In a new study published March 2021 in the International Journal of Greenhouse Gas Control, researchers from the Department of Energy’s Pacific Northwest National Laboratory (PNNL), explain a new carbon capture method using the solvent, known as EEMPA. The solvent’s qualities allow for the new technology to require 17% less energy than other methods used at the moment. As a result, the costs are reduced by 19% compared to other technologies for carbon capture.
The research efforts come as governments and industry counterparts are trying to scale down the cost of carbon capture. The U.S. Department of Energy’s goal for commercially available technology for CO2 capture is a cost of $30 per metric ton by 2035. The time pressure to curb dangerous emissions is pushing scientists to roll their sleeves to meet and exceed those targets.
“EEMPA has some promising qualities,” said chemical engineer Yuan Jiang, lead author of the study. The main qualities pointed out are:
- less viscous than other water-lean solvents
- it can capture CO2 with less water content
- the carbon capture method could be utilized in existing infrastructure
EEMPA Carbon Capture Method Explained
The chemical process for CO2 capture that is industrially widespread right now is using conventional amine-based solvents. However, amines have limitations since they use a lot of water. They also must be boiled at high temperatures to remove CO2 and then cooled before they can be reused which is expensive. EEMPA overcomes those barriers in a way that is also more economical.
The EEMPA’s less viscosity is achieved by using molecules that are aligned in a way that promotes internal hydrogen bonding. That leaves fewer hydrogen atoms to interact with neighboring molecules.
The process is explained with comparison to children running through a ball pit. If two kids hold their hands while passing through, they move slowly. But if they hold their own hands instead, they pass as two smaller objects that move faster. Internal hydrogen bonding also leaves fewer hydrogen atoms to interact with overall, akin to removing balls from the pit.
EEMPA can absorb CO2 from a power plant and later release it as pure CO2 for $47.10 per metric ton. Current commercial technology is capable of capturing carbon at around $58.30 per metric ton, according to a DOE analysis.
The PNNL team figured out another way to reduce costs. If plastic is used instead of steel for equipment in the infrastructure, that could drive the overall cost down by another $5 per metric ton. The estimate is proposed in a study led by Jiang in 2019.
EEMPA will continue to be tested at an increasing scale, so further refinements in the chemistry, improving efficiency and reducing costs, could be seen. This is another effort to reduce the barriers keeping carbon capture technologies from commercial use. Right now it looks like its going to be a success.