Reducing carbon dioxide emissions

Greenhouse gas emissions have been consistently rising globally, and they are a driving force behind climate change. Most of the emitted carbon dioxide (CO2), the most prominent greenhouse gas, is from the fuel being burned to create power, but also some industries emit CO2 as part of their processes.

While a large portion of the emissions can be negated one way or another, for example, using renewable or nuclear energy to create power, another option is to deal with the emissions before they are released into the atmosphere. Carbon Capture, Utilization and Storage (CCUS, or simply CCS) is such a method. Instead of releasing CO2, it is captured within the process and either utilized in some way or stored safely.

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 solutions for CCS

Monitoring of emissions is required to ensure that the CO2 capturing is working correctly at the plant. Gasmet manufactures gas analyzers and emission monitoring systems based on the FTIR technique to measure gaseous emissions from industrial processes.

  • 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 DX4000 and the 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.

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