There are varieties of pipeline coatings. Lets first clarify the purpose of pipeline coating. A pipeline is a network of pipes utilized for transporting liquids like oil, natural gas or other petroleum based products across distances underground. It has been a part of society, for millennia initially used for water transportation.
Pipelines are generally more costly than surface roads or water routes. Planning a pipeline construction project involves considerations of social, developmental, environmental aspects and safety measures. Can span several years with numerous surveys and studies before completion. However constructing pipelines can lead to cost savings by choosing more routes or utilizing existing channels.
Establishing a pipeline system for large-scale water supply projects or oil distribution is an effort that demands financial investments, among other resources. It aids in mitigating corrosion within pipelines. Pipelines are categorized based on the materials used in their construction the substances they transport and their operational purposes.
Various Types of Pipeline Coatings
What Are the Different Types of Pipeline Coatings?
Different types of pipeline coatings are chosen based on factors such, as the material used for coating, pipeline design external forces acting on the pipeline connectivity, process development, durability, impermeability and maintenance frequency.
Here are the primary categories of pipeline coatings;
- Wastewater Pipeline; This type of coating is suitable for wastewater transportation systems that primarily consist of water with waste content. The pipes can be constructed using materials like concrete, PVC cast iron or clay based on factors such as pressure levels and other considerations.
- Petroleum Oil Pipeline; These pipelines are typically made of steel coated with cathodic protection to prevent corrosion. Welding is commonly used to connect sections of oil pipelines. They can be classified into two types; crude oil pipelines that transport oil to refineries and product pipelines that transport items like gasoline to markets.
- Liquid Epoxy Coating; The process for applying epoxy coatings is relatively straightforward. When applied onto surfaces, mixing epoxy resin with a hardener or catalyst initiates a chemical reaction that forms a layer. Epoxy can be applied using methods such, as brushing, rolling or spraying after mixing.
Liquid epoxy is commonly used in applications such, as welding size cover, fittings, valves and repairing sections of tubes. It also becomes a layer when underground plumbing meets the air above ground.
Epoxy Coal Tar
Coal tar epoxy (CTE) is a type of epoxy that replaces some mineral fillers with liquid coal tar pitch. When resin and hardener are combined (parts A and B) CTE forms a thermoset coating of bonded epoxy resins. The thickness of coal tar epoxy coatings like epoxies depends on particle content and the number of applications applied to steel.
For pipeline work CTE coatings typically range from 15 to 35 mils thick. The curing process for coal tar epoxy is relatively slow, requiring five to seven days to cure at temperatures (e.g., 75°F). Accelerated curing at 150°F can reduce time to 8 hours.
Polyolefin Three-Layer Coatings
A three layer coating system known as polyolefin consists of a primer (FBE or liquid epoxy) an layer made of copolymer and a topcoat.This type of coating has been commonly used in pipelines with resistance since the 1980s. The initial step, in applying three layer coatings, such as FBE coatings involves preheating the pipes.
The FBE and copolymer layers are sprayed on followed by a topcoat (the tie layer can be applied through side extrusion). Polyethylene is often used as a topcoat while polypropylene is preferred for pipelines exposed to service temperatures.
Galvanizing
One of the steel pipe coatings is galvanizing or applying several layers of zinc. Despite the metals corrosion resistance and tensile strength properties it still benefits from a zinc coating for finishing. Galvanizing can be done using methods based on availability.
The employed method is hot dip or batch dip galvanizing, which entails immersing a steel pipe in molten zinc. A metallurgical reaction between the steel pipe alloy and zinc results, in a surface finish that enhances the metals corrosion qualities like never before.
Another advantage of galvanizing is cost efficiency. Many companies opt for this method because it is straightforward and does not necessitate operations or post-processing tasks.
Epoxies With Fusion Bonding
This particular type of pipeline coating is considered notch. Fusion bonded epoxies are a type of component, heat curable thermosetting epoxy. These epoxies are applied to surfaces in powder form (10 40 mils). Quickly solidify from liquid, to solid. They have adhesion to steel surfaces. Provide strong protection against damage during handling. Additionally they are environmentally friendly as they do not contain components (VOCs).
To prevent the pipes from cooling, it is recommended that the FBE coating be applied after the heating process. Using automated application tools like application rings, electrostatic guns, or flocking machines can help apply the powder evenly. The coating should have a thickness of 14 to 16 mils.
Typically, multiple passes are required when applying FBE material, with each pass being around 2 to 5 mils thick and done swiftly. Depending on the material’s formulation, the FBE coating will usually dry within a minute and fully cure in three minutes or less. Once the applied coating has cooled down to 200°F, it can be tested.
In pipeline construction projects, knowing the types of coatings is essential for ensuring durability and optimal performance.
One notable solution within this field is the Lined Pipe Systems, an approach to coated pipelines. This system introduces a way of constructing pipelines by combining the benefits of Quick Installation and lasting Protection.
The Lined Pipe Systems feature groundbreaking weld joint sleeve inserts that redefine the construction of pipelines. Apart from shielding against corrosion, these systems enable the use of quick and conventional construction methods. The pipe joint sleeve inserts do not expedite construction but also offer robust protection, ensuring lasting defense for the welded area.
This blend of installation and enduring safeguard makes Lined Pipe Systems an effective solution for various industrial uses. Delving into pipeline coatings incorporating systems, especially the pipe weld joint sleeve inserts, brings a fresh perspective to available options, underlining the significance of both speed and resilience in pipeline construction.
In conclusion
To provide drinking water coating materials are formulated for contact, with water. Testing is conducted on water to assess any tanks or chemicals that may leach into it. Examples of coatings include coal tar enamel, cement mortar, liquid applied epoxy, fusion bonded epoxy (FBE) or polyurethane (PU).
Before proceeding with any evaluation, it is crucial to conduct an assessment of the chemical concentrations in the examples provided. Subsequently, NSF toxicologists perform a formulation evaluation to outline the chemical studies involved.
Once the product is ready for testing, it undergoes examination for metal control by exposure to water glasses with pH levels of 5 and 10. This process helps in evaluating the outcomes. It’s important to note that each type of coating comes with its set of advantages and disadvantages in terms of performance and application. Therefore it is essential to consider these factors when selecting a coating, for the specific service environment required.