Working principle of the injection tank (pulverized coal injection tank)

Working Principle of the Injection Tank (Pulverized Coal Injection Tank) The core function of the injection tank is to transform "solid pulverized coal" into a "transportable gas-solid two-phase flow." Its workflow revolves around four key stages: "coal loading - pressurization - fluidization - injection," as detailed below: 1. Coal Loading Stage: Pulverized coal from the grinding system is loaded into the tank via the upper feed valve (bell valve). The coal level is monitored by an internal level gauge, and the feed valve closes once the preset level is reached. 2. Pressurization Stage: Compressed air is introduced into the tank to raise the internal pressure to the required injection level (typically matching the blast furnace hot blast pressure). 3. Fluidization Stage: The fluidization device (fluidized bed + fluidization nozzle) is activated. Compressed air enters the tank through a porous plate or nozzle, causing the coal at the bottom to become "fluidized" (similar to a liquid flow state), eliminating bridging and accumulation of pulverized coal and ensuring uniform output. 4. Injection Stage: The discharge valve opens, and the fluidized coal is propelled by the tank's pressure into the self-mixer. There, it mixes with secondary compressed air before being transported through the coal pipeline to the lance and ultimately injected into the blast furnace tuyere. Key Design Highlight: By installing a "fluidization nozzle" in the conical lower head, the agitation effect of the airflow further optimizes coal fluidization. This design is suitable not only for new systems but also for retrofitting existing injection tanks, enhancing transport stability.