Condensate Stabilizer Units Explained

Condensate Stabilizer Units Explained

Jun 30, 2015 | Condensate Stabilization

Condensate stabilization units are an important tool in making condensate from natural gas streams easier to manage. Designs vary, but the goals of implementing a stabilization unit are usually the same: increase recovery of hydrocarbons, remove corrosive components, and create transport-ready product. Carbon dioxide and hydrogen sulfide corrode transport infrastructure, and lighter hydrocarbons like methane in the condensate are more dangerous to handle. Removing these while optimizing recovery of constituents like methane and propane means safer product and more profitable operations.

Raw natural gas liquids (NGLs) are introduced into the stabilization unit at a high pressure through a shutdown valve and preheated to a specific temperature. Afterwards, the pressure of the liquid feed is dropped via a control valve, creating both a liquid and gas phase. At this point water can be flashed out and removed from the stream, while any light gasses that escape can be flashed off or recovered. The remaining hydrocarbon liquids are then heated through a bottom exchanger before entering into a contactor or stabilizer tower. Tower designs can vary from tray to packed column, but the idea is generally the same: a reboiler heats the hydrocarbon liquid, causing two separate phases again. Lighter hydrocarbons with lower boiling points rise up the tower as a gas, while the heavier hydrocarbons contact the trays or packing in the column, collect, and stream down to the bottom of the tower as a liquid. Using either flash drum liquids or another technique, the NGLs are cooled and routed to a pipeline or storage facility. The vapor that rose through the tower may be flashed off in a downstream flare (if permitted by regulations) or routed to an NGL recovery skid designed to compress and store the lighter hydrocarbons for later processing or use.

Modern designs of condensate stabilizer units have several advantages. They are increasingly designed to be of a pretested, skid-mounted, modular design for rapid installation and start-up. These modular units can be ordered based on specific needs, from low BPD well-site recovery to high BPD midstream NGL processing. Hot or heat medium oil systems help reduce emissions, while compression cycles can be optimized with digital control systems. Additional equipment can be added or modified for special-case scenarios as well.