To alleviate the slagging in furnace of boiler firing high sodium coal

coals with weak fouling ability were co-burned. This paper discussed the calibration of temperature measurement system based on color CCD temperature detection system

and studied the influence of defocus and exposure time on temperature measurement accuracy by blackbody furnace. The flue temperature at furnace outlet of a 660 MW unit ultra-supercritical boiler was measured when burning blended Shenhua coal. The changing of furnace outlet temperature with furnace sootblowing and the temperature rise rate at furnace outlet were also obtained under different blending schemes. Furthermore

a method was put forward for monitoring the furnace blending at fixed load. The results show that

the maximum deviation of the temperature measurement system is within 1.48% within the range from 950 ℃ to1 250 ℃

which is within engineering permissible error range. The temperature change and rise rate of furnace outlet of the blending scheme 4

5 are obvious higher than that of the scheme 1

2 and 3

which illustrates that the higher blending ratio of Shenhua coal

the more serious of slagging in the furnace

and the ratio should be less than 80%. When running in full load condition

the boiler should put 5 coal mills into operation

of which

mill A taking in Baoli coal

mill B to mill E taking in Shenhua coal

and the time interval of furnace soot-blowing is 15 h.