The study of the effect of gas-phase fluctuation on slag flow and refractory brick corrosion in the slag tapping hole of an entrained-flow gasifier

Abstract

The effects of gas-phase fluctuation on the brick corrosion process were studied in this work in order to investigate the corrosion mechanism of refractory brick in the slag tapping hole. The results explained the reason for the low service life of the refractory brick of the slag tapping hole in the commercial gasifiers. It was found that when the low-frequency fluctuation changed to the high-frequency fluctuation, the brick corrosion rate decreased gradually. Compared with the gas-phase velocity fluctuation, the gas-phase temperature fluctuation had a more significant influence on the brick corrosion rate. • The effect of gas temperature and velocity fluctuation on slag flow was studied. • Low-frequency fluctuation had a significant effect on the brick corrosion rate. • The brick corrosion rate increased with the increase of temperature fluctuation. The service life of refractory brick in the slag tapping hole of the entrained flow gasifier was significantly lower than that in other locations. It was critically important to study the corrosion mechanism of refractory brick in the slag tapping hole for guiding industrial production. Considering the complex flow field in the slag tapping hole, the influence of gas velocity and temperature fluctuation on the service life of refractory brick was investigated in this study. The results showed that the slag flow characteristics periodically changed with the gas temperature and velocity fluctuations. The brick corrosion rate increased with the decrease of fluctuation frequency. Compared with the gas-phase velocity fluctuation, the gas-phase temperature fluctuation had a more significant influence on the brick corrosion rate. When the fluctuation frequency was 0.01 Hz and the gas temperature fluctuation amplitude was 200 K, the corrosion rate of refractory bricks increased by 25%. It could be concluded that the fluctuation of gas-phase temperature was the main cause for the low service life of refractory bricks in the tapping hole.