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Technology qualification of flashing liquid expanders for the ConocoPhillips optimized cascade® LNG process.

Numéro : 77

Auteurs : RYDLAND J., POLLOCK A., BISSON S.

Résumé

Flashing Liquid Expanders (FLEs) present a promising avenue for enhancing energy efficiency, increasing capacity and reducing carbon emissions in LNG liquefaction processes by recovering energy from high-pressure LNG streams. This approach has been well researched for the High Stage and Intermediate Stage J-T valve locations in the ConocoPhillips Optimized Cascade process, where multiple flashing stages in the methane refrigeration loop create ideal conditions for FLE integration.
Due to the high vapor mass fractions at outlet conditions of the proposed locations, existing radial flow turbine designs are not suited to the application, hence the need to develop a cryogenic impulse turbine or FLE. Despite their potential, the adoption of FLEs has been limited due to concerns over technology maturity, operational reliability, and integration challenges within existing LNG facilities.
This paper presents the results of a structured Technology Qualification (TQ) study commissioned to assess the readiness, applicability, and risks of deploying a Flashing Liquid Expander in the High Stage Flash Optimized Cascade context. The assessment combined Technology and Manufacturing Readiness Level assessments with a detailed Failure Modes and Effects Analysis (FMEA), from a single vendor selected by the operating plant. The goal was to systematically identify and mitigate technical risks and establish a clear implementation pathway for a novel axial impulse-style expander capable of handling two-phase flow with a significant vapor fraction.
Key findings highlight that while the mechanical principles of the FLE draw on proven cryogenic pump and turbine experience, critical elements such as rotordynamic behavior under transient loads, cryogenic generator cooling (including parasitic losses), nozzle and part load performance, require further validation. The Optimized Cascade process imposes additional integration demands, such as fast load transfer to backup JT-valves and predictable behavior under trip conditions, which were explicitly addressed in the qualification scope. The TQ process facilitated the development of targeted mitigation strategies, including design optimizations, enhanced testing protocols, and operational safeguards, to address identified risks.
The study shows that FLE technology offers clear gains – higher LNG output, reduced emissions, and lower fuel use – within identifiable and manageable risks. Using a rigorous TQ framework, these risks are systematically addressed and mitigated to acceptable levels, enabling confident
integration into the OCP process. For new LNG developments, where gas supply is unconstrained, FLE adoption represents an opportunity to enhance performance and efficiency at the same time; for existing facilities, it remains a compelling option wherever process conditions allow integration
without major upstream limitations.

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Détails

  • Titre original : Technology qualification of flashing liquid expanders for the ConocoPhillips optimized cascade® LNG process.
  • Identifiant de la fiche : 30034690
  • Langues : Anglais
  • Sujet : Technologie
  • Source : 21st International Conference & Exhibition on Liquefied Natural Gas (LNG2026)
  • Date d'édition : 05/02/2026

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