European F e d e r a i i o n of Corrosion Publications
NUMBER 46
Amine unit
corrosion in
refineries
J . D. Harston and E Ropital
Puiilihhed far the Eurupean Federatiun of Cori'osion
hy Woodhcnd PubEshing and Mancy Publishing
on behnlf of
Tha Inslitute of Materia&, Minwcls & ivfining
Amine unit carrosion in refineries
R'cviKlhciid Piililidiin: Liiiiiird liid h4ilaiary Pi~htisliiit$i i ~ i i i i i don I>ciinlio l
Thc Iiisiiuiis: iif hl;tien;il~. iliillenk <* Miniiip
Piihiishcii Isy \\i(l~dilehlPUhli~hiti$1,irniiCd. h l i i ~ g i l l lHilll.
l
Bixnta Frirk.
G~eatAbii~gftin.C.!inhl.iJpc CH2I &AH. Ea$land
Contents
rrz~iu.w~~udhcii<lp~~hlisI~in~~~~~~~~
Piihli~hcdiir Norlh Atwriea by CRC P~ursI.LC. IiIIIU) I31.tikr.nSiiuiirl Rirkwiiy. NW.
Suiii ?IiO.r)rait Itiirin. b% >3JK7. USA
Piixst ~~ulilirlied
?i1117 l- Wqxidlirad l'tihiisltiii$ Linliircl i n i l C'IPC l',,.%v LL<'
RomIntid ZIiiX',
O 21x17. liiitiiiitr $>l
~ l ~ ~ l & r iMiiienl*
nlr.
B Minio?
Thr :~iiihbr$havc nssorlcd Ihcir ei<iial iipliis.
This h<ii,k ciiniiiiiir itt~<rrnwtli,ii
ohlaiia<lliriiii ;iciillcnrir uiiil biglily rc~~i.di.ilriumwcs.
Keprinied iinrr.ci:ii i8 yitoi+d iviili pi.niiie$ioii. sild wiourccs ore iiiiiliuitcd. Ilcasf~iiohlc
iifl<~.ts
h81vc hecn mi;>& io puhilsh rcli:il>lc dalii ;iiid iiihrmnrioii. hii il~r
ituihurr ;nid
Il>+
,>iihlishcrs cnnnril iinauiiii? rcspii~tsihililyfin' ibr validily al'nll ~ ~ l i ~ i ~ Neilhcr
iills.
li?<: auilii~rscnirr Ihi: ptihlirheis. i i < w noyiinr cbe i ~ ~ s i w b iwiih
i t l ilris piihliciiiiri$. sli;ill
hs lhhic Cr,r m y losi. dfti>iqctbr li;rhilily <lihrib; or iiirlircrily eaurcd i>,;tll$gcd 10k
~auscdhy tbis holik.
N~4ilbrrliir houk inor any liari niay h. mpvlxkiccii or IiiiiiiinilrLd lri atiy Ihrin ix hy
utry nrmiis. r.lrz.lriinie iir rner.h&~iic~l.
i!>cfiidin$ phaii?ct!yyino. micnii'ilrnici- and
rwordiitp. or by riiy iiil<irm;iIicm s<~>ru$i>
or rciricvril syslcni. wiilioul pcrii>ir%i;iiili
iii
r r i h g )ioni Ilic \U>oJhctd Puhlishing 1.imilul.
The cr>irsenlo i Wiiirdlrc~JVlllihli5hinp Limilcù Jocr ~ x icxlcnd
i
i k i clipying (#>igcner.il diririhiiliab. li, pii?m<iiion.li>rcrealici$ iii:ui <i.oi-k~iir iilr ms;tla Spci,iiir
prfmissiim I>IUSI
Ix: ~ ~hlilitltd
in w!iliii$ i n ~ nWtmlhcatl
i
Puhlishins Li~iiiwJliir r u d i
c,',pyine,
i+,lu,riu.r iri (/i< GFf .rortei
2 Teclinica1 baekground
I.I
2. I.?- Absurbcr
2.1.3
2.2
Ti-adeniaiQtiiiiicd: Prir~lui.1or c.i>qii>nltriiiimos Iiiay Ihe 1rudi;nrorL.a <ai. mgii;lcrr.d
wdniiririis. ilnd air irwd nlily Iilr idckiiiile:iiii,i; itiid iiipliiiiiiliiiti. w.irhn"l ii,icd li,
infringe.
2.3
Bdtiah Lihroiy CakliO$ui&l~
i t i Pilhliciii<iii mti;t
A~~ialtrgtic
acrirrt liir ihiu hiitik i r avililehle lilini ilr iilitirli Lihnu-g.
Lihritry i,I Ci>ngierrCwuli>&i$ in Wthlimtikin I).di~
A ciii.~lc>$
rar>iil li,, ~ l i i shiiiik is ~ i v ~ i l u bfmm
k ihc Lihmry iiiCtxiisrr.*r.
Wtlrnlhcatd Puhlirliin~ISBN U78-1-Xt569-231.7 lho«kl
W@>mlhci%l
Puhlishing ISBN 4%-I-NSh9-123-7 It-hiicbkl
CRC Prce ISBN Y78-I-??IUI-S4YS-8
CHC Prcs urdcr iii~ml>er:WiJSJ<)S
ISSN i?%-51 l 6
PmileJ m thc U n i m cd~lngdomh? Lighriiins Souwc LIR L R ~
Rogei~cwlo r
I m l x i r l ; i ~ ~issues
l
Cornisioil irsues
1.3.1
Oeneial f:3ci«rs
2.3.2 Mecl1:inisms
2.3.3 Rich amine
2.3.4
Lcaii ainiiit'
2.3.5 Acid Eas audck
2.3.6 Wcal-sr~~hlc
aniiilc salls
2.3.7
2.3.8
2.39
2.3.10
2.3.1 1
The ]ruhlisiu.n' poli- ir io i w pcrni.lncni p:<par hi~ii
ri~illsihiit irlmalr. a
ainainahl~.Cli>rcstl.ypiilicy, aiiii whicli has ho11 ina<i~ilirciuir.ri
i v i i i ~ vitili
i
which iiprocessd uiing neid-iwe iuid rletiicnwy cbliiriiir-trcc p>iciicer.
hiiihwiri*ire. ihc ~pi~hlirlii-n
ciisiim il~iii
ilu. irri Ipaycr an<l i.ovcr hoi;ilrl awd
Ihwr tu<
n~c~plllhll:
civironiiientiil itriwlilulii>niiit>d:iitir.
Pr»ccss i$suei
3.1.1
Pr&lwattncnl
2.3.12
2.4
3
blnke-up wwtei qvalitl'
Erosion cn.rc>sion
Prtiprioiary c l ~ e m i c acidditirins
l
Corn>sion in regencraiirr O V C ~ ~ I S U ~ S
Hydr«gcn-mlpW4 c c n c k i ~ii
i i~wei H'S syxtrms
Alkalinc stress cofrosioil c r a ~ k f i l ~
hluteriols
Expefiences of ieri p l a n t s using methyldiethanolamine
3.1
Gas compiisiiioil
3.2
Maicrials af c o n 6 t ~ ~ l i 0 n
vi
contenls
3.2.1
3.2.1
3.2.3
3.2.1
Cirbqiri riccls
Spcciill carhriii sic~l.:
Spcci-iiilriainlcss sicclb
Oucrliiys. cliidding iind cutiline
3.2..i Stress-mlicving pitlicy
3.3 0per:btiiig purtrmcierr.
3.:.l
Amine paniiiialew ii»d li>liininy!
3.33 Acid gnscs. h-,(-si;lhlc ilmine siills. \2sli9ciiies
stid rchoilw icmperalwn-s
1.3.3
Muke-iip \v&icr
3.3.4
Srilids p u m i aird filtruiirrii
3.3.5
lelkdgc.
à.3.6 liilci a
:s ki)i>ck-i,iil \'L.*scI
3.3.7 Dcsizn IBclors
1.4 Crrrrc>sionc<iiiiml
3.4.1
Treii~ments
3.4.2 Mirni1o1-in$
7 . 3 CT,nir<~l
paraincicn
3.5 C<irrnsii,ti ~mhlemsexpericli~%d
3.6 Suinmary (il:sclecled dava
4
Y
10
111
II
lI
II
5
~
~of four plants
~ using monoethanolamine
~
~
I4
14
15
17
19
?Il
1
?O
10
?I
22
3
6
2.5
Ih
36
36
27
~ ~f one piani
~ using diisopropanolanline
~
~
E
6.1
6.2
?Z
?:I
11.
25
25
26
~
~
~
~
5.2.1
Carhon steek
5.2.2
Special wrrlioli stels
5.2.3
Special stninlr6s sied3
&.IS
.
