Challenges_Opportunities_10ppm_1.pdf

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Challenges and opportunities of 10 ppmsulphur gasoline: part 1

The worldwide rening indus-try has undergone a majortransformation in the last

decade due to changes in regula-tory and market forces, such asuctuating crude prices, tighter

regulation on product quality andrenery emissions, shifting crudequality and fundamental changes infuel demands. These forces can beseen clearly in the North Americanmarket, where crude quality has

become heavier due to increasingamounts of lower-cost heavy, sourCanadian bitumen and where regu-lations have become more severe

by limiting the sulphur level infuels to 15 wppm in diesel and 30

wppm in gasoline. In addition tothese feed and product qualitychanges, the overall demand fortransportation fuels is shifting froma traditionally gasoline-oriented toan increasingly diesel-orientedmarket.

Regulatory specications for thegasoline and diesel pool, which areconstantly evolving, have been inthe forefront of reners challengesin the last 10 years. In particular, thegasoline sulphur and benzene regu-

lations have been the main driversfor the recent remodelling of therenery conguration. This transfor-mation has been seen all around theworld, but particularly in Europe,Asia and North America. Othercountries are following the trendand a common worldwide gasolinesulphur specication is on the hori-zon. Indeed, the overall gasolinesulphur content is likely to level offat 10 ppm across the globe. As a

consequence, most reners will facerenewed challenges to be able tomeet the new ultra-low-sulphur

Pspt f wldwd stdd f ULSG d t llgs f sd v

ud suppls dmd ful sdt d slt f gut

DeLPhine LarGeTeaU, Jay roSS, Marc LaborDe d Larry WiSDoM

Axens

gasoline (ULSG) specications.However, in view of other marketforces, there may also be new oppor-tunities for reners.

This article will identify thesenew opportunities by reviewing theprocessing options and conse-quences of such regulation, focusing

mainly on North American rener-ies and drawing on the Europeanand Asian experience of meeting

the 10 ppm ULSG regulations. Theissues, challenges and opportunitiesof each option will be presentedand discussed. In a second article, adetailed economic assessment ofeach conguration will be appliedin a case study.

Gsl sulpu gultThere has been a steady downwardtrend in the sulphur content of fuelsto reduce emissions from cars andtrucks. Many countries mandatedthe production of low-sulphurgasoline (LSG) some time ago, butin recent years regulations inWestern Europe, some Asian coun-tries and California in the US have

brought in even tighter specica-tions to lower the gasoline sulphur

to 10 ppm.The different regional approaches

to the gasoline sulphur specication

www.eptq.com PTQ Q3 2012 43

Countries may apply lower limits for different grades, regions/cities, or based on average content.

Different information on limits and regulations can be found at www.ifqc.org

Fgu 1 Maximum gasoline sulphur limit around the world

Source: International Fuel Quality Center, www.IFQC.org

rg Gsl sulpu, wppmEurope: EU 2005 specication 50EU 2009 specication 10USA: Tier 2 (2004-2006) 30CARB 3 (California) 102010+ CARB 4 (California) 5Japan: 2007 specication 10

cut gsl sulpu spt

Tl 1


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44 PTQ Q3 2012 www.eptq.com

compliance with gasoline sulphurregulations.

Fcc pttmt vs pst-ttmtWhen the Tier 2 regulations wereproposed, many were convincedthat CFHT would be the solution ofchoice due to the resulting largeimprovement in FCC performance.However, the high capital costrequirement for the FCC pretreat-ment option coupled with lowrenery margins resulted in thewide application of FCC post-treat-ment to reduce gasoline sulphur.

Another factor that can inuencethe decision between pretreatmentand post-treatment is FCC ue gasemissions. Limits on renery emis-sions and in particular those fromthe FCC have led to renery-specic

regulation via consent decrees withthe EPA, resulting in much lowerSO

xand NO

xemissions. The

preferred renery congurationmay well have been different hadthe limits on emissions and productsulphur been regulated in concert.

