Chemical Processing - March 2008 - (Page 14)

>> IN PROCESS sure are best for loading a gas, notes Chandler. “I’d say the largest challenge is producing the building blocks that make these structures in large scales cheaply and efficiently,” he adds. “The present compound and its synthesis would equate to a cost of approximately $20 to $25/kg. Therefore, at the present time, this material would only be applicable to specialty markets until a cheaper way is developed to make the building blocks,” he says. Membrane boosts ethylene production A ceramic membrane may revolutionize ethylene production, hope researchers at Argonne National Laboratory, Argonne, Ill. The material enables ethane to be dehydrogenated without contact with air, notes Balu Balachandran, a senior ceramist at the lab. Instead, the released hydrogen passes through the membrane and then reacts with oxygen in the air. This offers a number of important benefits, Balachandran explains. Because the dehydrogenation reaction occurs without air present, it doesn’t yield byproducts generated by conventional steam pyrolysis — greenhouse gases like carbon dioxide, carbon monoxide and nitrogen oxide. Avoiding such byproducts pares pollution as well as simplifies product purification, he notes. In addition, the passage of hydrogen through the membrane keeps the reaction from reaching equilibrium, driving the formation of more ethylene. “We are essentially confusing or cheating the thermodynamic limit,” he says. Meanwhile, the oxidation of the hydrogen on the other side of the membrane provides enough heat to sustain the hydrogenation reaction, so external fuel only is needed for start up. “This is a clean, energy-efficient way of producing a chemical that before required methods that were expensive and wasteful and also emitted a great deal of pollution,” he says. The membrane is a proprietary dense high temperature ceramic, notes Balachandran. While he won’t divulge its composition, he does say that it can be made via routine fabrication techniques. Commercial units might resemble shell-and-tube heat exchangers, he believes. The development is at the infancy stage, though, he stresses. So far Balachandran and his team only have conducted laboratory experiments using a small button-type membrane. He hopes to create a tubular version of the membrane if he can get funding to extend the project. Some companies involved in ethylene production already have contacted him. Tiny sensor detects hazardous chemicals A sensor the size of a computer mouse that incorporates a gas chromatograph (GC) and a mass spectrometer (MS) will detect minute amounts of hazardous gases more quickly than possible with current technology, say its developers. Shrinking the size of the sensor enhances sensitivity while also cutting power consumption, notes Akintunde Ibitayo Akinwande, a professor of electrical engineering and computer science at the Massachusetts Institute of Technology, Cambridge, Mass. He is part of an international team involved in the effort that includes scientists from Cambridge University, Cambridge, U.K., the University of Texas at Dallas, Clean Earth Technology, North Ferrisburgh, Vt., and Raytheon, Waltham, Mass. Currently available portable GC-MSs are about the size of a full grocery bag, consume about 10,000 joules and take about 15 minutes to produce results, say the researchers. In contrast, the new unit consumes only about four joules and yields results in about four seconds, they note. Moreover, the small size means that the sensor should be able to be produced precisely and inexpensively via microfabrication techniques. The team aims to have the device completed in two years. Eventually, it plans to build a detector the size of a matchbox. CP www.chemicalprocessing.com How has technical staffing at your site changed in the past year? 40 Responses (%) 30 20 10 0 Increased Increased signiﬁcantly somewhat Remained the same Decreased somewhat Decreased signiﬁcantly More respondents reported technical stafﬁng increases than decreases. To participate in this month’s poll, go to ChemicalProcessing.com. 14 • March 2008 http://www.chemicalprocessing.com http://www.chemicalprocessing.com

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Chemical Processing - March 2008 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor Distillation is Bubbling Feel Secure About Vulnerability Assessments The Door Opens For Membranes Achieve Effective Heat Exchanger Control Epoxy Maker Finds the Right Glue for Its Business Process Puzzler Plant InSites Equipment & Services Product Spotlight/Classifieds Ad Index End Point

Chemical Processing - March 2008

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