Analysis on the temperature deviation of water wall of a W-flame boiler and the treatment

Abstract

Due to the sharp and long-term water wall temperature deviations in a 600 MW supercritical W-flame boiler in a power plant， the units had to operate with reduced parameters. A comparison of the temperature of the upper and lower water walls with the design parameters revealed that： the thermal deviation of the upper water wall of the furnace was severe； the deviation of the front wall temperature was mainly generated in the upper chamber； the uneven outlet wall temperature that led to the deviation of the thermal efficiency flow aggravated the front wall temperature. In order to improve the evenness of the heat load distribution in the furnace， the coal distribution of the coal mill was optimized according to the current coal storage， and the blending ratio of the high and low calorific value blending bunkers was adjusted according to the local wall temperature. In view of the existing “front wall pressing back wall”， the F-layer secondary air distribution had a negative impact on the heat absorption of the water walls on the side walls. Therefore， the opening of the secondary dampers on the back wall against both walls was reduced to improve the heat absorption of both walls. After the adjustment， the temperature difference of the front walls was reduced， the main steam temperature increased， and the desired effect was achieved.

Keywords

• w-flame boiler
• water wall
• wall temperature deviation
• coal blending optimization
• secondary air optimization