More recently, there has been animportant trend towards the process-ing of increasingly heavier crudes,in particular heavy Canadian crudeor bitumen. By 2015, there is an

expected increase of about 2 millionb/d of Canadian bitumen, whichwill be largely exported to the US asraw bitumen (DilBit) or synthetic

bitumen (SynBit) after partialupgrading at the production site.These very heavy crudes are a chal-lenge for processing in existingrenery assets due to a high acidcontent (TAN), high aromaticity andlow hydrogen content, along withvery high contaminant content:sulphur, nitrogen, Conradson carbon

and metals. A sampling of heavycrude components, which may beconsidered potential FCC feed, areshow in Table 2 to highlight thechallenges of processing bitumen-derived materials.

As a result of these feedstocktrends and a renewed focus oncleaner fuels, lower emissions andeven a shift in gasoline/dieselproduction, the topic of pretreat-ment versus post-treatment is upon

us again. More specically, we willfocus on the pretreat and post-treatissues around the FCC as it relates

set out in Table 1 show a clear trendtowards ULSG. Other countries arefollowing the same path to eithermeet their domestic regulatoryspecications or be able to exportand sell on the international ULSGmarket (see Figure 1).

Although the majority of coun-tries still have gasoline sulphurspecications well above 10 ppm,the overall trend clearly shows that

in the near future ULSG productionwill become the norm worldwide.

cut gutRenery congurations vary widely,depending on crude availability,local demand, export markets andregulatory constraints. In the sameway, each market has its own set ofdynamics and means of complyingwith the new fuel regulations.

In Europe, regulations for ULSG

were adopted early and somewhatinuenced by a market demand,which is more heavily skewedtoward diesel than gasoline. Theoptions for ULSG compliance wereinuenced by: Processing of relatively light andlow-sulphur crude oil Relatively good-quality FCC feed(little cracked gas oil such as heavycoker gas oil)

Undercutting of FCC gasoline tomaximise diesel production.

The EUs 10 ppm ULSG isproduced mainly by using moder-ate severity FCC post-treatment.

Many catalytic feed hydrotreater(CFHT) units installed in Asianreneries were designed to meetmodern fuels and emission regula-tions. As such, many are designedfor high desulphurisation levels to

meet renery and SOx regulationsfrom the FCC ue gas, resultingin low-sulphur FCC gasoline.Consequently, most reneries in

Japan have met the new ULSG limitof 10 ppm by adding low-severitypost-treatment units.

In the US, the renery congura-tion was inuenced by a largedemand for gasoline coupled withlimited fuel oil outlets, resulting inthe installation of bottom-of-the

barrel conversion units and highFCC feed sulphur. The US Tier 2gasoline sulphur and California AirResources Board (CARB) regula-tions led to a sharp increase in thenumber of FCC feed pretreatmentand FCC gasoline post-treatmentunits over a short period of time(see Figure 2). Essentially, all of theUS reneries now have pre- and/orpost-treatment units to ensure

2001 2010

Pre-treat only

Post-treat only

Pre- and post-treatment

Fgu 2 FCC pretreatment and gasoline post-treatment trend in US reneries

cd tum ck hcGo S. tum Mx bld a LgtVGOAPI gravity 13 13 18 22 26Sulphur, wt% 3.3 4-5 1.7 2.2 2.2Nitrogen, ppm 2100 4000 1500 1000 700Hydrogen, wt% 10.7 10.5 11.5 11.7 12.4ATBAPI gravity 5.7 9 6 17Sulphur, wt% 4.9 3.6 3.6 3.1Nitrogen, ppm 5000 3500 3000 1900Hydrogen, wt% 9.2 10.8 9.8 11.4Concarbon, wt% 15.3 11.2 11.6 8.1

Ni + V, ppm 325 200 258 49

Fcc fd qult fm v fds

Tl 2


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to FCC performance, emissions andthe level of product gasoline post-treatment required.

