Mechanism of pipe expansion in a 600 MW W-shape flame boiler

Because a 600 MW supercritical W-shape flame boiler of a power plant has a problem of frequent pipe expansion, numerical simulation of the boiler on combustion process was conducted to study the effect of pipe expansion with different loads, coals and air distributions. The results show that the temperature field is significantly skewed and the temperature flame sweeps over heating surface seriously in 450 MW, which may lead to the pipe explosion of the heating surface. The flame center is low and flame washes cold ash hopper seriously in 300 MW, which may lead to pipe explosion of the cold ash hopper heating surface. The different coals have different flame centers, which may cause combustion shock and make the heating surface have a large temperature gradient to pipe expansion. Different air distributions also affect the flame center, which may cause pipe expansion.