Carbon capture and storage is a relatively new technology to store pressurized carbon dioxide underground. One of the challenges is to keep pipelines and injection tubes safe and prevent corrosion. Element supports corrosion testing of metallic components and examines polymeric materials to reduce transport costs and avoid failure.
With the increased concern of carbon dioxide (CO2) on the environment, reducing carbon emissions into the atmosphere is now a major focus for most industrialized countries. Reducing carbon emissions has led to carbon capture and storage (CCS), or carbon capture, utilization and storage (CCUS) projects. The projects have predominately been in the USA and Canada for Enhanced Oil Recovery (EOR), but there is a growing demand in Europe, Asia and the Middle East.
Numerous global projects in the planning stage are operational as pilot, research, and development plants in most countries where CO2 is produced. Most CCS/CCUS projects aim to capture CO2 and store it below the surface, mainly in offshore locations.
Corrosion of CCS transportation pipelines
For metals used in the CCS/CCUS infrastructure, the corrosion or cracking of the carbon steel transportation pipelines and carbon steel or corrosion resistant alloy (CRA) injection tubing is the primary concern of potentially corrosive environment.
The risk of corrosion/cracking needs to be evaluated on a case-by-case basis since it’s severity will depend on the material and the specific levels of H2O, O2 and acidic gas impurities of CO, H2S, SOx, and NOx in the dense phase CO2.
In order to mitigate carbon steel corrosion in CCS transport pipelines, the use of corrosion inhibitors can be considered. However, their effectiveness would be dependent on the specific conditions, so would require qualification testing.
Corrosion Testing for CCS infrastructure may be required to evaluate the resistance of the materials to:
- CO induced Stress Corrosion Cracking (SCC) of carbon steels (Transportation pipelines)
- H2S induced Sulfide Stress cracking (SSC) of carbon steels (Transportation pipelines)
- H2S induced Stress Corrosion Cracking of CRA’s (Injection tubing/casing)
- General corrosion of carbon steels (Transportation pipelines)
- Pitting corrosion of corrosion-resistant alloys-CRA’s (Injection tubing/casing)
Testing polymeric materials
The main concerns in the use of polymeric materials for seals, linings, etc. in the CCUS infrastructure are:
- the physical effects of the CO2 on those materials, for example swelling and weakening
- rapid gas decompression damage such as blistering, cracking, splitting
- chemical resistance to gas impurities - the influence of contaminants on the long term integrity of the materials
- the high pressure and low temperature operating conditions for CCUS can be a limiting factor to the use of some polymers
- loss of product or environmental issues caused by permeation of CO2 through polymeric seals and liners
The Element advantage
Our centers of excellence for the Energy sector are located in the US and Europe. The locations are fully equipped to perform corrosion testing and electrochemical testing on metallic components and polymeric materials used for CCS/CCUS infrastructure.
For more information about our corrosion testing services for CCS/CCUS, or request a quote, contact us today.
The principles of Carbon Capture and Storage
The primary sources of CO2 are coal and gas power plants, chemical plants (e.g., fertilizer production), oil refineries, and gas processing. In most CCS/CCUS projects, the CO2 is initially separated (captured), then compressed/processed and transported to the storage/usage location. The transported CO2 is either injected into existing producing oil wells for enhanced oil recovery (EOR) or injected into underground aquifers, salt caverns, porous rock formations, or depleted gas fields.
Compression/processing, transport, and injection operations must consider the impact of metallic componsents and the degradation of the polymeric materials.
For the corrosion of metals, the main factors to consider in the CO2 environment are water and gaseous impurities, in particular, O2, CO, H2S, SOx, and NOx. The processing of the CO2 is aimed at removing water and impurities; however, depending on the source of the CO2 low levels of water and impurities can remain in the transported gas. For transport and storage, to make the process economical, the CO2 is pressurized, which results in the CO2 gas phase being changed to a dense phase liquid or supercritical liquid. Any water within the dense phase CO2 will drop-out and will be acidic, with a pH of approximately 3, due to carbonic acid formation, from dissolved CO2. Other acidic species may also be present within the water phase resulting from the SOx and NOx impurities in particular.
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