Green Design

New Materials May Cut Energy Costs for Carbon Capture

A study of over four million absorbent minerals has determined that industrial minerals called zeolites could help electricity producers slash as much as 30 percent of the parasitic energy costs associated with removing carbon dioxide from power plant emissions. The research was done by scientists at Rice University, UC Berkeley, Lawrence Berkeley National Laboratory, and the Electric Power Research Institute.

Commercial power plants do not capture CO2 on a large scale, but the technology has been tested at pilot plants. At test plants, flue gases are funneled through a bath of ammonia-like chemicals called amines. The amines are then boiled to release the captured CO2, and additional energy is required to compress the CO2 so it can be pumped underground. The parasitic energy costs associated with current technology is high - up to one-third of the steam that could be used to generate electricity is siphoned off to boil the amines and liquefy the CO2.

Michael Deem, a professor of physics and astronomy at Rice University, 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 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 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. The chemical industry uses zeolites to refine gasoline and to make laundry detergent and many other products.

(Rice University)