Fcc pttmt ptsThe benets of FCC feed pretreat-ment in a CFHT are well knownand extend beyond simply reduc-ing the sulphur level in the FCCfeed. The reduction in sulphur andother contaminants is helpful interms of reducing the FCC productsulphur level and lowering the uegas emissions from the FCC, butthe interaction with improved feedquality and increased FCC perform-ance is also very important.Environmental regulations, and inparticular the need to produce verylow-sulphur gasoline, have putincreased emphasis on CFHT

performance and reliability.Concurrently, a lower demand

for fuel oil coupled with theprocessing of heavier crudes hasresulted in the installation of resi-due conversion units such asdelayed cokers. These conversionunits produce signicant amountsof hydrogen-decient, heteroatom-rich (N and S) vacuum gas oils(VGO, HCGO), which need to bedeeply hydrotreated prior to

conversion in the FCC unit.As a result, modern CFHT unitsneed to process increasingly morerefractory feedstocks while achiev-ing high desulphurisation levels tomeet gasoline sulphur specica-tions. The increased contaminantsalso make it more difcult for theCFHT to upgrade the quality of theFCC feed to maintain the requiredyield of gasoline and LPG. In addi-tion to the objective ofhydrodesulphurisation, hydrodeni-

trogenation and polynucleararomatics (PNA) saturation, theprocessing of cracked stocks in aCFHT, often with high end-point tomaximise renery economics,requires a careful selection of thecatalytic system to take into accountthe potential for higher metals(nickel, vanadium, arsenic, silicon)and asphaltenes, along with thehigher fouling propensity of thesearomatic-rich feeds.

On the other hand, this problemcan turn into an opportunity toincrease the severity of the CFHT,

not only to meet sulphur targetsbut also to change the diesel-to-

gasoline ratio by operating in mildhydrocracking (MHC) mode andtaking advantage of low-cost natu-ral gas to further increase volumeswell. These adjustments willrequire some modications to theoperating conditions, selection ofthe optimum catalytic system anddistributor internals, increasedhydrogen consumption and likelyupgrades throughout the unit. Oneof the challenges of operating in the

MHC mode is the ability to meetultra-low-sulphur diesel (ULSD)specications throughout the MHCcycle. Moderate-pressure MHCunits generally do not meet therequired diesel specications, there-fore post-treatment is required. Oneoption to meet this challenge is theHyC-10 technology developed byAxens to integrate diesel upgradingwithin the MHC high-pressure loopwhile decoupling operating condi-tions.1,2 Another important factor in

MHC/CFHT design is the ability tomaintain desulphurisation targetswhile meeting optimum VGO qual-ity throughout the cycle length.

In conclusion, a deep understand-ing of the feedstock type and thechemical reactions involved in aCFHT (kinetics, thermodynamics,contamination/poisoning) coupledwith their impact on the FCC oper-ation is paramount to selectingoptimum CFHT operating condi-

tions and design of the optimumcatalyst system. The followingsection will examine the inuence

of the CFHT operation on the FCCunits performance.

impt f cFhT Fcc pfmThe FCC unit has long been theworkhorse in the renery to achieverelatively low-cost conversion ofheavy crude components (VGO,HCGO and some atmospheric resi-due) into gasoline, butenes forhigh-octane alkylate production,propylene and LCO diesel blendcomponents. Although the chemis-try and catalyst systems can be

complex, generally speaking theFCC unit is a hydrogen redistribu-tion system with some carbonrejection as coke, which is consumedin the process. The performance ofthe FCC unit and the yield of valua-

ble products is therefore linked tothe hydrogen content of the feed.This trend is shown in Figure 3,where the conversion potential andgasoline yield increase sharply withthe hydrogen content of the feed.

The CFHT therefore plays a vital

role in improving the FCC feedquality to enhance the yield andoverall renery protability. As thefeed contaminants of sulphur andnitrogen are reduced to improveproduct quality and reduce FCCemissions, multi-ring aromatics aresaturated and the crackability of thefeed increases. Sharp gains inconversion and gasoline yield resultfrom the rst incremental increasein hydrogen and there is some

degree of diminishing returns (seeFigure 3). When propylene yield isof interest, the increased hydrogen

65

85

80

75

70

60

55

50

45

40

10.5 11.0 11.5 12.0 12.5 13.0 13.5

wt%

Feed hydrogen, wt%

35

12

20

18

16

14

10

8

6

4

2

wt%

0

Propyl

enepo

tential

Fuel oil

Conversion

Gasoline

Fgu 3 FCC yield vs feed hydrogen content


4/8

in the gasoline decreases. Figure 4shows this general trend for feedsthat are hydrotreated and for non-hydrotreated feeds of varyingsulphur content.

