Specifications, glycol dehydration unit

The treated gas leaving the M D E A unit will require downstream dehydration since the pipeline gas specifications require a minimum water dew point. This is best achieved with a conventional TEG glycol dehydration unit, as the gas is very lean without condensable hydrocarbons. 

Finally, it should be noted that in the operation of a glycol dehydration unit, the desired outcome is to meet the water content specification for the outlet gas, e.g. 7 lbs H20/MMSCF (112 kg/10 Sm ). When using the graphs in this paper, different operating points (temperature, pressure and circulation ratio) will produce different outlet water eontents. Make sure that the operating points you are using to estimate BTEX absorption ean also meet the water specification. 

An alert on hydrocarbon emissions from glycol dehydration units issued by 77te American Petroleum Institute, in connection with their Specification for Glycol-Type Gas Dehydration Units (1990), contains a mass balance for a 10 MMscfd TEG unit operating at 800 psia and 130°F with a feed gas containing 100 ppm benzene. The study indicates that 10% (3 tons per year) of the benzene is absorbed and discharged in the regenerator vapor stream. In this... 

Typically, the separator is a vertical cylindrical vessel equipped with vanes and/or mesh to remove fine droplets of liquid from the gas. Tables for estimating the required diameter of separators for various gas flow rates and conditions are given in several publications, including The API Specification for Glycol Type Gas Dehydration Units (1990) and a paper by Pearce and Si vails (1993). The tables are based on the Souders-Brown correlation, which is quite simple to use directly, i.e.. 

American Petroleum Institute (API), 1990, Specifications for Glycol-Type Gas Dehydration Units" API Spec. 12 GDU, First Edition, Dec. 15, 1990. 

API Specification 12GDU, Specification for Glycol-T5rpe Gas Dehydration Units, 1st ed., December 15, 1990. 

Membrane units have a smaller plot space requirement and weigh less than most other process units, These factors, as applied to an offshore installation, were evaluated by Cooley (1990). A comparison was made between an aniine/glycol unit and a membrane unit designed to treat 96 MMscfd of natural gas at 1,000 psig. The systems were designed to reduce the CO content of the gas from 15.8 to <2% and dehydrate the gas to North Sea specifications. The results of the comparison are presented in Table 15 16. 

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