The growing need to find a suitable fuel that is both environmentally safe and low in cost around the world has led to the discovery of many different types of fuels that achieve this goal. As a clean and cheap fuel, LPG is one of the choices to achieve these objectives. In Iraq, the demand for LPG fuel increased rapidly, emphasizing the need to find a way to increase LPG production while keeping costs low. This is a main objective of unit optimization (increasing profit and decreasing cost). The goal of this study was to simulate the LPG unit in the largest refinery in Iraq while keeping costs low and increasing the recovery percentage using one of the important optimization methods. The old and complex design of the LPG recovery unit made it difficult to simulate and optimize it. Aspen hysys V11 was a simulation program which was used to simulate this unit. It has an optimizer which consists of many optimization methods used to optimize parameters of the model. To begin with, validate the model and compare it to the design in order to optimize it. The first part of this unit was the sweetening part, and the second was the LPG recovery part. The simulation of the sweetening part gave us good results for this part of the research. The LPG recovery part was not easy to simulate, but in the end, the results of the simulation were good. We chose the sequential quadratic programming algorithm by hyprotech SQP, which is one of the most famous methods used for optimization, which increased the recovery percentage and reduced the consumed energy in this process. This will lead to an increase in profit and reduce the cost that was the objective of this study. This option gave us an increase in production of LPG of 1 ton per hour and included the specification of storage and selling.
