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CONTENTS

1.0 Introduction

2.0 Causes Of Flare Load

3.0 Design Guidelines

3.1 Radiation

3.2 Noise

3.3 Glc Of Toxic Co!ustion "roducts

#.0 T$%es Of Flares

#.1 &le'ated Flares

#.2 Ground Flares

(.0 Flare )$ste Co%onents *nd Conce%ts

+.0 Design Of Flare )$stes

+.1 Flare Load

+.2 Flare ,eader

+.3 Flare )tac-

+.# noc- Out Dru

+.( /lo Don "u%

+.+ ater )eal Dru

+. "urge Gas Reuireent

+.4 )o-eless O%eration Of Flare

.0 In5ouse )oftare *'aila!le For Design Of Flare )$ste4.0 )a%le Calculations

6.0 Co%arati'e )tud$ Of Flare )$stes Of Different Refineries

10.0 Flare Load Reduction /ased On Interloc-s

11.0 Flare Gas Reco'er$ )$stes

11.1 Introduction

11.2 )$ste Descri%tion

11.3 Co%. )election 7 )uction Control

11.# O%erating Feed!ac-

11.( *ttac5ents

12.0 8oe9s Conce%t Of Flare Gas Reco'er$

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1.0 INTRODUCTION"riar$ function of Flare is to con'ert flaa!le: toxic or corrosi'e 'a%ours to lesso!;ectiona!le co%onents !$ co!ustion. Dis%osal of co!usti!le gases: 'a%ours andliuids !$ !urning is acco%lis5ed in flare. T5is ser'e as an eergenc$ dis%osal s$ste toeliinate excess 5$drocar!ons coing to it due to'a%our %roducts or !$ %roducts 5ic5 can not !e

ar-eted."rocess flares are used %riaril$ in t5e oil and %etroc5eical industries fro initial%roduction t5roug5 trans%ortation: storage: refining and %rocessing. Flares are also usedfor ot5er %rocess a%%lications 5ere 5$drocar!on eissions ust !e controlled. * feexa%les include< )eage digestors: coal gasification and liuefaction: roc-et enginetesting and 5ea'$ ater %lants.T5e ain o!;ecti'e of t5e flare 5as !een to disc5arge flaa!le and aste gases at a safelocation and !urn t5e in order to %rotect t5e en'ironent fro %ollution and 5a?ards.

Flaring: !eing a critical o%eration in an$ %lants its design ust !e go'erned on strictsafet$ %rinci%les.T5e 'arious %ro!les associated it5 flare are ( seconds a$ !e assued and ( > 10 seconds ould ela%sed!efore indi'idual could see- co'er or de%ort fro t5e area: 5ic5 ould result ex%osuretie 4 > 1( seconds.

&x%osure tie necessar$ to reac5 t5e "ain t5res5old.

Ra!iati$n inten%ity Time t$ pain t&re%&$l!/T8A5r>ft2 A2 )econds

((0 1.# +0#0 2.33 #0620 2.60 301(00 #.3 1+2200 +.6# 63000 6.#+ +#00 11.+ #+300 16.4 2

T5e radiation le'els ta-e into account t5e influence of clot5ing: !ut excludes t5econtri!ution of ind c5ill factor: a!ilit$ of %ersonnel to face aa$ fro t5e radiationsource and lac- of large o%en areas on offs5ore %latfors.T5e 5eat radiation figures are exclusi'e of an alloance for solar radiation. In our countr$solar radiation ould account for a!out 3(0 /tuA,r ft2 5eat and it is recoended t5atfor continuous ex%osure solar radiation s5ould !e ta-en into consideration. In t5at casealloa!le 5eat radiation !$ co!ustion s5ould !e ta-en as (00 > 3(0 1(0 /tuA,r > ft2.For ot5er conditions for calculations solar radiation s5ould not !e su!tracted.

3.2 N$i%e:T5e ex%osure 1 inutes for noise %rescri!ed in soe of t5e ell acce%ted standardsare gi'en !eloBet5$lox$et5anol 2( Bet5$l c5loride 100

Bet5$l$clo5exane (00 Bet5$lc$clo5exanol 100Bet5$lc$clo5exanone 100 Bet5$l forate 100Bet5$l a$l alco5ol 2( Bet5$lene c5loride (00

Na%5t5a @coal or tar= 200 Na%5t5a @%etroleu= (00%Nitroaniline 1 Nic-el car!on$l 0.001Nitro!en?ene 1 Nitroet5ane 100Nitrogen dioxide ( Nitroet5ane 100

