ensure safety and stable operation for the boiler control system.

The Power Plant Boiler Automatic Control Based on PLC

The power plant boiler automatic control system is designed on the basis of Siemens S7-200 in this paper. Based on the introduction of the Siemens S7-200 and the works of the boiler, the total power plant boiler control system is designed in details. Besides the initialized program is designed based on the input and output address of all the switches. The communication program is achieved, including the initialization of the program running parameters, the call of the system subroutine, the calculation of the checksum, the real-time data receiving process, etc. Finally, the heat energy is successfully and automaticly converted to the electricity in the boiler based on the PLC.

Web-Based Heating Boiler Control System Research

Aiming at the defects of traditional heating boiler control systems, in Geographical limitations, waste of human resources etc. We combines Web technology with traditional heating boiler control strategies, developed a B/S,C/S mixed-mode control system, that allows workers look up data and control heating boilers from Website safely, no matter where the heating boiler located. Website is developed in ASP.NET, other programs are developed in VC++.NET. This system can improve management and production efficiencies, reduce human resources and operating costs.

Model-Free Adaptive PID Controllers Applied to the Benchmark PID'12

Many tuning strategies for PID control algorithms have been proposed in the literature depending on modeling choice from heuristics, physical laws and/or experimental essays. In this paper, the properties of three model-free adaptive PID control design conceptions, known as direct PID control, are investigated and implemented. The recursive least squares estimator is used to identify the PID controller gains without the knowledge of the plant mathematical model. The tuning strategies of the direct PID controller are applied to the boiler control system proposed by Fernando Morilla (UNED, Spain) as a benchmark problem for the 2012 IFAC Conference on Advances in PID Controllers.

The Application Design of the Heating Boiler System

This paper introduces the design of a heating boiler control system based on PLC and IFIX. In this system, combining Premium PLC with IFIX4.5, industry Ethernet TCP/IP protocol communication is adopted to constructer the monitoring system of heating boiler though PLC and PC. Unity4.0 is used to design the ladder diagrams for the coal burning boiler to automatically realize burning process control and hearth pressure adjustment. IFIX4.5 is adopted to develop supervision control programs, which have perfect function, handy operation, fine visualization and strong man-machine interface.

Modeling and Simulation of Interconnected CFB-boiler and Fast Pyrolysis Processes – Control Design Case

AbstractThe fast pyrolysis process is developed to produce liquid bio oil from biomass. In the discussed process the required thermal energy is extracted from a circulating fluidized bed boiler (CFB) as hot sand fed into the pyrolysis reactor. Residual char and uncondensed gases from the pyrolysis process are fed back and combusted in the boiler. Thus, the pyrolysis and the boiler processes are interconnected together both via energy and mass balances. Dynamic simulation is used to analyze how start ups, stops, and disturbances in the pyrolysis process effect on the operation of the boiler. According to the results of the analysis the boiler control system is modified to be able to stabilize the operation of the boiler with the interconnected pyrolysis process. The trouble free operation of the boiler must be guaranteed during all possible situations of the pyrolysis process. This project is a part of a R&D project by Metso Power where fast pyrolysis process is developed and commercialized as a new liquid bio fuel production process which can be integrated e.g. as a part of a paper mill.

Backstepping-based nonlinear adaptive control for coal-fired utility boiler–turbine units

The control system of boiler–turbine unit plays an important role in improving efficiency and reducing emissions of power generation unit. The nonlinear, coupling and uncertainty of the unit caused by varying working conditions should be fully considered during the control system design. This paper presents an efficient control scheme based on backstepping theory for improving load adaptability of boiler–turbines in wide operation range. The design process of the scheme includes model preprocessing, control Lyapunov functions selection, interlaced computation of adaptive control laws, etc. For simplification and accuracy, differential of steam pipe inlet pressure and integral terms of target errors are adopted. Also, to enhance practicality, implementation steps of the scheme are proposed. A practical nonlinear model of a 500 MW coal-fired boiler–turbine unit is used to test the efficiency of the proposed scheme in different conditions.

The Cascade Three-Elements Fuzzy Auto-Adapted PID Control System for Boiler

Medium and Small boilers, which are widely used, are common power equipments in power plants, Smelters, and chemical plants, and important to the safety and production of enterprises. In this paper, the main factors affecting the changing industrial boiler water level have been analyzed, and relevant control theory been studied. A cascade three-impulse supply water Fuzzy-PID control system and the implement of Fuzzy-PID control formula based on IPC and PLC have been introduced .The results of the simulation indicated that the design can overcome the illusive water level and can improve the performance of the system obviously. The cascade three-element feedback control system using IPC and PLC as the center control unit, combining the fuzzy control with the conventional PID control, obtains both virtues of the high precision of PID and the flexibility and adaptability of the fuzzy control.

