The challenge
Freeze-out of heavy hydrocarbon contaminants in natural gas and build-up of formed solids in low-temperature heat exchangers can impede the efficient performance of Liquefied Natural Gas (LNG) production. Blockage remediation of these solids requires interruptions to LNG production trains due to system warmup and defrost or solvent injection. Limited research on freeze-out in industrial natural gas mixtures that contain multiple heavy hydrocarbon species hinders optimal methods for blockage avoidance and remediation.
The solution
This project used industrial natural gas samples provided by Freeport LNG (FLNG) to enhance the understanding of heavy hydrocarbons’ freeze-out behaviour. The experimental and simulation techniques developed by The University of Western Australia (UWA) were used to characterise heavy hydrocarbons in the FLNG samples, determine their precipitation and dissociation conditions and test temperature/solvents-based remediation methods.
The outcome
The research provided quantitative and qualitative phase equilibrium and remediation data for two industrial gas samples and one liquid sample. Measurements of solid formation and dissociation, Natural Gas Liquids (NGL) condensation and fluid composition via Gas Chromatography analysis were conducted. The results of the phase equilibrium measurements were compared with predictions made using the ThermoFAST software package and the measured compositions. Remediation methods using defrosting and/ solvent injection were performance tested at industrial pressures and temperatures.
The impact
This project generated new freeze-out and melting data for heavy hydrocarbons in industrial gas samples using state-of-the-art measurement technologies. The project enabled an industrial testing ground for unique measurement and simulation technologies. This research will contribute to the development of cost-effective and optimised remediation and operational processes to inform LNG operations.
Next steps
Data from this research project will be used to test UWA-developed software currently in operation in the LNG industry. The results will help maximise the production capability of LNG plants and support an efficient LNG industry both in Australia and globally.
Project researchers
- Dr Paul Stanwix
- Dr Brendan Graham
- Dr Peter Metaxas
- Dr Peter Falloon
Project status
Complete
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