CO₂ for building a more sustainable society 

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The list of processes in which this alleged foe turns out to be a friend is quite long, and that list is about to get longer thanks to carbon capture, use, and storage and direct air capture (CCUS and DAC).

CCUS technologies are designed to be integrated into industrial facilities or energy plants, while DAC directly absorbs the CO₂ from the air. Both capture this gas for subsequent storage or use and they both work in similar ways. “It's a three-phase process,” explained Jordi Pedrola, senior scientist at the Repsol Technology Lab specializing in CO₂ separation technologies. “The former is the separation of that CO₂ from the flow where it is generated,” he said. To do that it contacts that flow with an absorbent liquid that chemically traps it. Subsequently, applying heat to this fluid creates a more concentrated flow of CO₂.

“Finally, the CO₂ needs to be purified and compressed and then transported to its final destination,” Pedrola explained with regard to the second and third phases. The most exciting thing about carbon capture is not just that it helps remove it from the atmosphere, but that it also turns it into a clay that can be molded into any kind of product. To start, the industry can use it directly without having to process it, but CO₂ can also be treated and combined with other substances to create polymers, synthetic fuels, sustainable cement and concrete, etc.

The Spanish Association of Petroleum Product Operators (AOP) estimates that 40 different products can be made with the 40 million tonnes of CO₂ that the IEA projects will be captured around the world. The IEA groups these products into three categories.

Producing building materials is one of the most promising uses for captured CO₂, as it would help the sector move toward climate neutrality.

One of the ways to do that is by leveraging the CO₂ captured during the concrete curing stage. In other words, replacing the water normally used in the solidification and curing process of this building material.

There are three advantages here: using the CO₂ removed from the atmosphere, preventing consumption of a limited resource like water, and obtaining a cheaper concrete with an equivalent performance to conventional concrete.

Captured CO₂ synthesis with hydrogen is able to produce synthetic fuels and efuels with a low or zero carbon footprint. These fuels are the perfect solution to decarbonize propulsion systems for long-distance transportation such as ships, planes, trucks, etc.

In fact, if the energy used to create the chemical synthesis they are produced with is renewable, there is double the success: You remove CO₂ from the atmosphere, and you produce fuel with zero net emissions.

The carbon and oxygen in CO₂ can play the same role that oil products traditionally played in the chemical processes used to produce methanol and polymers. The former is a basic form of alcohol that can be used as a solvent, fuel, in the formulation of liquid coolant, and in the production of various chemical products, including formaldehyde.

The polymers obtained using captured CO₂ offer the advantage of a smaller carbon footprint as they replace a portion of the substance's fossil-based raw materials. These polymers can be used to produce the foam in mattresses, adhesives, coatings, and more... Everyday comforts made using the same carbon dioxide we need to remove from the atmosphere.

_{Published in El Mundo}