Carbyon ($3M for fast swing carbon capture)

Carbyon, a Netherlands-based company founded in 2019, develops direct air capture (DAC) technology that removes carbon dioxide (CO₂) directly from the air. Carbyon’s technology uses a fast swing process by means of a continuously rotating drum that consists of activated carbon fibers functionalized with amines. The fast swing process is the key to lower the energy consumption as well as the cost of the machine. The company’s goal is to turn direct air capture into an affordable and scalable technology that can be used to stop climate change. Carbyon has won XPRIZE Milestone Award for Carbon Removal in 2022.

Challenges: carbon emissions and Direct Air Capture

Carbon emissions

Since the early 1900s, carbon dioxide (CO₂) levels in the atmosphere have increased by 50% due to human activities. When fossil fuels (such as coal, oil, and natural gas) are burned for energy production, transportation, and industrial processes, CO₂ is released into the atmosphere. This excess CO₂ acts as a greenhouse gas, trapping heat and causing the air and ocean temperatures to rise. CO₂ emissions play a crucial role in driving climate change.

This warming effect has caused the global average temperature to rise by about 1.1 ºC since the pre-industrial period. This has led to rising in the frequency and intensity of extreme weather events, melting of polar ice caps and glaciers and rising sea levels, shifts in species ranges and increased risk of species extinction, agriculture and food security, and ocean acidification.

To mitigate these impacts, the Paris Agreement aims to limit global warming to well below 2 ºC above pre-industrial levels. The Intergovernmental Panel on Climate Change (IPCC) estimates that a “carbon budget” of about 500 GtCO₂, which corresponds to about ten years at current emission rates, provides a 66% chance of limiting global warming to 1.5 ºC.

Direct Air Capture

Direct Air Capture (DAC) is a process that extracts CO₂ directly from the atmosphere, as opposed to industrial emissions with a high CO₂ content. The captured CO₂ can then be either permanently stored in deep geological formations, thereby achieving CO₂ removal (CDR), or used as a climate-neutral feedstock for a range of products that require a source of carbon.

The basic principle of DAC involves using large-scale machines or facilities equipped with specialized filters or sorbents which are designed to attract and bind with CO₂ molecules from the air while allowing other gasses, such as nitrogen and oxygen, to pass through. After the CO₂ is captured, it is separated from the sorbent through a regeneration process, resulting in the release of CO₂.

DAC technology employs a variety of methods, but chemical sorbents or solvents are typically used to capture CO₂. These sorbents can chemically react with CO₂ to form solid compounds or dissolve the CO₂ in a solvent. The captured CO₂ is then released from the sorbent or solvent via heating or other processes, allowing for its storage or utilization.

Direct air capture technology challenges

DAC plays an important and growing role in net-zero pathways. Capturing CO₂ directly from the air and permanently storing it removes the CO₂ from the atmosphere, providing a way to balance emissions that are difficult to avoid, including from long-distance transport and heavy industry. DAC has seen a surge in interest and investment over the past few years, and a growing number of companies are entering the market due to the realization that carbon removal will increasingly be needed to meet national and global climate goals, as well as the advantages of DAC relative to other carbon removal technologies.

However, this technology is still in its infancy and faces several challenges that are stunting its global adoption and deployment.

One of the main challenges is that CO₂ is present in the air at a much lower concentration than other commonly targeted sources, such as flue gasses resulting from energy generation and industrial processes. This makes it technically challenging and requires a lot of energy.

As carbon dioxide removal from ambient air is an energy-intensive process, DAC technology is more expensive per ton of CO₂ removed than many mitigation strategies and natural climate solutions. Today, the price range for DAC ranges between $250 and $600. By the end of this decade, however, the cost of DAC technology is projected to fall to $250-$300/mtCO₂e (million tons of CO₂ equivalent) for a multi-megaton capacity range. If further industrialization is accomplished within the ecosystem of this emerging industry, prices may fall to between $100 and $200/t.

