As the special design of the down-fired boiler in extending particle’s residence timein the furnace, it is widely used in the combustion of anthracite. However, a lot ofproblems exist in the process of power generation, such as low combustion stability andeconomy, high NO_xemission, serious slagging. This work is based on the numericalsimulation and tests to study the effects of combustion retrofit and optimization oncombustion stability, economy, and NO_xemission etc. in a300MW down-fired boilerwith split ...