By Ansys Advantage Staff
![](https://fluidcodes.ir/wp-content/uploads/2023/01/climeworks-main-image-1.jpg)
Climeworks-captured CO2 turned into stone with the Carbfix process. Carbfix developed a process that captures CO2 and other acid gases in water, then injects this water into the subsurface where the gases are stored as stable minerals. Credit Carbfix. Photo by Sandra O Snaebjornsdottir
Climeworks’ direct air capture technology combined with the storage process developed by the Icelandic company Carbfix removes carbon dioxide from the air and stores it permanently underground. Image copyright Climeworks.
Designing Small and Scalable, For Big Results
The concept of carbon capture and sequestration isn’t new. In fact, it dates to the 1970s. The technology behind some methods goes back even further, all the way to the 1920s when natural gas companies began separating CO2 from their product streams.
There are three traditional ways of capturing carbon: post-combustion, pre-combustion and oxy-fuel combustion, which is used in power plants to burn fuel with nearly pure oxygen instead of air. But each of these is typically tied to collecting the emissions from a large point source such as the flue of a power generation facility or manufacturing plant, which requires industrial-scale capture facilities to be economical.
By contrast, Climeworks’ DAC system is modular, consisting of multiple collectors that remove CO2 from the air rather than from point sources. And instead of capturing CO2 in a gas/ liquid laminar flow like other approaches, Climeworks incorporates adsorbent air contact filters that the CO2 sticks to. Climeworks also reduces or even eliminates the transportation costs associated with carbon capture: They can locate a DAC plant right on the storage site.
These innovations have reduced the size and price of Climeworks’ plants.
Climeworks direct air capture plant Photo by Julia Dunlop
Analyzing 500 Variations
Climeworks’ CO2 collectors selectively capture carbon dioxide in a two-step process. First, the air is drawn into the collector with a fan. CO2 is captured on the surface of a highly selective filter material that sits inside the collectors. Then, after the filter material is full of CO2, the collector is closed. Climeworks increase the temperature to between 80 C and 100 C (176 F to 212 F), which releases the CO2. Finally, the high-purity, high-concentration CO2 can be collected.
The gas is then either permanently and safely stored underground, where it can remain for millions of years, or repurposed for industrial applications. For example, the captured CO2 can be turned into carbon black (a component in electronics, printing, and construction), used for carbonating beverages, or processed into synthetic, renewable fuels.
Because CO2 is so vast and dilute, capturing 1 ton requires moving 2,000 to 3,000 tons of air into small channels in the system. Climeworks engineers used Ansys Fluent to analyze airflow volume and speed, understand pressure loss and how it affects the system’s energy consumption, reduce pressure drop, and optimize sorbent volume, that is, how much CO2 will stick to the solid material air contractor filter.
Each plant works in batch mode, with the heating and cooling process beginning only after the filter is saturated. Because releasing the gas and regenerating the collector creates a vacuum in the collection chamber — and the cycle is repeated thousands of times — engineers used Ansys Mechanical to simulate structural stress and fatigue.
Altogether, engineers modeled 500 geometry variations of the air collector while perfecting their design, and did it in far less time than it would have taken to test and build one physical prototype. In fact, engineers estimate that simulation was five to 10 times faster than physical testing would have been. And time savings is cost savings — for Climeworks, its customers, and, ultimately, for a planet trying to avoid the high price of climate change.
Leading scientific studies indicate that by mid-century, 10 billion tons of carbon dioxide will need to be removed from the air every year. Using Ansys software, Climeworks has developed a direct air capture solution that can contribute to that lofty goal.
Climeworks founders Christoph Gebald (l) and Jan Wurzbacher in front of the Climeworks plant Copyright Climeworks. Photo by Julia Dunlop
References:
0 Comments