Pipeline Corrosion occurs when a pipeline’s material begins to deteriorate or weaken over time due to chemical reactions with its surroundings.
Corrosion is a significant challenge faced by industries that use process equipment and pipelines. Failure to manage corrosion can lead to leaks, explosions, and costly downtime.
According to a study conducted by NACE International, the global cost of corrosion was estimated to be $2.5 trillion, or over 3 percent of the global GDP in 2013. Therefore, understanding and managing corrosion can help save millions of dollars in reduced capital costs and reduced downtime.
What is Pipeline Corrosion, and what causes it?
Corrosion of pipelines, pipes, or really any corrosion is, simply stated, the degradation of metals into more chemically stable oxides through interaction with their surroundings. In the case of process piping and pipelines, we are most often concerned with the fluids carried by the pipe.
Various processes can cause and contribute to corrosion:
- Chemical reactions: Interactions with the fluid being transported through pipes with chemicals in the environment can cause corrosion. For example, oxygen, carbon dioxide, hydrogen sulfide, and organic acids carried in process fluids can all lead to corrosion, as can contact with seawater or corrosive soils.
- Microbial corrosion: Certain bacteria in process fluids can produce acids that lead to pipeline corrosion.
- Abrasion: Particles or fluids flowing through pipelines can abrade the pipelines and lead to pipeline corrosion.
- Electrochemical reactions: When different types of metals are in contact with each other electrochemical reactions can occur, leading to corrosion.
- Lack of maintenance: Failure to maintain pipelines can also contribute to pipeline corrosion.
How can corrosion be managed?
Managing pipeline corrosion requires a well-informed approach, and many of the processes that cause corrosion can be modeled to produce estimates of corrosion rates.
Understanding the processes that lead to corrosion allows for the development of preventative maintenance programs to manage corrosion. A number of factors should be considered in any corrosion mitigation strategy:
- Materials Selection: Pipelines, wells, and other process equipment can be designed and constructed from various alloys, with or without protective pipe coatings. The cost of each variety of pipe can vary widely, and selecting appropriate materials can impact project viability.
- Corrosion Inhibitors: These chemicals can be added to the fluids carried in pipelines to lower corrosion rates.
- Pipe Coatings: Protective coatings, such as cement or epoxy coatings, can be applied to pipes to help prevent pipeline corrosion.
- Inspection and Monitoring: Process equipment can be inspected using nondestructive testing, visual observations, or material sampling to identify corrosion rates. Corrosion models can be calibrated using real-life observations to optimize future inspection schedules and prevent unexpected downtime.
- Scheduled Maintenance: Appropriately scheduled cleaning and maintenance of pipelines can help prevent corrosion. Activities such as pigging pipelines to remove built-up debris and the application of film-forming corrosion inhibitors can significantly reduce pipeline or pipe corrosion rates and increase equipment lifespan.
However, the first step in the mitigating strategy should always be to start predicting the internal pipe corrosion rates.
How can Pipeline Corrosion be predicted?
Basic predictive models should account for CO2 corrosion, H2S corrosion, organic acid corrosion, O2 corrosion, and microbiologically induced corrosion in predicting internal pipeline corrosion.
More advanced corrosion models are able to model the following processes:
- Water chemistry is based on released Fe2+ from corrosion.
- Multiphase flow.
- Temperature gradients.
- Water/alcohol phase distribution and condensation.
- Organic acid partitioning in water/gas/oil phases.
- Top of Line Corrosion.
Pipeline Corrosion Prediction Software: Hydrocor
Hydrocor is a comprehensive cloud-based software solution for the calculation of internal corrosion rates in pipes, pipelines, and wells. Hydrocor can calculate corrosion rates by applying models that take into account CO2 corrosion, H2S corrosion, organic acid corrosion, O2 corrosion, and microbiologically-induced corrosion. It also includes all of the advanced corrosion models mentioned above.
Hydrocor can help select the right materials for processes during the design stage of a project. It can also calculate pipe/pipeline corrosion rates in existing systems and help in the implementation of corrosion mitigation strategies.
Hydrocor complements Cenosco’s Asset Integrity Management System, a suite of tools that allow industries to gain control of their assets and keep people safe. Used together with IMS PLSS: Pipeline and Subsea Integrity System, Cenosco can help the industry comply with complicated industrial and environmental regulations in any jurisdiction.
Cenosco is an asset integrity management software company with over 20 years of product leadership in asset-heavy industries.
Their IMS Suite of solutions was designed to support users in making smart inspection and maintenance decisions to increase safety, asset availability, and lowering asset management costs.
It is currently utilized to safeguard several hundred assets in over 50 countries. The IMS Suite was created in collaboration with world-renowned Oil & Gas leader Shell.
