What is the Difference Between Carbon Capture and Sequestration

The main difference between carbon capture and sequestration is carbon capture is the initial step of trapping carbon dioxide emissions, while sequestration involves storing that captured carbon to prevent its contribution to the greenhouse effect.

Carbon capture and sequestration (CCS) is a tech solution to tackle climate change. It captures CO2 from factories and power plants, transporting it and storing it safely underground.

Key Areas Covered

1. What is Carbon Capture 
      – Definition, Features, Techniques
2. What is Carbon Sequestration
      – Definition, Features, Process 
3. Similarities Between Carbon Capture and Sequestration
      – Outline of Common Features
4. Difference Between Carbon Capture and Sequestration
      – Comparison of Key Differences
5. FAQ: Carbon Capture and Sequestration
      – Frequently Asked Questions

Key Terms

Carbon Capture, Carbon Sequestration

What is Carbon Capture

Carbon capture is a critical aspect of addressing the escalating levels of carbon dioxide (CO₂) in the atmosphere, a major contributor to climate change. The chemistry of carbon capture revolves around capturing CO₂ emissions from industrial processes, power plants, and other sources before they are released into the air. Several techniques, including absorption, adsorption, and chemical reaction, are used in this process. However, there are various challenges in carbon capture. Energy requirements, cost-effectiveness, and scalability are key considerations. Additionally, the captured CO₂ needs secure storage or utilization to prevent its release back into the atmosphere.

Techniques Used in Carbon Capture

One prominent method is amine-based absorption, where chemicals known as amines act as absorbents. These amines, typically liquid solutions, have a high affinity for CO₂ molecules. As flue gas containing CO₂ passes through a scrubber or absorber, the amines react with the CO₂, forming a stable compound. This process effectively separates CO2 from other gases in the flue gas stream. Subsequent heating of the amine- CO₂ compound releases the captured CO₂, and the regenerated amine solution is ready for another cycle of absorption.

Adsorption is another technique used in carbon capture, involving solid materials such as activated carbon or metal-organic frameworks. These materials have a large surface area and can adsorb CO₂ molecules onto their surfaces. Similar to absorption, the captured CO₂ is later released through heating, allowing the adsorbent material to be reused. This method is advantageous in certain applications due to its simplicity and potential for lower energy consumption.

Chemical reactions that directly convert CO₂ into stable compounds are also explored for carbon capture. Mineralization is one such approach, where CO₂ reacts with minerals like olivine or serpentine to form stable carbonates. This not only captures carbon but also results in a long-term storage solution. However, the challenge lies in the slow kinetics of these reactions, requiring optimization for practical application.

Innovative advancements in electrochemical methods offer a promising avenue for carbon capture. Electrochemical processes use electricity to drive reactions that capture and convert CO2 into valuable products. For instance, electrochemical reduction can transform CO2 into fuels or chemicals. This approach not only captures carbon but also provides an opportunity to store energy in the form of chemical products.

What is Carbon Sequestration

Carbon sequestration is a crucial mechanism in mitigating climate change. It involves capturing carbon dioxide from the atmosphere and storing it in long-term reservoirs. This process plays a vital role in reducing the concentration of greenhouse gases, thereby mitigating the adverse effects of global warming. Natural systems, such as forests and oceans, act as carbon sinks, sequestering carbon through photosynthesis or absorption.

In addition to natural processes, technological advancements have led to the development of carbon capture and storage (CCS) techniques. These technologies aim to capture CO₂ emissions produced from industrial processes and power generation before they are released into the atmosphere. The captured carbon can then be transported and stored underground in geological formations, preventing its contribution to the greenhouse effect.

Similarities Between Carbon Capture and Sequestration

• Both involve capturing CO₂ emissions from sources like industrial facilities or power plants and preventing them from entering the air.
• Their goal is to reduce greenhouse gas emissions and help combat global warming.

Difference Between Carbon Capture and Sequestration

Definition

Carbon capture is the process of capturing carbon dioxide emissions produced from industrial processes or power generation, while carbon sequestration is the storage of captured carbon dioxide in a long-term reservoir, preventing its release into the atmosphere.

Process

Carbon capture occurs at the source of CO₂ emissions, such as power plants or industrial facilities, while carbon sequestration involves storing the captured carbon in geological formations, like underground rock formations or depleted oil and gas fields.

Timing

Moreover, carbon capture is the initial step in the process, focusing on the capture and separation of CO2 from industrial processes, while carbon sequestration comes after carbon capture and involves the secure, long-term storage of the captured carbon dioxide.

FAQ: Carbon Capture and Sequestration

What are the 3 methods of carbon capture?

Post-combustion carbon capture (the primary method used in existing power plants), pre-combustion carbon capture (largely used in industrial processes), and oxy-fuel combustion.

What is an example of carbon capture?

Coal gasification is an example where carbon capture is used.

Can carbon capture stop climate change?

Carbon capture cannot entirely stop climate change, but it can contribute significantly to reducing greenhouse gas emissions. 

Conclusion

The main difference between carbon capture and sequestration is carbon capture is the initial step of trapping carbon dioxide emissions, while carbon sequestration involves storing that captured carbon to prevent its contribution to the greenhouse effect.

Reference:

1. “What is Carbon Capture and Storage?” Climate Council.
2. “What is carbon sequestration?” USGS.

Image Courtesy:

1. “Carbon capture and storage” By KevinMShea – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Carbon sequestration-2009-10-07” By LeJean Hardin and Jamie Paynederivative work: Jarl Arntzen (talk) – ORNL  (CC BY-SA 3.0) via Commons Wikimedia