In order to solve the problem of real time inspection of coal quality for utility boilers

a calculation model for boiler efficiency was established

from aspects of positive balance and anti-balance

on the basis of mass balance theory and coal combustion chemical analysis.The relationship between coal element ingredient and flue gas ingredient was obtained.On this basis

the coal quality soft-sensing model for utility boilers was built up.Adopting the actual operation data of a power plant when the coal quality is stable

the ultimate analysis and calorific value of the coal were calculated

and the simulated results were compared with the test data.The results show that

the relative error of the ultimate analysis and net calorific value of the coal between the simulation results and test data is within ±5%.