Crude Oil Washing

Capt. A.K. Sharma- Ta Tankers nkers - COW -

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What is Crude Oil Washing? • The process of washing the tanks of a crude oil tanker with crude oil rather than with water as used to be done in earlier days.


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Let us now look at how this is achieved! Capt. A.K. Sharma- Ta Tankers nkers - COW -

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COW (COW) - WHY? •Increasingly restrictive legislation •Need to stop oil pollution completely •Oil industry stepped up its search or improved methods o cleaning tan!s" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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COW (COW) •#a$ority o oil tan!ers carry crude oil •Crude carriers - %iggest pollution threat" •International &greement &greement re'uired to stop all oil tan!ers carrying salt-ater %allast in cargo tan!s" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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Implicatins! ar reaching ery much higher transportation costs a)*rom reduced carrying capacity o individual oil tan!ers itted ith more segregated %allast tan!s" %)+,tensive modiication re'uired to %)+,tensive e,isting ships"


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Alternati#e cleanin$! • o o%tain Internatio International nal &greemen &greementt on such a controversial matter not easy • Idea as seriously considered %y I"#"O" • +arly ./012s oil companies commenced investigating investigati ng other alternatives" • Water -not a good cleaning agent or crude oil • & Solvent as re'uired" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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&'periments - (aptha cleanin$ • 3nder controlled conditions a series o e,periments ere conducted in &ru%a4 in the Netherland &ntillies" • &ter discharging discharging a cargo o crude crude oil4 the tan!s ere ashed ith Naphtha supplied rom shore4 %ut using the ship2s tan! cleaning machines"


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&'periments - Atmsphere Atmsphere cntrl cntrl • &tmosphere in each each cargo tan! as as monitored careully • 5ept over-rich or a%ove upper e,plosive limit4 • +nsuring that there as little or no ris! o an e,plosion or ire caused %y static or other actors"


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&'periments -res+lts • ery successul - clear indication that Naphtha as a much %etter cleaning agent than ater" • 6ro%lem - Naphtha is e,pensive4 not readily availa%le or cleaning tan!s on crude ships"


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,+rther &'periments • ried machine ashing tan!s ith actual cargo4 during discharge" • Not easy to persuade terminal and port authorities to permit the tan!s to %e ashed ith crude as the cargo as %eing discharged"


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,+rther &'periments • +vidence had to %e provided that the conditions governing such practices ere sae and the %eneits ere orthhile" • 7ue to careully monitored and controlled e,periments - current method o tan! ashing ith crude oil during discharge has %een accepted %y most oil terminals 8 port authorities4 8 approved %y I"#"O" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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9imiting Conditions or COW • 7evelopment o COW - gradual" • +'uipment o various types - tested4 approved or discarded hile results evaluated" • :loly it %ecame clear that crude ashing during the discharge as a ma$or %rea!through4 and gradually procedures ere developed4 accepta%le to %oth ship and shore authorities" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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9imiting Conditions or COW suita%le e'uipment re'uired • COW largely conined to ships itted ith suita%le e'uipment4 as ollos;.":hip must have an I< system and a%ility to control 8 limit O = in cargo tan!s" (upper limit o > is airly normal") Capt. A.K. Sharma- Ta Tankers nkers - COW -

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9imiting Conditions or COW suita%le e'uipment re'uired =" *i,ed-in-place machines4 mounted through the dec! ith suita%le no@@les or crude ashing4 and i,ed piping ith pumps mounted in the cargo pump room4 and not the engine room"


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9imiting Conditions or COW suita%le e'uipment re'uired A"&larms and monitoring m onitoring ail-sae devices must %e itted to ensure that the Inert

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COW Operation • #ain o%$ective o COW - to remove crude residue rom cargo tan!s • Besidue upto . o cargo loaded" • A114111 dt tan!er  A111 tons" • I COW eectively done4 BOD cut to around E11 tons4 (most entrapped in pipeline system and slop tan!s)" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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COW Operation • &t present COW not a complete su%stitute or ater ashing • 7oes not dispense ith 9"O"" i ater %allast is carried in crude tan!s or pumped through cargo piping"


