SIMULATION ANALYSIS ON REGULATION METHODS FOR 99.9 OXYGEN PRODUCTION WITH AN METALLURGICAL ASU

摘要

In order to ensure the quality of electric steel production, the nitrogen concentration of the oxygen for convertor production must be controlled below 15ppm, which demands that the oxygen purity of the low pressure column of an air separation unit (ASU) is kept equal or above 99.9%. This paper developed a rate-based nonequilibrium model to simulate and optimize the process of 6# ASU, 60000Nm3/h, of Bao Steel Inc., China. The model is based on Peng-Robinson state equations which describe the gas-liquid equilibrium relationship among O2-Ar-N2. Based on the simulation of the 6# ASU under design and off-design conditions, three combined regulation methods are suggested to obtain 99.9% oxygen and maintain other products’ purity and output simultaneously. The following effects are achieved: obtaining 99.9% high-purity oxygen; keeping the purity of nitrogen above 99.99%; increasing the argon content in argon fraction to improve argon output.