Overlnys* cliidding and c t l ~ i i ~
5.2.5
Stress-~elieulngpolic~
5 3 Ol~eralingpaT&illC?Ifr~
5.3.1
Amine p,arameieis and r»illnl~f$
i , j heal+taltlc aniitxc sdis. veli>cilics~ f i d
5.3.7 ~ ~ gt,rer.
rchuiier teinperaiurris
4.3.3 Diloke-up wster
5.3.4
S,>li&s prcscni iirid Filiraiii~i~
5.3.5
0: leakaac.
5.3.6
Inlet gas kn~rk-irU1
VCSS~~
5.3.7
Design faciars
4
Cr>rri~sioii
conlr*il
5.7.1
Ti'euiincntn
5.1.2 Mmirofiilg
5.4.3
Ci>nlrriI puraill~Lc.rs
5 .j Cnn~aioiiprohlm* eipcrienc~d
1'1
Gus cr,rny<aiiii>~i
Maicrials <il'u<inlrt&ctii~ir
4.2.1
Cdrli<riislcels
4.2.7 Sp~~iibL
CU~~CIII S \ W ~ S
4.2.3 Speci~dlsliiinlc+s sfccls
4.2.9 Ovcrlsya~claddirig aiid c~>iiiitig
4.2.5 Siiess-rclievirig polic)'
4.3 Opcmiing parnmelers
4.5. I Amiire piirurneiers imd l i i ~ i ~ i i i n g
4.3.2
Acid g&%ei.heni-atuhlc nmiiie siilin. velcxciliei .;riid
rehi3ile.r ternpsmtnmr
4.3.3
Makc-il{>woter
4.4
Snlids preL.sititnnti liltroii<iii
4.3.5
O? 1e;ikage
4.3.6
liilci gas kiliisli-nui resse1
4.7
Dcsign firc'ti~ri
4.4 C<irrt>sioiicrbnirnl
4.4. I Trwinreois
4.9.3
Moriiioriiig
4.9.3
Crrnin>tparnniclcrs
i
Gas ~ ~ i n i p u ~ i l i o i l
9.2 Msterisls (>l
cunsiructi~n
5.1
12
13
13
1.:
13
I4
14
16
4.2
C<irr<>sioii
p~obkmscnpcrlew'*
5 .
Findinys lot ~ c plAn1
h
I,L~caiioniil prohlcms p iiem VT ~ u i F n i ~ n L
4.3.2
IO
Experiences of wenfy-one plants using dietlianolamine
4.1
4.5
6.3
@s
;
ccofnp«siiion
Maieiilils r>F consrntciion
6.2.1 C a r h n steeis
6.2.2
Spxilil carbiin steek
6 . 2 2 Spccial sraiiiless steels
6.7.4
Overhys. clartdiiig und conling
6.3.5
Sttzss.retieving p l i c y
Opemting garaiiiBtC?rs
6.3.1
Aminc purnmeterew and fiUlnin!4
6.3.7 kiid giises. hmi-stah~ramiiie saiis. vcl<lcily R I * ~
rcimilcr ieniperulUl\:
6.3.3
Mnkc-iip waler
6.3.4
$(>lids preseni und f i t i ~ l i ~ n
6.3.5
Oileiikase
~
~
~
~
European Federa.tion of Corrosion (EFC)
publications: Series introduction
The EFC. i>icorporaiedin Belgiuhl; was fi>und&!in I955 with Lhe purptise of
pwmoiii]g Eiir(q>eunco-iipemtiiin i11tlie fields of rescarcb inlo c~lr1'0~loilmild
e~~t~,osiciii
prcventi~rti.
Memhersliip<iI'rheEFCi s hiised upon parlriicipatioii I>ycomision aiicieties
and c«miiiittees in IL'Liinical Woi.l<in&Pdriies. Mernlwr socielics aplmirii
delegotes I« Wclrkirig Parties, whose mllkrghip i$ expdndcll by persnnnl
ci>nes[iondingniemhcrshili.
Tho ;+ciiviiies"l' ihe W<>rkingkirtili~:cover ccin'esion iopics asuuciuted
wilh iiihihition, etluciitian. reinlbrccmciil in c»iicrcte, microhial &i'kcls. 1\01
31sss 2nd co~nhusiii>npruduers. cnvlroiinn;nl-reiisilivc fr~t.1ui.e~
marine
eiiviionmenis. rcl'inerie$. surf~ccscience, physic<i-cheniicnl meihods ol'
minsurctiionl, ~ h iluclmr
c
iiidustry. Ilio ~ul<iiiiiitivc
industry. coiiipi~tc~-l~~tsc.d
in~orinaliurifiystems. coaiiii&s~tribe-co>rrasionand Ihc oil md sas iiiidustry.
Wmltins Pwiic* siid Task Pwces oli other tupici am esrahlishcd as tquired.
The Wiirking Pnnics Iiiiiclitn in variouu wxys. e.g. hy prclioriing mp<wlS.
orguiiaing syniposia. mnductin@intensive coursos and producing ìn.urucri~imil
nxiierial. iii@liidingiilms. Thc aclivities ofWorking P;trti<^ian' co-~irdinaled.
ihrougb u Science 2nd T~!hi~>k>gy
AdviS«sy Cominiuoc. by lhe Scientitic
Secreisfy. The iidniiitistrt~tionof the EF-C is, h d l e d hy Lhrce Secretariat8:
DECHEh4A e.V. i n Germsny, Lhc S«ci&i€<leCbimie Inilustdelle in Frailce.
an,l 'lhc Inrliiiilr .,M:iicri3ls.
i
h.linrrd.$ ani1 Minili:: i n th; UK. Thcse ihiw
Secwi;iii iis ni:a di ilie B,>.irJ , t i Adrnini,lraloi3 o1 ilie EFC. TIicrc is nii
unnwd Gciiernli\sseml>ly;li which delegales fknlm al1 meiiiher soeieiies ntesl
lo detemiine ai14 a]~prnveEFC policy. News 01: E X ttctivitleu, fortlicoming
confci~enccs.coui$Cs. ew.. is ptihlislied in a Iiingc iif uccr~ditedcovrtsion
niid cenain .jriurii;lls tlirou@hiliirEumpe. More dctgilcd dcscdpIinir~r>f;i~ivi&ih~
arr pven in s Newslermr prepared hy the Scieiitiric Secreru>,.
The outpui <irihr EEC takes vaiious roriiis. Papers 011 ~>iirticulai'
wpics,
e g . rkviews iir resulls iif experimeiiriil work. niuy k:published in scientitic
and rcchnical jiiumls in oiic or tucire rountries in Eurups. Cimierencii
pn>mediiigs are orieu puhlished hy the <~r;anisniian reslmnsible br lrihe
contennce.
i
Volwies i13 the EFL senes
Volurnes iii tlie EFC sei.ies
12 ModiBcntiuns or passive filn~s
Pmp<irrdb? tire Iyil?kirr~~
PUIR' ,>l?Sil?h(~!
Si:i+tfllcl' Ufld iLl#<.h«~rix~~~.s
C?/'
25
Mir
corrosion "P peinforcement iit eonciete moniturin& preventiori 2nd
C~ii.nsiniiond P r o r ~ ~ r i r r i
13 Predittiil,- CO, cormsinn in Ihe uil 'and gas industry
P~w/.l>riirfl
bi; rlir Wrlrkirrq Purtr riri Ciinrisirrir iir Oil rijid Crrs Pnidti<:t;r,ir
26 Aclvai~m~
in corrosion contrul nnd rnaterials in oil i~ndgas
(Oi11r>f pdiir!
I 4 Guidelines fortnethods of testing<rnù r w c h in high temperature
eo~i'osinn
P i r . p a ~ 4!t? t h Mrkirzg
~
POI-T 01,Cf~~.li>riori
I>\.
