Hydraulic Design of Thermally Coupled Columns and a DWC for NGL Fractionation Plants

Abstract

Combining a conventional demethanizer with thermally coupled deethanizer and propane-butane recovery columns or a three-product dividing wall column (DWC) provides a realistic opportunity for natural gas liquids (NGL) fractionation complexes as encountered in floating, as well as on-land natural gas liquefaction plants, to minimize energy requirements and reduce carbon dioxide emissions accordingly, in a cost-effective way. The present paper addresses and discusses hydraulic design aspects of these two thermal coupling arrangements, including the choice of the most appropriate column internals that largely depends on important design, construction, and operating considerations that differ for floating and on-land plants.

Equation-Oriented Optimization of a Distillation Column Considering Stage Hydraulics

“…The RSM is, however, not a rigorous model and can lead to errors especially for highly nonlinear and high-dimensional systems . The second approach is based on the sequential optimization method, − where decision variables are optimized sequentially based on process simulation, and when some variables are being optimized, the others are fixed. To consider the stage hydraulics of a distillation column in the design, a trial-and-error method is needed, and such method may make the solution process tedious and time-consuming.…”