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Nitrotoluene ( Octane (00O?one 0.1 "entane 1000#a% $r )ap$r **+ #a% $r )ap$r **+"ro%$l -etone 200 "5enol ("5en$l5$dra?ine ( "5osgene @car!on$l c5loride= 1"5os%5ine 0.0( "5or%5orous tric5loride 0.("ro%$l acetate 200 "ro%$l alco5ol #00"ro%$l et5er (00 "ro%$lene dic5loride ("$ridine 10 Euinone 0.1)t!ine 0.1 )t$rene 200)ulfur dioxide 10 )ulfur 5exafluoride 1000)ulfur onoc5loride 1 )ulfur %entafluoride 0.02(1:1: 2:2>Tetrac5loroet5ane ( Tetranitroet5ane 1Toluene @toluol= 200 o>Toluidine (Tric5loroet5$lene 200

#.0 T,*E OF FLARES

T5e ideal flare is a de'ice t5at !urns 5$drocar!ons co%letel$. T5e co!ustion s5ould!e so-eless: least nois$ and it5 iniu incon'enience to counit$ in tersof radiation and luinosit$ as%ects of flare./ased on s%ecific reuireents 'arious flaring conce%ts 5a'e eerged and are !eing%ractised. arious t$%es of flare are "erissi!le !ac- %ressure

T5e load is estiated for 'arious eergencies and to arri'e at design flare load: oneeergenc$ is considered at a tie in one %lant.

Flare Load for a Co%lex )egregation of "oer Distri!ution t5roug5 'arious )u!>)tations.@ Refer design

!asis of ,"CL B!ai.=> Flare load reduction !ased on INT&RLOCs. @ Refer section 10.0 =

@ ex. 5en Cooling ater failure occurs in a colun : stea su%%l$ to col. /ottore!oiler ill sto% iediatel$.=

+.2 Flare /ea!er:T5e flare 5eader ust !e si?ed so t5at t5e !uilt>u% !ac- %ressure at t5e outlet of relief'al'es does not exceed t5e axiu %erissi!le 'alue. In soe cases if alloa!le !ac-%ressure is go'erned !$ less load and for a;or flare load 5ig5er !ac- %ressure is alloa!let5en to %arallel 5eaders one L" and ot5er ," are run if it is econoical.Flare %i%ing s$ste

1= Indi'idual disc5arge lines fro ")s.2= )u!5eaders in eac5 area connecting to disc5arge lines.3= Bain flare 5eader leading to OD.#= Final 5eader connecting t5e 'a%our line to flare stac-.

)i?ing Flare ,eaders1= /ac- %ressure i.e. 10 of set %ressure in %sig for con'entional t$%e and#0 for !alance t$%e 'al'e.

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2= To a'oid noise %ro!le: 'elocit$ is liited. General %ractice @.2 > .(= Bac5nu!er is selected.

)onic 'elocit$ c 223 A TABc in ftAsec C%AC' norall$ T oR B Bol. t.5en dia of OD exceeds 12 ft: s%lit flo arrangeent is econoicalFor estiating !ac- %ressure at safet$ 'al'es t5e folloing losses are to !e added .1

Noral o%eration > .3D2 x2K ,2

x 20 te 20 ftAs 'elocit$ of esca%ete tie of esca%e to a safe location

For a 5ig5 te% s$ste: a se%arate su!5eader a$ !e reuired u%to t5e %oint: 5eret5e te% dro%s don to t5e alloa!le liit. * 5eat loss of 10 /T8A5rAft2 a$ !e ta-en ast5u!rule for 5eat loss calculations.For lo te% s$ste: flare su!5eaders a$ siilarl$ co!ined into a single lo te%flare 5eaders and %i%ed all t5e a$ to flare stac-. ,ere: a 5eat gain calculation is doneto find out: 5et5er su!5eader can !e connected to ain 5eader or not.

)IB"L& *""RO*C, FOR FL*R& )T*C )IING/asic dataBaterial floing is ,C 'a%our

Flo rate @-gA5r=B *'g olecular eig5tT Te%. Of fluid floing @= Co%ressi!ilit$ factor @Generall$ ? 1.0 is ta-en="2 "ressure at t5e ti%d Flare diaeter @= @inside= Ratio of s%ecific 5eat, ,eat of co!ustion @; %er -g=

Calulati$n $f DiameterBac5 No. 3.23 M 10>( @ A @ "2 M d2 == @ MT =A @ MB== 0.(

Flare stac- dia is generall$ si?ed on 'elocit$ !asis : alt5oug5 %ressure dro% s5ould !ec5ec-ed. elocit$ u%to 0.( Bac5 a$ !e %eritted for %ea- load and s5ort ter. 0.2Bac5 is aintained for ore noral and %ossi!l$ ore freuent conditions for lo%ressure flares: 5ic5 de%ends on folloing criteria5alf t5e flo ratedeterining one 5alf t5e 'essel lengt5. T5e noral calculations ould !e used for ite cand d ill not !e du%licated 5ere.T5e folloing forula can !e used for si?ing 5ori?ontal drus for se%aration of #00

%article< 3+0M D2 @eL> eG=M BM"A T SJ

5ere:

l!sA5r of 'a%our eL liuid densit$ l!sAcu fteG gas densit$ l!sAcuftB ol. t. Of t5e 'a%or T te%erature of t5e 'a% in oR." %sia:D dru diaeter in fit

)iilar ex%ressions are a'aila!le for 'ertical -noc- out drus. * %ractical forula for t5e'a%or 'elocit$ is eG= AeG ftAsec.

