Energy Analysis and Remixing Effect of Thermal Coupling Petlyuk Column for Natural Gas Liquid (NGL) Fractionation Train

In this work, a non-conventional distillation sequence with thermal coupling (Petlyuk Column) was presented as a technique to perform the separation of the NGL consist of ethane, propane, butane or other higher alkanes. The improvements were investigated through the energy analysis and remixing effect. From the result obtained, it was found that the Petlyuk arrangement consumes less amount of energy and able to reduce the remixing effects as compared to the conventional column sequencing. The Petlyuk arrangement saved about 44.49% and 12.83% in terms of cooling and heating duty, respectively. The overall annual energy saving shown by this arrangement is 39.22%. This arrangement proved to be able to prevent the remixing effect occurrence that contributes to thermal and separation inefficiency. The desired separation efficiency also obtained by this arrangement as all the product specifications are met. The ability in avoiding remixing effect by the Petlyuk column permits a significant reduction in CO2 emission with an average of 29.43 % of each equipment involved. Hence, it can be concluded that the Petlyuk arrangement model is a better alternative to be implemented in the NGL fractionation train.

Complex Systems of Distillation Columns Used in the Production of the Propylene Oxide

Complex systems of distillation columns were intensively studied within last decades and continue to show interest for researchers and for industrial application. The first designed complex distillation column with heat integration was the Petlyuk column and the development of complex systems of columns continued up to dividing wall columns (DWC) which are increasingly being used in industry. DWC are usually used to separate three products, components or fractions, from a multicomponent mixture. This study attempts to find the best fitting of complex systems of columns in the process of propylene oxide (PO) obtaining using the method of propylene chlorination and presents a proposed variant of separation which can lead to a reduced energy consumption. The fabrication of PO through this method lead to a multicomponent mixture which is separated in two main products: propylene oxide (PO) and heavier components containing as valuable compound 1,2 dichloropropane (DCP). Both products, PO and DCP, have important uses in the chemical industry. The study of complex schemes of columns used for PO separation was assessed by simulation using a simplified method based on Fenske � Underwood - Gilliland correlation (F.U.G.) [1]. The systems studied in this work include the following configurations of columns: column with prefractionator, column with partially coupled prefractionator, the Petlyuk column, the dividing wall column, column with side striper, column with side rectifier, the direct and the indirect sequence.