Phlair (formerly known Carbon Atlantis), a German cleantech startup founded in 2022, develops an innovative carbon removal technology. Their approach uses electrolysis to create acid and alkaline solutions that directly capture CO₂ from the atmosphere. This technology aims to offer a scalable and cost-effective method for reducing atmospheric CO₂ levels, contributing to climate change mitigation efforts.
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Challenges: carbon emissions
Since the early 1900s, atmospheric carbon dioxide (CO₂) levels have surged by 50% due to human activities, primarily the combustion of fossil fuels for energy production, transportation, and industrial processes. This excess CO₂ acts as a greenhouse gas, trapping heat and causing air and ocean temperatures to rise. The resulting warming effect has elevated the global average temperature by approximately 1.1 ºC since the pre-industrial period.
This increase of the global average temperature has led to a cascade of environmental impacts, including more frequent and intense extreme weather events, melting polar ice caps and glaciers, rising sea levels, shifts in species ranges, increased risk of species extinction, challenges to agriculture and food security, and ocean acidification.
To address these pressing issues, the Paris Agreement aims to limit global warming to well below 2 ºC above pre-industrial levels.
The Intergovernmental Panel on Climate Change (IPCC) has calculated a critical "carbon budget" to address global warming. This budget, estimated at roughly 500 gigatons (GT) of CO₂, represents the maximum amount of CO₂ that can be emitted while maintaining a 66% probability of limiting global temperature rise to 1.5 ºC above pre-industrial levels.
At current emission rates, this budget would be exhausted in approximately a decade, highlighting the pressing need for swift and significant reductions in CO₂ emissions. This stark timeline emphasizes the urgency of implementing immediate and comprehensive measures to curb greenhouse gas emissions across all sectors of the global economy.
Phlair Technology
Direct Air Capture (DAC) technologies use large-scale facilities with specialized filters or sorbents to extract CO₂ from the air. The captured CO₂ is then separated for geological storage or use as a climate-neutral feedstock.
DAC is energy-intensive and costly due to low atmospheric CO₂ concentration, with current costs ranging from $250 to $600 per ton of CO₂ equivalent. Electrochemical DAC methods, which split water (H₂O) into proton (H⁺) and hydroxide ion (OH⁻) to create CO₂-capturing solutions, potentially offer lower energy requirements and costs compared to heat-based approaches, as illustrated in the diagram below.
The equilibrium dissociation of CO₂ in water involves the formation of H⁺ and OH⁻ ions, and the reaction between CO₂ and these ions to form HCO₃⁻.
H₂O ⇆ H⁺ + OH⁻
CO₂ + H⁺ + OH⁻ ⇆ HCO₃⁻ + H⁺
In alkaline solutions, this equilibrium shifts towards HCO₃⁻ formation, while acidic solutions promote CO₂ formation. This principle allows alkaline solutions to absorb dilute CO₂ from air, creating concentrated HCO₃⁻ solutions. Adding an acidic solution to this concentrated HCO₃⁻ solution then releases pure CO₂, effectively capturing it from the atmosphere.
Common electrochemical processes for splitting water into an acidic and basic stream include electrocatalytic cation exchange module (E-CEM) systems and bipolar membrane electrodialysis systems (BPMED). Several startups have used these systems to capture CO₂ from seawater. E-CEM systems have an energy consumption around 20,000 kWh/t CO₂, while BPMED systems have better energetic efficiency, with 920-1400 kWh/t CO₂.
Phlair has developed a DAC system using electrochemical hydrogen circulation for atmospheric CO₂ removal. Their core technology is an electrolyzer that produces H₂ and an alkaline solution at the cathode. The H₂ is then circulated to the anode, where it's oxidized to form an acidic solution. These alkaline and acidic solutions are utilized in CO₂ removal devices to capture atmospheric CO₂.
How Phlair captures CO₂ from the air
As illustrated in the diagram below, Phlair's DAC system employs a continuous electrolysis process to capture CO₂ from the atmosphere.