Chemical Processing - November 2007 - (Page 14)

>> IN PROCESS If your highest degree is a bachelor’s, do you regret not going to graduate school? If so, what degree would you have sought? 50 40 Responses (%) 30 20 10 0 Other Masters in Masters in Doctorate in Doctorate in Masters in engineering another engineering another business nontechnical technical or technical or adminis- advanced scientiﬁc scientiﬁc degree tration discipline discipline from methane using a TR membrane (see www.publish.csiro. au/video_clips/polymer_membranes_2.wmv). The researchers are particularly eyeing the removal of carbon dioxide from natural gas. “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 because of the membranes’ more efficient separation capabilities, and would lose less natural gas in their waste products,” says Freeman. “They are excellent for air separation,” he adds. Use in fuel cells is another possibility. Freeman also foresees a potential role as a lessenergy-intensive way to separate olefins and paraffins. The first industrial trial, however, is likely to be for removal of carbon dioxide from power-plant flue gas. Park expects Shells egg on hydrogen output Egg shells may help improve hydrogen production via the water-gas-shift reaction, believe researchers at Ohio State University, Columbus. The shells can serve as a low-cost source of calcium carbonate in the calcium looping process patented by the university, notes L. S. Fan, a professor of chemical and biomolecular engineering. A pilot plant with $2.5 million in funding from the U.S. Department of Energy should start up by the end of the year, Fan expects. In the looping scheme, calcium carbonate is converted to calcium oxide by calcining. The CaO then is used in the reactor to remove CO2 by reforming CaCO3, thus shifting the reaction equilibrium to more H2 production. The reaction takes place at more than 500°C and about 20 atmospheres, but doesn’t require a catalyst and needs far less water than conventional routes, only about the stoichiometric amount, says Fan. Carbon dioxide is reduced to ppb levels, he notes, adding that other contaminants also are removed: H2S to less than 1 ppm, and COS and HCl to ppm-levels. The carbonate then is removed and recalcined to CaO, which is reused; the CO2 recovered is sequestered ultimately. While the calcium looping process can use limestone and other sources of calcium carbonate, egg shells are attractive because they now are discarded and so should be available at low or no cost, notes Fan. In addition, the reactivity of the CaO made from egg shells equals that of the best material now available, so-called engineered limestone developed at Ohio State, he says. After removing the attached membrane, the shells, which are about 95% CaO, are ground to 200-300 micron size particles for calcining. A different application for the calcium-looping process, for CO2 removal during coal combustion, is further along; a pilot plant has been operating for about a year. CP www.chemicalprocessing.com Just over 60% of respondents regretted not going on for a higher degree. To participate in this month’s poll, go to ChemicalProcessing.com. 14 • November 2007 http://www.publish.csiro.au/video_clips/polymer_membranes_2.wmv http://www.publish.csiro.au/video_clips/polymer_membranes_2.wmv http://www.chemicalprocessing.com http://www.westernstates.com http://www.westernstates.com http://www.chemicalprocessing.com

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Chemical Processing - November 2007 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor PAT isn't Standing Pat Pursue the Perfect Plant Eliminate Exchanger Tubing Troubles Portable Conveyor Speeds Paint Production Process Puzzler Plant InSites Equipment & Services Product Spotlight/Classifieds Ad Index End Point

Chemical Processing - November 2007

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