In natural gas processing, removing water vapor from raw gas is essential to prevent hydrate formation, corrosion, and pipeline blockages. One of the most widely used technologies for gas dehydration is the TEG (Triethylene Glycol) system, where the core unit is the TEG Absorber, also known as the Glycol Contactor or Glycol Absorption Tower.

This article provides a technical overview of what a TEG absorber is, how it works, and where it is used.

1. What Is a TEG Absorber?

A TEG Absorber is a vertical tower that uses triethylene glycol (TEG) to absorb and remove water vapor from natural gas.

The absorption process is based on the strong hygroscopic properties of TEG, which naturally attracts and holds water molecules.

Due to its structure, the absorber is also called:

• TEG Contactor Tower

• Glycol Absorption Column

• Gas Dehydration Tower

It is the first major unit in a TEG dehydration package, followed by the regenerator (still column), reboiler, and filters.

2. Main Components of a TEG Absorber

A typical absorber tower consists of the following key sections:

1) Tower Shell

A vertical pressure vessel (usually carbon steel or stainless steel), designed according to ASME or relevant pressure vessel codes.

2) Inlet Gas Distributor

Ensures even gas distribution and minimizes channeling as wet natural gas enters the tower.

3) Packing or Trays

TEG absorbers can use:

• Structured packing

• Random packing (Pall rings)

• Sieve trays or valve trays

Packing/trays provide a large surface area for gas–liquid contact, allowing TEG to efficiently absorb water vapor.

4) TEG Distributor

Located at the top of the tower.

Includes:

• TEG distributor tray

• Spray nozzles

• Distribution piping

It evenly distributes lean TEG over the packing or trays.

5) Internal Support & Mist Eliminator

• Liquid redistributors (for tall towers)

• Mist eliminator at the top to prevent glycol carryover into the dry gas outlet

6) Gas Outlet Nozzle

Dry gas exits the top of the tower and moves to downstream systems (pipeline, compression, or processing units).

7) TEG Sump / Bottom Outlet

Rich TEG (with absorbed water) collects at the bottom and flows to the regeneration system.

3. Working Principle of a TEG Absorber

The TEG absorber operates on countercurrent mass transfer:

① Wet Natural Gas Enters the Bottom

Incoming gas contains water vapor that must be removed to prevent hydrate formation and corrosion.

② Lean TEG Enters the Top

High-purity “lean TEG” (typically 98.5–99.9% concentration) is evenly distributed from the top of the tower.

③ Countercurrent Contact

As gas flows upward and TEG flows downward through the packing/trays:

• TEG absorbs water vapor from the gas

• Gas becomes dehydrated

• TEG becomes “rich” with absorbed water

④ Dry Gas Exits at the Top

A mist eliminator removes entrained glycol, ensuring dry, clean natural gas.

Typical outlet water content:

• < 7 lb/MMscf

• dew point below pipeline specification

⑤ Rich TEG Leaves the Bottom

Rich TEG is heated, flashed, and regenerated in the reboiler + still column to restore dehydration capacity.

4. Advantages of TEG Absorption Technology

1) Continuous Operation

Provides stable 24/7 dehydration for gas plants and pipelines.

2) Low Operating Cost

TEG is regenerated and reused in a closed-loop cycle.

3) High Water Removal Efficiency

Achieves very low water dew points suitable for transmission pipelines.

4) Large Capacity

Ideal for large gas flow rates, from small wellhead units to midstream plants.

5) Flexible Design

Can use trays or packing depending on pressure, capacity, and efficiency requirements.

5. Typical Applications

TEG absorbers are widely used in:

• Natural gas gathering systems

• Gas processing plants

• Pipeline dehydration stations

• LNG pretreatment facilities

• Offshore platforms and FPSO units

• Wellhead production skids

Anywhere water vapor must be removed from gas, TEG absorbers remain the industry standard.