Hydrodynamics Modeling of Distillation Tray of MLNG Depropanizer Column

Hydrodynamics modelling in a distillation column covers three important aspects;
namely operating region, pressure drop across plate and plate efficiencies. All these
three are inter-related. Operating region provide the limit for the vapour and liquid flow
allowable for the column operation. Meanwhile, pressure drop across plate allows for
determination of plate pressure drop which affects the overall pressure drop for the
column. Lastly, plate efficiencies allows for prediction of separation efficiencies which
affects the overall separation performance. It also reflects the ability of the contactors to
perform the required separation. Distillation is a process of physically separating a
mixture into two or more products that have different boiling points, by preferentially
boiling the more volatile components out of the mixture
As for this project, the main focus is in producing the feasible operating region for
depropanizer column (C-1503) ofMLNG plant. The quantified region can also be used
to identify the type of physical constraint that upsetting the column operation. In
MLNG plant, Bintulu, hydrodynamics detail research especially the downcomer section,
Shell Calming Section tray is enquired to ensure a smooth operation throughout without
disconcerting the column performance. Besides that, a consistent demand of pure
propane from customer added the need to meet the product specification through an
optimum working region.
Hydrodynamics studies consists of calculating the maximum and minimum operating
region for tray column by considering four significant upset contributions phenomena,
i.e., entrainment flooding, downcomer backup, weeping and sealing. The ultimate
research is to produce a visual presentation of the operating regime with respect to liquid
and vapor loads. The project started off with a good literature understanding of the
hydraulic behaviour of distillation column. Then, it proceeded with identification ofcorrelation step, where justification and assumptions were made before any further
engineering calculation. Software aid-tool such as HYSYS, MATLAB and Microsoft
Excel were used to assist in getting primary raw input data and also to solve numbers of
equations. The result of the simulation and calculation for depropanizer steady state
shows that the developed model can be concluded as realistic and can represent
accurately a feasible yet an optimum region of the column.