Evaluation of MEG as alternative ofTEG for higher performance of natural gas dehydration

Glycol dehydration is a widely used method for the removal of water from natural
gas, using glycol as a solvent to absorb water from the gas stream. The presence of
water will promote the occurrence of corrosion and hydrate formation along the gas
pipelines. Tri-Ethylene Glycol (TEG) is commonly used as the solvent for glycol
dehydration. The main environmental concern of this TEG process is the emission of
benzene, toluene, ethylbenzene and xylene (BTEX) compounds to the atmosphere.
This study will be using Mono-Ethylene Glycol (MEG) as the solvent, where the
objectives are to compare the performance of MEG with TEG, mainly in reducing
the amount of BTEX emissions. The scopes of this study are the simulation of three
glycol dehydration technologies which are basic, Stahl ,and Drizo. MEG will be used
as the dehydrating agent in this study, and optimization of operating conditions is
done in order to have an optimized process operation of MEG.
The data and results are obtained by process modeling using the Aspen Hysys
simulation package. Performance of MEG is evaluated and compared with TEG.
Based on our analysis we can see that the usage of MEG significantly reduced the
amount of BTEX emissions without any need of equipment addition for the same
glycol dehydration technology, where the amount of emission is almost zero.
However, usage of MEG will result in higher amount of glycol losses. If MEG is
used, it must be determined if the cost of glycol replacement is less than the cost of
treating the BTEX emissions.