Abstract:Lignite, also known as Chai coal, is the lowest coal rank coal, a brown, black and luster low grade coal between peat and bituminous coal. Chemical reactivity is strong, easy to weathering in the air, not easy to store and transport, and air pollution is serious when burning.To study the burning characteristic of lignite coal in 300MW circulating fluidized bed boiler, performance tests are conducted on mix-burning of lignite and anthracite with different proportions. Tests indicate that: with increasing proportion of lignite, overall efficiency of the boiler increases, but burning efficiency of anthracite itself decreases. Under mix-burning, the highest comprehensive benefit will be achieved in a proportion of 3：7 (anthracite: lignite). With increasing proportion of lignite, there is also certain increase of NOx; when under pure burning of lignite, emission of NOx can be controlled below 200 mg/Nm3 with reasonable control of oxygen; bed-overturn phenomenon occurs when lignite with ash content below 9% is burned, thus blending of other types of coals is needed.