+.( 4LO5DO5N *U+** !lodon %u% is %ro'ided to transfer liuid fro .O. Dru. T5e %u% ca%acit$ is%ut eual to t5e axiu %ossi!le condensation rate during %ea- flaring. ,oe'er: t5einiu %u% ca%acit$ s5ould !e ( 3A5r. T5e %u% s5ould 5a'e %ro'ision to start andsto% autoaticall$ t5roug5 le'el sitc5es on .O.D. T5e !lodon %u%s selecteds5ould 5a'e iniu N"), reuireent and OD s5ould !e ele'ated suita!l$ to eett5e N"), reuireent. T5e condensate in t5e OD s5ould !e considered as su!cooledfor t5e N"), @a'aila!le= calculations. T$%ical N"), @a'aila!le= for t5e condensate %u%is 2.0 and t5e OD s5all !e ele'ated at .( @in= fro t5e grade. ,ig5er ele'ation of

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t5e OD results in increased ele'ation of t5e flare 5eader: t5us increasing t5e s$stecosts.

+.+ 5ater Seal Drum)eal is %ro'ided at t5e !ase of flat stac- to %re'ent an$ flas5 !ac-. In a!sence of seala continuous entr$ of gas a$ !e !led to flare.)eals are to t$%es

> Liuid seal> Gas )eal

Liuid seals are furt5er classified a )eal Dru 7 )eal %i%e. In seal dru liuid sealis located. "i%e is an integral %art of t5e stac-.T5e %ur%ose of seal dru is to aintain a seal of se'eral inc5es on inlet flare 5eader:not exceeding six inc5es ot5erise: it a$ cause !ac- %ressure on O"D. ater isnorall$ used on sealing liuid in cold cliate soe extra %ro'ision is needed eit5erater is 5eated or ater is re%laced !$ alco5ol: -ero etc.For designing ater seal dru: )5ell et5od is used. Refer attac5ed fig.

+. *UR#E #AS RE6UIRE+ENTIt is essential to %re'ent air ingress into t5e flare s$ste. T5e ost acce%ta!le safet$easure is to ensure a %ositi'e flo t5ru flare s$ste. It is noral %ractice in industries tosu%%l$ gases to t5e flare s$ste constantl$ to a'oid a static condition of flo. T5ese gasesare referred to as %urge gases.T5e uoted 'alues of t5e iniu reuired %urge gas 'elocit$ 'ar$ fro as lo as

0.0+ to 3 ftAsec. ,oe'er: t5ere is general agreeent t5at a coerciall$a'aila!le gas seal installed iediatel$ !elo t5e flare at t5e to% of t5e stac- esta!lis5es%erfect safet$ to t5e flare s$ste 5en t5e %urge 'olue aditted is ca%a!le ofaintaining stac- 'elocit$ fro 0.0( to 0.10 ftAsec. To !e safer side it is recoended touse %urge gas to 5a'e 0.1 ftAsec: stac- 'elocit$.

*ur1e 1a% requirement in t&e flare &ea!er:

it5 seal 0.1 ftAsecit5out seal 1 ftAsec

+.4 S+O3ELESS O*ERATION OF FLARE/ecause of increasing stringent air %ollution las: so-eless flare o%eration is %rocess%lants 5as !een %referred in t5e interest of good %u!lic relations. In t5e flaring of gaseous5$drocar!ons: t5e tendenc$ for so-e %roduction as t5e gases !urn is go'erned !$ t5eeig5t ratio of 5$drogen to car!on in t5e gases !ut is not directl$ %ro%ortional to t5e ,ACratio !$ eig5t.T5ere 5a'e !een nuerous a%%roac5es to t5e %ro!le of so-eless !urning of aste%rocess gases. )ince t5e %rinci%le eans for su%%ression of so-e in'ol'es t5e 'ariousc5eistries associated it5 reaction of ater 'a%ours it5 t5e co%onents of t5e flaredgas strea: t5ere 5a'e !een 'arious sc5ees for deli'er$ of t5e ater to t5e !urning ?oneas eit5er stea or as ater s%ra$ in one for or anot5er.T5ere 5as !een certain liited success it5 ater in;ection for so-e su%%ression due tot5e great nuisance of a s%ra$ of un'a%ori?ed ater to grade in noral o%eration of t5eflare. Due to t5is reason stea is alost uni'ersall$ used for su%%ression of so-e in flareo%eration. 8se of stea increases t5e !urning rate !$ t5e creation of tur!ulence in t5e

