Effects of Tilt and Motion on LNG and GTL Process Equipment for Floating Production

Types of process equipment used in LNG and GIL production which are more likely to be affected by marine tilt and motion on proposed floating production systems are first reviewed. GTL production processes will inevitably involve contacting columns for feed gas purification, cryogenic air separation in processes requiring oxygen and for product separation. Ongoing research into the effects of tilt and motion on liquid distribution in packed contacting columns is described. Means of quantifying the extent of maldistribution and its effect on separation performance are considered. The resistances of different types of packing to tilt effects are compared. In large scale LNG processes, the largest and most expensive item of process equipment is generally the coil wound heat exchanger(s), where evaporating liquid flows over the outside of a complex array of tubes. Research into the effects of tilt and motion on liquid flow and distribution over the tubes of such exchangers is described. The experimental studies are done on a relatively small scale but utilise full-scale components to give more directly applicable data. As in the contacting column research, the effects of liquid surface tension on liquid flow are being studied in view of the low surface tension of the cryogenic liquids involved in the full- scale applications. Surface tension and the presence of tube spacers are shown to influence liquid distribution in both the normal static orientation and under tilt conditions.