If one were to target the newULSG pool sulphur level of 10 ppm,the CFHT must reduce the feedsulphur to about 200-300 ppm,considering a ratio of between 20:1and 30:1 of the hydrotreated feedsulphur to the gasoline sulphur.This will be true even if we considerthat the FCC gasoline is only aboutone-third of the pool and the other

blend stocks are nearly sulphur-free, as reners will leave somemargin below 10 ppm to ensurecompliance.

When looking at the sulphur inFCC gasoline, one needs to be very

clear about the gasoline cut pointand the distillation tail on theproduced gasoline product. InFigure 5, we can see a carefullyanalysed commercial FCC gasolineand the cumulative full-range gaso-line sulphur versus true boilingpoint (TBP).

Figure 5 clearly demonstrates theimportance of dening the gasoline

boiling range when discussing thesulphur level. In the US market,

gasoline has been traditionallyover-cut relative to the standard430F (220C) cut and oftenextended to 450-480F (230-250C),thereby including not only benzo-thiophene but also somemethyl-benzothiophenes in thegasoline. These compounds enterthe gasoline cut just at the standardcut point and complicate accuratemeasurement of gasoline sulphurfrom non-ideal industrial samples.With the increased interest in distil-

late production, undercutting thegasoline to less than 430F willsignicantly help control thesulphur level when producingULSG, as is done in Europe.

Considering the dependence ofFCC gasoline on both CFHTperformance and precise fractiona-tion of the gasoline product,meeting ULSG targets throughCFHT alone is possible but chal-lenging. There will be little room

for error or deterioration in CFHTperformance over the course of aproduction run or cycle.


input is always benecial, and inmany cases high hydrogen inputcan be justied, particularly whenhydrogen is relatively inexpensive.3

As the severity of the CFHTincreases, there is also the opportu-nity for co-produced diesel in theCFHT via mild hydrocracking toshift the overall renery balance

between gasoline and diesel.Dening the optimal balance

between severity, hydrogen input,cracking and FCC mode of opera-

tion within the existing constraintsof a renery conguration is there-fore very complex.

Within the context of ULSG, themore traditional role of the CFHTto consider is that of desulphurisa-tion and the impact on the FCCgasoline produced. As the sulphurcontent in the FCC unit feed

decreases and the extent of feedhydrotreating increases, the typesof sulphur left in the FCC feed alterand the amount of sulphur found

60

100

80

40

20

25 50 75 100 125 150 175 200 225 250

Cumulativesulphur,%

Temperature, C

0

Thiophene

C1-Thiophene

C2-Thiophene

Benzo-

Thiophene

Alkyl-Benzo-

Thiophene

S

S

Mercaptans

Fgu 5 FCC Gasoline sulphur prole

Tpl Fd sulpu, wppm Pdut sulpu, wppmWestern Europe 200-1000 10-20North America 500-2000 30-50California 100-300 10-20South America 500-2000 30-100

Japan/Korea 50-200 10

Fcc gsl pst-ttmt ut dsg

Tl 3

1000

10000

100

10

0.01 0.1 1 10

Gaso

lineS,wtppm

Feed sulphur, wt%

1

Hydrotreated

Straight run

Fgu 4 FCC Gasoline sulphur vs feed sulphur and treatment


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Fcc pst-ttmt pts tmt ULSGIn order to comply with low-sulphur gasoline regulations, amajority of reners across the worldhave already invested in a FCCpost-treatment unit. However,processing schemes vary greatlyfrom one site to another, depending

on sulphur specication, overallrenery conguration and crudediet (see Table 3).

