Glycol injection is provided by the injection pumps with the minimum to maximum flow rates of each pump ranging 0.19 – 0.69 m3/hr according to design. The rich glycol is separated from the condensate in the Cold Separators, about 35-120 minutes retention time dependent on the EG circulation rate, this is provided for the glycol to ensure proper separation of the glycol and condensate. The glycol exits the Cold Separators, under level control and flows to the reflux coils above the packing in the still columns of the EG Re boilers where self refluxing occurs.
Flow sheet of MEG regeneration process in natural gas processing
The rich glycol is then passed through integral lean/rich glycol coils in the surge tank section of the M.E.G Re-boilers. After being preheated by the lean M.E.G. in the accumulator the rich glycol stream flows to the
Glycol Flash Tanks which are operating at a lower pressure of 448 kPa (65 PSIG). In the flash tank, any free gases that exist are flashed off and sent to flare. Any liquid hydrocarbons that have been carried over into the flash tank can also be removed. Under level controls valves, glycol exits the bottom of the flash tanks and flows to the glycol filters. Particulate filters (10 micron), and carbon filters filtering dust particles and hydrocarbons contained in rich glycol ready to be boiled.
Glycol Flash Tanks which are operating at a lower pressure of 448 kPa (65 PSIG). In the flash tank, any free gases that exist are flashed off and sent to flare. Any liquid hydrocarbons that have been carried over into the flash tank can also be removed. Under level controls valves, glycol exits the bottom of the flash tanks and flows to the glycol filters. Particulate filters (10 micron), and carbon filters filtering dust particles and hydrocarbons contained in rich glycol ready to be boiled.
Upon exiting the filters, the rich glycol proceeds to the top of the packed section in the glycol still column. In the glycol still column, water is stripped out of the rich MEG as it flows downward through the 10’-0” packed section consisting of 25mm Pall rings counter current to the steam that is generated in the MEG Re boilers. The steam is discharged to the low-pressure flare header at the top of the still column. Once the desired concentration (temperature) is achieved in the MEG Re boilers. Lean MEG flows by gravity to the glycol surge tank (integral with the glycol re concentrator). Here it is cooled by heat exchange with the rich MEG flowing through the integral lean/rich glycol coils. From the surge tank the glycol flows to the suction of the glycol pumps where it is pressurized for re-injection in the Gas/Gas Exchangers.