Corrosion and flow assurance

Our objectives in research are firmly embedded in the use of the best of engineering science to solve challenging industrial problems.

Expertise

CO2 Corrosion (subcritical and supercritical)

The dissolution of carbon dioxide (CO2) in an aqueous phase can create an exceptionally corrosive environment. CO2 corrosion is one of the main sources of internal corrosion in the oil and gas industry but is also prevalent in geothermal systems and CO2 transport and injection infrastructure as part of Carbon Capture and Storage (CCS) processes.

In iFS we have a range of facilities available to study CO2 corrosion over a range of environments, including static, turbulent, single-phase, multiphase (sand/oil), ambient pressure to high pressure (supercritical) and ambient temperature to high temperature (300oC).

We also have the ability to conduct corrosion experiments in supercritical CO2 with trace amounts of natural and anthropogenic impurities (e.g. water, SOx, NOx, H2S and O2). 

H2S Corrosion

H2S corrosion is a significant problem encountered in the oil and gas and geothermal sectors. Low H2S concentrations are known to provide an inhibitive effect to carbon steel, whilst higher H2S content has been linked to localised corrosion.

One of the key challenges in H2S corrosion is understanding the development and transitions of differing iron sulphide (FeS) films and their relationship with the propensity for localised corrosion to occur.
iFS possess a unique H2S facility which has been expanding and evolving over the last 10 years. We are currently able to conduct H2S electrochemical experiments (with or without CO2) up to temperatures of 150oC, with this limit set to rise in the near future. Our H2S system is able to study corrosion in static or dynamic and is equipped for inhibitor injection.

Our H2S facility is supported by an in-house surface analysis facility for the in situ and ex situ characterisation of surface products.

Mineral scaling

Mineral scaling is a common issue in oil and gas, geothermal, and desalination processes.  iFS have expertise in numerous areas of mineral scaling and have experience with studying the nucleation and growth or deposition processes associated with carbonates, sulphates and sulphides. iFS possess several bespoke setups/test cells that enable us to monitor mineral deposition processes in situ to provide real time analysis of nucleation and growth/dissolution kinetics, these range from flow cells with in-situ visualisation, electrochemical, Raman and XRD capabilities.

Localised/pitting corrosion

Localised corrosion encompasses any degradation process whereby the local rate of material dissolution is significantly greater than the surrounding surface. Localised attack can be triggered by a number of different mechanisms and be related to one or a combination of environmental, physical, metallurgy and surface properties. iFS have a range of measurement techniques for understanding and observing the initiation and propagation of localised corrosion across length scales, both in situ (electrochemical noise, optical analysis) and ex-situ (non-contact profilometry, x-ray tomography). We have also devised several bespoke experimental setups to understand localised corrosion processes (in situ abrasion and pit pencil methods).

Under-deposit corrosion

The generation of thick deposits such as sand or corrosion products can result in local heterogeneity at the steel surface, restrict corrosion inhibitor transport, and create local environments that prevent the inhibitor from functioning efficiently. In iFS we have devised laboratory methods to measure the ability of inhibitors to arrest pit propagation in under-deposit environments, measure the local chemistry under deposits and within large artificial pits, and quantify inhibitor transport through deposit of all kinds. These combined methods enabling us to effectively screen and optimise inhibitors for performance in under-deposit environments.

Top of line corrosion

Top of line (TOL) corrosion in pipelines typically occurs during the transportation of wet gas, or in stratified flow regimes where a significant thermal gradient exists across the pipeline wall. This temperature gradient leads to the condensation of corrosive species, which can be particularly aggressive due to the presence of dissolved acid gases (CO2, H2S) and organic acids. iFS have bespoke laboratory equipment for the simulation of TOL processes. We are also able to measure corrosion rates in situ and in real-time using microelectrodes and/or electrical resistance probes, as well as collect and analyse the condensate.

Numerical modelling 

iFS have expertise in the development of mechanistic corrosion prediction and water chemistry models, predominantly for CO2 and H2S environments. We have models for the prediction of general CO2 corrosion in single phase flow and top of line environments and water chemistry prediction in CO2 and H2S. We are currently focused on the development of models for the prediction of corrosion product/mineral deposit growth, as well as oil-water wetting. We are able to develop codes and work across a multitude of different platforms, including Excel, Matlab, Python and COMSOL, depending on our collaborator’s requirements.

