Design and simulation of ethane recovery process in an extractive dividing wall column

Separation of CO2 from hydrocarbons in the natural gas is complicated due to the existence of an azeotrope between ethane and CO2 at the cryogenic temperatures. The key issues to break this azeotrope are high investment costs for the unit equipments and the associated high energy requirements. Accordingly, an innovative process based on the dividing-wall column (DWC) technology is designed using short-cut methods and relevant rigorous simulations. The energy demand and some environmental factors such as CO2 removal efficiency and CO2 emission reduction are studied for the conventional and DWC processes. It is found that the process including DWC is a better choice than the conventional one from economical and environmental point of views. Remarkably, this technology reduces the energy demand up to 51.6%.