The sociopolitical acceptance of DAC is also a challenge. Currently, there is no established market for carbon removal, and the demand for carbon removal is not yet sufficient to support the large-scale deployment of DAC. Some advocates worry the carbon capture process may not be scaled up fast enough to make an impact. However, the demand for carbon removal is expected to increase as more countries and companies set net-zero targets and seek to offset their emissions. In addition, governments and other stakeholders must provide substantial funding and support.

Direct air capture companies

Several companies, such as Carbon Engineering, Climeworks, Heirloom, Noya, and Mission Zero, are developing DAC technologies.

Carbon Engineering DAC technology is an engineered mechanical system that extracts CO₂ from the air using a combination of fans, filters, and chemical reactions. The captured CO₂ is then compressed and stored underground or reused. Carbon Engineering’s DAC technology is capable of capturing millions of tons of CO₂ annually, and individual DAC facilities can be built to capture one million tons of CO₂ annually.

Climeworks specializes in DAC technology that extracts CO₂ from the air using a solid sorbent. The captured CO₂ is then released through a regeneration process, while the sorbent material is reused. Climeworks has developed several DAC plants worldwide and is working to scale up its technology to capture millions of tons of CO₂ annually. The company operates the largest operating DAC plant, Orca, in the world. The plant is located in Iceland and is capable of drawing down the volume of carbon dioxide emissions equivalent to approximately 870 cars annually.

Heirloom uses limestone (CaCO₃) instead of synthetic sorbents to capture CO₂ from the air and store it safely and permanently. Limestone is heated in renewable-energy powered calciners to remove CO₂ and produce Ca(OH)₂ sorbents from the hydration of CaO powders. Ca(OH)₂ sorbents are placed on vertically stacked trays, and algorithms are used to optimize their capacity to absorb CO₂ in different environmental conditions. Heirloom’s DAC technology accelerates the natural property of limestone, reducing the time it takes to absorb CO₂ from years to just three days. The company claims that its technology has the lowest peer-reviewed, at-scale cost of any direct air capture technology on the market.

Noya has developed a unique DAC technology that combines the existing pieces of industrial cooling towers with solid CO₂ sorbents. This transforms industrial cooling towers into CO₂ capture machines, which radically reduces the upfront capital costs and installation time required to perform direct air capture. Therefore, Noya’s approach to DAC will enable them to scale quickly and provide low-priced carbon removal in the near-term.

Mission Zero has developed a DAC technology that continuously captures CO₂ from the air with low energy consumption. Mission Zero uses a well-established electrodialysis technology to capture CO₂ from the air and turns CO₂ into carbonic acid (H₂CO₃), which dissociates into HCO₃⁻ and proton (H⁺). The H₂CO₃ solution is circulated through an electrodialysis cell, which separates HCO₃⁻ from the absorbent solution by passing it through an anion-exchange membrane into a second absorbent solution, where HCO₃⁻ anions recombine with protons in the second absorbent solution to form carbonic acid, which readily decomposes into CO₂ in the release vessel where CO₂ is collected and stored.

Carbyon Technology

Carbyon develops a low-cost, energy-efficient DAC technology that uses a fast swing process by means of a continuously rotating drum. The rotating drum comprises activated carbon fiber membranes. The surface of fibers are functionalized with a monolayer of amines that are used as CO₂ adsorbents. Such a thin surface sorbent allows a rapid CO₂ absorption at ambient temperature and fast regeneration below 100 ºC. Thereby, one cycle of absorption and regeneration occurs in less than 5 seconds. The fast swing CO₂ capture process is the key to lower the energy consumption as well as the cost of the machine.

Carbyon direct air capture technology

The diagram below depicts the system of the DAC technology developed by Carbyon.

The system comprises a drum containing porous CO₂ sorbent materials, at least one sorption chamber, at least one regeneration chamber, and a mechanism for rotating the drum from the sorption chamber to the regeneration chamber and back. The sorption chamber has inlets and outlets for the airflow that passes over the porous carbon fiber support structure. For regeneration of sorbents, the regeneration chamber is heated to a moderately high temperature by heating elements. The regeneration chamber also has outlets for discharging CO₂.