Acidizing corrosion

Strong, inhibited acids can be used for reservoir stimulation in the oil, gas and geothermal industry for restoring/increasing flow and/or productivity. Such acids are typically delivered through coiled tubing or directly down production lines, making chemical corrosion inhibition essential.

Over the last 5 years, iFS have developed extensive expertise in the corrosion of pipeline and coiled tubing materials across a range of strong acids, at temperatures in excess of 80¬°C. We have recently added a Tantalum-lined autoclave to our facilities, which enables us to extend our acidizing testing capabilities to even higher temperatures and more aggressive acid mixtures. We also have several unique test cells/systems for accurately quantifying acid corrosion inhibitor performance by avoiding issues such as acid spending and/or inhibitor aging in long duration experiments.

Mechanically-influenced corrosion

Mechanically-influenced corrosion encompasses any aspect where mechanical factors (e.g. stress, fatigue, erosion) occur in conjunction with corrosion, resulting in the deterioration and/or failure of materials. iFS possesses experience in the fields of stress-corrosion cracking, sulphide stress-corrosion cracking, cyclic corrosion fatigue and fretting corrosion and erosion-corrosion (solid particle impingement). Many of our experimental systems (e.g. flow loop, jet impingement rigs, fretting rigs) are configured such that we can monitor erosion and corrosion processes simultaneously in real time using a combination of acoustic and electrochemical measurements.

Corrosion in molten salt

Molten salts are currently widely used as heat storage materials and heat transfer fluids in CSP plants. They are also used as coolants and fuel source in next generation molten salt reactors (MSRs). Metallic components used in both CSPs and MSRs interacts with molten salts at extremely high temperatures (typically from 500 - 1000°C). Molten salt induced corrosion will likely affect the efficiency of these systems and the thermomechanical properties of materials used. The dissolution of materials, breakdown of corrosion oxide layers and selective leaching of alloying elements into the molten salt media will likely influence the thermal performance of these systems and heat exchanger architecture within the system. In iFS, we have recently invested in the infrastructure to be able to evaluate material performance and characterise their degradation mechanisms in molten salts (with and without in-situ electrochemistry).

Corrosion inhibitor optimisation and evaluation

Carbon steel remains one of the most popular construction materials for pipelines as a result of its favourable mechanical properties and low cost. Typically, the most cost-effective method for corrosion control of carbon steel is the application of corrosion inhibitors. These inhibitors are typically surfactant molecules which adsorb onto the steel surface, creating a dynamic physical barrier to protect the steel pipeline integrity. The performance of these inhibitors is paramount to the safe and reliable operation of carbon steel systems. In iFS we possess unique facilities and methods to understand and optimise inhibitors, from single component to multi-component formulations. We have a range of bespoke flow cells and analytical techniques to analyse inhibitor behaviour.

Corrosion in concrete

Concrete infrastructure forms the fabric of modern cities around the world. Professor Susan Bernal Lopez and her team in Civil Engineering are studying low-carbon cements, with the aim of developing sustainable cement alternatives which can be produced from wastes or by-products from different industrial, mining or agricultural processes. iFS are collaborating with Professor Bernal Lopez’s team in the School of Civil Engineering. Together we are working to provide new insights into how structural steels corrode when embedded in concretes that are produced with novel cements using a combination of methods, studying materials from the micro- to the nano-scale with an interdisciplinary focus. Our combined facilities include electrochemical sensors for deployment in concrete, as well as environmental chambers and state-of-the-art tomography analysis.

Flow-accelerated corrosion and two-phase (oil-water) flow

Flow-accelerated corrosion related to any process whereby the hydrodynamic characteristic of a fluid accentuates the level of degradation. Such effects can be observed across throughout the energy sector. iFS have a number of different setups to simulate fluid flow processes, from rotating cylinders to jet impingement and flow-loop. iFS can also 3D print bespoke fixtures/fitting that integrate into our flow loops. Finally, we have systems to create two-phase oil and water flow, as well as setups to control oil-water wetting precisely.

Corrosion and scaling mitigation techniques

iFS develop novel approaches to effectively mitigate corrosion and mineral scaling across a variety of environments. In the context of corrosion mitigation, we have developed novel technologies which revolve around the augmentation and/or functionalisation of corrosion products. We have also developed unique surfactants with the ability to work synergistically with corrosion products. In the context of mineral scaling, we have developed unique slippery liquid infused porous surfaces with excellent resistance to the precipitation of a wide range of minerals.

PhD projects

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Research team

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