Slurry method developed for CCS
9 Oct 2014
A cost-effective and energy-efficient approach to carbon capture has been developed by researchers in the US, new research suggests.
Carbon capture and storage (CCS) is a process by which as much as 90% of the waste carbon dioxide (CO2) produced by a power plant or manufacturing facility is collected and stored away.
Last week, Laboratorytalk’s sister publication Process Engineering reported on the world’s first CCS plant commencing operations in Canada.
To capture carbon, engineers use two main methods: the first method uses powder-like solid materials which effectively ’stick’ to CO2, while the second method uses liquids that absorb CO2.
“In the materials that are currently used for adsorption the pores are too large and the surrounding liquid would fill them
EPFL director Berend Smit
Now, however, scientists from Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland; University of California, Berkley and Beijing have combined carbon-capturing solids and liquids to develop a modern slurry-based method.
The researchers claim that as a liquid, the new method will be relatively simple to implement on a large scale, while still maintaining the lower costs and energy efficiency of a solid carbon-capturing material.
Berend Smit, director of the Energy Centre at EPFL, explained why his research team chose to develop a slurry-based method for CCS.
“In the materials that are currently used for adsorption the pores are too large and the surrounding liquid would fill them, and not let them capture CO2 molecules. So here we looked at a material - ZIF-8 - whose pores are too small for the glycol’s molecules to fit, but big enough for capturing the CO2 molecules from flue gas.”
Although researchers tested a variety of liquids during the initial design phase, the team found that glycol molecules, which did not negatively affect the slurry’s carbon-capture efficiency, served as the ideal liquid.
According to Smit, ZIF-8 is a good material for carbon-capturing slurries, because it “displays excellent solution, chemical and thermal stability, which is important for repeated regeneration cycles”.
Recognition for the slurry-based method is attributed to a former PhD student in Smit’s laboratory. According to Smit, successfully developing this method could be the key to large-scale implementation of carbon capture.
Smit said that because the slurry technique combines the low cost and efficiency of nano-porous materials with the ease of a liquid-based separation process, the slurry successfully addresses these two main obstacles to the implementation of carbon capture in the real world.
A full account of the research has been published in the journal Nature Communications.
