Rich-Amine Letdown in Refineries and Gas Processing Plants

The challenge of the rich-amine application is a complex one; the process begins when amine liquid is pumped into the top of a column and raw gas enters along the bottom, passing through the amine liquid as it rises. This process removes H2S and CO2 from the gas and absorbs it into the amine liquid, allowing the gas to leave the column “clean” and ready for distribution or use in a refinery. The remaining amine at the bottom of the column is now referred to as “rich amine.”

The column is maintained under pressure to improve the efficiency of the absorption process. At this pressure and saturation point, the rich amine is a multi-constituent fluid with a vapor pressure close to that in the column. As the fluid passes through the rich amine letdown valve, the pressure drops across it, causing the gases to be released from the amine.

If a valve’s design is based on a presumed lower vapor pressure, catastrophic consequences can result, such as high mechanical vibration that shuts down the train. DRAG® technology provides the number of pressure-reducing stages required to limit the kinetic energy produced, providing the needed reliability to keep production running and producing profit.

Published in SOLUTIONS Summer 2002