The use of pigs in the Samarco pipeline to allow transportation capacity rehabilitation and integrity programme implementation

Transcription

1 Syopsis The use of pigs i the Smco pipelie to llow tspottio cpcity ehbilittio d itegity pogmme implemettio by J.C.M. de Souz* The Smco pipelie, the logest i the wold fo io oe sluy tspottio, stted opetio i 1977 to tspot cocette fom the Gemo fcilities, i the stte of Mis Geis, to the pelletizig plt, locted 396 km wy, i the stte of Espiito Sto, o the south-est cost of Bzil. Desiged fo omil cpcity of 12 millio tos pe ye, the pipelie eched 15.5 millio/ye due to opetiol impovemet d, i lte 2005, it ws esized to tspot 16.5 millio tos pe ye, with the istlltio of booste sttio. I ode to esue the ccute pefomce of the system, pipelie cleig pogmme ws cied out d, sice it hs bee 29 yes fom the opetio stt-up, pecise kowledge of the pipe coditio would be fudmetl to gutee the success of the poject. The cleig pogmme demostted the potetil of opetiol gis fom this iititive, d its effect o the coosio cotol d futue mesues, which should be pemetly dopted to miti the impoved cpcity. The itelliget pig us povided essetil dt used to estblish pipelie itegity pogmme tht llowed Smco to develop pipe epi pl bsed o the seveity d sigificce of the fetues d to implemet futue pipe eplcemet pl. Itoductio The Smco pipelie wet ito opetio i 1977, cyig the io oe cocette poduced t the Gemo fcilities i Mis Geis to the pelletizig plt i Pot Ubu, Espíito Sto, ove distce of 396 km. Desiged fo omil cpcity of 12 mtpy, the system eceived seies of impovemets util it ws ble to ech thoughput of 15.5 mtpy. At the ed of 2005, ew booste pump sttio ws dded to the pipelie system, icesig its tspottio cpcity by oe millio tos pe ye. The sizig of the ew system cosideed tht the pipelie would opete t full cpcity fte the booste sttio ws i plce, both i tems of pessue d flow. I ode fo these equiemets to be met, poject ws developed to ehbilitte the tspot cpcity d sceti the ctul coditio of the pipelie i tems of we due to bsio d coosio. This poject ivolved the use of cleig pigs s well s itelliget pig. The booste sttio poject Ude oml opetig coditios, the dischge pessue t Pump Sttio 1 (PS1) eched vlues close to the mximum llowble pessue. O the othe hd, Pump Sttio 2 (PS2) ws ot opetig t mximum pessue, idictig the possibility to icese flow te. Howeve, s the two pump sttios opete i seies, y dditio to PS2 would lso esult i dditiol flow t PS1. As the ltte ws ledy opetig close to its mximum pessue, the oly possible ltetive fo ddig thoughput to the system ws to istll ew pump sttio befoe PS2, t lowe level, educig the dischge pessue o PS1. I ode to icese the flow te t the pump sttios, the pump ge boxes wee eplced, povidig ew eductio tio. Thee ws o eed to eplce the electic motos, sice they hd eough powe to cope with this icese. The booste sttio cosists of two tis of two cetifugl pumps i seies, oe opetig, d oe stdby. Figue 1 shows the hydulic gdiet lie of the ew cofigutio. The tspottio cpcity ehbilittio pogmme The tspottio cpcity ehbilittio pogmme ws developed s esult of the eed to icese the compy s poductio te d fom the opetig evidece of the decese i the system flow te. * Smco Mieção SA, Bzil. The Southe Afic Istitute of Miig d Metllugy, SA ISSN X/ This ppe ws fist published t the SAIMM Cofeece, Hydotspot 17, 7 11 My T s c t i o P p e The Joul of The Southe Afic Istitute of Miig d Metllugy VOLUME 107 REFEREED PAPER JUNE

