The metallurgical industry, including blast furnace ironmaking, open hearth furnace, converter, and electric furnace steelmaking, involves the transportation of a large amount of granular materials and meets certain process requirements during the transportation process. For example, the transportation and coal injection of blast furnace pulverized coal, the discharge of smoke slag in the blast furnace furnace, the transportation of lining materials such as dolomite powder, the transportation and carbon injection of carbon materials in the electric furnace foam slag submerged arc technology, the pneumatic sample delivery of samples in front of the furnace and the central laboratory, the injection system of cupola scrap iron, and the use of sending tanks to inject desulfurizer, dephosphorizing agent, desilication agent, etc. into the molten metal with nitrogen vapor and argon. Pneumatic conveying technology has been widely applied and developed in the metallurgical industry.

    The dense phase conveying coal injection system manufactured by Shandong Juheng Environmental Protection Equipment Co., Ltd. is divided into two parts: coal powder self-made and pneumatic coal injection. The coal powder is dried by a sorting machine, a vertical coal mill, and introduced with hot air. The coal powder and gas are separated by a special bag type powder collector. The entire coal powder manufacturing process is carried out under inert gas protection. The coal powder injected into the air inlet requires a large particle surface area to allow extremely fine particles to burn fully in the circulation zone. The system adopts a dense phase pneumatic conveying system to meet the above requirements, reduce conveying speed and energy consumption, minimize pipeline wear and reduce the amount of nitrogen used for conveying. The pneumatic coal powder injection system is generally located near the blast furnace, with dual sending tanks seated on an electronic scale. Coal powder is fed from the powder silo and weighed in the upper sending tank, while the lower sending tank is used for batching. There are several conveying pipelines from the sending tank to the blast furnace tuyere, each equipped with flow measurement and control devices. To save investment, a set of grinding and coal injection system can be used to supply two or more blast furnaces.

    The characteristics of this system are:

    1) The concentration ratio of the dense phase conveying material gas mixture is 50, which means that about 50kg of coal powder is conveyed per kilogram of nitrogen.

    2) The average conveying speed of coal powder in the pipeline is 1-3m/s, so there is less wear on the pipeline and distributor.

    3) Pipelines and distributors are suitable for coaxial spray gun coal injection, without the need to stop production, improving work efficiency.

    4) Control the flow rate of coal injection and accurately measure the flow rate on the tuyere branch pipe.