refinery.doc

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Chevron's Pascagoula Refinery processes 330,000 barrels (13.9 million gallons) of crue oil a ay ! an

amoun" e#uivalen" "o "he si$e of a foo"ball fiel covere "o a ep"h of %0 fee".

&pera"ors

con"rol "he refining processes using hi!"ech compu"ers loca"e in con"rol cen"ers si"ua"e "hroughou" "he

refinery.

i!ech Process Con"rol

sing "he la"es" elec"ronic "echnology "o moni"or an con"rol "he plan"s, opera"ors run "he process uni"s *%

hours a ay, + ays a ee-. rom con"rol rooms loca"e in each &pera"ions area, opera"ors use a

compu"er!riven process con"rol sys"em i"h console screens "ha" isplay color in"erac"ive graphics of "he

plan"s an real!"ime a"a on "he s"a"us of "he plan"s. he process con"rol sys"em allos opera"ors "o /fine!

"une/ "he processes an respon immeia"ely "o process changes. i"h reunancy esigne in"o "he

con"rol sys"em, safe opera"ions are assure in "he even" of plan" upse".

Refining's asic 2"eps

os" refineries, regarless of comple4i"y, perform a fe basic s"eps in "he refining

process5 DISTILLATION, CRACKING, TREATING anREFORMING. hese processes occur in our main

opera"ing areas 6 Crue78roma"ics, Crac-ing , R:27Co-er, Crac-ing , an a" "he 2ulfur Recovery ni".

1. Distillation

oern is"illa"ion involves pumping oil "hrough pipes in ho" furnaces an separa"ing ligh" hyrocarbon

molecules from heavy ones in ons"ream is"illa"ion "oers 6 "he "all, narro columns "ha" give refineries

"heir is"inc"ive s-ylines.

he Pascagoula Refinery's refining process begins hen crue oil is is"ille in "o large Crue ni"s "ha"

have "hree is"illa"ion columns, one "ha" opera"es a" near a"mospheric pressure, an "o o"hers "ha" opera"e

a" less "han a"mospheric pressure, i.e., a vacuum.


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Clic- on image for :is"illa"ion Column :iagram

:uring "his process, "he ligh"es" ma"erials, li-e propane an bu"ane, vapori$e an rise "o "he "op of "he firs"

a"mospheric column. eium eigh" ma"erials, incluing gasoline, ;e" an iesel fuels, conense in "he

mile. eavy ma"erials, calle gas oils, conense in "he loer por"ion of "he a"mospheric column. he

heavies" "ar!li-e ma"erial, calle resiuum, is referre "o as "he /bo""om of "he barrel/ because i" never really

rises.

his is"illa"ion process is repea"e in many o"her plan"s as "he oil is fur"her refine "o ma-e various

prouc"s.

n some cases, is"illa"ion columns are opera"e a" less "han a"mospheric pressure (vacuum) "o loer "he

"empera"ure a" hich a hyrocarbon mi4"ure boils. his /vacuum is"illa"ion/ (


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ea" an ca"alys"s are use "o conver" "he heavier oils "o ligh"er prouc"s using "hree /crac-ing/ me"hos5

flui ca"aly"ic crac-ing (CC), hyrocrac-ing (soma4), an co-ing (or "hermal!crac-ing).

he lui Ca"aly"ic Crac-er (CC) uses high "empera"ure an ca"alys" "o crac- =>,000 barrels (3.> million

gallons) each ay of heavy gas oil mos"ly in"o gasoline. yrocrac-ing uses ca"alys"s "o reac" gas oil an

hyrogen uner high pressure an high "empera"ure "o ma-e bo"h ;e" fuel an gasoline.

8lso, abou" ?=,000 barrels (*.% million gallons) of ligh"er gas oil is conver"e aily in "o soma4 ni"s, using

"his hyrocrac-ing process.

e blen mos" of "he prouc"s from "he CC an "he soma4es irec"ly in"o "ranspor"a"ion fuels, i.e.,

gasoline, iesel an ;e" fuel. e burn "he ligh"es" molecules as fuel for "he refinery's furnaces, "hus

conserving na"ural gas an minimi$ing as"e.

n "he :elaye Co-ing ni" (Co-er), 9=,000 barrels a ay of lo!value resiuum is conver"e (using "he

co-ing, or "hermal!crac-ing process) "o high!value ligh" prouc"s, proucing pe"roleum co-e as a by!prouc".

he large resiuum molecules are crac-e in"o smaller molecules hen "he resiuum is hel in a co-e rum

a" a high "empera"ure for a perio of "ime. &nly soli co-e remains an mus" be rille from "he co-e rums.

oifica"ions "o "he refinery uring i"s *003 Clean uels Pro;ec" increase resiuum volume going "o "he

Co-er ni". he pro;ec" increase co-e hanling capaci"y an replace "he 1?0 me"ric!"on co-e rums i"h

ne 300 me"ric!"on rums "o hanle "he increase resiuum volume.


