On-line calculation model for thermal efficiency of coal-fired utility boiler based on heating value identification

Thermal efficiency of coal-fired utility boiler is an important indicator used to measure economic operation of power plant. However, on-line calculation for thermal efficiency of boiler still have difficulties, which the coal quality are often changing and not well obtained real-time. This paper identify the heating value of the coal into the boiler, aiming at the on-line calculation of the boiler efficiency, by means of the dynamic mass and energy balance method. Then an on-line calculation model for thermal efficiency of the boiler was established based on the indirect heat balance method. The paper illustrates the effectiveness of the models as well as the validation of the on-line simulation, starting from real operation data. The outcome is that it is possible to significantly satisfy the accuracy of on-line identification of the Low Heating Value (LHV) of the coal into the boiler, and the real-time of on-line calculations provided by indirect heat balance method. The models can be used to the real-time control and optimization of the coal-fired utility boilers.