How does Carbon Capture & Storage work?

Summary

The video script addresses the urgency of tackling climate change by focusing on the role of the Australian coal industry and its commitment to investing in carbon capture and storage (CCS). It outlines three key methods of CCS: pre-combustion capture, which involves converting coal and oxygen into a gas that releases CO2 for capture; post-combustion capture, where an absorber column captures CO2 from flue gas; and the oxy-fuel process, which separates nitrogen from oxygen to create a CO2-rich environment for capture. The captured CO2 is compressed into a liquid and stored deep underground in porous rock formations, a process known as geo-sequestration. The script emphasizes the stability of stored CO2 and the natural processes that can further stabilize it over time. It concludes by highlighting the importance of integrating CCS into new and existing power plants as a critical solution to climate change.

Takeaways

• 🌍 **Climate Change Impact**: Human activities such as land clearing, intensive farming, and burning fossil fuels contribute significantly to climate change by producing greenhouse gases.
• 📉 **Reduction of Greenhouse Gases**: There is a need to reduce greenhouse gases, particularly carbon dioxide (CO2), to slow down and reverse global warming.
• 💰 **Investment in Carbon Capture**: The Australian coal industry is investing a billion dollars in carbon capture and storage technologies to play a role in climate change solutions.
• 🔬 **Carbon Capture Methods**: There are hundreds of active carbon capture and storage projects worldwide, utilizing methods like pre-combustion capture, post-combustion capture, and oxy-fuel combustion.
• ⚙️ **Pre-Combustion Capture Process**: In pre-combustion capture, coal reacts with oxygen to form a gas, which is then treated with water to produce CO2 and hydrogen, with CO2 being captured for storage.
• 🔥 **Post-Combustion Capture Process**: Post-combustion capture involves burning fossil fuels and using an absorber column filled with solvents to capture CO2 before it is released into the atmosphere.
• 🌬️ **Oxy-Fuel Combustion Process**: The oxy-fuel process removes nitrogen from oxygen, resulting in a more concentrated CO2 output that can be captured after the combustion of fossil fuels.
• 🧪 **CO2 Classification and Storage**: Captured CO2 is inert and stable, similar to many naturally occurring gases, and is compressed into a liquid for transportation to a storage site.
• 🚛 **Transportation of CO2**: Liquid CO2 is transported via trucks or pipelines to suitable storage sites, with the U.S. having extensive pipeline networks for CO2 transportation.
• 🏞️ **Geo-Sequestration**: CO2 is stored in deep underground porous rock formations, with an impermeable layer acting as a seal to prevent CO2 from escaping into the atmosphere.
• 🔒 **Monitoring and Safety**: A sophisticated monitoring system tracks stored CO2 at three levels: subsurface, soil, and atmosphere, ensuring the safety and effectiveness of storage.
• 🌟 **Integration Challenge**: The challenge lies in creating a fully integrated system for carbon capture and storage that can be incorporated into new and existing power plants.
• 🌐 **Global Progress**: Successful carbon capture and storage projects are underway globally and are considered a critical part of the solution to climate change.

Q & A

What are the main human activities contributing to climate change as mentioned in the transcript?

The main human activities contributing to climate change mentioned in the transcript include land clearing, intensive farming, burning of fossil fuels like oil, natural gas, and coal, all of which produce greenhouse gases.

What is the role of the Australian coal industry in addressing climate change?

The Australian coal industry acknowledges its role in climate change and is investing a billion dollars in carbon capture and storage technologies to play a part in climate change solutions.

How does pre-combustion capture work in carbon capture technology?

In pre-combustion capture, coal is combined with oxygen to create a gas consisting of carbon monoxide and hydrogen. Adding water to this gas triggers a reaction that converts carbon monoxide into hydrogen and CO2. The CO2 can then be safely captured, while the hydrogen is used for energy production.

What is the process of post-combustion capture?

Post-combustion capture involves burning fossil fuel as normal, but before the flue gas travels up the chimney, it passes through an absorber column filled with liquid solvents called amines, which absorb the CO2. Superheated steam then releases the CO2 from the amines, allowing it to be captured safely.

How does the oxy fuel process differ from other carbon capture methods?

The oxy fuel process begins by stripping nitrogen from oxygen in an air separator, leaving behind purified oxygen. This oxygen is then used for combustion with a fossil fuel, producing CO2 and water vapor. The CO2 can be captured after the water vapor is condensed and removed.

What are the properties of the captured CO2 that make it suitable for storage?

The captured CO2 is classified as inert, meaning it is very stable like many naturally occurring gases, making it suitable for safe and permanent storage.

How is the liquid CO2 transported to its storage site?

The liquid CO2 is transported to its storage site using trucks if the site is close by, or through pipelines for longer distances or larger volumes. In the US, there are pipelines stretching thousands of kilometers used for CO2 transport.

What is geo-sequestration and why is it important for carbon storage?

Geo-sequestration is the process of storing CO2 safely and permanently in deep underground rock formations. It is important because it isolates the CO2 from the Earth's atmosphere, preventing it from contributing to climate change.

How are storage sites for CO2 chosen for geo-sequestration?

Storage sites are carefully chosen based on the presence of vast stores of porous rock deep underground. This porous rock acts like a sponge, filled with microscopic holes that can hold the injected liquid CO2.

What is the role of the impermeable layer above the porous rock in geo-sequestration?

The impermeable layer above the porous rock acts as a cap, preventing the liquid CO2 from escaping. It is non-porous, meaning it has no tiny holes for the CO2 to pass through.

How does the long-term storage of CO2 in geo-sequestration sites work?

Over time, the stored CO2 can be dissolved in salty non-drinking water or react chemically with the surrounding rock to form stable carbonate minerals, effectively sequestering the carbon.

What monitoring systems are in place to ensure the safety of stored CO2?

A sophisticated monitoring system is in place that operates on three levels: the subsurface, the soil, and the atmosphere around the site. This ensures the continuous safety and effectiveness of the CO2 storage.

What is the current status of carbon capture and storage projects worldwide?

Successful carbon capture and storage projects are underway globally and are considered a critical part of the solution to climate change. Their progress can be followed on platforms dedicated to new generation coal technologies.