Chemical Processing - July 2008 - (Page 50)

enD poinT Can Process engineers Tame Volcanoes? Macro-scale chemical engineering seeks to contain lava flow There are “perhaps 20” active volcanoes in the world at this moment and between 50 and 70 erupt each year according to the Global Volcanism Program at the Smithsonian National Museum of Natural History, Washington, D.C. We’ve all seen news reports of the devastation to lives and property these eruptions cause, but could macro-scale chemical engineering be used to stop a volcanic lava flow? That’s the intriguing question posed by Olaf Schuling of Geochem Research, Nieuwegein, the Netherlands, in the current issue of the International Journal of Global Environmental Issues. During the 1960s, Schuiling pioneered geochemical engineering, which involves using natural processes to solve environmental and civil engineering problems. He recently turned his attention to how to tame volcanic lava flows. However, in 1973 Iceland had some success slowing advancing lava from Heimaey by dousing the lava with huge volumes of seawater. Meanwhile in Sicily, Zafferana was saved from the 1991–1993 eruption of Etna by huge earth walls built to divert the lava flow. Schuiling believes a geochemical approach might control lava flows across the globe. Common rocks, dolomite, or limestone, react strongly with hot lava at 1,100ºC to 1,200ºC, he explains. The chemical reaction is highly endothermic, with the hot lava supplying the heat. The decarbonation of limestone by hot lava rapidly cools the volcanic outpourings, making it far more viscous and quicker to solidify. The reaction leaves behind solid calcium and magnesium oxide mixtures — pyroxenes or melilites depending on the type of lava. It also releases some carbon dioxide. Large chunks of dolomite or limestone blocks could be thrown on to lava from the sides, from above by helicopters, airplanes, or even by an aerial cable system passing over the flow, Schuiling suggests. An alternative is to quickly build a wall of limestone blocks in the path of advancing lava. Where a future lava flow would cause great material damage, such walls could be constructed as a forward defense before an eruption. For more, see “How to stop or slow down lava flows,” R.D. Schuiling, Intl. J. Global Environmental Issues, 2008, 8, pp. 282–285. Meanwhile an international team of scientists has concluded that drilling a gas exploration well — not an earthquake — prompted a mud volcano in Java. 50 Decarbonation of limestone by hot lava rapidly cools volcanic outpourings, making it far more viscous and quicker to solidify. The continuing, two-year-old eruption has displaced 30,000 people, caused millions of dollars of damage and is still spewing huge volumes of mud. The most detailed scientific analysis to date disproves that an earthquake two days before the mud volcano erupted in East Java, Indonesia, was the cause. The report by British, American, Indonesian and Australian scientists was published June 10 in the academic journal Earth and Planetary Science Letters. Lead author Professor Richard Davies of Durham University, Durham, U.K., published research in January 2007 that argued the drilling was most likely to blame for the May 29, 2006 Lusi mud volcano erruption. This theory was challenged by the company that drilled the well and some experts who argued that the Yogyakarta earthquake, which had an epicenter 250 km from the mud volcano, was the cause. Graduate student Maria Brumm and Professor Michael Manga of the University of California, Berkeley, Calif., studied the claims. They found that none of the ways earthquakes trigger eruptions could have played a role at Lusi. “In this case, the earthquake was simply too small and too far away,” explains Manga. The new report concludes the effect of the earthquake was minimal because the change in pressure underground would have been tiny. Instead, scientists are “99%” certain drilling operations were to blame. Professor Richard Davies, of Durham University’s Centre for Research into Earth Energy Systems (CeREES) explains that the day before the mud volcano started there was a huge influx of fluid and gas into the wellbore. “After that, pressure in the well went beyond critical, resulting in fluid leakage from the well and rock formations to the surface This fluid picked up mud during its assent and Lusi was born.” Chances of controlling this pressure would have been increased if there was more protective casing in the borehole. “We are more certain than ever that the Lusi mud volcano is an unnatural disaster and was triggered by drilling the Banjar-Panji-1 well,” Davies adds. Lusi is still flowing at 100 000 cubic metres per day, enough to fill 53 Olympic swimming pools every 24 hours. Seán oTTewell, Editor at Large sottewell@putman.net July 2008 chemicalprocessing.com http://chemicalprocessing.com

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Chemical Processing - July 2008 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor Who’s a Big Hit? Succeed with Condensate Control Take Some Basic Steps with pH Measurements Steam Projects Provide Fast Payback Process Puzzler Plant InSites Equipment & Services Product Spotlight/Classifieds/Ad-Lits Ad Index End Point

Chemical Processing - July 2008

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