Ci>rrrbrm.rri~+~r
Produc~~s
G<LSC.Y
rritd
3 Elec~rodlei~iicaJ
a p p m c h to selected mi.rosion and corr~sion
eontrol s t ~ ~ d i o s
15 Miwubial sorrf>sion
Prr,juwcI by rhe Wnrkiirg P«17(, (111 ~Wicro/>;d
C,+rrt>.liir,rt
Piipci, /rnri~50th ISE MPRF<I+&
Posii<l. IY9Y
~y ~ i c r d > i aCorposion
l
(Praceediw mf the 4th Interniitional EFC
16 GnitlPlitirs on materials rcquirciiieiits for carbon nnd low dloy
stecls for Hficontninisg environmenrs in oil riiid gas p d u c t i o n
P~?(?UPC~I
//ti r11c Itixkiny Pir1'1: ora G>rn>sioirNi Oil ct,irl Grr* Prodr~rioir
17 Corraciun msistant nlloys Fflr. oil 2nd gav piaduetinrr: suidmce oh
genera) rr<luirrn~cnts
and tess nleth<dhibr H3Sservice
P1'ep<rrc<ll?:, 1/11! W~rkiiigPc~rr?OII Crhrn>,sir>t~
i11 011
' urtd Gu,s P r o d ~ ~ : t i , . ; ~ ~
\Vorkshop)
p,el>rrrrd br thc 1*1i.krrf# Pnrly o~iMrcinbidCorri~slnii
30 r>urvey of literature on erevice uorrosiaii (lY7+19<%k meehanisms.
test mrUt<dsn»d results, pructical experiencu, yrotectjve rntrJsures
und monitoring
P i r p ~ r m ~ l F P. IJS.<PIC~I~
urrd the Winkidt* Pur- <>ti bfarllic C»l?*rro*t
i % Stainless sieel in coiicretc: state nl the art repnrt
Prenclred I')>~ize
Wor$i,r~PIO? m! C~rrw.,-ir>ri
<$HL>ir!li>ir:cniwiti
Co>!icrrrc
I 9 Seni water corrosi~>n
of stainlesi steek
- rneehanisnta: a d
experienees
32 Gnidolines fnr thr. compilafion of eorrosion cost data a d for the
caieu~atioi~
of tiic lite cycle east ofcorrosion- a working P;trtY
report
plepcirn<ilnl
hy Ihe ~?,,h~rry
P<WI:>M, C<irir,~iuii,;iOr1 < i i JCiir; Pro~linti»il
2 I Currosion-deformatiou internctions: CDI '96in tonjunetien rrith
ELJROCORR '96
12 Aspech Un ~iiicrohohiiillyiqduad eurrosion
Papers fiwnr EUROCORR 96 i11it1rlir EFC M'r~rl;trt,vPdi.1~o r i
Cfin<rsrriii
robiul
13 CO, uisroiion control in oil atid gas pt,oductio~t-design
coesiderations
Ptelx~ie<I
bi tlic kVbrkins P<i*
giii
33 Marine eorrosion of ~(riinlesssteels: tevting, ~~%(?clioB.
~perie~i~e.
pcotection and nionitnling
Edired & D. Fé+orz
btiwrlf if Worliiig Por rv 9 urr Mliriiro Cunr>hrori
3.4 Lifetime modelling of higli t e n ~ p e r d w
corrnsion proWS8eS
P i o c c a D i ~ gqf~riii EFC IVorAsI~o~i
22»01.Edrre<tbr. M. S c i i i ~ i ~ c , .I
~X,rirlnl;k~.r~
:\od J. R N i ~ l i o l l ~
3s Corirrsioii inliilrilors ior stcrl in c<lnrrete
P,TI>I,,w/ In- ,I 'f?.vh G,riiili ,>i
\Vvvi<iiir Piirl, I l uli C,l<.ri~.siol~
(V'
Ci,rir,arm~s1 Ori oirid GIZX
24 Electn>die~tiicalrehahilitatioa iiiethudu f t ~rciiiforc~d
.
coiisrete
structums: a state of thc art reporl
Picpornl hi rlrr W~>ikiit#
Puiti OII C<inosroii ofRern$nirczlCirrr<-r~ir
36 Prediction nf long tenti c o m i o n hehaviaur in nuchrr ?vaste
systems
Edtrml Bv D Fiirin u r ~ dDrgbv D. Ma~~~l~~tru161
un behlf uf Wr~rkliry
Pam, 4 ori Nwclrnr Lrrrn~rfo~fz
xiv
37 Tat melhutis for uastwing tlie suscrptihility nf prextmssing streis to
hydrogen indueed
E<li$edli? R. /secke o?,! J><*lruy'of W C 1.i'P I l I*! Oii'ivrirr,~(?t'
Re;~$?~treiiierrf
NI C(Iticmt(~
38 Co~rnsi<m
nF reinforcernent in concrete: niechanisiiis, monitaring.
inhihifors aM1 rehal>ilitaSon techniqurs
E~litetlL,? M. R~&q~arc~Ii,
B. El.rci~ei;R. Pralilcr CIILCI
.J. bfirr: OLI I)ei1u/t'6f
Wo~kiii!:Prriiy I l oii Corrt~,si,in<$"Sreeliii Coril:irrc.
39 TIie iise «e currusinn inhibitws in oil und gw produdion
Ef1;t~fIl+ J. kK P<~/iirei:N! He<l,sc.~
f ~ r J.
~ dL. Dur.t-.sr~ir
#i
Volunies in tlie EFC series
Voluniea iit tlie EFC series
Control ol'corr~sioni11euoling ivaters
Erlired ly J. D. Hwsriiu iiird E Ri>pNol
41 Metal dusting, eacurhuriSation a d iiitridntinn
Edifcd
12% Srlrfim <<odH Ginl>kks
42 Corrosiso in rckineries
M i ~ /I?
d .I. D. /+<u-s~~,I
13 Tlre eledmcl~eiiiistryand characlei.istim of enrheddahle rrference
elwtrodes fnr concrete
l'repru.edl>i. R. Afl'rd<il mi bcitu@'qfN+ii.kirigPort? I l
d<inrisio,r of
Sreel iii C r ~ ~ : ~ ~ i . < : t t
14 The u.se nf elwtrnche~uiwìscumuiig tunnelling mict~scnpy
(EC-STMI in c a m i o n anrlysk refcrence niatcrial and prucpdurnl
guideliees
Pl.ciuiw<l& H. LirrZ~rrii,ii.I?bl<iur7cu.L X-Ick UJII/ i? I W L ~ ~
IWI
LI>cli~il/'
I.
qf CVorkfrr~I'<r~,i?6 i>nS i i ~ ; j i i c,Ts:irrir.c
45 Lucal pwhe teehniques iirr eorrouiun rcsramh
Friirtil ly R. Oltre. t< Muirriice. R. Akid on<f I.! d@omt,roii h~krvlfqf
i*ir;iirig PCI-
C<:
»il P1tr:rico-clir.iiriinl blcr6riiiis o/'Lurmsirrr f i n i r r ~
46 Anriiie uidt cormsion in mtiiirriw
Prepnwi b? .l. D. Hui:vrr,rr ~ L IEI ~R c ~ p i roit
~ ~Ixit~r/fc~fIl'orki,i~
l
Poi-: I 5
riir Corrf~,~N)i~
in rhe re fin ci;^ Iriu-r<.wii.
17 Nuvel ripyruachm iu thc inlprnvement ui'liigh terril>cra<urc
corrosiirn resistance
E<1ired i+ M. Srht~rzriirrii !I' Qlr<?tlrilLer~
rjti hku~tdCW>ikirr,g
Pr'ni .q
rirr Corrfisinr nr H<?/G a w ur~dC n l i ~ h i t i l lfr<tIII~~f.r
~i~
18 Corwsion dmetallie lieritage artefacb: invertigaLion. ronoervatiori
and predietion of long terni helirviour
E<rirr<lhi P D~llniorrri.G @6i<rii~e,i?Piriardo rrtirlH. jz.I~.~irbir>ri~,i
ori
h<.k«lfoj Wc?rktrr(!P<i,ri il<AI, Nur,le<ir Crii ~o.rroir
xv
.I.') ElectEQ~hemist.ry
in light rvater reactors: referenw tleStpodes,
rnejsuremciit. eurrctsiun and tribucuriosioo issues
&d;cr1ll,? R -W RO,-C/I,D. F6niir aid 3.-P Celu en Iwlidf oi l%rk,iis
Parli 4 ori Nia.lcer Cfii~asioii
50 ~
~bchayivmr~and prutectiou
~
uf c~o y ~ ennd
' iduminium
~ al[*ys ,
in scawuter
F,l~r,~/
b1 D. F J ~ rtli
» ~brhulfqf
~
Wn~kiiigPoi 11' 4 WII N u ( ~ @CI Io~r m i o n
~
1
Introduction
The European Federation of Corrosion (EFC) Retinery Corrosim Working
Pariy 15 has discussed a wide vanety oflopics since its firslmeetingin 1996.
At one meeting a presentatron was made on mii.osion associated with amine
units and ~hissuhject received much interest from the members. As a result
of this it wm decided that it would be beiieficìal io caiiy out a survey of
corrosion on the amine units witb which the men~herswere associaied.
This wns seen as a good iopic for invesiigation fora number of reasonr
Many sites had experienced various corrosion and craeking prohlems
associated with this type oi' plant and some oF these Iiad been shared with
the g w p .
Some sites wcre in the process of changing froin one type of amine to
nnother; so it was of inteiest lo see whether any ditferences exist between
corrosion-related probiems with the different rypes oF amine.
Conosion on amino uniis 1s fairly complex since it invoives v m u s wrroslon,
erosion and cmcking mechanisms and is affectedsignificmtly hy process
panmeters and the materials of consmuctioli.
