Application of centrally fuel rich swirl burner on a 1025 t/h bituminous coal fired boiler

An opposite-wall-fired 1025 t/h boiler burning bituminous coal have the following problems: No stable flame at low load and appearing interference easily between adjacent burners. To solve these problems, small scale cold flow experiments and full-scale industrial experiments were both performed. Eight enhanced ignition-dual register (EI-DR) burners in the bottom row of the furnace were retrofitted to centrally fuel rich (CFR) swirl burners. The results show that with the outer secondary air vane at 357deg;, the central recirculation zone of CFR burner can prevent the adjacent jets flows from interfering with each other, and be advantageous for the coal ignition and flame stability. However, for the EI-DR burner, no central recirculation zone is formed at the rated condition. Compared to that with the EI-DR burners, along the jet direction in the central region of the burner, the gas temperature with the CFR burner is higher and has a faster rising rate. The mean concentrations of O₂ and NO_x are lower. In the region near the side wall, the mean O₂ concentration is higher and the gas temperature is lower. After the eight burners in the bottom row being retrofitted, the thermal efficiency of the boiler increases by 1.03%, the NO_x emission decreases by 13.74% and the boiler operates stably rated at rating load 110 MW without auxiliary fuel oil.