The Operation Optimization Of Power Plant Pulverized Coal-Fired Boiler Based On Thermodynamic Calculation

Pulverized coal-fired boiler is an important equipment in thermal power plant, which determines the operation cost of the whole plant. The boiler's operation optimization is an effective method to save energy, reduce consumption and raise energy efficiency, and it can improve boiler's combustion efficiency and reduce coal consumption of power plant, thus the competitive power of power enterprise is greatly improved.A 130t/h pulverized coal-fired boiler is studied in this paper, and the boiler's thermodynamic calculation theory and method are analyzed comprehensively. The thermophysical properties of fluids (flue gas, air, water and vapour) and the heat transfer law of heat transfer units such as combustion chamber, overheaters, reheaters, economizers and air preheaters are studied. The involved objects in thermodynamic calculation such as the fuel, heat transfer units and fluids are classified and researched, and the relationship between them is also studied, thus the modeling is completed. Based on the model analysis, the programming language Visual C++ is used as a development tool and the object-oriented programming method is adopted to design the heat tranfer unit classes, fluid class and auxiliary class. The standard calculating module of the fluids'physical properties and the calculating class module such as the convective exothermic coefficient at the side of flue gas are programmed. At last, by the use of numerical iterative algorithm, the automatic iterative process of boiler's thermodynamic calculation is achieved.The optimization model of the 130t/h pulverized coal-fired boiler is built, and the objective function of the boiler's operation optimization and the independent variables that determine the objective function are decided, also the constraints of the model are determined. On the basis of the boiler's thermodynamic calculation, the software of boiler's operation optimization is developed. On condition that the boiler operates safely, the optimization model of boiler's operation (coal blending optimization and air distribution optimization) is solved by exhaustive algorithm, and then the boiler's coal blending ratio and excess air ratio are obtained when the boiler operates economically, so the optimization goal that the heat generating cost is the lowest is achieved.By the example of the 130t/h pulverized coal-fired boiler's operation optimization, the influence of coal blending ratio and excess air ratio on the boiler's operation is analyzed.