Research On Combustion State Monitoring Of Large Circulating Fluidized Bed Boiler

The combustion technology of circulating fluidized bed boilers is clean and efficient technology. There is a unique advantage of direct desulfurization and combustible fuel by using inferior coal, and there are the characteristics of economic and environmental protection. It is the focus of domestic and foreign development of clean coal combustion technology. But the essential distinction between the combustion mechanisms with pulverized coal furnace, the properties of combustion systems are large inertia, and multiple variables are strong coupling. It is difficult to effective control. Based on the combustion of environmental protection and economy as the goal, to solve multiple coupled, nonlinear, large delay problems of the system, and construct key state signals in the combustion process. To get the optimal optimization method for air with coal and optimization method of calcium with sulfur ratio of boiler, the paper mainly does the following work:Firstly, for the coupling of CFB boiler combustion system variables, research on the combustion mechanism model of carbon particle in the circulating fluidized bed boiler, analyzes and calculates multiple parameters which affect the boiler combustion state using mechanism analysis and the grey relational degree algorithm. Selecte auxiliary variables which are closest related with the tectonic state monitoring parameters from a number of variables, and the simulation results prove the validity of the method;Secondly, for the large delay and inertia of CFB boiler combustion system, based on extended kalman filter information fusion technology to construct a kind of unique"Burning carbon" state monitoring model for CFB boiler combustion system. And put forward a kind of optimization method of air and coal based on the balance of "Burning carbon". Structure dynamic heat signal of circulating fluidized bed boiler based on"Burning carbon" parameter and total air flow. To stabilize "Burning carbon" in the furnace as the premise, optimize and calculate the air and coal ratio.By using actual data of a circulating fluidized bed boiler to simulation, the results show that there is good prediction ability for the structure model, the model is proved validity, and can improve the stability and economy of CFB boiler combustion system;Then, for CFB boiler desulfurization is implemented during the combustion process, the SO2parameter is large delay and emission instability.So that construct a unique "Active limestone" state monitoring model of CFB boiler. And put forward a kind of optimization method of calcium and sulfur based on the balance of "Active limestone". Structure the SO2prediction model based on coal, air and "Active limestone". By using actual data of a circulating fluidized bed boiler to simulation, the results show that is the validity of the "Active limestone" state monitoring model.Through the real-time monitoring the changes of "Active limestone" quantity, adjusts the Ca/S ratio, optimizes of the calcium and sulfur ratio, stabilizes SO2emission concentration, and can improve the economy and environmental protection of the CFB unit;Finally, the above-mentioned research results are successful applied to600MW supercritical CFB unit in the combustion system. After analysis operating characteristics and combustion characteristics of the supercritical CFB unit, designs the dynamic heat model and the air with coal optimization method based on "Burning carbon" and can be applied to a supercritical CFB boiler. And designs the SO2prediction model and the calcium with sulfur optimization method based on "Active limestone". The experiments prove that is validity of the structural models and the proposed methods.