Avoiding sulphur compound freeze-out in liquefied natural gas production (22.RP1.0115)

During the production of liquefied natural gas (LNG), impurities within the gas stream can freeze-out and block the cryogenic heat exchangers that are critical to liquefaction. Although sulphur compounds are ubiquitous contaminants of natural gas, there is very little existing experimental data that can be used to accurately characterise the freeze-out of these compounds. This has subsequently led to significant uncertainties in sulphur-compound freeze-out predictions within the engineering models that underly LNG plant design. Accurate predictive capabilities are however critical since even small changes in operating conditions enabled by enhanced confidence in predicted freeze-out conditions can have strong positive outcomes for an LNG plant’s energy efficiency and operational costs. To address this industrial knowledge gap, this project will generate new freeze-out and solid-phase-stability data for LNG-relevant sulphur compounds at industrially pertinent concentrations. Achieved using a state-of-the-art, high pressure, cryogenic, optical apparatus the project’s experimental results will then be used to develop new, reliable engineering models for predicting the solubility of sulphur compounds in methane. The experimentally validated, tuned models will be implemented within the free software packages ThermoFAST and ThermoFAST Weballowing for widespread use by gas process and LNG production engineers, thereby enabling the design of higher efficiency LNG plants.

Partners: GPA Midstream Association, The University of Western Australia

Researchers: Dr Paul Stanwix, Dr Peter Falloon. Dr Brendan Graham, Dr Peter Metaxas

Duration: 3 years