Potential of Process Energy Optimization (PEO)TM on a Soda Ash Production Plant

ABSTRACT An energy audit was conducted on a soda ash plant in Botswana, and it was found that the performance of the plant could be improved. Further investigation revealed that the performance of the carbon dioxide (CO2) production section was heavily influenced by control problems experienced at the two coal-firing boilers. The CO2 production section consumes energy in the form of steam and electricity and utilizes a solvent mono-ethanol-amine (MEA) to extract CO2 from boiler flue gasses. Recommendations were made to repair and re-commission the boiler control system and to install an energy optimization system. Annual savings that could be achieved by optimal control of steam from the boilers to the turbine, CO2. plant, and processing plant (thereby controlling the interactions between these sections) amounted to BWP 2, 6 million. This constitutes 10% of the total annual coal bill. A total project life cycle of only 5 years was used, and the escalating savings due to inflation was disregarded. The IRR ...

Assessment of boiler tubes overheating mechanisms during a postulated loss of feedwater accident

Due to their simplicity and passive nature, natural circulation loops have many industrial applications and being increasingly used in many innovative designs as the new generation of nuclear reactor cooling systems. Consequently, special attention is increasingly considered towards their safety issues. In the current framework, a safety aspect related to the loss of feedwater in an industrial D-type steam boiler is assessed. Indeed, loss of feedwater event occurs frequently during steam generator facilities lifetime. Under such conditions, the system integrity is in jeopardy and serious hazards and economic losses could occur. Up to now, specific numerical models have been used to simulate the thermal-hydraulic phenomena occurring under such circumstances. Such models are generally based upon simplified assumptions, and if complex model are performed, their applications are generally restricted to the facility they have been developed for. In the current framework, an attempt is made to apply a multipurpose best estimate (BE) thermal-hydraulic system code, namely, RELAP5/Mod3.2 to simulate steady-state and transient dynamic behaviors of a two-phase natural circulation steam boiler. For this purpose, two loss of feedwater scenarios, with and without the actuation of the boiler control system, have been performed. The analysis results show on one hand the achievement in applying RELAP5 for a conventional boiler system, and on the other hand the efficiency of the control systems to mitigate the accident consequences.

Improvement of Load-Following Capacity Based on the Flame Radiation Intensity Signal in a Power Plant

The capability to perform fast load changes has been an important issue due to the increasing commercialization of the power market. In the traditional boiler control system, the feedback signals come from the variations of the steam pressure and the steam flow, which leads to a large time delay. Therefore, a new method for the boiler control system based on radiation intensity for improving the load-following capacity of a coal-fired power plant has been developed in this paper. The system is implemented by adding the radiation intensity of the flame to the existing boiler control system as a complement. The radiation intensity obtained by the sensor can directly reflect the input heat in the boiler, with a faster response and higher sensitivity. Field tests on a 300 MW coal-fired power plant reveal that the improved boiler control system increases the load-following capacity. At the same time, the steam pressure variations are smaller as compared with those of the existing control system. 14 refs., 19 figs., 1 tab.

A26: Steam boiler thermal environment protection system

This paper deals with the problem of technological process control systems modernization in Lietuvos Elektrine AB. There was analyzed a structure of existing steam boilers. There are presented requirements for steam boiler control system. There are listened thermal environment protection features and usage principals for PLC based protection system

Optimal boiler control through real-time monitoring of unburned carbon in fly ash by laser-induced breakdown spectroscopy

A laser-induced breakdown spectroscopy (LIBS) technique has been applied for detection of unburned carbon in fly ash, and an automated LIBS unit has been developed and applied in a 1000-MW pulverized-coal-fired power plant for real-time measurement, specifically of unburned carbon in fly ash. Good agreement was found between measurement results from the LIBS method and those from the conventional method (Japanese Industrial Standard 8815), with a standard deviation of 0.27%. This result confirms that the measurement of unburned carbon in fly ash by use of LIBS is sufficiently accurate for boiler control. Measurements taken by this apparatus were also integrated into a boiler-control system with the objective of achieving optimal and stable combustion. By control of the rotating speed of a mill rotary separator relative to measured unburned-carbon content, it has been demonstrated that boiler control is possible in an optimized manner by use of the value of the unburned-carbon content of fly ash.