Carbon Capture concept is to seize gases responsible of the greenhouse effect, preventing their increasing impact in our atmosphere.
From all the gases responsible of the global warming, Carbon Monoxide (CO) and Carbon Dioxide (CO2) stand on the top of the root causes, justifying to develop solutions for Carbon Capture.
Carbon Capture can occur in two situations, directly from the air, or from industrial processes. It is in this second case Carbon Capture is the most efficient by reducing up to 90% of CO2 emissions from a plant.
Carbon Capture can apply to all the activities producing CO2, with a priority given to the processes contributing for the largest amount of emissions.
Typically, the field of Carbon Capture refers to the following applications:
- Power Generation (wood, coal, oil, gas)
- Cement and Concrete plant
- Steel mill
- Fertilizer and Petrochemical complex
For all these processes, Carbon Capture requires the emissions to be cleaned from steam, nitrogen and sour gases to retain only the CO2 usually representing only 20% of the blend.
In power generation, the Carbon Capture can be implemented at different stages of the process. Three different types of Carbon Capture concept exist depending on their phase in respect with the fuel combustion:
The aim is to remove the carbon before the fuel is burnt. In practice, Coal for example can be baked with Oxygen to make a syngas of Carbon Monoxide (CO) and Hydrogen (H2). Hydrogen is then used as the fuel gas, while the monoxide is recombined with steam to create Carbon Dioxide (CO2) and additional Hydrogen (H2). For coal, the Pre-Combustion process can capture around 65% of the CO2 produced.
The aim is, instead of separating Dioxyde (CO2) from other gases, to generate output smoke of almost pure CO2. To do so, extra Oxygen (O2) is injected in the combustion to only produce steam and CO2 at the exhaustion. Once the steam easily removed, the output gas is made for around 90% of pure CO2.
Post-Combustion is the only of the three that can be retrofitted to existing plants. In fact, the aim is to remove the Carbon Dioxide (CO2) from the flue gases after the fuel is burnt, right before the CO2 is released in the air. The Post-Combustion filtering can half up to 90% of the produced CO2.
The technologies behind the Carbon Dioxyde (CO2) separation are many but three dominant streams are existing today at large scales:
- Amine absorption
Commonly used in the downstream to remove sour gas, amines and most specifically the MonoEthanolAmine (MEA) is able to capture as a solvent up to 85% of the under-pressure CO2.
The reaction is costly but efficient to transfer the CO2 in the liquid phase, even when the CO2 concentration is low.
- Ammonia absorption
The Ammonia (NH3) absorption is the process requiring more maturity but in which the CO2 capture is carried out at low temperature. The CO2 in contact with the liquid Ammonia will precipitate into the molecule of NH3–CO2–H2O, easily manageable because of its solid state.
- Membrane separation
Synthetic membranes, polymers or nano-materials, can filter Carbon Dioxide (CO2) from other gases because of their permeability. Membranes play the role of barriers through which gases move differently according to their size, solubility and diffusivity. Passing through series of membranes, flue gases can be separated by up to 90% of the CO2.
The last aspect of the Carbon Capture technology is of course economical. The Carbon Capture has a price which represents approximately 40% of the energy cost with the current technologies.
Anyway, the Carbon Capture is a must–needed solution to prevent global warming.
Since 2019, governments around the world are supporting more and more Carbon Capture projects in order to decrease their carbon footprints.
And of course, you can count on Project Smart Explorer to guide you on these projects: www.projectsmartexplorer.com
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