EXPERIMENTAL STUDIES ON SLAGGING AND FOULING CHARACTERISTICS DURING ZHUNDONG COAL COMBUSTION

摘要

Zhundong coal is rich in reserves and with unique characteristics, but it can not be transported out cosmically for the geographical, economic and transportation conditions. It is seriously hampered the application of Zhundong coal. At present, some power plants in Xinjiang have partially or completely burned Zhundong coal. However, due to severe slagging and serious contamination characteristic of Zhundong coal, the heating surfaces of the boilers in these power plants encounter severe slagging and serious contamination problems and the units can not keep long-term safe operation. Therefore, it is necessary to carry out studies on slagging and fouling characteristics of Zhundong coal.rnThe slaggging and fouling characteristcs of Zhundong coal are investigated by a 0.65MW pulverized coal combustion test platform. During the experiment, a new type of Zhundong coal swirl burner was adopted. The slaggging and fouling characteristcs of Zhundong coal in swirling combustion are mainly deliberated, especially the influence of the coal fineness. Furthermore, the slag samples and ash samples in different combustion regions were characterized by XRD, XRF, SEM, and EDS analysis. The results showed that the slagging of Zhundong coal has important relationship with coal fineness, and there is an optimum range of coal particle size which can reduce the slagging and also reduce the tail heating surface contamination. Additionally, the slagging mechanism in the furnace is selective deposition of calcium iron while the fouling mechanism in the tail heating surface initiates selective deposition of alkali metal element sodium.rnThe research achievments have important guiding significance for the design of partially or completely burning Zhundong coal boiler as well as its long-term safe and efficient operation.