The sribjecl was also tboright to be non-pmpnetary and therefore paiticipanu
did ilot have rcsenrations abbui sharing their data Anonymity of the data
supplied was, however, preserved by pariicipants sending in their data to
the group via the EFC Scientilic Secretary.
The amine unii corrosionsurvey wvered the following amine typw:
Melhyldiethniiolamine (MDEA).
Diahanolamine (DEA).
Monoethanolam~ne(NEA).
r D i i s o p r ~ n ~ l a m i i(DIPA).
ie
.
Thc tindiiigs 01' ihc siirvcy rmphasisc ihe impow&iice01' carellil pnicesa
coniml nnd thc hcneiicial effcci or upgrading io ausieniiic si3inlcss sieel in
n number of areas.
1
Technical background
There is already a significnni amount o l infomiition in the iiterature on
coriosion in amine unils T k following is anoveruiew of the issues involved.
2.1
Process issues
2.1 .l
Pretreatment
Units often usea knwk-out pot hefore the absorberwhere liquid hydmarbon
and water are rernoved.
2.1.2
Absorber
In ihe ahsorber, the amine removes H2S, COz and niercaptans by forming
a salt. MEA, DEA, MDEA, DIPA and diglycolamine (DGA) are the
main amiiies tliat are used. Lean amine llows down the absorber in
counterflow io the Iluid tiiat is being treated, which exits al the top with
the impurities suhshntialiy removed. The amine that has ahsorbed the
impunties in then referred to as nch amiiie and exits from the botiom of the
abs&
and flows io a regenerator. Several absorhers may feed a common
regencrator.
Tliearnine will also remove stronger acids iit ihe absorkr such as formio
acid (arnungsi uilicrs) and Lhe reaciion wiih rhcsc acids is diilicult io reversr.
cuusinp n Duild-up o i heni-sijhlc amine ralls (HSAS) 111 ihe uoiinc.
2.1.3
Regenerator
Rieh amine goes to the lean-rich exchanger nnd 1he.n on ra the regenerator.
Rich amine passes on the tube side to avoid pressure chaiiges and Hashing.
In the regenerator, acid gmes are stripped by reduction in pressure and
increase i n temperatura. Heat is provided by o reboiler, the temperature of
which needs to he core[ully conimlled in wdcr lo reduce degradation af the
9
4
Technical background
Amrne unrt corrosron in reftaries
!
amine The iimiiie salt Iiherates tlie acid gas, wliicli exiis to thc overhcnd, and
lean amine, which exits Imm the hoiioin ond is Rliercd.
2.3.3
2.2
Corrosion i11 rich amiiie solunons is increased by high acid gas loading. and
ihe loacjing ofteii has to be limited lo minimise corrosion. Acid gas f'laahing
drsturhs thc FeS proeective films. Acid gasa break sut of solulion to give
nctd attuck when Lhere 1s a high velocity md high temperature and wben the
piessure is too low to suppress vapwisation.
Importaht issues
Imporlanl issues to k coiisidertPd are:
Ainine type and sirength.
Acid g a loading
Tempemiure.
HSAS.
Solids aiid iilmtion.
Wei H,S crackiiig.
Amine eracking.
Species fouiid in regeneraror ouerheade
2.3.4
Corrosion issues
2.3.1
General factors
The nmine itseltis notmrrosive. bul corrosion is prouoted hy ihe followiiig:
.
htmined acld gases.
Higher conceiiimti«n of corrosive specics.
H i ~ h e temperatums
r
Corioslon on heat transter surljccs.
Higher velocrties.
HSAS
2.3.2
Mechanisms
Wet W2Scorrosicw,
Fe + HIS = PeS + H?
FeS 1s more priwective ihan FeCO?.
Wer C02 corrosion
Fe + H,CO, = FeCO, + H?
Wer C02 corrosion can result in Iiigh corrosiori ratcs, hul a carhonnte iilm
gives some protection and is more pmte~tiveai Iiigher tempeiatures. The
C 9 content 1s oiten no1 very hieh in rctìncry sirams, except in hydrogen
reformer phni systems.
Lean amrne
It is importani to avoid tw low a leve1 of HsS i n the la11amiie. as a small
aniount ol. H2S is helpful in producing a protective sulphide film. Primary
amines aie more corrosive than secondary and tertiary amrnes
2.3.5
2.3
R~chamine
Ac~dgas attack
H2S forms protective sulphide filma on carbon steel in many a w s but there
m pmhleiiis inarens where films cm be removed. Insuch locarions, upgrading
of maierials is required, ofren to an aus~enittcstainless steel helonging to the
300 series.
2.3.6
Heat-stable amine salts
Heal-stahle amine salts (HSAS) fwm from stronger acids cban H# and C%
and they do not therniaily breakdown al regenerntion temperarures Pioblems
orise from formic. oxalic, acetie and thiosulphumus acids and from chlorides.
sulphales. thiosulphates and thiocyanates which can come i n tmm the feed
system. Oxygen is also n source of problems and this can come in from the
Feed. amine s t m g e and make-up water. Blanketing tanks with N* and
maintaining a tight system are halpful in wder ta exclude oxygen.
High temperatures are alsoaproblem and temperaturesshonldbe mlnimisd
tluough contro1 of ihe reboiler temperature.
HSAS can also beproduced from C0 and HCN.Therefore, soma operamrs
treat Xas from tluid cetalyiic cracking units (FCCUs) wirh polysulphide t0
remove HCN.
The presence of HSAS reduces acid gas removal capacity, lowers @H.
increases conduciivily and dissolves protective films; so HSAS should be
minimised as much as possible.
2.3.7
Make-up water quaiity
Make-up wnter shwld ideal?y have low total dissalved solids and low total
hardness owing lo calcium. low cblondes, sodium. potassium and dissolved
imn and should exclude oxygen.
.
6
Amine unit corrosion in refinerres
2.3.8
Erosion corrosion
Technical background
Erosion corrosion is caused by dirty amine solulions containing solid
pnrticulares: ttlierctore lean amhie is filtered l o minimise salids.
Protecr~veFeS fllms can be damaged nnd removed under condiiions of
high
velocity, turhulence or impineement.
Benefit can iheffifore. be obtained
. by desigiiing 10 rninimise impingemenl and turbulenec. e.:. hy using large
rudius hends. The velacity i n piping is usrtally kepl below 1 ni s-'. and 3M)
ser~esstainless sccel is requiffid nt pressure let-d«wn valires.
2.3.9
Proprietary chemical additions
Sonie operstors utilise proprietary cliemicnl addilions from their siie cliemicol
supplier, although many prefer noi to use these.
2.3.10 Corrosion in regenerator overheads
Corrosion in the overhsnds of the regenentor takos n diiferent form froin
that wcumng elsewhete i n ihe aminc. unit. H2S, NH?and HCN are inipartant
spectes ihai nre involved, whtch can B v e corrosion. Condiiions are m«re
aggmssive when tmaiing srieams from cd<ors. visbreakers. FCCUs and
hydropmessoi s
m H S can be pnrliculsrly aggressive. nnd close atlention needs lo be
paid to ~oncenuationnnd veiocity wiih lhis species.
HCN is detrimental as i t removessulphidescules, which tncreases cnrrosion
and promotes hydrogen pick-up and daninge:
FeS
+ 6CN- = Fe(CN)f + S2-
Spccial atiention isneededi n order to avnid excessive accun~ulalionof NH4HS
and HCN i n the regenerator overhead retlux system.
2.3.1 1 Hydrogen-related cracking in wet H2S systems
Sulphide siresr crnckiiig i$prcvcnied hy niiiiiniisiiig ihc iiitrdncss and ptrcngih
oiihe alloys used i i ~wci
r H2Ssysicnis. This i s accoinolisliul throucli maicrial
seleciion. and ihe contro1 o1 weld procedtiies aiid post-weld heni treament
(PWHT).
Hydrogen-(pressure-)induced cracking (HIC), including stress-orientated
hydrogwi-induced cracking (SOHIC). is mitigated hy Ihe use of improucdquality steel plaie and PWHTor the use ofcorrosion-reasiani alloy claddiiis.
-
2 3.1 2 Alkaline strecc c o r r o s i o n cracking
API 945 recommends PWHT n%followr.
.
MEA: PWHT far service at al1 temperatuffis.
DIPA: PWHT tor al1 temperatures.
DEA: PWHT For temperatures of M] "C (140 %) and above.
M D ~ PWHT
:
For service at temperatuffis o f 82 'C (180?l' and @hove
I t is also necessa i o take care of stoam-out conditions.
2.4
Materials
Carbon steel cali be used wiih suceess formany areas but matcnal upgrading
i$
nececsary i n highly corrosive nreos. Use hns been made ot matenals such
as the austeniLic stainless steels 304L and 316L. 2a05 duplex stainless steel
and othw high-iilloy mslerinls sttch as Alloy C or Sfeltite lòr valve fom.
