Stripping Gas Technology

Standard glycol regeneration at atmospheric pressure limits lean glycol concentration to approximately 98.7% due to water-glycol vapor pressure equilibrium. Introducing stripping gas (typically natural gas, nitrogen, or dry air) into the reboiler section reduces water partial pressure, allowing additional water removal at the same temperature. The gas flows upward through the column, carrying water vapor overhead while glycol remains in liquid phase. This proven enhancement achieves 99.5-99.9% lean glycol concentration without expensive vacuum equipment.

Column Configuration

ERGIL stripping columns feature extended height with additional trays or packing stages compared to standard stills. The reboiler section includes gas injection nozzles distributing stripping gas uniformly. Gas flows countercurrent to descending glycol, maximizing mass transfer efficiency. Overhead vapor containing water and stripping gas exits to disposal or recovery systems. Column internals resist high temperatures while providing intimate gas-liquid contact.

Process Design

Stripping gas rates typically 2-10 SCFH per gallon of glycol circulation. ERGIL calculates optimal gas injection rates based on target glycol concentration and available stripping gas composition. Temperature control maintains 190-204°C to prevent glycol degradation while maximizing water removal. Column sizing accounts for increased vapor loading from stripping gas flow.

Equipment Integration

Complete systems include stripping column with gas injection, flow control and metering, temperature monitoring, overhead vapor handling, and safety relief protection. Gas preheat may be included to improve efficiency. For natural gas stripping, glycol dehydration occurs before gas injection to prevent water reabsorption. ERGIL provides full process design integrating stripping systems with existing dehydration units or new installations.

Applications

Ultra-low dew point requirements for arctic pipelines and cryogenic processing, high-pressure gas transmission systems with stringent water specifications, offshore platforms maximizing performance in space-constrained installations, and facilities upgrading existing units without major equipment replacement. Particularly cost-effective where natural gas is readily available as stripping medium.

Performance Benefits

Achieves glycol purities impossible with atmospheric regeneration alone. Lower required glycol circulation rates reduce pump energy and heat duty. Smaller contactor vessels possible due to enhanced glycol quality. Reduced glycol carryover into gas stream. Operates at atmospheric pressure avoiding vacuum system complexity and maintenance.

Operational Considerations

Stripping gas consumption represents ongoing operating cost. Natural gas stripping requires dehydrated gas supply to prevent contamination. Nitrogen stripping offers inert operation but requires supply infrastructure. Increased overhead vapor volumes need adequate disposal capacity. Additional instrumentation monitors gas flow and distribution uniformity.

ERGIL stripping columns provide proven technology for achieving maximum glycol purity and ultra-low gas dew points with reliable, cost-effective operation.