2 The use of pigs i the Smco pipelie to llow tspottio cpcity Smco Pipelie Gde Lie with Booste Sttio msl 1200 PUMP STATION PUMP STATION 2 BOOSTER STATION VALVE STATION 1 VALVE STATION 2 TERMINAL Km Figue 1 Hydulic gdiet fte ew booste sttio dded upstem of PS2 Histoy of occueces Duig the developmet of the booste sttio poject, icese i the dischge pessue of Pump Sttio 2 ws oted, d the followig possible esos wee cosideed: Chges i the chcteistics of the tspoted sluy Existece of pticle depositio i the pipelie Occuece of cceleted coosio pocesses Pesece of scle o the wlls of the pipelie Combitio of fctos. Figue 2 shows the icesed dischge pessue i PS2. Chges i the chcteistics of the tspoted sluy A itesive pogmme of smplig, tests d studies of histoicl dt ws cied out to evlute whethe chges occuig i the vibles could be ffectig the behviou of the sluy duig tspot. I spite of some modifictios i the cocette poductio pocess, which led to slight coseig of the pticles, o sigifict occuece ws foud tht would expli the chges i the pumpig behviou. Existece of pticle depositio i the pipelie Eve though o sigifict vitios wee foud i the chcteistics of the cocette, the deposits of cose pticles wee cosideed s pobble cuse fo the icese i pessue. These deposits occu mily i the lowe poits of the pipelie. Ay chges i the poductio pocess d mielogicl chcteistics of the oe pticles could chge the behviou of the fluid duig pumpig. Additiol studies wee doe to evlute this possibility. seemed stge, howeve, ws the fct tht this ppeed to occu dowstem fom PS2, i.e., 150 km fte the lime dditio poit. A expltio fo this could be the fomtio of clcium cbote scle o the wlls of the pipe esultig fom the dditio of se wte to the pumps d the etio of the sluy i the sttio stoge tk. Combitio of fctos Afte evlutig ll of the pobble cuses peviously outlied, it ws cocluded tht the most pobble cuse ws combitio of coosio with the pesece of clcium cbote scle d depositio of cose pticles. The use of cleig pigs Sice the most pobble cuse hd bee defied, the ext step ws to evlute the vilble ltetives fo elimitig the poblem, d the most suitble solutio foud ws the use of cleig pigs. The developmet of this poject ivolved sevel phses, s descibed below. Adpttio of the existig fcilities The Smco pipelie ws desiged to llow the use of cleig pigs. Howeve, the fcilities hd bee sized fo the of use fom pigs, which wee ippopite to solve the cuet poblem. All of the luches d eceives t the sttios hd to be esized d modified to llow fo the use of ew tools. Occuece of cceleted coosio pocesses I view of the fct tht the hed loss icese ws foud to be moe sigifict i the sectios close to PS2, oe of the most pobble cuses cosideed ws the pesece of cceleted coosio pocess. Pesece of scle o the wlls of the pipelie Due to the dditio of lime i the sluy to cotol ph, it ws thought thee could be sclig o the pipe wlls. Wht Figue 2 PS2 dischge pessue 386 JUNE 2007 VOLUME 107 REFEREED PAPER The Joul of The Southe Afic Istitute of Miig d Metllugy

3 The use of pigs i the Smco pipelie to llow tspottio cpcity Selectio of sevice supplies Oe of the difficulties foud duig the desig phse ws selectig supplies of cleig pig sevices, s oe of the fims cosulted hd y expeiece with io oe sluy pipelies. Afte suitble supplie ws idetified, the phses of the cleig pocess wee estblished: Idetifictio of the most dequte tools Developmet of the u pl Estblishmet of gols Estblishmet of smples, collectig pl to cofim the effectiveess of the cleig pocess. Figue 3 shows some of the types of pigs used i the us fom Pump Sttio 2 d the Temil. Executio of the cleig pogmme The cleig pogmme ws cied out i two septe phses: The fist phse ws i 2004, with us betwee PS1 d VS1 The secod phse ws i 2005 d 2006, i peptio fo the itelliget pig us. Afte seies of us ws pefomed, it ws cocluded tht the most suitble sequece would be s follows: Ivestigtio sigle pig, with clipe plte, without bits Smooth emovl double pig, i the cofigutio disc/cup/disc/cup/bits, with the bits djusted to 100% cotct with the itel wll of the pipe d low ttck pessue Tspot double pig cofigued with disc/cup/bush/ disc/cup/mget. Wheeve possible, use the jet spy optio to impove the pefomce of the ssembly Aggessive emovl double pig, i the cofigutio disc/cup/ disc/ cup/ bits. The bits must be djusted to 100% of cotct with the itel wll of the pipe d pogessive ttck pessue Tspot sme cofigutio s outlied bove Repetitio of the sequeces util the hed loss eched the estblished vlues. Pefom t lest two us i the ggessive cofigutio, with mximum djustmet of ttck pessue. These lso hve the fuctio of ectify/buishig the iside wlls of the pipes Afte the fist cleig phse, the subsequet us would pefebly be cied out with pigs cofigued without hd coted bits, i ode to peseve the ticoosio potective cotig. The pig us Duig the us, smples wee collected to evlute the mteil emoved d tspoted. These smples eveled the followig: Isigifict pesece of clcium cbote Sigifict qutity of biogeic mgetite, idictig occuece of micobiologicl coosio Pesece of cose pticles tht hd settled log the pipelie due to upled vitios i the poductio pocess, low efficiecy of the potectio systems, d possible chges i the mielogicl chcteistics of the pocessed oe Bsed o these fidigs, it ws cofimed tht bcteiologicl coosio isig fom the dditio of se wte to the mi pumps d the pesece of cose pticle deposits wee the udelyig cuses of the poblem. Figue 4 shows exmples of the mteil collected duig the us. T s c t i o P p e Figue 3 Types of cleig pigs Figue 4 Smples of mteil collected The Joul of The Southe Afic Istitute of Miig d Metllugy VOLUME 107 REFEREED PAPER JUNE

