Top-Of-The Line Corrosion occurs in horizontal pipelines as significant heat exchanges take place between the pipeline
and its surroundings. For this specific kind of corrosion, the understanding of the thermodynamics and heat and mass transfer, and their
coupling with the chemistry of the condensed water, is crucial. The condensed water represents a corrosive environment that can differ
significantly from the water produced and lead to drastically different corrosion rates.
In the course of a long-term project conducted at Ohio University, the main factors controlling the corrosion rate by
CO2 of mild steel during wet gas transportation have been identified and reported.
In the first phase of the project, testing in the Top-of-the-line corrosion (TLC) project encompassed a broad range of
velocities and pressures, along with the inclusion of H2S, glycol, and acetic acid. Mitigation procedures such as pH stabilization
and inhibitor (standard and volatile) usage have been addressed. The project included the development of a mechanistic model to predict the
condensation and TLC rates. A mechanistic model has also been developed, validated, and upgraded against experimental data.
In the new phase of the project (starting in 2007), our knowledge acquired during the past 4 years of this JIP (mainly
focused on the understanding and modeling of the TLC mechanisms) will be merged with the field experience using a large field database
collected by the sponsors. In addition, progress in the understanding will be made in the areas of localized corrosion, hydrodynamics (droplet
transport and co-condensation), TLC in sour conditions, TLC inhibition techniques ... This will lead to the elaboration of a fully mechanistic predictive model, validated over the largest amount of field data ever collected, and merged into a operator friendly tool.
- Conduct a project to identify the effect of CO2, HAc and H2S on the TLC rate.
- Identify and model the different condensation regime involved in hydrocarbon/water mixture and the influence of the gas velocity on
- Study and model the localized corrosion mechanism at the top of the line.
- Quantify the effect of industrial volatile inhibitors on the corrosion rate.
- Develop a practical tool for TLC prediction enabling operational decision.
- An improved understanding of the phenomena of corrosion under dewing conditions.
- A predictive model for the risk of Top-Of-The Line Corrosion validated over field data.
- Selection of the volatile inhibitors that show a maximum efficiency regarding Top-Of-The Line Corrosion remediation.
The TLC JIP was initiated in July 2003 and is scheduled to end in February 2016.