Use of Glycols in Oil & Gas: How They Solve Critical Operational Problems

The problem of wax, hydrate, and corrosion creation does not occur all at once, these problems slowly develop over time, with moisture forming in the gas stream, turbulent flow in low temp areas, causing the potential for hydrates, and creating an unstable environment for everything along the pipeline, eventually causing disruption to operation, creating problems with equipment, and increasing the amount of time that an oilfield is not producing oil or gas.

The use of glycols in oil and gas is extremely important. Glycol should not be considered as an optional supplement or secondary chemical; glycol should be viewed as a vital substance that is critical to maintaining safe, stable operations in these harsh environments.

With proper selection and application of various glycols, many long-standing operational issues can be addressed in upstream, midstream, and processing operations in the oil and gas industry.This article outlines the multiple applications of glycols in oil & gas and how they function as an integral part of reliable industrial operations.

What Are Glycols?

Glycol is an organic molecule that contains two hydroxyl (-OH) groups; therefore, they attract water very easily and have consistent thermal properties. Because of this, glycols serve as effective moisture control agents, temperature regulators, and flow assurance agents.

The oil and gas sector has the highest number of glycol applications. The four main glycols are mono-ethylene glycol (MEG), di-ethylene glycol (DEG), tri-ethylene glycol (TEG), and propylene glycol (PG). When determining the best product for an application within your facility or plant, you should carefully review the glycol selected based on how it will operate under different temperature ranges, pressure levels, environmental conditions, and types of processes supported.

Key Operational Problems Glycols Solve in Oil & Gas

1. Moisture Control and Gas Dehydration

Gas producers in the oil and gas industry have to manage the issue of a high level of moisture in their production stream. The presence of water in gaseous form, when not handled properly, may lead to corrosion, freeze-up, or hydrate formation, which are all damaging to producer operations.

Use of glycols for gas dehydration to remove moisture from gas streams and TEG or triethylene glycol is the most common product used by producers. Glycols are able to absorb moisture and therefore protect pipelines and valves, downstream equipment and meet the specifications required for natural gas products for end users.

2. Hydrate Prevention in Pipelines

Hydrates appear similar to ice; they are made up of a solid block of ice, which is formed by the combination of hydrocarbons (and in rare cases) and water, when under extreme conditions of heat and pressure, as well as under lower temperatures.

Hydrates can become an obstruction within the pipeline causing restrictions on flow or shutting off the entire operation.Use of glycols in oil & gas pipelines as hydrate inhibitors is highly advantageous. Glycol acts to lower the freezing point of water by disrupting the formation of hydrate crystals.

Injecting Glycol into oil & gas pipelines on a continual or seasonal basis, provides for continued flow throughout the entire operation, especially within Offshore, Subsea and Cold Climate applications.

3. Thermal Stability and Heat Transfer Applications

Temperature must be uniformly controlled throughout all parts of refinery or gas processing facilities, and use of glycols as the primary heat transfer fluid to allow for this stability in temperature, as well as to permit operation throughout a wide range of temperatures. Glycol-based heat transfer fluids are particularly useful in closed loop systems as they:

• Protection from freezing temperatures.
• Provide control over the transfer of heat.
• Diminish thermal stress on machinery.
• With these benefits, systems are more efficient and machinery lasts longer.

4. Corrosion Risk Reduction and Equipment Protection

Corrosion in Oil and Gas Is Driven Primarily By Mositure. Controlling Moisture Through Glycols. Glycols, By Controlling Moisture Content, Reduce the Risks Associated With Corrosion In Pipelines, Separators, and Process Equipment By Reducing Water Content. Glycol Combined With Corrosion Inhibitors Provide Additional Protection In Many Cases, Therefore Reducing Maintenance Frequency, Leakage and Long-Term Efficiency of Asset.

5. Process Stability and Flow Assurance

There are many variables that may cause the fluctuation of pressure and temperature; when production systems experience these fluctuations it can destabilize the system. Glycols will help stabilize the fluid behaviour, as well as help to maintain stable flow characteristics thus assisting in creating a more consistent production environment.

The applications of glycols in oil and gas production are flow assurance methods that improve predictability and enhance stability, allowing for smoother operation with minimal unplanned shutdowns.

Applications of Glycols in Oil & Gas Operations

Oil & Gas Industry Applications

• Natural gas dehydration systems
• Hydrate inhibition in pipelines and flowlines
• Flow assurance in offshore and subsea operations
• Heat transfer systems in refineries and gas plants
• Moisture control in processing units

Industrial and Utility Applications

• Heating and cooling systems
• Closed-loop heat transfer fluids
• Moisture control in industrial processes
• Chemical processing applications

Choosing the Right Glycol for Oil & Gas Applications

When choosing what type of glycol to use for an application there are many factors that should be taken into account, such as:

• Operating Temperature/Pressure (or both)
• Requirements to Remove Moisture
• Regulations for the Environment/Safety
• Compatibility with Existing Systems

If you choose the wrong glycol or a less than optimal concentration, it can reduce the efficiency of your system, and lead to complications. By selecting the correct glycol, you will ensure that your system will perform reliably and operate consistently.

Operational and Economic Benefits of Using Glycols

The correct use of glycols in oil and gas operations delivers measurable benefits:

• Reduced hydrate-related shutdowns
• Improved process efficiency
• Lower maintenance and repair costs
• Enhanced operational safety
• Extended equipment lifespan

These advantages make glycols a cost-effective solution for managing complex oil & gas challenges.

Conclusion

For operational challenges encountered in the oil and gas industry, glycols are an integral solution in many aspects of production and processing. Glycols are utilized to hydrate gases, control temperatures and maintain equipment throughout the full range of oil and gas production and processing.

Properly applied, glycols assist with flow assurance, protect assets and support sustained production without interruption (e.g., "hot" production, protected financially and from a production standpoint). Glycols are more than just visible products that perform a function; they're consistently utilized in many facets of the oil and gas industry, thus making them an integral component of a dependable infrastructure.

FAQs on Glycols in Oil & Gas

1. What is the main use of glycols in oil & gas?

The largest application of glycols in oil and gas industries is to remove moisture during the drying processes of natural gases. Glycols also provide a means of controlling the formation of hydrates and provide flow assurance in addition to providing corrosion protection to equipment.

2. What type of glycol is utilized for dehydration of gas?

The type of glycol typically used for gas dehydration is triethylene glycol (TEG), which is widely used because of its ability to absorb large amounts of moisture, and its effectiveness and reliability under a wide range of conditions.

3. How do glycols help you prevent hydrate formation?

Glycols help to reduce the freezing point of water and prevent the formation of hydrates by preventing water from crystallizing into solid blockages in high-pressure, low-temperature pipeline systems.

4. Glycols are primarily used in the Oil & Gas industries; do they have other applications?

Glycols are not unique to oil and gas; while they are used extensively in the oil and gas industries, they also can be found in other applications, including the control of temperature and moisture in heat-transfer systems, and utility operations across various industrial processes.

5. Why is it important to pick the right type of glycol?

Choosing the right type of glycol for your application is essential because there are different types of glycols for different temperature and concentration ranges. By using the appropriate glycol for your system, you will ensure proper operation of the equipment over an extended time and compatibility with other components in the system, reducing the risk of equipment failure and improving long-term performance and efficiency in general.