Greenlyte Carbon Technologies, a startup founded in 2022 and located in Essen (Germany), has developed a technology that efficiently captures carbon dioxide (CO₂) directly from the atmosphere by their innovative CO₂ absorbent and then uses the CO₂-loaded absorbent to produce hydrogen (H₂) and CO₂ by an electrolysis cell. The produced H₂ and CO₂ from the electrolysis cell can be used as raw materials to produce green hydrocarbon fuels that are alternative to fossil fuels.
Challenges: CO2 capture
Carbon emissions are a major contributor to climate change, as the release of CO₂ and other greenhouse gasses into the atmosphere trap heat and cause the planet’s temperature to rise. Carbon emissions come from various sources, including burning fossil fuels for energy, deforestation, and industrial processes.
To reduce carbon emissions, many countries and companies are exploring ways to capture and store carbon dioxide. Carbon capture and storage (CCS) involves capturing CO₂ emissions from power plants and industrial processes and then storing them underground or using them for other purposes.
One of the main challenges of CCS is the cost. Capturing CO₂ is an energy-intensive process that requires expensive equipment, and transporting and storing CO₂ also adds to the cost. As a result, many CCS projects have struggled to attract funding and have been slow to develop.
Another challenge is the scale of CCS required to make a significant impact on carbon emissions. Even if CCS were widely implemented, it would only capture a portion of global emissions, and other measures would still be needed to reduce emissions from transportation, agriculture, and other sources.
There are also concerns about the safety and effectiveness of CCS. Storing large amounts of CO₂ underground could potentially cause earthquakes or leaks, which could be dangerous and expensive to remediate. Additionally, some critics argue that CCS is a “band-aid” solution that does not address the root causes of carbon emissions.
Despite these challenges, many experts believe that CCS could play an important role in reducing carbon emissions, particularly in industries that are difficult to decarbonize, such as steel and cement production. Research is ongoing to improve the efficiency and reduce the cost of CCS, and governments and companies are investing in CCS projects as part of their climate strategies.
Greenlyte Carbon Technologies (Greenlyte) has developed a system that captures CO₂ directly from the atmosphere using their innovative CO₂ absorbent and then uses the CO₂-loaded absorbent to produce hydrogen (H₂) and CO₂ using an electrolysis cell. The produced H₂ and CO₂ by the electrolysis cell can be used as raw materials for the production of green hydrocarbon fuels that are alternative to fossil fuels.
Greenlyte CO₂ capture system
Below is a diagram of the Greenlyte carbon capture system, which consists of a CO₂ absorbent unit and a three-chamber electrolysis cell.
The carbonate-based CO₂ absorbent in the CO₂ capture unit is composed of PEG, water (H₂O), and K₂CO₃. The absorbent absorbs CO₂ from ambient air or industrial air efficiently. This process involves the conversion of the potassium carbonate (K₂CO₃) to potassium bicarbonate (KHCO₃) via the following reaction:
K₂CO₃ + CO₂ + H₂O → 2KHCO₃
The KHCO₃ solution feeds the electrolysis cell’s middle chamber. The middle chamber is separated from the anode chamber by a bipolar membrane and from the cathode chamber by a membrane permeable to potassium ions (K⁺).
By applying a voltage, oxygen (O₂) is produced in the anode chamber via the following chemical reaction:
2OH⁻ → H₂O + O₂↑ + 2e⁻
The bipolar membrane is a special type of ion-exchange membrane that consists of a cation- and an anion-exchange layer, allowing the generation of protons and hydroxide ions via a water dissociation mechanism:
H₂O → H⁺ + OH⁻
In the middle chamber, a chemical reaction produces CO₂:
KHCO₃ + H⁺ → CO₂↑ + H₂O + K⁺
The potassium ions diffuse to the cathode chamber through the potassium permeable membrane.
In the cathode chamber, H₂ and K₂CO₃ are produced via the following chemical reactions:
2H₂O + 2e⁻ → H₂↑ + 2OH⁻
KHCO₃ + K⁺ + OH⁻ → K₂CO₃ + H₂O
The individual gas streams can be collected separately. CO₂ and H₂ are used as raw materials for the production of green hydrocarbon fuels.
The CO₂-depleted solution in the middle chamber can be recycled to the cathode chamber.
The K₂CO₃ in the cathode chamber can used again as the component of the carbon adsorbent for an air flow.
Greenlyte CO₂ absorbent
The Greenlyte carbon dioxide absorbent consists of water (20 -30 wt%), PEG 200 or PEG 300 (60 -70 wt%), and K₂CO₃ (10-20%). The absorbent is chemically stable, non-toxic, and inexpensive, allowing for large amounts of absorbent to be provided. Such a composition can preferably be used flexibly under moderate ambient conditions and with a long service life. The carbon dioxide absorbent can be operated at atmospheric humidities of 70% rh to 80% rh. The ambient or bath temperature can be between 20 and 30 ºC.
The composition of absorbent is effective in absorbing carbon dioxide from ambient air or industrial exhaust gas. The absorbent can process air streams has fast uptake kinetics, removing carbon dioxide down to very low levels.
PEG 200 or PEG 300 is added to adjust the absorbent’s water vapor partial pressure. PEG is an important component in the carbon dioxide adsorbent, as its interaction with the carbon dioxide contributes to the physical binding of the carbon dioxide in the absorbent. As a result, these substances can engage in a strong physical interaction with the CO₂, which is the basis for their high absorption capacity and rapid kinetics at low CO₂ partial pressures.
The Greenlyte carbon dioxide adsorbent solves the disadvantages of conventional carbon dioxide absorbents, which are affected by changes in water concentration and humidity.
- WO2022184840A1 Process and absorbent for absorbing carbon dioxide from the air
- DE102021105154A1 Process and absorbent for absorbing carbon dioxide from the air
Greenlyte Carbon Technologies aims to develop and implement a direct air capture (DAC) technology that captures CO₂ while generating hydrogen as a byproduct. The company’s goal is to free the world from fossil fuels by producing green hydrocarbons from ambient air. During its Phase 1 in 2023, Greenlyte aims to construct a pilot plant that can capture 100t CO₂ per year.
Greenlyte Carbon Technologies has raised a total of $3.5M in funding over a Pre-Seed round, which was raised on Mar 10, 2023.
Greenlyte Carbon Technologies is funded by 3 investors, including Green Generation Fund, Carbon Removal Partners, and Earlybird Venture Capital. Green Generation Fund and Carbon Removal Partners are the most recent investors.
Florian Hildebrand is CEO.
Greenlyte Board Member and Advisor
Udo Jung is Board Member.