: Nowadays, Air separation units are used in several industries and the need for oxygen, nitrogen and argon increases day by day specially in steel industries .The best technique to go with is the cryogenic air separation which has the lowest energy cost per unit product. Even so this plant has a high energy usage and its’s efficiency is crucial for economical Steel making. The presented plant is oxygen production unit 1 in mobarake steel complex which hang yang corporations designed and built. Right now there is a huge gap between oxygen production rate of this plant is and it’s nominal production. On this ground the plant was simulated statically using aspen hysys process simulator then it was optimized for products to reach their nominal production rate. Then the plant was simulated dynamically and the respective controllers was tuned for optimum process function. Then a stability test was performed. Additionally specific power and oxygen recovery in steady state simulation was calculated for this plant. This study was based on a mission and these suggestions were proposed to Mobarakeh Steel Complex for Improvements in operating this unit. 1. To create the heat flow adequate for production in the right conditions, shift the molar flows of said streams to ones that was computed. 2. To ensure that this unit works correctly under these conditions, use tuned coefficients for controllers. 3. The operators of this unit utilize the data and information created by this simulation to get a better understanding of how this unit works so they could use it in order to improve their performance. 4. Ensure that compressors are in a good condition and check their efficiencies in constant periods of time so the specific power of the plant remain relatively low. Key words: Dynamic simulation, Cryogenics, Cryogenic air separation, Cryogenic distillation, Air separation unit, ASU, Oxygen plant