4 The use of pigs i the Smco pipelie to llow tspottio cpcity Figue 5 Smples of uusul objects Uusul fidigs I dditio to the expected mteils metioed bove, vious tmp items, such s scews, bolts, beig oute ig, file, gidig medi, vey cose pticles, gte of vlve, etc. wee collected fom the pipelie. These c oly be explied by opetig ccidets occuig ove the life of the system. Figue 5 shows exmples of these smples. Results obtied The cleig pogmme showed the possibility of: Removl of coosio poducts dheed to the pipe Removl of existig scle Removl of cose pticles d mteils settled o the bottom of the pipe Reductio i the hed loss s esult of the itel cleig of the pipes Icese i the flow te of the system due to the eductio of the hed loss. Figue 6 shows the eductio i the hed loss fte the cleig phses wee completed. Pecutios Afte the coclusio of the cleig phses, some pecutios hd to be tke to ssue cotiutio of the beefits obtied. Coosio cotol Pipelie mechicl cleig pocesses c ectivte d eve ccelete coosio pocesses tht wee peviously stble, s esult of the emovl of the fomed coosio lye, which cts s potective cotig. I ode to keep itel coosio ude cotol, the followig mesues wee dopted: Afte the emovl of the lyes tht dheed to the pipe, the subsequet us hd to be executed with pigs cofigued so s ot to emove y moe of the coosio film tht hd fomed, povidig cotolled potectio of the pipe Ivestigtio, chcteiztio d qutifictio of the bcteil coloies peset i the sel wte smples. Afte seies of smpligs d lyses, it ws foud tht the mi bctei peset wee io-educig bctei Idetifictio of the most suitble egets (biocides) to ihibit the ctio of the bctei. Lbotoy tests cofimed the possibility of usig biocides Estblishmet of pogmme to cotol the effectiveess of ddig biocides, cosistig of the peiodic collectio of smples t pedefied poits, upstem d dowstem fom the dditio poit, d coutig of the bctei, i ode to cofim effectiveess d y equiemet of djustmets i the dose of egets Idetifictio d istlltio of test specimes to cotol coosio (biocoupos) Moitoig of potetil eviometl impcts cused by the dditio of the biocide. Smples collected t sevel poits idicted degdtio of the poduct duig pumpig, thus ot pesetig y isk of eviometl impct t the ed of the pocess. Cotol of cose pticle dditio Sevel smples collected showed the pesece of much cose pticles th llowed fo the pipelie, which poited to the low efficiecy of the potectio scees istlled i the cocette poductio pocess (2 mm scees) d low etetio cpcity of the chge pump filtes (6 mm scees). The followig mesues wee dopted to miimize cose mteils i the pipelie: Implemettio of stict mitece pl fo the potectio scees Resizig of the chge pump filte scees Istlltio of filtes o the wte pocess pumps t PS2. Futhemoe, study pogmme cuetly udewy seeks to elte the mielogicl chcteistics of the cuetly poduced cocette to the occuece of deposits duig pumpig. Figue 6 Hed loss eductio 388 JUNE 2007 VOLUME 107 REFEREED PAPER The Joul of The Southe Afic Istitute of Miig d Metllugy