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reaction gases and t5e ins%iration of air: t5ere!$ reducing t5e foration of soot. )ootforation is also reduced !$ t5e ater gas reaction C ,2O CO K ,2: %rooted !$t5e addition of stea.T5e aount of stea for so-eless o%eration can !e co%uted fro< stea ,C @0.+4 > 10.4AB=5ere stea )tea rate l!sA5r ,C ,$droca!ron rate: l!A5r B Bolecular eig5t of 5$drocar!onIt is norall$ not %ossi!le to attain so-eless o%eration of flare at %ea- flaring loads: ast5e stea rates ould !e %ro5i!iti'el$ 5ig5. T5e noral %ractice is to design t5e flares$ste for so-eless o%eration for an$ of t5e folloing reasons.1. Noral flaring loads2. )tart>u% or s5utdon of a %rocess %lant: or3. For an$ ot5er situation 5ic5 in'ol'es %rolonged flaring.Flares for su%%ression of so-e are coerciall$ a'aila!le of %ro%rietar$ designs.: T5eanufacturer s5ould !e consulted on t5e iniu necessar$ stea rate. T5e ste forso-eless consu%tion can !e %ut t5roug5 a anual reote control 'al'e or t5roug5 an

autoatic so-e detector: located at t5e ground le'el: sending signal to t5e stea control'al'e.Total flare load is su of go'erning loads fro different units !ased on go'erning factor

of res%ecti'e units..0 IN/OUSE SOFT5ARE A)AILA4LE FOR FLARE S,STE+ SI7IN#

Folloing %rograes are a'aila!le in LOT8)>123 in dir D

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6.0 CO+*ARATI)E STUD, OF FLARE S,STE+S OF DIFFERENT REFINERIES

,"CL @B=

"oer su!stationB))>( failure is t5e go'erningcase for Flare s$ste design.

Go'erning load ##6 T",

Baxiu alloa!le !ac-%ressure at unit /AL 0.+1-gAc2g

Bax. *lloa!le !ac- %ress at") outlet 0.1 -gAc2g

Flare 5eader #4 @after )D(#=)tac- 5eig5t 100

)o-eless flaring ca%acit$ 2 TonsA5r

IOCL @"ani%at=

Cooling ater failure is t5ego'erning case for flare5eader si?ing. Onl$ singlelargest local %oer failure isconsidered for c5ec-ing t5eflare 5eader si?ing.Go'erning load #( T",

Bax alloa!le !ac- %ressure 1.( -gAc2g at unit /AL

Bax alloa!le !ac- %ressure 1. -gAc2g at ") outlet

Flare ,eader (#

)tac- 5eig5t 100

Lengt5 of Flare 5eader 3)o-eless flaring ca%acit$II (0:000 133 1.A100 4.#A2.4 23A(.+ #3 Ref. attac5ed

D/ fordetails

BR"L>I 24#33 (0>100 1.3A100

4A#.( 12.(A#.( 1(.+

,"CL@B= ##6100 112 1.3A100 .2A#.4 10.4A3.+ +3.2 >do>

/"CL@B=

IOCL>"ani%at

#(323 40 1 3A100 N*A#.( 13.(A#.( 3# >do>

CRL@D,D)=

#3300 (0 0.+1A100 .2A2.# .4A3.+ #.0

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DESI#N 4ASIS

+R*L 8 II

FLARE S,STE+

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10. FLARE S,STE+

10.1 INTRODUCTION

Flare s$ste s5all !e installed to !urn t5e flaa!le: toxic or corrosi'e 'a%ors safel$5ic5 is disc5arged during startu%: s5utdon: noral o%eration and eergenc$ cases.Dedicated flare s$ste for "5ase>2 is %ro'ided.

10.2 DESI#N CONSIDERATION

10.2.1 )$ste Configuration

To flare collecting s$stes are %ro'ided. One is ain @L"= flare 5eader and t5e ot5er issour flare 5eader. ,$drocar!on and sour flares released fro t5e folloing units aredisc5arged to t5e ain @L"= flare 5eader.

> CD8AD8AN)8

> is!rea-er unit> Berox units> ,$drocrac-er unit> ,$drogen unit> GO>,D) unit> CCRAN,T unit @future=

@Note=< ," flare fro ,$drocrac-er unit 5ic5 is disc5arged inde%endentl$ in%5ase I s5all !e integrated it5 ain @L"= flare 5eader in %5ase 2.

)our flares released fro t5e folloing units are disc5arged to t5e sour flare 5eader.

> *ine treating unit> )our ater stri%%ing unit> )ulfur reco'er$ unit

T5ese to flare 5eaders are connected at ain flare -noc-out dru 5ic5 is located neart5e flare stac-.

10.2.2 Design Flare Load

For flare s$ste design: folloing cases are studied. Flare load for t5e 'arious cases issuari?ed in t5e attac5ed s5eet.

