Conceptual Design of NGL (Natural Gas Liquids) Recovery Units for New Process Development

NGL (Natural Gas Liquids) recovery processes are widely applied in natural gas processing as a realistic and cost-effective measure for gas monetization. Turbo-expander process is usually selected for NGL recovery plants because of higher energy efficiency and better process compactness, compared to other technologies.

This presentation is to introduce a new NGL process using a turbo-expander, which has been evolved from conventional flowsheets. New configuration has been achieved through structural changes in the flowsheet, for example, different stream splitting or merging, and different stream population for heat exchangers. Several design options for changing process configurations are screened and their techno-economic impacts are assessed in an integrated manner. Optimization is also carried out to maximize the benefit of any structural changes considered, in which key operating parameters are simultaneously determined. Optimization framework used in this study is to link a stochastic GA solver with a process simulator, with which system interactions affecting energy recovery and hydrocarbon recovery in the NGL process are effectively dealt with.

Cost analysis shows economic benefit of the proposed new NGL process, compared to conventional turbo-expander processes. It is also found that operating flexibility can be enhanced by accommodating different operating modes for the new NGL process.

Acknowledgement

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).