Nowadays, gas processing for NGLs (natural gas liquids) and LPG (liquefied petroleum gas) recovery is becoming of great interest due to the increase in market demand as well as the higher sale prices of these products. However, many of the present NGL and LPG recovery units in operation don't give the desired revenue. This study focuses on the retrofitting of El-Wastani petroleum company (WASCO) which is one of the most important NGL/LPG recovery units constructed in Egypt. The performance of this unit has been simulated and improved by modifying different factors. The most important studied factors are capacity, feed type (composition), and recovery efficiency.  The results showed that the lean gas feed (low butanes) is the worst type which gives the same LPG recovery efficiency but with low productivity and higher energy requirements compared with rich feed (more butane). Hence, for confirming the plant improvements at any feed composition, the effect of gas feed capacity on the plant profitability will be based on lean gas feed. According to the simulation and optimization results, the growing economic opportunities offered mainly when the gas feed capacity increases by 25%. In this case, the pay-back periods of the added equipment were characterized by high or reasonable investment strength, which means that all modification costs will be recovered within short or acceptable periods. Both new and plants in operation will benefit from the modifications and performance improvements discussed in this study. This work can be taken as guidelines to aid operating companies improve their profits resulted from existent plants retrofitting.