> Cooling ater failure

> General electric failure

> Fire case> /loc-ed outlet

> Reflux failure

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> &ergenc$ De%ressure

For t5e ain flare 5eader si?ing and flare stac- design: general electric %oer failure caseis considered.

Indi'idual flare outlet fro eac5 units are si?ed as listed !elo.

CD8AD8 > *s %er &IL "ac-age. @General electric failure=

/8 > *s %er "5ase>I @Reflux failure=

CCR K N,DT > General electric failure

GOK,D) > Fire case K &ergenc$ de%ressure

B&ROV > Fire case

,C8 > *s %er "5ase>I @Fire case K &ergenc$ de%ressure=

*T8 > Fire case

)) > General electric failure

)R8 > *s %er %5ase>1 @Fire case=

,$drogen > *s %er %5ase>1 @")* tri% case=

"ressure %rofile and 'elocit$ for t5e flare 5eader design s5all !e as follos.

> 0.3 -gAc2g at ain flare O Dru located near flare stac-.> 1.0 -gAc2g at eac5 unit /L> 1.2 -gAc2g at eac5 ) !ac- %ressure

> elocit$ is less t5an Bac5 No. 0.#.

"ressure %rofile for t5e ain @L"= flare 5eader at general %oer failure case and for t5esour flare 5eader at *T8 fire case is s5on in t5e attac5ed s5eets.

10.2.3 noc- Out Dru

Fi'e @(= Nos. Of Flare noc- out drus are %ro'ided in %5ase>2 as %er folloinggrou%ings *T8> ))> )R8

(= Bain -noc- out dru is recei'ing flare gas fro all of a!o'e -noc- out drus.

Flare -noc- out drus are si?ed as %er *"I R" (21. Design load for eac5 O dru is

suari?ed as !elo )our flare 5eader < )tress relie'ed -illed car!on steel it5 + C*> Bain @L"= flare 5eader < )tress relie'ed car!on steel it5 3 C*> *ll t5e -noc-out dru < )tress relie'ed -illed car!on steel it5 + C*> ater seal dru < )tress relie'ed -illed car!on steel it5 + C* ande%ox$ ceent coating> Flare stac- < )tress relie'ed car!on steel it5 3 C*

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FLARE LOAD SU++AR, 9*/ASE8II REFINER,

8nit Nae Coolingater"u%s

General&lectricFailure

Rate B

Te%

Rate B

Te%

Rate B Te%

Rate B

Te%

Rate B

Te%

Rate B

Te%

gA5 oC -gA5 oC -gA5 oC -gA5 oC -gA5 oC -gA5 oC

CrudeDistillation8nit @W#1000=

20:240

(0.+

41 243:+30

+6.3

122 2#4:002

2 126 23:000

+4 20

acuu Dist.8nit@W#11000=

is!rea-er8nit @W#1200=

10:+03

2:#

11 1:+40 14 1(+ 12:#3(

132 212 16:21#

+1 24#

is!rea-er8nit @W(1200=

10:+03

2.#

11 1:+40 14 1(+ 12:#3(

132 212 16:21#

+1 24#

)ulfurReco'er$ 8nit

@W#1#00=

12:000

> 1#(A133

)ulfurReco'er$ 8nit@W(1#00=

12:000

> 1#(A133

L"G Berox@W#1(00=

23:46#

(0 66

eroseneAetBerox@W#1+00=

1#0:024

1+2 3##

,$drocrac-er@Rx )ect=@W#2000=

1:#04

( 136 +0:010

20( #2 4:31+

2.1 1#+ #4:10

# 1#6

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,$drocrac-er@Frac.)ec=@W#2100=

1:#0#

#6 1 222:1

3 10+ 4:4(#

1#2 31 3304

(.

114 #(#1( .6

102

"ol$ *ro*dsor =W#2200=

#:3#

140 #2

*ineTreating@W#2200=

16:#(0

14 1(0 4+:+00

(0 123 #2:#00

32 11

)our ater)tri%%er@W#2+00=

2:41

14 1( 2:102 14 1#0

,$drogen %lant

@W#2300= 4:000

3.3

#4:100

2+.2

Gas Oil ,D)

@W#((00= 1#:6#6

#(.(

1(0 1:+0

2(.1

116 32:(64

13.+ 160 #0:000

#.+ +0

Na%5t5a Berox

@W#(00= 20:000

Na%5t5a,$dro>treater@W#100=

(6:#++

100

22 (2:043

6.( 23+

CCR "latforer@W#2#00= 2(:6

232+.1

1 106:2(1

30.+

1( 36:3#

#2.4 16

&xternal Fire Total

63:2#6 -gA5

General "oerfailure

#1.2# -gA5rB

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#3.0 Te%.133 oC

C failure total 31#:212Local %oer failure of ,C244.3#6 -gA5

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DESI#N 4ASIS

FOR

IOCL 8 *ANI*AT

FLARE S,STE+

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FL*R& ))T&B

6.1 INTROD8CTION

T5e flare s$ste ill !e %ro'ided for safe dis%osal of co!usti!le: toxic gases 5ic5 arerelie'ed fro %rocess %lants and offsites during start>u%: s5utdon: noral o%eration or incase of an eergenc$ suc5 ason to t5e flare load in t5e contingencies considereda!o'e. T5e flare load for t5ese units ill !e furnis5ed 5en data fro t5e res%ecti'elicensors are a'aila!le.