Most reneries in California andJapan are equipped with FCC feedpretreaters, which explains the lowsulphur level in FCC naphtha.Conversely, FCC naphtha sulphurtends to be high in the Americas,and high-severity post-treaters will

be required to meet the 10 ppmgasoline sulphur target.

The Prime-G+ process selectivelydesulphurises FCC full-range naph-tha (FRCN) while ensuring minimal

octane loss. It is a widely usedcracked gasoline desulphurisationtechnology, with over 190 licensedunits throughout the world.4 Thetechnology has proven to be highlyexible, with several Prime-G+processing schemes offered accord-ing to the targeted severity of theunit (see Figure 6).

expltg xstg Pm-G+ utsDepending on the existing Prime-G+ conguration, meeting newULSG regulations at 10 ppm whileusing the existing assets could beachieved in different ways. First,one potential solution that does notrequire any additional investmentwould be to simply increase sever-ity (essentially reactor temperature)to lower the existing Prime-G+

product sulphur. The increasedHDS level would lead to a higheroctane loss and hydrogen consump-

tion, coupled with a potential cyclelength reduction. Switching tohigher selectivity and activityPrime-G+ catalysts may help miti-gate these drawbacks, but couldprove insufcient in many cases.

Another solution would involvethe co-processing of other sulphur-rich streams in the Prime-G+ unit

that previously did not require anytreatment to meet the earliersulphur specications. The streamscould be light such as light cokernaphtha or visbroken naphtha thatcan be handled in the rst step(selective hydrogenation unit SHU and splitter section). Light,straight-run naphtha, natural gaso-line could also be co-processedeither in the SHU upstream of thesplitter or directly in the HDS

section. One of the drawbacks ofco-processing is possible hydraulicslimitations in the unit. In addition,


SHU HDTULSG

FCC

FRN

Low/moderate HDS

Prime-G+ 1-stage HDS

Moderate/high HDS

SHUHDT

1&2

ULSG

FCC

FRN

Prime-G+ 2-stage HDS

SHU

HDT

ULSG

FCC

FRN

Prime-G+ 1st step (SHU & splitter) / 1-stage HDS

Very high HDS

SHU

HDT

1&2

ULSG

FCC

FRN

Prime-G+ 1st step (SHU & splitter) / 2-stage HDS

Fgu 6 Prime-G+ processing schemes


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adding sulphur-rich streams couldlead to a higher HDS level coupledwith a higher octane loss and,again, the potential for a reducedcycle length.

An alternative option would be todecrease the Prime-G+ feed sulphurto maintain a similar HDS levelacross the unit to ensure constantoctane loss and cycle length.Lowering the feed sulphur could be

achieved in different ways. Theshort-term solutions would be touse sulphur reduction additives inthe FCC unit or to process low-sulphur crudes. Both of theseoptions have limitations and aregenerally not practical for a signi-cant sulphur reduction without aheavy penalty on renery exibil-ity. More realistically, a reductionin the FCC naphtha end-point orchanges in the CFHT could be envi-sioned to reduce the sulphur in the

FCC naphtha. In Western Europe, itis common to reduce the FCC naph-tha end-point, as it also maximisesdiesel production to meet marketdemand.

rvmpg Fcc pst-ttmtutsAs most reneries are equippedwith a FCC post-treatment unit tocontrol gasoline sulphur, it isinstructive to take a closer look at

the revamping options around theselective FCC naphtha desulphuri-sation unit to meet the new ULSG

requirements. There are a numberof ways to revamp an existingselective FCC naphtha desulphuri-sation unit to meet tighter sulphurspecications, which display differ-ent levels of complexity andassociated cost: Option 1: Install a Prime-G+ rststep if not existing Option 2: Add a SHU (selectivehydrogenation unit) or HDS reactor

if the cycle length is a limitation forthe new product sulphur target Option 3: Route the medium cata-lytic naphtha (MCN) cut to theNHT/reformer Option 4: Process the mediumcatalytic naphtha (MCN) and theheavy catalytic naphtha (HCN)streams separately Option 5: Install a second-stageHDS section.

