Driving decarbonisation efforts with pipeline simulation

The Australian Pipeliner spoke with Atmos International Senior Simulation Consultant John Anderton about Atmos SIM and how it helps pipeline operators in their decarbonisation efforts.

John Anderton has spent over 25 years working with pipeline simulation in varying roles from project delivery to product management, including two years working for a major gas transportation company in Australia as a business analyst. 

He specialises in offline and online simulation for the oil and gas industry and has worked with many major operators worldwide.

What is the state of Australia’s decarbonisation?

As one of the world’s largest liquefied natural gas (LNG) exporters, Australia has recently reevaluated its long-term strategy for gas production to place an emphasis on decarbonisation.¹

Decarbonisation is high on world leaders’ agendas, with nations at the recent COP27 collectively agreeing to meet net zero emissions and the removal of carbon from the atmosphere. Similarly, Australia’s ambition is to increase clean energy exports and support the energy transition.²

Once produced, hydrogen (H2) can either be burnt directly or mixed with oxygen to create fuel, with the only waste produced by hydrogen being water³.

Hydrogen will play a vital role in the energy transition through its versatility as an energy source for industry, transport, grid firming, chemicals, and metal production. As well, the versatility of hydrogen’s different production methods makes it a desirable alternative way for producing energy.

Colour descriptions are used to distinguish between hydrogen’s different production methods, with brown hydrogen emitting the most greenhouse emissions and green hydrogen emitting the least (see Figure 1).

Australia recently invested two billion dollars in the scale up of large green hydrogen⁴ as part of its campaign to be a global hydrogen leader by 2030². The region is also investigating in carbon capture, use and storage (CCUS), to support its decarbonisation goals.

Is CO2 a viable option?

In Australia’s Future Gas Strategy consultation paper, which dictates objectives such as 43 per cent emissions reductions on 2005 levels by 2030, the Australian government presents carbon dioxide (CO₂) as a viable alternative to fossil fuels in contexts like biogas for feedstock applications.

The region plans to introduce CO₂ as part of their decarbonization efforts, but the document acknowledges that there will be three requirements to achieve net zero by 2050:

•  Carbon capture and storage (CCS).

• 
A reduction in leaks, venting, flaring and fuel gas use.

•  Efficiency and demand management. ⁵

Pipelines will be vital in the transportation of hydrogen and carbon dioxide as Australia pursues its decarbonisation goals, but there are key factors to consider, which pipeline simulation software like Atmos SIM can help.

What key factors should be considered?

Introducing CO₂ and H2 to existing gas pipeline infrastructure has its challenges. For example, many materials aren’t suited for CO2 service and H2 requires pipeline infrastructure with little to no defects.

Pipelines transporting hydrogen and hydrogen blends run the risk of hydrogen embrittlement damaging the microstructure of the pipes themselves and causing cracks that escalate into leaks, so work is currently underway to repurpose natural gas pipelines in advance of the hydrogen economy⁶.

Atmos SIM can be used offline to test operational strategies prior to implementation.

Using a model which includes details of pipe material such as elastic modulus (𝑌), density (𝜌) and thermal connectivity (𝜆),⁷ Atmos SIM can determine, for example, whether the maximum velocity has been reached (typically 5-12 m/s in natural gas pipelines) which is when carbon dioxide corrosion becomes untenable.⁸

Used online and connected to a SCADA system, Atmos SIM can generate these calculations based on current or future-planned operations providing a powerful decision support tool for the control room to ensure the pipeline is operated safely and efficiently.

What about safety?

The safety of personnel, the public and the environment should take priority with the introduction of fuels like CO₂ and H2.

CO₂ is one of the most damaging greenhouse gases and can be an asphyxiant in high concentrations, posing an increased risk to human life.

Similarly, hydrogen can indirectly cause emissions when it reacts with molecules in the atmosphere. Pipeline simulation software can ensure the pipeline operation remains within allowable limits.

Optimisation features available in Atmos SIM can ensure gas pipeline operators working with CO₂ or H2 continue to work within their stringent maximum allowable operating pressure (MAOP) and lowest allowable operating pressure (LAOP) limits.

Simulation software can achieve this by making recommendations that reduce risk and secure safe operations, all while meeting customer demands.

Can you expand on leakage reduction?

Because CO₂ in CCS is often handled as a supercritical phase fluid (sCO₂) at high pressure, more gas would be released in the event of a leak, at a faster rate and a higher explosive decompression⁹.

Likewise, there are concerns that H2 can permeate metal and leak through the pipeline. H2 is flammable once released into the atmosphere too, its flame is almost invisible while still having a flammability that ranges between 4 per cent and 75 per cent¹⁰.

Quick and accurate leak detection is crucial for pipelines transporting CO₂ or H2.

Paired with hardware instrumentation, Atmos SIM’s leak detection module can continuously calculate volume balance on a gas pipeline.

Atmos SIM also monitors the discrepancies between measured and calculated pressures and flows. These discrepancies are processed by the sequential probability ratio test to generate reliable leak alarms to reduce leakage, venting and flaring.

How can operators drive decarbonsation with ATMOS SIM?

For Australian gas pipeline companies to successfully deliver on the decarbonisation strategy set by the government, pipeline simulation will be a vital element in the rollout of carbon capture and storage, the push towards safety, efficiency, and leakage reduction.

For more information visit www.atmosi.com/en/solutions/simulation.