The injection system consists of different types of injection tank groups and corresponding bell valves, fluidization devices, etc. Pulverized coal injection is usually filled with compressed air in the injection tank group, and secondary compressed air is introduced into the self-mixer to inject pulverized coal into the blast furnace tuyere through pipes and spray guns. Among them, the injection tank group can be arranged in parallel, with coal loading and coal injection taking place alternately; it can also be arranged in an overlapping arrangement, where the bottom tank is only used as an injection tank, and coal loading is completed through the upper tank and its pressure equalizing device.