The diagram below depicts Carbyon’s carbon fiber membrane with microporous structures, which offers a large surface area for coating a monolayer of amine sorbents. The amine sorbents coat the surface of carbon fiber via a wet impregnation method.

Carbyon carbon fiber support coated with a monolayer of sorbent molecules (Source Carbyon).

The process for CO₂ absorption by the monolayer of sorbents is depicted in the diagram below.

Carbyon process of CO₂ captured by a thin layer of sorbent molecules coated on the wall of the micropore (ref. WO2022013456A1).

During operation, air enters the micropores and largely stands still, whereas air outside the opening of the pores flows. The amine absorbs CO₂ from the air in the micropores, resulting in a decrease in CO₂ concentration and CO₂ partial pressure. Therefore, mainly CO₂ molecules diffuse into the pores and are absorbed by the amines until the sorbent is saturated. Other molecules in the airflow that are not adsorbed by the sorbent hardly diffuse into the pores because their partial pressure is not reduced in the pores.

Therefore, CO₂ molecules are selectively sucked out of the airflow and captured by the sorbent. Moreover, the process avoids the need for large pressure differences of the airflow passing through the sorption chamber, as is required by conventional DAC technologies, thereby minimizing the energy input.

When only surface adsorption takes place, the surface adsorption is much quicker than bulk absorption, as it avoids solid or liquid state diffusion. In addition, the capacity of a certain volume of sorbent is significantly reduced. Therefore, the sorbent is saturated with CO₂ faster, resulting in a higher adsorption rate. To liberate the CO₂ molecules from the monolayer sorbents during sorbent regeneration, only a short heat pulse is required. The regeneration temperature is below 100 ºC, which reduces the energy input significantly.

Thus, the surface sorbent enables shorter cycle times for the sorbent to switch between a sorption stage and a regeneration stage and minimizes the energy requirement.

How does Carbyon direct air capture technology work?

Air flows through the sorption chamber over a microporous structure coated with a monolayer of amine sorbents. CO₂ is selectively captured at ambient temperature, as described previously. Due to the thinness of the sorption layer in the microporous structure, the residence duration of the sorbent within the sorption chamber is less than 5 seconds.

The CO₂-saturated amine sorbents are rotated from the sorption chamber to the regeneration chamber, where they are regenerated at temperatures between 65 and 100 ºC by liberating CO₂ from the sorbent. The process typically occurs at the same time scales of less than 5 seconds. The released CO₂ is extracted from the regeneration chamber and either stored for utilization or buried underground.

The regenerated sorbent is then rotated towards the sorption chamber and used again for capturing CO₂ from air. Absorption and regeneration processes are continuous.

Carbyon Patent

WO2022013456A1 Device and process for the direct carbon dioxide capture from air

Carbyon Products

Carbon offset credit market

The market value of carbon offset credits varies widely. In current carbon markets, the price of one carbon credit can range from a few cents per metric ton of CO₂ emissions to $15/mtCO₂e (metric tons of CO₂ equivalent) or even $20/mtCO₂e. However, the voluntary carbon offset market, which was worth about $2 billion in 2021, is projected to grow to $10-40 billion by 2030, transacting 0.5-1.5 billion tons of CO₂ equivalent, as opposed to the current 500 million tons. The total value of carbon credits produced and sold to help companies and individuals meet their de-carbonization goals could approach $1 trillion as soon as 2037.

Carbyon product

The company aims to reach gigaton scale in the 2030s and substantially contribute to mitigating climate change. The company’s target is a cost of 50 euros/ton for CO₂ capture, and its approach is radically distinct from competing technologies. The company has developed lab-scale prototypes and is developing outdoor piloting systems. By 2024, the company will provide commercial CO₂ capture machines.