Environmental Protection: Carbon Capture Conversion Unit Shows Promise

Engineers at the University of Illinois Chicago (UIC) create a novel device that combines a carbon capture system with an ethylene conversion system.
Feb. 17, 2023
3 min read
Source: Meneesh Singh, et al.
Lab Index 1 Ethylene Pic 63ea9e5cc185a
A new device developed by engineers at the University of Illinois Chicago (UIC) combines a carbon capture system with an ethylene conversion system.
“This is the first demonstration of a net-negative, all-electric integrated system to capture carbon from pollutants and create a highly valuable resource,” says Meenesh Singh, UIC assistant professor in the department of chemical engineering.
Previously, the same group demonstrated the CO2-ethylene conversion unit (see, “Captured Carbon Serves as Ethylene Feedstock”).
For this work, Singh’s group modified a standard artificial leaf system with inexpensive materials to include a water gradient — a dry side and a wet side — across an electrically charged membrane (Figure 1).
Source: Jim Young/UIC Engineering.
Figure 1. Engineers at the University of Illinois Chicago have built a device that captures carbon from flue gas and converts it to ethylene.
Figure 1. Engineers at the University of Illinois Chicago have built a device that captures carbon from flue gas and converts it to ethylene.
On the dry side, an organic solvent attaches to available CO2 to produce a concentration of bicarbonate, or baking soda, on the membrane. As bicarbonate builds, these negatively charged ions are pulled across the membrane toward a positively charged electrode in a water-based solution on the membrane’s wet side. The liquid solution dissolves the bicarbonate back into CO2, so it can be released and harnessed for CO2 conversion. 
Run 24/7, the system remained stable and captured CO2 at a rate of 24 g/day while producing ethylene at a rate of 0.2 g/day.
“From the reaction stoichiometry, we need about 3 g of CO2 to make 1 g of ethylene. So, we can make much more ethylene — up to 8 g/day — with a 24-g/day CO2 capture rate. However, for concept validation we demonstrated production of only about 0.2 g/day,” Singh notes.
The group’s next step is to scale the integrated system to produce ethylene at higher rates — 1 kg/day — and capture carbon at a rate higher than kgs/day.
However, while the electrodialysis unit has an expandable stack that can accommodate up to 5 m2 of membrane, the electrolysis unit needs to be scaled gradually from 1 cm2 to 10 cm2 and then to 100 cm2 and 1 m2.
Next step is to scale the integrated system to produce ethylene at higher rates.
“We are currently working to establish up to 100 cm2 of electrolyzer which can produce up to 100 g/day of ethylene, with an aim to design an electrolyzer that can make 10 kg/day of ethylene,” Singh explains.
He adds that the modular, stackable design will vary with scale, too. For example, a generation-1 modular design can accommodate electrode areas from 10–100 cm2. Generation-2 is being designed to accommodate electrode areas from 100–2,000 cm2, while a production scale module will range from 0.2–3 m2. “Every module design for each scale range is different,” he says.

About the Author

Seán Ottewell
Email

Seán Ottewell

Editor-at-Large

Seán Ottewell is a freelance editor based in Ireland. He has an impressive background in the chemical industry. After earning his degree in biochemistry at Warwick University, UK, he earned his master's in radiation biochemistry from the University of London. His first job out of school was with the UK Ministry of Agriculture, Fisheries and Food, London, where he served as scientific officer with the food science radiation unit.

From there he entered the world of publishing. In 1990, he was the assistant editor of The Chemical Engineer, later moving on to the chief editor's position. Since 1998, he has been a regular contributor to European Process Engineer, European Chemical Engineer, International Oil & Gas Engineer, European Food Scientist, EuroLAB, International Power Engineer, published by Setform Limited, London, UK.

Chemical Processing has been proud to call Ottewell Editor at Large since 2007.

He and his family run a holiday cottage in the small village of Bracklagh in East Mayo. He also fancies himself an alpaca farmer.

Sign up for our eNewsletters
Get the latest news and updates

Related

Workforce Matters: The Club Nobody Admits They're In
Could vs. Should: What 'Jurassic Park' Can Teach Us About Process Safety
How Pilot Operated Relief Valves Work
Sponsored
Discover the Strength of Model 7A00 Valves
Sponsored