Thursday, June 6, 2013

The Logic Behind The Magic." Glycol Dehydration System 5"

TEG Regeneration Package




TEG Reflux Condenser

TEG Reflux Condenser is located at the top of the TEG Still column and used to maintain the temperature of the steam leaving for condenser. Rich glycol flowing through the TEG reflux condenser coils is warmed to 49.48 degC by steam and glycol vapour present in the steam is condensed on the shell side.
  
Cold TEG Exchanger

Rich glycol from the TEG reflux condenser is sent to a hairpin type 210.1 kW, Cold TEG exchanger where it is warmed by counter flow of lean glycol to approximate 87.78 degC before entering the TEG flash drum for most effective separation and removel of dissolved gas and liquid hydrocarbons.

TEG Flash Drum

In the TEG Flash drum the dissolved hydrocarbons are separated from the glycol. Separated gas is passed through a mesh pad to remove entrained liquid before leaving the TEG flash drum. The  the gas is sent to LP flare header under pressure control. A fuel blanketing is provided to suplement the gas flow, if necessary to maintain vessel pressure.

TEG Catridge Type Fine filters

Rich glycol from the TEG flash drum flows into the TEG Cartridge type fine filter. Solid particles are removed from the glycol by the cartridge filter. If these particles are not removed. They may damage the liquid trims, plug the TEG still column packing and cause foaming  in the TEG contactor.

TEG Activated Carbon filter

Rich glycol from TEG Cartridge type fine filter is sent to the activated carbon filter, sized for 5 m3/hr flow. The activaed carbon adsorbs the dissolved hydrocarbons contained in the rich glycol. This can be very benificial in redicing the heat load on the reboiler, and reduce glycol carryover and vaporization losses in the reflux column due to foaming of the hydrocarbons. The rich glycol flows into 485 kW hairpin type Hot Lean/Rich TEG exchanger.

Hot TEG Exchanger

The filtered rich glycol from TEG Activated Carbon Filter is preheated in the 485 kW hairpin type Hot TEG exchanger through heat transfer with the outpoing lean glycol from the stripping gas column. The hot rich glycol the flows across the TEG flash drum level control valve into the TEG column. The level control valve is located downstream of the hot TEG exchnger in order to maintain back pressure on the exchanger and minimize vapour regeneration within the exchanger.

Stripping Gas Column

The Stripping gas column is packed with 0.194 m3 random packing over a height of 1500 mm. The normal case condition should not require stripping gas to reduce the water content. The stripping gas would be used in emergency only.  The stripping gas is provided to reduce the water content of the regenerated glycol by counter current contact with hot fuel gas  flowing upward through the stripping gas column. The stripping gas also reduces the partial pressure of the vapor in the TEG reboiler. Regenerated glycol flows from the bottom of the stripping gas column by gravity into the hairpin type hot lean/rich TEG exchanger where it is cooled to approximately 124.8 degC and then goes into the other hairpin type cold lean/rich TEG exchanger where it is further cooled to approximately 85.55 degC 

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