Process simulation and assessment of crude oil stabilization unit

Abstract

Crude oil is an unrefined petroleum composed of wide range of hydrocarbon up to n‐C40+. However, there are also a percentage of light hydrocarbon components present in the mixture. Therefore, to avoid their flashing for safe storage and transportation, the live crude needs to be stabilized beforehand. This paper aims to find the suitable operating conditions to stabilize an incoming live crude feed to maximum true vapor pressure (TVPs) of 12 psia (82.7 kPa) at Terengganu Crude Oil Terminal, Malaysia. The simulation of the process has been conducted by using Aspen HYSYS.

The obtained results illustrate that the simulation data are in good agreement with the plant data and in particular for the heavier hydrocarbons. For the lighter components, the simulation results overpredict the plant data, whereas for the heavier components, this trend is reversed. It was found that at the outlet temperature (85–90°C) of hot oil to crude heat exchanger (HX‐220X), the high‐pressure separator (V‐220 A/B) and the low‐pressure separator (V‐230 A/B) had operating pressures of (400–592 kPa) and (165–186 kPa), respectively, and the live crude was successfully stabilized to a TVP of less than 12 psia. The impact of main variables, that is, inlet feed properties, three‐phase separators operating pressure, and preheater train's performance on the product TVP, are also studied. Based on the scenarios analyzed, it can be concluded that the actual water volume (kbbl/day) has greater impact on the heat exchanger's duty; thus, incoming free water to Terengganu Crude Oil Terminal should be less than 19.5 kbbl/day (9.1 vol%) at the normal incoming crude oil flow rate of 195 (kbbl/day).