Natural Gas must often be dried before it can be distributed to its end users. The drying is necessary to prevent hydrate formation and liquid water deposition in the pipelines and/or condensation in the compressors; all of which would either cause damage or poor performance of the equipment. This drying is often accomplished by dehydration utilizing Tri-ethylene Glycol (TEG) contactors, which are very effective but introduce a TEG residue carryover into the Natural Gas. The drying process has a high cost associated with it, therefore it is important to dry the gas but not spend excessive resources to over dry it. Thus it becomes important to perform moisture content measurements on the Natural Gas after it has passed thought the dehydration equipment. Not dry enough and there may be failures – while too dry and there is a waste of resources.
When Liquefied Natural Gas (LNG) is “re-gassed” for pipeline transmission/distribution,
it is passed through heat exchangers which are prone to leakage thus can introduce
unwanted moisture into the very dry gas. Therefore it is important to monitor the
moisture content after the heat exchangers for leak detection and quality control.
The custody transfer of Natural Gas often requires monitoring of the moisture content of
the gas as a quality control.
The gas must be sufficiently dry as not to form ice, after cooling from pressure drops.