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COW Operation • 9arge crude tan!ers itted ith I<: 8 closed loading 8 discharging systems need to have an individual chec! list to ensure all saety and monitoring e'uipment as ell as the actual pumping and cleaning e'uipment is or!ing eiciently and ree rom lea!s"


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COW Operation • *ailure o any e'uipment may $ustiy shutting don COW or saety or other operational reasons" • Numerous types o e'uipment 8 methods m ethods used to crude-ash individual ships" • aries considera%ly - ship 8 circumstances" • O"C"I"#"*" O"C"I"#"*" - hand%oo! hand% oo! called ca lled 2
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COW Operation • #ost popular method at the present time appears to divide COW o individual tan!s into to distinct phases" ." op ash (sometimes divided into to separate operations) =" Dottom Wash"


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COW Operation Top Wash • Commences hen tan! still one third ull" • 7ec! mounted machines turned on and e,posed areas o tan! ashed ith $ets o crude - pressure o .1-.= !gFcm = 4 according to the type and num%er o machines used" • +,posed areas let ith a thin ilm o crude4 Capt. A.K. Sharma- Ta Tankers nkers - COW -

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Full Cargo Tank discharge has coenced


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W"#$ T"# T%$& '( %)O*T "%LF #+,T- ,O/%++# +%C"'$#( FO+ 012O TO 32O


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COW Operation Top Wash • Clingage drops to tan! %ottom and is discharged ith the cargo ashore" • Normally a cargo pump is used to provide crude oil to the tan!-ashing machines" • an! ashing machines have an individual capacity o .E1 to .0E cu%ic metres per hour" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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COW Operation Bottom Wash • When oil in the tan! is airly lo4 %ottom ashing commences" • In some cases this involves using machines itted on mounts or platorms near the %ottom" • hese machines are normally su%merged hen cargo is in the tan!4


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W"#$ T"# T%$& '( %L+O(T #+,T- 4056+7 ,O/%++# +%C"'$#( FO+ 32O TO 82O


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W"#$ T"# T%$& '( #+,T,O/%++# +%C"'$#( FO+ 82O T TO O 2O


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COW Operation Bottom Wash • Dottom mounted machines are very useul4 not only to ash sludge o the tan! %ottoms4 %ut to reach areas o the tan! screened %y some structural mem%ers and rame rom %eing eectively cleaned %y the through-dec! mounted machines"


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COW Operation Bottom Wash • Dottom ashing depends largely on the %ottom %eing !ept uncovered so that the crude $ets can move the sludge" • :tripping must %e e eective ective 84 i possi%le4 should %e conducted %y use o one or more eductors driven %y a cargo pump" • he eductor ould normally discharge into one or %oth o the slop tan!s" • :lop tan! level - careully monitored" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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COW #achines • Not all i,ed-dec! or su%mergedmounted machines are suita%le or crude ashing" • #any o the older types have unsuita%le4 no@@les and are prone to lea! at glands and other ittings hen used or crude" • arious ma!es are in use"


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COW #achines Lavomatic Selective Arc T/C machine.

• :uita%le or crude and ater ashing" • *i,ed through-dec! mounting" • *itted ith a single no@@le on the end o the drop-pipe and operated %y a simple gear train"


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• #achine 8 drop-pipe can %e ithdran or maintenance through aperture in dec! • 7rivingFtiming mechanism mounted a%ove dec!" • Can %e porta%le or an integral part o each machine" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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• 6orta%le version can %e hydraulically or pneumatically driven" • *i,ed drivingFtiming mechanism is hydraulically operated" • 7rivingFtiming device - angle o no@@le on each machine can %e controlled or top ashing or %ottom ashing cycles Capt. A.K. Sharma- Ta Tankers nkers - COW -

