?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F187%2F&rft.title=In-Situ+Thermal+Remediation+of+Contaminated+Soil&rft.creator=Huang%2C+Huaxiong&rft.creator=Lapin%2C+Serguei&rft.creator=Westbrook%2C+Rex&rft.subject=Energy+and+utilities&rft.description=Recently%2C+a+method+for+removing+contaminants+from+soil+(several+meters+under+the+ground)+has+been+proposed+by+McMillan-McGee+Corp.+The+process+can+be+described+as+follows.+Over+a+period+of+several+weeks%2C+electrical+energy+is+introduced+to+the+contaminated+soil+using+a+multitude+of+finite+length+cylindrical+electrodes.+Current+is+forced+to+flow+through+the+soil+by+the+voltage+differentials+at+the+electrodes.+Water+is+also+pumped+into+the+soil+via+the+injection+well+and+out+of+the+ground+at+the+extraction+well.+The+soil+is+heated+up+by+the+electrical+current+and+the+contaminated+liquids+and+vapours+are+produced+at+the+extraction+well.+The+temperature+of+the+contaminated+soil%2C+during+the+process%2C+is+believed+to+reach+the+maximum+value+(the+boiling+temperature+of+water).+Normally%2C+the+electrodes+are+placed+around+the+contaminated+site+and+the+extraction+well+is+located+in+the+centre+of+the+contaminated+region.+The+distance+between+the+electrodes+is+usually+seven+to+eight+meters.+The+distance+between+the+extraction+well+and+an+electrode+is+about+four+meters.+The+diameter+of+the+electrodes+is+0.2+meter+and+the+extraction+well+is+0.1+meter+in+diameter.%0A%0AThe+reason+for+using+the+electrical+current+is+that+%E2%80%9Cflushing%E2%80%9D+the+soil+using+water+alone+is+not+effective+for+removing+the+contaminants.+By+heating+up+the+soil+and+vaporizing+the+contaminated+liquid%2C+it+is+anticipated+that+rate+of+extraction+will+increase+as+long+as+the+recondensation+is+not+significant.+A+major+concern%2C+therefore%2C+is+whether+recondensation+will+occur.+Intuitively%2C+one+might+speculate+that+liquid+phase+may+dominate+near+the+injection+well.+Moving+away+from+the+injection+site+towards+the+extraction+well%2C+due+to+the+combined+effects+of+lower+pressure+and+higher+temperature+(from+heating)%2C+phase+change+occurs+and+a+mixture+of+vapour+and+liquid+may+co-exist.+There+may+also+be+a+vapour-only+region%2C+depending+on+the+values+of+temperature%2C+pressure%2C+and+other+parameters.+In+the+two-phase+zone%2C+since+vapour+bubbles+tend+to+rise+due+to+the+buoyancy+force%2C+and+the+temperature+decreases+along+the+vertical+path+of+the+bubbles+out+of+the+heated+region%2C+it+is+possible+that+the+bubbles+will+recondense+before+reaching+the+extraction+well.+As+a+consequence%2C+the+probability+exists+that+part+of+the+contaminants+stay+in+the+soil.+Obviously%2C+to+predict+transition+between+single-phase+and+two-phase+regions+and+to+understand+the+transport+phenomenon+in+detail%2C+a+thermal+capillary+two-phase+flow+model+is+needed.+However%2C+to+simplify+the+problem%2C+here+we+only+consider+the+case+when+two-phases+co-exist+in+the+entire+region.&rft.date=2003&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F187%2F1%2Fmcmillan.pdf&rft.identifier=++Huang%2C+Huaxiong+and+Lapin%2C+Serguei+and+Westbrook%2C+Rex++(2003)+In-Situ+Thermal+Remediation+of+Contaminated+Soil.++%5BStudy+Group+Report%5D+++++