In option 1, the installation of aFCC naphtha splitter downstream

of the existing (or new) SHU is thePrime-G+ rst step. The SHU oper-ating conditions and catalyst designallow for the selective hydrogena-tion of diolens, which may foulthe desulphurisation section, andalso the conversion of light sulphurspecies such as mercaptans to heavy

boiling sulphur compounds. As aresult of the chemical reactionstaking place in the SHU, the down-stream splitter produces a sweet,

low-sulphur, light catalytic naphtha(LCN) stream rich in olens and aheavy FCC naphtha (HCN), which

is routed to the HDS section. Sucha HCN stream with its lower olenscontent can be selectively desul-phurised through the use of tailoredcatalysts to meet the ULSG targetwhile controlling olens saturationand thus octane loss. Addition ofthe splitter reduces the throughputto the HDS section and hydrogenconsumption. This solution alsoallows the co-processing of otherstreams containing sulphur, such ascoker naphtha, visbroken naphtha,straight-run naphtha or naturalgasoline.

For option 2, the addition of aSHU upstream of an existing split-ter will produce a sweetlow-sulphur LCN stream andprovide benets similar to thosedescribed in option 1. In case cycle

length becomes limited, implemen-tation of an additional HDS reactorin series with the existing one can

be envisioned. Options 1 and 2 areeasy to implement and lead tomoderate capital expenditure. Thetypical block ow diagram ofOption 3 is shown in Figure 7.

This option involves revampingthe existing splitter into a three-cutcolumn in order to withdraw aheart cut (MCN) rich in olens that

contains some sulphur and exhibitsa moderate octane number (espe-cially MON). The MCN is thenmixed with the normal feed to theNHT unit and reformer unit.Sending the MCN to the reformerwill lead to a gasoline octane gain.However, there may be limitationsin terms of capacity for both NHTand reformer sections that need to

be carefully assessed and taken intoaccount for the evaluation of theoverall revamp cost. In addition,

potential increased benzene produc-tion in the reformer could lead toissues in meeting the MSAT II gaso-line benzene specications. Theaddition of an integrated reformatesplitter/benzene hydrogenation(Benfree) resolves this issue.5

While this solution offers someadvantages in terms of octane, thedecreased gasoline yield shouldalso be considered. Overall, thisoption may be attractive, but has

more implications than just makingmodications to the existing FCCpost-treatment section.


NHT

Prime-G+

Reformer

SRN

HCN

FRCN

LCN

MCN

HCN

Coker N

Isom

Splitter

Splitter

Benfree

MoGas

pool

Fgu 7 FCC naphtha heart cut (MCN) to reformer


7/8

Decoupling of the MCN andHCN can also be utilised to treatthese streams in two separate selec-tive HDS sections. This is option 4and is illustrated in Figure 8.

This innovative and patentedscheme by Axens has the additionaladvantage of offering greater exi-

bility to route the desulphurisedHCN either to the MoGas or dieselpool, according to the economics ofthe renery.6 Both MCN and HCNselective HDS sections are designedto minimise octane loss whileachieving 10 ppm product sulphur.Compared to the previous option,option 4 incurs more revampingcosts, as a new MCN HDS sectionneeds to be installed. But the addi-tional cost could be easily offset bythe improved octane retention

compared to treating the combinedMCN and HCN in a single one-stage selective HDS section at ULSGlevels and by the additional exibil-ity that this option offers.

The last option explored here,option 5, is the inclusion of asecond-stage HDS section to mini-mise octane loss and maintain oreven increase the catalyst cyclelength. The typical block owdiagram is shown in Figure 9.

Although the splitter is shown hereupstream of the HDS section, Axensalso has experience of designing atwo-stage HDS section on full-rangeFCC naphtha with no upstreamsplitter.

In a typical one-stage HDS cong-uration, olens saturation, and thusoctane loss, increases rapidly above98% HDS. At a high HDS level, theaddition of a second-stage HDSsection helps improve octane reten-tion and minimise hydrogen

consumption.Several Prime-G+ units have been

designed for two-stage operationand many are in operation.Although this option requires addi-tional capital investment, there is areal incentive to pursue this solu-tion when the renery is octanetight or hydrogen constrained.

