New materials to cut costs for CO2 capture
31 May 2012
Study discovers zeolite minerals that are one-third more efficient for carbon capture
A detailed analysis of more than 4 million absorbent minerals has determined that new materials could help electricity producers cut as much as 30 percent of “parasitic energy” in power plants.
The research was undertaken by scientists at Rice University, the University of California, Berkeley, Lawrence Berkeley National Laboratory (LBNL) and the Electric Power Research Institute (EPRI).
Coal- and natural-gas-fired power plants account for about half of the carbon dioxide (CO2) that humans add to the atmosphere each year.
However current technology for capturing that CO2 and storing it underground can use up as much as one-third of the steam the plant could otherwise use to make electricity.
In the new study, researchers found that commonly used industrial minerals called zeolites could significantly improve the energy efficiency of carbon capture technology.
“It looks like we can beat the current state-of-the-art technology by about 30 percent, and not just with one or two zeolites,” said study co-author Michael Deem, a Rice Professor of Bioengineering and professor of physics and astronomy.
Deem said the new study is the first to compare the parasitic energy costs for a whole class of carbon-capture materials.
The study found dozens of zeolites that could remove CO2 from flue gas for a lower energy cost than conventional amines could.
Zeolites are common minerals made mostly of silicon and oxygen. About 40 exist in nature, and there are about 160 man-made types.
All zeolites are highly porous - like microscopic Swiss cheese - and the pore sizes and shapes vary depending upon how the silicon and oxygen atoms are arranged.
The pores act like tiny reaction vessels that capture, sort and spur chemical reactions of various kinds, depending upon the size and shape of the pores.
In 2007, Deem and colleagues used computers to calculate millions of atomic formulations for zeolites, and they have continued to add information to the resulting database, which contains about 4 million zeolite structures.
In the new study, the zeolite database was examined with a new computer model designed to identify candidates for CO2 capture.
Focusing on the energy costs of capture, release and compression, they were able to create a formula to calculate the energy consumption for any materials in the zeolite database.
