Ecoteg is a process that uses triethyleneglycol (TEG) to dehydrate gases rich in aromatic compounds (BTEX) where effluent control is critical. Its aromatics emission into the environment is negligible.
When TEG is used to dehydrate natural gas, it absorbs selectively not only water but also part of the BTEX that may be present. BTEX are released with all the outgoing streams of the regenerator. The vent gas off a still column is cooled in an overhead condenser (1) and condensed water and BTEX are separated in the overhead knockout drum (2). The
wet gas coming from (2) is reused as stripping gas and is fed to the bottom of the stripping tower by means of a blower (3).
The spent glycol is used to dry the gas recirculated to the stripping tower by means of a random-packed atmospheric absorber (4) and a glycol pump (5) to move the rich glycol from the bottom of the atmospheric absorber to the still tower.
The liquid BTEX are recovered as oil if an oil product is already present in the plant; otherwise, they are returned to dried gas by means of a pump (6) or recycled to presaturate the lean TEG.
Condensed water, before disposal, is stripped through a stripping tower (7) by means of combustion air.
Main advantages of the Ecoteg process are:
• Meet more stringent regulations for disposal without additional facilities
• Low operating cost
• Low gas dew point.
Operating conditions: Gas flowrates up to 15 milion scmd for each train, wet gas temperature up to 60°C and pressure up to 150 bar.
Economics: Ecoteg is an ecological and cost-effective dehydration process that does not require additional external facilities to meet regulations for effluents. This simplifies the first installation and/or additions to an existing plant. Savings in stripping gas helps the economics and may be a determinant when low gas dew points are required.
Licensor: SIIRTEC NIGI