Abstract: A precise physical model is developed for the tiny-oil ignition burner in a 330 MW tangentially-fired boiler, including the primary air, the surrounding air and the burner thick wall areas. The three dimensional numerical simulation on the fluid flow process, combustion and fluid-solid coupled heat transfer in these areas are conducted under the bituminous coal combustion conditions. The effects of oil gun flow rate on the ignition performance and the wall temperature are carefully analyzed for the oil flow rate optimization. The calculated temperature matches well with the measured value at the monitoring points. The calculated results show that appropriate oil flow rate reduction not only has little side effect on the ignition performance, but also can lower the wall temperature of the burner. Theoretically the oil flow rate should be kept at 70 kg/h as the minimum requirement for the coal type of the boiler. In practical operation it can be adjusted to 80 kg/h to ensure sufficient secure margin. According to the practical operation data, with the oil flow rate at 80 kg/h, although the maximum and average temperatures at the burner exit have all been somewhat decreased, the operation parameters and indices of the boiler still remain normal and meet all the requirements for successful ignition.

Key words: tiny-oil ignition burner, bituminous coal, oil flow rate optimization, numerical simulation