Pulverized coal injection system of blast furnace and method for clearing out pulverized coal injecting pipe thereof

A pulverized coal injection system of a blast furnace and a method for clearing out a pulverized coal injecting pipe thereof are described. The pulverized coal injection system of the blast furnace includes a distributor, a plurality of pulverized coal injecting pipes, a plurality of Venturi tubes, a plurality of three-way shut-off valves and a filter. The pulverized coal injecting pipes respectively communicate with the distributor. Each pulverized coal injecting pipe is set with a first coal injecting valve, a second coal injecting valve, a purge valve and a first pressure relief valve. The Venturi tubes are and correspondingly disposed on the pulverized coal injecting pipes. The first coal injecting valve and the purge valve of each pulverized coal injecting pipe are located on an upstream of the Venturi tube, and the second coal injecting valve and the first pressure relief valve are located on a downstream of the Venturi tube. The three-way shut-off valves are disposed between the pulverized coal injecti