Rotameters in an Olefins Pyrolysis FurnaceReplaced with Micro Motion R-Series Meters

CHEMICAL

RESULTS•$384,000peryearinproductionsavings

•$92,000peryearinmaintenancesavings

•Paybackinlessthansixmonths

APPLICATIONInanolefinspyrolysisfurnace,ahydrocarbonfeedstock/steammixtureispumpedthroughamazeof4to6-inch((DN800toDN1000)diametertubeswhereitisheatedto815-885°C(1500-1600°F).Duringthecrackingprocess,undesirableby-products,includingmethaneandcoke(carbondeposits),areproduced.TheobjectiveoftheprocessistobeasselectiveaspossibletowardsEthylene,makingasmuchofthatmoleculeaspossible,whileminimizingtheproductionofby-products.Evenwiththebestcontrolschemes,cokeisstillproducedanddepositedontheinsideofthetubes.Thiscokeactsasaninsulator,preventingthefeedstock/steammixturefrombeingheatedenoughforthecrackingprocesstoworkandtheunithastobefrequentlyshutdownforde-coking.Toadequatelyde-cokeafurnace,thehydrocarbonfeedisreplacedwithairandmixedwithsteam,thenfedthroughthetubes.Bothsteamandairflowsshouldbemeasuredtoproperlyratiothecomponentsforefficientde-coking.

CHALLENGEAlargepetrochemicalcompanylocatedinsouthTexashasmultipleolefinsfurnacesthatusedrotameterstomeasuredecokingairfeed.Thecompanyneededtokeepthetubesfromcokinguptooquickly,preventfurnacetuberupture,andtominimizethedowntimerequiredtode-coketheunit.Thechallengewiththerotameterswasthatthemagnetusedtogeneratetheflowsignalwouldbecomecoveredwithdebrisfromtheairlinewhichnolongerprovidedanaccurateenoughflowsignaltoadequatelycontrolthedecokingprocess.

SOLUTIONThecompanychosetopurchaseMicroMotion®R-Seriesmeterswith1700transmitterstoreplaceeachrotameter.Thiswasacost-

AN-001863RevB/©2015MicroMotion,Inc.Allrightsreserved.

Formoreinformation:www.MicroMotion.com/chemicalwww.MicroMotion.com

EthylenePlant

CHEMICAL

effectivesolutionbecausetheMicroMotionmetersprovidedamaintenance-freeoptionwithamoreaccurateandreliableflowreading.Inoneyear,thecompanysaved$92,160inmaintenanceand$384,000inproductioncosts.

AN-001863RevB/©2015MicroMotion,Inc.Allrightsreserved.

BEFORE:RotameterInstallation AFTER:R-SeriesCoriolisMeter-ReducedMaintenanceandImprovedDecokeProcess

Coriolis Installation Costs

PipingMaterials&Modification

$30,000

Wire&Conduit $40,300

R-SeriesMeter $153,633

Total Installed $223,933

Coriolis Installation Savings

IncreasedProduction $384,000

DecreasedMaintenance $92,160

Total $476,160

Payback on Coriolis Meters

InstallationCost $223,933

AnnualSavings $476,160

Payback=Cost/Savings(Years)

0.46

Payback=Cost/Savings(Months)

5.64