The commonly available glycols and their uses are: 1. Ethylene glycol—High vapor equilibrium with gas so tend to lose to gas phase in contactor. Use as hydrate inhibitor where it can be recovered from gas by separation at temperatures below 50° F. 2. Diethylene glycol—High vapor pressure leads to high losses in contactor. Low decomposition… Read More »
Since there is a large difference between the boiling point of triethylene glycol (546°F) and water (212°F), the still column can be relatively short (10 to 12 ft of packing). The glycol liquid in the reboiler is heated to 340°F to 400°F to provide the heat necessary for the still column to operate. Higher temperatures… Read More »
On larger streams filter separators are used as inlet scrubbers to further reduce glycol contamination and thus increase the life of the glycol charge. Due to their cost, filter separators are not normally used on streams less than approximately 50 MMscfd. Often on these smaller units a section in the bottom of the contactor is… Read More »
Most glycol dehydration processes are continuous. That is, gas and glycol flow continuously through a vessel (the “contactor” or “absorber”) where they come in contact and the glycol absorbs the water. The glycol flows from the contactor to a “reboiler” (sometimes called “reconcentrator” or “regenerator”1) where the water is removed or “stripped” from the glycol… Read More »
By far the most common process for dehydrating natural gas is to contact the gas with a hygroscopic liquid such as one of the glycois. This is an absorption process, where the water vapor in the gas stream becomes dissolved in a relatively pure glycol liquid solvent stream. Glycol dehydration is relatively inexpensive, as the… Read More »