On-line Calculation for Thermal Efficiency of Boiler

Real-time data of boiler thermal efficiency can really reflect the boiler operation condition, heat generation and heat loss. How to overcome difficulties of the boiler efficiency on-line calculation and success in calculating the boiler thermal efficiency on line are the main concern of operation departments of power systems. Considering the difficulties of the conventional method, such as not directly obtaining the actual excess air coefficient and fly ash carbon content value in each gas discharge line, a new method is introduced on the basis of conventional method in this paper. The new method mainly uses the quality and heat balance between the air preheater gas side and air side to get the excess air coefficient at place of exhaust gas by calculating air leakage coefficient of air preheater. The main factors of fly ash carbon content are analyzed in this paper, so as to utilize BP neural networks for dynamic fitting fly ash carbon content value. In addition, the new method was checked up according to online data of some coal-fired boiler, which indicates the method can satisfy the request of practical application.