Study on fuel bias combustion swirl technology of a 1025 t/h pulverized coal fired boiler

With the enhanced ignition-dual register burner (EU-DRB), a 1025 t/h coal-fired boiler could not achieve a stable flame when burning the low-grade coal. Experiments on a single-phase test facility and the boiler were done to solve the problem. A bias combustion pulverized coal swirl burner matching the boiler is gotten. Experiments show: the ratio of the largest diameter and length of the central recirculation zone to the outer diameter of the burner are over 1.15 and 1.83, and the flow divergent angle is over 70.1°. This central recirculation zone can provide enough high temperature gas to ignite pulverized coal. The higher the ratio of the non-swirl secondary air is, the lower the gas temperature in the burner region is. The EI-DRB has no the central recirculation zone. It is disadvantage to the flame stabilization. The influence of the rotational speeds of the feeder on the distribution of the gas temperature in the burner region is gotten with two types of burner. With the burners, the boiler operates stably at 135 MW.