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• &rc 8 radius o action should meet the re'uirements o the particular ash cycle" • 7epending on type o e'uipment used 8 si@e o ship4 as many as .11 machines may %e re'uired4 ith .1 - .E in any one tan! to clean a A114111-d""t" tan!er" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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T"# (%+# ,OC#(( ("O*L9 )# #,#%T#9 FO #%C" (*)(# (*) (#:*# :*#$T $T T% T%$& T"%T '( C*9# O'L W%("#9 Capt. A.K. Sharma- Ta Tankers nkers - COW -

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#+#+)# #+#+) # T"% T"%T T W%(" T'+ T'+'$ '$/( /( %$9 +%C"'$# ,O/%++# %$/L#( %# TO )# %( %( ,# T"# C*9 C *9# # O' O'L L W%(" ("'$ '$/ / +%$*%L +%$*% L OF T"# ("', Capt. A.K. Sharma- Ta Tankers nkers - COW -

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#/*L%T #/*L% T'O$( #:*' #:*'# # • %LL T% T%$&( TO )# )%LL )%LL%(T#9 %(T#9 %# TO )# C*9# O'L W%("#9 F'(T • TW#$T- F';# ,#C#$T ,# C#$T OF T"# T"# )%L%$C# T%$&( %# TO )# C*9# O'L O' L W% W%(" ("#9 #9 • %LL %LL T%$&( T%$&( TO )# W%(" ("#9 #9 %T L#%(T O$C# #;#- FO* +O$T"( +O $T"( Capt. A.K. Sharma- Ta Tankers nkers - COW -

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C*9# O'L T%$&# W'T" (#/#/%T#9 )%LL%(T T%$&( %$9 63 C.O.Ts.


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+%(T# 9#C'9#( 4%( #:*'#97 TO &##, 6C 1C %$9

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T"'( L#%;#( % )%L%$C# OF 6= C.O.Ts. OF W"'C" 61> %# %# TO )# C.O.Wed. C.O.Wed. i.e. T% T%$&(


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$#@T ;O-%/# T"# "#%;- W#%T"# )%LL%(T T%$&( ,L*( %$OT"# 61> OF T"# C.O.Ts. %# TO )# 9O$#


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% F*T"# 61> OF C.O.Ts ,L*( T"# "#%;W#%T"# )%LL%(T T%$&( W'LL )# C.O.Wed T"# FOLLOW'$/ ;O-%/#


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T"# L%(T 61> OF C.O.Ts ,L*( T"# "#%; "#%;W#%T"# )%LL%(T T%$&( W'LL )# C.O.Wed '$ T"# FO*T" ;O-%/#


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CO$9'T'O$( CO$9'T' O$( '$FL*#$ '$FL*#$C'$/ C'$/ COW #(*LT • +%C"'$# $*+)# LOC%T'O$ $OAAL# 9'%+#T# • W%("'$/ ,#((* ,#((*# # • *LL%/# W"#$ W%("'$/ (T%T#9 • W%("'$ ("'$/ / T'+# T'+# • +%C"'$# ,O/%++'$/ • (T',,'$/ #FF'C'#$C• 9%'$ "OL# LOC%T'O$ $*+)# ('A# • T'+ OF T"# ("', • C*9# O'L (,#C'F'C%T'O$( (,#C'F'C%T'O$( Capt. A.K. Sharma- Ta Tankers nkers - COW -

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&dvantages &dvanta ges o COW ." &s the tan!s are ashed ith cargo during dischargea) he crude oil residue let clinging to the shipGs side and internal mem%ers is reduced su%stantia su%stantially lly"" %) he %uild up o sludge and as in the tan! %ottoms is largely eliminated"


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&dvantages &dvant ages o COW COW ="+,perience has shon that cargo loss during tan!er transportation is reduced as a result o a comparison %eteen ships using COW and others cleaning conventional means" In other ords4 %y ashing ith crude oil during discharge4 more o the cargo discharged ashore and the individual tan!s are let a lot cleaner" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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&dvantages &dvantag es o COW A"an!s4 hich have %een ashed ith crude oil4 re'uire ar less cleaning and ater ashing4 either or clean %allast or or entry into a repair yard"