5 The use of pigs i the Smco pipelie to llow tspottio cpcity Coclusios Afte sevel us pefomed with wide viety of cleig pigs, the followig c be cocluded: It is pefectly fesible to dopt cleig pogmmes to miti the system s tspot cpcity The selectio of the type of tool d its degee of ggessiveess deped o the itel coditio of the pipelie Scpe pigs should be cofigued so s to ectify o buish the oughess o the wlls of the pipe. This is mde possible with the doptio of bits coted with tugste cbide o with simil mteil, distibuted so s to hve cotct with 100% of the ie wll Afte echig the desied cleig level, mitece should be cied out with less ggessive pigs, without usig bits, keepig potective ticoosio cotig iside the pipe Stict cleig pogmmes demd stict subsequet coosio cotol. The itegity pogmme Bckgoud The ttimet of opetiol esults ws bsed o two mi vibles: complice d itegity. The pefomce idicto Avilbility ws used fo complice cotol. The pipelie itegity pogmme ws bsed o edigs of pipe wll thickess t 119 poits distibuted log its legth. Due to ufoesee ccidets tht occued betwee cotol poits tht showed oml we mesuemets, this method poved to be ieffective. It ws the decided to use itelliget pigs to detemie the el coditio of the pipelie, focusig mily o loclized defects d thickess eductio due to bsio. The mesued idictos show the success of the ppoch of the bove fctos. Recetly the pefomce idictos stted to be iflueced by the followig poblems tht equied specil ttetio: Ccks o the mi pump fmes, cused by ftigue d ed of useful life Pefomce eductio of some spe pts Pipelie lekge. I ode to solve the poblem of fme ccks, eplcemet pl ws developed s fudmetl pt of the pipelie itegity pogmme. The spe pts pefomce is beig ivestigted with the soucig of ew supplies d mteils tht will fom itegl pt of the system mitece outie. The eoccuece of lekges must be stopped with the doptio of ew pipelie itegity pogmme. Figues 7 d 8 show the chge of the Avilbility d MTBF fctos. Selectig the ppopite itelliget pig techology The equiemets tke ito ccout i the selectio of the ppopite techology wee the followig: Sufficiet sesitivity to idetify defects povoked by itel d extel coosio, loclized o geelized, s well s we due to bsio Cpbility to detemie the esidul thickess of the pipe Possibility of usig without sigifictly ffectig the opetig outie of the system. T s c t i o P p e Complice d elibility Sice the ely opetio of the pipelie util ecetly, vilbility ws the oly impott idicto used fo complice with estblished gols. Sice 2003, elibility idicto ws lso dopted, mely MTBF (me time betwee filue). This, i cojuctio with vilbility, is bette epesettio of the system opetiol pefomce. My fctos ffect these idictos d the most sigifict oes e the followig: Itevetio plig The coective, pevetive d pedictive mitece itevetios should be pled so s to gutee thei dequte executio. The key poit is to kow exctly wht, how d whe to do Spe pts pefomce I ode to chieve good pefomce, the developmet of dequte mteils, compoets mufctue/ecovey methods d supplies is fudmetl. Pedictbility The kowledge of the coditio of equipmet d fcilities is lso fudmetl fo complice with the expected esults. Figue 7 Avilbility Figue 8 MTBF The Joul of The Southe Afic Istitute of Miig d Metllugy VOLUME 107 REFEREED PAPER JUNE

6 The use of pigs i the Smco pipelie to llow tspottio cpcity Afte evlutig the vilble techologies (mgetic flux lekge MFL d ult sc wll mesuemet USWM) d cosideig the equiemets bove, the USWM optio ws selected. Tble I Numbe of fetues Difficulties ecouteed The selectio d pplictio of the USWM tool peseted some difficulties, which demded specil ttetio to the plig d executio of the pogmme: Results Noe of the supplies hd expeiece i pefomig sevices o io oe cocette sluy pipelies d thei estimtio of the equied umbe of cleig us d the level of thei effectiveess ws empiicl tsk The tspot velocity of the tool ws impott pmete i the cotol of the us. The lowe the speed, the gete the pecisio i its edigs. Howeve, s the pig ws tspoted i btch of wte, sigifict eductio i the speed could esult i the depositio of solid cocette pticles, i dditio to ffectig compy poductio The cotol of the pumpig pessue duig the istumeted pig us lso equied some chges i the opetig outie i ode to meet system equiemets d llowble pig pessue equiemets. I ode ot to ovely compomise the poductio schedule, ctivities betwee PS1 d PS2 hd to be iteupted d wee escheduled fo lte The esults of the us mde fom PS2 to the temil e outlied i Tble I. The epoted defects wee clssified cosideig the ERF (estimted epi fcto) d WTDP (wll thickess depth pek), bsed o ANSI/ASME B 31.G clssifictio, s show i Tble II. Tble II Clssifictio of defects The pipelie itegity pogmme Bsed o the dt gtheed, itegity pipelie pogmme ws developed tht cosideed the mi topics listed below. Repiig defects The epoted defects wee teted ccodig to the flowcht i Figue 9 tht pioitizes the sequece of epis ccodig to how citicl they e. Immedite epis The defects clssified s ERF 1 d/o WTDP 30% wee epied immeditely with the pplictio of welded sleeves. Due to the high te of defects foud i the fist few kilometes fte PS2, the decisio ws mde to eplce 2.1 km of pipig i tht sectio. Figue 9 Flowcht: tetmet of defects 390 JUNE 2007 VOLUME 107 REFEREED PAPER The Joul of The Southe Afic Istitute of Miig d Metllugy

