While the world continues to emit carbon dioxide and the earth continues to warm, it has become imperative to discuss not only ways to reduce pollution in the future but also to get rid of the emissions already present in the air.
While most countries’ primary focus is to curb greenhouse gas emissions, we cannot ignore that climate change has already begun and has already caused significant damage and disruption. Therefore, a new process is being developed to help reduce emissions released, and this process is what we call carbon capture.
Carbon dioxide is essential for the earth; it is a greenhouse gas that is naturally present in the atmosphere. This greenhouse gas traps the heat, plays a role in weathering of rocks, and is an essential source of carbon dioxide for plants for the process of photosynthesis. The fact that is usually ignored or forgotten is that carbon dioxide is naturally present in abundance in the atmosphere. The overabundance of carbon dioxide will lead to too much heat being trapped, which is precisely what is happening right now. Human activities cause more release of carbon dioxide than the carbon cycle can handle. Researchers hope that carbon capture technology can help remove some of these emissions from the atmosphere.
Carbon capture has no clear definition yet because multiple methods are being explored. Still, it could be defined as a process that involves capturing waste carbon dioxide from the atmosphere and storing it not to let it enter the atmosphere again. Some carbon charging types focus on emitting sources and look for ways to filter out the carbon from the production plants themselves, whereas the other type tries filtering out the CO2 from the air. Once the carbon is captured using either two methods, there are then two options, one is to store it in a way it can never pollute again, or the other is to put it to some good use. If it is decided to put the carbon dioxide to use, some things it can be used for are carbonated drinks or growing plants.
Usually carbon dioxide is already present in so much abundance, there is no demand for captured carbon; therefore, most people focus on sequestration, which is storage. The most common way to store carbon is to pump it deep into the earth in reservoirs; this way, the carbon dioxide will not be released into the atmosphere for a very long time.
One crucial term is CCUS, which stands for Carbon Capture, Utilisation, and Storage when talking about carbon-capturing. It is used as a designator for any projects that use carbon capture technology. You will find several CCUS projects, but there are only 50 commercially working projects, and that is because the technology has just been implemented. But these projects are currently a necessity, and estimates show that if the carbon capture technology is appropriately implemented, it can reduce pollution caused by carbon emissions by one-fifth and the cost spent on climate change by 70%.
The core technologies of the carbon capture technology are not all that new; they have been used to help make the recovery of old and gas more efficient.
There are three main areas that scientists and engineers have focused on when talking about capturing and sequestering carbon dioxide. They are:
- They trap it and separate it from other gases
- Transport it to the storage location
- Store it
The first step is the capturing, and the separation is where the central part of the innovation of this technology occurs. Now, carbon can be captured in many ways, as said before. Carbon can be captured either before, during, or after the carbon-fuel is burned. One other place carbon can be captured from is fossil fuel plants because they focus on generating heat using carbon-intensive fuels. One method for post-combustion carbon capture is using a filter containing a solvent that, upon heating after absorbing the carbon dioxide from the waste gases, will leave behind a concentrated carbon dioxide steam. This method is the most effective because it removes 90%of the CO2, but it is also the most expensive because the carbon dioxide is obtained in a gas form that has to be then compressed to be shipped and then sequestered.
In the burning of fossil fuels, particular protocols are followed which separate carbon emissions; this occurs in the pre-combustions phase where carbon can be captured. Burning fossil fuels produce a mixture of carbon monoxide and hydrogen gas because they are usually burned in a pure oxygen atmosphere. The two waste gases are then made to flow through a catalytic converter which converts these gases into carbon dioxide and hydrogen gas. After the conversion, a chemical is added to the mixture to bind the carbon dioxide; this chemical is called an amine. The chemical product is then called amine-CO2, which settles at the tank’s bottom, leaving the hydrogen gas on the top. The hydrogen gas is then piped out, and the amine-mixture is heated. Upon heating the mixture, the carbon dioxide separates and rises to the top for extraction. When this method is appropriately implemented, it can extract up to 90% carbon dioxide and is relatively cheaper.
There is also another method called oxyfuel carbon capture. This method is relatively simple. The fossil fuel is again burned in the presence of oxygen, which creates a steam and carbon dioxide gas mixture, and when this mixture is cooled, the steam condenses, and the CO2 remains gaseous and is then extracted.
Other than in-plant carbon capture, other methods such as filters push air through basaltic minerals. When this is done, it binds CO2 into a mineral-CO2 slurry which is then pumped into the earth for storage. As seen in most cases, the captured carbon dioxide is pumped into the earth because it prevents pollution, which is the main aim.
The pumping of carbon from these gases and compounds brings about the carbon complete cycle. This means that initially, from where it was pumped out by oil companies and burned, it is now being returned after CCUS projects’ capture.
Another surprising fact about carbon capture is that it is not always pumped into the ground; companies also use it to produce beer and chips. For example, the chips company Walkers partnered with a British brewery to capture the CO2 from the fermentation process.
Lastly, it has been said that these carbon capture projects are bringing the world some hope about the future of this earth’s atmosphere.