Function and Purpose

During glycol regeneration, the reboiler heats rich glycol to drive off absorbed water. Without a reflux coil, some glycol vapors escape with water vapor in the overhead, reducing system efficiency and increasing glycol losses. The reflux coil uses cooling water or ambient air to selectively condense glycol vapors, returning them to the regenerator while water vapor passes to the atmosphere. This simple addition can boost lean glycol concentration from standard 98.5-98.7% to 99.0-99.5%, enabling outlet gas dew points below -40°C.

Design Configuration

ERGIL reflux coils consist of helical or straight tube bundles positioned in the regenerator vapor outlet line. Stainless steel construction resists corrosion from hot glycol vapors and condensate. Cooling medium flows through the tubes while glycol-laden vapor passes over the exterior surface. Shell-and-tube or air-cooled configurations available depending on site utilities. Condensed glycol drains back to the regenerator by gravity, requiring no additional pumping equipment.

Performance Benefits

Higher lean glycol concentration improves contactor dehydration efficiency, reducing required glycol circulation rates and reboiler fuel consumption. Enhanced water removal capability meets stringent pipeline specifications without auxiliary equipment. Reduced glycol carryover losses lower makeup chemical costs. Simple passive operation with no moving parts or controls required. Immediate performance improvement on existing dehydration units through retrofit installation.

Applications

Natural gas dehydration systems requiring low dew points for cold climate operations, high-pressure pipelines with strict water content specifications, offshore platforms where makeup glycol supply is limited, and facilities upgrading performance without major equipment replacement. Particularly effective in units operating at standard atmospheric regenerator pressure where boiling point limitations restrict lean glycol concentration.

Engineering Considerations

ERGIL sizes reflux coils based on regenerator vapor flow rate, available cooling medium temperature, and target lean glycol concentration. Heat transfer calculations determine required surface area. Proper vapor-liquid separation design prevents glycol re-entrainment. Condensate drain connections sized to prevent liquid backup. Materials compatible with hot glycol service typically 190-200°C vapor temperatures.

Installation Options

Factory-supplied as part of new dehydration packages or retrofit units for existing systems. Vertical or horizontal mounting configurations adapt to available space. Cooling water systems include inlet/outlet connections, flow control, and temperature monitoring. Air-cooled designs incorporate finned tubes with natural or forced convection. Minimal piping modifications required for most installations.

Operational Advantages

Passive operation requires no operator intervention or energy input beyond cooling medium. No maintenance beyond periodic inspection for fouling or corrosion. Immediate improvement in dehydration performance upon installation. Compatible with all standard TEG dehydration systems regardless of manufacturer. Cost-effective performance enhancement compared to alternative technologies like stripping gas or vacuum regeneration.

ERGIL reflux coils provide proven technology for optimizing glycol dehydration unit performance with minimal complexity and maximum reliability.