Study of possible options for technological schemes of gas fractionation plants for a wide fraction of light hydrocarbons

Abstract

Analysis of the component composition of the ethane-propane fraction obtained from the wide fraction of light hydrocarbons (NGL) at operating gas fractionation plants shows that due to the insufficiently clear separation of light hydrocarbons С1÷С3, a high propane content is observed in the ethane-propane fraction (EPF). SPE is used in the pyrolysis plant, where ethylene is obtained as the target intermediate, therefore, under industrial conditions, it is necessary to ensure the maximum possible extraction of propane from the SPE composition. In the technological scheme of operating plants, SME is obtained using a fractionating absorber or a distillation column. In both versions, the SME is taken from the top of the apparatus, and the bottom product containing C3+ hydrocarbons is fed for further fractionation. In order to analyze the operation of gas fractionation plants in the Honeywell UniSim Design software environment, a plant model was developed. A computational experiment using various industrial values of the hydrocarbon content in NGL showed that in order to achieve the maximum possible extraction of propane from the PSP, it is necessary to involve all the propane in the PSP obtained on the fractionating absorber (or distillation column) so that only the C4+ hydrocarbon fraction is in the bottom product of the apparatus for further separation. The ESP obtained in this way is sent to an additional distillation column, which provides a clear separation into ethane (distillate of the column) and propane (bottom product of the column) fractions, while in the obtained fractions concentration indicators are achieved that improve the corresponding indicators of standards according to TU 0272-022- 00151638-99. The calculated regime parameters and fractional compositions of technological flows of apparatuses are given, the modified scheme of the installation is described. The developed models can be used to optimize the operating modes of industrial devices and design new installations, as well as to train technologists in the methods of qualified process management.