Experiences of ten plants using
methyldiethanolarnine
The pia111tiiinikrs ore given rnparenthescs
3.1
Gas eomposition
Recycle gas: H2S, 1 148 kg m01 h-': C4,0.816 kg mol h-'
Cold rlch gas: H2S, 36 170 ka mol h-': COz, 2.176 kg mol ha'
(1)
H2S, COz, NH3
H2S, CO2, NH*, HCN
(2)
H*S. C02
90% H&, 6% COI
(4)
(5)
Not available (NIA)
(7). (8)
(3)
1.5%HzS, 3.3% CO?
(9)
0.1% H2S, 13-14% C02
(10)
3.2
Materials of construetion
Carbon steels
Typical: <D. 16% C. 4.0'25% S, 4 . 0 3 % P, killed CS
3.2.1
N/A
A42
<0.2% C. ~ 0 . 0 3 %S. ~0.035%P
A516 Or. 70
A516 Gr. 60
10
Amine unit conosion in refinenes
3.2.2
Special carbon steels
Experiencas of ten plants using methyldiethanolamine
11
Regsnerator hoitoms: Belzonu 1391
None
Regeiierator refiux drum. clad with 316L stainless steel
NIA
Regenetator reI'lux drum: Saknphen coating
235
Feed hottoms tube shm: clnd with Ti
0.001-0.005% S. 0.01En.O2R% P; Dillinger
Reflux drum: clad with 316L stainless st-l
One AS16-65(Z35) reflux druin
3.2.5
3.2.3
Spectal stainless steels
Stress-relieving policy
Not known
None
Systematic stress reliel'
NIA
Old, no: new. ycs at any twnperature
Regeneraior rich amine iiilei: 304 siainless steel
Yes, al1 including sour sas pipins
Top section uf the tower: 3WL stainless sieel
Regenerator rchniler tuhes: 1 8 8 Cr, 1% Mo and mhe sheei
Croniler 2205LCN
3.3
Operating parameters
3.3.1
Amine parameters and foaming
Rehoilers, shells. iubes. bnffles: 304 stainlcsl sleel
Rebailers. 1uhe.s. 1818 steel
Rehoilers, tuhes: 316L stuinloss sieel
Ahsorher intemcils: 3WL stniiiless siecl
Feed-efflueniexchnnger iukr: Ti giade 2
ucemol HS roi
35-45
47. 12 and
i n m l h-l
Feed-effluenl exchaiiger tuhes. typ<:321
12
Packing rings in regenerator. starnless steol
Pump hodies 2nd impellers: now stainless steel
Soim nch aiiiine pipewwk 304L sieinless sleel
Lean amine pipcwork: 3il4L ns~nlesssieel
3.2.4
Overlays, cladding and coating
No
NIA
Reboikr shell: 1.4571 clad with 316L siarnleis sieel
Regeneratnr bottoms: clnd with 316L siainle$$steel
OoQwal HS i16
60-45
46
35
?
45
50
50 t h-'
zoo m3h-'
200 mJh-'
40 m5h"
100 m3 h-'
12
50 140% inventoty)
$60(110%inventory)
Na information
20 (30% inventoryl
7
(5)
l51
NO
No
Serious
17)
NO
lnfomation (8)
No
(9)
Sometimes
l101
12
Expertences of ten plants usrng methyldiethanolarnine
Amine unii corrosion in refinenes
3.3.2 Acid gases. heat-stable amine salts, velocities and
reboiler temperature3
Acid s a s s (m01 mal-')
Velocitv
In rtch amine
In isan amine
1%)
(m <'l
Reboiler
bmperature
0.523 and 0.33
0.175
0.245
0.17E-0.44
0.077 and 0 . 0 n
O 01-0.02
0.01
O 0175-0.03
'0.1
0.7
0.2
OK
OK
OK
OK
120
121
148
118
11)
42)
131
14)
0.3
O 45-0.50
0.25-0 40
N/A
0.05-0 017
0.45-0.50
0.005
0.002-0 O015
0.010-0 035
NIA
4.01
0.005-0 O9
1.7
NIA
NIA
N/A
N/A
1.9-2.0
i7 ne*,
140
133
133
NIA
133
130-140
15)
identrfied
0.8-1 5
O 5-25
05-30
NIA
O 5-1 5
0.25
Make-up water
Coiidensate
Deminenlised
HSAS*
Noi
3.3.3
13
Plant
1"CI
OumoSI
*The HSAS eniries can he Iurtl>crdcscrihed ;rs follows:
*.l'&
0.7% acetates, formates, sulphams. thiosulphates
0.28: acctatcs. fc>rmntes,sulphaies. iliiosulphatcs
Noi identiticd
0.8-1.5%: ncutralise with K2C@
0.5-2.5%. rota1 45000 ppnl acetate, iormatc. glycolatc. laciate.
oxalate. pmprionate, sulphate. thiocynnate
Boiler Feed water
NIA
(6)
17)
(8)
(91
(T01
3.3.4
Solids present and filtration
Candlc tlltcr in the regcnerator aminc circlc
IO% circulated amine on the mechanical filter: 3% on the
charcoal nhsorher
10% ciiculated amine on (Iie meehanical filter
(3)
No solids; precoat filter
(5)
Solids, up to 20 mg per 100 mi-'; Vxco filters on thc slipsucam
IO prn (5-1096 cirwlation); followed hy aii activated C filrer
for hydrocarhons
(6)
Solids. up to 15 ni_e per la0 mi: Vacco filters on the slipsweam,
10 vm (5-1096 cireulauon); followed by an activated C filtcr
€orhydmcarhons
(7)
NlA
(8)
No S O I I ~ S(maximum, 0.01 mg per 100 mi-'): Vaceo filters on the
slipstream, 10 prn (10% circulation); followed hy an aetivaled
C iilter tor hydrocarbons
(9)
Full stream pariiculate: 10% slipstream iiclivated C
0.5-3.0% total 40000 ppm iicotatc, foiiiiale. glywlste. lacnte,
oxalaie. propnonate. sulphate. lhiosulpliate, thiocyanute
3.3.5 OQ leakage
N/A
NO
0.5-1.5, toial 5800 ppm acciate, lorniate, glycolate, oxalaie.
propriooate. sulphate. tfiiocynnate. thiosulpliiite
Not known
0.25% aceiaie. thiosulphate. oxalate. sulphate. Cormnte
No, and pcissivation stcp aftcr opning the vessols to the
atmosphere
2-3% 4 in blankeling Nz on the make-up tank
3.3.6
Inlet gas knock-out vessel
Not known
(6). (7). (9)
(IO)
14
Arnine unit cotrocion in refineries
Yes
H2S in sweei gas. 100 ppm maximum
No
Corrosiai ioupons. HSAS, 398 maximum, 1% target: Amine
loading, H2S, lean 0.01 mul mal-' niaximum i c h
0.40 mol mal-' maximum, suspcnded matecial. I mg per
100 ml maximum; K, 300W ppm maximum; saluble Fe,
10 ppm maximum, soiuble Mn, 2 ppm maximum; record
soluhle Ni, CT, C;I Na. Ca
NIA, oiie with a water wash rowcr iii Roiii
KO + Filter. two siages, 5 Nrn and I pm
3.3.7
Design factors
Fe, Cr, amines, HSAS, CI-, corrosivity: wall thickness
measurements on Che stnppc': efectric8l resrsrance (ER) prohe
and coupons oii the bottorn of the outlet of the oontactor;
BR probe and cuupons on the wnpour-liquid feed into the
stripper
There ;ire st>mepmhlems
Control valve close io ihe re, "eneralor
1.5 D elhows
NtA
3.4
3.4.3
Corrosion contro1
N/A
(l), (21,
No inhihitor: neutralise HSASs wiih K,C03
Comsion inhibilor in the overheads and K2C01 rur HSAS
CN scaveiiger in thc wash waier «n the FCCU
NIA
(4). (10)
(5)
(6). (7)
(8)
(9)
Monitoring
(5)
Overhesds: 1 ppm Fe;4.7% NfhHS (no <training)
PH 8 maximum; tutal salts and conductivtty; hleed of the
(61,
relliix wnter adjustd accordingly
CN-scavenger in che wash water trom rhe FCCU
3.5
3.4.2
Control parameters
NO
3.4.1 Treatments
None
(10)
(9)
(8)
Corrosion problems experienced
(1)
Desorbers reflux Iine and pumps
WaII thickness measuremenis
NIA
Fe, amine. HSAS
Regenerator rehoiler: coriosiun of tu&
Fe. H2S. HSAS
Fe, H$
Repenemior rebuiler: corrosion o f the vapuur section, naw clnd
with stainless stffil
(5)
Corrosion cuupons in tlie reboiler vapout. Iiiie, HSAS,
2% maximum
Regenerntor rehoiler: stress corrosion cracking (SCC) of 316
stainless sicel tuhes
(10)
Corrosion coupona, HSAS, 2% maximuiii. 1% rarget; aininc
Loading. H& lean 0.01 mol moi" maximum dnd rich
0.40 mol mal-' inaximum: suspended maienal, I mg per
100 ml maxunuin: K. 30000 ppm maximum, soliihle Fc,
10 ppm moximum; soluhle Mn. 2 ppm maximum: record
soluhle Ni, Cr, CI-, Na. Cii
Rich amine fecd preheaier. SCC. now stress relieved
(5)
(21, (3)
on the shell dde
Rich amine line. from lhe valve to the column corroded, mOVe
tlie valve closer to the column
(6). ( 7 )
Lean amine genenl: H2S lean loading tuo low, increase from
100 ppm to >600 ppm
(4)
16
Amine unir corrosion in refineries
High pressure (HP) ahsorher: unifolm wrrosioii ot tlie w s e l
wall from the nofnlal amine level lo the top ot packing at the
stde o£ the gas inlet nozzle far 180' ol'circumference (note ton
low amine ciiculation rales with ioo high H2S Ioading of 1ihc
amine solution).
