Process simulation and evaluation of NH3/CO2 separation in melamine tail gas using deep eutectic solvent

Melamine tail gas contains large amounts of NH 3 and CO 2 . Its NH 3 uptake is important for improvement of gas quality and resource recycling. The conventional solvent absorption and urea cogeneration methods suffer from the high energy consumption. Due to the advantages of low price, good renewability and low toxicity for deep eutectic solvents (DESs), a new absorption and separation process using NH 4 SCN: glycerol (2:3) DES was proposed and simulated using Aspen Plus V12™ in present contribution. Based on estimation method and experimental data, physical parameters such as density, viscosity, heat capacity, and thermal conductivity of DES were obtained. Two new process technologies, the basic DES-based process (DES-0) and the enhanced DES-based (DES-EN), were evaluated from energy and cost effectiveness. The conventional water scrubbing process (WS), DES-0, and DES-EN were systematically evaluated from process sensitivity analysis. Results demonstrated that the NH 3 concentration of the products reached 99.6 % (mass fraction) for all three methods. Compared with the WS method, the cooling water usage of DES-0 was reduced by 89.16 % and the equipment cost dropped by 86.46 %. The total separation cost of the DES-0 process was 158.56 $·t −1 NH 3 , 79.43 % lower than that of the WS process. • Two new processes of NH 3 /CO 2 separation in melamine tail gas using NH 4 SCN: glycerol (2:3) DES were evaluated. • Reliable thermodynamics models were built and verified with experimental data. • Conventional water scrubbing versus DES-based processes were compared. • TSC of DES-EN process can be reduced by 79.43 % than WS process.