7 The use of pigs i the Smco pipelie to llow tspottio cpcity Tble III shows the umbe of epis mde. Figue 10 povides exmples of epis. Scheduled epis Defects tht wee ot teted ccodig to the citei dopted bove wee clssified ccodig to thei citiclity, esultig i epi pl fo shot, medium d log tem. Citiclity is clculted usig the fomul: Citiclity (C) = Seveity (SEV) x Sigificce (SIG) Fo the clcultio of seveity d sigificce, the followig citei wee dopted: Seveity seveity is fuctio of defect mgitude d edigs pecisio, weighted ccodig to thei elevce, followig the sequece: - Relevce of defects (RD) ws detemied usig Tble IV - The mgitude (Mg) of the metl loss defects (ERF d WTPD) ws detemied fom Tble V - The mgitude (Mg) of the lmitio d det defects ws detemied s show i Tble VI - The pecisio of the edigs mde by the US pig is fuctio of the pecetge of the echo loss: the gete the loss, the lowe the pecisio. The clssifictio of pecisio is give by Tble VII, which estblishes the tolece ges fo echo loss - The seveity (SEV) of the defect ws the clculted by the followig fomul: SEV = (Mg x RD) + (Pe x RD) Sigificce sigificce is fuctio of the impct tht lekge cused by defect could povoke. I this cse, the socio-eviometl impcts s well s the impcts o poductio e tke ito ccout. I clcultig sigificce, oe cosides the elevce d mgitude of the impcts, detemied ccodig to the followig method: - Relevce of impcts (RI) ws clculted usig Tble VIII. - The mgitude of the impcts (MgI) ws clculted usig Tble IX. - The sigificce (SIG) of the impcts ws the clculted by pplyig the followig fomul: SIG = MgI x RI The poits ddessed by the bove-metioed method e the pioitized d distibuted ito shot, medium d log ge itevls fo epis. Figue 11 shows exmple of the distibutio of the poits i the sectio betwee PS2 d VS1. The esults plotted i the gph epeset ovelppig poits with the sme clssifictio Tble III Repis Tble IV Relevce of the defect d edig pecisio Tble V Mgitude metl loss Tble VI Mgitude det d lmitio T s c t i o P p e Figue 10 Exmples of epis The Joul of The Southe Afic Istitute of Miig d Metllugy VOLUME 107 REFEREED PAPER JUNE

8 The use of pigs i the Smco pipelie to llow tspottio cpcity Tble VII Pecisio The defects elted to itel coosio wee teted i ccodce with the ltest evisio of Code ASME B 31.G. Lmitio d dets will be teted septely. Pl fo ew itelliget pig us The secod phse of the pogmme povides fo the pefomce of ew istumeted (smt) pig us sttig i 2008 to evlute the effectiveess of the mesues dopted d collect ew dt. The fequecy of the us will be detemied by these fidigs. The use of tools with the techologies such MFL, USWM, ietil d to detect ccks will be cosideed. Tble VIII Relevce of impcts Tble IX Mgitude of impct Moitoig of the extel cotig d cthodic potectio As most of the defects foud wee extel, due to flws i the extel cotig of the pipelie d i the cthodic potectio, systemtic moitoig pogmme will be put i plce. The moitoig pogmme will ivolve mppig tests (pipelie cuet mppig PCM d close itevl potetil puvey CIPS) evey two yes, sttig i 2007, i dditio to outie qutely ispectios. Aothe impott poit is tht, lso sttig i 2007, the moitoig of the pipe-to-soil potetil of the cthodic potectio c be pefomed olie, with the istlltio of optic fibe log the pipelie fo dt commuictio. Coclusios Plig of futue pipe eplcemet Bsed o the mximum llowble pessue clculted fo the cuet pipe wll thickess mesued by the US pig d o the we te pojectios, pl ws developed fo futue eplcemet of pipes betwee Pump Sttio 2 d the temil. I view of the legth of opetio of the Smco pipelie d the occuece of ufoesee evets, the use of istumeted pigs fo obtiig moe ifomtio bout the coditio of the pipe seemed to be the most ecommeded ltetive fo the developmet of system itegity pogmme. The esults chieved so f hve fully met expecttios. The dt collected hve llowed the idetifictio of wek poits d the executio of the ecessy immedite epis, i dditio to povidig gete pedictbility fo futue ctios. Figue 11 Seveity d sigificce 392 JUNE 2007 VOLUME 107 REFEREED PAPER The Joul of The Southe Afic Istitute of Miig d Metllugy