Using Dividing Wall Columns (DWC) in LNG Production: deviding wall column, double dividing wall column, prefractionator arrangement, Petlyuk column, NGL recovery, distillation

Abstract

The Dividing Wall Columns (DWC) distillation has attracted growing interest for fractionation of multicomponent mixture due to reduction of energy consumption, auxiliary equipment and space within fractionation process. Recent developments of the process show considerable energy saving, up to 30%-40%, compared to conventional fractionation schemes. The objective of this thesis is to introduce DWC configurations, governing equations and applications in LNG and gas processing as well as explanation of different methods and processes for industrial production of LNG and LPG. In addition, a consistent and fair comparison between conventional fractionation schemes and two types of DWC i.e. Kaibel and multi-partitioned (Sergant DWC) with respect to energy consumption and other parameters have been conducted. The evaluation was done using Aspen HYSYS simulation program version 7.3 for a typical natural gas feed specification. The study indicates beneficial DWC utilization in terms of energy consumption, auxiliary equipment and duties of condensers and reboilers. Simulation results show energy consumption in LPG extraction process using Kaibel DWC about 31% less than conventional fractionation scheme while multi-partitioned configuration of DWC is even better and it can save energy up to 37%.