Liquefied petroleum gas recovery enhancement via retrofitting the refrigeration system of an existing natural gas liquid plant

Abstract

Nowadays, gas processing for natural gas liquids (NGLs) recovery is becoming of great interest. However, many of the present NGLs recovery units in operation do not give the desired revenue. This study focuses on the retrofitting of an existing NGLs plant constructed in Egypt for maximizing LPG product recovery due to its high economic value. Various alternatives have been suggested to maximize LPG recovery, while achieving the same cooling target and ethane recovery in terms of power consumption and additional capital cost. The economic study shows that replacing the existing pure propane refrigerant used to recover C 5 + (pentane and heavier) in the existing plant by a mixed refrigerant type is the best retrofitting technique. Furthermore, the exergy of the whole NGL unit was studied to evaluate the exergetic performance of all suggested upgrading methods. Regarding the upgraded plant, the butanes and propane recoveries were increased by 13% and 7%, respectively, with 15.95% increase in LPG overall recovery. In addition, the solutions of operational problems that may appear in the glycol injection system, propane refrigeration facilities, and de-ethanizer unit facilities when switching from single refrigerant to mixed refrigerant have been taken into consideration.

An Inclusive Review on the Assessment of Different Techniques for Natural Gas Liquid Recovery

“…A mixed refrigerant was used to save the cost and power consumption of liquified petroleum gas. Retrofitting the existing plant with a mixed refrigerant unit would require higher capital costs but lower operating costs compared to a turboexpander [24].…”

Techno Commercial Analysis of Liquefied Petroleum Gas Recovery From Natural Gas Using Aspen HYSYS

“…The exergy destruction in the LPG production process happens at the fractionation columns (Saadi et al, 2019). The exergy analysis carried out in a retrofitted refrigeration system, for the recovery of LPG from the natural gas plant located in Egypt, indicated an increase in the overall LPG recovery by 15.95% (Shehata et al, 2019). Simulations of the natural gas processing plant have been reported in good detail to provide insight into the containment removal with some cost analysis of different turbo expander systems (Mehrpooya et al, 2006;Roy and Amin, 2012;Çinar et al, 2016).…”