Pipeline Corrosion occurs when a pipeline’s material begins to deteriorate or weaken over time due to chemical reactions with its surroundings.
Process industries and pipeline operators battle corrosion as one of their biggest challenges. Failure to manage corrosion can lead to leaks, explosions, and costly downtime.
A NACE International study from 2013 pegged global corrosion costs at $2.5 trillion, over 3% of worldwide GDP. 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. Process piping and pipelines demand we focus primarily on the fluids they transport.
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?
Pipeline corrosion management requires a well-informed approach. On top of that, you can model key processes to calculate corrosion rates.
Understanding the processes that lead to corrosion allows for the development of preventative maintenance programs to manage corrosion. Any corrosion mitigation strategy should consider several key factors:
- 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 the 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.
Hydrocor – Pipe Corrosion Prediction software
Hydrocor is a comprehensive cloud-based software solution that calculates internal corrosion rates in pipes, pipelines, and wells. It 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 to keep people safe. Used together with IMS’s Pipeline and Subsea Integrity System, Cenosco can help industry comply with complicated industrial and environmental regulations in any jurisdiction.
Tomislav Renić Technical Writer
Tomislav is an experienced engineer and technical communicator with over 20 years in complex systems, modeling, and project management. As a Technical Writer at Cenosco, he translates engineering concepts into clear, user-friendly documentation for software in the oil, gas, and refining industries.