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&dvantages &dvanta ges o COW "9ess dirty %allast and ash ater are re'uired or COW4 so the potential or pollution is reduced during tan! cleaning at sea"


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&dvantages &dvanta ges o COW E"With less salt ater ashing4 steel corrosion ithin the cargo tan!s is reduced


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7isadvantages o COW here are three main disadvantages to COW as practiced at the present time." It does not entirely eliminate the need or ashing ith salt ater4 either or clean %allast or entering a repair yard" It also does nothing to clear and gas ree pipelines ithin the ship"


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7isadvantages o COW ="he need or ships to %e itted ith an inert gas system and i,ed ashing machines designed or crude ashing4 means that a lot o older and smaller ships are una%le to avail themselves or COW ithout ma$or modiication and e,penditure"


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7isadvantages o COW 3" COW -hen ship is discharging • #eans that normal discharge prolonged

• Whole ship COW - normal shore acilities discharge time  upto =E  o normal" • I COW rotational (CD J selected tan!s) this igure can %e reduced to appro," .1-.E o the normal discharge time4 • O%viously crude recovered ill %e less" Capt. A.K. Sharma- Ta Tankers nkers - COW -

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%9;%$T%/#( OF C.O.W. "'/"# C%/O O*T O*T55T*$ 9*# 9* # TOB

• L#(( CL'$/%/# L#(( (L*9/# 9#,O('T( #FF'C'#$T 9%'$%/# ;LCC #(T'+%T #(T'+%T#9 #9 .O.). %FT# 9'(C"%/#

•W'T"O*T COW 5 0222 +8 •W'T" COW

5 822 +8

)#$#F'T( #F'$##F'$#- ("',OW$# C"%T## Capt. A.K. Sharma- Ta Tankers nkers - COW -

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%9;%$T%/#( OF C.O.W. ,OLL*T'O$ %;O'9%$C# 9*# TOB

• L#((# O'L '$ 9#, 9#,% %T T*# *# )%LL%(T • L#((# W%T# W%("'$/ #$O*T# • $O W%T# W%(" FO (L*9/# CO$TOL • L#((# L#((# (LO, #CO;##CO; #- %T #$9 OF )%LL%(T ,%((%/# • )#$#F'T( #$;'O$+#$T OW$# #F'$#Capt. A.K. Sharma- Ta Tankers nkers - COW -

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%9;%$T%/#( OF C.O.W. L#((# (%LT CO$T%+'$%T'O$ 9*# TOBB TO

• #9*C#9 W%T# W%("'$/ T"##FO# L#((# (%L (%LT T '$TO9*CT'O$ '$TO9*C T'O$ '$TO T"# T% T%$&( )#$#F'T( C%/O #C#';#( #F'$#Capt. A.K. Sharma- Ta Tankers nkers - COW -

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%9;%$T%/#( OF C.O.W. • C%/O C%-'$/ C%,%C'T'$C#%(#9 "#$C# "'/"# F#'/"T #%$'$/( • )#TT# COO('O$ CO$TOL • #9*C#9 WO&LO%9 O$ )%LL%(T ,%((%/# • 9%(T'C #9*CT'O$ '$ 9-9OC& ,#,% ,# ,%%T %T'O$ 'O$ T'+# Capt. A.K. Sharma- Ta Tankers nkers - COW -

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? Only advantages Capt. A.K. Sharma- Ta Tankers nkers - COW -

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9'( 5 %9;%$T%/#( OF C.O.W. '$C#%(# '$ • 9'(C"%/# ,#'O9 • ,OT WO& LO%9 LO%9 • ,OLL*T'O$ '(&( • /%( /#$#%T'O$ • ,#((*# (*/# '(&( • (&'LL#9 +%'$T. #:*'#+#$T • #:*',+#$T CO(T( Capt. A.K. Sharma- Ta Tankers nkers - COW -

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Crude Oil Washing

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