Coolingater)$ste

Local"oerFailure

Fire Case

Load-gA5r

Bolt.

Te%oC

Load-gA5r

Bol t. Te%oC

Load-gA5r

Bolt.

Te%oC

,old ,old ,old

6.3.6 )8L",8R /LOC

T5e flare loads gi'en !elo for t5is !loc- for different contingencies are as %er t5eestiates a'aila!le for t5is !loc- @consisting of *R8: )) unit and sul%5ur unit=. T5eflare gases fro t5e !loc- s5all !e routed to t5e sour flare. T5e estiated flare loads areas follos1: B))># 7 B))>( failureare as follos1 F*IL8R&

B))>1 su%%lies %oer to FR *"): FR "): T>01 @"G L"G= units 7 3 %u%s of FRcooling toer. T5erefore: B))>1 failure ill result t5e %oer failure in t5e a!o'e saidunits 7 t5ree FR cooling ater %u% tri%. )ince t5ere is onl$ one coon C& su%%l$5eader fro FR cooling toer: due to tri% of t5ree C %u%s t5e %ressure in t5e 5eaderill !e so lo t5at t5e ot5er %u%s ill also tri% leading to FR cooling ater s$stefailure.

8NIT) LO*D: @T",= B Te%.@oC= Rear-s

FR& CT

Notaffected

FR& *")>

> >Not

affectedFR& ")

>> >

Notaffected

,B8>> >

Notaffected

T>01 @/, L"G=>> >

Notaffected

FR CT

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FR C) ill tri%FR *")

>> >

/ot5C 7 unit %oerfailureFR ")

>

>>

>do>

FCC8136#3. 63

Cfailure

"RO"*N& 8NIT (.(3( (0

11.+ (0 (0T>401 @D&&T,=

1(.232.2 .

Leanoil failure

T>402 @D&/8T=4((0.( +4.1

Cfailure

B&* R&G&N. #.( 22.(12(T>01 @"G L"G=

(1.(0 1(0

/ot5C 7 8nit %oerfailureM.

Total @for ,C flare= 30.4

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+SS8< FAILURE

B))># su%%lies %oer to FR *"): FR "): ,B8: T>101 @/, L"G=. "ro%ane units:one %u% in FR cooling toer. T5erefore: B))>1 failure ill result t5e %oer failure int5e a!o'e said units 7 all %u%s in FR cooling toer. T5erefore B))># failure illresult in %oer failure in t5e a!o'e said units 7 FR& cooling ater s$ste failure. )inceonl$ one %u% in FR cooling ater s$ste ill tri% it ill not affect t5e FR cooling aters$ste.

8NIT) LO*D: @T",= B Te%.@oC= Rear-s

FR& CT

FR&C) ill tri%

FR& *")>> >

/ot5C 7 8nit %oerfailure

FR& ")>> >

>do>,B8

1000 100

>do>T>01 @/, L"G=

2.30 1(0

>do>FR CT

Notaffected

FR *")>> >

Notaffected

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FR ")>> >

Notaffected

FCC8>> >

Notaffected

"RO"*N& 8NIT >> >T>401 @D&&T,=

>> >

Notaffected

T>402 @D&/8T=>> >

Notaffected

B&* R&G&N. >>

>Not affected

T>01 @"G L"G=>

> >Not

affected

Total @for ,C flare= 12.3

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B))>( F*IL8R&

B))>( su%%lies %oer to FCC8: T>401 @Deet5aniser=: T>402 @De!utaniser=: B&* Regenerator 7To %u%s of FR cooling ater s$ste. T5erefore: B))>( failure ill result t5e %oer failure int5e a!o'e said units 7 to FR cooling ater %u% tri%. )ince t5ere is onl$ one coon Csu%%l$ 5eader fro FR cooling toer: due to tri% of to C %u%s t5e %ressure in t5e 5eaderill !e so lo t5at t5e ot5er %u%s ill also tri% leading to FR cooling ater s$ste failure.

