Oxygen Lance System

The Oxygen Lance System is an essential component of the Integrated Blast Furnace and Basic Oxygen Furnace Steelmaking System. It consists of a water-cooled lance that injects high-pressure, high-purity oxygen into the molten iron bath within the basic oxygen furnace (BOF). This injection facilitates the oxidation of carbon, silicon, manganese, and phosphorus impurities, enabling precise control over the steelmaking process, temperature regulation, and slag formation. The system is designed for integration into BOF vessels, with the lance being lowered and raised vertically to control the oxygen injection point. Key parameters include a rated oxygen flow of 1000–5000 Nm³/h, operating pressure of 1.0–1.6 MPa, lance length of 15–25 m, lance diameter of 150–300 mm, cooling water flow of 100–300 m³/h, cooling water pressure of 0.6–1.0 MPa, maximum operating temperature of 1600–1700 °C, lance material of 20G–25G (GB 5310), nozzle material of CuCrZr (ASTM B187), weight of 2–8 t, lance stroke of 10–20 m, and oxygen purity of 99.5–99.9% (ISO 20480). These values are reference ranges and must be verified for the specific model and application with the legal manufacturer or supplier. The system's performance directly affects decarburization rate, refining time, and overall steel quality. Proper selection requires consideration of furnace geometry, bath depth, and oxygen supply infrastructure. The lance tip, made of copper alloy, must withstand extreme temperatures, while the carbon steel body provides structural integrity. Stainless steel internal piping ensures corrosion resistance. The system interfaces with the BOF control system for precise lance height and oxygen flow regulation. Maintenance signals include reduced oxygen flow, increased cooling water temperature, or abnormal vibration, indicating potential nozzle wear or lance deformation. Failure boundaries include exceeding maximum operating temperature or insufficient cooling water pressure, which can lead to lance failure and process disruption. Verification questions for procurement include confirming the lance length matches the furnace height, ensuring the oxygen purity meets the required standard, and validating the cooling water flow and pressure for the specific operating conditions.

The system operates by lowering a water-cooled lance into the BOF vessel. High-pressure oxygen (typically 8-12 bar) is forced through nozzles at the lance tip, creating supersonic jets that penetrate the molten bath. This creates intense turbulence, promoting rapid oxidation reactions (decarburization) and efficient heat transfer. The lance's height and oxygen flow rate are precisely controlled to optimize the refining process.