The CCS Process

In the most common carbon capture process, impurities are first removed from the flue gas, and then the gas is passed through an absorption column filled with chemical scrubbing solvent. This solvent is the most commonly aqueous solution of monoethanolamine (MEA), though other chemicals can also be used, and new chemicals are constantly being researched. The chemical reacts reversibly with CO₂, capturing it from the flue gas. CO₂ can then be released by reversing the reaction, which usually happens by heating.

There are also other possible processes. Instead of burning, the fuel may be turned into CO₂ and hydrogen gas. After separating CO₂, hydrogen can be used as a clean fuel, forming only water when burned. Hydrogen produced this way with CCS is called blue hydrogen. Another possibility is burning the fuel with oxygen instead of air, leading to the flue gases being mainly CO₂ and water. As for the capturing itself, chemical absorption is also not the only possibility. There are also other methods, such as membranes, which can be created to be selective for a certain gas. Due to their modularity, they can be especially useful in far-away regions, e.g., at sea.

CO₂ utilization and storage

The captured CO₂ can be either stored indefinitely or used in a way that effectively stores it or otherwise negates other emissions. Usage of captured CO₂ can be especially relevant in locations where potential storage sites are far.

These days’ main storage option is deep underground, where the conditions cause CO₂ to behave more like liquid and only take a fraction of the volume it takes on the ground level. CO₂ is pumped to rock formations covered by a layer of caprock with very low to nonexistent permeability, which will prevent CO₂ from rising back to ground level. This is also the end state of enhanced oil recovery (EOR), a process where CO₂ is used to increase the amount of oil collected from an oil field. Another combination of usage and storage is reacting CO₂ with metal oxides to create carbonates. Carbonates are stable minerals that can be stored safely or used in construction.

CO₂ can also be used in ways that don’t store it. Using CO₂ and hydrogen gas (H₂), synthetic fuel can be created to be burned or components to be used in the chemical industry without using fossil fuels. Another potential use is in horticulture, where CO₂ may be used to enhance plant growth.

• Gasmet’s TÜV and MCERTS-certified Continuous Emission Monitoring System, the CEMS II e,  is prepared to measure CO₂, amines, and other potential CCS-related components such as ammonia, which can be an indication of MEA degradation. The FTIR gas analysis enables plant owners to monitor CO₂ levels in addition to almost any other gas from our library of over 400 compounds.
• For CCS research, Gasmet offers a portable GT6000 Mobilis and a continuous emission monitoring system, the CEMS II e.
• FTIR combined with our vast gas library means that our customers are well equipped to handle potential unknown gases, which is an especially useful feature in CCS research. It is possible to change or add the measured components after installation without any hardware change, making process changes easy to accommodate.

• Our software Calcmet can be used to save sample spectra, identify unknown components and reanalyze the sample spectra later to find the concentrations of these previously unknown components. You can read about our devices in CCS R&D here: Global industry leaders unify their technologies & expertise to lower carbon emissions.
• For storage site testing, Gasmet has GT5000 Terra and DX4015. These can be used to measure the soil flux of CO₂ and other greenhouse gases. Gathering solid background data of the CO₂ flux of a potential storage site could help in monitoring the site for potential CO₂ leaks.