These options provide commer-cially proven solutions for renersto meet new ULSG specications

with existing or modied post-

treatment units. In view of the lowrenery margins and octane-long

position resulting from the ethanolmandate, the debottlenecking of aselective FCC naphtha desulphuri-

sation unit will likely be thepreferred solution for many ren-ers, assuming no signicant changesin their crude diet.

A number of reners are,however, envisioning the process-ing of heavy crudes such as thosederived from Canadian oil sandsdue to their lower cost coupledwith geopolitical reasons. Processingof these heavy crudes requires acomplete renery reconguration

with bottom-of-the-barrel conver-

sion units such as coking orebullated-bed hydrocracking. Aswas discussed earlier, the resultingVGO and HCGO streams are veryrefractory with high levels ofsulphur and nitrogen and a verylow hydrogen content. Such feedsrequire deep pretreatment prior to

feeding the FCC unit to maintainacceptable yields. Since FCCpretreatment (CFHT) is mandatory

in those cases, one may wonderwhether a post-treatment unit isrequired or not. In a second article,an economic evaluation will illus-trate the pros and cons of FCCpretreatment only or in combina-tion with post-treatment.

clusNorth American reneries need toadapt to tightening sulphur speci-cations and the prospect of ULSG

at 10 ppm. This challenge will beexacerbated by the increasedproportion of heavy crudes and thegasoline/diesel imbalance. Thisarticle has presented commerciallyproven congurations that areavailable to meet these constraintsand maintain protability. A combi-nation of pre- and post-treatment


Prime-G+selective

hydrogenation

SHU

SplitterFRCN

H2

make-up

HCN150F+

Ultra-low-sulphurgasoline to MoGas

H2S

1st stage

HDS

2nd stage

HDS

Ultra-low S LCN to Pool,TAME or Alky Unit

Prime-G+

selective

hydrogenation

SHU

SplitterFRCN

MCN

HDS

HCN

HDS

Processintegration

Ultra-low S LCN to Pool,TAME or Alky Unit

ULS MCN:150-300F to MoGas

ULS HCN:300F-FBP to

MoGas or diesel

Fgu 8 Decoupling MCN and HCN processing

Fgu 9 Revamp of Prime-G+ HDS into two-stage conguration


8/8

may be necessary, depending on the initial reneryconguration, local market demands, emissions regula-tions and the crudes processed.

A second article will present a detailed economicevaluation to allow comparison of the costs and returns

between the FCC feed pretreatment alone and post-treatment options, as well as the optimumdesulphurisation and cycle length for the CFHT whenconsidered in combination with a post-treatment.These congurations will be applied in the context of arenery being revamped to process heavy Canadiancrudes and maintaining its FCC unit. The VGO feed-stock considered for this economic evaluation will be a55 000 b/d blend of straight-run VGO and heavy cokergas oil with 4.2 wt% sulphur.

rfs

1 Bonnardot J, et al, Direct Production of Euro-IV Diesel at 10 pm Sulphur

via the HyC-10 Process, ERTC 9th Annual Meeting, Nov 2004.

2 Sarrazin P, et al, New mild hydrocracking route produces 10-ppm-

sulphur diesel, Hydrocarbon Processing, Feb 2005.3 Roux R, et al, Resid to Petrochemicals Technology, ERTC 13th Annual

Meeting, Nov 2008.

4 Debuisschert Q, Prime-G+ Commercial Performance of FCC Naphtha

Desulphurization Technology, AM-03-26, NPRA Annual Meeting, Mar

2006.

5 Largeteau D, et al, Benzene Management in a MSAT 2 Environment,

AM-08-11, NPRA Annual Meeting, Mar 2008.

6 Debuisschert Q, et al, Technology Solutions addressing gasoline and

diesel imbalances, Platts European Rening Market 4th Annual Meeting,

Sept 2010.


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Challenges_Opportunities_10ppm_1.pdf