Medium-speed coal-mill direct-firing pulverizing combustion system for burning high-moisture lignite

The invention provides a medium-speed coal-mill direct-firing pulverizing combustion system for burning high-moisture lignite, which can dry and burn high-moisture lignite. The system consists of a medium-speed coal mill, a pulverized coal concentrator and a burner. The system can adopt a primary air rate of over 40 percent to meet the drying capability of the system, and separates a primary air-powder current to be a dense-phase current and a thin-phase current through the pulverized coal concentrator on an outlet of the coal mill, wherein the dense-phase current enters a pulverized coal nozzle as primary air, and the remaining part of the current enters a furnace as secondary air, OFA or SOFA. The system has a good solution to the problem of drying high-moisture lignite, helps to organize a combustion power field in the furnace, and solves the problems that medium-speed coal-mill direct-firing pulverizing systems for burning high-moisture lignite are insufficient in drying capability, unbalanced in the ratio of primary air to secondary air, as well as momentum, not ideal in the combustion power field in the furnace, and the like.