Carbon capture technology refers to technology used to capture and store CO₂ before it is released into the atmosphere, thereby reducing carbon emissions.

The concept of carbon capture and Underground storage (CCUS) has been around since the 1970s and was more commonly known as enhanced oil recovery with miscible floods, although at that time the focus was on increasing oil yield rather than emission reduction targets.

More recently, CCUS is also touted by the energy industry as a potentially viable means of reducing overall system emissions.

Below we’ll discuss various aspects of CCUS and related concepts.

Why does carbon capture technology exist?

CCUS exists due to the realization that there aren’t currently enough green energy resources to fully replace fossil fuels globally. Because of our need to continue using fossil fuels, it therefore makes sense to investigate how to make the overall system emit as few greenhouse gas as possible. As CO₂ is one of the products of hydrocarbon combustion and CO₂ is one of the measures international bodies have identified as a source of global warming, attention is focused on mitigating CO₂ emissions.

CCUS may prove to be a viable means to help reduce these emissions.

Many of the emissions produced in Alberta tend to be clustered, providing an opportunity for capture and storage

In 2017, it was estimated that many emissions come from the oil & gas industry in the form of unburned hydrocarbons, and around 40% of that comes from Alberta alone. Although much was accomplished since 2017, there is still work to be done.

Mitigating these unburned hydrocarbon emissions is addressed by Canada’s energy industry with a combination of measures on the Instruments and Controls (I&C) side, a small but nevertheless meaningful emissions source. Further work is needed on larger scale emitting systems.

CCUS offers a path, and the Pathways Alliance, a joint effort between Canadian Natural, Cenovus, ConocoPhillips, Imperial and Suncor, five of Canada’s largest oil sands companies work together to advance this technology. The Pathways CO₂, Transportation Network and Storage Hub aims to transport and store captured CO₂ from multiple oil sands facilities in NE Alberta. Filings of regulatory submissions commenced in Q1 2024. The proposed Pathways CO₂ Transportation Network begins at the boundary of each oil sands facility and move through pipelines to the Storage Hub, where it will be stored between 1 and 2 km below the surface in a suitable location.

Transportation is intended to take place through 16 Pathways Laterals ranging from 8 to 20″ dia. with lengths varying between 1-49 km. The Pathways Transportation line will be 16-30″ to connect laterals to the Hub Distribution Line, on to the Pathways Storage Hub at ~330 km in length.

Carbon capture and storage consists of 3 processes

CCUS fundamentally consists of three processes:

Capture – Capturing the emissions pre-combustion and post-combustion depending on the situation.

Transport – Transporting the emissions to their storage location.

Underground Storage – Typically the storage of emissions are injected into suitable formations

Carbon capture technology advantages

Carbon capture and storage technologies can offer a number of advantages:

• Removes CO2 at the source.
• Reduces emissions at the source.
• Reduces other contaminants at the same time.
• Reduce the social cost of carbon.

A more detailed explanation of each advantage along with potential considerations is outlined in this article.

Below is a short video from Shell explaining visually how carbon capture and storage works.

How can OilPro assist CCUS projects with Innopipe?

Our Innopipe system can ensure corrosive liquids and their entrained contaminants formation are minimized.

About CO₂ lines and common contaminants

Specifications for transportation lines are hydrocarbon industry application derived. Early CO2 pipeline operations are finding the hydrocarbon industry derived specifications are not always suitable for CO₂ transportation where pH values differ and impurities act differently than decades of hydrocarbon transport predicted. For example the curves hydrocarbon professionals use to guide their decision making, such as partial pressure curves go out the window with dense CO₂.  ISO15156 standards do not account for pH of the water phase in pure dense CO₂ and are outside of experience and empirical data sets used to derive the standard. Additional impurities such as HCN, H₂ may lead to increased stress crack formation. 

Innopipe systems can be adapted to standards required by Integrity Management teams to provide CO₂ pipelines a reasonable service life. The accumulations of impurities in the wrong locations often cause the greatest troubles. Removing the impurities before they cause catastrophic failures is expected to mitigate risk factors caused by unanticipated mechanisms of interaction which might not have been flagged versus when contaminants were looked at in isolation. 

While CO₂ captured  from natural gas is often called “pure”, the real world sees H₂O, CH₄, N₂, H₂S, O₂ and other trace contaminants suchl as sources of post-combustion processes such as NO_x and SO_x and also sorbent chemicals in the spec mix,

Water soluble carbonic acids and their effects on pH lead to extensive corrosion, especially when systems are operated outside of an ideal operating window from a transportation point of view. This ideal window occurs where CO₂ is in a supercritical state around ~70 bar, 30°C where P&T>Tc, in which case it has the density of a liquid but viscosity of a gas, which is ideal for transport. To make this topic more relatable, (and learn how it is used daily to decaffeinate coffee) look no further than this video, “the Unknown Phase of Matter” by Steve Mould.

When a pipeline system has locations where real-world impure CO₂ gas is not inside this ideal critical state window, an Innopipe may be considered for liquids removal to mitigate unpredictable interactions.

Contaminants and impurities cause Vapour Liquid Equilibrium Lines to shift to a wider dual phase CO₂ gas-liquid domain with variations in critical pressure and temperatures.

Althought CO₂ is a stable, inert and non-corrosive gas, upon dissolution in water and subsequent hydration it forms a weak carbonic acid (H₂CO₃). Carbonic Acid dissociation is a leading cause of steel oxidation, per this formula: H2CO3(aq) -> HCO^–_3(aq) + H⁺_(aq).

Water

In the gas phase, water solubility is critical. While acceptable water limits trend in the 300-500 ppm wt range, colder Canadian conditions often save us, but in warmer parts of the world or during warmer periods, pipeline design conditions of 5C put may such pipelines in critically exposed conditions, often exacerbated by water solubility reducing contaminants such as nitrogen and methane, perhaps sometimes offset by negligible or counterintuitively beneficial contaminants such as oxygen, glycol and H₂S.

Simply put, to prevent corrosion; prevent water accumulation.

Design Practices

Pipeline codes tend to be written with hydrocarbon transport in mind. CO₂ requires a different approach. We look forward to working with your team to find optimized solutions in this dynamic field. Innopipe may provide solutions.

Let us assist in discovering how to build for the real world where contaminants exist.  Ask us to assist with pre-FEED and other front end engineering and design questions. Like many pipeline integrity managers, we may not have all the answers, but we’ll do our best to treat your questions in a forthright manner, and look forward to working on solutions together.

You can also give us a call at 403 215 3373 or email us at [email protected] and we’ll be happy to discuss your needs.