(55b) Process Design and Development of Offshore NGL (Natural Gas Liquid) Recovery Processes

Sekwang Yoon¹, Jin-Kuk Kim¹, Chi-Kyun Park², Byung-Don Lee²

¹ Department of Chemical Engineering, Hanyang University, Wangsimni-ro 222,

Seongdong-gu, Seoul, 04763, Republic of Korea;

² Institute of Chemical & Environmental Process, Jeonjin Entech Co., Ltd, Gadal 1-Ro 38, Gangseo-Gu, Busan, 46729, Republic of Korea;

This work focuses on process design and development for the recovery of ethane (or propane) from natural gas liquids (NGL) to be applicable in the offshore environment. In this work, the NGL recovery is mainly made through the distillation at sub-ambient conditions, and low temperature condition is created by the use of a turbo-expander as well as J-T valves, which are interconnected with a demethanizer column.

Considerable efforts have been made in process design to improve energy efficiency of NGL recovery process without compromising product specifications. First, heat integration techniques have been applied to maximize heat recovery existed within the process. Second, attempts have been made to fully realize any potentials for power recovery. Third, column analysis has been carried out to identify any inefficient features in column design, and column is designed in an energy-efficient manner by introducing a few side-reboilers and selecting optimal flowrate and operating conditions for feed streams. Finally, optimization method has been rigorously applied to determine the most appropriate configurational features (i.e. interconnections between a column, heat exchangers and a turbo-expander.) as well as optimal operating conditions.

Offshore characteristics have been incorporated in the design of demethanizer column in this study, in which techno-economic impacts caused from ship motions are systematically considered. This work will also address control and operability issues, in the context of maintaining design feasibility of NGL recovery process, and achieving reliable and safe operation in industrial practices.

*This research was supported from the Technology Innovation

(10042424, Floating Production Platform Topside Systems and Equipment Development) funded By the Ministry of Trade, Industry & Energy (MI, Korea).

Korea Institute for Advancement of Technology(KIAT) through the Encouragement Program for The Industries of Economic Cooperation Region)(R0003996)