Procedures for pigging operation operations s
Pigging operation refers operation refers to maintenance practice for pipelines using ‘ pipeline pigs’, pigs’, for cleaning or inspection of pipeline without stopping operation of the pipeline Pipeline pigs are pigs are capsule shaped objects which travel through the pipeline, cleaning the inner walls of the pipeline by brushing action. Pigs get their name from the squealing sound they make while traveling through a pipeline. Pigging usually means inspection and cleaning of the pipeline. The pig is inserted into a pig launcher, which is essentially a vessel used to for launching the pig into a pipeline using by creating a pressure differential.
a!ards and risks involved in pigging operation The following ha!ards and risks have are typically linked to pigging operations" • • • •
#$posure to high pressure hydrocarbon gas or condensate. Physical e$ertion required to operate manual process valves or handling pig. Potential loss of containment of hydrocarbons through leaking flanges or opened valves. %isk of igniting released hydrocarbon gas or condensate
Precautions to be taken during pigging operations
&ear standard Personal Protective #quipment 'PP#(. )ll personnel should minimi!e their e$posure to the open launcher barrel. *ever assume that a launcher barrel is depressuri!ed, as pressure can accumulate over time. *ever attempt to open the barrel unless it is certain that it is at atmospheric pressure. )lways check that the launcher barrel is completely depressuri!ed before draining to the drain+vent .-. vessel. se a trolley to assist on the insertion or removal of the pig where possible. /ollow manual handling requirement to avoid injuries.
Preparation for pigging The preparation steps are based on the equipment being already shutdown and depressuri!ed"
For pig launcher 0ee /igure 1 for references to numbered valves, pressure gauges and pig signals.
2omplete the following before attempting to launch a pig" 1.
2hec 2h eck k tha thatt the the ma manu nual al la laun unch cher er va valv lves es 34 an and d 35 35 are are cl clos osed ed..
6.
2hec 2h eck k that that ven ventt valv valve e 37 and and glob globe e valv valve e 38, 38, betw betwee een n the the launc launche herr valv valves es 34 34 and and 35, 35, is closed.
9.
2hec 2h eck k that that gl globe obe va valv lve e 31 an and d vent vent val valve ves s 36 an and d 3: on the the lau launc nche herr are are clos closed ed..
;.
2hec 2h eck k tha thatt inte integr gral al do doubl uble e blo block ck va valv lves es 39 an and d glob globe e val valve ve 3; 3; are are cl clos osed ed..
:.
2hec 2h eck k tha thatt dra drain in va valv lves es 31 316, 6, 31 319 9 and and 31 31; ; on on the the la laun unch cher er ar are e clo close sed. d.
8.
2heck 2he ck that that the ele electr ctro1 =>1 and and =>6 =>6 are are inst install alled ed and wor workin king g corre correctl ctly y with serviceable batteries.
7.
%eques %eq uestt the the pers personn onnel el at at the the rece receivi iving ng end end of the pip pipeli eline ne to to confi confirm rm tha thatt the the pig sig signal nals s are are installed and working correctly with serviceable batteries.
4.
>nfo >n form rm the the per perso sonn nnel el at at the the othe otherr end end of the the pip pipel elin ine e that that a pig pig is is abou aboutt to be be laun launch ched ed..
For pig receiver 0ee /igure 6 for references to numbered valves, pressure gauges and pig signals. 2omplete the following to prepare for receiving a pig"
1.
2hec 2h eck k tha thatt dra drain in val valve ves s 31; 31;,, 31: 31:,, 318 318 and and 31 317 7 on th the e rec recei eive verr are are clos closed ed..
6.
2hec 2h eck k tha thatt ven ventt val valve ves s 31, 31, 36 36,, 39, 39, 3; an and d 3: 3: on on the the re rece ceiv iver er ar are e clo close sed. d.
9.
2heck 2he ck that that dra drain in valv valves es 35 and and 31? 31? betw between een the rec receiv eiver er val valves ves 31 311 1 and 316 are clo closed sed..
;.
2hec 2h eck k tha thatt glob globe e val valve ve 38 an and d dou double ble bl bloc ock k val valve ves s 37 37 and and 34 ar are e clo close sed. d.
:.
2he 2h eck tha hatt val valve ve 31 319 9 on on the the by bypa pass ss li line ne is ope pene ned d.
8.
2hec 2h eck k tha thatt the the re rece ceiv iver er va valv lves es 31 311 1 an and d 316 316 ar are e clo close sed. d.
2heck that the electro1 and =>6 are installed and working correctly with serviceable batteries.
Typical procedure for pigging Prior to launching a pig from launcher, complete complete the following valve line
-pen -p en the the glo globe be val valve ve 38 38 and and doub double le blo block ck val valve ves s 37 and and 34 34 in the the rec recei eive verr @kic @kicke kerr lineA lineA..
6.
-pen the re receiver va valves 31 311 and 31 316.
9.
2lose th the va valve 31 319 on on th the by bypass liline ne..
Steps to be followed at pig launcher end 2omplete the following steps to load and launch a pig from pig launcher. %efer to /igure 1 for all references to numbered valves, pressure gauges and pig signals. 1.
-pen the glo globe be valv valve e 31 31 and and vent vent val valves ves 36 and 3: on the the laun launche cher. r. 2he 2heck ck tha thatt pres pressur sure e gauges PB1 and PB6 on the launcher barrel are indicating !ero pressure.
6.