i61
Ti t u k fallure
(6). (7)
Regenerator: c»rrnsion n( che leve1 of the rehoila vapour relulii
line, now extend Lhe stainless sieel clad into tliis zone
(71, ( 9 )
Regenerator. corrnsion n1 tlie leve1 o? the rehoiler vapour returii
Iine corrosion of the inrernal Iaddcrs
Eio)
Vapour reiurn line: cnrhan stcel. severe corrosion and eroston,
now repldced hy siainless sieel piping
(7), (9)
Noiie
(8)
Pumps: erosion of pump bodies
Fin-fan b
m exchanger: erosion of caihciri sleel tuhes. Lo bc
replaced by stainless steel
(10)
Piping: corrosim near knds: corrosion new che inlet snd uuUct
of the puinps (diameter reduciion): replace wiih stninless siecl:
vihraiion on rich amine line cnused Fra«ing-type iallure al tlie
pipe supporis
(10)
A sumniuy of selecied daia is preseohed in Seciion 3.6.
ID
-- .-5 9 0 2
-É -5 $ 4 - 3
- C 8000
m *
7
O
0
O
0
m
s
P
a>
a
g
LC 9,,%&
0 0 , -
.-+
C
C
+
.Z
4
Experiences of twenty-one plants using
diethanolamine
4.1
Gas composition
Nat known
90% H2S. 8.6% COz, 0.3% H?, 0.3% Ci, 0.4% C2, 0.4% CJ
2% H2S, 2.6% COz. 4.8%Hz
Liquefied ptroleum gas: (LPG) 35% C?, 61% Cq. 4 8 H2S
Visbmaker. 2-14 mal% H2S (average 7 mol% H2S), 1% C%.
1% CC2 FCCU, 4-5% H2S
HzS
4000 ppm HzS
26.4% H2S. 1.5%C 0 + Nz
Ex-hydrocarbon trcntinent unil and hydrodesulphunsati~n,H 8
D F gas
~ ex-FCCU, HtS + C02, Cs fual gas
Several feeds H2S + C 4
20
Amine unit corrosion in refinertes
4.2
Materials of eonstruction
4.2.1
Carbon steels
Expenences of iwenty-one plsnts using dielhanolamrne
Rich arnine inlei pipe lo lhe rcgenerator: 304 stuinless
Steel
(IL (2),(3), (4X 15). (6%(7). (8). (16)
A42
- NlA
(9). (18).(121. (21)
(21, [3), (4). f7)
(5)
Overhead regenernlor's dmin reklux pump
Regeneraror overheads tubes: SAF 2205
Lean-nch arnine heal exchniiger tuhes: shetl and piping: 304L
AlO6B
(11)
0.15% C, 1.35% Mn, 0.02% S. 0.018% P. 0.33% Si, 0.027% Ni.
0.015% Cr, 0.002%. Mo, 0.007% Cu, 0.018% Al
(13)
N/A
Absortxr A516 Cr 70: regenet~torA285C
(14)
Rcgenerntor reboiler t&
'
aiid retum lines, also iiozzlis in the
reboiler and lower part of the rower sleeved in stainless steel;
later, rehoiler shell replnced with solid stainless steel
No intormation
115)
~ 0 . 3 %C. <0.025% S and P, O 1% Si rninirniim. 0.3-1.0% Mn
(17). (18)
Plain cwhon steel. ~0.23%C. 4.45% CC,, Vtckers haidness
(load, 20 kg1). c248 HV 20
(1%
Normd carbon steel, ~0.43%C-: Vicken Iiardness (load.
20 kgfl. 4 4 5 HV 20 iypically: A42C1, A42C3. A285C.
A37C3SR. A3TCS3, A106A. A42AP. A515Gr60, A 106B.
AS 16Gr60. ~ 1 7 9
4.2.2
(21))
(9j. (IO), (21)
(11)
Feed-hottom exchanger: 3 16L
Piping: 316L in hot lean amine, reboiler
Reg@neratoroverheads condenser, 321 stainless steel
Reboilei hundlec 304 starnless steel
Vessel, internai: 304 stainlass steel
Regenerotor: new oolumn. 1990,2205 duplex
(1)~(41,(5),(6),(7).(lI).(l41, (I5L (17).(lX). (19)
215 ahsorhcrs. 235 regenerators and overhead dmins
(2)
235
(31
7.35 absorheis, gm aeparator, rcgenerator and O-H drum
(8)
N/A
(8)
Regeneraior owrhead condensei: SAF2205
Rerum line From the reboiler to the regenmator tower: 304L
stainless steel
Special carbon steels
None
21
Ahsorber deniister pad: 304 slainless steel
Paiking suppons: 410 stainless steel
Heat eicchanper tuba at the batiom of the regonerator
Preheei and rehoiler fu&:
3 16L sninless sk%l
(9).(10)
Fe 42.2: regeneraror rchoiler huili to API 5LB
L 12)
4.2.4
Overlays, cladding and coating
Z grade used where free sour gas absorhcr
(13)
None
(1). (21. (3). (4)-(51, (6), (T), (8), (14). (15), (16). (I7h (19). (20)
H1C-resirwnt regenerator overheads Lower druin
i161
Not available
No, hut new equipmeni will bc in Z qualriy
(20)
Reboiler shingle lined wiih 304 slainlas steet
(il)
No1 known
(21)
Regeneralor overhead condenser replaced with 316L staittless
steel cladding
(12)
Regcnetator lower rop 3.5 m elad witb 304 st8inle.s~steel
(13)
4.2.3
None
Special stainless steels
Nozz1e.s nre solid 304 stainless steel
(91%( W r (21)
22
Reboiler ahsorher tower hott»m clad wiih 304 stainless ylcel aiid
solid 304 stainless steel nozzles
Amine
(13)
Other absorkr unwers noi clad
Belzona una mota1 spraycd coatings ussd i n reg~neneralorfor
repairs
4.2.5
Stress-relieving policy
Systematic stress relief of
welds
23
Experiences of twenty-one plants using diethanolamine
Amine unit corrosion in refineries
(1 ). (21, (3). (4), ( 5 ) . (Wa (T), (81. (9). ( 1 0)
Oiiginal stress rclief on loaii itminc nturn i'roni regeneraror to
the last o! t11e tliree leed-eiRiieni excha~igers;fdlowtng
iracking in some other lines, replaced with stress-rcliered
IlneS
(11)
Regenentar piping stress relicved
(12)
Loss
Foaming
Plant
No
Rare
171
Concentrafion
lwt%l
Circulation
16-23
22-27
20-24
29
45-65 t h"
1 5 3 0 t h-'
64 t h-'
170 m' h-'
52 t a'
26 t a-'
14 t 8.'
60 t 8 '
Y~s
Yes
181
191
(101
J
7
7
?
