Dehydration Purpose

Natural gas saturated with water vapor forms hydrates at high pressure and low temperature blocking pipelines and equipment. Pipeline specifications require water content under 7 pounds per MMSCF (approximately -20C to -40C dewpoint). Glycol dehydration achieves target dryness.

Process Description

Wet gas enters contactor tower flowing upward through trays or packing. Lean glycol sprays downward from top absorbing water from gas. Dry gas exits overhead meeting pipeline dewpoint. Rich glycol saturated with water flows to regeneration system.

Contactor Tower

Vertical column with 4-8 bubble-cap or valve trays providing gas-liquid contact. Alternatively structured or random packing. Glycol enters top distributor. Gas enters bottom with inlet separator removing liquids. Pressure typically 300-1500 psig.

Glycol Regeneration

Rich glycol heats through lean-rich exchanger then enters flash separator venting dissolved gas. Flows to regenerator column with reboiler stripping absorbed water. Lean glycol exits at 198-204C achieving 98.5-99% purity.

Reboiler System

Indirect-fired with natural gas or electric heating. Fire-tube design for gas-fired units. Temperature control maintains 198-204C preventing glycol thermal degradation while achieving water removal. Stripping gas optional improving regeneration to 99.5% purity.

Glycol Circulation

Lean glycol pump returns regenerated glycol through cooler to contactor. Circulation rate 2-4 gallons per pound water removed. Higher rates improve dewpoint depression. Glycol cooler reduces temperature to 10-15C above inlet gas.

Material Construction

Carbon steel vessels and piping for standard service. Stainless steel components for sour gas with H2S and CO2. Contactor internals resist corrosion. All equipment rated for operating pressure.

Skid Package

Complete integrated system - contactor, flash separator, regenerator, reboiler, pumps, heat exchangers, instrumentation, and controls mounted on structural skid. Factory-assembled, tested, and ready for field installation.

Operating Capacity

Units sized 0.5-100 MMSCFD gas flow. Larger custom designs available. Water removal 20-200 pounds per day depending on inlet gas moisture and pressure. Achieves dewpoint depression 50-120F below inlet temperature.

Applications

Natural gas production dehydration, gas gathering system conditioning, wellhead gas treatment, offshore platform gas processing, compressor station inlet drying, and any natural gas requiring moisture removal.

Instrumentation

Temperature and pressure indicators throughout system. Level control on flash separator and regenerator. Glycol circulation rate monitoring. Optional dewpoint analyzer verifying outlet gas quality.

Control Systems

Automated glycol circulation control. Reboiler temperature management. Safety shutdowns for high temperature, low level, and flame failure. PLC-based systems for unmanned operation.

Glycol Selection

Triethylene glycol (TEG) standard for most applications achieving -40C to -60C dewpoint. Diethylene glycol (DEG) for moderate requirements. Ethylene glycol (MEG) rarely used. TEG offers best balance of performance and economics.

Glycol Losses

Vaporization losses with gas typically 0.5-2 gallons per MMSCF. Liquid carryover minimized through proper contactor design. Regular makeup maintains inventory. Glycol reclaiming removes contaminants extending life.

Performance Benefits

Achieves pipeline gas dewpoint specifications. Prevents hydrate formation in transmission. Protects compressors and equipment from liquid water. Reliable proven glycol absorption technology.

Standards Compliance

Design per API standards for gas processing equipment. Pressure vessels per ASME Section VIII. Fired equipment per applicable codes. Complete documentation with performance guarantees.

ERGIL natural gas glycol dehydration units provide reliable water vapor removal meeting pipeline specifications and preventing hydrates in natural gas production and transmission.