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Sci Tech
Faster, better stripping of CO2 from natural gas
Like a sponge that only soaks up certain chemicals, a new modified plastic permits carbon dioxide or other small molecules to go through hour-glass shaped pores within it, while impeding natural gas (methane) movement through these same pores.
The thermally rearranged (TR) plastic works four times better than conventional membranes at separating out carbon dioxide through pores.
Several projects
When developed for commercial use, the plastic could also be used to isolate natural gas from decomposing garbage, the focus of several experimental projects.
The TR plastic described in a recent issue of Science could also help recapture carbon dioxide being pumped into oil reservoirs in West Texas and elsewhere, where it serves as a tool for removing residual oil. The material greatly improves the ability to separate global warming-linked carbon dioxide from natural gas as the gas is prepared for use, according to engineers at The University of Texas at Austin who have analyzed the new plastic’s performance.
Dr. Ho Bum Park, a postdoctoral student in the laboratory of Professor Benny Freeman, also found that TR plastic membranes act quicker.
They permit carbon dioxide to move through them a few hundred times faster than conventional membranes do — even as they prohibit natural gas and most other substances from travelling through their pores for separation purposes, according to a University of Texas, Austin, press release.
Park investigated whether plastics made of rings of carbon and certain other elements could work well at separating carbon dioxide out of gas wastes produced by power plants.
High temperatures
Separating the greenhouse gas from other gases at power plants must occur at high temperatures, which usually destroy plastic membranes.
It was not only found that the TR plastic could handle temperatures above 600 degrees Fahrenheit, but that the heat transformed the material into the better performing membrane described in Science. “If this material was used instead of conventional cellulose acetate membranes, processing plants would require 500 times less space to process natural gas for use,” said Freeman. — Our Bureau
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