Il11
25
27
20-25
20-25
25-32
20
20
26.5
16.8
30
130 kg h '
7OQ-900 kl day-'
25 m3 h-'
50-20 m3 h-'
NIA
30 t h-'
300 t h
220 t h-'
900 t h-'
1500 t h-'
120 "1'8'
40 t C'
NIA
NIA
105 t a-'
No
0.25 kg t"
10 t a'
1.5 t a'
60 5 t a-'
I n x invenfowl
Yes
1121
1131
i141
'
No
Frequent
No
Nat aftsn
No
Rate ur no
lnfrequent
1-2 per rnonth
Occ~slonal
1151
(l61
1173
i181
H91
1201
i211
Al1 vessels aress relieved
4.3.2 Acid gases, heat-stable arnine salts, velocities and
reboiler temperatures
All nmine .eNice pipework
Always stress relrevcd
Yes
Actd gases
No1 applied noi mentioncd
Some pnits are PWHT (absorber and resenerntor): al1 new
equipinent
in rich amine
(20)
Not known
4.3
Operating parameters
4.3.1
A m i n e parameters and foaming
Amine
Concantration
iW%t
Ctroutat<On
HSAS
Iwt%l
Loss
Foarning
In lean amine
cO 45 m01 mal-'
0.01 mol mol-'
142
0.45 m01 moi-'
N
o O5 m01 m o r '
0.25-0.47 m01 mol-' O 05 m01 mal-'
NlA
O 15-0 52 mai mol-' 0.03-0.1 mol mol-'
N
0 77 mal mol-'
NIA
0.0044 4 m01 mal"?
0.1-0 26 mol mol-'
0.0054 02 mol mol-'
2.0
0.0174 3 mol mol-' 0.008-0 016 m01 moC' 2.4
0.12-0.62 m01 mal-' 0.05 m01 mal-'
NIA
O 20-0.35 mol mol" 0.01-0.02 mol mol'
06
Ifarmate
Veiocrty* Rebailer Plam
(m *-'l temperature 1°C)
No
No
No
No
No
No
No
No
No
129
124
130
125
120
123
126
128
123
111
121
i31
(41
l51
161
N
i101
NIA
i111
126
i121
127
i131
171
181
191
and
Plant
Bc~~BB)
0.35 m01 moV1
0.05 mal mal-'
7
,
4 1 O00 ~ p m
e800 P D ~
0.41 m01 mai-'
0.01 m01 moi-'
1-5
Not
known
7
Not
known
Identified Not
known
<2 11.6)
No?
K,C03
known
24
Experfences of twenty-one plants using diethanolarnine
Arnine unir corrosion in reflneries
Asld gas*
k rich amine
In lean amrne
NIA
0.05-0.35 mol mal-'
HSAS
Veloctly' Reiwilsr Plant
temprature ( S I
(M%)
(ms')
1-3
(contrai
No
125
1141
bv fresh
0.05-0 36 m01 rnolL'
0.01 mol rnol-'laiml
NIA
N/A
feed)
b3
NIA
0.003 m01 mai-'
No
Not
known
lactuall
IO 9 I-' HSS
M g l-' HZS
0.116 rnd mol-'
r2H ~ S
bgr'ys
2
0.019 m01 mor'
NO
I
NO
1.13
Not
known
007
125
NIA
115)
116)
I
120
140
1171
N
1191
1
1181
l
l
I
Iderion
"
"al".,
1.51
NIA
N
1201
(13)
Low solids Ievel. excess aRer upset; 10% lem amine through
che mechmicai filtex and charcoal W: 100% lean nmine
through 10 pni eartridge iilters
(14X (15)
Solids level, 215 mg l-'
FeS p r e s e n ~no tiltrdtion
Probably high; 10 #m Cunot carrndge + Niagra
1.51
NIA
112)
Solid levels unknown; bag filters (5-10 &m); precoat filters:
C filiers
45 wtppm; IO PII>Ni8gra; no C Filter
udue.
NIA
Two candle tilters (Pall) For particulates filtering on n loop From
the amine s u r p tank
Coke dust, prccoat Itlter
Up to 4.5 Not
(neutra- known
11561
Idesisn
NIA
25
Not knowri; 10 pmNiagrn: no C filter
N/A
Not
1211
knawn
l
(design
I
valve.
4.3.5
O2 l e a k a g e
No
lS
I
'The velooity i6 le= rhan 0.91 m s-' for carbon steel and less than 2.4 m 6' h r
stainless sfeel
I
Not known
(l), (4). (5), (6). (7). (8). (9), (IO)*
( 1 3 , (141, (15). (17). (18). (19)
(2). (31, (1 1)
Two amine knks open lo the atmasphere
4.3.3
l
M a k e - u p water
Boiler feed wntei
Demineralised
(12)
O ) >(Z), (3). (h), (5). (6). (7L
Condensate (pH 8.8: conductivity, 8 &S cm-')
Noi known
No1 known, typically condensate
4.3.4
(Ws(16). (171%(18)
(13)
(IO). (lI).(i4).(15>
(19). (201, (21)
Solids present and flltration
10% circulated nmine on tha
meclranical liller; 3% on the
charcoal absnrber
I
l
N, blanket slorage
Yes, t h m g h fluid canlyiic cmckrng of dry gas and storage
4.3.6
Inlet gas knock-out vessel
No
Not known
Not large enough
(1). (2). (3L t4), 15). (6). (71, (8). (9)
Not applicable un LPCi
(20). (21)
26
Amine unit corroston in refrneries
4.3.7
Design factors
Contro1 valve as close as pu%sible
io repen
Experiences of twenty-one plants using drethanolarnine
Coupons m tehoiler; monibly monitoring of amines by
andysis, sulphides, HSAS
(11, (21, (3,(4), (5). (61, (7). (8). (9)
Yes
(l6), (171, (18)
NO
(13)
Not known
27
(IO), (11). (12).
(151, (IY). 00).(2l)
Fe conteni
None
4.4.3
Control parameters
Not known
4.4
Corrosion contro1
4.4.1
Treatments
None
None
(2). (31%(4h (5)* (6). (7). (8). (12). (17). (18). (1%. (21)
Anirfoain. 3 i a-'
(1)
Antifoam, 50 kg 8'; inliihitor. 2.6 t aii
Yes
Not known
Betz Pehomeen W5-58 in regeneraior ~verheuds:20 1 day-'
in an amme sysiem oT240T nnd K2C03slug dosed:
250-500 kg in 3-6 inonths
(IQ, (l3L (l?). (18)
Corrosioii rdies Iinked io rcgencrution iciiiperdiures, nuw
126 'C mnximum. and corrosinn rares have droppcd
Regenerator overheads, NH3 m d f,S
maximum
(12)
in reflux. 2 wt%
4,5
Cortosion problems experienced
4.5.1
Findings f o r each plant
Regenerntor iebailer ~iubeson the shell sido of tubes; cracking in
the piping for lenn amine. outlel of the regeneram p u r e of
the regeneraror overheads drum
(1)
Overhead line o l lhe regenerator between the condenser and
separator dmm
(2)
Rrch amine-lenn amine heat exchanger tubes on the nch amine side
(3)
Blistering in the regenerator overheads condenser: hlistering in tlie
regeneratar overheads separator
(41
Fe contenl; HzS luading. puQe 2 iimes per week ot iegenemtor
overlieads druin
Corrosion of lhe regeneraor overheads circuit
(5)
Fe conient; H-S loading; HSAS. hydrocarhons
Corrosion hy lean amine on the rich-lean exchanger; corrosion by
rich amine on the tube side o f che rich-lwn exehanger
(6)
Ciacking o£ welds on the regenerator lean amine oullet; corrosion
of the nch-leun exchanger on the tubes i n the nch amine; pitting
of the regenerator rehailer
(7)
Overheads corroamn inhihiior
(13)
(14). (15)
Nalco inhibitorrepluccù ti? August '98 hy 7% %)da inicction
4.4.2
(20)
Monitoring
Fe content; H2S loading
l 1). (2). (3). (4). (61, (71. (8)
Fe conients and HSAS
Not known
Rwirne non-destrructive cualuelion
ER probos in regenerator overhcads, reboiter inlel and ouileis; lenn
amtne in leon-rich exchangers; weekly samples irf Fe, Cu, Mn.
conductiviiy, pH. Na. umines, HSAS. total acid gas aud w i d gas
lopding; periodic sainpjes or Rlterahle stilids, hydrowrbon
content to measure iilter and octivaied C performance
Pilcing o f the shell
rcgeneraior trays
113)
iuhcs oi che regenerator reboiler: pitring of
(8)
Fouling of ihe rich-lean amine exchanger in U z rich amine
(9)
No1known
(10)
Experiences of twenty-one plants using diethsnolamine
29
Cormsion of che rehoiler shell; corrosion ol tlie regenerator opponite
the r e h l e r return; cracking in non-slress-relieved lines in che
leali amtne at 60 *C: c o m ~ i o non the Ican arnrne side of the
lean-rich exchangei
(11)
Corrosion in the regenerator, reboiler and preheat; cracking in Lhe
head of the preheat aiid in the ahsorber
(18)
No signilicant ~orrosionproblems: regenerator overheads air
cooler carban steel life, 8 yean (0.2 mm C')
(19)
Severe cormsioii behind the regeneralor senl pan downcumer.
hlistering of the regeaemlor overheads druin [replnced): parlilion
plate distortion oF the amine cooler; regenemtor overhead nonle
and tubo mrrnsion (upgiadeù to 304 stainlew steel): rcgeiierauir
rehoiter shell carroded; regenerator feed-hotloms exchanwr shell
und tubs connded niid changed io 3 1hL 8lalnleSs steel;
pipework corroded
Regenerator rehoiler lubes (oow neutralise ecids in tbe solvent
vapour return Iine from the reboiler and use line insulafion to
prevent condensation); neutrdisation of acids in lean and fa1
solvent line work; reduction in solvent velocity by inereasing
the line size, also reducing the tempciature and incrc~singthe
DEA strength
(20)
No conosion
(21)
28
.
