Advanced LNG Technology

Transporting natural gas from production to points of consumption requires large pipeline networks. Thus, only overland or somewhat shorter undersea routes can be considered. Liquefaction of natural gas serves to overcome these obstacles, and permits transport over larger distances allowing for a more diverse application of LNG. The principal reason for transporting natural gas in liquid state is a 600-fold reduction in volume that occurs with the vapor-to-liquid phase change. Natural gas can be liquefied only under certain conditions after purification. The gas purification is needed to remove impurities such as water, carbon dioxide, and hydrogen sulfide. Light inert gases such as argon and helium are also removed, along with heavy hydrocarbons including propane, butane, and so on. Almost all natural gases contain some components which solidify when natural gas is transformed to LNG at atmospheric pressure. Some components must be removed to meet the LNG specification. It is essential to remove these impurities down to a concentration where they do not present a problem. A technology has been developed at Curtin University to sweeten gas using the Curtin Contaminant Tolerant Process (CCTP). The technology results in a compact module, commercially known as the LNG Micro Cell, which is portable and can be easily accommodated on production platforms; it is energy efficient and can process a wide variation in feed gas composition. Up to 70% carbon dioxide as a contaminant of the natural gas volume, has been successfully removed down to less than 200 PPM during laboratory trials. This paper describes the CCTP and also investigates the potential to use the module for gas sweetening post-pipeline, as a pipeline precursor to establish reticulated gas systems in regional and remote communities.