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he Co-er "ypically prouces more "han >,000 "ons a ay of pe"roleum co-e, hich is sol for use as fuel or

in cemen" manufac"uring.

Co!ining

hile "he crac-ing processes brea- mos" of "he gas oil in"o gasoline an ;e" fuel, "hey also brea- off somepieces "ha" are ligh"er "han gasoline. 2ince Pascagoula Refinery's primary focus is on ma-ing "ranspor"a"ion

fuels, e recombine 1%,=00 barrels (>**,000 gallons) each ay of ligh"er componen"s in "o 8l-yla"ion ni"s.

his process "a-es "he small molecules an recombines "hem in "he presence of sulfuric aci ca"alys" "o

conver" "hem in"o high oc"ane gasoline.

". Tr#ating $R#o%ing I&'riti#s(

he prouc"s from "he Crue ni"s an "he fees "o o"her uni"s con"ain some na"ural impuri"ies, such as

sulfur an ni"rogen. sing a process calle hyro"rea"ing (a miler version of hyrocrac-ing), "hese

impuri"ies are remove "o reuce air pollu"ion hen our fuels are use.

ecause abou" =0 percen" of "he crue oil processe by "he Pascagoula Refinery is heavier oils "ha" are

high in sulfur an ni"rogen, various "rea"ing uni"s "hroughou" "he refinery or- "o remove "hese impuri"ies.

n "he R:2 ni"'s si4 1,000!"on reac"ors, sulfur an ni"rogen are remove from CC fee s"ream. he sulfur

is conver"e "o hyrogen sulfie an sen" "o "he 2ulfur ni" here i" is conver"e in"o elemen"al sulfur.

@i"rogen is "ransforme in"o ammonia hich is remove from "he process by a"er!ashing. Aa"er, "he a"er

is "rea"e "o recover "he ammonia as a pure prouc" for use in "he prouc"ion of fer"ili$er.

he R:2's ni" main prouc", lo sulfur vacuum gas oil, is fe "o "he CC (flui ca"aly"ic crac-er) ni" hich

"hen crac-s i" in"o high value prouc"s such as gasoline an iesel.

). R#*oring

&c"ane ra"ing is a -ey measuremen" of ho ell a gasoline performs in an au"omobile engine. uch of "he

gasoline "ha" comes from "he Crue ni"s or from "he Crac-ing ni"s oes no" have enough oc"ane "o burn

ell in cars.


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he gasoline process s"reams in "he refinery "ha" have a fairly lo oc"ane ra"ing are sen" "o a Reforming ni"

here "heir oc"ane levels are boos"e. hese reforming uni"s employ precious!me"al ca"alys"s ! pla"inum an

rhenium 6 an "hereby ge" "he name /rheniformers./ n "he reforming process, hyrocarbon molecules are

/reforme/ in"o high oc"ane gasoline componen"s. or e4ample, me"hyl cyclohe4ane is reforme in"o

"oluene.

he reforming process ac"ually removes hyrogen from lo!oc"ane gasoline. he hyrogen is use

"hroughou" "he refinery in various crac-ing (hyrocrac-ing) an "rea"ing (hyro"rea"ing) uni"s.

&ur refinery opera"es "hree ca"aly"ic reformers, here e rearrange an change +1,000 barrels (abou" 3

million gallons) of gasoline per ay "o give i" "he high oc"ane cars nee.

Prouc" "es"ing

+l#ning

8 final an cri"ical s"ep is "he blening of our prouc"s. Basoline, for e4ample, is blene from "rea"e

componen"s mae in several processing uni"s. lening an 2hipping 8rea opera"ors precisely combine

"hese "o ensure "ha" "he blen has "he righ" oc"ane level, vapor pressure ra"ing an o"her impor"an"

specifica"ions. 8ll prouc"s are blene in a similar fashion.

-'alit Control

n "he refinerys moernly!e#uippe Aabora"ory, chemis"s an "echnicians conuc" #uali"y assurance "es"s

on all finishe prouc"s, incluing chec-ing gasoline for proper oc"ane ra"ing. echronDChevrons pa"en"e
http://pascagoula.chevron.com/home/abouttherefinery/whatwedo/processingandrefining.aspx#TB_inline?height=520&width=549&inlineId=p6http://www.chevron.com/products/techron/http://www.chevron.com/products/techron/http://pascagoula.chevron.com/home/abouttherefinery/whatwedo/processingandrefining.aspx#TB_inline?height=520&width=549&inlineId=p6http://www.chevron.com/products/techron/


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performance boos"er, is ae "o gasoline a" "he companys mar-e"ing "erminals, one of hich is loca"e a"

"he Pascagoula Refinery.

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