8NIT) LO*D: @T",= B Te%.@oC= Rear-s

FR& CT

Not

affected

FR& *")>> >

Notaffected

FR& ")>> >

Not

affected,B8

>> >

Notaffected

T>01 @/, L"G=>> >

Notaffected

FR CT

FRC) ill tri%

FR *")22

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0 1(0C

failureFR ")

.420.3 1(0

Cfailure

FCC8>> >

/ot5C 7 8nit %oerfailure

"RO"*N& 8NIT (.(3( (0

11.+ (0 (0

T>401 @D&&T,=1(.232.2 .

Leanoil failure

T>402 @D&/8T=4((0.( +4.1

/ot5C 7 8nit %oerfailureM

B&* R&G&N. #.(22.(

12.(

T>01 @"G L"G=(20 1(0

Cfailure

Total @for ,C flare= ##6.1

M)ince stea ill !e on in t5e re!oiler: o'er %ressurisation ill !e t5ere. T5erefore loads5ould !e considered.

It is e'ident fro t5e a!o'e load distri!utions t5at B))>( failure is t5e go'erning case forflare design.

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4.# "RO"O)&D ))T&B

4.#.1 ,$drocar!on 7 sour flare 5eaders ill !e segregated. )our flare 5eader ill !e steatraced.

4.#.2 )e%arate ,AC flare ODs ill !e %ro'ided for FR& 8nit @44>D>01= Co!ination 8nit@44>D>02=: L&8 @44>D>03=: D,D) 8nit @/$ licensor= and ,$drogen 8nit @/$ licensor=.

4.#.3 * ain ,AC flare OD @44>D>0= ill !e %ro'ided at flare stac- area.

4.#.# * coon sour flare OD @44>D>04= ill !e %ro'ided at t5e flare stac- area.

4.#.( * 'ertical ater seal dru @44>D>06= for ,AC flare ill !e %ro'ided.

4.#.+ No ater seal dru is %ro'ided for sour flare to a'oid corrosion %ro!le caused !$ oist,2)AN,3.

4.#. Flare stac- ill !e ounted on ater seal dru.

4.#.4 ,$drocar!on flare stac- ill 5a'e a olecular seal and sour flare riser ill 5a'e a fluidicseal.

4.#.6 * 3+ ,AC flare 5eader is ta-en fro FR& 8nit. T5is is ;oined !$ a 30 ,AC flare 5eaderfro L&8. * #2 ,AC flare 5eader is ta-en fro co!ination unit 5ic5 ex%ands to #4;ust !efore t5e ;oining of 3+ ,AC flare 5eader fro FR& 8nit to it. * 2# ,AC flare5eader fro D,D) /loc- is ;oined to t5e #4 ain 5eader running u%to ain flare OD.It exits t5e OD as (# 5eader !efore it enters t5e ater seal dru.

* 10 sour flare 5eader ill !e %ro'ided fro L&8: 5ic5 ill !e connected to t5e 10sour flare 5eader fro D,D) unit. T5e flare 5eader runs u%to sour flare OD. *fterOD t5e line runs u%to t5e to% of t5e flare stac- t5roug5 fluidic seal.

Refer flare s$ste "7IDs for detail.

U**C 8 AURAI,A CASE STUD,

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Bain Flare )$steT5e flare load for 'arious units is enclosed as *nnexure>1. T5e flare load for t5e

controlling case i.e. cooling ater 7 %oer failure is TA5r. *n atte%t 5as !een ade toreduce t5e load.

T5e detailed anal$sis for t5e controlling case 5as !een done it5 res%ect toinstruentation %ro'ided and rationali?ation of flare loads in e'ent of siultaneous releasefro se'eral coluns in a unit. T5e details are as under: D,D): ,2 8nit: )ul%5ur !loc- : BT/& unit and

/utene> 1. )e'eral alternati'es ere studied. T5e least cost o%tion 5as eerged !$considering t5e folloing !asis )tagger GR cooling ater s$ste it5 dedicated su!stations so t5at cooling ater failure

of *8>: D,D): ,2 8nit and sul%5ur !loc- can !e considered se%arate fro existing *8>I: *8>II: CR8: "DF and Food Grade ,exane unit.

> 8se G," flare s$ste for GR atos%5eric 'ents etc !$ folloing t5e %5iloso%5$ of singlecooling ater failure at a tie.

> "ro'ision of G," to GR side flexi!ilit$ to ta-e G," flare s$ste under aintenance.

> 8se of s5ell %5iloso%5$ !$ considering tri%%ing of source of 5eat 5ene'er %ressure ofcooling ater su%%l$ 5eader is 'er$ lo.

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11.0 FLARE #AS RECO)ER, S,STE+

11.1 INTROD8CTION&xcess 5$drocar!ons !eing asted to flare s$ste can !e reco'ered !$ using a si%le !uteffecti'e flare gas reco'er$ s$ste.

