3D-printed device boosts carbon capture efficiency
Researchers from the US Department of Energy’s Oak Ridge National Laboratory have designed a 3D-printable device which enhances the capture of carbon dioxide through heat exchange.
While governments are primarily focused on cutting greenhouse gas emissions in order to meet their obligations under the Paris Agreement and mitigate climate change, there is also interest in carbon capture and storage solutions. Carbon capture technologies could be installed at significant sources of carbon – such as power plants and factories – to mitigate their environmental impact, as part of holistic decarbonisation efforts.
The device designed by the Department of Energy researchers is focused on improving the process of carbon absorption, which in a flue-gas stream from smokestacks is placed in contact with a solvent which reacts with the gas. This process typically produces heat when carbon dioxide interacts with the solvent, in turn diminishing the capability of the solvent to react with carbon dioxide, thus reducing efficiency.
Using 3D printing, the researchers were able to custom design a device which removes this excess heat while keeping costs low.
The 3D-printed device integrates a heat exchanger with a mass-exchanging contactor and is installed in the upper half of a 1m-tall column consisting of stainless-steel packing elements. Manufacturing via 3D printing renders it possible to integrate a heat exchanger within this column without disturbing the geometry, maximising contact surface area between the gas and liquid streams.
Embedded coolants were added inside the packing elements’ corrugated sheets, allowing for heat exchange.
“Prior to the design of our 3D-printed device, it was difficult to implement a heat exchanger concept into the [carbon] absorption column because of the complex geometry of the column’s packing element,” said Dr Xin Sun, principal investigator. “With 3D printing, the mass exchanger and heat exchanger can co-exist within a single multifunctional, intensified device.”
The researchers created their prototype from aluminium, which can be 3D printed, and has good thermal conductivity and structural strength. However, the researchers say that the device can be manufactured using other 3D-printable materials such as high thermal conductivity polymers and other metals.
Sun and her colleagues put their device to the test in two capture absorption experiments. In one experiment, the gas flow rate was varied; in the other, the solvent flow rate was varied. In both experiments, there were substantial improvements in carbon capture rate with a peak in capture at 20 per cent carbon dioxide concentration. Increase in capture rate varied from 2.2 per cent to 15.5 per cent depending on conditions.
“The success of this 3D-printed intensified device represents an unprecedented opportunity in further enhancing carbon dioxide absorption efficiency and demonstrates proof of concept”, Sun said.
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