What’s the danger of having moisture in your natural gas pipeline?

Extreme cold weather can bring more than frozen streets and burst water pipes—it can expose systemic vulnerabilities in energy infrastructure. 

In February 2021, a historic winter storm hit Texas with record low temperatures and widespread snow and ice, driving power demand to unprecedented levels. Millions of residents lost electricity and heat for days. Subsequent investigations found that freeze-related failures across natural gas production, processing, and delivery systems were major contributors to the grid collapse.

Investigations and data from that event show freeze failures in natural gas production and supply chains were among the leading contributors to the grid collapse because critical equipment and pipelines were not prepared for sustained freezing and moisture issues. 

Bottom line: natural gas does contain water. If that moisture is not removed before the gas is put into service, it can condense and form liquid or ice when pressure drops or temperatures fall. 

Those phase changes can block valves, regulators, actuators, or smaller lines that feed heaters and generators, degrading performance or causing outages when reliability matters most.

Understanding why this happens starts with understanding where moisture in natural gas comes from.

Why Moisture Is Always Present in Natural Gas

Natural gas comes out of the ground saturated with water vapor. That moisture stays in the gas unless it is actively removed.

Operators define moisture specifications at specific pressures and temperatures, but those specifications only hold as long as conditions remain stable. Once pressure drops or temperature changes, the amount of water the gas can carry changes as well.

That is where problems begin.

How Pressure Drops Create Freeze-Up Risk

Freeze-ups follow a predictable sequence.

As natural gas flows through a system, it passes through regulators, valves, and orifices where pressure is reduced. Each pressure reduction causes a rapid temperature drop due to the Joule–Thomson effect.

It is also important to distinguish between atmospheric dew point and pressure dew point, since moisture in natural gas condenses based on pressure-dependent dew point inside the pipeline, not ambient conditions outside the line.

When temperature drops:

• The gas can no longer hold the same amount of water vapor
• Water vapor condenses into liquid
• Liquid water accumulates in lines and equipment
• In freezing conditions, that liquid turns to ice

A single frozen regulator or valve can shut down an entire system.

Cooling Happens Even Without Regulators

Freeze-ups are not limited to pressure reduction points.

Gas is often heated during compression. As it travels through pipelines, it gradually cools back toward ambient temperature. That cooling alone can cause moisture to condense, especially over long distances or during sudden weather changes.

Liquid water tends to collect in low points, equipment housings, and downstream components, creating localized freeze risks.

Why Moisture Causes Serious Operational Problems

Moisture in natural gas systems creates multiple issues:

• Ice formation that blocks flow
• Frozen regulators and valves
• Instrumentation failures
• Reduced combustion efficiency
• Corrosion of burners and downstream equipment

Freeze-ups are especially disruptive because they tend to happen quickly and can require depressurizing the system to correct.

How to Prevent Natural Gas Pipeline Freeze-Ups

Freeze-ups are prevented by removing moisture before it has a chance to condense or freeze.

Natural gas dehydration lowers the water content of the gas, reducing the risk of liquid formation as pressure and temperature change throughout the system. Because gas rarely operates at a single, steady condition, dehydration strategy matters just as much as dehydration itself.

Several dehydration technologies are used across the industry, each with strengths and limitations depending on application and operating environment.

The Limits of Fixed Dew Point Dehydration

Different dehydration approaches behave very differently when operating conditions change.

Triethylene glycol (TEG) dehydration is widely used and effective under steady-state conditions. These systems remove moisture to a fixed outlet specification based on defined pressure and temperature parameters.

The limitation is that the outlet dew point does not change when conditions change.

When temperatures drop sharply or fluctuate faster than the system was designed for, a fixed dew point may no longer provide sufficient margin. Moisture that was previously stable in vapor form can condense and freeze downstream, particularly at regulators, valves, and instrumentation points.

Why Deliquescent Dryers Are Used for Freeze-Up Protection

Deliquescent natural gas dryers take a different approach.

Rather than producing a fixed outlet dew point, deliquescent dryers suppress the dew point relative to the inlet gas temperature. As inlet temperature decreases, the outlet dew point decreases with it. This keeps the dew point below the gas temperature even as operating conditions shift.

That adaptive behavior makes deliquescent dryers well suited for freeze-up prevention, especially in systems exposed to unexpected cold, rapid temperature swings, or intermittent operation.

How a PLD Deliquescent Dryer Works

A PLD deliquescent dryer is a simple pressure vessel filled with solid desiccant tablets.

As wet gas passes through the dryer:

• Moisture is absorbed by the desiccant
• The tablets gradually dissolve, forming a liquid brine
• The brine collects in the bottom of the vessel and is drained

The system has no moving parts and requires no electrical power or controls.

Maintenance is straightforward. Desiccant tablets are replenished periodically, typically every four to six weeks depending on gas flow and inlet moisture content.

Where Deliquescent Dryers Make Sense

PLD deliquescent dryers are commonly used in applications where freeze-ups would create operational or safety risk, including:

• Primary dehydration in smaller systems
• Point-of-use drying for fuel gas
• Instrumentation and valve actuation gas
• Backup protection downstream of TEG dehydration

They are particularly useful in remote locations, systems without reliable power, and applications where simplicity and reliability are priorities.

Planning for Conditions You Didn’t Expect

Recent years have shown that historical climate patterns are not reliable predictors of future operating conditions.

Freeze-ups are not a cold-climate problem. They are a moisture problem.

Removing moisture is one of the simplest and most effective ways to reduce operational risk in natural gas systems. Whether used as a primary dryer or as a safeguard downstream of existing dehydration equipment, deliquescent dryers provide dependable protection when systems are pushed outside their normal operating envelope.

Reliability matters. Preparation matters. Moisture control makes the difference.