RE-GENERATOR

Re-Generator(Method to Recovered Glycol from Water-Glycol Mixture)

The re-generator is a combination of glycol re-boiler and the still column. They work together to regenerate rich glycol. Making it lean glycol and ready to use in the contactor column. 
The re-boilers supply heat to separate glycol and water by simple distillation. Glycol is heated to a temperature between 
380℉ to 400℉
(193℃ to 204℃)
to removing up water vapor to regenerate the glycol to 98.5% to 90%. The temperature of TEG should not exceed 400℉ (204℃) because TEG will began to breakdown at higher temperature. Re-boilers can be direct fire (Nandpur Field) or heated by steam or hot oil.
Direct Fire Re-Boiler
Direct Fired Re-boiler type containing a removable fire box and fire tube is normally used and over flow weir maintains the glycol level in the re-boiler excess glycol spills over the weir and flows downward into the surge tank by gravity by passing through Glycol-Glycol Heat Exchanger.
When the glycol level is low in the surge tank fresh glycol is enter to the re-boilers it ran be dried before going into surge tank. 
Still Column
The still column or stripper located just above the re-boiler is where the actual distillation of water from glycol takes place. Still column are normally packed column and have thin condensers or reflux coil in the top. These condensers or reflux coil cool water vapors leaving the column and requiring drain glycol. The amount of glycol lost with the water vapor leaving the still column is controlled by the temperature of the water vapor. Now this called the still overhead temperature should be said that boiling point of pure water.
Normally the pressure will be atmospheric 14.7psia at sea level and the temperature will be 212℉(100℃). System operating above sea level, where require low temperature due to lower pressure, systems with back pressure will require higher temperature.

Still Over Head Temperature
If the still overhead temperature is above the boiling of pure water. 
Glycol carryover is the result and losses will be higher than normal. 
If the still overhead temperature below the boiling point of pour water. 
Too much water will condense back into the glycol. 
This will cause both re-boiler heat requirements and fuel usage to increase. When the glycol flow rate exceeds maximum design limits a condensation know as column flooding occurs. 
Column Flooding
Column flooding is when the still column fill with liquid. 
Cause of Column Flooding
  • This occurs when the glycol being feed to the still column and has a high concentration of light hydrocarbons. These hydrocarbons will distill out of the glycol and condensing the upper portion of the column.
 Column flooding does not alloy properly glycol water separation. Rich glycol can be lost to the vent line when the column floods.

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