Improvement of the Deethanizing and Depropanizing Fractionation Steps in NGL Recovery Process Using Dividing Wall Column

In this work, our aim is to utilize a dividing wall column to improve the performance of the deethanizing and depropanizing fractionation steps in natural gas liquid processing. Starting from an initial conventional column sequence, the initial designs of the conventional dividing wall column and a top dividing wall column are obtained by maintaining the number of trays. In succession, they are optimized to reduce the energy consumption using factorial design. The results show that the conventional dividing wall column and the top dividing wall column can offer many benefits to the system, e.g., curbing the operating cost including refrigeration cost, and minimizing the reboiler and condenser duty. Furthermore, by using a dividing wall column, both the purity of ethane and its recovery rate are increased. The influence of utility prices on the operating cost saving of the conventional and the top dividing wall columns is also investigated. In addition, to further enhance the dividing wall column performance, heating is integrated on the top and an interreboiling system is installed at the bottom section of the dividing wall column.