How to Capture and Transport Carbon

Carbon is a natural gas that creates the greenhouse effect, which warms the earth. However, excessive amounts of Carbon Dioxide, produced by burning fossil fuels, can become trapped in the atmosphere. The largest stationary sources of CO₂ are power plants, where research efforts are focused on carbon capture systems. At this point, the process has been deemed possible, but is very costly. Here are the general steps for capturing carbon.

Step One:
Extract the carbon. The first step in the overall process is to remove the carbon from the source using post-combustion. Post-combustion is a method than can be used by conventional coal-fired power generation or combustion turbines fired by natural gas. The CO₂ is captured from flue gases which are a result of burning fossil fuel. Flue gases are a combination of CO₂, water vapor, sulfur dioxides, and nitrogen oxides. CO₂ is separated from this mixture using a filter that helps trap the CO₂ as it exits through a smokestack. This method is well-known and can be used in older power plants.

Step Two:
Transport the carbon to a storage site. Small amounts of CO₂ are currently transported using a pipeline. Usually a CO₂ pipeline begins at the power plant, where the CO₂ is captured. It travels to the storage site or to a transition point like a tanker or ship, where it is then carried to storage. CO₂ is most often transported in a gaseous state, with a compressor that forces the gas through the pipeline.

Step Three:
Store the carbon. Currently there are two places that can effectively store CO₂, underground and underwater. Underground storage (geological sequestration) allows CO₂ to behave like a liquid because of the pressure. The liquid then seeps into porous rocks or volcanic rocks below the Earth’s surface. Experts say that CO₂ can also be stored in the ocean, simply by dumping it directly into the water at a depth of at least 3500 meters. The CO₂ compresses into a slush and falls to the ocean floor. This method of storage is largely untested; it may harm marine life and could re-enter the environment.

Additional Information:
CO₂ capture has been successfully practiced for many years in the petroleum, chemical, and power industries for various reasons. However, only a small portion is being captured.

Although the successful capture of carbon is realistic, researchers must find a cost-effective way to transport and store the CO₂ before companies can move forward with capture.

Carbon capture can prevent 80-90% of a power plant’s emissions from entering the atmosphere.