Diseño y simulación de una torre despropanizadora para el procesamientode gas natural en plantas de fraccionamiento

Abstract

The objective of this technical project was to comprehensively address the design and simulation of a depropanizer tower for natural gas processing in fractionation plants. The depropanization process was designed to treat a multicomponent feed of 35000 barrels per day of natural gas liquids. The design of the fractionation column was carried out using abbreviated calculation methods for multicomponent distillation, matter and energy balances, and iterative bubble point/dew point calculations. These engineering calculations allowed determining the operating conditions and column requirements necessary to achieve the desired separation. The design of the depropanizer tower was complemented by simulating the process in DWSIM, using both the simplified model and the rigorous model for distillation columns. The simulation was also used to perform a sensitivity analysis and study the effect of the feed thermal condition on the column performance. The results of the developed design found that the depropanizer tower requires a total of 31 plates operating at a reflux ratio of 2,07 to obtain propane with 97% purity in the distillate. Both manual calculations and process simulation produced similar results for the column design, with a maximum of 6% difference between the values obtained. The sensitivity analysis indicated that the heat required in the reboiler decreases as the steam present in the feed increases. In conclusion, it was possible to design a plate column to produce practically pure propane by multicomponent distillation of liquids from natural gas. Further study of the depropanization process is recommended through the development of additional sensitivity analyses, pilot scale tests, environmental impact assessments and scalability studies.