The new direct air carbon capture system can also capture water
In the energy-water nexus, US startup Avnos has just raised $36 million in Series A funding to bring its new carbon capture and water recycling system to market from the pilot stage. Some of the usual suspects in the oil and gas industry were lining up to support the venture, but it made things interesting when we learned that the U.S. Office of Naval Research had initially helped Avnos shape its technology into shape to attract investors' attention.
Direct air carbon capture, now water capture
Before we get into the Navy, let's start with the latest news. Earlier this week, Avnos shared an embargo press release with CleanTechnica detailing a $36 million funding round for its proprietary carbon capture system called HDAC, an abbreviation for hybrid direct air capture.
The Series A funding round was led by a subsidiary of U.S. energy company NextEra Energy Resources, LLC, which is described by Avnos as "the world's largest wind and solar renewable energy generator and a global leader in battery storage."
So far, everything is fine, although Avnos notes that Shell Ventures is among them. For the record, the other Series A investors are Safran Corporate Ventures, Envisioning Partners, and Rusheen Capital Management.
Avnos also noted that Shell Ventures and ConocoPhillips drove early funding and strategic agreements, as well as JetBlue Ventures and a cleantech accelerator nonprofit called the Grantham Foundation.
SoCalGas went into action
Other early aid came from the U.S. Department of Energy. Launched in 2020, Avnos deploys technology originally developed by the Department of Energy's Pacific Northwest National Laboratory. By 2021, the company had come to the attention of Southern California Natural Gas Company (SoCalGas), which agreed to test the system under the terms of a $3.1 million demonstration project.
The company invested $650,000, the Department of Energy also reached out, and PNNL contributed to the design and development of the system components.
To be clear, SoCalGas doesn't rely on carbon capture systems to do all the heavy lifting to achieve its carbon neutrality goals. The company assesses that carbon capture can play alongside electrification, hydrogen and renewable natural gas, depending on how these pieces come together in terms of rapid scale-up and economic viability.
"Testing a new carbon capture technology, called isothermal water vapor and carbon dioxide capture (IWVC), will provide key insights into its efficiency and operating costs, ultimately determining the cost-effectiveness of its large-scale deployment," SoCalGas explained in a press statement.
The demonstration project aims to capture 1,000 liters (264 gallons) of water and 80 kilograms (176 pounds) of carbon dioxide per day. This is just the beginning.
"We believe this technology has the potential to produce approximately 15 million gallons of water per day while removing 1.8 million tonnes of carbon dioxide per year from the air through a single system," Avnos CEO Will Kain said in a press statement.
Next-generation carbon capture using moisture oscillating adsorbents
Some direct air carbon capture systems employ adsorbent materials to capture water vapor and carbon, similar to a small packet of desiccant in new shoes and other product boxes. The adsorbent material attracts moisture to its surface. In contrast, absorbent materials swell when ingested into liquids, and sponges are a prime example.
In terms of the relationship between energy and water, there are two challenges to using adsorbents for direct air carbon capture systems. One relies on water resources to capture carbon, and the other relies on heat energy to extract carbon. Apparently, PNNL researchers have found a solution to this problem.
"High temperatures are often used to regenerate desiccant, which is too energy-intensive and costly for DACs," explains Dr. Peter McGrail, a laboratory researcher at the lab. "IWVC's desiccant is regenerated without any external heating, which makes it very economical to produce water and carbon dioxide. ”
The two-stage process begins with the binding of water vapor and carbon dioxide to the adsorbent. In the second step, the water is condensed out and the carbon dioxide is compressed elsewhere. SoCalGas lists storage as one of its destinations, but they also point out that CO2 can be used to make fuels and other products, which is a good guess given the growth of the green hydrogen and e-fuel industries since 2021.
What about the US Navy?
CleanTechnica is in contact with Avnos to get some details about the Navy's early contributions to its technology.
Now, let's note that energy-efficient water recycling is a key issue for the Navy, so it's no surprise that the Naval Research Laboratory is showing interest in new cutting-edge technologies.
In 2017, the U.S. Naval Research Laboratory, together with the National Science Foundation of China, funded a study on carbon capture of rapidly oscillating moisture carbon dioxide adsorbents. The study was authored by researchers Xiaoyang Shi from Columbia University, Qibin Li from Chongqing University in China, Tao Wang from Zeizhiang University in China, and Klaus S. Lackner from Arizona State University.
This particular study involved absorbents, not adsorbents. Detailed information is available in PLOS ONE magazine under the title "Kinetic Analysis of Anion-Exchange Absorbers for Capturing CO2 from Ambient Air".
Perhaps due to the rapid development of materials science, the preferred term in recent years seems to be the common old adsorbent. In 2020, Klaus Lackner described how it works in a proposed "mechanical tree" that deploys a water oscillation mechanism to capture carbon at 1,000 times faster than natural trees.
In an article published in 2020, Lackner explained, "The concept is not surprising to me because I've been playing around for a decade, but the concept of moisture wobble is still very new and very different from other ways of loading and unloading adsorbents.
"We discovered this phenomenon 14 years ago, and for a long time how it worked was a mystery. Now it seems obvious," he added.
In 2021, a Chinese team reviewed the carbon capture literature and identified water oscillation technology as the most promising path to low-cost carbon recovery and water recovery.
"Recently, a new moisture oscillation technique was proposed and a new carbon monoxide method 2 capture was investigated (Wang et al., 2011). The adsorbent is an anion exchange resin that carries carbonate ions as CO2 adsorbed by water oscillation, based on the mechanism of water-driven reversible hydrolysis reactions of carbonate ions in confined nanoenvironments such as nanopores (Shi et al., 2016)," the team explained. Compiled by Chen Jiaoyun
"Driven by the evaporation of water, the resin has a high affinity for CO2 when the surrounding environment is dry and when it is wet. This unique mechanism results in a moisture oscillating adsorbent for CO2 adsorption, showing a low CO2 adsorption heat of ∼32 kJ/mol (Shi et al., 2020a), as the traditional thermal oscillation process is replaced by water evaporation," they added.
Going back to the Navy's funding, mentioning that carbon capture is mixed with electric fuel production, which makes sense given the Navy's interest in producing fuel on the go in addition to water recycling.