Modelling and optimization of ethane recovery process from natural gas via ZIF-8/water-glycol slurry with low energy consumption.

Effective recovery of ethane from natural gas plays an increasingly important role as ethane is a good raw material for ethylene production. The conventional cryogenic separation process (CryoPro) is energy intensive. Absorption-adsorption coupling separation process (SorbPro) using ZIF-8 slurry may be a more energy-efficient technique as its operating conditions are milder (i.e., 273.15 K, ∼1 MPa). This paper aims to conduct the process modelling and optimization of SorbPro for CH 4 /C 2 H 6 separation. The equilibrium stage method is used to model the mass transfer units (absorption-adsorption column, desorber, etc) and the key process operating parameters are optimized simultaneously by genetic algorithm. The results show that the ethane mole fraction can be enriched from 22 mol% in the feed gas to 90.04 mol%, the ethane recovery ratio reaches 90.34%, and the energy consumption per Nm3 ethane is 0.6792 kW h/Nm3, which is 25.6% lower than that of the CryoPro (0.9128 kW h/Nm3). It indicates that the SorbPro may be a more promising approach for recovering ethane from natural gas. • Novel process (SorbPro) using ZIF-8 slurry is developed for CH 4 /C 2 H 6 separation. • Process modelling and multi-parameter optimization for SorbPro is conducted. • Ethane recovery ratio of SorbPro is higher than 90%. • Unit energy consumption of SorbPro is 25.6% lower than that of cryogenic process. [ABSTRACT FROM AUTHOR]