Research On The Theory And Technology Of Combustion Optimization Based On Boiler Parameters Measurement

The cost of fuel accounts for more than70%in all thermal power costs, so it is of great significance to raise the running level of combustion system of utility boilers.Besides, power generators are faced with the competition of separation of plant and network and biding for use of network, and energy shortage causes the price rise of coal. All these make the thermal power costs greater. As the State put restrictions on power plant emissions, the technology of how to effectively reduce emissions becomes the focus of power plants.Domestic coal-fired power plants are confronted with two requirements to improve boiler efficiency and lower pollution emission because of the rising coal prices and pollution emission limits, thus there is an urgent need for a method of optimizing the process control and schedule. This method can meet the needs of energy saving, consumption reducing, pollution lowering and safe operation.The optimization technology of combustion system for utility boilers can improve unit operation efficiency, reduce power-generation costs, reduce the emission of pollutions significiently, and safeguard the safe operation of the boiler. This dissertation puts the combustion system for the study, and discuss the theories and techniques for the optimization of combustion of utility boilers. The main content includes:1. Study on techniques and methods of boiler parameter measurement.The goal of combustion optimization is to optimize boiler air distribution, coal distribution and operation mode in real time on the basis of the load and the coal, to guide the combustion regulation, so as to improve the operation efficiency of boiler combustion, reduce coal cost and the emission of NOx, and achieve economic environmental operation of utility boiler.To achieve this goal, the first problem is what kind of measuring instrument to be used to detect the main paremeters inside the boiler in real time, so as to guide the boiler combustion regulation according to these parameters.This dissertation takes the laser measurement system ZoloBOSS from Zolo technologies, Inc. as the instrument of parameter measuring, and combined with our self-developped optimization station to consist of combustion optimization system for utility boiler.2. Modeling of combustion system of utility boiler based on RBF neural network.The factors that influence NOx emissions in combustion process and the boiler efficiency are very complex, interrelated and mutually coupled, so it is quite difficult to set up a model for combustion which conforms to the current boiler characteristics by use of theoretical method. This dissertation introduces the advanced artifical intelligence neural network technology,and establishes prediction models of thermal efficiency and NOx emissions of utility boilers by RBF neural network on the basis of historical data in the combustion process, and verifies the accuracy of the model based on experimental data.3. Thermal economic analysis of lignite drying with boiler flue gas dryer.Lignite Pre-drying can obviously improve the power generation efficiency of directly lignite-fired power plant, and rotary drying is the earliest application lignite pre-drying method. Therefore, a theoretical economic analysis model for lignite-fired power generation system with boiler flue gas dryer was established in this dissertation, with which a case study on a600MW power generation system was conducted to analyze the factors influencing thermal efficiency.Combining the analysis results with combustion optimization system can improve the thermal efficiency of lignite-fired power plants in a large degree and realize energy-saving purposes.4. Parameter optimization of combustion system based on multi-objective genetic algorithm NSGA-Ⅱ.Particle Swarm Optimization Algoritthm is employed to optimize the operation parameters of boiler after we obtain boiler combustion model. The results show that the method came up with in this dissertation can give practical optimum solution of adjusting parameters such as air throttle opening, and keep the boiler in a good working condition and achieve the purpose of energy saving and emission reduction. This can provide effective solutions for thermal generators to realize high-efficiency, low-emission operation.