Comparative study on simulations of Linde double column and Linde Frankl for the production of liquid nitrogen and liquid oxygen using DWSIM

Two of the most important cryogenic fluids are liquid nitrogen (LN2) and liquid oxygen (LOX), which have many applications in medicine, aircraft, food preservation, and metal production. Industries used various production techniques to fulfill the massive demand for these liquids. The two most well-known of these are the Linde-Frankl (LF) and Linde double column (LD) processes. The LD and LF procedures were replicated in an open-source and user-friendly program called DWSIM to generate LN2 and LOX, respectively, and then compared. Since the Peng-Robinson equation of state well predicts the thermodynamic behaviour of actual gases and can successfully manage the Vapour-Liquid Equilibrium (VLE) 26 computations, and it was used as a thermodynamic model in both simulations. Compared to 27 the LF process, the LD process demonstrated higher product purity and greater efficiency thorough simulation study. The distillation columns used in the LD process were the subject of 29 an optimization study. The results showed that the primary column had 20 stages and a reflux ratio of 1.5, while the secondary column had stages and a reflux ratio of 15. This allowed for the production of extremely pure products (Liquid Nitrogen up to 99.99% and Liquid Oxygen up to 99.9%) while minimizing wastage (purge stream flow rate = 129.956 Kmol/hr).