The MEG Reclamation Unit (MRU) removes salts from the Lean MEG feed stream entering the unit and produces a virtually salt-free Lean MEG product that can be recycled back to the wellheads.
Pretreatment: Salty Lean MEG enters the MRU from the MEG Regeneration Unit. A small amount of Caustic is injected to achieve a pH of approximately 11-12. This target pH ensures that any Calcium ions present in the feed precipitate as Calcium Chloride within the .
Primary Flash: Lean MEG from the Pretreatment area, following passage through a slurry cooler which assists in preheating the Salty Lean MEG is injected directly into the Reclaimer Flash Vessel. Vapors exiting the Flash Vessel are directed into the Condenser. The Condenser operates at sub-atmospheric pressure. This allows the MEG/water mixture entering the Flash Vessel to vaporize at a temperature well below the degradation temperature of MEG (about 165 o C). Upon flashing, water and MEG will vaporize while Salts and other solids contained in the inlet stream will not vaporize and instead become concentrated in the circulating inventory of the vessel.
MEG/H2O/salt slurry is continuously pumped from the bottom of the Reclaimer through the Reclaimer Circulation Heater by the Reclaimer Circulation Pump.
Upon entering the Reclaimer Flash Vessel, the water and MEG contained in the slurry will vaporize and flow upward through the vessel while the residual droplets of MEG/H2O/salt slurry fall into the liquid pool in the base of the vessel. As a result, the salt and solids concentration of the liquid pool increases.
A portion of the MEG/H2O/salt slurry flowing through the recirculation loop is diverted to the Solids Handling area
Solid Handling Area: As MEG and water are vaporized in the Reclaimer, the slurry circulating in the recirculation loop becomes increasingly concentrated. Salts can then be removed from the thickened slurry through the slurry cooler exchanger and then finally removed.
A continuous “purge loop” of slurry is pumped from the Circulation Pumps to the Solids Handling system of the plant and back to the Reclaimer. Maintaining a continuous flow ensures that solids do not settle in the lines leading to Solids Handling system during low-flow, or intermittent flow conditions.
Product Handling: Vapors exit from the Reclaimer and enter the Reclaimer Condenser. The exit from the Reclaimer Condenser enters the Product Receiver where the salt-free Lean MEG is separated from any non-condensable vapors and pumped via the Lean MEG Pump to the battery limit.