11.2 ))T&B D&)CRI"TIONFlare gas reco'er$ s$ste in its ost !asic for is si%l$ a co%ressor to co%ress t5eflared gases for its su!seuent use at fuel gas in t5e refiner$A%etroc5eical co%lex. T5eo!;ecti'e of t5e s$ste is to reco'er excess 5$drocar!ons !eing flared and alsoreductionAcontainent of radiation: lig5t and glare: so-e and noise in t5e ad;oining areas.T5e critical as%ect of t5e s$ste is selection of a%%ro%riate ca%acit$ for co%ressor and toset its o%erating s%ecifications so t5at it can safel$ and efficientl$ 5andle as ide a range of%ossi!le co%ositions and rates as %ractical. *%art fro t5is: designed s$ste s5ouldaintain t5e integrit$ of existing flare linesAflare stac- s$ste. To ac5ie'e t5is: flares$ste ust !e left as it 5ad !een. No 'al'es autoatic or anual s5ould !e %lace din t5eflare lines to di'ert gas fro flare stac- to co%ressor. )uc5 ec5anical de'ices can failto o%erate 5en reuired during eergenc$. &x%erience s5os t5at t5e$ ill fail

e'entuall$ t5en e ill 5a'e no o%era!le eergenc$ s$ste. Reco'er$ s$ste s5ould !econtrolled so t5at it does not loer flare s$ste %ressure to t5at le'el at 5ic5 air couldingress into t5e s$ste. For t5is: suction %ressure of t5e co%ressor is aintained it5co%ressor ca%acit$ control !ac-ed u% !$ disc5arge rec$cle control.

11.3 D&)CRI"TION OF R&CO&R ))T&BT$%ical reco'er$ s$ste is s5on in figure>1. "art of flared gases fro ain flare 5eaderdonstrea of stac- area flare gas -noc- out dru are di'erted to co%ressor t5roug5 aco%ressor suction -noc- out dru to %re'ent an$ liuid 5ic5 a$ condense in t5einta-e line or entrained liuid fro !eing %ulled into t5e co%ressor. T5e -noc- out druis %ro'ided it5 ist eliinator to allo onl$ liuid free gases to co%ressor suction. Fornoise su%%ression: silencers are installed at !ot5 t5e suction and disc5arge ends of t5e

co%ressor. *s t5e gases get 5eated u% in t5e co%ressor: t5ese are cooled in t5eco%ressor after cooler !efore !eing led to t5e fuel gas 5eader. T5e liuid condensate ifan$ is reo'ed in t5e -noc- out 'essel.Design of suction and disc5arge -noc- out dru and also of after cooler are si%le andill not %ose an$ %ro!le due to fluctuation in flared gas co%osition and te%erature.Critical area of t5e flare reco'er$ s$ste is t5e selection of co%ressor and t5e sc5ee toaintain suction %ressure.

12.0 Um$e>% $nept f$r Flare #a% Re$-ery

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T5e ne conce%t of flare gas reco'er$ eliinates t5e need of continuous flaring of gas.T5e total 5$drocar!on gas is reco'ered fro t5e flare s$ste and routed to t5e fuel gas 5eader

after co%ression.T5e flare line is closed during reco'er$ of t5e flare gas !$ eans of a onAoff 'al'e installeddonstrea of t5e flare -noc- out dru. For safet$ reasons a !ursting disc is installed in%arallel it5 t5e isolation 'al'e. T5e co%ression facilit$ is designed to 5andle noral gaslea-age rates: it5 a s%are ca%acit$ to anage saller releases for !lodon

'al'esA")s. During large releases t5e 'al'e in t5e flare line ill o%en @t$%icall$: t5e o%eningtie for t5e 'al'e is less t5an 2 secs= and t5e reco'ering eui%ent ill !e isolated. In case of

alfunctioning of t5e 'al'e in flare line: t5e ru%ture disc ill o%en and t5e gas ill !eflared. T5e flare gas ignition s$ste ill ignite t5e flare gas. T5e flare gas ignition s$steconsists of a co%ressed nitrogen dri'en launc5er contained in a stainless steel ca!inet att5e dec- le'el. In addition a target %late is located !elo t5e flare ti%s to ignite t5e s%eciall$designed ignition %ellet !eing autoaticall$ launc5ed fro t5e launc5ing unit. )tandardlaunc5ing range 12(: Launc5ing ediu N2: Launc5ing %ressure 1(0 > 220 !ar: Bu??le'elocit$ #30 Asec @free= A 320 Asec @guided=: ignition %ellet dia 20 At > #3 gra=. 5en5itting t5e target %late: t5e %ellet ill ex%lode and generate a s5oer of s%ar-s: eac5 igniting

along its entire %at5. T5e s$ste launc5es to %ellets: t5e first 1( seconds and t5e second30 seconds after t5e o%ening of t5e 'al'e in t5e flare line. &x%erience s5os t5e gas is ignited!$ 6 out of 10 %ellets.

)$ste Failure )cenarioT5e folloing to ain safet$ scenarios need to !e considered