Protective Epoxy Coatings For Oil and Gas Pipelines

Master Bond Chemical and Heat Resistance Protective Epoxy Coatings For Oil and Gas Pipelines Fully Curable at Ambient Temperatures.

Epoxy coatings for oil and gas applications offer excellent resistance to high temperatures, chemicals and corrosion.

Current protective coating technology for oil and gas pipelines is recognized to have both technical and economic disadvantages. Many factors contribute to the complexity of designing efficient pipeline coating formulations; climate, properties of the substrate traveling through the pipeline, product flammability and rate of flow to name a few. In addition it must be taken into consideration if the pipeline is laid underwater, under ground or above ground and the coating must be formulated to provide long term internal and external durability, the coating must be formulated with some basic tenets in mind. Some factors contributing to the complexity of this industry are briefly addressed below.

• Climate, temperature and physical location of the pipeline. Master Bond offers products that can be applied and function in these diverse climates. Pipelines can be run underground, underwater or above ground. Each installation application presents its own unique pipeline coating challenges.
• Physical state of fluid being transported through the pipeline; liquid and gaseous fuels are not harvested in a clean state. There are impurities present in harvested fluid. When flowing at high speed through a pipeline, these particulates become abrasive. Master bond offers formulations that are highly resistant to the corrosive nature of a variety of particulates at high flow rates or to liquefied natural gas, which is transported at cryogenic temperatures.
• Viscosity: Efficient pipeline coatings need to be appropriate for a wide range of fluid viscosities.
• Flammability: Both the fluid in the pipeline and the coating material prior to curing may be extremely flammable. Many coating methods to date require application of open flame. This creates a potential fire hazard at the work site. For this application, Master Bond’s formulations are not flammable.

Internal and External Protective Pipeline Coatings

Oil and gas protective pipeline coatings must be divided into two separate categories, each with its own unique and demanding requirements: Internal Coatings and External Coatings.

Internal Coatings:

Oil and gas fluids contain solid particulates such as sodium chloride, potassium chloride, other salts, carbonates, sulfates, partially polymerized oils, including waxes and paraffins as well as silicas, dirt and greases. Some of these particulates dissolve in the fluid while some remain in suspension. Traveling through pipelines at speeds approaching 200 mph, these particulates become aggressively corrosive projectiles. Coatings designed for internal pipeline application must be engineered to withstand the high impact created by these fast moving particulates.

External Coatings:

Oil and gas pipelines are found across the globe. Pipelines can run above ground, underground or they can be immersed in fresh or salt water. Coatings designed for external pipeline applications must be engineered to withstand this wide variety of environmental conditions. Soil stress, soil born chemicals and salt water present formidable challenges to the performance of external pipeline coatings. External coatings also need to be resistant to indigenous bacteria, other flora, waste water and to the chemicals and solvents used in the processing of the hydrocarbons. Pipelines can be found in the hot desert where temperatures often exceed 100°F or in Alaska where temperature can reach as low as -76°F. Ground conditions in the permafrost regions, where ground temperature rarely exceeds 32°F, make subterranean application of pipe very difficult and almost mandate above ground pipeline installations.

Current Technology

There are currently four popular methods for coating pipelines:

1) Three-Layer PE (3LPE)/PP (3LPP)

PROS:

• Relatively low material cost
• Relatively low application cost

CONS:

• Requires application of flame to create adhesion
• Application of flame in pipeline environments has traditionally been the cause of workplace fires and explosions
• Offers limited heat resistance
• Maximum 225°F – 250°F
• Lacks dimensional stability
• Offers borderline hardness
• Provides limited resistance to Sulfur, Amines, etc.
• Provides limited resistance to Oxygen and other oxidants

2) Fusion Bonded Epoxy (FBE)

PROS:

• Excellent chemical resistance
• Better dimensional stability – minimal hysteresis

CONS:

• Relatively Expensive
• Material expensive
• Pipe and coating must be heated to 250°F
• High labor requirement

3) Coal Tar Enamel (CTE)

PROS:

• Extremely inexpensive

CONS:

• Minimum protection
• Highly Toxic and Flammable

4) Asphalt Enamel and Polyurethane (PUR)

PROS:

• Inexpensive
• Better than Coal Tar Enamel
• Decreased hysteresis
• Fast cure

CONS:

• Poor chemical resistance
• Severe temperature limitations
• No dimensional stability

Recent Developments

Easy to apply epoxy coatings are formulated in various viscosities and colors for high performance coating applications which require superior temperature and chemical resistance.

Over the last 5-10 years, as the safety requirements have become more stringent and chemical resistance more demanding, Master Bond has developed a number of products geared toward meeting more specialized pipeline applications. These products will outperform existing technologies and be safer to use and are geared more toward specialty types of markets, especially with pipelines carrying oils, natural gas, LNG and a host of other ethanol chemicals. To obtain significantly higher levels of performance, the products should be applied at ambient temperatures; also some heat should be added to optimize curing, chemical resistance and other physical properties. Our specialty is two component epoxies that are designed to be applied by brushing or spraying. They are less toxic, improve efficiency and productivity for manufacturing companies and provide far superior products in comparison to presently available systems.

One of the highest performance oil related products Master Bond offers is Supreme 45HTQ. It also is widely used in a large number of varied down-hole applications because of its exceptional temperature and chemical resistance. It is eminently well suited for pipeline coatings. As alluded to previously, it is also less hazardous than many alternative methods. It should be noted that the actual application should be done indoors, mixing is needed and heat has to be added for curing.

A second product that is also available is EP29LPSP, which is a top of the line epoxy coating for cryogenic applications. It has a lengthy history of use in situations involving LNG and other cryogenic substances. As is well known, the USA has huge reservoirs of natural gas. The extraction and transport of LNG is an industry of continuing growth. Pipelines involving LNG transport have increased dramatically in the last decade and are expected to continue to grow in the future. The EP29LPSP has a lengthy track record of success as a coating in this kind of environment.

A third system available is EP41S-1HT which is specifically blended to resist fuels that contain Ethanol. Ethanol is particularly aggressive when combined with gasoline. The EP41S-1HT has easily resisted years of exposure to gasohol when processed in the proper environments.

Master Bond’s innovative formulations have been in the forefront in optimizing protection and fulfilling the ever evolving requirements of this crucial industry. Technologically advanced compounds feature enhanced performance and have been designed to withstand exposure to hostile environmental conditions in special applications

(source : http://www.masterbond.com/articles/chemical-and-heat-resistance-protective-epoxy-coatings-oil-and-gas-pipelines)