Amine unit cormsion in refineries
Re~neratorreboilershell in top adlncent to tho outlet noale; shell
nozzles now weld overlaid with 309L stzinless steel and shell
coated with Belzona 1321 S metal; also i t i the hundle. corrosion
oFCS baflles oli the shell side. now replnced with staiiiles~steel
(tuhes are 304 stainless steel); anolher shell weld repaired and
meial sprayed with euteetic Castolin Proxon 21032S (45% NI,
20% Pe. 20% Mo, 5% W, 10% Ti); two regenerator towers
severely corroded on the side wall opposite the reboiler retum
inler nozzle (aitrihuied io high HSAS cuntent (57%)).one iower
coated with Belzona 1321 whicli reduced cormsroii hut stdrffid
to hieak down hul was iioi repaired as HSAS wete hrought
under iontrol. severe conosion ol'necond iower ( l 4 min dowii
io 3 miil): che vessel inetal aprayed wilh 1804 wire (75% Ni.
8% C
.I 5% Fe, 5% Mo, 7% Al); surfnce huill up with Belzona
13 11 (R metd) m d eoeted with two coal, of Belzona 132 1 S
metal, subseqlieiitly replaced with a 304 stninless steel clad
secti~in
( 12)
4.5.2
(7),(8), (Il), (12h (13). (l@. (!7), (18)
Regenerators
Regeneator overheads dmm
Regenerator overheads condenser
Regenerntor overheads piping
Regenerato?reboiler
Rich-lean exchanger
Lean amine
113)
Rcgcneruiur rchoiler c<iritii~ually
wrrtrlcd wiih p.li;ng 2nd
<vaince. reol~cedin 1990 wiih SAF2205 iuhes niid clad iubc
sheet:ieanl~ch exchanger hundle retuhcd i n 1988 and 1996.
erosion at hundle haftle-shell interfnce. shell repairs anlicipated
SODR
Location of problems per item of equipment
(14)
Continua1 tube piiting of iegenemtor rehoiler, the bundle replaced
in 1990 and 1946. shell vnnour sodce surfaces corroded io
50% af allowance: Iwn-rich exehanger Iiad minor pilling, no
seriws prohleins
415)
Blistering of che regeneration tower top dome, nlso clogging d
relief mlves and some eorros~oii.md emsian
i16)
Crackingnt che regenerator columri nnd gniiding: retuhe ot Che
rehoiler
(17)
(l), (77,
(1 1). (12). (13). (141%(W, (17)( 18). (20)
5
Experiences of four plants using
monoethanolamine
The plaial riiin~bersape grveli in parerirheses.
5.1
Gas composition
i 1.04% H2S
16.24% H2S
20.00% HIS
5.2
Materials of construction
5.2.1
Carbon steels
~ 0 . 3 %C, ~0.025%S and P, 0.1 % Si minimum,
0.3-1.0% Mn
0.13% C, 0.007% S. 0.010% P, 0.29% SI, 0.68% Mn;
0.18% C, 0.012% S, 0.019% P, 0.26% SI, 0.79% Mn
5.2.2
Special carbon steels
None
5 2,3
Special stainless steels
Preheni and reboiler tubes: 304L stainless steel
Prehent and reboiler nnd reclnimer tubes: 3ML stainless steel
Filter shells: 304 stninless steel
(1)
(2), (3)
(4)
Experiancec of four plants using monoethanolamine
32
Amioe unit corrosion in refineries
5.2.4
Overlays, cladding and coating
5.3.5
O2 leakage
No
None
5.2.5
33
5.3.6
Stress-relieving policy
Inlet gas knock-out vecsel
Yes
Yes
No policy
5.3.7
5.3
Operating parameters
5.3 1
Amine parameters and foaming
Yes
Foaming
L W
Amine
Design factors
Plm
5.4
Corrosion contro1
5.4.1
Treatrnents
None
20
20-24
50
0.075 kg t*'
40
20-24
7
70
0.042 kg t-'
0.042 kg t-'
5 I a-?
20
Rare or no
Rare or no
Rere or no
No
111
(21
5.4.2
131
141
None
Monitoring
Monitoring of corrosion rales
5.3.2 Acid gases, heat-stable amine salts, velocities and
reboiler ternperatures
Aiid g a s a
In rich amane
In Ican amlna
40 g IF'HZS
39 g T'HS
39 g r1H2S
Not olear
3 g I-'H&
S g l-'HS
5 g i'tt,S
Not clear
5.3.3
Make-up water
5.4.3
HSAS
Velacitv
Reboiler
brX?l
(il <'l
temperature
ISCl
Not knom
Not known
Nar known
No racords
2.6
4.6
3.8
No reeards
130
125
125
107
Deminenlised wnier
Condensate
5.3.4
Solids present and filtration
Coke dusi snd preconi filler
Mecbanicnl fifter o i lean MEA
Plant
I11
121
131
(41
Control pararneters
None
No! known
5.5
Corrosion problems experiencecl
Regeneratof. corrosion
(2). (3)
Regenerator overheads: thinning of walls in top air cooler
(4)
Regeneraior reboiler: cotrosion of shell
(3)
Lenn-rich cxchanger: coriosion of channels
(3)
No cotmsion
(1)
Experiences of one plant using
diisopropanolamine
6.1
Gas composition
92 vol% H*. 3 VOI%CO2, 4.5 v d % H20, 0.3 VOI%HC
6.2
Materials of construction
6.2.1
Carbon steels
ASTM A516Gr60; API SLB,
0.17% C maximum. 0.01% S maximum. 0.02% P maximum. 1.3% Mn
maxiinuni, 0.41% C,, maximum
6.2.2
Special carbon steels
Nomnlised steel + inclusion shape contro1
UT BS5996LC4 for plate
Maximum Vickers hardness, 235 HV (Brine11 hardness, 225 HB) for base
metal, heat-affected wne snd weld for environments where H damage
such as SCC, HIC or SOHIC might occur
Temperature, <l50 'C
s50 ppm HZS i n the nqueous phase and pH <5
>l000 ppm H,S and pH >5
Presence of cyanides. >20 ppm
1.e. sour gas service piping, absorbers, rich aniine solution plping, regenerntor
nnd regenerator overhend system
36
Amine unit corrosion in refineries
6.2.3
Special stacnless steels
Experiences of one plant using ditsopropanolarn~ne
6.3.5
Some equipment interna1 structures such as column tnys and AISI 410
No
6.2.4
6.3.6
Overlays, cladding and coating
6.3.7
Aecording lo inspections and laborntory iiivea1igeLions. br carimn siecl
suscei>lihle l o intmxranular
SCC i n lean DIPA eiid to H Jemage
. i n nch
DIPASusss relief tor Ican amine scrvice piping iiicluding ahsorheili aiid hgeneralors
(leen + rich)
Operating parameters
6.3.1
Amine parameters and foaming
Amine
Concentretion
€irculetion
ims h-'!
23-27
300
In iean amine
=ZO (IW
800
Corrosion contro1
6.4.1
Treatments
Monitoring
None
(t a-')
6.4.3
150OW-160000
IWWOI
Veloilty
(m C')
0.69-0.81
Normally = l
HSAS
6.5
Rebailer
temperature
('CI
122 rnaiimum
i
I
l
Make-up water
Condensate: Fe concentration. 20-50 h:: I-';conducliviiy, <O 01 mmol ti:
oil, <0.5 mg I-';pH = 9
Solids present and filtration
> l 0 kni hased on a Dahliiian self-clemiiig Rliration sysrem
Control parameters
Conductivity <l0000 mS m-'
Not normallv
l
In nch amine
6.4
6.4.2
Acid gases, heat-stable amine salts, velocity and
reboiler temperature
Acid g a s s lwtppm HrSJ
Design factors
Yes
Faaming
LOSS
1% OIPAI
6.3.4
Inlet gas knock-out vessel
None
6.3
6.3.3
O2 leakage
Yes
None
6.3.2
37
Corrosion problems experienced
A t ihe heginning o f the 1980s. leaks discovered in the piping, leading to an
eztensive inspectioii, i n which intergranular SCC was discovered i n lean
and rich amine; also HIC and hydmgen ernbrildement occurred; now
PWHT used in leaii amine service and special cerboii sreels i n sour or ricli
amiiie scrvice