-pen -p en the the ven ventt valv valve e 37 and and glo globe be val valve ve 38, 38, bet betwe ween en the the lau launc nche herr valv valves es 34 34 and and 35. 35. 2hec 2heck k that pressure gauge PB9 between the la uncher valves is also indicating !ero pressure.
9.
2onfir 2on firm m that that the lau launch ncher er is ful fully ly dep depres ressur suri!e i!ed d by ope openin ning g a sma smallll vent vent val valve ve on the the body body of the launcher to atmosphere. 2heck that there is no sound of escaping gas.
;.
-pen the launcher door.
:.
Plac Pl ace e the the pig pig int into o the the laun launche cherr barr barrel el and and pus push h it as far far for forwa ward rd as as poss possibl ible. e.
8.
2lose the launcher door.
7.
2los 2l ose e the the glo globe be val valve ve 31 an and d vent vent iso isola lati tion on va valv lves es 36 an and d 3: 3: on th the e laun launch cher er..
4.
2los 2l ose e th the e ve vent nt va valv lve e 37 and and gl glo obe va valv lve e 38 38..
5.
Pressu Pre ssuri! ri!e e the the lau launch ncher er bar barrel rel by ope opening ning int integr egral al dou double ble blo block ck val valves ves 39 and gra gradua dually lly opening globe valve 3; in the @kicker lineA. -nce the launcher is at the same pressure as the e$port pipeline, close the valves 39 and 3;.
1?.
-pen the lau launch ncher er val valves ves 34 and 35 at the dow downst nstream ream of the laun launche cher. r.
11.
-pen int integr egral al doubl double e block block valve valves s 39 and and globe globe val valve ve 3; 3; in the the launc launcher her @ki @kicke ckerr lineA lineA..
16.
2lose 2lo se the the launche launcherr bypass bypass valv valves es 31? 31? and 311 311.. This This will will launc launch h the pig into into the the e$por e$portt line. line.
19.
2heck 2he ck that that pig sign signals als =>1 and and =>6 =>6 indica indicate te that that the the pig pig has has left left the the launch launcher er barre barrel. l.
1;.. 1;
-pen -p en the the lau launc nche herr bypa bypass ss val valve ves s 31? 31? and and 31 311.
1:.
2lose 2lo se integ integral ral doub double le block block valv valves es 39 and and globe globe valv valve e 3; in in the @kic @kicker ker line lineAA to retu return rn all all flow flow to the bypass line.
18.
2los 2l ose e the the la lau unc nche herr val valve ves s 34 34 and and 35.
17.
-pen val valves ves 36 and and 3: 3: and gra gradua dually lly open open glob globe e valve valve 31 31 to depr depress essuri uri!e !e the the launc launcher her..
14.
-pen ven ventt valve valve 37 37 and glo globe be valve valve 38 to to depres depressur suri!e i!e the pip pipe e spool spool betw between een valv valves es 34 34 and 35.
15.
2lose 2lo se val valves ves 31, 36, 3:, 38 and and 37 37 once once the lau launch ncher er is depr depress essuri uri!ed !ed..
6?.. 6?
Pig Pi g launc launche herr is the then n isola isolate ted d once once pigg piggin ing g opera operati tion on is com compl plet eted ed..
Steps to be followed at pig receiver end 2omplete the following steps to receive a pig at pig receiver. %efer to /igure 6 for all references to numbered valves, pressure gauges and pig signals" 1.
-nce -nc e both both pig sig signal nals s =>1 =>1 and =>6 ind indica icate te tha thatt the the pig has arr arrive ived d in the rec receiv eiver er,, ope open n valv valve e 319.
6.
2los 2l ose e glob globe e valv valve e 38 and and dou doubl ble e bloc block k valv valves es 37 37 and and 34 in in the the rece receiv iver er @ki @kick cker er lin lineA eA..
9.
2los 2l ose e val valve ve 31 316 6 at at the the up upst strrea eam m of of the the re rece ceiv iver er..
;.
-pen val valves ves 36, 39 and 3; and gra gradua dually lly ope open n glob globe e valv valve e 31 31 to to depr depress essuri uri!e !e the rec receiv eiver er and the pipe spool between b etween the receiver valves 311 and 316.
:.
2los 2l ose e va valv lve e 31 311 1 at th the e ups upstr trea eam m of th the e rec recei eive verr.
8.
-nce -n ce pre press ssure ure ga gaug uges es PB1 PB1 and and PB6 PB6 are are sho showi wing ng tha thatt the the rece receiv iver er is is comp comple lete tely ly depressuri!ed, open drain valves 35, 31?, 31;, 31:, 318 and 317 to drain any liquid from the launcher 'and pipe spool between b etween receiver valves( to the drain system.
7.
-pen -p en val valve ve 3: 3: and and the the C*1: C*1: need needle le val valve ve on on the the barr barrel el end end ven ventt line line to to conf confir irm m that that the the receiver is fully depressuri!ed. 2heck that there is n o sound of escaping gas.
4.
-pen -p en th the e doo doorr on on the the re rece ceiv iver er an and d ret retrie rieve ve th the e pig pig fr from om th the e bar barre rel. l.
5.
2lose and secure the receiver door.
1?.
2los 2l ose e ven ventt val valve ves s 31 31, 36, 36, 39 and and 3; 3;..
11.
2los 2l ose e dra drain in va valv lves es 35 35,, 31? 31?,, 31; 31;,, 31: 31:,, 318 318 an and d 317 317..
16.
Pig Pi g re rece ceiive verr is th then en iso sola late ted d.
